@article {JRN55413, title = {Simulated distribution of Eragrostis lehmanniana (Lehmann lovegrass): Soil{\textendash}climate interactions complicate predictions}, journal = {Ecosphere}, volume = {13}, year = {2022}, month = {3/7/2022}, pages = {e3974}, abstract = {The invasive perennial grass Eragrostis lehmanniana has expanded rapidly throughout the Sonoran Desert (SD) while remaining sparse and patchily distributed in the neighboring Chihuahuan Desert (CD). As temperatures and patterns in precipitation change, identifying the drivers limiting spread in the CD is needed. Our objectives were (1) to identify the climatic and edaphic factors limiting recruitment of E. lehmanniana throughout the CD and (2) to predict the edaphic and climatic locations in the CD where this species is expected to have higher probabilities of recruitment under future climatic conditions. Recruitment was simulated at 57 locations throughout the CD with a daily, multilayer soil water model (SOILWAT) that was parameterized and tested to develop recruitment parameters for E. lehmanniana using long-term data from research stations in the SD and CD. Logistic regression was used to predict recruitment across the CD using climate and soil factors to create a map of simulated recruitment under current and alternative climate scenarios. Simulated recruitment under current climate was low for most of the CD. However, localized areas with high probabilities (>0.8) occurred along the western transition between the CD and the SD, and in the southern extent of the CD. In general, the CD climate is too cool and dry for rapid and widespread invasion. However, increases to temperature and precipitation are likely to increase recruitment success. Interactions among soil, tempera-ture, and precipitation were important to increases in recruitment of E. lehmanniana and are expected to lead to heterogeneous increases in abundance as climate continues to change. This patchy increase in abundance will result in changes in its geographic distribution that will make predictions in the future challenging.}, keywords = {Chihuahuan Desert, climate change, Geographic distribution, numerical model, recruitment, seedling establishment, Special Feature: Dynamic Deserts}, doi = {10.1002/ecs2.3974}, url = {files/bibliography/22-022.pdf}, author = {N. Dylan Burruss and Debra.C.P. Peters and Haitao Huang and Jin Yao} } @proceedings {JRN55433, title = {Studying the impacts of dust emission and dust deposition on snow over the Upper Colorado River Basin using the WRF-Chem-CTSM coupled framework}, year = {2022}, abstract = {Water resources in the Upper Colorado River Basin are strongly related to the timing and magnitude of seasonal snowmelt. However, the impacts on the regional water and energy cycles due to dust-on-snow events, which accelerate snowmelt and may reduce total water yield, have yet to be fully investigated. To address this issue, we introduce a fully coupled land-atmosphere framework which can be used to study the relationship between dust, snow, and water resources. We couple the Weather Research and Forecasting model with Chemistry (WRF-Chem) and the Community Terrestrial System Model (CTSM) through the Lightweight Infrastructure for Land Atmosphere Coupling. WRF-Chem simulates dust emission, transport, and deposition while CTSM simulates changes in the hydrologic cycle due to the dust deposition. To better represent the processes, we also 1) incorporate a satellite measured albedo-based drag partition parameterization into the Air Force Weather Agency dust emission module for WRF-Chem consistent with LeGrand et al. (2022); 2) update the Snow, Ice, and Aerosol Radiative model which simulates snow albedo in CTSM; 3) redistribute dust size bins according to onsite observations to solve the mismatch of WRF-Chem and CTSM. In this study, we perform a high-resolution month-long coupled simulation that includes strong dust-on-snow events in April 2013 over the southwest US. For simulation, a triply-nested domain with horizontal resolutions of 18, 6, and 2 km are selected to fully cover dust sources and ensure high resolution for the impacted region while maintaining computational efficiency. We run CTSM offline for 5 years to spin-up the land surface model and provide the initial conditions for a month-long coupled simulation. After that, offline CTSM is run to continue simulating the resulting hydrologic processes. The simulation is compared with the baseline simulation where dust is not included in the system. This comparison will further help clarify the regional hydrological impact of US southwest{\textquoteright}s dust-on-snow events during April 2013. }, author = {Jiaxuan Cai and Saroj Dhital and Nicholas Webb and S. McKenzie Skiles and Patrick Naple and Travis W. Nauman and Danielle Duni and Susan LeGrand and Theodore W. Letcher and Nathaniel W. Chaney} } @article {JRN55431, title = {A statistical approach to using Remote Sensing Data to Discern Streamflow Variable Influence in the Snow Melt Dominated Upper Rio Grande Basin}, journal = {Remote Sensing}, volume = {14}, year = {2022}, month = {11/30/2022}, pages = {6076}, abstract = {Since the middle of the 20th century, the peak snowpack in the Upper Rio Grande (URG) basin of United States has been decreasing. Warming influences snowpack characteristics such as snow cover, snow depth, and Snow Water Equivalent (SWE), which can affect runoff quantity and timing in snowmelt runoff-dominated river systems of the URG basin. The purpose of this research is to investigate which variables are most important in predicting naturalized streamflow and to explore variables{\textquoteright} relative importance for streamflow dynamics. We use long term remote sensing data for hydrologic analysis and deploy R algorithm for data processing and synthesizing. The data is analyzed on a monthly and baseflow/runoff basis for nineteen sub-watersheds in the URG. Variable importance and influence on naturalized streamflow is identified using linear standard regression with multi-model inference based on the second-order Akaike information criterion (AICc) coupled with the intercept only model. Five predictor variables: temperature, precipitation, soil moisture, sublimation, and SWE are identified in order of relative importance for streamflow prediction. The most influential variables for streamflow prediction vary temporally between baseflow and runoff conditions and spatially by watershed and mountain range. Despite the importance of temperature on streamflow, it is not consistently the most important factor in streamflow prediction across time and space. The dominance of precipitation over streamflow is more obvious during baseflow. The impact of precipitation, SWE, sublimation, and minimum temperature on streamflow is evident during the runoff season, but the results vary for different sub-watersheds. The association between sublimation and streamflow is positive in the runoff season, which may relate to temperature and requires further research. This research sheds light on the primary drivers and their spatial and temporal variability on streamflow generation. This work is critical for predicting how warming temperatures will impact water supplies serving society and ecosystems in a changing climate. }, keywords = {snowmelt runoff; second-order Akaike information criterion (AICc); streamflow dynamics; remotely sensed data; Upper Rio Grande}, doi = {10.3390/rs14236076}, url = {files/bibliography/22-028.pdf}, author = {Khandaker Iftekharul Islam and Emile H. Elias and Christopher Brown and D. K. James and Sierra Heimel} } @article {JRN55390, title = {The social networks of manureshed management}, journal = {Journal of Environmental Quality}, year = {2022}, month = {02/09/2022}, abstract = {Manureshed management{\textemdash}the strategic use of manure nutrients that prioritizes recycling between livestock systems and cropping systems{\textemdash}provides a comprehensive framework for sustainable nutrient management that necessitates the collaboration of many actors. Understanding the social dimensions of collaboration is critical to implement the strategic and technological requirements of functional manuresheds. To improve this understanding, we identified aspirational networks of actors involved in manureshed management across local, regional, and national scales, principally in the United States, elucidating key relationships and highlighting the breadth of interactions essential to successful manureshed management. We concluded that, although the social networks vary with scale, the involvement of a common core set of actors and relationships appears to be universal to the successful integration of modern livestock and crop production systems necessary for functional manuresheds. Our analysis also reveals that, in addition to agricultural producers, local actors in extension and advisory services and private and public sectors ensure optimal outcomes at all scales. For manureshed management to successfully integrate crop and livestock production and sustainably manage manure nutrient resources at each scale, the full complement of actors identified in these social networks is critical to generate innovation and ensure collaboration continuity.}, keywords = {manureshed management, NGO, non-governmental organization, social networks}, doi = {10.1002/jeq2.20334}, url = {files/bibliography/21-061.pdf}, author = {Gwendwr Rhiannon Meredith and S. Spiegal and Peter J. A. Kleinman and R. Daren Harmel} } @article {JRN55384, title = {Soil loss and PM10 emissions from agricultural fields in the Junggar Basin over the past six decades}, journal = {Journal of Soil and Water Conservation}, volume = {77}, year = {2022}, month = {3/10/2022}, pages = {113-125}, abstract = {The Junggar Basin in north Xinjiang Province is regarded as one of the important dust sources in China. There is, however, a lack of information on long-term dust emissions originating from the basin. In these largely agricultural communities, wind erosion is a major concern that results in a threat to sustainable agriculture and environmental quality. This study assesses dust emissions from the agricultural community of the Junggar Basin in north Xinjiang based on soil and land use types extracted from remote sensing data in response to weather and climate over the past six decades. The Wind Erosion Prediction System (WEPS) was used to simulate annual soil loss and PM10 (particulate matter <=10 μm in aerodynamic diameter) emissions at 11 meteorological stations across the Junggar Basin. From 1958 to 2018, annual soil loss and PM10 emissions significantly decreased 3.65 and 0.2 kg m{\textendash}2 y{\textendash}1, respectively. This decrease was likely due to decreasing wind speed, but also associated with increased precipitation and temperature, and decreased solar radiation. Wind erosion occurred most frequently during April and May, accounting for 39\% of the annual soil loss and 40\% of the annual PM10 emission. In contrast, no erosion occurred in January, February, and December as a result of low temperature (<{\textendash}8.6{\textdegree}C), frozen soil conditions, and snow cover. Wind erosion risk appeared to decrease during the past six decades in response to observed climate change across the basin; however the southeast part of the basin experienced increasing wind erosion risk over the six decades. Projects to control wind erosion risk and combat dust emission should be given priority in the southeast part of the basin. Frequency of dust events was compared to simulated erosion; a strong linkage was found between simulated soil loss and frequency of dust storms based on regression analysis. This demonstrated that the modelling was acceptable in the conditions of this study and the results were prone to be reliable.}, keywords = {climate, dust emission, land use types, soil types, weather, WEPS}, doi = {10.2489/jswc.2022.00018 }, url = {files/bibliography/22-013.pdf}, author = {H. Pi and Nicholas Webb and J. Lei and S. Li} } @proceedings {JRN55362, title = {Sustainable Southwest Beef: Evaluating innovations from pasture to plate}, year = {2022}, month = {2/8/2022}, abstract = {Consumers and producers worldwide are paying attention to the environmental and social impacts of the beef industry, demonstrating preferences for beef produced with high standards of animal welfare, environmental quality, and well-being of agricultural communities. At the same time, major pressures such as climate change impacts, market variation, and disease complicate prospects for achieving the environmental, social, and economic targets that result in sustainable beef production systems. Climate impacts are especially pronounced in the Southwestern US: as temperatures rise and rainfall becomes more erratic, forage production is decreasing and ranching input costs are increasing. Also, this region is dependent on other regions for finishing its ranch-raised cattle {\textendash} and ultimately for marketing the beef from the cattle originating in the Southwest. A team of 25 organizations led by New Mexico State University and funded by the National Institute of Food and Agriculture is exploring the performance of three management strategies with promise to improve sustainability outcomes in these conditions: heritage cattle genetics, digital ranching, and alternative finishing options include grassfinishing on southwestern rangeland and recycling the feedlot manure produced by cattle that originate on southwestern ranches. We will introduce our integrated research/extension/education approach and describe how we are using a supply chain perspective to understand and communicate the tradeoffs of the three strategies under investigation, from pasture to plate. We will also provide context for the other talks and discussions in the symposium and make sure the attendees are well prepared to enjoy and learn with the SRM community in the session.}, author = {S. Spiegal and Andr{\'e}s F. Cibils and Jean Steiner and Richard E. Estell and Brandon T Bestelmeyer and Matthew M. McIntosh and Stephanie Bestelmeyer and Skye Aney and Emile H. Elias and G. Duff} } @booklet {JRN55376, title = {sample.design}, year = {2022}, month = {Zenodo}, abstract = {One of the major components of ecological research and land management is data collection. Creating sampling designs which are statistically valid and intercompatible can be difficult. The R language software package sample design contains a collection of functions which can be used to facilitate the creation of statistically valid and spatially balanced sampling designs. These include functions for checking the spatial balance of sampling designs, determining how to allocate sampling effort, combine multiple sampling designs, and more. The package sample.design currently in use by the Bureau of Land Management as part of their Assessment, Inventory, and Monitoring program.}, doi = {10.5281/zenodo.6518745}, author = {Nelson Stauffer and S. L. Garman} } @article {JRN55389, title = {A synthesis of ranch-level sustainability indicators for land managers and to communicate across the US beef supply chain}, journal = {Rangeland Ecology \& Management}, volume = {79}, year = {2021}, month = {10/19/2021}, pages = {217-230}, abstract = {While increasing numbers of ranchers are striving to demonstrate sustainable ranching operations geared toward a healthy landscape, companies are seeking to advance sustainability along beef supply chains and consumers are making more environmentally oriented purchasing choices. Yet there is a need for greater clarity on which indicators are most effective for assessing and monitoring sustainable management and continuous improvement of ranching operations. Our objective was to synthesize existing guidance on monitoring and assessing ranch-scale sustainability in the United States and to identify core ecological, social, and economic indicators that could identify well-managed ranching, support adaptive management, and demonstrate producers{\textquoteright} sustainability and continuous improvement to retailers and consumers. We evaluated 21 range and pastureland assessments from nongovernmental organizations, agencies, and academics that totaled 180 indicators. From this, we selected 20 commonly used {\textquotedblleft}core{\textquotedblright} indicators (12 ecological and 8 socioeconomic). We identified indicators that are designed to detect change over time for management practices, common among many approaches, and/or critical indicators for outcomes of common interest to producers, companies, and consumers. The synthesis of indicators across many guidance documents offers insight into what a diverse set of range professionals and institutions see as critical to demonstrate and track ranch-level sustainability, and producers, consumers, and companies may find a subset of these indicators to be relevant for their operation and region, values, and/or company sustainability goals. The synthesis also highlights the need for more integration and agreement on socioeconomic indicators of ranch sustainability. We acknowledge that socioeconomic indicators are context dependent and discuss the pitfalls of not integrating them into ranch assessments. Finally, we identified four issues to consider in operationalizing widespread use of common indicators: 1) who bears the cost, 2) agreement on simple and robust standardized protocols, 3) developing region-specific thresholds, and 4) issues of data privacy and sharing agreements for data use.}, keywords = {beef supply chain, ecological, economicmeasures, social, sustainable rangelands}, doi = {10.1016/j.rama.2021.08.011}, url = {files/bibliography/21-062.pdf}, author = {Marissa A. Ahlering and Clare Kazanski and Patrick E. Lendrum and Pablo Borrelli and William Burnidge and Lexi Clark and Chad Ellis and Kirk Gadzia and Jonathan Gelbard and Sasha Gennet and Jeff Goodwin and Jeffrey E. Herrick and Emily Kachergis and Corrine Knapp and Nancy Labbe and Kristie Maczko and Elizabeth Porzig and David Rizzo and S. Spiegal and Christopher Wilson} } @inbook {JRN55317, title = {State-and-transition modelling}, booktitle = {The Routledge Handbook of Research Methods for Social-Ecological Systems}, year = {2021}, pages = {371-382}, chapter = {27}, abstract = {Chapter 27 considers state-and-transition models (STMs), which are tools to explain the causes and consequences of ecosystem change. The chapter discusses general types of STMs, including conceptual STMs, spatial and non-spatial state-and-transition simulation models, process-based STMs and ecosystem service-based STMs. It goes on to discuss the types of social-ecological systems (SES) problems and research questions commonly addressed by this set of methods, as well as their limitations, resource implications and new emerging research directions. The chapter also includes an in-depth case study showcasing the application of STMs, and suggested further readings on these methods.}, keywords = {State-and-transition modelling}, isbn = {9781003021339}, doi = {10.4324/9781003021339-32}, url = {files/bibliography/21-032.pdf}, author = {Brandon T Bestelmeyer and Maria Fern{\'a}ndez-Gim{\'e}nez and Bulgamaa Densambuu and Retta Bruegger} } @article {JRN55292, title = {Shrub encroachment, landscape restoration, and intraguild predation}, journal = {Journal of Arid Environments }, volume = {193}, year = {2021}, month = {July 10, 2021}, abstract = {Shrub encroachment into arid grasslands occurs globally with the potential to affect vertebrates and their interactions. In the Chihuahuan Desert of southern New Mexico, shrub encroachment has prompted intensive efforts by land management agencies to remove shrubs and restore historical grassland habitats. We asked if restoration actions involving shrub removal affected dynamics of intraguild predation (IGP) including an IGP predator (coyote, Canis latrans), an IGP prey (kit fox, Vulpes macrotis), plus their shared lagomorph prey. We used camera traps on 14 sites with paired treated and untreated areas to examine spatial and temporal niche partitioning of coyotes and kit foxes. Shrub removal did not produce straightforward effects on abundances of coyotes, kit foxes, or their prey resources. Instead, abundances of kit foxes were constrained when coyote abundance reached a threshold. Below this threshold, kit foxes were more common on areas with low shrub cover, possibly due to lack of hiding cover for lagomorph prey that increased their predation risk. Our system included two alternative states: IGP predator dominated and coexistence of IGP predator and prey. Coexistence may have been facilitated by temporal niche partitioning as diel activity patterns differed for coyotes and kit foxes. Future research on intraguild predation should integrate spatial and temporal niches to understand species coexistence including on dynamic landscapes undergoing restoration.}, keywords = {Canis latrans, Chihuahuan Desert, Diel activity, Intraguild predation, shrub encroachment, Valupes microtis}, doi = {10.1016/j.jaridenv.2021.104588}, url = {files/bibliography/21-026.pdf}, author = {Robert L. Schooley and Brandon T Bestelmeyer and John M. Coffman and Casey Wagnon} } @article {JRN55330, title = {Sampling design workflows and tools to support adaptive monitoring and management}, journal = {Rangelands}, year = {2021}, month = {9/30/2021}, pages = {1-9}, abstract = {On the Ground {\textbullet}Adaptive land management requires monitoring of resource conditions, which requires choices about where and when to monitor a landscape. {\textbullet}Designing a sampling design for a monitoring program can be broken down in to eight steps: identifying questions, defining objectives, selecting reporting units, deciding data collection methods, defining the sample frame, selecting an appropriate design type, deciding stratification and allocation, and identifying the required sampling effort. {\textbullet}Here, we provide descriptions of each step in the process and identify tools and resources to complete each step.}, keywords = {data collection, monitoring, monitoring workflow, sample design, spatially balanced sampling, stratification}, doi = {10.1016/j.rala.2021.08.005}, url = {files/bibliography/21-040.pdf}, author = {Nelson Stauffer and Danielle Duni and Jason W. Karl and Travis Nauman} } @article {JRN55346, title = {Size distribution of mineral dust emissions from sparsely vegetated and supply-limited dryland soils}, journal = {Journal of Geophysical Research: Atmospheres}, volume = {126}, year = {2021}, month = {11/08/2022}, pages = {e2021JD035478}, abstract = {Controls on the particle size distribution (PSD) of mineral dust emissions remain poorly understood. Under near-idealized conditions, dust PSDs can appear invariant with wind friction velocity. However, dryland vegetation attenuates surface friction velocities, and soil crusting reduces the supply of loose erodible material and increases surface resistance to abrasion. Under such conditions, variability in saltation bombardment efficiency and intensity could have a large effect on dust PSDs. We present dust emission measurements from vegetated, supply-limited aeolian systems that indicate the dependence of emission-flux PSD on wind friction velocity. We find the fine fraction (<5 μm) of dust particles increases with friction velocity. Results suggest models that assume wind-invariance of the emission-flux PSD may not be generalizable for crusted soils with vegetation. There is a need for dust models to represent variability in emission-flux PSDs for land management, air quality, and climate applications across vegetated and sediment supply-limited drylands.}, keywords = {Mineral Dust Emissions, Size Distribution, soils, Supply-Limited Dryland Soils, Vegetated}, doi = {10.1029/2021JD035478}, url = {files/bibliography/21-055.pdf}, author = {Nicholas Webb and Susan LeGrand and Brad Cooper and Ericha Courtright and Brandon Edwards and Christopher Felt and Justin Van Zee and N. Ziegler} } @article {JRN55237, title = {Scaling up agricultural research with artificial intelligence}, journal = {IEEE IT Professional}, volume = {22}, year = {2020}, pages = {32-38}, type = {05/2020}, chapter = {32}, abstract = {Agricultural systems are enormously variable in space and time. New and developing artificial intelligence (AI)-based tools can leverage site-based science and big data to help farmers and land managers make site-specific decisions. These tools are improving information about soils and vegetation that forms the basis for investments in management actions, provides early warning of pest and disease outbreaks, and facilitates the selection of sustainable cropland management practices. Continued progress with AI will require more observational data across a wide range of agricultural settings, over long time periods.}, issn = {1520-9202}, doi = {10.1109/MITP.2020.2986062}, url = {files/bibliography/20-023.pdf}, author = {Brandon T Bestelmeyer and Marcillo, Guillermo and Sarah McCord and Steven Mirsky and G. E. Moglen and Neven, Lisa and Debra C. Peters and Sohoulande Djebou, Dagbegnon and Wakie, Tewodros} } @article {JRN55204, title = {Social-Ecological Processes and Impacts Affect Individual and Social Well-Being in a Rural Western U.S. Landscape}, journal = {Frontiers in Sustainable Food Systems}, volume = {4}, year = {2020}, month = {04/2020}, abstract = {As many rural landscapes in North America are utilized for agricultural production, research on the variability of land use and land cover trends primarily focuses on social-ecological dynamics and drivers of rural landscape change. Findings from such research improve our understanding of processes that alter landscape structure and function and inform strategies for agro-ecosystem management and conservation. However, to better understand how to conserve agro-ecosystems while balancing the needs of people who live and work across rural landscapes, it is critical to understand what people need to improve and sustain their quality of life and well-being. This necessitates the integration of perspectives, methods, and analytical techniques from scholarship on human dimensions of agro-ecosystems. Research that is designed to connect social-ecological dynamics and landscape change to social impacts and changes to well-being is better situated to inform land management strategies and decision-making for agricultural production policies. Turning to a case study of rural landscapes in southwestern Idaho, we asked livestock producers, public land and resource managers, recreation users, conservationists, and wilderness advocates to describe social-ecological conditions that support and degrade their well-being. Using grounded theory methodology, we analyzed semi-structured interviews to discover meanings of well-being and to understand how people experience changes to their quality of life in an arid rangelands context. Our findings support previous research that suggests well-being is multi-dimensional, while indicating that well-being is experienced at individual and community scales. We discuss our findings in the context of the USDA Agricultural Research Service{\textquoteright}s national network for Long-term Agro-ecosystem Research (LTAR). The LTAR network is charged to identify strategies for sustainable intensification that support agricultural productivity, environmental quality, and rural community prosperity, thus providing opportunity for future research to assess trade-offs to individual and community well-being in response to social-ecological dynamics and land use change.}, doi = {10.3389/fsufs.2020.00038}, url = {bibliography/20-013.pdf}, author = {Amanda Bentley Brymer and David P. Toledo and S. Spiegal and Frederick B. Pierson and Patrick E. Clark and J. D. Wulfhorst} } @article {JRN55265, title = {Snapshot of rancher perspectives on creative cattle management options}, journal = {Rangelands}, year = {2020}, month = {11/2020}, abstract = {A major challenge to successful management of livestock production in the western United States (U.S.) is coping with the extremely variable weather that dramatically affects forage availability. In addition, temperatures have already increased across the western U.S. and will continue to do so, creating even more challenging environmental conditions for future cattle production in the semi-arid and arid west . The Sustainable Southwest Beef project is a new Coordinated Agricultural Project led by New Mexico State University poised to identify viable options for arid lands ranchers and the U.S. beef industry as environmental challenges continue. The 5-year project is being conducted by a diverse team of nearly 30 research, education and extension specialists, focusing on three creative management strategies: precision ranching, heritage breeds and alternative supply chain options. A group of ranchers from the western U.S. advises the team (Figure 1). The Sustainable Southwest Beef team introduced the project to roughly 125 ranchers, feedlot operators and others connected to the beef cattle industry at the 2020 Southwest Beef Symposium in Amarillo, Texas and collected initial rancher perceptions of the three creative management strategies.}, keywords = {Beef production, climate change, Heritage cattle, precipitation, Precision livestock farming, Supply chain}, doi = {https://doi.org/10.1016/j.rala.2020.09.004}, url = {files/bibliography/20-033.pdf}, author = {Emile H. Elias and Skye Aney and G. Duff and Craig Gifford and S. Spiegal and Andr{\'e}s F. Cibils and Jean Steiner and Richard E. Estell} } @proceedings {JRN55190, title = {Spatial prediction of ecosystem state transitions on the Taos Plateau}, volume = {88}, year = {2020}, month = {02/16/2020}, address = {Denver, CO}, abstract = {

Land use, climate, and landscape context jointly determine the occurrence of state transitions in terrestrial ecosystems. State-and- transition models (STM) are used to clarify the roles of drivers, and ecological sites (climoedaphic land units) represent the effects of landscape context. On the Taos Plateau in northern New Mexico, uncertainty about the patterns and drivers of vegetation state transitions impedes sustainable land management. The efficacy of restoration treatments is highly variable, likely due to unrecognized variation in climate and soils. Similar challenges are ubiquitous across terrestrial ecosystems and in particular landscapes with high spatial variability in soils. We used data from federal vegetation monitoring programs and spatial, environmental, and land use data to test for the role of climate, geomorphology, soils, and land use history on restoration success on the Taos Plateau. The large dataset comprises a suite of recently-established core monitoring methods that are consistent across agencies and provide scalable estimates of resource distribution and land change trends across the western U.S. We used a suite of multivariate methods to characterize vegetation states and their relationships to environmental variables to test propositions in conceptual STMs. Preliminary analysis verified the six ecological site concepts which were hypothesized for the study area. Plant functional group abundance and vegetation structure varied within ecological site group based on management history, indicating that multiple vegetation states are present on the landscape and correlated with land use legacies. A workflow for using multivariate analysis of core methods data to inform ecological site and STM concept development is presented for use in other study areas.

}, author = {A. Heller and Nicholas Webb and Brandon T Bestelmeyer and Sarah McCord} } @article {JRN55218, title = {A standardized land capability classification system for land evaluation using mobile phone technology}, journal = {Soil and Water Conservation}, year = {2020}, month = {06/2020}, abstract = {One of the major causes of poverty globally is land degradation and poor natural resource conservation, leading to reduced agricultural productivity. This degradation is often caused by a mismatch between land use and land potential, specifically using marginal lands for agriculture. For over 50 years the Land Capability Classification (LCC) system has been used globally for land evaluation to support soil and natural resource conservation. The LCC system classifies the land into eight classes; however, its use is currently limited by two factors: the lack of digital platforms for data input, storage, and management, and an insufficient technical capacity in many regions necessary to generate the required inputs. This paper describes the development of a system to facilitate rapid, flexible, and transparent determinations of LCC by non-soil scientists using a newly developed function of the Land-Potential Knowledge System (LandPKS) mobile app. Inputs include soil texture and rock fragment volume by depth, slope, and site observations of soil limiting factors. A standardized system for evaluating inputs and calculated indicators was developed based on US and international implementations of LCC. The system was evaluated using USDA Natural Resources Conservation Service soil survey data in eight US counties. Results show that the standardized system predictions were within one class for 73.8\% of the 1,312 soils tested, despite a high level of variability in how LCC was determined within the US database. The LandPKS LCC system was further tested in Tanzania and Ethiopia to examine site-specific applications, usability, and usefulness of the system for national land use planning efforts. It was concluded that the LandPKS app automates a globally applied system (LCC) for supporting natural resource conservation and sustainable land management and can serve as a foundation for crop-specific land suitability evaluations. More generally, improved land evaluation efforts can contribute to better soil and natural resource conservation, more sustainable agricultural systems, and increased food security.}, keywords = {Ethiopia, land capability classification, land evaluation, LandPKS, natural resource conservation, Tanzania}, doi = {https://doi:10.2489/jswc.2020.00023}, url = {files/bibliography/20-027.pdf}, author = {Amy Quandt and Jeffrey E. Herrick and G. Peacock and J. Neff and S. W. Salley and Mkalawa,C. and Buni, Adane} } @inbook {JRN55311, title = {Soil health assessment for agricultural lands}, booktitle = {Approaches to Soil Health Analysis, Volume 1}, volume = {1}, year = {2020}, pages = {79-99}, chapter = {5}, abstract = {There are an increasing number of public and private efforts to evaluate soil health, both here in the USA, and throughout the world. This chapter reviews soil health frameworks that are being widely applied in the US and, in some cases, globally. These include soil health cards. These have been developed in a number of countries and continue to be popular as they rely easily observable indicators. In the US soil health cards were widely developed and distributed by NRCS and universities at the end of the 20th century at state and regional levels. The Soil Condition Index (SCI) was developed by the USDA NRCS to evaluate cropland management systems It predicts the consequences of management actions on the state of soil organic carbon (SOC).The SCI predicts qualitative changes in SOC in the top 10 cm (4 in) of soils based on (1) the amount of organic material, both plant and animal, returned to the soil, (2) number and type of field operations that impact the breakdown and decomposition of organic materials, and (3) the rates of wind and water erosion. The AgroEcosystem Performance Assessment Tool (AEPAT) is a software tool developed to assess relative effects of management on agricultural sustainability, including soil health. The technical reference, {\textquotedblleft}Interpreting Indicators of Rangeland Health{\textquotedblright} (IIRH) incorporates some in-field soil health indicators as does the forest based {\textquotedblleft}Soil Vital Signs: A New Soil Quality Index (SQI) for Assessing Forest Soil Health{\textquotedblright}. IIRH is similar to some of the cropland-focused soil health assessment protocols discussed here in that it requires users to evaluate each indicator against its natural potential, which is a function of climate, topography, and relatively inherent or static soil properties such as texture, depth and mineralogy. A similar approach is used in the Soil Management Assessment Framework (SMAF) which provides site-specific interpretations of soil health indicator results for agriculturally managed lands. It uses measured soil indicator data to assess management impacts on soil function using three steps: indicator selection, indicator interpretation, and if desired integration into an index. The Comprehensive Assessment of Soil Health (CASH) is an assessment tool that relies on mostly laboratory measurements and was originally known as the Cornell Soil Health Test. Finally, the Land-Potential Knowledge System (LandPKS) is a global platform for easily identifying soils and accessing land-related knowledge and information through a mobile app. It includes a module for documenting and monitoring the status of the USDA-NRCS in-field cropland soil health indicators.}, keywords = {agriculturally managed lands, assess management impacts, index, indicator interpretation, indicator selection, integration, measured soil indicator data, site-specific interpretations, soil function, soil health indicator, Soil Management Assessment Framework (SMAF)}, issn = {978-0-891-18980-0}, url = {https://www.wiley.com/en-us/Approaches+to+Soil+Health+Analysis\%2C+Volume+1-p-9780891189800}, author = {Stott, D.E. and Brian Wienhold and Van Es, Harold and Jeffrey E. Herrick} } @article {JRN55231, title = {Scale invariance of albedo-based wind friction velocity}, journal = {Journal of Geophysical Research: Atmospheres}, volume = {125}, year = {2020}, month = {07/26/2020}, pages = {1-15}, abstract = {Obtaining reliable estimates of aerodynamic roughness is necessary to interpret and accurately predict aeolian sediment transport dynamics. However, inherent uncertainties in traditional field measurements and models of surface aerodynamic properties continue to impact basic aeolian research, monitoring, and dust modeling. A new relation between aerodynamic shelter and land surface shadow has been established at the wind tunnel scale, enabling the potential for estimates of wind erosion and dust emission to be obtained from albedo data. Here, we compare estimates of wind friction velocity (u*) derived from traditional methods (wind speed profiles) with those derived from the shadow model at two separate scales using bare soil patch (via net radiometers) and landscape (via MODIS 500 m) datasets. Results show that estimates of~u*~from wind speed profiles are highly variable and therefore uncertain as they change in response to wind speed, direction, turbulence scales, and heterogeneity of the surface roughness. Shadow-based estimates of u* at both scales have small variability because they are integrated over the measurement area and resolve the partition of wind momentum between roughness elements and the soil surface. We demonstrate that the wind tunnel-based relation for predicting wind friction velocities at the soil surface (uS*) is scale invariant. We confirm the need for all wind speed profiles over a rough surface to be corrected for the drag partition if uS* is of interest. In the absence of a reliable drag partition correction in the field, measurements of albedo will reduce uncertainty in field estimates of uS* for wind erosion and dust emission modeling.}, keywords = {aeolian, aerodynamic roughness, Albedo, dust, friction velocity, satellite remote sensing}, doi = {https://doi.org/10.1029/2019JD031978}, url = {files/bibliography/20-028.pdf}, author = {N. Ziegler and Nicholas Webb and A. Chappell and Susan LeGrand} } @article {JRN55160, title = {Synthesis paper: Targeted livestock grazing: Prescription for healthy rangelands}, journal = {Rangeland Ecology and Management}, volume = {72}, year = {2019}, month = {11/01/2019}, abstract = {Targeted livestock grazing is a proven tool for manipulating rangeland vegetation, and current knowledge about targeted livestock grazing is extensive and expanding rapidly.\  Targeted grazing prescriptions optimize the timing, frequency, intensity, and selectivity of grazing (or browsing) in combinations that purposely exert grazing/browsing pressure on specific plant species or portions of the landscape.\  Targeted grazing differs from traditional grazing management in that the goal of targeted grazing is to apply defoliation or trampling to achieve specific vegetation management objectives, whereas the goal of traditional livestock grazing management is generally the production of livestock commodities.\  A shared aim of targeted livestock grazing and traditional grazing management is to sustain healthy soils, flora, fauna, and water resources that, in turn, can sustain natural ecological processes (e.g., nutrient cycle, water cycle, energy flow).\  Targeted grazing prescriptions integrate knowledge of plant ecology, livestock nutrition, and livestock foraging behavior. Livestock can be focused on target areas through fencing, herding, or supplement placement.\  Although practices can be developed to minimize the impact of toxins contained in target plants, the welfare of the animals used in targeted grazing must be a priority.\  Monitoring is needed to determine if targeted grazing is successful and to refine techniques to improve efficacy and efficiency.\  Examples of previous research studies and approaches are presented to highlight the ecological benefits that can be achieved when targeted grazing is applied properly. These cases include ways to suppress invasive plants and ways to enhance wildlife habitat and biodiversity.\  Future research should address the potential to select more adapted and effective livestock for targeted grazing and the associated animal welfare concerns with this practice.\  Targeted livestock grazing provides land managers a viable alternative to mechanical, chemical, and prescribed fire treatments to manipulate rangeland vegetation.}, keywords = {focused grazing, livestock, prescriptive grazing, rangelands, targeted grazing, vegetation manipulation}, doi = {10.1016/j.rama.2019.06.003}, url = {bibliography/19-024.pdf}, author = {C. Donovan Bailey and J. C. Mosley and Richard E. Estell and Andr{\'e}s F. Cibils and M. Horney and John Hendrickson and J.W. Walker and Launchbaugh, K.L. and Burritt, E.A.} } @article {JRN55068, title = {Soil Organic Carbon Erosion is Critical for Land Degradation Neutrality}, journal = {Environmental Science and Policy}, volume = {93}, year = {2019}, month = {03/2019}, pages = {43-52}, chapter = {43}, abstract = {

The Land Degradation-Neutrality (LDN) framework of the United Nations Convention to Combat Desertification (UNCCD) is underpinned by three complementary interactive indicators (metrics: vegetation cover, net primary productivity; NPP and soil organic carbon; SOC) as proxies for change in the land-based natural capital. The LDN framework assumes that SOC changes slowly primarily by decomposition and respiration of CO2 to the atmosphere. However, we show there is growing evidence that SOC erosion also reduces SOC stocks and rapidly after land use / cover change. Here we use a physically-based model to quantify global SOC erosion by wind (2001-2010) and identify global dryland regions where SOC erosion may be a significant problem for achieving LDN. Selected sites in global drylands show SOC erosion accelerating over time. Without targeting and reducing SOC erosion, management practices will fail to sequester SOC and reduce land degradation, thereby undermining the LDN framework. We describe the interrelated nature of the LDN indicators, the importance of including SOC erosion and how land cover can be replaced by erosion that better represents the physical effects of land cover on land degradation processes. Therefore, we call for SOC erosion to become an LDN indicator. Furthermore, our results suggest that fluxes of SOC and soil nutrients by soil erosion should be emphasised in the forthcoming Intergovernmental Panel on Climate Change (IPCC) Special Report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems.

}, keywords = {land cover, land degradation neutrality, sequestration, soil organic carbon, wind erosion}, doi = {doi.org/10.1016/j.envsci.2018.12.020}, url = {files/bibliography/19-009.pdf}, author = {A. Chappell and Nicholas Webb and John Leys and Waters, Cathy and Orgill, Susan and Eyres, Michael} } @article {JRN55003, title = {Stand density and carbon storage in cypress-tupelo wetland forests of the Mississippi River delta}, journal = {Forest Ecology and Management}, volume = {441}, year = {2019}, month = {03/2019}, pages = {106-114}, chapter = {106}, abstract = {

Forested wetlands play a vital role in the coastal zone, but their vulnerability to coastal change{\textemdash}and the impact to high-value ecosystem services{\textemdash}is not as well established as that of more seaward systems such as saltmarsh and mangroves. To address this need, we develop field-based stand density classes, then classify baldcypress-water tupelo (Taxodium distichum (L.) Rich var. distichum; Nyssa aquatica L.) stand density on the Mississippi River delta using a multitemporal ordination of reflectance from Landsat Thematic Mapper imagery. Approximately 29, 50, and 21\% of forest was classified as full canopy, intermediate, and open canopy, respectively. We estimate stand-level live-stem carbon stocks and annual accumulation rates of 96, 67, and 39 t-C ha-1 and 1.9, 1.4 and 0.8 t-C ha-1 yr-1 for full-canopy, intermediate, and open-canopy forest, respectively. Regional live-stem carbon stocks are \~{} 69 t-C ha-1, and total carbon and annual increment for all forest analyzed are \~{}17 Mt-C and \~{}0.34 Mt-C yr-1. Much of the cypress-tupelo forest on the delta stores carbon at rates significantly below the potential of fully stocked stands, yet overall rates of accumulation are comparable to other forest types and coastal systems. Delta-wide, there is a well-defined coastward gradient of stand density, which has important implications for the future of deltaic forests and their ecosystem services. The similarities between forest density gradients and well-documented marsh loss patterns in the region suggest that the same processes driving coastal marsh loss{\textemdash}relative sea level rise exacerbated by human activity{\textemdash}are likely responsible for a second, more gradual interface of land loss at the marsh-forest boundary. Results highlight the potential response of coastal forests to continued environmental change{\textemdash}and associated impacts to the carbon cycle{\textemdash}and provide a baseline for detecting future change to forests on the Mississippi River delta.

}, keywords = {baldcypress, carbon cycle, coastal change, forested wetlands, mississippi river delta, water tupelo}, doi = {doi.org/10.1016/j.foreco.2019.03.046}, url = {files/bibliography/19-005.pdf}, author = {Brandon Edwards and Allen, Scott T. and Braud, Dewitt H. and Keim, Richard F.} } @article {JRN54923, title = {A Strategy for Defining the Reference for Land Health and Degradation Assessments}, journal = {Ecological Indicators}, volume = {97}, year = {2019}, month = {01/2019}, pages = {225-230}, chapter = {225}, abstract = {

Much of the confusion about the definition of reference conditions for land health and degradation assessments is due to differences in policy and management objectives. Selection of a historic reference where it is not necessary, such as in the definition of future land degradation neutrality, can add significant cost and uncertainty to land management projects that require some knowledge of the current status of the land relative to its potential. This paper (1) provides a review of conditions under which historic reference information is and is not required to meet management and policy objectives, (2) summarizes current approaches to defining the reference for land health and degradation assessments, and (3) presents a protocol, {\textquotedblleft}Describing Indicators of Rangeland Health{\textquotedblright} (DIRH) for collecting and organizing data that can be used to define a historic reference. This protocol builds on the framework and indicators presented in the {\textquotedblleft}Interpreting Indicators of Rangeland Health{\textquotedblright} (IIRH). IIRH uses a combination of scientific and local knowledge to generate soil- and climate-specific assessments of three attributes of land health. It is used in a number of countries. In the United States, data are aggregated over 30,000 locations to provide national assessments.

}, keywords = {Baseline, benchmark, indicator, land degradation, land health, rangeland health, Soil health}, doi = {doi.org/10.1016/j.ecolind.2018.06.065}, url = {files/bibliography/19-002.pdf}, author = {Jeffrey E. Herrick and P. L. Shaver and D.A. Pyke and M. Pellant and David P. Toledo and Nika Lepak} } @article {JRN55162, title = {Seeing is not always believing: Crop loss and climate change perceptions among farm advisors}, journal = {Environmental Research Letters}, volume = {14}, year = {2019}, month = {03/26/2019}, abstract = {

As climate change is expected to significantly affect agricultural systems globally, agricultural farm advisors have been increasingly recognized as an important resource in helping farmers address these challenges.\  While there have been many studies exploring the climate change belief and risk perceptions as well as behaviors of both farmers and agricultural farm advisors, there are very few studies that have explored how these perceptions relate to actual climate impacts in agriculture.\  Here we couple survey data from United States Department of Agriculture farm service employees (n=6,514) with historical crop loss data across the United States to explore the relationship of actual climate-related crop losses on farm to farm advisor perceptions of climate change and potential behaviors. Using structural equation modelling we find that among farm advisors that work directly with farms on disaster and crop loss issues, there is a significant positive relationship between crop loss and perceived weather variability changes, while across all farm advisors crop loss is associated with reduced likelihood to believe in anthropogenic climate change. Further, we find that weather variability perceptions are the most consistently and highly correlated with farm advisors\’ perceptions about the need for farm adaptation and future services.\  These results suggest that seeing crop loss does not lead to climate change belief, but may drive weather variability perceptions, which in turn affect farm adaptation perceptions. This lends further evidence to the debate over terminology in climate change communication and outreach, suggesting that weather variability may be the most salient among agricultural advisors.

}, keywords = {agriculture, climate adaptation, farmer, structural equation model, weather variability}, doi = {https://doi.org/10.1088/1748-9326/aafbb6}, url = {files/bibliography/19-023.pdf}, author = {Niles, M. and Wiener, S. and Schattman, R. and Roesch-McNally, G. and J.T. Reyes} } @article {JRN55147, title = {Spatio-temporal variation of crop loss in the United States from 2001 to 2016}, journal = {Environmental Research letters}, volume = {14}, year = {2019}, month = {07/2019}, pages = {1-12}, chapter = {1}, abstract = {

Crop insurance loss data can illuminate variations in agricultural impacts from exposure to weather and climate-driven events, and can improve our understanding of agricultural vulnerabilities. Here we perform a retrospective analysis of weather and climate-driven reasons for crop loss (i.e. cause of loss) obtained from the Risk Management Agency of the United States Department of Agriculture. The federal crop insurance program has insured over $440 billion in liabilities representing farmers{\textquoteright} crops from 2001 to 2016. Specifically, we examine the top ten weather and climate-driven causes of loss from 2001 to 2016 across the nation comprising at least 83\% of total indemnities (i.e. insurance payouts provided to farmers after crop loss events). First, we analyzed the relative fraction of indemnities by causes of loss, over different spatial and temporal resolutions. We found that drought and excess precipitation comprised the largest sources of crop loss across the nation. However, these causes varied strongly over space and time. We applied two additional normalization techniques to indemnities using (1) insurance premia and the gross domestic product implicit price deflator, and (2) liabilities to calculate the loss cost. We conducted trend analyses using the Mann{\textendash}Kendall statistical test on loss cost over time. Differential trends and patterns in loss cost demonstrated the importance of spatio-temporal resolution in assessing causes of loss. The majority of monthly significant trends (p \< 0.05) showed increasing loss cost (i.e. increasing indemnities or decreasing liabilities) in response to weather events. Finally, we briefly discuss an online portal (AgRisk Viewer) to make these data accessible at multiple spatial scales and sub-annual time steps to support both research and outreach efforts promoting adaptation and resilience in agricultural systems.

}, keywords = {adaptation, agriculture, climate change, crop insurance, drought, extreme weather, vulnerability}, doi = {doi.org/10.1088/1748-9326/ab1ac9}, url = {files/bibliography/19-018.pdf}, author = {J.T. Reyes and Emile H. Elias} } @article {JRN55140, title = {Seasonal divergence of landscape use by heritage and conventional cattle on desert rangeland}, journal = {Rangeland Ecology \& Management}, volume = {72}, year = {2019}, month = {07/2019}, pages = {590-601}, chapter = {590}, abstract = {

Adopting livestock with heritage genetics may improve chances for achieving both agriculture and conservation goals on rangelands with harsh, challenging conditions. In the Chihuahuan Desert, preliminary evidence suggests that heritage Raramuri Criollo exploit a greater variety of range resources than conventional cattle. Accordingly, adopting Raramuri Criollo may help sustain vegetation and soils as well as agricultural production. We used GPS collars to track Angus x Hereford and Raramuri Criollo cows in a 1535-ha pasture in southern New Mexico in June - December 2008. As predicted based on past research, home range sizes of Raramuri Criollo exceeded those of Angus x Hereford during seasons with low forage availability - by 31.4 {\textpm} 6.5 ha during Pregreenup and 17.2 {\textpm} 6.5 ha during Drydown - but sizes converged during more productive seasons (Greenup 1, Greenup 2). Angus x Hereford allotted more daily time to resting, with the difference most pronounced during Drydown (71.1 {\textpm} 21.1 min day-1). Angus x Hereford had twice as many hotspots of use (locations with multiple visits of long duration), with seasonal timing and location corresponding with distribution patterns known to impact desirable natural resources. Raramuri Criollo more strongly preferred the Bare/Forbs ecological state and avoided the Shrubland ecological state - with timing that possibly signals an ability to utilize nutritious forbs on open ground despite summer heat. Results are consistent with predictions that compared with conventional cattle, Raramuri Criollo have greater daily mobility and wider spatial distribution during dry seasons. Although not directly measured, results also suggest that the heritage breed has superior heat tolerance and lower impact on desirable natural resources. These findings provide evidence that Raramuri Criollo can support sustainable livestock production in the Chihuahuan Desert, but direct measurements of profitability and environmental effects are needed before adoption can be recommended widely.

}, keywords = {GPS monitoring, grazing distribution, Heritage genetics, phenology, Raramuri Criollo, state-and-transition models}, doi = {10.1016/j.rama.2019.02.008}, url = {files/bibliography/19-015.pdf}, author = {S. Spiegal and Richard E. Estell and Andr{\'e}s F. Cibils and D. K. James and H. Raul Peinetti and Dawn M. Browning and Kirsten B. Romig and Amy L. Gonzalez and Andrew Lyons and Brandon T Bestelmeyer} } @proceedings {JRN55391, title = {Sustainability is in the eye of the stakeholder and other lessons learned through boundary-spanning research on arid rangelands}, year = {2019}, month = {8/8/2019}, abstract = {Arid rangelands have undergone well-documented social and ecological changes over the past century in the United States. Ongoing shrub encroachment, soil erosion, and biodiversity loss have affected a variety of ecosystem services, from forage provision to air quality to hunting and other recreational opportunities. In light of these changes, the USDA Jornada Experimental Range and its partners are investing in three complementary lines of research aimed toward improving sustainability in arid rangelands: a) understanding change in the environment and ecosystem services, b) evaluating strategies to increase income in altered rangelands, and c) identifying the effects of restoration management. Our research program is designed to span outmoded boundaries among scientists, managers, and other community members so that science can effectively inform policy and practice. Through interviews and questionnaires, we are investigating how stakeholders perceive and interact with the landscape, to illuminate how long-term change affects the community and its support for different land management approaches. Concurrently, we are comparing a heritage cattle type (Raramuri Criollo) with breeds used conventionally, in terms of profitability, environmental impacts, and barriers to adoption, on scales ranging from pasture to region to planet. Boundary-spanning cattle research is underway at five ranches across the western U.S., and although the program is relatively young, we have already learned a few key lessons to share with ESA participants focused on workinglands. We have found that structuring experiments within existing agricultural operations is imperative, but doing so can affect the questions that can be reasonably asked. We have also learned that even if evidence is overwhelmingly positive about a particular type of cattle and its probable effects on sustainability outcomes, messaging about results must match data collected (this can be a challenge). Another big lesson is that it is generally a bad idea to proclaim the sustainability virtues of one livestock breed at the expense of another, as both sustainability and livestock virtues differ with the eye of the stakeholder. We will describe how these lessons were learned, discuss some of the risks and rewards of boundary-spanning research, and outline our vision for how such efforts can improve sustainability of agriculture in arid rangelands in the U.S. and worldwide.}, author = {S. Spiegal and Brandon T Bestelmeyer and Andr{\'e}s F. Cibils and Andrew Cox and Bethany Cutts and Maude Dinan and Richard E. Estell and Amy L. Gonzalez and Leticia Lister and Robert Paulin and Matthew Redd and Robert L. Schooley and C. Tolle} } @article {JRN55132, title = {Small mammal herbivory and grassland recovery potential in the Chihuahuan Desert}, journal = {Journal of Arid Environments}, volume = {166}, year = {2019}, month = {07/2019}, pages = {11-16}, chapter = {11}, abstract = {

In many arid ecosystems, shrub encroachment is associated with the loss of valuable perennial grasses. Increased native rodent and lagomorph abundance associated with shrub encroachment can have negative effects on grass persistence and restoration. In the Chihuahuan Desert, herbivore abundance can be up to two times greater in degraded Prosopis glandulosa (honey mesquite) shrublands than in intact Bouteloua eriopoda\ (black grama) grasslands. We tested the\ recovery potential of B. eriopoda\ patches in shrub-dominated, grass-dominated and ecotone (grass and shrub co-dominated) states that were exposed to or protected from native rodent and lagomorph herbivores. Herbivore exclosures and control quadrats\ were established in a replicated blocked\ design.\ A disturbance of 40cm x 40cm was created in the center of a B. eriopoda grass patch\ in each treatment quadrat\ in 2001, whereby all above ground biomass was removed in order to examine the ability of\ B. eriopoda to recolonize disturbed areas. The disturbed areas were measured for recruitment and re-establishment of\ B. eriopoda\ in 2002, 2005 and 2008.\ Although herbivore abundance was greater in shrub-dominated states than the other states for the given time periods, there was little difference in recruitment and re-establishment\ of\ B. eriopoda among\ states and in response to rodent exclusion. Because increased herbivore abundance in shrub-dominated states\ did\ not constrain grass recovery potential, other factors are likely to be more important constraints on perennial grasses recovery in the Chihuahuan Desert.

}, keywords = {Bouteloua eriopoda, Chihuahan Desert, herbivory, perennial grass regeneration, prosopis glandulosa, rodents}, doi = {doi.org/10.1016/j.jaridenv.2019.04.001}, url = {files/bibliography/19-013.pdf}, author = {L.N. Svejcar and Brandon T Bestelmeyer and D. K. James and Debra C. Peters} } @article {JRN54924, title = {Synchronous species responses reveal phenological guilds: implications for management}, journal = {Ecosphere}, volume = {9}, year = {2018}, month = {09/2018}, pages = {1-23}, chapter = {1}, abstract = {

Phenological studies are critical for understanding the ability of terrestrial ecosystems to respond to changes in climate. Monitoring seasonal transitions at the species or community level across large areas is challenging and expensive. One approach for lowering costs is to identify phenological guilds{\textemdash}groups of species that exhibit similar timing of seasonal transitions{\textemdash}and limit monitoring to a smaller number of species within a guild. In this study, we evaluated 23 consecutive years of monthly observations of individual species at 15 long-term study sites at the Jornada Basin USDA-Long-Term Ecological Research site to identify patterns in the onset of three phenophases{\textemdash}leaf-out, flower, and fruit{\textemdash}of 16 widely occurring species in the arid southwestern United States and to investigate the existence of phenological guilds. We conducted univariate analyses of distributions in the timing of leaf, flower, and fruit production across time and space and multivariate cluster analysis of the time series to identify coherent groups of species{\textendash}site instances that exhibit coherence in timing of phenophase onsets (i.e., guilds). The six species of C3 shrubs demonstrated greater consistency in timing of all phenophases relative to C4 grasses. Further, we found that in all species, leaf-out occurred prior to the onset of the summer monsoon rains. Cluster analysis revealed six groups of species{\textendash}site observations demonstrating high within-year concordance in timing of leaf-out and first fruit across variable site conditions and rainfall years. The six groups for timing of first fruit differed from those for first leaf in that they exhibited greater multi-species membership and within-year variability in timing. We propose that use of phenological guilds can improve the efficiency of ecosystem monitoring, predictive models of ecosystem cues driving phenological events, and land management outcomes.

}, keywords = {Chihuahuan Desert, drylands, first fruit, first leaf, long-term ecological research, pattern recognition, phenological functional group, plant phenology, Special Feature: Dynamic Deserts, start of season}, doi = {doi.org/10.1002/ecs2.2395}, url = {files/bibliography/18-017.pdf}, author = {Dawn M. Browning and Theresa Crimmins and D. K. James and S. Spiegal and Matthew Levi and John P. Anderson and Debra C. Peters} } @conference {JRN55060, title = {Significance for dust emission modelling of omitting changing aerodynamic roughness}, booktitle = {International Conference on Aeolian Research}, year = {2018}, month = {06/2018}, address = {Bordeaux, France}, abstract = {

Experiments of dust emission processes have informed the development and evolution of dust emission schemes that underpin global dust emission models (GDEMs) [1, 2]. Despite these improvements, many GDEMs retain only crude approximations of the emission processes because they do not adequately balance upscaling, parameterisation parsimony and process fidelity [3]. The GDEMs focus on static and homogeneous land surface aerodynamic roughness (and soil characteristics, not tackled here). This approach omits the spatio-temporal dynamics of soil surface shear stress due to land use / land management change, CO2-fertilisation and drought amplification. Consequently, observed reduction in dust emission in e.g., the west African Sahel cannot be replicated by GDEMs [4, 5]. The same omission very likely causes modelled wind speed outputs to be much more uncertain than currently recognized. For example, observed wind stilling is absent in modelled wind speed outputs [6]. To establish the significance of these omissions, we improve shear stress dynamics using an albedo-based parameterization of the aerodynamic roughness normalized by wind speed [7]. We use MODIS albedo (MCD43A1 8-daily, 500 m) and GLDAS modelled wind speed data and other global datasets to investigate the spatio-temporal dynamics of global and dust emission. Global drylands show distinct and opposing trends. Modelled winds dominate dust emission inconsistent with trends. Omitting changing aerodynamic roughness in wind data and dust emission will render GDEM outputs ineffective and interpretations unreliable. A solution is to use u_S*/U_f and embed GDEMs in to LSMs coupled to GCMs. Improved modelling of dust emission spatio-temporal dynamics will likely reduce uncertainty in radiative forcing and biogeochemical cycling for climate change projections.

}, author = {A. Chappell and Nicholas Webb} } @article {JRN54904, title = {Soil water dynamics at 15 locations distributed across a desert landscape: insights from a 27-yr dataset}, journal = {Ecosphere}, volume = {9}, year = {2018}, month = {07/2018}, pages = {36 pp}, abstract = {

Desert ecosystems are primarily limited by water availability. Within a climatic regime, topography, soil characteristics, and vegetation are expected to determine how the combined effects of precipitation, temperature, and evaporative demand of the atmosphere shape the spatial and temporal patterns of water within the soil profile and across a landscape. To forecast how desert landscapes may respond to future climatic conditions, it is imperative to improve our understanding of these ecohydrologic processes. Here, we report on 27 yr of monthly soil volumetric water content (VWC) measurements and associated soils data from a site in the northern Chihuahuan Desert of North America. The dataset includes VWC and soil properties measured to 3 m in depth across 15 locations that encompass a range of Chihuahuan Desert vegetation types. We use this unique dataset (1) to generate insights into general temporal and depth patterns in VWC, (2) to analyze how VWC corresponds to measures of climatic conditions, and (3) to qualitatively evaluate the relative importance of soils, topographic setting, and vegetation type in mediating temporal patterns in VWC. Analyses of this unique dataset emphasize the importance of soil and topographic setting in determining depth and temporal patterns in VWC across time. Results emphasize the episodic nature of deep wetting events in our study system{\textemdash}essentially limited to three large events over the 27-yr record driven primarily by wetter than normal winters. Comparison of soil water dynamics between mesquite shrub coppice dunes and interspace soils suggests the {\textquotedblleft}island of fertility{\textquotedblright} concept does not extend to soil water. Median VWC was strongly coupled to climatic conditions over surprisingly long windows at most locations (6{\textendash}18 months), suggesting that soil water at depth is decoupled from short climatic pulses. However, VWC dynamics and VWC{\textendash}climate relationships varied among locations, depths, and seasons, with unexpected similarities in ecohydrologic dynamics observed among very different vegetation types (e.g., an eroded creosote shrubland and a playa grassland). These results further underscore the importance of ecohydrological investigations in these ecosystems, given forecasts for a warmer and more variable climate in deserts globally.

}, keywords = {Chihuahuan Desert, coppice dunes, critical zone, deep recharge, desertification, ecohydrology, grassland, landscape context, neutron moisture meter, shrubland, soil water, Special Feature: Dynamic Deserts, vadose zone}, doi = {e02335. 10.1002/ecs2.2335}, url = {files/bibliography/18-013.pdf}, author = {Danielle Duni and Matthew D. Petrie and Debra C. Peters and John P. Anderson and K. Crossland and Jeffrey E. Herrick} } @conference {JRN54946, title = {Southwest US dust monitoring and mitigation symposium}, booktitle = {73rd Soil and Water Conservation Society International Annual Conference}, year = {2018}, month = {08/2018}, address = {Albuquerque, New Mexico}, abstract = {

We propose a symposium to address dust monitoring and mitigation in semi-arid agricultural settings, with a focus on the Southwest United States. Participants representing NRCS, ARS, the USDA Southwest and Southern Plains Climate Hubs, land-grant universities, and other key partners will discuss various aspects of dust monitoring (e.g., National Wind Erosion Network establishment) and mitigation (e.g., best practices for land management). The impacts of climate variability and change on existing and projected regional dust generation and air quality will provide the foundation for discussion of interdisciplinary and interconnected impacts, such as changes in water availability, soil quality, and management practice implications for long-term sustainability and resilience.\  Presentation of dust mitigation recommendations and an update on a new USDA-sponsored draft dust mitigation handbook, organized by production type, will be followed by audience participation and feedback focused on practicable solutions and discussion of future field research and demonstration projects. Relevant audience recommendations and feedback will be incorporated into the final version of the USDA dust monitoring and mitigation handbook. We propose one 90-minute session wherein a series of presentations (60-minutes) will be followed by presentation and audience feedback and interaction on the USDA dust monitoring and mitigation handbook. The symposium will be moderated by the organizers.

}, author = {Emile H. Elias and David A. Brown and Steve Smarik and Nicholas Webb and David Dubois} } @proceedings {JRN54870, title = {Science with a selfie stick: Plant biomass estimation using smartphone based {\textquoteleft}Structure From Motion{\textquoteright} photogrammetry}, volume = {January 28-February 2, 2018}, year = {2018}, month = {01/28/2018}, publisher = {Society for Range Management Meeting Proceedings}, address = {Sparks, NV}, abstract = {

Significant advancements in photogrammetric Structure-from-Motion (SfM) software, coupled with improvements in the quality and resolution of smartphone cameras, has made it possible to create ultra-fine resolution three-dimensional models of physical objects using an ordinary smartphone. Here we present an open-source modeling framework for creating three-dimensional models of vegetation structure using smartphone video of a user-defined sampling space (e.g., 1 m2). Our main objective was to evaluate the accuracy of our SfM sampling method in predicting above-ground biomass relative to traditional estimation techniques. A series of permanent 1-m2 quadrat sampling sites at the Jornada Experimental Range in southern New Mexico were used to develop the SfM sampling method, with each quadrat differing in its proportions of shrub vs. herbaceous vegetation composition. \ A smartphone mounted on a selfie stick was used to capture video of each 1-m2 quadrat by circumnavigating it while moving the smartphone up and down to capture a range of image angles. Images were extracted from video frames at sampling rate of 4 frames per second and used to create densely reconstructed point clouds using open-source SfM software. Point clouds were georeferenced using a set of 3 control points located on the ends of a 0.25-m3 PVC corner frame placed at each site prior to imaging. Canopy volume was calculated for each point cloud using a foliar canopy approach, and used to model above ground biomass using published linear regression models. These results were compared to traditional nondestructive biomass estimates that were calculated by measuring the dimensions (cover and height) of individual plants or plant parts within each quadrat and converted to aboveground biomass using allometric equations. Preliminary results show a strong correspondence between measured and SfM modeled biomass. Our presentation will describe the details of this method and discuss its potential utility in increasing the accuracy and repeatability of field-based biomass estimation.

}, author = {Jonathan Maynard and Jason W. Karl} } @article {JRN54901, title = {Shrub encroachment, productivity pulses, and core-transient dynamics of Chihuahuan Desert rodents}, journal = {Ecosphere}, volume = {9}, year = {2018}, month = {07/2018}, pages = {Article e02330}, abstract = {

Drylands worldwide are experiencing shrub encroachment into grasslands with potential consequences for biodiversity and ecosystem services. Climate change could increase the rate of shrub encroachment, amplify precipitation variability, and thus alter bottom-up processes for animal communities. Desert rodents are important biodiversity elements of arid grasslands and shrublands that exert strong effects on soil, vegetation, and other animal species. We used long-term data from the Jornada Basin Long Term Ecological Research site in the Chihuahuan Desert of southern New Mexico to ask whether bottomup control of desert rodents changes across shrub encroachment gradients. Our design included spatial blocks with replicated ecological states representing transitions from black grama (Bouteloua eriopoda) to honey mesquite (Prosopis glandulosa). Grassland-to-shrubland transitions did not produce degraded ecosystems, on average, with reduced net primary production or decreased rodent biomass. However, more rodent biomass was supported on unencroached grasslands following droughts whose frequency and severity may increase in southwestern United States. Hence, the observed evenness in rodent biomass across ecological states should be sensitive to climate change. The best predictors of rodent biomass also differed markedly for two trophic groups. This outcome was explained by considering core-transient dynamics. Granivores were mostly core species that regularly occurred on sites and responded to lagged net primary production at local scales, whereas folivores included transient species (especially Sigmodon hispidus) that responded to lagged precipitation at broader scales via spillover dynamics. Bottom-up processes for desert rodents across shrub invasion gradients were understood by integrating lagged responses to productivity pulses with core-transient structuring of communities.

}, keywords = {bottom-up control, Chihuahuan Desert, net primary production, precipitation variability, prosopis glandulosa, rodent communities, shrub encroachment, Special Feature: Dynamic Deserts}, doi = {e02330. 10.1002/ecs2.2330}, url = {files/bibliography/18-009.pdf}, author = {Robert L. Schooley and Brandon T Bestelmeyer and A. Campanella} } @article {JRN54905, title = {On the sensitivity of hillslope runoff and channel transmission losses in arid piedmont slopes}, journal = {Water Resources Research}, volume = {54}, year = {2018}, pages = {4498-4518}, abstract = {

Channel transmission losses alter the streamflow response of arid and semiarid watersheds and promote focused groundwater recharge. This process has been primarily studied in dryland channels draining large areas that are displaced away from hillslope runoff generation. In contrast, small watersheds on arid piedmont slopes allow the investigation of interactive hillslope and channel processes that control the partitioning between surface and subsurface flows. In this study, we utilize high-resolution, long-term measurements of water balance components in an instrumented watershed of the Chihuahuan Desert to set up, parameterize, and test a process-based, distributed hydrologic model modified to account for channel losses. A transient method for capturing capillary effects in channels results in simulations with a reliable representation of the watershed energy balance, soil moisture dynamics, hillslope infiltration, channel transmission (or percolation) losses, and streamflow yield over the study period. The simulation also reproduces a conceptual model of hillslope infiltration-excess runoff generation linked to downstream channel percolation losses that depend on the rainfall event size. Model-derived thresholds were obtained for the amount of hillslope runoff (6 mm) and rainfall (12.5 mm) necessary for streamflow yield, such that 40\% of percolation occurs for small events that do not reach the outlet. Using a set of scenarios, we identify that hillslope infiltration controls the rainfall threshold necessary to initiate percolation, while channel infiltration affects the partitioning into percolation and streamflow yield. Thus, the connectivity along hillslope-channel pathways is deemed an essential control on the streamflow generation and groundwater recharge in arid regions with complex terrain.

}, keywords = {channel transmission losses, Chihuahuan Desert, groundwater recharge, hillslope infiltration, hydrologic model, hydrology, percolation losses, piedmont slopes, runoff, soil moisture dynamics, streamflow yield, water balance}, doi = {10.1029/2018WR022842}, url = {files/bibliography/JRN54905.pdf}, author = {A. P. Schreiner-McGraw and Enrique Vivoni} } @inbook {JRN54699, title = {State and transition models: Theory, applications, and challenges. In: Briske, D.D. Rangeland Systems: Processes, Management and Challenges}, booktitle = {Springer Series on Environmental Management}, year = {2017}, pages = {303-345}, publisher = {Rangeland Systems}, organization = {Rangeland Systems}, chapter = {9}, address = {Gewerbestrasee, Switzerland}, abstract = {

State and transition models (STMs) are used for communicating about ecosystem change in rangelands and other ecosystems, especially the implications for management. The fundamental premise that rangelands can exhibit multiple states is now widely accepted. The current application of STMs for management, however, has been limited by both the science and the ability of institutions to develop and use STMs. In this chapter, we provide a comprehensive and contemporary overview of STM concepts and applications at a global level. We first review in detail the ecological concepts underlying STMs with the goal of bridging STMs to the recent theoretical developments and debates in ecology. We then provide a synthesis of the history of STM development and current applications in rangelands of Australia, Argentina, the United States, and Mongolia, exploring why STMs have been limited in their application for management. Key challenges in the use of STMs for management are addressed and recent advances that may improve STMs, including participatory approaches in model development, the use of STMs within a structured decision-making process, and mapping of ecological states are described. We conclude a summary of actions that could increase the utility of STMs for collaborative adaptive management in the face of global change.

}, doi = {10.1007/978-3-319-46709-2_9}, url = {files/bibliography/17-010.pdf}, author = {Brandon T Bestelmeyer and A.J. Ash and Joel R. Brown and Densambuu, M. and Maria Fern{\'a}ndez-Gim{\'e}nez and Jane M. F. Johnson and Matthew Levi and Dardo Rub{\'e}n L{\'o}pez and Rumpff, L. and H. Raul Peinetti and P. L. Shaver} } @conference {JRN54779, title = {Supporting tribal agriculture and natural resources in a changing climate working group}, booktitle = {National Adaptation Forum}, year = {2017}, month = {05/2017}, publisher = {National Adaptation Forum}, organization = {National Adaptation Forum}, address = {St. Paul, MN}, abstract = {

The U.S. Department of Agriculture (USDA) Climate Hubs were created in 2014 to deliver science-based, region-specific information and technologies to enable climate-informed decision-making. Our stakeholders include agricultural and natural resource managers (i.e. farmers, ranchers, forest land managers), USDA agencies, and cooperative extension among others. The Climate Hubs have a unique opportunity to facilitate dialogue on challenges to implementing USDA programs for conservation or technical assistance in tribal communities. Conversely, it is also important to share examples of adaptation projects that have been successful at navigating USDA and other federal programs.
The overarching objective of this working group is to build partnerships and collaborations among land management organizations (including USDA), cooperative extension, academic/research community, and Tribal members to effectively manage Native American agricultural and natural resources in a changing climate. Specifically, we invite various officials from the following land management agencies that work with Tribal communities: (1) USDA: Agricultural Research Service (ARS), Farm Service Agency (FSA), Natural Resources Conservation Service (NRCS), Rural Development (RD), U.S. Forest Service (USFS); and (2) Department of Interior: Bureau of Indian Affairs (BIA), Bureau of Land Management (BLM). We invite participants from around the country to compare and contrast stakeholder engagement and projects by geographic region. Ultimately, we hope that the constructive sharing of experiences improves how USDA programs collaboratively supports Tribal agriculture in a changing climate.

}, author = {Reeves, Matt and Helena Deswood and Kelley, Windy and Lane, Erin and Novak, Rachael and Dannele E. Peck and Schmitt, Kristen and Wiener, John} } @conference {JRN54815, title = {Sustainable intensification of U.S. agriculture: Aspirations, barriers, and the role of the LTAR network}, booktitle = {ASA-CSSA-SSSA Annual Meeting}, year = {2017}, month = {10/2017}, publisher = {ASA-CSSA-SSSA Annual Meeting Abstracts}, organization = {ASA-CSSA-SSSA Annual Meeting Abstracts}, address = {Tampa, FL}, abstract = {

Sustainable intensification of agriculture in the United States will require profound shifts in land management, consumer markets, and public policies. The Long-Term Agroecosystem Research (LTAR) network was established to facilitate these shifts. Using a common experiment, network sites in 18 biogeographically diverse regions are comparing {\textquotedblleft}business-as-usual{\textquotedblright} with {\textquotedblleft}aspirational{\textquotedblright} production systems that represent options for local sustainable intensification. We used a conceptual model described in a companion talk to elucidate common themes across the regions represented by LTAR. We found that all sites share concerns about business-as-usual production, including the economic and environmental costs of agricultural intensification and specialization, tendencies toward uniform management despite varying soil and rainfall conditions, and mounting environmental change. Though specifics differ among regions, LTAR{\textquoteright}s aspirational production systems reveal four general strategies for sustainable intensification: 1) ecological intensification, 2) matching management strategies with land potential and climatic conditions, 3) mitigating and enhancing resilience to environmental changes, and 4) managing agricultural lands with a landscape perspective. Fifteen field- and enterprise-level practices are under evaluation to advance these four strategies, yet adoption of the practices lags behind outreach in all LTAR regions. Economic, informational, and social factors are ongoing barriers to widespread adoption. Overcoming these barriers will require financial mechanisms that make aspirational production more profitable, better understanding of the trade-offs between profitability and environmental quality, and long-term partnerships among producers, agroecologists, and social scientists.

}, author = {S. Spiegal and Brandon T Bestelmeyer} } @conference {JRN54631, title = {A spatial dynamic framework for landscape-scale assessment of accelerated wind erosion in Australian rangelands}, booktitle = {9th International Conference on Aeolian Research}, year = {2016}, month = {07/2016}, publisher = {International Conference on Aeolian Research}, organization = {International Conference on Aeolian Research}, address = {Mildura, Australia}, abstract = {
An estimated 110 Mt of dust is eroded by wind from the Australian land surface each year, most of which originates from the arid and semi-arid areas. Livestock production is a major activity in these areas and can increase their susceptibility to wind erosion by further reducing vegetation cover and modifying surface soil stability. While accelerated wind erosion is widely accepted to exist, the scale of grazing impacts in rangelands is still largely debated, because pastoral land management activities have received less research attention than cultivated land management. To date, most methods used to assess the impacts of pastoral activities on wind erosion have been made limited progress in discriminating accelerated wind erosion, due to: 1) their broad spatial and/or temporal resolutions and 2) the scarcity of data on the effects of spatial and temporal variations of land management impacts on land erodibility. In addition, the outcomes of these broad scale studies have seldom been translated into recommendations that are relevant for land managers. \ Here, we present a framework developed to assess accelerated wind erosion at landscape scale. The framework combines soil erodibility, vegetation and grazing intensity data in a Geographical Information System to quantify land erodibility and accelerated erosion risk on different land types. Land erodibility is defined using process-based relationships, integrating vegetation cover and erodible soil fraction. Grazing intensity is determined by the distance from the livestock watering points. For every time period, the land erodibility of a landscape is compared to a reference time period, when erodibility was primarily influenced by climate conditions. Accelerated wind erosion risk maps are produced for each land type. \ We apply the framework to multiple land types in rangelands of western Queensland in Australia. Our results show that the risk of accelerated erosion is much greater during drier periods than in wetter periods. Up to 84\% of the landscape evidenced accelerated erosion in dryer periods, whereas in wetter periods less than 10\% of the landscape displayed some level of accelerated erosion. Overall, the grazing gradient-wind erosion framework produces encouraging results; overcoming three limitations of previous methods for assessing accelerated erosion, by: 1) accounting for spatio-temporal variations of land management, 2) integrating a soil erodibility component which includes the effect of trampling, and 3) operating at a landscape scale to increase its functionality for land managers.
}, author = {Aubault, Helene and Nicholas Webb and Craig Strong and Grant McTainish} } @conference {JRN54635, title = {A spatial dynamic framework for landscape-scale assessment of accelerated wind erosion in Australian rangelands}, booktitle = {9th International Conference on Aeolian Research}, year = {2016}, month = {07/2016}, publisher = {International Conference on Aeolian Research}, organization = {International Conference on Aeolian Research}, address = {Mildura, Australia}, abstract = {
An estimated 110 Mt of dust is eroded by wind from the Australian land surface each year, most of which originates from the arid and semi-arid areas. Livestock production is a major activity in these areas and can increase their susceptibility to wind erosion by further reducing vegetation cover and modifying surface soil stability. While accelerated wind erosion is widely accepted to exist, the scale of grazing impacts in rangelands is still largely debated, because pastoral land management activities have received less research attention than cultivated land management. To date, most methods used to assess the impacts of pastoral activities on wind erosion have been made limited progress in discriminating accelerated wind erosion, due to: 1) their broad spatial and/or temporal resolutions and 2) the scarcity of data on the effects of spatial and temporal variations of land management impacts on land erodibility. In addition, the outcomes of these broad scale studies have seldom been translated into recommendations that are relevant for land managers.\ 
Here, we present a framework developed to assess accelerated wind erosion at landscape scale. The framework combines soil erodibility, vegetation and grazing intensity data in a Geographical Information System to quantify land erodibility and accelerated erosion risk on different land types. Land erodibility is defined using process-based relationships, integrating vegetation cover and erodible soil fraction. Grazing intensity is determined by the distance from the livestock watering points. For every time period, the land erodibility of a landscape is compared to a reference time period, when erodibility was primarily influenced by climate conditions. Accelerated wind erosion risk maps are produced for each land type.\ 
We apply the framework to multiple land types in rangelands of western Queensland in Australia. Our results show that the risk of accelerated erosion is much greater during drier periods than in wetter periods. Up to 84\% of the landscape evidenced accelerated erosion in dryer periods, whereas in wetter periods less than 10\% of the landscape displayed some level of accelerated erosion. Overall, the grazing gradient-wind erosion framework produces encouraging results; overcoming three limitations of previous methods for assessing accelerated erosion, by: 1) accounting for spatio-temporal variations of land management, 2) integrating a soil erodibility component which includes the effect of trampling, and 3) operating at a landscape scale to increase its functionality for land managers.
}, author = {Aubault, Helene and Nicholas Webb and Craig Strong and Grant McTainish} } @conference {JRN54614, title = {Stakeholder Theory and Rangeland Management: The Importance of Ranch Income Dependence}, booktitle = {American Geophysical Union Fall Meeting}, year = {2016}, month = {12/2016}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {San Francisco, CA}, abstract = {
The California drought beginning in 2012 has been driven by reduced precipitation and record high temperatures. Hydrologic drought in the Southwest United States is projected to become the new climatology of the region. While ranchers are considered naturally adaptive, often adeptly altering management based upon conditions, the projected increased aridity may challenge rangeland management. Certain rancher characteristics are likely to impact how well ranchers adapt. Based on Stakeholder Theory (ST), we hypothesize that the extent to which ranchers are dependent on their ranches as a source of income would serve as a predictor of several key variables related to ranching adaptation and success. Data were obtained from 507 ranchers throughout the State of California via the Rangeland Decision-Making Survey implemented by University of California, Davis in 2010, just prior to the unprecedented California drought. Consistent with the ST urgency facet, results of linear regression analyses indicate the more dependent ranchers are on their ranches for their income, the more aware they are of USDA ranching initiatives ({\textquoteright} = .19, p \< .001) and state ranching initiatives ({\textquoteright} = .10, p \< .05). In addition, more dependent ranchers are more likely to use multiple and diverse sources of information about ranching ({\textquoteright} = .18, p \< .001), are more likely to realize the severity and extent of the most recent drought{\textquoteright}s impacts ({\textquoteright} = .18, p \< .001), and were more likely to have a drought management plan in place during the most recent drought ({\textquoteright} = .18, p \< .001). These findings are important in relation to both outreach/extension efforts and rangeland research. Outreach/extension efforts should take into account that people less dependent on their ranches are less aware of resources, as well as, less prepared to adapt to drought. Researchers should control for the extent to which ranchers are dependent on their ranches for income in order to ensure more accurate findings.
}, author = {Elias, Steven and Roche, Leslie and Emile H. Elias} } @article {JRN54582, title = {Summary for policymakers: Unlocking the sustainable potential of land resources. Evaluation systems, strategies and tools}, number = {DT/2002/PA}, year = {2016}, month = {06/2016}, pages = {27 pp}, institution = {United Nations Environment Program (UNEP)}, abstract = {

Land evaluation can be used by national policymakers, international development organizations, farmers, and conservationists to increase productivity, biodiversity conservation success, and to promote innovation. Land evaluation helps make better decisions about how to use the land, and is therefore essential to achieving Land Degradation Neutrality (Sustainable Development Goal 15.3). An understanding of the longterm land potential is needed to (a) determine where production can be sustainably increased, and (b) identify land that could be restored.\  Matching land use with its potential allows the inherent long-term potential to be sustainably realized.\  Sustainability depends on (1) potential degradation resistance, and (2) potential resilience, which is the capacity to recover from degradation. Land with similar potential should therefore respond similarly to management.\  Policymakers, development organizations, and land managers, including farmers and conservationists, can use land evaluation to (a) increase productivity while adapting to climate change, (b) minimize social, economic, and environmental risks of land use change, (c) increase restoration and biodiversity conservation success, and (d) promote innovation and knowledge sharing.

}, issn = {DTI/2002/PA}, url = {/files/bibliography/16-013.pdf}, author = {Jeffrey E. Herrick and Arnalds, O. and Brandon T Bestelmeyer and Brignezu, S. and G. Han and Mari-Vaughn V. Johnson and Lu, Y. and Montanarella, L. and Pengue, W. and Toth, G.} } @conference {JRN54521, title = {Spatial probability models of fire in the desert grasslands of the southwestern USA}, booktitle = {6th Natural History of the Gila Symposium}, year = {2016}, month = {02/2016}, address = {Silver City, NM}, abstract = {

Fire is an important driver of ecological processes in semiarid environments; however, the role of fire in desert grasslands of the Southwestern US is controversial and the regional fire distribution is largely unknown. We characterized the spatial distribution of fire in the desert grassland region of the southwestern United States, which includes a large portion of the Upper Gila River watershed. Our objective was to investigate the influence of soil properties and ecological site groups compared to other commonly used biophysical variables for modeling fire probability. Soil-landscape properties significantly influenced the spatial distribution of fire ignitions. Bottomland ecological sites (i.e., soil-landscape classes) experienced more fires than expected in contrast to those with coarse soil textures and high rock fragment content that experienced fewer fire ignitions than expected. Influences of mean annual precipitation, distance to road/rail, soil available water holding capacity (AWHC) and topographic variables varied between ecoregions and political jurisdictions and by fire season. AWHC explained more variability of fire ignitions in the Madrean Archipelago compared to the Chihuahuan Desert. Understanding the spatiotemporal distribution of recent fires in desert grasslands is needed to manage fire and predict responses to changing climate.

