@article {JRN55427, title = {Adapting to climate change on desert rangelands: A multi-site comparison of grazing behavior plasticity of heritage and improved beef cattle}, journal = {Journal of Arid Environments}, volume = {209}, year = {2022}, month = {11/02/2022}, pages = {104886}, abstract = {Climate change is amplifying the spatiotemporal heterogeneity of desert rangeland forages through its impact on precipitation variability. Foraging behavior plasticity (an animal{\textquoteright}s ability to alter its behavior to cope with environmental variation) could be a key trait for climate adaptation of beef cattle in arid environments. We analyzed GPS-derived movement and activity data of Criollo and commercial beef cattle from eight studies conducted at sites in North and South America to determine whether seasonal and year-to-year behavior plasticity varied significantly between breeds. We calculated dormant/brown season or driest year percent change in foraging behavior relative to growing/green season or wettest year. Compared to commercial beef breeds, Criollo cattle exhibited significantly greater seasonal adjustment in daily distance traveled (20\% increase vs. 2\% decrease, P <= 0.02) and daily grazing effort (25\% vs. 1.5\% increase, P = 0.01) during the dormant/brown vs. growing/green season. Increase in daily area explored during the dormant/brown season was almost three times greater in Criollo vs. commercial beef cattle (P = 0.09). Seasonal adjustment in daily time spent grazing was similar for Criollo and commercial beef breeds. Increase in daily area explored during the dormant/brown season of dry vs. wet years was three times greater for Criollo vs. commercial beef breeds (P = 0.03). Criollo cattle tended (P = 0.09) to exhibit greater behavior adjustment than commercial beef counterparts in daily distance traveled during the dormant/brown season of dry vs. wet years (22\% vs. 4\% increase, respectively). No breed differences in adjustment of time spent grazing (P = 0.36) or grazing effort (P = 0.20) during dormant/brown season of dry vs. wet years were observed. Dry vs. wet year grazing behavior adjustments during the growing/green season were similar for both breeds. Grazing behavior plasticity observed in Criollo cows could be a critical trait for desert beef herds in the face of increasingly variable rainfall patterns occurring as a result of climate change.}, keywords = {Animal agriculture, British beef cattle, Cow-calf, criollo cattle, GPS tracking, ranching}, doi = {10.1016/j.jaridenv.2022.104886}, url = {files/bibliography/22-024.pdf}, author = {Andr{\'e}s F. Cibils and Richard E. Estell and S. Spiegal and Shelemia Nyamuryekung{\textquoteright}e and Matthew M. McIntosh and Danielle Duni and Oscar A. Herrera Conegliano and Felipe A. Rodr{\'\i}g Almeida and Octavio Roacho Estrada and Lisandro J. Blanco and Danielle Duni and S. A. Utsumi and Alfredo L. Gonzalez} } @article {JRN55378, title = {Adaptive monitoring for multiscale land management: Lessons learned from the Assessment, Inventory, and Monitoring (AIM) principles}, journal = {Rangelands}, volume = {44}, year = {2022}, month = {03/1/2022}, pages = {50-63}, abstract = {On the Ground {\textbullet} The BLM Assessment, Inventory, and Monitoring (AIM) strategy recommends five principles for building multiscale monitoring programs: standardized methods and indicators; data management and stewardship; appropriate sample designs; remote sensing integration; and structured implementation. These principles guide monitoring across public lands. {\textbullet} We find the AIM principles are sound and worthy of consideration for design and adaptation of rangeland monitoring programs worldwide. {\textbullet} An emergent principle, standard workflows and analysis frameworks for using data, connects data to land management decision-making and empowers land managers. {\textbullet} The AIM principles inspire and provide opportunities for the rangeland management community to implement adaptive management.}, keywords = {data management, decision-making, design, indicators, public lands, rangeland monitoring}, doi = {10.1016/j.rala.2021.08.006}, url = {files/bibliography/22-008.pdf}, author = {Emily Kachergis and Scott W. Miller and Melissa Dickard and Shannon Savage and Lindsay V. Reynolds and Nika Lepak and Chris Dietrich and Adam Green and Aleta Nafus and Karen Prentice and Zoe Davidson} } @article {JRN55409, title = {Accuracy of regional-to-global soil maps for on-farm decision making: Are soil maps {\textquotedblleft}good enough{\textquotedblright}?}, journal = {Egusphere}, year = {2022}, month = {5/19/2022}, abstract = {A major obstacle to selecting the most appropriate crops and closing the yield gap in many areas of the world is a lack of site-specific soil information. Accurate information on soil properties is critical for identifying soil limitations and the management practices needed to improve crop yields. However, acquiring accurate soil information is often difficult due to the high spatial and temporal variability of soil properties at fine scales and the cost and inaccessibility of laboratory-based soil analyses. With recent advancements in predictive soil mapping, there is a growing expectation that soil map predictions can provide much of the information needed to inform soil management. Yet, it is unclear how accurate current soil map predictions are at scales relevant to management. The main objective of this study was to address this issue by evaluating the site-specific accuracy of regional-to-global soil maps, using Ghana as a test case. Four web-based soil maps of Ghana were evaluated using a dataset of 6,514 soil profile descriptions collected on smallholder farms using the LandPKS mobile application. Results from this study revealed that publicly available soil maps in Ghana lack the needed accuracy (i.e., correct identification of soil limitations) to reliably inform soil management decisions at the 1{\textendash}2 ha scale common to smallholders. Standard measures of map accuracy for soil texture class and rock fragment class showed that all soil maps had similar performance in estimating the correct property class, with overall accuracies ranging from 8{\textendash}39 \% for soil texture classes and 26{\textendash}33 \% for soil rock fragment classes. Furthermore, there were substantial differences in soil property predictions among the four maps, highlighting that soil map errors are not uniform between maps despite their similar overall accuracies. To better understand the functional implications of these soil property differences, we used a modified version of the FAO Global Agro-Ecological Zone (GAEZ) soil suitability modelling framework to derive soil suitability ratings for each soil data source. Using a low-input, rain-fed, maize production scenario, we evaluated the functional accuracy of map-based soil property estimates. This analysis showed that soil map data significantly overestimated crop suitability for over 65 \% of study sites, potentially leading to ineffective agronomic investments by farmers, including cash-constrained smallholders.}, keywords = {accuracy, decision making, on-farm, regional-to-global, soil maps}, doi = {10.5194/egusphere-2022-246}, url = {files/bibliography/22-021.pdf}, author = {Jonathan Maynard and Edward Yeboah and Stephen Owusu and M. Buenemann and J. Neff and Jeffrey E. Herrick} } @article {JRN55374, title = {Adaptive monitoring in support of adaptive management in rangelands}, journal = {Rangelands}, volume = {44}, year = {2022}, month = {2/2022}, pages = {1-7}, abstract = {On the Ground {\textbullet} Monitoring supports iterative learning about the effectiveness of management actions, information that can help managers plan future actions, facilitate decision-making, and improve outcomes. {\textbullet} Adaptive monitoring is the evolution of a monitoring program in response to new management questions; new or changing environmental or socioeconomic conditions, improved monitoring methods, models, and tools; and experience implementing the monitoring program. {\textbullet} Adaptive monitoring is connected to research and management through the exchange of data; analytical, methodological, and technological developments; information; and understanding. {\textbullet} We review recent advances in adaptive monitoring and discuss new opportunities for both the research and management communities to improve monitoring in the years ahead.}, keywords = {adaptation, co-produ-ction, collaboration, innovation, partnership, rangeland science}, doi = {10.1016/j.rala.2021.07.003}, url = {files/bibliography/22-006.pdf}, author = {Sarah McCord and David Pilliod} } @proceedings {JRN55416, title = {Assessing grazing behavior of heritage, hybrid, and conventional cattle breeds in response to climate change}, year = {2022}, abstract = {Evidence suggests that heritage and hybrid beef cattle breeds exhibit more flexible foraging behaviors compared to highly selected conventional breeds. We hypothesize that these behaviors could be capitalized upon to support sustainability outcomes, such as biodiversity or climate change adaptation. We conducted a systematic search of studies that compared beef cattle breeds for behavioral traits and found 54 studies conducted since 1966 located in 9 of the 14 major terrestrial biomes, with 60 beef or dual-purpose breeds represented. We created a typology of the studies with respect to decade, continent, breed provenance (Continental, Criollo, Hybrid, B. indicus, Mediterranean, Sanga, British Isles), breed selection intensity (heritage [limited selection pressure], conventional [high selection pressure], hybrid [moderate selection pressure]), biome, study intent, and whether breeds met desired outcomes described by the study authors. Most studies (69\%) were conducted in arid rangeland settings in developed nations where researchers sought to minimize the negative environmental impacts of beef production. In comparisons of grazing behavior of heritage versus conventional types (n=25 studies), and hybrid versus conventional types (n=18 studies), heritage and hybrid cattle displayed more adapted traits (e.g., improved foraging distribution) in 88\% and 78\% of the studies, respectively. No differences were found in grazing behaviors in most studies in which heritage breeds were compared to other heritage breeds or conventional with conventional breeds (n=6 and 15 studies, respectively). In the subset of studies coded with the intent of {\textquotedblleft}foraging behavior,{\textquotedblright} heritage types traveled faster across a range of pasture sizes, which could indicate a capacity to seek high-quality nutrients while reducing trampling or overgrazing. Overall, our review suggests that breeds that have undergone moderate {\textendash} low selection pressure display grazing behaviors that demonstrate adaptation to their respective native environments and may help producers meet production goals in similar environments in the face of a changing climate.