@article {JRN55379, title = {An inductive approach to developing ecological site concepts with existing monitoring data}, journal = {Rangeland Ecology \& Management}, volume = {83}, year = {2022}, month = {7/2022}, pages = {133-148}, abstract = {Ecological sites comprise a land classification system that represents potential vegetation states and their management needs for different soils and climates. In the Rio Grande del Norte National Monument (RGdNNM) in northern New Mexico, uncertainty about the patterns and drivers of vegetation states impedes sustainable land management. Similar challenges are ubiquitous across terrestrial ecosystems and in particular landscapes with high spatial variability in soils and climate. Lack of suitable data has been a barrier to large-scale ecological site development based on quantitative observations. We used data from existing federal monitoring programs alongside spatial, environmental, and land use data to test for the role of climate, geomorphology, soils, and land use history on vegetation communities in RGdNNM. The monitoring dataset was collected with standardized monitoring methods implemented by the Bureau of Land Management{\textquoteright}s Assessment, Inventory, and Monitoring program and the Natural Resources Conservation Service{\textquoteright}s Landscape Monitoring Framework program. Eleven ecological site concepts and paired vegetation communities were identified using multivariate fuzzy clustering and classification tree analysis to determine the influence of abiotic variables on vegetation communities. The ecological site and vegetation community concepts developed for RGdNNM demonstrate how existing monitoring data can be used to interpret the structural and functional characteristics of landscapes. A workflow for applying monitoring data to landscape classification is presented to support the broader framework for ecological site development.}, keywords = {climates, ecological site concepts, inductive approach, management, monitoring data, soils, vegetation states}, doi = {https://doi.org/10.1016/j.rama.2022.03.009}, url = {files/bibliography/22-010.pdf}, author = {A. Heller and Nicholas Webb and Brandon T Bestelmeyer and Colby Brungard and Zoe Davidson} } @proceedings {JRN55432, title = {The impact of vegetation removal by oil and gas development on wind erosion and dust emission in the Upper Colorado River Basin}, year = {2022}, abstract = {Wind erosion and dust emission from drylands have large consequences for ecosystem function and human life in the western United States. In drylands of the Upper Colorado River Basin (UCRB), human land uses have reduced vegetation (i.e., surface roughness) with potential to dramatically increase wind erosion and dust emission, which impact soils by selectively removing fine sediment containing carbon and nutrients and negatively affect air quality with implications for human health and wellbeing. Subsequent dust deposition on mountain snowpack changes surface albedo and alters regional hydrology. Extraction of oil and natural gas is a common and growing land use in the UCRB that removes vegetation and disturbs soils through installation of well pads and roads. Over the past century, this disturbance has produced over 100,000 small (~ 1 ha), discrete patches of unprotected soil in the UCRB. In this study, we used 16 years of Moderate Resolution Imaging Spectroradiometer (MODIS) albedo (MCD43A3; daily 500 m) to assess the effect of oil and gas development on surface roughness in the Uinta-Piceance Basin, a heavily developed area of the UCRB, and modeled how the change in surface roughness could impact aeolian sediment flux. We found that oil and gas activity reduced surface roughness and increased aeolian sediment fluxes by 12\% to 18,400\% across much of the study region. However, in areas that were heavily invaded by annual forbs and grasses, sites disturbed by oil and gas had larger surface roughness and smaller total aeolian sediment fluxes than undisturbed sites. The net increase in modeled dust emission from the Uinta-Piceance Basin due to oil and gas activity was small (0.33 gm-1s-1 for a 12 ms-1 wind speed when threshold friction velocity was 0.20 ms-1). However, even a very small dust concentration on snowpack (<10 mgg-1 of snow) can accelerate snowmelt and runoff. Our model results suggest that oil and gas activity intensifies the potential for wind erosion and dust emission from landscapes in the UCRB. Furthermore, this work reveals an opportunity to identify mechanisms that mitigate land use-driven dust emission and subsequent ecohydrological impacts in this region.}, author = {Gayle Tyree and A. Chappell and Miguel L Villarreal and Saroj Dhital and Danielle Duni and Brandon Edwards and Akasha M. Faist and Travis Nauman and Nicholas Webb} } @article {JRN55302, title = {Improving Landsat predictions of rangeland fractional cover with multitask learning and uncertainty}, journal = {Methods in Ecology and Evolution}, volume = {12}, year = {2021}, month = {1/28/2021}, pages = {841-846}, abstract = {1.Operational satellite remote sensing products are transforming rangeland management and science. Advancements in computation, data storage and processing have removed barriers that previously blocked or hindered the development and use of remote sensing products. When combined with local data and knowledge, remote sensing products can inform decision-making at multiple scales. 2. We used temporal convolutional networks to produce a fractional cover product that spans western United States rangelands. We trained the model with 52,012 on-the-ground vegetation plots to simultaneously predict fractional cover for annual forbs and grasses, perennial forbs and grasses, shrubs, trees, litter and bare ground. To assist interpretation and to provide a measure of prediction confidence, we also produced spatiotemporal-explicit, pixel-level estimates of uncertainty. We evaluated the model with 5,780 on-the-ground vegetation plots removed from the training data. 3. Model evaluation averaged 6.3\% mean absolute error and 9.6\% root mean squared error. Evaluation with additional datasets that were not part of the training dataset, and that varied in geographic range, method of collection, scope and size, revealed similar metrics. Model performance increased across all functional groups compared to the previously produced fractional product. 4. The advancements achieved with the new rangeland fractional cover product expand the management toolbox with improved predictions of fractional cover and pixel-level uncertainty. The new product is available on the Rangeland Analysis Platform (https://rangelands.app/), an interactive web application that tracks rangeland vegetation through time. This product is intended to be used alongside local on-the-ground data, expert knowledge, land use history, scientific literature and other sources of information when making interpretations. When being used to inform decision-making, remotely sensed products should be evaluated and utilized according to the context of the decision and not be used in isolation. }, keywords = {conservation, convolutional neural network, grassland, machine learning, monitoring, rangeland management, remote sensing, temporal convolutional network}, doi = {10.1111/2041-210X.13564}, url = {files/bibliography/21-028.pdf}, author = {Brady W. Allred and Brandon T Bestelmeyer and Chad S. Boyd and Christopher Brown and K. W. Davies and Danielle Duni and Lisa M. Ellsworth and Tyler A. Erickson and S. Fuhlendorf and Timothy V. Griffiths and Vincent Jansen and Matthew O. Jones and Jason W. Karl and A. D. Knight and J. Maestas and Jonathan Maynard and Sarah McCord and David E. Naugle and Heath D. Starns and Dirac Twidwell and Daniel R. Uden} } @article {JRN55412, title = {Integrating human dimensions within the LTAR Network to achieve agroecological system transformation}, journal = {Rangelands}, year = {2021}, month = {7/3/2021}, abstract = {On the Ground {\textbullet} Agroecosystem research often focuses on biophysical processes and productivity without incorporating human dimensions research and/or stakeholder engagement. {\textbullet} Connecting individual and community well-being to agro-innovation research is required for agro-ecological transformation to sustainable intensification. {\textbullet} Long-Term Agroecosystem Research (LTAR) Network sites have historically had varied degrees of human dimensions research within their research plan; however, LTAR{\textquoteright}s human dimensions capacity has grown. {\textbullet} To capitalize on this capacity, we propose a four-step framework for the LTAR Network to evolve a cohesive human dimensions strategy that brings together the social and ecological. {\textbullet} Continued institutional support is required to maintain and further pursue research that will support stakeholder co-developed science that facilitates agroecosystem transformations benefiting society.}, keywords = {agroecosystems, human dimensions, stakeholder engagement, Sustainable intensification, well-being}, doi = {10.1016/j.rala.2021.05.002}, url = {files/bibliography/21-064.pdf}, author = {Gwendwr Meredith and A. R. Bean and Amanda Bentley Brymer and Claire Friedrichsen and Zachary Hurst} } @conference {JRN55422, title = { Invasive plant species effects on wind and water erosion across US grazing lands }, booktitle = {LTAR Annual Meeting}, year = {2021}, month = {7/16/2021}, abstract = {Soil erosion by wind and water reduces the productive potential of agroecosystems, threatening the efficacy of climate change mitigation and adaption, and strategies for the sustainable intensification of agriculture. The extensive US grazing lands encompass diverse ecosystems with different inherent resistance and resilience to erosion. Land uses, land management, and disturbances vary across these regions and have great potential to change (accelerate or reduce) soil erosion rates. Over the last century, a combination of land management pressures (e.g., grazing), altered fire regimes, drought, and climate change have facilitated establishment and spread of invasive plant species across grazing lands, which has directly and indirectly affected the susceptibility of sites to soil erosion. The LTAR Rangeland Soil Erosion Working Group is collaborating with natural resource agencies (NRCS and BLM) to understand how invasive plant species are influencing wind and water erosion across public and private grazing lands, and where conservation practices may be most effective. We are applying the Aeolian Erosion (AERO) model and Rangeland Hydrology and Erosion Model (RHEM) to estimate aeolian sediment transport and water erosion rates using monitoring datasets collected by the NRCS and BLM at over 60,000 locations and harmonized in the Landscape Data Commons. The erosion indicators are being assessed relative to indicators of vegetation cover and structure, including invasive and native species, which attenuate soil erosion. We hypothesize that vegetation cover and structure are influenced by the presence and cover of invasive plant species, and that modelled indicators of soil erosion are responding across ecoregions.}, keywords = {erosion, Invasive plant, species, US grazing lands, water, wind}, author = {Nicholas Webb and Sarah McCord and Kristopher Bonefont and Ericha Courtright and Danielle Duni and Brandon Edwards and David C. Goodrich and Phil Heilman and Mariano Hernandez and Lori Metz and Daniel N. Moriasi and Mark A. Nearing and Beth Newingham and Nichols, Mary H. and Frederick B. Pierson and John Tatarko and David P. Toledo and Scott Van Pelt and Justin Van Zee and Jason Williams} } @book {JRN55232, title = {Interpreting indicators of rangeland health, version 5}, series = {Interpreting Indicators of Rangeland Health, Version 5}, year = {2020}, pages = {202}, publisher = {BLM National Operations Center{\textquoteright}s Information and Publishing Services Section }, organization = {BLM National Operations Center{\textquoteright}s Information and Publishing Services Section }, address = {Denver}, abstract = {Rangeland Health refers to the degree to which the integrity of the soil, vegetation, water, and air as well as the ecological processes of rangeland ecosystems are balanced and sustained. The most commonly used rangeland health assessment protocol on US rangelands is the Interpreting Indicators of Rangeland Health (IIRH) assessment. Interpreting Indicators of Rangeland Health was initiated in 1994 as a qualitative, rapid assessment technique to evaluate rangeland health. Seventeen field indicators are used to rate three attributes of rangeland health: 1) soil/site stability, 2) hydrologic function, and 3) biotic integrity. The published versions of this protocol are version 3 (2000) and version 4 (2005). Version 5 represents a continuing effort by an interagency cadre to improve the use of and consistency of results when using this protocol. The revision improves the development or modification of reference sheets and clarifies that the reference for conducting evaluations is the natural range of variability within the natural disturbance regime of the reference state. More emphasis is also placed on the functional/structural worksheet in conducting evaluations. This revision also supports linking qualitative and quantitative measurements, where quantitative measurements may also be used for baseline monitoring.}, url = {files/bibliography/20-029.pdf}, author = {M. Pellant and P. L. Shaver and D.A. Pyke and Jeffrey E. Herrick and F. Busby and Riegel, Gregg and Nika Lepak and Emily Kachergis and Beth Newingham and David P. Toledo} } @article {JRN55156, title = {Indicators and benchmarks for wind erosion monitoring, assessment and management}, journal = {Ecological Indicators}, volume = {110}, year = {2020}, month = {01/10/2020}, abstract = {

Wind erosion and blowing dust threaten food security, human health and ecosystem services across global drylands. Monitoring wind erosion is needed to inform management, with explicit monitoring objectives being critical for interpreting and translating monitoring information into management actions. Monitoring objectives should establish\ quantitative guidelines for determining the relationship of wind erosion indicators to management benchmarks that reflect tolerable erosion and dust production levels considering impacts to, for example, ecosystem processes, species, agricultural production systems and human well-being. Here we: 1) critically review indicators of wind erosion and blowing dust that are currently available to practitioners; and 2) describe approaches for establishing benchmarks to support wind erosion assessments and management. We find that while numerous indicators are available for monitoring wind erosion, only a subset have been used routinely and most monitoring efforts have focused on air quality impacts of dust. Indicators need to be related to the causal soil and vegetation controls in eroding areas to directly inform management. There is great potential to use regional standardized soil and vegetation monitoring datasets, remote sensing and models to provide new information on wind erosion across landscapes. We identify best practices for establishing benchmarks for these indicators based on experimental studies, mechanistic and empirical models, and distributions of indicator values obtained from monitoring data at historic or existing reference sites. The approaches to establishing benchmarks described here have enduring utility as monitoring technologies change and enable managers to evaluate co-benefits and potential trade-offs among ecosystem services as affected by wind erosion management.

}, keywords = {adaptive management, aeolian, Air quality, dust, ecological thresholds, Reference site}, doi = {10.1016/j.ecolind.2019.105881}, url = {files/bibliography/20-001.pdf}, author = {Nicholas Webb and Emily Kachergis and Scott W. Miller and Sarah McCord and Brandon T Bestelmeyer and Joel R. Brown and A. Chappell and Brandon Edwards and Jeffrey E. Herrick and Jason W. Karl and John Leys and Loretta Metz and Steve Smarik and John Tatarko and Justin Van Zee and G. Zwicke} } @conference {JRN55063, title = {Islands of resilience: Community challenges and responses to the 2018 Colorado Plateau exceptional drought}, booktitle = {Universities Council on Water Resources}, year = {2019}, month = {06/2019}, address = {Snowbird, UT}, abstract = {

Exceptional drought persisted over the Colorado Plateau and adjacent regions for nearly all 2018. This area serves as the headwaters for major rivers including tributaries to the Colorado River and the Rio Grande. Historic agriculture, extensive public lands, and recreation and tourism were impacted by unprecedented drought. We explore factors conferring community resilience in the context of drought typology and impact time-frame. Drought typology includes 1) meteorological drought (precipitation deficit), 2) agricultural drought (soil moisture deficit), 3) hydrological drought (deficit in water resources), and 4) socioeconomic drought (when the former definitions impact the supply and demand of goods). Impact time-frame includes short-term impacts lasting weeks to months and long-term impacts potentially lasting a year or more. Specific short-term impacts observed in 2018 include dry stock tanks, limited forage quantity and quality and the immediate response to the 416 fire, which burned 55,000 acres in the San Juan National Forest over 61 days. Longer-term impacts of the 2018 drought include local and regional diminished water supply, poor water quality, fish kills, post-fire mudslides in the burn scar and producer decisions to permanently transition out of agriculture. Community drought resilience efforts began in January, when dismal snowpack led to community leader meetings followed by drought informational meetings with irrigators. Water-specific factors conferring resilience include plentiful initial reservoir water storage, sophisticated irrigation system planning, owning senior water rights or having access to groundwater, and establishment of shortage sharing agreements (e.g. Animas River irrigators). As drought conditions continued, producers hauled water for livestock and wildlife. Others had to fallow lower-value crops and hand-water high-value crops. Local service-based organizations (Good Food Collective and Spring Creek Horse Rescue) and established supportive relationships between land-owner and rancher led to resilience in specific instances. Geographically decoupled water sources from demands led to longer-term, distant impacts of exceptional drought in this headwaters region. Throughout the drought webinars featuring weather and climate experts provided updates which were used by local managers and the media to communicate drought progress and resources.

}, author = {Emile H. Elias and Caitriana Steele and J.T. Reyes and David A. Brown and Behery, Susan and Weight, Elizabeth} } @article {JRN54890, title = {Integrating space and time: A case for phenological context in grazing studies and management}, journal = {Frontiers of Agricultural Science and Engineering}, volume = {5}, year = {2018}, month = {03/2018}, pages = {44-56}, chapter = {44}, abstract = {

In water-limited landscapes, patterns in primary production are highly variable across space and time. Livestock grazing is a common agricultural practice worldwide and a concern is localized overuse of specific pasture resources that can exacerbate grass losses and soil erosion. On a research ranch in New Mexico (MAP = 217 mm), we demonstrate with a quantitative approach that annual seasons vary greatly and examine foraging patterns in Angus-Hereford (Bos taurus) cows. We define five seasonal stages based on MODIS NDVI: Pre-Greenup, Greenup, Peak Green, Drydown, and Dormant and examine livestock movements in 2008. Daily distance traveled by cows was greater and foraging area expanded during periods with higher precipitation. A regression model including minimum NDVI, rainfall, and NDVI*rainfall explained 81\% of the seasonal variation in distance traveled by cows (P \< 0.01). Cows explored a daily average 81.1 ha while foraging but tended to explore smaller areas as the pasture became greener (Greenup, Peak Green). Cows foraged an average 9.7 hours daily and spent more time foraging as pastures became greener. Our findings suggest that phenological context can expand the capacity to compare and integrate findings and facilitate meta-analyses of grazing studies conducted at different locations and times of year.

}, keywords = {GPS collars, Jornada Experimental Range, land-surface phnology, livestock movement, LTAR, MODIS NDVI, rangeland}, doi = {10.15302/j-FASE-2017193}, url = {files/bibliography/18-006.pdf}, author = {Dawn M. Browning and S. Spiegal and Richard E. Estell and Andr{\'e}s F. Cibils and H. Raul Peinetti} } @conference {JRN54908, title = {Invasive Plant Expansion on Spatially Heterogeneous Landscapes: Hot Spots and Hot Moments}, booktitle = {Ecological Society of America}, year = {2018}, month = {08/2018}, publisher = {Ecological Society of America}, organization = {Ecological Society of America}, address = {New Orleans, LA}, abstract = {

Lehmann lovegrass (Eragrostis lehmanniana) is an invasive non-native perennial grass introduced at multiple locations in the American Southwest in the 1930s to restore ground cover and forage production on overgrazed, eroded rangelands. Since that time it has aggressively expanded throughout the Sonoran Desert where now dominates many landscapes. The Chihuahuan Desert, in contrast, has been resistant to its expansion, with local E. lehmanniana patches being dynamic without a clear trend. Climate and soils are known to influence broad-scale distributions of E. lehmanniana. We hypothesize that at the landscape-scale, expansion will be affected by seed availability. Accordingly, we sought to identify the {\textquotedblleft}hot spots{\textquotedblright} and {\textquotedblleft}hot moments{\textquotedblright} of spread across a landscape with spatially heterogeneous soils, climate, and current patch locations that affect seed availability. Long-term climate and spatially-resolved soils data were used to parameterize and test a numerical ecosystems model at the Jornada LTER-USDA site in the northern Chihuahuan Desert. We simulated E. lehmanniana recruitment and spread either assuming (i) seeds were always available or (ii) seed availability was a function of the distance from an existing patch. When seed availability was not constrained, E. lehmanniana recruitment was largely confined to years with above-average annual temperature and variable precipitation. Soils with higher silt content intensified the climate effects on recruitment. When seed availability was constrained, distance from existing patches was the primary driver of E. lehmanniana expansion and it interacted with climatic and edaphic parameters and generate non-linear rates and patterns of spread. Areas downwind from established patches and areas near large patches had the highest E. lehmanniana establishment probabilities. This approach can be used to strategically (i) identify hot spots and hot moments of potential E. lehmanniana expansion into native Chihuahuan Desert ecosystems under dynamic and changing climatic conditions and (ii) prioritize the location of monitoring sites and the timing of their sampling.

}, author = {N. Dylan Burruss and Debra C. Peters and Steven R. Archer} } @article {JRN54888, title = {Improving ground cover monitoring for wind erosion assessment using MODIS BRDF parameters}, journal = {Remote Sensing of Environment}, volume = {204:756-768.}, year = {2018}, month = {09/29/2017}, abstract = {

Measuring and monitoring controls on wind erosion can facilitate detection and prediction of soil degradation important for food security. Ground cover is widely recognised as an important factor for controlling soil erosion by wind and water. Consequently, maintaining ground cover (e.g., vegetation, crop canopy, crop residue) is a recommended management practice which is widely adopted by farmers and land owners. Wind erosion is a lateral or horizontal process and the amount of ground cover needed to maintain lateral cover (Lc =nbh/S where n roughness elements occupy ground area S and have b and h mean breadth and height, respectively) is not wellestablished. Soil may be removed from beneath or between crop and natural vegetation canopies depending on the width, height and distribution of cover types relative to wind direction and strength. Monitoring by repeated measurement or estimation of ground cover provides information to develop an understanding of its spatial and temporal variation. Fractional cover (fc) retrieved from optical satellite remote sensing (e.g., Moderate Resolution Imaging Spectroradiometer; MODIS) provides a consistent and repeatable measure of ground cover when viewed from above. Therefore, fc provides an areal assessment of components of ground cover. Fractional cover is consequently not the most appropriate approximation of the protection of the soil from wind erosion. Extant wind erosion model parameterisations of Lc already benefit from the use of satellite-derived cover data (Lfc). However, the parameterisations are not well developed. Here, we address the need for a dynamic (multitemporal), moderate resolution and global metric for wind erosion assessment and modelling. We demonstrate the benefits of using Lc within the context of monitoring ground cover for the assessment of wind erosion and review the basis for estimating ground cover using Lc. We describe a new method for an albedo-based approximation of aerodynamic sheltering (L{\textquoteright}). We use ray-casting of rough surfaces from an existing wind tunnel study to establish a relation between measured Lc and directional hemispherical reflectance {\textquoteright}dir(0{\textdegree},{\textquoteright}), the socalled {\textquoteleft}black-sky albedo{\textquoteright} and its inverse to estimate shadow. The relation is confirmed to be dependent on the solar zenith angle ({\textquoteright}) and spectral ({\textquoteright}) confounding factors (e.g., soil moisture, soil mineralogy). We reduced the {\textquoteright} dependency of {\textquoteright}dir(0{\textdegree},{\textquoteright}) by normalising with the MODIS (MCD43A1) BRDF parameter fiso to estimate albedobased lateral cover (L{\textquoteright}) globally over space (500 m pixels) and time (every 8 days). We compared L{\textquoteright} with fc and Lfc over time for selected locations in Australia and examined L{\textquoteright} across Australia and the USA using national biogeographic regions. Consistent with current approaches to estimating Lc, our results were not field validated due to the dearth of ground-based measurements. However, our results demonstrate that L{\textquoteright} will improve wind erosion models particularly over large areas and L{\textquoteright} is likely to be a valuable source of decision-support information to guide policy makers and land managers on where, when and how to reduce wind erosion.

}, doi = {10.1016/j.rse.2017.09.026}, url = {files/bibliography/18-005.pdf}, author = {A. Chappell and Nicholas Webb and Guerschman, J.P. and Dean Thomas and G. Mata and Handcock, R. and John Leys} } @article {JRN54949, title = {Innovation in rangeland monitoring: annual, 30 m, plant functional type percent cover maps for U.S. rangelands, 1984{\textendash}2017}, journal = {Ecosphere}, volume = {9}, year = {2018}, month = {09/2018}, pages = {1-19}, chapter = {1}, abstract = {

Innovations in machine learning and cloud-based computing were merged with historical
remote sensing and field data to provide the first moderate resolution, annual, percent cover maps of plant
functional types across rangeland ecosystems to effectively and efficiently respond to pressing challenges
facing conservation of biodiversity and ecosystem services. We utilized the historical Landsat satellite
record, gridded meteorology, abiotic land surface data, and over 30,000 field plots within a Random
Forests model to predict per-pixel percent cover of annual forbs and grasses, perennial forbs and grasses,
shrubs, and bare ground over the western United States from 1984 to 2017. Results were validated using
three independent collections of plot-level measurements, and resulting maps display land cover variation
in response to changes in climate, disturbance, and management. The maps, which will be updated annually
at the end of each year, provide exciting opportunities to expand and improve rangeland conservation,
monitoring, and management. The data open new doors for scientific investigation at an unprecedented
blend of temporal fidelity, spatial resolution, and geographic scale.

}, keywords = {cloud computing, conservation, Google Earth Engine, grazing, land cover, landsat, machine learning, rangeland, remote sensing, Time series, wildfire}, doi = {doi.org/10.1002/ecs2.2430}, url = {files/bibliography/18-021.pdf}, author = {Matthew O. Jones and Brady W. Allred and David E. Naugle and J. Maestas and Donnelly, Patrick and Loretta Metz and Jason W. Karl and Smith, Rob and Brandon T Bestelmeyer and Chad S. Boyd and Kerby, Jay D. and McIver, James D.} } @article {JRN55042, title = {The interactive role of wind and water in functioning of drylands: what does the future hold?}, journal = {BioScience}, volume = {68}, year = {2018}, month = {09/2018}, pages = {670-677}, chapter = {670}, abstract = {

Feedback mechanisms between abiotic and biotic processes in dryland ecosystems lead to a strong sensitivity to interannual variations in climate. Under a future regime of higher temperatures but potentially increased rainfall variability, drylands are anticipated to experience changes in wind and water transport that will alter plant community composition and feedback on landscape connectivity. Here, we present a conceptual framework for understanding the coupling of vegetation productivity, aeolian transport, and hydrologic connectivity under anticipated changes in future climate, which suggests that a more extreme climatic regime will lead to more connected landscapes with attendant losses in soil, nutrient, and water resources. When enhanced connectivity triggers state changes, irreversible changes in ecosystem functioning can occur, with implications for the future of global drylands.

}, keywords = {aeolian, connectivity, deserts, precipitation, runoff, wind erosion}, doi = {10.1093/biosci/biy067 }, url = {files/bibliography/JRN55042.pdf}, author = {Gregory S. Okin and O. E. Sala and Enrique Vivoni and J. Zhang and Abinash Bhattachan} } @proceedings {JRN54859, title = {Introducing version 5 of Interpreting Indicators of Rangeland Health}, volume = {January 28-February 2, 2018}, year = {2018}, month = {01/28/2018}, publisher = {Society for Range Management Meeting Proceedings}, address = {Reno, NV}, abstract = {

Interpreting Indicators of Rangeland Health was initiated in 1994 as a qualitative, rapid assessment technique to evaluate rangeland health. Seventeen field indicators are used to rate three attributes of rangeland health: 1) soil/site stability, 2) hydrologic function, and 3) biotic integrity. The published versions of this protocol are version 3 (2000) and version 4 (2005). \ Version 5 represents a continuing effort by an interagency cadre to improve the use of and consistency of results when using this protocol. The revision improves the development or modification of reference sheets and clarifies that the reference for conducting evaluations is the natural range of variability within the natural disturbance regime of the reference state. More emphasis is also placed on the functional/structural worksheet in conducting evaluations. This revision also supports linking qualitative and quantitative measurements, where quantitative measurements may also be used for baseline monitoring. A provisional copy of version 5 will be posted online and field-tested in 2018. Input from field tests will be incorporated into the published technical reference available in early 2019.

}, author = {M. Pellant and P. L. Shaver and D.A. Pyke and Jeffrey E. Herrick and F. Busby and Riegel, Gregg and Nika Lepak and David P. Toledo and Beth Newington and Emily Kachergis} } @conference {JRN54938, title = {Insights from Long-Term Ecological Research: free EcoTrends books available}, year = {2018}, month = {10/2018}, address = {Pacfic Grove, California}, abstract = {

EcoTrends is a project to synthesize long-term data to examine trends in the Earth{\textquoteright}s ecosystems. Participants in the data synthesis included scientists and information managers from 50 sites, including 25 LTER sites. The large and diverse collection of long-term ecological datasets can be found through the EcoTrends website (https://ecotrends.info/) or through our book (Peters et al. 2013), Our Changing World: Insights from Long-Term Ecological Research. This book is an excellent compendium of long-term ecological data and trends from long-term research sites.\  We have a small number of complimentary copies of our book available, and interested persons may sign up to have a free copy shipped to them.

}, author = {Debra C. Peters} } @article {JRN54926, title = {An integrated View of Complex Landscapes: A Big Data-Model Integration Approach to Transdisciplinary Science}, journal = {Bioscience}, volume = {68}, year = {2018}, month = {09/2018}, pages = {653-669}, chapter = {653}, abstract = {

The Earth is a complex system comprising many interacting spatial and temporal scales. We developed a transdisciplinary data-model integration (TDMI) approach to understand, predict, and manage for these complex dynamics that focuses on spatiotemporal modeling and cross-scale interactions. Our approach employs human-centered machine-learning strategies supported by a data science integration system (DSIS). Applied to ecological problems, our approach integrates knowledge and data on (a) biological processes, (b) spatial heterogeneity in the land surface template, and (c) variability in environmental drivers using data and knowledge drawn from multiple lines of evidence (i.e., observations, experimental manipulations, analytical and numerical models, products from imagery, conceptual model reasoning, and theory). We apply this transdisciplinary approach to a suite of increasingly complex ecologically relevant problems and then discuss how information management systems will need to evolve into DSIS to allow other transdisciplinary questions to be addressed in the future.

}, keywords = {cross-scale interactions, data science, earth science, landscape ecology, machine learning}, doi = {doi:10.1093/biosci/biy069}, url = {files/bibliography/18-015.pdf}, author = {Debra C. Peters and N. Dylan Burruss and Luis L Rodriguez and David McVey and Emile H. Elias and Angela Pelzel-McCluskey and J. D. Derner and Scott T. Schrader and Jin Yao and Steven J. Pauszek and Lombard, Jason and Steven R. Archer and Dawn M. Browning and Colby Brungard and J. Hatfield and Niall Hanan and Jeffrey E. Herrick and Gregory S. Okin and O. E. Sala and Heather Savoy and Enrique Vivoni and Brandon T Bestelmeyer} } @article {JRN54807, title = {Integrating remotely-sensed imagery and existing multi-scale field data to derive rangeland indicators: an application of Bayesian additive regression trees}, journal = {Rangeland Ecology and Management}, volume = {70}, year = {2017}, month = {09/2017}, pages = {644-655}, chapter = {644}, abstract = {

Remotely-sensed imagery at multiple spatial scales is used increasingly in conjunction with field data to estimate rangeland indicators (e.g., vegetation cover) and meet the growing need for landscape-scale monitoring and assessment of rangelands. Remote sensing studies that produce rangeland indicators often require intensive and costly field data collection efforts to produce accurate model predictions. Existing monitoring data, such as those collected by the Bureau of Land Management{\textquoteright}s Assessment, Inventory, and Monitoring (AIM) program, are potentially useful source of field data in remote sensing modeling studies. Due to the small sample sizes of typical AIM field projects compared to other remote sensing data collection efforts, common regression-tree-based modeling approaches may be inadequate for reliably predicting rangeland indicators with these training data. Bayesian models, such as Bayesian additive regression trees (BART), may provide a suitable alternative to traditional regression tree-based modeling approaches to overcome the sample size limitation of the AIM data. In this study, we used 182 AIM field plots together with both high (RapidEye) and moderate (Landsat OLI) spatial resolution satellite imagery to predict bare ground and bare soil, total foliar, herbaceous, woody, and shrub cover indictors on rangelands in a 14,625 km2 area of northeastern California. We demonstrate that a BART model performed similarly to other regression tree approaches when field data and high spatial resolution imagery predictions were combined to predict indicator values using the medium spatial resolution Landsat image. The BART models also provided spatially-explicit uncertainty estimates which allow land managers to more carefully evaluate indicator predictions and to identify areas where future field data collection might be most useful. This study demonstrates that existing field data and freely-available remotely-sensed imagery can be integrated to produce spatially explicit and continuous surface estimates of rangeland indicators across entire landscapes.

}, keywords = {Bayesian additive regression trees, BLM AIM, monitoring, rangelands, remote sensing}, doi = {doi:10.1016/j.rama.2017.02.004}, url = {files/bibliography/17-025.pdf}, author = {Sarah McCord and M. Buenemann and Jason W. Karl and Dawn M. Browning and Hadley, Brian} } @article {JRN54803, title = {The interactive effects of press/pulse intensity and duration on regime shifts at multiple scales}, journal = {Ecological Monographs}, volume = {87}, year = {2017}, month = {05/2017}, pages = {198-218}, chapter = {198}, abstract = {

Regime shifts are difficult-to-reverse transitions that occur when an ecosystem reorganizes around a new set of self-reinforcing feedbacks. Regime shifts are predicted to occur when the intensity of some exogenous driver variable, such as temperature, annual harvest rate, or nutrient addition rate, gradually approaches and crosses a threshold value, initiating a transition to an alternative state. However, many driver variables now change rapidly as presses or pulses, not gradually, requiring new conceptual frameworks for understanding and predicting regime shifts. We argue that identifying and controlling regime shifts in response to presses and pulses will require a greater focus on the duration, not just the intensity, of changes in driver variables. In ecosystems with slower dynamics, transitions to an alternative state can take years to decades and as a result, a driver press with an intensity capable of resulting in a regime shift over long time spans may fail to cause a regime shift when applied for shorter durations. We illustrate these ideas using simulations of local-scale alternative stable state models and preliminary evidence from long-term grazing and eutrophication experiments. The simulations also suggest that small changes in the duration of driver presses or pulses can determine whether an ecosystem recovers to its original state. These insights may extend to larger scales. In spatially extended simulations that included patchiness, spatial heterogeneity, and spatial connectivity, all patches recovered to their original state after shorter presses. However, once press duration exceeded a threshold, growing proportions of the landscape shifted to an alternative state as press duration increased. We observed similar patchy transitions in a catchment-scale experiment that reinstated frequent fires approximately halfway through a regime shift from grassland to shrubland, initiated by fire suppression. In both the local- and larger-scale models, the threshold duration needed to elicit regime shifts decreased as press intensity increased or when factors counteracting regime shifts weakened. These multiple lines of evidence suggest that conceptualizing regime shifts as an interactive function of the intensity and duration of driver changes will increase understanding of the varying effects of driver presses, pulses, and cycles on ecosystem dynamics.

}, keywords = {alternative stable states, bistability, catastrophic shifts, critical transitions, extreme events, invasive species, non-equilibrium, resilience, restoration, tiping points, transience}, doi = {doi:10.1002/ecm.1249}, url = {files/bibliography/17-020_0.pdf}, author = {Ratajczak, Zak and Paolo D{\textquoteright}Odorico and S.L. Collins and Brandon T Bestelmeyer and Isbell, Forest and Jesse Nippert} } @conference {JRN54784, title = {Insights on drought and long-term climatic trends: Retrospective analyses of RMA cause of loss data}, booktitle = {University Council on Water Resources / National Institute of Water Resources Annual Conference}, year = {2017}, month = {06/2017}, publisher = {University Council on Water Resources / National Institute of Water Resources}, organization = {University Council on Water Resources / National Institute of Water Resources}, address = {Fort Collins, CO}, abstract = {

A modern trend among federal agencies, funding streams, and research projects involves the synthesis of existing data to increase the overall collective value and meaning of such knowledge. The creation of the U.S. Department of Agriculture (USDA) Climate Hubs follows this line of thought with information synthesis and tool development as tangible outputs of this new federal coordination network. The Hubs{\textquoteright} mission is to develop and deliver science-based information and technologies to agricultural and natural resource managers to enable climate-informed decision-making. As part of this, Hubs work across USDA agencies to synthesize existing information to meet the needs of our stakeholders. The USDA Risk Management Agency (RMA) is responsible for overseeing the Federal crop insurance program and works with private insurance companies. The USDA also administers other programs for commodities not insured under the federal program such as for livestock and honey bees. RMA has collected annual cause of loss data since the mid-1900s with monthly data beginning in 1989. These data describe the reason for loss (e.g. drought, wind, irrigation failure), indemnity amount (i.e. total cost of loss), insurance plan code, as well as relevant spatio-temporal information (i.e. state, county, year, month). \ The objective of this paper is to link climate information with cause of loss data to potentially shape the development of future RMA programs and provide regionally-relevant information to our stakeholders to effectively manage their lands. We describe an initial retrospective analysis at various spatial scales by land use/land cover, ecoregions, climate zones, and geopolitical boundaries. In addition, we link historical weather data (precipitation and temperature) with causes of loss at multiple time steps: monthly, annual, and decadal. Ultimately this analysis will convey county-level trends to support informed land management decisions and ecosystem resilience.\ 

}, author = {J.T. Reyes and Andrew Eischens and Shilts, Mark and Emile H. Elias and Rachel Steele} } @conference {JRN54816, title = {Insights on drought and long-term climatic trends: Retrospective analyses of crop insurance data}, 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 = {

A modern trend among federal agencies, funding streams, and research projects involves the synthesis of existing data to increase the overall collective value and meaning of such knowledge. The creation of the U.S. Department of Agriculture (USDA) Climate Hubs follows this line of thought with information synthesis and tool development as tangible outputs of this new federal coordination network. The Hubs{\textquoteright} mission is to develop and deliver science-based information and technologies to agricultural and natural resource managers to enable climate-informed decision-making. As part of this, Hubs work across USDA agencies to synthesize existing information to meet the needs of our stakeholders. \ \ 

The USDA Risk Management Agency (RMA) is responsible for overseeing the Federal crop insurance program and works with private insurance companies. The USDA also administers other programs for commodities not insured under the federal program such as for livestock and honey bees. RMA has collected annual cause of loss data since the mid-1900s with monthly data beginning in 1989. These data describe the reason for loss (e.g. drought, wind, irrigation failure), indemnity amount (i.e. total cost of loss), as well as relevant spatio-temporal information (i.e. state, county, year, month).

The objective of this paper is to link climate information with indemnities and their associated cause of loss to potentially shape the development of future RMA programs and provide regionally-relevant information to our stakeholders to effectively manage their lands. We describe an initial retrospective trend analysis at the state-level for the American Southwest. In addition, we link historical monthly weather data (i.e. precipitation and temperature) and long-term drought indices (e.g. Palmer Drought Severity Index) with indemnities grouped by different causes of loss. Ultimately this analysis will convey county-level spatial and temporal trends via a web-based information browser to support informed land management decisions and ecosystem resilience.

}, author = {J.T. Reyes and Andrew Eischens and Shilts, Mark and Emile H. Elias and Rachel Steele} } @article {JRN54824, title = {Isolation predicts compositional change after discrete disturbances in a global meta-study}, journal = {Ecography}, volume = {40}, year = {2017}, pages = {1256-1266}, chapter = {1256}, abstract = {

Globally, anthropogenic disturbances are occurring at unprecedented rates and over extensive spatial and temporal scales. Human activities also affect natural disturbances, prompting shifts in their timing and intensities. Thus, there is an urgent need to understand and predict the response of ecosystems to disturbance. In this study, we investigated whether there are general determinants of community response to disturbance across different community types, locations, and disturbance events. We compiled 14 case studies of community response to disturbance from four continents, twelve aquatic and terrestrial ecosystem types, and eight different types of disturbance. We used community compositional differences and species richness to indicate community response. We used mixed-effects modeling to test the relationship between each of these response metrics and four potential explanatory factors: regional species pool size, isolation, number of generations passed, and relative disturbance intensity. We found that compositional similarity was higher between pre- and post-disturbance communities when the disturbed community was connected to adjacent undisturbed habitat. The number of generations that had passed since the disturbance event was a significant, but weak, predictor of community compositional change; two communities were responsible for the observed relationship. We found no significant relationships between the factors we tested and changes in species richness. To our knowledge, this is the first attempt to search for general drivers of community resilience from a diverse set of case studies. The strength of the relationship between compositional change and isolation suggests that it may be informative in resilience research and biodiversity management.