}, author = {Matthew Levi and Brandon T Bestelmeyer} } @article {JRN54596, title = {Sunlight and Soil{\textendash}Litter Mixing: Drivers of Litter Decomposition in Drylands}, journal = {Progress in Botany}, volume = {76}, year = {2015}, pages = {273-302}, abstract = {

Decomposition of leaf litter is a key component of biogeochemical cycles but the mechanisms driving it in arid and semiarid ecosystems (drylands) remain unresolved. Here, we review recent findings that demonstrate dual roles of solar radiation (ultraviolet and photosynthetically active radiation) and soil{\textendash}litter mixing as drivers of decomposition in drylands. We focus on the known and potential mechanisms by which these factors influence leaf litter decomposition, explore how the importance of these two drivers may shift over time, and propose possible avenues by which these factors may interact. Special attention is given to UV in sunlight, as this radiation is known to have multiple roles in influencing decomposition and has received considerable recent research attention. We also identify important uncertainties and challenges and offer a generalized conceptual model to guide future research aimed at enhancing our mechanistic understanding and quantitative modeling of the processes by which soil deposition and solar radiation together influence leaf litter decomposition rates in globally extensive dryland ecosystems.

}, keywords = {abiotic mass loss, litter decomposition, photodegradation}, doi = {10.1007/978-3-319-08807-5_11}, url = {files/bibliography/JRN54596.pdf}, author = {Barnes, Paul W. and Heather L. Throop and Steven R. Archer and David D. Breshears and McCulley, Rebecca L. and Tobler, Mark A.} } @conference {JRN54438, title = {Spatial scaling concepts as applied to the assessment and restoration of drylands}, booktitle = {9th US IALE (Interantional Association of Landscape Ecology) World Congress}, year = {2015}, month = {07/2015}, address = {Portland, OR}, abstract = {

Scaling concepts are important because they induce people to think about processes and relationships that might otherwise be overlooked. For land management-related activities, the challenge is to incorporate scaling concepts into routine observation, evaluation, and planning. Drawing on experiences trying to incorporate ecological science into land management planning in drylands, I suggest that three basic scaling principles are becoming common knowledge (and sometimes conventional wisdom). 1) {\textquoteleft}The whole is greater than the sum of its parts{\textquoteright}: The arrangement of distinct land areas within a patch or landscape mosaic can produce emergent properties as a consequence of spatial interactions among adjacent land areas. 2) {\textquoteleft}Location matters{\textquoteright}: Spatial context provided by the landscape can influence the properties of specific locations. 3) {\textquoteleft}How (not to) lie with maps{\textquoteright}: the results of analyses conducted using geographic information systems software depend on the rules by which the map was produced and how the mapped units are interpreted. I will illustrate the importance of these principles for dryland management using examples and discuss how we might better incorporate the principles into routine management activities.\  Abstract $\#$ S33.

}, author = {Brandon T Bestelmeyer} } @article {JRN54393, title = {Strategies to alleviate poverty and grassland degradation in Inner Mongolia: Intensification vs production efficiency of livestock}, journal = {Journal of Environmental Management}, volume = {152}, year = {2015}, month = {04/2015}, pages = {177-182}, chapter = {177}, abstract = {

Semi-nomadic pastoralism was replaced by sedentary pastoralism in Inner Mongolia during the 1960{\textquoteright}s in response to changes in land use policy and increasing human population. Large increases in numbers of livestock and pastoralist households (11- and 9-fold, respectively) during the past 60 yrs have variously degraded the majority of grasslands in Inner Mongolia (78 M ha) and jeopardize the livelihoods of 24 M human inhabitants. A prevailing strategy for alleviating poverty and grassland degradation emphasizes intensification of livestock production systems to maintain both pastoral livelihoods and large livestock numbers. We consider this strategy unsustainable because maximization of livestock revenue incurs high supplemental feed costs, marginalizes net household income, and promotes larger flock sizes to create a positive feedback loop driving grassland degradation. We offer an alternative strategy that increases both livestock production efficiency and net pastoral income by marketing high quality animal products to an increasing affluent Chinese economy while simultaneously reducing livestock impacts on grasslands. We further caution that this strategy be designed and assessed within a social-ecological framework capable of coordinating market expansion for livestock products, sustainable livestock carrying capacities, modified pastoral perceptions of success, and incentives for ecosystem services to interrupt the positive feedback loop that exists between subsistence pastoralism and grassland degradation in Inner Mongolia.

}, keywords = {Pastoral livelihoods, Pastoralism, Poverty trap, Social-ecolgoical systems, sustainability}, doi = {10.1016/j.jenvman.2014.07.036}, url = {/files/bibliography/15-017.pdf}, author = {D.D. Briske and Mengli Zhao and G. Han and Ziu, Changbai and Kemp, David and Kris Havstad and Walter Willms and Kang, Le and Zhongwu Wang and Jianguo Wu and Han, Xingguo and Bai, Yongfei} } @article {JRN54585, title = {Southwest regional climate hub and California subsidiary hub assessment of climate change vulnerability and adaptation and mitigation strategies}, year = {2015}, pages = {76 pp.}, publisher = {United States Department of Agriculture}, abstract = {

This report describes the potential vulnerability of specialty crops, field crops, forests, and animal agriculture to climate-driven environmental changes. Here, vulnerability is defined as a function of exposure to climate change effects, sensitivity to these effects, and adaptive capacity. The exposure of specific sectors of the agricultural and forestry industries varies across the region because the Southwest is climatically and topographically diverse. There is also variability in the sensitivity of different systems to the impacts of climate change. Most significantly, there is potential within agricultural and forestry systems to adjust to climate-related impacts either through inherent resilience or through conservative management practices. The purpose of this analysis is to describe regional vulnerabilities to climate change and adaptive actions that can be employed to maintain productivity of working lands in the coming decades.

}, url = {/files/bibliography/15-029.pdf}, author = {Emile H. Elias and Caitriana Steele and Kris Havstad and Kerri Steenwerth and Chambers, Jeanne and Helena Deswood and A. Rango and Kerr, Amber and Schwartz, Mark and Stine, Peter and Rachel Steele} } @article {JRN54395, title = {Sage-grouse habitat assessment framework: multi-scale habitat assessment tool}, volume = {Technical Reference 6710-1}, year = {2015}, publisher = {Bureau of Land Management and Western Association of Fish and Wildlife Agencies}, abstract = {

This document provides policymakers, resource managers, and specialists with a comprehensive framework for assessing sage-grouse habitat in the sagebrush ecosystem.\  Four pillars form the foundation for the success of this approach:\  science, effective conservation policy, implementation, and adaptive management.\  Recent landscape evaluations indicate that conservation of sagebrush ecosystems has not been realized because large-scale mapping was not available to inform site-scale management actions.\  Advances in landscape ecology enable conservation planners to develop spatially explicit decision support tools that link populations with habitats for effective conservation planning, implementation, and evaluation at landscape scales.\  A shift from local to landscape conservation will empower decision makers to maximize the likelihood of achieving conservation by implementing site-scale actions within priority landscapes.\  Standardized methodologies provide consistency in terminology and techniques for site-scale assessments.

}, author = {Silver, S.J. and Rinkes, E. Thomas and David Nauble and Makela, Paul and Nance, Danelle and Jason W. Karl} } @article {JRN54151, title = {Scale-dependent feedbacks between patch size and plant reproduction in desert grassland}, journal = {Ecosystems}, volume = {18}, year = {2015}, month = {01/2015}, pages = {146-153}, chapter = {146}, abstract = {

Theoretical models suggest that scale-dependent feedbacks between plant reproductive success and plant patch size govern transitions from highly to sparsely vegetated states in drylands, yet there is scant empirical evidence for these mechanisms. Scale-dependent feedback models suggest that an optimal patch size exists for growth and reproduction of plants and that a threshold patch organization exists below which positive feedbacks between vegetation and resources can break down, leading to critical transitions. We examined the relationship between patch size and plant reproduction using an experiment in a Chihuahuan Desert grassland. We tested the hypothesis that reproductive effort and success of a dominant grass (Bouteloua eriopoda) would vary predictably with patch size. We found that focal plants in medium-sized patches featured higher rates of grass reproductive success than when plants occupied either large patch interiors or small patches. These patterns support the existence of scale-dependent feedbacks in Chihuahuan Desert grasslands and indicate an optimal patch size for reproductive effort and success in B. eriopoda. We discuss the implications of these results for detecting ecological thresholds in desert grasslands.

}, keywords = {Bouteloua eriopoda, Chihuahuan Desert, critical threshold, desertification, dryland, feedbacks, patch size, resilience, state transition}, doi = {10.1007/s10021-014-9818-9}, url = {/files/bibliography/15-008.pdf}, author = {L.N. Svejcar and Brandon T Bestelmeyer and Danielle Duni and D. K. James} } @conference {JRN54435, title = {Simulated distribution of an invasive grass, Lehmann lovegrass, in the Chihuahuan Desert under future climate scenarios}, booktitle = {100th Annual Meeting of the Ecological Society of America}, year = {2015}, month = {08/2015}, address = {Baltimore, MD}, abstract = {

ackground/Question/Methods Lehmann lovegrass (Eragrostis lehmanniana), a perennial grass introduced to the Southwest US in the 1930s from South Africa, has had a limited distribution in the Chihuahuan Desert while it has dominated many grassland sites in the Sonoran Desert.\  Previous observational studies and our site-based model simulations suggest that climate (precipitation and temperature) is the main driver for the difference in the current species{\textquoteright} distributions in the two Southwest deserts.\  Our goal was to predict the distribution of Lehmann lovegrass throughout the Chihuahuan Desert under current climate conditions and future climate scenarios.\  We used the SOILWAT simulation model to simulate Lehman lovegrass seedling establishment, with SSURGO data as input for soil related variables.\  The 1971-2000 mean precipitation and temperature from PRISM were used for the current climate conditions, and these data were adjusted based on the projected changes in National Climate Assessment for Southwest US to simulate future climate scenarios.

Results/Conclusions
Under current climatic conditions, the simulated distribution of Lehmann lovegrass in the Chihuahuan Desert is mainly in the southern portion of the desert, similar to observed populations. Under future climate scenarios, the spatial distribution of the species varies due to the combined effects of precipitation and temperature. The species distribution decreases when precipitation decreases or temperature increases a large amount. The species distribution expands when precipitation increases and temperature increases in low to moderate amounts. Our study shows that the distribution of Lehmann lovegrass in the Chihuahuan Desert will depend on the amount and direction of changes in future temperature and precipitation. This uncertainty in the projected distribution adds one more challenge to land management of this invasive grass under climate change.\  Abstract No. PS 18-177.

}, author = {Jin Yao and Debra C. Peters} } @article {JRN53992, title = {Stock density managed in real-time}, volume = {10}, year = {2014}, month = {2014}, pages = {15}, abstract = {

The spatio-temporal management of stocking density will be possible once virtual fencing (VF) becomes a commercial reality.\  VF uses sensory cues (currently audio and electrical stimulation) to change an instrumented animal\&$\#$39;s forward direction of movement.\  Free-ranging cattle instrumented with VF electronics wear hardware that identifies where on the landscape the animal is located, most frequently using the Global Positioning System (GPS).\ \  In addition, Geographic Information System (GIS) hardware and software, also born by the instrumented animal, can be programmed to identify the location of a polygon (paddock) on the landscape. When an instrumented animal attempts to penetrate the polygon\&$\#$39;s perimeter audio and or electrical stimulation cues are administered autonomously to the animal\&$\#$39;s head or neck region to change its forward direction of movement. By ramping the cues from least to most irritating each animal customizes the lowest level of irritation it requires to change its behavior.\  To date research has yet to determine what percent of a herd needs to be instrumented for acceptable control in all landscapes, seasons and with all breeds of animals or how best to generate and store power to keep the animal born electronics functioning for extended periods of time without human intervention.\  Though conventional fencing will never be completely replaced, VF has the potential for holding as well as moving animals over a landscape in real-time.

}, author = {D.M. Anderson} } @article {JRN53910, title = {Savory{\textquoteright}s unsubstantiated claims should not be confused with multipaddock grazing}, journal = {Rangelands}, volume = {36}, year = {2014}, month = {02/2014}, pages = {39-42}, type = {Letter to the Editor}, chapter = {39}, abstract = {

Letters to the Editor: The sole objective of our critique of Mr Savory{\textquoteright}s TED video published in Rangelands1 was to {\textquotedblleft}fact check{\textquotedblright} a portion of the extraordinary claims that he had made relative to sciencebased information. It is incumbent upon a professional discipline to evaluate the relevant evidence and potential viability of proposed management strategies and policies. Regrettably, Richard Teague{\textquoteright}s response does not address any of Mr Savory{\textquoteright}s claims that we addressed in our critique{\textemdash}not all global rangelands are degraded, rangelands have a limited capacity to store carbon, and intensive rotational grazing is not necessary to prevent rangelands from degrading. Here we reiterate these last two points of our initial critique, then address the concerns presented by Teague, and conclude with comments regarding the future direction of grazing systems research.

}, keywords = {climate change, desertification, planned grazing, Savory Method}, doi = {10.2111/1551-501X-36.1.39 }, url = {/files/bibliography/14-008.pdf}, author = {D.D. Briske and Brandon T Bestelmeyer and Joel R. Brown} } @article {JRN54096, title = {Spatial patterns of grassland-shrubland state transitions: a 74-year record on grazed and protected areas}, journal = {Ecological}, volume = {24}, year = {2014}, month = {09/2014}, pages = {1421-1433}, chapter = {1421}, abstract = {

Tree and shrub abundance has increased in many grasslands, causing changes in ecosystem carbon and nitrogen pools that are related to patterns of woody plant distribution. However, with regard to spatial patterns, little is known about (i) how they develop; (ii) how they are influenced by grazing; or (iii) the extent to which intraspecific interactions dictate them. We addressed these questions by quantifying changes in the spatial distribution of Prosopis velutina (mesquite) shrubs over 74 years on grazed and protected grasslands. Livestock are effective agents of mesquite dispersal and mesquite has lateral roots extending well beyond its canopy. We therefore hypothesized that mesquite distributions would be (a) random on grazed areas and clustered on protected areas; and (b) that clustered or random distributions at early stages of encroachment would give way to regular distributions as stands matured and density-dependent interactions intensified. Assessments in 1932, 1948 and 2006 supported the first hypothesis, but we found no support for the second. In fact, clustering intensified with time on the protected area and the pattern remained random on the grazed site. Although shrub density increased on both areas between 1932 and 2006, we saw no progression toward a regular distribution indicative of density-dependent interactions. We propose that processes related to seed dispersal, grass-shrub seedling interactions, and hydrological constraints on shrub size interact to determine vegetation structure in grassland-to-shrubland state changes with implications for ecosystem function and management.

}, keywords = {LISA, livestock exclusion, mesquite, Moran{\textquoteright}s I, pair correlation function, point pattern analysis, Prosopis velutine, Ripley{\textquoteright}s K, Sonoran Desert, spatial autocorrelation, spatial ecology}, url = {/files/bibliography/14-029.pdf}, author = {Dawn M. Browning and Janet Franklin and Steven R. Archer and Jeffrey K. Gillan and Guertin, D. Phillip} } @conference {JRN54398, title = {Simulated impact of climate change on hydrology of multiple watersheds using traditional and recommended snowmelt runoff model methodology}, booktitle = {American Geophysical Union Fall Meeting 2014}, year = {2014}, month = {12/2014}, publisher = {AGU}, organization = {AGU}, address = {San Francisco, CA}, abstract = {

For more than three decades, researchers have utilized the Snowmelt Runoff Model (SRM) to test the impacts of climate change on streamflow of snow-fed systems. In this study, the hydrological effects of climate change are modeled over three sequential years using SRM with both typical and recommended (parameter shift) methodology. We predict the impacts of climate change on water resources of the five most productive watersheds tributary to the Rio Grande.\  These basins collectively supply more than 75\% of the total river volume. Surface temperature and precipitation from atmosphere-ocean general circulation models (GCM) from the coupled model intercomparison project CMIP3 and CMIP5 multi-model data set are downscaled to weather stations used to force the SRM.\  Period change analysis (1990-2000) vs. (2090-2100) is used to derive temperature and precipitation changes for 55 GCM simulations. However, for each basin we subsample the range of uncertainty characterized by these 55 GCMs into only four extreme mean states representing warmer/wetter, warmer/drier, hotter/wetter, and hotter/drier mean future projections. Results indicate an increase in temperature between 3.0-6.2 {\textdegree}C and an 18\% decrease to 26\% increase in precipitation. Following parameterization of SRM, the difference between measured and computed volume is 10\% and Nash-Sutcliffe Efficiency is 0.87. Without modifications to the snow runoff coefficient (Cs), results range from a reduction in total volume of 21\% to an increase in total volume of 4\% ((hotter/drier (-21\%); warmer/drier (-18\%); hotter/wetter (3\%); warmer/wetter (4\%)). Despite an increase in precipitation in the hotter/wetter scenario, total volume decreased in three of five simulated basins.\  Modifications to Cs resulted in a 0 to 16\% difference in simulated annual volume. Results indicate future application of SRM should include a parameter shift representing the changed climate.

}, author = {Emile H. Elias and A. Rango and Caitriana Steele and Mejia, John and Ruben Baca and D. K. James and Scott T. Schrader} } @article {JRN52697, title = {Social vulnerability to climate change in primary producers: a typology approach }, journal = {Agriculture, Ecosystems and Environment}, volume = {186}, year = {2014}, month = {02/2014}, pages = {86-93}, chapter = {86}, abstract = {

Adaptation in agro-ecological systems will be important for moderating the impacts of climate change. Vulnerability assessments provide the basis for developing strategies to reduce social vulnerability and plan for climate adaptation. Primary industries have been identified as the most vulnerable industry sector globally. We review how primary producers might be socially vulnerable to climate change and develop a \‘vulnerability typology\’ of cattle producers based on survey responses from 240 producers across northern Australia. We measured social vulnerability according to ten indicators of climate sensitivity (resource dependency) and four indicators of adaptive capacity. Using a K-means clustering analysis we identified four main \‘types\’ of cattle producers. Type 1 producers (43\%) were vulnerable because they had low strategic skills and low interest in changing behaviour. Mean age was 59 years old, they were weakly networked within the industry and businesses were small. Type II producers (41\%) had low strategic skills, poorly managed risk and uncertainty, had medium sized businesses and were 51 years old on average. Only 16\% of producers (Type III and IV) appeared to have resilience to change. Type III producers (13.4\%) had a stronger psychological and financial buffer, were 52 years old on average, were well-networked and managed or owned larger businesses. Type IV producers (2.6\%) managed risk well, liked to experiment with options and were interested in change. They were 41 years old on average, managed large properties, were well-networked, perceived themselves as responsible for the future productivity of their land and were early adopters of new technology. By providing knowledge of the different ways in which people can be vulnerable to climate change, vulnerability assessments can enable decision-makers to prioritise their efforts, provide a basis for early engagement, and tailor a range of adaptation approaches to most effectively accommodate and support the divergent requirements of different \"types\" of resource users.

}, keywords = {adaptive capacity, barriers to change, climate impacts, climate sensitivity, resource dependency, Social resilience}, doi = {10.1016/j.agee.2014.01.004}, url = {/files/bibliography/14-002.pdf}, author = {Marshall, Nadine and C.J. Stokes and Nicholas Webb and Marshall, Paul and Lankester, Ally} } @inbook {JRN54033, title = {Soils as generators and sinks of inorganic carbon in geologic time}, booktitle = {Soil Carbon. Progress in Soil Science, 27}, year = {2014}, pages = {27-36}, publisher = {Springer International Publishing Switzerland}, organization = {Springer International Publishing Switzerland}, chapter = {3}, abstract = {

Soil is a continuum in geologic time. Like today, pedogenesis in the geologic past altered soils by transformations, translocations, additions, and losses as continents drifted and collided across global climatic zones. One of the major biogeochemical systems operating in soils across geologic time is the carbonic acid system, which includes gaseous CO2(g), dissolved CO2(aq), carbonic acid H2CO3(aq), bicarbonate HCO3- (aq), carbonate CO3 2- (aq), and solid-phase calcium carbonate (mainly calcite). These chemical species, collectively referred to as inorganic carbon, increased in the Silurian when vascular plants colonized the continents and began pumping atmospheric CO2 into soils via photosynthesis and root respiration, which accelerated mineral weathering and made soils {\textquotedblleft}generators{\textquotedblright} of bicarbonate. In humid regions soils are {\textquotedblleft}flushing{\textquotedblright} and bicarbonate enters groundwater, streams, and is transported to the oceans. In arid regions soils are {\textquotedblleft}non-flushing{\textquotedblright} and bicarbonate is not linked to the hydrological system, but precipitates in soil as pedogenic carbonate, making arid soils sinks of inorganic carbon. Pedogenic carbonate is documented in paleosols throughout the Cenozoic, Mesozoic, and back into the Silurian of mid-Paleozoic time. Paleogeographic maps from Present to Precambrian are useful for revealing where arid regions were located in geologic time and how they expanded and contracted; thus, propounding the question of how (and if) a currently expanding {\textquotedblleft}Aridosphere{\textquotedblright} will impact the global carbon cycle.

}, keywords = {carbon sequestration, deserts, paleosols, pedogenic carbonate}, doi = {10.1007/978-3-319-04084-4_3}, url = {files/bibliography/JRN00630.pdf}, author = {Curtis H. Monger} } @conference {JRN53988, title = {Surface water and shallow groundwater interactions in semiarid agro-ecosystems of western USA}, booktitle = {EGU General Assembly 2014}, year = {2014}, month = {04/2014}, publisher = {European Geosciences Union}, organization = {European Geosciences Union}, address = {Vienna, Austria}, abstract = {

Surface water and groundwater interactions in agro-ecosystems of semiarid regions can translate into multiple hydrological benefits including aquifer recharge, temporary storage, and delayed return flow. Our ongoing research effort aimed to better understand surface water and shallow groundwater interactions and their contribution to aquifer recharge and stream flow is being conducted in five relatively narrow floodplains in the semiarid western United States. Over the last several years, we have monitored multiple hydrologic parameters in three flood irrigated valleys of northern New Mexico. This year we are monitoring two sprinkler-irrigated floodplain valleys in semiarid landscapes of eastern Oregon. At all locations, we measure multiple hydrologic parameters including irrigation diversions, soil moisture, shallow groundwater fluctuations, and weather variables. Data collected are being used to quantify different water budget components such as deep percolation, waterway seepage, evapotranspiration, and aquifer recharge. Results from one of our study sites in New Mexico showed that on average, canal seepage was 12\%, and deep percolation ranged from 9 to 32\% out of total canal inflow during the irrigation season. Also, shallow aquifer recharge ranged from 1044 to 1350 mm yr-1 during a 3-year evaluation period. At a second study site, canal seepage was 59\% and deep percolation averaged 30\% of total water diverted. Timing and magnitude of surface water and shallow groundwater interactions is also being evaluated. Results show that replenishment of the shallow aquifer follows a seasonal pattern, driven primarily by canal seepage and irrigation percolation contributions. At one of our study sites, each year the water table reaches a peak of up to 0.8 m within three to five weeks after the onset of irrigation; this increase in water table levels is maintained throughout most of the irrigation season that ends in October. After the end of irrigation season, in the winter time, the river acts as a drain and the water table drops to baseline levels. This is similar to the other two study sites being evaluated in New Mexico. For the two study sites in Oregon, because of the use of the use of less-water application systems we expect to see a more muted response regarding water table response to irrigation percolation inputs. Results from this research effort enhance understanding of surface water and groundwater interactions and the role that irrigation plays in providing soil and aquifer recharge in agro-ecosystems of arid and semiarid environments.

}, author = {Carlos Ochoa and Guldan, Steve and Alexander Fernald and Tidwell, Vince and Emile H. Elias and Gutierrez, Karina and Borman, Mike} } @proceedings {JRN54044, title = {The southern Kalahari as a dust source: preliminary results from the field}, year = {2014}, month = {07/2014}, pages = {p. 326}, publisher = {International Society of Aeolian Research (ISAR)}, address = {Lanzhou, China}, abstract = {

The Kalahari encompasses one of the largest drylands in the Southern Hemisphere and it is a potentially large source of atmospheric dust in its relatively low-dust region.\  The severe iron depletion in the southern Indian and Atlantic Oceans, the ocean basins that receive much of the Kalahari dust, suggests that even incremental increases in dust export to these basins could have significant impact on ocean productivity. The Kalahari also provides an excellent \“natural laboratory\”, due to its consistent Kalahari Sands existing along a strong precipitation gradient (from ~850 mm in southern Zambia to ~150 mm in southwestern Botswana) with a range of different land uses and land use intensities. A large-scale field campaign to evaluate the potential of the southern Kalahari to produce atmospheric dust was established in August, 2013. The goal of the experiment is to evaluate the potential of climate change and land-use to contribute to dust production. The experiment includes measurement of horizontal flux, vegetation structure, and meteorological variables. Novel estimates were made of dust production efficiency (vertical flux produced per unit of horizontal flux) through the coordinated use of active aerosol samplers and passive horizontal sediment traps.\  In addition, a new stereophotographic method using an unmanned aerial vehicles for the estimation of wind-relevant vegetation parameters has been developed for this project. Our preliminary field data and modeling results indicate that land use and climate can have a significant impact on the potential for dust emission from the region, but new field estimates of dust emission efficiency suggest that the absolute magnitude of dust emitted from the region might, at present, be lower than previously thought.

}, author = {Gregory S. Okin and Nicholas Webb and Abinash Bhattachan and Dintwe, Kebonye and Paolo D{\textquoteright}Odorico} } @conference {JRN54412, title = {Satellite observations of ground water changes in New Mexico}, booktitle = {59th Annual New Mexico Water Conference}, year = {2014}, month = {11/2014}, address = {Santa Fe, NM}, abstract = {

In 2002 NASA launched the Gravity Recovery and Climate Experiment (GRACE)\ satellite mission. GRACE consists of two satellites with a separation of about 200 km. \ By accurately measuring the separation between the twin satellites, the differences in the gravity field can be determined.\ Monthly observations of these differences can be related to changes in the mass below the satellites. \ On land these mass changes are primarily due to movement of water and GRACE effectively weighs the total amount of water (snow, surface water, groundwater and soil moisture) entering or leaving a region each month. \ A paper published in Science in 2013 by Famiglietti and Rodell presents results for the rate of change for the observed mass over the US between 2002 and 2013. \ In particular they found the loss of water from the southern high plains aquifer to be substantial (-2.5 cm/year) and attribute this loss to an overreliance on groundwater to supply irrigation needs. \ We analyzed GRACE data for 2007 to 2013 covering a location in south central New Mexico (107.8 W and 33 N) and found a decrease in the total water stored of about 2.0 million acre feet a year over an area of 200,000 km^2.\  We believe this result reflects groundwater depletion in south central New Mexico and the lower than average regional precipitation between 2007 and 2013.

}, author = {T. J. Schmugge and Emile H. Elias and Rodell, Matt and A. Rango} } @article {JRN54396, title = {Soil animal responses to moisture availability are largely scale, not ecosystem dependent: Insight from a cross-site study}, journal = {Global Change Biology}, volume = {20}, year = {2014}, month = {02/2014}, pages = {2631-2643}, chapter = {2631}, abstract = {

Climate change will result in reduced soil water availability in much of the world either due to changes in precipitation or increased temperature and evapotranspiration. Responses of communities of mites and nematodes to changes in moisture availability are not well known, yet these organisms play important roles in decomposition and nutrient cycling processes. We determined how communities of these organisms respond to changes in moisture availability and whether common patterns occur along fine-scale gradients of soil moisture within four individual ecosystem types (mesic, xeric and arid grasslands and a polar desert) located in the western United States and Antarctica, as well as across a cross-ecosystem moisture gradient (CEMG) of all four ecosystems considered together. An elevation transect of three sampling plots was monitored within each ecosystem and soil samples were collected from these plots and from existing experimental precipitation manipulations within each ecosystem once in fall of 2009 and three times each in 2010 and 2011. We found that while both mites and nematodes increased with available soil moisture across the CEMG, within individual ecosystems increases in soil moisture resulted in decreases to nematode communities at all but the arid grassland ecosystem; mites showed no responses at any ecosystem. Changes in proportional abundances of mite and nematode trophic groups as soil moisture increased within individual ecosystems may result in shifts within soil food webs with important consequences for ecosystem functioning. We suggest that communities of soil animals at local scales may respond predictably to changes in moisture availability regardless of ecosystem type but that additional factors, such as climate variability, vegetation composition and soil properties may influence this relationship over larger scales.

}, keywords = {climate change, desert, drought, grassland, mites, nematodes}, doi = {10.1111/gcb.12522}, url = {/files/bibliography/14-037.pdf}, author = {Sylvain, Zachary A. and D.H. Wall and Karie Cherwin and Lara Reichmann and Debra C. Peters and O. E. Sala} } @article {JRN53931, title = {Sound management may sequester methane in grazed rangeland ecosystems}, journal = {Scientific Reports}, volume = {4}, year = {2014}, month = {03/2014}, chapter = {4444}, abstract = {

Considering their contribution to global warming, the sources and sinks of methane (CH4) should be accounted when undertaking a greenhouse gas inventory for grazed rangeland ecosystems. The aim of this study was to evaluate the mitigation potential of current ecological management programs implemented in the main rangeland regions of China. The influences of rangeland improvement, utilization and livestock production on CH4 flux/emission were assessed to estimate CH4 reduction potential. Results indicate that the grazed rangeland ecosystem is currently a net source of atmospheric CH4. However, there is potential to convert the ecosystem to a net sink by improving management practices. Previous assessments of capacity for CH4 uptake in grazed rangeland ecosystems have not considered improved livestock management practices and thus underestimated potential for CH4 uptake. Optimal fertilization, rest and light grazing, and intensification of livestock management contribute mitigation potential significantly.

}, doi = {10.1038/srep04444}, url = {/files/bibliography/14-005.pdf}, author = {Wang, Chengjie and G. Han and Wang, Shiping and Zhai, Xiajie and Joel R. Brown and Kris Havstad and Ma, Xiuzhi and Andreas Wilkes and Mengli Zhao and Tang, Shiming and Zhou, Pei and Jiang, Yuanyuan and Lu, Tingting and Zhongwu Wang and Li, Zhiguo} } @proceedings {JRN54045, title = {Soil organic carbon dust emission: a synthesis of recent Australian research }, year = {2014}, month = {07/2014}, pages = {p. 196}, publisher = {International Society of Aeolian Research (ISAR)}, address = {Lanzhou, China}, abstract = {

Soil erosion is an important component of the global carbon cycle. Recent research has revealed the importance of aeolian processes for soil organic carbon (SOC) flux and its impacts on carbon dynamics and ecosystem function. Here we review progress in research on the mechanisms and magnitude of SOC dust emissions in Australia. We describe how field measurements of entrainment and enrichment of SOC in dust led to a new physically-based parameterisation of SOC dust enrichment for the Computational Environmental Management System (CEMSYS) national wind erosion model. Our modelling results suggest that from 2000-2011 the total dust emission for Australia was 118 Mt yr-1 with SOC dust emissions (\<22 \µm) ~1.59 Mt yr-1. Rangelands produced ~84\% of Australia\’s SOC dust emissions (1.34 Mt yr-1). Agricultural lands produced ~0.11 Mt yr-1, but emissions were larger per unit area than rangelands. The rapid and often long-distance aeolian transport of SOC may result in the depletion of SOC at source, enrichment of downwind soils, or incorporation into aquatic and marine systems. SOC loss was likely greater in the past (since 1870s) during post-colonial agricultural expansion and reduced since the 1980s with conservation agriculture. This impacted soil function and productivity of rangelands and cropping lands. The impact on land surface\–atmosphere interactions is likely also considerable, but large uncertainty remains over mineralisation rates of SOC and its fate in the atmosphere. Our results demonstrate the need for aeolian processes to be given greater significance in terrestrial carbon cycling, and for the inclusion of dust emission schemes in Earth systems models and carbon accounting systems.

}, author = {Nicholas Webb and A. Chappell and Craig Strong and Harry Butler and Samuel K. Marx and John Leys and Grant McTainish and Viscarra-Rossell, Raphael} } @article {JRN54179, title = {Spatial distribution and risk assessment of Johnsongrass (sorghum halepense) in Big Bend National Park, Texas}, year = {2014}, pages = {161-168}, publisher = {US Department of Interior; US Geological Survey}, chapter = {Scientific Invesigations Report 2012-5162}, abstract = {

We used Landsat 7 ETM+ imagery to illustrate how remotely sensed data can model predicted Johnsongrass habitat. We used spectral reflectance values for three seasons of data across 5 years (fall 1999, summer and fall 2000, spring and fall 2001, spring 2002, and spring 2003) to capture Johnsongrass vegetation phenology. Johnsongrass occurrences in BIBE consisted of 147 georeferenced localities.\ \  We used the program Maxent to predict Johnsongrass distributions. Maxent is a general approach for modeling species distributions using presence-only data sets. Maxent estimates a target probability distribution by finding the probability distribution of maximum entropy (the distribution that is most spread out, or closest to uniform). Maxent uses pixels with known species occurrence records to constitute the sample points. Remotely sensed and GIS data sets can provide environmental variables measured at each sample point. Analysis output includes a probabilistic interpretation, grading from least to most suitable habitat conditions.\  We evaluated the Johnsongrass predicted habitat model in Maxent by withholding 10 percent of the occurrence locations for testing. This approach, considered threshold-dependent, used a binomial test based on omission and predicted area. Model performance is evaluated using extrinsic omission rate and the proportion of all the pixels that are predicted as suitable habitat. The second approach to evaluating model performance is considered a threshold-independent procedure and uses receiver operating characteristic (ROC) curves. The advantage of ROC analysis is that area under the ROC curve (AUC) provides a single measure of model performance, independent of any particular choice of threshold. The AUC can be interpreted as the likelihood that habitat quality is correctly classified by the predictive model at randomly selected sites.

}, doi = {10.3133/sir20125162}, url = {/files/bibliography/14-043.pdf}, author = {Kendal Young and Scott T. Schrader} } @article {49835, title = {Sheep Laterality}, journal = {Laterality}, volume = {18}, year = {2013}, month = {03/2013}, pages = {179-193}, chapter = {179}, abstract = {\  Turning preferences among 309 white-faced ewes were individually evaluated in an enclosed, artificially lit T-maze, followed by each ewe choosing either a right or left return alley to return to peers. Data recorded included time in the start box, time in the T-maze, exit arm chosen to leave the T-maze, and return alley. Right and left arms of the T-maze were chosen 65.7\% and 34.3\% of the time, respectively, while right and left return alleys were chosen 32.4\% and 67.6\%, respectively. Exit arm and return alley were not independently chosen (pB.0001), with observed counts being higher than expected under independence when ewes made the same choice for exit and alley (RR or LL turn patterns) and being lower than expected for alternating choices (RL or LR). Out of the 309 ewes, 28.2\% and 30.1\% chose RR and LL turn patterns, respectively, while 37.5\% chose the RL turn pattern, but only 13 (4.2\%) chose the LR turning pattern. Overall, ewes that initially turned right when presented a second turning opportunity had a slight preference to alternate their turning direction, while ewes that initially turned left tended to continue turning left when given another chance to turn. Exit arm and return alley laterality was not related (a_.05) to time of day the test was administered, ewe\’s age or genetics, most recent liveweight, or most recent shorn fleece weight. The mean time spent in the start box (21 s) was not related to exit arm (p_.947) or return alley (p_.779).\  Mean time (15 s) spent in the T-maze was not related to exit arm (p_.086) or return alley (p_.952). More research will be required to understand sheep turning laterality and how it can impact working facilities and research equipment.}, keywords = {behavioural lateralisation, handedness, livestock behaviour, T-maze}, doi = {10.1080/1357650X.2011.647919}, url = {/files/bibliography/12-008.pdf}, author = {D.M. Anderson and L. W. Murray} } @article {49834, title = {Spatiotemporal cattle data {\textendash} a plea for protocol standardization}, journal = {Positioning}, volume = {4}, year = {2013}, month = {02/2013}, pages = {114-136}, chapter = {114}, abstract = {

It was not until the end of the 1990\’s that animal born satellite receiver\’s catapulted range cattle ecology into the 21st century world of microchip technology with all of its opportunities and challenges.\  With the global navigation satellite system (GNSS) insight into how cattle use a landscape is being revealed from previously secrete temporal and spatial behaviors.\  The most common system to date deployed for studying ungulates is known as the global positioning system (GPS).\  With its use has come a clarity and completeness in documenting spatial and temporal data in new and exciting ways that offer almost unlimited possibilities to better understand and manage both the economic as well as societal returns from animal dominated landscapes required to provide multiple goods and services.\  However, its use on free-ranging cattle is not without challenges, some of which are yet to be optimally solved.\  To maximize the usefulness of GNSS data consideration must be given to: developing a standardized protocol for reporting and analyzing research that facilitates the interpretation of results across different ecosystems, develop optimum ranges over which to collect satellite fixes depending upon the particular behaviors of interest, and concurrently develop electronic hardware and equipment platforms that are easily deployed on animals that are light, robust\  and capable of being worn by cattle for extended periods of time without the need for human intervention especially to change batteries.\  Once the data are collected appropriate geographic information system (GIS) based models should be used to produce a series of visually observable flexible management strategies, some of which may support methodologies that are yet to be commercialized and adopted into future plant-animal interface management routines.

}, keywords = {animal tracking, Cattle behavior, GPS}, doi = {10.4236/pos.2013.41012}, url = {/files/bibliography/13-008.pdf}, author = {D.M. Anderson and Richard E. Estell and Andr{\'e}s F. Cibils} } @proceedings {49837, title = {State-and-transition models as guides for adaptive management: What are the needs?}, year = {2013}, month = {04/2013}, pages = {27-33}, address = {Santa Rosa, La Pampa, Argentina}, abstract = {

State and transaction models (STMs) were conceived as a means to organize information about land potential and vegetation dynamics in rangelands to be used in their management. The basic idea is to describe the plant community states that can occur on a site and the causes of transitions between these states. STMs are not bound to any particular theory about how vegetation should change, so they are flexible and able to represent succession, event-driven change, and critical or abrupt transitions to alternative sites.\  The diagrammatic and narrative portions of STMs synthesize various sources of knowledge about an ecosystem, including scientific results, historical anecdotes, and local knowledge to resent a set of explanations and predictions for how ecosystems can respond to natural events and management actions.

}, url = {/files/bibliography/13-015.pdf}, author = {Brandon T Bestelmeyer and Joel R. Brown and Bulgamaa Densambuu and Kris Havstad and Jeffrey E. Herrick and H. Raul Peinetti} } @article {49839, title = {The Savory Method can not green deserts or reverse climate change}, journal = {Rangelands}, volume = {35}, year = {2013}, pages = {72-74}, abstract = {

This is a refutation of Allan Savory claims that his "planned grazing" method was necessary to reverse desertification and climate change as presented in the video "How to green the world{\textquoteright}s deserts and reverse climate change" that was presented in session 7 at the 2013 TED (Technology, Entertainment, Design) Conference on 27 February 2013 in Long Beach, California.

Allan Savory stated that his {\textquotedblleft}planned grazing{\textquotedblright} method was necessary to reverse two of the world{\textquoteright}s most challenging and interlinked global change processes{\textemdash}desertification and climate change{\textemdash}in the video {\textquotedblleft}How to green the world{\textquoteright}s deserts and reverse climate change{\textquotedblright} that was presented in session 7 at the 2013 TED (Technology, Entertainment, Design) Conference on 27 February 2013 in Long Beach, California.i As members of the scientific community, it is our obligation to evaluate the claims made in this video relative to the existing scientific information on this topic.

We find all of Mr Savory{\textquoteright}s major claims to be unfounded and we express deep concern that they have the potential to undermine proven, practical approaches to rangeland management and restoration that are supported by a global community of practitioners and scientists. The two major assumptions underlying Mr Savory{\textquoteright}s presentation are alone sufficient grounds for extreme skepticism. First is that humans have misunderstood the basic grassland{\textendash}grazer relationships for centuries and that only he knows the true nature of this relationship. Second is that use of intensive, concentrated livestock grazing, specific to the method that Mr Savory developed, is the only viable solution to reverse desertification and climate change. In addition to challenging these two highly problematic assumptions, we present a spe-cific critique of three invalid arguments that Mr Savory used to claim that his grazing method can reverse desertification, climate change, and alleviate human suffering and death (19:00 in video).

}, keywords = {climate change, desertification, planned grazing}, doi = {10.2111/RANGELANDS-D-13-00044.1}, url = {/files/bibliography/13-034.pdf}, author = {D.D. Briske and Brandon T Bestelmeyer and Joel R. Brown and S. Fuhlendorf and Polley, H. Wayne} } @article {49842, title = {Soil organic carbon dust emission: an omitted global source of atmospheric CO2}, journal = {Global Change Biology}, volume = {19}, year = {2013}, month = {07/2013}, pages = {3238-3244}, chapter = {3238}, abstract = {

Soil erosion redistributes soil organic carbon (SOC) within terrestrial ecosystems, to the atmosphere and oceans. Dust export is an essential component of the carbon (C) and carbon dioxide (CO2) budget because wind erosion contributes to the C cycle by removing selectively SOC from vast areas and transporting C dust quickly offshore; augmenting the net loss of C from terrestrial systems. However, the contribution of wind erosion to rates of C release and sequestration is poorly understood. Here we describe how SOC dust emission is omitted from national C accounting, is a neglected source of CO2 and a likely accelerant of SOC decomposition. Similarly, long dust residence times in the unshielded atmospheric environment may considerably increase CO2 emission. We developed a first approximation to SOC enrichment for a well-established dust emission model and quantified SOC dust emission for Australia (5.83 Tg CO2-e y-1) and Australian agricultural soils (0.4 Tg CO2-e y-1). These amount to under-estimates for CO2 emissions of ~10\% from combined C pools in Australia (yr=2000), ~5\% from Australian Rangelands and ~3\% of Australian Agricultural Soils by Kyoto Accounting. Northern hemisphere countries with greater dust emission than Australia are also likely to have much larger SOC dust emission. Therefore, omission of SOC dust emission likely represents a considerable underestimate from those nations{\textquoteright} C accounts. We suggest that the omission of SOC dust emission from C cycling and C accounting is a significant source of uncertainty. Tracing the fate of wind-eroded SOC in the dust cycle is therefore essential to quantifying the release of CO2 from SOC dust to the atmosphere and the contribution of SOC deposition to downwind C sinks.

}, keywords = {Australia, carbon accounting, carbon budgets, carbon dioxide, dust emission, soil organic carbon}, doi = {10.1111/gcb.12305}, url = {/files/bibliography/13-023.pdf}, author = {A. Chappell and Nicholas Webb and Harry Butler and Craig Strong and Grant McTainish and John Leys and Raphael A. Viscarr Rossel} } @proceedings {49843, title = {Sustainable livestock production on rangelands: Emerging trends in the USA}, year = {2013}, month = {04/2013}, pages = {37-43}, address = {Santa Rosa, La Pampa, Argentina}, abstract = {

A recent review of statistics published by the United Nations Food and Agriculture Organization showed that global livestock numbers have increased steadily over the past 30 years.\  By 2030, livestock numbers in the developing world are expected to reach record highs that will surpass livestock population levels of the entire planet recorded at the turn of the 20th century while by native grassland areas worldwide are expected to shrink by more than 12 million hectares over the same time period.\  This predicted trend is likely to trigger a substantial increase in forage demand, placing unprecedented pressures on rangelands of developing nations.\  The review of FAO data also revealed that counter to global trends, livestock inventories of developed countries have tended to decrease over the same period.\  This phenomenon has been particularly evident on rangelands of the western US where management emphasis has shifted from heavy investments in land improvements (common until the 1970s) to systems characterized by low capital investment focused on optimizing efficiency of per-capita livestock production.\  Knowledge-intensive management approaches involving selection of livestock biotypes better adapted to arid environments, and development of geospatial technology that allow more precise manipulation of the ruminant/plant interface have emerged as a result of this trend.\  Nonetheless, expected increases in the price of oil and costs of agricultural crop production used as animal feed could dramatically change this scenario, augmenting the role fo rangelands as a source of forage for US livestock in the near future.\  Thus, development of strategies to increase sustainable herbivory of a broader array of native arid land forages (including woody plants) will most probably become a top priority shred by pastoral livestock systems of the developed and developing work alike.

}, url = {/files/bibliography/13-016.pdf}, author = {Andr{\'e}s F. Cibils and Richard E. Estell and Jerry L. Holechek and D.M. Anderson} } @proceedings {JRN52657, title = {Sustainable rangeland-based livestock production: A perspective on USA and global emerging trends}, year = {2013}, month = {10/2013}, pages = {79-85}, address = {Mexicali, Baja California}, abstract = {

A recent review of statistics published by the United Nations Food and Agriculture Organization showed that global livestock numbers have increased steadily over the past 30 years. By 2030, livestock numbers in the developing world are expected to reach record highs that will surpass livestock population levels of the entire planet recorded at the turn of the 20th century while native grassland areas worldwide are expected to shrink by more than 12 million hectares over the same time period. This predicted trend is likely to trigger a substantial increase in forage demand, placing unprecedented pressures on rangelands of developing nations. The review of FAO data also revealed that counter to global trends, livestock inventories of developed countries have tended to decrease over the same period. This phenomenon has been particularly evident on rangelands of the western US where management emphasis has shifted from heavy investments in land improvements (common until the 1970s) to systems characterized by low capital investment focused on optimizing efficiency of per-capita livestock production. Knowledge-intensive management approaches involving selection of livestock biotypes better adapted to arid environments, and development of geospatial technology that allow more precise manipulation of the ruminant/plant interface have emerged as a result of this trend. Nonetheless, expected increases in the price of oil and costs of agricultural crop production used as animal feed could dramatically change this scenario, augmenting the role of rangelands as a source of forage for US livestock in the near future. Thus, development of strategies to increase sustainable herbivory of a broader array of native arid land forages (including woody plants) will most probably become a top priority shared by pastoral livestock systems of the developed and developing world alike.

}, url = {/files/bibliography/13-028.pdf}, author = {Andr{\'e}s F. Cibils and Richard E. Estell and Jerry L. Holechek and D.M. Anderson} } @article {49844, title = {Sensitivity of grassland plant community composition to spatial vs. temporal variation in precipitation}, journal = {Ecology}, volume = {94}, year = {2013}, month = {08/2013}, pages = {1687-1696}, abstract = {

Climate gradients shape spatial variation in the richness and composition of plant communities. Given future predicted changes in climate means and variability, and likely regional variation in the magnitudes of these changes, it is important to determine how temporal variation in climate influences temporal variation in plant community structure. Here, we evaluated how species richness, turnover, and composition of grassland plant communities responded to interannual variation in precipitation by synthesizing long-term data from grasslands across the United States. We found that mean annual precipitation (MAP) was a positive predictor of species richness across sites, but a positive temporal relationship between annual precipitation and richness was only evident within two sites with low MAP. We also found higher average rates of species turnover in dry sites that in turn had a high proportion of annual species, although interannual rates of species turnover were surprisingly high across all locations. Annual species were less abundant than perennial species at nearly all sites, and our analysis showed that the probability of a species being lost or gained from one year to the next increased with decreasing species abundance. Bray-Curtis dissimilarity from one year to the next, a measure of species composition change that is influenced mainly by abundant species, was insensitive to precipitation at all sites. These results suggest that the richness and turnover patterns we observed were driven primarily by rare species, which comprise the majority of the local species pools at these grassland sites. These findings are consistent with the idea that shortlived and less abundant species are more sensitive to interannual climate variability than longerlived and more abundant species. We conclude that, among grassland ecosystems, xeric grasslands are likely to exhibit the greatest responsiveness of community composition (richness and turnover) to predicted future increases in interannual precipitation variability. Over the long term, species composition may shift to reflect spatial patterns of mean precipitation; however, perennial-dominated systems will be buffered against rising interannual variation, while systems that have a large number of rare, annual species will show the greatest temporal variability in species composition in response to rising interannual variability in precipitation.

}, keywords = {annual species, climate variability, community composition, mean annual precipitation, species richness, species turnover}, doi = {10.1890/12-1006.1}, url = {/files/bibliography/13-031.pdf}, author = {Cleland, Elsa E. and S.L. Collins and Dickson, Timothy L. and Farrer, Emily C. and K.L. Gross and Laureano A. Gherardi and Hallett, Lauren M. and Richard J. Hobbs and Hsu, Joanna S. and Turnbull, Laura and Katharine N. Suding} } @article {49853, title = {Soil-litter mixing accelerates decomposition in a Chihuahuan Desert grassland}, journal = {Ecosystems}, volume = {16}, year = {2013}, month = {03/2013}, pages = {183-195}, chapter = {183}, abstract = {Decomposition models typically under-predict decomposition relative to observed rates in drylands. This discrepancy indicates a significant gap in our mechanistic understanding of carbon and nutrient cycling in these systems. Recent research suggests that certain drivers of decomposition that are often not explicitly incorporated into models (for example, photodegradation and soil\–litter mixing; SLM) may be important in drylands, and their exclusion may, in part, be responsible for model under-predictions. To assess the role of SLM, litterbags were deployed in the Chihuahuan Desert and interrelationships between vegetation structure, SLM, and rates of decomposition were quantified. Vegetation structure was manipulated to simulate losses of grass cover from livestock grazing and shrub encroachment. We hypothesized that reductions in grass cover would promote SLM and accelerate mass loss by improving conditions for microbial decomposition. Litter mass decreased exponentially, with the greatest losses occurring in concert with summer monsoons. There were no differences in decay constants among grass cover treatments. A significant, positive relationship between mass loss and SLM was observed, but contrary to expectations SLM was independent of grass cover. This suggests that processes operating at finer spatial scales than those in our grass removal treatments were influencing SLM. Shifts in litter lipid composition suggest increased bacterial contribution to decomposition through time. SLM, which is seldom included as a variable controlling decomposition in statistical or mechanistic models, was a strong driver of decomposition. Results are discussed in the context of other known drivers of decomposition in drylands (for example, UV radiation and climate) and more mesic systems.}, keywords = {arid, carbon cycle, decomposition, dryland, dust, erosion, livstock grazing, phospholipid fatty acids, Prosopis, shrub encroachment, soil-litter mixing}, doi = {10.1007/s10021-012-9604-5}, url = {/files/bibliography/13-019.pdf}, author = {Hewins, Daniel B. and Steven R. Archer and Gregory S. Okin and McCulley, Rebecca L. and Heather L. Throop} } @article {JRN52687, title = {Soil organic carbon enrichment of dust emissions: Magnitude, mechanisms and its implications for the carbon cycle}, year = {2013}, abstract = {

Soil erosion is an important component of the global carbon cycle. However, little attention has been given to the role of aeolian processes in influencing soil organic carbon (SOC) flux and the release of greenhouse gasses, such as carbon-dioxide (CO2), to the atmosphere.\  Understanding the magnitude and mechanisms of SOC enrichment in dust emissions is necessary to evaluate the impact of wind erosion on the carbon cycle. This research examines the SOC content and enrichment of dust emissions measured using Big Spring Number Eight (BSNE) wind-vane samplers across five land types in the rangelands of western Queensland, Australia. Our results show that sandy soils and finer particulate quartz-rich soils are more efficient at SOC emission and have larger SOC dust enrichment than clay-rich aggregated soils. The SOC enrichment ratios of dusts originating from sites with sand-rich soil ranged from 2.1-41.9, while the mean enrichment ratio for dusts originating from the clay soil was 2.1. We hypothesise that stronger inter-particle bonds and the low grain density of the aggregated clay soil explain its reduced capacity to release SOC during saltation, relative to the particulate sandy soils. We also show that size-selective sorting of SOC during transport may lead to further enrichment of SOC dust emissions. Two dust samples from regional transport events were found to contain 15-20\% SOC. These preliminary results provide impetus for additional research into dust SOC enrichment processes to elucidate the impact of wind erosion on SOC flux and reduce uncertainty about the role of soil erosion in the global carbon cycle.

}, keywords = {aeolian dust, carbon cycle, rangelands, soil nutrients, wind erosion}, doi = {10.1002/esp.3404}, url = {/files/bibliography/13-032.pdf}, author = {Nicholas Webb and Craig Strong and A. Chappell and Samuel K. Marx and Grant McTainish} } @article {49872, title = {Soil coverage reduces photodegradation and promotes the dvelopment of soil-microbial films on dryland leaf litter}, journal = {Ecosystems}, volume = {15}, year = {2012}, pages = {311-321}, chapter = {311}, abstract = {

Litter decomposition is a central focus of ecosystem science because of its importance to biogeochemical pools and cycling, but predicting dryland decomposition dynamics is problematic. Some studies indicate photodegradation by ultraviolet (UV) radiation can be a significant driver of dryland decomposition, whereas others suggest soil{\textendash}litter mixing controls decomposition. To test the influence of soil coverage on UV photodegradation of litter, we conducted a controlled environment experiment with shrub (Prosopis velutina) leaf litter experiencing two UV levels and three levels of coverage with dry sterile soil. Under these conditions, decomposition over 224 days was enhanced by UV, but increasing soil coverage strongly and linearly diminished these effects. In a complementary study, we placed P. glandulosa leaf litter in different habitats in the field and quantified litter surface coverage by soil films. After 180 days, nearly half of the surface area of litter placed under shrub canopies was covered by a tightly adhering film composed of soil particles and fungal hyphae; coverage was less in grassy zones between shrubs. We propose a conceptual model for the shifting importance of photodegradation and microbial decomposition over time, and conclude that (1) soil deposition can ameliorate the direct effects of UV photodegradation in drylands and (2) predictions of C losses based solely on UV effects will overestimate the importance of this process in the C cycle. An improved understanding of how development of the soil{\textendash}litter matrix mediates the shift from abiotic (photodegradation) to biotic (microbial) drivers is necessary to predict how ongoing changes in land cover and climate will influence biogeochemistry in globally extensive drylands.

}, keywords = {carbon cycle, decomposition, dryland, Jornada, litter, mesquite, photodegradation, Prosopis, soil erosion, soil-litter mixing, soil-microbial films, ultraviolet radiation}, doi = {10.1007/s10021-011-9511-1}, url = {/files/bibliography/12-019.pdf}, author = {Barnes, Paul W. and Heather L. Throop and Hewins, Daniel B. and Abbene, Michele L. and Steven R. Archer} } @article {49878, title = {A synthetic review of feedbacks and drivers of shrub encroachment in arid grasslands}, journal = {Ecohydrology}, volume = {5}, year = {2012}, month = {10/2012}, pages = {520-530}, chapter = {520}, abstract = {Many arid grasslands around the world are affected by woody plant encroachment and the replacement of a relatively continuous grass cover with shrub patches bordered by bare soil. This shift in plant community composition is often abrupt in space and time, suggesting that it is likely sustained by positive feedbacks between vegetation and environmental conditions (e.g., resource availability) or disturbance regime (e.g., fire or freeze). These feedbacks amplify the effects of drivers of shrub encroachment, i.e., of conditions favoring a shift from grass to shrub dominance (e.g., overgrazing, climate change). Here we review some major drivers and feedbacks and identify the basic stages in the transition from grassland to shrubland. We discuss some possible scenarios of interactions between drivers and feedbacks that could explain the transition from a stage to the next, and the potential irreversibility of the shift from grass to shrub dominance. We introduce a simplistic modeling framework that can integrate the various drivers to explain the emergence of bistability for shrub-encroached grassland systems.}, keywords = {climate change, fire ecology, shrub encroachment, soil erosion, sptial dynamics}, doi = {10.1002/eco.259}, url = {/files/bibliography/12-024.pdf}, author = {Paolo D{\textquoteright}Odorico and Gregory S. Okin and Brandon T Bestelmeyer} } @inbook {49884, title = {Sustainable soils: Synthesis}, booktitle = {Soil Ecology and Ecosystem Sevices}, year = {2012}, pages = {395-396}, publisher = {Oxford University Press}, organization = {Oxford University Press}, abstract = {

The six chapters of the "Sustainable Soils" section of the book "Soil Ecology and Ecoystem Services" support the fundamental role that soil biota play in sustaining soil structure and nutrient cycling as the foundation for nearly all ecosystem services while illustrating the challenges of documenting explicit, consistent relationships. Provisioning services, including crop production, were the focus of the majority of the studies cited in this section and a high proportion of the management system comparisons are limited to conventional tillage against some form of organic or conservation tillage-based system. Despite these inherent limitations of the existing literature, a number of lessons can be drawn. Five that are particularly significant were each cited in at least two of the chapters: (1) the importance of spatial and temporal context for interpreting soil biota-sustainability relationships, (2) the importance of systematic approaches, common methods, and protocols to study soil biota {\textendash} sustainability relationships, (3) the value of long-term studies for identifying and validating functional relationships, particularly where chronic, cumulative and acute disturbances are involved, (4) the potential value of local knowledge for identifying, documenting and monitoring these relationships, and (5) the extent to which hysteresis must be considered to understand and predict the potential contribution of soil biota to resilience and restoration.

}, keywords = {book chapter}, url = {files/bibliography/12-Synthesis-Herrick.pdf}, author = {Jeffrey E. Herrick and J. Six} } @article {49887, title = {A strategy for rangeland management based on best available knowledge and information}, journal = {Rangeland Ecology and Management}, volume = {65}, year = {2012}, month = {11/2012}, pages = {638-646}, chapter = {638}, abstract = {

Changes to rangeland systems are happening at spatial and temporal scales beyond the capability of our current knowledge and information systems. In this paper we look at how Web 2.0 tools such as wikis and crowd-sourcing and new technologies including mobile devices and massive online databases are currently being used in rangeland management and consider the potential of these tools for furthering understanding of rangeland ecosystems and improving management decision making in the future. Some potential problems and barriers associated with implementing Web 2.0 tools to support a new rangeland knowledge and information management paradigm are discussed.\  We conclude with a proposed roadmap for moving the discipline of rangeland ecology and management forward toward a more robust and effective use of information. This roadmap focuses on interoperability of data and systems, improving data consistency and documentation, geographic referencing of information, the use of structured and unstructured information, and targeted learning and teaching. Our proposal is an incremental step on top of our current ways of collecting, using, and disseminating information that moves us toward the kinds of knowledge systems we need to address the management problems of today and tomorrow.

}, keywords = {ecological site, hierarchy theory, information system, integrated knowledge system, scale}, doi = {10.2111/REM-D-12-00021.1}, url = {/files/bibliography/12-033.pdf}, author = {Jason W. Karl and Jeffrey E. Herrick and Dawn M. Browning} } @inbook {49904, title = {Sustainable soils: Introduction}, booktitle = {Soil Ecology and Ecosystem Services}, year = {2012}, pages = {299-300}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {UK}, abstract = {

The six chapters in the final section of the book address the role of soil biota in a wider context of maintaining soil resources for sustaining the earth{\textquoteright}s capacity to provide critical ecosystem services. This is quite possibly the most important, and frequently overlooked, function that soil biota provide. Without soil biota, the soil resource as we know it would not exist, and soil recovery in most ecosystems would proceed at orders of magnitude less than a snail{\textquoteright}s pace. Net primary productivity would be dramatically reduced by much slower rates of nutrient cycling, and therefore lower plant nutrient availability and nutrient effects would be exacerbated by water limitations as the lack of a stable soil structure would maintain relatively low plant available water holding capacities and even lower infiltration rates. Together, these chapters provide a summary of current knowledge and remaining challenges to identify, measure and generalize the importance of soil biota for sustaining soil resources and their related ecosystem services in agroecosystems.

}, isbn = {13: 978-0199575923}, url = {files/bibliography/12-Intro-Fix_Herrick.pdf}, author = {J. Six and Jeffrey E. Herrick} } @article {49907, title = {Spatially explicit representation of state-and-transition models}, journal = {Rangeland Ecology and Management}, volume = {65}, year = {2012}, month = {05/2012}, pages = {213-222}, chapter = {213}, abstract = {The broad-scale assessment of natural resource conditions (e.g., rangeland health, restoration needs) requires knowledge of their spatial distribution. We argue that creating a database that links state-and-transition models (STMs) to spatial units is a valuable management tool for structuring ground-based observations, management planning for landscapes, and for housing information on the responses of land areas to management actions. To address this need, we introduce a multi-factor classification system based on ecological sites and STMs that is directly linked to recent concepts of vegetation dynamics in rangelands. We describe how this classification was used as a basis for creating a spatial database and maps of ecological states. We provide an example of how the classification and mapping has been applied in over 1.2 million ha of public rangelands in southern New Mexico using aerial photo interpretation supplemented with existing inventory data and rapid field assessments. The resulting state map has been used by the Bureau of Land Management (BLM) to design landscape-level shrub control efforts, structure and report district-wide rangeland health assessments, and to evaluate locations for energy development. We conclude by discussing options for the development of state maps and their current limitations, including the use of satellite imagery and concepts for defining states. We argue that cataloging ecological states in a spatial context has clear benefits for rangeland managers because it connects STM concepts to specific land areas. State mapping also provides a means to generate and store spatially-explicit data resulting from tests of the propositions in STMs and conservation practices.}, keywords = {alternative states, ecological sites, geographic information systems, land classification, Soil Survey Geographic (SSURGO) Database}, doi = {10.2111/REM-D-11-00047.1}, url = {/files/bibliography/12-022.pdf}, author = {Caitriana Steele and Brandon T Bestelmeyer and Laura M. Burkett and Phil Smith and Yanoff, Steve} } @article {49910, title = {Spatial patterns, processes and predictions in ecohydrology: integrating technologies to meet the challenge}, journal = {Ecohydrology}, volume = {5}, year = {2012}, pages = {235-241}, abstract = {

Spatial organization is the pre-eminent challenge of ecohydrology as a geospatial science. Ecohydrological patterns emerge as a result of interactions of fine-scale processes and functions that are difficult to observe, quantify and predict. As a result, an integrated approach to the study of spatial patterns in ecohydrology requires a more focused engagement of sampling, sensing and computational tools that are presently available to the scientific community. Here, an incremental and iterative process is proposed consisting of field experiments sequenced with distributed ecohydrological modelling aimed at identifying emergent spatial patterns. In this commentary, three case studies are presented that illustrate how the integration of spatial technologies can provide new insights into the ecohydrological patterns of arid and semiarid ecosystems. The search for emergent ecohydrological behaviour arising from cross-scale interactions can also yield improved process understanding, predictive capabilities and relevance to societal needs. Copyright {\textcopyright} 2012 John Wiley \& Sons, Ltd.

}, keywords = {cross-scale interactions, North American monsoon, numerical modelling, remote sensig, sensor networks, spatial organization}, doi = {10.1002/eco.1248}, url = {files/bibliography/JRN00604.pdf}, author = {Enrique Vivoni} } @book {JRN54511, title = {Soil Ecology and Ecosystem Services}, year = {2012}, pages = {424}, publisher = {Oxford University Press}, organization = {Oxford University Press}, abstract = {

This multi-contributor, international volume synthesizes contributions from the world{\textquoteright}s leading soil scientists and ecologists, describing cutting-edge research that provides a basis for the maintenance of soil health and sustainability. The book covers these advances from a unique perspective of examining the ecosystem services produced by soil biota across different scales - from biotic interactions at microscales to communities functioning at regional and global scales. The book leads the user towards an understanding of how the sustainability of soils, biodiversity, and ecosystem services can be maintained and how humans, other animals, and ecosystems are dependent on living soils and ecosystem services.

}, isbn = {10: 0199575924}, author = {D.H. Wall and Richard Bardgett and Behan-Pelletier, V. M. and Jeffrey E. Herrick and Jones, Hefin and Ritz, Karl and J. Six and Strong, Donald and Van der Putten, W.H.} } @article {49911, title = {The significance of carbon-enriched dust for global carbon accounting}, journal = {Global Change Biology}, volume = {18}, year = {2012}, month = {12/2012}, pages = {3275-3278}, chapter = {3275}, abstract = {

Soil carbon stores amount to 54\% of the terrestrial carbon pool and twice the atmospheric carbon pool, but soil organic carbon (SOC) can be transient. There is an ongoing debate about whether soils are a net source or sink of carbon, and understanding the role of aeolian processes in SOC erosion, transport and deposition is rudimentary. The impacts of SOC erosion by wind on the global carbon budget, and its importance for carbon accounting remain largely unknown. Current understanding of SOC losses to wind erosion is based on the assumption that the SOC content of eroded material is the same as that of the parent soils. However, measured enrichment factors for the SOC content of Australian dusts relative to parent soils show that the SOC content of dusts can be up to seven times (by weight) larger than that of source-area soils, with enrichment factors ranging from 1.67 to 7.09.\  Assuming dust emissions from the continent of ~110 Mt yr -l , SOC dust emissions would be 0.13{\textendash}4.65 Mt SOC yr {\textendash}l\  without enrichment but 0.94{\textendash}7.77 Mt SOC yr-l\  with enrichment; which represents an uncertainty of around 60\%.\  Representing SOC enrichment within dust emission models will reduce uncertainty in estimates of the impact of wind erosion on SOC flux and provide an approach for the inclusion of wind erosion processes in carbon accounting systems.

}, doi = {10.1111/j.1365-2486.2012.02780.x}, url = {/files/bibliography/12-038.pdf}, author = {Nicholas Webb and A. Chappell and Craig Strong and Samuel K. Marx and Grant McTainish} } @article {49915, title = {Spatiotemporal patterns of production can be used to detect state change across an arid landscape}, journal = {Ecosystems}, volume = {15}, year = {2012}, month = {01/2012}, pages = {34-47}, chapter = {34}, abstract = {Methods to detect and quantify shifts in the state of ecosystems are increasingly important as global change drivers push more systems towards thresholds of change. Temporal relationships between precipitation and aboveground net primary production (ANPP) have been studied extensively in arid and semiarid ecosystems, but rarely has spatial variation in these relationships been investigated at a landscape scale, and rarely has such information been viewed as a resource for mapping the distribution of different ecological states. We examined the broad-scale effects of a shift from grassland to shrubland states on spatiotemporal patterns of remotely sensed ANPP proxies in the northern Chihuahuan Desert. We found that the Normalized Difference Vegetation Index (NDVI), when averaged across an eight-year period, did not vary significantly between these states, despite changes in ecosystem attributes likely to influence water availability to plants. In contrast, temporal relationships between precipitation and time-integrated NDVI (NDVI-I) modeled on a per-pixel basis were sensitive to spatial variation in shrub canopy cover, a key attribute differentiating ecological states in the region. The slope of the relationship between annual NDVI-I and two year cumulative precipitation was negatively related to, and accounted for 71\% of variation in, shrub canopy cover estimated at validation sites using high spatial resolution satellite imagery. These results suggest that remote sensing studies of temporal precipitation-NDVI relationships may be useful for deriving shrub canopy cover estimates in the region, as well as for mapping other ecological state changes characterized by shifts in long-term ANPP, plant functional type dominance, or both.}, keywords = {aboveground net primary production, Chihuahuan Desert state change, grassland, normalized difference vegetation index, precipitation, remote sensing, shrub encroachment, shrubland}, doi = {10.1007/s10021-011-9490-2}, url = {/files/bibliography/12-003.pdf}, author = {Jebediah C. Williamson and Brandon T Bestelmeyer and Debra C. Peters} } @proceedings {JRN54536, title = {Seasonal distribution of net primary production by functional groups in Chihuahuan Desert, and the role of seasonal precipitation}, volume = {PS 50-117.}, year = {2012}, month = {08/2012}, publisher = {Ecological Society of America Proceeding}, address = {Portland, Oregon}, abstract = {In hot deserts, precipitation is the principal driver for net primary production.~ This study tested two hypotheses regarding aboveground net primary production (ANPP) and the effects of precipitation on ANPP in the Chihuahuan Desert, with emphasis on differences among seasons and among functional groups of species. First, we hypothesized that the majority of annual ANPP occurs in the monsoon season.~ Second, we hypothesized that ANPP is positively correlated to precipitation. The study site, Jornada Basin USDA-LTER site, is located in the northern Chihuahuan Desert where Jul-Sep is the monsoon season during which 53\% of annual rainfall occurs.~ The ANPP and precipitation data were collected at 15 locations in 5 ecosystem types: 2 grassland types and 3 shrubland types (N=3 for each type) during 1990-2010.~ Three seasons were defined: winter (Oct {\textendash} Feb), spring (Mar {\textendash} May), and fall (Jun- Sep). ~ANPP was separated into three plant functional groups: C3 shrubs, C4 perennial grasses, and other plants (C3 and C4 annual forbs and grasses, and perennial forbs). Our results supported the first hypothesis for grasslands, but not for shrublands. On average, 67\% of annual ANPP in grasslands occurred in fall (range: 62-73\%); however, only 49\% of annual ANPP in shrublands occurred in fall (range: 41-58\%).~ Our second hypothesis was supported for some, but not all, functional groups and seasons. For example, in grasslands in general, fall perennial grass production was not related to fall precipitation. In shrublands winter and spring shrub production were high (winter: 5-21\% of annual ANPP, spring: 14-42\%, fall: 20-33\%), but they were not related to precipitation.~ In short, there were significant differences between desert grasslands and desert shrublands in terms of seasonal distribution of ANPP and response of ANPP to seasonal precipitation. ~This provides important information for understanding and projecting the impact of global climate change (e.g., change in seasonality, intensity, and frequency of precipitation) on structure and function of desert ecosystems.}, author = {Jin Yao and Debra C. Peters} } @proceedings {JRN54532, title = {Seasonal distribution of net primary production in Chihuahuan Desert shrublands and grasslands in response to precipitation from 1990-2010}, volume = {p. 42.}, year = {2012}, month = {05/2012}, publisher = {Wildland Shrub Symposium Proceedings}, address = {Las Cruces, NM}, abstract = {In arid and semiarid regions around the world, extensive areas of grasslands have been replaced by shrublands. A better understanding of the ecology of these shrublands compared to historical grasslands would help land managers make decisions for the sustainable provision of ecosystem goods and services. We compared aboveground net primary production (ANPP) and its response to precipitation between shrublands and grasslands in the Chihuahuan Desert, with an emphasis on differences among seasons and among functional groups of species. The study site, Jornada Basin USDA-LTER site, is located in the northern Chihuahuan Desert. The ANPP and precipitation data were collected at 15 locations in 5 ecosystem types: 3 shrubland types and 2 grassland types (N=3 for each type) during 1990-2010.~ Three seasons were defined: winter (Oct {\textendash} Feb), spring (Mar {\textendash} May), and fall (Jun- Sep). ~ANPP was separated into three plant functional groups: shrubs, perennial grasses, and others. The results showed significant differences between shrublands and grasslands in the seasonal pattern of ANPP, and in the relationship between precipitation at different time periods with seasonal ANPP. Compared to grasslands where ANPP was highest in the fall, shrubland ANPP occurred more evenly among all three seasons. For most locations, seasonal precipitation did not explain the most variation in the current season{\textquoteright}s ANPP. The precipitation period explaining the most variation in seasonal ANPP varied among ecosystem types and among locations within each type. These results suggest that other factors, such as soil water content, may be driving seasonal variation in ANPP, and that land management practices may need to be tailored to specific ecosystem types.}, author = {Jin Yao and Debra C. Peters} } @article {49916, title = {Spatial patterns of grasses and shrubs in an arid grassland environment}, journal = {Ecosphere}, volume = {2}, year = {2011}, month = {09/2011}, chapter = {Article 103}, abstract = {In the Chihuahuan Desert of Mexico and New Mexico, shrub invasion is a common problem, and once-abundant grassland ecosystems are being replaced by shrub-dominated habitat. The spatial arrangement of grasses and shrubs in these arid grasslands can provide better insight into community dynamics and can provide information on grass shrub interactions. To better understand the dynamics of the Chihuahuan Desert ecosystem and to provide information regarding the interactions between grasses and shrubs, we examined the spatial patterns of grasses and shrubs in remaining grass-dominated areas, interspersed with some shrubs. We developed 18, 10320 m vegetation distribution plots by mapping the location of all grasses and shrubs on each and repeating the measurements three years later. Spatial patterns were then assessed for each plot using a second-order spatial statistic, Ripley\’s K-function, as well as any observed changes in the spatial patterns over a three-year period. We observed clumped grass distributions, indicating a lack of competition among grasses; random shrub distributions; and even grass distribution with respect to shrub locations, indicating competition between grasses and shrubs. We also observed a tendency for grass distributions to become more even over time, and grasses to become less even with respect to shrub locations over time. These changes occurred during a period of greater than average rainfall, indicating that greater water availability may lead to increased competition among grasses and decreased competition between grasses and shrubs.}, keywords = {arid grasslands, Bouteloua eriopoda, Chihuahuan Desert, grass and shrub interactions, Jornada Experimental Range, prosopis glandulosa, Ripley{\textquoteright}s K-function, shrub expansion, spatial patterns, sporobolus spp.}, doi = {10.1890/ES11-00104.1}, url = {/files/bibliography/11-041.pdf}, author = {Lorelei Alvarez and Howard Epstein and Junran Li and Gregory S. Okin} } @article {49928, title = {Spatial perspectives in state-and-transition models: A missing link to land management?}, journal = {Journal of Applied Ecology}, volume = {48}, year = {2011}, month = {03/2011}, pages = {746-757}, chapter = {746}, abstract = {Conceptual models of alternative states and thresholds are based largely on observations of ecosystem processes at a few points in space. Because the distribution of alternative states in spatially-structured ecosystems is the result of variations in pattern-process interactions at different scales, we argue that data and models need to explicitly consider ecosystem processes in the context of the spatial pattern of drivers, spatial dependence in responses to drivers, and the spatial structure of feedbacks. Here, we review the literature on spatial patterns and processes in the context of state transitions (or regime shifts) and draw upon examples from semiarid ecosystems to illustrate these linkages. We suggest three spatial perspectives be used to expand conceptual state-and-transition (S\&T) models to landscape systems. First, S\&T models should represent how spatial patterns of natural and anthropogenic drivers interact to initiate transitions. This would account for often observed situations wherein contrasting states occur along gradients of disturbance intensity or in different management units. Second, spatial dependence in response to drivers and triggers should be represented. This would help account for observed differences in ecological resilience tied to inherent spatial variation in environmental variables (e.g., soil and landform attributes) that mediate driver effects and lead to variation in the likelihood of state transitions. Third, the nature of feedbacks, how they propagate over time and space, and how they are conditioned by patterns of spatial dependence and drivers should be represented. At fine scales, changes in the nature and intensity of feedbacks may be associated with predictable changes in patch structure (e.g., fragmentation or coalescence processes foreshadowing thresholds). At coarser scales, feedbacks may be associated with the spatial extent and arrangement of land cover states, broad-scale resource redistribution (e.g., wind/water erosion/deposition) or land surface/climate interactions. S\&T conceptual models with a spatial component would make use of readily-obtainable patch-scale data to predict how the likelihood of transitions might vary across landscapes and to forecast changes leading to degradation or recovery. Such predictions would be valuable in the design of monitoring schemes aimed at adjusting management to avert crossing degradation thresholds and to take advantage of environmental conditions required to restore desired states.}, keywords = {Chihuahuan Desert, contagion, Iceland, monitoring, patch dynamics, regime shift, southern Great Plains, spatial dependence, thresholds}, doi = {doi: 10.1111/j.1365-2664.2011.01982.x}, url = {/files/bibliography/11-007.pdf}, author = {Brandon T Bestelmeyer and D. Goolsby and Steven R. Archer} } @proceedings {49930, title = {State-and-transition model archetypes: A global taxonomy of rangeland change}, volume = {IX}, year = {2011}, month = {04/2011}, pages = {60}, address = {Roxario, Argentina}, abstract = {State and transition models (STMs) synthesize science-based and local knowledge to formally represent the dynamics of rangeland and other ecosystems. Mental models or concepts of ecosystem dynamics implicitly underlie all management decisions in rangelands and thus how people influence rangeland sustainability. STMs use a combination of elements, including structured inventory and mapping, historical reconstruction, process-based comparisons and experiments, and local knowledge to develop formal models of ecosystem function. The models describe the mechanisms by which transitions among states occur and thus the interventions needed to achieve or sustain desired states. STMs are very useful tools, but are often difficult to construct. We ask whether we can identify a series of basic, archetypal models globally that could be matched to local ecosystems and assist in the development of local STMs.}, keywords = {conservation practices, ecological sites, monitoring, succession, thresholds}, author = {Brandon T Bestelmeyer and H. Raul Peinetti and Jeffrey E. Herrick and Diego Steinaker and Edgardo Adema} } @article {49933, title = {A site-based approach to delivering rangeland ecosystem services}, journal = {The Rangeland Journal}, volume = {33}, year = {2011}, month = {06/2011}, pages = {99-108}, chapter = {99}, abstract = {Rangeland ecosystems are capable of providing an array of ecosystem services important to the wellbeing of society. Some of these services (e.g. meat, fibre) are transported to markets and their quantity, quality and value are established via a set of widely accepted standards. Other services (e.g. climate mitigation, water quality, wildlife habitat) do not leave the land, but are, in fact, most valuable when they remain in situ. Determining their quantity, quality and value presents a challenge that must be met if there is to be a credible, accessible ecosystem services market for rangelands. In this paper we describe some of the ecosystem services that may be extracted from rangelands, discuss their unique ecological nature and relate those unique ecological properties to soil and vegetation attributes that can serve as a basis for measurement, both quality and quantity. We suggest the use of a soil/vegetation-based system in which similar climate, geomorphology and edaphic properties are grouped into ecological sites based on their response to disturbance. Within each ecological site, a unique state and transition model describes the dynamics of vegetation and soil surface properties, provides state indicators (vegetation structure, soil properties), predicts ecosystem services that may be derived at multiple scales, and organizes information related to management to achieve ecosystem service objectives, including sustainability.}, doi = {10.1071/RJ11006}, url = {/files/bibliography/11-011.pdf}, author = {Joel R. Brown and MacLeod, Neil} } @article {49990, title = {A simple graphical approach to quantitative monitoring of rangelands}, journal = {Rangelands}, volume = {33}, year = {2011}, month = {08/2011}, pages = {6-13}, chapter = {6}, doi = {10.2111/1551-501x-33.4.6}, url = {/files/bibliography/11-023.pdf}, author = {C. Riginos and Jeffrey E. Herrick and Siva R. Sundaresan and Carey Farley and Jayne Belnap} } @proceedings {49989, title = {Simple method for monitoring rangeland health and wildlife habitat}, year = {2011}, month = {04/2011}, address = {Rosario, Argintina}, abstract = {

We describe a monitoring system that requires just a pencil, one page datasheet and a 1-meter stick. Data are collected using the stick at five locations on each of four 25-m transects. Vegetation cover, composition, and horizontal and vertical structure are recorded by marking simple icons on the sheet. The datasheet also allows plant density to be recorded for selected species. The datasheet is designed to allow indicators to be easily calculated on the datasheet. Most indicators require only counting, or multiplication by five. The pattern of circled cover icons on the datasheet also provides a rapid visual representation of vegetation in the 50-m diameter plot. Initial application of the protocols in Kenya and Ethiopia were successful. Workshop participants learned to collect, analyze and interpret data in as little as 3 hours. The datasheet simplifies calculation and interpretation. Standardized indicators allow for comparison across management units.