}, keywords = {behavior, cattle breeds, climate change, grazing, Heritage cattle, hybrid cattle}, author = {Matthew M. McIntosh and S. Spiegal and McIntosh, S. and Castano Sanchez, Jose and Richard E. Estell and Caitriana Steele and Emile H. Elias and C. Donovan Bailey and Joel R. Brown and Andr{\'e}s F. Cibils} } @article {JRN55278, title = {Assessing sustainability goals using big data: Collaborative adaptive management in the Malpai borderlands}, journal = {Rangeland Ecology \& Management}, volume = {77}, year = {2021}, month = {07/2021}, pages = {17-29}, chapter = {17}, abstract = {Collaborative adaptive management is a means to achieve social and ecological goals in complex natural resource management settings. Evaluation of collaborative management outcomes, however, is difficult at the scale of large landscapes. We developed an approach for such evaluations using long-term, spatiotemporal gridded or county-level datasets alongside local information on changes in ranch ownership. We applied this approach to evaluate the sustainability goals of the Malpai Borderlands Group (MBG) by comparing the MBG landscape to surrounding, similar desert grassland landscapes. We matched datasets, where possible, to management goals, including the preservation of ranching livelihoods, prevention of rangeland fragmentation by exurban development, sustaining the ecological role of fire, limiting or reversing woody plant encroachment into grasslands, sustaining rangeland productivity, and sustaining biodiversity. We found that the number of ranch families changed little since MBG was established, although several ranches were consolidated within some families or absentee owners, such that multiple families share other ranches. The number of beef cattle ranches declined within one MBG county, likely due to increasing depth to groundwater. Exurban development and rangeland-to-cropland conversion have been virtually nonexistent in the MBG landscape, while such conversions are common in adjacent landscapes. Coordinated fire planning with low fragmentation of rangeland has led to extensive fires in the MBG landscape, dwarfing the area burned in adjacent landscapes. The percent of land area exhibiting significant trends of increasing bare ground cover was intermediate in the MBG landscape compared with adjacent landscapes, while herbaceous and shrub cover exhibited significant trends in only a small fraction of the study region. Rangeland productivity exhibited significant declines in some landscapes, but declines were minimal in the MBG area. Our analysis suggests that collaborative adaptive management implemented by the MBG has aligned with their goals, but changing climate, water availability, and demography will become increasingly challenging.}, keywords = {big data, fire, plant production, ranch turnover, rangeland-cropland conversion, sustainability}, doi = {https://doi.org/10.1016/j.rama.2021.03.002}, url = {files/bibliography/21-012.pdf}, author = {Brandon T Bestelmeyer and S. Spiegal and Winkler, Rich and D. K. James and Matthew Levi and Jebediah C. Williamson} } @proceedings {JRN55298, title = {Adapt (or succumb) to climate change on rangelands}, year = {2021}, month = {2/11/2021}, pages = {1}, abstract = {Climate change puts the livelihoods of rangeland users worldwide at risk. Rangelands sequester and store greenhouse gases, as well as provide ground cover critical to moderation of temperature; rangelands also provide a majority of the forage consumed by domestic livestock globally. Despite the importance of rangelands to climate regulation and to the food production system, rangelands continue to be degraded or converted to other forms of agriculture. The interacting feedbacks between degradation-conversion-climate interaction creates a {\textquotedblleft}wicked problem{\textquotedblright}. As rangeland scientists, managers, students, policy makers, and conservationists interested in providing leadership for the stewardship of rangelands based on sound ecological and management principles, it is our duty to address this challenge to ensure the long-term productivity and sustainability of rangeland ecosystems. For this plenary session we have invited four people who deal with climate change on a daily basis to present what they think are the critical needs in adapting. They will discuss their views on critical needs to respond to climate change and, more importantly, how to move those ideas into the mainstream of science, policy and land management. They will also respond to questions from the audience.}, author = {Joel R. Brown and Emile H. Elias and Emmott, Angus and Mahuer, Anna and Hailey Wilmer} } @article {JRN55289, title = {Addressing air quality, agriculture, and climate change across the Southwest and Southern Plains: A roadmap for research, extension, and policy}, journal = {Bulletin of the American Meteorological Society}, volume = {102}, year = {2021}, month = {07/20/ 2021}, pages = {1394{\textendash}1401 }, abstract = {In February 2021, the USDA Southwest Climate Hub hosted the virtual event called the Southwest and Southern Plains Air Quality and Production Agriculture Science and Applications Workshop. The workshop follows the culmination of a nationwide effort assessing the current state of knowledge of air quality impacts on agricultural production, and vice versa. This benchmark effort necessitates further discussion, addressing remaining knowledge gaps and progress barriers with the expectation of a changing climate. The goal of the workshop was to identify these needs for the Southwest and southern Plains region and develop a roadmap of next steps intended for those in policy, research, and land management. Bringing focus to the Southwest and southern Plains summons local characteristics and capacities into perspective for impactful strategy development. Mid-century projections of intensifying droughts, seasonality shifts, and extreme weather events threaten to challenge the Southwest and southern Plains region. These climatic variations create new, and exacerbate current, air quality issues with implications for public well-being, agricultural production, and environmental health. Given the constancy of climate change projected for this region, greater attention must be given to the air quality{\textendash}agriculture relationship with climate change inherent to these explorations. The workshop convened professionals from health, agricultural, and environmental sectors, joining from 11 states and three countries (Canada, India, and the United States). Short presentations detailed the national assessment results, current mitigation options and resources available for the agricultural sector, current USDA Natural Resources Conservation Service (NRCS) air quality priorities, evolving indicators and models for emissions, and current measurement networks. Engagement activities throughout the workshop and a discussion session welcomed a flow of learning across all involved in the workshop, outlining a regional cross section of needs and priorities to be explored further.}, keywords = {Climate change; Agriculture; Air quality; Decision making; Policy; Societal impacts}, doi = {10.1175/BAMS-D-21-0088.1}, url = {files/bibliography/21-025.pdf}, author = {Maude Dinan and Emile H. Elias and Nicholas Webb and G. Zwicke and Timothy S. Dye and Skye Aney and Michael Brady and Joel R. Brown and Robert R. Dobos and David Dubois and Brandon Edwards and Sierra Heimel and Nicholas Luke and Caitlin M. Rottler and Caitriana Steele} } @article {JRN55307, title = {AI recommender system with ML for agricultural research}, journal = {IEEE IT Professional}, volume = {22}, year = {2020}, month = {05/01/2020}, pages = {29-32}, abstract = {We describe an AI recommender system (RS) with machine learning to harness past user choices and large volumes of data, yet account for changes in weather and management decisions characteristic of agricultural systems. Our goal is to maximize the use of data relevant to solving agricultural problems and improve the efficiency of the scientific workforce while also improving the accuracy of estimates of the amount of food produced. Our example shows how the RS learns data analysis choices from user behavior for predicting agricultural production responses to rainfall and learns to identify classes of agroecosystem responses to alternative climate scenarios. We account for changes in relationships using spatial and temporal statistics. The RS provides a powerful approach to make use of the large amounts of data and scientific expertise in the agricultural enterprise to predict agroecosystem dynamics under changing environmental conditions.}, doi = {10.1109/MITP.2020.2986125}, url = {files/bibliography/20-037.pdf}, author = {Debra C. Peters and Heather Savoy and Geovany Ramirez and C. Huang} } @article {JRN55149, title = {Applicability of functional groups as indicators of resilience and redundancy in the San Pedro Watershed, Arizona}, journal = {AIMS Environmental Science}, volume = {6}, year = {2019}, month = {05/2019}, pages = {127-146}, chapter = {127}, abstract = {