}, doi = {10.1111/ecog.02383}, url = {/files/bibliography/17-031.pdf}, author = {Shackelford, Nancy and Starzomski, B.M. and Banning, Natasha C. and Battaglia, Loretta and Becker, Alistair and Bellingham, P.J. and Brandon T Bestelmeyer and Catford, Jane A. and John M. Dwyer and Dynesius, Mats and Gilmour, James and Hallett, Lauren M. and Richard J. Hobbs and Price, Jodi N. and Sasaki,Takehiro and Tanner, Edmund V.J. and Standish, Rachel} } @article {JRN54584, title = {Impact of land surface states within the flux footprint on daytime land-atmosphere coupling in two semiarid ecosystems of the Southwestern U.S.}, journal = {Water Resources Research}, volume = {52}, year = {2016}, abstract = {

Land surface states play important roles in the turbulent exchanges between ecosystems and their overlying atmosphere. Field methods to estimate turbulent fluxes have time-variable source areas, while land surface observations are typically obtained at single plots with a smaller measurement scale. In this study, we characterize land-atmosphere interactions in two semiarid ecosystems in the southwestern U.S. At each study site, we combine the eddy covariance method with a distributed network of soil moisture and temperature sensors, high-resolution imagery of the spatial distribution of vegetation and soil patches, and novel spatiotemporal analyses to characterize the turbulent flux footprint analytically and identify the soil moisture, temperature, and vegetation conditions underlying the eddy covariance measurements. Four methods for aggregating the land surface observations to the scale of the daily flux footprint are tested. Our results reveal a large degree of spatial variability in the footprint, with stronger variations in soil moisture than in soil temperature. Single plot measurements are less reliable than the distributed network in capturing footprint conditions, particularly for soil moisture. Furthermore, a marked improvement is observed in the relations between turbulent fluxes and land surface states for methods capturing the footprint variability. We also identify that the composition of vegetation and soil patches in the time-variable source area affects the relative magnitudes of the turbulent fluxes and the partitioning of evapotranspiration. Our study points to the importance of monitoring the spatial distribution of land surface states (e.g., soil moisture and temperature) and vegetation and soil patches when assessing land-atmosphere interactions.

}, keywords = {eddy covariance, evapotranspiration, land surface variability, turbulent fluxes}, doi = {10.1002/2015WR018016}, url = {files/bibliography/JRN00650.pdf}, author = {C.A. Anderson and Enrique Vivoni} } @article {JRN54697, title = {Improving the effectiveness of ecological site descriptions: General state-and-transition models and the Ecosystem Dynamics Interpretive Tool (EDIT)}, journal = {Rangelands}, volume = {38:329-335}, year = {2016}, type = {12/2016}, abstract = {

State-and-transition models (STMs) were conceived as a means to organize and communicate information about ecosystem changes and how to manage them. Information within STMs applies to ecological land classes, such as ecological sites, that possess similar vegetation states. The value of STMs for rangeland managers is in fostering a general understanding of how rangelands function and respond to management actions, thereby leading to more efficient and effective allocation of management efforts. \ STMs can play an important role in most steps of conservation planning.

}, doi = {10.1016/j.rala.2016.10.001}, url = {files/bibliography/16-034.pdf}, author = {Brandon T Bestelmeyer and Jebediah C. Williamson and Curtis Talbot and Cates, Greg and Danielle Duni and Joel R. Brown} } @article {JRN54696, title = {An Introduction to the Special Issue {\textquotedblleft}Ecological Sites for Landscape Management"}, journal = {Rangelands}, volume = {38}, year = {2016}, month = {12/2016}, abstract = {

The December 2010 Rangelands {\textquotedblleft}Ecological Site Descriptions{\textquotedblright} \ was one of the most widely read issues ever published. The individual papers have been used by scientists, managers, policymakers, and educators to convey the importance of ecological site information to natural resource management and to improve understanding of this tool. The issue was successful in providing a focal point for a widely dispersed literature and practice by bringing together historical perspective, terminology, general guidance, and applications to a variety of range and forest ecosystems. At the time of the previous special issue on ecological sites, the three predominant land management agencies in the United States (Bureau of Land Management, U.S. Forest Service, and Natural Resources Conservation Service) had just signed the Interagency Memorandum of Understanding; the Interagency Rangeland Ecological Site Manual was about to be released and individual agencies were realigning inventory and monitoring programs and staffs.

}, doi = {10.1016/j.rala.2016.11.001}, url = {files/bibliography/16-033.pdf}, author = {Joel R. Brown and Brandon T Bestelmeyer} } @conference {JRN54610, title = {Impact of climate change on projected runoff from mountain snowpack of the King{\textquoteright}s Rivershed in California}, booktitle = {American Geophysical Union}, year = {2016}, month = {12/2016}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {San Francisco}, abstract = {
The Central Valley of California, like most dryland agricultural areas in the Southwest United States, relies heavily on winter snowpack for water resources. Projections of future climate in the Sierra Mountains of California calls for a warmer climate regime that will impact the snowpack in the Sierra Mountains and thus the water supply for downstream agriculture and municipal uses within California{\textquoteright}s Central Valley. We simulate the impacts of two future time windows (2040-2069 and 2070-2099) and two future climate scenarios (RCP 4.5 and 8.5) on King{\textquoteright}s River using the Snowmelt Runoff Model. Snow depletion curves for 2010 are generated using MODIS and SRM parameters are adjusted until measured and simulated runoff reach acceptable agreement (R2 = .81). Future projections are based upon the multimodel mean of 20 CMIP5 models for seasonal future temperature and precipitation at high and low elevation points in the watershed from the multivariate adaptive constructed analogs (MACA) downscaled dataset. Changes in monthly inflow to Pineflat Reservoir, at the pour point of King{\textquoteright}s River watersheds, show a large decline in June and July inflow for all future climate simulations. Conversely, simulated spring inflow to Pineflat Reservoir is larger in the future. Impacts are most pronounced for end of the century (2070-2099), business as usual (RCP 8.5) simulation. Results are discussed with regard to implications for reservoir storage, groundwater recharge and creative solutions to cope with anticipated changes in runoff.\ 
}, author = {Jake Dialesandro and Emile H. Elias and Caitriana Steele and A. Rango} } @conference {JRN54619, title = {Impact of climate change on projected runoff from mountain snowpack of the King{\textquoteright}s Rivershed in California}, booktitle = {American Geophysical Union}, year = {2016}, month = {12/2016}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {San Francisco, CA}, abstract = {
The Central Valley of California, like most dryland agricultural areas in the Southwest United States, relies heavily on winter snowpack for water resources. Projections of future climate in the Sierra Mountains of California calls for a warmer climate regime that will impact the snowpack in the Sierra Mountains and thus the water supply for downstream agriculture and municipal uses within California{\textquoteright}s Central Valley. We simulate the impacts of two future time windows (2040-2069 and 2070-2099) and two future climate scenarios (RCP 4.5 and 8.5) on King{\textquoteright}s River using the Snowmelt Runoff Model. Snow depletion curves for 2010 are generated using MODIS and SRM parameters are adjusted until measured and simulated runoff reach acceptable agreement (R2 = .81). Future projections are based upon the multimodel mean of 20 CMIP5 models for seasonal future temperature and precipitation at high and low elevation points in the watershed from the multivariate adaptive constructed analogs (MACA) downscaled dataset. Changes in monthly inflow to Pineflat Reservoir, at the pour point of King{\textquoteright}s River watersheds, show a large decline in June and July inflow for all future climate simulations. Conversely, simulated spring inflow to Pineflat Reservoir is larger in the future. Impacts are most pronounced for end of the century (2070-2099), business as usual (RCP 8.5) simulation. Results are discussed with regard to implications for reservoir storage, groundwater recharge and creative solutions to cope with anticipated changes in runoff.\ 
}, author = {Jake Dialesandro and Emile H. Elias and Caitriana Steele and A. Rango} } @article {JRN54502, title = {Impacts of forest to urban land conversion and ENSO phase on water quality of a public water supply reservoir}, journal = {Forests}, volume = {3}, year = {2016}, month = {01/2016}, abstract = {

We used coupled watershed and reservoir models to evaluate the impacts of deforestation and ENSO phase on drinking water quality. Source water total organic carbon (TOC) is especially important due to the potential for production of carcinogenic disinfection byproducts (DBPs). The Environmental Fluid Dynamics Code (EFDC) reservoir model is used to evaluate the difference between daily pre- and post- urbanization nutrients and TOC concentration. Post-disturbance (future) reservoir TN, TP, TOC and chlorophyll-a concentrations were found to be higher than pre-urbanization (base) concentrations (p\<0.05). Predicted future median TOC concentration was 1.1 mg L-1 (41\% higher than base TOC concentration) at the source water intake. Simulations show that prior to urbanization, additional water treatment was necessary on 47\% of the days between May and October. However, following simulated urbanization, additional drinking water treatment might be continuously necessary between May and October. One of six ENSO indices is weakly negatively correlated with the measured reservoir TOC indicating there may be higher TOC concentrations in times of lower streamflow (La Ni{\~n}a). There is a positive significant correlation between simulated TN and TP concentrations with ENSO suggesting higher concentrations during El Ni{\~n}o.

}, keywords = {deforestation, drinking water treatment, eservoir model, total organic carbon disinfection byproducts; ENSO, urbanization}, doi = {10.3390/f7020029}, url = {/files/bibliography/16-003.pdf}, author = {Emile H. Elias and Rodriguez, Hugo and Srivastava, Puneet and Dougherty, Mark and D. K. James and Ryann Smith} } @conference {JRN54612, title = {Integrating legacy data to understand agroecosystem regional dynamics to catastrophic events}, booktitle = {American Geophysical Union Fall Meeting }, year = {2016}, month = {12/2016}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {San Francisco, CA}, abstract = {
Multi-year extreme drought events are part of the history of the Earth system. Legacy data on the climate drivers, geomorphic features, and agroecosystem responses across a dynamically changing landscape throughout a region can provide important insights to a future where large-scale catastrophic events may occur more frequently. One of the most devastating multi-year droughts occurred in the central grasslands region of North America in the 1930s. This regional-scale climatic event combined with land management practices to result in broad-scale plant mortality and massive dust storms that impacted the entire continent. However, not all areas were affected similarly, even across relatively short distances with similar climate, soils, and land management. Spatial discontinuities in impacts occurred across a 100-km transition from high plant mortality and high rates of soil erosion in eastern Nebraska to areas in western Iowa with reductions in grass cover and biomass, but low rates of plant mortality and erosion. Because this time period preceded modern agriculture and the extensive plowing of native tallgrass prairie, the landscape was composed of both native prairie grassland and cropland. Responses were compared during the drought to responses for the same region in the 1920s (pre-drought) and the 1940s (post-drought). A large number of legacy datasets from the U.S. Department of Agriculture and other sources were spatially integrated to test two hypotheses: (1) local factors of climate and soil properties explained agroecosystem responses in the pre- and post-drought periods, (2) local factors were insufficient to explain agroecosystem responses during the multi-year drought. Analyses supported these hypotheses and found that landscape features, such as large alluvial plains that reduced connectivity by sand and deposition by wind, were more important than local factors to explain different responses along the gradient during the drought. Similar results were found for both native grassland and cropland. These findings have important implications for landscape configurations and connectivity in the face of large-scale, extreme events.\ 
}, author = {Debra C. Peters and N. Dylan Burruss and Jin Yao and Gregory S. Okin and Stacey L P Scroggs and Curtis H. Monger and Kris Havstad} } @article {JRN54475, title = {Incorporating hydrologic data and ecohydrologic relationships into ecological site descriptions}, journal = {Rangeland Ecology and Management}, volume = {69}, year = {2016}, month = {01/2016}, pages = {4-19}, chapter = {4}, abstract = {

The purpose of this paper is to recommend a framework and methodology for incorporating hydrologic data and ecohydrologic relationships in Ecological Site Descriptions (ESDs) and thereby enhance the utility of ESDs for assessing rangelands and guiding resilience-based management strategies. Resilience-based strategies assess and manage ecological state dynamics that affect state vulnerability and, therefore, provide opportunities to adapt management. Many rangelands are spatially heterogeneous or sparsely vegetated where the vegetation structure strongly influences infiltration and soil retention. Infiltration and soil retention further influence soil water recharge, nutrient availability, and overall plant productivity. These key ecohydrologic relationships govern the ecologic resilience of the various states and community phases on many rangeland ecological sites (ESs) and are strongly affected by management practices, land use, and disturbances. However, ecohydrologic data and relationships are often missing in ESDs and state-and-transition models (STMs). To address this void, we used literature to determine the data required for inclusion of key ecohydrologic feedbacks into ESDs, developed a framework and methodology for data integration within the current ESD structure, and applied the framework to a select ES for demonstrative purposes. We also evaluated the utility of the Rangeland Hydrology and Erosion Model (RHEM) for assessment and enhancement of ESDs based in part on hydrologic function. We present the framework as a broadly applicable methodology for integrating ecohydrologic relationships and feedbacks into ESDs and resilience-based management strategies. Our proposed framework increases the utility of ESDs to assess rangelands, target conservation and restoration practices, and predict ecosystem responses management. The integration of RHEM technology and our suggested framework on ecohydrologic relations expands the ecological foundation of the overall ESD concept for rangeland management and is well aligned with resilience-based, adaptive management of US rangelands. The proposed enhancement of ESDs will improve communication between private land owners and resource managers and researchers across multiple disciplines in the field of rangeland management.

}, keywords = {adaptive management, ecological site, erosion, infiltration, monitoring, multiple stable states, rangeland, rangeland health, Rangeland Hydrology and Erosion Model, resilience, runoff state-and-transition models}, doi = {10.1016/j.rama.2015.10.001}, url = {/files/bibliography/16-001.pdf}, author = {Jason C. Williams and Frederick B. Pierson and K. Spaeth and Joel R. Brown and Al-Hamdan, Osama Z. and M.A. Weltz and Mark A. Nearing and Jeffrey E. Herrick and Boll, Jan and Robichaud, Peter R. and David C. Goodrich and Phil Heilman and Guertin, D. Phillip and Mariano Hernandez and Wei, Haiyan and Stuart P. Hardegree and Strand, Eva K. and Bates, Jonathan D. and Loretta Metz and M. H. Nichols} } @conference {JRN54416, title = {Impact of climate change on water quality of an impaired New Mexico river}, booktitle = {New Mexico Water Conference}, year = {2015}, month = {10/2015}, address = {Taos, NM}, abstract = {

Climate change is predicted to advance runoff timing in snowmelt basins and decrease available water, particularly in arid and semi-arid regions. Researchers have suggested that the impacts of climate change will degrade water quality by reducing dilution. We use coupled snowmelt and water quality models to quantify the impacts of climate change on the Chama River, a New Mexico waterbody presently impaired to temperature, nutrients and pathogens. We use the Snowmelt Runoff Model and downscaled temperature and precipitation to simulate the impacts of a statistically selected range of future climate conditions (warmer/wetter; warmer/drier; hotter/wetter; hotter/drier) on streamflow. SRM streamflow for base and future scenarios is coupled with a water quality model (LOADEST) to evaluate the impacts of climate change on water quality. There is a shift in timing of the delivery of water quality loads with more early small peaks during autumn and winter and an earlier and lower peak in snow melt runoff loads. The impacts of climate change vary by hydrograph phase, with higher loads during baseflow, particularly for the hotter/wetter simulation, but lower loads during snowmelt runoff for all parameters. Water quality responses vary by parameter and year, indicating a range of impacts of climate change on water quality which should be evaluated separately for each parameter. Abstract $\#$40.

}, author = {Emile H. Elias and D. K. James and A. Rango and Caitriana Steele and Ryann Smith and Mejia, John} } @conference {JRN54408, title = {Impacts of climate change on Southwestern working lands and water resources: a report from the inaugural year of the USDA Southwest climate hub}, booktitle = {2015 UCOWR / NIWR / CUAHSI Annual Conference}, year = {2015}, month = {06/2015}, address = {Henderson, NV}, abstract = {

In February 2014 the USDA established seven regional climate hubs to assist farmers, ranchers and foresters in adapting to the effects of climate change.\  The SW region encompasses six states (including Hawaii) and provides highly diverse agricultural crops including cotton, stone fruit and grapes.\  The SW relies on irrigation more heavily than any other in the US and water supplies are critical to meeting regional irrigation needs. In addition, seasonal and annual rainfall amounts dictate livestock numbers regional rangelands can support.\  Projected future temperatures by mid-century indicate a 2 to 4{\textdegree}C average annual temperature increase across the region.\  This increase will further limit presently scarce water resources by increasing regional evaporation and transpiration.\  Models predict that drought and water competition will likely be a more frequent reality in future.\ \ \  To help SW working land owners cope with the impacts of climate change, the Hub has established formal agreements with Cooperative Extension and hosted regional climate change workshops.\  The Hub funded development of a climate change module for regional rural and urban schools.\ \  Hub staff drafted a Vulnerability Assessment of SW crops, animal agriculture and forests to climate change.\  Vulnerability to climate change is generally defined in terms of exposure, sensitivity and adaptive capacity.\  Given temperature increases and reduced winter chilling hours, certain crops will have likely have reduced yields while others, given adequate water, will be less effected.\  Similarly, certain livestock and geographic regions are more vulnerable to projected climate change. Water is a critical component of agricultural vulnerability in the SW and results are presented from a hydrologic perspective.

}, author = {Emile H. Elias and A. Rango and Kris Havstad and Caitriana Steele} } @conference {JRN54508, title = {Impacts of projected mid-century temperatures on thermal regimes for select specialty and fieldcrops common to the southwestern U.S.}, booktitle = {American Geophysical Union Fall Meeting}, year = {2015}, month = {12/2015}, publisher = {AGU}, organization = {AGU}, address = {San Francisco, CA}, abstract = {

The impacts of projected temperature increases in agricultural ecosystems are complex, varying by region, cropping system, crop growth stage and humidity. We analyze the impacts of mid-century temperature increases on crops grown in five southwestern states: Arizona, California, New Mexico, Nevada and Utah. Here we present a spatial impact assessment of common southwestern specialty (grapes, almonds and tomatoes) and field (alfalfa, cotton and corn) crops. This analysis includes three main components: development of empirical temperature thresholds for each crop, classification of predicted future climate conditions according to these thresholds, and mapping the probable impacts of these climatic changes on each crop. We use 30m spatial resolution 2012 crop distribution and seasonal minimum and maximum temperature normals (1970 to 2000) to define the current thermal envelopes for each crop. These represent the temperature range for each season where 95\% of each crop is presently grown. Seasonal period change analysis of mid-century temperatures changes downscaled from 20 CMIP5 models (RCP8.5) estimate future temperatures. Change detection maps represent areas predicted to become more or less suitable, or remain unchanged. Based upon mid-century temperature changes, total regional suitable area declined for all crops except cotton, which increased by 20\%. For each crop there are locations which change to and from optimal thermal envelope conditions. More than 80\% of the acres currently growing tomatoes and almonds will shift outside the present 95\% thermal range. Fewer acres currently growing alfalfa (14\%) and cotton (20\%) will shift outside the present 95\% thermal range by midcentury. Crops outside present thermal envelopes by midcentury may adapt, possibly aided by adaptation technologies such as misters or shade structures, to the new temperature regime or growers may elect to grow alternate crops better suited to future thermal envelopes.

}, author = {Richard E. Estell and Brody-Lopez, Nathan and Jake Dialesandro and Caitriana Steele and A. Rango} } @conference {JRN54444, title = {Implementing AIM-based monitoring for natural resource management}, booktitle = {68th Annual Meeting of the Society for Range Management}, year = {2015}, month = {02/2015}, publisher = {Sociiety for Range Management}, organization = {Sociiety for Range Management}, address = {Sacramento, CA}, abstract = {

Successful monitoring programs are built on clearly-defined objectives, thorough planning, and organized implementation. However, natural resource management decisions need to be made at many different organizational levels and scales {\textendash} from local to national. Developing separate monitoring programs to address each of these levels can be an inefficient and costly approach. We present the monitoring process model that is used for design and implementation of Bureau of Land Management{\textquoteright}s (BLM) Assessment, Inventory, and Monitoring (AIM) monitoring projects. The AIM program provides a framework for collecting monitoring data which can be used many times for many objectives (e.g., land health assessments, Sage-grouse [Centrocercus urophasianus] habitat monitoring, grazing management). This framework places an emphasis on designing and implementing robust monitoring programs. While coordinated monitoring across scales is not always possible, the basic AIM principles (standardized core indicators and methods, statistically-valid sample designs, effective data management, and thorough documentation of the monitoring process) facilitate the use of monitoring data to answer the original objectives and allow for merging of monitoring data between efforts to meet additional objectives. The AIM monitoring implementation framework breaks the development and implementation of monitoring down into a series of achievable, iterative and documentable steps. These steps include: developing management and monitoring objectives; defining the monitoring area, stratification approach, and reporting requirements; selecting indicators and methods; developing data management and quality assurance/control procedures; establishing monitoring locations and collecting and evaluating monitoring data; and analyzing and interpreting monitoring results. Further, we discuss the various roles and skills needed for implementing a monitoring program. We illustrate the implementation steps and roles with examples from AIM projects in northern California and southern Idaho designed to inform land health assessments and evaluations of Sage-grouse habitat. Finally, we showcase tools, databases, and best practices available to assist in implementing AIM monitoring.

}, author = {D. K. James and Sarah McCord and Emily Kachergis and Jeffrey E. Herrick} } @article {JRN54169, title = {In-situ measurement of dust devil activity at La Jornada Experimental Range, New Mexico, USA}, journal = {Aeolian Research}, year = {2015}, pages = {1-12}, abstract = {

We document observations of dust devil vortices using a linear array of 10 miniature pressure- and sunlight-logging stations in summer 2013 at La Jornada Experimental Range in the southwestern USA. These data provide a census of vortex and dust-devil activity at this site. The simultaneous spatially-distributed measurements resolve the horizontal pressure structure of several dust devil encounters, and the data can be fit well with an analytic model, giving independent measures of vortex size and intensity.

}, keywords = {dust devils, meteorology, power law, vortex structure}, doi = {10.1016/j.aeolia.2015.01.012}, url = {/files/bibliography/15-026.pdf}, author = {Ralph D. Lorenz and Lynn D. Neakrase and John P. Anderson} } @article {JRN52695, title = {Interactions among resource partitioning, sampling effect, and facilitation on the biodiversity effect: a modeling approach}, journal = {Oecologia}, volume = {174}, year = {2014}, pages = {559-566}, abstract = {

Resource partitioning, facilitation, and sampling effect are the three mechanisms behind the biodiversity effect, which is depicted usually as the effect of plantspecies richness on aboveground net primary production. These mechanisms operate simultaneously but their relative importance and interactions are difficult to unravel experimentally. Thus, niche differentiation and facilitation have been lumped together and separated from the sampling effect. Here, we propose three hypotheses about interactions among the three mechanisms and test them using a simulation model. The model simulated water movement through soil and vegetation, and net primary production mimicking the Patagonian steppe. Using the model, we created grass and shrub monocultures and mixtures, controlled root overlap and grass water-use efficiency (WUE) to simulate gradients of biodiversity, resource partitioning and facilitation. The presence of shrubs facilitated grass growth by increasing its WUE and in turn increased the sampling effect, whereas root overlap (resource partitioning) had, on average, no effect on sampling effect. Interestingly, resource partitioning and facilitation interacted so the effect of facilitation on sampling effect decreased as resource partitioning increased. Sampling effect was enhanced by the difference between the two functional groups in their efficiency in using resources. Morphological and physiological differences make one group outperform the other; once these differences were established further differences did not enhance the sampling effect. In addition, grass WUE and root overlap positively influence the biodiversity effect but showed no interactions.

}, keywords = {biodiversity and ecosystem functioning, facilitation, model, net primary production model, NPP model, Patagonian steppe, resource partitioning, sampling effect, water movement}, issn = {0029-8549}, doi = {10.1007/s00442-013-2775-8 }, url = {files/bibliography/JRN00627.pdf}, author = {P. Flombaum and O. E. Sala and E. B. Rastetter} } @proceedings {JRN54574, title = {Investigating biochar as a tool for mine soil remediation}, year = {2014}, month = {08/2014}, publisher = {National Conference on Mining-Influenced Waters}, address = {Albuquerque, New Mexico}, abstract = {Biochar is a cost-effective, carbon negative soil amendment that can lead to improved soil quality. Research has also demonstrated the efficacy of biochar to sorb heavy metals and agricultural chemicals from contaminated soils, thus effectively reducing the potential for metal and chemical contamination of surface and ground waters. In this study we investigated the ability of biochar produced from a single feedstock (Doulas fir wood chips) across a range of charring temperatures (300 {\textendash} 700 {\textdegree}C) to bind with metals. Our goal in this research is to link metal sorption to specific biochar properties, and then use these relationships to engineer biochar with specific properties to achieve various remediation and soil quality outcomes. We characterized our biochars using a variety of techniques including total elemental analysis, pH, FTIR spectroscopy, surface area and pore size analysis, and proximal carbon analysis. We used batch experiments of biochar with either Cu (II) solutions or simulated rainwater extracts of soils contaminated with mine tailings to investigate metal sorption. Sorbed metals were characterized using synchrotron-based XAS, XANES, EXAFS and XRF-Tomography. We found that higher temperature biochars, while having a decreased abundance of oxygen containing functional groups, had an increased capacity for metal sorption over biochar produced at lower temperatures. Concomitantly, these biochars also have greater ash contents, surface areas, abundance of small pores and higher pH values. Results of our sorption studies indicate that metal sorption on biochar may be competitive and preferential, and that as the charring temperature goes up, physisorption may become more important as a mechanism of metal sorption to biochar. }, author = {Mark Johnson and Jonathan Maynard and Nico, Peter} } @article {JRN53965, title = {Interpretation of high-resolution imagery for detecting vegetation cover composition change after fuels reduction treatments in woodlands}, journal = {Ecological Indicators}, volume = {45}, year = {2014}, month = {06/2014}, pages = {570-578}, chapter = {570}, abstract = {

The use of very high resolution (VHR; ground sampling distances \< ~5cm) aerial imagery to estimate site vegetation cover and to detect changes from management has been well documented. However, as the purpose of monitoring is to document change over time, the ability to detect changes from imagery at the same or better level of accuracy and precision as those measured in situ must be assessed for image-based techniques to become reliable tools for ecosystem monitoring. Our objective with this study was to quantify the relationship between field-measured and image-interpreted changes in vegetation and ground cover measured one year apart in a Pi{\~n}on and Juniper (P-J) woodland in southern Utah, USA. The study area was subject to a variety of fuel removal treatments between 2009 and 2010. We measured changes in plant community composition and ground cover along transects in a control area and three different treatments prior to and following P-J removal. We compared these measurements to vegetation composition and change based on photo-interpretation of ~4 cm ground sampling distance imagery along similar transects. Estimates of cover were similar between field-based and image-interpreted methods in 2009 and 2010 for woody vegetation, no vegetation, herbaceous vegetation, and litter (including woody litter). Image-interpretation slightly overestimated cover for woody vegetation and no-vegetation classes (average difference between methods of 1.34\% and 5.85\%) and tended to underestimate cover for herbaceous vegetation and litter (average difference of -5.18\% and 0.27\%), but the differences were significant only for litter cover in 2009. Level of agreement between the field-measurements and image-interpretation was good for woody vegetation and no-vegetation classes (r between 0.47 and 0.89), but generally poorer for herbaceous vegetation and litter (r between 0.18 and 0.81) likely due to differences in image quality by year and the difficulty in discriminating fine vegetation and litter in imagery. Our results show that image interpretation to detect vegetation changes has utility for monitoring fuels reduction treatments in terms of woody vegetation and no-vegetation classes. The benefits of this technique are that it provides objective and repeatable measurements of site conditions that could be implemented relatively inexpensively and easily without the need for highly specialized software or technical expertise. Perhaps the biggest limitations of image interpretation to monitoring fuels treatments are challenges in estimating litter and herbaceous vegetation cover and the sensitivity of herbaceous cover estimates to image quality and shadowing.

}, keywords = {change detection, high-resolution, image interpretation, land cover, rangeland monitoring, remote sensing}, doi = {10.1016/j.ecolind.2014.05.017}, url = {/files/bibliography/14-017.pdf}, author = {Jason W. Karl and Jeffrey K. Gillan and N. Barger and Jeffrey E. Herrick and Danielle Duni} } @article {JRN54659, title = {An integrated approach to grazingland ecological assessments and management interpretations}, journal = {Journal of Soil and Water Conservation}, volume = {69(4):110A-114A}, year = {2014}, month = {06/2014}, abstract = {

The status of grazinglands in the USA is increasingly dynamic with large areas being converted to cropland in response to demands for increased crop production. Here we focus on two types of grazinglands: rangelands and pasturelands. Rangelands are usually defined as natural ecosystems in which the native vegetation is predominantly grasses, grass-like plants or shrubs, and are generally used for grazing livestock and wildlife. Pasturelands are areas specifically managed for the production of forage (native or introduced) for grazing livestock. In the USA, rangelands and pasturelands have traditionally been assessed using different methods and indicators. These differences in assessment methods limit the ability to consistently apply land evaluations to land management across geographic boundaries and in areas undergoing land use change. Resource allocation and decision making at the national scale needs to be based on comparable metrics. We used a combination of qualitative and quantitative data to evaluate the potential for an integrated grazingland assessment approach based on common indicators. Comparisons of rangeland and pastureland assessment indicators suggested that there are significant relationships between many of the indicators in rangeland health and pasture condition scoring methods. However, there were differences, both in the indicators used and in assessments of seemingly common indicators. We suggest the need for a unified approach that captures the best from both the rangeland and pastureland assessment methods while taking into account ecosystem attributes and management objectives of the grazinglands where these methods are usually applied. The Interpreting Indicators for Rangeland Health protocol provides a way to assess and interpret soil and site stability, biotic integrity, and hydrologic function attributes based on ecological potential at a site. The Pasture Condition Scoring protocol provides a framework that could potentially be used to formalize management interpretations at a site based on ecological potential and based on management practices that could exceed the productive potential at a site. We propose that the strengths of the two protocols be integrated using a consistent framework to gather and interpret data, which will provide comparable metrics across all grazinglands.

}, doi = {10.2489/jswc.69.4.110A}, url = {files/bibliography/14-040.pdf}, author = {David P. Toledo and Matt A Sanderson and Jeffrey E. Herrick and Sarah Goslee} } @proceedings {JRN54540, title = {The impacts of grazing land management on the wind erodibility of the Mulga Lands of western Queensland, Australia}, volume = {p. 60}, year = {2012}, month = {09/2012}, publisher = {Australian Rangeland Society}, address = {Kununurra, Western Australia}, abstract = {An estimated 100 Mt of dust is eroded by wind from the Australian land surface each year. Wind erosion may be widespread across the arid and semi-arid rangelands, with impacts on soil nutrients, carbon and ecosystem services, human health, and climate. The susceptibility of landscapes to wind erosion (their erodibility) is highly sensitive to changes in vegetation cover and soil properties like crusting and aggregation, which control the area of bare ground exposed to erosive winds, and the availability of fine erodible sediment. Pastoralism, including the production of cattle and sheep, is thought to modify these controls through its impacts on vegetation cover and soil surface properties. However, research is yet to quantify the impact of grazing land management on the erodibility of rangelands, or how these impacts vary between land types. We present a simulation analysis that implements the Australian Land Erodibility Model (AUSLEM) in line with a pasture growth and animal production model (GRASP) to evaluate the impacts of grazing management on the erodibility of 5 land types in western Queensland. The study has tested separately the effects of stocking rates, stocking strategies and land condition on wind erodibility. Our results show that wind erodibility increases with stocking rate, showing a nonlinear response that varies in intensity between land types. Susceptibility of the land types to wind erosion is shown to increase under stocking strategies that lack flexibility or the capacity to rapidly destock in response to drought conditions. However, moving from high stocking rates under a fixed stocking to a more flexible strategy is shown to have a greater effect on erodibility than differences between flexible stocking strategies based around the long term safe stocking rates. The degradation of land condition results in an increase of wind erodibility with an abrupt change of rates representing major shifts in environmental conditions. The analysis indicates that historical stocking rates have had a high impact on wind erodibility; however, under the current stocking rate, impacts on wind erodibility are reduced. Wind erodibility can be reduced by adopting a conservative management with low stocking rates as well as maintaining the land in good condition.}, keywords = {GRASP, land degradation, management, modelling, stocking rate, wind erosion}, author = {Aubault, Helene and Nicholas Webb and Scanlan, Joe C. and Craig Strong and John Leys} } @article {49882, title = {Increasing shrub use by livestock in a world with less grass}, journal = {Rangeland Ecology and Management}, volume = {65}, year = {2012}, month = {11/2012}, pages = {553-562}, chapter = {553}, abstract = {

Much of the world\&$\#$39;s rangelands are dominated by woody species. Competing land uses and continued encroachment of woody species into non-woody dominated rangelands have reduced grasslands in many parts of the world. Land use conversions to fuel and feed global populations, especially for increasing numbers of middle class people seeking broader, meat-based diets, will certainly continue. Halting and/or reversing further encroachment of woody species into grasslands is slow, expensive, and in some cases, not possible. Yet, global livestock numbers continue to increase to meet the growing demand for red meat and other livestock products. How do we reconcile a world with less grass and the concurrent increased demand for forages to feed livestock, either in extensive rangeland production systems or intensive confined feeding systems? Strategies and mechanisms are needed to safely enhance shrub use by ruminants in order to capitalize on a presently underutilized forage resource. Such strategies could provide important means for rural communities to adapt to changing land cover and climate.

}, keywords = {animal behavior, cattle, genetics, goats, plant secondary metabolites, sheep}, doi = {10.2111/REM-D-11-00124.1}, url = {/files/bibliography/12-031.pdf}, author = {Richard E. Estell and Kris Havstad and Andr{\'e}s F. Cibils and E.L. Fredrickson and D.M. Anderson and Scott T. Schrader and D. K. James} } @proceedings {JRN54551, title = {Intake of honey mesquite (Prosopis glandulosa) leaves by lambs using different levels of activated charcoal}, volume = {p. 29}, year = {2012}, month = {05/2012}, publisher = {Wildland Shrub Symposium}, address = {Las Cruces, NM}, abstract = {A 24-day feeding trial was conducted to assess the effect of feeding four levels of activated charcoal (0.0, 0.33, 0.67 and 1.00 g/kg of body weight) on intake of honey mesquite leaves (Prosopis glandulosa Torr.) by 20 wether lambs (36.6 {\textpm} 0.6 kg) that were randomly assigned to treatments. Lambs were fed low quality Sudan-grass hay at 2.0\% of body weight and 80 g of molasses during a 7 day adaption period followed by 16-day feeding trial where lambs were fed 1.9\% of body weight of same hay and 80 g of molasses mixed with assigned levels of charcoal. During the feeding trial, lambs had ad libitum access to honey mesquite leaves that had been previously harvested, frozen, and thawed immediately before feeding. No differences (P = 0.52) in day-to-day intake of mesquite leaves were detected among treatments. However, lambs consumed more mesquite leaves as the feeding trial progressed (P < 0.001). Mean intake of mesquite leaves were 20.7 {\textpm} 3.7, 23.8 {\textpm} 3.8, 20.2 {\textpm} 3.7, and 27.3 {\textpm} 3.7 g/day for the 0.0, 0.33, 0.67 and 1.0 levels of charcoal, respectively. During the last 8 days of the study, consumption of mesquite leaves varied greatly among lambs, ranging from 1.4 to 7.4\% of their diet. No differences were detected in hay intake (P = 0.23) and lamb weight gain (P = 0.58) among treatments. Future studies examining consumption of honey mesquite leaves by sheep should consider potential variation in intake among individual animals.}, author = {Piedad Mayagoitia and C. Donovan Bailey and Richard E. Estell} } @mastersthesis {49896, title = {Impermanence factors and rangeland management in the desert southwest}, volume = {MS}, year = {2012}, month = {August 2012}, pages = {144}, school = {New Mexico State University}, address = {Las Cruces}, abstract = {Impermanence syndrome has been defined as a condition of anticipation or even apprehension by farmers due to their perception of increasing urbanization pressures on cropland. This condition has been found to account for disinvestment as well as an erosion of producer confidence and long-run planning. This research attempts to determine the degree to which impermanence factors are perceived by western rangeland livestock producers operating on federal lands in the southwestern United States. Factors other than urbanization are explored as potentially contributing to impermanence perceptions and conditions.