}, keywords = {methods, rangeland health, rangeland monitoring, wildlife habitat}, author = {C. Riginos and Jeffrey E. Herrick and Siva R. Sundaresan and Carey Farley and Jayne Belnap} } @proceedings {49993, title = {Soil distrubance increases soil microbial enzymatic activity in arid ecoregion}, year = {2011}, month = {08/2011}, publisher = {Nature Proceedings}, address = {Bad Nauheim, Germany}, abstract = {Functional diversity of the soil microbial community is commonly used in the assessment of soil health as it relates to the activity of soil microflora involved in carbon cycling. Soil microbes in different microenvironments will have varying responses to different substrates, thus catabolic fingerprint information of each location-specific community can be obtained. The purpose of this study was to evaluate total-soil enzymatic activity profiles across three disturbance regimes in an arid desert grassland in the Southwestern United States. Microbial enzymatic activity was measured using the MicroResp\™ system, which measures respiration of microbes within whole soil samples supplemented with various carbon sources (simple and polymeric sugars, amino acids, carboxylic acids, and fatty acids). Total bacterial diversity was assessed by 16sRNA pyrosequencing. Microbial activity was greatest and most variable in sites exposed to disturbance (grazing, natural gas extraction). The introduction of disturbance, and therefore enhanced heterogeneity, may drive changes in soils towards higher functional diversity to adapt to the disturbance.}, doi = {http://dx.doi.org/10.1038/npre.2011.6202.1}, url = {/files/bibliography/11-029.pdf}, author = {Schwab, Lori K. and Unc, Adrian and M.E. Lucero} } @conference {50006, title = {Spatial heterogeneity in aboveground net primary production and species richness at multiple scales in the Chihuahuan Desert}, booktitle = {US-International Association for Landscape Ecology}, year = {2011}, month = {04/2011}, address = {Portland, OR}, abstract = {We analyzed patterns in spatial heterogeneity and the processes driving these patterns in two ecosystem properties, aboveground net primary production (ANPP) and species richness, at multiple scales in the Chihuahuan Desert.\  We used long-term data (1990-2009) to examine the importance of a suite of drivers and ecosystem properties to patterns in ANPP and species richness at two spatial scales: patch and landscape unit.\  Three patches were sampled annually within each of five landscape units: upland and playa grasslands, and mesquite, creosotebush, and tarbush shrublands. Spatial heterogeneity at the patch scale was measured as the coefficient of variation across quadrats (n = 48 or 49).\  Spatial heterogeneity at the landscape unit scale was measured as the coefficient of variation across patches.\  At the patch scale, heterogeneity was affected by growth form of the dominant plant species and by precipitation. Grasslands were more homogeneous than shrublands under drought conditions, but shrublands were more homogeneous in wet years. At the landscape unit scale, heterogeneity was mainly affected by variation in distance between patches and variation in precipitation. Because of high spatial heterogeneity across these diverse landscapes, we concluded that estimates of ANPP and species richness from fine scales can not be directly extrapolated to broader scales in the Chihuahuan Desert without accounting for both local and spatial drivers of processes.}, author = {Jin Yao and Debra C. Peters} } @conference {JRN54463, title = {Spatial and temporal free-ranging cow behaviour pre and post-weaning}, booktitle = {4th Grazing Livestock Nutrition Conference}, year = {2010}, month = {07/2010}, address = {Estes Park, CO}, abstract = {

Global positioning system (GPS) technology can be used to study free-ranging cow behaviors. GPS equipment was deployed on each of ten cows ranging in age from 3 to 15 years in order to compare and contrast mean {\textpm} standard errors for pre- and post-weaning travel (m.time-1) in two similar (<= 433 ha) arid rangeland paddocks.\  Data were collected at a rate of one position fix per second between 12 March and 8 April 2009 for a total of 8.7 million raw GPS fixes across both paddocks.\  In addition, all 10 instrumented cows, 5 per paddock, were observed for a total of 32 h across 13 d and their behaviors were recorded on a minute by minute basis during daylight.\  The observational data were used to classify rate of travel (m.min-1) into walking, foraging and stationary behaviors. The observed behavioral data were merged with the GPS data.\  Next the merged data were examined to classify the GPS data by path speed (m.s-1).\  Intervals of 30 s, 60 s, 120 s and 180 s were evaluated to determine the optimum path speed sampling period to discriminate among walking, foraging and stationary behavior.\  The path speed associated with {\textquotedblleft}stationary{\textquotedblright} was due to the inherent variability within the uncorrected GPS data used in this study.\  Regardless of interval chosen, three distinct peaks were observed.\  Within the ranges evaluated, longer sampling intervals (180 s) appeared to show better peak definition, especially for those peaks associated with foraging (0.10 m.s-1) and {\textquotedblleft}stationary{\textquotedblright} (0.03 m.s-1) behaviors.\  Shorter sampling periods (30 s) produced smother curves having less distinct peaks, probably as a result of more samples.\  The fastest movement had a peak at 1.00 m.s-1 and corresponded to periods when the cows were observed to be traveling between points on the landscape. A 1.00 m.s-1 rate of travel is roughly 2.2 miles per hour, a speed used to manually gather these cows.\  Subsequent analyses were performed using 60 s sampling intervals as a compromise for well defined peaks and troughs, smoothness of the curve, and relatively high frequency counts at the high speed end of the distribution. Overall, mean cow travel increased post-weaning over 5 d in Paddock 10B from 1,428 {\textpm} 92.6 m.d-1 to 1,955 {\textpm} 143.4 m.d-1 and over 8 d post-weaning in Paddock 14A from 1,166 {\textpm} 105.8 m.d-1\  to 1,509 {\textpm} 92.0 m.d-1. Mean travel in the two paddocks during foraging both pre- and post-weaning varied within a day but not in an identical manner even though the two paddocks were similar in size and topography.\  Among four 6 h time intervals foraging travel decreased following weaning between 0600 h (6 am) and noon and between 1800 h (6 pm) and midnight in both paddocks while travel associated with foraging increased between noon and 1800 h (6 pm) in both paddocks.\  Foraging travel between midnight and 0600 h (6 am) decreased in Paddock 10B following weaning (64 {\textpm} 5.6 m.6h-1 vs 42 {\textpm} 4.4 m.6h-1) but increased in Paddock 14A (24 {\textpm} 6.6 m.6h-1 vs 60 {\textpm} 7.3 m.6h-1) during this same time interval following weaning.\  Differences in foraging travel between midnight and 0600 h (6 am) in the two paddocks may have resulted from several factors including: the number of non-instrumented cows being different in the two paddocks, different weaning dates 13 d apart, and a different spatial distribution of cows within each paddock.\  Furthermore, GPS data were lost possibly due to battery failure.\  Only one 24 h period of data were lost from one cow in Paddock 10B (post-weaning) compared to loss of GPS data from two and three of the five cows for 24 h pre- and post-weaning, respectively, in Paddock 14A.\  Further data analysis evaluating tortuosity of travel (a metric that relates path speed or the summation of distances between each of 60 positions within a minute to displacement speed the distance between only the first position and the 60th position within a minute) appears promising to further characterize free-ranging cow travel. pg 192.
.

}, author = {D.M. Anderson and Craig Winters and Marek Doniec and Detweiler, C. and D. Rus and B. Nolen} } @proceedings {50018, title = {Spatial autocorrelation of shrub cover in an arid rangleand ecosystem from 1937-2008}, year = {2010}, abstract = {The proliferation of trees and shrubs in grassland and savanna ecosystems has been widely observed, although future trajectories remain difficult to ascertain. Spatial manifestations of shrub proliferation bear relevance on surface hydrology and the spread of disturbance. We quantify changes in spatial autocorrelation in shrub cover in an arid grassland ecosystem to test the validity of a conceptual framework highlighting the role of shrub patch dynamics in the shrub encroachment process. We build upon the framework to suggest how the encroachment and stabilization phases manifest spatially. We suggest that indicators of spatial autocorrelation illustrate where local interactions are more prevalent, thereby functioning as an indicator of biotic regulation and stabilization in shrub cover. We analyzed binary maps of shrub cover from 1937 to 2008 derived from time series aerial photography. Spatial analyses entailed resampling 1-m depictions of shrub patches to percent shrub cover within 20-m X 20-m quadrats to examine the spatial autocorrelation with Moran\’s I using GeoDa software. We decomposed the global index of spatial association into contributions from local neighborhoods using Local Indicator of Spatial Association, which quantifies the extent to which cells are similar to or different from their neighbors. Shrub cover in 1937 was highly heterogenous and became more dispersed and less patchy over the 71 years. As shrub cover increased, it became increasingly positively autocorrelated with Moran\’s I increasing from 0.383 in 1937 to 0.742 in 2008. We found no clear evidence of self-organization, although we did detect clear evidence of local effects that resulted in broad scale patterns with hot-spots of low and high cover. Assessment of shrub patch dynamics (i.e., coalescence, fragmentation of patches) is on-going to identify mechanisms associated with changes in autocorrelation.}, keywords = {remote sensing, shrub cover}, author = {Dawn M. Browning and Andrea S. Laliberte and A. Rango and Moreno, A.} } @conference {50017, title = {Species{\textendash}specific contributions to moderate resolution vegetation indices derived from sub-decimeter aerial photography {\textendash} Prospects for phenological monitoring}, booktitle = {American Society for Photogrammetry and Remote sensing Proceedings}, year = {2010}, month = {04/2010}, address = {San Diego, California}, abstract = {

High spatial heterogeneity in ground cover, large amounts of exposed bare soil, and modest cover from shrubs and grasses in arid and semi-arid ecosystems challenge the integration of field observations of phenology and remotely sensed data to monitor changes in land surface phenology. This research conducted at the Jornada Basin Long-Term Ecological Research (LTER) site in southern New Mexico capitalizes on object-based classification of sub-decimeter (4 cm) aerial photography to examine species-specific contributions to vegetation index values calculated across a range of grain sizes. Drawing on established field protocols for reproductive phenology, sub-decimeter imagery (4 cm), and object-based image analysis, we explore the relationship between field phenology and vegetation index values and quantify the contribution of individual species to spectral vegetation index values derived from 4 cm imagery aggregated incrementally to 30 m spatial resolution. Color-infrared imagery from a digital mapping camera was collected June 2007 across 15 LTER study sites that transect five distinct vegetation communities along a continuum of grass to shrub dominance. Object-based image analysis of 4 cm imagery provides a detailed depiction of ground cover and allows us to extract species-specific contributions to spectral vegetation indices. The ability to discern species- or functional-group contributions to remotely sensed signals of vegetation greenness can greatly enhance the design of field sampling protocols for phenological research. Furthermore, imagery from unmanned aerial vehicles (UAV) is a cost-effective and increasingly available resource and generation of UAV mosaics has been accomplished so that larger study areas can be addressed. This technology can provide a robust basis for scaling relationships for phenology-based research applications.

}, author = {Dawn M. Browning and Andrea S. Laliberte and A. Rango} } @article {50019, title = {Southwest transformation: eras of growth and land change in Las Cruces, New Mexico}, journal = {Southwestern Geographer}, volume = {14}, year = {2010}, pages = {57-87}, abstract = {The United States Southwest is the incubator of the country\&$\#$39;s fastest growing urban landscapes, but few studies have quantified urbanization in the region. Using geospatial and archival research techniques our objectives are to assess rates, patterns, and drivers of land change in Las Cruces, New Mexico between 1955 and 2007, thereby stimulating more dialogue on the transformation of Southwestern landscapes. Our results suggest that Las Cruces may be on a path toward urban immensity. During the last fifty years, the city\&$\#$39;s population has grown at an average annual rate of 4.5\%. The landscape became transformed concomitantly: almost 30\% of the study area was converted from farm- and rangeland to residential and urban development. The pattern of development changed over time. Between 1955 and 1980, farm- and rangeland were perforated and dissected to make room for housing and infrastructure developments, causing the landscape to become increasingly fragmented and heterogeneous. Between 1980 and 2007, fragmentation continued, but was replaced in some areas by the shrinking and attrition of left-over farm- and rangeland and by the coalescence and growth of residential and urban clusters. Major drivers of growth included natural gain; in-migration from Mexico and the United States due to Sun Belt climate, federal employment, and other factors; as well as the conversion of a large government land base to private development. Absent viable land conservation programs, the formerly little known community of Las Cruces may face the same growth trajectory as major Southwest urban centers, slowed only temporarily by the current recession. land change/ urbanization/ landscape fragmentation/ population growth/ southwest/ Las Cruces}, keywords = {land change, landscape fragmentation, Las Cruces, population growth, Southwest, urbanization}, author = {M. Buenemann and J. Wright} } @article {50023, title = {Soil processes and properties that distinguish ecological sites and states}, journal = {Rangelands}, volume = {32}, year = {2010}, month = {12/2010}, pages = {9-15}, chapter = {9}, abstract = {

Differences in ecological sites, and sometimes ecological states, are ultimately due to differences in soil properties and processes within a climatic zone. Soil properties are features of a soil, such as soil texture or soil depth.\  Soil processes are a series of actions in the soil that bring about a result, for example, water percolating into the soil that determines soil water amounts. Measured relationships between soil properties and soil processes allow us to estimate soil processes given information on a set of soil properties and other variables, such as rainfall amounts. For example, we can predict the rate at which water will percolate into a soil profile if we have data on soil properties such as texture, soil structure, bulk density, and organic matter. How do we determine which soil properties and processes differ among ecological sites or ecological states?\  This is typically done by observing relationships between soils and the plant communities occurring on them.\  We inventory plant communities and soil properties within a climatic zone and look for statistical relationships among them. We then draw on research to infer the soil processes that occur and develop hypotheses about how those processes explain plant community patterns.\  Although soil and landform properties are used to describe the characteristics of ecological sites, it is the soil processes that are controlled by the properties that actually cause differences between ecological sites. Soil processes explain why ecological sites (and sometimes states) differ. The goal of this article is to equip developers and users of ecological site descriptions with a basic understanding of how differences in soils arise, the relationship between soil maps and ecological sites, and how soil properties affect soil processes to create differences among ecological sites and states. Our hope is that this understanding can be used to guide data collection and help develop narratives to explain the properties of ecological sites and states.

}, doi = {10.2111/RANGELANDS-D-10-00090.1}, url = {/files/bibliography/10-043.pdf}, author = {Danielle Duni and Brandon T Bestelmeyer and A.J. Tugel} } @article {50022, title = {Spatial and temporal patterns of water availability in a grass-shrub ecotone and implications for grassland recovery in arid environments}, journal = {Ecohydrology}, volume = {3}, year = {2010}, pages = {55-67}, abstract = {

Encroachment of woody shrubs into historic desert grasslands is a major problem throughout the world. Conversion of grasslands to shrub-dominated systems may result in significant alteration of biogeochemical processes and reduced resource availability in shrub interspaces, making grassland recovery difficult. Soil petrocalcic horizons, which are common in arid and semiarid regions globally, have been shown to dramatically alter plant water availability. To assess how soil water dynamics are affected by woody encroachment in petrocalcic soils under contrasting precipitation patterns, we conducted a three year replicated study in a mixed shrub-grass system measuring soil water in unvegetated interspaces and under mesquite canopies. Plots were instrumented with TDR moisture probes, both above and within the soil petrocalcic horizon. Soils in both vegetation strata maintained large increases in available water content for several months during a wetter than normal winter and summer (increases of 0.08 to 0.16 m3 m-3). Interspace soils absorbed significantly greater quantities of water during the winter and retained more water into the spring than soils under shrubs. In contrast, soils under shrubs initially absorbed greater volumes of water during and following summer rains. Differing seasonal dynamics were attributed to interactions between the unique properties of soils with petrocalcic horizons and canopy induced variability in evapotranspiration. Observed patterns of plant available water do not support the hypothesis of greater resource availability under shrubs. Similar or greater water availability in shrub interspaces indicates that concentration of soil water under shrubs may not be a process limiting grass recovery on these soils.

}, keywords = {biogeochemical, grass-shrub, journal, patterns, shrub-dominated, spatial, temporal}, doi = {10.1002/eco.94}, url = {/files/bibliography/10-01.pdf}, author = {Danielle Duni and K. A. Snyder and Jeffrey E. Herrick} } @article {50021, title = {Spatial and temporal variability of plant-available water in calcium carbonate-cemented soils and consequences for arid ecosystem resilience}, journal = {Oecologia}, volume = {163}, year = {2010}, note = {August 14, 2008-Ecology; resubmitted to Oecologia 3-19-2009 w/new title}, pages = {215-226}, chapter = {215}, abstract = {

Increased variability in precipitation, including frequency of drought, is predicted for many arid and semiarid regions of the world. The ability of soils to retain water can increase resilience by buffering vegetation communities against precipitation extremes. Little is known, however, about water retention by carbonate cemented soil horizons, which occur extensively in arid and semiarid ecosystems. It has been speculated that they may significantly modify vertical and temporal distribution of plant-available water (PAW). To investigate this hypothesis, PAW was monitored at three sites in a mixed shrub-grass community in southern New Mexico, USA, across soils with differing degrees of carbonate horizon development: no carbonate horizon, a partially cemented calcic horizon, and a continuously cemented petrocalcic horizon. Results are presented from three years that included extremely dry and wet periods. Calcic and petrocalcic horizons absorbed and retained significantly greater amounts of PAW for several months following an extremely wet winter and summer compared to the non-carbonate soil. Following a wet summer, petrocalcic horizons retained very high PAW (16 to 18\% volumetric or ~72 to 80\% of soil water holding capacity) through early spring of the following year, more than double the PAW retained by similar depths in the non-carbonate soil. Drying dynamics indicate calcic and petrocalcic horizons release stored water into the grass rooting zone during growing seasons following extreme events. Water dynamics of calcic and petrocalcic horizons during extreme events provide a mechanism to explain previous observations that perennial grasses exhibit greater resilience to drought when high carbonate horizons occur at shallow depths (\< 50 cm). Water holding capacity of the entire profile, including rock-like material such as calcium carbonate, should be considered when evaluating the potential resilience of vegetation communities to disturbance, including the increased variability in precipitation expected to occur as a result of global climate change.

}, keywords = {calcic, Chihuahuan Desert, climate change, desert grassland, ecosystem, horizon, Petrocalcic, precipitation}, doi = {10.1007/s00442-009-1530-7}, url = {/files/bibliography/10-03.pdf}, author = {Danielle Duni and Jeffrey E. Herrick and Curtis H. Monger} } @conference {JRN54454, title = {A suite of tools for monitoring and assessing impacts of road networks and off-road vehicle activity on rangelands }, booktitle = {63rd Society for Range Management Annual Meetings}, year = {2010}, month = {02/2010}, publisher = {Sociiety for Range Management}, organization = {Sociiety for Range Management}, address = {Denver, CO}, abstract = {

Despite increasing amounts of transportation related activities on rangelands globally, few tools exist for assessing and monitoring impacts of roads, road networks and off-road vehicle traffic. This is in part due to an historical emphasis on grazing issues in rangelands and the complexity of monitoring and assessing impacts of roads and vehicles on rangeland health and productivity. We present strategies for applying new and existing tools to monitoring and assessment of road and off-road vehicle impacts at multiple spatial scales. Tools described include an adaptation of Interpreting Indicators of Rangeland Health, a checklist for describing hydrologic impacts, LIDAR analyses, laser rangefinders, and various types of penetrometers. We demonstrate how a currently available online application can help select appropriate assessment and monitoring methods and design cost-effective sampling systems. The suite of tools presented can potentially greatly increase our ability to detect road and vehicle associated impacts at multiple spatial scales, filling an important knowledge gap necessary for adaptive management of road and vehicle impacted rangelands. Abstract $\#$ PC-24.

}, author = {Danielle Duni and Jeffrey E. Herrick and Jason W. Karl and Justin Van Zee} } @proceedings {50037, title = {Spatial dependence of predictions from image segmentation: a methods to determine appropriate scales for producing land-management information}, volume = {No. XXXVIII-4/C7}, year = {2010}, address = {Ghent, Belgium}, abstract = {A challenge in ecological studies is defining scales of observation that correspond to relevant ecological scales for organisms or processes. Image segmentation has been proposed as an alternative to pixel-based methods for scaling remotely-sensed data into ecologically-meaningful units. However, to date, selection of image object sets has been largely subjective. Changing scale of image segmentation affects the variance and spatial dependence (amount and range of spatial autocorrelation) of measured variables, and this information can be used to determine appropriate levels of image segmentation. Our objective was to examine how scaling via image segmentation changes spatial dependence of regression-based predictions of landscape features and to determine if these changes could identify appropriate segmentation levels for a given objective. We segmented an Ikonos image for southern Idaho (USA) into successively coarser scales and evaluated goodness-of-fit and spatial dependence of regression predictions of invasive western juniper (Juniperus occidentalis) density. Correlations between juniper density estimates and imagery increased with scale initially, but then decreased as scale became coarser. Scales with highest correlations generally exhibited the most spatial dependence in the regression predictions and residuals. Aggregating original juniper density estimates by image objects changed their spatial dependence, and the point at which spatial dependence began to diverge from the original observations coincided with the highest correlations. Looking at scale effects on spatial dependence of observations may be a simple method for selecting appropriate segmentation levels. The robustness of ecological analyses will increase as methods are devised that remove the subjectivity of selecting scales.}, keywords = {geostatistics, image segmentation, scale, spatial dependence, variogram}, url = {/files/bibliography/10-047.pdf}, author = {Jason W. Karl and Andrea S. Laliberte and A. Rango} } @article {50040, title = {Spatial dependence of predictions from image segmentation: A variogram-based method to determine appropriate scales for producing land-management information}, journal = {Ecological Informatics}, volume = {5}, number = {3}, year = {2010}, pages = {194-202}, abstract = {

A significant challenge in ecological studies has been defining scales of observation that correspond to the relevant ecological scales for organisms or processes of interest. Remote sensing has become commonplace in ecological studies and management, but the default resolution of imagery often used in studies is an arbitrary scale of observation. Segmentation of images into objects has been proposed as an alternative method for scaling remotely-sensed data into units having ecological meaning. However, to date, the selection of image object sets to represent landscape patterns has been largely subjective. Changes in observation scale affect the variance and spatial dependence of measured variables, and may be useful in determining which levels of image segmentation are most appropriate for a given purpose. We used observations of percent bare ground cover from 346 field sites in a semi-arid shrub-steppe ecosystem of southern Idaho to look at the changes in spatial dependence of regression predictions and residuals for 10 different levels of image segmentation. We found that the segmentation level whose regression predictions had spatial dependence that most closely matched the spatial dependence of the field samples also had the strongest predicted-to-observed correlations. This suggested that for percent bare ground cover in our study area an appropriate scale could be defined. With the incorporation of a geostatistical interpolator to predict the value of regression residuals at unsampled locations, however, we achieved consistently strong correlations across many segmentation levels. This suggests that if spatial dependence in percent bare ground is accounted for, a range of appropriate scales could be defined. Because the best analysis scale may vary for different ecosystem attributes and many inquiries consider more than one attribute, methods that can perform well across a range of scales and perhaps not at a single, ideal scale are important. More work is needed to develop methods that consider a wider range of ways to segment images into different scales and select sets of scales that perform best for answering specific management questions. The robustness of ecological landscape analyses will increase as methods are devised that remove the subjectivity with which observational scales are defined and selected.

}, url = {/files/bibliography/10-019.pdf}, author = {Jason W. Karl and Maurer, Brain A.} } @article {50038, title = {Spatial Predictions of Cover Attributes of Rangeland Ecosystems Using Regression Kriging and Remote Sensing}, journal = {Rangeland Ecology \& Management}, volume = {63}, number = {3}, year = {2010}, pages = {335-349}, abstract = {

Sound rangeland management requires accurate information on rangeland condition over large landscapes. A commonly-applied approach to making spatial predictions of attributes related to rangeland condition (e.g., shrub or bare ground cover) from remote sensing is via regression between field and remotely-sensed data. This has worked well in some situations but has limited utility when correlations between field and image data are low and does not take advantage of all information contained in the field data. I compared spatial predictions from generalized least-squares (GLS) regression to a geostatistical interpolator, regression kriging (RK), for three rangeland attributes (percent cover of shrubs, bare ground, and cheatgrass [Bromus tectorum L.]) in a southern Idaho study area. The RK technique combines GLS regression with spatial interpolation of the residuals to improve predictions of rangeland condition attributes over large landscapes. I employed a remote-sensing technique, object-based image analysis (OBIA), to segment Landsat 5 Thematic Mapper images into polygons (i.e., objects) because previous research has shown that OBIA yields higher image-to-field data correlations and can be used to select appropriate scales for analysis. Spatial dependence, the decrease in autocorrelation with increasing distance, was strongest for percent shrub cover (samples autocorrelated up to a distance [i.e., range] of 19,098 m), but present in all three variables (range of 12,646 m and 768m for bare ground and cheatgrass cover, respectively). As a result, RK produced more accurate results than GLS regression alone for all three attributes when predicted versus observed values of each attribute were measured by leave-one-out cross-validation. The results of RK could be used in assessments of rangeland conditions over large landscapes. The ability to create maps quantifying how prediction confidence changes with distance from field samples is a significant benefit of regression kriging and makes this approach suitable for landscape-level management planning.

}, doi = {10.2111/REM-D-09-00074.1}, url = {/files/bibliography/10-016.pdf}, author = {Jason W. Karl} } @article {50046, title = {A simple method to estimate threshold friction velocity in the field}, journal = {Geophysical Research Letters}, volume = {37}, number = {L10402}, year = {2010}, pages = {1-5}, abstract = {This study provides a fast and easy-to-apply method to estimate threshold friction velocity (TFV) of wind erosion in the field. Wind tunnel experiments and a variety of ground measurements including air gun, pocket penetrometer, torvane, and roughness chain were conducted in Moab, Utah and cross-validated in the Mojave Desert, California. Patterns between TFV and ground measurements were examined to identify the optimum method for estimating TFV. The results show that TFVs were best predicted using the air gun and penetrometer measurements in the Moab sites. This empirical method, however, systematically underestimated TFVs in the Mojave Desert sites. Further analysis showed that TFVs in the Mojave sites can be satisfactorily estimated with a correction for rock cover, which is presumably the main cause of the underestimation of TFVs. The proposed method may be also applied to estimate TFVs in environments where other non-erodible elements such as postharvest residuals are found.}, url = {/files/bibliography/10-09.pdf}, author = {Junran Li and Gregory S. Okin and Jeffrey E. Herrick and Seth M. Munson and M. Miller and Jayne Belnap} } @article {50053, title = {Soil-vegetation-climate interactions in arid landscapes: Effects of the North American monsoon on grass recruitment}, journal = {Journal of Arid Environments}, volume = {74}, year = {2010}, pages = {618-623}, abstract = {

We used a daily time step, multi-layer simulation model of soil water dynamics to integrate effects of soils, vegetation, and climate on the recruitment of Bouteloua eriopoda (black grama), the historically dominant grass in the Chihuahuan Desert. We simulated landscapes at the Jornada ARS-LTER site with heterogeneous soil properties to compare: (1) a grass-dominated landscape in 1858 with the current shrub-dominated landscape (i.e., a change in vegetation structure), and (2) the current shrub-dominated landscape with future landscapes over a range of climate scenarios associated with the North American monsoon (i.e., a change in climate). A historic shift from high productivity grasslands to low productivity shrublands decreased simulated recruitment for most of the site; the amount of reduction depended on location-specific soil properties and changes in production. In some cases, soil properties interacted with vegetation structure: soils high in clay content maintained high recruitment even with a decrease in production. Wetter summers would increase recruitment in all vegetation types. Drier summers below 25\% of current rainfall would decrease recruitment to negligible values (\< 0.03) throughout the landscape. We used our results to identify the conditions where recruitment of B. eriopoda is possible with and without significant modifications to soil and vegetation.

}, keywords = {black grama, Bouteloua eriopoda}, doi = {10.1016/j.jaridenv.2009.09.015}, url = {/files/bibliography/10-014.pdf}, author = {Debra C. Peters and Jeffrey E. Herrick and Curtis H. Monger and C. Huang} } @proceedings {JRN54483, title = {Sensitivity of the snowmelt runoff model to underestimates of remotely sensed snow covered area}, year = {2010}, month = {07/2010}, pages = {WEP2.PL.10}, address = {Honolulu, HI}, abstract = {

Three methods for estimating snow covered area (SCA) from Terra MODIS data were used to derive conventional depletion curves for input to the Snowmelt Runoff Model (SRM). We compared the MOD10 binary and fractional snow cover products and a method for estimating sub-pixel snow cover using spectral mixture analysis (SMA). All three methods underestimated SCA and this contributed to underestimates in runoff modeled by SRM. The closest relationship between measured and computed runoff was achieved when SRM was run with conventional depletion curves derived from the MODIS binary snow cover product (R2 \ = 0.91). Although the MODIS fractional snow cover product and SMA did not perform as well as the binary snow cover product (R2 \ = 0.70 and R2 \ = 0.72 respectively) we anticipate that either of these methods may be reworked to better account for forest cover in our study area and so improve SCA estimates.

}, keywords = {snow covered area, snowmelt runoff model, Terra MODIS}, url = {/files/bibliography/10-026.pdf}, author = {Caitriana Steele and A. Rango and D. K. Hall and M. Bleiweiss} } @conference {50070, title = {The spatial pattern of transition (spot): linking pattern, process, and scale to state-and-transition models}, booktitle = {62nd Society for Range Mangement Annual Meeting}, year = {2009}, month = {February 8-12, 2}, pages = {06-11}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Albuquerque, NM}, abstract = {Field implementation of conceptual state-and-transition models will benefit from explicit representations of spatial patterns of vegetation, soils and topography and the hydrological/eolian processes that link them. Here, we introduce the concept "spatial pattern of transition{\textquotedblright} (SPOT) as a means to understand the interrelationships and feedbacks among vegetation and soil spatial patterns, changes in those patterns over time, and the ecological processes governing that change. Patterns can vary with spatial scale and include vegetation patches in a matrix of bare ground or mosaics of alternative states or plant communities. Key concurrent processes include those affecting surface and subsurface hydrology, eolian transport, resource availability and plant response to stress and disturbance. We review the literature and our own work to establish general approaches to and insights from SPOT. First, we show that SPOT can be observed at multiple scales from remotely-sensed imagery and has been experimentally investigated and mathematically modeled. Second, we argue that SPOT is a consequence of three interacting factors: a) inherent, relative stable heterogeneity in soils, topography and geomorphology, b) disturbance processes such as grazing or fire, and c) feedbacks among plant attributes, surface soil properties, and material fluxes. Third, we show general classes of SPOT that are reliably associated with soil-geomorphic settings and climate zones. Finally, we demonstrate the consequences of SPOT for the development and practical use of state-and-transition models. In particular, we show that differences in SPOT influence (i) the scale at which state-and-transition models should defined, (ii) the ecosystem attributes we need to measure to define thresholds and monitor change, and hence, (iii) the appropriate spatial scale and frequency of observation.}, keywords = {SPOT, SRM, state and transition}, author = {Brandon T Bestelmeyer and D. Goolsby and Steven R. Archer} } @conference {JRN54456, title = {Spatial patterns in alternative states and thresholds: A missing link for management of landscapes?}, booktitle = {10th Biennial Conference for Research on the Colorado Plateau}, year = {2009}, month = {10/2009}, address = {Flagstaff, AZ}, abstract = {

The detection of threshold dynamics (and other dynamics of interest) would benefit from explicit representations of spatial patterns of disturbance, spatial dependence in responses to disturbance, and the spatial structure of feedbacks in the design of monitoring and management strategies. Spatially-structured ecosystems at landscape scales tend to exhibit signals of each of these processes and their interactions. The spatial pattern of disturbance is determined by natural or anthropogenic processes associated with land use. In the latter case, management units and resource use gradients within units often feature different states or indications of threshold risk. Spatial dependence in disturbance response accounts for differences in resilience caused by static environmental variations including soil and landform attributes. These factors determine the effect of disturbance on resource availability and species populations underlying transitions. The patterning of spatial dependence is detected via soil sampling and maps. Finally, the spatial structure of feedbacks accounts for how the initial state change in a location propagates over time and space, conditioned by the pattern of spatial dependence and disturbance. At fine scales, feedbacks may be detected via predictable changes in patch structure (e.g., fragmentation processes prior to crossing soil erosion thresholds). At broader scales, feedbacks may emerge between the distribution of states and broad-scale sediment redistribution (e.g., wind erosion) or even climate. We suggest that these three spatial patterns should be the basis for expanding conceptual state-and-transition models to landscape systems. These new conceptual models would contain predictions about how the likelihood of transition varies across a landscape as well as the patch-scale changes leading to, and determining the reversibility of, transitions. Both sets of predictions would be valuable guides in the design of monitoring to manage thresholds. A hierarchical approach to monitoring featuring ground-based observations coupled to remote-sensing is generally required.\  Pg. 40.

}, author = {Brandon T Bestelmeyer and D. Goolsby and Steven R. Archer} } @article {50071, title = {State-and-Transition models for heterogeneous landscapes: A strategy for development and application}, journal = {Rangeland Ecology and Management}, volume = {62}, year = {2009}, month = {01/2009}, pages = {1-15}, abstract = {

Interpretation of assessment and monitoring data requires information about reference conditions and ecological resilience. Reference conditions used as benchmarks can be specified via potential-based land classifications (e.g., ecological sites) that describe the plant communities potentially observed in an area based on soil and climate. State-and-transition models (STMs) coupled to ecological sites can specify indicators of ecological resilience and thresholds. Although general concepts surrounding STMs and ecological sites have received increasing attention, strategies for their data-driven development have not. In this paper, we outline concepts and a practical approach to potential-based land classification and STM development. Quantification emphasizes inventory techniques readily available to natural resource professionals and that can reveal processes interacting across spatial scales. We recommend a sequence of 8 steps for the co-development of land classes and STMs including 1) creation of initial ecological site concepts and STMs based on literature and workshops; 2) extensive, low-intensity traverses to assist in generating initial concepts and to plan inventory; 3) development of a spatial hierarchy for sampling based on climate, geomorphology, and soils; 4) stratified medium-intensity inventory of plant communities and soils across a broad extent and with large sample sizes; 5) storage of plant and soil data in a database; 6) model-building and analysis of inventory data to test initial concepts; 7) support and/or refinement of concepts; and 8) high-intensity characterization and monitoring of states. Second, we offer a simple example of how data assembled via our sequence can be used to refine ecological site classes and STMs. The linkage of inventory to expert knowledge and site-based mechanistic experiments and monitoring provides a powerful means for specifying management hypotheses and, ultimately, promoting resilience in grassland, shrubland, savanna and forest ecosystems.

}, keywords = {assessment, ecological resilience, monitoring, quantitative, state-and-transition}, doi = {10.2111/08-146}, url = {/files/bibliography/09-004.pdf}, author = {Brandon T Bestelmeyer and A.J. Tugel and G. Peacock and D. Robinett and P. L. Shaver and Joel R. Brown and Jeffrey E. Herrick and H. Sanchez and Kris Havstad} } @article {50093, title = {Soil distrubance by native animals along grazing gradients in an arid grassland}, journal = {Journal of Arid Environments}, volume = {73}, year = {2009}, month = {08/2009}, pages = {1144-1148}, chapter = {1144}, abstract = {

Domestic grazing animals that congregate around watering points in arid rangelands create clearly defined trampling-induced grazing gradients. Grazing and trampling alter soil and vegetation condition, often leading to substantial reductions in ecological function. We measured foraging pits and mounds created by native soil foraging animals over 12 months at three watering points in a Chihuahuan Desert grassland, and hypothesized that the density and cover of their disturbances would increase with increasing distance from water. We recorded an average of 3756 disturbances ha_1 and cover of 34.18 m2 ha_1 across the grazing gradients, which comprised mainly pits (43\%) and mounds (25\%) of heteromyid rodents, ants and spiders. Soil turnover was estimated at 1.43 m3 ha_1. We detected no differences in density, cover, soil volume or composition of disturbances in relation to distance from water, but there were significant, though ill-defined, differences across the five sampling periods, with generally more activity in the warm\–wet months. Small animal-created mounds and pits are important sources of soil and sinks for litter within grazing gradients, and may represent the only sites where plants can establish given a relaxation in grazing pressure.

}, doi = {10.1016/j.jaridenv.2009.06.005}, url = {/files/bibliography/09-026.pdf}, author = {D.J. Eldridge and Walter G. Whitford} } @article {50095, title = {Synthesis and assessment product 4.2: Tresholds of climate change in ecosystems}, year = {2009}, month = {2009 January}, publisher = {USGS}, abstract = {

In the past three decades, climate change has become a pronounced driver of ecosystem change. Changes in phenology, range shift of species, and increases in disturbances such as wildfires have all reflected ecosystem scales responses to a warming biosphere. There have also been abrupt, nonlinear changes in ecosystems where the level of response to incremental increases in temperature have suddenly changed trajectories. These thresholds of ecosystem change are not well understood but are potentially critical to adaptation strategies for managing natural resources in a rapidly changing world. This synthesis is intended to evaluate the current state of understanding of thresholds and to recommend possible actions to improve knowledge and adjust management priorities even with incomplete understanding of what drives thresholds of change and when they will occur.

}, keywords = {assessment, ecosystem, government publication, synthesis, threshold}, url = {/files/bibliography/09-005.pdf}, author = {Fagre, D.B. and Charles, C.W. and C.D. Allen and Birkeland, C. and F.S. Chapin III and Peter M. Groffman and Guntenspergen, G.R. and A. K. Knapp and A. D. McGuire and Mulholland, J.P. and Debra C. Peters and Roby, D.D. and Sugihara, G.} } @conference {50099, title = {Shrub expansion in northern Chihuahuan Desert grasslands: Spatial patterns of transition and biophysical constraints}, booktitle = {62nd Society for Range Management Annual Meeting}, year = {2009}, month = {February 8-12, 2}, pages = {24-4}, address = {Alb., NM}, abstract = {Among the greatest contemporary threats to the structure, function and biological diversity of desert grassland and shrub savanna ecosystems of the southwestern United States is the displacement of mesophytic grasses by xerophytic woody plants. Through a combination of field sampling and spatial modeling we sought to create a predictive understanding of the biophysical conditions under which grasslands are converted to shrublands. We asked: What are the physiographic settings of persistent grass or shrub patches and what environmental factors contribute to their persistence? In communities that are a mosaic of grass and shrub patches, which of these are stable and which are in the process of transitioning to shrub dominance? We characterized landscape-scale perennial plant cover across grassland-to-shrubland gradients within the Jornada Basin near Las Cruces, NM. Changes in shrub and perennial grass patch structure and distribution were quantified using time-series aerial photography (1940s-2000s). Soil was characterized to 150 cm or to restrictive calcium carbonate horizon and the relationships between perennial plant assemblages and soil characteristics were explored using multivariate statistics. Field survey and aerial photography data were then used to develop a model of patch structure dynamics focused on characterizing patterns of vegetation structure and cover that indicate future shifts in shrub-grass abundance. Remnant grass patches were associated with petrocalcic and argillic horizons. Expansion of shrub patches was dependent on local soil characteristics and the context of the surrounding landscape (e.g., landform and adjacent vegetation structure). The signatures of soils and landscape position can be used to distinguish at-risk areas from areas with high, inherent grassland or savanna resilience.}, keywords = {mesophytic, savanna, shrub, SRM, xerophytic}, author = {D. Goolsby and Brandon T Bestelmeyer and Steven R. Archer} } @conference {50098, title = {Spatial and ecological processes in grassland-to-shruland transitions in the Chihuahuan Desert}, booktitle = {Ecological Society of America Abstracts}, year = {2009}, month = {August 2009}, pages = {PS 32-115}, address = {Albuquerque, NM}, abstract = {Grass to shrubland conversions have been widely reported in drylands world wide, but remain poorly understood. Knowledge of ecosystem spatial properties and the environmental constraints underlying landscape pattern is crucial to determining why shrublands have replaced grasslands in some areas and not others as well as predicting where such transitions may be most likely to occur in the future. A useful framework for understanding patterns of grassland-to-shrubland transitions consists of three interacting concepts: 1) direct impacts 2) spatial heterogeneity of underlying constraints, and 3) spatial variation in process feedbacks. The application of this framework allows spatial modeling of landscape change to be appropriately constrained at various spatial/temporal scales ranging from those operating at the scale of plants to those operating at the scale of landforms. Mesquite (Prosopis glandulosa) invasion of grasslands in southern New Mexico and the proliferation of juniper (Juniperus monosperma) in pinion-juniper savanna in central New Mexico are two cases where conceptual models of spatial influences on state transitions may be developed and evaluated. Repeat air photography and remotely sensed images from the Jornada LTER and Chupadera Mesa were analyzed to quantify landscape-scale spatial patterns of transition at decadal time-scales. Patterns of change on imagery were related to contemporary plot-scale (20 X 20 m) field measurements of vegetation structure and soil to identify settings that conferred vegetation stability or susceptibility to a type conversion. On the sandy mesquite site, stable grass and grass-mesquite patches were structured by local soil characteristics at the plant-patch scale (e.g. petrocalcic horizons and surface texture) and landscape position at the basin scale. Conversion to shrub-dominated coppice dunes and loss of grass was a function of the density and arrangement of mesquite plants at the plant-patch scale. At the juniper site, persistence of a savanna structure and the conversion to juniper woodland was controlled by thresholds related to juniper density and arrangement that were dictated by landscape scale variation in soils, geomorphology, elevation, and topographic setting. This example illustrates contrasting sites where the processes differ but the outcomes do not (i.e., spatial variation in temporal changes in grass-woody ratios). The relative importances of each element of the conceptual framework provide ecological insight to grassland-to-shrubland transitions as a whole as well as these specific cases which may inform future management.}, keywords = {grass-to-shrubland, spatial}, author = {D. Goolsby and Brandon T Bestelmeyer and Steven R. Archer} } @article {50100, title = {A simplified data assimilation method for reconstructing time-series MODIS NDVI data}, journal = {Advances in Space Research}, volume = {44}, year = {2009}, pages = {501-509}, abstract = {

The Normalized Difference Vegetation Index (NDVI) is an important vegetation index, widely applied in research on global environmental and climatic change. However, noise induced by cloud contamination and atmospheric variability impedes the analysis and application of NDVI data. In this work, a simplified data assimilation method is proposed to reconstruct high-quality time-series MODIS NDVI data. We extracted 16-Day L3 Global 1\ km SIN Grid NDVI data sets for western China from MODIS vegetation index (VI) products (MOD13A2) for the period 2003{\textendash}2006. NDVI data in the first three years (2003{\textendash}2005) were used to generate the background field of NDVI based on a simple three-point smoothing technique, which captures annual features of vegetation change. NDVI data for 2006 were used to test our method. For every time step, the quality assurance (QA) flags of the MODIS VI products were adopted to empirically determine the weight between the background field and NDVI observations. Ultimately, more reliable NDVI data can be produced. The results indicate that the newly developed method is robust and effective in reconstructing high-quality MODIS NDVI time-series.

}, keywords = {MODIS, NDVI, remote sensing, time-series}, doi = {10.1016/j.asr.2009.05.009}, author = {Gu, J. and Xia Li and C. Huang and Gregory S. Okin} } @article {50117, title = {Sediment deposition and soil nutrient heterogeneity in two desert grassland ecosystems, southern New Mexico}, journal = {Plant and Soil}, volume = {319}, year = {2009}, pages = {67-84}, abstract = {

The role of wind in changing the spatial heterogeneity of soil resources in erosion-dominated semiarid ecosystems is well known. Yet the effect of windblown sediment deposition on soil nutrient distribution and ecosystem dynamics at local and landscape scales has received little attention. We examined the effects of enhanced sediment deposition on the spatial distribution of soil nutrients at the Jornada Experimental Range, southern New Mexico. Enhanced sediment deposition was obtained as a result of grass cover reduction in the upwind portion of the experiment in two sites co-dominated by mesquite and one of two grass species with different morphologies. The spatial characteristics of soil available nitrogen (including ammonium, nitrite, and nitrate), phosphate, potassium, and calcium were quantified using a variety of traditional and geostatistical analyses. Our results showed that enhanced deposition led to considerable reduction in both mean soil nutrient concentrations and coefficients of variation over a two-year period (2004{\textendash}2006). Given the observed increase in the scale of spatial dependence for available nitrogen, but not for potassium, phosphate, and calcium following enhanced sediment deposition, we suggest that soil available nitrogen may be particularly responsive to increased aeolian activities due to livestock grazing and other anthropogenic activities that remove vegetation. Our study further suggests that soil particles deposited in the downwind area may be {\textquotedblleft}nutrient-imbalanced.{\textquotedblright} Specifically, the lower-than-normal available nitrogen concentrations in the wind-deposited soils may inhibit the growth of grasses and the germination of seeds. For wind-erodible ecosystems found in southern New Mexico, structures of Bouteloua-dominated communities may be particularly susceptible to change under enhanced soil erosion conditions.

}, keywords = {aeolian processes, available nitrogen, ecosystem dynamics, geostatistics, sediment deposition, spatial heterogeneity}, doi = {10.1007/s11104-008-9850-7}, url = {files/bibliography/JRN00528.pdf}, author = {Junran Li and Gregory S. Okin and Lorelei Alvarez and Howard Epstein} } @article {50123, title = {Scale and the isotopic reocrd of C4 plants in pedogenic carbonate: from the biome to the rhizosphere}, journal = {Ecology}, volume = {90}, number = {6}, year = {2009}, note = {//USDA,OTHER//LTER V//entered 07/13/2009; pdf available}, month = {2009}, pages = {1498-1511}, abstract = {The 13C/12C ratio in pedogenic carbonate (i.e., CaCO3 formed in soil) is a significant tool for investigating C4 biomes of the past. However, the paleoecological meaningof d13C values in pedogenic carbonate can change with the scale at which one considers the data. We describe studies of modern soils, fossil soils, and vegetation change in the Chihuahuan Desert of North America and elsewhere that reveal four scales important for paleoecologic interpretations. (1) At the broadest scale, the biome scale (hundreds to millions of km2), an isotopic record interpreted as C3 vegetation replacing C4 grasslands may indicate invading C3 woody shrubs instead of expanding C3 forests (a common interpretation). (2) At the landscape scale (several tens of m2 to hundreds of km2), the accuracy of scaling up paleoclimatic interpretations to a regional level is affected by the landform containing the isotopic record. (3) At the soil-profile scale (cm2 to m2), soil profiles with multiple generations of carbonate mixed together have a lower-resolution paleoecologic record than soil profiles repeatedly buried. (4) At the rhizosphere scale (lm2 to cm2), carbonate formed on roots lack the 14{\textendash}17{\o} enrichment observed at broader scales, revealing different fractionation processes at different scales. A multi-scale approach in dealing with d13C in pedogenic carbonate will increase the accuracy of paleoecologic interpretations and understanding of soil{\textendash}geomorphic{\textendash}climatic interactions that affect boundaries between C4 and C3 vegetation.}, keywords = {article, C3 vs C4 vegetation, carbon isotopes, Chihuahuan Desert, climate change, desertification, Jornada Experimental Range, journal, landscape ecology, pedogenic carbonate, peleoclimate, peleoecology, soil-geomorphic-clmatic interaction, southern New Mexico, USA}, author = {Curtis H. Monger and David R. Cole and B. J. Buck and R. A. Gallegos} } @article {50125, title = {The significance of termites as decomposers in contrasting grassland communities of semi-arid eastern Australia}, journal = {Journal of Arid Environments}, number = {73}, year = {2009}, month = {01/2009}, pages = {113-119}, chapter = {113}, abstract = {

Decomposition of various litter forms including dead tussocks of two native perennial grasses, woollybutt (Eragrostis eriopoda) and mulga mitchell (Thyridolepis mitchelliana), as well as roots of woollybutt, dung of sheep and kangaroo, and bleached toilet rolls, was studied in contrasting grazing exclosures, half of which had termites excluded by biocide (termiticide) treatment. Dead mulga mitchell tussocks decayed more rapidly than woollybutt tussocks during the first 17 months post mortem. Thereafter, rate of decay differed little between species. After 3 years, only small amounts of tussock residues of either species remained and only then did the impact of biocide treatment become significant. Decomposition of kangaroo pellets was typically bimodal with significantly higher decomposition recorded in the controls (no biocide) up to 40 months after treatment, and many intact pellets remaining in the biocide-treated plots. While decomposition of sheep pellets showed similar bimodality, decomposition remained significantly lower in the biocide treatments for the entire duration of the experiment. Results suggest that abiotic processes, including those induced by UV radiation, may be dominant influences mediating decomposition of litter in these semi-arid ecosystems, especially following high rainfall seasons when abundant grass biomass has been generated providing a surfeit of potential forage for harvester termites.

}, keywords = {biocide, dead tussocks, litter decomposition, sheetp and kangaroo dung}, doi = {10.1016/j.jaridenv.2008.08.004}, url = {/files/bibliography/09-003.pdf}, author = {J. Noble and W. Mueller and Walter G. Whitford and Pfitzner, G.H.} } @conference {50133, title = {Shifts in species dominance at a biome transition zone: Importance of asymmetric competition to long-term trends}, booktitle = {2009 LTER All Scientist Meeting}, year = {2009}, abstract = {Landscapes at the Sevilleta LTER site are dominated or codominated by two perennial grasses from different biomes, Bouteloua eriopoda (black grama) from the Chihuahuan Desert and B. gracilis (blue grama) from the shortgrass steppe, and the Chihuahuan Desert shrub Larrea tridentata (creosotebush). We used a long-term removal study to examine inter-specific interactions between these dominant species, and to determine which species would eventually dominate following the removal of the others. Plants of the dominant species were removed from 5 3m x 4m plots in 1995 at five sites that were either dominated by one of the three species (blue grama grasslands, black grama grasslands, cresootebush shrublands) or at ecotones codominated by two species (blue grama/black grama; black grama/creosotebush). Plant cover is estimated annually, and removals have been conducted annually since that time. Results show that removal of black grama has little effect on cover of blue grama whereas removal of blue grama or creosotebush results in marked increases in cover of black grama. Our results show that competition between black grama and either blue grama or creosotebush is asymmetric. These interactions suggest that black grama dominance may be reduced in the future under climate conditions that favor growth of either blue grama or creosotebush since these species can outcompete black grama. Landscape patterns associated with soil texture can also be explained by these interspecific interactions for soil water in this semiarid environment.}, keywords = {asymmetric, B. gracilis, black grama, Bouteloua eriopoda, creosotebush, LTER, Sevilleta}, author = {Debra C. Peters and Jin Yao} } @article {50140, title = {Small mammal herbivory: Feedbacks that help maintain desertified ecosystems}, journal = {Journal of Arid Environments}, volume = {73}, number = {73}, year = {2009}, month = {01/2009}, pages = {62-65}, chapter = {62}, abstract = {

We tested the hypothesis that herbivores contribute to feedbacks maintaining arid ecosystems in a degraded state. We studied small mammal herbivory on a subshrub, broom snakeweed (Gutierrezia sarothrae), and perennial grasses at three sites: (1) ungrazed black grama (Bouteloua eriopoda) grassland; (2) grassland degraded by intense short-duration grazing; and (3) mesquite (Prosopis glandulosa) coppice dunes. Snakeweed was browsed by herbivores primarily during dry winter months. The average percent of G. sarothrae standing crop biomass removed by browsing was 9.2 in ungrazed grassland, 7.4 in intensely grazed grassland, and 4.1 in the dunes. In ungrazed grassland, an average of 12\% of grass cover was harvested by herbivores; in the intensely grazed plots \– 80\%. Herbivore exclusion plots showed that jackrabbits (Lepus californicus) were the primary browsers on snakeweed and rodents on grasses and G. sarothrae inflorescences. Rodent removal of G. sarothrae inflorescences allows wind dispersal of seeds in disturbed and desertified areas, thereby increasing abundance of this poisonous shrub. Grass-tiller cutting by rodents provides a strong feedback that may be responsible for keeping the grass cover low on the intensely grazed areas. Jackrabbit pruning has little effect on G. sarothrae abundance at any stage of desertification.

}, keywords = {browsing, desertification, herbivory, jackrabbit, livestock grazing, snakeweed}, doi = {10.1016/j.jaridenv.2008.09.003}, url = {/files/bibliography/09-001.pdf}, author = {Roth, G.A. and Walter G. Whitford and Yosef Steinberger} } @article {50150, title = {Seasonal changes in one seed juniper intake by sheep and goats in relation to dietary protein and plant secondary metabolites}, journal = {Small Ruminant Research}, volume = {81}, year = {2009}, month = {2009/02/19}, pages = {152-162}, abstract = {Seasonal variation in plant secondary metabolites (PSM) can influence voluntary intake levels of one-seed juniper (Juniperus monosperma Englem. Sarg.) of sheep and goats. Supplemental nutrients could mitigate the deterrent effects of juniper PSM. We determined the concentration of mono-and sesqui- terpenes, total phenolics and condensed tannins in one-seed juniper leaves in summer, fall, winter, and spring, and tested their effects on juniper intake of 12 Western White Face ewes (74.9 {\textpm} 1.23 kg) and 12 Boer-Spanish does (46.7 {\textpm} 1.25 kg) fed isoenergetic diets (1.6\% BW) with no supplemental protein (Control, 5\% CP) or with addition of a rumen degradable (RDP, 12.5\% CP) or undegradable (RUP, 12.5\% CP) protein supplement. Animals were fed unrestricted amounts of freshly harvested juniper branches for 30 min and short-term juniper intake was determined for 10 d per season. Total terpenes, total phenolics, and condensed tannins varied across seasons (P<0.05), and were positively correlated to each other (P<0.05). Juniper intake was greater for goats than sheep (P<0.05), and twice as high for supplemented vs. control animals (P<0.05). Juniper intake in the fall, when levels of plant secondary metabolites were highest, was 41, 58, and 52\% less than in summer, winter, and spring (P<0.05), respectively. Supplements with RDP and RUP promoted different patterns of juniper intake among seasons (P<0.05), herbivores (P<0.05), and individual animals (P<0.05). This study suggests that supplemental protein can increase voluntary intake of one-seed juniper of small ruminants during seasons when plant secondary metabolite levels are low. Proteins of different degradability appear to affect seasonal patterns of juniper intake differently.}, keywords = {goats, journal, juniper, protein supplements, ruminant, secondary metabolites, sheep}, url = {/files/bibliography/09-006.pdf}, author = {S. A. Utsumi and Andr{\'e}s F. Cibils and Richard E. Estell and S. Soto-Navarro and D. VanLeeuwen} } @conference {50151, title = {Setting the stage to enhance ecological site description appplications to wildlife management in sagebrush ecosystems: A 2007 society for range management workshop}, booktitle = {Society for Range Management Annual Meeting}, series = {62nd Society for Range Management Annual Meeting}, year = {2009}, month = {02/2009}, pages = {1000-16}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Alb., NM}, abstract = {

Widespread loss, alteration and degradation of sagebrush ecosystems have created complex challenges for managers seeking to conserve dependent wildlife species. A half century of range and wildlife research has generated an extensive and diverse base of information to assist managers in making land management decisions. However, this information may not be readily available to managers. Thus, there exists a need to develop an interdisciplinary, transparent tool that organizes and communicates this information to decision makers. Ecological Site Descriptions (ESDs) constitute a viable management tool that potentially could improve range and wildlife managers\’ capabilities to describe and manage sagebrush ecosystems. To set the stage for this transition, the Society for Range Management in concert with federal, state, and private partners sponsored a workshop in Park City, Utah in 2007. The objectives of workshop were to: 1) introduce habitat managers, planners and policy makers to the use and development of ESDs, 2) encourage interdisciplinary improvement of wildlife interpretations in ESDs and enhance the utility of this tool for managing sagebrush ecosystems, and 3) identify information gaps and define priorities for research and development. This workshop was attended by over 300 land and wildlife/habitat managers, biologists, range ecologists and soil scientists, technical assistance professionals, local sage grouse working group members, consultants, and petroleum industry representatives from throughout western North America. In this poster we describe the process used by SRM and its partners to plan, conduct, and evaluate this successful workshop.

}, keywords = {abstract, Ecological Site Description, ecosystem, ESD, land management, sagebrush, SRM}, author = {Wendell, G. and Joel R. Brown} } @conference {50165, title = {Social-biophysical feedbacks and land change in an arid rangeland region}, booktitle = {93rd Ecological Society of America Annual Meetings}, year = {2008}, month = {August 3, 2008}, pages = {PS 51-157}, address = {Milwaukee, WI}, abstract = {Studies of human-dominated ecosystems have traditionally externalized human agents and their behavior. Rangelands of the southwestern U.S. are no exception: in spite of century-long studies of vegetation change, the specific role of human decisions and their feedbacks with land condition are unknown. It is likely that prevention of future land degradation as well as opportunities for restoration will depend largely on our ability to manipulate these feedbacks. To support this perspective, we undertook a region-scale study of the relationships between the geophysical setting, land condition, and the history and current attributes of Bureau of Land Management (BLM) grazing allotments in south-central New Mexico. National Cooperative Soil Survey soil maps coupled to Ecological Site Descriptions were used to characterize the geophysical setting and inherent resilience, expert-supported, remote-sensed maps of vegetation states were used to characterize land condition, and BLM allotment records were used to characterize human dimensions variables including frequency of allotment turnover, the sense of impermanence, agency conflict, ranch type (trophy or dependent family) and management type (cautious vs. incautious). BLM allotment polygons were then attributed with human dimensions and geophysical/land condition data for analysis.}, keywords = {human, human-domiated, vegetationchange}, author = {Brandon T Bestelmeyer and R. K. Skaggs} } @article {50171, title = {State-and-transition models: recommendations for resilience-based application}, journal = {Rangeland Ecology and Management}, volume = {61}, year = {2008}, month = {July 2008}, pages = {359-367}, abstract = {The objective of this paper is to recommend conceptual modifications for incorporation into the state-and-transition model (STM) framework to: 1) explicitly link this framework to the concept of ecological resilience, 2) direct management attention away from thresholds and toward the maintenance of state resilience, and 3) enhance the ability of STMs to capture a broader set of relevant ecological information to support ecosystem management. Ecological resilience describes the amount of change or disruption that is required to transform a system from being maintained by one set of mutually reinforcing processes and structures to a different set of processes and structures (e.g., alternative stable state). Effective ecosystem management must focus on the adoption of management practices and policies that maintain or enhance ecological resilience to prevent stable states from exceeding potential thresholds. In this context, resilience management does not focus on thresholds per se, but rather on within-state dynamics that influence resilience and state proximity and vulnerability to thresholds. Resilience-based ecosystem management provides greater opportunities to incorporate adaptive management than does threshold-based management because thresholds specifically define the limits of state resilience, rather than the conditions that determine the likelihood that these limits will be surpassed. We recommend that the STM framework incorporate triggers, at-risk communities, feedback mechanisms, and restoration pathways and develop process-specific indicators that enable managers to identify at-risk plant communities and potential restoration pathways. Three STMs representing unique ecological conditions and geographic locations are presented to illustrate the incorporation and application of these recommendations. We anticipate that these conceptual modifications will enhance the ability of the STM framework to more efficiently capture and convey ecological information supporting ecosystem management to a broader range of stake holders and special interest groups.}, keywords = {resilience-based, state-and-transition}, url = {/files/bibliography/08-025.pdf}, author = {D.D. Briske and Brandon T Bestelmeyer and T.K. Stringham and P. L. Shaver} } @article {50184, title = {Structural heterogeneity and productivity of a tall fescue pasture grazed rotationally by cattle at four stocking densities}, journal = {Grassland Science}, volume = {54}, year = {2008}, note = {//OTHER//OTHER//entered 06/02/2008 per DEP}, month = {2008}, pages = {9-16}, abstract = {

The spatial heterogeneity in the structure and the productivity of the vegetation was examined in a tall fescue (Festuca arundinacea Schreb.) pasture rotationally grazed at four stocking densities in the Pampean region of Argentina. The examined pasture was grazed at the stocking densities of 3.6, 4.6, 5.6 and 6.6\ animals\ ha-1 with a two-paddock 14-day rotational grazing system. Spatial distribution of plant height was examined as well as the percentages of short patch area (heavily utilized patches) or tall patch area (areas ungrazed or lightly defoliated). In addition, biomass, growth rate and relative growth rate were assessed for both short and tall patches. Grazing generated patchiness in vegetation structure and growth at all stocking densities. Increased stocking density caused an increase in the percentage of the short patch area in the paddocks. Short patches had relatively less live biomass than tall ones, but their relative growth rate was 31\% higher than that of tall patches (0.021\ {\textpm}\ 0.007 vs 0.016\ {\textpm}\ 0.005\ g\ DM\ g\ DM-1\ day-1). The increase in stocking density enlarged the proportion of short patch areas with higher relative growth rate. The relative growth rate (average between short and tall patches) of the two highest stocking densities was 61.7\% higher than that of the low stocking density treatments (0.023\ {\textpm}\ 0.006 vs 0.014\ {\textpm}\ 0.004\ g\ DM\ g DM-1\ day-1). Although the growth rate of the short patches did not exceed the value of the tall patches, the high value of relative growth rate appeared to indicate a higher photosynthetic capacity of the short patches. Moreover, live biomass did not decrease during the experimental period even in the short patch areas showing that, in the particular conditions of our study, overgrazing did not occur at the range of the stocking density examined.

}, keywords = {article, cattle grazing management, cattle grazing, effects on plants, cattle grazing, forage utilization, cattle grazing, productivity, cattle grazing, structural heterogeneity, cattle grazing, vegetation change, grazing management, cattle, journal}, doi = {10.1111/j.1744-697X.2008.00099.x}, url = {files/bibliography/08-059.pdf}, author = {Cid, M.S. and Ferri, C. M. and M. A. Brizuela and O. E. Sala} } @article {50187, title = {The spread of invasive species and infectious disease as drivers of ecosystem change}, journal = {Frontiers in Ecology and the Environment}, volume = {6}, number = {5}, year = {2008}, note = {//NONE//NONE//entered 07/28/2008}, month = {2008}, pages = {238-246}, abstract = {Invasive species, disease vectors, and pathogens affect biodiversity, ecosystem function and services, and human health. Climate change, land use, and transport vectors interact in complex ways to determine the spread of native and non-native invastive species, pathogens, and their effects on ecosystem dynamics. Early detection and in-depth understanding of invasive species and infectious diseases will require an integrated network of research platforms and information exchange to identify hotspots of invasion or disease emergence. Partnerships with state and federal agencies that monitor the spread and impacts of invasive species and pathogens iwll be critical in developing a national data and research network that can facilitate a full understanding of the resulting effects on ecosystems and society. Citizen science can also play a role; individuals can report new invasions, record phenological changes associated with invasions or disease outbreaks, and can participate in efforts such as the Breeding Bird Survey, which may reveal long-term biotic change following species invasions and disease spread. The ecological and societal impacts of invasive species and pathogens differ across gradients of climate and land use, and in the presence of global climate change may exacerbate both their propagation and impacts. Understanding the interactions of invasive species, disease vectors, and pathogens with other drivers of ecosystem change is critical to human health and economic well-being.}, keywords = {article, climate change, continental scales, climate change, drivers, climate change, ecological responses, climate change, ecosystem responses, climate change, site network, ecosystem change, drivers, ecosystem change, infectious disease, ecosystem change, invasive species, ecosystem, climate change, infectious disease, invasive species, journal}, isbn = {doi:10.1890/070151}, author = {Crowl, Todd A. and Crist, Thomas O. and R. R. Parmenter and Belovsky, Gary and Ariel E. Lugo} } @mastersthesis {50189, title = {Sediment transport \& vegetation change: A Study Using Medium-Scale Landscape Units as Indicators of the Influence of a Vegetation Transition on Sediment Production - Jornada Experimental Range, New Mexico}, year = {2008}, note = {//USDA//LTER V//entered 2/19/2009ProCite field[12]: In File (02/19/2009)}, month = {2008}, pages = {186 pp}, school = {University of Leicester}, type = {PDF}, abstract = {

Set against a background of vegetation change from grassland to shrubland, this project used the small agricultural stock ponds of the Jornada Experimental Range, in the semi-arid Chihuahuan Desert of New Mexico, to quantify sediment production from the expanding shrubland vegetation communities. In quantifying sediment production, conclusions can be drawn about the importance of land cover in rangeland management, but more significantly for this study, a valuable dataset is generated at a generally under-researched scale. Small pond studies are necessary to expand the existing knowledge on up-scaling of erosion datasets. Sediment yield data are primarily collected from erosion plots, or at a much larger scale using erosion models. These models rely on data from plots for calibration and validation. However, data collected at the plot scale do not accurately represent sediment production at larger scales, often resulting in the propagation of errors. New methods of considering sediment routing through a catchment are necessary if understanding at an intermediate (catchment) scale is to be gained. Three approaches were used to generate comparable datasets: repeated surveys, sediment dating, and reconstructing runoff coefficients from aerial photographs. The results from these projects show internally consistent results, as well as agreement with similar studies in the wider erosion-study literature. This demonstrates the potential of this technique to produce viable datasets. The principal findings of this research are that runoff coefficients calculated at the catchment scale do not show the expected reduction from those gained from plots. This is primarily thought to be a methodological problem. However, the principal aim of the research was met with two complimentary datasets showing variations in sediment fluxes from shrubland vegetation. The dataset was insufficient to conclude this was statistically different from the historic grasslands, but this does appear to be the case. The idea of travel distance of particles as a control on sediment production was only partially substantiated by this work: fining of sediment is evident only within the catchments of the ponds. No statistical difference was found between the particle-size distribution of pond and catchment samples.

}, keywords = {dirt tanks, dissertation, hydrology, sediment transport, hydrology, vegetation change, pond studies, stock tanks, thesis, vegetation change, hydrology, vegetation change, sediment transport}, url = {files/bibliography/JRN00512.pdf}, author = {Cunningham, Lisa Michelle} } @article {50190, title = {Sustainable rangeland management, economic growth, and a cautious role for the SRM}, journal = {Rangelands}, volume = {30}, year = {2008}, month = {December 1, 2008}, pages = {33-37}, abstract = {Interest in the art and science of rangeland management increased dramatically during the 20th century and it was out of this interest that the profession of rangeland management was born. As public interest in rangeland management grew, so did the number, breadth, and depth of rangeland management issues. Consequently, the profession has responded to these new challenges and opportunities by encompassing a wider array of rangeland management issues, such as biological diversity, noxious and invasive weeds, protection of rangeland and open space values, and endangered species. The evolution of resource management policy and practice reveals a general concern with ecosystem health and sustainability, which in turn reflects an overall concern in academia and public life about ecological and economic sustainability. The optimum size and growth rate of an economy may only be ascertained in the context of a staggering array of ecological and cultural factors. One of these factors is the relationship between economic growth and the environment, in our case, rangeland ecosystems. A critical role for the profession of rangeland management is to describe the basic trade-off between economic growth and sustainable rangeland management and to communicate clearly with people interested in that relationship.}, keywords = {economic growth, rangeland management, SRM, sustainable}, url = {/files/bibliography/08-041.pdf}, author = {Czech, B. and Heitschmidt, R. and Joel R. Brown and Hild, A.} } @inbook {50193, title = {Snowfall, snowpack and meltwater chemistry}, booktitle = {Principles of Snow Hydrology}, year = {2008}, month = {July 2008}, pages = {211-234}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, chapter = {Chapter 8}, address = {Cambridge, NY}, abstract = {

Biogeochemical cycling of nutrients and pollutants in the environment is significantly affected by the occurrence of snowfall and snowpacks. Snowpacks can be viewed as reservoirs of chemicals that, unlike substances dissolved in rainfall, can be largely stored for significant periods of time during winter until melting occurs. Snowpacks reflect the chemical nature of the original snowfall events or wet deposition that accumulated to create them as well as the dry deposition of chemicals occurring as aerosol droplets, particles and gases in the atmosphere falling onto the snowpack surface during non-precipitation periods. Both naturally cycling chemicals and pollutants in the environment end up in the snowpack in this manner. Snowpack chemistry may also be affected by interactions with plant canopies during interception and the activity of organisms that find a home in the snow. Once melting or rain-on-snow events occur, chemicals are redistributed and released from the snowpack non-uniformly due to fractionation processes leading to relative enrichment of the initial liquid water releases. In polluted environments, early spring fish kills have been attributed to effects of these initial concentrated acidic snowmelt runoff events that caused toxic levels of dissolved aluminum to occur in streams. Studies have also shown that some ions are preferentially eluted or leached from the snowpack in different ratios than found in the snow itself. Thus, the overall effect of snow on chemicals cycling in the environment is to first store and then alter the timing and concentrations of ions moving in water through a catchment.

}, keywords = {chemistry, snow, snowfall, snowpacks}, url = {http://www.cambridge.org/us/academic/subjects/earth-and-environmental-science/hydrology-hydrogeology-and-water-resources/principles-snow-hydrology}, author = {D. DeWalle and A. Rango} } @inbook {50195, title = {Snowmelt Runoff}, booktitle = {Principles of Snow Hydrology}, year = {2008}, month = {July 2008}, pages = {235-265}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, chapter = {Chapter 9}, address = {Cambridge, NY}, abstract = {

Understanding the generation of streamflow from snowmelt involves integration of processes that produce meltwater within the snowpack, processes that delay and store liquid water in the snowpack and processes that direct the flow of meltwater through watersheds to stream channels. Computations of liquid water dynamics in snowpacks and melt rates have been covered in prior chapters. In this chapter these concepts and computations are synthesized with a discussion of the movement of meltwater within watersheds and the resulting hydrographs of snowmelt runoff. Emphasis is given to factors unique to generation of streamflow from snowmelt, such as frozen ground effects and rain-on-snow flooding.

}, keywords = {meltwater, snow hydrology, snowmelt runoff, snowpack}, url = {http://www.cambridge.org/us/academic/subjects/earth-and-environmental-science/hydrology-hydrogeology-and-water-resources/principles-snow-hydrology}, author = {D. DeWalle and A. Rango} } @inbook {50199, title = {Snowpack Condition}, booktitle = {Principles of Snow Hydrology}, year = {2008}, month = {July 2008}, pages = {48-75}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, chapter = {Chapter 3}, address = {Cambridge, NY}, abstract = {

Once snow has accumulated on the landscape, the individual snowflakes and ice grains can be rapidly transformed or metamorphosed into a structured snowpack. Metamorphism ultimately influences the thermal conductivity and liquid permeability of the snowpack that in turn influence the snowpack temperature regime and storage and release of liquid water. Snowpacks vary seasonally from low density, sub-freezing snowpacks capable of refreezing any liquid water inputs to isothermal, dense snowpacks that rapidly transmit liquid water to the ground below. In this chapter, important processes controlling snowpack metamorphism and the conduction of heat and liquid water in snow are described along with methods hydrologists use to describe snowpack condition.

}, keywords = {conduction of heat and liquid water, metamorphism, processes, snowpack}, url = {http://www.cambridge.org/us/academic/subjects/earth-and-environmental-science/hydrology-hydrogeology-and-water-resources/principles-snow-hydrology}, author = {D. DeWalle and A. Rango} } @inbook {50198, title = {Snowpack Energy Exchange: Basic Theory}, booktitle = {Principle of Snow Hydrology}, year = {2008}, month = {July 2008}, pages = {146-181}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, chapter = {Chapter 3}, address = {Cambridge, NY}, abstract = {

The exchange of energy between the snowpack and its environment ultimately determines the rate of snowpack water losses due to melting and evaporation/sublimation. Energy exchange primarily occurs at the snowpack surface through exchange of shortwave and longwave radiation and turbulent or convective transfer of latent heat due to vapor exchange and sensible heat due to differences in temperature between the air and snow. Relatively small amounts of energy can also be added due to warm rainfall on the snowpack surface and soil heat conduction to the snowpack base. Changes in snowpack temperature and meltwater content also constitute a form of internal energy exchange. Melting usually represents the major pathway for dissipation of excess energy when the snowpack ripens and becomes isothermal at 0\&$\#$39;C (see Chapter 3).

}, keywords = {energy, snowpack, theory}, url = {http://www.cambridge.org/us/academic/subjects/earth-and-environmental-science/hydrology-hydrogeology-and-water-resources/principles-snow-hydrology}, author = {D. DeWalle and A. Rango} } @inbook {50200, title = {Snowpack energy exchange: Topographic and forest effects}, booktitle = {Principles of Snow Hydrology}, year = {2008}, month = {July 2008}, pages = {182-210}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, chapter = {Chapter 7}, address = {Cambridge, NY}, abstract = {

Recent innovations in computing techniques and the need for modeling snowpack energy exchange processes for large diverse basins have lead to consideration of topographic and forest effects. Both topography and forests can have a major impact on snowpack radiation energy exchange. Effects on convective exchange are less well known. Methods for adjusting the basic theory of snowpack energy exchange for the effects of topography and forests are considered in this chapter. Latent heat and sensible heat convection were much lower in the forest than in the open due to reduced wind speeds. Net radiation was the dominant snowpack energy budget component at both the open and forest sites. Net radiation was reduced by about 20\% by the forest relative to the open, based upon regression analysis of hourly data. Because of overall differences in net radiation and total energy supply to the snowpack, daily snowmelt rates in the forest were reduced by 15-60\% compared to melt at the open site. Results of this study illustrate how forest cover can reduce the snowpack energy supply and how more humid conditions can increase the importance of latent heat convection as a source of melt energy.

}, keywords = {effects, energy, exchange, forest, modeling, snowpack, topographic}, url = {http://www.cambridge.org/us/academic/subjects/earth-and-environmental-science/hydrology-hydrogeology-and-water-resources/principles-snow-hydrology}, author = {D. DeWalle and A. Rango} } @conference {50211, title = {Shrub expansion in northern Chihuahuan Desert grasslands: Spatial patterns and biophysical constraints}, booktitle = {93rd Ecological Society of America Annual Meeting}, year = {2008}, month = {August 4-8, 2008}, pages = {PS 37-25}, address = {Milwaukee, WI}, abstract = {Conserving and restoring grasslands and shrub-steppe has important ecological and socioeconomic implications in arid rangelands of the world. Among the greatest contemporary threats to the structure, function and biological diversity of desert grassland and shrub savanna ecosystems of the southwestern United States is the displacement of mesophytic grasses by xerophytic woody plants. The needs of land managers in addressing this issue have surpassed the information provided by inventories and traditional monitoring programs. Land managers must understand the mechanisms behind shrub expansion in order to identify grasslands that are at risk and shrublands that may be viable candidates for grassland restoration. As yet, there are no objective criteria for making these key distinctions. Through a combination of field sampling and spatial modeling we sought to create a predictive understanding of the biophysical conditions under which grasslands are converted to shrublands. We asked: What are the physiographic settings of persistent grass patches and what environmental factors contribute to their persistence? In communities that are a mosaic of grass and shrub patches, which of these are stable and which are in the process of transitioning to shrub dominance? What do spatial patterns of past shrub expansion suggest about future landscape change? As a first step in addressing these questions, we characterized landscape-scale perennial plant cover across grassland-to-shrubland gradients within the Jornada Basin near Las Cruces, NM. Soil was characterized to 150 cm or to restrictive calcium carbonate horizon and the relationships between perennial plant assemblages and soil characteristics were explored using multivariate statistics. Changes in shrub and perennial grass patch structure and distribution were quantified using time-series aerial photography (1940s - 2000s). Field survey and aerial photography data were then used to develop a model of patch structure dynamics focused on characterizing patterns of vegetation structure and cover that portend dramatic shifts in shrub-grass abundance.}, keywords = {grassland, shrub-steppe, socioeconomic}, author = {D. Goolsby and Brandon T Bestelmeyer} } @proceedings {50217, title = {Strategies for sustaining multiple ecosystem services from rangelands}, volume = {II}, year = {2008}, month = {June 30 - July 5}, pages = {1094}, address = {Hohhot, China}, abstract = {The application of natural resource science to both management needs and policy formation has been spotty, at best. Interestingly, rangeland science had an early history of closely supporting management needs and USA rangeland policies during the early 20th century. This history of support unraveled during the mid part of the 20th century as the science failed to address increasingly relevant socioeconomic factors, and rangelands were sought to provide other services beyond food and fiber. Recently, rangeland science has again been coupled to management and policy. Sustaining any combination of goods and services from rangelands requires that linkages among science, management and policy be well established and functional. An analysis of this history of the coupling, uncoupling and then recoupling of rangeland science with both management and USA rangeland policies may provide useful insights for sustained use of these resources.}, keywords = {ecosystem, management, multiple, policy, proceedings, rangelands, strategies, sustaining}, url = {/files/bibliography/08-032.pdf}, author = {Kris Havstad and Joel R. Brown and Jeffrey E. Herrick and Debra C. Peters and E.L. Fredrickson and Brandon T Bestelmeyer and Pieper, Rex D.} } @article {50227, title = {Simplifying ecological site verification, rangeland health assessments, and monitoring}, journal = {Rangelands}, volume = {30}, number = {6}, year = {2008}, note = {Trade Journal}, pages = {24-26}, abstract = {

During the past several decades, scientists and land managers in North America have increasingly recognized the importance of rangeland assessment relative to ecological potential based on soil and climate. The adoption of the site potential based {\textquotedblleft}ecological site{\textquotedblright} system was recently formalized in a memorandum of understanding between the US Forest Service, the Bureau of Land Management, and the Natural Resources Conservation Service. During the same period, integration of soil and vegetation indicators has led to the development and adoption of new assessment protocols, such as {\textquotedblleft}Interpreting Indicators of Rangeland Health. {\textquotedblleft}In addition to requiring ecological site identification based on soils, this protocol includes at least two indicators that require soil excavation: {\textquotedblleft}soil surface loss or degradation{\textquotedblright} and {\textquotedblleft}compaction layer.{\textquotedblright} The {\textquotedblleft}pedestals and/or terracettes{\textquotedblright} indicator also sometimes requires excavation to determine whether erosion or deposition has resulted in the apparent elevation of plants relative to the soil surface. All three of these indicators can be difficult to assess in some ecological sites, and we have found that the best way to learn is through observation and comparison of a large number of soil profiles. Many monitoring protocols in the United States and Canada also include soil indicators. Some have even argued that, {\textquotedblleft}If one agrees that a variety of current and potential plant communities can occur above a conservation threshold for a particular ecological site, then monitoring vegetation has to take a backseat to monitoring soils.{\textquotedblright}

}, doi = {10.2111/1551-501X-30.6.24}, url = {/files/bibliography/08-052.pdf}, author = {Jeffrey E. Herrick and Brandon T Bestelmeyer and K. Crossland} } @conference {50223, title = {Soil, resilience, and state and transition models}, booktitle = {Society for Range Management Annual Meetings}, series = {Building Bridges: Grasslands to Rangelands}, year = {2008}, month = {January 26-31, 2}, pages = {1514}, address = {Louisville, KY}, abstract = {State and transition models are based on the assumption that less resilient systems are more susceptible to state changes. The objective of this paper is to show how two different types of soil properties contribute to resilience through their direct and indirect effects on ecosystem processes, and through feedbacks with plants, and how this information can be used to guide the sampling of dynamic soil properties. Relatively static soil and topographic properties including texture, mineralogy, depth, slope and aspect determine, together with climate, the ecological site potential. This potential is realized through the establishment of plant and soil biotic communities, and through the subsequent modification of dynamic properties throughout the soil profile including infiltration and water holding capacity and nutrient availability. We will present results of new analyses of variability in soil properties at multiple spatial scales that illustrate both the interactions between relatively static and dynamic soil properties, and the appropriate scales for sampling. We will conclude with the results of a modeling exercise showing how changes in a relatively static soil property (soil surface texture) generated by a state change in an upwind ecological site can trigger soil-plant feedbacks resulting in changes in both dynamic soil properties and plant community composition, and discuss the application of an understanding of changes in relatively static and dynamic soil properties to assessment and monitoring of the effects of conservation practices (including CEAP).}, keywords = {abstract, resilience, state and transition models}, author = {Jeffrey E. Herrick and S.A. Wills and Debra C. Peters and A.J. Tugel and Brandon T Bestelmeyer} } @article {50230, title = {Shrub encroachment in North American grasslands: Shifts in growth form dominance rapidly alters control of ecosystem carbon inputs}, journal = {Global Change Biology}, volume = {14}, year = {2008}, month = {January 30, 2008}, pages = {615-623}, publisher = {Blackwell Publishing}, abstract = {

Shrub encroachment into grass-dominated biomes is occurring globally due to a variety of anthropogenic activities, but the consequences for carbon (C) inputs, storage and cycling remain unclear. We studied eight North American graminoid-dominated ecosystems invaded by shrubs, from arctic tundra to Atlantic coastal dunes, to quantify patterns and controls of C inputs via aboveground net primary production (ANPP). Across a 4-fold range in mean annual precipitation (MAP), a key regulator of ecosystem C input at the continental scale, shrub invasion decreased ANPP in xeric sites, but dramatically increased ANPP (\>1000 g/m2) at high MAP, where shrub patches maintained extraordinarily high leaf area. Concurrently, the relationship between MAP and ANPP shifted from being non-linear in grasslands to linear in shrublands. Thus, relatively abrupt (\<50 yrs) shifts in growth form dominance, without changes in resource quantity, can fundamentally alter continental-scale pattern of C inputs and control by MAP in ways that exceed the direct effects of climate change alone.