Resilience and redundancy are important for long-term conservation since both can indicate the condition and integrity of ecosystems. The goal of this research was to define, develop and demonstrate methods to measure resilience and redundancy in a spatially explicit manner in the San Pedro Watershed, Arizona. Species were categorized to one of several functional groups based on body mass and diet. We calculated metrics of resilience and redundancy for each functional group. Functional groups with smaller-bodied animals had more species than groups with larger-bodied animals suggesting increased resiliency and redundancy for those small-bodied groups. Small-bodied groups were the only body mass groups to include species representing all diet categories (i.e., carnivores, herbivores, omnivores, insectivores, granivores, nectarivores, and piscivores). The insectivore functional group was highly redundant; 154 of 283 (54\%) bird species and 23 of 85 (27\%) mammal species were insectivores. Carnivorous bird species (37 of 283; 13\%) and omnivorous mammal species (23 of 85; 27\%) also showed high redundancy relative to other dietary functional groups. Spatial analysis identified the northern portion of the watershed with low mean redundancy for most functional groups across both birds and mammals. Results highlight the importance of large carnivores and small mammals within ecosystems. Results also highlight current ecosystem services provided by insectivorous and nectarivorous species in the American Southwest. This process can be used to measure resilience and redundancy in a spatially explicit manner providing managers information for conservation in the face of climate change when using limited dollars to plan for future changes.