Results from a survey of southwestern New Mexico ranch operators in six counties located in the U.S. Bureau of Land Management Las Cruces District were analyzed in order to identify ranch planning and management impacts related to proximity to the U.S.-Mexico border, multiple-use issues, public perception, as well as economic and regulatory issues. This thesis will present results of the survey and data analysis, discuss ranch management and planning implications, and explore policy implications of impermanence issues on public rangelands.}, keywords = {cropland, farming, impermanence syndrome, public rangeland, rangeland management, urbanization}, author = {Parry, Samuel Flake} } @proceedings {JRN54539, title = {Identifying thresholds in pattern-process relationships: a new cross-scale interactions experiment at the Jornada Basin LTER}, volume = {p. 43}, year = {2012}, month = {09/2012}, publisher = { LTER All Scientists Meeting}, address = {Estes Park, Colorado}, abstract = {Interactions among ecological patterns and processes at multiple scales play a significant role in threshold behaviors in arid systems. Black grama grasslands and mesquite shrublands are hypothesized to operate under unique sets of feedbacks: grasslands are maintained by fine-scale biotic feedbacks promoting the retention of plant-available water that promotes grass establishment and persistence, while shrublands are maintained by broader-scale abiotic feedbacks promoting an increase in bare ground connectivity and redistribution of material by wind that promote shrub expansion. We recently established a large-scale, long-term manipulative experiment to test these hypotheses in order to identify the threshold distribution of bare gaps beyond which plant-scale processes are overwhelmed by abiotic drivers to shift grassland system into shrublands. In a 2 x 2 factorial design at 15 experimental blocks arrayed along an existing gradient of bare ground connectivity, we manipulated a plant-scale biotic process and a patch-scale abiotic process to measure the relative importance of these controls on primary production, soil water dynamics, and other ecological responses. All mesquite shrubs were killed to manipulate plant-scale competition for resources. We installed small fence-like structures (connectivity modifiers, or ConMods) to manipulate bare ground connectivity of surface soil and plant material by wind at a patch scale. This experiment will improve understanding of the role of cross-scale interactions that lead to threshold dynamics across mixed lifeform ecotones.}, author = {Pillsbury, Finn C. and Debra C. Peters and Gregory S. Okin and Danielle Duni and John P. Anderson and O. E. Sala and Enrique Vivoni and Jeffrey E. Herrick and Kris Havstad} } @proceedings {JRN54541, title = {Implications of carbon dust emission for terrestrail carbon cycling and carbon accounting}, volume = {A33D-0184}, year = {2012}, month = {12/2012}, publisher = {American Geophysical Union}, address = {San Francisco, CA}, abstract = {Wind erosion preferentially removes the finest carbon- and nutrient-rich soil fractions, and consequently its role may be significant within terrestrial carbon (C) cycles. However, the impacts of wind erosion on soil organic carbon (SOC) redistribution are not considered in most carbon cycle models, or within national carbon accounting schemes. Current estimates of the loss of SOC to wind erosion do not consider the preferential removal and enrichment of SOC in dust emissions, and consequently underestimate the significance of carbon dust emissions for the carbon cycle and carbon accounting. We present a process-based approximation of SOC enrichment within the Computational Environmental Management System (CEMSYS v5) Australian national wind erosion model. It enabled the prediction of carbon dust emission at a 50 km spatial resolution across Australia each month from 2000{\textendash}2011. Our results show that the total dust emission for Australia is 118 Mt yr-1, with carbon dust emissions (<22 {\textmu}m) in the order of 1.59 Mt yr-1. Rangelands are found to produce ~84\% of Australia{\textquoteright}s carbon dust emissions (1.34 Mt yr-1), while agricultural lands produce 0.11 Mt yr-1. However, agricultural lands produce larger carbon dust emissions per km2 than rangelands. The long-distance transport of SOC by wind is expected to result in large mineralisation rates due to (e.g.) photochemical oxidation, and the release of up to 5.9 Mt CO2-e yr-1. These results on the loss of SOC in dust, and the release of CO2 during long-distance transport, demonstrate the need for aeolian processes to be given greater significance in terrestrial carbon cycling, and for them to be incorporated into carbon accounting systems.}, author = {Nicholas Webb and A. Chappell and Harry Butler and Craig Strong and Grant McTainish and John Leys} } @conference {49946, title = {Incorporating spatial patterns into a state and transition model for arid grasslands and shrublands in southern New Mexico}, booktitle = {96th Ecological Society of America Meeting}, year = {2011}, month = {08/2011}, publisher = {ESA}, organization = {ESA}, address = {Austin, Texas}, abstract = {State and transition models synthesize and communicate information about alternative states in arid rangelands and other ecosystems but often do not adequately account for processes interacting across a range of temporal and spatial scales. Grassland to shrubland transitions have occurred as patchy and asynchronous patterns in arid lands across the world and remain poorly understood beyond local-scale drivers and regional land use trends. A landscape perspective that acknowledges the role of heterogeneity in land history, soil-geomorphic patterns and processes, and other broad-scale interactions can be used to interpret and predict local state-transitions.\  We ask: what governs the abundance and distribution of alternative states and what spatially structured processes are related to transition mechanisms? A broad range of historical and contemporary data was used to produce a spatial state-and-transition model for a relict basin floor landscape on the Jornada Experimental Range in south-central New Mexico, USA.\  We quantified the spatial pattern of state transition from repeat aerial photography and historical land cover maps and identified temporal and spatial patterns and thresholds of grass production from historical field data, historical maps, and management records. We used repeated plot based soil-vegetation inventory spatially linked to mapped patterns of transition to identify past drivers and constraints defining current state functioning in grass-shrub-soil interactions. We present a spatially explicit state and transition model that addresses:\  (1) spatial variation in land use driver history which explains transition pattern differences in otherwise uniform areas, (2) spatial dependence in response to drivers filtered by soils, landform, and climate, and (3) contagious processes mediated by vegetation-environment feedbacks which propagate transitions beyond the point of initial impact in a predictable way. We illustrate how variation in soil development, land-use decisions in the early 20th century, and contagious processes related to shrub spread and erosion have shaped the pattern of transition in this landscape.\  We also note the implications of these patterns for management responses at different points in time and in different parts of the landscape.}, author = {D. Goolsby and Brandon T Bestelmeyer and Steven R. Archer} } @article {49958, title = {Image processing and classification procedures for analysis of sub-decimeter imagery acquired with an unmanned aircraft over arid rangelands}, journal = {GIScience \& Remote Sensing}, volume = {48}, year = {2011}, pages = {4-23}, chapter = {4-23}, abstract = {Unmanned aerial systems (UAS) have great potential as a platform for acquiring very high resolution aerial imagery for vegetation mapping. However, image processing and classification techniques require adaptation to images obtained with low-cost digital cameras. We developed and evaluated an image processing workflow that included the integration of resolution-appropriate field sampling, feature selection, and object-based image analysis for the purpose of classifying rangeland vegetation from a five-centimeter-resolution UAS image mosaic. Classification tree analysis was used to determine the optimal spectral, spatial, and contextual features. Segmentation and classification rule sets were developed on a test plot and were applied to the remaining study area, resulting in an overall classification accuracy of 78\% at the species level and 81\% at the structure-group level. The image processing approach provides a roadmap for deriving quality vegetation classification products from UAS imagery with very high spatial, but low spectral resolution.}, doi = {10.2747/1548-1603.48.1.4}, url = {/files/bibliography/11-001.pdf}, author = {Andrea S. Laliberte and A. Rango} } @article {49968, title = {Impacts of atmospheric nutrient deposition on marine productivity: Roles of nitrogen, phosphorus, and iron}, journal = {Global Biogeochemical Cycles}, volume = {25}, year = {2011}, pages = {GB2022}, keywords = {atmospheric deposition, iron, marine productivity, nitrogen, nutrient deposition, phosphorus}, author = {Gregory S. Okin and Baker, A. R. and Tegen, I. and Mahowald, N. M. and Dentener, F. J. and Duce, R. A. and Galloway, J. N. and Hunter, K. A. and Kanakidou, M. and Kubilay, N. and Prospero, J. M. and Sarin, M. M. and Surapipith, V. and Uematsu, M. and Zhuo, T.} } @article {49992, title = {Image interpreter tool: An ArcGIS tool for estimating vegetation cover from high-resolution imagery}, journal = {Rangelands}, volume = {33}, year = {2011}, month = {08/2011}, pages = {35-40}, chapter = {35}, abstract = {Land managers need increased temporal and spatial resolution of rangeland assessment and monitoring data. However, with flat or declining land management and monitoring agency budgets, such increases in sampling intensity are unlikely unless new methods can be developed that capture data of key rangeland indicators at a lower cost. Remote sensing techniques have shown promise for collecting plant community composition and ground cover data efficiently. However, many image analysis techniques require software and expertise not always available to field offices. This article describes Image Interpreter Tool (IIT): a series of ArcGIS 9.3 tools and workflow procedures that have been developed to meet this need. The tool and procedures were designed to streamline: 1) the calibration of image interpretation users, and 2) the collection of vegetation and ground-cover types for a study site or project. IIT is distributed as a customized ArcMap document or template with nothing to install, and is compact enough to be used on portable storage devices such as USB thumb drives. IIT can be used by people with little or no GIS experience and reduces recording errors by providing an automated system for attributing data files. IIT mimics point-intercept field-sampling methods using remotely sensed data, \“virtual\” points along transects, and a simple and intuitive interface-to-estimate cover. Three main cover categories are used: noncanopy (rock, litter, soil, and lichens), herbaceous cover (grass and forbs), and woody canopy (subshrub, shrub, tree, and succulent). Additionally, users can toggle between true color and color-infrared versions of the imagery (assuming four-band imagery is used as a source) with a simple click of a button on the interface. IIT is easy to learn and is designed to facilitate multiple users producing consistent results. IIT is divided into two modules: 1) an observer training and calibration module that includes quality assurance and quality control procedures, and 2) a data collection module.}, doi = {doi: 10.2111/1551-501X-33.4.35}, url = {/files/bibliography/11-028.pdf}, author = {Scott T. Schrader and Danielle Duni} } @mastersthesis {49997, title = {Insights on seasonal fluxes in a desert shrubland watershed from a distributed sensor network}, year = {2011}, pages = {171}, school = {Arizona State University}, type = {Masters}, abstract = {

\ \ \ \  The North American Monsoon System (NAMS) contributes ~55\% of the annual rainfall in the Chihuahuan Desert during the summer months. Relatively frequent, intense storms during the NAMS increase soil moisture, reduce surface temperature and lead to runoff in ephemeral channels. Quantifying these processes, however, is difficult due to the sparse nature of coordinated observations.
\ \ \ \  In this study, I present results from a field network of rain gauges (n = 5), soil probes (n = 48), channel flumes (n = 4), and meteorological equipment in a small desert shrubland watershed (~0.05 km2) in the Jornada Experimental. Using this high-resolution network, I characterize the temporal and spatial variability of rainfall, soil conditions and channel runoff within the watershed from June 2010 to September 2011, covering two NAMS periods. In addition, CO2, water and energy measurements at an eddy covariance tower quantify seasonal, monthly and event-scale changes in land-atmosphere states and fluxes.
\ \ \ \  Results from this study indicate a strong seasonality in water and energy fluxes, with a reduction in Bowen ratio (B, the ratio of sensible to latent heat fluxes) from winter (B = 14) to summer (B = 3.3). This reduction is tied to shallow soil moisture availability during the summer (s = 0.040 m3/m3) as compared to the winter (s = 0.004 m3/m3). During the NAMS, I analyzed four consecutive rainfall-runoff events to quantify the soil moisture and channel flow responses and how water availability impacted the land-atmosphere fluxes. Spatial hydrologic variations during events occur over distances as short as ~15 m.
\ \ \ \  The field network also allowed comparisons of several approaches to estimate evapotranspiration (ET). I found a more accurate ET estimate (a reduction of mean absolute error by 38\%) when using distributed soil moisture data, as compared to a standard water balance approach based on the tower site. In addition, use of spatially-varied soil moisture data yielded a more reasonable relationship between ET and soil moisture, an important parameterization in many hydrologic models. The analyses illustrates the value of high-resolution sampling for quantifying seasonal fluxes in desert shrublands and their improvements in closing the water balance in small watersheds.

}, keywords = {carbon dioxide flux, Chihuahuan Desert, CO2 flux, eddy covariance, evapotranspiration, hydrology, NAMS, North American Monsoon System, rainfall, runoff, soil moisture, soil temperature, Tromble Weir Watershed}, url = {files/bibliography/JRN00569.pdf}, author = {Ryan Templeton} } @article {50001, title = {Impact of stocking rate and rainfall on sheep performance in a desert steppe}, journal = {Rangeland Ecology \& Management}, volume = {64}, year = {2011}, month = {07/2011}, pages = {249-256}, chapter = {249}, abstract = {Livestock performance is a critical indicator of grassland production systems and is influenced strongly by precipitation and stocking rates. However, these relationships require further investigation in the arid Desert Steppe region of northeastern China. We employed a randomized complete block design with three replications and four grazing treatments (nongrazed exclosure [Control]), lightly grazed [LG], moderately grazed [MG], and heavily grazed [HG]) by sheep in a continuously grazed system (June to November), to test the effect of stocking rate on sheep performance. The planned stocking rates were 0, 0.15, 0.30, and 0.45 sheep-ha-1 mo-1, for the control, LG, MG, and HG treatments, respectively. However, actual stocking rates were calculated for each paddock in each year based on a 50-kg sheep equivalent (SE). Annual net primary production (ANPP) was determined at peak standing crop in August 2004 to 2008. Live weight gain was determined for the summer and fall periods, as well as the total grazing period, in each year. ANPP decreased with increasing stocking rate, and daily live weight gain per head decreased linearly with increasing stocking rates over the total grazing period but in a quadratic manner over the summer period with a plateau at the lower rates. Maximum sheep production per unit area over the total grazing season occurred at about 2 SE ha-1 for about a 5-mo grazing period, but individual gains per sheep were predicted to decline after about 1 SE ha-1 presumably because of forage limitations. However, in order to achieve stable annual production, we recommend that the Desert Steppe be grazed at about 0.77 SE ha-1 for a 5-mo period (0.15 SE ha -1 mo-1). This estimate is based on published grazing strategies that consider an average ANPP with a recommended utilization rate of 30\%.}, keywords = {grazing management, Inner Mongolia, live weight gain, optimal stock rate, Stipa breviflora Griseb}, doi = {10.2111/rem-d-09-00033.1}, url = {/files/bibliography/11-012.pdf}, author = {Zhongwu Wang and Jiao, Shuying and G. Han and Mengli Zhao and Walter Willms and Hao, Xiying and Jian{\textquoteright}an Wang and Din, Haijun and Kris Havstad} } @article {50014, title = {An introduction to the special issue on ecological sites}, journal = {Rangeland}, volume = {32}, year = {2010}, month = {12/2010}, pages = {3-4}, chapter = {2}, abstract = {

The establishment of the Rangeland Interagency Ecological Site Manual by the Natural Resources Conservation Service (NRCS), Forest Service (FS), and the Bureau of Land Management (BLM) heralds a new era of rangeland management in the United States (http://www.fs.fed.us/biology/soil/Signed_RIESM_2010.pdf). The manual promises to establish a land stratification system and approaches for describing ecosystem structures, functions, and dynamics in the form of ecological site descriptions, such that they can be applied to all rangelands, no matter their jurisdiction or ownership. The common basis for decision-making will lead to improved coordination and more consistent, transparent, and useful application of science concepts in rangeland management. NRCS has had primary responsibility for the development of ecological site descriptions in the past. This responsibility will be now be shared by all three agencies. At this juncture, we summarize in this special issue the state of the art in the development of ecological site descriptions, recognizing that this art will evolve over the coming decades.

}, url = {/files/bibliography/10-041.pdf}, author = {Brandon T Bestelmeyer and Joel R. Brown} } @conference {JRN54494, title = {In search of "Organ III" strata-a sedimentary record of the Medieval Warm Period (ca. AD 900 to 1300)}, booktitle = {16th Biennial Mogollon Archeology Conference}, year = {2010}, month = {10/2010}, publisher = {16th Biennial Mogollon Archeology Conference}, organization = {16th Biennial Mogollon Archeology Conference}, address = {Las Cruces, NM}, abstract = {The period AD 900 to 1300, internationally referred to as the Medieval Warm Period, is a critical time for the archaeological record of the Southwestern USA. During the Medieval Warm Period both alluvial and eolian sedimentation increased, but not to the magnitude of the middle Holocene (the Altithermal) or since Historical erosion began in the middle 1850s (the end of the Little Ice Age). Locally, the term {\textquotedblleft}Organ III{\textquotedblright} has been given to the Medieval Warm Period allostratigraphic unit. It is a subtle unit stratigraphically between Altithermal sediments (Organ I) and Historical sediments. Diagnostic features for identifying these three units include the following: Organ I has distinct carbonate filaments and strong pedogenic structure; Organ III has very faint carbonate filaments and weak pedogenic structure; Historical deposits have no carbonate and sedimentary layers. The Organ III stratum is most obvious in geomorphic settings with contrasting parent materials or where an occupational surface underlies the Organ III unit. In addition to its archaeological significance, the Organ III unit provides information about the relative magnitude of current climate change as compared to prehistoric climate change.}, author = {Curtis H. Monger and Laney, Katie and E.L. Fredrickson} } @article {50057, title = {Impact of flight regulations on effective use of unmanned aerial vehicles for natural resources applications}, journal = {Journal of Applied Remote Sensing}, volume = {4}, year = {2010}, pages = {043539}, abstract = {Unmanned Aerial Vehicles (UAVs) have great potential for rangeland assessment, monitoring, and management as has been shown by prior studies. Additionally, numerous other applications in natural resources have shown the value of using UAVs. In order to have UAVs become a dependable tool for public land management agencies in carrying out their government-mandated responsibilities, it is necessary to integrate UAVs into the National Airspace System (NAS). To achieve this, Federal Aviation Administration (FAA) regulations have to be followed to assure public safety. UAV operators need to know that the safety regulations which incorporate line of sight restrictions will slow progress towards an operational system and plan accordingly for the extra time necessary to prepare and complete flight missions. In the long term by following approved safety procedures, you will develop a UAV flight team that is capable of accomplishing missions anywhere in the United States and contribute to a totally integrated NAS comprised of manned and unmanned aircraft systems that can be used jointly for natural resources management. At the same time, it is hoped that FAA regulations will change with time based on the locale in which operations take place, especially when they include large, remote, sparsely populated areas, and based on the capabilities and experience of the UAV flight team being used.}, keywords = {aerial photography, civilian applications, FAA regulations, National Airspace System, rangeland management, Small unmanned aerial vehicles}, url = {/files/bibliography/10-021.pdf}, author = {A. Rango and Andrea S. Laliberte} } @conference {JRN54478, title = {Infrastructure improvements for snowmelt runoff assessments of climate change impacts on water supplies in the Rio Grande basin}, booktitle = {Western Snow Conference, 2010}, year = {2010}, month = {04/2010}, address = {Logan, Utah}, abstract = {

It has become apparent that the effects of climate change will be especially important for Southwestern US water users. The NSF-funded EPSCoR project {\textquotedblleft}Climate Change Impacts on New Mexico{\textquoteright}s Mountain Sources of Water{\textquotedblright} focuses on improving hydrometeorological measurements, developing basin-wide and sub-basin snow cover mapping methods, generating snowmelt runoff simulations and long-term climate change assessments, and informing the public of the results through outreach and educational activities. Five new and 12 upgraded SNOTEL sites, four SCAN stations and about 30 new automated weather stations are being added to New Mexico measurement networks. 25 sub-basins of the Rio Grande have been identified as important snowmelt basins where development and testing of snow cover mapping methods will be conducted. High spatial resolution Landsat TM data (30 m) are being used to evaluate estimates of snow cover from Terra MODIS moderate spatial resolution data (250m and 500 m). We aim to identify the best snow-mapping algorithm for the Rio Grande basin using Snowmelt Runoff Model (SRM) simulations. For the snowmelt modeling, we are using an updated revision of SRM which can automatically assess the climate change effects on water supplies of future climate scenarios.

}, author = {A. Rango and Caitriana Steele and Demouche, Leann} } @article {50060, title = {An improved protocol for micropropagation of saltbush (atriplex) species}, journal = {Native Plant Journal}, volume = {11}, year = {2010}, pages = {53-56}, abstract = { Atriplex griffithsii Standl is a threatened halophytic shrub found in saline soils of isolated regions within the desert basins in Southern New Mexico and Arizona. A related species within the genus, A. canescens, has been successfully micropropagated, suggesting that clonal propagation may offer a strategy to produce large numbers of A. griffithsii plants for conservation, restoration, or research needs. However, previously reported A. canescens micropropagation protocols could not be reproduced with A. griffithsii. Here we evaluated rates of shoot production of A. griffithsii explants exposed to varied growth regulator treatments. Maximal shoot productivity was observed with explants exposed to 1.14 \µM indole 3-acetic acid (IAA) + 24.61 \µM 6-(\&$\#$39;-\&$\#$39;-dimethylallylamino) purine (2iP). Rooting frequencies of 55\% were observed on hormone free medium. Results demonstrate potential to micropropagate clonal A. griffithsii, a species with potential for restoration of saline soils.}, url = {/files/bibliography/10-013.pdf}, author = {I. Reyes-Vera and M.E. Lucero and J.R. Barrow} } @conference {JRN54591, title = {Impact of disturbance on soil microbial activity in the Northern Chihuahuan Desert}, booktitle = {13th International Symposium on Microbial Ecology}, year = {2010}, month = {08/2010}, publisher = {International Symposium on Microbial Ecology}, organization = {International Symposium on Microbial Ecology}, abstract = {Cryptobiotic soil crusts in arid regions contribute to ecosystem stability through increased water infiltration, soil aggregate stability, and nutrient cycling between the soil community and vascular plants. These crusts are particularly sensitive to compaction/fracturing disturbances such as livestock grazing, off-road vehicle use, trampling by humans, and drilling and mining activities. Loss of soil crusts is believed to increase the rate of desertification, and recent findings indicate that crusts are extremely slow to recover, on the order of hundreds of years. However, post-disturbance recovery rates for soil bacterial and fungal populations is vastly understudied, and it is suggested that loss of soil crusts leads to decreased abundance and diversity of these non-crust soil biota. Soil microbial activity within and around two natural gas well pads embedded within a livestock grazing area were investigated. During the natural gas extraction process, the shallow surface soil is stockpiled near the well pad. Surface and subsurface soil samples were taken from the heavily compacted well pad, the surface soil stockpile (fallow 12 yr), the grazed area outside of the well pad, and a lightly grazed area with intact crusts. Microbial activity was measured using the MicroResp{\texttrademark} 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). Preliminary results indicate slightly reduced activity in heavily disturbed well pad areas compared to grazed areas, although overall activity for all samples was not significantly different from controls. Activity was marginally higher in surface soils (top 5 cm) compared to subsurface soils (5-30 cm).}, author = {Schwab, Lori K. and Unc, Adrian and M.E. Lucero} } @conference {JRN54484, title = {Impact of pilling and long-term topsoil storage on the potential soil microbial activity in the Northern Chihuahuan Desert}, booktitle = {Argonomy Society os America, Crop Science Society of Americas, and Soil Science of America Meeting}, year = {2010}, month = {11/2010}, address = {Long Beach, CA}, abstract = {Cryptobiotic soil crusts in arid regions contribute to ecosystem stability through increased water infiltration, soil aggregate stability, and nutrient cycling between the soil community and vascular plants. Natural gas mining involves removal of the topsoil, including surface crust, and storage of the removed topsoil in piles at the edge of the operation. Often this topsoil is stored for extended periods ranging from a few years to decades. During removal and piling the soil layers are often mixed and reversed. During storage the soil-pile surface is rarely vegetated. Currently we have no understanding of the significance of these practices on the microbiological metabolic potential of these soils. Since little vegetation is able to reestablish on the piles during extensive storage periods it is generally assumed that the soil{\textquoteright}s biologic potential degrades. Soil microbial activity within such storage piles around a natural gas well pad in the Northern Chihuahuan desert was investigated. Surface and subsurface soil samples were taken from different layers of the topsoil stockpile (fallow 12yr). Microbial activity was measured using the MicroResp{\texttrademark} 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).~Heterotrophic microbial growth was evaluated by plating soil subsamples on agars aimed at recovering copiotrophes and oligotrophes. Genetic diversity of the recovered and directly extracted DNA was evaluated via 16S PCR-DGGE targeting the V3 and V6 variable regions. Preliminary results indicate that, interestingly, the greatest microbial activity was measured in the soil stockpile at a depth of 5-30cm.}, author = {Schwab, Lori K. and Unc, Adrian and M.E. Lucero} } @conference {50061, title = {Indicators of Range Health}, booktitle = {Society for Range Management}, year = {2010}, address = {Denver, CO}, abstract = {Science-based grassland management requires an understanding of the current status of the land relative to its potential. Rangeland health assessments help increase the cost-effectiveness of management by identifying where a change in management may be required, and the types of ecological processes that need to be addressed. We will discuss a suite of 17 indicators that are used throughout the United States to assess three attributes of rangeland health: soil and site stability, hydrologic function and biotic integrity. A unique reference for assessment is developed for each type of soil and climate. These references are based on both scientific knowledge and local knowledge. We will also discuss how this indicator-based assessment system can be used together with other tools, including state and transition models, and monitoring, to improve management.}, keywords = {management, rangeland health}, author = {P. L. Shaver and Jeffrey E. Herrick} } @inbook {50077, title = {Integrating terrestrail sequestration into a greenhouse gas management plan}, booktitle = {Carbon Sequestration and Its Role in the Global Carbon Cycle}, series = {Geophysical Monograph Series 183}, year = {2009}, pages = {317-324}, publisher = {American Geophysical Untion}, organization = {American Geophysical Untion}, address = {Washington, DC}, abstract = {Terrestrial sequestration is the deliberate process of storing carbon in the soil or vegetation via the net effect of naturally occurring processes (photosynthesis, leading to storage in plants; humification and aggregation, leading to conversion of plant carbon to soil carbon; and respiration, which returns some plant and soil carbon to the atmosphere as CO2). Removing carbon from the atmosphere via terrestrial sequestration has been proposed as a critical element in the portfolio of actions to stabilize greenhouse gases in the atmosphere and avoiding undesirable climate change. One benchmark for integrating terrestrial sequestration into a GHG management plan might be to increase sequestration beyond {\textquotedblleft}business-as-usual{\textquotedblright} levels by an average of about 1-2 PgC/yr during the next 50 years. Assuming this benchmark is accomplished by a linear increase in sequestration rates, the integrated total over 50 years would be 25-50 PgC. Achieving this level of performance will require 1) improvements in existing understanding of sequestering processes, 2) more focused incentive programs to accelerate adoption and maintenance of sequestering practices and 3) an enhanced monitoring and verification effort to insure credibility.}, keywords = {carbon, proceedings, sequestration, terrestrail}, url = {/files/bibliography/09-030.pdf}, author = {Joel R. Brown and Sampson, N.}, editor = {McPherson, Brian J. and Sundquist, Eric T.} } @conference {50086, title = {Influence of weather and animal related factors on grazing distribution of livestock}, booktitle = {62nd Society for Range Mangement Annual Meeting}, year = {2009}, month = {02/2009}, pages = {03-12}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Albuquerque, NM}, abstract = {

Automated monitoring of animal locations at relatively short time intervals has allowed new insights into how biotic and abiotic factors influence spatial distribution patterns of livestock. We will discuss recently completed and on-going grazing behavior studies using GPS/GIS approaches at sites in New Mexico (USA) and Argentina. These studies seek to determine the influence of weather and animal-related factors (reproductive state and stress coping style) on spatial distribution patterns of cattle and sheep at the scale of days and plant communities. Data from our New Mexico site showed that: a) ambient temperature, relative humidity, wind direction, and short term thermal stress, were significant predictors of day-to-day plant community preference patterns of young cows; b) foraging decisions appeared to be influenced by ambient temperatures that were well within an cow\&$\#$39;s thermoneutral zone; c) animal physiological state (nursing vs. open non-nursing) had small and transient effects on day-to-day changes in plant community preference of cows; d) young calves appeared to impose very few constraints on their dams\&$\#$39; movement patterns; and e) groups of cows classified on the basis of stress coping styles (nervous vs. calm) exhibited different spatial use patterns. On-going research at three sites situated along a latitudinal environmental gradient in Argentina (from hot sub-humid to cold semi-desert) using similar GPS/GIS approaches to those currently being used in NM will also be discussed. NM-Argentina cross-site comparisons are expected to advance current understanding of the foraging decision process of rangeland-raised livestock.

}, keywords = {abstract, animal, GIS, GPS, grazing, monitoring, SRM}, author = {Andr{\'e}s F. Cibils and Rubio, C.M. and Wesley, R.L. and M.K. Petersen and E.L. Fredrickson and M. A. Brizuela and Cid, M.S.} } @conference {50090, title = {Impacts of a road network on a semiarid grassland}, booktitle = {Ecological Society of American Abstracts}, year = {2009}, month = {08/2009}, pages = {PS 82-81}, abstract = {

An unprecedented amount of road, trail, and other infrastructure development is currently occurring or planned for many arid and semiarid ecosystems nationally. This is due to a variety of factors, including energy resources development (oil, gas, wind, solar, coaled methane, and others), recreational off-road vehicle activity, exurban development and military training. Planning and mitigation necessary to protect these ecosystems require accurate identification of highest resilience areas, including those most resistant to degradation and those that have the greatest capacity to recover quickly following degradation. The objective of this study was to develop a strategy for assessing the long-term effects of different types of roads on adjacent soil and vegetation properties in a southern New Mexico grassland. To accomplish this objective, 110 plots selected within a 63,418 acres study area using a stratified random sampling scheme. Plots were stratified by soil type (5 levels) and road type (3 levels: no road, major road and minor road). Additionally, to maximize detection of problem areas, we further stratified our base set of road points based on apparent impact as determined by qualitative aerial photo interpretation. Vegetation cover, soil cover, and soil aggregate stability data were collected along three 25-m transects at each plot. Overall, roads had significant, negative impacts on adjacent soils and vegetation when compared to non-road areas. The severity of impacts varied with soil type suggesting that road and trail development should be carefully planned to avoid more sensitive soils. Results indicate that most negative impacts due to road and trail development in the study area occurred in map units dominated by fairly coarse, low water holding capacity soils. Differences were primarily driven by reduced plant productivity in road corridors as indicated by increased bare ground and decreased canopy cover. In some soil types, loss of soil stability in unprotected locations also appears to be an issue. Few significant differences in plant community composition were detected between road and non-road areas. The level of road development did not consistently affect results, suggesting that concentration of activity along a smaller set of major roads may be one strategy to reduce cumulative impacts. For some soil types, the qualitative stratification technique was important for detecting rare but important negative impacts. This study illustrates the importance of integrated soil and ecological inventory data for incorporating site specific resilience knowledge into planning processes.

}, keywords = {coaled methane, ecosystem, energy resources, gas, military, off-road vehicle, oil, recreational, road, solar, trail, wind}, author = {Danielle Duni and Jeffrey E. Herrick} } @conference {50109, title = {Importance of ecotone type to landscape dynamics at biome transition zones}, booktitle = {US International Association for Landscape Ecology}, year = {2009}, note = {ProCite field[3]: May 26, 2009ProCite field[28]: November 1, 2008ProCite field[29]: January 28, 2009ProCite field[35]: Abstract}, abstract = {Landscapes in biome transition zones consist of a mosaic of patches dominated or codominated by species from adjacent biomes. Shifts in the vegetation composition and dynamics of a biome transition zone depend upon the underlying patch dynamics of the ecotones between these dominant species. Landscapes can consist of a number of different types of ecotones (directional, shifting, stationary) hypothesized to differ in the strength of three major factors: abiotic drivers, biotic feedbacks, and abiotic feedbacks. In this poster, our objective was to test the hypothesis that vegetation patterns across stationary ecotones are strongly related to abiotic factors that influence water availability (soil texture, microtopography) where weak correlations were expected for shifting ecotones. We tested this hypothesis for landscapes at the Sevilleta LTER site in central New Mexico, USA. Landscapes at the Sevilleta consist of a mosaic of patches dominated or codominated by three species: two perennial C4 grasses, Bouteloua gracilis (blue grama) and Bouteloua eriopoda (black grama), and one C3 shrub, Larrea tridentata (creosotebush). We estimated cover by species, analyzed soil samples (0-20 cm), and obtained elevation using a Total Positioning Station every 5-10 m along multiple transects for 10 ecotones. Our results show that stationary ecotones occur on finer-textured soils at slightly lower elevations (cms) compared with shifting ecotones. Soil and elevation were not good predictors of the location of shifting ecotones. Our results suggest that landscape dynamics at the biome transition zone depend on the factors controlling different types of ecotones. Even though the same species may be involved, the underlying processes determining ecotones dynamics may vary for different parts of the landscape.}, keywords = {biome transition zones, Bouteloua gracilis, Boutelous eriopoda, Chihuahuan Desert grasslands, Grass-shrub interactions}, author = {Jeremy R. Klass and Debra C. Peters} } @conference {50132, title = {Indicators of regime shifts in long-term ecological data}, booktitle = {Ecological Society of America Annual Meeting}, year = {2009}, month = {August 2-9, 2009}, pages = {OOS 9-3}, abstract = {Long-term ecological data provide opportunities to examine and compare ecosystem-specific indicators of regime shifts. Our objective was to compare regime shifts from a number of different ecosystem types to determine similarities and differences in indicators. We used long-term data (> 10 years) in the EcoTrends project (http://www.ecotrends.info) from the US Long Term Ecological Research network of sites and from other state and federal agencies in this comparative analysis. Data included both plants and animals from terrestrial, aquatic, marine, and polar systems. In general, similar dynamics were observed across all systems in that abrupt increases in one system component were concurrent with abrupt decreases in another component. Length of time for the regime shift to occur varied across systems. In many cases, interactions among abiotic and biotic processes were important in driving these dynamics, and feedback mechanisms were important in maintaining the new regimes. In some cases, climatic drivers pushed a system past a threshold that provided opportunities for a regime shift, either by a shift in species dominance or by the successful invasion of a new species. This retrospective analysis can be used as a critical step in identifying key processes and conditions for which regime shifts occurred in the past, and to determine the potential for regime shift reversals. However, future analyses of indicators will also need to account for changing climatic conditions and other drivers, including invasive species, which were not part of the historic regime shifts.}, keywords = {ecological data, long-term, regime}, author = {Debra C. Peters} } @conference {JRN54477, title = {Infrastructure improvements for snowmelt runoff forecasting and assessments of climate change impacts on water supplies in the Rio Grande Basin}, booktitle = {American Geophysical Union}, year = {2009}, month = {12/2009}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {San Francisco, CA}, abstract = {In the Southwest US, the southern Rocky Mountains provide a significant orographic barrier to prevailing moisture-laden Westerly winds, which results in snow accumulation and melt, both vitally important to the region{\textquoteright}s water resources. The inherent variability of meteorological conditions in the Southwest, during both snowpack buildup and depletion, requires improved spatially-distributed data. The population of ground-based networks (SNOTEL, SCAN, and weather stations) is sparse and does not satisfactorily represent the variability of snow accumulation and melt. Remote sensing can be used to supplement data from ground networks, but the most frequently available remotely sensed product with the highest temporal and spatial resolution, namely snow cover, only provides areal data and not snow volume. Fortunately, the Snowmelt Runoff Model(SRM), which was developed in mountainous regions of the world, including the Rio Grande basin, accepts snow covered area as one of its major input variables along with temperature and precipitation. With the growing awareness of atmospheric warming and the southerly location of Southwest watersheds, it has become apparent that the effects of climate change will be especially important for Southwestern water users. The NSF-funded EPSCoR project {\textquotedblleft}Climate Change Impacts on New Mexico{\textquoteright}s Mountain Sources of Water{\textquotedblright} (started in 2009) has focused on improving hydrometeorological measurements, developing basin-wide and sub-basin snow cover mapping methods, generating snowmelt runoff simulations, forecasts, and long-term climate change assessments, and informing the public of the results through outreach and educational activities. Five new SNOTEL and four new SCAN sites are being installed in 2009-2010 and 12 existing basic SNOTEL sites are being upgraded. In addition, 30 automated precipitation gages are being added to New Mexico measurement networks. The first phase of snow mapping and modeling has focused on four sub basins, namely, the Rio Grande near Del Norte, CO and the Rio Hondo, Rio Chama, and Castillo Creek in NM, all tributaries of the Rio Grande basin. An additional 21 sub basins will be added as the development and testing of methods progresses. High spatial resolution Landsat TM data (30 m) are being used to evaluate estimates of snow cover maps from moderate spatial resolution data from Terra MODIS (250m and 500 m). Currently MODIS provides optimal temporal sampling (daily data) but the most effective MODIS-based snow cover mapping method has yet to be determined. We aim to identify the best MODIS snow-mapping algorithm for the Rio Grande area. For the snowmelt modeling, we are using an updated revision of SRM which directly accepts remote sensing snow cover inputs but can also automatically assess the climate change effects of future scenarios. The methods under development are intended for operational use by interested water resources agencies. With this end in mind, we will be developing an ArcGIS Toolbox (ESRI) and manual that will incorporate all the tools and instructions necessary for data download, re-projection and formatting, modeling and streamflow estimation.}, author = {A. Rango and Caitriana Steele and Demouche, Leann} } @conference {50141, title = {Impact of oil and gas infrastrucure development in La Manga Canyon, NM}, booktitle = {62nd Society for Range Management Annual Meeting}, year = {2009}, month = {02/2009}, pages = {2050-11}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Alb., NM}, abstract = {

La Manga Canyon is a small watershed (~20km2) in the San Juan Basin that has historically been developed for natural gas and recently for coal bed methane. Since gas production began in the 1940s, an extensive network of dirt roads have transected the watershed, providing access to well sites. There are currently eleven and a half wells per square mile with sometimes multiple wells in each well-pad. Land degradation due to energy extraction and historic livestock grazing make this area a good model for similar Great Basin landscapes, particularly in the understanding of soil and vegetation dynamics in high impact areas. Remote sensing was conducted from aerial photography taken in 1955, 1981, 1997, 2005 and 2006 to verify historic extent of well-pads, roads, and pipelines. Well-pads were digitized manually and roads / pipelines were remotely sensed with a supervised classification. Temporal vegetation change in the watershed was assessed at the ecological site level. Organic carbon was also estimated from soil cores (top 10cm) collected from roads, well-pads, and \“undisturbed\” vegetated areas within each ecological site. Linear disturbances increased from 100 to 250 ha between 1955 and 2006; total well-pad area increased from 12 to 72 ha over the same period. Roadless volume decreased by almost 50\%. Tree cover (primarily pinyon-juniper) increased along north facing slopes and decreased on south, west and east slopes. Herbaceous vegetation shifted to annual grasses. Vegetation dynamics in this watershed have been overwhelmed by energy infrastructure.

}, keywords = {gas, infrastructure, La Manga Canyon, NM, oil, SRM}, author = {S. W. Salley and Joel R. Brown} } @article {50144, title = {Indicator patches: exploiting spatial heterogeneity to improve monitoring systems}, journal = {Rangeland Journal}, volume = {31}, year = {2009}, month = {November 1, 2009}, pages = {385-394}, abstract = {When choosing which environmental attributes to monitor in assessing disturbance, it is important to consider not only which metric will provide the most sensitive indicator of disturbance, but also the spatial considerations of where in the landscape that metric will be most responsive to change. Degradation in landscapes is often unevenly expressed because: (i) disturbance is spatially localized, (ii) landscape elements differ in their sensitivity to disturbance, and (iii)degradation following localized disturbance is spatially contagious. The spatial heterogeneity of degradation has proven to be a key obstacle to rangeland monitoring (e.g. where the initiating processes of broad-scale degradation are concentrated in landscape locations that are not detected by surveys) but can also provide opportunities to focus monitoring efforts. We propose that the effectiveness of monitoring could be enhanced by identifying and selectively monitoring {\textquoteleft}indicator patches{\textquoteright}, i.e. specific landscape locations that provide the most management-relevant and timely information about the consequences of a monitored disturbance. We tested and demonstrated the utility of the {\textquoteleft}indicator patch{\textquoteright} concept in the rangelands of the Succulent Karoo in southern Africa. We contrasted the grazing response of dominant {\textquoteleft}representative{\textquoteright} vegetation, with responses of interspersed patches of distinct vegetation associated with zoogenic mounds. Since mound vegetation is more palatable and preferentially grazed by sheep, we tested whether mounds could serve as {\textquoteleft}indicator patches{\textquoteright} in providing a sensitive measure of grazing disturbance. Percentage canopy cover measurements in dominant offmound vegetation provided a poor indicator of grazing disturbance (although more intensive plant size measurements did reveal grazing impacts on plant population dynamics). In contrast, vegetation on mounds displayed patterns of changes in species abundances that were easier to detect and useful for interpreting and quantifying the effects of grazing. Mound vegetation could, therefore, be used as {\textquoteleft}indicator patches{\textquoteright} and targeted for exclusive sampling as a sensitive method for monitoring rangeland condition and detecting early warnings of vegetation change. This approach could be widely employed to better harness the extensive knowledge base regarding the patchy, spatially localized nature of degradation-initiating processes in numerous other landscapes. Routinely incorporating this understanding into the design of monitoring programs could improve the effectiveness of sampling effort, allow detection of more subtle trends (changes), and provide earlier warning of impending degradation so remedial action can be taken before degradation becomes severe and widespread.}, url = {/files/bibliography/09-027.pdf}, author = {C.J. Stokes and Yeaton, R.I. and Bayer, M.B. and Brandon T Bestelmeyer} } @article {50146, title = {Improving Field-Based Experimental Research to Compliment Contemporary Management}, journal = {Rangelands}, volume = {31}, number = {5}, year = {2009}, month = {09/2009}, pages = {26-30}, chapter = {26}, abstract = {

Rangeland management has long been described as both a science and an art (Stoddart et al. 1975). Certainly, the management of rangeland resources, especially during the last half of the 20th century, can be characterized as practices commonly informed by science. There are a number of management practices where synthesized bodies of experimentally derived observations have provided science-based rationales for their application and use. The collection of recorded observations from different field experiments in diverse environments has often resulted in reasoned understandings of relevant ecological processes and the structures and/or dynamics of these systems. At its core, rangeland management is a set of practices implemented over time that reflect a manager\’s understanding of the limits and opportunities of those structures and dynamics. A well-articulated body of scientific evidence can enhance understanding beyond generational knowledge or site specific experiences. Tension, though, between practitioners of science and art can result if synthesized knowledge is seen as either counter to or unsupportive of anecdotal knowledge or site based perceptions. At issue here is the reconciliation of scientific evidence with a perceived understanding accumulated from either personal or generational experiences, or accumulated over time at specific sites. For over 400 years Western Culture has been closely linked to science and scientific advances from medicine to physics to genetics to engineering to ecology. Yet, throughout this history we have seen science progress and provide its greatest contributions when it is understood within the general culture and eventually applied by the general population. Rangeland management may be more correctly viewed, then, as the artistic application of science-based principles. The role of science in rangeland management is not to try to evaluate each novel approach of the artist, but to continue to provide the principles that have application to the art. Science has provided basic principles for management tied to the spatial and temporal scales and uses of the 20th century land manager. The challenge for science today is to provide the principles for the spatial and temporal scales and the uses confronting the 21st century resource manager. We think that these science based principles will emerge from a combination of cross-scale, enterprise-level, interdisciplinary, and long-term type studies. But we have to conclude that the answer to the title of this paper is \"no\" \– traditional field research alone will not be sufficient, nor appropriate, to evaluate the majority of novel management approaches.\ http://www.srmjournals.org/

}, doi = {10.2111/1551-501X-31.5.26}, url = {/files/bibliography/09-029.pdf}, author = {Svejcar, Tony and Kris Havstad} } @conference {50154, title = {Inference space vs. sampling requirements: A simulation study of soil properties on rangeland ecosites}, booktitle = {62nd Society for Range Management Annual Meeting}, year = {2009}, month = {02/2009}, pages = {90-7}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Alb., NM}, abstract = {

Planning a monitoring project requires careful planning. The inference space of a project must be balanced with the sampling requirements. Inference space is the population from which the samples in a study were drawn and the population to which results of a study apply. Increasing the number of conditions in a project increases the inference space. Sampling requirements are the number of samples or measurements required to detect a given level of change. The number of samples required to detect change depends on the variability of the conditions being evaluated. In general, the fewer conditions that are sampled the lower the variability that will be observed and the lower the measurements required to detect change. Thus increasing the inference space is usually in direct conflict with reducing sampling requirements. This is a problem when available resources allow only a limited number of measurements. The objective of this study is to explore the balance between detectable change, inference space, and sampling requirements for a dataset of soil and range measurements. We use resampling procedures to show these relationships for a dataset with 4 ecosites and 2 degradation conditions. Variability (measured as variance) increases as the number of ecosites increases, however, some ecosites add more variance than others. Limiting the number of ecosites and conditions can reduce the number of samples or measurements required to detect change.