}, keywords = {aboveground net primary production, carbon, climate change, encroachment, grass-dominated biomes, grasslands, growth form, LAI, MAP, North American, shrub, shrublands}, doi = {10.1111/j.1365-2486.2007.01512.x }, url = {/files/bibliography/08-005.pdf}, author = {A. K. Knapp and J. M. Briggs and S.L. Collins and Steven R. Archer and M.S. Bret-Harte and Ewers, B. and Debra C. Peters and Young, D. and Shaver, G. and Cleary, M.B.} } @book {50242, title = {Snowmelt Runoff Model (SRM) User{\textquoteright}s Manual}, series = {Book}, year = {2008}, month = {February 2008}, pages = {175 pp}, publisher = {New Mexico State University}, organization = {New Mexico State University}, address = {Las Cruces, NM}, abstract = {This 2008 edition of the User{\textquoteright}s Manual presents a new computer program, the Windows Version 1.11 of the Snowmelt Runoff Model (WinSRM). The popular Version 4 is also preserved in the Appendix because it is still in demand to be used within its limits. The Windows version adds new capabilities: it accepts more detailed climate scenarios; for example, different daily changes of temperature and precipitation. It makes possible to substitute a data set of temperatures and precipitation of a selected year as a {\textquotedblleft}climate scenario{\textquotedblright} for any available existing year and evaluate the resulting snow conditions and runoff. A normalized year, including normalized Conventional Depletion Curves (CDC{\textquoteright}s) from long term temperature and precipitation data can be derived to represent today{\textquoteright}s climate. It is now possible to divide a basin into as many as 16 elevation or other zones in order to refine the modeling, while Version 4 only allowed 8. These improvements facilitate new developments in SRM applications which are already taking place: runoff modeling by using different land use zones, separating satellite mapping of snow and glaciers, runoff modeling in very large basins with an extreme elevation range, and others. The specific features of WinSRM Version 1.11 are explained in detail in this document in Sections 8.5, 8.6, 9, and 10. WinSRM Version 1.11 has been developed without sacrificing the advantages of the SRM Version 4, in particular the speed of getting results. Both versions are available on the Internet by accessing http://www.ars.usda.gov/Services/docs.htm?docid=8872. Should this link not be {\textquotedblleft}current{\textquotedblright} for the reader, one can {\textquotedblleft}search{\textquotedblright} on {\textquotedblleft}SRM home{\textquotedblright} or {\textquotedblleft}WinSRM{\textquotedblright} to locate a {\textquotedblleft}current site{\textquotedblright}. So far, four SRM workshops (in 1992, 1994, 1996, and 1998) have been organized at the University of Bern, Switzerland, with about 130 participants from 20 countries taking part. A fifth SRM workshop was organized in 2005 at New Mexico State University. In addition, the authors are available to assist users in overcoming special problems which may be encountered.}, keywords = {snowmelt runoff model, SRM, user{\textquoteright}s manual}, url = {/files/bibliography/08-023.pdf}, author = {J. Martinec and A. Rango and R. T. Roberts} } @inbook {50243, title = {Sustainable allocation of biodiversity to improve human health and well-being}, booktitle = {Biodiversity change and human health: from ecosystem services to spread of disease}, year = {2008}, note = {//OTHER//LTER-V//entered 06/02/2008 per DEPProCite field[6]: In}, month = {2008}, publisher = {Island Press}, organization = {Island Press}, address = {Washington, DC}, keywords = {biodiversity, book, chapter, disease, ecosystem services, human health, report}, author = {Meyerson, L. A. and O. E. Sala and Froment, A. and Friedman, C. and Hund-Rinke, K. and Martens, P. and Mazumder, A. and Purohit, A. and Thomas, M. and Wilby, A.}, editor = {O. E. Sala and Meyerson, L. A. and C. Parmesan} } @article {50247, title = {Spatial variability of soil and nutrient characteristics of semi-arid grasslands and shrublands, Jornada Basin, New Mexico}, journal = {Ecohydrology}, volume = {1}, year = {2008}, note = {//USDA//LTER-V//entered 06/02/2008; PDF on file}, month = {2008}, pages = {3-12}, abstract = {

Heterogeneity of vegetation and soil properties is characteristic of semi-arid and arid environments. The potential underlying causes of the dynamics that create this spatial variability, with consequent impacts on landscape connectivity and thus ecological and ecohydrological processes, are not clearly understood. An investigation was carried out into the spatial variability of ponded infiltration rate, soil moisture, soil-aggregate stability, vegetation cover, random roughness and nutrient content in the soil (ammonium, nitrate and phosphorus) at grassland and shrubland sites for two spatial scales in the Jornada Basin, in the northern part of the Chihuahua desert. At the plant-interplant scale, statistically significant differences exist between vegetated and non-vegetated sites for soil moisture and infiltration rate within both shrublands and grasslands. The spatial distributions of all other parameters follow a more complex scheme at this scale. At the landscape scale, distinct differences exist for most parameters between the grasslands and the shrubland sites. Geostatistical analysis revealed that the autocorrelation lengths are not simply a function of average shrub sizes, but may be caused by a more complex pattern probably related to the spatial layout of rill and inter-rill areas and other localized transfers of soil resources through the redistribution of water and wind. These results demonstrate the importance of understanding spatial linkages of processes within the landscape in understanding dryland ecosystem dynamics. Copyright {\textcopyright} 2007 John Wiley \& Sons, Ltd.

}, keywords = {article, connectivity, desert ecosystems, desertification, grassland, hydrology, Jornada, Jornada Basin, journal, landscape ecology, shrubland, soil characteristics, spatial variability, soil nutrients, spatial variability, spatial variability}, doi = {10.1002/eco.1}, url = {files/bibliography/JRN00515.pdf}, author = {Eva N. M{\"u}ller and John Wainwright and A.J. Parsons} } @article {50248, title = {Spatial analysis of effects of mowing and burning on colony expansion in reintroduced black-tailed prairie dog (Cynomys ludovicianus)}, journal = {Restoration Ecology}, volume = {16}, year = {2008}, month = {09/2008 }, pages = {495-502}, abstract = {

Factors contributing to the expansion of prairie dog (Cynomys spp.) colonies are poorly understood. Models simulating expansion of fossorial mammal populations interacting with the physical environment have shown mixed results. Data of burrow locations, burrow status, entrance type, aspect, and other characteristics were collected over a 4-year period on three study colonies. Several 50 m x 50 m plots were either mowed or burned near the periphery of the 3 colonies to determine the effects of these treatments on colony expansion. Spatial point patterns of burrows were analyzed for the post-treatment period. The overall orientation of new burrow locations was also examined. These analyses dealt exclusively with active burrows since numbers of active burrows are highly correlated with population density. Chi-square analysis suggested that burrows tended to be clustered. Directional analysis showed that colony expansion was oriented towards the treated plots 1 and 2 years after the treatments. K-function plots showed clustering at distances of 5.0 \– 7.0 m. These analyses show that the fire and mowing treatments influence colony expansion. Our results contribute to our current knowledge of the factors both promoting and constraining the expansion of reintroduced prairie dog colonies, and may lead to more effective management of prairie dog colonies following reintroduction.

}, keywords = {fossorial, prairie}, doi = {10.1111/j.1526-100X.2007.00323.x}, url = {/files/bibliography/08-034.pdf}, author = {Northcott, J. and C.A. Anderson and G. Roemer and E.L. Fredrickson and Demers, M. and J. Truett and P. L. Ford} } @article {50251, title = {Spatial patterns of soil nutrients in two southern African savannas}, journal = {Journal of Geophysical Research - Biogeosciences}, volume = {113}, year = {2008}, pages = {G02011}, doi = {10.1029/2007JG000584}, author = {Gregory S. Okin and Mladenov, N. and L. Wang and Cassel, D. and Caylor, K. K. and Ringrose, S. and Stephen A. Macko} } @inbook {50256, title = {Simulation of disturbances and recovery in shortgrass steppe plant communities}, booktitle = {Ecology of the Shortgrass Steepe: A long-term perspective}, year = {2008}, month = {September 2008}, pages = {119-131}, publisher = {Oxford Press}, organization = {Oxford Press}, address = {New York}, abstract = {The objective of this chapter was to evaluate the importance of gap dynamics concepts of succession for understanding shortgrass plant community recovery following disturbances. A gap dynamics approach focuses on individual plants, and the interactions between disturbance characteristics and plant life history traits in explaining successional patterns. We developed a gap dynamics model for shortgrass steppe plant communities (STEPPE) based upon the conceptual and modeling framework provided by forest models, modifying it to represent Great Plains grasslands. We used STEPPE in several capacities: (1) to synthesize and integrate existing knowledge to improve our understanding of recovery processes following disturbance; (2) to identify key processes limiting recovery; and (3) to predict long- term recovery dynamics for different climate and disturbance characteristics, in particular soil texture and disturbance size. Our analyses show that seed dispersal is a key process limiting recovery of the dominant species, blue grama, across a range of disturbance sizes. Our simulation results also indicate the importance of soil properties, especially silt content, to recovery rates of blue grama, and the greater importance of seedling establishment compared to seedling growth; however these hypotheses have yet to be tested in the field.}, keywords = {gap dynamics, recovery, shorgrass plant community}, author = {Debra C. Peters and W. K. Lauenroth} } @inbook {50264, title = {Snow Climatology and Snow Distribution}, booktitle = {Principles of Snow Hydrology}, year = {2008}, month = {July 2008}, pages = {20-47}, chapter = {2}, abstract = {

Processes controlling snowfall amounts and timing are reasonably well understood, but snow hydrologists still must rely on precipitation and snowpack measurements to obtain basic liquid inputs to models. However, it is becoming possible to predict the distribution of snow across landscapes due to effects of blowing snow and vegetation interception. Blowing snow adjustments are especially needed in cold locations with high wind speeds where entire slopes may be swept free of snow while others may be deeply drifted. Basins with a wide variety of land cover types and extensive dense tree and shrub vegetation will also require adjustment for canopy interception due to differences in types of vegetation as well as vegetation density. A simple reduction of snowfall for interception may suffice in some applications, but in others where time and space scales are expanded, accounting for storage of snow in the canopy and gradual sublimation losses and intermittent throughfall releases are needed. Much has been learned, but blowing snow and canopy interception remain two of the most important areas for future snow hydrology research.

}, keywords = {climatology, distribution, measurements, models, precipitation, snow, snowpack}, url = {http://www.cambridge.org/us/academic/subjects/earth-and-environmental-science/hydrology-hydrogeology-and-water-resources/principles-snow-hydrology}, author = {A. Rango and D. DeWalle} } @inbook {50258, title = {Snowmelt Runoff Model (SRM)}, booktitle = {Principles of Snow Hydrology}, year = {2008}, month = {July 2008}, pages = {306-364}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, chapter = {11}, address = {Cambridge, NY}, abstract = {

The Snowmelt-Runoff Model (SRM) is designed to simulate and forecast daily streamflow in mountain basins where snowmelt is a major runoff factor. Most recently, it has also been applied to evaluate the effect of a changed climate on the seasonal snow cover and runoff. SRM was developed by Martinec (1975) in small European basins. Thanks to the progress of satellite remote sensing of snow cover, SRM has been applied to larger and larger basins. The Ganges River Basin in the Himalayas, the largest basin where SRM has been applied so far, is about 917,000 km2(Seidel et al., 2000). Runoff computations by SRM appear to be relatively easily understood. To date, the model has been applied by various agencies, institutes and universities in about 80 basins situated in 25 different countries. About 25\% of these applications have been performed by the model developers and 75 \% by independent users. SRM also successfully underwent tests by the World Meteorological Organization with regard to runoff simulations (WMO, 1986) and to partially simulated conditions of real time runoff forecasts (WMO, 1992). SRM is one of the few hydrological models developed that requires direct inputs derived from remote-sensing data.

}, url = {http://www.cambridge.org/us/academic/subjects/earth-and-environmental-science/hydrology-hydrogeology-and-water-resources/principles-snow-hydrology}, author = {A. Rango and D. DeWalle} } @inbook {50266, title = {Snowpack Management and Modification}, booktitle = {Principles of Snow Hydrology}, year = {2008}, month = {July 7, 2008}, pages = {365-391}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, chapter = {12}, address = {Cambridge, NY}, abstract = {

Snow in the global environment is altered by human activity in many ways, some intentional and others inadvertent. Among the deliberate changes made to snowpacks are blowing snow management to benefit agriculture and transportation, forest management to protect and enhance water yields from snowpacks, urban snow management to improve transportation and habitation in developed areas, albedo modification to enhance snowmelt rates, and ski area management for enhanced and safe recreational opportunities. The major inadvertent change that may impact snowpacks is the possibility of global warming being forecast for the next century. This final chapter generally discusses these human-snow interactions from the viewpoint of the snow hydrologist.

}, keywords = {agriculture, blowing, forest, management, modifications, snowpack}, url = {http://www.cambridge.org/us/academic/subjects/earth-and-environmental-science/hydrology-hydrogeology-and-water-resources/principles-snow-hydrology}, author = {A. Rango and D. DeWalle} } @conference {50288, title = {Soil survey and resource inventory guide for dynamic soil properties and soil change}, booktitle = {Geological Society of America}, series = {2008 Joint Meetings}, year = {2008}, month = {October 5-9, 200}, pages = {756-2}, address = {Houston, TX}, abstract = {Data and information about how soils change are needed by producers, land managers, and decision makers in order to plan for long-term productivity, interpret indicators used in monitoring and assessments, and manage human impacts on soil. In order to meet these needs, the National Cooperative Soil Survey is now including data collection procedures to characterize dynamic soil properties. The new procedures are based on simple conceptual models of management effects on soil, integrated soil and vegetation (where present) data collection, and replicate sampling at multiple scales. A cooperative effort to develop sampling guidelines was initiated in 2004. NRCS, working with the Agricultural Research Service Jornada Experimental Range, National Park Service, Forest Service, and Bureau of Land Management has developed the {\textquotedblleft}Soil Survey and Resource Inventory Guide for Dynamic Soil Properties and Soil Change{\textquotedblright}. Data collection will be organized within projects to document land use or management effects on extensive, ecologically or economically important, or benchmark soils. Comparison study projects, which are designed to characterize dynamic soil properties for one or more land cover types or management systems, include the following six steps: 1) Project Planning, 2) Sampling Design, 3) Sampling Requirements, 4) Field Work, 5) Data Preparation, and 6) Data Analysis and Interpretation. These steps are described in this poster.}, keywords = {dynamic soil properties, inventory, long-term productivity, soil survey}, author = {A.J. Tugel and Jeffrey E. Herrick and S.A. Wills and M.D. Remmenga and Biggam, P. and K. Hipple} } @article {50316, title = {Sand flux simulations at a small scale over a heterogeneous mesquite area of the northern Chihuahuan Desert}, journal = {Journal of Applied Meteorology and Climatology}, volume = {46}, number = {9}, year = {2007}, note = {//USDA//LTER V//entered 08/19/2008/ PDF on file}, month = {2007}, pages = {1410-1422}, abstract = {

Within areas of the Chihuahuan Desert dominated by honey mesquite bushes (Prosopis glandulosa), soil erosion causes open eroded patches and the formation of large coppice dunes. The airflow patterns around the dunes and through the open areas are correlated with sand flux and erosion. This study uses wind velocity simulations from the Quick Urban and Industrial Complex (QUIC) model in combination with a sand flux parameterization to simulate sand fluxes for each of eight storms occurring in the springs of 2003 and 2004. Total sand fluxes based on the sum of all the sand collectors located within the study domain were usually within 50\% of the measured values for each of the storms, with simulations for individual sand collectors also often within 50\% of the measured values. Simulated fluxes based on two different sand flux parameterizations were generally within 10\% of each other, differing substantially only when the sand flux was low (near the threshold velocity). Good agreement between the field observations with a Sensit instrument and QUIC simulations for the same location and time series suggests that QUIC could be used to predict the spatial and temporal variation of sand flux patterns for a domain.

}, keywords = {aeolian processes, erosion, aeolian processes, M-NORT, aeolian processes, mesquite dunes, aeolian processes, model, aeolian processes, NPP sites, aeolian processes, QUIC, aeolian processes, sand flux, article, journal, model, QUIC, NPP sites, aeolian processes}, doi = {10.1175/JAM2537.1}, url = {files/bibliography/JRN00481.pdf}, author = {Bowker, George E. and D. E. Gillette and Gilles Bergametti and B{\'e}atrice Marticorena and Heist, David K.} } @article {50347, title = {Sampling for natural resource monitoring: Book review}, journal = {Soil Science Society of America Journal}, volume = {71}, number = {4}, year = {2007}, note = {Book review published online}, month = {06/2007}, pages = {1421}, type = {Literature Review}, abstract = {

Sampling for Natural Resource Monitoring provided a comprehensive introduction to natural resource sampling design for students, scientists, and managers.\  Following a brief introduction. \ The book begins with a section summarizing the principles and major decisions required to develop an effective sampling strategy.\  The remainder of the book is divided among three sections addressing sampling in space (for surveys), and in time and space-time (for monitoring).\  Each of these sections includes chapters on sampling for global and local quantities in space.\  Within each chapter, the author\’s describe both \“design-based\” approaches of classical survey sampling and \“model-based\” approaches associated with geostatistics and time series analysis.\  Inclusion of both types of approaches in a single volume allows the authors to show how they can complement each other.\  For example, spatial models can be used to optimize sample sizes for design-based sampling strategies.\  Detailed appendices provide additional information on optimization algorithms, kriging, and time-series modeling.

}, keywords = {monitoring, natural resource, review article, sampling}, url = {/files/bibliography/07-038.pdf}, author = {Jeffrey E. Herrick} } @conference {50348, title = {Science-based integrated assessment and monitoring of OHV effects on soils and vegetation}, booktitle = {Society for Range Management, 60th Annual Meeting and Trade Show}, year = {2007}, month = {02/09/2007}, pages = {Paper. No. 195}, address = {Reno/Sparks, NV}, abstract = {Off-highway vehicles (OHVs) negatively affect multiple rangeland ecosystem services by modifying soil structure and plant community composition, structure, and productivity. They can introduce invasive species, and increase runoff, soil erosion and plant mortiality. The extent to which long-term degradation occurs depends on the type, timing and intensity of distrubances, and on degradation resistance and recovery potential. As OHV activity increases, limited management must be focused on those areas where OHVs are having the greatest impacts, and where these impacts can be cost-effectively prevented or mitigated. Systematic protocols are required to identify and prioritize OHV impacted areas. We are developing a science-based integrated strategy for identifying, assessing, and monitoring OHV effects on fundamental soil and vegetation attributes on which nearly all ecosystem services depend. This strategy includes four elements. (1) Landscape stratification based on ecological potential. (2) Identification of appropriate assessment and monitoring scales based on the scale of the impacts relative to the scale of soil and vegetation variability. (3) Assessment of current status relative to ecological potential and possible thresholds. (4) Selection of appropriate monitoring indicators based on quantitative relationships between these indicators and critical ecosystem services for different types of soil and vegetation. The forth element shows that OHV tracks dramatically reduce infiltration on some soils and plant species but have virtually no effect on others. For thsoe soils and plant communities where infiltration is affected, recovery rates also vary significantly.}, keywords = {ecosystem, off-highway vehicles, OHV, rangeland, soils, vegetation}, author = {Jeffrey E. Herrick and D.A. Pyke and Danielle Duni} } @article {50346, title = {A strategy for ecology in an era of globalization}, journal = {Frontiers in Ecology and the Environment}, volume = {5}, year = {2007}, month = {05/2007}, pages = {172-181}, abstract = {

Globalization of labor and capital can increase the rate and extent of global environmental degradation, while enhancing the ability of ecologists to respond rapidly and collaboratively to mitigate these impacts. Nevertheless, ecological research remains focused at local and regional levels, with collaboration limited by national borders and funding. New initiatives are required to increase the utility and availability of environmental research to natural resource owners, managers, and policy makers in the public and private sectors, whose decisions affect land and other forms of natural capital. We propose a four-part strategy to increase the effectiveness of ecological science in addressing environmental issues in an era of globalization: (1) develop an Ecological Knowledge System, (2) increase our ability to anticipate, identify, and rapidly address new research needs, (3) increase the number and diversity of participants in all phases of research and decision-making processes, and (4) increase the flexibility of funding sources.

La globalizaci{\'o}n de la fuerza de trabajo y del capital puede aumentar el {\'\i}ndice y el grado de degradaci{\'o}n ambiental global y al mismo tiempo mejorar la capacidad de los ec{\'o}logos para mitigar sus efectos negativos. Sin embargo, la investigaci{\'o}n ecol{\'o}gica sigue enfocada a una escala local fuera del contexto global, y la colaboraci{\'o}n profesional y de investigaci{\'o}n est{\'a} seriamente limitada por fronteras nacionales y por falta de financiamiento. Se requieren nuevas iniciativas para aumentar la utilidad y la disponibilidad de la investigaci{\'o}n ambiental a los due{\~n}os, a los encargados y a los pol{\'\i}ticos a cargo del manejo y conservaci{\'o}n de recursos naturales en los sectores p{\'u}blicos y privados, cuyas decisiones afectan las tierras y otras formas del capital natural de un pa{\'\i}s. Con el fin de aumentar la eficacia de las ciencias ecol{\'o}gicas para tratar con los temas ambientales en una era de globalizaci{\'o}n, proponemos una estrategia compuesta por cuatro partes: (1) El desarrollo de un Sistema de Conocimientos Ecol{\'o}gicos (EKS), (2) El incremento de nuestra capacidad de anticipar, identificar y atender r{\'a}pidamente nuevas necesidades dentro de la investigaci{\'o}n, (3) El aumento del n{\'u}mero y la diversidad de participantes en todas las fases de los procedimientos de la investigaci{\'o}n y la toma de decisiones, y (4) El aumento de la sensibilidad y la flexibilidad de las fuentes de financiamiento hacia este tipo de investigaci{\'o}n ecol{\'o}gica enfocada a resolver problemas multidisciplinarios concretos.

}, keywords = {ecology, era, globalization, strategy}, doi = {10.1890/1540-9295(2007)5[172:ASFEIA]2.0.CO;2}, url = {/files/bibliography/07-021.pdf}, author = {Jeffrey E. Herrick and J. Sarukhan} } @mastersthesis {50357, title = {Small-scale erosion-driven nutrient dynamics in different vegetation communities in Jornada, New Mexico: implications for land degradation}, year = {2007}, note = {//USDA//LTER-V//entered 08/15/2007ProCite field[12]: Not in File}, month = {2007}, school = {Bristol University}, address = {Bristol University}, keywords = {dissertation, hydrology, erosion, hydrology, nutrients, land degradation, erosion, land degradation, hydrology, land degradation, nutrients, thesis}, author = {Lister, Debbie} } @article {50363, title = {The stability of vegetation boundaries and the propagation of desertification in the American Southwest: a modelling approach}, journal = {Ecological Modelling}, volume = {208}, year = {2007}, note = {//NMSU, USDA//LTER-V//entered 08/15/2007; updated 11/20/2007}, month = {2007}, pages = {91-101}, abstract = {

A process-based approach to spatially distributed, overland-flow modelling is employed to assess the impact of water and nutrient redistribution at the landscape scale caused by short, high-intensity rainstorm events across grassland{\textendash}shrubland vegetation boundaries of a semi-arid ecosystem in the south-western United States. The modelling scenarios showed that simulated fluxes from shrubland into grassland lead to a gain of water resources but to a loss of nutrient resources in the grassland areas close to the boundary. Simulated fluxes from grasslands into shrublands do not lead to a gain of water resources, but to an increase of nutrient resources for the shrubland areas close to the boundary. On the basis of the modelling results, a new hypothesis for the on-going desertification process in the southwestern United States is proposed. It is hypothesised that a vegetation boundary is stable when two conditions prevail to balance the lower resistance of grassland within the existing environmental setting with the higher resistance of shrubland: that the depletion of soil nutrients by the action of overland flow in the grassland zone close to the boundary is in balance with the replenishment rates of grassland by other nutrient cycling, and that the grassland gains enough water resources from the upslope shrublands. In contrast, a vegetation boundary potentially becomes unstable when the grassland acquires a competitive disadvantage towards shrubland regarding water benefit and nutrient depletion due to the combined effects of overland-flow dynamics and some external forces such as extensive overgrazing or climate change. The modelling results suggest that landscape linkages through the redistribution of water and soil resources across vegetation-transition zones at the landscape scale and feedback dynamics of overland-flow processes play a significant role in the persistence of land degradation in the US Southwest. {\textcopyright} 2007 Elsevier B.V. All rights reserved.

}, keywords = {article, desertification, hydrology, connectivity, hydrology, ecotones, hydrology, grassland, hydrology, model, hydrology, nutrient resources, hydrology, shrubland, journal, model, desertification, model, overland flow, model, vegetation boundaries, vegetation boundaries}, doi = {10.1016/j.ecolmodel.2007.04.010}, url = {files/bibliography/JRN00486.pdf}, author = {Eva N. M{\"u}ller and John Wainwright and A.J. Parsons} } @conference {50369, title = {Soil-vegetation feedbacks in dynamic landscapes: Implications for restoration}, booktitle = {Ecological Society of America Abstracts}, year = {2007}, month = {August 5-10, 200}, pages = {PS 45-80}, address = {San Jose, CA}, abstract = {State changes from perennial grasslands to shrub-dominated systems characterize much of the arid regions of the world, including the American Southwest. Where this conversion is associated with a change in soil surface texture, near-surface water availability can be increased or reduced with important consequences for restoration of perennial grasses. Loss of soil from one area results in deposition in downslope or downwind areas. Little is known about these spatial connections, and how erosion-deposition patterns influence seedling establishment and recovery of perennial grasses. Our objective was to evaluate how soil erosion-associated changes in surface soil texture influence the probability of seedling establishment of the perennial grass, black grama, across a range of initial soil textures. We used a simulation model of daily soil water dynamics (SOILWAT) to simulate recruitment probabilities of this species for the variation in initial soil texture found at the Jornada Basin ARS-LTER site in southern New Mexico. Vegetation and landform maps combined with soils, vegetation, and weather data were used to parameterize the model. Simulated recruitment probabilities were generally higher where near-surface water holding capacity was higher. However, in some cases deposition of small amounts of coarse-textured material (lower water holding capacity) on a relatively fine-textured (higher water holding capacity) site increased establishment due to reduced evaporative losses. We used a wind model to determine spatial patterns in soil loss and deposition at the landscape scale, and displayed our recruitment results for the Jornada Basin. Locations with the largest changes in soil surface texture as a result of wind had the largest changes in recruitment probabilities. Our results show that wind erosion and deposition patterns have strong influences on patterns in seedling establishment.}, keywords = {perennial, shrub-dominated, soil vegetation}, author = {Debra C. Peters and Jeffrey E. Herrick and Curtis H. Monger and Gregory S. Okin} } @inbook {50371, title = {Spatial nonlinearities: Cascading effects in the earth system}, booktitle = {Terrestrial Ecosystems in a Changing World}, year = {2007}, month = {2007}, pages = {165-174}, publisher = {Springer Verlag}, organization = {Springer Verlag}, address = {Berlin, Germany}, abstract = {Nonlinear interactions and feedbacks associated with thresholds through time and across space are common features of biological, physical and materials systems. These spatial nonlinearities generate surprising behavior where dynamics at one scale cannot be easily predicted based on information obtained at finer or broader scales. These cascading effects often result in severe consequences for the environment and human welfare (i.e., catastrophes) that are expected to be particularly important under conditions of changes in climate and land use. In this chapter, we illustrate the usefulness of a general conceptual and mathematical framework for understanding and forecasting spatially nonlinear responses to global change. This framework includes cross-scale interactions, threshold behavior and feedback mechanisms. We focus on spatial nonlinearities produced by fine-scale processes that cascade through time and across space to influence broad spatial extents. Here we describe the spread of catastrophic events in the context of our cross-disciplinary framework using examples from biology (wildfires, desertification, infectious diseases) and engineering (structural failures) and discuss the consequences of applying these ideas to forecasting future dynamics under a changing global environment.}, keywords = {desertification, nonlinearities, wildfires}, author = {Debra C. Peters and R.A. Pielke and Brandon T Bestelmeyer and C.D. Allen and Seth M. Munson and Kris Havstad}, editor = {J. Canadell and D.E. Pataki and Pitelka, L.} } @article {50389, title = {Support vector machines for recognition of semi-arid vegetation types using MISR multi-angle imagery}, journal = {Remote Sensing of Environment}, volume = {107}, year = {2007}, note = {//USDA//LTER V//entered 04/18/2008; PDF on file}, month = {2007}, pages = {299-311}, abstract = {

Accurately mapping community types is one of the main challenges for monitoring arid and semi-arid grasslands with remote sensing. The multi-angle approach has been proven useful for mapping vegetation types in desert grassland. The Multi-angle Imaging Spectro-Radiometer (MISR) provides 4 spectral bands and 9 angular reflectance. In this study, 44 classification experiments have been implemented to find the optimal combination of MISR multi-angular data to mine the information carried by MISR data as effectively as possible. These experiments show the following findings: 1) The combination of MISR\&$\#$39;s 4 spectral bands at nadir and red and near infrared bands in the C, B, and A cameras observing off-nadir can obtain the best vegetation type differentiation at the community level in New Mexico desert grasslands. 2) The k parameter at red band of Modified\–Rahman\–Pinty\–Verstraete (MRPV) model and the structural scattering index (SSI) can bring useful additional information to land cover classification. The information carried by these two parameters, however, is less than that carried by surface anisotropy patterns described by the MRPV model and a linear semi-empirical kernel-driven bidirectional reflectance distribution function model, the RossThin\–LiSparseMODIS (RTnLS) model. These experiments prove that: 1) multi-angular reflectance raise overall classification accuracy from 45.8\% for nadir-only reflectance to 60.9\%. 2) With surface anisotropy patterns derived from MRPV and RTnLS, an overall accuracy of 68.1\% can be obtained when maximum likelihood algorithms are used. 3) Support Vector Machine (SVM) algorithms can raise the classification accuracy to 76.7\%. This research shows that multi-angular reflectance, surface anisotropy patterns and SVM algorithms can improve desert vegetation type differentiation importantly.

}, keywords = {classification, MISR, multi-angle observations, semi-arid vegetation, support vector machine}, doi = {10.1016/j.rse.2006.05.023}, url = {/files/bibliography/07-004.pdf}, author = {L. Su and M. Chopping and A. Rango and J. V. Martonchik and Debra C. Peters} } @conference {50394, title = {Sampling dynamic soil properties and vegetation for soil survey and ecological site descriptions}, booktitle = {Society for Range Management 60th Annual Meeting and Trade show}, year = {2007}, month = {02/09/2007}, pages = {Paper No. 444}, address = {Reno/Sparks, NV}, abstract = {Dynamic soil property data can be collected during soil survey updates to add value to soil survey products and meet users needs for ecological site descriptions. Producers and land managers need information about soil and ecosystem change in order to plan for long-term productivity, conduct monitoring and assessments, and predict management effects on soil. Data collection technologies that can be used in the soil survey program are, however, not fully developed. A cooperative effort to develop sampling guidelines was initiated in 2004. NRCS is developing guidelines in cooperation with the Jornada Experimental Range (ARS), National Park Service, Forest Service and Bureau of Land Management. The guide for Sampling Dynamic Soil Properties integrates soil and vegetation data collection and interpretation. The guide emphasizes functionally important properties, field methods, and efficiency.}, keywords = {BLM, ecological site descriptions, ESD, JER, NPS}, author = {A.J. Tugel and J.P. Ward and Jeffrey E. Herrick and Biggam, P. and K. Hipple and Ypsilantes, B. and Davis, R.} } @conference {50396, title = {Sheep and goats as tool to suppress juniper encroachment: Influence of stocking density and mixed grazing during summer}, booktitle = {Society for Range Management Annual Meeting}, year = {2007}, month = {February 9-16, 2}, pages = {Paper No. 447}, address = {Reno/Sparks, NV}, abstract = {Grazing trials were conducted to evaluate the use of prescribed grazing by sheep and goats to suppress one-seed juniper (Juniperus monosperma Englem. Sarg.) sapling reinvasion. A 2x2 factorial experiment was conducted with Goats (G) or Goats + Sheep (G+S) at high or low stocking densities (SD). Ten crossbreed Angora nannies (1.1 AU) or 5 nannies of the same breed mixed with 4 Ramboullet ewes (1.1 AU) grazed either 1 juniper invaded plot of 20 x 30 m for 6 days (LD) or 6 similar subplots of 10 x 10 m for 1 day (HD) in each of 2 blocks. Animals grazed from sunrise to sunset, were penned at night and received a protein supplement (45\% CP) at a rate of 0.4\% BW, daily. No effect of SD, herbivore (G, G+S), or their interaction was found on juniper utilization. Animals removed on average 38.3\% of the length of marked juniper sapling branches. Understory grazing intensity differed between G or G+S (P=0.02) and SD (P=0.05) treatments. G+S removed 71.3 \% of the available herbaceous biomass whereas G removed 64.7 \%. Greater understory grazing intensity was observed under LD (70.4 \%) compared to HD (65.0 \%). Goats spent more time feeding on juniper compared to sheep (Goats: 24.5\%, Sheep: 7.7\%, P<0.01), whereas the opposite occurred with herbaceous vegetation (Goats: 76.0 \%, Sheep: 92.3 \%; P< 0.01). Stocking density did not influence time spent feeding juniper or herbaceous understory (P=0.08). Goats in HD and LD grazing treatments spent similar time feeding on juniper (P=0.09). Prescribed high density grazing with goats alone, rather than goats and sheep, could promote acceptable juniper sapling use along with lower damage on herbaceous vegetation. Juniper sapling responses to the treatments imposed in this study will be monitored through time.}, keywords = {goats, grazing, one-seed juniper, sheep}, author = {S. A. Utsumi and Andr{\'e}s F. Cibils and Richard E. Estell} } @article {50400, title = {Seed harvester ants (Polonomyrmex rugosus) as "pulse" predators}, journal = {Journal of Arid Enviornments}, volume = {70}, year = {2007}, month = {03/2007}, pages = {549-552}, abstract = {Seed harvesting ants, Pogonomyrmex rugosus, collected grass cicadas at a high rate (\>5 min-1 taken into the nest) at one location where cicada emergence exceeded 3m-2. Dry conditions in the winter-spring resulted in no annual plants in the northern Chihuahuan Desert. P. rugosus colonies were inactive in areas where grass cicada emergence was less than 1 m-2. P. rugosus initiate intense predatory activity in response to pulse of large numbers of prey. This study demonstrates that predatory behavior of seed harvesting ants is not limited to incidental encounters with prey during seed harvesting activities. Pulse predation demonstrates the importance of protein to seed harvester ant colonies.}, keywords = {Beameria vanosa, forage ecology, grass cicadas}, doi = {10.1016/j.jaridenv.2007.01.005}, url = {/files/bibliography/07-015.pdf}, author = {Walter G. Whitford and E. Jackson} } @proceedings {50410, title = {Symbiotic fungi that influence vigor, biomass and reproductive potential of native bunch grasses for remediation of degraded semiarid rangelands}, year = {2006}, month = {June 6-8, 2006}, address = {Cedar City, UT}, abstract = {A steady decline of perennial bunch grasses in arid rangelands has resulted in losses of productivity and germplasm. Remediation is costly and rarely successful. Cryptic symbiotic fungi, structurally integrated with cells and organs of native plants cannot be separated from host plant tissue. However, they were successfully transferred from cell cultures of native plants to other native grasses and tomato. Fungi in recipient plants were heritable and substantially enhanced vigor, biomass and reproductive potential. The transfer of novel fungal symbionts to other native or crop plants may offer an alternative method of improving plant performance without modifying native plant germplasm.}, keywords = {fungi, Symbiotic}, author = {J.R. Barrow and M.E. Lucero and I. Reyes-Vera} } @article {50417, title = {Soil-Geomorphic Heterogeneity Governs Patchy Vegetation Dynamics at an Arid Ecotone}, journal = {Ecology}, volume = {87}, number = {4}, year = {2006}, month = {April 2006}, pages = {963-973}, abstract = {

Soil properties are well known to affect vegetation, but the role of soil heterogeneity in the patterning of vegetation dynamics is poorly documented. We asked whether the location of an ecotone separating grass-dominated and sparsely-vegetated areas reflected only historical variation in degradation or was related to variation in inherent soil properties. We then asked whether changes in the cover and spatial organization of vegetated and bare patches assessed using repeat aerial photography reflected self-organizing dynamics unrelated to soil variation or the stable patterning of soil variation. We found that the present-day ecotone was related to a shift from more weakly to more strongly developed soils. Parts of the ecotone were stable for over 60 year, but shifts between bare and vegetated states, as well as persistently vegetated and bare states, occurred largely in small (\<40 m2) patches throughout the study area. The probability that patches were presently vegetated or bare, as well as the probability that vegetation persisted and/or established over the 60 year period, was negatively related to surface calcium caronate and positively related to subsurface clay content. Thus, only a fraction of the landscape was susceptible to vegetation change and the sparesely-vegetated area likely featured a higher frequency of susceptible soil patches. Patch dynamics and self-organizing processes can be constrained by subtle (and often unrecognized) soil heterogeneity.

}, keywords = {autocorrelation, Chihuahuan Desert, patch dynamics, rangeland, self-organization, state-and-transition model, threshold}, doi = {10.1890/0012-9658(2006)87[963:SHGPVD]2.0.CO;2}, url = {/files/bibliography/06-015.pdf}, author = {Brandon T Bestelmeyer and J.P. Ward and Kris Havstad} } @conference {50424, title = {Shrub encroachment across North America: A multi-site synthesis of patterns, mechanisms, and consequences}, booktitle = {91st Ecological Society of America Meetings}, year = {2006}, month = {August 6-11, 200}, pages = {99}, address = {ProCite field[13]: Memphis, TN}, abstract = {In North America, the expansion of shrubs within ecosystems previously dominated by herbaceous species has been documented in barrier islands off the Virginia coast, mesic grasslands of the Great Plains, sub-tropical savannas of Texas, desert grasslands of the Southwest, across the Intermountain West and in the Artic tundra. We synthesized data from four LTER sites and seven sites in total (in Virginia, Kansas, Texas, New Mexico, Wyoming and Alaska) to assess the mechanisms and consequences of this widespread pattern of growth-form substitution. Mean annual temperature at these sites ranged from -12.5C at the tundra site (Arctic LTER) to 22C at the La Copita, TX site and mean annual precipitation (MAP) ranging from 259mm at the WY site to 1065mm at the Virginia Coast Reserve LTER site. Overall, ANPP was increased when shrubs invaded herbaceous-dominated ecosystems, but this pattern was driven by large increases at the mesic sites. At the driest sites (NM and WY), ANPP decreased with shrub expansion. Across all sites, MAP was more strongly correlated with shrub ANPP (r2 = 0.71) than herbaceous ANPP (r2 = 0.55). In contrast to ANPP responses, species richness declined with the expansion of shrubs into these herbaceous-dominated ecosystems. These shifts in ecosystem structure clearly affect function across these biomes, with potentially dramatic and long-term regional implications given the extent of this phenomenon and the low probability of a return to dominance by herbaceous species in many of these ecosystems.}, keywords = {grasslands, shrub, sythesis}, author = {J. M. Briggs and A. K. Knapp and Steven R. Archer and M.S. Bret-Harte and S.L. Collins and Ewers, B. and Debra C. Peters and Young, D.} } @article {50445, title = {Spatial prediction of invasion success across heterogeneous landscapes using an individual-based model}, journal = {Biological Invasions}, volume = {8}, year = {2006}, note = {This record is duplicated by $\#$161851 which should not be used for reporting or appraisal purposes.}, month = {March 2006}, pages = {193-200}, abstract = {

We used an individual-based simulation model (ECOTONE) in conjunction with climate and soil texture data in a GIS to identify grassland sites in Colorado where the invasive perennial forb, Acroptilon repens (Russian knapweed), is likely to be successful. We also created a threat map indicating the most vulnerable regions for future invasion within the state. This species is a serious problem throughout western rangelands of the U.S. and Canada. Our results show that A. repens has the potential to become most abundant in dry areas with fine-textured soils. Validation of model results with existing infested sites shows that additional areas are at risk from invasion. This information can be used to direct management efforts towards the areas at greatest risk, allowing the most effective use of limited resources.

}, keywords = {acroptilon repens, climate, Colorado, geographic information systems, grassland, grassland sites, individual-based simulation model, invasion, Russian knapweed, soil texture, spatial prediction}, doi = {10.1007/s10530-004-2954-y}, url = {/files/bibliography/06-020.pdf}, author = {Sarah Goslee and Debra C. Peters and Beck, K.G.} } @article {50452, title = {Selected Essays on Science, Rangelands, and Roles of the Society for Range Management, Volume II}, journal = {Rangelands}, volume = {28}, year = {2006}, month = {08/2006}, pages = {35-38}, chapter = {35}, abstract = {This is a second set of essays that address topics of concern to rangeland science, and the profession of rangeland management. This set of essays primarily focuses on phenomena related to climate change. There are many recent reports where changes in climate at regional to global scales have been quantified. For example, warming during the winter months of the Earth{\textquoteright}s Antarctic troposphere has been observed at 0.5-0.7 degrees C per decade over the last 30 years. Recent studies have also documented dramatic increases in discharges of glaciers tied to polar ice sheets in both the northern and southern hemispheres. Most of these changes re presumed to be linked to present level of atmospheric carbon dioxide of 380 parts per million, up from the preindustrial level of the 19th Century of 290 ppm. The USDA, Agricultural Research Service, as well as other research programs in the western US, are addressing objectives for adapting to dynamic environments. There are a number of current research projects generating data sets related to coping with drought, contending with shifting vegetation structure and composition, plant responses to elevated atmospheric CO2 levels, and relationships of vegetation to water yields. These projects will be crucial for informing adaptation of policies and resource management in response to changing climates.}, keywords = {climate change, global scales, rangeland management, rangeland science}, doi = {10.2111/1551-501X(2006)28[35:SEOSRA]2.0.CO;2}, url = {/files/bibliography/06-043.pdf}, author = {Kris Havstad} } @booklet {50450, title = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {492}, publisher = {Oxford University Press}, address = {New York, NY}, abstract = {

This book is a synthesis of the arid rangeland research conducted in southern New Mexico for nearly a century. The Jornada Basin is truly a long-term research site, and this history is reflected in the databases described in many of the chapters in this book. Research in this basin formally began in 1912 with the creation by Presidential Order within the US Department of Agriculture of the 77,000-ha Jornada Range Reserve. Early publications, primarily USDA bulletins or journal articles in Ecology and the Botanical Gazette, appeared in print beginning in 1917. Researchers such as C.L. Forsling, J.T. Jardine, R.S. Campbell, and R.H. Canfield authored many of these early works, which are both classics in rangeland management and part of the foundation of studies decades later. The creation in 1927 of the Chihuahuan Desert Rangeland Research Center (initially known as the College Ranch) under the jurisdiction of New Mexico State University on 24,000 ha adjacent to the Jornada Range established the 101,000-ha area for long-term research in the basin that operates today. This history of research during the early twentieth century had numerous themes. Much of the early emphasis was on management related to agricultural production. Many of the principles that have been developed about livestock grazing management and rangeland improvement practices in the southwestern US and for arid lands in general can be traced to studies in the Jornada Basin. Yet, during these earlier decades there were also classic papers published on vegetation dynamics, resource redistribution, and small-mammal ecology. Over 40 years ago the first interdisciplinary studies were initiated; these studies served as a forerunner for the collaborative studies of the International Biological Programme (IBP) of the 1970s and those of the Jornada Basin that continue today. This 18-chapter book concludes with a description of future research for important issues in the twenty-first century

}, keywords = {Chihuahuan Desert, ecosystem, Jornada Basin, LTER, synthesis book}, url = {files/bibliography/JRN00461.pdf}, author = {Kris Havstad and L. Huenneke and W. H. Schlesinger}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @conference {50461, title = {A soil-based framework for integrating and applying knowledge of land degradation proceses to assessment, monitoring and management}, booktitle = {World Congress of Soil Science}, number = {Paper No. 53-5}, year = {2006}, month = {July 11, 2006}, address = {Philadelphia, PA}, abstract = {We describe a soil-based framework for organizing, synthesizing, and applying our growing understanding of land degradation processes to assessment, monitoring, and management. The framework is dual-purpose: (1) coordinate the use of existing tools, resources, and knowledge, and (2) facilitate the integration and application of new knowledge as it is developed. The framework includes five elements: (1) an ecological site-based approach to grouping soils based on functional characteristics, (2) a repository for ecological site-specific data and knowledge, (3) conceptual models that organize information on management and restoration options, and protocols for (4) assessing and (5) monitoring key ecosystem attributes. The first two elements already exist for U.S. soils dominated by grassland, shrubland and savanna ecosystems. This paper focuses on the use of conceptual state-and-transition models (element 3) to identify indicators of key properties and processes associated with land degradation and recovery (elements 4 and 5), and to define and communicate appropriate land management and restoration strategies. Development and application of these models provides an opportunity for soil scientists and ecologists to integrate and communicate our knowledge of soil and land degradation processes throughout the world. We will present examples showing how these models are currently being applied to the development of assessment and monitoring programs, and to the prioritization of research.}, keywords = {assessment, land degradation, monitoring}, author = {Jeffrey E. Herrick and Brandon T Bestelmeyer and Joel R. Brown and A.J. Tugel} } @proceedings {50467, title = {Separating Green and Senescent Vegetation in Very High Resolution Photography Using an Intensity-Hue-Saturation Transformation and Object Based Classification}, year = {2006}, month = {May 1-5, 2006}, pages = {CDROM}, address = {Reno, NV}, abstract = {
In arid regions of the southwestern US, grass cover is typically a mixture of green and senescent plant material. It is important that both types of vegetation can be quantified for land management purposes and for assessing the nutritional value of grasses. Traditional ground sampling procedures are commonly used but are time consuming. Our goal was to develop an image analysis approach for separating and quantifying green and senescent grasses in the same plot using very high resolution ground photography. The study was conducted in New Mexico at the Jornada Experimental Range (JER), operated by the USDA Agricultural Research Service. We used an eight megapixel digital camera to acquire ground photography from a height of 2.8 m above ground for fifty plots. The images were transformed from the RGB (red, green, blue) color space to the IHS (intensity, hue, saturation) color space. We used an object-based image analysis approach to classify the images into soil, shadow, green vegetation, and senescent vegetation. Shadow and soil were masked out by using the intensity and saturation bands, and a nearest neighbor classification was used to separate green and senescent vegetation using intensity, hue and saturation as well as visible bands. Correlation coefficients between ground-and image-based estimates for green and senescent vegetation were 0.88 and 0.95 respectively, and image analysis underestimated total and senescent vegetation by approximately 5\%. The image-based approach is a viable alternative to and less labor and time intensive than ground based plot measures. Research into further automation of the image analysis procedures is ongoing.
}, keywords = {intensity-hue-saturation, senescent, vegetation}, url = {/files/bibliography/06-071Proc.pdf}, author = {Andrea S. Laliberte and A. Rango and E.L. Fredrickson} } @inbook {50479, title = {Soil Development in the Jornada Basin}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem. The Jronada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {81-106}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {4}, address = {New York, NY}, abstract = {Soils of the Jornada Basin are the substrate on which Jornada ecosystems reside and interact. Understanding soils and plant-soil feedback processes have been integral to understanding vegetation change and desertification. Formal studies of Jornada soils extend back to 1918. The most detailed study of Jornada soils is the USDA-SCS Desert Soil-Geomorphology Project, a 400-mi2 study area that includes the southernmost areas of the Jornada Experimental Range (JER) and Chihuahuan Desert Rangeland Research Center (CDRRC). This chapter highlights findings of soil and geomorphology studies, discusses factors and processes of soil development, and lists several ways soils of the Jornada Basin carry a memory of past climates.}, keywords = {change, desertification, development, soil, vegetation}, url = {/files/bibliography/06-055.pdf}, author = {Curtis H. Monger}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @article {50478, title = {The Soil-geomorphic template and biotic change in arid and semi-arid ecosystems}, journal = {Journal of Arid Environments}, volume = {65}, year = {2006}, month = {April 1, 2006}, pages = {207-218}, abstract = {

Desertification, characterized as biotic change toward a degraded state, is a common phenomenon in many arid and semiarid regions of the world. Such biotic change is often accompanied by and linked to geomorphic change. Important geomorphic factors that determine the vulnerability of a system to coupled biotic and abiotic change includes soil, topography, and soil parent material{\textemdash}which together form the soil-geomorphic template. Soil exerts control because it is the substrate that provides water, nutrients, anchorage for roots, and habitat for burrowing animals. Topography exerts control by its influence on microclimate via water redistribution, aspect, and elevation. Soil parent material exerts control by its contribution to the nutrient supply and formation of soil. Numerous linkages and feedback-loops occur between the soil-geomorphic template, micro-climate, vegetation, and animals. A perturbation in any of these factors can steer an ecosystem from one state to another. Some soil-geomorphic templates are more prone to change than others. For example, landscapes with sandy soils are more vulnerable to desertification than landscapes with fine-textured soils that receive run-in water and, therefore, require distinct management practices. Desertification involving simultaneous changes in biotic and geomorphic processes provides a good example of how biological and geological systems are coupled and co-evolve.

}, keywords = {biotic, change, desertification, geomorphic, soil, topography}, doi = {10.1016/j.jaridenv.2005.08.012}, url = {/files/bibliography/06-008.pdf}, author = {Curtis H. Monger and Brandon T Bestelmeyer} } @article {50488, title = {Spatial variation in remnant grasses after a grassland-to-shrubland state change: Implications for restoration}, journal = {Rangeland Ecology and Management}, volume = {59}, year = {2006}, month = {July 2006}, pages = {343-350}, abstract = {

Around the world rangelands that have been degraded, such as historical desert grasslands now dominated by woody shrubs, are resistant to restoration efforts. The goal of this descriptive research was to examine the potential for black grama (Bouteloua eriopoda [Torr.] Torr.) recovery by remnant plants in a degraded area as a function of plant location across a landscape. Our objectives were 1) to document the historical dominant vegetation as a perennial grassland and determine broad-scale changes in dominance through time and 2) to examine fine-scale patterns of black grama presence and basal area with respect to microenvironmental conditions that indicate the landscape positions favorable for restoration. Historical vegetation maps starting in 1858, a field survey in 2002{\textendash}2003 of the location of all individual black grama plants in a 29-ha area, and spatial data layers in a geographic information system were used to address these objectives. Upland grasses, including black grama, dominated the study site in 1858, although tarbush (Flourensia cernua DC.) was the dominant species by 1915, and creosotebush (Larrea tridentata [DC.] Cov.) is the current dominant. A total of 3 334 black grama plants were found for an average density of 0.01 plants{\textperiodcentered}m-2. High spatial variation was found in the occurrence and basal area of black grama plants that was related to water availability rather than livestock grazing: most plants were found in or adjacent to an arroyo (67\%), at a northern aspect (47\%), and outside experimental exclosures established in 1930 (43\%). Largest average basal areas were found in the livestock exclosure, and in general, average basal area was not related with aspect or canopy microsite. These remnant plants can be used as propagule sources in restoration efforts, and information on microsite conditions for black grama survival can be used to improve restoration potential for similar sites.

}, keywords = {Bouteloua eriopoda, Flourensia cernua, Larrea tridentata, perennial grasslands, shrub invasion}, doi = {10.2111/05-202R1.1}, url = {/files/bibliography/06-028.pdf}, author = {Debra C. Peters and Mariotto, I. and Kris Havstad and Murray, L.M.} } @article {50495, title = {Snow: The Real Water Supply for the Rio Grande Basin}, journal = {New Mexico Journal of Science}, volume = {44}, year = {2006}, month = {August 2006}, pages = {99-118}, abstract = {The Rio Grande basin in Colorado, New Mexico, Texas, and Mexico is an important drainage in southwestern North America, vital for water consumption by a rapidly growing population, irrigated agriculture, economic development, preservation of endangered species, and energy generation. The most important source of water in the Rio Grande drainage results from snowmelt in the mountains of the upper basin. The gap between water supply and water demand is continually increasing as the population increases, and long term climate change further will affect the amount and timing of streamflow. The criticality of these problems will continue unabated through the 21st Century. Planning to cope with these water management problems needs to move now from relying on projections derived from current storage in reservoirs to additionally incorporating new technologies for measurements and hydrological modeling to allow the development of likely scenarios in both the short and long term. Models that can accept and integrate all types of measurements need to be utilized. Such models exist and are ready to be used operationally. Examples are given of both daily flow forecasts for an entire snowmelt season in the basin as well as predictions of future changes in streamflow to be expected under conditions of climate change. These types of data are vital in deciding among various future options which include the determination of the cost of water, controls on industrial and domestic development, new water distribution and storage systems, and the implementation of water conservation measures.}, keywords = {Rio Grande, southwestern North America, water supply}, url = {/files/bibliography/06-035.pdf}, author = {A. Rango} } @proceedings {50506, title = {Shrub-grass transitions and multiscale temporal variation in water availability}, year = {2006}, note = {ProCite field[28]: November 1, 2004ProCite field[29]: May 13, 2006}, month = {2006}, abstract = {Desert regions in the southwestern United States and northern Mexico exhibit a high degree of temporal variability in water availability with important consequences for transitions between grasslands and shrublands. This temporal variability is a result of: shifting climate regimes over centuries and decades, interannual variation in weather patterns, seasonal differences in the nature of winter and summer precipitation, within-season variability in precipitation frequency and magnitude, and feedbacks between vegetation and soil water.}, keywords = {multiscale, shrub-grass transitions, temporal variation, water availability}, author = {K. A. Snyder and S. Tartowski} } @conference {50511, title = {Sheep and goat grazing as a tool to mange encroachment of one-seed juniper (Juniperus monosperma Engelm. Sarg.)}, booktitle = {III Simposium Internacional de Pastizales}, year = {2006}, month = {August 9-11, 200}, pages = {13}, address = {Chihuahua, Mexico}, abstract = {The efficacy of using prescribed grazing by sheep and goats to suppress one-seed juniper re-invasion could be improved by providing adequate nutrients to help animals detoxify plant terpenes. We analyzed the terpenoid chemistry of one-seed juniper leaves and conducted feeding trials with 12 Ramboullet ewes and 12 Boer-Spanish nannies to determine if juniper intake (JI) varied seasonally (summer, fall or winter) or was affected by the amount and kind of crude protein (CP) available to detoxify terpenes. Diets were a sudangrass (Sorghum sudanensis) hay with either no protein added (Control diet: 5\% CP), or with soybean meal (degradable CP: DCP; 12.5\% CP) or fishmeal (by-pass CP: BPCP; 12.5\% CP). Juniper trials were conducted for 10 days in each season and consisted of a 30 min feeding bout on juniper branches (175g) attached to wooden stands (0.8 m height). Juniper leaves contained 51 terpenoids, 14 represented 95 \% of the total terpenoid amount, and {\'a}-pinene was the most abundant terpene (65\%). Juniper intake was greater for goats (0.54g kgBW-1) than Sheep (0.23g kgBW-1), and was higher for animals receiving the DCP (0.5g kgBW-1) and BPCP (0.41g kgBW-1) supplements than for control animals (0.25g kgBW-1). JI also varied among seasons (winter: 0.54g kgBW-1; summer: 0.38g kgBW-1; fall: 0.23g kgBW-1). Sheep and, especially, goats could be used in prescribed grazing programs to suppress juniper re-invasion. Greater suppression could be expected from goats browsing during winter, provided that protein levels are sufficient to allow them to detoxify terpenes efficiently.}, keywords = {goat, sheep, uniper}, author = {S. A. Utsumi and Andr{\'e}s F. Cibils and Richard E. Estell and S. Soto-Navarro} } @booklet {50533, title = {State and Transition Models 101: A Fresh Look at Vegetation Change}, howpublished = {Quivira Coalition Newsletter}, volume = {7}, number = {3}, year = {2005}, month = {August 3, 2005}, pages = {6-11}, abstract = {State-and-transition models are part of a new framework for evaluating the condition of rangelands, anticipating vegetation change, and planning land management. Government agencies, scientists, non-governmental organizations, and ranchers are involved in developing this framework. Why should you care? First, a clear understanding of vegetation change is critical. It lies at the center of the conflict (and cooperation) with which many of us are involved. It affects our bottom line, our interactions with others, and our ways of life. If you have ever wondered why vegetation has changed the way it has, what it used to look like, or what it could look like in the future, then you could probably use a state-and-transition model (hereafter, STM). Second. it is important to realize that both new scientific and policy developments will be connected to the concepts underlying STMs. Even an Undersecretary of the Interior Department and the director of the Bureau of Land Management (BLM) have publicly advocated the uses of STMs. The Nature Conservancy is also using STMs to prioritize conservation efforts. Alongside rangeland health, STM concepts will be part of the common language of natural resource management for years to come.}, keywords = {management, rangelands, state-and-transition, vegetation change}, url = {/files/bibliography/06-005.pdf}, author = {Brandon T Bestelmeyer and Joel R. Brown} } @article {50556, title = {Selected Essays on Science, Rangelands, and Roles of the Society for Range Management}, journal = {Rangelands}, volume = {27}, number = {6}, year = {2005}, month = {December 27, 200}, pages = {24-28}, abstract = {We are members of a field profession. As a scientist, I am also a member of a profession based on the written word. Often, unfortunately, in writing about this field, our chosen words often reflect the perpetual nature of the environment; dry, dusty, and typically sparse. Maybe it is part of the nature of objective scientific writing. The following collection of nine short essays has been written over recent years as an alternative to this more xeric verbage. Mostly, these have been written to be buried on the 3rd page of an obscure SRM section newsletter. A few have appeared in the SRM Member Resource News. It is my impression that these essays have been read by two people - and I, and another person who thinks I am of questionable intellect and can\&$\#$39;t wait to read my latest rambling as further proof of his conviction, and who then shares his reasoning with me. I have assembled these into a single collection here to offer an array of viewpoints for readers of Rangelands. These viewpoints range form perspectives on the sufficiency of our science to cultural statements expressed within a dairy parlor in China. The central thread is probably best summed as a passion for the profession occasionally tempered by a sense of humor for my minor role in that profession. http://www.srmjournals.org/archive/1551-501X/27/6/pdf/i1551-501X-27-6-24.pdf}, keywords = {management, range, range management, rangelands, science, viewpoints}, url = {/files/bibliography/05-018.pdf}, author = {Kris Havstad} } @article {50565, title = {Simulation of Vegetation Recovery from Military Disturbances on Fort Bliss}, number = {ERDC/CERL TR-05-39}, year = {2005}, month = {November 2005}, pages = {79}, publisher = {U.S. Corps of Engineers}, address = {Washington, DC}, abstract = {

This work covers two years of research by the USDA ARS, Jornada Experimental Range and the US Army ERCD/CERL. The overall goal of the project was to enhance the vegetation simulation modeling capabilities of Fort Bliss, Texas for evaluating the effects of military disturbances on aridland vegetation. The aim of this work was to mechanistically predict shifts from one community type to another by determining primary linkages between community types.

}, keywords = {Fort Bliss, military, recovery, simulation}, url = {/files/bibliography/06-016.pdf}, author = {Hochstrasser, T. and Debra C. Peters and J.S. Fehmi}, editor = {U.S. Corps of Engineers, Engineer Research and Development Center/Construction Engineering Research Laboratory} } @conference {50580, title = {Soil Geomorphic Change During Desertification}, booktitle = {Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meetings}, year = {2005}, month = {November 6-10, 2}, pages = {200-5}, address = {Salt Lake City, UT}, abstract = {The objective of this paper is to illustrate the concept of the soil-geomorphic template and its relationship to biotic change. Desertification, as an example of biotic change toward a degraded state, is a common phenomenon in many arid and semiarid regions of the world. Such biotic change is typically accompanied by and linked to geomorphic change. Geomorphic factors that are involved in biotic change are soil, topography, and soil parent material, which together form the soil-geomorphic template. Soil is involved because it is the substrate that provides water, nutrients, anchorage for roots, and habitat for burrowing animals. Topography is involved by its influence on microclimate via elevation, lateral redistribution of water, and slope aspect. Soil parent material is involved by its contribution to the nutrient supply. Numerous linkages and feedback-loops occur between the soil-geomorphic template, microclimate, vegetation, and animals. A perturbation in any of these factors can steer an ecosystem from one state to another. Some soil-geomorphic templates are more prone to change than others. For example, landscapes with sandy soils are more vulnerable to desertification than landscapes with fine-textured soils that receive run-in water and, therefore, require distinct management practices. Desertification involving simultaneous changes in biotic and geomorphic states provides a good example of how biological and geological systems are coupled and co-evolve.}, keywords = {desertification, geomorphic, soil}, author = {Curtis H. Monger and Brandon T Bestelmeyer} } @proceedings {50586, title = {Soil microorganisms and their importance in plant establishment and growth}, year = {2005}, month = {April 20-23, 200}, address = {Zacatecas, Mexico}, abstract = {Shrubs and grasses of the Chihuahuan Desert are more extensively colonized by atypical dark septate endophytes (DSE) than by common mycorrhizal fungi. DSE fungi are identified as stained or dark hyphae and microesclorotia in the root cortex by utilizing traditional trypan blue staining. Staining with Sudan IV, DSE fungi reveals lipid bodies attached to fungal structures indicating a higher incidence of fungal colonization that than previously observed. These fungi are intrinsically integrated with all the cells of the native and regenerated BOER plants. The transfer of fungi from BOER or SPCR calluses to nonhost plants indicated remarkable changes in root morphology and shoots biomass, chlorophyll content, and fruit and seed production. This study shows that plant-associated microbes can influence plant health and promote establishment and growth in different ecosystems.}, keywords = {Mycorrhizal fungi, plant establishment, plant growth, soil microorganisms}, author = {P. Osuna-Avila and J.R. Barrow} } @article {50616, title = {Soil change, soil survey, and natural resources decision making: A blueprint for action}, journal = {Soil Science Society of America Journal}, volume = {69}, year = {2005}, note = {Response to Issue (PDF 05-016) ARIS $\#$ 190338}, month = {May 6, 2005}, pages = {738-747}, abstract = {

Land managers and policymakers need information about soil change caused by anthropogenic and non-anthropogenic factors to predict the effects of management on soil function, compare alternatives, and make decisions. Current knowledge of how soils change is not well synthesized and existing soil surveys include only limited information on the dynamic nature of soils. Providing information about causes and attributes of soil change and the effects of soil change on soil function over the human time scale (centuries, decades, or less) should be a primary objective of 21st century soil survey. Soil change is temporal variation in soil across various time scales at a specific location. Attributes of change include state variables (dynamic soil properties), reversibility, drivers, trends, rates, and pathways and functional interpretations include resistance, resilience, and early warning indicators. Iterative elements of the blueprint for action described in this article are: (i) identify user needs; (ii) conduct interdisciplinary research and long-term studies; (iii) develop an organizing framework that relates data, processes, and soil function; (iv) select and prioritize soil change data and information requirements; (v) develop procedures for data collection and interpretation; and (vi) design an integrated soil-ecosystem-management information system. Selection of dynamic soil properties, soil change attributes, and functional interpretations to be included in future soil surveys should be based on analyses comparing the benefits of meeting user needs to the costs of data acquisition and delivery. Implementation of the blueprint requires increased collaboration among National Cooperative Soil Survey partners and other research disciplines.

}, keywords = {decision making, natural resources, soil change, soil survey}, url = {/files/bibliography/05-015.pdf}, author = {A.J. Tugel and Jeffrey E. Herrick and Joel R. Brown and Mausbach, M.J. and Puckett, W. and K. Hipple} } @inbook {50628, title = {A Staining Method for Systemic Endophytic Fungi in Plants}, booktitle = {Emerging Concepts in Plant Health Management}, volume = {Chapter 5}, year = {2004}, note = {Publisher is saving book chapters on CD-ROM; each author will receive a copy. December 2, 2003.}, month = {2004}, pages = {61-67}, publisher = {Research Signpost}, organization = {Research Signpost}, address = {Kerala, India}, abstract = {Native desert plants are extensively colonized by dark septate fungal endophytes (DSE). These are characterized by stained or pigmented hyphae and microsclerotia growing inter- and intra-cellularly within the root cortex. A dual-staining method was developed using trypan blue that targets fungal chitin and sudan IV that targets internal fungal lipid bodies. Roots and leaves of dominant grasses and shrubs of arid southwestern rangeland were dual-stained to determine the nature and extent of colonization by DSE fungi. Fungal structures ranged from lipid bearing protoplasts, hyaline, stained and melanized hyphae and microsclerotia. They inhabit the apoplastic spaces of roots and shoots. Predominant fungal structures are protoplasts in physiologically active tissues that are identified with stained, associated lipid bodies. This method shows colonization by DSE fungi is more extensive than was previouisly throught.}, url = {/files/bibliography/04-079.pdf}, author = {J.R. Barrow and Aaltonen, R.E.} } @conference {50634, title = {Scales of pattern and process in the management of the Chihuahuan Desert biodiversity}, booktitle = {11th Annual Conference, The Wildlife Society}, year = {2004}, month = {September 18-22,}, address = {Calgary, Alberta, Canada}, abstract = {In the Chihuahuan Desert concern about both the loss of biodiversity and economic productivity centers on the loss of grasslands and their transition to shrublands (i.e., desertification). Decades of research on this process have emphasized relatively fine scales. Although this was a necessary step, alone it is insufficient to explain instances and broader patterns of change. Furthermore, these processes have been only tenuously linked to biodiversity. We describe recent conceptual and empirical approaches to describing the process of transition based on cross-scale interactions between grass-shrub relationships and losses of grass in patches, between-patch connectivity and interactions with climate forcing functions, and landscape to regional-level feedbacks to climate. These processes create nonlinear changes in time and space such that different processes are important at particular times and spatial locations. This notion has important implications for monitoring and management. The variety of dynamics and patterns in vegetation and soils these processes create drive spatial and temporal variation in biodiversity. We discuss ongoing work to link ecosystem models to biodiversity data and to integrate management strategies based on rangeland and wildlife concerns.}, keywords = {approaches, biodiversity, Chihuahuan Desert, cross-scale}, author = {Brandon T Bestelmeyer and Debra C. Peters and Kris Havstad} } @conference {50632, title = {Soil-geomorphic basis of divergent landscape trajectories in the Chihuahuan Desert}, booktitle = {89th Annual Meeting, Ecological Society of America}, year = {2004}, month = {August 1, 2004}, pages = {p. 45}, address = {Portland, OR}, abstract = {A major emphasis of rangeland ecology and management is to understand the factors that regulate rates of vegetation and soil change. Explanations of change have traditionally ignored subtle soil heterogeneity and emphasized single processes. We sought to employ a multiscale, multifactor framework to interpret variability in rates of vegetation change occurring within a Chihuahuan Desert grassland under similar management. We used a combination of ground-based measures and remote-sensed data from 1936 and 1996 to construct a scenario explaining different rates of grass loss in two adjacent grassland areas on a piedmont slope. The two areas now merge at sharp ecotone separating a high-grass, low-shrub cover state and a state with lowgrass, high-shrub, and high-bare ground cover. The basis for these divergent trajectories is related to differences in the spatial pattern of soil calcium carbonate content and argillic horizon development. Where high carbonate soils with weak argillic horizons are relatively continuous, single-crown and stoloniferous grasses dominate at the expense of a rhizomatous grass. Grazing appears to have contributed to higher connectivity of bare ground where single-crown grasses predominated, leading to increased susceptibility to erosion, lower soil aggregate stability, lower rainfall infiltration, and soil truncation leading to accelerated rates of grass and shrub mortality. Under these conditions, grass and shrub cover are positively correlated at fine scales even when they are negatively correlated at a broad scale. Eroded soil accumulates on the highgrass side of the ecotone, contributing to ecotone contrast. This example illustrates the need for multiscale perspectives in explaining ecosystem resistance and resilience.}, keywords = {Chihuahuan Desert, ecology, management, rangeland, vegetation and soil change}, author = {Brandon T Bestelmeyer and J.P. Ward and Jeffrey E. Herrick and A.J. Tugel} } @article {50641, title = {Scale dependence in the species-richness-productivity relationship: the role of species turnover}, journal = {Ecology}, volume = {85}, number = {10}, year = {2004}, note = {//NMSU,USDA//LTER IV//Entered 11/14/2006.}, month = {2004}, pages = {2701-2708}, abstract = {

Recent research in aquatic systems suggests that productivity{\textendash}richness relationships change with spatial scale and that species turnover (i.e., spatial and temporal variation in species composition) plays an important role in generating this scale dependence. The generality of such scale dependence and the effects of variation in temporal scale remain unknown. We examined the extent to which the richness{\textendash}productivity relationship in terrestrial plant communities depends on spatial or temporal scale and evaluated how spatial and temporal turnover (i.e., species turnover in space and time) generates scale dependence in these relationships using data from two Long-Term Ecological Research (LTER) sites (Jornada and Konza). We found a weak hump-shaped relationship (Jornada) and no relationship (Konza) between richness and productivity at the smallest focal scale (1 m2 at Jornada and 50 m2 at Konza) at each site, but strong hump-shaped relationships at the largest focal scale (49 m2 at Jornada and 200 m2 at Konza) for each site. Relationships between spatial turnover and productivity at each site mirrored the productivity{\textendash}richness relationships that emerged at the larger spatial scale (i.e., a significant hump-shaped pattern). In contrast, temporal turnover was unrelated to productivity, and hence increasing temporal scale did not appreciably change the form of the productivity{\textendash}richness relationship. Our study suggests that the way in which productivity{\textendash}richness relationships change with spatial or temporal scale depends on the form and strength of the underlying relationship between species turnover and productivity. Moreover, we contend that a dominant effect of increasing productivity is the generation of dissimilarity in species composition among localities that comprise a region, rather than increasing the number of species that occur within local communities. Thus, understanding the mechanisms that cause species turnover to vary with productivity is critical to understanding scale dependence in richness{\textendash}productivity relationships.

}, keywords = {article, biodiversity, environmental heterogeneity, grasslands, journal, LTER, productivity, scale, species composition, species richness, species turnover, stability, terrestrial plants}, doi = {10.1890/03-0561}, url = {files/bibliography/JRN00418.pdf}, author = {Chalcraft, David R. and John W. Williams and M. D. Smith and Michael R. Willig} } @article {50656, title = {Sand flux in the northern Chihuahuan desert, New Mexico, USA, and the influence of mesquite-dominated landscapes}, journal = {Journal of Geophysical Research}, volume = {109}, number = {F04003, doi:10.J029/2003JF000031}, year = {2004}, month = {2004}, abstract = {

Measurements of sand flux over areas with different vegetation in the Chihuahuan desert show that mean, height-integrated, horizontal flux values for mesquite-dominated sites were higher than those for other kinds of vegetation. Sand transport over mesquite areas displayed seasonal variability for most years. This seasonal variability roughly followed the variability of strong winds. Sand transport rates for collectors within a short distance downwind of mesquite bushes were small compared to those for collectors at the end of streets (elongated patches of bare soil) aligned with wind direction. The increased rate of sand transport (wind erosion) associated with mesquite is important because mesquite-dominated areas are increasing in the northern Chihuahuan desert and are therefore responsible for increasing land degradation (desertification).

}, keywords = {Chihuahuan Desert, desert vegetation, dust emissions, journal article, mesquite, sand flux, sand transport}, doi = {10.1029/2003JF000031}, url = {/files/bibliography/04-010.pdf}, author = {D. E. Gillette and Pitchford, A.M.} } @conference {50660, title = {Short-term rangeland monitoring in support of collaborative management of the Valles Caldera National Preserve}, booktitle = {57th Annual Meeting, Society for Range Management}, year = {2004}, month = {January 25, 2004}, pages = {114}, address = {Salt Lake City, UT}, abstract = {The Valles Caldera National Preserve (VCNP) was established in July 2000 by the US Congress in order to {\textquotedblleft}protect and preserve{\textquotedblright} the resources encompassed within its boundaries. A Board of Trustees was appointed to administer this land and facilitate cooperative management of this 90,000-acre preserve in northern New Mexico. This management is based on a set of ten principles that deal with protecting resources, advancing science, recognizing cultural interests, providing quality experiences to those who visit the preserve, and maintaining the ecological balance of the landscape. Additionally, the VCNP provides an affordable forage base for local producers. The USDA/ARS Jornada Experimental Range was invited to participate in developing a monitoring program for the approximately 30,000 acres of grazeable rangeland within the VCNP. In 2001-2002, 41 monitoring points were established for both short- and long-term monitoring objectives. The points were set up within four ecological sites: riparian, mountain meadow, mountain valley, and grazeable woodlands. The methods of monitoring were developed with several goals in mind: to be quickly done in the field and quickly processed, to be easily taught to the public, to be repeatable and to be tied to long-term monitoring. Using a paired-caged-plot method, data on production, utilization and standing biomass were collected for the June through September grazing seasons in 2002 and 2003 and will continue into the future. Monitoring data will be used to manage these resources and, specifically, to manage grazing by livestock and elk.}, author = {Amy L. Gonzalez and Connie J. Maxwell and B. Nolen} } @conference {50668, title = {Soil carbon response to rangeland vegetation change: Implications for management and monitoring}, booktitle = {Soil Science Society of America Annual Meeting}, year = {2004}, address = {Seattle, WA}, abstract = {We measured soil carbon to a depth of 50 cm across a range of Chihuahuan Desert soils and plant communities in order to, (1) determine the effects of rangeland vegetation change, and (2) develop cost-effective sampling requirements for quantifying net changes in soil carbon sequestration. We measured soil carbon at 18 points in each of three one-ha plots in a relatively undegraded black grama grassland community and in a mesquite shrubland that was a black grama grassland approximately 100 y BP. Carbon and bulk density determinations were completed at 0-1, 1-5, 5-18 and 18-50 cm depths using the core method. Soil carbon in the mesquite duneland plots was generally higher than in the black grama grassland. However, the potential benefits of short-term carbon sequestration must be balanced against the long-term costs of increased soil erosion and the lower value of the mesquite shrublands for forage production and other land uses. Soil carbon variability was greater within plots than among plots. Much of this variability was attributed to plant-interspace differences, suggesting that a stratified sampling protocol may reduce sampling costs.}, keywords = {cost-effective, rangeland vegetation change, sampling protocol, sampling requirements, soil carbon response}, author = {Jeffrey E. Herrick and Curtis H. Monger and Kramer, R. and A.J. Tugel and M.D. Remmenga and Joel R. Brown} } @proceedings {50665, title = {Soil survey enhancements for natural resource management: Case studies from the southwestern U.S.}, year = {2004}, note = {CDROM: USDA-NRCS}, month = {June 13-18, 2004}, pages = {CDROM}, address = {Jackson, WY}, abstract = {This paper illustrates how both new types of data and the reinterpretation of existing data can be used to improve the quality and value of soil survey interpretations for natural resource management. New data on soil resistance and resilience to different types of disturbance can be used to select dynamic soil properties for inclusion in future soil surveys. Other factors, including data cost and quality, must be considered in the selection of dynamic soil properties. In the short term, we discuss an example of how GIS analysis tools can be used together with spatial slope and elevation information to produce more detailed thematic maps from existing Order 3 soil surveys. We conclude that (1) future soil survey enhancements depend on the development of soil and ecological, site-specific information on dynamic soil properties, (2) soil interpretations based on integration of GIS and process-based conceptual models increase the value of existing soil survey data, and (3) application of these conclusions will be facilitated by displaying soil as a continuum across the landscape.}, keywords = {dynamic soil properties, GIS integration, natural resource management, soil survey, Southwest}, url = {/files/bibliography/04-050ABS.pdf}, author = {Jeffrey E. Herrick and Merkler, D. and Biggam, P. and A.J. Tugel} } @article {50670, title = {Subdominant species distribution in microsites around two lifeforms at a desert grassland-shrubland transition zone}, journal = {Journal of Vegetation Science}, volume = {15}, number = {5}, year = {2004}, month = {October 1, 2004}, pages = {615-622}, abstract = {In many vegetation types, plant species diversity is dependent on the abundance of subdominant plants in microsites around dominant plants. Our objective was to compare subdominant abundance in microsites around dominant grasses and shrubs in the same landscape context. We investigated the distribution of subdominant plants in three microsites (canopy, canopy edge and interspace) around individual shrubs (creosotebush, Larrea tridentata) and grasses (black grama, Bouteloua eriopoda) at a grassland-shrubland transition zone that has been encroached by shrubs within the past 50-100 years. Subdominant plants were sampled using plots of variable size according to microsite type and dominant plant size. Contrary to our expectations, subdominant species abundance was higher in microsites around creosote shrubs than in microsites around black grama. Furthermore, differences in species abundance and composition were higher among microsites around grasses than among microsites around shrubs. The distribution of subdominants was mostly explained by their phenological characteristics, which indicates the importance of temporal variation in resources to their persistence. This detailed study of coexistence patterns around dominants revealed ecological contrasts between two dominant lifeforms, but other factors (such as disturbances) have to be taken into consideration to evaluate landscape-scale diversity.}, keywords = {annual, Bouteloua eriopoda, dominant plant, ECOTONE, functional group, Larrea tridentata, scale, shrub invasion, spatial heterogeneity}, url = {/files/bibliography/04-006.pdf}, author = {Hochstrasser, T. and Debra C. Peters} } @conference {50686, title = {Spatial variation in remnant black grama plants in a creosote-dominated bajada}, booktitle = {Sixth Symposium on the Natural Resources of the Chihuahuan Desert Region}, year = {2004}, month = {October 15, 2004}, pages = {33}, address = {Alpine, TX}, abstract = {Much of the Chihuahuan Desert has converted from perennial grasslands to shrub-dominated systems over the past century. Although shrub-dominated systems appear homogeneous with very few grass plants, observations suggest that perennial grasses can occur within these areas. Our overall objective was to quantify the presence and abundance of the perennial grass, Bouteloua eriopoda (black grama), in creosotebush-dominated bajadas at the Jornada Experimental Range in southern New Mexico. In 2002 and 2003, we obtained the geo-referenced location, aspect, two diameters, and location within shrub canopies for all black grama plants in a 530 m x 550 m area located inside and outside an exclosure constructed in the 1930s. Spatial data layers in a GIS were used as explanatory variables in our analyses. Our results show that a total of 3335 black grama plants were found with an average density of 0.01 plants/m2. Most black grama plants were found inside and adjacent to arroyos (66.7\%), at a northern aspect (47\%), and outside the exclosure (62\%). Black grama most likely dominated this site in 1858, although by 1915 the area was dominated by tarbush, and by 1998 it was dominated by creosote. Thus, the source population for these current black grama plants is most likely remnant plants that historically dominated the area, although seed inputs from nearby mountainous pastures are also possible. Our results showing the location of black grama plants within creosote-dominated systems can be used for remediation of these areas.}, keywords = {black grama, Bouteloua eriopoda, Chihuahuan Desert, creosote-dominated bajada, remediation, spatial variation}, author = {Mariotto, I. and Debra C. Peters and Kris Havstad and L. W. Murray} } @mastersthesis {50691, title = {Scaling approaches to the modelling of water, sediment and nutrient fluxes within semi-arid landscapes, Jornada Basin, New Mexico}, year = {2004}, note = {//NMSU, USDA//LTER IV//entered 02/29/2008//updated 03/04/2008, 04/14/2008, 07/22/2008ProCite field[12]: In File (02/29/2008)}, month = {2004}, pages = {271}, school = {King{\textquoteright}s College London, University of London}, address = {Berlin}, abstract = {Overland flow generated by high-intensity rainstorms has been suggested as having an important role in desertification, resulting in a significant vegetation change from productive grassland to desert shrubland in the southwestern part of the United States. For the quantification of overland flow and associated nutrient and sediment fluxes, there are significant scale issues involved that require resolution. To address these issues, a fieldwork-integrated modeling approach was employed to enable the quantification of water, sediment and nutrient fluxes within and between shrubland and grassland associations in a semi-arid ecosystem, Jornada Basin in the Chihuahuan Desert, New Mexico. This thesis is the evaluation of scaling approaches to the numerical modeling of these fluxes combined with the appropriate application of scaling tools for model parameterization. Special emphasis is placed on the investigation of parameter and process scaling and the applicability of scaling tools to interpolate and extrapolate field data, disaggregate remotely sensed data and aggregate model parameters. Extensive field studies were carried out to acquire detailed understanding of the spatial distribution of hydrological, soil- and nutrient-related model parameters within black gramma grassland and creosote, tarbush and mesquite shrublands. The statistical and geostatistical analysis of the field data resulted in the development of scaling techniques that enable the spatially realistic reproduction of the small-scale variability and connectivity features of model input parameters. Spatially distributed, process-orientated models with a 2-m resolution were employed to enable an adequate representation of model input parameters and an appropriate reproduction of overland flow characteristics and sediment- and nutrient-transport processes. Based on these results, the models were upscaled to a resolution of 10-m under specific evaluation of process and parameter scaling issues. The upscaled model versions were then employed for the flex quantification within and percentage change in fluxes between shrubland and grassland associations. The modeling studies provided important insights into stability of grassland-shrubland boundaries as a function of nutrient depletion and water-resource enrichment for the grassland by the action of overland flow. It was hypothesized that external forces such as overgrazing or climatic variations might potentially disturb the stability, which consequently leads to the invasion of shrubs into the grassland. The modeling results suggest that landscape linkages through the redistribution of water and soil resources across vegetation-transitions zones at the landscape scale play a significant role in the certification processes.}, keywords = {dissertation, hydrology, creosotebush, hydrology, ecosystem dynamics, hydrology, grassland, hydrology, model, hydrology, nutrient fluxes, hydrology, nutrient transport, hydrology, overland flow, hydrology, overland-flow model, hydrology, processes, hydrology, remote sensing, hydrology, sediment fluxes, hydrology, sediment transport, hydrology, sheet flow, hydrology, shrubland, hydrology, stock tanks, hydrology, surface runoff, model, hydrology, thesis}, author = {Eva N. M{\"u}ller} } @article {50707, title = {Selection of models of invasive species dynamics}, journal = {Weed Technology}, volume = {18}, year = {2004}, month = {August 1, 2004}, pages = {1236-1239}, abstract = {

Mathematical and process-based simulation models are powerful tools for synthesizing information about invasive species. However, there are a number of different types of models, ranging from simple to complex that can be selected for any given application. In this article, a model classification framework of three types of models is applied to studies of invasive species that allows the objective selection of a model type on the basis of its ability to capture key processes and dynamics, yet minimize the errors in prediction. Model selection is illustrated using a series of increasingly complex models.