}, keywords = {conservation, functional groups, redundancy, resilience, San Pedro Watershed, vertebrates}, doi = {10.3934/environsci.2019.3.127}, url = {files/bibliography/19-021.pdf}, author = {Leimer, Allison K. and Ken Boykin and C.A. Anderson and Caitriana Steele} } @conference {JRN55058, title = {Area estimates of wind friction velocity derived from net radiometers and MODIS albedo}, booktitle = {American Meteorological Society}, year = {2019}, month = {01/2019}, publisher = {American Meteorological Society}, organization = {American Meteorological Society}, address = {Phoenix, AZ}, abstract = {

Soil surface properties influence the resistance of soils to wind erosion through their effects on the aerodynamic roughness of the surface (z0), the threshold friction velocity for particle entrainment (u*t), and the supply of loose erodible material. The spectral reflectance of the soil surface, and its albedo, are influenced by the same soil properties. A relation between the surface albedo and its aerodynamic roughness has been established, enabling estimates of wind erosion to be obtained from available satellite data. Here we compare estimates of wind friction velocity derived from traditional methods (wind velocity profiles) with those derived from the albedo model, at two separate scales {\textendash} bare soil patch (via net radiometers) and landscape (via MODIS 500m albedo datasets). Results suggest that estimates of u* from wind velocity profiles are highly variable and therefore uncertain as they changes in response to wind speed, direction, turbulence scales, and heterogeneity of the surface roughness. Albedo-derived estimates of surface wind friction velocity at both scales have smaller uncertainty as they are integrative over the measurement area, in addition to resolving the partition of wind momentum between roughness elements and the soil surface. With albedo-derived area estimates of wind friction velocity at the soil surface, the accuracy of aeolian sediment transport estimates across scales is improved.

}, author = {Parker, Nancy and Nicholas Webb and A. Chappell and Susan LeGrand} } @conference {JRN54944, title = {AERO, a wind erosion modeling framework with applications to monitoring data}, booktitle = {73rd Soil and Water Conservation Society International Annual Conference }, year = {2018}, month = {07/2018}, address = {Albuquerque, New Mexico}, abstract = {

The Aeolian Erosion Model (AERO) is a flexible aeolian transport and dust emission modeling framework developed to inform fundamental research and provide decision support for land managers. The model simulates size-resolved horizontal and vertical mass flux on the plot scale from user inputs of meteorological, soil and vegetation data via user-selectable drag portioning, transport and emission schemes. AERO is adaptable to many research and management applications over a range of site conditions and can leverage emerging large-scale ecological datasets to provide new opportunities to evaluate aeolian sediment transport responses to land surface conditions, potential interactions with disturbances and ecological change, and impacts of anthropogenic land use and land cover change.

}, author = {Brandon Edwards and Nicholas Webb and Sarah McCord} } @conference {JRN54943, title = {AERO: An Aeolian erosion modeling environment}, booktitle = {International Conference on Aeolian Research}, year = {2018}, month = {06/2018}, address = {Bordeaux, France}, abstract = {

The Aeolian Erosion Model (AERO) is a versatile aeolian transport and dust emission modeling environment developed to provide a robust interface for fundamental research while also acting as a decision-support tool for land managers. The model simulates size-resolved horizontal and vertical mass flux on the plot scale from user inputs of meteorological, soil and vegetation data. AERO is highly customizable; the model can be run for a single set of conditions, a time series of conditions, conditions over space, or a time series of conditions over space. Drag partitioning, vertical dust emission schemes, and horizontal transport equations are user-selectable. Key variables (e.g., vegetation cover, canopy gap distribution, soil type) can be input as scalars, defined by descriptive statistics, supplied as probability distributions, or, when run spatially, as remote sensing-derived inputs and atmospheric data from the Weather Research and Forecasting (WRF) weather prediction model. As such, the model is adaptable to many research and management applications over a range of site conditions. Here, we detail the model framework and processing options and provide an example of model application to U.S. Bureau of Land Management (BLM) Assessment, Inventory and Monitoring (AIM) plots in New Mexico, USA to assess potential implications of management actions for dust emission rates. The test case demonstrates how the AERO model can leverage emerging large-scale ecological datasets like AIM to provide new opportunities to evaluate aeolian sediment transport responses to land surface conditions, potential interactions with disturbances and ecological change, and impacts of anthropogenic land use and land cover change.

}, author = {Brandon Edwards and Sarah McCord and Nicholas Webb and Nelson Stauffer} } @article {JRN54947, title = {Advancing the Sustainability of US Agriculture through Long-Term Research}, journal = {Journal of Environmental Quality}, volume = {47}, year = {2018}, month = {11/2018}, pages = {1412-1425}, chapter = {1412}, abstract = {

Agriculture in the United States must respond to escalating\ demands for productivity and efficiency, as well as pressures to
improve its stewardship of natural resources. Growing global\ population and changing diets, combined with a greater societal
awareness of agriculture{\textquoteright}s role in delivering ecosystem services\ beyond food, feed, fiber, and energy production, require a
comprehensive perspective on where and how US agriculture\ can be sustainably intensified, that is, made more productive
without exacerbating local and off-site environmental concerns.\ The USDA{\textquoteright}s Long-Term Agroecosystem Research (LTAR) network
is composed of 18 locations distributed across the contiguous\ United States working together to integrate national and local
agricultural priorities and advance the sustainable intensification\ of US agriculture. We explore here the concept of sustainable
intensification as a framework for defining strategies to enhance\ production, environmental, and rural prosperity outcomes from\ agricultural systems. We also elucidate the diversity of factors\ that have shaped the past and present conditions of cropland,\ rangeland, and pastureland agroecosystems represented by the\ LTAR network and identify priorities for research in the areas of\ production, resource conservation and environmental quality,\ and rural prosperity. Ultimately, integrated long-term research\ on sustainable intensification at the national scale is critical to\ developing practices and programs that can anticipate and\ address challenges before they become crises.