}, keywords = {abstract, inference, monitoring, sampling, SRM}, author = {S.A. Wills and Jeffrey E. Herrick and A.J. Tugel} } @conference {50170, title = {Image-based rangeland monitoring at multiple scales}, booktitle = {2008 Joint Meeting 21st International Grassland Congress / 8th International Rangeland Congress}, year = {2008}, month = {2008}, abstract = {Introduction: Sustainable rangeland management is enhanced by accurate ecological assessments and these, in turn, can be enhanced by advancing technology and decreasing labor costs. Image-based, multi-scale monitoring can reduce data-collection costs and reveal pattern and process (Wu 1999) to allow, for example, assessing the relationship between the functional integrity of ecosystems and biodiversity across regions (Ludwig et al. 2004). Here we examine the potential benefits of image-based, multi-scale monitoring protocols. Materials \& Methods: Fifty plots were located in 4 plant communities of the Jornada Experimental Range (JER), NM, USA. Ground cover for the plots was obtained using, (a) 1-mm ground sample distance (GSD) ground-based images analyzed with object-based image-analyses methods, and (b) the line-point-intercept (LPI) sampling method (Laliberte et al., 2007a). A QuickBird satellite image acquired over the study area was segmented at 4 different scales, resulting in a hierarchical network of image objects representing the image information in different spatial resolutions (Laliberte et al., 2007b). This allowed for differentiation of individual shrubs at fine scales and delineation of broader vegetation classes at coarser scales. At the Central Plains Experimental Range (CPER), CO, USA, 1-mm GSD images were acquired for 200 locations across 3 pastures using ground and aerial photography (Booth and Cox, In Press). Ground cover was measured from the CPER images using {\textquoteleft}SamplePoint{\textquoteright} software.Results \& Discussion: Image acquisition and object-based analysis for ground cover at JER gave 80\% correlation with LPI data but required half the labor. Work at CPER complemented that at JER in that 1-mm GSD imagery obtained from the ground or the air was equally effective for detecting ground-cover differences due to pasture stocking rate, thus demonstrating the potential to save data-collection time and cost by aerial image acquisition. The combination of multi-resolution image segmentation and decision tree analysis of the QuickBird image facilitated the selection of input variables and helped in determining the appropriate image-analysis scale, thus enhancing vegetation-mapping accuracy over conventional methods. Conclusions: Image-based monitoring using 1-mm GSD ground or aerially acquired images reduces data-collection costs; multi-scale data expands pattern detection possibilities enhancing vegetation mapping accuracy. Together these technologies contribute to our rangeland monitoring and sustainable-management capacity.}, keywords = {image-based, rangeland management}, url = {/files/bibliography/08-049.pdf}, author = {Booth, D.T. and Andrea S. Laliberte and A. Rango and Jeffrey E. Herrick} } @proceedings {50177, title = {Integrating terrestrail sequestration into a national greenhouse gas management program}, year = {2008}, month = {2008}, abstract = {Terrestrial sequestration is the deliberate process of storing carbon in the soil or vegetation via the net effect of naturally occurring processes (photosynthesis, leading to storage in plants; humification and aggregation, leading to conversion of plant carbon to soil carbon; and respiration, which returns some plant and soil carbon to the atmosphere as CO2). Removing carbon from the atmosphere via terrestrial sequestration has been proposed as a critical element in the portfolio of actions to stabilize greenhouse gases in the atmosphere and avoiding undesirable climate change. One benchmark for integrating terrestrial sequestration into a GHG management plan might be to increase sequestration beyond {\textquotedblleft}business-as-usual{\textquotedblright} levels by an average of about 1-2 PgC/yr during the next 50 years. Assuming this benchmark is accomplished by a linear increase in sequestration rates, the integrated total over 50 years would be 25-50 PgC. Achieving this level of performance will require 1) improvements in existing understanding of sequestering processes, 2) more focused incentive programs to accelerate adoption and maintenance of sequestering practices and 3) an enhanced monitoring and verification effort to insure credibility.}, keywords = {carbon, sequestration, terrestrail}, author = {Joel R. Brown and Sampson, N.} } @conference {50213, title = {Incorporating invasive species and degraded landscapes into ecological site descriptions}, booktitle = {Society for Range Management Annual Meeting}, series = {Building Bridges: Grasslands to Rangelands}, year = {2008}, month = {January 26-31, 2}, pages = {2100}, address = {Louisville, KY}, abstract = {Ecological Site Descriptions (ESDs) and State-and-Transition Models (STMs) have been developed as means of evaluating the condition of rangelands based on Historic Climax Plant Communities (HCPCs) and for creating land management plans with an understanding of the dynamics of vegetation change. However, with the overall increase of invasive species, either native or exotic, along with natural or man-made land degradation, it is difficult to find sites not influenced by invasive species or changes in site-defining soil properties. In some areas, all available sites may be dominated by invasive species and/or extensively degraded. Although STMs have been developed to include potential states caused by simple disturbances such as long-term overgrazing and increased fire frequency, it is often difficult to create STMs that integrate processes that permanently change an area to a new or modified ecological site. In addition, it is difficult to define reference conditions in extensively altered ecological sites in a way that incorporates the former HCPC and the new ecological site properties. This poster will explore possible solutions for writing ESDs and STMs for sites influenced by invasive species and severely degraded landscapes, along with the strengths and weaknesses of these solutions.}, keywords = {degraded, ecological site descriptions, invasive}, author = {N.K. Hansen and Brandon T Bestelmeyer and Joel R. Brown and A.J. Tugel} } @proceedings {50232, title = {Incorporation of texture, intensity, hue, and saturation for rangeland monitoring with unmanned aircraft imagery}, volume = {XXXVII}, year = {2008}, month = {08/2008}, pages = {4/C1}, address = {Calgary, Canada}, abstract = {Aerial photography acquired with unmanned aerial vehicles (UAVs) has great potential for incorporation into rangeland health monitoring protocols, and object-based image analysis is well suited for this hyperspatial imagery. A major drawback, however, is the low spectral resolution of the imagery, because most lightweight cameras suitable for UAVs only acquire imagery in the red, green, and blue bands (RGB). Potential solutions include the incorporation of intensity, hue, and saturation (IHS) and/or texture measures. The use of texture had improved classification results in a related study, but we wanted to investigate whether IHS would yield similar results, because texture calculations in object-based analysis are computer intensive. Our objectives were to determine the optimal analysis scale and optimal band combinations: RGB, RGB+texture, RGB+IHS, or RGB+IHS+texture. Eight aerial photos were mosaicked and segmented at 15 consecutively coarser scale parameters (from 10 to 80) using the object-based image analysis program Definiens Professional. Class separation distances, classification accuracies and Kappa Index of Agreement were used to assess the classifications. The highest classification accuracies were achieved at segmentation scales between 50 and 70 and were consistently in the high 90\% range, regardless of which bands were included. The inclusion of texture measures increased classification accuracies at nearly all segmentation scales, but the use of RGB+IHS alone resulted in comparable accuracies at most scales and with considerably less computation time. Techniques used in this study offer an objective approach for determining segmentation scale, and for selecting bands useful for rangeland mapping with hyperspatial, low spectral resolution imagery.}, keywords = {aerial, hyperspatial, imagery, monitoring, object-based, proceedings, rangeland health, UAV}, url = {/files/bibliography/08-046.pdf}, author = {Andrea S. Laliberte and A. Rango} } @inbook {50261, title = {Introduction to Snow Hydrology}, booktitle = {Principles of Snow Hydrology}, year = {2008}, month = {July 2008}, pages = {1-19}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, chapter = {1}, address = {Cambridge, NY}, abstract = {

There are many fallacies or misconceptions about snow and its importance in the environment. One good example of this is found in the Rio Grande Basin in the Southwestern United States and Mexico. The Rio Grande, the third longest river in the United States, is sustained by snow accumulation and melt in the mountain rim regions which provide a major contribution to the total streamflow, despite flowing right through the heart of North America\’s largest desert (Chihuahuan). Because the majority of the population in the basin resides in a few large cities in the Rio Grande Valley, which are all located in the desert there is little realization on the part of the urban residents that snowmelt is an important factor in their lives. This is true around the globe. Where agricultural water use predominates, however, the importance of snow for the water supply and food production is more widely known, although to a markedly smaller proportion of the population.

}, keywords = {hydrology, introduction, Rio Grande, snow, southwestern}, 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 {50319, title = {Improving estimates of rangeland carbon storage}, booktitle = {60th Annual Meeting of the Society for Range Management}, year = {2007}, month = {February 9-16, 2}, pages = {Paper No. 55}, address = {Sparks/Reno, Nevada}, abstract = {Terrestrial carbon sequestration on rangelands has the potential to make a substantial contribution to the reduction of greenhouse gas (GHG) levels in the atmosphere and mitigate the effects of global climate change. This enhanced sequestration can be accomplished through the management of soils and vegetation, primarily on land that is used for production of domestic livestock and wildlife habitat. In most cases, management methods to increase sequestration rates are compatible with, and support, conservation and production objectives. The primary barriers to adoption of sequestering practices and 1) the short-term costs and risks associated with changing land use or land management regimes, 2) high spatial and temporal variability in the processes that drive carbon dynamics, and 3) lack of reliable measurement technologies and reliable models for prediction of long-term sequestration and related effects in many rangeland ecosystems. Our analysis of southwestern US rangelands identified limited opportunities to enhance sequestration on intact rangelands, due primarily to low and erratic rainfall. We also identified potentially significant gains in the conversion of existing cropland to permanent vegetative cover, especially in areas with more reliable precipitation and mollisols. Increasing carbon storage on southwestern US rangelands will require programs that encompass large areas and implementation of new technologies to validate the changes in carbon.}, keywords = {carbon, GHG, global climate, greenhouse gas, rangelands, terrestrial}, author = {Joel R. Brown and Angerer, J.} } @article {50333, title = {Influence of habitat characteristics on detected site occupancy of the New Mexico endemic Sacramento Mountains salamander, Aneides hardii}, journal = {Journal of Herpetology}, volume = {41}, number = {1}, year = {2007}, month = {March 2007}, pages = {1-8}, abstract = {The Sacramento Mountains Salamander (Aneides hardii) is a state-listed threatened species endemic to three mountain ranges in south central New Mexico. Information about the ecological requirements of this species is inadequate for managers to make informed conservation decisions, yet changes in management practices are needed throughout the species range because of poor forest health. During summer 2004, we examined patterns of A. hardii distribution in relation to several abiotic and biotic parameters on 36 plots, each of which was 9.6-ha in area and located in mixed conifer forest. We evaluated 18 a priori logistic regression models using Akaike{\textquoteright}s Information Criterion corrected for small-sample bias (AICc). The model with the highest ranking (= lowest AICc value) included soil moisture and soil temperature as predictive variables, and the second highest ranked model (AICc = 0.05) included only soil temperature. Soil temperature was lower, and soil moisture was higher on plots where salamanders were detected. The relative importance of canopy cover and log volume was low in this study likely because the study plots had similar disturbance history. We recommend managers focus on practices that ensure salamander microhabitats remain cool and moist in conservation areas.}, keywords = {Aneides hardii, New Mexico, Sacramento Mountains, salamander}, url = {/files/bibliography/07-006.pdf}, author = {S. Haan and Desmond, M.J. and W. R. Gould and J.P. Ward} } @conference {50359, title = {Identification of seed borne endopohytes that confere salt tolerance to host plants}, booktitle = {Plant Biology and Botany 2007 Annual Meetings}, year = {2007}, month = {July 7-11, 2007}, address = {Chicago, IL}, abstract = {The chenopod halophyte, Atriplex canescens (Pursh) Nutt, (fourwing saltbush) is broadly distributed among western rangelands. Its highly variable phenotypes are typically attributed to varied ploidy levels. However, A. canescens is also associated with complex communities of seed borne endophytes. Microscopic examination of these endophytes communities suggests potential roles in stress tolerance. In this study, observational and experimental data are being combined to evaluate microbial contributions to salt tolerance of A. canescens. Initially, Ecological Site Descriptions published through the National Resource Conservation Service are used to identify five optimal and five extreme saline habitats populated with A. canescens. Seeds collected from identified habitats are surface disinfested, and microbes associated with seeds germinating in vitro are characterized using direct isolation and/or denaturing gradient gel electrophoresis (DGGE), followed by sequencing of ribosomal RNA genes (rDNA). At present, four ascomycete fungi and two bacterial species have been isolated. To analyze the manner in which these microbes influence host plant salt tolerance, microbes are transferred to various species of aseptically propagated host plants. Treated and untreated plants are exposed to a range of saline conditions and plant growth is compared across treatments. These rapid bioassays are expected to reveal plant-endophyte combinations with potential to increase plant tolerance to saline conditions.}, keywords = {endopohytes, salt tolerance}, author = {M.E. Lucero and J.R. Barrow and Ruth L. Sedillo and I. Reyes-Vera and Caitriana Steele and Midez, J.} } @article {50364, title = {The impact of connectivity on the modelling of overland flow within semi-arid shrubland environments}, journal = {Water Resources Research}, volume = {43}, year = {2007}, note = {//USDA//LTER-V//entered 08/15/2007; updated 11/20/2007 (electronic journal article)}, month = {2007}, abstract = {

The objective of this study is the evaluation of the spatial variability and intrinsic connectivity features of model input parameters for the parameterization of process-based, spatially distributed overland flow models. Parameter scaling tools based on the statistical and geostatistical properties of an extensive field data set were developed. These allowed the reproduction of the spatial heterogeneity of model parameters associated with the soil- and vegetation related properties of semi-arid shrubland environments to a varying degree. The outcome of the study emphasizes that connectivity plays a fundamental role in the modeling of water fluxes within semi-arid catchments. The larger the degree to which connected features are represented, the better the model performance. In contrast, the parameterization approaches that did not contain connected patterns of parameter values performed comparatively poorly. A spatially connected overland flow model therefore enabled the generation of realistic overland flow patterns that qualitatively resembles field surveys of overland flow generation not only at the outlet of the model domains, but also within the catchments without the need of calibration.

}, keywords = {article, dirt tanks, hydrology, hydrology, connectivity, hydrology, dirt tanks, hydrology, model, hydrology, overland flow, journal, model, connectivity, model, hydrology, model, overland flow, model, water fluxes}, doi = {10.1029/2006WR005006}, url = {files/bibliography/JRN00485.pdf}, author = {Eva N. M{\"u}ller and John Wainwright and A.J. Parsons} } @article {50379, title = {Influence of secondary compound complementarity and species diversity on consumption of Mediterranean shrubs by sheep}, journal = {Applied Animal Behavior Science}, volume = {107}, year = {2007}, month = {September 7, 200}, pages = {58-65}, abstract = {Generalist herbivores foraging in chemically diverse grazing ecosystems like the Mediterranean maquis increase intake on mixed diets, suggesting they are more able to meet nutritional needs and avoid toxicosis. Thus, our objectives were to determine how shrub species diversity and complementary interactions between tannins and saponins influence intake of Mediterranean shrubs by sheep. We conducted four experiments comparing intake of mixtures of Mediterranean shrub mixtures varying in number of species and/or principal class of secondary compound (tannins or saponins) by sheep (n = 12). Sheep consumed more total foliage (P < 0.01) when offered a high-tannin shrub (Pistacia lentiscus; Exp. 1), two high-tannin shrubs (Pistacia lentiscus and Arbutus unedo; Exp.2), or three high-tannin shrubs (Pistacia lentiscus, Arbutus unedo, and Quercus ilex; Exp. 3) when fed in conjunction with a high-saponin shrub (Hedera helix) than with an equal number of high-tannin shrubs (20.94 vs. 16.32 g/kg BW; 28.76 vs. 20.77 g/kg BW, and 35.34 vs. 26.85 g/kg BW). Likewise, sheep ate more foliage (P < 0.01) of each individual shrub (Pistacia lentiscus, Arbutus unedo, and Quercus ilex) in the mixture when fed with Hedera helix than with an equal number of high-tannin shrubs (8.17 vs. 4.95 g/kg BW; 13.28 vs.10.68 g/kg BW, and 7.62 vs. 5.16 g/kg BW), suggesting a complementary interaction between tannins and saponins may have occurred. Sheep also appeared to increase total shrub intake as number of shrub species on offer increased, regardless of number of classes of compounds present. Our findings suggest that secondary compounds in Mediterranean shrubs (tannins and saponins) are complementary. Species diversity also plays an important role in diet selection, as plant species with different types and amounts of nutrients and phytotoxins may affect forage intake and animal production. This knowledge may be useful for livestock producers to capitalize on phytochemical interactions to improve performance of livestock foraging on Mediterranean shrublands.}, keywords = {consumption, diversity, herbivores, mediterranean, sheep}, url = {/files/bibliography/07-025.pdf}, author = {Rogosic, J. and Richard E. Estell and Skobic, D. and Stanic, S.} } @article {50409, title = {Impacts of biological soil crust disturbance and composition on C and N loss from water erosion}, journal = {Biogeochemistry}, volume = {77}, year = {2006}, month = {01/2006}, pages = {247-263}, chapter = {247}, abstract = {

In this study, we conducted rainfall simulation experiments in a cool desert ecosystem to examine the role of biological soil crust disturbance and composition on dissolved and sediment C and N losses. We compared runoff and sediment C and N losses from intact latesuccessional dark cyanolichen crusts (intact) to both trampled dark crusts (trampled) and dark crusts where the top 1 cm of the soil surface was removed (scraped). In a second experiment, we compared C and N losses in runoff and sediments in early-successional light cyanobacterial crusts (light) to that of intact late-successional dark cyanolichen crusts (dark). A relatively high rainfall intensity of approximately 38 mm per 10-min period was used to ensure that at least some runoff was generated from all plots. Losses of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and ammonium (NH4 + ) were significantly higher from trampled plots as compared to scraped and intact plots. Sediment C and N losses, which made up more than 98\% of total nutrient losses in all treatments, were more than 4-fold higher from trampled plots relative to intact plots (sediment C g/m2, intact = 0.74, trampled = 3.47; sediment N g/m2, intact = 0.06, trampled = 0.28). In light crusts, DOC loss was higher relative to dark crusts, but no differences were observed in dissolved N. Higher sediment loss in light crusts relative to dark crusts resulted in 5-fold higher loss of sediment-bound C and N. Total C flux (sediment + dissolved) was on the order of 0.9 and 7.9 g/m2 for dark and light crusts, respectively.\  Sediment N concentration in the first minutes after runoff from light crusts was 3-fold higher than the percent N of the top 1 cm of soil, suggesting that even short-term runoff events may have a high potential for N loss due to the movement of sediments highly enriched in N. Total N loss from dark crusts was an order of magnitude lower than light crusts (dark = 0.06 g N/m2, light = 0.63 g/m2). Overall, our results from the small plot scale (0.5 m2) suggest that C and N losses are much lower from intact late-successional cyanolichen crusts as compared to recently disturbed or early-successional light cyanobacterial crusts.

}, keywords = {Biological soil crust, Canyonlands National Park, carbon, Colorado Plateau, disturbance, erosion, nitrogen, rainfall simulation, runoff}, doi = {10.1007/s10533-005-1424-7}, url = {/files/bibliography/06-070.pdf}, author = {N. Barger and Jeffrey E. Herrick and Justin Van Zee and Jayne Belnap} } @conference {50437, title = {The importance of soil carbonates for available water holding capacity in arid ecosystems of the Americas}, booktitle = {Ecology International Congress}, year = {2006}, month = {January 10, 2006}, pages = {Paper No. 59106}, address = {Merida, Mexico}, abstract = {Petrocalcic and calcic soil horizons develop extensively in arid and semi-arid ecosystems across more than 15\% of the Americas. Many of these horizons occur within the rooting zone of grasses and row crops and all are within the rooting depths of deep rooted desert shrubs. The accumulation of calcium carbonate in coarse textured soils can produce a dramatic change in water holding capacity through the conversion of a soil horizon dominated by large pores to a fine pore matrix. Understanding soil available water holding capacity (AWHC) is important for both forage and row crop production systems. Soil AWHC can control production and plant community composition by affecting the spatial and temporal patterns of plant available water. We conducted laboratory experiments and field surveys assessing the importance of carbonate accumulation for soil profile AWHC and the temporal availability of plant available water in high carbonate soils in southern New Mexico, USA. The added water holding capacity due to carbonates more than doubled the AWHC of some coarse textured soils but was less important in fine textured soils. Many high carbonate soil horizons, even horizons cemented with calcium carbonate, received substantial increases in soil water content during periods of winter recharge. Petrocalcic and partially indurated calcic horizons are often overlooked when assessing soil profile available water. This study indicates that petrocalcic and calcic horizons can contain significant amounts of plant available water and are important when assessing soil available water holding capacity.}, keywords = {calcic, Petrocalcic, semi-arid}, author = {Danielle Duni and Jeffrey E. Herrick and Curtis H. Monger} } @article {50439, title = {Introduction to special issue - Landscape linkages and cross scale interactions in arid and semiarid ecosystems}, journal = {Journal of Arid Environments}, volume = {65}, year = {2006}, month = {April 2006}, pages = {193-195}, abstract = {The conversion of grasslands to shrublands in arid and semiarid ecosystems is a serious global problem. Although a great deal of research has been conducted on these conversions, we lack a complete understanding of the processes underlying the transitions. More importantly, our ability to predict when and where desertification will occur and our ability to manage landscapes to prevent degradation and restore degraded landscapes is limited. Research being conducted at the Jornada Experimental Range (JER) is addressing these problems in a new, synthetic way. Since 1981, scientists affiliated with the Jornada Basin Long-Term Ecological Research site in collaboration with scientists from the JER and New Mexico State University generated a number of new ideas and concepts regarding the processes governing desertification that changed our thinking about how these systems operate. Our focus now emphasizes cross-scale spatial and temporal heterogeneity in vegetation patterns and dynamics that have been difficult to explain using traditional approaches. The realization that our current knowledge often cannot explain the existing variability among land units led to the development of a conceptual model by JER scientists that considers nonlinear dynamics and connections among land units across scales. This cross-scale landscape ecology approach will further our understanding of critical processes occurring in arid regions globally and will provide insight to help identify mechanisms to address the pressing issue of desertification.}, keywords = {arid, cross scale, desertification, ecosystems, invasion, landscape, linkages, semiarid, shrub}, doi = {10.1016/j.jaridenv.2005.04.001}, url = {/files/bibliography/06-006.pdf}, author = {Richard E. Estell and E.L. Fredrickson and Debra C. Peters} } @inbook {50448, title = {Introduction}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {3-14}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {1}, address = {New York, NY}, abstract = {Arid lands throughout the world, including lands at the border of arid regions, are increasingly subject to human impact, leading to degradation of soils, losses of plant production, and a diminished economic potential to support human populations. Focusing on the human impact and consequent losses in economic potential, we often call these changes \"desertification.\" With the potential for global climate change, however, the definition of desertification and its potential must be expanded. Indeed, the 1992 United Nations\’ Desertification Convention defined desertification as \"land degradation in arid, semiarid and dry subhumid areas resulting from various factors, including climatic variations and human activities.\" It is more recently recognized that desertification involves human and environmental drivers but is a symptom evident at regional spatial scales that emerges from degradation at finer spatial scales. Assertions relative to an updated and revised paradigm regarding desertification have been developed. In l981, a group of scientists based in Las Cruces, New Mexico, and associated with New Mexico State University proposed a program of long-term ecological research in the Jornada Basin of southern New Mexico (USA) to gain a better understanding of processes that determine the structure and function of desert ecosystems. To an extent, this book represents both a synthesis of that effort and a benchmark of our progress over the last 23 years. In addition, this book draws on a longer history of research in the Jornada Basin that dates back to the early part of the twentieth century. Both the group and its mission have evolved since 1981, but an initial motivation for our studies was the dramatic, historic records of vegetation change in the Jornada.}, keywords = {Chihuahuan Desert, introduction, Jornada Basin, LTER, synthesis book}, url = {/files/bibliography/06-052.pdf}, author = {Kris Havstad and W. H. Schlesinger}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @article {50457, title = {An integrated framework for science-based arid land management}, journal = {Journal of Arid Environments}, volume = {65}, number = {2}, year = {2006}, month = {2006}, pages = {319-335}, abstract = {

Our objective is to develop a science-based management framework for arid and semiarid ecosystems. This framework must facilitate the integration of new knowledge about linkages among landscape units across scales. Science is frequently touted as the solution to dryland management problems, yet most management decisions are, of necessity, based primarily on expert knowledge and experience. This paper describes an integrated framework for organizing, synthesizing, and applying our growing understanding of dryland ecosystems using a flexible, multi-objective assessment, monitoring, and management approach. The framework is dual-purpose: (1) to coordinate the use of existing tools, resources, and diffuse knowledge, and (2) to facilitate the integration and application of new knowledge as it is developed. The framework includes five elements: (1) an ecological, site-based approach for categorizing land based on soils and climate; (2) a repository for organizing existing data and knowledge about each ecological site; (3) conceptual models that organize information on the impacts of management and climate variability; and, protocols for (4) assessing and (5) monitoring key ecosystem attributes fundamental to a variety of management objectives. Within this framework, basic and applied research are explicitly linked to management of arid and semiarid ecosystems to more effectively articulate research questions and set research priorities.

}, keywords = {arid, ecosystems, land mangement, science-based, semiarid}, doi = {10.1016/j.jaridenv.2005.09.003}, url = {/files/bibliography/06-003.pdf}, author = {Jeffrey E. Herrick and Brandon T Bestelmeyer and Steven R. Archer and A.J. Tugel and Joel R. Brown} } @conference {50481, title = {Interpreting Indications of Rangeland Health, Version 4}, booktitle = {Society for Range Management Annual Meeting Abstracts}, number = {Paper No. 278}, year = {2006}, month = {February 12-17, }, address = {Vancouver, British Columbia, Canada}, abstract = {Land managers are in need of an assessment tool that provides a preliminary evaluation of rangeland health. Interpreting Indicators of Rangeland Health, Version 4 is the second published version of a protocol that uses 17 easily observed indicators summarized as three rangeland health attributes (soil/site/stability/hydrologic function, and biotic integrity). Version 3 was published in 2000 and has been widely used in the United States by land management agencies and technical assistance specialists. The changes in Version 4 build up the Version 3 framework and increase the consistency in the application of the protocol in two ways. The most significant modification is the replacement of the ecological site description and/or reference area(s) with an ecological site-specific reference sheet as the standard for the evaluation process. The reference sheet integrates all available sources of data and knowledge, including the ecological site description and reference areas, to generate a range of reference values for each indicator. The reference sheet will be included in ecological site descriptions as they are updated. A second significant modification is the addition of recommended quantitative measurements to support the qualitative evaluations. Version 4 is currently being translated into Chinese, Mongolian, and Spanish.}, keywords = {management, rangeland health}, author = {M. Pellant and P. L. Shaver and D.A. Pyke and Jeffrey E. Herrick} } @article {50489, title = {Integrating patch and boundary dynamics to understand and predict biotic transitions at multiple scales}, journal = {Landscape Ecology}, volume = {21}, year = {2006}, month = {2006}, pages = {19-33}, abstract = {

Human modification of landscapes superimposed upon natural environmental heterogeneity is resulting in an increase in the numbers and types of ecological patches and their intervening boundaries (i.e., biotic transitions). In this paper, we develop an operational framework for understanding and predicting dynamics of these biotic transitions for a range of environmental conditions across multiple spatial scales. We define biotic transitions as the boundary and the neighboring states, a more general definition than typically denoted by the terms boundary, ecotone, edge or gradient. In our framework, we use concepts of patch dynamics to understand the structural and functional properties of biotic transitions, and to predict changes in boundaries through time and across space. We develop testable hypotheses, and illustrate the utility of our approach with examples from arid and semiarid ecosystems. Our framework provides new insights and predictions as to how landscapes will respond to future changes in climate and other environmental drivers.

}, keywords = {Directional transitions, ecotones, Positive feedbacks, Shifting transitions, Stationary transitions}, doi = {10.1007/s10980-005-1063-3}, url = {/files/bibliography/06-014.pdf}, author = {Debra C. Peters and J. R. Gosz and Pockman, W.T. and Small, E.E. and Paramenter, R.E. and S.L. Collins and E. Muldavin} } @article {50493, title = {Islands of hydrologically enhanced biotic productivity in natural and managed arid ecosystems}, journal = {Journal of Arid Environments}, volume = {65}, year = {2006}, month = {April 1, 2006}, pages = {235-252}, abstract = {

The objective of this paper is to examine the spatial variability of islands of enhanced hydrologic
activity and its application to remediation of degraded arid and semi-arid ecosystems. Factors
causing high spatial variability of water in arid regions include precipitation, soil, physiography, and
vegetation. Inherent heterogeneity of arid lands causes areas of runoff and run-on which lead to
development of islands of hydrologically enhanced biotic productivity. These hydrologic islands are
observed at the individual plant scale as well as in large area patterns of banded vegetation, playettes and playas, and beaded drainage networks where run-on and infiltration stimulate vegetation
growth. To remediate degraded rangeland, it may be prudent to mimic nature by diverting water to
target areas to create patterns similar to natural islands of hydrologically enhanced biotic
productivity. Installation of structures such as water ponding dikes can promote changes to natural
vegetation patterns at a landscape scale.

}, keywords = {enhanced biotic productivity, heterogeneity, rangeland, remediation, run-on, runoff, water ponding dikes}, doi = {10.1016/j.jaridenv.2005.09.002}, url = {/files/bibliography/06-009.pdf}, author = {A. Rango and S. Tartowski and Andrea S. Laliberte and John Wainwright and A.J. Parsons} } @conference {50499, title = {An international research network for testing the Dahlem Desertification Paradigm (DDP)}, booktitle = {Global Environmental Change: Regional Challenges. An Earth System Science Partnership, Open Science Conference}, year = {2006}, month = {November 9-12, 2}, pages = {661}, address = {Beijing, China}, abstract = {Historically, debates associated with global desertification have focused on the underlying causes of land degradation; the extent to which changes are natural (e.g., climate-driven) vs. anthropogenic (e.g., over-grazing); {\textquoteleft}grass-roots{\textquoteright} abatement efforts vs. scientific ones; the amount of land affected or {\textquoteleft}at risk{\textquoteright}; and whether or not desertification is reversible. Since stakeholders tend to employ disciplinary arguments in the debate, the end product is confusion and disagreement. Hence, there is an urgent need for new thinking beyond regional and disciplinary concerns. We argue that when desertification is viewed in the context of coupled human environmental systems, many of the scientific, political and social issues of desertification seem tractable. We have developed a new synthetic framework: the Dahlem Desertification Paradigm (DDP), which consists of 9 assertions and yields testable hypotheses to move the debate forward. We are applying the DDP to diverse ecosystems throughout the world via ARIDnet (assessment, research, and integration of desertification research network), an international initiative that emphasizes the importance of interdependencies of natural and human systems. The general objectives of ARIDnet are to foster international cooperation and exchange of ideas about desertification as summarized in the DDP; to open communication channels to foster more practical, field-level interactions with stakeholders in sustainable land management; and to use the concepts, experiences, and applications developed by participants to support on-going international discussions on the principles, criteria, and policies related to global desertification, especially the Convention to Combat Desertification.}, keywords = {climate, global desertification, natural}, author = {J. F. Reynolds and M. Ayarza and Jeffrey E. Herrick and E. Huber-Sannwald and E. Lambin and D. Mark Stafford Smith} } @article {50513, title = {Influence of plant material handling protocols on terpenoid profiles of one-seed Juniper saplings}, journal = {Rangeland Ecology and Management}, volume = {59}, year = {2006}, month = {November 1, 2006}, pages = {668-673}, abstract = {Accurate estimation of one-seed juniper (Juniperus monosperma (Englem). Sarg.) intake by goats and sheep often requires harvesting, transporting, and storing plant material that is later used in pen experiments. Such manipulation could alter terpenoid profiles and modify herbivory levels significantly. We used gas chromatography mass spectrometry (GC/MS) to analyze the terpenoid profile of the ethanol extract of leaves of small and large one-seed juniper saplings subjected to three different handling protocols. Plant materials were either: a) placed on dry ice after clipping and then at -80\º C until analysis (Control); b) stored at ambient temperature during the first 24 hours and then frozen; or c) stored at ambient temperature during the first 24 hours, and then stored at 8\ºC for 3 weeks. Juniper saplings contained a mixture of 51 terpenoids, three of which were unknown compounds. Only 14 terpenoids accounted for 95\% of the total volatiles extracted. Alpha-pinene was the most abundant compound, accounting for 65\% of total terpenoid concentration. Total terpenoid content did not differ among handling protocol treatments (Control: 21,682.19 \±1,424.72 \&$\#$39;g g-1 DM; Frozen after 24 h: 19,553.63 \±1,081.88 \&$\#$39;g g-1 DM; Refrigerated for three weeks: 18,799.89 \±1,126.03 \&$\#$39;g g-1 DM). Handling protocols appeared to induce only slight variations in a small number of minor terpenes. We detected large among-plant variation in terpenoid profiles that was not fully explained by sapling size. This study suggests that juniper feeding trials can be simplified using plant material stored at 8\ºC for three weeks without significant alteration of terpenoid profiles. Among-plant variation in chemical composition, however, must be considered in pen feeding trials. http://www.bioone.org/perlserv/?request=get-pdf\&doi=10.2111\%2F06-010R1.1}, keywords = {gas chromatography, handling protocols, one seed juniper, terpenoids}, url = {/files/bibliography/06-041.pdf}, author = {S. A. Utsumi and Andr{\'e}s F. Cibils and Richard E. Estell and Yi Wang} } @conference {50531, title = {Innovation and Opportunities in Livestock Control using Virtual Boundaries (VBS TM)}, booktitle = {Proceedings International Conference on Agricultural Science and Technology}, year = {2005}, month = {April 26-29, 200}, pages = {29-30}, address = {Venture, California}, abstract = {Control, in the context of managing free-ranging animals, most assuredly conjures up thoughts of conventional fencing. Substitute the term conventional fencing with Virtual Boundary (VB\™) and you are catapulted into the space age where electronic control of innate animal behaviors has been developed into a patented methodology termed Directional Virtual Fencing (DVF\™). DVF\™ provides a low stress, highly flexible, autonomous method of controlling free-ranging animals. The control of animals behind an invisible barrier originated in the mid 1970\’s with small area pet containment systems. However, during the late 1960\’s and early 1970\’s the Global Positioning System (GPS) of navigation satellites deployed by the US military resulted in a key piece of technology for DVF\™ animal control. On April 2, 2002, the first observation of a free-ranging beef cow controlled using DVF\™ was recorded. Since then the US Department of Agriculture research on the Jornada Experimental Range in New Mexico has established proof-of-concept that free-ranging beef cattle and sheep can be controlled behind a static VB\™. Also it was shown that animals could be moved over a landscape in much the same way rotational grazing systems currently move animals, but without the need for conventional fences. Current field trials are focused on optimizing the protocol to gather animals into a corral using a moving VB\™. Research continues on miniaturizing the physical size of the DVF\™ device worn by the animal and reducing power needed from batteries and solar energy. Once DVF\™ is commercialized, it is realistic to envision free-ranging animals as programmable harvesting tools capable of providing prescribed vegetation utilization based on ecological goals while simultaneously providing adequate nutrition for optimum animal production.}, keywords = {control, livestock, VBS, virtual boundaries}, author = {D.M. Anderson} } @book {50587, title = {Interpreting Indicators of Rangeland Health, Version 4.0}, volume = {1734-6}, year = {2005}, month = {September 2005}, publisher = {USDI, BLM, NSTC, Division of Science Integration, Branch of Publishing Services}, organization = {USDI, BLM, NSTC, Division of Science Integration, Branch of Publishing Services}, address = {Denver, CO}, abstract = {This book describes a protocol for using 17 qualitative soil and vegetation indicators to evaluate the status of three ecosystem attributes: soil and site stability, hydrologic function, and biotic integrity. Qualitative assessments of rangeland health provide land managers and technical assistance specialists with a good communication tool for use with the public. Many of these tools have been used successfully for this purpose over the past 100 years. The technique described in this book can be used to provide early warnings of resource problems on upland rangelands. It can also be used to help identify specific resource issues (e.g., erosion or invasive species) that must be addressed and to prioritize land for management resources. Version 4 is the second published edition of this technique. The changes in Version 4 are designed to improve the consistency in the application of the process. The most significant modification was the replacement of the Ecological Reference Area Worksheet with the Reference Sheet. The Reference Sheet facilitates consistent application of the process throughout an ecological site by integrating all available sources of data and knowledge to generate a single range of reference conditions for each indicator. }, keywords = {ecosystem attributes, evaluate, indicators, interpreting, rangeland health, soil, technical reference, vegetation}, url = {/files/bibliography/05-010.pdf}, author = {M. Pellant and P. L. Shaver and D.A. Pyke and Jeffrey E. Herrick} } @article {50596, title = {Interacting effects of landownership, land use, and endangered species on conservation of southwestern U.S. rangelands}, journal = {Conservation Biology}, volume = {19}, year = {2005}, month = {June 2005}, pages = {783-792}, chapter = {783}, abstract = {The contemporary southwestern United States is characterized by fire-adapted ecosystems; large numbers of federally listed threatened and endangered species; a patchwork of federal, state, and private landownership; and a long history of livestock grazing as the predominant land use. I compared eight sites in southern Arizona and New Mexico to assess the interacting effects of these characteristics on conservation practices and outcomes. There was widespread interest and private-sector leadership in restoring fire to southwestern rangelands, and there is a shortage of predictive scientific knowledge about the effects of fire and livestock grazing on threatened and endangered species. It was easier to restore fire to lands that were either privately owned or not grazed, in part because of obstacles created by threatened and endangered species on grazed public lands. Collaborative management facilitated conservation practices and outcomes, and periodic removal of livestock may be necessary for conservation, but permanent livestock exclusion may be counterproductive because of interactions with land-use and landownership patterns.}, keywords = {collaborative management, Endangered Species Act, fire, livestock grazing, riparian areas, threatened species}, url = {/files/bibliography/05-026.pdf}, author = {N. F. Sayre} } @article {50646, title = {Invasion in space and time: non-native species richness and relative abundance respond to interannual variation in productivity and diversity}, journal = {Ecology Letters}, volume = {7}, year = {2004}, note = {//NMSU, USDA//LTER IV//}, month = {2004}, pages = {947-957}, abstract = {

Ecologists have long sought to understand the relationships among species diversity, community productivity and invasion by non-native species. Here, four long-term observational datasets were analyzed using repeated measures statistics to determine how plant species richness and community resource capture (i.e., productivity) influenced invasion. Multiple factors influenced the results, including the metric used to quantify invasion, interannual variation and spatial scale. Native richness was positively correlated with non-native richness, but was usually negatively correlated with non-native abundance, and these patterns were stronger at the larger spatial scale. Logistic regressions indicted that the probability of invasion was reduced both within and following years with high productivity, except at the desert grassland site where high productivity was associated with increased invasion. Our analysis suggests that while non-natives were most likely to establish in species rich communities, their success was diminished by high resource capture by the resident community.