}, keywords = {biotic, dynamics, environmental, invasive, landscape, Nonspatial models, spatially explicit models, spatially implicit models.}, doi = {10.1614/0890-037X(2004)018[1236:SOMOIS]2.0.CO;2}, url = {files/bibliography/JRN00420.pdf}, author = {Debra C. Peters} } @conference {50706, title = {Spatial nonlinearities and cascading effects across landscapes in the Earth system}, booktitle = {LAND Open Science Conference}, year = {2004}, month = {December 2, 2004}, pages = {50}, address = {Morelia, Mexico}, abstract = {Our objective was to develop and apply a conceptual framework to examine the importance and generality of spatial nonlinearities in the dynamics of the Earth system. Atmosphere-biosphere interactions are increasingly recognized as important to local ecosystem dynamics as well as to the global carbon cycle. However, the multi-scale nature of these interactions and their feedbacks are less well-known and poorly understood. This lack of understanding leads to ecological {\textquoteright}surprises{\textquoteright} associated with nonlinear ecosystem responses to broad-scale forcing functions and feedbacks to the atmosphere. Our lack of understanding about these nonlinear dynamics cascading spatially across landscapes (i.e., spatial nonlinearities) severely limits our ability to identify the conditions leading to catastrophic events, as well as the impacts of these events on local and regional economies, conservation of species, ecosystem services, and balances in atmospheric gases. We examine these spatial nonlinearities in the dynamics of the Earth system in the context of interactions and feedbacks between atmospheric processes and ecosystem structure and dynamics across a range of spatial and temporal scales. We surmise that changes in spatial pattern of ecosystems over time, especially at the landscape scale, due to local ecological processes mediate the influence of atmospheric processes operating at broader scales. Rapid shifts in rates of atmospheric processes across values of spatial metrics create thresholds in time and feedbacks to spatial structure of the landscape with subsequent feedbacks to the atmosphere. Thus, small changes in spatial pattern can determine if a forcing function is amplified or attenuated across a landscape. It is only by accounting for these complex, multi-scale feedbacks between local ecological processes, landscape structure, and the atmosphere that can we begin to understand extreme events and to reduce the probability that we will be surprised. We first develop a theoretical framework to describe these complex interactions that builds on ideas from a number of disciplines, in particular, ecology and atmospheric sciences; then, we present several key examples from different systems to illustrate emerging patterns and concepts, as well as insights to improving management.}, author = {Debra C. Peters} } @article {50702, title = {Strategies for ecological extrapolation}, journal = {Oikos}, volume = {106}, number = {3}, year = {2004}, month = {September 1, 200}, pages = {627-636}, abstract = {

Extrapolation of information collected at fine scales to broader scales is an increasingly important issue in ecology as the recognition of spatial connections within and among different levels of organization expands. In addition, our ability to represent complex behavior in ecological systems has improved with readily available instrumentation and software that allows detailed sampling and analysis and the ease with which geospatial data can be used to support large spatial simulation models or extensive data-based inventories and assessments. However, there is a tradeoff between simple approaches having errors associated with excluding processes and more complex approaches that are plagued by high uncertainty due to increased estimation and measurement error. In this paper, we develop a synthetic, problem-solving framework for extrapolating information from fine to broad scales that is applicable to a wide range of ecological problems. The framework includes three classes of approaches that differ in their complexity and sources of error: nonspatial, spatially implicit, and spatially explicit. We consider a range of ecological issues requiring complex approaches (i.e., nonlinear processes, thresholds, positive feedbacks, neighborhood processes) and identify options for dealing with these issues. Our operational framework of model selection serves as a practical and objective approach to the problem of ecological prediction across a range of spatial and temporal scales. Thus, this framework should be of interest to all ecologists concerned with the problem of prediction.

}, keywords = {complex, complex behaviors, define and control prediction, ecological extrapolation, exclude key processes, increased estimation, ingenerating accurate, measurable reduction, measure, measurement error, models, prediction bias, prediction errors, propagation, software, spatial extrapolation ofinformation are an important issue in ecology. Althoughimprovements in instrumentation, trade-offsimpedes, unknown prediction}, doi = {10.1111/j.0030-1299.2004.12869.x}, url = {/files/bibliography/04-003.pdf}, author = {Debra C. Peters and D.L. Urban and Gardner, R.H. and David D. Breshears and Jeffrey E. Herrick} } @article {50721, title = {Soil disturbance by soil animals on a topoclimatic gradient}, journal = {European Journal of Soil Biology}, volume = {40}, number = {2}, year = {2004}, month = {August 6, 2004}, pages = {73-76}, abstract = {

We measured the area and volume of soil disturbed by various groups of animals at three sites on a topoclimatic gradient in the Judean Desert, Israel. Both the area and volume of soil disturbed by animals correlated with the cumulative precipitation of the winter rain season. Rodent activity accounted for most of the soil disturbance at all sites except for June 2001, when the volume of soil transported to the surface by ants in the construction of nest chambers accounted for most of the soil volume moved at the intermediate rainfall site. The aggregate stability of soil ejected from animal excavations was significantly lower than that of undisturbed soil during and immediately following the winter rain season, but not during the following dry seasons. The quantities of soil moved by ants in the Judean Desert were comparable to quantities moved by ants in the Chihuahuan Desert of North America.

}, keywords = {disturbance, gradient, measure, soil, topoclimatic, volume}, doi = {10.1016/j.ejsobi.2004.07.001}, url = {/files/bibliography/04-078.pdf}, author = {Yosef Steinberger and Pen-Mouratov, S. and Walter G. Whitford} } @conference {50726, title = {Sampling dynamic soil properties for soil surveys and state-and-transition models: Big Bend National Park}, booktitle = {Western Regional Soil Survey and Land Resource Workshop}, year = {2004}, month = {February 12-13, }, address = {College Station, TX}, abstract = {Soil change information is needed by today{\textquoteright}s decision makers for a variety of management goals, including short and long-term productivity, economics, sustainability, and environmental quality. However, soil survey databases do not provide information about the historical or expected dynamics of soil properties that change in response to management and disturbances. Sampling methods for bulk density, salinity, pH, soil surface stability, canopy cover and canopy gap were tested during soil survey activities at Big Bend National Park. State-and-transition models for ecological sites were used to select sampling sites and provide a framework to illustrate relationships among data. Procedures and results will be presented. The soil survey map unit component can serve as the data carrier for soil information related to changes in function and hence, to states within an ecological site. Inclusion of state-dependent dynamic soil property values will enhance information on soil-vegetation dynamics within ecological site descriptions, add value to soil surveys, aid the interpretation of assessment and monitoring results, and increase our knowledge of soil change.}, keywords = {Big Bend National Park, soil properties, soil surveys, state-and-transition models}, author = {A.J. Tugel and Loomis, L. and S. Andrews and Dyess, J. and Jeffrey E. Herrick and G. Peacock and Biggam, P.} } @proceedings {50727, title = {Sampling dynamic soil properties for soil surveys: Lessons learned}, year = {2004}, note = {CDROM: USDA-NRCS}, month = {June 13-18, 2004}, pages = {CDROM}, address = {Jackson, WY}, abstract = {Today{\textquoteright}s land managers and policy makers need information about how soils change to compare alternatives and make decisions for economically and environmentally sound resource management. Soil-change information can be used to answer questions about current soil condition and make predictions of future conditions. However, soil surveys do not provide information about historical or expected dynamics of soil properties that change in response to management and disturbances. Data collection procedures tested for the Soil Survey of Big Bend National Park, TX, included: bulk density, salinity, pH, soil surface stability, infiltration, impact penetrometer, modified singleton-blade, organic and inorganic carbon, canopy cover and canopy gap. Soil surface stability, bulk density soil organic and inorganic carbon and electrical conductivity differed significantly among ecological states. However, differences for some properties were probably not functionally significant. State-and-transition models for ecological sites were used to select sampling sites and illustrate relationships among data. The experiences gained will be used to improve methods, sampling design, and field efficiency. Research needs were identified. State-dependent, dynamic soil property values will add value to soil surveys, enhance information on soil-vegetation dynamics within ecological site descriptions, and increase our knowledge of soil change.}, keywords = {bulk density, land management, resource management, soil properties, soil property dynamics, soil survey}, url = {/files/bibliography/04-049Proc.pdf}, author = {A.J. Tugel and Loomis, L. and S. Andrews and Dyess, J. and Jeffrey E. Herrick and G. Peacock and Biggam, P.} } @conference {50724, title = {Sampling near-surface dynamic soil properties for soil surveys, assessment and monitoring and state-and-transition models}, booktitle = {57th Annual Meeting, Society for Range Management}, year = {2004}, month = {January 25-30, 2}, pages = {367}, address = {Salt Lake City, UT}, abstract = {Interpreting function-based assessments and monitoring of rangelands requires information about the temporal dynamics of indicators. Reference values for indicators that reflect primary ecological processes can be used to evaluate changes in the soil{\textquoteright}s capacity to function. However, soil survey databases do not provide information about the historical or expected dynamics of soil properties in response to management and disturbances. Sampling methods for bulk density, salinity, pH, soil surface stability, canopy cover and canopy gap were tested during soil survey activities at Big Bend National Park. State and transition models for ecological sites were used to select sampling sites. Soil surface stability, bulk density and electrical conductivity differed significantly among ecological states. However, differences for bulk density and salinity were not functionally significant. The soil survey map unit component can serve as the data carrier for soil information related to changes in function and to states within an ecological site. Inclusion of state-dependent dynamic soil property values provides reference values that can be used to interpret assessments and evaluate monitoring trends. Soil survey enhancements for dynamic soil properties and soil function will benefit assessment and monitoring activities, enhance information on soil-vegetation dynamics within ecological site descriptions, add value to soil surveys, and increase our knowledge of soil change.}, author = {A.J. Tugel and S. Andrews and Loomis, L. and Jeffrey E. Herrick and G. Peacock and Biggam, P.} } @conference {50725, title = {Soil survey enhancements for assessment, monitoring, and restoration: Big Bend National Park case study}, booktitle = {Sixth Symposium on the Natural Resources of the Chihuahuan Desert Region}, year = {2004}, month = {October 15, 2004}, pages = {43}, address = {Alpine, Texas}, abstract = {Changes in near-surface dynamic soil properties should be considered when selecting locations for assessment, monitoring, and restoration. However, soil surveys do not currently provide information about the historical or expected dynamics of soil properties in response to management and disturbances. A preliminary study in the Chihuahuan Desert for selected, dynamic soil properties was conducted by the NRCS soil survey crew working at Big Bend National Park, Texas. The soil survey map, ecological site description, and state-and-transition model were used to select plots on the same ecological site. Soil and vegetation measurements included bulk density, salinity, pH, organic and inorganic carbon, soil surface stability, infiltration, canopy cover, and canopy gap. Comparisons were made among ecological states within an ecological site. Mean values for bulk density, salinity, organic carbon, soil surface stability, and the variance of soil organic carbon and salinity differed significantly among ecological states. However, differences in means for bulk density and inorganic carbon may not be functionally significant. The state-and transition-model was used to help explain relationships among data and the data were used to validate the model. Information about the spatial heterogeneity and temporal dynamics of near-surface soil properties should be added to soil surveys to provide data needed by land manager. Dynamic soil property data in conjunction with traditional soil survey information can be used to interpret results of assessments and monitoring, select restorable sites, and develop treatment alternatives.}, keywords = {assessment, Big Bend National Park, monitoring, near-surface soil, restoration, soil properties, soil survey}, author = {A.J. Tugel and Loomis, L. and Dyess, J. and Brandon T Bestelmeyer and Jeffrey E. Herrick and S. Andrews and G. Peacock and Biggam, P.} } @conference {50728, title = {Spatial heterogeneity of dynamic soil properties for management and restoration of desert landscapes}, booktitle = {89th Annual Meeting, Ecological Society of America}, year = {2004}, month = {August 1, 2004}, pages = {Abstract p. 513}, address = {Portland, OR}, abstract = {Restoration of rangelands requires information about the temporal dynamics of soil and vegetation. However, soil survey databases do not provide information about the historical or expected dynamics of soil properties in response to management and disturbances. Information about the temporal nature of soil and its heterogeneity at multiple scales requires new soil survey methods for gathering and reporting soil and vegetation dynamics. A preliminary study in the Chihuahuan Desert for the collection of dynamic soil properties was conducted by the NRCS soil survey crew at Big Bend National Park, Texas. The soil survey map, ecological site description and state-and-transition model were used to select plots. State-and-transition models were also used to illustrate relationships among data. Soil and vegetation measurements included bulk density, salinity, pH, carbon, soil surface stability, canopy cover and canopy gap. Soil surface stability, bulk density and electrical conductivity differed significantly among ecological states. However, differences for bulk density and salinity may not be functionally significant. Near-surface soil property information can provide additional information about the consequences of degradation as well as insight to the feasibility of restoration success.}, keywords = {desert landscapes, management, rangelands, restoration, soil, vegetation}, author = {A.J. Tugel and Loomis, L. and S. Andrews and Dyess, J. and Brandon T Bestelmeyer and Jeffrey E. Herrick and G. Peacock and Biggam, P.} } @conference {50732, title = {Spatial and temporal variation in desertification due to stressors at multiple scales}, booktitle = {LAND Open Science}, year = {2004}, month = {December 2, 2004}, pages = {32}, address = {Morelia, Mexico}, abstract = {Desertification, in particular, shrub invasion into former grasslands, is a worldwide and well-known phenomenon in arid and semiarid areas; however, detailed quantification of spatial and temporal variation in desertification is rare. A number of interacting factors have been implicated for desertification, including livestock grazing, drought, herbivory by small animals, reduction in fire frequency, and global climate change; but, the exact role of these factors remains unclear. Using the long-term datasets collected at the Jornada Experimental Range, New Mexico, USA, we examined spatial and temporal variation in shrub invasion and grass persistence and identified the factors resulting in the variations. The dependent variables, basal area and annual growth of perennial grasses, were measured in 105 1 x 1 m permanent chart quadrats set up between 1915-32 and monitored annually until 1979, and periodically since that time. The explanatory variables included factors at both the local and landscape scales. The local factors considered were soil texture, depth to the top of caliche layer, precipitation, and micro-topography; the landscape factors were elevation, pasture stocking rate, and distance to historic shrublands. Our results showed that not all grasslands disappeared after the severe drought of 1950s: upland grass species (black grama, mesa dropseed, and threeawns) survived in a few quadrats and playa grass species (tobosa and burrograss) recovered to near pre-drought level in many quadrats. Spatial and temporal variations in grass persistence were results of interactions between climatic and landscape factors: both local and landscape factors affected grass persistence, but factors related to grass persistence varied with species and time period during 1915-2001. Our results increase our understanding of desertification in the face of global change and provide important information for the prediction of land cover change in arid and semiarid areas in the future.}, author = {Jin Yao and Debra C. Peters and Gibbens, Robert P. and Kris Havstad and Jeffrey E. Herrick} } @article {50748, title = {Scavenging ant foraging behavior and variation in the scale of nutrient redistribution in semiarid grasslands}, journal = {Journal of Arid Environments}, volume = {53}, number = {3}, year = {2003}, month = {March 1, 2003}, pages = {373-386}, abstract = {The scavenging of arthropod carrion by ants is an important mechanism of nutrient redistribution in grasslands. But, the foraging activities of scavenging ants have been scarcely documented. We examine variation in overall ant foraging activity among grassland regions differing in species composition and how this creates differences in the distances that scavenged material is redistributed among three semiarid grassland ecosystems. In order to consider the effects of the ant community as a whole on the disposition of nutrient resources, we focused on the fate of baits that appeared under different environmental conditions. Specifically, we asked 1) which ant species are the dominant scavengers in each grassland, 2) what ant characteristics determine the distance that baits are removed to nests, and 3) how do these patterns come together to create differences among grassland ecosystems in the distance that scavenged resources are removed? Species at a site differed widely in the microclimatic conditions that they removed baits and in the average distances they were removed. Generally, species with large-bodied workers and thermophilic species removed baits the farthest. Overall, this resulted in a positive relationship between removal distance and vapor pressure deficit (VPD). Controlling for intersite variation in habitat types and VPD, mean removal distance across all ants increased from the shortgrass steppe to the Chihuahuan Desert grassland. We conclude that differences in the foraging ecology and body size of the dominant scavengers among these grasslands can create a seven-fold variation in the spatial scale of nutrient concentration by ants. These species are little-known when compared to the harvester ants emphasized in ecosystem studies.}, url = {/files/bibliography/03-005.pdf}, author = {Brandon T Bestelmeyer and J.A. Wiens} } @booklet {50770, title = {Supplement to the Desert Project Soil Monograph, Volume III}, howpublished = {Soil Survey Investigations Report No. 44}, year = {2003}, note = {//LOCAL,NMSU,USDA//NONE//}, month = {2003}, pages = {374 pp}, publisher = {USDA Natural Resources Conservation Service}, address = {National Soil Survey Center, Lincoln, NE}, abstract = {

Volume III of the Supplement to the Desert Project Soil Monograph is the third in a number of volumes about soils and landscapes in the Desert Project area. Volume III consists of two chapters. The first is an update of the Desert Project soil survey, along with many illustrations of its features. Because of the high significance of carbon in studies of global change, particular attention is paid to composition of the map units with respect to both organic and carbonate carbon. This information has been used in the second chapter on areal evaluation of organic and carbonate carbon. Recent advances in color technology and computer-generated maps have been used in sections involving both general and detailed soil maps, maps of morphological and physiographic features, and maps illustrating soil-geomorphic reconstruction. In addition, color photography has been used to illustrate the effects of increasing precipitation from the arid to the semiarid zone; the effects of moisture differences resulting from surface and subsurface concentrations of moisture; sites dated by radiocarbon ages of buried charcoal; other features of the semiarid zone; and soils of Holocene scarps in high-carbonate parent materials. Land survey notes, grazing records, aerial photographs, and present conditions indicate extensive dune formation and dramatic changes in vegetation from about 1885 to 1936. Repeat photography documents major vegetation changes in the last 20 to 80 years.

}, keywords = {book, books, chapter, chapters, Desert Project, geomorphology, Desert Project, soil, geomorphology, Desert Project, photography, aerial, photography, repeat, photography, time sequence, report, reports, soil characteristics, Desert Project, soil chemistry, Desert Project, soil formation, soil mapping, soil properties, Desert Project, soil survey, Desert Project, soil, argillic horizon, soil, aridisols, soil, boundaries, soil, calcareous, soil, calcic horizon, soil, calcite, soil, calcium carbonate horizon, soil, carbonate, soil, charcoal horizons, soil, chronosequence, soil, classification, soil, description, soil, Desert Project, soil, geomorphic relationships, soil, landscape, soil, map-unit boundaries, soil, Paleargid horizon, soil, paleosols, soil, petrocalcic horizon}, author = {L. H. Gile and R. J. eds. Ahrens}, editor = {S. P. Anderson} } @conference {50785, title = {Sustainable management of arid lands: Recovery time and threshold dynamics in desert grasslands and shrublands}, booktitle = {88th Annual Meeting, Ecological Society of America}, year = {2003}, month = {August 3-8, 2003}, pages = {151}, address = {Savannah, GA}, abstract = {For managed disturbances, such as military training activities or recreational use, a sustainable disturbance regime allows ecosystems to recover to predisturbance conditions between disturbance events. In arid environments, recovery from disturbance typically requires long time periods. Furthermore, disturbance may alter vegetation dynamics such that thresholds are crossed and a shift in dominance from grasses to shrubs is observed. Such a shift in dominance is considered irreversible under current climatic conditions because of positive feedback mechanisms between the biotic and abiotic environment. Disturbance management in arid lands depends on knowledge about recovery time and thresholds in system dynamics. The objective of this study was to investigate how recovery time and susceptibility to a change in dominance vary between vegetation types in southern New Mexico. We used an individual-based simulation model (ECOTONE) to simulate disturbances with different timing with respect to climate events, different sizes, and different intensities in desert grasslands and shrublands. Both vegetation types recovered easily from low intensity disturbances. Recovery time on large disturbance was determined by the seed dispersal distance of the dominant species. Disturbances with high intensity in grasslands caused a shift in dominance from grasses to shrubs. The probability of such a shift in dominance depended on the timing of the disturbance with regard to climatic events and soil type. These results correspond to observations on vegetation dynamics after disturbance in southern New Mexico. Using this model, we were able to refine disturbance management recommendations for desert grasslands and shrublands.}, author = {Hochstrasser, T. and Debra C. Peters and J.S. Fehmi} } @conference {50796, title = {Simulation modelling of soil inorganic carbon in arid environments}, booktitle = {88th Annual Meeting, Ecological Society of America}, year = {2003}, month = {August 3-8, 2003}, pages = {238}, address = {Savannah, GA}, abstract = {Pedogenic carbonate, or soil inorganic carbon, is an important constituent of subhumid-to-arid soils throughout the world. Although terrestrial carbon cycling science has placed more emphasis on organic carbon, arid and semiarid soils store approximately ten times more inorganic carbon than organic. It has been estimated that more than 8 x 1014 kg of C are sequestered globally in calcic and petrocalcic horizons of Aridisols and Mollisols. Our goal was to examine and test hypotheses regarding the relationship of calcium carbonate (CaCO3) in arid lands to atmospheric CO2 sequestration. The magnitude of soil inorganic carbon flux with the atmosphere is difficult to estimate at local, regional or global scales. We developed a conceptual model and an associated process-based model to simulate the rate of formation and vertical distribution of CaCO3 in soil horizons in the arid southwestern U.S. The model depicts short term processes of CaCO3 precipitation and dissolution that occur in periods of days to centuries to millennia. We use the model to illustrate the environmental and biotic conditions that control the CaCO3 source-to-sink relation. Initial findings show that pedogenic carbonate can serve not only as a sink, but also as a source for CO2. Our simulation modelling framework helps illustrate the historic and future conditions under which soil carbonates alternate between storing and releasing CO2 to the atmosphere.}, author = {K. A. Mitchell and Curtis H. Monger and Jeffrey E. Herrick and Debra C. Peters} } @article {50798, title = {Sensor development and radiometric correction for agricultural applications}, journal = {Photogrammetric Engineering and Remote Sensing}, volume = {69}, number = {6}, year = {2003}, month = {06/2003}, pages = {705-718}, abstract = {

This review addresses the challenges and progress in sensor development and radiometric correction for agricultural applications with particula emphasis on activities within the U.S. Department of Agriculture (USDA) Agricultural Research Service (ARS). Examples of sensor development include on-site development of sensors and platforms, participation in cooperative research and development agreements (CRADA) with commercial companies, and membership on NASA science teams. Examples of progress made in sensor radiometric correction suitable for agriculture are presented for both laboratory and field environments. The direction of future sensor development includes integrated sensors and systems, sens standardization, and new sensor technologies measuring fluorescence and soil electrical conductivity, and utilizing LIght Detection and Ranging (LIDAR), hyperspectral, and multiband thermal wavelengths. The upcomin challenges include definition of the core spectral regions for agricult and the sensor specifications for a dedicated, orbiting agricultural sensor, determination of an operational approach for reflectance and temperature retrieval, and enhanced communication between image provide research scientists and users. This review concludes with a number of avenues through which USDA could promote sensor development and radiometric correction for agricultural applications. These include developing a network of large permanent calibration targets at USDA ARS locations, investing in new technologies, pooling resources to support large scale field experiments, determining ARS-wide standards for sensor development, calibration and deployment, and funding interagency agreements to achieve common goals.

}, url = {/files/bibliography/03-047.pdf}, author = {S. Moran and Fitzgerald, G. and A. Rango and C. Walthall and Barnes, E. and Bausch, W. and Clarke, T. and Daughtry, C. and J. Everitt and D.E. Escobar and J. Hatfield and Kris Havstad and T. J. Jackson and Kitchen, N.R. and William P. Kustas and McGuire, M.R. and Pinter, P.J. and Sudduth, K.A. and Schepers, J.S. and T. J. Schmugge and Paul F. Starrs and Upchurch, D.} } @article {50800, title = {Sensor development and rediometric correction for agricultural applications}, journal = {Sensor development and rediometric correction for agricultural applications}, volume = {69}, year = {2003}, note = {//NONE//LTER IV//}, month = {2003}, pages = {705-718}, abstract = {

This review addresses the challenges and progress in sensor development and radiometric correction for agricultural applications with particular emphasis on activities within the U.S. Department of Agriculture (USDA) Agricultural Research Service (ARS). Examples of sensor development include on-site development of sensors and platforms, participation in cooperative research and development agreements (CRADA) with commercial companies, and membership on NASA science teams. Examples of progress made in sensor radiometric correction suitable for agriculture are presented for both laboratory and field environments. The direction of future sensor development includes integrated sensors and systems, sensor standardization, and new sensor technologies measuring fluorescence and soil electrical conductivity, and utilizing LIght Detection and Ranging (lidar), hyperspectral, and multiband thermal wavelengths. The upcoming challenges include definition of the core spectral regions for agriculture and the sensor specifications for a dedicated, orbiting agricultural sensor, determination of an operational approach for reflectance and temperature retrieval, and enhanced communication between image providers, research scientists, and users. This review concludes with a number of avenues through which USDA could promote sensor development and radiometric correction for agricultural applications. These include developing a network of large permanent calibration targets at USDA ARS locations; investing in new technologies; pooling resources to support large-scale field experiments; determining ARS-wide standards for sensor development, calibration, and deployment; and funding interagency agreements to achieve common goals.

}, keywords = {Agricultural Applications, Radiometric Correction, Sensor Development}, doi = {10.14358/PERS.69.6.705 }, url = {files/bibliography/JRN00397.pdf}, author = {S. Moran and Fitzgerald, G. and A. Rango and C. Walthall and Barnes, E. and Bausch, W. and Clarke, T. and Daugherty, C. and J. Everitt and J. Hatfield and Kris Havstad} } @article {50801, title = {Soil microtopography on grazing gradients in Chihuahuan Desert grasslands}, journal = {Journal of Arid Environments}, volume = {55}, number = {1}, year = {2003}, month = {September 1, 200}, pages = {181-192}, abstract = {

The significant impacts of livestock in the creation of piospheres centered on water points is the loss of soil microtopography across a {\textquoteleft}landscape{\textquoteright} that has been influenced by many years of livestock grazing. The size, height, and spatial distribution of micromounds and surrounding depressions were measured by a modified erosion bridge at three distances (50, 450, and 1050 m) from water points in desert grassland pastures in the Jornada Basin, New Mexico, USA. Plots at 50m had fewer micromounds and the mounds were smaller than those recorded on the more distant plots. Microtopography of plots at 450m from water was not significantly different from that recorded at 50m. Microtopography of plots that were 1050m from water points was significantly different from that of plots nearer water points. Strong correlation between microtopography and the cover of long-lived perennial grasses (R2=91\%) was found, such dependence could be used for assessing the trend in organic matter content that is in concordance with that of microtopography. Loss of microtopography from the impact of livestock in piospheres exacerbates erosion processes and contributes to desertification.

}, doi = {10.1016/S0140-1963(02)00251-3}, url = {/files/bibliography/03-014.pdf}, author = {M. S. Nash and E. Jackson and Walter G. Whitford} } @article {50825, title = {Spatial patterns, density dependence, and demography in the harvester ant, Pogonomyrmex rugosus, in semi-arid grasslands}, journal = {Journal of Arid Environments}, volume = {53}, year = {2003}, note = {//NONE//NONE//}, month = {2003}, pages = {183-196}, abstract = {To evaluate the relationship between the local spacing patterns of ant colonies and the broad-scale heterogeneity typical of real landscapes, we examine the spacing of colonies of harvester ants (Pogonomyrmex rugosus) on 12 1-ha plots in semi-arid grasslands at the Sevilleta National Wildlife Refuge in New Mexico. We linked land use and topography to colony densities and local spacing patterns, tested the theoretical prediction that regularity should be positively correlated with colony density, and determined the spatial scale of density-dependent recruitment. In general, colonies were regularly spaced at a fine scale. We caution that broad-scale aggregation of colonies can conceal fine-scale regularity. The prediction of density-dependent spacing was supported only within a single topographic position, but not across the entire landscape. Recruitment of new colonies was independent of plot-level densities but depended on locations of established colonies within plots. Landscape heterogeneity can influence the fine-scale spacing of ant colonies, both directly and indirectly, complicating predictions regarding density-dependent spacing. {\textcopyright}2002 Elsevier Science Ltd.}, keywords = {ant colony, density-dependent spacing, ant, colony distribution, ant, demography, ant, harvester, ant, Pogonomyrmex, ant, recruitment, article, articles, demography,ants, journal, journals}, author = {Robert L. Schooley and J.A. Wiens} } @conference {50839, title = {Soil and spatial dependence of landscape dynamics in Chihuahuan Desert grasslands}, booktitle = {17th Annual Symposium, US-International Association for Landscape Ecology}, year = {2002}, month = {April 23-26, 200}, pages = {64}, address = {Lincoln, NE}, abstract = {It is clear that soil properties, landscape position, and nutrient transfers among landscape elements affect the properties of plant communities. Nonetheless, few studies have attempted to account for these variables in explaining plant community dynamics. We examine how changes in grass cover, grass patch structure, and shrub abundance varied on different soils within the southern Jornada del Muerto Basin of New Mexico, USA. Changes in vegetation patterns revealed by repeat photography over 30-40 years (from 1959-2001) were related to detailed measurements of soil properties and geomorphology taken at each photography site as part of the Desert Soil-Geomorphology Project of the Natural Resources Conservation Service. On heavy soils on basin floor or lower piedmont positions, grass patch structure was remarkably stable or patch size increased over the study period. Shrub abundance increased little or even declined. On loamy to sandy soils on upper piedmont positions that were not already devoid of grass, grass cover has declined and shrub abundance and size increased. It is likely that the translocation of water and other resources from degrading sites on upper fan piedmont positions lead to the stability or increases in grass cover observed in downslope landscape positions. These patterns indicate that interpretations of rangeland degradation must account for soils, geomorphology and landscape connectivity.}, author = {Brandon T Bestelmeyer and L. H. Gile and B. Nolen and Curtis H. Monger and Kris Havstad} } @article {50841, title = {Spatial heterogeneity of aggregate stability and soil carbon in semi-arid rangeland}, journal = {Environmental Pollution}, volume = {116}, year = {2002}, month = {2002}, pages = {445-455}, abstract = {

To measure and manage for C sequestration in heterogeneous rangeland systems, we need to more fully understand spatial patterns of soil resources. Spatial distributions of aggregate stability and soil carbon were investigated in a semiarid rangeland in New Mexico, U.S.A. Soil was analyzed from plant interspaces, black grama (Bouteloua eriopoda (Torr.) Torr.), and mesquite (Prosopis glandulosa Torr.) in a landscape-replicated study. Aggregate stability at the 250 micro meter scale, carbonate C, organic C and N, C:N ratio, and glomalin, were all highest under mesquite. Soil C:N ratio was the best predictor of aggregate stability. Estimates of metric tons of C per hectare in the top 10 cm were highly variable at patch and landscape scales, varying from 10.5 under mesquite to 3.0 in interspaces. High variability of aggregate stability and soil C has important implications for C sequestration. We argue that this multi-scale soil heterogeneity must be considered when measuring and managing for C sequestration.

}, doi = {10.1016/S0269-7491(01)00222-6}, url = {/files/bibliography/02-004.pdf}, author = {S.B. Bird and Jeffrey E. Herrick and Wander, M.M. and Wright, S.E.} } @conference {50842, title = {Scale-dependency of approaches: contrasts and comparisons among ecological disciplines}, booktitle = {87th Annual Meeting, Ecological Society of America}, year = {2002}, month = {August 4-9, 2002}, pages = {10}, address = {Tucson, AZ}, abstract = {Numerous approaches have been taken to evaluate spatial scaling relationships in ecology. These approaches can be generalized into three categories{\textquestiondown}those that are non-spatial, those that are spatially explicit but not spatially interactive, and those that are both spatially explicit and spatially interactive. While it is relatively easy to categorize a given study within these three approaches, a more general perspective comparing and contrasting how these approaches are used within different ecological disciplines is largely lacking. Here we compare and contrast case studies related to vegetation-, biogeochemical/hydrological- and animal- dynamics, discuss the implications of selecting a given approach, and note insights that can be obtained from a cross-disciplinary perspective. Understanding these comparisons and contrasts is particularly important in cases where processes from different disciplines need to be coupled to one another. Examples of such cross-disciplinary couplings are highlighted. One case study evaluates scaling approaches for study in which drought produces vegetation mortality (vegetation dynamics) which was initially and subsequently exacerbated by grazing (animal dynamics), and has triggered large increases in runoff, erosion, and losses of carbon and other nutrients (biogeochemical and hydrologicalk dynamics). Our overview provides insights for comparing scaling approaches, being cognizant of implicit assumptions, and providing broader insights on scaling relationships across disciplines in ecology.}, author = {David D. Breshears and K. A. Mitchell and C.D. Allen and Brandon T Bestelmeyer and Gross, J.E. and Curtis H. Monger} } @proceedings {50844, title = {Simulation of grassland-shrubland transition zone landscape images at 650nm using a simple BRDF model}, volume = {6}, year = {2002}, month = {June 24-28, 2002}, pages = {3561-3563}, address = {Toronto, Canada}, abstract = {Grassland-shrubland transition zone landscapes are usually a complex of soils; biotic and abiotic crusts; floristic lifeforms, including C4 grasses, C3 shrubs and semi-shrubs; forbs; cactii; and plant litter. The three-dimensional physical structure of the various elements results in reflectance anisotropy which is described by the surface bidirectional reflectance distribution function (BRDF). The objective of this study was to assess the capability of a simple BRDF model to simulate angular 650nm images of these transition landscapes when driven by a small number of spatially-varying structural parameters (shrub density and width from aerial photogaphy), together with two static parameters (spectral reflectance of leaves and a parametric soil/understory BRDF adjusted against field observations). The model is based on previous work in geometric-optics and radiative transfer codes. Shrub width and number density were estimated for honey mesquite (Prosopis glandulosa), acacia (Acacia spp.) and Mormon tea (Ephedra torreyana); shrub height was estimated from width, while crown height:width ratio was set to 0.75 (oblate). It was hypothesized that this simple parameterization would lead to important errors in simulation of directional (off-nadir) images, by reference to airborne multiangular images acquired at six different viewing directions and three different solar zenith angles close to the solar principal plane. The results show that, when small plants such as broom snakeweed (Gutierrezia sarothrae) are not included in plant density calculation, their large numbers result in an important aggregate effect which can overwhelm the contribution from large plants. The implication is that angular image simulations, using simple models, require estimates of plant densities at both large and small sizes.}, url = {http://ieeexplore.ieee.org/iel5/7969/22041/01027249.pdf?arnumber=1027249}, author = {M. Chopping and A. Rango and Sarah Goslee and T. J. Schmugge and Jerry Ritchie} } @conference {50850, title = {Spectral deconvolution of fllourescence spectra from plant extracts}, booktitle = {44th Rocky Mountain Conference on Analytical Chemistry}, year = {2002}, month = {July 28-August 1}, pages = {134}, address = {Denver, CO}, abstract = {Fluorescence emission spectra have been observed to yield information pertaining to the identification of plant species. One approach to acquiring these characteristic spectra has been to record the spectral signature resulting from an extract of the plant. Often these spectra have been overwhelmed by the fluorescence from chlorophyll species. In an effort to acquire spectral information from less ubiquitous molecular species, plant samples have been extracted using phosphate buffered saline solutions. This has resulted in the acquisition of emission spectra from 370 to 620 nm in the absence of the red chlorophyll fluorescence. The combination of fluorescent and absorbing molecular species extracted from each sample of plant material provides an identifying spectral signature. Variation in solution pH has also been found to provide yet another dimension to the total fluorescence response surface. The results of a study of six plants common to the northern Chihuahuan Desert will be presented. The implications of these findings on the development of a fluorescence-based technique for the identification of plants from pre- and post-digestive samples will also be discussed.}, author = {T.L. Danielson and G.D. Rayson and Anderson, E.M. and Richard E. Estell and E.L. Fredrickson and Kris Havstad} } @proceedings {50851, title = {Spatial and temporal variations in snowmelt degree-day factors computed from SNOTEL data in the upper Rio Grande basin}, year = {2002}, month = {May 20-23, 2002}, pages = {73-80}, address = {Granby, CO}, abstract = {The spatial and temporal variation of degree-day melt factors (DDF{\textquoteright}s) computed from SNOTEL data were evaluated for the Upper Rio Grande Basin to improve modeling and forecasting of snowmelt runoff. Data from seven SNOTEL sites in the Upper Rio Grande Basin were analyzed for the 1996-2000 melt seasons. Average degree-day factors varied among sites with varying density of surrounding forest cover. DDF{\textquoteright}s also varied among years due to incidence of cloudy weather and timing of melt during the season. Degree-day factors for each year at each site generally increased linearly with Julian date during the melt season, but the rate of change increased with site exposure. Best predictions of daily melt using SNOTEL data were obtained using daily degree days, Julian date, and an indicator variable for presence/absence of precipitation. Overall, SNOTEL data produced estimates of daily DDF{\textquoteright}s that were in good agreement with data from previous studies.}, url = {/files/bibliography/02-081.pdf}, author = {D. DeWalle and Henderson, Z. and A. Rango} } @article {50853, title = {Soil quality field tools: Experiences of USDA-NRCS Soil Quality Institute}, journal = {Agronomy Journal}, volume = {94}, number = {1}, year = {2002}, month = {2002}, pages = {33-37}, abstract = {

The mission of the Soil Quality Institute (SQI) of the USDA Natural Resources Conservation Service is to develop and disseminate tools for soil quality assessment. In keeping with this mission, the SQI, through partnerships, has developed two assessment tools for use by farmers and field staff. We review these efforts here. The first, the Soil Quality Card Design Guide, provides a nine-step process for conducting workshops to guide farmers in developing locally adapted soil quality assessment cards. The second, the Soil Quality Test Kit Guide, provides instructions and interpretations for 11 field tests representing physical, chemical, and biological properties of soil. In this paper, we present a summary of soil quality cards developed in seven states. An important strength of the soil quality card design process lies with the active participation of farmers to design the cards themselves as part of locally led conservation activities. We also present results from soil quality test kit training workshops showing that the test kit provides an excellent framework for teaching soil quality concepts in the field. Regular use to compare effects of management systems or monitor changes over time will likely be limited to farmers with fairly high skill levels, specialists, and agricultural consultants.

}, keywords = {assessment tools, field tools, NRCS, soil quality, Soil Quality Institute}, url = {https://naldc.nal.usda.gov/download/11421/PDF}, author = {C. Ditzler and A.J. Tugel} } @conference {50880, title = {Sensitivity testing of the gap intercept method, a simple, rapid indicator of changes in vegetation, soil erosion and hydrologic function}, booktitle = {Eco-Hydrology of Semiarid Landscapes: Interactions and Processes, Chapman Conference}, year = {2002}, month = {September 9-13, }, pages = {17}, address = {Taos, NM}, abstract = {The spatial structure of vegetation is widely recognized as a key factor controlling soil erosion and hydrology in arid and semiarid ecosystems at multiple spatial scales. At the plant-interspace scale, shrub invasion of grasslands may cause little or no change in total plant canopy cover but dramatically increases the area susceptible to wind erosion and reduces resistance to overland water flow. At the patch scale, the development of vegetation bands has been shown to dramatically change both hydrology and primary production. The gap intercept method is designed to detect changes in the proportion of the soil surface covered by gaps between plants larger than a minimum size. Cumulative area and frequency distributions can also be generated from the data. Gaps between both plant canopies and plant bases are recorded along the same line transect. Sensitivity tests completed in relatively degraded and undegraded areas in southern New Mexico showed the method is sensitive to vegetation change and to related changes in wind erosion and can be completed at relatively low cost by individuals with little or no botanical knowledge. We will also present the results of a comparison with a semi-quantitative {\textquestiondown}boot-gap{\textquestiondown} technique designed for use by land managers in conjunction with step-point methods of estimating plant cover and composition.}, author = {Jeffrey E. Herrick and D. E. Gillette and M.D. Remmenga} } @conference {50885, title = {Soil resistance, resilience and quantification of soil and ecological functions}, booktitle = {2002 Annual Meeting, American Society of Agronomy}, year = {2002}, month = {November 10-14, }, pages = {Abstract No. S05}, address = {Indianapolis, IN}, abstract = {Land use practices are sustainable if they result in no net loss of capacity to generate products and services. Retention of this capacity depends on soil and ecosystem resistance and resilience. Most soil properties reflect current capacity. Some reflect resistance and, rarely, resilience. Consequently, we are losing production opportunities on land with low resistance but high resilience and taking unjustified risks on land with high resistance but low resilience. We will present and illustrate a framework and research approach for identifying and evaluating soil properties related to the capacity to maintain essential ecological functions. The framework is based on five premises: (1) Resistance and resilience depend on dynamic interactions between disturbance regime, vegetation and relatively static and dynamic soil properties. (2) New research and paradigms are required to interpret currently available properties. (3) New properties must increasingly reflect soil processes. (4) The properties must reflect ecosystem response to both chronic and episodic stressors, including extreme events. (5) Resistance and resilience must be evaluated at multiple time scales.}, author = {Jeffrey E. Herrick and D.A. Pyke and K. Hipple} } @conference {50890, title = {Simulating small mammal effects on grass-shrub ecotones in arid ecosystems}, booktitle = {17th Annual Symposium, US-International Association for Landscape Ecology}, year = {2002}, month = {April 23-26, 200}, pages = {119}, address = {Lincoln, NE}, abstract = {Several processes leading to shrub encroachment within semiarid and arid grasslands have been identified. However, the role of small animals in shifting dominance between grasses and shrubs at their ecotones has not been well studied, especially in combination with other factors, such as drought, cattle grazing, and soil properties. These potentially interacting factors may have contributed to contradictory results of studies of animal effects on shrub encroachment. The objective of this study was to evaluate the relative importance of small mammals, climate, and soil properties to shifts in the location and composition of grass-shrub ecotones in the Chihuahuan Desert. We used a simulation model to integrate the effects of these factors on the recruitment, growth, and survival of creosotebush (Larrea tridentata), mesquite (Prosopis glandulosa), and black grama (Bouteloua eriopoda). In particular, we were interested in the positive and negative effects of animals on shrub recruitment and grass survival. Simulated timespans over which shrub encroachment occurred into black grama grassland were different for the two shrub species. Effects of animals varied with the shrub and animal species involved. Using these simulation results, we developed a framework for understanding and predicting the role of small mammals in shrub encroachment.}, author = {Hochstrasser, T. and Debra C. Peters and Brandon T Bestelmeyer} } @conference {50901, title = {Simple and weighted averaging approaches to scaling: When can spatial context be ignored?}, booktitle = {17th Annual Symposium, US-International Association for Landscape Ecology}, year = {2002}, month = {April 23-26, 200}, pages = {82}, address = {Lincoln, NE}, abstract = {Scaling from plots to landscapes based on simple or weighted averaging techniques can be powerful and accurate when applied to the appropriate problems. Simple averaging approaches are appropriate when conditions are homogeneous through space and constant through time. Modeling of forest or grassland stands by averaging results from multiple small plots is an example of a simple averaging approach. The assumption of homogeneity is often violated, however, when scaling up to landscapes with topographic or edaphic variability. Weighted averaging approaches can address this variability by simulating the landscape as a collection of discrete patches. For example, estimates of carbon or nitrogen flux across a large region from the CENTURY model are based on a weighted averaging of unique input polygons with distinct combinations of soils and climates. Weighted averaging assumes that the spatial context of patches across a landscape does not influence conditions within a patch. In animal ecology, for example, weighted averaging approaches assume that limitations to patch perception, selection, or dispersal are unimportant over the scale of interest. This paper will draw on examples from plant, animal, and ecosystem ecology to identify when spatial extrapolation can be satisfied by simple or weighted averaging approaches.}, author = {D. R. Lane and Brandon T Bestelmeyer and Parton, B. and K. A. Mitchell} } @conference {50902, title = {Secondary metabolite profiles of palatable and unpalatable populations of ceratoides lanata}, booktitle = {55th Annual Meeting, Society for Range Management}, year = {2002}, month = {February 13-19, }, pages = {Abstract No. 86}, address = {Kansas City, MO}, abstract = {Ceratoides lanata var. lanata (common winterfat) is a prolific chenopod on rangelands throughout the western United States. The plant is valued by livestock producers for its nutrient content and palatability to livestock. The subspecies C. lanata var. subspinosa, native to the southwestern U.S. and northern Mexico, is reported to be unpalatable to livestock. Curiously, fenceline observations of C. lanata var. subspinosa growing north of the Chihuahuan Desert suggest its palatability varies. The availability of palatable and unpalatable phenotypes make C. lanata and C. lanata var. subspinosa useful models to use for identification of secondary compounds influencing diet selection. In this study, actively growing shoots from 10 winterfat populations (10 plants per sampling) in New Mexico, Utah, and west Texas were sampled in early, mid, and late phenological stages. Samples were separated into palatable and nonpalatable populations. Steam distillation of composite samples reveale extremely low levels of volatiles, discouraging further analysis of winterfat volatiles. Nonvolatiles were extracted in 80\% ethanol and separated by liquid chromatography with photodiode array detection. Peaks which differ significantly between populations are being identified by uV and mass spectroscopy and by comparison with standards when available. Differences in chemical profiles between palatable and unpalatable winterfat populations will point to chemicals that influence diet selection among large ruminants.}, keywords = {ceratoides ianata, metabolite profiles, palatable, unpalatable}, author = {M.E. Lucero and Richard E. Estell and D.M. Anderson and E.L. Fredrickson and Kris Havstad and M.D. Remmenga} } @article {50906, title = {Soil classification of arid lands using Thematic mapper data}, journal = {Revista Terra}, volume = {20}, year = {2002}, note = {//?//LTER IV//}, month = {2002}, pages = {89-100}, abstract = {

Soil is an essential part of any terrestrial ecosystem. Scientists, technicians, and farmers have studied its physical and chemical properties for many years for agriculture and soil conservation. These studies usually require field sampling and laboratory analysis that are time-consuming and destructive to the samples being analyzed. Remotely sensed data are an alternative that provide reliable information at low cost based on a non-destructive technique. The objective of this study was\  to evaluate the usefulness of Landsat Thematic Mapper data to classify soils in arid lands. To this end, a Thematic Mapper (TM) scene from the Chihuahuan Desert at Do{\~n}a Ana County, New Mexico, mapped with the Soil\  Taxonomy System, was used. Furthermore, four remote sensing approaches were created to determine the best method to identify soil-mapping units. They were named simple, technical, scaled, and complex. The agreement of TM data and soils maps was tested using the error matrix approach in a supervised classification. Spectral signatures were selected by separability analysis applying the transformed divergency technique. The results revealed that the simple approach, based on thermal band discrimination, obtained classification accuracies of 70.67\%, suggesting bands 2, 4, and 7 as the best for identifying soil mapping units. The technical approach, based on the principal components analysis technique, obtained accuracies of\  66.86\%, suggesting that data reduction is possible through this technique.

}, keywords = {arid lands, article, articles, clasificaci{\'o}n supervisada, classification, firma espectral, journal, journals, landsat, Sensores remotos, soil, Thematic mapper}, url = {files/bibliography/JRN00368.pdf}, author = {J. Martinez-Rios and Curtis H. Monger} } @inbook {50915, title = {Silica minerals}, booktitle = {Soil Minerology with Environmental Applications}, series = {Soil Science Society of America Book Series}, year = {2002}, note = {//LOCAL, NMSU, USDA//LTER IV//ProCite field[6]: in}, month = {2002}, pages = {611-636}, abstract = {

This is a book chapter on silica minerals. It includes sections on 1)structure, composition, and morphology, 2) chemical and physical properties, 3) abundance, distribution, and formation, and 4) their environmental significance.

The silica mineral group is the second most abundant mineral group in the Earth{\textquoteright}s crust, exceeded only by the silicate mineral group, which also has the Si{\textendash}O tetrahedron as its basic building block. While in soil, because of their great abundance and chemical quiescence relative to most other minerals, silica minerals influence several environmentally important soil properties. This chapter describes the physical and chemical properties of silica, its abundance and formation, and its environmental significance with respect to adsorption capacity, respiratory diseases, and landscape stability pertinent to a nuclear waste repository. It also describes the structure, composition, and morphology of silica minerals. X-ray diffraction is the most conclusive method for identifying silica minerals. With respect to soil chemical properties, quartz, which is ubiquitous in most soils, plays an important role because of its tendency to dilute cation exchange capacity, resulting from its low surface area.

}, keywords = {book, books, cation exchange capacity, chapter, chapters, chemical properties, crystal morphology, environmental significance, isotopic composition, minerology, physical properties, Publication History, report, reports, silica, silica minerals, silicon dioxide, SiO2, soil, x-ray diffraction}, doi = {10.2136/sssabookser7.c20}, url = {files/bibliography/JRN00366.pdf}, author = {Curtis H. Monger and Kelley, Eugene F.}, editor = {Dixon, J. B. and Schluze, D. G. (eds.)} } @inbook {50914, title = {Soil inorganic carbon: composition and formation}, booktitle = {Encyclopedia of Soil Science}, year = {2002}, note = {//LOCAL, NMSU, USDA//LTER IV//ProCite field[6]: in}, month = {2002}, pages = {701-705}, publisher = {Marcel-Dekker}, organization = {Marcel-Dekker}, abstract = {Describes composition and formation of soil inorganic carbon.}, keywords = {arid soil, book, books, carbon, composition, formation, carbonate, accumulation, carbonate, geogenic, carbonate, pedogenic, carbonic acid system, chapter, chapters, model, carbonate formation, report, reports, soil, soil formation, soil, argillic horizon, soil, calcic horizon, soil, carbonate, soil, petrocalcic horizon}, author = {Curtis H. Monger and Wilding, Larry P.}, editor = {R. (ed.) Lal} } @conference {50922, title = {Simple and weighted averaging approaches to scaling: when can spatial context be ignored?}, booktitle = {87th Annual Meeting, Ecological Society of America}, year = {2002}, month = {August 4-9, 2002}, pages = {41}, address = {Tucson, AZ}, abstract = {Scaling from plots to landscapes, landscapes to regions, and regions to the globe based on simple or weighted averaging techniques can be accurate when applied to the appropriate problems. Simple averaging approaches work well when conditions are homogeneous spatially and temporally. For example, modelling of grassland and forest stands by averaging results from multiple small plots that have no horizontal transport across the plots is an appropriate use of simple averaging. The assumption of spatial homogeneity is often violated at the landscape and regional scale as a result of topographic and edaphic variability. Weighted averaging approaches can address landscape and regional variability by dividing the area up into a collection of homogeneous discrete patches. This approach has been used successfully for the regional and global Century modelling work where carbon and nitrogen fluxes are calculated as area weighted averages of model output from polygons with distinct combinations of climate and soil properties. Net primary production and soil carbon and nitrogen levels have been successfully extrapolated at the regional and global scale using area weighted averages of model results and observed soils and climate databases. This approach would not work at the landscape level when horizontal fluxes of nutrients and water across the patches are significant and potentially impact the dynamics of the patch. In animal ecology, weighted averaging approaches assume that limitations to patch perception, selection or dispersal are unimportant over the scale of interest. This paper will use examples from biogeochemistry and plant and animal ecology to demonstrate when simple or weighted averaging can be used to spatially extrapolate ecosystem process results.}, author = {William Parton and D. R. Lane and Brandon T Bestelmeyer and K. A. Mitchell and R. Kelly} } @conference {50935, title = {Spectral reflectance differences of northern Chihuahuan Desert vegetation}, booktitle = {87th Annual Meeting, Ecological Society of America}, year = {2002}, month = {August 4-9, 2002}, pages = {415}, address = {Tucson, AZ}, abstract = {Spectral measurements of vegetation communities of the semiarid grasslands in the Jornada Experimental Range LTER and the Sevilleta LTER in New Mexico were measured at ground level using an Analytical Spectral Devices (ASD) Spectrometer on a 30x30 m grid at 5 m intervals, from an airplane with the MODIS/ASTER Simulator (MASTER) with a 3x3 m resolution, and from space with the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) with 15x15 m resolution in May 2001 and with the ASD and ASTER in September 2001. Four communities (Grass, Transition, Mesquite, Creosote) were sampled at the Jornada. Three communities (Grass, Transition, Creosote) were sampled at the Sevilleta. Reflectance increased from Grass to Transition to Shrub communities from all three platforms at both sites. Patterns of reflectance were similar from the three platforms with MASTER and ASTER having the similar absolute values. Comparison of absolute values of ASD ground measurements with MASTER and ASTER measurements differed with different vegetation communities but in general ASD measurement were slightly lower than MASTER or ASTER measurements. These differences are assumed to be related to the different sized footprints of the instruments. In general, as ground cover decreased from Grass to Transition to Shrub communities, reflectance increased indicating a potential for change in heat and water balance of these ecosystems if shrubs continue to expand into the Grass communities.}, author = {Jerry Ritchie and T. J. Schmugge and Jacob, F. and A. Rango and M. Chopping} } @article {50943, title = {Soil carbon dynamics and potential carbon sequestration by rangelands}, journal = {Environmental Pollution}, volume = {116}, number = {3}, year = {2002}, note = {ARIS entry by High Plains Grasslands Research Station July 24, 2001}, month = {March 1, 2002}, pages = {391-396}, abstract = {

The U.S. has about 336 Mha of grazing lands of which rangelands account for 48\%. Changes in rangeland soil C can occur in response to a wide range of management and environmental factors. Grazing, fire, and fertilization have shown to affect soil C storage in rangelands, as has converting marginal cropslands into grasslands. While losses due to soil erosion can influence soil C storage on rangelands, most important is the effect of erosion on soil C redistribution on the landscape through detachment and subsequent deposition. Proper grazing management has been estimated to increase soil C storage on rangelands from 0.1 to 0.3 Mg C ha- yr-1 and new grasslands have been shown to store as much as 0.6 Mg C ha-1 yr-1. Grazing lands are estimated to contain 10-30\% of the world{\textquoteright}s soil organic carbon. Given the size of the C pool in grazing lands we need to better understand the current and potential effects of management on soil C storage.

}, keywords = {carbon,soil, journal, journals, sequestration, carbon, soil}, doi = {10.1016/S0269-7491(01)00215-9}, url = {/files/bibliography/02-088.pdf}, author = {G.E. Schuman and Janzen, H.H. and Jeffrey E. Herrick} } @conference {50956, title = {Spatial variation in shrub invasion and loss of perennial grasses in the Chihuahuan Desert: A multiscale approach}, booktitle = {17th Annual Symposium, US International Association for Landscape Ecology}, year = {2002}, month = {April 23-26, 200}, pages = {30}, address = {Lincoln, NE}, abstract = {Chihuahuan Deserts are characterized by large-scale invasion of perennial grasslands by shrubs over the past century. A number of interacting factors have been implicated in this invasion, including grazing by cattle, drought, herbivory by small animals, and reduction in fire frequency. Spatial variation in shrub invasion has been observed across these landscapes that cannot be explained using plot-scale studies. We investigated the relationship between spatial and temporal variation in these factors and the replacement of perennial grasses by shrubs using permanent 1 m2 quadrats sampled since 193. Quadrats (n=105) were located across the range of soil and plant communities found at the 78,266-ha Jornada Experimental Range LTER site in southern New Mexico, USA. We synthesized additional long-term data collected at multiple spatial scales to identify the factors that influence grass cover in the quadrats. Persistence of the dominant species, black grama, was positively related to processes at the quadrat (sand content, perennial grass production) and landscape scales (distance to nearest shrub-dominated community, variation in spring and winter rainfall). Grass persistence was negatively related to inter-annual variation in grass production. Our results can be used to identify the conditions most resistant to shrub invasion and most likely candidates for remediation.}, author = {Jin Yao and Debra C. Peters and Kris Havstad and Gibbens, Robert P. and Jeffrey E. Herrick} } @article {50957, title = {A sediment transport equation for interrill overland flow on rough surfaces}, journal = {Earth Surface Processes and Landforms}, volume = {26}, year = {2001}, note = {//NONE//LTER IV//}, month = {2001}, pages = {1443-1459}, abstract = {

A model for predicting the sediment transport capacity of turbulent interrill flow on rough sur4faces is developed from 1295 flume experiments with flow depths ranging from 3.4 to 43.4 mm, flow velocities from 0.09 to 0.65 m s-1, Reynolds numbers from 5000 to 26949, Froude numbers from 0.23 to 2.93, bed slopes from 2.7{\textdegree} to 10{\textdegree}, sediment diameters from 0.098 to 1.16 mm, volumetric sediment concentrations from 0.002 to 0.304, roughness concentrations from 0 to 0.57, roughness diameters from 1.0 to 91.3 mm, rainfall intensities from 0 to 159 mm h-1, flow densities from 1002 to 1501 kg m-3, and flow kinematic viscosities from 0.913 to 2.556 x 10-6 m2 s-1. Stones, cylinders and miniature ornamental trees are used as roughness elements. Given the diverse shapes, sizes and concentrations of these elements, the transport model is likely to apply to a wide range of ground surface morphologies. Using dimensional analysis, a total-load transpot equation is developed for open-channel flows, and this equation is shown to apply to interrill flows both with and without rainfall. The euation indicates that the dimensionless sediment transport rate {\O} is a function of, and therefore can be predicted by, the dimensionless shear stress {\`e}, its critical value {\`e}c, the resistance coefficient u/u*, the inertial settling velocity of the sediment wi, the roughness concentration Cr, and the roughness diameter Dr. Testing reveals that the model gives good unbiased predictions of {\O} in flows with sediment concentrations less than 0.20. FLows with higher concentrations appear to be hyperconcentrated and to have sediment transport rates higher than those predicted by the model. Copyright {\textcopyright} 2001 John Wiley \& Sons, Ltd.

}, keywords = {article, articles, hydrology, bedload, hydrology, hillslopes, hydrology, interrill flow, hydrology, overland flow, hydrology, sediment transport, hydrology, soil erosion, journal, journals, model, hydrology, model, interrill overland flow, model, sediment transport}, doi = {10.1002/esp.286}, url = {files/bibliography/JRN00317.pdf}, author = {Athol D. Abrahams and Gary Li and Krishnan, Chitra and Atkinson, Joseph F.} } @article {50990, title = {Supply-limited horizontal sand drift at an ephemerally crusted, unvegetated saline playa}, journal = {Journal of Geophysical Research}, volume = {106}, number = {D16}, year = {2001}, note = {//NONE//LTER IV//entered 07/29/2005; updated 07/28/2008, 07/30/2008}, month = {2001}, pages = {18085-18098}, abstract = {

A site at Owens Dry Lake was observed for more than 4 years. The site was a vegetation-free saline playa where the surface formed {\textquotedblleft}ephemeral crusts,{\textquotedblright} crusts that form after rainfall. Sometimes these crusts were destroyed and often a layer of particles on the crust would engage in vigorous aeolian activity. Three {\textquotedblleft}phases{\textquotedblright} of active sand drifting are defined as almost no movement (extreme supply limitation), loose particles on crust with some degree of sand drift (moderate supply limitation), and unlimited source movement corresponding to a destroyed surface crust (unlimited supply). These {\textquotedblleft}phases{\textquotedblright} occurred 45, 49, and 6\% of the time, respectively. The accumulation of loose particles on the crust was mostly the result of in situ formation. Crusted sediments with loose particles on top can exhibit mass flux rates about the same as for noncrusted sediments. Crusted sediments limit or eliminate sand drift in two conditions: for rough crusts that effect a sufficiently high threshold friction velocity (above the wind friction velocity) and for limited amounts of loose particles on the crust where particle supply is less than would be transported in normal saltation for a thick sandy surface. These {\textquotedblleft}supply-limited{\textquotedblright} cases are similar to wind erosion of limited spilled material on a hard concrete surface. We quantified {\textquotedblleft}supply limitation{\textquotedblright} by defining a {\textquotedblleft}potential{\textquotedblright} or {\textquotedblleft}supply unlimited{\textquotedblright} sand drift function Q = AG where A represents supply limitation that decreases as the particle source is depleted. Here Q is the mass of sand transported through a surface perpendicular to the ground and to the wind and having unit width during time period t, and G = ∫ u*(u2* - u2*t) dt for u* \> u*t. G is integrated for the same time period t as for Q, u* is the friction velocity of the wind, and u*t is the threshold friction velocity of the wind. Hard crusts (usually formed in the summer) tended to show almost no change of threshold friction velocity with time and often gave total protection from wind erosion. Rough crusts provided sufficient protection expressed as high threshold friction velocities. For these high threshold friction velocities, aeolian activity was greatly reduced or practically prevented. The softest crusts, usually formed in the winter, provided much less protection and sometimes were destroyed by the wind. Following this destruction the {\textquotedblleft}potential{\textquotedblright} or {\textquotedblleft}supply unlimited{\textquotedblright} sand drift would be observed.

}, keywords = {aeolian processes, Owen Lake, aeolian processes, particle production, aeolian processes, roughness elements, aeolian processes, transport, aeolian processes, wind erosion, aeolian processes, wind-transported dust, article, journal, Owens Dry Lake}, doi = {10.1029/2000JD900324}, url = {files/bibliography/JRN00346.pdf}, author = {D. E. Gillette and T. Niemeyer and Paula Helm} } @conference {50991, title = {Snowmelt runoff model (SRM) applications in the Rio Grande Basin}, booktitle = {American Water Resources Association Annual Conference}, year = {2001}, month = {November 11, 200}, pages = {49}, address = {Albuquerque, NM}, abstract = {The Snowmelt Runoff Model (SRM) has historically been employed in the Rio Grande basin headwaters for simulation, forecasting and climate change assessment. In the past, the snow cover input required by SRM has been obtained from Landsat and NOAA-AVHRR satellite data. More recently, improved MODIS data on the Terra satellite has been employed to obtain frequent and high resolution snow cover data. Testing the MODIS snow mapping capability has taken place in two similar areas, the Pyrenees Mountains of Spain and the Upper Rio Grande Basin. The evaluation of available water supplies will be extended from the Rio Grande basin to downstream tributaries throughout Colorado and New Mexico. Examples of the snow cover mapping capabilities of MODIS and results of simulation, forecasts and climate change scenarios will be presented.}, author = {E. Gomez-Landesa and A. Rango and Kris Havstad and M. Bleiweiss and Leach, K. and Riley, M.} } @conference {51001, title = {Spatial variability in dynamic soil properties: sampling requirements for a national database}, booktitle = {Annual Meeting, Soil Science Society of America}, year = {2001}, month = {October 15, 2001}, pages = {CD-ROM}, abstract = {Sampling protocols that account for the spatial variability of near-surface dynamic soil properties are required in order to adequately characterize the temporal variability of these properties. The spatial variability of dynamic properties (e.g., SOC, bulk density and infiltration capacity) is not known for most rangeland soils. In order to better define sampling requirements for rangelands, we measured a suite of near-surface dynamic soil properties in paired degraded and relatively undegraded plots located on four different soils representing four different ecological sites in the northern Chihuahuan Desert, southern New Mexico, USA. We calculated the variance in soil and vegetation properties at three different spatial scales: (1) pedon (shrub-interspace), (2) polypedon of a soil map unit component (i.e., 60m diameter circle), and (3) ecological site. Preliminary results suggest that (1) both the scale and magnitude of spatial variability are correlated with vegetation type, (2) sampling requirements can be significantly reduced by using stratified random sampling at the pedon (plant-interspace) scale, and (3) analysis costs can be further reduced by varying the number of samples depending on the level of spatial variability for a particular property.}, author = {Jeffrey E. Herrick and A.J. Tugel and M.D. Remmenga and Laura M. Burkett and Norfleet, L.M. and C. Ditzler} } @article {51010, title = {Spatial heterogeneity in Chihuahuan Desert vegetation: implications for sampling methods in semi-arid ecosystems}, journal = {Journal of Arid Environments}, volume = {47}, year = {2001}, note = {//NMSU,USDA//LTER IV//}, month = {2001}, pages = {257-270}, abstract = {

Patchiness of above-ground vegetation, such as that in semi-arid grasslands and shrublands, can pose problems in sampling plant cover, biomass and productivity. We present a method of measuring above-ground plant biomass and production that can be applied consistently among vegetation types and that generates seasonal, spatially-explicit results. Results from 15 sites within the Jornada Basin (Chihuahuan Desert, New Mexico, USA) confirm considerable patchiness and non-normal distributions of plant biomass, even in grasslands. However, tests of adequacy of sample size and of sample error associated with the regression-based estimates of biomass confirmed that the estimates of above-ground net primary productivity are sufficiently precise to be useful in comparisons of both shrub-dominated and grassland sites.

}, keywords = {article, articles, Bouteloua, net primary production, ecosystem, plant production, journal, journals, Larrea, net primary production, net primary production, plants, net primary production, Prosopis, net primary production, spatial heterogeneity, technique, aboveground NPP}, doi = {10.1006/jare.2000.0678}, url = {files/bibliography/JRN00345.pdf}, author = {L. Huenneke and Clason, Dennis and E. Muldavin} } @article {51017, title = {Satellite measurements of albedo and radiant temperature from semi-desert grassland along the Arizona/Sonora border}, journal = {Climatic Change}, volume = {48}, year = {2001}, note = {//NONE//LTER IV//}, month = {2001}, pages = {417}, abstract = {

Along the international border separating the U.S. (Arizona) and Mexico (Sonora), differences in the grazing intensity of domestic livestock are commonly presumed to have created a large difference in vegetation cover between the two countries. This vegetation difference is reportedly responsible for an extensive albedo and temperature discontinuity that may be affecting regional climate. In this study, we used Landsat Thematic Mapper data to examine trans-border differences in these two biophysical parameters. Albedo and radiant temperature estimates were computed for 25 km-long (east-west) transects through semi-desert grassland on each side of the border at two different times of year. Only small average trans-border differences in these parameters were found, and in some cases average albedo and temperature data were essentially equal on each side of the border. In addition, we found significant spatial heterogeneity in conditions on both sides of the border. These results suggest that, based on a small sample, it may be difficult to assess whether there are significant differences in biophysical properties of semi-arid grassland between Arizona and Mexico in the vicinity of the border. We conclude that more extensive spatial and temporal sampling is critical in assessing any possible trans-border differences in average terrain conditions that might affect climate, and that this data must be coupled with more extensive meteorological data to assess whether a difference in climate also exists.

}, keywords = {article, articles, journal, journals, remote sensing, surface albedo, remote sensing, temperature}, doi = {10.1023/A:1010769416826}, url = {files/bibliography/JRN00343.pdf}, author = {Michalek, J. L. and Colwell, J. E. and Roller, N. E. G. and Miller, N. A. and Kasischke, E. S. and W. H. Schlesinger} } @article {51020, title = {Statistical analyses of fluorometry data obtained from chloroform filtrate of lamb feces}, journal = {Journal of Range Management}, volume = {54}, number = {4}, year = {2001}, month = {July 2001}, pages = {370-377}, abstract = {

Using fecal samples obtained from 13 lambs maintained in metabolism stalls and fed 4 identical basal diets composed of tobosa hay (Pleuraphis mutica) Buckley, which contained 4 different levels (0, 10, 20 and 30\%) of tarbush (Flourensia cernua) D.C. leaf material, a data set of spectral signatures were obtained using fluorometry techniques. A chloroform filtrate obtained from the lamb\&$\#$39;s feces was exposed to xenon light. This caused certain molecules in the filtrate called fluorophores to have their outer shell electrons move to a higher energy state as a result of the energy coming from the xenon light. Upon removal of the xenon light, which had been focused at 310, 320, 330, 340, 350 and 355 nm, the fluorophores returned to their ground state giving off light. This fluorescence light varied in intensity and when captured using appropriate electronics, produced 1024 pairs of light intensities and fluorescent wavelengths between 175 and 818 nm in 0.6288972 increments. This research demonstrated the entire fluorescence data set could be used to determine statistical differences among diets. Five increasingly complex statistical approaches were evaluated: two-dimensional plots, polynomial regression models, confidence interval plots, discriminant analysis and three-dimensional plots. There was a high statistical reliability when separating diets containing no tarbush leaf from diets containing 30\% tarbush leaf; however, it was not possible to routinely statistically separate diets containing intermediate (10 and 20\%) amounts of tarbush leaf material from themselves or the two extremes (0 and 30\% tarbush leaf). These results suggest spectral signatures arising from fluorometry data may be useful for differentiating among diet botanical compositions that differ in plant form.

}, keywords = {chloroform filtrate, fluorometry data, lamb feces, statistical analyses}, url = {/files/bibliography/01-038.pdf}, author = {Mukkherjee, A. and D.M. Anderson and Daniel, D. and L. W. Murray and Tisone, G. and E.L. Fredrickson and Richard E. Estell and G.D. Rayson and Kris Havstad} } @article {51031, title = {Seeing with new eyes: Remote sensing yields insight into Jornada history}, volume = {7}, number = {2}, year = {2001}, note = {Jornada Basin Long-Term Ecological Research Program}, month = {November 2001}, pages = {1-2}, abstract = {Aerial photos of the Jornada Experimental Range from 1937, 1974 and 1986 indicate the land cover has changed greatly and there are unusual features that cannot be accounted for by grazing pattern and pasture boundaries. These features have been identified as rangeland remediation treatments. To confirm they are treatments and to monitor their change with time, additional aerial photography from air photo archiving facilities has yielded data for all or parts of the Jornada Basin for years 1935-1937, 1947-48, 1955, 1960, 1963, 1967, 1972-74, 1977, 1979, 1980, 1986, 1991, 1996 and 1998. Analysis of these data has permitted temporal viewing and assessment of the longevity of rangeland treatments. These include the parallel pattern of grubbed strips (removal of creosote and mesquite shrubs in 1936 by Civilian Conservation Corps labor) on the Chihuahuan Desert Rangeland Research Center and clear identification of water-ponding dikes. These last may be the most effective rangeland treatment; that is, these dikes may result in greater and longer-lasting modification of vegetation than many of the more intensive remediation approaches. More data, including military air photos, are currently being acquired from archives and other sources. Approximately 3000 historical aerial photos will eventually be acquired for the Jornada Basin. These data are being digitized and indexed; in the future, researchers will be able to search an interactive database for aerial photography covering their current or proposed study sites.}, keywords = {aerial photos, Jornada Experimental Range, newsletter, remediation treatments, remote sensing}, url = {/files/bibliography/01-044.pdf}, author = {A. Rango} } @article {51044, title = {Satellite observations of spectral emissivity}, journal = {Global Energy and Water Cycle Conference}, year = {2001}, note = {//USDA//LTER IV//}, month = {2001}, author = {T. N. Schmugge and A.N. French and Jerry Ritchie and A. Rango} } @proceedings {51052, title = {State and transition ecosystem models: Application to soil survey and dynamic soil properties databases}, year = {2001}, month = {June 25, 2001}, pages = {194-201}, address = {Washington, D.C.}, abstract = {Arid and semiarid rangelands are hypothesized to function as nonequilibrium systems. Models that capture these nonequilibrium dynamics at the ecological site level are called state and transition models (STMs). Through the literature, we examined the changes in soil properties that occurred as a result of changes in vegetation on a sandy loam upland site in the shrublands of south Texas. Clay content, bulk density, pH, carbon and nitrogen are compared for herbaceous plant communities and mesquite states. Dynamic soil property data is needed in rangeland management for assessment, prediction and monitoring. State and transition models can provide a database framework for soil characteristics according to soil-plant relationships as well as soil-management interactions that affect soil properties and plant communities over time and at multiple scales. Developing a soil information system or enhancing the National Soil Information System (Natural Resources Conservation Service) for dynamic soil properties will require the reinterpretation of existing data and new observations and experiments. Measurable soil properties that reflect ecological processes and the functional capacity of rangeland soils should be included.}, url = {/files/bibliography/01-060.pdf}, author = {A.J. Tugel and Joel R. Brown} } @proceedings {51122, title = {Soil surface indicators of desertification from the northern Chihuahuan Desert and the Great Basin}, volume = {1}, year = {2000}, month = {July 19-23, 1999}, pages = {137}, address = {Townsville, Australia}, abstract = {We measured vegetation canopy and litter cover in ungrazed exclosures and adjacent pastures at three locations in the Chihuahuan Desert, five locations near Burns, Oregon, seven locations near Milford, Utah, and six near Idaho Falls, Idaho, all of which are in the Great Basin. We found that vegetation cover is not a good surrogate for estimating litter cover. Refinements that take into account vegetation species composition may improve the ability to predict litter cover from vegetation data.}, keywords = {Chihuahuan Desert, desertification, Great Basin, indicators, soil surface}, url = {/files/bibliography/00-002.pdf}, author = {A.G. de Soyza and Walter G. Whitford and Justin Van Zee and Jeffrey E. Herrick and Kris Havstad} } @proceedings {51072, title = {Snow mapping technique at subpixel level for small basins}, year = {2000}, note = {ARIS entry at Beltsville}, month = {July 24-28, 2000}, pages = {1140-1142}, address = {Honolulu, HI}, abstract = {Snow cover mapping is often carried out using optical satellite imagery. In this paper we address the problem of snow mapping of small basins with areas only 10 times the spatical resolution of the sensor using subpixel analysis. This technique is currently being used in several basins in the Spanish Pyrenees and has been developed as part of a snow cover mapping and snowmelt runoff forecasting system which uses snow cover as an input for the Snowmelt Runoff Model (SRM). Spanish hydropower companies receive the snowmelt forecasts and use them as criteria in decision making for reservoir management. The accuracy of the forecasts strongly depends on the snow cover accuracy.}, keywords = {forecasting, small basins, snow mapping, SRM, subpixel level}, url = {/files/bibliography/00-013.pdf}, author = {E. Gomez-Landesa and A. Rango} } @conference {51075, title = {The Sevilleta long-term ecological research program}, booktitle = {85th Annual Meeting, Ecological Society of America}, year = {2000}, month = {August 6-10, 200}, pages = {387}, address = {Snowbird, UT}, abstract = {

The Sevilleta Long-Term Ecological Research Program, established in 1988, conducts research on ecological processes and responses to climate dynamics in a biome transition zone in central New Mexico. The major site is the Sevilleta National Wildlife Refuge operated by the U.S. Fish and Wildlife Service. The primary goal of the LTER Program is to develop and test a hierarchical model of controls and constraints on the movements of biotic assemblages at the edges of their distributions. These movements occur as a result of complex interactions among a large number of biotic and abiotic variables at a wide range of spatial scales and over time periods ranging from minutes to centuries. The Sevilleta LTER models and experiments address the relative roles of the major controlling variables and allow predictions of changes in the structure and functioning of biome transition zones that would result from natural (e.g., climate) and anthropogenic (land use, grazing, fire) perturbations. Of particular interest is the role of moisture availability (drought cycles, El Nino/La Nina episodes, Pacific Decadal Oscillations) in driving the distributional expansion and contraction of C3 and C4 plant species over decadal time frames and the resulting changes in local and landscape-level ecological processes. The results of these studies will provide a greater understanding of the physical and biological processes that govern the dynamics of the major ecosystems in New Mexico, factors that lead to desertification processes and contribute to improved understanding and management of the environment for sustainable human use and development.

}, keywords = {biome tranisition zones, ecological research, predictions, Sevilleta LTER, variables}, author = {J. R. Gosz and R. R. Parmenter and Debra C. Peters and David C. Lightfoot} } @article {51082, title = {Soil quality: An indicator of sustainable land management?}, journal = {Applied Soil Ecology}, volume = {15}, number = {1}, year = {2000}, month = {August 1, 2000}, pages = {75-83}, abstract = {

Soil quality appears to be an ideal indicator of sustainable land management. Soil quality, by definition, reflects the capacity to sustain plant and animal productivity, maintain or enhance water and air quality, and promote plant and animal health. Few land managers have adopted soil quality as an indicator of sustainable land management. There are a number of constraints to adoption. Most could be overcome through a concerted effort by the research community. The following issues need to be addressed: 1) Demonstrate causal relationships between soil quality and ecosystem functions, including biodiversity conservation, biomass production and conservation of soil and water resources. 2) Increase the power of soil quality indicators to predict response to disturbance. Although there are many indicators that reflect the current capacity of a soil to function, there are few that can predict the capacity of the soil to continue to function under a range of disturbance regimes. 3) Increase accessibility of monitoring systems to land managers. 4) Integrate soil quality with other biophysical and socioeconomic indicators. 5) Place soil quality in a landscape context. In conclusion, soil quality is a necessary but not sufficient indicator of sustainable land management. Its value will continue to increase as limitations are diminished through collaboration between scientists, land managers and policy makers.