}, doi = {doi:10.2134/jeq2018.05.0171}, url = {files/bibliography/18-020.pdf}, author = {Peter J. A. Kleinman and S. Spiegal and James Rigby JR and Sarah Goslee and J. M. Baker and Brandon T Bestelmeyer and Raoul K. Boughton and Ray Bryant and Michael Cavigelli and J. D. Derner and Emily Duncan and David C. Goodrich and David Huggins and K.W. King and M. A. Liebig and Martin Locke and Steven Mirsky and G. E. Moglen and Thomas Moorman and Frederick B. Pierson and Robertson, G. P. and John Sadler and Shortle, J. S. and Jean Steiner and Timothy Strickland and Hilary Swain and T. Tsegaye and M. R. Williams and C. Walthall} } @article {JRN54892, title = {Applying Ecological Site Concepts and State-and-Transition Models to a Grazed Riparian Rangeland}, journal = {Ecology and Evolution}, year = {2018}, month = {04/2018}, abstract = {

Ecological site and state-and-transition models are useful tools for generating and testing hypotheses about drivers of vegetation composition in non-equilibrium systems, and have been widely implemented on rangelands. Compared to upland areas, little attention has been given to developing ecological site concepts for rangeland riparian areas, and additional environmental criteria may be necessary to classify riparian ecological sites. Between 2013 and 2016, fifteen study reaches on five creeks were studied at Tejon Ranch in southern California. Data were collected to describe the relationship between riparian vegetation composition and environmental variables, and to explore the utility of ecological site and state-and-transition models for describing vegetation communities and for creating hypotheses about drivers of vegetation change. Hierarchical cluster analysis was used to classify the environmental and vegetation data (15 stream reaches * 4 years) into two ecological sites and eight community phases that comprised three vegetation states. Classification and regression tree (CART) analysis was used to determine the influence of abiotic site variables on vegetation clusters. Channel slope explained the greatest amount of variation in vegetation clusters; however, soil texture, geology, watershed size, and elevation were also selected as important predictors of vegetation composition. The classification tree built with this limited set of abiotic predictor variables explained 90\% of the observed vegetation clusters. Abiotic variables explained almost all of the observed riparian vegetation dynamics, suggesting that non-equilibrium models would be well-suited for understanding and predicting change in this highly variable system. Indeed, ecological site and state-and-transition models provided a robust framework for describing riparian vegetation states and generating testable hypotheses about vegetation dynamics and their relationship to environmental and management variables. These findings support continued development of riparian ecological site concepts and state-and-transition models to aid decision making for conservation and management of rangeland riparian areas.\ 

}, keywords = {CART analysis, ecological site descriptions, grazing management, hierarchical cluster analysis, riparian classification}, doi = {10.1002/ece3.4057}, url = {/files/bibliography/18-007.pdf}, author = {Ratcliff, Felix and James Bartolome and Macaulay, Luke and S. Spiegal} } @article {JRN54882, title = {Among-species overlap in rodent body size distributions predicts species richness along a temperature gradient}, journal = {Ecography}, volume = {41}, year = {2018}, pages = {1-10}, abstract = {

Temperature is widely regarded as a major driver of species richness, but the mechanisms are debated. Niche theory suggests temperature may affect richness by filtering traits and species in colder habitats while promoting specialization in warmer ones. However, tests of this theory are rare because niche dimensions are challenging to quantify along broad thermal gradients. Here, we use individuallevel trait data from a long-term monitoring network spanning a large geographic extent to test niche-based theory of community assembly in small mammals. We examined variation in body size among 23 communities of North American rodents sampled across the National Ecological Observatory Network (NEON), ranging from northern hardwood forests to subtropical deserts. We quantified body size similarity among species using a metric of overlap that accounts for individual variation, and fit a structural equation model to disentangle the relationships between temperature, productivity, body size overlap, and species richness. We document a latitudinal gradient of declining similarity in body size among species towards the tropics and overall increase in the dimensions of community-wide trait space in warmer habitats. Neither environmental temperature nor net primary productivity directly affect rodent species richness. Instead, temperature determines the community-wide niche space that species can occupy, which in turn alters richness. We suggest a latitudinal gradient of trait space expansion towards the tropics may be widespread and underlie gradients in species diversity.

}, keywords = {NEON, rodent metrics, rodents, small mammals, species richness}, doi = {10.1111/ecog.03641}, url = {files/bibliography/JRN54882.pdf}, author = {Read, Quentin D. and Grady, John M. and Zarnetske, Phoebe L. and Record, Sydne and Baiser, Benjamin and Belmaker, Jonathan and Tuanmu, Mao-Ning and Strecker, Angela and Beaudrot, Lydia and Thibault, Katherine M.} } @conference {JRN54912, title = {Agricultural Production Risk in a Changing Climate: Assessing Causes of Loss Using Crop Insurance Data}, 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 = {

The synthesis and analysis of existing {\textquoteleft}big data{\textquoteright} in the agricultural sector can yield additional insights of such knowledge in a changing climate, as well as increase the collective value of these data. The creation of the U.S. Department of Agriculture (USDA) Climate Hub network prioritizes this with information synthesis and tool development as tangible outputs. 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 ultimate stakeholders - farmers, ranchers, and land managers. The USDA Risk Management Agency (RMA) is responsible for overseeing the Federal crop insurance program and works with private insurance companies. 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).

Results/Conclusions:We first describe an initial retrospective analysis of causes of loss at multiple spatial and temporal scales over the United States. We find that drought and excess moisture are the top two causes of loss since 2001, and are responsible for over 70\% of nationwide climate-related crop loss payments. Regional differences in top causes of loss demonstrate the complex interactions of biophysical, climatic, socio-economic, and geo-political factors. Causes of loss over time show distinct trends as a function of major weather disasters and long-term climate events, such as drought. Using this information, we engage our partners and stakeholders to develop decision-relevant products related to crop insurance and create opportunities for future research co-production. A web-based tool is also developed to deliver these crop insurance data to our partners and stakeholders for increased accessibility, discoverability, and usability. Ultimately, we envision the project supporting targeted adaptation in high production risk areas, multi-scale land management decisions, and ecosystem resilience.