}, keywords = {article, articles, journal, journals, plant productivity, plant, biodiversity, plant, diversity, plant, interannual variability, plant, invasion, plant, logistic regression, plant, relative abundance, plant, repeated measures, plant, resources, plant, species richness, plant, synthesis, statistical methods, logistic regressions, statistical methods, repeated measures, statistical methods, synthesis}, doi = {10.1111/j.1461-0248.2004.00655.x}, url = {files/bibliography/JRN00411.pdf}, author = {Cleland, Elsa E. and M. D. Smith and Andelman, Sandy J. and Bowles, Christy and Carney, Karen M. and Horner-Devine, M. Claire and Drake, John M. and Emery, Sarah M. and Gramling, Joel M. and Vandermast, David B.} } @inbook {50663, title = {Internal regulation of nutrient uptake by relative growth rate and nutrient-use efficiency}, booktitle = {Ecological studies: nutrient acquisition by plants: an ecological perspective}, year = {2004}, note = {//??//LTER IV//ProCite field[6]: In}, month = {2004}, publisher = {Springer, Heidelberg}, organization = {Springer, Heidelberg}, abstract = {

Plants are observed to regulate their uptake of nutrients in elaborate patternsaccording to their environment of growth and their stage of development.Among the common patterns is that plants reduce their nutrient uptakecapacities (per mass of root,n, or of the whole plant,nplant) as nutrient concen-trations increase (Clements et al. 1979; Godwin and Blair 1991; Youssefi et al.1999; see Chap. 6, this Vol.). Similarly, changes in the shoot{\textquoteright}s environment,such as in CO2partial pressure, also induce changes in nutrient uptake rates(n). A number of questions arise {\textendash} for one, why should a {\textquoteleft}good{\textquoteright} such as nutri-ent acquisition ever be curtailed, or not expressed at a maximal rate? Onemust infer that downregulating the acquisition of a beneficial resource con-fers a net benefit in Darwinian fitness, for which most plants or their immedi-ate ancestors have been heavily selected. Admittedly, long-domesticatedplants may diverge from the fitness functions of wild plants (Gutschick 1987,1997, 1999; Jackson and Koch 1997). In some cases, the explanation lies at theimmediate physiological level, in that some nutrients in excess are toxic, suchas boron (Nable et al. 1990) and even phosphate (e.g., Romera et al. 1992).Nonetheless, such downregulation occurs even for nutrients that show noapparent toxicity in luxury consumption, such as nitrogen. Plant performancedoes not follow the guidelines espoused by the actress Mae West, {\textquotedblleft}Too muchof a good thing is wonderful{\textquotedblright}. Some experimental evidence shows that over-expression of nontoxic nutrient acquisition is deleterious to plant growth andfitness {\textendash} witness the stunting of supernodulating legumes (Carroll et al.1985), which can perhaps be attributed to excess diversion of photosynthateto N2fixation. Nonetheless, downregulation occurs even at modest, physiolog-ical nutrient content, most markedly in woody plants (Gessler et al. 1998).

}, keywords = {book, books, chapter, chapters, Phloem Loading ts, plant, growth rate, plant, nutrient uptake, plant, nutrient-use efficiency, Relative Growth Rate, report, Root Turnover, Shoot Ratio, Uptake Capacity}, doi = {10.1007/3-540-27675-0_4}, url = {files/bibliography/JRN00410.pdf}, author = {V. P. Gutschick and Pushnik, J. C.}, editor = {H. BassiriRad} } @conference {50664, title = {Impacts of livestock grazing in sagebrush ecosystems}, booktitle = {89th Annual Meeting, Ecological Society of America}, year = {2004}, month = {August 1-6, 2004}, pages = {Abstract p. 210}, address = {Portland, OR }, abstract = {Differential impacts of grazing by domestic livestock as a function of stocking rates (land area/animal numbers/time) on western rangelands have been recognized for decades. In the sagebrush steppe the general impacts of chronically excessive stocking rates are typically negative, long lasting, and usually complicated by concurrent episodic disturbances (such as drought, fire, and species introductions). There are numerous general theories on the role of large ungulates in shaping rangeland systems and, though domestication has altered some behaviors of their historic predecessors, inherent foraging behaviors of livestock are similar to other wild ungulates. Today, the issues surrounding grazing impacts by livestock revolve less around excessive uses and more about chronic direct and indirect impacts of preference, presence, and pattern of use. This review will acknowledge the well-recognized impacts of excessive use, describe associated impacts (such as landscape fragmentation, predator control, and encroaching or invasive species), and characterize the more pervasive direct and indirect impacts of managed grazing on sagebrush steppe rangelands.}, keywords = {impacts, livestock grazing, managed grazing, rangelands, sagebrush ecosystems, stocking rates}, author = {Kris Havstad and Vavra, M.} } @conference {50669, title = {An integrated framework for multi-objective inventory, assessment, and monitoring}, booktitle = {Sixth Symposium on the Natural Resources of the Chihuahuan Desert Region}, year = {2004}, month = {October 15, 2004}, pages = {28}, address = {Alpine, TX}, abstract = {Science-based land management requires quantification of ecosystem properties (inventory), the status of these properties relative to their potential (assessment), and changes in these properties over time (monitoring). Unique datasets are typically generated to address different management objectives, including livestock production, watershed conservation, wildlife habitat protection, military training, and other land uses and values. We describe an integrated framework for inventory, assessment, and monitoring. This framework is based on three components: (1) Ecological site descriptions (which are based on soil surveys) and the National Resource Inventory provide standardized, nationwide inventory data. These data, related information, and expert knowledge are used to generate a standardized, ecological site-specific reference for a qualitative assessment protocol, which is used to rapidly assess current status. (2) Selected measurements from a flexible, quantitative monitoring protocol are used to generate indicators that supplement the qualitative assessments. (3) These indicators are subsequently used to monitor changes in ecosystem function. More specific management objectives are addressed using additional indicators calculated from the basic measurements. Additional measurements included in the monitoring "toolbox" can also be included. In many cases, however, multiple management objectives can be addressed by monitoring a very few key properties, such as the amount and spatial distribution of bare ground and the cover of a few key species. This framework is designed to facilitate the integration of multi- and cross-scale approaches, including remote sensing, as they are developed.}, keywords = {assessment, ecosystem properties, integrated framework, inventory, land management, monitoring, multi-objective}, author = {Jeffrey E. Herrick and Alexander, R. and Bash, D. and Brandon T Bestelmeyer and Biggam, P. and Joel R. Brown and Kris Havstad and Andrea S. Laliberte and David P. Toledo and A.J. Tugel} } @article {50672, title = {Influence of vegetation cover and crust type on wind-blown sediment in a semi-arid climate}, journal = {Journal of Arid Environments}, volume = {58}, year = {2004}, note = {//USDA//NONE// Received and Entered 12/15/2005}, month = {2004}, pages = {167-179}, abstract = {This study determined the influence differing soil surface textures and vegetative covers haveon the magnitude of wind erosion in a semi-arid environment. The study was conducted fromMarch 2000 through late April 2000 on the Jornada Experimental Range approximately 37kmnorth of Las Cruces, New Mexico. Big Spring Number Eight (BSNE) samplers placed at ninelocations, collected particulates in suspension and saltation at heights of 5, 10, 20, 50, and100 cm from the following surfaces: loose sand, thick silty physical crust, flaky physical crust,weak desert pavement, and a forb/grass ground cover. BSNE samplers collected the largestamounts of sediment were collected in areas of loose sand and at sites directly downwind fromloose sand than sites containing heavy crusting, gravel, or a forb/grass cover. Differencesbetween sites with gravel surfaces and those with forb/grass cover were insignificant. Theseresults quantify the importance of surface cover as an agent towards reducing the extent ofwind erosion on semi-arid landscapes.{\textcopyright} 2003 Elsevier Ltd. All rights reserved.}, keywords = {aeolian processes, crust type, aeolian processes, vegetation effects, aeolian processes, wind erosion, aeolian processes, wind-transported dust, article, crusty type, journal, rangelands, saltation, vegetation cover, wind erosion}, author = {Joseph P. Hupy} } @conference {50685, title = {Implications of plant-fungal interactions: can microscale processes have macroscale impacts?}, booktitle = {Sixth Symposium on the Natural Resources of the Chihuahuan Desert Region}, year = {2004}, month = {October 25, 2004}, pages = {32}, address = {Alpine, TX}, abstract = {The roles microorganisms play in shaping desert plant communities have often been underestimated. Recent tools expanding our abilities to detect, identify, and monitor microbial inhabitants of plant tissues are providing new insights to amazingly complex systems. Microscale examination of Boutelouaeriopoda (black grama grass) and Atriplexcanescens (fourwing saltbush) has revealed diverse fungal communities living within individual plants. The compositions of these fungal communities are apparently dictated by multiple factors. We believe these internal fungi assist the plant with water and nutrient transport, drought tolerance, and defense against herbivores and pathogens. To explore thresholds of plant fitness that are defined by microbial communities, we transferred fungi inhabiting Boutelouaeriopoda, Atriplex canescens, and Sporobolus cryptandrus to eight, nonhost plant species. Dramatic, whole-plant differences in morphology, water potential, chlorophyll content, dates to maturity, seed production and marker gene profiles, and more between treated and untreated plants, were observed. In most cases, endophyte transfer at the cellular level produced astonishingly robust plants with greater reproductive potential than the untransformed counterparts. The dramatic changes observed in plants with altered microbial populations illustrate the propagation of cellular-level changes to whole-plant and progeny-scale impacts. We hypothesize that these transformed plants will continue to grow, reproduce, and disperse more rapidly than their native counterparts, propagating changes from the plant-microbe interface to ecologically significant scales. Broad-scale factors limiting this process are being explored.}, keywords = {black grama, desert plant communities, fourwing saltbush, macroscale impacts, microscale processes, plant-fungal interactions}, author = {M.E. Lucero and J.R. Barrow} } @article {50687, title = {The impact of a prescribed burn on introduced Lehmann lovegrass versus native vegetation in the northern Chihuahuan Desert}, journal = {Journal of Arid Environments}, volume = {57}, number = {3}, year = {2004}, note = {//USDA//LTER IV//entered 05/04/2004; updated 04/07/2009}, month = {2004}, pages = {297-310}, abstract = {

Prescribed burning has been suggested as a method to prevent shrub encroachment on desert grasslands. A concern for range managers is the prevalence of introduced African lovegrasses (Eragrostis spp.). These exotic grasses may compromise the effectiveness of fire as a range management tool in these areas due to their fire tolerance. In this study we examined the response of an established patch of Lehmann lovegrass to a prescribed burn. While Lehmann lovegrass was not adversely affected by the prescribed burn, all of the native grasses were compromised to some degree.

}, keywords = {article, articles, Bouteloua, fire, Eragrostis, fire, fire, Bouteloua, fire, Eragrostis, fire, grass, fire, Lehmann lovegrass, fire, prescribed burns, grassland, burning, grassland, fire, journal, journals, plant, invasive species, plant, non-native}, doi = {10.1016/S0140-1963(03)00109-5}, url = {files/bibliography/JRN00422.pdf}, author = {McGlone, Christopher M. and L. Huenneke} } @article {50705, title = {Insights to invasive species dynamics from desertification studies}, journal = {Weed Technology}, volume = {18}, year = {2004}, month = {August 1, 2004}, pages = {1221-1225}, abstract = {

The objective of this paper is to provide insights into exotic and native invasive species dynamics using a conceptual model developed from the long history of research on native woody plant invasion into perennial grasslands. We first describe our new conceptual model that focuses on landscape characteristics (spatial configuration and connectivity) interacting with environmental drivers and biotic processes across multiple scales. We then provide support for the model using a long-term dataset from southern New Mexico. Finally, we discuss new insights this model has to offer for understanding, predicting, and managing exotic invasive species dynamics.

}, keywords = {conceptual model, exotic, invasive species, managing, native, perennial grasslands, predicting, woody plant invasion}, doi = {10.1614/0890-037X(2004)018[1221:ITISDF]2.0.CO;2}, url = {files/bibliography/JRN00409.pdf}, author = {Debra C. Peters and Jin Yao and Kris Havstad} } @conference {50703, title = {Introducing the International Long-Term Ecological Research (ILTER) network}, booktitle = {LAND Open Science Conference}, year = {2004}, month = {December 2, 2004}, pages = {62}, address = {Morelia, Mexico}, abstract = {Long-term, broad-scope research is important for revealing trends that cannot be detected with traditional short-term, small-scale research. Global scientific interest in developing networks of long-term ecological research programs is expanding rapidly, acknowledging the utility of this model for research in assessing and resolving complex environmental issues. Through the International Long-Term Ecological Research Network (ILTER), investigators around the globe exchange expertise, develop and share knowledge and information resources and research methods, thus integrating their research and placing it in a global context. This poster will offer an introduction to the methods used to develop and grow the ILTER Network, address the impact of global-scale science, and inspire discussion about these topics.}, author = {Debra C. Peters and Sprott, P. and French, C.} } @article {JRN54974, title = {Integrating two remote sensing-based hydrological models and MODIS data to improve water supply forecasts in the Rio Grande Basin}, journal = {Hydrology: Science \& Practice for the 21st Century}, volume = {1}, year = {2004}, pages = {453-457}, chapter = {453}, abstract = {

Remotely-sensed data can be used with modern hydrological models to provide effective water supply forecasts and to evaluate water resources management options.

}, url = {files/bibliography/Rango2004-01.pdf}, author = {A. Rango and E. Gomez-Landesa and M. Bleiweiss and D. DeWalle and G. Kite and J. Martinec and Kris Havstad} } @proceedings {50712, title = {Integrating two remote-sensing-based hydrological models and MODIS data to improve water supply forecasts in the Rio Grande Basin}, volume = {I}, year = {2004}, month = {July 12-16, 2004}, pages = {453-457}, address = {Imperial College, London, UK}, abstract = {Remotely sensed data can be used with modern hydrological models to provide effective water supply forecasts and to evaluate water resource management options. MODIS, on both NASA TERRA and AQUA satellites, is the likely optimum sensor for snow mapping because it has a best resolution of 250 m (two bands), it passes over daily, it is free for downloading, and it provides a logical transition from 1-km NOAA-AVHRR data. Its worth for snow mapping has been proven both in the Rocky Mountains of the U.S. and the Pyrenees of Spain. Still, research to solve automation and operational problems is ongoing, including corrections for the {\textquoteright}bow-tie{\textquoteright} effect, mapping in shaded and heavily vegetated areas, and using bidirectional reflectance distribution functions to retrieve snow albedo. As the remote sensing improvements are made, the data are used in the upper Rio Grande basin for improvement of the snowmelt forecasting system. Remote snow water equivalent site data is acquired through the Natural Resources Conservation Service SNOTEL system employing meteor-burst relay. These data can be used for early season (November-December-January), volumetric forecasts that increase water management flexibility. The MODIS-derived snow cover data are input to the Snowmelt Runoff Model (SRM) for generating daily streamflow forecasts over the entire melt season. Because snowmelt runoff is not significant throughout the entire basin, SRM outflow from snowmelt basins is linked to the Semi-Distributed, Land-Use-Based Runoff Process (SLURP) model as an input. SLURP is a comprehensive, distributed model now operating on the entire basin to assist in water management decision making today and to evaluate future scenarios for improving long-range planning. SLURP is also used for remote sensing inputs to establish current land cover throughout the basin and to derive the Leaf Area Index for use in evapotranspiration algorithms. Examples of forecasts for 2001-2004 in the upper Rio Grande basin are presented.}, keywords = {hydrological models, MODIS data, remote sensing, Rio Grande Basin, water supply forecasts}, url = {/files/bibliography/04-063Proc.pdf}, author = {A. Rango and E. Gomez-Landesa and M. Bleiweiss and D. DeWalle and G. Kite and J. Martinec and Kris Havstad} } @conference {50713, title = {In vitro mass clonal propagation and hyperhydricity reversal of four-wing saltbush (Atriplex canescens (Pursh) Nutt.)}, booktitle = {2004 World Congress on In Vitro Biology}, year = {2004}, month = {May 2004}, address = {San Francisco, CA}, abstract = {A successful, in vitro mass propagation system for cloning four-wing saltbush, Atriplex canescens (Pursh) Nutt., was achieved. In vitro propagated shoots of A. canescens showed severe symptoms of hyperhydricity, a frequent physiological problem reported in miro-propagation of A. canescens and other plant species. Hyperhydricity was exacerbated when cultured in airtight culture vessels and high ammonium concentraqtions in common media formulations and drastically reduced the quality of in vitro cultures. Hyperhydric shoots reverted to normal shoots by culturing on modified Murashige and Skoog basal medium and using larger culture vessels with vented closures. Resulting normal shoots significantly improved all aspects of micro-propagation. Shoots were rooted in vitro by supplementing the culture medium with 2.45 uM of indolebutyric acid (IBA). Plants were successfully reestablished in soil transplanted and surviving in native sites.}, author = {Reyes, I. and Hubstenberger, J. and J.R. Barrow} } @mastersthesis {50729, title = {An investigation into the effects of the transition from grassland to shrubland on hydrological connectivity in the Jornada Basin, New Mexico}, year = {2004}, note = {//NMSU//LTER IV//ProCite field[12]: In File (06/24/2005)}, month = {2004}, pages = {88}, school = {University of London}, type = {M.S. Dissertationpp}, address = {King{\textquoteright}s College London}, abstract = {The effect of the transition from grassland to shrubland on hydrological connectivity is investigated over a semi-arid rangeland. A cellular model is developed to simulate hydrological connectivity for individual rain events. The model is based upon the probability of transfer of runoff to downslope cells. Simulations were based upon surveyed elevation data over 30 x 30m grassland and shrubland plots. Results show that the transition from grassland to shrubland causes a profound increase in hydrological connectivity, attributed to interactions between surface characteristics that propagate flow to the plot outlet, though primarily to the shrubland associated microtopography which concentrates runoff.}, keywords = {dissertation, dissertations, hydrology, grassland, hydrology, model, hydrology, runoff, hydrology, runon, hydrology, shrubland, model, hydrology, theses, thesis}, author = {Turnbull, Laura} } @article {50760, title = {Impact of filter paper on fluorescence measurements of buffered saline filtrates}, journal = {Talanta}, volume = {59}, number = {3}, year = {2003}, month = {March 1, 2003}, pages = {601-604}, abstract = {A fluorescent contaminate has been observed in phosphate buffered saline filtrates using a commercially available filter paper. The fluorescence of this material was observed to exhibit a maximum signal at 440.0 nm when excited at 365 nm. This could have significant implications in the design and implementation of sample processing protocols when using fluorescence detection of trace components.}, url = {/files/bibliography/03-016.pdf}, author = {T.L. Danielson and G.D. Rayson and D.M. Anderson and Richard E. Estell and E.L. Fredrickson and Kris Havstad and Green, B.S.} } @article {50773, title = {Influence of an exotic species, acroptilon repens (L.) DC. on the initial survival and growth of native grasses}, journal = {Plant Ecology}, volume = {166}, number = {2}, year = {2003}, month = {September 1, 200}, pages = {157-166}, abstract = {

Our objective was to evaluate the effects of an invasive perennial forb, Acroptilon repens (Russian knapweed) on seed germination and seedling survival of four native grass species that are important in semiarid grasslands of North America. Greenhouse experiments and field studies conducted at three sites in Colorado were used to examine the response by four perennial grasses: Bouteloua gracilis, Koelaria cristata, Sporobolus cryptandrus, and Agropyon smithii to A. repens. In the greenhouse, seeds of each species were sown in pots that contained either live A. repens roots, litter on the soil surface, or both roots and litter. Field transects were placed inside stands of A. repens with adjacent control transects in the surrounding grass-dominated community. Germination and initial survival were decreased by the presence of A. repens roots for K. cristata (35\%), B. gracilis (31\%), and S. cryptandrus (44\%) in the greenhouse, and 57, 32, and d36\%, respectively, in the field. Root weight was decreased by the presence of A. repens roots for both B. gracilis and K. cristata by more than 55\% in the greenhouse. A. smithii survival and growth was unaffected by A. repens in either the greenhouse or the field. These species-specific responses to the presence of A. repens may explain, at least in part, differences in susceptibility and recovery of sites with different native grass species composition.

}, doi = {10.1023/A:1023221024593}, url = {/files/bibliography/03-011.pdf}, author = {Grant, D.W. and Debra C. Peters and Beck, K.G. and Fraleigh, H.D.} } @article {50811, title = {Improved satellite snow mapping, snowmelt runoff forecasting, and climate change in simulations in the upper Rio Grande basin}, journal = {World Resource Review}, volume = {15}, number = {1}, year = {2003}, month = {April 1, 2003}, pages = {25-41}, abstract = {The knowledge of snow water resources is a major concern in high elevation basins where snowmelt streamflow can make a significant contribution to the total discharge. This information is especially useful for irrigation, hydropower and water supply management. In this paper, we present a system for snow water resources evaluation, based on satellite data, that generates three products; snow cover distribution with altitude, snowmelt runoff forecasts, and simulations of the expected future snowmelt seasons using the climate change scenarios indicated by international agencies. The new generation of satellites is providing scenes of the earth with increasing quality, more spectral bands, and better spatial resolution. To take advantage of these improvements, it has been necessary to solve new problems associated with the design of the new instruments, such as the so-called {\textquestiondown}Bowtie Effect{\textquestiondown} of the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument. The system developed is being currently applied to the upper Rio Grande Basin in the Colorado Rocky Mountains and to several basins in the Spanish Pyrenees. As an example, a 6-month, daily hydrograph was forecasted for the Upper Rio Grande at Del Norte, CO, for 2001 that was 14.4\% different from the observed flow and had an R2=0.768. Furthermore, hydrographs were produced under conditions of changing climate progressively through the 21st century.}, url = {/files/bibliography/03-002.pdf}, author = {A. Rango and E. Gomez-Landesa and M. Bleiweiss and Kris Havstad and Tanksley, K.} } @article {50819, title = {Investigating landscape instability in the northern Chihuahuan Desert at multiple scales using 137 Cesium}, journal = {Journal of Arid Environments}, volume = {55}, year = {2003}, note = {//?//LTER IV//}, month = {2003}, pages = {737-746}, keywords = {article, articles, Chihuahuan Desert, instability, landscape, isotopes, 137Cesium, journal, journals, landscape, evolution, landscape, instability}, author = {Jerry Ritchie and Jeffrey E. Herrick and Ritchie, C.A.} } @article {JRN54951, title = {Imaging and characterizing fresh and metamorphosed snow crystals with low temperature scanning electron microscopy}, journal = {Recent Research Developments in Geophysics}, volume = {5}, year = {2003}, month = {10/2003}, pages = {21-55}, chapter = {21}, abstract = {

A technique known as low temperature scanning electron microscopy (SEM) has been used to image precipitating and metamorphosed snow crystals, as well as glacial ice. This review summarizes the methods used to collect, transport and store samples of snow and ice and illustrates the basic types of snow crystals that occur in nature along with the changes they undergo in snowpack. In addition, the study illustrates firn and glacial ice which were also sampled and examined with the low temperature SEM. The results illustrate the ease and the resolution with which samples of snow and ice can be observed, studied and photographed. Until recently, studies of snow and ice were largely restricted to a hand lens or the light microscopy (LM); the laboratory and the instrumentation had to be cooled to temperatures below freezing, frequently near a collection site. This expensive and inconvenient requirement is not necessary for observations using the low temperature SEM. Alternatively, samples are easily collected in the field and have been shipped to the electron microscopy laboratory by common air carrier from distances as far away as 8,000 km. Delicate specimens of snow crystals and ice grains survive the shipment procedures and have been stored for as long as 3 years without undergoing any structural changes. Furthermore, the tilting stage of the SEM permits photographs to be recorded that contain the information necessary for three-dimensional imaging. As a result, visualization of the true shapes of snowflakes, snow crystals, snow clusters, ice grains and their interspersed air spaces is easily achieved.

}, keywords = {microscopy, scanning, snow crystals}, url = {files/bibliography/Rango2003-04.pdf}, author = {W.P. Wergin and A. Rango and J. Foster and E. G. Josberger and E. R. Erbe and C.D. Pooley} } @article {50843, title = {Inverted clast stratigraphy in an eolian archaeological environment}, journal = {Geoarchaeology}, volume = {17}, year = {2002}, note = {//?//LTER ?//}, month = {2002}, pages = {665-687}, abstract = {

Understanding the geomorphic history of eolian basins is important in interpreting the archaeological record and human responses to past environments. One hundred forty soil profiles were excavated and described in southern New Mexico and West Texas. Seven major late Quaternary stratigraphic units were found: La Mesa, eolian Jornada (I, II), eolian Isaacks{\textquoteright} Ranch, eolian Organ (I, II, and III), Historical Blowsand, and the playa deposits of Petts Tank and Lake Tank. Each unit represents a period of landscape instability, eolian erosion, and concurrent deposition, followed by landscape stability and soil formation. Eolian erosion can form local surficial lag deposits if materials larger than the competence of the wind are present. However, erosional processes alone cannot explain the presence of older clasts at the surface with intact, younger deposits underneath. We propose a combination of processes: deflation in eolian windows, followed by lateral movement of clasts over areas that have not been deflated. The effects of these processes on artifact stratigraphy and archaeological interpretations could be significant.

}, keywords = {article, articles, eolian, journal, journals, stratigraphy, clast}, doi = {10.1002/gea.10037}, url = {files/bibliography/JRN00360.pdf}, author = {B. J. Buck and Kipp, J. and Curtis H. Monger} } @proceedings {50845, title = {The importance of early morning local overpass times for BRDF retrieval, modeling of spectral reflectance and fAPAR estimation}, volume = {6}, year = {2002}, month = {June 24-28, 2002}, pages = {2264-2266}, address = {Toronto, Canada}, abstract = {A High Resolution Picture Transmission (HRPT)/Local Area Coverage (LAC) data set collected and processed for the NASA Earth Observing System Prototype Validation Exercise (PROVE) campaign for the period May 10-June 3, 1997, was used to retrieve estimates of the bidirectional reflectance distribution function (BRDF) over central-southern New Mexico and parts of Chihuahua, Mexico, by inverting a linear, semi-empirical, kernel-driven model (LISK) composed of isotropic, geometric-optical and volume scattering kernels (unity, LiSparse-MODIS and Ross-Thin, respectively). The surface reflectance estimates used to adjust the model were derived from 17 orbits over a 25-day period at the end of the dry season. The inverse matrix which provides the solution to the inversion problem was used to obtain noise inflation factors (or "weights of determination") for reflectance modeled at viewing angles in the range +/-60 deg for solar zenith angles of f0 deg, 30 deg, and 60 deg in the solar principal plane. A reflectance image was modeled with a view zenith angle of 45 deg and an SZA of 60 deg in the principal plane, suggested in the literature as optimal for retrieval of the fraction of fAPAR. Noise was found to be important (noise amplification factors exceeded unity by a large margin) where observations from early morning overpasses were missing as a result of cloud and cloud-shadow contamination. In these cases, BRDF model parameters and derived reflectance values are unlikely to be reliable, necessitating the injection of a priori knowledge into the model inversion procedure.}, url = {/files/bibliography/02-007.pdf}, author = {M. Chopping and A. Rango and E. Gomez-Landesa} } @article {50847, title = {Improved semiarid community type differentiation with the NOAA AVHRR via exploitation of the directional signal}, journal = {IEEE Transactions on Geoscience and Remote Sensing}, volume = {40}, number = {5}, year = {2002}, note = {Entered by Beltsville January 1, 2002}, month = {May 1, 2002}, pages = {1132-1149}, abstract = {

Mapping semi-arid vegetation types at the community level is extremely difficult for optical sensors with large ground footprints such as the National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR). Attempts to use solar wavelength AVHRR data in community type differentiation have often resulted in unacceptable classification errors which are usually attributed to noise from topographic and soil background variations, inaccurate reflectance retrieval and poor registration. One source of variation which is rarely accounted for adequately is the directional signal resulting from the combined effects of the surface bidirectional reflectance distribution function (BRDF) and the variation of viewing and illumination geometry as a function of scan angle, season, latitude and orbital overpass time. In this study, a linear semiempirical kernel-driven (LiSK) BRDF model is used to examine the utility of the directional signal in community and cover type differentiation over discontinuous but statistically homogeneous semi-arid canopies in Inner Mongolia Autonomous Region (IMAR), China, and New Mexico (NM), USA. This research shows that the directional signal resulting from the physical structure of the canopy-soil complex can be retrieved to provide information which is highly complementary to that obtained in the spectral domain.

}, url = {http://ieeexplore.ieee.org/iel5/36/21784/01010900.pdf?isnumber=21784\&prod=JNL\&arnumber=1010900\&arSt=1132\&ared=1149\&arAuthor=Chopping\%2C+M.J.\%3B+Rango\%2C+A.\%3B+Ritchie\%2C+J.C.}, author = {M. Chopping and A. Rango and Jerry Ritchie} } @conference {50869, title = {Improvements in snow mapping of the Rio Grande Basin using MODIS data}, booktitle = {American Geophysical Union, 2002 Fall Meeting}, volume = {83}, number = {47}, year = {2002}, month = {November 19, 200}, pages = {F540}, address = {San Francisco, CA}, abstract = {Snow-covered area data is valuable for assessing watershed condition. Additionally, it is being used as an input for the Snowmelt Runoff Model (SRM) which provides simulations and forecasts of a basin{\textquoteright}s daily streamflow. A visible and a near infrared channels of the Moderate Resolution Imaging Spectroradiometer (MODIS) are being used to generate snow maps, replacing the traditional Advanced Very High Resolution Radiometer (AVHRR) data and, therefore, improving the spatial resolution of the snow maps from 1 km to 250 m. In order to implement the MODIS data, a geometric correction algorithm was developed to remove the so-called Bowtie Effect from the MODIS scenes. Radiances from pixels located on shaded slopes of the basin are strongly diminished because the two channels used in this method receive radiation from the solar reflective region of the spectrum. To correct this problem, an algorithm was developed to simulate the shaded areas on a Digital Elevation Model (DEM). This effect was found to be dependent on the altitude of the pixel, so an empirical, second-order polynomial was applied. In order to make the snow mapping system as automated as possible, new methods were studied to retrieve snow albedo using bidrectional reflectance distribution functions (BRDF). Albedo retrieval can also be used as a criterium to infer the start of the snowmelt season, due to the decrease in reflectance of the snowpack as it ages.}, author = {E. Gomez-Landesa and A. Rango} } @proceedings {50887, title = {Integration of soil indicators into multi-attribute rangeland monitoring and assessment systems}, volume = {Report QNRM02143}, year = {2002}, month = {August 1-6, 1999}, publisher = {Queensland Department of Natural Resources and Mines, Australia 2002}, address = {Brisbane, Australia}, abstract = {Rangeland health and soil quality are frequently defined in terms of the capacity of the land to conserve soil and water resources, cycle nutrients and support productive plant communities. Rangeland monitoring programs in most countries have traditionally focused, almost exclusively, on plant community composition. An implicit assumption is that other properties and processes are correlated with vegetation, so measurements are unnecessary. In many cases, however, soil degradation or improvement can occur in the absence of easily detectable vegetation changes until a threshold is crossed resulting in dramatic and frequently irreversible changes in plant community composition. We suggest that easily-measured soil properties can serve as early-warning indicators of potential transitions between vegetation states in rangeland ecosystems. These indicators and associated vegetation measurements are by no means universal. Both the selections of quantitative indicators and the identification of appropriate monitoring points depend on monitoring objectives and resource availability. Rapid, qualitative indicators can aid in the design of a quantitative monitoring program. They can also be applied together with quantitative indicators to aid interpretation. We describe how quantitative and qualitative soil and vegetation indicators can be used together to monitor rangeland health.}, keywords = {assessment, monitoring, rangeland health, soil and water conservation, soil quality, thresholds}, isbn = {0 7345 2668 7}, url = {/files/bibliography/02-097.pdf}, author = {Jeffrey E. Herrick and Kris Havstad}, editor = {Lawrence, P.A. and Robinson, J.} } @conference {50923, title = {Introduction and overview: approaches to addressing landscape-scale problems in ecology}, booktitle = {87th Annual Meeting, Ecological Society of America}, year = {2002}, month = {August 4-9, 2002}, pages = {41}, address = {Tucson, AZ}, abstract = {This talk provides an introduction to the symposium that will address tradeoffs and consequences of using alternative scaling approaches to deal with timely and critical ecological issues. Wildlife conservation, patterns and dynamics in carbon sequestration, loss of biodiversity, spread of invasive species, and atmosphere-biosphere interactions are issues that require an explicit consideration of spatial and temporal scaling at the landscape level. We present three major approaches to addressing these types of ecological problems that vary in their complexity and degree of spatial interactions. Each approach is discussed in terms of its strengths and weaknesses. Examples of the types of questions most suited to each approach are given. Each core talk covering the major scaling approaches is co-authored by a team of experts representing each of the following disciplines: vegetation dynamics, wildlife conservation, and carbon and soil water dynamics. We also present several highly visible and important case studies to illustrate the connections and relatedness among approaches and disciplines. We demonstrate the relevance of these approaches to addressing landscape-scale problems both by scaling information up from plots and by scaling down from coarse regional data. Although it is widely recognized that scaling is an important issue, there have been few attempts to provide guidance in selection and use of different approaches. This symposium provides this synthetic overview.}, author = {Debra C. Peters and D.L. Urban and Jeffrey E. Herrick} } @conference {50927, title = {Introduction: Approaches to scaling information from plots or regions to landscapes}, booktitle = {US-International Association for Landscape Ecology}, year = {2002}, month = {April 23-26, 200}, pages = {81}, address = {Lincoln, NE}, abstract = {This talk provides an introduction to the symposium that will address the tradeoffs and consequences of using alternative scaling approaches to dealing with critical and timely ecological issues. Three major approaches will be described that vary in their complexity and degree of spatial interactions: (1) nonspatial, (2) spatially implicit, and (3) spatially interactive. Each approach will be introduced in terms of its strengths and weaknesses. Examples of the types of questions most suited to each approach will also be given. Each talk will be co-authored by representatives of the following disciplines: vegetation dynamics, wildlife conservation, or carbon and soil water dynamics. Case studies will be used to illustrate the connections and relatedness among approaches and disciplines. The relevance of these approaches to addressing landscape-scale problems will be addressed both by scaling information up from plots and by scaling down from coarse regional data. Although it is widely recognized that scaling is an important issue, there have been few synthetic attempts to provide guidance in selection and use of different types of approaches. This synthetic overview will be provided as part of our symposium.}, author = {Debra C. Peters and Durban, D.L.} } @proceedings {50928, title = {Integrating ecological data: tools and techniques}, volume = {Volume VII, Information Systems Development II}, year = {2002}, note = {//NONE//LTER IV//ProCite field[6]: In}, month = {July 14-18, 2002}, pages = {396-401}, publisher = {International Institute of Informatics and Systemics}, address = {Orlando, FL}, abstract = {

Integration of data is critical to achieving new levels of understanding of ecological systems and processes. Typically, data integration is achieved only through a painstaking manual process that rules out large-scale integration. We believe that many of the techniques related to uncertain reasoning (fuzzy logic, Baysian networks, and evolutionary algorithms) and data mining might be usefully applied to ecological data integration. Here we present two case studies. One characterizes a traditional approach to integration. The second focuses on using software system integration to integrate geospatial and research data, along with providing data discovery services. We discuss those case studies where advanced techniques might prove useful and where modifications are needed to support scientific research.

}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, data management, also SEE , ecoinformatics, SEE , information management, also SEE , information management, data integration, information management, data mining, information management, ecoinformatics, information management, GIS, information management, proceeding, proceedings}, isbn = {980-07-8150-1}, url = {files/bibliography/JRN00359.pdf}, author = {John Porter and Ken Ramsey}, editor = {Callaos, Nagib and John Porter and Rishe , Naphtali (eds.)} } @conference {50931, title = {Implementation of a remote sensing-snowmelt runoff forecasting system in the Rio Grande Basin}, booktitle = {EOS Transactions, American Geophysical Union}, volume = {83}, number = {47}, year = {2002}, month = {November 19, 200}, pages = {F540}, address = {San Francisco, CA}, abstract = {

Information on snow water resources is a major concern in river basins where the snowmelt runoff can be a significant contributor to total discharge, even in basins such as the Rio Grande where desert makes up much of the downstream area. Snow resource information is especially useful in the Rio Grande for irrigation, hydropower, and water supply management. The system, being developed for the high elevation portions of the Rio Grande Basin, makes use of satellite snow cover data as well as SNOTEL data from remote, ground-based instrumentation. Several problems in using the new MODIS satellite data have been addressed in order to input it into the modeling system in the basin, including the Bowtie Effect and topographic shadowing (see Gomez-Landesa and Rango, 2002). The snow distribution in March-May in snowmelt headwater basins of the Rio Grande is input into the Snowmelt Runoff Model (SRM) to generate forecasts of daily flows. To allow forecasts earlier in the hydrologic year, the SNOTEL data are relied upon until the snowmelt is underway (see DeWalle et al., 2002) and the satellite data play a larger role. The outflow generated by SRM from the snowmelt basins is then used as input to the SLURP model which is used to provide discharge for the entire basin, as well as for tributaries only affected by rainfall. The utilization of SRM in the snow-fed basins also allows generation of climate-change-affected hydrographs for individual tributaries. The Jemez River Basin (New Mexico), a designated wild river, is being used for validation of both snow cover maps and discharge forecasts, whereas the upper Rio Grande Basin (Colorado) has been selected for evaluation of the climate change scenarios.