}, keywords = {constraints, indicator, land management, soil quality}, doi = {10.1016/S0929-1393(00)00073-1}, url = {/files/bibliography/JRN00312.pdf}, author = {Jeffrey E. Herrick} } @article {JRN54977, title = {Snow crystal imaging using scanning electron microscopy: III. Glacier ice, snow and biota}, journal = {Hydrological Sciences}, volume = {45}, year = {2000}, month = {06/2000}, pages = {357-375}, chapter = {357}, abstract = {

Low-temperature scanning electron microscopy (SEM) was used to observe metamorphosed snow, glacial firn, and glacial ice obtained from South Cascade Glacier in Washington State, USA. Biotic samples consisting of algae (Chlamydomonas nivalis) and ice worms (a species of oligochaetes) were also collected and imaged. In the field, the snow and biological samples were mounted on copper plates, cooled in liquid nitrogen, and stored in dry shipping containers which maintain a temperature of-196{\textdegree}C. The firn and glacier ice samples were obtained by extracting horizontal ice cores, 8 mm in diameter, at different levels from larger standard glaciological (vertical) ice cores 7.5 cm in diameter. These samples were cooled in liquid nitrogen and placed in cryotubes, were stored in the same dry shipping container, and sent to the SEM facility. In the laboratory, the samples were sputter coated with platinum and imaged by a low-temperature SEM. To image the firn and glacier ice samples, the cores were fractured in liquid nitrogen, attached to a specimen holder, and then imaged. While light microscope images of snow and ice are difficult to interpret because of internal reflection and refraction, the SEM images provide a clear and unique view of the surface of the samples because they are generated from electrons emitted or reflected only from the surface of the sample. In addition, the SEM has a great depth of field with a wide range of magnifying capabilities. The resulting images clearly show the individual grains of the seasonal snowpack and the bonding between the snow grains. Images of firn show individual ice crystals, the bonding between the crystals, and connected air spaces. Images of glacier ice show a crystal structure on a scale of 1-2 mm which is considerably smaller than the expected crystal size. Microscopic air bubbles, less than 15 firn in diameter, clearly marked the boundaries between these crystal-like features. The life forms associated with the glacier were easily imaged and studied. The lowtemperature SEM sample collecting and handling methods proved to be operable in the field; the SEM analysis is applicable to glaciological studies and reveals details unattainable by conventional light microscopic methods.

}, url = {files/bibliography/Rango2000-03.pdf}, author = {A. Rango and W.P. Wergin and E. R. Erbe and E. G. Josberger} } @article {51130, title = {Short-term patterns in water and nitrogen acquisition by two desert shrubs following a simulated summer rain}, journal = {Plant Ecology}, volume = {145}, year = {1999}, note = {//USDA/LTER III//}, month = {1999}, pages = {27-36}, abstract = {

A field experiment was conducted to compare the rapidity with which the shrubs Larrea tridentata and Prosopis glandulosa utilized water, CO2 and nitrogen (N) following a simulated summer rainfall event. Selected plants growing in a roughly 50-m2 area were assigned to treatment and control groups. Xylem water potential ({\O}x) and net assimilation rate (Anet) were evaluated one day before and one and three days after watering. To monitor short-term N uptake, soils around each plant were labeled with eight equally distant patches of enriched 15N before watering. Nitrogen uptake, measured as leaf {\"a}15N, was evaluated at smaller time intervals and for a longer period than those used for {\O}x and Anet. Both {\O}x and Anet exhibited a significant recovery in watered vs. control Larrea plants within 3 days after the imposition of treatment, but no such recovery was observed in Prosopis in that period. Larrea also exhibited a greater capacity for N uptake following the rain. Leaf {\"a}15N was 5-fold greater in watered compared to unwatered Larrea plants within 2 days after watering, while foliar {\"a}15N was not significantly different between the watered and unwatered Prosopis plants during the same period. Lack of a significant change in root 15NO3 uptake kinetics of Larrea, even 3 days after watering, indicated that the response of Larrea to a wetting pulse may have been due to a greater capacity to produce new roots. The differential ability of these potential competitors in rapidly acquiring pulses of improved soil resources following individual summer rainfall events may have significant implications for the dynamic nature of resource use in desert ecosystems.

}, keywords = {article, articles, isotopes, nitrogen, journal, journals, nitrogen, isotopes, nitrogen, shrub acquisition, rainfall simulation, shrubs, shrub, rainfall simulation, water, shrub acquisition}, doi = {10.1023/A:1009819516976 }, url = {files/bibliography/JRN00286.pdf}, author = {H. BassiriRad and Tremmel, D. C. and R. A. Virginia and J. F. Reynolds and A.G. de Soyza and Brunell, M. H.} } @article {51134, title = {Shrub invasion of grassland: recruitment is continuous and not regulated by herbaceous biomas or density}, journal = {Ecology}, volume = {80}, number = {7}, year = {1999}, month = {1999}, pages = {2385-2396}, keywords = {biomass, density, grassland, herbaceous}, url = {/files/bibliography/99-011.pdf}, author = {Joel R. Brown and Steven R. Archer} } @article {51136, title = {Stable isotopes and soil-geomorphology as indicators of Holocene climate change, northern Chihuahuan Desert}, journal = {Journal of Arid Environments}, volume = {43}, year = {1999}, note = {//LOCAL//LTER III//}, month = {1999}, pages = {357-373}, abstract = {

Coeval {\"a}13 C shifts recorded in buried soils at both piedmont slope and basin floor sites in the northern Chihuahuan Desert indicate a major shift from C4 grasses to C3 desert-scrub between 7 and 9 ka. The age assignments are based on stratigraphic correlations to charcoal dates and carbon-14 dates of carbonate. This shift is synchronous with a period of cooling in the North Atlantic that may have triggered a period of drought in the southwestern United States. Coinciding with this vegetation change, geomorphic evidence in Rio Grande, piedmont, and basin floor eolian environments indicates a major period of erosion. Subsequent gradual enrichment of pedogenic carbonate {\"a}13 C values in younger deposits suggests that C4 grasses rebounded in the late Holocene (approximately 4 ka), which is consistent with other evidence of increased moisture regionally. A period of less severe aridity at approximately 2.2 ka is indicated by erosion and subsequent deposition along the alluvial fans and within the basin, and correlates with depleted pedogenic carbonate {\"a}13 C values suggesting a decrease in C4 grasses. Isotope and packrat midden records should be used together to infer past environmental conditions at different elevations.

}, keywords = {article, articles, climate change, geomorphology, climate change, isotopes, geomorphology, climate change, geomorphology, isotopes, Holocene, climate change, journal, journals, soil, geomorphology}, doi = {10.1006/jare.1999.0584}, url = {files/bibliography/JRN00292.pdf}, author = {B. J. Buck and Curtis H. Monger} } @inbook {51138, title = {Soil Structure}, booktitle = {LTER Soil Methods Standardization}, year = {1999}, note = {//?//LTER III//}, month = {1999}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, keywords = {book, books, chapter, chapters, report, reports, soil structure}, author = {Elliott, E. and Coleman, D. C. and M. Harmon and E. Kelly and Curtis H. Monger}, editor = {Roberston, P.} } @inbook {51151, title = {Site and landscape characterization for ecological studies}, booktitle = {Standard soil methods for long-term ecological research}, year = {1999}, note = {//??//LTER III//}, month = {1999}, pages = {29-52}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, abstract = {

There is growing awareness of the importance of adequately defining the environment when conducting ecological studies. Our objective in this chapter is to present the rationale and procedures for describing soils and landscapes (sites) for such studies. We use the term site characterization to refer to the entire suite of soil biogeophysical descriptors that places a site into an environmental context. A primary goal of any environmental study is to understand a phenomenon or set of linked phenomena, whether attributes or processes. Macro- and miroclimate, soil and landscape properties influence bot6h ecosystem attributes and processes. To understand our own data or those of others, we must understand the environment in which they were collected. In addition, we are increasingly called upon to apply our research results to land management issues. Extrapolation from study sites can be either statistically rigorous or qualitative. Both understanding than extrapolation demand good site characterization.

}, keywords = {book, books, chapter, chapters, report, reports, soil, methods, technique, soil methods}, url = {files/bibliography/JRN00287_0.pdf}, author = {D. Grigal and Bell, J. C. and R. J. eds. Ahrens and Boone, R. D. and E. Kelly and Curtis H. Monger and P. Sollins}, editor = {Roberston, G. P. and Coleman, D. C. and Bledsoe, C. S. and P. Sollins} } @article {51152, title = {Structure of desert seed banks: comparisons across four North American desert sites}, journal = {Journal of Arid Environments}, volume = {42}, year = {1999}, note = {//NMSU//IBP//}, month = {1999}, pages = {1-14}, abstract = {The similarities and differences in seed bank structure across four locations in the North American deserts (Curlew Valley, Utah in the Great Basin; Rock Valley, Nevada in the Mojave Desert; Silverbell, Arizona in the Sonoran Desert; and Jornada, New Mexico in the chihuahuan Desert) were compared using published data. Species composition at Curlew Valley was most distinctive among the four study sites. In all four sites, average seed size decreased in this order: shrub, herbaceous perennial, and annual species. Mean seed sizes were similar across the Curlew Valley, Rock Valley and Silverbell sites but much smaller at the Jornada site. Most species have small seeds, but the number of seeds varied greatly among these small-seeded species; i.e. seeds of these species could be highly abundant or very rare in the seed banks. In contrast, very few species have large seeds and the seeds of these species were always rare. The possible roles of underlying soil and climatic factors in structuring desert seed bank structure are discussed.}, keywords = {article, articles, growth form, journal, journals, North American deserts, seed bank, seed size}, author = {Guo, Qinfeng and P. Rundel and D. W. Goodall} } @inbook {51162, title = {Soil water and temperature status}, booktitle = {LTER Soil Methods Standardization}, year = {1999}, note = {// //LTER III//ProCite field[6]: In}, month = {1999}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {Oxford}, abstract = {

Soil water status and temperature are critical factors that affect the activity of organisms in soils. Soil water content also has important effects on the quantity of water that eventually becomes available to surface water, both through its influence on infiltration/runoff relationships (wet soils have lower infiltration rates) and because of its potential contribution to the groundwater. Soil temperature influences soil water availability, the growth rates of plants and microorganisms, and rates of chemical/biochemical reactions.

A number of useful soil physics texts are available that cover the general theory and application of soil water and temperature (e.g., Baver et al. 1972; Hillel 1980a, 1980b; Marshall and Holmes 1988).\  In addition, several books contain detailed summaries of current measurement techniques (Klute 1986; Smith and Mullins 1991; Topp et al. 1992). These references should be used to supplement material in this chapter.

Soil water content has been measured for many years. Earliest measurements were semi quantitative. To the experienced fieldworker, the appearance and feel of the soil can provide valuable information on the amount of water it contains, especially the total water content. Wet soils are generally darker than dry soils and feel "smoother" and heavier. However, appearance and feel can be deceiving. Furthermore, they do not provide quantitative measures of soil water status. Earliest measures of soil water content involved collecting a moist field sample, weighing it, drying it in air or in an oven, and determining the weight loss. Weight loss on drying at 100- 110 {\textdegree}C is usually attributable to water evaporation. The ratio of weight loss to dry weight has been termed gravimetric soil water content.

}, keywords = {book, books, chapter, chapters, report, reports, soil temperature, soil, methods, soil, moisture, technique, soil methods, technique, soil temperature, technique, soil water}, author = {W. M. Jarrell and Armstrong, D. and D. Grigal and E. Kelly and Curtis H. Monger and D. Wedin}, editor = {Robertson, G. P. and Coleman, D. C. and Bledsoe, C. S. and P. Sollins} } @article {51164, title = {Soil microarthropods as indicators of exposure to enviromental stress in Chihuahuan Desert rangelands}, journal = {Biololgy and Fertility of Soils}, volume = {28}, year = {1999}, month = {1999}, pages = {121-128}, abstract = {

We studied soil microarthropod communities along livestock grazing disturbance gradients, inside and outside grazing exclosures, and on areas subjected to restoration efforts (herbicide and bulldozing) in order to test the suitability of mites as indicators of rangeland soil quality. We found that mite numbers generally increased with decreased grazing disturbance. Soil microarthropods appeared to respond to a complex of factors including soil compaction, depth to an impervious soil layer, below-ground vegetative biomass, and residual effects of herbicide. All of our study plots, except those that had been herbicide treated, were dominated by microbivorous mites of the family Nanorchestidae. The numerical responses of mites, especially nonorchestids, appeared to provide a sensitive indicator of ecosystem health in a Chihuahuan Desert grassland.

}, keywords = {desert grassland, desertification, grazing, Herbicides, indicators.}, doi = {10.1007/s003740050472}, url = {/files/bibliography/669.pdf}, author = {F. R. Kay and Sobhy, H. M. and Walter G. Whitford} } @article {51163, title = {Soil microarthropods as indicators of exposure to environmental stress in Chihuahuan desert rangelands}, journal = {Biology and Fertility of Soils}, volume = {28}, year = {1999}, note = {//NMSU, USDA //LTER III//}, month = {1999}, pages = {121-128}, abstract = {

Soil microarthropod communities were studied along livestock grazing disturbance gradients, inside and outside grazing exclosures, and on areas subjected to restoration efforts (herbicide and bulldozing) in order to test the suitability of mites as indicators of rangeland soil quality. We found that mite numbers generally increased with decreased grazing disturbance. Soil microarthropods appeared to respond to a complex of factors including soil compaction, depth to an impervious soil layer, below-ground vegetative biomass, and residual effects of herbicide. Microbivorous mites of the family Nanoarchestidae dominated all of our study plots, except those that had been herbicide treated. The numerical responses of mites, especially nanorchestids, appeared to provide a sensitive indicator of ecosystem health in Chihuahuan Desert grassland.

}, keywords = {article, articles, ecosystem health, indicators, ecosystem health, soil biota, journal, journals, microarthropod, soil, rangeland health, indicators, soil, microarthropod}, doi = {10.1007/s003740050472}, url = {files/bibliography/JRN00288.pdf}, author = {F. R. Kay and Sobhy, H. M. and Walter G. Whitford} } @article {51173, title = {Spatial and temporal variability in relative abundance and foraging behavior of subterranean termites in desertified and relatively intact Chihuahuan Desert ecosystems}, journal = {Applied Soil Ecology}, volume = {12}, year = {1999}, month = {1999}, pages = {149-157}, abstract = {

The annual feeding activity on paper baits of subterranean termites in desertified (degraded-shrub dominated ecosystems) and relatively undegraded black-grama (Bouteloua eriopoda) grasslands was measured over six years on 12 sites. There were no significant differences in mass losses from termite baits among the desertified and undesertified sites. Mass of paper consumed by termites on two sites dominated by creosotebush, Larea tridentata, was higher than on the other 10 sites. These sites were characterized by shallow, coarse soils and shrubs that did not retain a below-canopy litter layer. The spatial locations of the highest termite bait removal remained relatively constant over the duration of the study. Interannual variations in mass losses from termite baits were highly correlated with winter{\textendash}spring rainfall (r2 between 0.60 and 0.95) except at one site on shallow soils. The relationship between annual rainfall and termite activity was less significant (r2 between 0.48 and 0.83). Frequency of attack as measured by percent of bait rolls {\textquotedblleft}hit{\textquotedblright} were not different among sites indicating no differences in densities of subterranean termites. Degradation of Chihuahuan desert grasslands and associated vegetation change has had minimal effect on the activity of subterranean termites. Subterranean termites continue to affect soil properties and processes in both degraded (desertified) and undesertified ecosystems.

}, keywords = {desert grassland, desertification, dunes, Shrub-lands, Subterranean termites}, doi = {10.1016/S0929-1393(98)00164-4}, url = {/files/bibliography/673.pdf}, author = {M. S. Nash and John P. Anderson and Walter G. Whitford} } @proceedings {51179, title = {Spatial assessment of desertification in terms of vegetation pattern and available soil nitrogen}, year = {1999}, note = {//USDA//LTER III//ProCite field[6]: In}, month = {1999}, publisher = {Texas Tech University Press}, address = {Texas Tech University}, abstract = {The objective of this study was to use spatial statistics to quantify the effects of desertification on the distribution of biomass and available nitrogen in Chihuahuan desert black grama (Bouteloua eriopoda) grassland, which has been invaded by honey mesquite (Prosopis glandulosa) shrubland. This research is a portion of analysis of spatial patterns and interrelationships of ecological variables across a desertification gradient, with the larger goal of being to improve our understanding of the mechanisms underlying desertification in southwestern ecosystems. This study tested the sensitivity of "Geostatistics" and "Spatial statistics" to detect subtle differences between ecosystems, such as those occurring across a continuous gradient of desertification.}, keywords = {abstract, abstracts, Bouteloua, resource distribution, conference, conference proceedings, conferences, desertification, soil nitrogen, desertification, vegetation, geostatistics, grassland, desertification, methods, SEE , proceeding, proceedings, Prosopis, resource distribution, shrubland, desertification, soil nitrogen, desertification, spatial statistics, technique, geostatistics, technique, spatial statistics, vegetation change, desertification}, author = {A. M. Pilmanis and W. H. Schlesinger}, editor = {Taylor, Idris Rhea and H. E. Dregne and Mathis, Kary (eds.)} } @article {51188, title = {Soil resilience: A fundamental component of soil quality}, journal = {Soil Science}, volume = {1644}, year = {1999}, month = {April 1, 1999}, pages = {224-234}, abstract = {

Soil resilience has recently been introduced into soil science to address sustainability of the soil resource and to combat soil degradation. The concept of soil resilience and its relationship to soil quality have not been well defined or developed. The main objectives of this paper are to clarify the concept of soil resilience and its relationship to soil quality yand to present a framework for its assessment. A review of the literature on the assessment and quantification of soil resilience is presented and discussed. The concept of soil resilience in combination with resistance is presented as an important component of soil quality, a key element of sustainability. Factors that affect soil resilience and resistance are soil type and vegetation, climate, land use, scale, and disturbance regime. Maintenance of recovery mechanisms after a disturbance is critical for system recovery. Three approaches for assessing soil resilience are presented: (1) directly measuring recovery after a disturbance, (2) quantifying the integrity of recovery mechanisms after a disturbance, and (3) measuring properties that serve as indicators of those recovery mechanisms. Research is needed in the development of indicators or quantitative measures of the ability of soils to recover from specific disturbances.

}, keywords = {assessment, definition, indicators., soil function, soil quality, soil resilience, soil resistance}, doi = {10.1097/00010694-199904000-00002}, url = {/files/bibliography/533.pdf}, author = {C. Seybold and Jeffrey E. Herrick and Brejda, J.J.} } @article {51200, title = {Seasonal and diurnal activity patterns in ant communities in a vegetation transition region of southeastern New Mexico (Hymenoptera: formicidae)}, journal = {Sociobiology}, volume = {34}, number = {3}, year = {1999}, month = {December 1, 1999}, pages = {477-491}, abstract = {

The densities of active ant colonies were estimated in three habitats: creosotebush shrubland, grassland, and shinnery-oak mesquite dunes. Diurnal foraging patterns were studied at bait boards. Species richness of ant communities in this transitional region (8-12 species) was considerably lower than Chihuahuan Desert ant communities in an area with lower annual average rainfall. The numerically dominant species was Forelius pruinosus. Crematogaster spp. Was subdominant in all of the habitats and exhibited relatively constant activity throughout the growing season. Harvers ants, Pogonomyrmex spp. Exhibited different seasonal activity patterns in the three habitats. One species, Trachymyrmex septentrionalis, was not recorded until October, when its nests were conspicuous with discarded leaf fragments around the entrances. Several species of ants feeding at bait board extended their foraging times in comparison to colonies of the same species too distant from the bait boards for foragers to reach the baits. Only one species (Pogonomyrmex apache) exhibited a high-tolerance foraging behavior by initiating foraging at the bait boards after soil surface temperatures exceeded 40{\textordmasculine}C and other species had ceased foraging. Foraging activity of most species continued throughout the day when cloud cover reduced soil surface temperatures to 40{\textordmasculine}C during midday.

}, keywords = {ant communities, diurnal activity, seasonal activity, vegetation transition}, url = {/files/bibliography/695.pdf}, author = {Walter G. Whitford} } @article {51209, title = {The spatial distribution of termite activity in shortgrass steppe: a geostatistical approach}, journal = {Oecologia}, volume = {114}, year = {1998}, note = {//OTHER//NONE//}, month = {1998}, pages = {410-416}, abstract = {The broad-scale distribution of subterranean termites (Reticulitermes tibialis) was studied in a shortgrass-steppe ecosystem in northern Colorado. Termite occurrence and abundance was measured over 4 months at 10-m intervals along a 900-m transect that spanned a topographic gradient. Geostatistics were used to model the probability of termite occurrence along the transect, and to identify the distributional extent and potential roles of termites in shortgrass steppe.... Termites were most frequently found on a south-facing slope and in a lowland swale. Four-wing slatbush (Atriplex canescens) was also common in these areas and is important in the production of woody litter. The distribution of termites was significantly asociated with proximity to saltbush, which showed a strong spatial dependence at scales < 500 m. Kriged probabilities of occurrence and cross-correlation between termites and shrubs showed that peak termite occurrence was shifted upslope 100 m from areas of closest shrub proximity. Other factors, such as soil temperature, texture, or organic matter, are therefore likely to influence termite distributions in shortgrass steppe.}, keywords = {article, articles, geostatistics, termites, Gnathamitermes, journal, journals, kriging, spatial scale, technique, kriging, technique, spectral analysis, termite, activity, termite, gallery carton, termite, litter decomposition, termite, spatial variability, termites , SEE , topography, termites}, author = {Crist, Thomas O.} } @article {51217, title = {Soil-induced variability in root systems of creosotebush (Larrea tridentata) and tarbush (Flourensia cernua)}, journal = {Journal of Arid Environments}, volume = {39}, number = {1}, year = {1998}, month = {May 1, 1998}, pages = {57-78}, abstract = {

Creosotebush (Larrea tridentata) and tarbush (Flourensia cernua) are two of the major shrub invaders of grassland in many desert areas of southern New Mexico. Soils and root systems associated with these two shrubs were studied at three sites on an alluvial fan piedmont. The soils have formed in alluvium derived from monzonite, rhyolite, and andesite, in deposits ranging in age from late Holocene to middle Pleistocene. Soil age, carbonate morphology, particle size, and landscape position were found to be major factors associated with root variability. The stage I carbonate that occurs in youngest soils has relatively little influence on root distribution because the carbonate consists only of thin coatings on sand grains and pebbles. But the increasing carbonate that occurs in stages II, III, and IV results in denser zones of carbonate that control the routes for movement of both soil water and roots. Not only do individual nodules and cemented pebbly zones grow and eventually merge, they also represent zones of restricted hydraulic conductivity, funneling soil water and roots to as yet uncemented parts of the horizon. Continued carbonate accumulation leads to a plugged horizon and an overlying stage IV laminar horizon that is a barrier to roots. Particle size controls the time and amount of carbonate required for formation of these horizons. Calciargids of late Pleistocene age that averaged 4\% and 32\% by volume of gravel and contained 415 and 317\ kg\ m-2 of pedogenic carbonate had only stage III horizons. In contrast, a Petrocalcid of the same age and averaging 63\% by volume of gravel required only 205\ kg\ m-2 of carbonate to form the stage IV horizon. Roots penetrated occasional openings in the stage IV horizon. Runoff from soils sloping 2\% reduces the number of days with available soil water at various depths as compared to 1\% slopes below. At the 2\% slope, roots did not extend below 2\ m depth, whereas at the 1\% slope roots extended to as much as 5\ m depth.

}, keywords = {Calciargids, calcic horizons, hydraulic conductivity, petrocalcic horizons, Petrocalcids, root depth, root distribution, root morphology, stages I{\textendash}IV of carbonate accumulation}, doi = {10.1006/jare.1998.0377}, url = {/files/bibliography/614.pdf}, author = {L. H. Gile and Gibbens, Robert P. and J.M. Lenz} } @article {JRN54961, title = {Snow Cover Remote Sensing and Snowmelt Runoff Forecasts in the Spanish Pyrenees Using the SRM Model }, journal = {Applications of Remote Sensing in Hydrology}, year = {1998}, month = {11/1998}, pages = {97-104}, abstract = {

Snowmelt runoff forecasts are being carried out using the SRM mode in several basins of the Spanish Pyrenees. \ These results are being used by hydropower companies of Spain for a reasonable management of water resources. We describe a method for snow mapping using NOAA-AVHRR data and a procedure to retrospectively estimate the accumulated snow water equivalent volume with the SRM model. A linear combination of NOAA channels 1 and 2 is used to obtain a snow cover image in which the product is the percent of the snow covered area in each pixel. Real-time snowmelt forecasts are being carried out with the Snowmelt Runoff Model (SRM) using the snow covered area as an input. Even in basins with a total absence of historical discharge and meteorological data, the SRM model provides an estimation of the snowmelt daily discharge. Integrating the forecasted streamflow over the recession streamflow, the snowmelt volume is obtained as a function of time. The function converges asymptotically to the net stored volume of water equivalent of the snowpack.

}, url = {files/bibliography/Rango1998-03.pdf}, author = {E. Gomez-Landesa and A. Rango} } @proceedings {51222, title = {Site and cover effects on event runoff, Jornada Experimental Range, New Mexico}, year = {1998}, note = {//NMSU,USDA//LTER-III//ProCite field[2]: Processor and Program Chair. Professor and ChairmanProCite field[6]: Paper presented at}, month = {May 27-19, 19981}, publisher = {AWRA}, address = {Reno, NV}, abstract = {

Event rainfall depth, runoff depth, and periodic cover density measurements were taken for a total of 21 plots (2mx2m) at 5 different locations on the National Science Foundation Jornada Long-Term Ecological Research Site in southern New Mexico. Runoff properties are characterized by plot, plot group, and site using Curve Number (CN) analysis. Results show differences within groups, between groups and with cover. Distinct trends of CN with cover are seen with the effects being most profound at the better sites (lower CN). However, a near-common value (CN~90) is projected for all brush sites under conditions of no cover. These findings affirm customary but seldom-demonstrated expectations, and indicate that the most hydrologic improvement per unit of cover would be on the better sites (lower CN), and the futility of vegetation management for hydrologic benefits on the harsher sites (high CN).

}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, hydrology, rainfall-runoff, precipitation, runoff, proceeding, proceedings}, url = {files/bibliography/JRN00263.pdf}, author = {Hawkins, Richard H. and Timothy J. Ward} } @proceedings {51225, title = {Soil organisms and rangeland soil hydrological functions}, volume = {PNW-GTR-461}, year = {1998}, month = {March 17-19, 199}, pages = {91-100}, publisher = {USDA Forest Service, Pacific Northwest Research Station}, address = {Corvallis, OR}, abstract = {

Soil organisms control water distribution in rangelands by creating macropores which rapidly conduct water into the soil, by generating stable soil aggregates which prevent crusting and increase water holding capacity, and by controlling litter decomposition. Ants, termites and earthworms have all been shown to increase infiltration capacity; anecdotal evidence suggests that macropore formation by a variety of other macroinvertebrate may have equally dramatic effects. Macroinvertebrates generate aggregates in the form of fecal pellets. Lichens, mycorrhizal fungi, cyanobacteria and other microorganisms also contribute to aggregate formation and soil surface stabilization. The direct effects of rapid litter decomposition on infiltration and soil water storage in arid and semi-arid rangelands is generally negative: litter removal exposes the surface to raindrop impact, which leads to the formation of physical crusts, and increases evaporation from the soil surface. These negative impacts are balanced by the creation of surface-connected macropores and the incorporation of soil organic matter, resulting in the formation of stable aggregates.

}, keywords = {aggregate, ant, available water holding capacity, earthworm, fungi, hydrology, infiltration, invertebrate, rangeland, soil organic mattter, soil structure, soil water, termite}, url = {/files/bibliography/662.pdf}, author = {Jeffrey E. Herrick} } @conference {51219, title = {Simple method for reseeding of rills in degraded rangeland}, booktitle = {Annual Meeting, Society for Range Management}, year = {1998}, month = {1998}, abstract = {Traditional methods of reseeding degraded rangeland are expensive and frequently unsuccessful due to high rates of seed predation and seedling mortality. A method has been developed to increase the probability of seed germination and seedling establishment in {\textquotedblleft}safe sites{\textquotedblright}. Seeds are placed in three 1.3 cm-diameter x 10 cm pvc tubes. The small tubes are capped with crepe paper and glued inside of a 7.5 cm-diameter x 15 cm-long tube which. The large tubes are protected from seed predators with screens and chemical deterrent. The tubes are placed in small rills immediately above areas of high dispersion at the beginning of the rainy season. A small screen is placed 30 cm upstream from the tubes to deflect litter and sediment. Laboratory tests showed that the seeds are released within 15+2 seconds in artificial rills. In a series of preliminary field tests, seeds of sideoats grama (Bouteloua curtipendula) were deposited preferentially in microsites with relatively high levels of litter and grass cover at distances of up to at least 102 m down the rill from the seeder. Most seeds were deposited in lateral rills and not in the main channel.}, author = {Gutierrez Luna, R. and Jeffrey E. Herrick and G.B. Donart} } @article {51239, title = {Stable carbon and oxygen isotopes in Quaternary soil caronates as indicators of ecogeomorphic changes in the northern Chihuahuan Desert, USA}, journal = {Geoderma}, volume = {82}, year = {1998}, note = {//LOCAL//LTER-III//}, month = {1998}, pages = {137-172}, abstract = {

Stable carbon and oxygen isotopes in soil carbonates provide an additional technique for investigating Quaternary ecogeomorphic changes in arid and semiarid regions. This study presents d13C and d18O values in surface and buried soils in a Basin and Range region of southern New Mexico and west Texas. Three landform categories were investigated for their isotopic content: (1) middle piedmont slopes; (2) a lower piedmont slope and adjacent playa depressions; and (3) an intermontane basin floor. Soils of the middle piedmont slopes had greatest d13C variability, ranging from -0.6{\textperthousand} in buried soils to -11.1{\textperthousand} (PDB) in surface soils. Soils of the basin floor had greatest variability in d18O values, ranging from -0.6 {\textperthousand} to -7.6{\textperthousand} (PDB). Fossil pollen patterns roughly paralled d13C shifts, with Cheno-Am pollen exhibiting greatest changes. Both isotope and pollen data across stratigraphic discontinuities suggest that a conversion from C4 grasses to C3 desert shrubs accomopanied Holocene erosion. {\textcopyright} 1998 Elsevier Science B.V.

}, keywords = {article, articles, climate,paleoclimate, isotopes, stable, journal, journals, paleoclimate, paleosols, soil, paleoclimate, soil, paleosols, soil, pedogenic carbonates, soil, stable isotopes}, doi = {10.1016/S0016-7061(97)00100-6}, url = {files/bibliography/JRN00264.pdf}, author = {Curtis H. Monger and David R. Cole and Gish, J. W. and Giordano, T. H.} } @article {51244, title = {Seasonal changes in fractal landscape surface roughness estimated from airborne laser altimetry data}, journal = {International Journal of Remote Sensing}, volume = {19}, number = {13}, year = {1998}, note = {//USDA//NONE//}, month = {1998}, pages = {2509-2516}, abstract = {Fractal geometry is a useful tool for the analysis of landscape data. In this study fractal scaling was applied to high-resolution landscape data collected with a profiling laser altimeter. The objective of this work was to assess the persistence of scaling differences over time. Data were collected at the United States Department of Agriculture (USDA), Agriculture Research Service (ARS) Jornada Experimental Range in New Mexico, USA in May and September 1995 and February 1996 over a grass-dominated site, a shrub-dominated site, and a transitional area between shrub- and grass-dominated sites along four transects at each site for each data. Root-mean-square (RMS) roughness was scale-dependent and had more than one range of self-affine scaling. Different numbers of self-affine scaling intervals, boundaries of intervals, and fractal dimensions over these intervals were associated with different land covers. A linearity measure was applied to find intervals of fractal scaling. The number and boundaries of fractal scaling intervals appeared to be persistent over the year. Grass sand shrub sites had two and four linearity intervals respectively. The transitional site had a pattern of scaling that was intermediate between grass and shrub sites. The lowest fractal dimensions at small scales of 6-30 m corresponded to the maximum vegetation in September.}, keywords = {article, articles, fractal geometry, remote sensing, JORNEX, remote sensing, journal, journals, landscape, surface roughness, laser altimetry, surface roughness, remote sensing, airborne laser altimetry, remote sensing, fractal geometry, remote sensing, JORNEX, remote sensing, surface roughness, technique, airborne laser altimetry, technique, remote sensing, water balance, remote sensing}, author = {Y. Pachepsky and Jerry Ritchie} } @article {JRN54984, title = {Spatial Variability of Thermal and Near Infrared Imagery in JORNEX}, journal = {IEEE}, year = {1998}, pages = {589-591}, chapter = {589}, abstract = {

The JORNada EXperiment (JORNEX) held at the Jornada Experimental Range in southern New Mexico aims at the description of the surface energy balance of a desert grassland ecosystem. A large array of both field and remote sensing data have been collected from 1995 to 1998. Remote sensing data collected consists of visible and thermal infrared imagery, video imagery and laser profiler data. These data are being used to infer land surface characteristics such as surface temperature, albedo and roughness. These land surface characteristics can be used as input for surface energy balance models coupled with atmospheric models. However atmospheric models work with very coarse grid cells of at least 50*50 km. Remote sensing data typically has a geometrical resolution much smaller than 50*50 km. In addition to the scale discrepancy, surface energy balance models are generally non-linear algorithms, which amplifies scale problems. High resolution input data will not necessarily give the same results as low resolution input data. The problem arises of how to scale up the calculated surface energy balance fluxes to the much coarser resolution of the atmospheric model. The first step is to derive the length scales of the land surface characteristics involved in the calculation of the surface energy balance, therefore determining the maximum resolution required to sample the area. High resolution (~4m) NIR and TIR images with variogram and wavelet techniques will be used to study scaling.

}, url = {files/bibliography/Rango1998-08.pdf}, author = {Pelgrum, Henk and T. J. Schmugge and A. Rango and Jerry Ritchie and William P. Kustas} } @article {JRN54962, title = {Spatial Variability of Soil Heat Flux of a Single Honey Mesquite Dune in the Jornada Basin }, journal = {American Meteorlogical Society}, year = {1998}, pages = {262-263}, chapter = {262}, abstract = {

Spatial variation of soil properties has been of interest to a number of disciplines. Soil physicists have been interested in the spatial variation of properties affecting water transfer and compaction, while soil chemists have been interested in salinity and chemical properties. The reports in the literature on spatial studies are numerous and he reports on the scale of variation range from study to study and cover the range from a few centimeters o several meters.

}, url = {files/bibliography/Rango1998-04.pdf}, author = {J.H. Prueger and William P. Kustas and Lawrence E. Hipps and J. Hatfield and K. Ramalingam and A. Rango and Jerry Ritchie and Kris Havstad} } @article {51253, title = {The spatial distribution of termite activity in grazed and ungrazed Chihuahuan Desert grassland}, journal = {Journal of Arid Environments}, volume = {40}, year = {1998}, note = {//NMSU//NONE, LTER support//}, month = {1998}, pages = {77-89}, abstract = {

Termites are important in litter decomposition and nutrient cycling in desert grasslands but little isknown about the spatial distribution of termites and how spatial patterns are affected by topography and grazing by livestock. We measured the distribution of surface activity by the subterranean termite Gnathamitermes tubiformans in grazed and ungrazed Chihuahuan Desert grassland along 900 m transects that spanned a topographic gradient. Numbers of termite casts on litter and plants were recorded in 900 contiguous 1 m2 quadrats along a transect located in a grazed area and in an ungrazed control. Cover of plants and litter were also recorded in 1 m2 quadrats every 10 m along each transect.

}, keywords = {article, articles, Gnathamitermes, journal, journals, spatial scale, technique, spectral analysis, termite, activity, termite, gallery carton, termite, litter decomposition, termite, spatial variability, termites , SEE , topography, termites}, doi = {10.1006/jare.1998.0432}, url = {files/bibliography/JRN00265.pdf}, author = {Tracy, Keena N. and David M. Golden and Crist, Thomas O.} } @article {51261, title = {Seed-borne fungal endophytes on fourwing saltbush, Atriplex canescens }, journal = {Arid Soil Research and Rehabilitation}, volume = {11}, number = {4}, year = {1997}, month = {October 1, 1997}, pages = {307-314}, abstract = {

Fourwing saltbush, Atriplex canescens (Pursh) Nutt., produces copious quantities of small seed, with minimal nutrient reserves, protected in a hard porous capsule (utricle) that aids in dispersal. At germination, saprophytic fungi simultaneously colonize the utricle, testa, and root cortex cells of the emerging radicles. Seedling vigor was determined by measuring hypocotyl and radicle lengths after germination on minimal carbon or cellulose-supplemented medium. Comparisons were made between seedlings from utricle-excised and intact seed. Comparisons were also made between surface-sterilized and nonsterile excised seed. Minimal growth responses were observed in germinating seedlings from excised seeds on minimal carbon medium. Fungi, utricles, and cellulose supplementation positively affected seedling vigor. The results support a hypothesis that septate fungi recycle utricles and access organic carbon for seedling establishment.

}, keywords = {arid ecology, endophytic fungi, fertility, germination, land restoration, mutualism, mycorrhizae, native plants, plant nutrition, saprophytic fungi, symbiosis}, doi = {10.1080/15324989709381484}, url = {/files/bibliography/508.pdf}, author = {J.R. Barrow and Kris Havstad and Hubstenberger, J. and McCaslin, B D.} } @conference {51302, title = {Sensitive indicators of desertification: examples of tests in the Chihuahuan Desert}, booktitle = {International Symposium and Workshop on Combating Desertification: Connecting Science with Community Action}, year = {1997}, month = {May 12-16, 1997}, pages = {1}, address = {Tucson, AZ}, abstract = {Desertification is recognized as a suite of symptoms of degradation of rangelands. We selected a suite of indicators related to important ecosystem processes and tested these indicators at baseline sites with long, well-documented, histories of land management. Data were collected at grazing intensity gradients centered at livestock watering points, livestock exclosures, sites with documented change in vegetative cover and composition, and sites dominated by exotic species. Field measurements that provided the data for computing indicator metrics were collected at a site by a two-person team in less than 6 hours. Indicator metrics that proved to be sensitive to desertification provide calibration values of assessment and monitoring at sites where management and ecosystem status history are unknown. Indicators that were consistent and reliable include size and weighted skewness of unvegetated patches, spatial distribution and orientation of unvegetated patches, surface cover characteristics, total vegetative cover, shrub cover/grass cover, cover of native species/cover of exotic species, forage value index, and cover short-lived species/cover long-lived species.}, author = {A.G. de Soyza and Justin Van Zee and Walter G. Whitford} } @article {51303, title = {Sensitivity testing of indicators of ecosystem health}, journal = {Ecosystem Health}, volume = {3}, number = {1}, year = {1997}, month = {March 1997}, pages = {44-53}, abstract = {

The sensitivities of three indicators of ecosystem health were evaluated at several sites in the Jornada Basin of the Chihuahuan Desert. The size of bare patches, proportion of total grass cover contributed by long-lived perennial grasses and soil stability are interdependent indicators of ecosystem functions related to the retention and use of water and nutrients. Sensitivity tests were chosen using data collectedalong disturbance gradients and then tested using independent, ungrazed exclosures and adjacent grazed pastures. The mean size of bare soil patches was sensitive to anthropogenic disturbance. When bare soil patch data were transformed usiing natural logarithms, the skewness of the frequency distribution weighted by mean bare patch size could be used to indicate early disturbance to the ecosystem. The proportion of total vegetation that was long-lived also was sensitive to anthropogenic disturbance and appears to be a good indicator of ecosystem degradation. The slake test for soil surface stability was extremely sensitive to disturbance and may serve as an early-warning indicator of soil degradation for the coarse-textured soils which were evaluated.

}, doi = {10.1111/j.1526-0992.1997.00705.pp.x}, url = {/files/bibliography/509.pdf}, author = {A.G. de Soyza and Walter G. Whitford and Jeffrey E. Herrick} } @article {51281, title = {Shrub invasion and bacterial community pattern in Swedish pasture soil}, journal = {FEMS Microbiological Ecology}, volume = {24}, year = {1997}, note = {//OTHER//LTER III//}, month = {1997}, pages = {235-242}, abstract = {

In arid environments, soil resources accumulate around shrubs to form resource islands. These islands are accompanied by increased bacterial counts and/or increases in microbe mediated processes. The present study investigates the universality of resource islands by measuring bacterial numbers and soil nutrients under and between shrubs invading a Swedish pasture. Substrate utilization patterns were also compared. Neither bacterial count patterns nor soil nutrient measurements supported resource island formation. Analysis of the substrate utilization patterns indicated metabolic differences comparing under- and between-plant communities. The results of this study suggest that resource island formation is not an intrinsic property of shrub invasions but rather may be related to the water harvesting or hydraulic lift associated with shrubs in arid environments.

}, keywords = {article, articles, bacteria, food web, journal, journals, shrub invasion}, doi = {10.1016/S0168-6496(97)00060-3}, url = {files/bibliography/JRN00250.pdf}, author = {Peter Herman} } @article {51310, title = {Soil and sediments: Linkages to new research}, journal = {Bulletin of the Ecological Society of America}, volume = {78}, year = {1997}, note = {//??//LTER-III/}, month = {1997}, pages = {284-285}, abstract = {

Linkages to New Research The Scientific Committee on Problems of the Environment, SCOPE, convened a workshop sponsored by The Ministry of Agriculture, Natural Resources Management and Fisheries of The Netherlands and anonymous donors. The SCOPE Committee on Soil and Sediment Biodiversity and Eco system Functioning, chaired by Diana Wall Freckman, Colorado State Uni versity, USA and aided by co-chairs Margaret Palmer, University of Maryland, USA (Freshwater Sedi ments), Lijbert Brussaard, Agricul tural University, The Netherlands (Soils), and T. Henry Blackburn, Aarhus University, Denmark (Marine Sediments), met for the first work shop in late April 1997 in Wageningen, Holland. The 40 experts from 15 countries, representing tax onomists, ecologists, and biogeo chemists working in the domains of soils, freshwater sediments, and ma rine sediments, spent almost a week summarizing the status of knowledge on biodiversity in relation to func tioning in "their" ecosystems, and identifying similarities in taxa and functions and gaps in knowledge pre venting a synthesis across these do mains. SCOPE was the first integra tive workshop bringing together sci entists from these three domains and the first to emphasize the functional significance of specific organisms and taxa to ecosystem processes and the ecosystem services they represent.

}, keywords = {article, articles, journal, journals, sediment, soil, soil, sediment}, url = {files/bibliography/JRN00251.pdf}, author = {R. A. Virginia and D. W. Freckman} } @article {51311, title = {Stemflow contribution to the "fertile island" effect in creosotebush, Larrea tridentata}, journal = {Journal of Arid Environments}, volume = {35}, year = {1997}, month = {1997}, pages = {451-457}, abstract = {

Stemflow, throughfall and bulk precipitation were collected on six creosotebushes (Larrea tridentata) during 18 events in the summer rainy season in the northern Chihuahuan Desert. The average stemflow was 16{\textperiodcentered}8 {\textpm} 1{\textperiodcentered}9\%; throughfall averaged 64{\textperiodcentered}7 {\textpm} 3{\textperiodcentered}2\%. The concentration of all ions measured were significantly higher in stemflow than in the bulk precipitation. Total nitrogen, sulfate, and calcium concentrations were more than an order of magnitude higher in the stemflow than in the bulk precipitation. Concentration of ions in the upper 10 cm of soil were generally higher in soils under shrubs than in soils between shrubs. Measured quantities of ions in dry-fall were of sufficient magnitude to account for the increased concentration in stemflow water of most ions. Increases in nitrogen in stemflow water may be due to biological activity of stem crust micro-organisms in addition to dry-fall. Dry-fall that collects on the leaves and stems of this desert shrub may contribute to the {\textquoteleft}fertile island{\textquoteright} effect on the soils under the canopies of creosotebushes.

}, keywords = {bulk precipitation, creosotebush, dryfall, Larrea tridentata, soil fertility, stemflow, throughfall}, doi = {10.1006/jare.1996.0164}, url = {/files/bibliography/602.pdf}, author = {Walter G. Whitford and John P. Anderson and P.M. Rice} } @proceedings {51320, title = {Shrubland ecosystem dynamics in a changing environment}, year = {1996}, month = {1996}, keywords = {changing environment, dynamics, shrubland ecosystem}, isbn = {USDA Forest Service General Technical Report INT-GTR-338}, author = {J.R. Barrow and McArthur, E.D. and R. E. Sosebee and R. J. Tausch} } @article {51321, title = {Structure and function of C3 and C4 Chihuahuan Desert plant communities. Energy balance components}, journal = {Journal of Arid Environments}, volume = {34}, year = {1996}, month = {September 1,1996}, pages = {63-79}, abstract = {

During the past 150 years, the C3 shrubs creosotebush (Larrea tridentata (DC.) Cov.), mesquite (Prosopis glandulosa Torr. var. glandulosa), and tarbush (Flourensia cemua DC.) have invaded extensive areas of former C4 grasslands in deserts of the south-western United States. We measured energy balance components of these grass and shrub communities in the Chihuahuan Desert. Midday net radiation in the P. glandulosa community was about 20\% less than that in the others, where it was about equal. Midday soil heat flux was large in all communities and was greater in communities with small leaf areas. Midday and daily latent heat fluxes (or evapo-transpiration rates, ET) were about equal in all communities except the F. cernua community, where they were about 50\% greater due to greater leaf area and water supply. The fraction of ET made up of soil evaporation varied from 0{\textperiodcentered}3 to 0{\textperiodcentered}6 and was greater in L. tridentata and P. glandulosa communities. Differences of surface energy balance components of plant communities in this desert environment were generally small and were more related to surface characteristics (e.g. leaf area) and water supply than to photosynthetic pathway or vegetation type.

}, keywords = {Bouteloua eriopoda, desert grasslands, evapo-transpiration, Fluorensia cemua, Larrea trdientata, Pleuraphis mutica, prosopis glandulosa, shrub invasion, soil evaporation}, doi = {10.1006/jare.1996.0093}, url = {/files/bibliography/473.pdf}, author = {W.A. Dugas and Hicks, R.A. and Gibbens, Robert P.} } @article {51332, title = {Structure and function of C3 and C4 Chihuahuan Desert plant communities: Standing crop and leaf area index}, journal = {Journal of Arid Environments}, volume = {34}, number = {1}, year = {1996}, month = {September 1, 199}, pages = {47-62}, abstract = {

During the past 150 years, native C3 shrubs have invaded and dominated extensive areas of former C4 grasslands in deserts of the south-western United States. This vegetation shift has caused large changes in several aspects of the structure and function of these plant communities. To examine structural changes, we measured the standing crop of green herbaceous plants and live shrubs, leaf area index (LAI), and canopy cover and shrub density in grass and shrub plant communities that exist on sandy and clay soils in the Chihuahuan Desert. Standing crop ranged from 800 to 1800 kg ha-1 for grass communities and from 2800 to 3500 kg ha-1 for shrub communities. The LAI in grass communities was typically 0{\textperiodcentered}1 to 0{\textperiodcentered}2 and in shrub communities was 0{\textperiodcentered}3 to 0{\textperiodcentered}4. Averaged over the 2 years, the greatest LAI was in the shrub community on a clay soil that also had a herbaceous understory. Shrub canopy cover varied from 17\% (Flourensia cernua, tarbush) to 33\% (Prosopis glandulosa, honey mesquite). On sandy soils, this vegetation shift has resulted in a replacement of herbaceous vegetation with shrubs and a large reduction in species diversity, while on clay soils, due to greater soil fertility and soil water availability, there was only a slight decrease in herbaceous vegetation and little change in species diversity. This vegetation shift of desert grasslands has dramatically changed plant community structure.

}, keywords = {Bouteloua eriopoda, desert grasslands, Flourensia cernua, Larrea tridentata, Pleuraphis mutica, prosopis glandulosa, shrub invasion}, url = {/files/bibliography/483.pdf}, author = {Gibbens, Robert P. and Hicks, R.A. and W.A. Dugas} } @proceedings {51346, title = {Soil and vegetation indicators for assessment of rangeland ecological condition}, year = {1996}, month = {1996}, pages = {157-166}, publisher = {USDA, Forest and Range Experiment Station, General Technical Report RM-GTR-284}, address = {Mexico City, Mexico}, abstract = {

Indicators of rangeland ecological condition should be (1) quantitative, (2) rapid, (3) repeatable, (4) easily communicated, and (5) susceptible to sensitivity analysis. Most importantly, the indicators should be related to ecosystem function and to the capacity of the system to resist and recover from disturbance. Based on these criteria, we have developed a suite of indicators for North American desert rangelands. Most of these rangelands are located on fragile, nutrient- and organic matter-poor soils and suffer from periodic moisture deficits. Consequently, we have focused on indicators which reflect the capacity of the system to trap and retain soil and water resources. These indicators include size of bare soil patches, cryptogamic crust cover and soil surface stability, and the ratio of long-lived to short-lived perennials. Another suite of indicators reflect rangeland productivity. These include proportion of total perennial plant cover of species palatable to livestock as well as total biomass production. We have developed and tested these and a number of other indicators in a wide variety of plant communities with known disturbance histories at the Jornada Experimental Range in the Chihuahuan Desert in New Mexico, and validated them on cooler, more mesic rangelands in Idaho and Oregon, as well as an arid site in Utah. We will present results from the Chihuahuan Desert evaluation, together with a preliminary version of a variable-weighting system to combine these indicators into flexible indices of ecological condition which can be adapted to address the objectives of individual agencies and land managers.

}, url = {/files/bibliography/493.pdf}, author = {Jeffrey E. Herrick and Walter G. Whitford and A.G. de Soyza and Justin Van Zee}, editor = {Bravo, C.A.} } @proceedings {51350, title = {Shrublands and grasslands of the Jornada Long-Term Ecological Research Site: desertification and plant community structure in the northern Chihuahuan Desert}, volume = {Gen. Tech. Rep. INT-GTR-338}, year = {1996}, note = {//NMSU,USDA//LTER-III//ProCite field[6]: InProCite field[8]: Compilers}, month = {May 23-25, 1995}, pages = {48-50}, publisher = {U.S. Department of Agriculture, Forest Service, Intermountain Research Station}, address = {Las Cruces, NM}, abstract = {Semidesert grasslands of southern New Mexico have been replaced in this century with shrublands (chiefly creosote bush and mesquite). The Jornada Long-Term Ecological Research Program has been monitoring aboveground plant productivity, plant species composition, and other aspects of ecosystem function in 15 sites. Plant diversity differs significantly among vegetation types, with grasslands being the most diverse. Aboveground net primary productivity does not differ significantly among vegetation types. Productivity is correlated with plant species richness in some seasons; however, diversity has not been correlated with smaller fluctuation of production between years in the first few years of study. These results have implications for sustainable management of diversity and of productivity.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, desertification, plant community, diversity, plant community, productivity, plant community, structure, plant, diversity, plant, productivity, proceeding, proceedings}, author = {L. Huenneke}, editor = {J.R. Barrow and McArthur, E.D. and R. E. Sosebee and R. J. Tausch} } @article {51362, title = {Stemflow, throughfall and channelization of stemflow by roots in three Chihuahuan Desert shrubs}, journal = {Journal of Arid Environments}, volume = {32}, year = {1996}, month = {1996}, pages = {271-287}, abstract = {

Three studies were conducted to examine precipitation{\textendash}vegetation relationships in the multi{\textendash}stemmed shrubs Larrea tridentata, Prosopis glandulosa and Flourensia cernua in a desert ecosystem. We measured stemflow and throughfall as affected by bulk precipitation, canopy architecture and stem-angles. Using fluorescent dye, we traced root channelization of stemflow water. Stepwise regression analysis showed that the best one-variable model for stemflow in L. tridentata was canopy volume, which accounted for 87\% of variation. The best one-variable model for stemflow in P. glandulosa and F. cernua was canopy area, which accounted for 82\% of variation in both species. Stemflow data from winter and summer months were statistically compared to determine the influence of leaves on stemflow generation in P. glandulosa and F. cernua. Stemflow amounts collected during winter months do not differ significantly from those of summer months demonstrating that in these winter deciduous species the absence of leaves during winter months does not affect generation of stemflow. Analysis of variance showed that the percentage of throughfall was different among species suggesting that variations in canopy characteristics could explain, in part, these interspecific throughfall differences. Both stem-angle and stem-length had a significant effect on stemflow generation in F. cernua and L. tridentata, whereas there was only a significant relationship between stem-angle and stemflow in P. glandulosa. Analysis of rhodamine-B dye distribution under shrubs indicated that root channels are preferential pathways for movement of stemflow water into soil, and that this water is potentially the source of soil moisture which allows shrubs to remain physiologically active under drought conditions.

}, keywords = {Chihuahuan Desert, Flourensia cernua, Larrea tridentata, prosopis glandulosa, root channelization, stemflow, throughfall}, doi = {10.1006/jare.1996.0023}, url = {/files/bibliography/500.pdf}, author = {E. Martinez-Meza and Walter G. Whitford} } @article {51363, title = {Size decline in Larrea tridentata (creosotebush)}, journal = {The Southwestern Naturalist}, volume = {41}, number = {3}, year = {1996}, note = {//NMSU//LTER-III//}, month = {1996}, pages = {248-250}, abstract = {This study documents a dramatic decline in size of individuals within a Larrea tridentata population in southern New Mexico over a decade long period. It is most likely that the decline in size represents individual plants shrinking in size resulting from the death of shoot systems, especially the larger branches within these multi-stemmed shrubs. We suggest that the decline in size observed in our study area may be the intial stages of a more widespread phenomenon, driven by the desertification process taht accompanies the conversion of grasslands into shrublands.}, keywords = {article, articles, journal, journals, Larrea, population dynamics, plant, Larrea, plant, population dynamics, population dynamics, Larrea}, author = {Richard E. Miller and L. Huenneke} } @article {JRN54969, title = {Snow crystal imaging using scanning electron microscopy: I. Precipitated snow}, journal = {Hydrological Sciences}, volume = {41}, year = {1996}, month = {04/1996}, pages = {219-233}, chapter = {219}, abstract = {

Low-temperature scanning electron microscopy (SEM) was used to observe precipitated snow crystals. The newly-fallen snow
crystals were obtained in storms at Beltsville, Maryland, and at Bearden Mountain near Davis, West Virginia, USA. The snow samples were mounted on modified SEM stubs, frozen in liquid nitrogen, sputter coated with platinum, and imaged with an electron beam. Many types of precipitated snow crystals were observed including hexagonal plates, columns, needles, stellar dendrites, bullets, graupel, and rimed crystals. The SEM techniques that were developed can be used for quantitative measurements of size, shape and structure of crystals. SEM of precipitated snow appears to have direct application for the inference of atmospheric and cloud conditions where the snow crystals formed and travelled to the ground and for the development of a relationship between snow crystal type and snowfall intensity and amount. The SEM technique provides a new procedure to record permanently snow crystal conditions during winter storms.

}, url = {files/bibliography/Rango1996-03.pdf}, author = {A. Rango and W.P. Wergin and E. R. Erbe} } @article {JRN54981, title = {Snow crystal imaging using scanning electron microscopy: II. Metamorphosed snow}, journal = {Hydrological Sciences}, volume = {41}, year = {1996}, month = {10/1996}, pages = {235-250}, chapter = {235}, abstract = {

Low-temperature scanning electron microscopy (SEM) was used to observe metamorphosed snow crystals and grains obtained in the
field. Metamorphosed snow was obtained from seasonal snowpacks in the Colorado Rocky Mountains and in Alaska. The snow samples obtained in snowpits were mounted on modified SEM stubs, frozen in liquid nitrogen, transported in Dewar flasks to the SEM facility, sputter coated with platinum, and imaged with an electron beam. Analysis of a representative set of snow samples revealed examples of metamorphosed stellar crystals, fine snow grains with sintering, rounded and faceted crystals, several types of depth hoar, rounded grains of melt metamorphism, and an ice lens. Some of the crystals exhibiting both rounding and facets indicated that both
equitemperature and temperature gradient metamorphism influenced the snowpack. The SEM methods developed are operable in the field and can be used to quantify three-dimensionally size, shape and bonding characteristics of crystals. SEM appears to have direct application for better understanding of snow crystal metamorphism and snowpack processes, increasing knowledge of conditions leading to avalanche formation, and improving modelling of the transfer of microwave energy from the ground surface through the snowpack for eventual estimation of snow water equivalent.

}, url = {files/bibliography/Rango1996-05.pdf}, author = {A. Rango and W.P. Wergin and E. R. Erbe} } @article {JRN54985, title = {Spaceborne remote sensing for snow hydrology applications}, journal = {Hydrological Sciences}, volume = {41}, year = {1996}, month = {08/1996}, pages = {477-494}, chapter = {477}, abstract = {

Certain satellite-based remote sensing for snow hydrology applications has been very positive, namely, snow areal extent mapping
using visible and near-infrared sensors and snow water equivalent using passive microwave techniques. Although certain problems are yet to be solved, very specific applications have become operational. Data from the NOAA-AVHRR sensor are used to produce snow extent maps for about 4000 basins in North America and the data are distributed electronically by the NWS National Operational Hydrologie Remote Sensing Center. At the Canadian Climate Centre, a method has been developed for real time estimation of areal snow water equivalent over the Canadian prairies using microwave brightness temperatures, and the snow water equivalent maps are distributed to operational hydrological forecasters. Current research may also prove fruitful for estimates of snow wetness or active melting, snow albedo and snow grain size. It appears that forthcoming improvements in passive microwave spatial resolution should
increase the applicability of the data for snow hydrology. The spectral and spatial resolution of the visible/near-infrared data will also be
improved with the launch of EOS/MODIS. Combinations of sensors and integration with other types of data will further improve the suitability of spacebome data.

}, url = {files/bibliography/Rango1996-07.pdf}, author = {A. Rango} } @article {51370, title = {On the spatial pattern of soil nutrients in desert ecosystems}, journal = {Ecology}, volume = {77}, number = {2}, year = {1996}, note = {//NMSU, USDA//LTER III//}, month = {1996}, pages = {364-374}, abstract = {

We examined the spatial distribution of soil nutrients in desert ecosystems of the southwestern United States to test the hypothesis that the invasion of semiarid grasslands by desert shrubs is associated with the development of "islands of fertility" under shrubs. In grasslands of the Chihuahuan Desert of New Mexico, 35-76\% of the variation in soil N was found at distances \<20 cm, which may be due to local accumulations of soil N under Bouteloua eriopoda, a perennial bunchgrass. The remaining variance is found over distances extending to 7 m, which is unlikely to be related to nutrient cycling by grasses. In adjacent shrublands, in which Larrea tridentata has replaced these grasses over the last century, soil N is more concentrated under shrubs and autocorrelated over distances extending 1.0-3.0 m, similar to mean shrub size and reflecting local nutrient cycling by shrubs. A similar pattern was seen in the shrublands of the Mojave Desert of California. Soil PO4, Cl, SO4, and K also accumulate under desert shrubs, whereas Rb, Na, Li, Ca, Mg. and Sr are usually more concentrated in the intershrub spaces. Changes in the distribution of soil properties may be a useful index of desertification in arid and semiarid grasslands worldwide.

}, keywords = {Artemisia, nitrogen cycling, Artemisia, soil heterogeneity, article, articles, Bouteloua, nitrogen cycling, Bouteloua, soil heterogeneity, Bromus, nitrogen cycling, Bromus, soil heterogeneity, geostatistics, Great Basin Desert, Bouteloua community, Great Basin Desert, Larrea community, journal, journals, Larrea, nitrogen cycling, Larrea, soil heterogeneity, Mojave Desert, Larrea community, nitrogen cycling, phosphorous, soil heterogeneity, soil nutrients, soil, nitrogen, soil, phosphorus}, doi = {10.2307/2265615 }, url = {files/bibliography/JRN00213.pdf}, author = {W. H. Schlesinger and Raikes, Jane A. and Anne E. Hartley and Cross, Anne F.} } @article {51392, title = {Soils and sediments associated with remarkable, deeply penetrating roots of crucifiction thorn (Koeberlinia spinosa Zucc.)}, journal = {Journal of Arid Environments}, volume = {31}, number = {2}, year = {1995}, month = {October 1, 1995}, pages = {137-151}, abstract = {

Root systems of crucifixion thorn (Koeberlinia spinosa Zucc.) were excavated on an alluvial-fan toeslope in a desert area of southern New Mexico. Highcarbonate toeslope deposits of late Pleistocene age overlie low-carbonate middle Pleistocene deposits of an ancestral Rio Grande. These two deposits and their soils provide markedly different geomorphic, pedogenic, chemical and physical environments for the development of tap roots and their branches. Roots descended through the fan toeslope sediments and penetrated the river deposits to a depth of at least 5{\textperiodcentered}2m, much deeper than is usual for root penetration in this area. Remarkably, 2nd and 3rd order branches originated at depths of 2{\textperiodcentered}3 to 3{\textperiodcentered}8 m and grew vertically upward, branched profusely in the top 1 m of soil, and extended to within 10 cm of the soil surface. It is believed that occasional deeply penetrating soil water moves down channels once occupied by roots and other openings in the soil, and that this is a source of water for growth of the deeply penetrating roots, as well as for the roots that grow upward.

}, keywords = {buried soils, deeply penetrating soil water routes, desert soils, gypsum hardpan, root morphology, upward-growing roots}, doi = {10.1006/jare.1995.0056}, url = {/files/bibliography/444.pdf}, author = {L. H. Gile and Gibbens, Robert P. and J.M. Lenz} } @article {51391, title = {Supplement to the Desert Project Guidebook, with emphasis on soil micromorphology.}, year = {1995}, note = {//LOCAL, NMSU, USDA//LTER III//}, month = {1995}, edition = {Bulletin 142}, address = {Socorro, New Mexico}, abstract = {

This Supplement to the Desert Project Guidebook presents new study areas 23-27, and additional information for other study areas and thin section studies. New study area 23 is near pipline and power line roads that cross terraces and soils ranging in age from late Holocene to late middle Pleistocene. In area 23, morphology of the laminar, plugged, and adjacent horizons of an Argic Petrocalcid was related to the radiocarbon chronology of their carbonate. This pedon was the first so studied in the Desert Project and the first to be reported in the world literature on genesis of carbonate horizons.

Study area 24 illustrates a complex of Typic Haplocalcids and Argic Petrocalcids on a dissected landscape with ridge remnants of late middle Pleistocene age and the transition to a broad stable landscape of the same age dominated by Argie Petrocalcids. Area 24 illustrates a facies change from low-gravel to high-gravel materials and profound changes in carbonate morphology (stage III to IV) and soil classification (Typic Haplocalcid to Typic Petrocalcid) that accompany the facies change. Thin sections show evidence of dissolution of primary grains in the calcic horizon of the Haplocalcid.

Study area 25, in lce Canyon of the Organ Mountains, illustrates a bedrock-deserted ancient fan,and an Argie Ustic Petrocalcid dating from middle to early Pleistocene. This soil has a red, clay Bt horizon with a subhorizon that has more than 70\% clay,and illustrates stage IV of carbonate accumulation in soils of the mountain canyons. Thin sections show argillans on sand grains but not on ped faces. Prominent striae of oriented clay occur within peds and may represent former argillans.

Study area 26 is along and near the scarp of a middle Pleistocene relict basin floor that borders the Rio Grande valley. At area 26, the deep petrocalcic horizon of a Typic Petroargid illustrates stage IV of carbonate accumulation in low-gravel materials. Thin sections show evidence of disso-lution or primary grains in the petrocalcic horizon and accumulation of silica below it. Electron microscopy, soil column and culture studies indiate that soil microorganisms are involved in precipitation of fine-grain calcite in horizons of carbonate accmulation. Microscopic and chemical evidence indicates that palygorskite was neoformed in the petrocalcic horizon.

Study 27 is in a distinctive scarplet terrain in which the scarplets cut fan{\textbullet}piedmont sediments derived largely from sedimentary rocks such as limestone.\  The scarplets expose a Holocene Haplocalcid and the\  Bt horizon of an\  underlying\  Calciargid of late Pleistocene age.An argillic.horizon has not formed in high-carbonate parent materials or middle Holocene age, but has formed in the underlylng soil of late Pleistocene age. This suggests that moister climates of Pleistocene pluvials may have been involved in leaching the bulk of the carbonates so that the argillic horizon could form. Thin sections of the buried argillic horizon show both prominent argillans and some limestone grains. This shows that not all of the primary carbonate must be leached from the parent materials for an argillic horizon to form. Argillans were not found on limestone grains.

Photomicrographs illustrate illuvial clay and carbonate in soils that range in age from late Halocene to middle to early Pleistocene. Coatings of oriented clay on sand grains and pebnbles (grains argillans) are chracteristic of the Bt horizons. Grains argillans of many Bt horizons have been partly to completely obliterated by cabonate. Calcified root hairs, calcite filaments and framework grain coatings (calcitans) are the youngest forms of carbonate accumulation. They are currently forming and are the major morphological expression of carbonate in late Halocence soils. Progressively older carbonate forms increase in density and hardness with increasing carbonate content. Thin sections show evidence of dissolution of primary grains in soils of late-middle Pleistocene age and older.

}, keywords = {book, books, chapter, chapters, report, reports, soil, Desert Project, soil, micromorphology}, url = {files/bibliography/JRN00197.pdf}, author = {L. H. Gile and J. Hawley and R. Grossman and Curtis H. Monger and Montoya, C.E. and Greg H. Mack} } @article {51398, title = {Simple method for determination of mass loss rates for soil-contaminated samples in decomposition studies}, journal = {Pedobiologia}, volume = {39}, year = {1995}, note = {Full Article posted on this website with permission from Pedobiologia.}, month = {1995}, pages = {74-77}, abstract = {

The rate of weight loss is one of the most commonly cited parameters in litter decomposition studies. In spite of recent advances in the direct measurement of respiration rates, litter bags, litter standing crop measurements, and decomposition standards continue to be recommended as the most reliable methods for determining absolute decomposition rates (Anderson \& Ingram 1989). All three of these methods are frequently complicated by soil contamination. Three options are currently available to deal with this problem: (1) exclusion in the field with physical barriers, (2) mechanical separation in the laboratory, or (3) calculation based on the measurement of a constituent of the organic material, or of the soil. Soil can be at least partially excluded in the field by reducing the mesh size of litter bags. However, reducing mesh size may exacerbate other widely-recognized limitations of litter bags by excluding macroinvertebrates (Holter 1979), or by affecting microorganism populations through microclimate modification (St. John 1980).

}, keywords = {decomposition, litterbags, methods, moisture retention, roots, soil}, url = {/files/bibliography/448.pdf}, author = {Jeffrey E. Herrick} } @article {51402, title = {Soil physical property changes during dung decomposition in a tropical pasture}, journal = {Soil Science Society of America Journal}, volume = {59}, year = {1995}, month = {1995}, pages = {908-912}, abstract = {

The contributions of soil macroinvertebrates to the creation and maintenance of soil structure in tropical rangeland ecosystems are poorly understood, in spite of the fact that compaction is frequently cited as a limiting factor in pasture production. Decomposition of cattle dung (fecal material) is associated with high levels of soil macroinvertebrate activity. We hypothesized that bulk density and surface penetrometer resistance would be reduced in soil beneath decomposing cattle dung patches and that soil water infiltration capacity and drainable porosity would be increased. Cattle dung was deposited in patches during the dry and wet seasons of 1991 in a seasonally dry pasture located 5 km north of Caiias, Costa Rica, on a Typic Argiustoll. At the end of the wet season, surface 3-cm bulk density was \<0.93 Mg m-3 under dung patches, compared with 1.05 Mg m-3 \ in control plots. Drainable porosity, defined as air-filled porosity at 0.006 MPa, increased from 13\% in control plots to \>21\% under dung. Similar, but smaller, differences were recorded at dung patch edges and at a depth of 4 to 7 cm. At the end of the wet season, equilibrium infiltration rates averaged 71 mm h -1 in the patch plots and 34 mm h-1 \ in the controls. Changes in penetrometer resistance were transient and no treatment effects persisted to end of the wet season. The results of this study indicate that processes associated with dung decomposition play a role in reducing surface compaction.

}, doi = {10.2136/sssaj1995.03615995005900030040x}, url = {/files/bibliography/450.pdf}, author = {Jeffrey E. Herrick and R. (ed.) Lal} } @article {JRN54956, title = {Seasonal Runoff Forecasts for Hydropower Based on Remote Sensing }, journal = {Western Snow Conference 1995}, year = {1995}, month = {04/1995}, pages = {1-11}, chapter = {1}, abstract = {

In this study, the target of seasonal runoff forecasts for April through September is the inflow into the reservoir of the Swiss hydroelectric station at Sedrun and the river flow for the run-of-the-river station at Tavanasa. The catchments are situated in the Swiss Alps at 1300 - 3200 m a.s.l. so that snow is an important runoff factor. Snow reserves on 1 April can be reconstituted from satellite snow cover monitoring during the snowmelt period. In real time, point measurements of the snow water equivalent on 31 March serve as indices to select a snow cover of a past year evaluated from monitoring. Based on snow reserves and expected precipitation, monthly runoff volumes are forecasted on 31 March and updated after satellite overflights. Errors in 1993 and 1994 resulted from unusually warm temperature and heavy rainfalls at the end of the snow melt season in September. More reliable forecasts improve hydropower generation and help to achieve better prices on the electricity market.

}, url = {files/bibliography/Rango1995-01.pdf}, author = {J. Martinec and A. Rango} } @article {51417, title = {Subterranean termites: regulators of soil organic matter in the Chihuahuan Desert}, journal = {Biology and Fertility of Soils}, volume = {19}, year = {1995}, note = {//NMSU//LTER III//}, month = {1995}, pages = {15-18}, abstract = {

Soil organic matter and the abundance of subterranean termites were measured at 89 locations spaced at 30-m intervals from the bottom to the top of a small desert watershed. There was no correlation between soil organic matter content and topographic position on the watershed. Analysis by autocorrelogram demonstrated that the soil organic matter content was randomly distributed on the watershed. There was a highly significant negative correlation between termite abundance and soil organic matter, r = -0.97. Soils characterized by horizon in soil pits within each vegetation type (soil type) showed some relationships to erosion-deposition areas on the watershed, with surface organic matter contents varying between 3.4\% in the playa basin where termites were absent to 0.4\% in a sparse shrubland on erosional soils. In the northern Chihuahuan Desert, subterranean termites appear to be responsible for most of the variation in soil organic matter.

}, keywords = {article, articles, decomposition, belowground, decomposition, termites, journal, journals, soil, organic matter turnover, termite, soil organic matter, transect, soil organic matter, transect, termites}, doi = {10.1007/BF00336340}, url = {files/bibliography/JRN00196.pdf}, author = {M. H. Nash and Walter G. Whitford} } @article {JRN54832, title = {State and transition models for rangelands. 2. Ecology as a basis for rangeland management: Performance criteria for testing models.}, journal = {Tropical Grasslands}, volume = {28}, year = {1994}, month = {1994}, pages = {206-213}, chapter = {206}, abstract = {

The \ objectives \ of \ this \ paper \ are \ to: \ propose criteria for testing the applicability of models for rangeland management; and test 2 competing models using those criteria. Predicting change accurately, detecting change, relevance to management and facilitating communication are the performance criteria. Competing models are the range condition model derived from Clement- sian ecology and the state and transition \ model based on \ non-equilibrium \ ecology. The ability of competing models to predict ecosystem change is assessed in terms of ecosystem organising processes and attributes \ such as competition, resistance and resilience, temporal thresholds and feedback. The ability to detect change is viewed in terms of detection at the community and land- scape scales. Relevance to management and com- munication are assessed within the context of effectively communicating the effects of manage- ment decisions on ecosystem processes to both traditional \ and non-traditional decision makers and a larger public constituency. \ Although \ the state and transition model is the most acceptable of the 2 competing models based on the criteria, improvements \ are needed. Most notable \ is the need for a spatial component in the application of the model for management purposes, and the need for attention to improved communication with a wide range of \ resource \ users.

}, keywords = {ecology, Performance criteria, rangeland management, rangelands, state and transition models, testing models.}, url = {https://www.tropicalgrasslands.asn.au/Tropical\%20Grasslands\%20Journal\%20archive/PDFs/Vol_28_1994/Vol_28_04_94_pp206_213.pdf}, author = {Joel R. Brown} } @article {51440, title = {Secondary chemistry of the leaf surface of Flourensia cernua}, journal = {Biochemical Systematics and Ecology}, volume = {22}, number = {1}, year = {1994}, month = {1994}, pages = {73-77}, abstract = {

Epicuticular wax accounted for 9.2\% fo the dry weight of whole Flourensia cernua (tarbush) leaves. Leaf surface extracts of tarbush were analyzed for mono- and sesquieterpenoids with gas chromatography/mass spectrometry. Camphene, $\#$ mycrene, 3-carene, limonene, 1,8-cineole, borneol, cis jasmone, $\#$ caryphyllene, caryophyllene oxide and globulol were consistently present in tarbush. Concentrations of several unidentififed compunds were estimated. A great deal of plant to plant variability was detected in leaf surface mono= and sesquietepenoid concentration. Infomation obtained on surface chemistry might be exploited to enhance use of tarbush as a forage for domestic herbivores.

}, keywords = {epicuticular waxes, Flourensia cernua, leaf surface chemistry, monoterpenoids, sesquiterpenoids}, doi = {10.1016/0305-1978(94)90116-3}, url = {/files/bibliography/419.pdf}, author = {Richard E. Estell and Kris Havstad and E.L. Fredrickson and Gardea-Torresdey, J.L.} } @article {51447, title = {Sheep grazing as a range improvement tool}, journal = {Sheep Research Journal}, volume = {10}, number = {1}, year = {1994}, month = {1994}, pages = {72-78}, abstract = {Grazing is an integral and natural process on rangelands. Long term studies have concluded that grazing can be managed to manipulate the vegetative composition of rangelands. There are tow principle criteria that must be implemnted to achieve improvement. First, grazing must be managed by established goals and realistic specific objectives. Without achievable goals and clearly stated objectives grazing would be unmanaged and extensive experiences have illustrated thta unmanaged grazing by domestic and wild herbivores can result in catastrophe. Basic principles for establishing these golas and objectives are well documented. Second, improvement should be defined as attaining desired objectives for the rangeland resource. In some instances, improvement will wquate with increased forage available for grazing livestock. In other instances, improvement will be based on non livestock forage criteria. In all cases the resource will be benefitted and livestock will maintain an intergral role in the renewable use and sustained management of rangelands.}, url = {/files/bibliography/425.pdf}, author = {Kris Havstad} } @article {51450, title = {Soil water and soils at soil water sites, Jornada Experimental Range}, volume = {Soil Survey Investigations Report 44}, year = {1994}, month = {1994}, pages = {iii-592}, institution = {USDA, Soil Conservation Service}, url = {/files/bibliography/429.pdf}, author = {C.H. Herbel and L. H. Gile and E.L. Fredrickson and Gibbens, Robert P.}, editor = {L. H. Gile and R. J. eds. Ahrens} } @article {51452, title = {Seasonal and spatial population dynamics of the nitrogen-efficient guild in a desert bajada grassland}, journal = {Applied and Environmental Microbiology}, volume = {60}, number = {4}, year = {1994}, note = {//NMSU//LTER-III//}, month = {1994}, pages = {1160-1165}, abstract = {

This study examined the temporal and spatial variation in the populations of bacteria from a Chihuahuan desert bajada grassland that could grow on nearly nitrogen-free medium, a nitrogen-efficient guild (NEG). A Curtis similarity index of 0.876 and nearly identical diversity and equability indexes (H{\textquoteright} = 1.22, J = 0.46 and H{\textquoteright} = 1.27, J = 0.48 for the crown edge and interplant samples, respectively) indicated that there was no qualitative difference between the NEG assemblages isolated from samples taken at Bouteloua eriopoda plant crowns and in nonvegetated areas 45 cm from crowns. The difference in NEG populations between the crown and interplant samples was only 2-fold, despite a 9.5-fold difference in root biomass between the sites. These differences, while consistent, were statistically significant at only 50\% of the sampling times. there was over an order of magnitude difference in NEG numbers in root-associated soil and in bulk soil from the crown or intercrown sites. The typical trend for temporal variation in NEG numbers was that they increased in the spring, fluctuated dramatically over the summer, and declined at the summer{\textquoteright}s end. The pattern of soil moisture change was the only abiotic variable which showed the same fluctuation pattern as NEG numbers.

}, keywords = {article, articles, bacteria, heterotrophs, bacteria, nitrogen-efficient guild, grassland, bacteria, journal, journals}, url = {files/bibliography/JRN00179.pdf}, author = {Peter Herman and Kerri R. Provencio and Ruben Torrez and Seager, Gwen M.} } @article {51456, title = {A simulation experiment to quantify spatial heterogeneity in categorical maps}, journal = {Ecology}, volume = {75}, number = {8}, year = {1994}, note = {//OTHER//LTER III//}, month = {1994}, pages = {2446-2455}, abstract = {

Spatial heterogeneity (SH) is generally defined as the complexity and variability of a system property (e.g., plant biomass, cover) in space. Despite its importance in both theoretical and applied ecology, a formal and rigorous definition of SH is lacking. Such a definition is needed to facilitate quantitative analyses. To this end, we suggest that SH must be defined in terms of its underlying components. For categorical maps, SH is the complexity in five components: (1) number of patch types, (2) proportion of each type, (3) spatial arrangement of patches, (4) patch shape, and (5) contrast between neighboring patches. To illustrate the use of these components to develop a quantitative definition of SH, we used statistical models to produce categorical maps with known underlying SH characteristics. These simulated maps were analyzed in a factorial experiment to examine the effectiveness and sensitivity of four indices (i.e., fractal, contagion, evenness, patchiness) to detect patterns in these underlying components of SH. Our results show that any definition of SH is strongly dependent on the underlying variables and the methods used, that many indices depict different aspects of SH, that significant interactions exist among the five components of SH, and that some indices are strongly correlated. Quantification of spatial heterogeneity is essential to our understanding of the relationships between spatial heterogeneity and landscape functions and processes. However, all techniques to measure SH must be evaluated against systems with known characteristics of SH. Such a system is developed and used in this study.