}, author = {J.T. Reyes and Andrew Eischens and Shilts, Mark and Jebediah C. Williamson and Emile H. Elias} } @conference {JRN54789, title = {Apathy, ignorance, and poor governance: the three-headed Hydra of drylands}, booktitle = {Ecological Society of America Annual Meeting}, year = {2017}, month = {08/2017}, publisher = {Ecological Society of America Annual Meeting}, organization = {Ecological Society of America Annual Meeting}, address = {Portland, OR}, abstract = {

Proximate threats to drylands include drivers such as overharvesting or land conversion. I argue that these proximate threats are ultimately related to popular and scientific perceptions of drylands and, consequently, how investments translate into governance. First, what is degradation in drylands? Scientists debate this topic and the public often doesn{\textquoteright}t care. Second, if a dryland is judged to be degraded, what should we do about it? Ignorance of social and ecological processes can lead to actions (or inactions) that make things worse. To better manage drylands, we need to popularize their importance and improve models of how they function.

}, author = {Brandon T Bestelmeyer} } @proceedings {JRN54680, title = {Application of the BLM{\textquoteright}s assessment, inventory, and monitoring strategy for reclamation and restoration monitoring}, volume = {Jan 29 - Feb 02, 2017}, year = {2017}, month = {01/2017}, publisher = {Society for Range Management}, address = {Saint George, Utah}, abstract = {
Monitoring of reclamation or restoration activities ({\textquotedblleft}restoration monitoring{\textquotedblright} for brevity) is a crucial step in adaptive management not only to judge effectiveness of a restoration action but also to build evidence for its overall efficacy and context in which it is appropriate. Restoration monitoring should be targeted to detect the desired effects (and anticipated side effects) of the action. However, there is great value in adopting consistent monitoring indicators and methods to facilitate the use of existing data, leverage data quality and management processes already in place, and gain the ability to view restoration activities in the context of larger landscape monitoring efforts. The Bureau of Land Management{\textquoteright}s (BLM) Assessment, Inventory, and Monitoring (AIM) program provides a strategy for monitoring the status and trend of BLM rangelands at multiple scales, report on the effectiveness of monitoring actions, and provide information necessary for BLM to implement adaptive management. The AIM strategy emphasizes a set of core indicators and methods and statistically-based sampling design to provide consistency and rigor to BLM monitoring. AIM is a flexible tool that can be applied to situations like restoration monitoring (e.g., via use of supplemental indicators) while retaining compatibility with larger scale monitoring efforts. There are several ways in which the AIM strategy or existing AIM data can be applied to restoration monitoring including: augmenting existing restoration monitoring; using in before-after-control-impact (BACI) sampling designs; comparing data from restoration sites to either nearby similar AIM sites or to a collection of AIM sites from the same land type; or comparison of restoration monitoring data to reference conditions developed from a larger collection of AIM data. We will illustrate each of these approaches through examples of where BLM has used AIM data for restoration monitoring in northwestern Colorado, northern New Mexico, and eastern Alaska.
}, author = {Alexander Laurance-Traynor and Jason W. Karl and Zoe Davidson and J. Davis} } @article {JRN54666, title = {Abiotic processes are insufficient for fertile island development: A 10-year artificial shrub experiment in a desert grassland}, journal = {Geophysical Research Letters}, volume = {44}, year = {2017}, month = {03/2017}, pages = {2245-2253}, chapter = {2245}, abstract = {

The relative importance of biotic and abiotic processes in the development of {\textquotedblleft}fertile islands{\textquotedblright} in dryland systems has rarely been investigated. Here we approached this question by using artificial shrubs, which exclude plant litter production and soil nutrient uptake, but retain the functions of trapping windblown material, funneling of stemflow, and differential rain splash. We conducted a vegetation manipulation study more than a decade ago in the desert grassland of southern New Mexico and subsequently revisited the site in 2012 and 2015. The results show that no notable soil mounds were observed under the artificial shrubs; however, soil texture under the artificial shrubs has gradually changed to resemble the patterns of soil particle-size distribution under natural shrubs. Our results highlight that with the exclusion of direct biotic additions, soils captured by shrub canopies are not necessarily fertile and thus do not themselves contribute to the development of fertile islands.

}, keywords = {abiotic processes, aeolian process, artificial shrubs, biotic process, desert grassland, fertile islands}, doi = {10.1002/2016GL072068}, url = {/files/bibliography/17-005.pdf}, author = {Junran Li and William P. Gilhooly III and Gregory S. Okin and John Blackwell III} } @article {JRN55178, title = {Aligning Land Use with Land Potential: The Role of Integrated Agriculture}, journal = {AGRICULTURAL \& ENVIRONMENTAL LETTERS}, year = {2017}, month = {April 13, 2017}, chapter = {1-5}, abstract = {

Contemporary agricultural land use is dominated by an emphasis on provisioning services by applying energy-intensive inputs through relatively uniform production systems across variable landscapes. This approach to agricultural land use is not sustainable.\  Achieving sustainable use of agricultural land should instead focus on the application of innovative management systems that provide multiple ecosystem services on lands with varying inherent qualities. Integrated agricultural systems (IAS) represent an alternative approach to prevailing land use, whereby site adapted enterprises are implemented to enhance synergistic resource transfer among enterprises and sustainable delivery of ecosystem services. Sustainable deployment of IAS on agricultural land involves placing the {\textquotedblleft}right enterprise{\textquotedblright} at the {\textquotedblleft}right intensity{\textquotedblright} at the {\textquotedblleft}right time{\textquotedblright} on the {\textquotedblleft}right location,{\textquotedblright} with the inherent attributes of location providing guidance for management decisions. There is an urgent need to design IAS that enhance delivery of ecosystem services while ensuring land potential thresholds are not exceeded.