}, author = {A. Rango and E. Gomez-Landesa and Kris Havstad and M. Bleiweiss and Tanksley, K. and D. DeWalle and G. Kite} } @inbook {50936, title = {Inorganic carbon and the global carbon cycle}, booktitle = {Encyclopedia of Soil Science}, year = {2002}, note = {//??//LTER IV//ProCite field[6]: In}, month = {2002}, pages = {706-708}, publisher = {Marcel Dekker Inc.}, organization = {Marcel Dekker Inc.}, address = {New York, NY}, abstract = {

Changes in the quantity of carbon (C) in vegetation and soils play a major role in determining short- and long-term fluctuations in the concentration of carbon dioxide (CO2) in earth{\textquoteright}s atmosphere. Human activities, such as the irrigation of agricultural soils in arid regions, can alter the accumulation of pedogenic carbonate in soils. For comparative purposes, biogeochemists calculate the mean residence time (MRT). Although the amount of pedogenic carbonate in world soils is quite large, this pool of C is relatively sluggish. The long MRT of the pedogenic carbonate pool ensures that it will not become a major sink or source of atmospheric CO2 over the next several centuries.

}, keywords = {book, books, carbon,soil, chapter, chapters, report, reports}, author = {W. H. Schlesinger}, editor = {R. (ed.) Lal} } @article {50951, title = {Irregular snow crystals: structural features as revealed by low temperature scanning electron microscopy}, journal = {Scanning}, volume = {24}, number = {5}, year = {2002}, month = {September 1, 200}, pages = {247-256}, abstract = {

For nearly 50 years, investigators using light microscopy have vaguely alluded to a unique type of snow crystal known as an irregular snow crystal. However, the limited resolution and depth-of-field of the light microscope has prevented investigators from characterizing these crystals. In this study, a field-emission scanning electron microscope equipped with a cold stage was used to document the structural features, physical associations and atmospheric metamorphosis of irregular snow crystals. The crystals appear as irregular hexagons measuring 69 to 90 um across when viewed from the a-axis. Their length (c-axis) rarely exceeds the diameter. The irregular crystals are occasionally found as secondary particles on other larger forms of snow crystals; however, they most frequently occur in aggregates consisting of more than 100 irregular crystals. In the aggregates, the irregular crystals have their axes oriented parallel to one another and collectively tend to form columnar structures. Occasionally, these columnar structures exhibit rounded faces along one side, suggesting atmospheric metamorphoses during formation and descent. In extreme cases of metamorphoses, the aggregates would be difficult to distinguish from graupel. Frost, consisting of irregular crystals, has also been encountered suggesting atmospheric conditions that favor their growth can also occur terrestrially.

}, url = {/files/bibliography/02-075.pdf}, author = {W.P. Wergin and A. Rango and J. Foster and E. R. Erbe and C.D. Pooley} } @article {50958, title = {Intensity of intra- and interspecific competition in coexisting shortgrass species}, journal = {Journal of Ecology}, volume = {89}, year = {2001}, month = {February 1, 2001}, pages = {40-47}, abstract = {

A previous study indicated photosynthesis of Bouteloua gracilis and Buchloe dactylaides has a similar response to temperature, achieving their maximum at high temperatures. Together, photosynthesis response and phenology determine no temporal segregation in growth for these 2 grasses. To study competitive abilities, we performed 2 experiments that combined both species to compare intra- and interspecific competition. One experiment was planted in a small homogeneous area and ran for 3 years; the other occupied an area 9-times larger and lasted 2 years. In each, we planted target plants of both species in a honeycomb design to get a combination of species, to control plant size and neighborhood asymmetries at the start of the experiment, and to represent field conditions. Steel cylinders placed around half the target plants reduced belowground competition. Plant biomass and seed production of plants growing inside the cylinders (reduced dcompetition) were higher than target plants growing in competition. In neither experiment was relative growth rate affected by competition in the last year. There was no difference between the two species in intra- and interspecific relative competition intensity (calculated with biomass); seed production was more variable than biomass. In some years, intra- and interspecific competition equally reduced seed production; in others, the interspecific competition effect was more intense. Competition theory predicts intraspecific competition must be greater than interspecific for 2 species with similar requirements to achieve coexistence. Results suggest intense competition between these 2 species with similar environmental requirements and, in general, these species are not affected differentially by intra- and interspecific competition.

}, doi = {10.1046/j.1365-2745.2001.00523.x}, url = {files/bibliography/01-001.pdf}, author = {M. Aguiar and W. K. Lauenroth and Debra C. Peters} } @article {50964, title = {Imaging spectroscopy measures desertification in United States and Argentina}, journal = {Eos, Transactions, American Geophysical Union}, volume = {82}, number = {49}, year = {2001}, note = {//USDA//LTER IV//}, month = {2001}, pages = {601,605-606}, abstract = {

Remote sensing-based monitoring of land degradation and desertification requires measurements of both live and senescent vegetation extent and condition, as well as bare soil areas, over large regions. Imaging spectroscopy (hyperspectral imaging) with full solar-reflected spectral signatures is now making these measurements from airborne and space-based observations. Using recent AVIRIS data sets, studies of dryland ecosystems, land degradation, and desertification are underway in the southwestern United States and central Argentina. The goals of this effort are to improve understanding of the physical and biogeochemical impacts of human activities as well as the role of climate variability in these regions. An essential element of these studies is determination of the spatial pattern and aboveground biomass distribution of live and senescent vegetation and bare soils from imaging spectroscopy data. One of the regions studied includes the Jornada Long-term Ecological Research (LTER) site, located in southern New Mexico. Images provide the observations required for quantitative studies of land degradation in these spatially complex dryland ecosystems. (1) Observations in the visible, near-infrared, and shortwave-infrared (0.4-2.5 {\`\i}m) provide a means to identify the presence of live and senescent vegetation canopies. Properties of these canopies derived from the spectroscopic measurements include leaf area index, water content, and aboveground live and senescent biomass. (2) Spectroscopic observations allow accurate measurement of vegetation and bare soil extent at the sub-pixel scale, resulting in continuous spatial fields of these surface properties. This information opens the door for new quantitative studies of ecosystem responses to land use and climate variability dryland regions. In addition to the quantification of biomass in the transition between grassland and shrubland, imaging spectroscopy also depicts varying surface conditions that represent important biogeochemical changes occurring in the region. These studies indicate that nutrient and carbon stocks are aggregated spatially in the transition zone, more so than in the grassland areas but less to than in the shrubland systems. Thus, the spatial patterning of live vegetation and surface litter is correlated with sub-surface processing of biologically important nutrients. A second region studied is a dryland region of central Argentina, where heavy grazing has resulted in another form of desertification. Spectroscopic analysis of AVIRIS data indicates areas of land degradation characterized by patterns of vegetation change previously described in Australian rangelands.

}, keywords = {article, articles, desertification, biogeochemistry, desertification, grassland, desertification, organic carbon, desertification, remote sensing, desertification, shrubland, desertification, soil nutrients, desertification, vegetation, journal, journals, remote sensing, AVIRIS, remote sensing, desertification, remote sensing, ecosystem health, remote sensing, EOS, remote sensing, grassland, remote sensing, ground reflectance, remote sensing, Hyperion, remote sensing, hyperspectral imaging, remote sensing, imaging spectroscopy, remote sensing, plant biomass, remote sensing, plant communities, remote sensing, shrub cover, remote sensing, soils, remote sensing, vegetation}, doi = {10.1029/01EO00346}, url = {files/bibliography/JRN00333.pdf}, author = {G.P. Asner and Green, Robert O.} } @conference {50970, title = {An integrated approach to managing landscape pattern and dynamics in southern New Mexico}, booktitle = {16th Annual Symposium, US-International Association for Landscape Ecology Meeting}, year = {2001}, month = {April 25-29, 200}, pages = {29}, address = {Tempe, AZ}, abstract = {The ecological site concept of USDA Natural Resource Conservation Service provides a hierarchical framework for classifying and distinguishing landscape units differing in the processes that determine plant and animal community dynamics within units and interactions among units. Ecological sites are based upon important differences in landscape position and inherent soil properties as defined by the responses of dominant plant species to variation in climate and management. Dominant plants, in turn, regulate several ecosystem attributes, including dynamic soil properties. State-and-transition models represent theories about the positive feedback between plants and ecosystems and the causes of irreversible changes in plant and animal composition. An understanding of these causes is needed to avoid ecosystem degradation, to fairly evaluate and manage instances of degradation, and to promote remediation. Here, we describe our ongoing efforts to improve the ecological site classification system for the Chihuahuan Desert of southern New Mexico by integrating current approaches to community and landscape ecology with the historical perspective and practical experiences of land managers and ranchers. Our approach emphasizes an increased understanding of patterns of dispersal, establishment, and growth of dominant plants along landscape and climatic gradients.}, author = {Brandon T Bestelmeyer and Joel R. Brown and Kris Havstad and Alexander, R. and Chavez, G. and Jeffrey E. Herrick} } @article {50976, title = {Introduction}, journal = {CATENA}, volume = {44}, year = {2001}, month = {May 18, 2001}, pages = {25-26}, abstract = {

The note serves as an introduction to a peer-reviewed set of papers which were inspired by and resulted from initiatives started at the workshop on soil aggregation in semi-arid and arid lands held in Las Cruces, NM on 8-10 May 1997. The two main objectives of the meeting were (1) to discuss and review soil aggregation processes in dry semi-natural areas and (2) to identify and evaluate methods for assessing soil aggregation in arid ecosystems.

}, url = {/files/bibliography/01-017.pdf}, author = {Cammeraat, E.L. and Jeffrey E. Herrick} } @article {50977, title = {Isotopic discrimination during long-term decomposition in an arid land ecosystem}, journal = {Soil Biology and Biochemistry}, volume = {33}, year = {2001}, note = {//USDA//LTER IV//}, month = {2001}, pages = {41-51}, abstract = {

Discrimination in carbon and nitrogen isotopes of decomposing plant litter in the northern Chihuahuan Desert was determined for a 5-year period. Factors influencing isotopic change were assessed from inter-species comparisons of litter chemistry, mass loss patterns, and isotope values of associated soil. Average delta15N litter values of buried roots increased 1.2 and 2.6{\textperthousand} for Big Blue Stem (Schizachyrium gerardi, grass) and Varital (Drypetes glauca, hardwood) during the study, respectively. Small but inconsistent variations were observed for Slash Pine (Pinus elliotii, conifer) roots. Average delta15N values of wooden dowels from Ramin (Gonystlylus bancanus, hardwood) increased ca. 2.0{\textperthousand} during years 1{\textendash}4, and then decreased slightly during year 5. Changes in delta15N litter were independent of N content, and may reflect microbial fractionation or preferential retention of 15N enriched substrates. Surprisingly, there was no clear relationship between litter N dynamics and C/N ratios. There were no discernable changes in delta13C litter values for Gonystlylus bancanus and Pinus elliotii. Average delta13C litter values for Schizachyrium gerardi decreased ~2.0{\textperthousand} during years 0{\textendash}2 and then increased slightly. In contrast, average delta13C litter values for Drypetes glauca increased ~0.5{\textperthousand} from years 0{\textendash}1 then remained relatively constant until decreasing slightly in year 5. Delta13C litter discrimination may have been masked by interfering delta13C fractionations or feedbacks between decomposers and litter chemistry. Our data indicate that isotopic discrimination is characteristic of early litter decay stages. These results may highlight aspects of isotope discrimination and nutrient cycling unique to arid land environments. Additional studies will be needed to confirm this.

}, keywords = {decomposition, isotopes, isotopes, decomposition, LIDET, long-term decomposition, nitrogen isotope, soil organ matter, SOM}, doi = {10.1016/S0038-0717(00)00113-9}, url = {files/bibliography/JRN00337.pdf}, author = {S. L. Connin and Feng, X. and R. A. Virginia} } @proceedings {50993, title = {Improved snow cover remote sensing for snowmelt runoff forecasting}, volume = {267}, year = {2001}, note = {Enter in ARIS at Beltsville January 15, 2001}, month = {August 30, 2001}, pages = {61-65}, abstract = {A system based on satellite remote sensing has been developed for snow cover monitoring of a number of basins in the Spanish Pyrenees. The snow covered area is used as an input for snowmelt runoff forecasts on 42 basins using the Snowmelt Runoff Model (SRM). The forecasted snowmelt volume accumulated from May to September is sent to the hydropower companies for water resources management. A subpixel analysis is carried out to map the snow cover with Advanced Very High Resolution Radiometer (AVHRR) data on board the National Oceanic and Atmospheric Administration (NOAA) satellites. Two mapping methods are compared: a linear combination of a visible and a near infrared channel, and a snow classification based on the Normalized Difference Snow Index (NDSI) and the Normalized Difference Vegetation Index (NDVI).}, url = {/files/bibliography/01-052.pdf}, author = {E. Gomez-Landesa and A. Rango and D. K. Hall} } @inbook {51018, title = {Inorganic carbon sequestration in grazing lands}, booktitle = {The potential of U.S. grazing lands to sequester carbon and mitigate the greenhouse effect}, year = {2001}, note = {//USDA//LTER III//ProCite field[6]: In}, month = {2001}, pages = {87-118}, publisher = {CRC Press}, organization = {CRC Press}, address = {Boca Raton, FL}, abstract = {

Carbonate C as CaCO3 (also termed soil inorganic C, or SIC) is a principal component of many arid and semiarid soils throughout the world (Dregne, 1976). In reference to soil profiles in southern New Mexico, for example, Ruhe (1967, p. 55) said that the subsoil horizon of calcium carbonate is so prominent that it is the first feature to catch an observerˊs eye. The amount of carbonate that forms in an arid or semiarid soil depends highly on soil age (Gile et al., 1966; Hawley et al., 1976). In young soils of Holocene age, only enough carbonate has formed to make filaments or coatings composed of silt and clay sized CaCO3 crystals. With increasing age, the amount of carbonate crystals progressively accumulates, plugging soil pores, engulfing other soil particles, and eventually forming calcic and petrocalcic horizons (Soil Survey Staff, 1998).

}, keywords = {book, books, carbon, inorganic sequestration, chapter, chapters, global change, carbon sequestration, report, reports}, url = {files/bibliography/JRN00335.pdf}, author = {Curtis H. Monger and J. Martinez-Rios}, editor = {Follett, R.F. and Kimble, J.M. and R. (ed.) Lal} } @article {51024, title = {Impact of small mammal disturbances on sediment yield from grasslasnd and shrubland ecosystems in the Chihuahuan Desert}, journal = {Catena}, volume = {44}, year = {2001}, note = {//NMSU//LTER IV//}, month = {2001}, pages = {285-303}, abstract = {

This study examines water and sediment movement on Summerford bajada in the Jornada Basin, N.M. Forty-five rainfall simulation experiments were conducted on 1- and 2-m2 runoff plots in grassland, degraded grassland, and shrubland communities. Within the shrubland community separate experiments were conducted in shrub and intershrub environments. Regression analyses indicate that for a 30-min rainfall at approximately 130 mm h-1, water yeilds on these environments are negatively related to the percentage of ground covered by vegetation and/or litter. In the degraded grassland and intershrub environments, sediment concentration is positively correlated with the average diameter of small mammal disturbances, suggesting that animal digging is an important factor controlling rates of erosion in these environments. Sediment concentration is not correlated with any surface property in the grassland or shrub environments. An analysis of water yeidls and sediment concentrations at 5-min intervals during the 30-min simulated rainfall experiments reveals that the influence of the above-mentioned factors on runoff and erosion is established furing events as short as 10-15 min. {\textcopyright} 2001 Elsevier Science B.V. All rights reserved.

}, keywords = {animal disturbance, sediment yield, article, articles, biopedturbation, sediment yield, desert hillslopes, grassland, biopedturbation, hydrology, sediment yield, hydrology, surface runoff, journal, journals, shrubland, biopedturbation, zoogeomorphology}, doi = {10.1016/S0341-8162(01)00133-3}, url = {files/bibliography/JRN00334.pdf}, author = {Melissa Neave and Athol D. Abrahams} } @article {51048, title = {Introduction to special section on mineral dust: outstanding problems in quantifying the radiative impact of mineral dust}, journal = {Journal of Geophysics Research}, volume = {106}, year = {2001}, note = {//??//LTER IV//}, month = {2001}, pages = {15-18}, abstract = {

This paper provides an introduction to the special section of the Journal of Geophysical Research on mineral dust. We briefly review the current experimental and theoretical approaches used to quantify the dust radiative impacts, highlight the outstanding issues, and discuss possible strategies to overcome the emerging problems. We also introduce the contributing papers of this special section. Despite the recent notable advances in dust studies, we demonstrate that the radiative effects of dust remain poorly quantified due to both limited data and incomplete understanding of relative physical and chemical processes. The foremost needs are (1) to quantify the spatial and temporal variations of dust burden in the atmosphere and develop a predictive capability for the size- and composition-resolved dust particle distribution; (2) to develop a quantitative description of the processes that control the spatial and temporal variabilities of dust physical and chemical properties and radiative effects; (3) to develop new instrumentation (especially to measure the dust particle size distribution in a wide range from about 0.01 μm to 100 μm, scattering phase function and light absorption by dust particles); and (4) to develop new techniques for interpreting and merging the diverse information from satellite remote sensing, in situ and ground-based measurements, laboratory studies, and model simulations. Because dust distribution and effects are heterogeneous, both spatially and temporally, a promising strategy to advance our knowledge is to perform comprehensive studies at the targeted regions affected by mineral dust of both natural and anthropogenic origin.

}, keywords = {atmosphere, dust burden, impacts, mineral dust, quantifying, radiative, spatial and temporal variations}, doi = {10.1029/2000JD900498 }, url = {files/bibliography/JRN00336.pdf}, author = {Sokolik, I. N. and Winkler, D. and Gilles Bergametti and D. E. Gillette and Carmichael, G. and Kaufman, Y. and Gomes, L. and Schuetz, L. and Penner, J.} } @inbook {51060, title = {Invertebrates: Their effects on the properties and processes of desert ecosystems}, booktitle = {Ecology of Desert Environments}, year = {2001}, month = {January 1, 2001}, pages = {333-356}, publisher = {Scientific Publishers}, organization = {Scientific Publishers}, address = {Jodhpur, India}, abstract = {This book chapter summarizes the role of invertebrate animals as regulators of ecosystem processes and their effects on the properties of ecosystem properties in arid lands. Several groups of invertebrates are key players in decomposition and nutrient cycling processes. Soil nematodes that feed on bacteria and fungi regulate the population growth of these soil microbes, thereby affecting the rates of decomposition, nitrogen mineralization, and rates of cycling of other nutrients. Soil nematode populations are regulated by predation by several taxa of mites. Fungal feeding mites are also directly involved in mineralization processes and are key invertebrates in nutrient cycling because they maintain activity in dry soils. Soil bacteria, protozoans and nematodes cease activity when soil water potentials fall below the wilting point for agronomic plants. The most important arid soil animals are termites. Termites supplant earthworms in arid soils as the animals that process dead plant material. Termites process between 30\% and 70\% of dead plants, depending upon the species, and also process much of the dung of large herbivores. Because of the efficiency of the microflora and microfauna in the hind gut of termites, most of the plant material they consume is converted to carbon dioxide and water. There is a strong negative correlation between termite abundance and soil organic matter in Chihuahuan Desert rangelands and African rangelands. Termites are primarily responsible for the low organic carbon content of desert rangeland soils.Pedogenesis (soil formation) in arid environments is significantly affected by invertebrate animals. Desert snails consume large quantities of soil algae, grind surfaces of exposed limestone and grind soil crusts. Their fecal material is chemically and physically different from the materials that are ingested, thereby contributing to soil formation. Burrowing and nest building by ants, isopods, and burrowing spiders results in soil turnover with subsoil deposited on the surface. This activity is functionally similar to plowing but over geological time periods. Termites build above-ground nests and foraging galleries and sheeting from subsurface soils, thereby contributing to soil turnover and pedogenesis.In arid rangeland soils invertebrates directly affect hydrological properties of soil by the production of macropores. Macropores are continuous tubes or spaces (voids) in the soil with diameters larger than spaces in which capillary water movement occurs. During rains, water moves down macropores by bulk flow. Bulk flow is rapid and quickly wets deep soil layers around macropores. Arthropods in order of relative importance for the production of macropores in arid rangelands are: termites, ants, isopods, burrowing spiders, cicadas, and beetles. Emperical measurements of the effects of subterranean termites on hydrology have shown that infiltration rates on plots with termites are more than double those on plots with termites eliminated.Several species of ants and termites have been documented to be responsible for producing fertile patches in arid rangelands and thereby affecting plant production and plant species composition of the patches. Insects not only affect plant production by changing soil fertility, some species of Cerambicid beetles and Bostrichid beetles stimulate productivity of mesquite (Prosopis glandulosa) by girdling or boring into stems to provide safe sites for larval development. Mesquite exhibits compensatory growth by producing a number of stem leaders at nodes below the girdle or bore entrance. The pruning of shrubs by girdling and boring insects exacerbates the problem of shrublands that resist control efforts and remain in a degraded state.}, keywords = {arid lands, decomposition, ecosystem processes, invertebrates, macropores, properties}, url = {/files/bibliography/01-055.pdf}, author = {Walter G. Whitford}, editor = {Prakash, I.} } @proceedings {51063, title = {The impact of the structure and composition of shrub-coppice dune landscapes on MASTER reflectance anisotropy}, volume = {IAHS Publication No. 267}, year = {2000}, note = {Proceedings of a symposium held at Santa Fe, NM, April 2000}, month = {2001}, pages = {162-167}, publisher = {Remote Sensing and Hydrology}, address = {Santa Fe, NM }, abstract = {This study assess the effects of physical structure and composition of shrub-coppice dune landscapes on anisotropy in the NASA MODIS-ASTER Airborne Simulator (MASTER) solar channels, and investigates the viability of simulating multi-angular data sets using off-nadir airborne imaging radiometry from a single overpass by means of data segmentation.}, keywords = {anisotropy, dunes, landscape, mesquite, multiple view angle, New Mexico, structure}, url = {/files/bibliography/01-080.pdf}, author = {M. Chopping and T. J. Schmugge and A. Rango and Jerry Ritchie and William P. Kustas} } @article {51121, title = {Indicators of Great Basin rangeland health}, journal = {Journal of Arid Environments}, volume = {45}, number = {4}, year = {2000}, month = {August 1, 2000}, pages = {289-304}, abstract = {

Early-warning indicators of rangeland health can be used to estimate the functional integrity of a site and may allow sustainable management of desert rangelands. The utility of several vegetation canopy-based indicators of rangeland health at 32 Great Basin rangeland locations was investigated. The indicators were originally developed in rangelands of the Chihuahuan Desert. Soil resources are lost through wind and water-driven erosion mainly from areas unprotected by plant canopies (i.e. bare soil). Study sites in Idaho had the smallest bare patches, followed by sites in Oregon. The more arid Great Basin Sagebrush Zone sites in Utah had the largest bare patches. Several vegetational indicators including percent cover by vegetation, percent cover by life-form, percent cover by sagebrush, and percent cover by resilient species were negatively related to mean bare patch size and are potential indicators of Great Basin rangeland condition. Plant community composition and the range of bare patch sizes were different at sites in the three locations in Idaho, Oregon and Utah. Therefore, expected indicator values are location specific and should not be extrapolated to other locations. The condition of study sites were often ranked differently by different indicators. Therefore, the condition of rangeland sites should be evaluated using several indicators.

}, keywords = {Great Basin, indicators, management, rangeland health}, doi = {10.1006/jare.2000.0645}, url = {/files/bibliography/00-014.pdf}, author = {A.G. de Soyza and Justin Van Zee and Walter G. Whitford and A.C. Neale and Tallent-Hallsel, N. and Jeffrey E. Herrick and Kris Havstad} } @conference {51067, title = {Fluorensia cernua extracts decrease intake of alfalfa pellets by sheep}, booktitle = {2000 Joint Meeting, American Society of Animal Science/American Dairy Science Association}, volume = {78}, number = {Suppl. 1}, year = {2000}, month = {2000}, pages = {113}, publisher = {Journal of Animal Science}, organization = {Journal of Animal Science}, abstract = {

Our objective was to evaluate the effects of 3 extracts (hexane, ether and ethanol) isolated from tarbush on intake of alfalfa pellets by sheep. In each of 2 experiments, 45 ewe lambs received 1 of 5 treatments for 5 d. Treatments were alfalfa pellets (CON) or alfalfa pellets plus ethanol carrier (CAR), hexane extract (HEX), ether extract (ETH) or ethanol extract t(ETOH). Treatments were isolated from tarbush leaves (36 kg) using a sequential extraction of hexane, diethyl ether and 100\% ethanol. Extractions (3 kg of leaves in 7 L of solvent, constant mixing, 22 h per solvent) were filtered, solvents removed using a rotary evaporator and resuspended in ethanol. Lambs were offered 640 g of alfalfa pellets (DM basis) and intake was monitored during a 20-min interval each morning. Extracts were applied to alfalfa pellets at the same concentration as in tarbush in Exp. 1, and at 10-fold dilutions in Exp. 2. Lambs were adapted to handling and individual pen feeding for 10 d and maintained and fed alfalfa pellets (4.7\% of BW, DM basis) as one group except during 20-min tests. All 3 extracts reduced intake by lambs in Exp. 1 ( P \< .0001) compared to CON or CAR. Mean intake during the 20-min period was 361, 393, 204, 212 and 228 g for CON, CAR, HEX, ETH and ETOH, respectively (SEM=28.9). Intake did not differ between CON and CAR, nor among HEX, ETH and ETOH. Mean intake in Exp. 2 was not different (468, 455, 389, 381 and 431 g for CON, CAR, HEX, ETH and ETOH, respectively; SEM =30.5; P =.187). Three fractions containing mixtures of compounds of increasing polarity were equally effective in decreasing intake of alfalfa pellets at concentrations encountered in intact tarbush plants; thus, several compounds are probably involved in the low palatability of this shrub exhibited by livestock.

}, keywords = {alfalfa pellets, extracts, Fluorensia cernua, intake, sheep, tarbush, treatments}, author = {Richard E. Estell and M.R. Tellez and E.L. Fredrickson and D.M. Anderson and Kris Havstad and M.D. Remmenga} } @proceedings {51083, title = {Integrating soil processes into management: From microaggregates to macrocatchments}, volume = {1}, year = {2000}, month = {July 17-23, 1999}, pages = {91-95}, address = {Townsville, Australia}, abstract = {

Soil properties and processes are rarely considered in range management, or in monitoring or assessment of range condition. An implicit assumption of most management programs is that soil properties are correlated with vegetation, so it is only necessary to manage and monitor the plant community. However, most range managers recognize that the plant communities which could exist at a particular site fundamentally depend on soil properties, and that many of these properties are dynamic and respond to management. A reduction in soil organic matter content, or a change in its distribution (dynamic properties), are frequently cited as indicators of land degradation (Northup \& Brown 1999a,b). There are numerous reports demonstrating relationships between soil properties and processes and the capacity of rangelands to support diverse plant and animal communities (National Research Council 1994) and plant and animal production (Elkins et al. 1986; Whitford et al. 1987; Whitford \& Parker 1989; Whitford \& Herrick 1995), and maintain air quality (Belnap \& Gillette 1998) and water quality (National Research Councill993).

}, keywords = {ecosystem health, indicators, management, monitoring, soil processes}, url = {/files/bibliography/00-001.pdf}, author = {Jeffrey E. Herrick and Walter G. Whitford} } @article {51088, title = {Impact of grazing and desertification in the Chihuahuan Desert: Plant communities, granivores and granivory}, journal = {American Midland Naturalist}, volume = {144}, number = {1}, year = {2000}, month = {July 1, 2000}, pages = {78-91}, abstract = {

Livestock effects on plant communities through overgrazing (desertification) should affect the structure and functioning of semiarid rangeland communities. We measured plant, granivorous ant and rodent communities and rates of seed removal by rodents and ants in grazed (by livestock) and ungrazed desert grasslands, as well as mesquite and creosotebush shrublands to test hypotheses on the effects of grazing and desertification on ecosystem structure and functioning. In desert grasslands, grazing reduced the cover of perennial grasses, particularly the dominant Bouteloua eriopoda, but the cover of forbs and shrubs did not differ between treatments. One species of perennial grass, Dasyochloa pulchellum, increased in grazed grasslands compared with grassland exclosures. Detrended correspondence analysis showed that grazing caused desert grasslands to shift in community structure towards the shrublands. There were more seed harvesting ant and rodent species in the creosotebush shrublands than in the grasslands and mesquite shrublands. Grazing had no effect on the diversity of ants or rodents within grasslands, and detrended correspondence analysis revealed no clear trends in granivorous ant community structure in the grazed and ungrazed grasslands or the mesquite and creosotebush shrublands. Ants removed more seeds than did rodents in the grassland sites, but rodents removed more seeds than did ants in the creosotebush sites; seed removal rates by rodents and ants were the same in the mesquite sites. Our data support the hypothesis that livestock grazing leads to a shift from grassland to shrubland in the Chihuahuan Desert with associated changes in the structure and functioning of faunal communities. Because grasslands support few species and low densities of rodents, seed harvesting ants are the most important granivores in these desert grasslands. On a larger scale, we therefore hypothesize that the observed dominance of rodents as seed harvesters in the Chihuahuan Desert is a function of the desertification of desert grasslands to shrublands by livestock and that associated feedback effects may complicate the regeneration of degraded communities.

}, keywords = {Chihuahuan Desert, desertification, granivores, granivory, grazing, livestock, overgrazing}, doi = {10.1674/0003-0031(2000)144[0078:IOGADI]2.0.CO;2}, url = {/files/bibliography/00-010.pdf}, author = {G. I. H. Kerley and Walter G. Whitford} } @conference {51090, title = {The influence of kangaroo rat mounds on species diversity and abundance in two grassland types at a semiarid ecotone}, booktitle = {85th Annual Meeting, Ecological Society of America}, year = {2000}, month = {August 6-10, 200}, pages = {300}, address = {Snowbird, UT}, abstract = {Our objective was to evaluate the effects of kangaroo rat mounds on species diversity and composition at a semiarid-arid grassland ecotone. We expected that source populations of plants occurring on kangaroo rat mounds have important influences on species composition of vegetation at the landscape scale and that these influences differ by grassland type. Our study was conducted at the Sevilleta LTER in New Mexico, where a grassland type dominated by Bouteloua gracilis, a shortgrass steppe species, and a grassland dominated by B. eriopoda, a desert grassland species, meet to form patches across the landscape. Four 0.4 ha plots were sampled for species diversity and composition within a 7m x 7m grid in each grassland type. Kangaroo rat mounds were also mapped and sampled for vegetation measures in 4 areas of 1.6 ha in each type. The landscape scale abundance of many subordinate species was increased significantly by populations occurring on kangaroo rat mounds in both grassland types. However, the are affected by the burrowing activity of kangaroo rats was twice as large in the B. eriopoda dominated grassland type. Furthermore, dominant plants on mounds in the B. eriopoda type were also abundant in off-mound areas whereas dominant plants on mounds in the B. gracilis type were not as abundant off-mound. These results indicate that the presence of mounds in the B. gracilis dominated type is creating islands of plant communities that are distinct from the rest of the grassland. Therefore, the occurrence of certain plant species in this grassland type may be intimately associated with the disturbance regime at this ecotone.}, keywords = {composition, grassland ecotone, kangaroo rat mounds, Sevilleta LTER, species diversity}, author = {G. Kroel-Dulay and Hochstrasser, T. and Debra C. Peters} } @book {51100, title = {Interpreting Indicators of Rangeland Health, Version 3}, year = {2000}, note = {Interagency Technical Reference 1734-6}, month = {December 1, 2000}, pages = {115}, publisher = {USDI, Bureau of Land Management}, organization = {USDI, Bureau of Land Management}, address = {Denver, CO}, abstract = {

This technical reference describes a new qualitative assessment protocol to be used for interpreting indicators of rangeland health. Use of the reference will allow for more consistent interpretations of rangeland health indicators, thus making assessment results more comparable. The procedure has been developed for use by experienced, knowledgeable land managers as it requires a good understanding of ecological processes, vegetation, and soils for each of the sites to which it is applied. If used by knowledgeable and experienced people, they will be able to make rapid and preliminary evaluations of soil and site stability, hydrologic function, and biotic integrity on rangelands. It is not to be used for monitoring. The procedure requires that evaluators rate 17 indicators to assess 3 attributes (soil/site stability, hydrologic function, and biotic integrity) for a given location.

}, keywords = {biotic integrity, hydrologic function, indicators, rangeland health, soil and site stability}, url = {files/bibliography/00-021.pdf}, author = {M. Pellant and P. L. Shaver and D.A. Pyke and Jeffrey E. Herrick} } @article {51118, title = {Influence of small-scale disturbances by kangaroo rates on Chihuahuan Desert ants}, journal = {Oecologia}, volume = {125}, year = {2000}, month = {2000}, pages = {142-149}, abstract = {Banner-tailed kangaroo rats (Dipodomys spectabilis) are prominent ecosystem engineers that build large mounds that influence the spatial structuring of fungi, plants, and some ground-dwelling animals. Ants are diverse and functionally important components of arid ecosystems; some species are also ecosystem engineers. We investigated the effects of patch disturbances created by D. spectabilis mounds on ant assemblages in a Chihuahuan Desert grassland in southern New Mexico by using pitfall traps in a paired design (mound vs matrix). Although the distrubances did not alter species richness or harbor unique ant communities relative to the matrix, they did alter species composition; the abundances of 6 of 26 species were affected. The distrubances might also act to disrupt spatial patterning of ants caused by other environmental gradients. In contrast to previous investigations of large-scale disturbances, we detected no effects of the disturbances on ants at the fucntional-group level. Whether ant communities respond to disturbance at a functional-group or within-functional-group level may depend on teh size and intersity fo the disturbance useful function-group schemes also may be scale-dependent, however, or species may respond idiosyncratically. Interactions between distrubance-generating ammmals and ants may produce a nested spatial structure of patches.}, keywords = {disturbances, ecosystem engineers, formicidae, heteromyidae, spatial scale}, url = {/files/bibliography/00-022.pdf}, author = {Robert L. Schooley and Brandon T Bestelmeyer and J.F. Kelly} } @conference {51148, title = {Invasion of grasslands by exotic perennial weeds: Allelopathy and soil texture effects}, booktitle = {84th Annual Meeting of the Ecological Society of America}, volume = {80}, year = {1999}, month = {1999}, pages = {94}, address = {Spokane, WA}, abstract = {Invasion of native ecosystems by exotic perennial weeds is an increasingly important ecological problem, yet the key processes involved remain poorly understand for many species. Our objective was to evaluate the importance of allelopathy to the invasion by Acroptilon repens (Russian knapweed) into native semiarid grasslands. Based upon the inverse texture hypothesis, we expected the strength of the allelopathic affect to be related to soil texture and its effects on soil water availability. We used an individual plant-based simulation model (ECOTONE) to evaluate the importance of allelopathy to invasion by Russian knapweed into shortgrass communities in eastern Colorado over a range of soil textures. We found that allelopathy was more important for fine-textured soils where allelochemicals became concentrated in the rooting zone of grasses compared to soils with high sand contents where leaching of allelochemicals occurred. Rates of invasion nwere faster and more complete dominance by Russian knapweed occurred on fine- compared to coarse-textured soils. Our results have important implications for the management and sustainability of these grasslands under the threat of invasion by perennial weeds.}, keywords = {Allelopathy, grasslands, invasion, perennial weeds, soil texture}, author = {Sarah Goslee and Debra C. Peters and Beck, K.G.} } @article {51154, title = {Improving sustainability of arid rangelands}, journal = {New Mexico Journal of Science}, volume = {39}, year = {1999}, month = {November 1, 1999}, pages = {174-197}, abstract = {Deserts are climatically defined and arid regions within deserts are usually identified using a combination of average precipitation, evaporation, and temperature features. More generally though, arid regions are defined as areas receiving less than 250 mm of annual precipitation on a long-term average. In New Mexico, 10\% of the state is classified as arid, ,but this region supports 77\% of its population and nearly 30\% of its agricultural lands. However, the arid zone is classified primarily as rangeland. Improving the sustainability of these arid rangelands will require employing technologies that exploit or augment natural processes and that are effective at relatively small, affordable spatial scales. Many of these technologies have been identified but the need exists to revise their application to comply with these two requirements. Implementing adaptive management within this arid zone will require flexibility, active collaborations among users, stewards and public interests, and increased efforts in monitoring effects of management on ecological conditions of arid lands.}, url = {/files/bibliography/560.pdf}, author = {Kris Havstad} } @conference {51157, title = {The influence of dominant plants on water dynamics at a semiarid grassland-shrubland ECOTONE: implications for the recruitment of Larrea tridentata}, booktitle = {84th Annual Meeting, Ecological Society of America}, volume = {80}, year = {1999}, month = {August 8-12, 199}, pages = {109}, address = {Spokane, WA}, abstract = {We evaluated the effects of dominant grasses and shrubs on soil water dynamics and recruitment success at a grassland-shrubland ecotone. Microsites around the dominant grass (Bouteloua eriopoda) and the dominant shrub (Larrea tridentata) were observed to support different subdominant plants at the Sevilleta National Wildlife Refuge LTER site in central New Mexico. We hypothesized that these two dominants differ in their influence on soil water dynamics, which, together with soil texture differences, result in differential recruitment between microsites. We were particularly interested in recruitment of shrubs that may promote their invasion into grasslands. We used a daily time-step soil water model to evaluate the effects of different dominant species on the establishment of L. tridentata. We were interested in the effects of these species on light and soil water resources. Our results indicated that, although B. eriopoda plants effectively acquired water during the growing season, recruitment of L. tridentata could occur in these microsites near the end of the growing season when the grass was becoming dormant. This resulted in higher probabilities of recruitment of Larrea in grass-dominated microsites than in shrub microsites. This contrasts with field observations showing that germination of L. tridentata was higher in shrub than grass microsites. Therefore, recruitment is also affected by other factors, including seed availability. These results further our understanding of the dynamics of grass-shrub interactions and provide one mechanism to explain shrub invasion into grasslands.}, author = {Hochstrasser, T. and Debra C. Peters} } @conference {51167, title = {The importance of landscape-scale processes in the vegetation of sand grasslands along a climatic gradient}, booktitle = {84th Annual Meeting, Ecological Society of America}, volume = {80}, year = {1999}, month = {August 8-12, 199}, pages = {270}, address = {Spokane, WA}, abstract = {A sharp gradient in the diversity and productivity of sand grasslands exists within 200 km in the Central European forest-steppe transition zone in Hungary. Our objective was to investigate the relative importance of climate and landscape-level processes in explaining these changes in grasslands. We were particularly interested in the importance of a forest mosaic located in the north that does not exist in the south. We used an individual plant-based simulation model (ECOTONE) to evaluate the effects of climate and factors associated with forest cover on grassland dynamics for two sites at the ends of the gradient. Climate was found to be less important than forest factors in explaining differences in vegetation. Incorporating factors associated with higher forest cover (ie., increased relative humidity, availability of different species) as well as indirect effects of climate (higher soil organic matter) into the model produced results similar to observed vegetation. Our results demonstrate that landscape-level processes can magnify climatic differences, and can contribute to the development of sharp gradients in vegetation, particularly at transition zones.}, author = {G. Kroel-Dulay and Kovacs-Lang, E. and Debra C. Peters} } @mastersthesis {51175, title = {Impact of small mammal disturbances on water and sediment yields in the Jornada Basin, southern New Mexico}, year = {1999}, note = {//NMSU//NONE, LTER//ProCite field[12]: In File}, month = {1999}, pages = {243}, school = {SUNY at Buffalo}, type = {Ph.D. Dissertationpp}, address = {Buffalo, NY}, abstract = {This study examines water and sediment movement on a bajada in the Jornada Basin, New Mexico. Forty-five rainfall simulation experiments were conducted on 1 m2 and 2 m2 runoff plots in grassland, degraded grassland, and shrubland communities. Within the shrubland community separate experiments were conducted in shrub and intershrub environments. Regression analyses indicate that for a 30-min rainfall at approximately 130 mm h1, water yields on these environments are negatively related to the percentage of ground covered by vegetation and/or litter. In the degraded grassland and intershrub environments, sediment concentration is positively correlated with the average diameter of small mammal disturbances, suggesting that animal digging is an important factor controlling rates of erosion in these environments. Sediment concentration is not correlated with any surface property in the grassland or shrub environments. An analysis of water yields and sediment concentrations at 5-min intervals during the 30-min simulated rainfall experiments reveals that the influence of the above-mentioned factors on runoff and erosion is established 10 to 15-min into a rainfall event. A comparison among the different communities indicates that the shrubland (incorporating both shrub and intershrub environments) produces higher water and sediment yields than either the grassland or the degraded grassland. This finding has important implications for the historical replacement of grassland by shrubland. ... Thus the impact of small mammals on the erosion, transport, and redeposition of sediment in the study area depends not only on the amount of activity by the animals but also on the average distance to a rill. Because intense animal activity and short interrill flow paths occur together only in the shrubland, it is evident that this is the community where degradation of the soil by small mammals has been greatest.}, keywords = {dissertation, dissertations, disturbance, rodent, hydrology,, hydrology, grassland, hydrology, rainfall simulation, hydrology, sediment transport, hydrology, shrubland, hydrology, surface runoff, hydrology,sediment yield, rodent, hydrology, runoff, rodent effects, sediment yield, theses, thesis}, author = {Melissa Neave} } @article {51185, title = {Impact of drought on desert shrubs: Effects of seasonality and degree of resource island development}, journal = {Ecological Monographs}, volume = {69}, number = {1}, year = {1999}, month = {February 1, 1999}, pages = {69-106}, abstract = {

Large areas of semiarid grasslands in the southwestern United States have been virtually replaced by shrubs during the past century. Understanding the causes and consequences of such vegetation dynamics requires that we elucidate the interplay between external forces of change (e.g., climate, human impacts) and the internal forces within these ecosystems that foster resilience and/or stability. Several conceptual models of and ecosystems address this interplay by including the potential role of autogenic shrub effects on ecosystem processes that lead to the formation of "resource islands" and tend to promote shrub persistence. Specifically, during the process of shrub establishment and maturation, the cycling of nutrients is progressively confined to the zones of litter accumulation beneath shrubs, while bare intershrub spaces become increasingly nutrient poor. As shrub resource islands develop, there is increased interception and stemfiow by shrub canopies, confining infiltration of nutrient-enriched rainfall directly beneath the shrubs; the barren intershrub spaces generate overland flow, soil erosion by wind and water, and nutrient losses. These islands are preferred sites for the regeneration of shrubs and herbaceous plants and are correlated with spatial variation in soil microbial populations and soil microfauna that promote nutrient cycling. If further changes in the transition between grassland and shrubland are to be correctly predicted, or if we wish to intervene and redirect transitions, we must develop a greater mechanistic understanding of the structural and functional relationships between shrubs and the resource islands associated with them.