}, keywords = {article, articles, journal, journals, model, landscape index, model, spatial heterogeneity, spatial heterogeneity, model}, doi = {10.2307/1940898 }, url = {files/bibliography/JRN00173.pdf}, author = {Harbin Li and J. F. Reynolds} } @mastersthesis {51459, title = {Stemflow, throughfall, and root water channelization by three arid land shrubs in southern New Mexico}, year = {1994}, note = {//NMSU, USDA//NONE, LTER//}, month = {1994}, pages = {81}, school = {New Mexico State University}, type = {M.S. Thesis}, address = {Las Cruces, New Mexico}, abstract = {Three experiments were conducted to examine how precipitation-vegetation ralationships for the shrubs Larrea tridentata, Prosopis glandulosa, and Flourensia cernua affect the interception, redistribution, and storage of water in desert ecosystem. The first experiment was designed to determine the percentage of rainfall partitioned as stemflow and throughfall, and also to evalute the effect of some plant conopy parameters on stemflow and throughfall. The second examined the effect of stem-angles on stemflow. The third assessed the effect of varying canopy areas and volumes as well as root allocation on redistribution of stemflow into the soil profile.... Analysis of rhodamine-B dye distribution under shrubs indicated that root channels are preferential pathways for movement of stemflow water into soil, and that this water is potentially the source of soil moisture which allows shrubs to persist and even prosper under drought conditions.}, keywords = {dissertation, dissertations, Flourensia, stemflow, Flourensia, throughfall, Flourensia,root water channeling, hydrology, root water, Larrea, stemflow, Larrea, throughfall, Larrea,root water channeling, Prosopis, stemflow, Prosopis, throughfall, Prosopis,root water channeling, shrub, stemflow, shrub, throughfall, stemflow, shrub, theses, thesis, throughfall, shrub}, author = {E. Martinez-Meza} } @article {51472, title = {Sex-biased herbivory in Ephedra trifurca: the importance of sex-by environment interactions}, journal = {Oecologia}, volume = {96}, year = {1993}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1993}, pages = {49-55}, abstract = {We examined patterns of herbivory in the dioecious desert shrub, Ephedra trifurca (Ephedraceae), along a small watershed in the northern Chihuahuan Desert. We documented significant (p= 0.002) sexual dimorphism in densities of Lasioptera ephedrae and L. ephedricola (Diptera: Cecidomyiidae), with male E. trifurca supporting higher densities than did females. Densities of gall midges varied significantly (p< 0.001) among four sample populations of E. trifurca arrayed along the watershed and exhibited an inverse gradient with elevation. There was also a significant (p= 0.006) sex-by-site interaction such that the degree of intersexual variation in gall densities decreased down the watershed. Variation in gall densities and intersexual variation in gall densities exhibited inverse trends with variation in soil water and in inorganic nitrogen concentrations along the watershed.}, keywords = {article, articles, Ephedra,herbivory, grazing,Ephedra, herbivory,Ephedra, journal, journals, plant,Ephedra}, author = {Boecklen, W. J. and Hoffman, M. T.} } @article {51495, title = {Soil-geomorphic and Paleoclimatic Characteristics of the Fort Bliss Maneveur Areas, Southern New Mexico and Western Texas}, year = {1993}, note = {//OTHER//NONE//}, month = {1993}, institution = {Cultural Resources Branch, Environmental Management Division, Directorate of Environment, U.S. Army Air Defense Artillery Center}, address = {Fort Bliss, Texas}, abstract = { By the early Quaternary period (2 million years ago) the ancestral Rio Grande had spilled through Fillmore Pass between the Organ and Franklin Mountains and was filling the Hueco Bolson with river sediments (Hawley et al., 1969). By middle Pleistocene, when the ancestral Rio Grande entrenched into its modern valley (400 to 300 ka, Gile et al., 1981), it had been diverted back to the west of the Franklin Mountains, probably as the result of uplifting of the Organ-Franklin Mountain chain (Seager 1981). Since the mid-Pleistocene, landscape evolution on Fort Bliss has been restricted mainly to (1) alluvial fan deposition, (2) land displacement along faults, and (3) eolian activity. Alluvial fan depositon has invlolved at least four generations of alluvial fans on the piedmont aprons that skirt the mountains. The fans range in age from approximately 400 ka to the present arroyo mouth deposits. Land displacment along faults has occurred throughout the late Pleistocene and Holocene. Sediments that fill linear depresson caused by extensional faulting are the result of both tectonic movement and climatically driven sedimentiation that presumably corresponds to periods of aridity. Eolian activity has modified existing soil strata in areas that were not sheltered from wind erosion by desert pavement, vegetation, or younger deposits. Most of the soilscape on Fort Bliss has experienced multiple periods of deflation and reburial by locally derived eolian sediments. There are at least four eolian deposits in the basin floor that range in age from early Holocene to Historical blowsand deposits.}, keywords = {book, books, chapter, chapters, climate,paleoclimate, geomorphology, carbonates, paleoclimate, pollen,fossil, report, reports}, isbn = {Historic and Natural Resources Report No. 10}, author = {Curtis H. Monger} } @article {51499, title = {Satellite assessment of drought impact on native plant communities of southeastern New Mexico, USA}, journal = {Journal of Arid Environments}, volume = {24}, number = {3}, year = {1993}, month = {April 1, 1993}, pages = {305-319}, abstract = {

Low spatial resolution imagery from a polar orbiting meteorological satellite was utilized to detect short-term drought effects on native plant communities in southeastern New Mexico, U.S.A. rangelands. A spectrally derived Vegetation Index was compared to the Palmer Drought Severity Index Crop Moisture Index, and monthly precipitation departures for a wet year (1988) and a dry year (1989). Differences between years as well as between plant communities were assessed. Plant communities consisting primarily of grass species were the most spectrally responsive to variation in precipitation, while forested areas were least affected.

}, doi = {10.1006/jare.1993.1027}, url = {/files/bibliography/408.pdf}, author = {Peters, A.J. and Reed, B.C. and M.D. Eve and Kris Havstad} } @proceedings {51500, title = {Sustainable livestock grazing in New Mexico}, volume = {2}, year = {1993}, month = {1993}, pages = {847-854}, abstract = {

For decades, the impact of domestic livestock grazing on rangelands in the Southwest has been debated by scientists, land administrators, ranchers, those with environmental concerns, and others, but the debate has become more focused In recent years. The important ecological \ questions related to grazing impacts are difficult to address because they require long-term studies and lack the control necessary to isolate the influence of different environmental \ factors. This paper is based on three relatively long-term data sets, two from desert grassland in southern New Mexico (the New Mexico State University College Ranch and the Jomada Experimental Range) and one from shortgrass vegetation in south-central New Mexico (Fort Stanton). These data indicate that herbage production varied over the years under conservative cattle grazing, but exhibited no obvious downward trend for periods approaching 50 years. Herbage production declined during drought, while responding to favorable precipitation following droughts. These studies indicate that moderate cattle grazing In the Southwest is sustainable and that climate often exerts a controlling influence that can obscure other environmental influences.

}, url = {/files/bibliography/409.pdf}, author = {Pieper, Rex D. and Reldon F. Beck and Gibbens, Robert P. and G.B. Donart} } @article {51535, title = {A simple model for predicting soil temperatures in desert ecosystems}, journal = {Soil Science}, volume = {153}, number = {4}, year = {1992}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1992}, pages = {280-287}, abstract = {We present a model for predicting soil temperatures in arid regions using current above surface conditions (temperature or temperature and solar radiation) and the annual sinusoidal behavior of temperature in the deeper soil profile. The model is based on that of Parton (Parton, W.J. 1984. Soil Sci. 139:93-101) and provides considerable temperature detail with a daily time step: maximum, minimum, and mean temperature at any depth; hourly temperature detail if desired. The error in predicted temperatures is about the same as those in models that require soil temperature inputs from at least one depth. This model, however, can be used for predicting soil temperatures in arid sites for which there are no soil temperature data or for predicting soil temperatures under future climates or environmental conditions.}, keywords = {article, articles, journal, journals, model, Parton, model, soil temperature, soil temperature, predicting}, author = {P. R. Kemp and Joe M. Cornelius and J. F. Reynolds} } @article {51540, title = {Spatial aggregation and neutral models in fractal landscapes}, journal = {The American Naturalist}, volume = {139}, number = {1}, year = {1992}, note = {//OTHER//LTER Sevilleta//}, month = {1992}, pages = {32-57}, abstract = {

Fragmented landscaped after ecological interactions by modifying the flux of organism, material, and energy. Fragmented distributions of hypothetical resources and species were represented by several models of landscape patterns at scales ranging from 90 to 2,400 m. Maps of resource aggregations at three scales resulted in multiple-scale notions of "patch,""gap,""edge,""corridor,""source," and "sink." A neutral model of species co-occurrence was developed for analyses conducted at several scales. The neutral model has implications for sampling mutualistic species and for detecting species{\textquoteright} responses to changes in environmental conditions. An ecologically meaningful view of landscape pattern depends on the home range size, dispersal ability, or speed with which organisms use resources rather than on the cartographic depiction of the landscape used by humans.

}, keywords = {article, articles, fractal landscapes, journal, journals, landscape, ecology, model,neutral, model,spatial aggregation}, doi = {10.1086/285312}, url = {files/bibliography/JRN00162.pdf}, author = {Milne, Bruce T.} } @article {51548, title = {Soil biota and soil properties associated with surface rooting zone of mesquite (Prosopis glandulosa) in historical and recently desertified Chihuahuan Desert habitats}, journal = {Biology and Fertility of Soils}, volume = {14}, year = {1992}, note = {//NMSU, USDA//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1992}, pages = {90-98}, abstract = {

The woody legume, mesquite (Prosopis glandulosa) has expanded from its historical habitats (playas and arroyos) to recently occupied grassland and dune habitats during the desertification of perennial grasslands in the Chihuahuan Desert. We studied historical and recently occupied sites, having hypothesized that the trophic structure and population density of soil microarthropods and nematodes associated with the surface root system of mesquite would differ in sites representing historical and recent habitats, and that the N mineralization potential would be lower in the recent habitats. Our results showed that net N mineralization potential did not differ significantly among the sites, even though soil nutrient concentrations and texture varied widely. Concentrations of organic C, N, and P were lowest in the recent dune habitat and highest at the playa. Very low concentrations of P in the dune and grassland soils implicated P as a limiting factor in these systems. The bacterial-feeding and omnivore-predator functional groups made up the largest fraction of the nematode community at most of the sites. The high density of plant-feeding nematodes at the playa indicated that herbivory is potentially most important at this site. Total microarthropod densities did not vary significantly among habitats, with Collembola densities highest in the mesquite dunes. Grazers were the dominant microarthropod functional group. While both C and N pool sizes were higher in the historical habitats, a higher substrate lability in the recent habitats appeared to support biota populations and N mineralization rates equivalent to those in the playa and arroyo. Differences in soil properties and biota among historical and recent mesquite habitats may be important for understanding the changes that have occurred in Chihuahuan Desert ecosystems during desertification.

}, keywords = {article, articles, collembola, community,Prosopis, desertification, journal, journals, microarthropod,Prosopis soils, nematode, nitrogen mineralization, nutrients, nitrogen mineralization, Prosopis, Prosopis, soil biota, Prosopis,rooting zone, Prosopis,soil properties, soil properties}, doi = {10.1007/BF00336256}, url = {files/bibliography/92-Biol\&FertofSoils-Whitford.pdf}, author = {R. A. Virginia and W. M. Jarrell and Walter G. Whitford and D. W. Freckman} } @article {51557, title = {Sediment-related transport of nutrients from southwestern watersheds}, journal = {Journal of Irrigation and Drainage}, volume = {117}, number = {5}, year = {1991}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1991}, pages = {736-747}, abstract = {

Data from rainfall simulation experiments conducted in Arizona and New Mexico were used to identify relationships between total suspended sediment (TSS) concentrations (kg/ha/mm of runoff) in runoff and concentrations (kg/ha/mm of runoff) of total phosphorus (TP), total volatile suspended sediment (TVSS), and total nitrogen (TN). The units of kg/ha/mm of runoff are equivalent to mg/l divided by 100. Data were collected from pinyon-juniper, ponderosa pine, short grass prairie, creosote bush, and bottomland vegetation types. Lumping data from these five vegetation types yielded a relationlship for total phosphorus of TP = 0.0013(TSS)0.83 with a linear correlation coefficient of r = 0.77. The relationship for total volatile suspended sediment was TVSS = 0.274(TSS)0.72 (r = 0.91). A poor relationship was found for total nitrogen with TN = 0.008(TSS)0.15 (with r = 0.11). These relationships were validated using data from other rainfall simulation experiments and naturally occurring ephemeral streamflow in southern New Mexico.

}, keywords = {article, articles, hydrology, nutrients, hydrology, sediment transport, journal, journals, nitrogen, hydrology, nutrients, hydrology, nutrients, hydrology,runoff, phosphorus, hydrology, phosphorus,runoff, rainfall simulation,hydrology, runoff, SEE }, doi = {10.1061/(asce)0733-9437(1991)117:5(736)}, url = {files/bibliography/JRN00140.pdf}, author = {S. M. Bolton and Timothy J. Ward and R. A. Cole} } @article {51565, title = {Some effects of precipitation patterns on mesa dropseed phenology}, journal = {Journal of Range Management}, volume = {44}, number = {1}, year = {1991}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {January 1, 1991}, pages = {86-90}, abstract = {

Phenology of mesa dropseed [Sporobolus flexuosus (Thurb.) Rydb.] was studied from 1979 to 1987 on the Jornada Experimental Range in southern New Mexico. Growing season (March through November) precipitation ranged from 99 to 308 mm during the 8-year period. Foliage height and number of leaves were recorded weekly for individually marked culms on 20 plants. New culms usually appeared during the first week in March and green leaf tissue often persisted until the end of November. Correlation analyses of accumulated weekly height increments and accumulated weekly precipitation showed that growth was highly dependent upon rainfall (r = 0.81 to 0.97). Leaf formation was also correlated with rainfall (r = 0. 79 to 0.98). Even in relatively wet years there were 1 or 2 periods of no growth. In drier years, no growth periods totaled as much as 87 days. Periods of rapid growth occurred only after rainfall events \> 13 mm. The first exsertion of seed heads occurred as early as the last week of July and as late as the second week of October. The temporal plasticity of mesa dropseed phenology indicates that it is well adapted to the arid environment.

}, keywords = {arid zones, Chihuahuan Desert, grass growth, leaf development, rangeland, Sporobolus flexuosus}, doi = {10.2307/4002646 }, url = {/files/bibliography/367.pdf}, author = {Gibbens, Robert P.} } @article {51568, title = {Sample size determinations for studying selected cattle foraging behaviors}, journal = {Applied Animal Behavior Science}, volume = {30}, number = {1}, year = {1991}, note = {Reprinted with permission from Elsevier, Copyright {\textcopyright} 1991. (http://www.sciencedirect.com/science/journal/01681591)}, month = {1991}, pages = {17-26}, abstract = {

Experimentation on livestock foraging behaviors under free-ranging conditions is frequently constrained by few experimental units (animals). Effective research designs require knowledge of expected sampling variability, but this information relative to range foraging behaviors is lacking. Sixteen 5-year-old range beef cows were used to estimate daily grazing time (DGT) and fecal output (percentage of body weight, FOBW) for 46 consecutive days during a winter grazing season. Estimates of components of variability associated with cows, days, and theoretical treatment effects were constructed from these data. Implied sample size requirements for a half-confidence-width =10\% of the mean and a Type 1 significance level of 0.05 were 7 and 9 cows for DGT and FOBW, respectively, with day as a fixed effect. For day as a random effect, implied sample sizes were 5 days and 5 animals for DGT, and 5 days and 9 animals for FOBW. Variability among animals was greater when estimating FOBW than for DGT estimates. Detecting differences between two treatments sampled over 5 days with Type 1 and Type 2 probabilities of 0.05 and 0.10, respectively, implied sample sizes of five and \> 20 cows for DGT and FOBW estimates, respectively. In general, these data indicated that \<5 animals was insufficient and \> 20 was excessive. These sample size estimates were obtained from a relatively uniform set of animals grazing a uniform quality and quantity of forage. Estimates of N would have been greater under more variable experimental conditions. Given constraints of statistics and the logistics of range nutrition experimentation, unless sample size requirements can be satisfied it may not be appropriate to examine certain questions with current experimental methodologies.

}, doi = {10.1016/0168-1591(91)90081-8}, url = {/files/bibliography/369.pdf}, author = {Kris Havstad and K. M. Olson-Rutz} } @article {51570, title = {The second Las Cruces trench experiment: Experimental results and two-dimensional flow predictions}, journal = {Water Resources Research}, volume = {27}, number = {10}, year = {1991}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1991}, pages = {2707-2718}, abstract = {

As part of a comprehensive field study designed to proved data to test stochastic and deterministic models of water flow and contaminant transport in the vadose zone, several trench experiments were performed int eh semiarid region of southern New Mexico. The first trench experiment is discussed by Wierenga et al. (this issue). During the second trench experiment, a 1.2 m wide by 12 m long area on the north side of and parallel to a 26.4 m long by 4.8 m wide by 6 m deep trench was irrigated with water containing tracers using a carefully controlled drip irrigation system. The irrigated areas was heavily instrumented with tensiometers and neutron probe access tubes to monitor water movement, and with suction samplers to monitor solute transport. Water containing tritium and bromide was applied during the first 11.5 days of the study. Thereafter, water was applied without tracers for and additional 64 days. Both water movement and tracer movement were monitored in the subsoil during infiltrations and redistribution. The experimental results indicate that water and bromide moved fairly uniformly during infiltration and the bromide moved ahead of the tritium due to anion exclusion during redistribution. Comparisons between measurements and predictions made with a two-dimensional model show qualitative agreement for two of the three water content measurement planes. Model predictions of tritium and bromide transport were not as satisfactory. Measurements of both tritium and bromide show localized areas of high relative concentrations and a large downward motion of bromide relative to tritium during redistribution. While the simple deterministic model does show larger downward motions for bromide than for tritium during redistribution, it does no predict the high concentrations of solute observed during infiltration, nor can it predict the heterogeneous behavior observed for tritium during infiltration and for bromide during redistribution.

}, keywords = {article, articles, journal, journals, model, contaminant transport, model, water flow, trench experiment, water flow, model}, doi = {10.1029/91WR01538}, url = {files/bibliography/JRN00145.pdf}, author = {Hills, R. G. and Peter J. Wierenga and D. B. Hudson and Kirkland, M. R.} } @mastersthesis {51576, title = {Seasonal diet quality, intake, and fecal output estimates of steers grazing semidesert rangeland}, year = {1991}, note = {//??//NONE//}, month = {1991}, school = {New Mexico State University}, type = {M.S. Thesis}, address = {Las Cruces, New Mexico}, keywords = {cattle grazing,diet, dissertation, dissertations, theses, thesis}, author = {D. King} } @article {51598, title = {Subterranean termites and long-term productivity of desert rangelands}, journal = {Sociobiology}, volume = {19}, number = {1}, year = {1991}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1991}, pages = {235-243}, abstract = {

Studies of soil properties, growth and species composition of vegetation, hydrology and patterns of organic matter removal were made on plots where termites had been eliminated and on plots with subterranean termites present. Subterranean termites affected all of the parameters measured. There was a negative correlation between termite abundance/activity and soil organic matter. Soils of termite free plots have lower infiltration and water storage but higher soil nitrogen. These soil properties have an effect on the species composition and productivity vegetation. The importance of subterranean termites as effectors of soil properties and vegetation suggests that these animals are key consumers in desert rangelands.

}, keywords = {article, articles, decomposition, termites, hydrology, infiltration, termites, journal, journals, pesticide, Chlordane, rangeland,productivity,termites, termite, soil organic matter, termite,decomposition, termite,productivity, termites, infiltration}, url = {files/bibliography/JRN00141.pdf}, author = {Walter G. Whitford} } @article {51614, title = {Supplementation effects on sheep diet and weight on semi-desert range}, journal = {Sheep Research Journal}, volume = {6}, number = {3}, year = {1990}, month = {1990}, pages = {6-13}, abstract = {

Nutritive value of range forage can be inadequate for grazing livestock when forage is mature, during periods of drought or during critical livestock physiological stages. Supplementation has been a common practice to help correct nutritional deficiencies and improve livestock performance. Better productivity associated with supplementation of various classes of range livestock is well documented. Various studies concerning range livestock response to supplementation are reviewed by Allden (1981) and Holechek et al. (1989). Mechanisms by which supplementation improves livestock performance have been reviewed by Horn and McCollum (1987) and Petersen (1987). Diet selectivity can affect livestock nutritional status (Heady 1964). Holechek et al. (1989) reviewed various studies showing livestock vary their preference as the season progresses. Research evaluating the effects of protein supplementation on sheep diet, seasonal botanical composition and quality is unavailable for New Mexico rangelands.

}, url = {/files/bibliography/355.pdf}, author = {Hamadeh, S.K. and Clarence V. Hulet and R. R. Rouda and Jerry L. Holechek} } @article {51620, title = {Substitution of DL-methionine for soybean meal as a winter supplement for gestating cows grazing native range}, journal = {Journal of Animal Science}, volume = {68}, year = {1990}, month = {1990}, pages = {4361-4375}, abstract = {

A winter grazing study was conducted to determine whether DL-methionine could replace soybean meal as a N supplement for gestating beef cows. During two winters (Trial 1, n = 51; Trial 2, n = 60), crossbred beef cows grazed native foothill range. Three treatment groups were supplemented with either none (CON), DL-methionine (7.5 g Trial 1 and 9 g Trial 2) in .5 kg beet pulp carrier (BPM) or .4 kg soybean meal (SBM). Cows were supplemented individually every other day. Small differences were noted in cow BW, condition score and blood metabolites. Unsupplemented cows lost the greatest amount of BW (P less than .01) in both trials and lost more (P less than .05) condition during Trial 1 than cows fed BPM or SBM supplements. Blood samples were obtained on two consecutive days during each trial (45 d and 25 d prepartum) and analyzed for blood urea N, total bilirubin, creatinine, albumin, total protein and cholesterol. A treatment x day preparatum interaction (P less than .05) was noted for blood urea. Blood urea nitrogen declined as gestation length increased for CON and SBM cows, but blood urea of BPM-supplemented cows remained low and unchanged. In situ forage digestion was measured in 12 ruminally cannulated cows (four/treatment). In both trials, in situ rate of NDF disappearance was greater (P less than .05) for SBM than for BPM. In Trial 2, a treatment x sampling hour interaction was detected for purine concentration of whole ruminal contents; SBM maintained greater purine concentrations throughout the 48-h supplementation cycle than BPM did. Principal component analysis suggested that ruminal ammonia limited the microbial growth response to DL-methionine. Therefore, alternate-day supplementation of DL-methionine plus beet pulp did not effectively substitute for soybean meal in these trials.

}, url = {/files/bibliography/704.pdf}, author = {Lodman, D.W. and M.K. Petersen and Clark, C.K. and Wiley, J.S. and Kris Havstad} } @article {51622, title = {Spatial variability of CaCO3 solubility in a Chihuahuan Desert soil}, journal = {Arid Soil Research and Rehabilitation}, volume = {4}, year = {1990}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1990}, pages = {181-191}, abstract = {

Spatial variability in CaCO3 solubility is an important factor in parameterizing simulation models and designing experiments. The objective of this study was to quantify the spatial variability, both horizontal and vertical, in CaCO3 solubility in a Chihuahuan Desert soil. CaCO3 solubilities were estimated in 1:5 soil:water suspensions. Soil horizon extracts were generally supersaturated with respect to calcite. The mean (+- 1 SE) pIAP(CaCO3) for the A, Bk1, and Bk2 horizons were 8.03 (0.055), 8.19 (0.019), and 8.26 (0.15), respectively. The differences in pIAP between the A and B horizons (vertical variability) were statistically significant; these differences could be due to organic matter inhibition of calcite precipitation. Supersaturation with respect to calcite and vertical variability in CaCO3 solubility needs to be explicitly considered in simulation models. The standard errors in pIAP (horizontal variability) were greatest for the A horizons and decreased with increasing soil depth. Given the inherent variability in CaCO3 solubility, a large sample size is necessary to detect small differences in CaCO3 solubility for this Chihuahuan Desert soil.

}, keywords = {article, articles, calcium carbonate, solubility, calcium carbonate, spatial variability, caliche, also SEE , journal, journals, simulation modelling, SEE , soil chemistry, soil, also SEE }, doi = {10.1080/15324989009381247}, url = {files/bibliography/JRN00131.pdf}, author = {G. M. Marion and W. H. Schlesinger and P. J. Fonteyn} } @article {51629, title = {Soil-Landscape Relationships in Alluvium Sediments in Southern New Mexico}, year = {1990}, note = {//NMSU//LTER I//}, month = {1990}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, abstract = {One of the LTER sites is in southern New Mexico on the Jornada Experimental Range. This paper describes the soil survey that was done for the study area. A soil survey was begun in the summer of 1983 to provide information for the assessment of the correlation between soil variation and the numerous biotic or soil moisture parameters along the transect. The survey objective was to prepare soil information that could be used to assess research in progress in the study area.}, keywords = {book, books, chapter, chapters, geomorphology, report, reports, soil survey, soil, alluvium sediments, soil-landscape relationships, transect, soil profile}, isbn = {Bulletin 746}, author = {M. H. Nash and LeRoy A. Daugherty} } @article {51628, title = {Statistical comparison of soil map-unit boundaries}, journal = {Soil Science Society of America Journal}, volume = {54}, number = {6}, year = {1990}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1990}, pages = {1677-1681}, abstract = {

Locating the exact boundaries of soil map units is one of the primary objectives for soil surveyors. Statistical methods were used to assure the most accurate location. Soil spatial variability, autocorrelation function, and soil boundary locations were examined along a 2700-m transect in southern New Mexico. Eighty-nine observation points were equally spaced along the transect. Selected physical and chemical characteristics through the transect were determined. A mulitvariate method of principal-component analysis was used to produce one set of data. These data were first inspected for stationary manner, i.e., that the mean and variance of each property remain fairly constant for each data set. Log-normal transformation was used to detrend the data. The stationary manner of autocorrelations was tested with semivariograms. The range of dependence obtained from the autocorrelations and semivariograms was used in a squared-Euclidean-distance procedure to locate the soil boundaries. These boundaries were compared with those obtained by conventional soil-survey methods. Some of the calculated boundaries agreed with those obtained by conventional soil survey. The latter method is more economical and more productive than the statistical method.

}, keywords = {article, articles, geomorphology, journal, journals, soil, map-unit boundaries, soil,spatial variability, transect, soil}, doi = {10.2136/sssaj1990.03615995005400060029x}, url = {files/bibliography/JRN00132.pdf}, author = {M. H. Nash and LeRoy A. Daugherty} } @article {JRN55155, title = {Soil Microarthropod Fauna of Four Habitats of the Rio Puerco Watershed, New Mexico}, journal = {The Southwestern Naturalist }, volume = {35}, year = {1990}, month = {September 1990}, pages = {279-284}, abstract = {

A shrubland, a woodland, and two grassland habitats were compared for populations of soil microarthropods in a semiarid watershed of New Mexico. Densities of grass rhizosphere microarthropods were generally higher, and some taxa like sminthurid collembolans were essentially limited to the grama grassland habitat. However, the rhizosphere fauna was also not quantitatively or qualitatively different from fauna of unvegetated soil or soil below the litter layer except in the grama grassland habitat. The similarity in microarthropod faunas in the soils of the four major habitats shows soil microarthropod assemblages are more a function of the organic matter content of the soil and the microclimate of the upper 10 cm than of the individual plant species.

}, keywords = {arid soils, desert soils, Fauna, Forest litter, Grassland soils, Habitats, Organic soils, soil fauna, soil organic matter, Woodland grasslands}, doi = {10.2307/3671940 }, url = {files/bibliography/JRN00024.pdf}, author = {Yosef Steinberger and Earl F. Aldon and Walter G. Whitford} } @proceedings {51647, title = {Stress and the Free-Ranging Animal, A Western Regional Research Publication}, number = {Research Report 646}, year = {1989}, month = {June 1990}, pages = {48 }, publisher = {New Mexico Agrcultural Experiment Station}, address = {Crystal Bay, NV}, abstract = {Grazed forages provide basic nutrition for most ruminant livestock and substantial wildlife populations in the United States. Grazed forages are important economically because over 35\% of the total nutritional requirements for United States beef cattle, sheep and goat populations are derived from this resource. Specific factors that effect productivity and health of domestic animals occupies the central focus of most management systems and form the basis of most current day research thrusts. These facts lend credence to the need for regional research focused on optimum and sustained production from rangelands. One method to foster regional cooperation is through regional projects such as Western Regional Project W-151 in which both state and federal research is focused on questions which not only have local but also regional importance. Regional projects normally operate within a 5-year time frame. Prior to the fifth year, the participating members make a decision on whether the project should be revised, if a new project should be submitted or if the regional research should simply be conducted under the guidelines of a continuing committee. In October 1983, the research locations participating in W-151 revised the then current project for the ensuing 5-year period (October 1, 1984 through September 30, 1989). The new regional project was given the title \"Utilization of range forage for rangeland and domestic ruminant animal production.\" Two main objectives formed the basis for this project. The first focused on activities of free-ranging livestock as they relate to livestock production efficiency and its impact on the standing crop. The second objective involved assimilating current knowledge into livestock production models for evaluating management strategies and identifying research needs.}, keywords = {free-ranging livestock, impact, management strategies, production, stress}, url = {/files/bibliography/719.pdf}, author = {D.M. Anderson and Kris Havstad and Hinds, F.C.} } @article {51654, title = {Spatial and temporal variability of higher microarthropod taxa along a transect in a northern Chihuahuan Desert watershed}, journal = {Pedobiologia}, volume = {33}, number = {2}, year = {1989}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1989}, pages = {101-111}, abstract = {

Numerous factors affect the abundance and distribution of soil microarthropods (SEASTEDT, 1984; WALLWORK et al., 1982; KAMILL et al., 1985). Few studies have separated the populations of microarthropods in litter and the mineral soil below the litter (ELKINS et al., 1982) in an attempt to examine factors affecting the species composition and numerical abundance of these organisms. Surface litter is a more exposed habitat and subject to rapid changes in water availability and thermal stresses, especially in sparsely vegetated arid environments (WHITFORD, 1986). Mineral soil is a buffered environment but provides only sparse food resources especially in arid environments........ Desert watersheds provide a number of habitats varying in soil type, vegetative cover, soil structure, soil organic matter an litter accumulations. Thus, studies of microarthropod populations on a watershed over time can provide tests of these hypotheses. Here we report the studies to test these hypotheses.

}, keywords = {acarina, article, articles, collembola, journal, journals, microarthropod,distribution, psocoptera, soil,microarthropod, transect,microarthropod taxa}, doi = {10.1016/S1002-0160(15)60056-X}, url = {files/bibliography/89-Pedio-Whitford.pdf}, author = {J. G. Cepeda-Pizarro and Walter G. Whitford} } @article {51655, title = {Species abundance distribution patterns of microarthropods in surface decomposing leaf-litter and mineral soil on a desert watershed}, journal = {Pedobiologia}, volume = {33}, year = {1989}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1989}, pages = {254-268}, abstract = {

Mass losses from litter bags of surface creosote bush litter placed along a Chihuahuan Desert watershed were measured to answer the following questions: (1) Do edaphic factors affect organic matter losses? (2) Are there differences in mass losses between the litter of the site-dominant plant species and creosote bush leaf litter? We hypothesized that (1) mass losses of all litter types would be higher at the base of the watershed and lower on the upper portions of the watershed and (2) mass losses of the litter of the site-dominant plants would be higher than those of creosote bush leaf litter in the same site. Mass losses from creosote bush leaf litter did not follow the moisture-organic matter gradient present in the watershed. Mass losses were higher at mid-slope run-on areas than in upper-slope erosional sites and the dry lake basin. Mass losses were highest where subterranean termite activity was the highest. There were differences between losses from the litter of the site-dominant and creosote bush leaf litter in some instances, but these differences were not attributable to differences in lignin content nor C:N ratio. Mass losses of litter of site-dominant species were not always higher than that of creosote bush leaf litter in the same site. Mass losses were best described by the double exponential model.

}, keywords = {article, articles, decomposition,microarthropod, journal, journals, litter,microarthropod, microarthropod,distribution, soil,microarthropod}, doi = {10.2307/2426560 }, url = {files/bibliography/JRN00107.pdf}, author = {J. G. Cepeda-Pizarro and Walter G. Whitford} } @mastersthesis {51682, title = {Spatial behavior and diet selection of cattle and bonded and non-bonded small ruminants grazing arid rangeland}, year = {1989}, note = {//NMSU//NONE//}, month = {1989}, pages = {112}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {This study investigated cattle, sheep and goat behavior, distribution, fecal botanical composition and liveweight change under multispecies grazing using bonded and non-bonded (control) livestock groups during the summer growing season. The study area was located on the Jornada Experimental Range, 37 km north of Las Cruces in southern New Mexico. Vegetation of the experimental paddock is classified as semidesert grassland. Precipitation during the study was 14\% above the long-term average of 18.7 cm. Control and bonded animals were maintained as separate groups and rotated between two paddocks. Scan sampling of each animal{\textquoteright}s location and behavior was conducted at consecutive hourly intervals between sunrise and sunset. Fecal samples were collected following each 7 d period of grazing paddock 10B. Composition of standing crop was evaluated immediately after each treatment group was removed from the paddock. Sheep and goats were weighed immediately upon entering and leaving paddock, cattle were not weighed.}, keywords = {behavior,cattle, behavior,goat, behavior,sheep, cattle,diet, dissertation, dissertations, flerd,grazing behavior, goat,diet, grazing behavior, cattle, grazing behavior,flerd, grazing behavior,goat, grazing behavior,sheep, grazing management, ruminant, also SEE , ruminant,behavior, ruminant,diet, sheep,diet, theses, thesis}, author = {V.B. Nakamatsu} } @book {51684, title = {Stable isotope ratios and the dynamics of caliche in desert soils}, series = {Stable Isotopes in Ecological Research}, number = {Volume 68}, year = {1989}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//ProCite field[6]: InProCite field[32]: Ecological Studies}, month = {1989}, pages = {309-317}, publisher = {Springer-Verlag}, organization = {Springer-Verlag}, address = {New York}, abstract = {

In the present paper, we review studies of stable isotopes in soil carbonates and offer some preliminary data from our current studies of how biotic processes may affect the formation of caliche and its stable isotope content. Studies of the isotopic ratios in soil carbonates suggest that biota play a major role in the soil-forming processes of desert ecosystems. The isotopic composition of caliche forming in current conditions appears to be related to brad climatic patterns and to local conditions of vegetation. Many previous compilations of such data are uninterpretable because samples were collected from sites dominated by calcareous parent materials and from soil horizons that developed under unknown paleoclimatic conditions. Gardner (1984) reported that Pleistocene age caliches contain lower values for 18O than Holocene samples (cf. Cerling et al. 1077; Table 18.1). Such changes may suggest that the deposition occurred in a cooler climate, but changes in the evaporative removal of soil moisture may also be involved. Careful studies of the seasonal change in the 13C and 18O values of soil CO2 and soil H2O would help determine the mechanisms controlling the deposition of carbonate in desert soils.

}, keywords = {biogeochemistry, calcium carbonate, biogeochemistry, stable isotope ratios, book, books, calcium carbonate, SEE , caliche, caliche, stable isotope ratios, chapter, chapters, report, reports, soil CO2, stable isotope}, url = {files/bibliography/JRN00108.pdf}, author = {W. H. Schlesinger and G. M. Marion and P. J. Fonteyn}, editor = {P. Rundel and J. R. Ehleringer and K. A. Nagy} } @article {51694, title = {A study of rainfall simulators, runoff and erosion process, and nutrient yields on selected sites in Arizona and New Mexico}, year = {1989}, note = {//OTHER//NONE//}, month = {1989}, institution = {New Mexico Water Resources Research Institute}, address = {Las Cruces, New Mexico}, abstract = {This technical report contains the results of a study on the utility of using rainfall simulation in southwestern watersheds. Two different simulators were compared on three sites. Analysis of the data indicates that the simulators provide similar results for infiltration characteristics, and that sediments yields were about 4.0 times higher for the small simulator. Numerous water chemistry samples were analyzed to determine potential nutrient loadings from forest and range lands to water bodies in New Mexico.}, keywords = {book, books, chapter, chapters, hydrology, model, hydrology, processes, hydrology,infiltration, hydrology,nutrients, hydrology,runoff plot, hydrology,sediment yield, model,hydrology, nutrients,hydrology, rainfall simulation, report, reports, soil erosion}, isbn = {WRRI Report No. 241}, author = {Timothy J. Ward and Bolin, Susan B.} } @article {51701, title = {Soil physical properties at the Las Cruces trench site}, year = {1989}, note = {//NMSU//LTER I//}, month = {1989}, institution = {University of Arizona}, address = {Tucson, Arizona}, abstract = {In a previous report, Wierenga et al. (1988) presented results of the first trench experiment. The purpose of the present report is to bring together in one report all data collected during the course of the experiment on the morphology of the soil at the site, and on the physical properties of the soil. In addition, a short description of the experimental sites is presented. No analysis of the data is included with this report.}, keywords = {book, books, chapter, chapters, geochemistry, geomorphology, report, reports, soil, NRC trench, soil, physical properties, trench study}, isbn = {Soil and Water Science Report No. 89-002}, author = {Peter J. Wierenga and D. B. Hudson and Vinson, Joe and M. H. Nash and Toorman, Alex} } @article {51703, title = {Seasonal stocking of tobosa managed under continuous and rotation grazing}, journal = {Journal of Range Management}, volume = {41}, number = {1}, year = {1988}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {January 1988}, pages = {78-83}, abstract = {

Tobosa (Hilaria mutica [Bucks.] Benth.) was seasonally grazed with cattle under high-density (2.1 to 5.1 animal unit/hectare [AU/ ha]) rotation and low-density (0.33 and 0.39 AU/ha), continuous stocking in 1980 and 1981, respectively. Tobosa leaf and culm color were used to evaluate forage quality. At the end of the 1980-81 growing seasons, crude protein was highest in green tobosa (8.4\%) and lowest in gray tobosa from the previous seasons (4.7\%). Grazing strategies did not influence the proportion of green tobosa within the standing crop; however, flexible rotation produced a more uniform use of green tobosa within the tell when compared to grazing with fixed intervals between rotations. Grazing patterns result from improper utilization of green tobosa which in future years will senesce into gray colored tobosa that composed 46-91\% of the standing crop. In this study, flexible rotation of cattle among paddocks, based on a 30-35\% reduction of tobosa standing crop height, reduced gray tobosa within the standing crop more than did continuous stocking. Total heifer siveweight gain per ha in 1980 and 1981, respectively, was 43 and 24\% less under continuous stocking compared to rotation grazing management.

}, keywords = {heifer average daily gain, seasonal grazing strategies, standing crop quality, tobosa utilization}, doi = {10.2307/3898796 }, url = {/files/bibliography/323.pdf}, author = {D.M. Anderson} } @proceedings {51707, title = {A simulation model using environmental cues to predict phenomenologies of winter and summer annuals in the northern Chihuahuan Desert}, year = {1988}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//ProCite field[6]: In}, month = {1988}, pages = {235-260}, abstract = {The goal of this study was to quantify the controls of environmental cues on the phenological patterns of northern Chihuahuan Desert annuals. Our specific objectives were to: 1) identify primary environmental cues which result in the germination of summer and winter annuals, 2) quantify the required periods of adequate temperature and soil moisture following germination which insure successful seed set, and 3) incorporate these data into a phenology model (PHENANN) in order to examine life history patterns of Chihuahuan Desert annuals in response to long-term climate records. This work is an extension of Freas and Kemp (1983) and Kemp (1983). Data from Kemp (1983) were used to develop the model which was validated using an independent data set from the Long Term Ecological Research (LTER) Jornada site. Results of the validation indicate that annual plant phenologies in this region can be reasonably predicted based on cues of rainfall, soil moisture, and temperature. In a long-term simulation based on climatic records from 1892 - 1981, summer annuals germinated 8 out of 10 years and succesfully completed their life cycles 91\% of the time; winter annuals germinated 6 out of 10 years and successfully completed their life cycles about 71\% of the time. Limitations of the model are discussed.}, keywords = {abstract, abstracts, annual plant,germination, annual plant,phenology, conference, conference proceedings, conferences, germination,annual plant, model,annual plant phenology, phenology,annual plant, proceeding, proceedings}, author = {Dominique Bachelet and Steven M. Wondzell and J. F. Reynolds}, editor = {Marani, A. (ed.)} } @article {51709, title = {Sex in Ephedra trifurca (Ephredraceae) with relation to Chihuahuan Desert habitats}, journal = {The American Midland Naturalist}, volume = {119}, number = {1}, year = {1988}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1988}, pages = {137-142}, abstract = {Spatial patterns of Ephedra trifurca populations were examined in seven vegetative zones along an elevational gradient in the Chihuahuan Desert near Las Cruces, New Mexico. Ephedra density and mean biomass differed significantly among zones, with variations that were not a consistent function of soil moisture. Higher proportions of female plants did not occur in areas of higher soil moisture availability, as has been previously reported for another Ephedra species in desert habitats.}, keywords = {article, articles, Ephedra, sex ratios, Ephedra, spatial patterns, Ephedra,vegetative patterns, journal, journals, shrub, Ephedra, transect, Ephedra, transect, population dynamics}, author = {Brunt, James W. and Marsha R. Conley and Gary L. Cunningham} } @article {51712, title = {Seasonal food habits of blacktailed jackrabbits (Lepus californicus) in southern New Mexico}, journal = {The Southwestern Naturalist}, volume = {33}, number = {3}, year = {1988}, note = {//NMSU//NONE//}, month = {1988}, pages = {367-370}, abstract = {Diet of the blacktailed jackrabbit (Lepus californicus) varies seasonally in response to forage maturity and availability (Vorhies and Taylor, 1933). Grasses and forbs tend to dominate the diet in early spring and summer (Flinders and Hansen, 1972). Shrubs become more important in late fall and winter (Hansen and Flinders, 1969)....In spite of the large number of studies on diets of jackrabbit, only those of Dabo et al (1982) and Griffing and Davis (1976) were conducted in southern New Mexico, and they studied diets only for the summer months. The major objective of this study was to examine seasonal patterns of dietary composition of diets of blacktailed jackrabbits.}, keywords = {article, articles, food habits,Lepus, journal, journals, lagomorph,food habits, Lepus, food habits}, author = {Fatehi, Mohammad and Pieper, Rex D. and Reldon F. Beck} } @booklet {51716, title = {Supplement to the Desert Project Guidebook 1988}, year = {1988}, note = { //LOCAL//NONE//}, month = {1988}, publisher = {New Mexico Bureau of Mines and Mineral Resources}, address = {Socorro, New Mexico}, abstract = {

The 3 1/2-day study tour presented in the Desert Project Guidebook gives information for 22 of the Desert Project study sites, which are designated Study Areas in the Guidebook. Supplements, to be prepared as needed and to be used with the Guidebook, were envisioned as a way of presenting additional information. This supplement, the first, is being prepared partly for a 2-day field trip for the International Working Meeting on Soil Micromorphology in San Antonio, Texas, and partly to serve the needs of future field study sessions. This is a rough first draft, and a number of sections have yet to be added. Several new Study Areas have been added in this draft, and additional ones are planned for the published supplement. Objectives of the Study Areas are to illustrate soil-geomorphic relationships, to present features significant to soil genesis and classification, to show how and why these features change from one soil to another, and, where possible, to show on the landscape where such changes are likely to take place.

}, keywords = {book, books, chapter, chapters, Desert Project, geomorphology, report, reports, soil, classification, soil, geomorphic relationships, soil, landscape}, author = {L. H. Gile and J. Hawley and R. Grossman and Curtis H. Monger} } @proceedings {51719, title = {Season and supplementation effects on ovarian activity in fine-wool ewes grazing native range or in confinement}, volume = {39}, year = {1988}, month = {1988}, pages = {86-89}, abstract = {

Effects of season and supplementation on incidence and rate of ovulation in multiparous, non-lactating ewes were investigated under range and dry-lot conditions over a 1-year period. In the range trial, 45 ewes received one of three nutritional treatments, range forage alone (R) and range forage supplemented with either 0.33 kg{\textbullet}head-1 {\textbullet} d-1 pinto beans (RB) or 0.45 kg{\textbullet}head -1 {\textbullet}d-1 \ alfalfa pellets (RP). Another 45 ewes were maintained in dry lots and fed 1.33 kg{\textbullet}head-1 \ {\textbullet}d-1 \ prairie hay (H) and either pinto beans (HB) or alfalfa pellets (HP) at the same rates used in the range trial. Ovarian structures were observed by laparoscopy at monthly intervals, except during breeding season (September-January). Supplemented ewes in both trials were heavier (P\<.05) than R and H ewes during most of the study. In the range trial, incidence of ovulation and ovulation rate tended to be higher in RB ewes in April (P = .21) and June (P = .33 and P = .24 respectively) compared to R and RP ewes. In the dry-lot trial, ovulation rate tended to be higher in HB ewes (P = .21) in February and in HP and HB ewes (P = .13) in March compared with H ewes. Except for those trends, seasonality of ovulation was ,not influenced by supplementation (P\>.40). Incidence of ovulation approached zero in \ dry-lot ewes in April, May, June and July. In contrast 43\%, 27\%, 35\% and 21\% of range ewes were ovulating during those same months.

}, url = {/files/bibliography/332.pdf}, author = {Hamadeh, S.K. and Clarence V. Hulet and Ross, T.T.} } @mastersthesis {51721, title = {A survey of twenty-four grazed and non-grazed areas in southern New Mexico}, year = {1988}, note = {//NMSU//NONE//}, month = {1988}, pages = {96}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {In southern New Mexico, a regional shift in vegetation is occurring, toward shrub desert (principle species Prosopis glandulosa, Larrea tridentata, Flouensia cernua and Gutierrezia sarothrae) and away from semidesert grassland (Bouteloua eriopoda, and other grasses). Many investigators feel livestock overgrazing in the early 1900{\textquoteright}s, coupled with recurrent drought, was chiefly responsible. Recent grazing pressure has been light or moderate, however. Accordingly the role of livestock in the desertification process in southern New Mexico was assessed, to determine if recent livestock grazing influenced plant community attributes. Species frequency, lifeform category frequency, and average number of species per square meter (diversity) were examined at 24 exclosure sites in three plant communities (mixed grasslands, mixed brush and lowland communities). Exclosures examined ranged from 5 to 74 years in age. Results indicated few species exhibited any form of trend for higher or lower frequencies under grazing, versus under protection within exlcosures. Mixed grasslands exclosure sites had slightly higher species diversity under grazing. Mixed brush sites had slightly lower diversity under grazing. It therefore appears contemporary livestock grazing pressures are not directly causing further change from semidesert grassland to shrub desert. The survey also indicated protection from grazing here in souther New Mexico did not result in the development of a different flora within exclosures as compared to grazed areas, even within decades-old exclosures. Even so, the author suggests alteration of grassland structure and the vegetational mosaic has occurred. Interactions between livestock, native small herbivores and favorable weather patterns will further shrub stand establishment and spread. Ultimately the semidesert grassland will disappear unless appropriate measures are undertaken soon.}, keywords = {cattle grazing, exclosures, cattle grazing, vegetation change, dissertation, dissertations, theses, thesis, vegetation change, cattle grazing}, author = {Herman, Hilary J.} } @article {51736, title = {Spatial variability of termite gallery production in Chihuahuan Desert plant communities}, journal = {Sociobiology}, volume = {14}, year = {1988}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1988}, pages = {281-289}, abstract = {We compared the production of termite [Gnathamitermes tubiformans (Buckley)] gallery carton along 2 transects passing through several plant communities in the northern Chihuahuan Desert of New Mexico. There was significantly more gallery carton produced on a mixed basin slope than on the creosotebush scrub zone or on grassland zones. Gallery carton had a rapid turnover rate. When termites were present, production ranged from 1000-5650 kg/ha/yr accounting for nitrogen inputs of 145-830 g/ha/yr. Our data suggest that subterranean termites are not a nitrogen sink as has been suggested in the literature, and that the inputs and outputs of nitrogen in the termite population are about equal.}, keywords = {article, articles, gallery carton, also SEE , gallery carton, nitrogen, gallery carton, turnover, Gnathamitermes, journal, journals, termite, gallery carton, termite, spatial variability, transect, termites}, author = {William P. MacKay and Walter G. Whitford} } @article {51755, title = {Strategies for Classification and Management of Native Vegetation for Food Production in Arid Zones}, year = {1987}, note = {//NMSU//LTER II//}, month = {1987}, pages = {257}, institution = {USDA Forest Service}, type = {pp}, address = {Ft. Collins, Colorado}, abstract = {

Aldon Earl F., Gonzales Vicente, Carlos E., Moir, William H., Co-editors. 1987. Strategies for Classification and Management of Native Vegetation for Food Production in Arid Zones: symposium proceedings; 1987 October 12-16; Tucson, Arizona. Gen. Tech. Rep. RM-150. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 1987. 257p.\ 

These proceedings contain hh papers presented as part of a continuing cooperative effort in forestry and related resources between Mexico and the U. S. Sessions were held on arid land classification, sampling techniques, utilization of native plants, soil management, desertification, agrosilvicultural systems and watershed management.

Papers are in the language of the author (Spanish or English) with an abstract in the other language.

}, keywords = {book, books, chapter, chapters, report, reports, vegetation, classification, vegetation, management, vegetation,food production}, isbn = {General Technical Report RM 150}, url = {files/bibliography/JRN00061.pdf}, author = {Earl F. Aldon and Carlos E. Gonzale Vicente and Moir, William H.} } @article {51776, title = {Soil water regimes of loamy sands and sandy loams on arid rangelands of southern New Mexico}, journal = {Journal of Soil and Water Conservation}, volume = {42}, year = {1987}, month = {1987}, pages = {442-447}, abstract = {

The matric potential of soil water is presented for five loamy sand and six sandy loam sites on arid rangelands. Gypsum-impregnated resistance blocks were placed at five soil depths to 91 cm. 1f caliche was encountered before the 91-cm depth, blocks were placed to that level. The average annual precipitation during the approximate 20-year study period was 237 mm, slightly above the long-term mean. At the 10-cm depth, the probability of soil matric potential >= - 1.5 MPa during December-April was 69\% at the 11 sites; 83\% of the probability was >= -0.1 MPa. During July-September, the probability of soil matric potential at the 10-cm depth was 53\%; 73\% was \> -0.1 MPa. Factors affecting soil matric potential were precipitation amount, surface soil characteristics, topography, subsurface conditions, and season of the year.

}, url = {/files/bibliography/317.pdf}, author = {C.H. Herbel and Gibbens, Robert P.} } @article {51791, title = {A simulation model of soil nematode population dynamics: effects of moisture and temperature}, journal = {Pedobiologia}, volume = {30}, year = {1987}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1987}, pages = {361-372}, abstract = {

We are currently constructing a simulation of primary productivity, decomposition and nitrogen cycling in a Chihuahuan desert ecosystem (Moorhead et al. 1987). This ecosystem simulation model will be used to address hypotheses concerning mechanisms of interactions and feedbacks which exist between the various organisms involved in carbon and nitrogen flow in deserts. The soil organism community is an important component of this model because of its recognized role in regulating numerous processes, e.g., nitrogen mineralization (Swift et al. 1979, Anderson et al. 1985). In this paper, we present a descriptive submodel of the population dynamics of a general bacterivorous nematode as influenced by soil temperature and moisture. Recent investigations suggest that nematodes may play an important role in regulating decomposition processes and nutrient cycling by grazing on microflora and microfauna (Yeates 1979, Ingham et al. 1985).

}, keywords = {article, articles, ecosystem, journal, journals, model, model,population dynamics, model,simulation, nematode,moisture and temperature, nematode,population dynamics, population dynamics,nematode, soil fauna}, url = {files/bibliography/JRN00049.pdf}, author = {Daryl L. Moorhead and D. W. Freckman and J. F. Reynolds and Walter G. Whitford} } @article {51792, title = {Soil seed banks associated with individual broom snakeweed plants}, journal = {Journal of Range Management}, volume = {40}, number = {5}, year = {1987}, note = {//NMSU//NONE//}, month = {1987}, pages = {441-443}, abstract = {The influence of individual broom snakeweed (Gutierrezia sarothrae [Push] Britt. \& Rushby) plants on the distribution of buried viable seed and the distribution of plants in the field was studied in a desert grassland in southern New Mexico. Surface soil samples collected at 3 distances from a central broom snakeweed plant were watered in pots in a greenhouse and numbers of each specie emerging were counted. Densities of each species were also determined in the field. Some species (Sporobolus flexuosus [Thrub.] Rybd., S. contractus Hitche., Descurainia pinnata [Walt.] Britton, and Dithyre wislizenii Engelm.) emerged in greatest numbers from soil collected in the zones closest and at the greatest distances from the broom snakeweed. Emergence of other species declined in relation to distance from the central snakeweed plant. In the field, grasses generally increased in relation to distance from the central broom snakeweed plant while the pattern for forbs was not consistent.}, keywords = {article, articles, Gutierrezia, effects on forbs and grasses, Gutierrezia,seed bank associations, Gutierrezia,vegetational zonation, journal, journals, seed bank,Gutierrezia association, soil, Gutierrezia, soil, seed banks, vegetational zonation,Gutierrezia}, author = {Abdelgader Osman and Pieper, Rex D. and K. C. McDaniel} } @article {51794, title = {Soil moisture content and plant transpiration in the Chihuahuan Desert of New Mexico}, journal = {Journal of Arid Environments}, volume = {12}, year = {1987}, note = {//NMSU//LTER I//}, month = {1987}, pages = {119-126}, abstract = {

Thermocouple hygrometers were used to monitor soil water potential in control and harvested (bare) plots in the Chihuahuan Desert of New Mexico (U.S.A.) from June 1983 and June 1984. Soil water potentials were converted to water contents using the moisture tension release characteristics for each soil horizon. Comparisons of seasonal fluctuations in soil water storage on these plots suggest that 72\% of incident precipitation is removed by plant transpiration in this ecosystem. Plant uptake of water from the lower soil profile is an important factor affecting the rate and depth of CaCO3 deposition in desert soils.

}, keywords = {article, articles, caliche deposition, journal, journals, plant transpiration, caliche deposition, soil moisture content, soil water, content, soil water, potential}, doi = {10.1016/S0140-1963(18)31182-0}, url = {files/bibliography/JRN00060.pdf}, author = {W. H. Schlesinger and P. J. Fonteyn and G. M. Marion} } @conference {51799, title = {Selection to increase farm income}, booktitle = {Journal of Animal Science, 79th Annual Meeting, American Society for Animal Science}, volume = {65(Suppl 1)}, year = {1987}, month = {1987}, pages = {No. 25-200}, author = {Terrill, C E. and Ercanbrack, S.K. and Clarence V. Hulet and A. D. Knight and Stoddard, B.J.} } @article {51821, title = {Short-term storage of cotton pollen}, journal = {Plant Cell Reports}, volume = {5}, year = {1986}, month = {1986}, pages = {332-333}, abstract = {

Several methods of storing cotton pollen (Gossypium hirsutum L.) were evaluated. A successful pollen storage method that maintains fertility would enhance the crossing of breeding materials. Storing pollen at ultra-low temperatures in liquid nitrogen or at 5{\textdegree}C was not successful. No storage method maintained pollen fertility for more than 72 h. Cotton pollen did maintain adequate fertility up to 24 h at 10 and 15{\textdegree}C, at both low and high humidity when the pollen was stored in the detached flowers. Minimally acceptable pollen fertility was maintained in flowers stored at 15{\textdegree}C at 100\% R.H. for 72 h. Use of these methods will allow for better utilization of parental plants when both parents do not flower on the same days.

}, doi = { 10.1007/BF00268594}, url = {/files/bibliography/711.pdf}, author = {Garay, B.R. and J.R. Barrow} } @article {51822, title = {Some Impacts of 2, 4, 5-T on a mesquite duneland ecosystem in southern New Mexico: A synthesis}, journal = {Journal of Range Management}, volume = {39}, number = {4}, year = {1986}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {July 1, 1986}, pages = {320-326}, abstract = {

Two aerial applications of 2,4,5-T [(2,4,5-trichlorophenoxy) acetic acid] were applied to 3,634 ha of mesquite (Prosopis glandulosa Torr. var. glandulosa) dunelands in southern New Mexico. Herbicide residuals; herbaceous plant production; soil microorganisms; insect, small mammal, and bird populations; cattle weights; travel; time budgets; and diets were studied on the treated area and an adjacent, untreated area. Stem kill of mesquite ranged from 17 to 66\%. Herbicide residuals in soils and plant tissue on the treated area dissipated within a single season. Herbaceous plant production was measured for 5 years on a small area sprayed in 3 consecutive years and on untreated rangeland. Production was greater on the sprayed than on the unsprayed area for the first 3 years and was about the same on both areas for the next 2 years. Microbial populations were not numerically different between treatments but dehydrogenase activity and C02 evolution were greater in dunal than interdunal soils. Numbers of tenebrionid beetles (Coleoptera: Tenebrionidae) did not differ between treatments. More mesquite leaf tiers (Tetralopha euphemella) were found on the sprayed area than on the untreated area. Population statistics for small mammals were similar on both treatments. More bird species were found on untreated than on sprayed areas. Cattle weights, travel, and time budgets did not differ between treatments and there were only minor differences between treatments in cattle diet quality. The sprayed area supported over twice as many A UM{\textquoteright}s of grazing as the untreated area in the first 3 post treatment years. In the second post-treatment year, cattle liveweight produced was 2.9 and 1.5 kg/ha on the sprayed and untreated areas, respectively. Overall, the 2,4,5-T treatment caused relatively minor perturbations in measured ecosystem components.

}, url = {/files/bibliography/291.pdf}, author = {Gibbens, Robert P. and C.H. Herbel and Morton, H.L. and W. C. Lindemann and J. Ryder-White and D. Richman and E.W. Huddleston and W.H. Conley and C.A. Davis and J.A. Reitzel and D.M. Anderson and A. Guiao} } @article {51827, title = {Soil sorting by forty-five years of wind erosion on a southern New Mexico range}, journal = {Soil Science Society of America Journal}, volume = {59}, year = {1986}, month = {1986}, pages = {391-394}, abstract = {

This paper presents the fractional composition of soil lost from wind erosion for a 45-yr period on mesquite sand dune rangeland in south central New Mexico. In addition, an equation was developed for defining the soil loss by particle size. Three arbitrarily chosen groups (deposition, noneroded, and eroded) were used to categorize the sampling locations. Net soil loss was in excess of 4.6 cm/ha. Maximum deposition was 78.6 cm and maximum erosion was in excess of 61.9 cm. The sand fraction was divided into three particle size classes. There was a significantly greater amount of the 0.5- to 0.05-mm sand fraction in the deposition site than in either the eroded or non-eroded sites. No net loss of sand from the experimental site was measured. The silt fraction was significantly greater in the noneroded and eroded sites than in the deposition site, indicating removal of the silt fraction by wind erosion. Wind erosion occurring on the site is resulting in a more sandy textured soil.

}, keywords = {arid rangelands, sandy soils, soil erosion, soil movement, wind}, url = {/files/bibliography/292.pdf}, author = {J.T. Hennessy and Kies, B. and Gibbens, Robert P. and J.M. Tromble} } @inbook {51829, title = {Seeding shrubs in the field}, booktitle = {Forage and Fuel Production from Salt-Affected Wasteland}, year = {1986}, month = {1986}, pages = {377-385}, publisher = {Elsevier Science Publisher}, organization = {Elsevier Science Publisher}, address = {Amsterdam, The Netherlands}, abstract = {

Production from degraded rangeland may be increased by sowing with shrubs. Before reseeding an area it should be established that a change in plant cover is desirable and that the terrain is suitable for seeding. Rainfall or water supply should be adequate to ensure survival of seeded species. It may be desirable to sow mixtures of species. Care should be taken in the preparation of the seed bed and in optimizing seeding rate, spacing and depth. Factors which may be important in ameliorating harsh environmental conditions include the use of mulches, water ponding and soil compaction.

}, keywords = {mulches, seeding methods, shrubs, temperature, water conservation}, url = {/files/bibliography/293.pdf}, author = {C.H. Herbel}, editor = {Barrett-Lennard, E.G. and Malcolm, C.V. and Stern, W.R. and Wilkins, S.M.} } @article {51832, title = {Seeding shrubs in the field}, year = {1986}, month = {1986}, author = {C.H. Herbel} } @article {51833, title = {Supplementing range livestock}, journal = {Rangelands}, volume = {8}, year = {1986}, month = {1986}, pages = {29-33}, abstract = {

A major operational expense confronting the range livestock industry in many parts of the United States is that for supplemental feed. Rising costs for supplemental feed coupled with declining prices for range livestock products during the last ten years have increased interest in ways to minimize supplementation costs without sacrificing livestock production.

}, url = {/files/bibliography/297.pdf}, author = {Jerry L. Holechek and C.H. Herbel} } @mastersthesis {51847, title = {Soil and vegetation factors influencing den site selection of a Chihuahuan Desert rodent assembly}, year = {1986}, note = {//NMSU//LTER I//}, month = {1986}, pages = {37}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Den site selection by thirteen species of desert rodents was studied on the Long Term Ecological Research (LTER) site in Dona Ana County, New Mexico. Vegetation and soil factors were examined to determine how they influence den site selection. Vegetation analysis revealed that vegetation factors were important to the den distributions of Perognathus falvus, Perognathus intermedius and Neotoma albigula. Soil types were found important to all species except Neotoma albigula.}, keywords = {dissertation, dissertations, rodent, den site selection, theses, thesis, transect, rodents, transect, soil factors, transect, vegetation factors}, author = {Phillips, Marcia Dawn} } @mastersthesis {51816, title = {Spatial and temporal patterns of decomposition and microarthropod assemblages in decomposing surface leaf-litter on a Chihuahuan Desert watershed}, year = {1986}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1986}, pages = {245}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {Mass loss and changes in the microarthropod assembleges were monitored in six types of decomposing surface leaf-litter confined in mesh-bags and set across a Chihuahuan Desert watershed for 17 months. High initial mass losses were observed in all litter types. Except for black grama grass litter, mass loss trends were described by the double exponential decay model............................The study supported the idea that depth and stability of the surface litter determine the size of the microarthropod community. The data did not provide clear evidence of the role played by the microarthropod fauna on surface litter breakdown.}, keywords = {decomposition, microarthropod, dissertation, dissertations, litter, microarthropods, microarthropod, assemblages, microarthropod, decomposition, microarthropod, distribution, microarthropod,temporal patterns, theses, thesis, transect, decomposition, transect, microarthropods}, author = {Cepeda Pizarro, Jorge G.} } @article {51855, title = {Seasonal nitrate reductase activity of three genotypes of Atriplex canescens in the northern Chihuahuan Desert}, journal = {Journal of Ecology}, volume = {74}, year = {1986}, month = {1986}, pages = {579-589}, abstract = {

(1) Seasonal nitrate reductase (NR) activity of the young, uppermost leaves of three genotypes (diploid, tetraploid and hexaploid) of Atriplex canescens growing in situ showed maximal activity during reproductive growth. Because rainfall coincided with reproductive growth, higher NR activity during this period may have been due to new leaf growth and increased soil-NO3) availability rather than an increased need for nitrogen due to developing seeds. The wing-like bracts of the immature fruits possessed NR and may have been a source of reduced nitrogen for seeds. (2) Seasonal leaf water content was significantly correlated with NR activity in all genotypes, and water potentials in the stem xylem were correlated with NR activity only in the tetraploid plants. (3) In a glasshouse the hexaploid plants had significantly higher NR activity and reduced-nitrogen concentrations than did either the diploid or tetraploid plants. (4) Although thermal adaptation of NR would be advantageous for plants inhabiting a desert environment where seasonal temperatures fluctuate widely, there was no evidence to suggest that acclimation of NR occurs in A. canescens growing in situ.

}, doi = {10.2307/2260275 }, url = {/files/bibliography/303.pdf}, author = {Sisson, W.B. and Throneberry, G.O.} } @article {51859, title = {Soil development under legume tree canopies}, journal = {Forest Ecology and Management}, volume = {16}, year = {1986}, note = {//OTHER//NONE//}, month = {1986}, pages = {69-79}, abstract = {Tree legumes influence soil development by altering the physical and chemical properties of the soil beneath the plant canopy. The accumulation of extractable NO3 and PO4 in soil beneath the Sonoran Desert woody legumes Prosopis glandulosa and Dalea spinosa was compared to soil from the tree interspaces. Measurements of natural 15N abundance indicate both these plants symbiotically fix N2 at the sites studied. Nutrient accumulation was related to the water regime of the site. High concentrations of symbiotically fixed N and P as NO3 and PO4 were found in the surface 60 cm of soil beneath a Prosopis stand utilizing groundwater. Relatively little NO3 or PO4 accumulated in the moist soil above the water table at 5 m. In contrast, NO3 and PO4 did not accumulate in the surface soil beneath Dalea growing in a sandy wash. Soil NO3 concentrations were lower beneath Dalea canopies than in the nonvegetated wash. The mechanisms by which tree legumes alter soil properties are reviewed. The direction and potential magnitude of soil changes in managed tree legume systems may be inferred from an understanding of the function of native plant-soil systems.}, keywords = {article, articles, Dalea,soil development, journal, journals, legume tree,soil development, nitrogen,soil, phosphorous,soil, Prosopis,soil development, soil development,legume trees, soil nutrients,nitrogen, soil nutrients,phosphorous}, author = {R. A. Virginia} } @article {51860, title = {Seasonality of some Chihuahuan Desert soil oribatid mites (Acari: Cryptostigmata)}, journal = {Journal of Zoology, London (A)}, volume = {208}, year = {1986}, note = {//NMSU//LTER I//}, month = {1986}, pages = {403-416}, abstract = {

1. Reproductive strategies of four species of oribatid mites were investigated in the Chihuahuan Desert from 1981 to 1984. 2. Breeding activity coincided with the summer rainfall period in three of the four cases: Passalozetes neomexicanus, P. californicus and Jornadia larreae. This pattern was not changed by the application of simulated rainfall at other times of the year. The strict seasonality of reproductive behavior is interpreted as an outcome of strong selection pressure to recruit only when food quality and quantity and microclimate are most favorable. 3. Joshuella striata showed a more flexible pattern which was essentially bimodal. Periods of egg production occurred in winter and also during the summer rainfall period. This pattern is consistent with the known distribution of this species in winter- and summer-rainfall deserts in south-western USA.

}, keywords = {article, articles, breeding,mites, journal, journals, mite,oribatid, mite,rainfall, mite,reproduction, rainfall simulation, microarthropods, reproduction,mites, soil mite,oribatid}, doi = {10.1111/j.1469-7998.1986.tb01903.x}, url = {files/bibliography/JRN00041.pdf}, author = {J. A. Wallwork and MacQuitty, Miranda and Solange Silva and Walter G. Whitford} } @article {51861, title = {A study of runoff and erosion processes using large and small rainfall simulators}, year = {1986}, note = {//NONE//NONE//updated 11/11/2009: Notes.}, month = {1986}, institution = {New Mexico Water Resources Research Institute}, address = {Las Cruces, New Mexico}, abstract = {Estimation of runoff and sediment yield from small, ungaged watersheds is a difficult hydrologic task. Process oriented mathematical models can be an important part in the solution of this task. Models, however, require some information which is directly related to the hydrologic processes occurring on the watershed. Rainfall simulation is an important experimental technique for gathering such information. This technical report contains the results of a pilot study on the utility of using rainfall simulation in southwestern watersheds. Two different simulators were compared on three sites in New Mexico. A small area simulator, 10 square feet, and a large area simulator, approximately 2000 square feet, were operated for a total of 60 plot experiments. The large simulator was modified and operated with variable intensity rainfall and with overland flow without rainfall for some of the experiments. Analysis of the data indicates that the simulators provide similar results for hydrologic processes, and that sediment yields averaged about 2.7 times higher for the small simulator. Addition of the variable intensity and overland flow capabilities to the large simulator have provided a means for isolating and studying those two important processes.}, keywords = {book, books, chapter, chapters, hydrology,infilitration, hydrology,model, hydrology,rainfall simulation, hydrology,runoff plot, hydrology,sediment yield, infiltration, model, runoff, model,hydrology, model,sediment yields, rainfall simulation,erosion, rainfall simulation,runoff, report, reports, simulated rainfall,SEE , soil erosion, technique, rainfall simulators}, isbn = {WRRI Report No. 215}, author = {Timothy J. Ward} } @article {51864, title = {Soil movement by desert ants}, journal = {The Southwestern Naturalist}, volume = {31}, year = {1986}, note = {//OTHER//NONE//}, month = {1986}, pages = {273-274}, abstract = {

Estimates of quantities of soil moved by the activities of ants from the soil profiel to the surface in a shinnery oak (Quercus harvardii) - mesquite (Prosopis glandulosa) area 40 km east of Carlsbad, NM. Soils were sandy loams. The average quantity of soil moved to the surface by ants during the period of surface activity (May - September) was 84.2 +/- 4 g m-2.\ 

The area is characterized by spring and summer rainfall 304 mm and a frost free period from March through October. We established twelve permanent 1 m2 plots in which we collected all the new soil of the nests of the ant colonies in these quadrats. This soil was placed in bags identified number, returned to the laboratory, dried and weighed. The quantities of soil (x \± SD) transported from deep in the soil profile to the surface workings (i.e., cleaning tunnels, new chambers, etc.) were as follows: May 8, 17.4 \± June 10, 13.5 \± 8.8 g/m-2; July 10, 2.1 \± 1.8 g/m-2; August 9, 9.8 \± 7.5 g/m-2; and, 26, 43.1 \± 19.1g/m-2.

}, keywords = {ant, soil movement, article, articles, journal, journals, soil movement, ants}, doi = {10.2307/3670582 }, url = {files/bibliography/86-SWNat-Whitford.pdf}, author = {Walter G. Whitford and Douglas Schaefer and Wendy Wisdom} } @article {51877, title = {Structure and organization of a winter community of cavity-inhabiting, web-building spiders (Pholocidae and Theridiidae) in a Chihuahuan Desert habitat}, journal = {Journal of Arid Environments}, volume = {8}, year = {1985}, note = {//NMSU//US-IBP//}, month = {1985}, pages = {57-65}, abstract = {

Populations of Chihuahuan Desert spiders that construct webs in naturally occurring cavities were followed over a 20-week-period with modified pitfall traps. Of the three species studied, Psilochorus imitatus (Pholocidae) was the most abundant, followed in order by Artema atlanta (Pholocidae) and Latroductus hesperus (Theridiidae). Canonical correlation analysis indicated a strong dependence of L. hesperus upon soil temperatures. A principal axis factor analysis explained 87 per cent of the variance in the spider-weather-habitat aspect system with five common factors. This model also gave a good fit to all monitored variables. This analysis demonstrated the importance of habitat aspect upon spider distributions, and allowed an examination of the partitioning of niche space by the three species. Experimental laboratory manipulations suggested that groups of A. atlanta can behaviorally dominate solitary L. hesperus females by restricting orb web construction, and suggested that patterns observed in the field may be shaped by interspecific competition.

}, keywords = {article, articles, journal, journals, spider, Artema, spider, cavity-inhabiting, spider, Latrodectus, spider, Psilochorus, spider, web-building, spider,community structure}, doi = {10.1016/S0140-1963(18)31337-5}, url = {files/bibliography/85-JrnlofAridEnvn-Whitford.pdf}, author = {Harold G. Fowler and Walter G. Whitford} } @article {51885, title = {Soil microarthropods from the Chihuahuan Desert of New Mexico}, journal = {Journal of Zoology, London (A)}, volume = {205}, year = {1985}, note = {//NMSU//NONE, LTER//}, month = {1985}, pages = {273-286}, abstract = {

An account is given of the soil- and litter-dwelling microarthropods collected under three species of desert shrub in southern New Mexico. Particular attention is paid to the acarine component which represents 80\% of the microarthropod fauna. Comparisons made with samples collected one hour after wetting show that only the Collembola respond rapidly to changes in the moisture content of the soil. The results of the study suggest that the depth and stability of the surface litter determine the degree to which microarthropod activity is affected by the application of water.

}, keywords = {Apache plume, Fallugia, article, articles, Celtis, Chilopsis, Desert willow, Chilopsis, Fallugia, hackberry, Celtis, journal, journals, list, microarthropods, microarthropod, litter, microarthropod, soil, plant, Celtis, plant, Chilopsis, plant, Fallugia, shrub, Celtis, soil microarthropods}, doi = {10.1111/j.1469-7998.1985.tb03534.x}, url = {files/bibliography/85-JrnlofZoolgyLondon-Whitford.pdf}, author = {B. W. Kamill and Yosef Steinberger and Walter G. Whitford} } @mastersthesis {51887, title = {Substrate utilization and guild structure in desert grasshopper assemblages}, year = {1985}, note = {//NMSU//NONE, LTER//}, month = {1985}, pages = {60}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Desert grasshopper assemblages from sites in the Great Basin and Chihuahuan deserts were assessed for guilds on the basis of substrate or microhabitat use and morphological characteristics of component species. Three techniques were used to assess grasshopper guilds: 1) cluster analysis of grasshopper species by specific substrate use, 2) assessments of species substrate class use, and 3) life form classification of grasshopper species based on morphological characteristics. There consistent guilds were evident from the results of those techniques: 1) ground-dwelling species (terriocles), 2) shrub-inhabiting species (arbushticoles), and 3) grass-inhabiting species (graminicoles). Grasshopper guild structures were similar between the Great Basin and Chihuahuan deserts even though species compositions and dominance-diversity patterns were different. Observed grasshopper guilds reflected physical structural features of the habitat such as vegetation physiognomy and edaphic properties. Explanations for observed guild structure are discussed and it is hypothesized that competition for food resources is minimal and that predation is a major selective agent structuring desert grasshopper assemblages.}, keywords = {dissertation, dissertations, grasshopper, guild structure, grasshopper, substrate utilization, theses, thesis}, author = {David C. Lightfoot} } @article {51910, title = {Successional patterns and productivity potential of the range vegetation in the warm, arid portions of the southwestern United States}, year = {1984}, month = {1984}, pages = {1333-1365}, institution = {Westview Press}, address = {Boulder, Co}, abstract = {

Arid rangelands of the Southwest are fragile, easily damaged by abusive grazing, and subject to frequent droughts. The land resources in western Texas, southern and western New Mexico, and southern Arizona have plateaus, plains, basins, and many isolated mountain ranges. The growing season precipitation occurs during the summer, and the spring period is normally very dry and occasionally windy. The plant resources include the Flourensia-Larrea shrub savanna, the Bouteloua-Hilariaprairie, the Bouteloua-Hilaria-Larrea shrub steppe, the Larrea-Flourensia association, the Bouteloua-Hilaria steppe, and the Larrea-Franseria association (Kuchler 1964). Pronghorn antelope and a number of rodents and rabbits occur throughout the area.

}, url = {/files/bibliography/260.pdf}, author = {C.H. Herbel} } @proceedings {51918, title = {Some observations on the role of behavior in sheep production and future research needs}, volume = {1}, year = {1984}, month = {1984}, pages = {407-411}, abstract = {

The influence of behavior on sheep production is not generally well understood or appreciated. There is need for behavior research to evaluate the effects of behavior in production and in experimental designs. The roles of behavior, in both intensive and range management systems, and including such factors as man-animal interactions, predation, reproduction, nutrition and transportation, are areas that deserve more research activity for optimal sheep production.

}, url = {/files/bibliography/266.pdf}, author = {Clarence V. Hulet and Bond, J.} } @proceedings {51922, title = {Seasonal nitrate reductase activity of kleingrass (Panicum coloratum L.) in the northern Chihuahuan Desert}, year = {1984}, month = {1984}, address = {Las Vegas, NV}, author = {Ray, I.M. and Sisson, W.B. and Throneberry, G.O.} } @proceedings {51925, title = {Seasonal leaf nitrate reductase activity, nitrogen and nitrate content, and water relations of Atriplex canescens (Pursh) Nutt. in the northern Chihuahuan Desert}, year = {1984}, month = {1984}, pages = {133-137}, publisher = {Intermountain Forest and Range Experiment Station, General Technical Report INT-172}, address = {Provo, UT}, abstract = {

Seasonal nitrate reductase (NR) activity of young, uppermost leaves of Atriplex canescens (Pursh)Nutt. (diploid genotype) growing in situ was maximal during reproductive growth. Because precipitation on the study site coincided with reproductive growth, higher NR activity during this periods may have been due to new leaf growth and increased soil NO3 availability rather that the nitrogen sink in developing seeds. Seasonal leaf water content (percent) was significantly ( P \< 0.10 ) correlated with NR activity. Stem xylem water potentials were not correlated with NR activity. Although thermal adaptation of NR would, in general, be advantageous for plants inhabiting a desert environment with widely fluctuation seasonal temperatures, there was no evidence to suggest that acclimation of NR occurs in A. canescens growing in situ.

}, url = {/files/bibliography/270.pdf}, author = {Sisson, W.B. and Throneberry, G.O. and Southward, G.M.}, editor = {Tiedemann, Arthur R. and McArthur, E. Durant and Stutz, Howard C. and Richard Stevens and Kendall L. Johnson} } @article {51927, title = {Spatial and temporal relationships of soil microarthropods on a desert watershed}, journal = {Pedobiologia}, volume = {26}, year = {1984}, note = {//NMSU//LTER I//}, month = {1984}, pages = {275-284}, abstract = {

...we hypothesized that microarthropod densities and numbers of taxa would be highest at the base of a closed basin watershed where organic matter and water accumulate (run-on area) and lowest at the top of the watershed (run-off area), providing the soils sampled were under the same plant species.... we hypothesized that as the soils dried following a rain event, the number of taxa and population densities of microarthropods would remain high for longer periods at the base of the watershed than at the top. The data collected in the study force us to reject our original hypotheses, i.e., that microarthropod population densities and number of taxa should be higher at the base of the watershed, exhibit a greater increase in size in response to precipitation and remain active for a longer time than on the upper slopes of the watershed. The relationships found in this study were almost the reverse of those hypothesized. Although soil organic matter and percent soil moisture were consistently higher at the base of the watershed, soil microarthropod populations were either lower than or equal to those found on the upper slopes.

}, keywords = {article, articles, journal, journals, microarthropod, spatial relationships, microarthropod, temporal relationships, soil microarthropods,also SEE }, url = {files/bibliography/84-Pedobiologia-Whitford.pdf}, author = {Yosef Steinberger and Walter G. Whitford} } @conference {51933, title = {Seasonal use of tobosa managed under continuous low-stock-density grazing (CLSDG) and rotational high stock density grazing (RHSDG)}, booktitle = {36th Annual Meeting, Society for Range Management}, year = {1983}, month = {February 14-18, }, pages = {No. 142}, address = {Albuquerque, NM}, abstract = {A 33.6- and 34.7-ha tobosa (Hilaria mutica) paddock was grazed during the summer of 1980 and 1981 for 168 and 107 days, respectively. The average stocking density (SD) with CLSDG was 0.36 A.U./ha compared to a 10-paddock, 1-herd RHSDG treatment which had an average (SD) of 3.47 A.U./ha. Stocking rates were similar in the CLSDG treatment (0.32 and 0.43 A.U./ha) and the RHSDG treatment (0.35 and 0.43 A.U./ha) during both years. Livestock management was similar during both years in the CLSDG treatment; however, the cattle were moved to sequential paddocks in the RHSDG treatment on fixed dates in 1980 while in 1981 the herd was moved based on the reduction in height of tobosa plants defoliated. Standing crop was clipped at ground level each year in both grazing treatments and in an ungrazed paddock. Animal liveweight was taken approximately every 42 and 31 days in 1980 and 1981, respectively. Total tobosa standing crop and heifer average daily gain was not significantly (P O.35) influenced by the grazing treatments. However, grazing significantly (PzO.0001) reduced the mean end-of-season tobosa standing crop approximately 58\%, regardless of grazing method, when compared to the ungrazed control (2068 + 244 kg/ha).}, keywords = {CLSDG, continuous low-stock-density grazing, RHSDG, rotational high-stock-density grazing, tobosa}, author = {D.M. Anderson} } @article {51940, title = {Some relationships between enviornmental relaibility and seed dormancy in desert annual plants}, journal = {Journal of Ecology}, volume = {71}, year = {1983}, note = {//LOCAL//NONE//}, month = {1983}, pages = {211-217}, abstract = {(1) There are two groups of annual species that grow in the northern Chihuahuan Desert of North America. Plants in one group germinate and complete their life cycle in late summer. Those in the other germinate in winter or early spring and complete their life cycle in the spring. The late summer season in characterized by abundant and reliable rain, while the winter-spring season has less abundant and less reliable rain. (2) Several theoretical models have been suggested which predict that annual plants from uncertain environments may or may not have evolved innate dormancy to offset the possibility of population extinction due to complete germination followed by complete mortality under severely unfavourable conditions. (3) We have tested these models with a comparative experiment examining the germination responses of seeds collected from an annual species which grows during the more reliable summer season and two annual species which grow during the less reliable winter-spring season. (4) The summer annual species does not have a genetically fixed innate dormancy, but the two winter annual species apparently have evolved a genetically controlled innate dormancy. (5) All three annual species exhibited environmentally-controlled seed dormancy with respect to amount of rainfall. Seeds germinated only when the equivalent of more than 10 mm of rain fell. Above 15 mm of simulated rain, germination was positively correlated with increasing amount of rain in all three species. (6) The importance of innate dormancy, water-controlled dormancy, and seed dispersal to the long-term survival of these species is discussed.}, keywords = {annual plant, germination, annual plant, rainfall, article, articles, journal, journals, Lappula, germination, Lepidium, germination, Pectis, germination, seed, germination}, author = {K.E. Freas and P. R. Kemp} } @article {51943, title = {Soil movement in mesquite dunelands and former grasslands of southern New Mexico from 1933 to 1980}, journal = {Journal of Range Management}, volume = {36}, number = {2}, year = {1983}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {March 1, 1983}, pages = {145-148}, abstract = {

Soil levels were marked on grid and transect stakes in mesquite duneland and grassland areas at 3 sites on the Jornada Experimental Range in 1933 and 1935. Soil levels on one set of transect stakes were remeasured in 1950 and 1955. Remeasurement of soil levels at both transect and grid stakes in 1980 revealed that extensive soil movement had occurred during the intervening years. On a 259-ha site containing large mesquite dunes in 1935, maximum deposition and deflation was 86.9 and 64.6 cm, respectively, in 1980. There was a net gain of 1.9 cm in soil depth over the entire area. On a 259-ha site only partially occupied by mesquite dunes in 1933, there was a net loss of 4.6 cm in soil depth and mesquite dunes had completely occupied the site by 1980. On a transect established across a mesquite duneland-grassland ecotone in 1935, there was a net loss in soil depth of 3.4 cm. Mesquite dunes had completely occupied the former grassland and dune intercept increased from 34.9 m in 1935 to 149.6 m in 1980. Gross erosion rates on wind deflated areas were equivalent to 69 tonnes ha-1 yr-1 on the area of large mesquite dunes. On the area partially occupied by mesquite in 1935 the gross erosion rate was 52 tonnes ha-1 yr-1. At the ecotone transect gross erosion rates were 45, 101, and 40 tonnes ha-1 yr-1 for 1935-50, 1950-55, and 1955-80 periods, respectively.