}, doi = {10.2134/ael2017.03.0007}, url = {files/bibliography/17-035.pdf}, author = {M. A. Liebig and Jeffrey E. Herrick and D W Archer and J.P. Dobrowolski and S. W. Duiker and A. J. Franzluebbers and John Hendrickson and R. Mitchell and A. Mohamed and J. W. Russell and Timothy Strickland} } @proceedings {JRN54679, title = {An automated approach to mapping ecological sites using hyper-temporal remote sensing and SVM classification}, volume = {Jan 01 - Feb 02, 2017}, year = {2017}, month = {01/2017}, publisher = {Society for Range Management}, address = {Saint George, Utah}, abstract = {

The development of ecological sites as management units has emerged as a highly effective land management framework, but its utility has been limited by spatial ambiguity of ecological site locations in the U.S., lack of ecological site concepts in many other parts of the world, and the inability to accurately assess the state of ecological sites or monitor changes in state through time. Here we present a modeling framework for high-resolution mapping of ecological sites in a semi-arid ecosystem using hyper-temporal remote sensing (i.e., hundreds of images) and support vector machine (SVM) classification. Results from this study show that SVM classification was effective in modeling ecological sites using a 28-year time series of normalized difference vegetation index (NDVI), with a 62\% correct classification. Results were compared to Soil Survey Geographic database and expert delineated maps of ecological sites which had a 51 and 89\% correct classification, respectively. The hyper-temporal remote sensing framework is effective in modeling the spatial distribution of ecological sites through its ability to characterize the soil-vegetation relationship and its response to climatic variability (i.e., drought or elevated rainfall). Additionally, the proposed hyper-temporal remote sensing technique may provide an objective framework to evaluate and test ecological site concepts through examining differences in vegetation dynamics in response to climatic variability, as well as the ability to assess and monitor changes in ecological state due to other change drivers. Given limited financial and human resources, an improved understanding of ecosystem potential is needed to maximize ecosystem services, promote the recovery of degraded lands, and adapt to and mitigate the impacts of climate change. The hyper-temporal remote sensing approach presented here has potential to greatly improve the efficiency of high-resolution ecological site mapping, and highlights its utility in terms of reduced cost and time investment relative to traditional manual mapping approaches.

}, author = {Jonathan Maynard and Jason W. Karl} } @proceedings {JRN54665, title = {Analytical approaches to quality assurance and quality control in rangeland monitoring data}, volume = {Jan 1 - Feb 2, 2017, Saint George, Utah}, year = {2017}, month = {01/2017}, publisher = {Society for Range Management}, address = {Saint George, Utah}, abstract = {
Producing quality data to support land management decisions is the goal of every rangeland monitoring program. However, the results of quality assurance (QA) and quality control (QC) efforts to improve data quality are rarely reported. The purpose of QA and QC is to prevent and describe non-sampling errors that introduce noise into monitoring datasets, thereby increasing the repeatability, defensibility, and usability of the data collected. Quality assurance is a proactive process designed to prevent errors from occurring, while QC is a reactive process whereby the number, nature, and implications of errors are identified. Common QA practices include careful design and documentation of the monitoring programs and protocols; training and calibration of data collectors; and structured management of resulting data. Quality control describes errors via data checks for incomplete or invalid values, variance decomposition, and evaluation of signal-to-noise ratios. We analyzed the calibration results and field data of two national monitoring datasets collected between 2011 and 2016. Field and lab calibration data demonstrate that the iterative learning by data collectors which occurs in QA improves field sampling results and can point to areas of future training. We also explored quantitative QC approaches for identifying and visualizing erroneous observations by comparing results to other data sources; and analyzing between-observer variability, patterns of missing data, and seasonal trends in method implementation - all of which help to describe the errors in these national datasets. We conclude that the results of the QA and QC processes can and should be evaluated to improve and document the quality of monitoring data. These evaluations can be used to improve monitoring data collection efforts and to support the role of rangeland monitoring in decision making.\ 
}, author = {Sarah McCord and Jason W. Karl and Justin Van Zee and Ericha Courtright} } @conference {JRN54920, title = {Assessing Climate Risk on Agricultural Production: Insights Using Retrospective Analysis of Crop Insurance and Climatic Trends}, booktitle = {American Geophysical Union}, year = {2017}, month = {12/2017}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {New Orleans, LA}, abstract = {

The collaborative synthesis of existing datasets, such as long-term climate observations and farmers{\textquoteright} crop insurance payments, can increase their overall collective value and societal application. The U.S. Department of Agriculture (USDA) Climate Hubs were created 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 mission, Hubs work across USDA and other climate service agencies to synthesize existing information. The USDA Risk Management Agency (RMA) is responsible for overseeing the Federal crop insurance program which currently insures over $100 billion in crops annually. RMA hosts data describing the cause for loss (e.g. drought, wind, irrigation failure) and indemnity amount (i.e. total cost of loss) at multiple spatio-temporal scales (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 assess climate risk on agricultural production and provide regionally-relevant information to stakeholders to promote resilient working landscapes. We performed a retrospective trend analysis at the state-level for the American Southwest (SW). First, we assessed indemnity-only trends by cause of loss and crop type at varying temporal scales. Historical monthly weather data (i.e. precipitation and temperature) and long-term drought indices (e.g. Palmer Drought Severity Index) were then linked with indemnities and grouped by different causes of loss. Climatological ranks were used to integrate historical comparative intensity of acute and long-term climatic events. Heat and drought as causes of loss were most correlated with temperature and drought indicators, respectively. Across all SW states increasing indemnities were correlated with warmer conditions. Multiple statistical trend analyses suggest a framework is necessary to appropriately measure the biophysical signals in crop insurance trends taking into account spatio-temporal characteristics. Based on stakeholder feedback, we also developed a web-based information browser to visualize and assess indemnity trends providing useful and usable knowledge to support informed land management decisions and ecosystem resilience.