}, keywords = {desertification, drought response, Jornada LTER, Larrea tridentata, prosopis glandulosa, resource island formation, shrub physiology, soil nitrogen, soil water}, doi = {10.2307/2657195 }, url = {/files/bibliography/680.pdf}, author = {J. F. Reynolds and R. A. Virginia and P. R. Kemp and A.G. de Soyza and Tremmel, D. C.} } @conference {51226, title = {Incorporation of soil quality indicators into rangeland monitoring programs in Mexico and the US}, booktitle = {Annual Meeting, American Society of Agronomy}, year = {1998}, month = {October 18-22, 1}, pages = {212-213}, address = {Baltimore, MD}, abstract = {The condition of rangelands is reflected in interactions between soil and vegetation However, soil indicators are rarely incorporated into rangeland monitoring programs High cost and problems associated with generalizing from samples from a single profile are frequently cited reasons. Recently developed rapid field indicators of soil surface stability, compaction and infiltration capacity were evaluated together with vegetation in a variety of rangeland ecosystems in the southwestern United States and northern Mexico. Soil measurements were completed at a minimum of 12 points at each monitoring site. Indicators derived from all three measurements complemented vegetation-based parameters, although not all indicators were appropriate for all sites Stratification by vegetative cover generally reduced the number of measurements required Based on the results and related work, decision trees were developed to aid selection of appropriate type and number of measurements.}, author = {Jeffrey E. Herrick and Royo, M. and Baez, A. and Melgoza, A. and L. Huenneke and Justin Van Zee and A.G. de Soyza and Walter G. Whitford and Kris Havstad} } @article {JRN54839, title = {Influence of habitat vegetative condition on trap response of rodents associated with burrow mounds of Dipodomys spectabilis in a desert grassland}, journal = {Southwestern Naturalist}, volume = {43}, year = {1998}, month = {June 1998}, pages = {269-273}, chapter = {269}, abstract = {

A variety of factors are \ known to \ play \ a role in\  \ susceptibility \ of\ \  small\  mammals \ to\  \ being trapped (Smith et al., \ 1975). Among the factors tested are trap-type (closed box \ live \ trap, pitfall trap, wire \ box live \ trap, snap trap), moonlight, \ season, food \ availability, and \ bait (see \ O{\textquoteright}Farrell et al. \ [1994] and Woodman et al [1996] for \ recent reviews). Although intuition suggests that habitat condition (e.g., food availability, cover) \ should \ influence \ small mammal trap response, few \ observations have been reported \ (Grinnell, 1932; Fitch, 1954; Smith and \ Blessing, 1969; O{\textquoteright}Farrell \ and\  Up-tain, 1987). Grinnell \ (1932) \ stated that giant kangaroo rats \ (Dipodomys ingens) \ ignored bait- ed snap-traps when new \ growth of \ forbs and grasses was available. Fitch (1954) showed that captures of a variety of small and medium-sized mammals declined in \ apparent concert with seasonal food availability. Smith \ and \ Blessing (1969) presented \ results that showed that experimental food augmentation decreased captures of old-field rodents. O{\textquoteright}Farrell and Uptain (1987) reported \ that Stephens{\textquoteright} kangaroo rats (D.\  \ stephensi)\  \ were\  \ nearly \ impossible \ to \ live- trap when vegetative cover and \ green \ vegetation were abundant.

}, keywords = {burrow mounds, desert grassland, Dipodomys spectabilis, habitat vegetative condition, rodents, trap response}, url = {https://www.academia.edu/29014632/Kay_F.R._1998._Influence_of_habitat_vegetative_condition_on_trap_response_of_rodents_associated_with_burrow_mounds_of_Dipodomys_spectabilis_in_a_desert_grassland._Southwestern_Naturalist_43_269-273?auto=download}, author = {F. R. Kay} } @article {51236, title = {Inconsistencies in net radiation estimates from use of several models of instruments in a desert environment}, journal = {Agricultural and Forest Meteorology}, volume = {90}, year = {1998}, note = {//USDA//LTER III//}, month = {1998}, pages = {257-263}, abstract = {

Studies of surface energy and water balance generally require an accurate estimate of net radiation and its spatial distribution. A project quantifying both short term and seasonal water use of shrub and grass vegetation in the Jornada Experimental Range in New Mexico prompted a study to compare net radiation observations using two types of net radiometers currently being used in research. A set of 12 REBS net radiometers were compared with each other and one Swissteco, over wet and dry surfaces in an arid landscape under clear skies. The set of REBS exhibited significant differences in output over both surfaces. However, they could be cross calibrated to yield values within 10 W m-2, on average. There was also a significant bias between the REBS and Swissteco over a dry surface, but not over a wet one. The two makes of instrument could be made to agree under the dry conditions by using regression or autoregression techniques. However, the resulting equations would induce bias for the wet surface condition. Thus, it is not possible to cross calibrate these two makes of radiometer over the range of environmental conditions observed. This result indicates that determination of spatial distribution of net radiation over a variable surface should be made with identical instruments which have been cross calibrated. The need still exists for development of a radiometer and calibration procedures which will produce accurate and consistent measurements over a range of surface conditions. {\textcopyright} 1998 Elsevier Science B.V.

}, keywords = {article, articles, instruments, net radiation, instruments, REBS, instruments, Swissteco, JORNEX, net radiation, journal, journals, net radiation, instrument comparison, remote sensing, JORNEX}, doi = {10.1016/S0168-1923(98)00062-8}, url = {files/bibliography/JRN00255.pdf}, author = {William P. Kustas and J.H. Prueger and Lawrence E. Hipps and J. Hatfield and Meek David} } @article {JRN54975, title = {Image Comparisons of Snow and Ice Crystals Photographed by Light (Video) Microscopy and Low-Temperature Scanning Electron Microscopy}, journal = {Scanning}, volume = {20}, year = {1998}, month = {02/1998}, pages = {285-296}, chapter = {285}, abstract = {

Light (video) microscopy and low-temperature scanning electron microscopy (SEM) were used to examine and record images of identical precipitated and metamorphosed snow crystals as well as glacial ice grains. Collection procedures enabled numerous samples from distant locations to be shipped to a laboratory for storage and/or observation. The frozen samples could be imaged with a video microscope in the laboratory at ambient temperatures or with the low-temperature SEM. Stereo images obtained by video microscopy or low-temperature SEM greatly increased the ease of structural interpretations. The preparation procedures that were used for low-temperature SEM did not result in sublimation or melting. However, this technique did provide far greater resolution and depth of focus over that of the video microscope. The advantage of resolution was especially evident when examining the small particles
associated with rime and graupel (snow crystals encumbered with frozen water droplets), whereas the greater depth of focus provided clearer photographs of large crystals such as depth hoar, and ice. Because the SEM images contained only surface information while the video images were frequently confounded by surface and internal information, the SEM images also clarified the structural features of depth hoar crystals and ice grains. Low-temperature SEM appears to have considerable promise for future investigations of snow and ice.

}, keywords = {ice, low-temperature scanning electron microscopy, snow crystals, video microscopy}, url = {files/bibliography/Rango1998-06.pdf}, author = {W.P. Wergin and A. Rango and E. R. Erbe} } @article {51269, title = {Isotopic study of environmental change from disseminated carbonate in polygenetic soils}, journal = {Soil Science Society of America Journal}, volume = {61}, year = {1997}, note = {//?//LTER III//}, month = {1997}, pages = {1710-1722}, abstract = {

We evaluated the extent to which delta 13C and delta 18O values of disseminated carbonate preserve a signal of Holocene and modern vegetation changes in polygenetic soils of the Jornada Basin, New Mexico. Factors and processes influencing carbonate chemistry were constrained in a relict grassland community and recent mesquite [Prosopis glandulosa var. torreyana (L. Benson) M. Johnston] dunes, using 14C dates and delta 13C data of soil organic matter (SOM) as independent measures of site history. Total-profile carbonate contents ranged from 39 to 451 kg m ! due to local patterns of soil water infiltration and erosion. In grassland soils, 14C ages and delta 13C values of disseminated carbonate in A and B horizons were influenced by the presence of older detrital carbonate, reworked from surrounding surfaces. As a result, carbonate isotopes did not record mid-Holocene climate and vegetation changes, which were inferred from delta I3C values of coexisting SOM. Shrub expansion during the past century was recorded by changes in the delta 13C values of disseminated carbonate and SOM from mesquite dunes. Carbon-14 data and mass balance estimates indicated that at least 80\% of the dune carbonate (in C horizons) has been isotopically altered by dissolution and recrystallization processes in \<100 yr. The modern carbonate is apparently forming from soil waters composed of nearly equal amounts of summer and winter rainfall, as evidenced by carbonate delta 18O values. Our analyses indicate that disseminated carbonate can provide a meaningful environmental signal in polygenetic soils, when pedogenic contributions to isotopic variability are constrained.

}, keywords = {isotopes, soil carbonate, journal, journals, mesquite dunes, soil organic matter, soil, carbonate, SOM}, doi = {10.2136/sssaj1997.03615995006100060024x}, url = {files/bibliography/JRN482.pdf}, author = {S. L. Connin and R. A. Virginia and Chamberlin, C. P.} } @book {51291, title = {Interactions between demographic and ecosystem processes: A challenge for functional types}, series = {Plant Function Types}, year = {1997}, note = {//OTHER//LTER III//ProCite field[6]: In}, month = {1997}, pages = {234-254}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, address = {Cambridge}, keywords = {book, books, chapter, chapters, demography, ecosystem, processes, report, reports}, author = {Laurenroth, W. K. and D.P. Coffin and Ingrid C. Burke and R. A. Virginia}, editor = {Smith, T. M. and Shugart, H. H. and Woodward, F. I. (eds.)} } @article {JRN54970, title = {Incorporating Radiation Inputs into the Snowmelt Runoff Model}, journal = {Hydrological Process}, volume = {10}, year = {1996}, month = {04/1996}, pages = {1329-1343}, chapter = {1329}, abstract = {

Process-based, distributed-area snowmelt runoff models operating at small scales are essential to understand subtle effects of climate change, but require data not commonly available. Temperature index models operating over large areas provide realistic simulations of basin runoff with operationally available data, but lack rigorous physically based algorithms. A compromise between the two types of models is required to provide realistic evaluations of basin response to environmental changes in cold regions. One adaptation that is uniformly required for snowmelt models is the use of remotely sensed data, either as input or in model validation. At a minimum, snowmelt forecasting models need to incorporate snowcover extent information, which is currently obtained operationally. As more remote sensing capabilities come on line, models should accept upgraded information on snow water equivalent; additional remotely
sensed information on landcover, frozen soil, soil moisture, cloudiness and albedo would also be useful. Adaptations to the semi-distributed snowmelt runoff model (SRM) are underway to make it more physically based for use in large area studies. A net radiation index has been added to the model, which formerly used only a temperature (degree-day) index to melt snow from a basin{\textquoteright}s elevation zones. The addition of radiation to the SRM allows the basin to be subdivided into hydrological response units by general aspect (orientation) as well as elevation. Testing of the new radiation-based SRM with measured radiation from a small research basin is the first step towards large scale simulations. Results from the W-3 research basin in Vermont, USA are promising. In the radiation version, the factor that multiplies the degree-day index is estimated independently of model output and is held constant throughout the season, in contrast with the degree-day version, where the corresponding factor is allowed to increase throughout the season.
Without calibrating or optimizing on this important parameter, the goodness-of-fit measure R2 is improved in two out of six test years when the radiation version of the SRM is used in place of the degree-day version in melt season simulations. When the accumulation of error is eliminated with periodic updating of streamflow, more significant improvement is noted with radiation included.

}, keywords = {degree-day, net radiation, runoff, snowmelt}, url = {files/bibliography/Rango1996-04.pdf}, author = {K.L. Brubaker and A. Rango and William P. Kustas} } @conference {51345, title = {Indicators of Soil Quality for Southwestern Rangelands}, booktitle = {Soil Qualilty: A Guide to Conservation Workshop}, year = {1996}, month = {July 17-18, 1996}, address = {Ames, IA}, keywords = {indicators, rangelands, soil quality, southwestern}, author = {Jeffrey E. Herrick} } @article {51378, title = {The importance of the biodiversity of soil biota in arid ecosystems}, journal = {Biodiversity and Conservation}, volume = {5}, year = {1996}, month = {1996}, pages = {185-195}, abstract = {

The importance of soil biota in maintaining ecosytem integrity is examined by a review of studies of soil processes and soil biota in arid ecosystems. In decomposition and mineralization processes, there is a temporal succession of microarthropod and nematode species. Tydeid mites are keystone species in the early stages of decomposition. Soil pore neck size variation affects the spatial distribution of soil biota and requires that species differ in size to provide efficient processing of organic matter. In arid ecosystems, the sub-set of soil biota that is active at any point in time is determined by the soil water potential and soil temperature. The structure of soil microarthropod assemblages is similar in several arid regions of the world and abundance and diversity are directly related to quantity of litter accumulations and soil organic matter. The unique life histories and behavioural characteristics of desert soil macrofauna (termites and ants) determine the effects of these organisms on soil properties and soil formation. The soil biota, by affecting the spatial and temporal distribution of essential sesources (water and nutrients), are essential to the maintenance of the ecosystem integrity of arid ecosystems.

}, keywords = {ants, diversity, functional groups, keystone species, microarthropods, nematodes, protozoans, termites}, doi = {DOI: 10.1007/BF00055829}, url = {/files/bibliography/504.pdf}, author = {Walter G. Whitford} } @article {51425, title = {Intersection of ecosystem and biodiversity concerns in the management of rangelands}, journal = {Natural Resources and Environmental Issues}, volume = {IV}, year = {1995}, month = {1995}, pages = {72-79}, abstract = {

Maintenance of ecological functions and disturbance regimes within ecosystems is as important as preserving species populations or their genetic structure, biotic communities, and landscapes. There is considerable dispute as to how species diversity influences productivity and stability of various ecosystem structural and dynamic attributes. Some view each and every species as making an incremental\  contribution\  to these features. Others assume that some redundancy exists. Addition or loss\  of species can be anecdotally shown to influence ecosystems in proportion to the role such organisms have in altering microclimate, capturing energy, cycling nutrients, and serving as food and habitat for other organisms. Subtle but essential\  interactions are easy to overlook, however. We should try to keep all the parts until\  more definitive research\  is available\  on\  this topic. Sustainable development will require balancing resource use with maintenance of our natural legacies. Ecosystem perspectives\  must contribute\  to decisions\  on where the balance exists.

}, keywords = {biodiversity, ecosystem, management, rangelands}, url = {files/bibliography/95-NatResandEnv-Whitford.pdf}, author = {West, N.E. and Walter G. Whitford} } @article {51437, title = {Influence of atmospheric CO2 on the decline of C4 plants during the last deglaciation}, journal = {Nature}, volume = {368}, year = {1994}, note = {//LOCAL//NONE//}, month = {1994}, pages = {533-536}, abstract = {Changes in atmospheric carbon dioxcide concentrations in the past may have caused changes in vegetation type, and it has been suggested that the isotopic signature of such vegetation shifts, preserved in palaeosols, might be used as a proxy for past CO2 variations. But the connection between palaeosol isotopic signatures and atmospheric CO2 concentrations has been difficult to establish, partly because of the unreliability of CO2 proxies and partly becuase of the difficulty in ruling out other potential causes of vegetation changes, such as climate. Here we present palaeosol carbon isotope ratios that reveal a shift from C4-dominated grasses to C3-dominated shrubs about 7-9 kyr ago on an alluvial fan system in the Chihuahuan desert, New Mexico. This coincides with a rapid increase in atmospheric CO2 concentration recorded in Antarctic ice cores and increased aridity recorded by geomorphic reconstructions and packrat remains. Palaeosol oxygen isotope ratios, which depend on temperature and moisture, were relatively constant during the vegetation shift, suggesting that the CO2 change, rather than climate, was the dominant cause. We conclude that the carbon isotope ratios of ancient soils can indeed be used as a proxy for past CO2 changes.}, keywords = {article, articles, calcium carbonate, carbon isotope ratios, geomorphology,atmospheric CO2, journal, journals, paleoclimate,CO2 variations, plant community, CO2 variations, plant,C4, soil,atmospheric CO2}, author = {David R. Cole and Curtis H. Monger} } @proceedings {51444, title = {Intake of cooked molasses blocks and subsequent performance of young postpartum cows grazing native range}, volume = {45}, year = {1994}, month = {1994}, pages = {76-79}, abstract = {Seventy-two two year-old first calf beef heifers, maintained at the USDA Jornada Experimental Range were used to investigate supplement intake and effects of protein and fat additions to cooked molasses blocks on cow body condition (BC) and weight change (BW), butritional status and reproductive performance in in first-calf beef heifers. Cows were randomly assigned within calving date and sex of calf to one of four treatment supplements and moved into one of four pastures ranging in size from 372 to 514 ha. Nutrients provided in blocks included: 1) an energy control (C) (10\% CP); 2) fat supplement (F) (10\% fat from Megalac and tallow, 10\% CP); 3) protein supplement (P) (27\% CP formulated to be 60\% ruminally undegradable protein from feater, blood and soybean meal) and; 4) P+F supplement (10\% fat and 27\% CP). Consumption of supplemental nutrients on a daily basis requreid block intake to be 1.4, 1.2, 1.4 and 1.5 kg/(animal x d), respectively, for C, F, P, and P+F. Mean block intake was 0.4, 0.6, 0.6, and 0.3 kg/(animal x d), respectively for C, P, F and P+F). Cow BW loss during first 74 d was mass (P= .01) in C fed cows compared with cows consuming F.}, keywords = {cooked molasses, native range, performance, postpartum cows}, author = {Gambill, M.D. and M.K. Petersen and Hawkins, D.E. and Dhuyvetter, D.V. and Ward, M. and Tovar, I. and Kris Havstad and Wallace, J.D.} } @article {51479, title = {Influence of ruminally dispensed monensin and forage maturity on intake and digestion}, journal = {Journal of Range Management}, volume = {46}, number = {3}, year = {1993}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {1993}, pages = {214-220}, abstract = {

Eight ruminally cannulated crossbred steers (average weight 336 kg) grazing native blue grama (Bouteloua gracilis\  [H.B.K.]) rangeland were used in a repeated measures design to evaluate effects of monensin ruminal delivery devices (MRDD) and forage phenology on ruminal digestion.\  Three periods were assessed: mid-August (Aug.), early October (Oct.), and mid-November (Nov.).\  One MRDD was placed in the reticulum of 4 steers via the ruminal cannula 21 days before each period.\  Intake was estimated using total fecal collections.\  Diet samples were collected using 3 esophogeally fistulated steers. Ruminal fill was measured by ruminal evacuation; rate and extent of in situ ruminal neutral detergent fiber disappearance were estimated before ruminal evacuations.\  Ruminal passage rates, retention time, and apparent total tract organic matter digestibility were estimated using indigestible neutral detergent fiber.\  In vitro organic matter disappearance of esophageal masticate did not differ (P\>.05) in Aug. and Oct. (average of 53.7\%), but declined (P\<.05) in Nov. (48.7\%), whereas organic matter digestibility was greater (P\<.10) in Aug. (62.3\%) than in either Oct. (55.2\%) or Nov. (53.9\%).\  Release of monensin from the bolus (68 mg day-1) was less than expected (100 mg day-1).\  Intake, organic matter digestibility, ruminal passage rates, retention time, pH, and ammonia were not affected (P\>.10) by MRDD.\  In situ neutral detergent fiber disappearance at 96 hours was decreased (P\<.10) by MRDD (68 vs 65\% for control and MRDD, respectively).\  As the grazing season progressed, intake declined (P\<.10), whereas ruminal fill and retention time increased (P\<.05), and passage rate of indigestible neutral detergent fiber decreased (P\<.05). At 48 hours in situ neutral detergent fiber was greatest (P\<.05) in Aug. and least (P\<.05) in Nov.

}, keywords = {beef, cattle, digestion, forage quality, rangeland}, url = {/files/bibliography/401.pdf}, author = {E.L. Fredrickson and Galyean, M.L. and Branine, M.E. and Sowell, B.F.} } @mastersthesis {51503, title = {Influences of range condition, cattle, and watering hole distribution on a pronghorn population in southcentral New Mexico}, year = {1993}, note = {//??//NONE//}, month = {1993}, pages = {130}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, mammal,pronghorn, pronghorn,resource distribution, theses, thesis}, author = {Sanchez, Fernando Clemente} } @mastersthesis {51507, title = {Influence of excellent and good condition Chihuahuan desert range on vegetation, cattle diets, and wildlife populations}, year = {1993}, note = {//??//NONE//}, month = {1993}, pages = {97}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {cattle,diet, dissertation, dissertations, rangeland, theses, thesis, vegetation, wildlife populations}, author = {Gretchen Tanner Smith} } @article {51536, title = {Inefficient nitrogen resorption in a population of ocotillo (Fouquieria splendens), a drought deciduous desert shrub}, journal = {Southwestern Naturalist}, volume = {37}, year = {1992}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1992}, pages = {35-42}, abstract = {Ocotillo is a drought-deciduous desert shrub capable of orchestrating rapid morphological and physiological adjustments to changes in environmental conditions. Lengths of over 2,500 stem segments from two populations of ocotillo growing in the Chihuahuan Desert were measured to explore the possibility that episodes of stem growth could be used to infer past environmental change. Stem growth was so intermittent and complex that historical projections of environmental conditions were not possible without first establishing benchmark stem segments. Once established though, benchmark stem segments and subsequent stem growth may be used as easily measurable integrators of ongoing environmental change in desert ecosystems.}, keywords = {article, articles, Fouguieria,nitrogen, journal, journals, nitrogen,Fouquieria, plant,Fouquieria, plant,ocotillo, Fouquieria}, author = {K.T. Killingbeck} } @article {51551, title = {The importance of subterranean termites in semi-arid ecosystems in south-eastern Australia}, journal = {Journal of Arid Environments}, volume = {22}, year = {1992}, note = {//OTHER//NONE//}, month = {1992}, pages = {87-91}, abstract = {

In mulga, Acacia aneura, woodland in north-western New South Wales, Australia, subterranean termites, constructed foraging galleries over organic debris, litter fragments, litter trains, dead wood, dead grass in perennial grass clumps and kangaroo and sheep dung. The larger quantities of litter, litter trains and dead wood in the mulga groves resulted in higher cover of termite gallery sheeting in this habitat, 6.56+-1.02\%, than in the intergrove erosion slopes, 2.2.8+-0.32\%. In the upper 20 cm of soil there were 52.1 storage galleries m-2. In mallee-spinifex habitats in south-western New South Wales, there was no evidence of subterranean termite feeding on dung or the dead stems of spinifex grass, Triodia iritans, but dead stems of mallee, Eucalyptus spp. were galleried and etched by termites. The numbers of sub-surface termite storage galleries in this habitat averaged 137.5 m-2. These galleries ranged between 4.5 and 49.0 cm3. These data suggest that subterranean termites in these Australian ecosystems may be more important as detritivores and in their effects on hydrological properties of soil than has been documented for subterranean termites in the Chihuahuan Desert of North America.

}, keywords = {article, articles, Australia,termites, decomposition,termite, journal, journals, termite,Australia}, doi = {10.1016/S0140-1963(18)30659-1}, url = {files/bibliography/92-JrnArdEnvnmnts-Whitford-2.pdf}, author = {Walter G. Whitford and J. Ludwig and J. Noble} } @mastersthesis {51561, title = {Influence of range condition on density and diet of black-tailed jackrabbits and diet of cattle in southcentral New Mexico}, year = {1991}, note = {//NMSU//NONE//}, month = {1991}, pages = {120}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, keywords = {cattle,diet, diet,Lepus, dissertation, dissertations, food habits,Lepus, lagomorph,diet,Lepus, Lepus,diet, theses, thesis}, author = {Alipayou Daniel} } @article {51577, title = {The influence of landscape position on temporal variability in four North American ecosystems}, journal = {American Naturalist}, volume = {138}, year = {1991}, note = {//??//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1991}, pages = {341-348}, abstract = {

The spatial setting of an ecosystem within a landscape influences many of the ecosystem{\textquoteright}s properties. Here, we ask whether there is a relation between the spatial positioning of different locations in a landscape and the annual variability exhibited at each location. We include data from four biome types represented in the Long-Term Ecological Research (LTER) network: northern Wisconsin lakes, Hubbard Brook Experimental Forest, the Jornada Desert, and the North Inlet estuary. At each LTER site, data on 26--68 ecological parameters have been collected at three to seven locations along an elevational gradient for at least 5 yr. We tested whether at each LTER site the annual variability exhibited by parameters at each location within the landscape was related to the location{\textquoteright}s relative elevation, that is, landscape position. Specific mechanisms relating spatial positioning to variability differed at the four LTER sites, but at each LTER site, (1) locations differed in the annual variability exhibited by ecological parameters, (2) for at least a subset of the parameters, this variability was related to the locations{\textquoteright} spatial positions, and (3) water movement across the landscape was the important underlying factor determining variability patterns. We conclude that landscape position influences the annual variability that ecosystems exhibit.

}, keywords = {article, articles, ecosystem, journal, journals, landscape position, temporal variability}, doi = {10.1086/285222}, url = {files/bibliography/JRN00143.pdf}, author = {T. K. Kratz and Benson, B. J. and Blood, E. R. and Gary L. Cunningham and Dahlgren, R. A.} } @mastersthesis {51641, title = {Influence of watering points and range condition on vegetation of the Chihuahuan desert}, year = {1990}, note = {//??//NONE//}, month = {1990}, pages = {127}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, grassland,range condition, grassland,watering points, rangeland,watering points, theses, thesis, watering points,effect on vegetation}, author = {Tembo, Ackim} } @mastersthesis {51642, title = {Interception of water by range plants and evaporation from soils in southwest New Mexico}, year = {1990}, note = {//??//NONE//}, month = {1990}, pages = {112}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, evaporation,soils, plants,water interception, theses, thesis, water interception,range plants}, author = {Vera-Cruz, Maria Teresa R. P.} } @mastersthesis {51656, title = {Individual plant response to grazing treatments on the College Ranch in southern New Mexico}, year = {1989}, note = {//NMSU//NONE//}, month = {1989}, school = {New Mexico University}, type = {M.S. Thesis}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, grazing management, theses, thesis}, author = {Chili, P. C.} } @article {51672, title = {Interplant variation in creosotebush foliage characteristics and canopy arthropods}, journal = {Oecologia}, volume = {81}, year = {1989}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1989}, pages = {166-175}, abstract = {

We conducted a field study to test the hypothesis that creosotebush (Larrea tridentata) shrubs growing in naturally nutrient-rich sites had better quality foliage and supported greater populations of foliage arthropods than shrubs growing in nutrient-poor sites. Nutrient-rich sites had significantly higher concentrations of soil nitrogen than nutrient-poor sites. Multivariate analysis of variance revealed significant differences between high nutrient and low nutrient shrubs based on a number of structural and chemical characteristics measured. High nutrient shrubs were larger, had denser foliage, greater foliage production, higher concentrations of foliar nitrogen and water, and lower concentrations of foliar resin than low nutrient shrubs. Numbers of foliage arthropods, particularly herbivores and predators, were significantly higher on high nutrient shrubs. Shrub characteristics and foliage arthropod abundances varied considerably from shrub to shrub. Shrub characteristics representing shrub size, foliage density, foliage growth, and foliar nitrogen and water concentrations were positively correlated with arthropod abundances. Foliar resin concentrations were negatively correlated with foliage arthropod abundances. The positive relationship between creosotebush productivity and foliage arthropods is contradictory to the tenet that physiologically stressed plants provide better quality foliage to insect herbivores.

}, keywords = {arthropod, Larrea, article, articles, journal, journals, Larrea, arthropods, Larrea, nitrogen, nitrogen, Larrea, phytophagous insect, plant-insect interactions}, doi = {10.1007/BF00379801}, url = {files/bibliography/JRN00099.pdf}, author = {David C. Lightfoot and Walter G. Whitford} } @article {51744, title = {Ion and sulfate-isotope ratios in arid soils subject to wind erosion in the southwestern USA}, journal = {Soil Science Society of America Journal}, volume = {52}, number = {1}, year = {1988}, note = {//NMSU, LOCAL//NONE, LTER//}, month = {1988}, pages = {54-58}, abstract = {

Our objective was to evaluate the potential for arid-land soil dusts to contribute significantly to the content of SO42- and other ions in precipitation. Soil samples collected at 102 location throughout southwestern USA deserts were extracted with distilled water and analyzed for major ionic constituents and the stable isotope ratios (34S/32S) in soluble sulfate. Most samples were dominated by Ca2+, and HCO3-, and were undersaturated with respect to gypsum. Only a weak correlation was found between Ca2+ and SO42- in samples from upland sites. Median 34 S of soil SO4 was +6.2\% compared to +3.9\% reported for precipitation. However, the median ratios for CA/SO4 (12.00) and Mg/SO4 (1.84) in soil extracts were much larger than the same ratios in precipitation, suggesting that wind erosion of undisturbed desert soils is not a major source of the SO4 in precipitation. Calcite aerosols from desert soils may act to neutralize acid rain in the western USA.

}, keywords = {acid rain, aeolian processes, article, articles, biogeochemistry, acid rain, biogeochemistry, calcite, biogeochemistry, gypsium, biogeochemistry, soil chemistry, biogeochemistry, stable isotopes, calcite, desert, gypsum, journal, journals, soil chemistry, stable isotopes}, doi = {10.2136/sssaj1988.03615995005200010010x }, url = {files/bibliography/JRN00082_0.pdf}, author = {W. H. Schlesinger and Peterjohn, William T.} } @article {51754, title = {Interactions among soil biota in desert ecosystems}, journal = {Agriculture, Ecosystems and Environment}, volume = {24}, year = {1988}, note = {//NMSU//LTER I//}, month = {1988}, pages = {87-100}, abstract = {

In desert systems, the availability of soil nitrogen can be the single most limiting factor controlling plant growth during periods of adequate soil moisture. Decomposition and nitrogen-mineralization rates prior to or during peak periods of plant growth can therefore be critical. Decomposition rates in deserts are generally high, and are relatively independent of rainfall. These high rates can be attributed to a combination of abiotic weathering, the types of microflora and microfauna associated with plant litter, and the adaptation of the soil biota to moisture pulses. The factors controlling litter decomposition and subsequent nitrogen mineralization are dependent upon the location of the organic matter in the habitat. The breakdown of surface litter occurs primarily through either abiotic weathering or by termite consumption. Microarthropods do not appear to have any role in the decomposition of surface litter owing to abiotic constraints on activity. The decomposition of roots, and buried litter, however, has been shown to be dependent on the presence of soil microarthropods. Microbial-microfaunal activity in the root region of desert plants may also have a significant effect on the short-term cycling of nitrogen in arid systems.

}, keywords = {article, articles, decomposition, abiotic factors, decomposition, microarthropods, decomposition, termites, decomposition, wood-rat middens, journal, journals, microarthropod,decomposition, nitrogen mineralization, rhizosphere, soil biota, termite,decomposition}, doi = {10.1016/0167-8809(88)90058-8}, url = {files/bibliography/JRN00081.pdf}, author = {J. C. Zak and Walter G. Whitford} } @mastersthesis {51761, title = {Influence of livestock grazing and protection from livestock grazing on vegetational characteristics of Bouteloua eriopoda rangelands}, year = {1987}, note = {//NMSU//NONE//}, month = {1987}, pages = {155}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {This study, conducted on Bouteloua eriopoda rangelands in southern New Mexico, was initiated in an attempt to quantify the effects of livestock grazing and protection from grazing on the vegetational characteristics of these ranges....Density and frequency of perennial and annual forbs, and shrubs showed no relationship to either protection or grazing. It was concluded that livestock grazing is an important management tool in maintaining Bouteloua eriopoda rangelands, probably due to the species low tolerance to, and slow recovery from, drouth when ungrazed.}, keywords = {cattle grazing, Bouteloua effect, dissertation, dissertations, grass, Bouteloua, rangeland,also SEE , rangeland,vegetation characteristics, theses, thesis}, author = {T.L. Atwood} } @conference {51770, title = {Increase in number of dominance-classes on a grassland in the northern Chihuahuan Desert}, booktitle = {40th Annual Meeting, Society for Range Management}, year = {1987}, month = {1987}, pages = {43}, author = {Gibbens, Robert P. and Reldon F. Beck} } @article {51771, title = {Increase in number of dominant plants and dominance-classes on a grassland in the northern Chihuahuan Desert}, journal = {Journal of Range Management}, volume = {40}, number = {2}, year = {1987}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {March 1, 1987}, pages = {136-139}, abstract = {

Between 1915 and 1932, 104 permanent 1x1-m quadrats were established on grasslands of the Jornada Experimental Range in southern New Mexico.\  Primary- and secondary-dominant species were determined from the first quadrat records and each quadrat was reevaluated in 1981 to determine current dominants.\  The first records showed that 13 species of perennial grasses occupied all primary- and secondary-dominant positions on all quadrats.\  In 1981, there were 12 perennial grass species as primary- or secondary-dominance.\  Six shrub species occurred as primary- or secondary-dominance on 47\% of the quadrat sites in 1981.\  Dominance-classes, i.e., single-species dominance or two-species dominant combinations, increased from 24 to 43.\  Thus, vegetation on this range has become more diverse and this diversity must be considered in grazing management.\ 

}, doi = {10.2307/3899205 }, url = {/files/bibliography/313.pdf}, author = {Gibbens, Robert P. and Reldon F. Beck} } @proceedings {51777, title = {Integration of mechanical control of unwanted plants and seeding equipment}, year = {1987}, month = {1987}, pages = {283-291}, abstract = {

This paper discusses principles and practices of mechanical control of unwanted plants and seeding rangelands, and how some practices are innovatively combined. Seeding methods discussed are use of rangeland drills, press drills, grain drills, trashy seed drills, broadcasting, one-way disk plow, arid-land seeder, chaining, the land imprinter, and range interseeder.

}, url = {/files/bibliography/316.pdf}, author = {C.H. Herbel} } @article {51786, title = {Gnathamitermes tubiformans (Isoptera: Termitidae), especie clave en el Desierto Chihuahuense}, journal = {Folia Entomol{\'o}gica Mexicana}, volume = {73}, year = {1987}, note = {//NMSU//NONE//}, month = {1987}, pages = {29-46}, abstract = {

(In Spanish with English abstract)

We demonstrate the importance of subterranean termites, especially Gnathamitermes tubiformans (Buckley), as a keystone species in the northern Chihuahuan Desert. They are the most important organism in the decomposition of organic matter, including cattle feces, wood and leaf litter. They are also important in the nitrogen cycle because they consume organic matter, fix atmospheric nitrogen, produce galleries rich in nitrogen and are prey for various predators. Their tunnels also increase the infiltration of water. Soil termites are sometimes considered pests due to competition with cattle for grass. We show that soil termites are essential in such areas because they open the soil for water infiltration and are essentially the only organisms that attack the cattle feces.

}, keywords = {article, articles, cattle dung, decomposition, decomposition, SEE , Isoptera, SEE , journal, journals, nitrogen,termites, termite,decomposition, termite,water infiltration, water infiltration, termites}, url = {files/bibliography/87-FoliaEntMex-Whitford.pdf}, author = {William P. MacKay and J. C. Zak and Solange Silva and Walter G. Whitford} } @article {51805, title = {Important factors influencing water infiltration and sediment production on arid lands in New Mexico}, journal = {Journal of Arid Environments}, volume = {12}, year = {1987}, note = {//OTHER//NONE//}, month = {1987}, pages = {111-118}, abstract = {

Factors influencing infiltration rates and sediment production were evaluated on representative study areas of four watersheds in New Mexico under various land management practices. Multiple regression analysis was used to determine the most important factors influencing infiltration and sediment production. Factors found important were soil texture, soil organic matter, soil bulk density, plant cover, biomass production, time to runoff and time to ponding. Of all variables studied, total ground cover was considered to be the most important single variable influencing infiltration and sediment production.