}, url = {/files/bibliography/232.pdf}, author = {Gibbens, Robert P. and J.M. Tromble and J.T. Hennessy and Manual Cardenas} } @inbook {51946, title = {Status and use of livestock-guarding dogs in North America}, booktitle = {Sheep and Goat Handbook}, year = {1983}, month = {1983}, pages = {423-430}, publisher = {Winrock International, Westview Press}, organization = {Winrock International, Westview Press}, address = {Boulder, CO}, abstract = {

The concept of using dogs to protect sheep and other livestock from predators is an ancient one and can be traced to many centuries B.C. in Eurasia (Bordeaux, 1974). The Spanish conquistadors brought guarding dogs with them to the western hemisphere to help protect their flocks (Lyman, 1844). Darwin (1839) noted that guarding dogs were commonly seen with large flocks of sheep in South America. Despite this long history, with the exception of the Navajo Indians who have used dogs with their sheep and goats since the early 1700{\textquoteright}s (Black, 1981), the use of dogs to protect livestock in the United States is relatively new.

}, url = {/files/bibliography/233.pdf}, author = {Green, J.S. and Woodruff, R.A. and Clarence V. Hulet}, editor = {Baker, F.H.} } @article {51965, title = {Soil respiration in a Chihuahuan Desert rangeland}, journal = {Soil Biology and Biochemistry}, volume = {15}, number = {3}, year = {1983}, note = {//NMSU//NONE, LTER//}, month = {1983}, pages = {303-309}, abstract = {

Soil respiration of a desert soil was measured at the New Mexico State University Ranch in Southern New Mexico. Respiration rates were highest during late July and August after summer rains. Soil respiration data were used to estimate soil organic matter turnover which was 54 yr using summer data and 20 yr using both summer and winter data. The long turnover estimate for summer measurements resulted from temperatures above optimum in June and July. Diurnal soil respiration was also measured after a simulated 2.54 cm rain event. For both wetted and dry soils, temperature controlled the patterns of soil respiration with an optimum of near 41 C. Activation energy values decreased form 84.91 to 39.5 kJ mol-1 when the soil was wetted. A light-dark container method was tested as a possible means of estimated algal uptake of CO2, however, the method was not feasible for desert soils.

}, keywords = {article, articles, decomposition,organic matter turnover, journal, journals, rangeland, soil respiration, soil, organic matter turnover}, doi = {10.1016/0038-0717(83)90075-5}, url = {files/bibliography/JRN00008.pdf}, author = {L. W. Parker and J.R. Miller and Yosef Steinberger and Walter G. Whitford} } @article {51966, title = {Structure and function of North America desert grassland ecosystems}, year = {1983}, month = {July 1983}, pages = {298 }, address = {Las Cruces}, abstract = {

It became obvious during the preparation of this volume that many gaps exist in our knowledge of Desert Grassland ecosystems. The research conducted under the Grassland Biome of the International Biological Program, and summarized in this volume, barely scratched the surface. This volume, however, presents some new information and unique analysis for desert grasslands.

}, url = {/files/bibliography/245.pdf}, author = {Pieper, Rex D. and Anway, J.C. and M. A. Ellstrom and C.H. Herbel and Packard, R. L. and Stuart L. Pimm and Ralph J. Raitt and E.E. Staffeldt and Watts, J. G.} } @proceedings {51992, title = {Seasonal grazing of semidesert tobosa rangeland in southern New Mexico}, year = {1982}, month = {November 10-12, }, pages = {137-142}, address = {College Station, TX}, abstract = {Research objectives included: (1) Evaluate tobosa (Hilaria mutica) managed under seasonal-continuous stocking with a low stock density and seasonal rotation stocking with a high stock density in arid southern New Mexico. (2) Characterize the average daily weight change in replacement Bos taurus and Bos taurus,Bos indicus crossbred replacement heifers managed under low stock density and high stock density grazing management.}, keywords = {rangeland, seasonal grazing, semideseret, tobosa}, url = {/files/bibliography/211.pdf}, author = {D.M. Anderson} } @article {51996, title = {Summer and Fall Diets of Blacktailed Jackrabbits on Semidesert Rangeland}, number = {Research Report 476}, year = {1982}, month = {1982}, pages = {19}, institution = {New Mexico State University}, address = {Las Cruces}, abstract = {

The black-tailed jackrabbit (Lepus californicus) is one of the most widespread herbivores on western rangelands. It occurs from Canada to northern Mexico and from the west coast to the Central Plains of the U.S. (Hansen and Flinders, 1969). Apparently they favor an open or semi-open habitat because they depend on speed and distance to escape predators (Ingles, 1947; Leopold, 1959).

Since black-tailed jackrabbits are so widely distributed, they must be able to utilize a wide array of food sources. Thus food-habit studies conducted in one area may not apply to another. In previous studies, jackrabbits and cattle exhibited considerable dietary overlap (Hansen and Flinders, 1969; Sparks, 1968; and Uresk, 1978). Griffing and Davis (1976) reported on gross examination of stomach contents and feeding behavior of blacktailed jackrabbits in southeastern New Mexico, but not on detailed food habits. However, information on food habits of the black-tailed jackrabbit in New Mexico is lacking but is needed for proper management of these herbivores.

The objective of this study was to compare botanical {\textperiodcentered} composition of black-tailed jackrabbit diets from different vegetational types, using microhistological analysis of fecal pellets.

}, keywords = {Agricultural Experiment Station, blacktailed, diets, jackrabbits, New Mexico, research report}, url = {/files/bibliography/213.pdf}, author = {Dabo, Sira-Mady and Pieper, Rex D. and Reldon F. Beck and Southward, G.M.} } @article {52009, title = {Seasonal suitability grazing in the western United States}, journal = {Rangelands}, volume = {4}, year = {1982}, month = {1982}, pages = {252-255}, abstract = {

A recent review of grazing system literature in the Journal of \ Range \ Management \ (32:250) by A. Van Poolen \ and J. Lacey \ shows\  that a stocking \ rate reduction will generally contribute more to range improvement \ than implementation of a specialized grazing \ system. However, one type of spe-cialized grazing system that can lead to improvement in livestock \ production and range vegetation under certain conditions was not considered. \ Kenneth Valentine of New Mexico \ State University \ (JRM, 1967, 20:395) first described this \ system, and \ named it \ "Seasonal Suitability" grazing. Similar \ principles apply to the use of complementary tame pastures in conjunction with native range.

}, url = {/files/bibliography/220.pdf}, author = {Jerry L. Holechek and C.H. Herbel} } @article {52016, title = {Seasonal activity of tenebrionid beetles in New Mexico mesquite dunes}, journal = {Southwest National}, volume = {27}, number = {3}, year = {1982}, note = {//USDA//NONE//}, month = {1982}, pages = {305-308}, abstract = {Nine species of tenebrionid beetles in four genera, Eleodes, Embaphion, Eusattus, and Glyptasida, were collected in pitfall traps throughout an annual cycle at two sites in a mesquite dune habitat on the Jornada Experimental Range (USDA) north of Las Cruces, New Mexico. These beetles were shown to have seasonal activity patterns which were similar at both sites and which differed significantly between most species.}, keywords = {article, articles, beetle, tenebrionid, herbicide, "2,4,5-T", tenebrionid beetles, insect, tenebrionid beetles, journal, journals, mesquite dunes,tenebrionid beetles}, author = {D. Richman and E.W. Huddleston and Melchor Ortiz} } @mastersthesis {52020, title = {Some effects of clipping on the developmental morphology of mesa dropseed (Sporobolus flexuosus (Thurb.) Rhyb.)}, year = {1982}, note = {//??//NONE//}, month = {1982}, pages = {69}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, grass,mesa dropseed,Sporobolus, Sporobolus,clipping effects, theses, thesis}, author = {Tarassoum, T. D.} } @mastersthesis {52026, title = {Seasonal defoliation and growth responses of Muhlenbergia porteri Scribn. Ex Beal. in pure stands and in association with Larrea tridentata (DC) Coville, with emphasis on structural analysis.}, year = {1981}, note = {//NMSU//NONE//ProCite field[36]: Located in}, month = {1981}, pages = {126}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {M. porteri is an important grazing plant in southern desert lands. The association with L. tridentata is of special intrest to range management, as it has been postulated that M. porteri competes with L. tridentata. The objective of this study was to determine the response of these two species, utilizing structural data...In 1978 at the three phenological stages, boot, flower and dormancy, 13 variables were measured. In 1979, 19 variables were measured at the vegetative, boot, and flowering phenological stages of M.porteri, each stage had four groups of clipping treatments, initiated in 1978. Through mulitvariate discriminant anlaysis the more important variables were selected, which assisted to classify the phenological stages of 1978 and, for 1979 variables, in the treatment indentification on the basis of morphometric measurements of M.porteri.}, keywords = {dissertation, dissertations, grass, Muhlenbergia, grass,defoliation, grass,growth response, Larrea, grass association, Muhlenbergia, defoliation, Muhlenbergia, phenology, Muhlenbergia, shrub assocciation, Muhlenbergia,growth response, shrub, Larrea, theses, thesis}, author = {Almeida-Martinez, Manuel Ricardo} } @mastersthesis {52030, title = {Systematic and ecological studies of the Apodemia mormo complex (Lepidoptera: Riodinidae) in southern Arizona and southern New Mexico}, year = {1981}, note = {//LOCAL//NONE//}, month = {1981}, pages = {83}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Population samples of the polytypic riodinid butterfly Apodemia mormo from the southwestern United States and northern Mexico were studied to determine the distribution of phenotypic variation. In all, 1,813 specimens from 103 locales were examined; 464 specimens were used in cluster and discriminant analysis procedures. The study revealed a highly diverse assemblage consisting of latitudinal and attitudinal clines, polytopic races, complex intergrade zones, and extensive individual variation. Variation present in the study area (southern Arizona to western Texas) was compared with variation patterns on California, Colorado, and Baja California populations. Intergrade zones are interpreted as possibly the result of local intermediacy in selective factors rather than physical contact of adjoining races. Gene flow appears to be greatly restricted among neighboring populations in the region of intergradation. Variation in A. mormo may be determined by such factors as thermoregulation, cryptic coloration, and foodplant associations. The role of historical selective factors is also acknowledged, as is the possibly nonadaptative nature of the color patterns due to pleiotropy. The polytopic nature of the insect, in which distant populations produce the some phenotypes, is evidence against the complex consisting of more than one species throughout most of the range. In a few cases, it is possible that local temporally or ecologically isolated populations (such as those seperated by foodplant preference) may be reproductively isolated species or sibling species.}, keywords = {Apodemia,ecology of, Apodemia,phenotypic variation, butterfly,SEE , dissertation, dissertations, invertebrate, Apodemia,systematics, Lepidoptera,Apodemia, theses, thesis}, author = {Gregory S. Forbes} } @mastersthesis {52036, title = {Soil movement and vegetational changes over a forty-five year period in south-central New Mexico}, year = {1981}, note = {//USDA//NONE//}, month = {1981}, pages = {108}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {The purpose of this study was to evaluate the vegetational changes and soil movement which accompanied the processes of mesquite (Prosopis glandulosa) spread and dune building on the Jornada Experimental Range in southwestern New Mexico. Two 259 ha grid systems and two belt transects were established in the mid-1930{\textquoteright}s. Both grid systems and transects were referenced to soil surface levels at that time and the transects were mapped in detail showing perennial plant species present and dune profiles and lateral extent. Using this early data for comparison, soil surface levels, plant species, and mesquite dune data were gathered in 1980. The results showed that a substantial amount of soil movement had occurred on all areas. While one area gained soil over the 45-year period, all other sites lost soil. An equation developed to determine the constitution of the loss showed that it was mostly in the fine sand and silt fractions.}, keywords = {Bouteloua, dissertation, dissertations, eolian, process, landscape,vegetation change, Prosopis, dune formation, Prosopis, encroachment, shrub encroachment, soil, movement, soil,dune development, Sporobolus, theses, thesis, vegetation, changes in, Xanthocephalum}, author = {J.T. Hennessy} } @book {52043, title = {Short-term water and energy flow in arid ecosystems}, series = {Arid Land Ecosystems: Structure, Function and Management}, volume = {Volume 2}, number = {17}, year = {1981}, note = {//NMSU//US-IBP//ProCite field[6]: InProCite field[32]: International Biological Program}, month = {1981}, pages = {271-299}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, address = {Great Britain}, abstract = {

The objective of this chapter is to discuss the dynamic behavior of the biotic components of arid ecosystems in relation to water and energy flow between and within seasons. The growth responses of the different plant species occupying adjacent ecosystems in a watershed will be related to water availability and to heat energy levels. Growth and behavioral responses of groups of animals with contrasting adaptations to changing conditions of food and water availability will be discussed. Plant and animal litter redistribution and decomposition patterns will be discussed with respect to patterns of energy flow and climatic variation. Finally, general conclusions about desert ecosystem dynamics with respect to short-term water and energy flow will be stated.

}, keywords = {arid ecosystem, water \& energy flow, arthropod, bird, book, books, chapter, chapters, decomposition,ecosystem dynamics, ecosystem dynamics, abiotic factors, ecosystem dynamics, biotic responses, ecosystem dynamics, energy flow, ecosystem dynamics, water, energy flow, insect, microarthropod, plant, ecosystem dynamics, precipitation,ecosystem dynamics, predator, report, reports, rodent, seed consumer, water}, url = {files/bibliography/81-AridLand-Whitford.pdf}, author = {J. Ludwig and Walter G. Whitford}, editor = {D. W. Goodall and Perry, R. A. and Howes, K. M. W.} } @article {52071, title = {A single bayonet gate for trapping range cattle}, journal = {Journal of Range Management}, volume = {33}, number = {4}, year = {1980}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {July 1, 1980}, pages = {316-317}, abstract = {Single bayonet gates are effective in trapping range cattle inside a corral in which water is located. These gates require less time to construct than similar-size double-bayonet gates and contain about half as much material. Labor costs are second only to land charges in the high cost of today{\textquoteright}s livestock production (Maddox 1970). When labor-saving equipment is added to a livestock enterprise, personnel are released to concentrate efforts on other areas of the ranching operation. The efficiency of labor use is increased if animal behavior is considered in livestock management decisions. By capitalizing on an animal{\textquoteright}s need for water, one can trap cattle with a single bayonet gate, thus reducing the stress, time, and effort involved in conventional roundups. The technique involves setting up a one-way maze in a corral at which the animals will water. If all other gates into the corral are closed and a single bayonet gate is located at the entrance, cattle can be trapped as they enter to drink water. Double bayonet gates (Low and Hodder, 1976), triggers [Ward, 1958; Freeman (no date); Welchart and Gray (no date); Hughes, 1978], or crushes (Ernst, 1977), as they have been called, are not new to the livestock industry. The single-bayonet gate described in this paper requires less material for construction than double bayonet gates, yet does not reduce the gate{\textquoteright}s ability to trap and hold animals in a corral.}, keywords = {increased efficiency, range cattle, single bayonet gates}, url = {/files/bibliography/177.pdf}, author = {D.M. Anderson and J. N. Smith} } @booklet {52076, title = {Soil Survey of Dona Ana County Area, New Mexico}, year = {1980}, note = {//LOCAL//NONE//}, month = {1980}, pages = {177}, publisher = {USDA, Soil Conservation Service}, type = {pp}, abstract = {This soil survey contains much information useful in land-planning programs in the Dona Ana County Area. Of prime importance are the predictions of soil behavior for selected land uses. Also highlighted are limitations or hazards to land uses that are inherent in the soil, improvements needed to overcome these limitations, and the impact that selected land uses will have on the environment....These and many other soil properties that affect land use are described in this soil survey. Broad areas of soils are shown on the general soil map; the location of each kind of soil is shown on detailed soil maps. Each kind of soil in the survey area is described, and much information is given about each soil for specific uses. Additional information or asssistance in using this publication can be obtained from the local office of the Soil Conservation Service or the Cooperative Extension Service.}, keywords = {book, books, chapter, chapters, geomorphology, Dona Ana County, report, reports, soil geomorphology, soil survey, Dona Ana County}, author = {Bulloch, H. Edward , Jr. and Raymond E. Neher} } @proceedings {52092, title = {A simulation model of the productivity of spanish bayonet, Yucca baccata Torr.}, year = {1980}, note = {//LOCAL//NONE//ProCite field[6]: In}, month = {1980}, pages = {51-68}, publisher = {Centro de Investigacion en Quimica Aplicada}, abstract = {In a previous study on the amounts of energy accumulated by Yucca baccata low photosynthetic rates were found using laboratory apparatus. Our current studies indicate higher rates using natural levels of irradiance in the field. Our current studies also have characterized a CAM metabolism in Y. baccata and Y. torreyi, but a C3 pathway in Y. elata. An earlier, preliminary simulation model of Y. baccata productivity did not include the mechanism of CAM. Our new simulation model presented here includes the CAM pathway and gives realistic predictions of productivity and carbon allocation in Y. baccata under different environmental conditions.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, model, growth, Yucca, proceeding, proceedings, productivity, Yucca, spanish bayonet, SEE 137Cs appears to be feasible as a means of pathogen reduction in large-scale operations. Since 1975 New Mexico State University has evaluated dried, "radicized" solids from raw sewage (primary sludge) as a prospective supplemental feedstuff for ruminants (cattle, sheep) subsisting on poor-quality roughage feeds. Our published reports and unpublished data support the view that products derived from raw sewage could provide substantial nutritive value to ruminant animals without necessarily incurring intolerable risk to the animals or the human food chain, especially if such products are used only periodically in the maintenance of breeding herds and/or in the early "background" programs of young ruminants destined for slaughter much later. Objectives of experiments reported here were to demonstrate under practical conditions the benefits from an experimental feed supplement (containing 62\% dried, irradiated sewage solids) for gestating-lactating beef cows grazing dormant forage on semidesert rangeland and to assess, under extreme conditions, the accumulation of heavy metals and/or refractory organic compounds (toxicants) in tissues of cattle fed sewage solids for almost 3 months.}, keywords = {forage, rangeland, ruminants, sewage solids, supplemental feed}, url = {/files/bibliography/185.pdf}, author = {Geoffrey Smith and H.E. Kiesling and C.H. Herbel and Ray, E.E. and Trujillo, P.A. and Orcasberro, R. and Sivinski, J. S.} } @article {52113, title = {Surface litter breakdown in a Chihuahuan Desert ecosystem}, journal = {Pedobiologia}, volume = {20}, year = {1980}, note = {//NMSU//NONE//}, month = {1980}, pages = {243-245}, abstract = {In a study of distribution patterns of litter and microarthropods we (Santos et al. 1978) found that microarthropod density was highly correlated with amount of surface litter in a Chihuahuan desert creosotebush community. Based on that relationship we hypothesized that the rate of litter decomposition would vary directly with the amount of surface litter present. This paper reports on experiments designed to test that hypothesis and to examine the relationship between quantity of surface litter, microarthropod density and plant growth.}, keywords = {article, articles, decomposition, microarthropod, decomposition,litter, journal, journals, microarthropod, decomposition, pesticide, Chlordane}, author = {Walter G. Whitford and Bryant, Martha and George Ettershank and Jennifer Ettershank and Perseu F. Santos} } @article {52119, title = {Some effects of soil-moisture availability on above-ground production and reproductive allocation in Larrea tridentata (DC) Cov}, journal = {Oecologia}, volume = {40}, year = {1979}, note = {//NMSU//US-IBP//}, month = {1979}, pages = {113-123}, abstract = {Data from the US/IBP Desert Biome validation studies indicate that above-ground production and biomass allocated to reproduction in Larrea tridentata vary from one year to another depending upon the timing and extent soil-moisture availability. In an attempt to verify these observations and determine to what extent water availability can affect total above-ground production and reproductive allocation in this widely distributed warm desert shrub, a series of soil-moisture augmentation experiments were conducted. High levels of soil moisture had a greater effect on reproductive allocation than on total above-ground production. Enhanced soil moisture during the period of active growth increased total above-ground production and reduced the percentage of biomass allocated to reproduction. Enhanced soil moisture during the normal periods of little or no growth did not increase total above-ground production.}, keywords = {article, articles, journal, journals, Larrea, reproduction, Larrea, soil moisture, Larrea,productivity, plant,Larrea tridentata}, author = {Gary L. Cunningham and J. P. Syvertsen and J. F. Reynolds and Willson, J. M.} } @conference {52135, title = {Sewage solids as supplemental feed for beef cows grazing dormant rangeland forage}, booktitle = {American Society for Animal Science Conference}, year = {1979}, month = {1979}, pages = {178}, keywords = {dormant rangeland forage, sewage solids, supplemental feed}, author = {Geoffrey Smith and H.E. Kiesling and Orcasberro, R. and Ray, E.E. and C.H. Herbel} } @mastersthesis {52138, title = {Seasonal, interspecific, and intraspecific variation in the mobbing response of desert birds to different predator types}, year = {1979}, note = {//NMSU//US-IBP//}, month = {1979}, pages = {65}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {This field study of avian mobbing behavior has demonstrated a higher seasonality of the mobbing response than that found in other studies. The response is limited to the breeding season, suggesting that mobbing is primarily a nest defense. The use of several different predators as stimulus objects demonstrated a marked difference in the level and kind of response received by different predators. The level of the response is directly correlated with the degree of danger posed by the predator, as shown by food habits.}, keywords = {behavior, mobbing response, bird,behavior, bird,mobbing behavior, bird,predation, dissertation, dissertations, predation, of birds, theses, thesis}, author = {Wahl, Charles Rex} } @mastersthesis {52142, title = {Species diversity of nocturnal rodents in disturbed desert-grassland habitats}, year = {1978}, note = {//USDA//NONE//}, month = {1978}, pages = {80}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {Nocturnal rodent communities were sampled by live-trapping seasonally on seven sites on sandy soils on the USDA Jornada Experimental Range, Dona Ana County, New Mexico during 1975 and 1976. An attempt was made to contrast three current hypotheses concerning those factors which determine species diversity of small mammals. According to these, diversity should be higher in habitats which have 1) greater amounts of predictable precipitation and resources, 2) greater structural complexity, or 3) more mature successful status (i.e., less disturbed)... It was predicted that climax grassland habitats would support greater rodent species diversity than dis-climax shrublands. This was generally true, but substantial temporal variations in diversity weakened tests for statistical significance.}, keywords = {community, rodent, dissertation, dissertations, disturbance, rodent, grassland, disturbed habitats, rodent, disturbed habitats, rodent, nocturnal, rodent, species diversity, species diversity,rodents, theses, thesis}, author = {M. S. Alberico} } @article {52144, title = {Seasonal water balance in Orthoporus ornatus, a desert millipede}, journal = {Ecology}, volume = {59}, year = {1978}, note = {//??//NONE//}, month = {1978}, pages = {996-1004}, keywords = {article, articles, invertebrate,millipedes, journal, journals, metabolism,millipedes, millipede,metabolism, Orthoporus,metabolism}, author = {Crawford, C. S.} } @article {52145, title = {A simulation model of primary production and carbon allocation in the creosotebush (Larrea tridentata [DC.] Cov.)}, journal = {Ecology}, volume = {59}, number = {1}, year = {1978}, note = {//NMSU//US-IBP//}, month = {1978}, pages = {37-52}, abstract = {A preliminary simulation model of primary productivity and carbon allocation in creosotebush (Larrea tridentata [DC] Cov.) is described. The model utilizes a systems approach in which movement of assimilate within the plant is in response to changes in source-sink strengths of leaves, stems, roots, early reproductive buds, maturing reproductive buds, flowers, and fruits. Two distinct compartments are defined per organ or developmental stage to separate assimilate into a pool fraction (labile or translocatable) and a structural fraction (nonlabile). The changes in magnitude (within upper and lower limits) of a pool compartment during the course of a simulation (i.e., growth and development of the plant) are a function of the rates of maintenance respiration and growth as well as a priority scheme governing allocation of assimilates; the increases and decreases in dry weight of a structural compartment are a function of aging and the magnitude of its associated pool (which determines structural growth and physiological death). A 1-yr simulation of a hypothetical Larrea plant shows that the model exhibits a reasonable behavior, although no validation is attempted at this stage in its development. The heuristic value of the model is illustrated in the sensitivity analysis, which shows the need for detailed knowledge of "priority" carbon movement during both vegetative and reproductive growth periods, the importance of substrate controlled respiration rates, and the need for further studies of the dynamics of labile pools in the plant. The model has been an excellant tool in our initial attempt to integrate the voluminous information on Larrea into a complete functional description of the autecology of the species. Further refinement of this model, as data from our current research and that of other investigators become available, should lead us to a better understanding of the ecological role of Larrea in desert ecosystems.}, keywords = {article, articles, creosotebush,also SEE , journal, journals, Larrea, carbon allocation, model,carbon allocation,Larrea, model,primary production,Larrea, primary production,Larrea, shrub, Larrea}, author = {Gary L. Cunningham and J. F. Reynolds} } @article {52164, title = {Spatial distribution of litter and microarthropods in a Chihuahuan desert ecosystem}, journal = {Journal of Arid Environments}, volume = {1}, year = {1978}, note = {//NMSU//US-IBP//}, month = {1978}, pages = {41-48}, abstract = {

Plant litter accumulated along the edges of small water courses where plants caused formation of eddy currents during heavy rains. Only small amounts of plant litter accumulated under shrubs on sloping erosional areas when compared to shrubs on flat areas. Microarthropod densities ranged from 146 .m-2 in unvegetated areas to 3103 .m-2 under shrubs in small water courses. Microarthropod density was directly correlated with amount of surface litter (r= 0.987). Prostigmatid mites of the family Nanorchestidae were found in all habitats and Prostigmatids were the most numerous Acarina in all but one area. Collembola were found only in unvegetated areas of a large wash.

}, keywords = {acarina, SEE , article, articles, collembola, also SEE , journal, journals, litter, spatial distribution, litter,microarthropods, microarthropod, Collembola, microarthropod, litter, microarthropod, mites, microarthropod, spatial distribution, mite, spatial distribution, termite}, doi = {10.1016/S0140-1963(18)31753-1}, url = {files/bibliography/78-Journal of Arid Environments-Whitford.pdf}, author = {Perseu F. Santos and Elaine DePree and Walter G. Whitford} } @article {52173, title = {Structure and seasonal activity of Chihuahuan Desert ant communities}, journal = {Insectes Sociaux}, volume = {25}, number = {1}, year = {1978}, note = {//NMSU//US-IBP//}, month = {1978}, pages = {79-88}, abstract = {

In a desert area with abundant annual plants the largest feeding guild was grammivores (nine species). In an area with few annual plants, the largest feeding guild was omnivores (eight species). Within a guild there is little overlap in body length of workers. Species in which there was overlap in body length of workers exhibited marked differences in diet and seasonal activity. Variation in precipitation and productivity between years resulted in differences in seasonal activity, hence considerable variation in the structure of the ant community through time.

}, keywords = {ant community,behavior, article, articles, community, ant, behavior, gramnivore,ant community, journal, journals, omnivores,ant community}, issn = {0020-1812}, doi = {10.1007/BF02224487}, author = {Walter G. Whitford} } @article {52177, title = {The structure and distribution of Larrea communities}, year = {1977}, note = {//OTHER//US-IBP//ProCite field[6]: In}, month = {1977}, pages = {227-251}, institution = {Dowden Hutchinson \& Ross Publications}, abstract = {Species of Larrea so thoroughly dominated the warm deserts of North and South America that if we were truly to discuss Larrea communities in this chapter, we would find doing so a lengthy and difficult task. Such a task would also be beyond the basic objectives of this volume. Our purpose in this chapter is to review recent IBP research. Vegetation on IBP study sites is emphasized. The IBP data are supplemented with data from other, earlier studies only in a limited number of instances.}, keywords = {book, books, chapter, chapters, community,Larrea, Larrea, community, Mojave Desert,Larrea community, report, reports, shrub, Ambrosia, shrub, Larrea}, author = {Barbour, M. G. and MacMahon, J. A. and Bamberg, S. A. and J. Ludwig}, editor = {Creosotebush - Biology and Chemistry of Larrea in New World Desert} } @conference {52191, title = {Solar radiation as a detrimental factor to photosynthesis and growth in Rumex patientia L.}, booktitle = {30th Annual Meeting, Society for Range Management}, year = {1977}, month = {1977}, pages = {30}, keywords = {photosynthesis, Rumex patientia, solar radiation}, author = {Sisson, W.B.} } @article {52200, title = {Seasonal and yearly fluctuations in Chihuahuan Desert lizard communities}, journal = {Herpetologica}, volume = {33}, year = {1977}, note = {//NMSU//NONE//}, month = {1977}, pages = {54-65}, abstract = {

Two lizard communities, each consisting of seven residents plus several transient or immigrant species, were studied between 1970 and 1975 on a Chihuahuan desert watershed. Lizard species diversity was correlated with the previous 2 yr rainfall. H\&$\#$39; varied between 1.28 and 1.91. The change in diversity in these lizard communities resulted from the influx of transient species and increase in numbers of resident species during a 2-yr wet period and the reverse during drought periods. The influx of transients and immigrants appeared to be related to the expansion of suitable habitat and the proximity to a source area for immigrants. The density of adult Cnemidophorus tigris nearly doubled in 1 yr which was attributed to above average overwinter survival of hatchlings. Seasonal activity periods of adults and hatchlings were longer during dry years than wet years. During wet years adults and juveniles of most species exhibited allochronic activity. Densities of most resident species varied directly with changes in productivity and relative abundance and activity of arthropods. Sceloporus magister numbers remained relatively constant over the 5 yr and this appeared to be related to availability of suitable habitat.

}, keywords = {article, articles, community, lizard, journal, journals, lizard, community, lizard,Cnemidophorus, lizard,Sceloporus}, url = {files/bibliography/77-Herpetologica-Whitford.pdf}, author = {Walter G. Whitford and Creusere, F. Michael} } @mastersthesis {52204, title = {Summer activity cycles of Urosaurus ornatus in field and laboratory}, year = {1976}, note = {//NMSU//NONE//}, month = {1976}, pages = {30}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {The behavioral activity of Urosaurus orantus was studied in the field and laboratory. An ethogram was made from field observations. The percent of time in which the major behavioral patterns were performed during each hour of the day was also recorded. Daily cycles in the time at which these behaviors occurred in the field were found. Territorial encounters only occurred before 1230 hr. At 1230 hr simultaneous peaks in spontaneous pushups and courtship activity occurred. The cyclic occurrence of these behaviors can be related to both environmental factors and laboratory activity cycles. In the laboratory, a 12 hr LD cycle was imposed upon different groups of male and female U. orantus at constant temperatures of 23 degrees Celsius or 34 degrees Celsius, most locomotory activity occurred during the midday hours. At 34 degrees Celsius, activity was shifted towards early morning. Males and females exhibited equal levels of activity at 23 degrees Celsius, while at 34 degrees Celsius males were twice as active as females.}, keywords = {behavior, Urosaurus, dissertation, dissertations, lizard, Urosaurus, lizard,behavior, lizard,tree lizard, Urosaurus, reptile, also SEE , theses, thesis, Urosaurus,behavior}, author = {Delahunt, Regina Anne} } @article {52212, title = {Spatial and temporal variations in Chihuahuan desert ant faunas}, journal = {The Southwestern Naturalist}, volume = {21}, number = {1}, year = {1976}, note = {//NMSU//US-IBP//}, month = {1976}, pages = {1-8}, abstract = {

Estimates of colony densities of active colonies of ants were made at frequent intervals throughout the year in two Chihuahuan desert communities: a creosotebush bajada and mesquite-mormon tea playas fringe community. Densities of harvester ants, Pogonomyrmex, were higher on the playa site; and seed harvesters, Pheidole, were higher on the bajada. Some ant species exhibited specific habitat requirements with regard to soil type and/or plant cover: Formica perpilosa, Pogonomyrex imbericulus, Trachymyrmex smithi neomexicanus. Other species were more generally distributed. Two congeneric species pairs exhibited differences in seasonal activities suggesting competitive interactions. Peak densities of active ant colonies exceeded 4,000 colonies ha-1 on the playa and 2.000 colonies ha-1 on the bajada.

}, keywords = {ant, Conomyrma, ant, Formica, ant, Iridomyrmex, ant, Myrmecocystus, ant, Novomessor, ant, Pheidole, ant, Pogonomyrmex, ant, Trachymyrmex, ant,spatial variations, ant,temporal variations, article, articles, journal, journals}, doi = {10.2307/3670317}, url = {files/bibliography/76-TheSWNat.-Whitford.pdf}, author = {Aileen Schumacher and Walter G. Whitford} } @article {52214, title = {Seasonal activity and water loss relationships in four species of Eleodes (Coleoptera: Tenebrionidae)}, journal = {The Southwestern Entomologist}, volume = {1}, number = {4}, year = {1976}, note = {//NMSU//US-IBP//}, month = {1976}, pages = {161-163}, abstract = {

Four Chihuahuan desert species of Eleodes in southern New Mexico show seasonal activity patterns that are consistent with their relative abilities to conserve water. Eleodestenuipes and Eleodes gracilis, 2 species with lowest rates of water loss, exhibited peak activity in July and August. Eleodes longicollis and Eleodes sponsa, which have the highest water loss rates, show the greatest activity in the spring and autumn.

}, keywords = {article, articles, insect,Eleodes,activity, insect,Eleodes,water loss, journal, journals}, url = {files/bibliography/76-SWNat-Whitford.pdf}, author = {W. E. Smith and Walter G. Whitford} } @article {52217, title = {Semiarid rangeland treatments and surface runoff}, journal = {Journal of Range Management}, volume = {29}, number = {3}, year = {1976}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {May 1, 1976}, pages = {251-255}, abstract = {Effects of pitting and rootplowing on surface runoff were determined on a desert shrub range in southeastern Arizona, and the time-dependent changes in the soil surface characteristics resulting from these practices were studied. Additional detention storage was provided by increased roughness in microtopography, thereby decreasing surface runoff when compared to the control. Rock and gravel were negatively correlated with surface runoff. Combining the two parameters showed a significant reduction in surface runoff. Increases in runoff were associated with exposed soil. Crown cover significantly reduced runoff. Litter was not significant in the reduction of runoff. Regulation of surface runoff is important for on-site rangeland improvements, as well as reducing sediment yields.}, url = {/files/bibliography/157.pdf}, author = {J.M. Tromble} } @article {52218, title = {Some ecological relationships between creosotebush and bush muhly}, journal = {Journal of Range Management}, volume = {29}, number = {6}, year = {1976}, note = {//NMSU//NONE//}, month = {1976}, pages = {427-475}, abstract = {Some ecological relations between creosotebush and bush muhly were observed and measured to determine the influence of bush muhly on creosotebush environment and vigor when the bush muhly is growing within the creosotebush canopy. Bush muhly growing within the creosotebush canopy significantly reduced the light intensity reaching the lower limbs of creosotebush. Shade screens sued for simulating bush muhly shading did not significantly reduce the light reaching the creosotebushes but still appeared to influence the new growth of creosotebush leaves. Evidently, surface reflection under the screens still permitted sufficient light for some plant growth. No new basal stem growth was observed in creosotebushes where bush muhly was removed after occupying more than half of the aerial space of the creosotebush. There were more dead stems (50\%) in creosotebushes growing with bush muhly present than in those without (20\%). The amount of moisture in leaves and stems of creosotebush was significantly less when bush muhly was present.}, keywords = {article, articles, community, shrub-grass interaction, journal, journals, Larrea,grass interaction, Muhlenbergia,shrub interaction, productivity, Larrea, productivity,Muhlenbergia}, author = {Welsh, Richard G. and Reldon F. Beck} } @article {52224, title = {Somatic crossing over as a cause of intergenome translocations in haploid cotton}, journal = {The Journal of Heredity}, volume = {66}, year = {1975}, month = {1975}, pages = {277-280}, keywords = {cotton, haploid, intergenome, somatic}, url = {/files/bibliography/99-006.pdf}, author = {J.R. Barrow and M.P. Dunford} } @mastersthesis {52229, title = {Some reproductive aspects of three Chihuahuan Desert Nyctaginaceae}, year = {1975}, note = {//??//NONE//}, month = {1975}, pages = {42}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexcio}, abstract = {The distribution of all three of the Nyctagineaceae species studied, Ammocodon chenopodiodes, Selinocarpus lanceolatus and Acleisanthes longiflora, is centered in the Chihuahuan Desert. All three genera regularly produce cleistogamous flowers, flowers in which the corolla does not open, but which, nevertheless, produce fruit and seeds as a result of self-fertilization. The relative frequency of cleistogamous and chasmogamous flowers (open flowers capable of outcrossing) is examined. Acleisanthes and Selinocarpus shift from a high percentage of cleistogamous flowers in late spring to a high percentage of chasmogamous flowers in summer. This shift appears to be co-ordinated with the onset of the summer rains and possibly with the presence of their pollinator, the hawk moth. The proportion of chasmogamous flowers on Ammocodon plants changes throughout a growing season, although the change is not neccessarily the same in all populations. The absence of a distinct shift in the proportion of chasmogamy in Ammocodon may be due to the fact that, in comparison with the other two species, Ammocodon is pollinated by a general array of insects and therefore not dependent on a specific pollinator. Cleistogamy in all three species appears to insure seed-set, with a relatively small expenditure of energy to the plant, under conditions unsuitable for cross-pollination}, keywords = {dissertation, dissertations, Nyctaginaceae,reproduction, plant, Ammocodon, plant,Acleisanthes, plant,reproduction, plant,Selinocarpus, reproduction,Nyctaginaceae, theses, thesis}, author = {Delson, Rebecca Koskela} } @article {52241, title = {Size-biomass relations of several Chihuahuan Desert shrubs}, journal = {The American Midland Naturalist}, volume = {94}, number = {2}, year = {1975}, note = {//NMSU//US-IBP//}, month = {1975}, pages = {451-461}, abstract = {Rapid, nondestructive methods are needed to quantify plant biomass dynamics. Methods known as dimension analysis can be used to establish regression relationships between plant biomass and estimate the dry weight of foliage, living and dead stems and roots from canopy area and volume for eight desert shrubs. The results show that volume and canopy area are generally suitable estimators. Regression equations developed for Larrea tridentata compare favorably with equations in similar studies in Arizona and Nevada, suggesting that our results might be applicable in other desert regions, at least for shrubs with well-defined growth forms. Other considerations when using these techniques are discussed.}, keywords = {article, articles, Ephedra, biomass, Flourensia, biomass, journal, journals, Larrea, biomass, method, shrub biomass, Prosopis, biomass, shrub, biomass, shrub, Larrea, Xanthocephalum, biomass, Yucca, biomass, Zinnia, biomass}, author = {J. Ludwig and J. F. Reynolds and P. D. Whitson} } @article {52253, title = {Studies on wood borers, girdlers, and seed predators of mesquite}, year = {1975}, note = {//??//US-IBP//}, month = {1975}, pages = {15-21}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {book, books, chapter, chapters, girdlers, Prosopis, mesquite, plant production,Prosopis, Prosopis,girdlers, Prosopis,seed predators, Prosopis,wood borers, report, reports, seed predators, wood borers}, isbn = {Research Memorandum 75-26}, author = {Walter G. Whitford and R. K. Johnson and D. J. DePree} } @article {JRN54836, title = {Somatic crossing over as a cause of chromosome multivalents in cotton}, journal = {Journal of Heredity}, volume = {65}, year = {1974}, month = {1974}, pages = {3-7}, chapter = {3}, abstract = {

Occasional somatic pairing of homologous chromosomes was observed in some plants and animals shortly after the turn of the century. There have been many other examples of pairing in succeeding years; where genetic markers were available for analysis, theory have provided evidence of somatic recombination. Stern19 observed single and twin spots of homozygous somatic tissue on wild-type background of Drosophilia heterozygous for specific marker genes. He established that somatic crossing over occurred in the four-strand stage and was genetically equivalent to meiotic crossing over. Jones12 suggested that spotting observed in corn tissues could be explained by somatic paring and crossing over. Vig22 reported genetic evidence of somatic crossing over as a course of twin spot in soybeans, heterozygous for incompletely doming gene Y11 for foliage color. He noted increased frequency of twin spots after treatment with chemicals known to allow rejoining of chromosomes. We2 observed twin spots in the leaves of homozygous cotton plants and considered somatic crossing over between homoeologous chromosomes as a more plausible explanations than somatic nondisjunction. In the early 1950{\textquoteright}s, geneticists working with several genera of imperfect fungi reported genetic recombination, concluding that somatic pairing of homologous chromosomes must occur.\  Westergaard concluded "that somatic crossing over that results in genetic recombination can only occur in cells having genetic recombination can only occur in cell having somatic pairing" (see Brown5 p,61). Gruberg9 stated "the cumulative weight of evidence makes a strong case for the existence of somatic crossing over in laboratory rodents." Holliday11 determined that somatic pairing of homologues occurs during interphase of the same time DNA is replicated.

}, doi = {10.1093/oxfordjournals.jhered.a108451}, author = {J.R. Barrow and M.P. Dunford} } @mastersthesis {52274, title = {Some effects of carbamate insecticide on primary producers in a desert grassland ecosystem}, year = {1974}, note = {//NMSU//NONE//}, month = {1974}, pages = {24}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Field and greenhouse studies were undertaken to determine some effects of a carbamate insecticide on primary producers in a desert grassland ecosystem. A 2500 m2 field area was sprayed with Sevin and periodically sampled over a period of one year to obtain density, cover and biomass data. These results were compared to an untreated control area. Over the study period, no significant differences developed in the above parameters between treatment and control areas. In the greenhouse, field transplanted Boutelua eriopoda plants received various concentrations of insecticide and were sampled over a period equivalent to the growing season for vegetative and reproductive biomass. No significant differences developed among the various treatments and control. The only study that produced significantly different results was the germination experiment. B. eriopoda seeds were soaked in various concentrations of insecticide and allowed to germinate in moistened petri plates. The medium concentration tested, 0.01\%, produced significantly higher germination percentages than the water only control.}, keywords = {Bouteloua, germination, dissertation, dissertations, grassland, insecticide effects, insecticide, carbamate, insecticide, primary production, insecticide, Sevin, primary production, insecticide, theses, thesis}, author = {Hickman, Gary Wayne} } @article {52278, title = {Soils of New Mexico}, year = {1974}, note = {//NMSU//NONE//}, month = {1974}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, abstract = {

This publication describes the characteristics of the major soils of the state. The accompanying map groups the soils into associations of great groups within larger soil regions.

}, keywords = {book, books, chapter, chapters, geomorphology, report, reports, soil associations, soil classification, soil formation, soil, survey}, isbn = {Research Report 285}, url = {files/bibliography/NMAES 1974 RR285.pdf}, author = {Maker, H. J. and H. E. Dregne and Link, V. G. and J. U. Anderson} } @mastersthesis {52287, title = {Some factors influencing fall weights of cows under southern New Mexico range conditions}, year = {1974}, note = {//??//NONE//}, month = {1974}, pages = {42}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {cattle grazing, cattle, productivity, dissertation, dissertations, management,cattle, theses, thesis}, author = {Torres-Hernandez, Glafiro} } @article {52301, title = {Separation of treatments within a plant community based on statistical analysis of plant structural dynamics}, year = {1973}, note = {//??//US-IBP//}, month = {1973}, institution = {Colorado State University}, address = {Ft. Collins, Colorado}, keywords = {book, books, chapter, chapters, plant community, plant structural dynamics, report, reports}, isbn = {Preprint 65}, author = {Francis, R. C. and M. Campion} } @proceedings {52305, title = {Some developments related to seeding western rangelands}, volume = {Publication No. 3}, year = {1973}, month = {1973}, pages = {75-80}, address = {Madison, WI}, abstract = {Seeding Western rangelands is generally a difficult undertaking because of limiting climatic, soil and/or topographic features. The good sites with a favorable climate are in cultivated croplands. Therefore, we are trying to seed and grow range plants where even the hardiest of crop plants are not economically productive and are difficult or impossible to establish. Original plant productivity has been reduced on millions of acres of Western rangeland by past grazing abuses, brush invasion, droughts, and past attempts to cultivate nonarable land. In many areas, the degradation is so complete that seeding is required to restore at least a portion of the former productivity. It would be impossible for me to describe all the methods used in seeding Western rangelands. Rather, I will present selected results of recent studies. My colleagues in several states have provided part of this information.}, keywords = {methods, seeding, western rangelands}, url = {/files/bibliography/139.pdf}, author = {C.H. Herbel} } @mastersthesis {52309, title = {Some ecological factors influencing the distributions of two species of pocket mice (genus Perognathus)}, year = {1973}, note = {//NMSU//NONE//}, month = {1973}, pages = {81}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {Perognathus penicillatus and Perognathus intermedius were studied in several areas in Dona Ana County, New Mexico, form 1970-1972, producing comparative population data from areas of sympatry and allopatry. The effects of variations in physical environment on these two species and physiological and behavioral differences between them were studied to examine niche differences.}, keywords = {dissertation, dissertations, Perognathus, distribution, rodent, distribution, rodent, pocket mouse, Perognathus, rodent, thermoregulation, Rodentia, Perognathus, theses, thesis}, author = {Kenneth D. Hoover} } @mastersthesis {52314, title = {Soil-plant-livestock-weather relationships of a range ecosystem: Interactive timeshare regression and simulation model approaches}, year = {1973}, note = {//USDA//NONE//}, month = {1973}, pages = {94}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {

Data from Pasture Nine, Jornada Experimental Range, New Mexico, were used in regression and simulation modelling approaches to predicting perennial grass growth for use in management. These approaches served to illustrate the capabilities of timeshare computer facilities and APL (A Programming Language). Results of various regressions of the relationships of precipitation, days of soil moisture levels, and yield and cover of perennial grasses were used to heuristically develop a simulation model. Plotting the model output against the actual yields, although not statistically significant, gave promising results. The addition of parameters for evapo-transpiration could result in a valid model.

}, keywords = {dissertation, dissertations, grass productivity,model, grazing management,model, model,grass productivity, productivity,model, theses, thesis}, url = {files/bibliography/JWThesis2022.pdf}, author = {J. W. Russell} } @article {52319, title = {Soil temperatures at 10 and 50 cm for the Jornada site}, year = {1973}, note = {//??//US-IBP//}, month = {1973}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {book, books, chapter, chapters, report, reports, soil temperature}, isbn = {Research Memorandum 73-4}, author = {Walter G. Whitford and J. Ludwig and T. O{\textquoteright}Laughlin} } @article {52332, title = {Statistical analysis of intraseasonal herbage dynamics in a variety of grassland communities}, year = {1972}, note = {//??//US-IBP//}, month = {1972}, institution = {Colorado State University}, address = {Ft. Collins, Colorado}, keywords = {book, books, chapter, chapters, grassland community,herbage dynamics, report, reports}, isbn = {Technical Report 141}, author = {Francis, R. C. and M. Campion} } @article {52335, title = {Seed reserves in desert soils}, year = {1972}, note = {//??//US-IBP//}, month = {1972-74}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {book, books, chapter, chapters, report, reports, seed bank}, isbn = {Research Memorandum 72-8, 73-5, 74-16}, author = {D. W. Goodall and Childs, S. and Morgan, S.} } @article {JRN54834, title = {Some factors affecting response of anestrous ewes to hormone treatment}, journal = {Journal of Animal Science}, volume = {34}, year = {1972}, month = {June 1972}, pages = {1011-1019}, chapter = {1011}, abstract = {

Summary

Several experimental, range and farm flocks were used to study the effects of various environmental factors on response of the anestrous ewe to hormone therapy. Lactating ewes started on estrogen, progesterone and repeat PMS treatment beginning 18 to 24 days post-partum were significantly more fertile than ewes started on treatment 2 to 8 days post-partum. Ewes which lambed in June following the treatment described above were more fertile than ewes which lambed in February. However, both those lambing in June and February were more fertile than those lambing in April. Anestrous ewes suckling single lambs proved generally to be more fertile than ewes suckling twin lambs. In another study dry ewes (failed to lamb) were more fertile than ewes which lambed but did not raise their lambs. Ewes which lambed but failed to raise their lambs were in turn more fertile than ewes raising singles which in turn more fertile than ewes raising twins. A treatment including an intramuscular injection of 2 mg estradiol-17β at the time of progesterone implantation resulted in an apparent improvement in fertility in one flock and a significant improvement in fertility in another flock over other hormone treated ewes not receiving this estrogen pretreatment. Estradiol-17β (.025 mg) reduced fertility at the first estrus when it was given at the same time as the first PMS. The overall treatment effect did not, however, differ from other treatments. Young early post-partum ewes (1, 2 or 3 years old) whether lactating or nonlactating were significantly more fertile following hormone therapy than mature ewes of the same status. Dorset x Targhee crossbred ewes appeared to be more fertile following hormone therapy than Rambouillet, Targhee or Columbia ewes of the same ages. The response of Suffolk ewes to hormone treatment was significantly lower than other breeds studied in the same flock. Hormone treated lactating anestrous ewes given a high level of nutrition appeared to be more fertile than those on a standard level of nutrition.

}, keywords = {Anestrous Ewes, Factors Affecting Response, Hormone Treatment}, doi = {10.2527/jas1972.3461011x}, url = {https://dl.sciencesocieties.org/publications/jas/pdfs/34/6/JAN0340061011}, author = {Clarence V. Hulet and F. Stormshak} } @article {52342, title = {Small mammal studies on the Jornada and Pantex sites}, year = {1972}, note = {//NMSU ??//US-IBP//}, month = {1972}, pages = {48}, institution = {Colorado State University}, address = {Fort Collins, Colorado}, keywords = {book, books, chapter, chapters, report, reports, rodent, small mammal, SEE }, isbn = {Technical Report 114}, author = {Packard, R. L.} } @article {52347, title = {Survey of aquatic invertebrates at the Jornada site}, year = {1972}, note = {//USDA//US-IBP//}, month = {1972}, institution = {Colorado State University}, address = {Ft. Collins, Colorado}, keywords = {aquatic invertebrate,survey, book, books, chapter, chapters, invertebrate,aquatic,survey, report, reports}, isbn = {Research Memorandum 72-4}, author = {Ward, C. and Richardson, G. and E.W. Huddleston} } @mastersthesis {52348, title = {Some ecological relationships between creosotebush (Larrea tridentata DC.) and bush muhly (Muhlenbergia porteri Scribn)}, year = {1972}, note = {//NMSU//NONE//}, month = {1972}, school = {New Mexico State University}, type = {M.S. Thesis}, address = {Las Cruces, New Mexico}, abstract = {Bush muhly appears to dominate creosotebush and is perhaps responsible for the death of the creosotebush. A study in 1972 was conducted on New Mexico State University{\textquoteright}s Agricultural Experiment Station Ranch in Dona Ana County, New Mexico, to determine if the above statement is true, and if so, which factors may be responsible.}, keywords = {community, shrub-grass interaction, dissertation, dissertations, Larrea,grass interaction, Muhlenbergia,shrub interaction, productivity, Larrea, productivity,Muhlenbergia, theses, thesis}, author = {Welsh, Richard G.} } @proceedings {52360, title = {Small mammal studies and results in the grassland biome}, year = {1971}, note = {//USDA//US-IBP//NMSU library QH541.5 .P7 .P74//ProCite field[6]: In}, month = {September 1, 197}, pages = {213-240}, publisher = {Colorado State University}, address = {Colorado State University, Fort Collins, Colorado}, abstract = { Three types of information are conveyed: (i) an outline of the Grassland Biome small mammal studies, (ii) exemplary results from each of the subprojects, and (iii) summary analyses and observations drawn from the entire data bank. Significant differences in rodent catches are reported for different grazing treatments, soil types, and water stress treatments, but density estimates, home range, and areas-of-occupation charts reflect no such responses for jackrabbits on the intensive site in northeastern Colorado. Bimonthly dietary analyses of six small mammal species reflect a high degree of overlap between the herbivores, but strong niche segregation in general.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, grassland,function, grassland,lagomorphs, grassland,rodents, grassland,structure, Lagomorpha,grassland, proceeding, proceedings, Rodentia,grassland}, author = {Harris, L. D.}, editor = {Norman R. French} } @article {52366, title = {Soil associations and land classification for irrigation in Dona Ana County}, year = {1971}, note = {//LOCAL//NONE//}, month = {1971}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, chapter, chapters, irrigation,soil association, land classification, report, reports, soil association}, isbn = {Research Report 183}, author = {Maker, H. J. and Nehrer, R. H. and Derr, P. H. and J. U. Anderson} } @proceedings {52372, title = {Soils of the grassland biome sites}, year = {1971}, note = {//USDA//US-IBP//NMSU library QH541.5 .P7 .P74//ProCite field[6]: In}, month = {September 1, 197}, pages = {35-40}, publisher = {Colorado State University}, address = {Colorado State University, Fort Collins, Colorado}, abstract = { Although widely separated geographically and formed on diverse parent materials, nine of the ten dominant soils on the biome sites are classified in the Mollisol order. This order is comprised mainly of the dark, base rich soils of the semiarid and subhumid steppes. Even though they are consistent as to order, the soil properties vary widely. Texture varies from silty clay to loamy sand. Depth to bedrock varies from 35 to greater than 150 cm, and estimated available moisture storage capacity to 100 cm depth varies from 4.5 to 20 cm. While a few are acidic in the surface, with the exception of the mountain grassland, the soils tend to be largely base saturated. Native vegetation could be expected to respond to nitrogen fertilizer during periods when moisture availability is not limiting growth. Phosphorus responses might be expected at some sites. It is unlikely that native vegetation will respond to additions of other nutrients on these soils.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, grassland,soil properties, proceeding, proceedings, soil,grassland}, author = {Reuss, J. O.}, editor = {Norman R. French} } @proceedings {52384, title = {Some aspects of ecological climatology of the Jornada Experimental Range New Mexico}, year = {1970}, note = { //USDA//??//ProCite field[6]: In}, month = {June 19691970}, pages = {2-74}, publisher = {Colorado State University}, address = {University of New Mexico, Albuquerque}, abstract = { The following report is the joint effort of a small group working in the spring of 1969 in preparation for the workshop. Rainfall data did not arrive until late May, so the group concentrated on those features of the ecological climatolgy of the Jornada which it could consider with limited data. The report thus consists of three main parts: an analysis of the standard climatic factors that appear to limit the plants of the Jornada, an analysis of heat and moisture budgets appropriate to the cover types of the Jornada, and a preliminary estimate of the spatial and seasonal patterns of precipitation in equation form for use in a computer model. In addition to the workshop participants Hayden, Webb, Mitchell, and Bryson, the group was regularly joined by Dr. Katharina Lettau and Dr. F. Kenneth Hare whose contributions were very important.}, keywords = {abstract, abstracts, climate, heat and moisture budgets, climate, patterns, climate, phytogeographic, climate, precipitation, climate, temperature, conference, conference proceedings, conferences, model, vegetational analysis of climate, proceeding, proceedings}, author = {Bryson, Reid A. and Hayden, Bruce and Mitchell, Val and Webb, Thomas III}, editor = {R. G. Wright and G.M. Van Dyne} } @mastersthesis {52389, title = {Suitable habitat as a factor limiting pronghorn numbers on the Jornada Experimental Range}, year = {1970}, note = {//USDA, NMSU//NONE//}, month = {1970}, pages = {28}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Reports from historical records about the Jornada Experimental Range and the surrounding country indicate pronghorns were once abundant. Their presence number is quite low. The reason for the reduction of pronghorns can be correlated with the amount of preferred habitat present on the Jornada Plain. The present study showed pronghorns restricted their distribution to the grassland vegetational type present on the study area. The reason for the restriction was determined to be availability of food species. Literature was reviewed to determine the known plant species pronghorn utilized. A list was compiled and compared to a list of plant species that occur on the study area. Results showed that the majority of known pronghorn food species occurred in the grassland vegetational type. Feeding-time was recorded on pronghorns to determine the areas where they would spend time feeding. The results of these data showed they preferred the grassland vegetational type. Results from this study indicated that pronghorn numbers are low because of the small amount of suitable habitat present on the study area.}, keywords = {dissertation, dissertations, food habits, pronghorn antelope, grassland, pronghorn antelope, mammal, pronghorn antelope, pronghorn antelope, distribution, theses, thesis}, author = {Elmo Dwain Glidewell} } @conference {52392, title = {Seeding western rangelands}, booktitle = {Agronomy Abstracts}, year = {1970}, month = {1970}, pages = {78}, keywords = {seeding, western rangelands}, author = {C.H. Herbel} } @article {52402, title = {Soil water absorption capabilities in selected species of anurans}, journal = {Herpetologica}, volume = {26}, number = {4}, year = {1970}, note = {//NMSU//NONE//}, month = {1970}, pages = {411-418}, abstract = {

The relative ability of several species of anurans (Bufo americanus, B. cognatus, Hyla cinerea, Rana pipiens, Scaphiopus couchi, and S. hammondi) to absorb water from the soil was examined. Fossorial species from xeric habitats, S. couchi, S. hammondi and B. cognatus had absorption thresholds between 2.5 and 3 atm. In decreasing order of ability to absorb moisture from the soil were B. americanus, H. cinerea and R. pipiens. The ability of anurans to absorb moisture from the soil is probably a factor determining their distribution.

}, keywords = {amphibian, also SEE , anuran, soil water absorption, anuran,Bufo, anuran,Hyla, anuran,Rana, anuran,Scaphiopus, article, articles, Bufo, Hyla, journal, journals, Rana, Scaphiopus, toad, SEE }, url = {files/bibliography/70-Herpetologica-Whitford-2.pdf}, author = {Walker, Richard F. and Walter G. Whitford} } @proceedings {52406, title = {Simulation and Analysis of Dynamics of a Semi-Desert Grassland}, year = {1970}, note = {//USDA//NONE//}, month = {June 19691970}, publisher = {Colorado State University}, address = {University of New Mexico}, abstract = {A problem area in southern New Mexico was selected where data were available on long-term changes in the system, especially the vegetation, as a response to naturally occurring climatic fluctuations. The objective here was to try to extract from experience, the literature, and the data base enough information about the system to represent it in simulation models. Analysis of this total-system problem required crossing disciplines to secure personnel with adequate subject matter and analytical capabilities, operational approaches, and flexibility in attitude, outlook, and operation.}, keywords = {abstract, abstracts, cattle, vegetation interaction, cattle, wildlife relationships, conference, conference proceedings, conferences, drought, ecology, germination, grassland, dynamics, grazing, management, model, ecosystem, model, mathematical, plant, germination, plant, precipitation, precipitation, proceeding, proceedings, rodent, food habits, rodent, life history, rodent, population dynamics, rodent,habitat requirements, rodent,population dynamics, vegetation change}, author = {R. G. Wright and G.M. Van Dyne} } @proceedings {52415, title = {The Santa Fe group in the south-central New Mexico border region}, volume = {Circular 104}, year = {1969}, note = {//LOCAL//NONE//ProCite field[6]: In}, month = {1969}, pages = {52-57}, publisher = {New Mexico Bureau of Mines and Mineral Resources}, abstract = {The Santa Fe Group in the south-central New Mexico border region is a complex sequence of piedmont-slope alluvium; playa, lacustrine, and fluvial deposits; and some basaltic volcanic preserved in structural basins within and adjacent to the Rio Grande depression. The upper limit of the group is the surface of the youngest basin fill predating initiation of the Rio Grande Valley entrenchment. The lower limit is placed above volcanic and associated sedimentary rocks of Oligocene-early (?) Miocene age that are well exposed in the Caballo-Selden area. Studies of vertebrate and invertebrate faunas, determination of the potassium-argon age of interbedded basalt, and correlation of volcanic ash lenses have established a general Miocene to mid-Pleistocene age for the Santa Fe Group in the border region. Early stages of intermontane basin filling occurred in a closed-basin (classic bolson) environment, while later stages were marked by coalescence of basin floors and development of a regional system of through-drainage. Thus, Santa Fe group deposition in the border region corresponds with Bryan{\textquoteright}s idealized concept of basin filling in the type Santa Fe region to the north. Important economic resources in the Santa Fe Group include ground water, sand, gravel, clay, and caliche.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, geomorphology, piedmont-slope alluvium, geomorphology, Santa Fe Group, basaltic volcanics, geomorphology, Santa Fe Group, fluvial deposits, geomorphology, Santa Fe Group, lacustrine, geomorphology, Santa Fe Group, piedmont-slope alluvium, geomorphology, Santa Fe Group, playa, proceeding, proceedings}, author = {J. Hawley and Frank E. Kottlowski and W. R. Seager and King, William E. and Strain, William S. and LeMone, David V.} } @mastersthesis {52438, title = {Seeding, furrowing, brush removal, and rabbit exclusion effects on creosotebush-infested sites}, year = {1968}, note = {//USDA//NONE//}, month = {1968}, pages = {54}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {

Creosotebush (Larrea tridentata (DC) Cov.) dominates much of the formerly productive rangelands of the southwest. A successful and practical method of eradicating this shrub, followed by revegetation of the area by desirable forage plants, would greatly improve these creosotebush-infested areas for livestock use. The purpose of this factorially designed experiment was to study the effects of seeding, furrowing, brush removal, and rabbit exclusion on three creosotebush-infested sites on the Jornada Experimental Range, Las Cruces, New Mexico. Brush removal consistently decreased the canopy cover of creosotebush and total shrubs, regardless of other treatments. The brush removal alone or the brush removal x rabbit exclusion treatment significantly increased the grass species at the |Ragged and Parker Tank sites. The rabbit exclusion fence was present in the treatment applications that significantly increased the grass cover at the Dona Ana site. This treatment was significant in increasing the grass cover due to its soil retaining and soil depositional effects on this site with the steeper slope and the more severe erosion and runoff condition.

}, keywords = {brush removal, creosotebush, dissertation, dissertations, furrowing, Larrea, revegetation, rabbit exclusion, revegetation, seeding, theses, thesis}, url = {/files/bibliography/1968-1.pdf}, author = {Korzdorfer, Edward Jay} } @article {52456, title = {Seasonal suitability, a grazing system for ranges of diverse vegetation types and condition classes}, journal = {Journal of Range Management}, volume = {20}, year = {1967}, note = {//USDA//NONE//}, month = {1967}, pages = {395-397}, abstract = {Seasonal suitability grazing, a grazing system long in use on southwestern range, consists of grazing diverse vegetation types in accord with seasonal use requirements of and benefits to vegetation and livestock. On ranges of diverse vegetation types, it is a superior system with respect to maintenance and improvement of the range, harvest of forage and livestock production.}, keywords = {article, articles, grazing system, seasonal suitability, journal, journals, management, rangeland, seasonal suitability, rangeland, seasonal suitability}, author = {Valentine, K. A.} } @article {52457, title = {Some new and little known insects of economic importance on range grasses}, journal = {Journal of Economic Entomology}, volume = {60}, number = {4}, year = {1967}, note = {//LOCAL//NONE//}, month = {1967}, pages = {961-63}, abstract = {Several pests of range grass seed production, not previously reported, are described. About 60 species were observed. A new genus and species of Chloropidae caused major damage to developing seed of alkali sacaton, Sporobolus airoides Torr., and sand dropseed, S. cryptandrus (Torr.).....}, keywords = {article, articles, grass, insects, insect, range grasses, journal, journals, list, insects, range grasses}, author = {Watts, J. G. and Bellotti, A. C.} } @article {52469, title = {Species preference of Hereford and Santa Gertrudis cattle on a southern New Mexico range}, journal = {Journal of Range Management}, volume = {19}, number = {4}, year = {1966}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {July 1, 1966}, pages = {177-181}, abstract = {The species preferences of Hereford and Santa Gertrudis cows were observed during a 3-year period. The cattle grazed a variety of species, undoubtedly an important factor affecting nutritional status. They ate, to some extent, all available species. There was no apparent difference between breeds in the quantity of coarse plants consumed. The species grazed by livestock and the species preferred during various seasons are important in formulating grazing management plans and for nutritional studies. Season of growth, succulence, abundance, and nutritive qualities are plant properties influencing species preference. Tribe (1952) reported that in animals, age, stage of pregnancy, general physical condition, and hunger also affect grazing preference. The purpose of this portion of the overall study was to determine the plants grazed by cattle during the various seasons.}, keywords = {cattle, hereford, range, Santa Gertrudis, southern New Mexico, species preference}, url = {/files/bibliography/099.pdf}, author = {C.H. Herbel and Nelson, A.B.} } @mastersthesis {52498, title = {A survey of fleshy fungi in south central New Mexico}, year = {1963}, note = {//LOCAL//NONE//}, month = {1963}, school = {New Mexico State University}, type = {M.S. Thesis}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, fungi,key, key,fungi, theses, thesis}, author = {Chavez, Henry B.} } @article {52521, title = {Shrub invasion of a southern New Mexico desert grassland range}, journal = {Journal of Range Management}, volume = {11}, year = {1958}, note = {//USDA//NONE//}, month = {1958}, pages = {129-132}, abstract = { The grazing value of a large portion of the desert grassland in southwestern United States has been greatly reduced during the last 100 to 150 years by the invasion of undesirable shrubs. Although much of the present area is now lightly infested, infestation does not have to be heavy before range productivity is seriously damaged. As the economic welfare of the Southwest depends in large measure upon its grazing and soil resources, investigations to determine the extent of shrub invasion, rate of range deterioration, and possible reasons for this retrogression in plant cover are important. In this study, records of vegetational changes, environmental conditions, and forage utilization were compiled and analyzed in an attempt to determine the extent of shrub invasion on a southern New Mexico semidesert grassland range over a thirty-year period.}, keywords = {article, articles, brush control, Flourensia, brush control, Gutierrezia, brush control, Larrea, brush control, Prosopis, community, grassland, community, shrub, Flourensia encroachment, grassland, shrub encroachment, Gutierrezia encroachment, journal, journals, Larrea encroachment, Prosopis encroachment, shrub encroachment}, author = {Branscomb, Bruce L.} } @article {52524, title = {Supplements for range cows}, year = {1958}, note = {//??//NONE//}, month = {1958}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, cattle,supplement, chapter, chapters, nutrient,cattle supplements, report, reports}, isbn = {Bulletin 425}, author = {Knox, J. H. and Watkins, W. E.} } @article {52534, title = {Size and composition of the herd}, journal = {American Cattle Producer}, volume = {34}, number = {7}, year = {1952}, month = {December 1952}, pages = {14, 16, 18}, abstract = {The size and makeup of the herd is important in obtaining sustained cattle production and maximum returns from Southwestern ranges. In this region of severe and recurrent drought, forage supplies are uncertain and the cattleman must be ever ready to adjust his herd and his operations as the weather dictates. On most ranches, breeding cowsform the backbone of the herd. The principal market products are calves sold in the fall and yearlings sold in the spring. These range-raised growing animals are in good demand as stockers and feeders. Breeding cows are difficult to move and demand for them is likely to be poor, especially during drought. Furthermore, when the stockman is forced to reduce his breeding herd because of inadequate forage he sacrifices the results of years of effort in selection and grade improvement. Most of the forage on semidesert ranges consists of grasses which make their growth during the summer rainy season. Much of the herbage produced cures well on the stalk and provided year-long grazing. Accordingly, the stockman is able to judge the amount of hisforage supply in the fall and can plan hisyear{\textquoteright}s operation. Grazing tests at the Jornada Experimental Range provide information on the kind of herd composition and date of stocking which will produce high calf crops, low death losses and consistently good beef production and yearly income.}, keywords = {cattle production, grazing tests, herd composition, herd size}, url = {/files/bibliography/075.pdf}, author = {F.N. Ares} } @article {52556, title = {Seasonal feeding of mineral supplements}, year = {1946}, note = {//??//NONE//}, month = {1946}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, cattle,supplements, chapter, chapters, nutrient,cattle supplements, report, reports}, isbn = {Bulletin 331}, author = {Knox, J. H. and Benner, J. W. and Watkins, W. E.} } @article {52562, title = {A short-cut method for checking degree of forage utilization}, journal = {Journal of Forestry}, volume = {42}, year = {1944}, month = {1944}, pages = {294-295}, abstract = {A shortcut in estimating the degree of forage utilization recommended to the range examiner whose time or technical knowledge and skill in range work are limited has been developed and tested at the Southwestern Forest and Range Experiment Station. Its basis is the fact that the percentage of close grazing is proportional to the percentage of total use. As determined by statistical analysis of grazed, stubble-height measurements obtained in repeated range surveys, there exists a high degree of correlation between the percentages of grasses grazed at a stubble height of 2 inches or less, the percentages of partly grazed, and the percentages of ungrazed forage. When the percentage of 2-inch grazing is known, the associated percentage of partly grazed and the percentage of ungrazed forage may be read directly from a set of stubble-height distribution curves presented in chart form.}, keywords = {estimating, forage utilization, stubble-height measurements}, url = {/files/bibliography/067.pdf}, author = {Canfield, R.H.} } @article {52580, title = {Seasonal calcium and phosphorous requirements of range cattle as shown by blood analysis}, year = {1941}, note = {//??//NONE//}, month = {1941}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, calcium,cattle, cattle,nutrition, chapter, chapters, nutrition,cattle, phosphorous,cattle, report, reports}, isbn = {Bulletin 282}, author = {Knox, J. H. and Benner, J. W. and Watkins, W. E.} } @article {52590, title = {Semideferred grazing as a restorative measure for black grama ranges}, number = {Research Note 80}, year = {1939}, month = {1939 (Revised 19}, pages = {4 }, institution = {USDA, Forest Service, Southwest Forest and Range Experimental Range Station}, abstract = {The Southwestern Forest and Range Experiment Station is engaged in a series of long-time experiments designed to determine the best method of handling each of the important types of range occurring in southern Arizona, New Mexico, and west Texas. Among the native forage plants in this area, probably the one of highest economic value is black grama (Bouteloua eriopoda). As such, it is deserving of particular attention from the standpoint of range management. The purpose of this note is to describe one of the methods that have proven successful by experimentation in the restoration of depleted black grama ranges on the Jornada Experimental Range in southern New Mexico. The pasture in which this experiment was conducted is representative of the black grama type that is commonly spotted with tobosa grass (Hilaria matica) flats on the heavier soils. The black grama areas are not pure stands but contain, in addition to black grama, a mixture of summer palatable grasses. These are principally sand dropseed (Sporobolus spp.) and three-awn grasses (Aristida spp.).}, keywords = {black grama, Bouteloua eriopoda, research notes, restoration method, semideferred grazing}, url = {/files/bibliography/050.pdf}, author = {Canfield, R.H.} } @article {52600, title = {A study of poisonous drymaria on southern New Mexico ranges}, journal = {Ecology}, volume = {18}, year = {1937}, month = {1937}, pages = {416-426}, abstract = {Among the harmful plants that grow on clay (adobe) soils on ranges of southern New Mexico, the most poisonous for cattle are dwarf summer annuals of the species Drymaria holostcoides Bentham (D. pachyphylla \Woot. and Standl.). Of more than a dozen species of J)rvmaria occurring in Central America, Mexico and southwestern United States, members of only the species named are known to be toxic. These plants have been found in southern New Mexico, southwestern Texas, southeastern Arizona, and Mexico. Because of the great number of deaths of range cattle caused by eating these poisonous plants, a study of them was made by the author in 1934 and 1935 with a view to determining feasible methods of eradication and how livestock losses might be reduced. These investigations were made at the Jornada Experimental Range, U.S. Forest Service, near Las Cruces, New Mexico. Discovery of these plants as poisonous is recent. In 1922, the New Mexico Agricultural Experiment Station and the Bureau of Plant Industry, U.S. Department of Agriculture, began a cooperative study of these plants. Lantow ({\textquoteright}29), of the former institution, demonstrated their extreme toxicity to cattle and sheep in feeding experiments from 1923 to 1927 and found all parts of the plants above ground to be poisonous at all stages of growth. Because of the unpalatability of the plants, forced feeding was necessary. Campbell ({\textquoteright}31) showed poisonous drymaria to be a pioneer weed in plant succession on clay soils, and made germination tests of the seeds. Mathews ({\textquoteright}33) conducted additional feeding experiments in southwestern Texas in 1932 and determined lethal doses. He reported that the plants caused death in a cow when they were eaten at the low rate of 0.4 percent of body weight, in a sheep at 0.6 pe cent, and in a goat at 0.97 percent. The toxic principle has not been determined.}, keywords = {cattle, harmful plants, poisonous drymaria, southern New Mexico}, url = {/files/bibliography/036.pdf}, author = {E. L. Little Jr.} } @article {52610, title = {Stem structure of grasses on the Jornada Experimental Range}, journal = {Botanical Gazette}, volume = {95}, year = {1934}, month = {1934}, pages = {636-648}, abstract = {

The orthodox description of the grass family contains the phrase "stems usually hollow" which has been generally accepted as meaning that all mature grasses other than the genera of the Andropogoneae and Nazieae have hollow stems. Early in 1927, when certain grasses not members of either of these tribes were examined, they were found to have solid stems. Continued investigation showed that a very high percentage of the mature grasses native to the semiarid Jornada plain have solid internodes. Bews states that the stems of grasses are usually hollow, but a number of "types" have solid stems, including the Andropogoneae and many of the Paniceae. Vavilov (6) also refers to a solid-stemmed variety of Agropyrum crislatum Beauv., which he reports as being widely distributed over European and Asiatic Russia.

}, keywords = {grasses, Jornada Experimental Range, stem structure}, url = {/files/bibliography/026.pdf}, author = {Canfield, R.H.} } @article {52614, title = {Solid and hollow stemmed grasses of the Jornada Experimental Range}, volume = {78(2024)}, year = {1933}, month = {1933}, pages = {342}, abstract = {

Orthodox descriptions of the grass family contain the statement "stems usually (or mostly) hollow." This characterization has been generally accepted as applying to all mature grasses other than the genera grouped under the tribes Andropogoneae and Nazieae, which are usually cited as exceptions. My own conception of the stem structure of grasses conformed to this description until early in 1927 when certain grasses, not members of either of the excepted tribes, were found to have solid stems. This discovery led to further investigations, the results of which show that a very high percentage of the mature grasses native to the Jornada plains in southern New Mexico have solid internodes.

}, keywords = {hollow-stemmed grasses, internodes, occurrence, solid-stemmed grasses}, url = {/files/bibliography/023.pdf}, author = {Canfield, R.H.} } @article {52620, title = {Supplemental feeding of range cattle}, year = {1930}, note = {//??//NONE//}, month = {1930}, institution = {New Mexico Agricultural Experiment Station}, keywords = {book, books, cattle,supplemental feeding, chapter, chapters, report, reports}, isbn = {Bulletin 185}, author = {Lantow, J. L.} } @article {52624, title = {Soapweed}, year = {1929}, month = {June 18, 1929}, pages = {1}, abstract = {

Soapweed (Yucca elata) is a perennial evergreen belonging to the lily family. The stems vary from 3-6 feet in height, although some specimens as tall as 30 feet have been observed. The slender, sharp-pointed leaves forming the green crown vary from 1-2 feet in length, and although they die after the second or third year, they are persistent on the stem. The soapweed annually produces a lateral expansion of the stem, an unusual phenomenon for a member of the lily group. Yucca is found through southern Arizona and New Mexico to western Texas and into old Mexico. It commonly occurs on sandy soils of grama grass range. The number of plants may vary from a few up to about 300 per acre. Stockmen regard the soapweed as a valuable forage plant since cattle may often graze almost entirely upon the green leaves during the spring months when grass is short. The tender flower stalks and flowers are eaten with considerable relish by cattle; from 1916 to 1919, the succulent stems and leaves were chopped for ensilage and used extensively in southern New Mexico for supplemental feeding. The plant is a desirable ornamental shrub but is rather difficult to transplant. The soapweed stem and leaves contain abundant fibers of potential economic value. The fibrous strands laid down by the growing point of the stem are much branched and are continuous with those of the eaves. The older stem makes a small, annual addition of straight fiber lateral to those produced by the growing point.

}, keywords = {description, government publication, perennial evergreen, soapweed, Yucca elata}, url = {/files/bibliography/016.pdf}, author = {R.S. Campbell} } @mastersthesis {JRN54580, title = {Seed Germination in Certain New Mexico Range Grasses}, year = {1928}, month = {04/1928}, pages = {25}, school = {University of Chicago}, abstract = {

Much work has been carried on in recent years in regard to the viability and germination of seeds of various plants. Seed-testing studies are highly important, because the results obtained influence or affect the work of the farmer, the floriculturist, the amateur gardener, and the rancher or ranger. These people cannot afford to plant seeds, expecting a 95 per cent germination and then perhaps having only a 50 per cent germination, due to poor selection of seed, to its immaturity, or to its adulteration with weed seeds. Among the plants studied for germination the grasses have a
prominent part, and this is especially true of the range grasses of the west. It is necessary for the rancher or ranger to know about what percentage of the seeds of the grasses covering his grazing lands he can expect to germinate, since he can then estimate the amount of grazing his lands will tolerate without becoming depleted. He must know whether his grasses propagate themselves vegetatively or by seed, or by both means. Various studies have been made with reference to seed germination, and although they have no direct bearing upon the problem which the writer\  undertook, yet they gave ideas for some tests which were performed after the major problem was completed. The following are short summaries of the work of some of the investigators in the field of seed germination.

}, keywords = {botanical gazette, Jornada Range Reserve Station, Seed germination}, doi = {10.1086/333900}, url = {files/bibliography/1928-1.pdf}, author = {Jackson, Carola V.} } @article {52633, title = {Saving livestock from starvation on Southwestern ranges}, year = {1924}, month = {1924}, pages = {22 }, publisher = {U.S. Department of Agriculture, Farmers{\textquoteright} Bulletin 1428}, keywords = {government publication, livestock, Southwestern ranges, starvation}, author = {Forsling, C.L.} } @article {52654, title = {Structure of the Jornada del Muerto}, journal = {Trans St. Louis Acad. Sci.}, volume = {1}, year = {1858}, note = {//??//NONE//}, month = {1858}, pages = {341}, keywords = {article, articles, history, Jornada del Muerto, journal, journals}, author = {Shumard, G. G.} }