}, keywords = {article, articles, hydrology, infiltration, hydrology, sediment, journal, journals, sediment production, water infiltration}, url = {/files/bibliography/322.pdf}, author = {J. C. Wood and Wood, M. Karl and J.M. Tromble} } @article {51818, title = {The influence of subterranean termites on the hydrological characteristics of a Chihuahuan Desert ecosystem}, journal = {Oecologia}, volume = {68}, year = {1986}, note = {//NMSU//LTER I//}, month = {1986}, pages = {521-528}, abstract = {

Rainfall simulation at an average intensity of 124 mm.h-1 was used to compare infiltration and runoff on arid areas where subterranean termites had been eliminated four years prior to the initiation of the study (termite free) with adjacent areas populated by subterranean termites (termite present). Infiltration rates on termite free plots with less than 5\% perennial plant cover were significantly lower 51.3+-6.8 mm.h-1 than rates on comparable termites present plots 88.4+-5.6 mm.h-1. On plots centered on Larrea tridentata shrubs, there were no differences in infiltration rates with or without termites. Plots with shrub cover had the highest infiltration rates 101+-6 mm.h-1. Highest runoff volumes were recorded from termite free \<5\% grass cover plots and the lowest from plots with shrubs. There were no differences in suspended sediment concentrations from termites present and termite free plots. Average bed load concentration was more than three times greater for termite free, \<5\% cover plots than from termite present, \<5\% cover plots. The reduction in infiltration, high runoff volumes and high bedloads from termite free areas without shrub cover is relatd to increased soil bulk density resulting from the collapse of subterranean galleries of the termites that provide avenues of bulk flow into the soil. Subterranean termites affect the hydrology of Chihuahuan desert systems by enhancing water infiltration and retention of top soil. The presence of a shrub canopy and litter layer cancels any effect of subterranean termites on hydrological parameters. Since approximately 2/3 of the area is not under shrub canopies, subterranean termites are considered to be essential for the maintenance of the soil water characteristics that support the present vegetation.

}, keywords = {article, articles, hydrology, termite effects, journal, journals, Larrea, termites, Larrea,hydrology, pesticide,Chlordane, rainfall simulation, termite effects, shrub, creosotebush,Larrea, termite,hydrology effects}, doi = {10.1007/BF00378766}, url = {files/bibliography/JRN00045.pdf}, author = {Ned Z. Elkins and Sabol, George V. and Timothy J. Ward and Walter G. Whitford} } @article {51870, title = {Improved esophageal fistula closure devices for cattle and sheep}, volume = {Agricultural Research Service, ARS-26}, year = {1985}, month = {1985}, pages = {20}, institution = {U.S. Department of Agriculture, Agricultural Research Service}, abstract = {This publication describes a redesigned esophageal fistula plug and an esophageal cannula. These closure devices set forth state-of-the-art structural design, are more rugged, require minimal time to construct, and are relatively light when compared with previous esophageal fistula closure devices. In addition, the redesigned fistula closure devices are reliable in use and easily adapted to animal necks of various depths. The design of the fistula plug for use in cattle and sheep, along with the design for an esophageal cannula for use in cattle, are discussed and fabrication plans are included.}, keywords = {cannulas, esophageal fistula, livestock diets, plugs}, url = {/files/bibliography/273.pdf}, author = {D.M. Anderson and Mertz, D.L. and Franklin, W.E. and Manz, P.J.} } @conference {51873, title = {Influence of long-term protection from livestock grazing on basal cover of perennial grasses and canopy cover of shrubs on black grama rangelands in southern New Mexico}, booktitle = {38th Annual Meeting, Society for Range Management}, year = {1985}, month = {1985}, pages = {No. 155}, keywords = {basal cover, black grama, grazing, livestock, perennial grasses, protection, rangelands}, author = {T.L. Atwood and Reldon F. Beck and Gibbens, Robert P.} } @mastersthesis {51891, title = {Implications of rodent and rabbit grazing in the Chihuahuan Desert}, year = {1985}, note = {//NMSU//LTER I//}, month = {1985}, pages = {35}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Effects of rodent and rabbit grazing on percent plant cover were examined using a series of 50 exclosed and 50 unexclosed 0.25-m2 plots along two parallel transects in southern New Mexico beginning in May 1984 and ending in March 1985. Excluding rodents and rabbits from experimental plots resulted in significantly more vegetative cover within exclosures. Plots located along a treatment transect which had been fertilized with ammonium nitrate in August 1983 and March 1985 had a greater percentage of vegetative cover than plots along a control transect, both inside and outside the exclosures. Acting as physical barriers, exclosures prevented mammals and ground-dwelling arthropods from consuming and trampling vegetation and from harvesting seeds. No utilization of the vegetation as forage, in addition to a possible seed reserve within exclosed plots, from which germinants could grow, explains the presence of more vegetation within exclosed plots. This study provides a quantitative measure of rodent- and rabbit-grazing effects on vegetative cover, which is a necessary step in the development of a predictive model of the dynamics of desert rodent populations.}, keywords = {dissertation, dissertations, grazing, nitrogen amendment, grazing, rabbit, grazing, rodent, rabbit,grazing, rodent,grazing, theses, thesis, transect, herbivory, transect, nitrogen amendment, transect, rabbit grazing, transect, rodent grazing, transect,rodent \& rabbit grazing}, author = {Matheys, David G.} } @inbook {51956, title = {Increasing market lamb production efficiency}, booktitle = {Sheep and Goat Handbook}, year = {1983}, month = {1983}, pages = {407-415}, publisher = {Winrock International, Westview Press}, organization = {Winrock International, Westview Press}, address = {Boulder, CO}, abstract = {

Lamb production efficiency should be measured in relation to the total pounds of lamb meat produced per pound of feed consumed by the entire flock. The quality and cost of feed consumed by the entire flock. The quality and cost of that feed also must be considered.\  These assumptions imply that for greatest lamb-production efficiency--every female in the flock should begin production as early in life as possible and produce lambs as rapidly as management constraints permit. Lambs should be fed until efficient gains stop.

Four practices that can have a great impact on improving efficiency are: 1) breeding ewes to lamb at 1 year of age, 2) producing more twins, 3) improving rate and efficiency of gain, and 4) producing larger lambs.

}, url = {/files/bibliography/240.pdf}, author = {Clarence V. Hulet and Ercanbrack, S.K.}, editor = {Baker, F.H.} } @mastersthesis {51961, title = {Influence of mesquite on vegetational changes under two grazing strategies in southern New Mexico}, year = {1983}, note = {//NMSU//NONE//}, month = {1983}, pages = {61}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Seasonal suitability and continuous yearlong grazing systems were initiated in 1967 on desert rangeland on the College Ranch in southern New Mexico. Cover, composition and production were measured on 220 permanent transects in 1968 and 1982. Herbicide was applied to mesquite (Prosopis glandulosa) between 1958 and 1964 on extensive areas of the study pastures. Mesquite cover and density were significantly lower (P<.10) in the herbicide-treated areas than in the nontreated areas in 1982. Between herbicide treatments and years black grama (Bouteloua eriopoda) and dropseed (Sporobolus spp.) cover did not increase significantly (P>.10). Threeawn (Aristida spp.) cover increased (P<.10) between 1968 and 1982 in nontreated areas. The principle of the seasonal suitability system is to provide a grazing system for areas in which different vegetation types and range condition classes are found. Data indicated that the seasonal suitability system did not prove superior to yearlong grazing in areas of varied vegetation and range condition.}, keywords = {cattle, grazing strategies, dissertation, dissertations, grazing strategies, mesquite, grazing strategies, mesquite, vegetation changes, plant,Prosopis, Prosopis, vegetation change, rangeland, grazing strategies, rangeland, influence of mesquite, theses, thesis, vegetation change,mesquite influence}, author = {R.P. McNeely} } @article {51968, title = {Interactions in microhabitat use between Dipodomys ordii and Onychomys leucogaster}, journal = {Ecology}, volume = {64}, number = {5}, year = {1983}, note = {//NMSU//NONE//}, month = {1983}, pages = {984-988}, abstract = {Hypotheses attempting to explain structure in desert rodent communities have emerged primarily from studies dealing with heteromyid interactions. Little attention has been given to the cricetid elements in the community, despite their often high densities and year-round activity in close association with heteromyid species. This study extends the understanding of desert rodent community dynamics by examining interactions in microhabitat use between Dipodomys ordii (Heteromyidae) and Onychomys leucogaster (Cricetidae). Research was designed to test the hypothesis: in a two-species (experimental) enclosure, microhabitat use by each species will not differ from that in one-species (control) enclosures. Results indicate that D. ordii shifts microhabitat use when co-occurring with O. leucogaster, while the reverse does not occur. This outcome shows that interactions are operating between these two species. Further, studies aimed at determining presumed structure among desert rodent species may be lacking information on significant nonheteromyid elements of the community.}, keywords = {article, articles, community structure, microhabitat shifts, competition,rodents, Dipodomys, enclosure experiment, history,enclosure, journal, journals, Onychomys, rodent, Dipodomys, rodent,assemlages, rodent,microhabitat shifts, rodent,Onychomys}, author = {Cindy Rebar and W.H. Conley} } @proceedings {51976, title = {Interception by creosotebush and tarbush}, year = {1983}, month = {1983}, author = {J.M. Tromble} } @article {51978, title = {Interception of rainfall by tarbush}, journal = {Journal of Range Management}, volume = {36}, number = {4}, year = {1983}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {July 1, 1983}, pages = {525-526}, abstract = {

The objective of this study was to determine the interception by tar bush of artificially applied rainfall. Twelve tarbush shrubs were collected near Las Cruces in southern New Mexico to obtain a representative sample of shrub size classes. Simulated rainfall was applied at the rate of 6 cm/hr for 30 min. Canopy cover of the tarbush community was determined from 10 line intercept transects 30.48 m long. A stepwise regression analysis using the minimum R 2 \ improvement technique was used to examine the effects of plant parameters on interception. The "best" one variable model was shrub green weight, which accounted for 75\% of the variability of the intercepted rainfall. Extrapolating the calculated interception of artificially applied rainfall to the native stand of tarbush with 15.2\% canopy cover indicated that 0.5 mm of rainfall would be intercepted from a 30 mm rainfall event. Disregarding rainfall events of less than 3.0 mm, an average of 8.5 mm of rainfall would be intercepted by the tarbush community or 6. 7\% of the average rainfall from May through October.

}, url = {/files/bibliography/251.pdf}, author = {J.M. Tromble} } @conference {51984, title = {Infiltration and runoff water quality of selected sites within four critical yield watersheds: A hydrologic assessment of land use practices in New Mexico}, booktitle = {19th Annual Meeting of the American Water Resources Association}, year = {1983}, month = {1983}, address = {San Antonio, TX}, author = {J. C. Wood and Wood, M. K. and J.M. Tromble} } @article {52011, title = {Impact of borrowing activity of the bannertail kangaroo rat on southern New Mexico desert rangeland}, journal = {Journal of Range Management}, volume = {35}, number = {6}, year = {1982}, note = {//NMSU//NONE//}, month = {1982}, pages = {707-710}, abstract = {The impact of burrowing activity of the bannertail kangaroo rat (Dipodomys spectabilis) on southern New Mexico desert rangelands was investigated. The study was conducted on black grama (Bouteloua eriopoda), dropseed (Sporobolus spp.) and mesquite (Prosopis glandulosa) grassland vegetation types. Mound density was highest in the black grama type, somewhat intermediate in the dropseed type, and lowest in the mesquite-grassland type. The surface area occupied by mounds averaged 2\% over all vegetation types in the study area. Plant cover was generally greater off mounds than on mounds. Annual plant cover was greater on mounds than off mounds, suggesting that activities of bannertail kangaroo rats promote the presence of annuals.}, keywords = {article, articles, bannertail kangaroo rat, SEE , burrowing activity,Dipodomys, Dipodomys, journal, journals, management,Dipodomys, rangeland,Dipodomys, rodent, Dipodomys, burrowing activity, rodent, Dipodomys, rangeland impact, rodent,bannertail kangaroo rat}, author = {Moroka, Neo and Reldon F. Beck and Pieper, Rex D.} } @proceedings {52061, title = {Interception of rainfall by creosotebush}, year = {1981}, month = {1981}, pages = {373-375}, address = {Lexington, KY}, url = {/files/bibliography/208.pdf}, author = {J.M. Tromble} } @proceedings {52060, title = {Interception of rainfall by creosotebush (Larrea tridentata)}, volume = {Section 5}, year = {1981}, note = {//LOCAL//NONE//ProCite field[6]: In}, month = {1981}, pages = {373-375}, abstract = {

The objective of this study was to examine interception by creosotebush (Larrea tridentata [DC.] Cov.) of artificially applied rainfall for improved understanding of this phenomenon in hydrologic processes. This research was conducted near Las Cruces in southern New Mexico.... It was determined that leaf area was most highly correlated with rainfall interception, followed by number of stems, crown canopy area, and weight of over-dry leaves..... The annual rainfall in the southwestern U.S.A. is produced from storms of small amounts. Thus, interception by desert shrubs is of significant importance, since a high percentage of precipitation from these storms is "lost" from interception and subsequent evaporation back into the atmosphere. Twenty percent of the artificially applied rainfall was intercepted by creosotebush. For the native stands of creosotebush that had 30\% crown cover, the loss of rainfall by interception would equal 22\%. These data clearly demonstrate that light showers (\<5 mm) do little to replenish soil water.

}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, hydrology, rainfall interception,Larrea, Larrea,rainfall interception, proceeding, proceedings, rainfall interception,Larrea, rainfall simulation,Larrea}, url = {/files/bibliography/208.pdf}, author = {J.M. Tromble} } @article {52095, title = {Importance of Forbs on Southwestern Ranges}, journal = {Rangelands}, volume = {2}, number = {1}, year = {1980}, month = {1980}, pages = {35-36}, abstract = {Forbs, as a class of range plants, are often looked upon with disfavor when they occur on rangelands. There is good reason for this unfavorable view of forbs. Many forbs are opportunistic and do invade disturbed areas. If vigor of grasses is lowered by heavy grazing, forbs often incresae. Because of this phenomenon many range managers consider ranges with abundant forbs to be deteriorated. Some of thse forbs may be poisonous and can creste additional problems for livestock operators. With this reputation, it is not surprising that forbs have not ben held in high favor among some livestock operators and range workers in the past.}, keywords = {forbs, rangeland, ranges}, url = {/files/bibliography/108.pdf}, author = {Pieper, Rex D. and Reldon F. Beck} } @mastersthesis {52096, title = {Interactions in microhabitat use between Dipodomys ordii and Onychomys leucogaster}, year = {1980}, note = {//NMSU//NONE//}, month = {1980}, pages = {41}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Hypotheses attempting to explain structure in desert rodent communities have emerged primarily from studies dealing with heteromyid interactions. Little attention has been given to the cricetid elements in the community despite their typically high densities and year-round activity in close association with heteromyid species. This study extends the understanding of desert rodent community dynamics by examining interactions in microhabitat use between Dipodomys ordii (Heteromyidae) and Onychomys leucogaster (Cricetidae). Research was designed to test the hypothesis: In a 2-species (experimental) enclosure, microhabitat use by each species will not differ from that in 1-species (control) enclosures. Results indicate that D. ordii shifts microhabitat use when co-occurring with O. leucogaster, while the reverse does not occur. This outcome shows that interactions are operating between these 2 species. Further, studies aimed at determining structure and elucidating patterns in desert rodent communities may be lacking information on significant nonheteromyid elements of the community.}, keywords = {community structure, microhabitat shifts, competition,rodents, Dipodomys, dissertation, dissertations, enclosure experiment, history,enclosure, Onychomys, rodent, Dipodomys, rodent,microhabitat shifts, rodent,Onychomys, theses, thesis}, author = {Cindy Rebar} } @article {52110, title = {Infiltration rates on rootplowed rangeland}, journal = {Journal of Range Management}, volume = {33}, number = {6}, year = {1980}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {November 1, 1980}, pages = {423-425}, abstract = {

Infiltration and \ runoff \ from \ mechanically \ treated \ arid South- western rangeland \ were measured. Control plots dominated by creosotebush \ had greater infiltration rates than the 1972 and 1976 rootplowed \ and \ seeded \ treatments, stressing \ the \ importance of cover for reducing runoff and controlling erosion.Infiltration rates on dry soils were significantly higher on the 1972 rootplowed and seeded treatment compared \ with the 1976 rootplowed \ and seeded treatment, \ indicating\  \ the \ lack\  \ of \ soil \ structure \ in \ the \ 1976 treatment.

}, url = {/files/bibliography/186.pdf}, author = {J.M. Tromble} } @article {JRN54842, title = {Improving reproductive efficiency in sheep}, year = {1978}, abstract = {

The efficiency of lamb production can be improved by overcoming the major reproductive problems of sheep: (a) low lambing rate; (b) restricted breeding season; (c) low fertility during the early postpartum period; (d) late puberty; and (e) perinatal lamb losses.

Lambing rate is being improved impressively by increasing the ovulation rate through crossbreeding., selection, and improved management. Little progress has been made in reducing embryonic and fetal mortality, a problem especially prevalent during the early part of the breeding season and in hot environments. Some progress is being made toward reducing the restrictions to lamb production efficiency caused by the short breeding season. The breeding season is being eliminated, lengthened, or modified through breeding and selection hormone therapy and controlling exposure to light. Much more needs to be done to permit lambing at any time of year and to shorten lambing intervals to less than one year.

Little progress has been made in improving fertility during the early postpartum interval. This an important area for future investigation in order to shorten lambing intervals. Age at puberty has been reduced and fertility improved in ewe lambs through crossbreeding, selection, improved nutrition, and management. The breeding of ewe lams is commonly practiced throughout the United States with increasing success every year. New research data in management and disease control suggest success each year. New research data in management and disease control suggest way to markedly reduce losses of perinatal lambs. Further progress may come through the development of new vaccines for the prevention of losses caused by enzootic abortion in ewes and scours in lambs.

}, keywords = {Improving reproductive efficiency, sheep}, author = {Clarence V. Hulet} } @proceedings {52168, title = {Infiltration rates on rootplow-treated rangeland}, volume = {59}, year = {1978}, month = {1978}, pages = {1071}, keywords = {infiltration rates, rangeland, rootplow treated}, author = {J.M. Tromble} } @proceedings {52183, title = {Improving production from arid rangelands of the southwestern United States}, year = {1977}, month = {1977}, pages = {625-628}, address = {Leipzig, GDR}, abstract = {Three methods of several possibilities are discussed for improving production from arid rangelands. Sandy lands infested with mesquite can be improved by aerially spraying with 2,6,5-T. Natural recovery of perennial grasses, primarily mesa dropseed, following spraying resulted in 204 kg/ha herbage compared to 33 kg/ha on the adjacent unsprayed area. An area infested with creosotebush was root-plowed and seeded. Herbage production in 1975 was 1,631 kg/ha, primarily Lehmann and Boer lovegrass. Cattle production was increased by crossbreeding Herefords with either Brangus or Santa Gertrudis. The weaning weights of Santa Gertrudis calves were heavier than calves from the other two breeds, but the conception rate was higher for the Brangus cows. Calf production per cow was about 50\% greater from the crossbred dams than from the Hereford dams.}, keywords = {aerial spraying, arid rangelands, crossbreeding, improving production, Southwest}, url = {/files/bibliography/160.pdf}, author = {C.H. Herbel and Gibbens, Robert P. and J.M. Tromble} } @conference {52226, title = {Improved Range Plants}, booktitle = {Society for Range Management, Range Symposium Series, No. 1}, year = {1975}, month = {1975}, pages = {96 pp}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Denver, CO}, abstract = {

Improved Range Plants in Resource Management is the first in a new numbered series of range symposia to be published by the Society for Range Management. One or more symposia have been presented at each of the 28 Annual Meetings of the Society, but publication of the papers has been highly variable. A few complete symposia have been published in the Journal of Range Management or in separate bound volumes; many individual symposium papers have been published in the Journal. This group of papers on improved range plants is a worthy choice to introduce the new series. We trust that the Society will continue to publish timely and informative symposia in the future.

}, url = {/files/bibliography/156.pdf}, author = {R.S. Campbell and C.H. Herbel} } @article {JRN54643, title = {Identification of cotton haploids by Stomatal Chloroplast-count technique}, journal = {Crop Science}, volume = {15}, year = {1975}, month = {11/1975}, pages = {760-763}, chapter = {760}, abstract = {

Chloroplast counts were made from the stomatal guard cells in haploid (n {\textemdash} 2x {\textemdash} 26) and in natural tetraploid (2n = 4x {\textemdash} 52) plants of Gossypium hirsutum L. and G. barbadense L. The mean chloroplast number was 10.46 {\textpm} 2.18 for haploids and 21.00 {\textpm} 3.31 for tetraploids.\  The means from haploid plants did not overlap with the means from tetraploid plants in 280 plants evaluated. Cotton plants can be classified much easier and quicker from the cotyledon stage to maturity as haploids or tetraploids and as accurately as by chromosome counts.

}, url = {/files/bibliography/Barrow 1975 Crop Sci Identification of Cotton......pdf}, author = {H. K. Chaudhari and J.R. Barrow} } @article {52237, title = {Influences of temperature and humidity on oxygen consumption of five Chihuahuan desert ants}, journal = {Comparative Biochemistry and Physiology}, volume = {52A}, year = {1975}, note = {//NMSU//US-IBP//}, month = {1975}, pages = {281-286}, abstract = {

1. Oxygen consumption in five sympatric species of Chihuahuan desert ants was measured at three relative humidities at 15, 25 and 35\°C.

2. The rate of oxygen consumption (QO2) exhibited non-linear increase in Formica perpilosa, Pogonomyrex desertorum, Novomessor cockerelli and Trachymyrmex smithi neomexicanus, but was linear in Pogonomyrmex californicus.

3. Vapor pressure deficit had a significant effect on QO2 of P. desertorum, T. s. neomexicanus and F. perpilosa but not on the other two species.

4. Activity increased at higher vapor pressure deficits in P. desertorum, N. cockerelli and T. s. neomexicanus.

5. The highest vapor pressure deficits at 35\°C resulted in deaths of all species except P. californicus and T. s. neomexicanus died at intermediate and high vapor pressure deficits at all temperatures.

}, keywords = {ant, Formica, ant, humidity, ant, Novomesser, ant, oxygen consumption, ant, physiology, ant, Pogonomyrmex, ant, temperature, ant, Trachymyrmex, article, articles, journal, journals}, doi = {10.1016/S0300-9629(75)80087-9}, url = {files/bibliography/75-ComBioPhs-Whitford.pdf}, author = {Carol Ann Kay and Walter G. Whitford} } @article {52254, title = {The impact of consumers in a desert ecosystem}, year = {1975}, note = {//??//US-IBP//}, month = {1975}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {book, books, chapter, chapters, consumers, report, reports}, isbn = {Research Memorandum 75-22}, author = {Walter G. Whitford} } @article {52261, title = {The influence of soil water potential on the perennial vegetation of a desert arroyo}, journal = {The Southwestern Naturalist}, volume = {19}, number = {3}, year = {1974}, note = {//LOCAL//NONE//}, month = {1974}, pages = {241-248}, abstract = {The density, mean plant height and mean plant width of the perennial shrubs in a desert arroyo were compared with the soil water potential gradient along the arroya during one growing season. The data indicated that the density of shrubs was negatively correlated with the soil water potential gradient and shrub mean size positively correlated with the gradient. The variation in the vegetation parameters could not be accounted for by the soil water potential gradient alone.}, keywords = {arroyo,influence of soil water, article, articles, journal, journals, shrub, arroyo soil water, soil, arroyo water potential}, author = {F. R. Balding and Gary L. Cunningham} } @article {52268, title = {Invertebrate studies at the Jornada site, 1972}, year = {1974}, note = {//USDA//US-IBP//}, month = {1974}, institution = {Colorado State University}, address = {Ft. Collins, Colorado}, keywords = {book, books, chapter, chapters, invertebrates, report, reports}, isbn = {Technical Report 242}, author = {M. A. Ellstrom} } @mastersthesis {52276, title = {Influence of the burrow environment on body temperature, oxygen consumption and water loss of the banner-tailed kangaroo rat, Dipodomys spectabilis}, year = {1974}, note = {//NMSU//NONE//}, month = {1974}, pages = {99}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {1. The 21 Dipodomys spectabilis used in the study had a mean body mass of 146.7 g. The animals were maintained in natural burrows, artificial burrows or the laboratory. In the laboratory body temperature, oxygen consumption and evaporative water loss were measured as they responded to burrow temperature, water vapor pressure and CO2 concentrations.1.}, keywords = {Dipodomys, physiology, dissertation, dissertations, rodent, Dipodomys, rodent, metabolism, rodent, physiology, theses, thesis}, author = {F. R. Kay} } @article {52302, title = {Improving arid rangelands}, year = {1973}, month = {1973}, pages = {16 }, abstract = {The productivity of arid rangelands has been greatly reduced by droughts, a rapid increase of noxious shrubs and improper grazing. An increase of brush is responsible for the loss of grazing lands that formerly contributed significantly to the production of livestock and wildlife. As undesirable shrubs increase, there is a corresponding loss of protective forage species and an increase in wind and water erosion. Drought periods are frequent and expected. We must consider fluctuating moisture conditions in all decisions involving arid rangelands because this resource is easily damaged by abuse. Even when the source of abuse is removed, improvement is often very slow. Arid rangelands are very fragile and must be handled accordingly. The objective of this paper is to discuss some of the problems in managing arid rangelands and to discuss methods for maintaining or improving the resource. The area under discussion is southeastern Arizona, southern New Mexico, western Texas, and northern Mexico.}, keywords = {arid rangelands, droughts, government publication, improper grazing, improvement, management problems, productivity}, url = {/files/bibliography/144.pdf}, author = {C.H. Herbel and W. L. Gould} } @proceedings {52304, title = {Improving arid rangelands}, year = {1973}, month = {1973}, address = {Mexico D.F.}, author = {C.H. Herbel and W. L. Gould} } @article {52349, title = {Intensity of foraging activity as a function of temperature, humidity, light, food availability, and soil moisture in a desert ecosystem}, year = {1972}, note = {//??//US-IBP//}, month = {1972-73}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {book, books, chapter, chapters, foraging activity,abiotic factors, foraging activity,food availability, report, reports}, isbn = {Research Memorandum 72-32, 73-29, 73-32.}, author = {Walter G. Whitford} } @article {52401, title = {Influence of grazing intensity on improvement of deteriorated black grama range}, year = {1970}, note = {//USDA//NONE//}, month = {1970}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, abstract = {The objective of the work reported in this bulletin was to determine the level of use of black grama that will permit satisfactory recovery of deteriorated range.}, keywords = {book, books, Bouteloua, grazing, cattle grazing, Bouteloua, chapter, chapters, grassland, grazing intensity, grassland,productivity, management,Bouteloua, productivity,Bouteloua, report, reports}, isbn = {Bulletin 553}, author = {Valentine, K. A.} } @mastersthesis {52435, title = {Intake and digestability of range forage by Hereford and Santa Gertrudis cows}, year = {1968}, note = {//NMSU//NONE//}, month = {1968}, pages = {61}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Intake and digestibility of range forage in three different months by Hereford and Santa Gertrudis cows were estimated using chromic oxide in shredded paper administered every other day as an external indicator for the determination of fecal output and lignin as an internal indicator for estimating forage digestibility.}, keywords = {cattle, food habits, cattle, nutrition, dissertation, dissertations, food habits, cattle, range forage, theses, thesis}, author = {Hills, Jack Myron} } @mastersthesis {52437, title = {Intake and digestibility of tobosa (Hilaria mutica) by grazing steers}, year = {1968}, note = {//USDA//NONE//}, month = {1968}, pages = {91}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Esophageal-fistula samples of dormant tobosa (Hilaria mutica (Buckl.) Benth.) contained significantly more silica, ash protein, ether extract, detergent fiber and detergent lignin, abut less A.O.A.C. fiber than hand-plucked grass samples collected in each of seven pastures used in grazing studies at the Jornada Experimental Range. Except for ash, the differences were apparently due to selective grazing by the steers.}, keywords = {cattle grazing, Hilaria, cattle, nutrition, dissertation, dissertations, Hilaria, also SEE , theses, thesis}, author = {H.E. Kiesling} } @article {JRN54843, title = {Induction of Fertile Estrus in Lactating and Dry Anestrous Ewes Using Oral Progestogens and Repeated PMS Treatment}, journal = {Journal of Animal Science}, volume = {26}, year = {1967}, month = {1967}, pages = {545-548}, chapter = {545}, abstract = {

Mature ewes of predominately Columbia type were used to determine the effects of two oral progestogens, 6-chloro-Δ6-17 acetoxy-progesterone (CAP) and 6-methyl-17-acetoxy-progesterone (MAP), and PMS on fertility in lactating and nonlactating (early weaning) ewes. The 184 lactating ewes were randomized into three treatment series. The two different oral progestogens were used in series 1 and 2. MAP was used in series 3. Series 1 received two short progestogen treatments (3 and 8 days) each followed by PMS 24 hr. later. Series 2 received a long progestogen treatment (14 days) followed by PMS 1 and 17 days later. Series 3 was like series 2, except that MAP was given again for 3 days before the second PMS. Forty-one ewes from the early-weaning group were also randomized into the series 1 and 2 treatments. Treatment started March 19 when the lambs were 30 to 90 days of age.

Only 4\% of the treatment-1 series lactating ewes were marked by fertile rams following the first PMS as compared to 54\% of the treatment-2 series lactating ewes (P\<.01). Eighty-six percent in the treatment-1 series showed estrus following both PMS injections. Other estrous data were unreliable and excluded.

There was no significant effect of kind of progestogen or of lactation on percent of ewes lambing and of lambs at 2 weeks postpartum, but there was a significant effect of the length of the progestogen treatment before the first PMS on both variables. A comparison of the response of lactating ewes in treatment series 3 with treatment series 2 appears to indicate that there is a definite advantage in repeating the treatment with PMS irrespective of the occurrence of heat. A comparison of the treatment-1 and -2 series indicates that there is little or no detrimental effect of PMS on established pregnancies. The ewes lambing in the treatment-2 series had a higher percentage of lambs alive at about 14 days postpartum than the treatment-1 and treatment-3 series (128\%, 97\% and 100\%, respectively).

}, keywords = {Dry Anestrous, ewes, Induction of Fertile Estrus, Lactating, Oral Progestogens, Repeated PMS Treatment}, doi = {10.2527/jas1967.263545x}, url = {https://dl.sciencesocieties.org/publications/jas/pdfs/26/3/JAN0260030545}, author = {Clarence V. Hulet and W.C. Foote} } @article {52497, title = {Influence of location and season on the composition of New Mexico range grasses}, year = {1964}, note = {//??//NONE//}, month = {1964}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, chapter, chapters, grass,composition, grassland,composition, report, reports}, isbn = {Bulletin 486}, author = {Watkins, W. E. and Repp, W. W.} } @article {52504, title = {Insects associated with black grama grass, Bouteloua eriopoda}, journal = {Annals of the Entomological Society of America}, volume = {56}, year = {1963}, note = {//NMSU//NONE//}, month = {1963}, pages = {374-379}, abstract = {Collections from black grama grass, Bouteloua eriopoda Torrey, were made throughout the year by a variety of techniques, on a ranch in southern New Mexico, and 9 orders, 55 families, 109 genera, and 120 species of insects were taken. They included grass feeders, parasites and predators, and casual visitors. Four species of Thysanoptera accounted for considerably more than 50\% of the total insect population and 97\% of the thrips were Chirothrips falsus Hood. Insect populations were translated by use of broad-spectrum insecticides. The reproduction of the C. falsus population by 80\% or more resulted from consistent and substantial increase in seed set which in a few cases, increased 6 or 7 times. Other insects were at such low levels that no significant change in their numbers could be measured.}, keywords = {article, articles, Bouteloua, seed development, Bouteloua,insects, insect, associated with Bouteloua, insecticide,Bouteloua, journal, journals, list, Bouteloua insects}, author = {Watts, J. G.} } @mastersthesis {52517, title = {Increase of mequite on a southern New Mexico desert grassland range}, year = {1960}, note = {//USDA//NONE//}, month = {1960}, pages = {55}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {The encroachment of mesquite onto the desert grasslands of the Southwest has reduced the carrying capacity of a considerable portion of these grasslands. The purpose of the present study is to supply some of the information that will supplement studies concerned with the improvement of mesquite-infested ranges. Grazing by domestic livestock, climatic change, and suppression of grassland fires are each considered as a possible primary cause of the increase of mesquite on the Jornada Plains. The author concludes that grazing by domestic livestock, and the associated mesquite seed dissemination, was the most likely of the three factors to have disrupted the balance and allowed mesquite to extensively invade this area.}, keywords = {brush control,Prosopis, cattle, Prosopis distribution, dissertation, dissertations, Prosopis, cattle, Prosopis, distribution, theses, thesis}, author = {Robert Anderson Wright} } @article {52550, title = {Inorganic blood phosphorus levels necessary for satisfactory production of range cattle in the southwest}, journal = {Journal of Animal Science}, volume = {3}, year = {1948}, note = {//??//NONE//(New Mexico Agr. Experiment Station Journal Article 46)//}, month = {1948}, pages = {263-272}, keywords = {article, articles, cattle,biochemistry, cattle,phosphorus, journal, journals, nutrients,cattle, phosphorous,cattle, production,cattle}, author = {Watkins, W. E. and Knox, J. H.} } @article {52612, title = {The influence of precipitation and grazing upon black grama grass range}, year = {1934}, month = {April 1934}, pages = {32 }, abstract = {The excellent stand and growth of palatable perennials that once covered much of the semiarid rangelands of the Southwest afforded abundant feed for a thriving livestock industry. Where such conditions still prevail and management is adjusted to sustain production of feed within the limits of climatic conditions, livestock production is effective. On most of the range, however, continued over-stocking and the consequent accumulation of ill effects of overgrazing, combined with recurring drought, have brought about conditions involving not only heavy losses to the livestock producer but even a complete failure of profitable production. How to restore the productivity of these lands is an urgent question and one with many ramifications. One very important consideration is the preservation of the best of the remaining forage and the extension of its present growth. In this connection, one species of perennial grass growing on a considerable part of the semidesert range deserves primary attention. This is both because of its high palatability and its ability to extend its growth abundantly under moderately favorable circumstances, in which particulars black grama (Bouteloua eriopoda) is without a peer. Originally, black grama was the mainstay of the range, occurring rather abundantly and in almost a pure type over extensive areas of southeastern Arizona, southern New Mexico, western Texas, and south into Mexico. As such stands deteriorated, black grama died out to a considerable degree, but the plant still occurs as important range forage on extensive areas either in almost pure stands or mixed with other perennial grass species. Black grama is characteristically drought resistant, a quality indispensable to the maintenance of any range forage plant under the climatic conditions prevailing in the Southwest. It is highly palatable and nutritious both in summer and winter, making it a valuable year-long forage plant, especially for cattle. During some winters, the stems remain green up to about the second node from the top, and clusters of leaves may come out at the nodes the following spring. Black grama ordinarily cures well on the stalk and retains its nutritive value through the dry spring period when other range forage is parched and harsh. Although the plant can withstand recurrent grazing by livestock, too heavy utilization impairs its vigor. During drought periods, plants so weakened succumb, thereby greatly depleting the stand. It is of the greatest importance, therefore, to know just what degree of grazing use can be applied without injury to black grama ranges. This bulletin presents the results 13 years of study (1915 to 1927, inclusive) of the influence of the variable precipitation and several intensities of grazing on the black grama range type on the Jornada Experimental Range (formerly Jornada Range Reserve) and adjacent public domain range in southern New Mexico. The adoption on southwestern ranges of such principles as this study has brought to light should make the range cattle business of the region much more stable and profitable.}, keywords = {black grama, government publication, grazing, overgrazing, precipitation, range forage}, url = {/files/bibliography/028.pdf}, author = {Nelson, E. W.} } @article {52627, title = {An improved pair of shears for clipping studies on quadrats}, journal = {Ecology}, volume = {9}, number = {1}, year = {1928}, month = {1928}, pages = {107-108}, abstract = {In 1925, two clipping studies were established on the Jornada Range Reserve; one of tobosa grass (Hilaria mutica (Buckl.) Benth.) and one of black grama grass (Bouteloua eriopoda Torr.). The tobosa clipping study was composed of nine 1-meter quadrats, eight of which were used for clipping and the ninth used as a density control. The eight clipped quadrats were organized into four groups of two, each pair having one plot clipped at 2 inches and one clipped at 4 inches above ground. To obtain data representing varying intensities of grazing, each pair was clipped at a different time from the other three, the intervals being 1 week, 2 weeks, 4 weeks and at the end of the growing season. The quadrats cut at intervals of 1 and 2 weeks produced only short flower stalks between clippings. After the forage was air dried, it was weighed and the production of each quadrat was compared with the others on the basis of grams of dry forage per square decimeter of tuft area. The black grama clipping study was very similar to the tobosa study, except that the heights of clipping were 1 and 2 inches, while the clipping intervals were 2 weeks, 4 weeks, 6 weeks and at the end of the growing season. In starting the studies, the question arose of a proper and convenient method of clipping and saving the desired vegetation. At first, a pair of small sheep shears were used for cutting the grasses and later, a pair of paper shears were used, the clipped flower stalks being lifted with the free hand and deposited in a paper bag. This method required constant measurement to insure the proper height of grass left on the ground. Moreover, a considerable number of short flower stalks and leaves were lost by being flipped away when cut or lost through the operator{\textquoteright}s inability to hold with one hand all of the clipped vegetation. During the 1927 field season, an improved pair of shears was developed. This instrument, made from an ordinary pair of 10-inch paper shears, removes two of the outstanding faults found in the old method. The loss of leaves and short flower stalk tips is avoided by the presence of 1-inch high copper strips soldered onto the outer edges of the blades. Another distinct advantage of this tool is the adjustable gauge set on the side of one blade that eliminates the necessity of continually measuring the grass. Additionally, the gauge is attached {\textthreequarters} inch from the blade point. It appears that flower stalks in the midst of large tufts can be cut more easily if the gauge is set near the fulcrum of the shears. The gauge, which is graduated in half-inch intervals, is set at the desired height and the clipping is begun. The gauge is also equipped with a foot that prevents the shears from sinking into the ground and may be slipped from its slot and clamped parallel to the blades for convenient carrying. This instrument has reduced by a third the time it takes for clipping grasses on the Jornada and produces more accurate results.}, keywords = {black grama, clipping studies, improved, quadrats, shears, tobosa grass}, url = {/files/bibliography/013.pdf}, author = {R.S. Campbell and Canfield, R.H.} } @article {52644, title = {Increase cattle production on southwestern ranges}, year = {1917}, note = {//??//NONE//}, month = {1917}, keywords = {book, books, cattle,productivity, chapter, chapters, production,cattle, report, reports}, isbn = {U.S. Department of Agriculture Bulletin 588}, author = {Jardine, J. T. and Hurtt, L. C.} } @article {52643, title = {Increased cattle production on Southwestern ranges}, year = {1917}, month = {November 15, 191}, pages = {32 }, abstract = {This bulletin presents the results of experiments which bear directly on the problem of how to produce more and better cattle on western range lands, a matter of pressing importance in view of the present need for increasing the Nation{\textquoteright}s food supply.}, keywords = {cattle production, government publication, increased production, Southwestern ranges}, url = {/files/bibliography/005.pdf}, author = {Jardine, J. T. and Hurtt, L. C.} }