}, author = {J.T. Reyes and Andrew Eischens and Shilts, Mark and Jebediah C. Williamson and Emile H. Elias} } @conference {JRN54811, title = {Assessing quality of citizen scientists{\textquoteright} soil texture estimates to evaluate land potential}, booktitle = {Soil Science Society of America Journal}, year = {2017}, month = {10/2017}, publisher = {Soil Science Society of America}, organization = {Soil Science Society of America}, address = {Tampa, FL}, abstract = {

Texture influences nearly all soil processes and is often the most measured parameter in soil science. Estimating soil texture is a universal and fundamental practice applied by resource scientists to classify and understand the behavior and management of soil systems. While trained soil scientist can accurately estimate soil textural class, percent sand, and percent clay, doubt is often cast on the quality of texture estimates produced by inexperienced citizen scientists. We present analysis of citizen scientist texture-by-feel and laboratory hydrometer derived soil texture classes collected from Namibia, Africa. Participants received minimal training and were provided with the Land Potential Knowledge System (LandPKS) app LandInfo module containing soil texture-by-feel walkthrough instructions. LandPKS is a free and open source mobile and web app that facilitates the collection and recording of georeferenced data on soil properties and site characteristics. Analysis of texture accuracy was compared using confusion matrix analysis to evaluate user and classification accuracy. Classification of sandy and clayey textural classes were most accurate while loamy soil texture classes were poorly predicted. Results showed poor total classifier accuracy (38\%), although classification improved significantly (59\%) when sand and sandy loam categories where combined as misclassification between the sandy texture classes was generally due to soil material containing higher organic matter content. Most incorrect identifications were not considered a serious problem because estimates fell within adjacent textural classes. When combined with LandPKS geotagged smart phone location, our analysis suggests that surface and subsurface texture class estimates were sufficient to match key soil components from the FAO Harmonized World Soil Database and the ISRIC SoilGrids global databases

}, author = {S. W. Salley and Jeffrey E. Herrick} } @proceedings {JRN54683, title = {Applying ecological site concepts to adaptive conservation management on an iconic Californian landscape}, year = {2017}, month = {01/2017}, publisher = {2017 Society for Range Management Meeting}, address = {St. George, Utah}, abstract = {
Tejon Ranch is a spectacular landscape valued for its biological diversity, livestock production, and cultural heritage. Situated at the convergence of three of California{\textquoteright}s major biogeographic zones, it is the largest, contiguous private property in the state. Since 2008, the ranch has operated under a conservation agreement tailored toward conservation and economic outcomes. We developed an ecological site group model to inform adaptive conservation-focused grazing on 40,000 ha of grasslands on the ranch. Each ecological site group (ESG) is based on a {\textquotedblleft}geologic landform{\textquotedblright} class: \ a unique combination of biogeographic region, geologic material and age, dominant formative geomorphology, elevation, and slope that supports a distinct set of soils and vegetation dynamics. We randomly established 57 permanent plots within the geologic landform classes. Sampling these plots over several years allowed us to evaluate the spatial and temporal variation within and among geologic landform classes and to build data-driven, quantitative ESGs and state-and-transition models (STMs). Using these models, we developed hypotheses about suitable management practices for conservation goals. We discuss in detail the Holocene Flats ESG, which we identified as having the highest potential for the enhancement of conservation values through altered grazing practices predicted to favor several taxa, including the San Joaquin kit fox, blunt-nosed leopard lizard, and native annual forbs. The predicted responses are currently being tested and monitored, but the ESG/STM conceptual framework has already helped conservation land managers and graziers to better understand how the variation in the Tejon landscape affects the distribution of conservation targets and the specific locations where management can be tailored to enhance biodiversity.
}, author = {S. Spiegal and James Bartolome and White, Michael} } @article {JRN54802, title = {Asynchrony among local communities stabilises ecosystem function of metacommunities}, journal = {Ecology Letters}, year = {2017}, abstract = {

Temporal stability of ecosystem functioning increases the predictability and reliability of ecosystem services, and understanding the drivers of stability across spatial scales is important for land management and policy decisions. We used species-level abundance data from 62 plant communities across five continents to assess mechanisms of temporal stability across spatial scales. We assessed how asynchrony (i.e. different units responding dissimilarly through time) of species and local communities stabilised metacommunity ecosystem function. Asynchrony of species increased stability of local communities, and asynchrony among local communities enhanced metacommunity stability by a wide range of magnitudes (1{\textendash}315\%); this range was positively correlated with the size of the metacommunity. Additionally, asynchronous responses among local communities were linked with species{\textquoteright} populations fluctuating asynchronously across space, perhaps stemming from physical and/or competitive differences among local communities. Accordingly, we suggest spatial heterogeneity should be a major focus for maintaining the stability of ecosystem services at larger spatial scales.

}, keywords = {alpha diversity, alpha variability, beta diversity, biodiversity, CoRRE data base, patchiness, plant communities, primary productivity, species synchrony}, doi = {10.1111/ele.12861}, url = {files/bibliography/JRN00655.pdf}, author = {Wilcox, Kevin R. and Tredennick, Andrew T. and Koerner, Sally E. and Grman, Emily and Hallett, Lauren M. and Avolio, Meghan L. and La Pierre, Kimberly J. and Houseman, Gregory R. and Isbell, Forest and David Samuel Johnson and Alatalo, Juha M. and Baldwin, Andrew H. and Bork, Edward W. and Elizabeth H. Boughton and Bowman, William D. and Britton, Andrea J. and James F. Cahill Jr. and S.L. Collins and Du, Guozhen and Eskelinen, Anu and Gough, Laura and Jentsch, Anke and Kern, Christel and Klanderud, Kari and A. K. Knapp and Kreyling, Juergen and Luo, Yiqi and McLaren, Jennie R. and Megonigal, Patrick and Onipchenko, Vladimir and Prev{\'e}y, Janet and Price, Jodi N. and Robinson, Clare H. and O. E. Sala and M. D. Smith and Soudzilovskaia, Nadejda A. and Souza, Lara and D. Tilman and White, Shannon R. and Xu, Zhuwen and Laura Yahdjian and Yu, Qiang and Zhang, Pengfei and Yunhai Zhang} } @article {JRN54608, title = {Applying ecological site concepts to adaptive conservation management on an iconic Californian landscape}, journal = {Rangelands}, volume = {38}, year = {2016}, month = {12/2016}, chapter = {365}, abstract = {
Tejon Ranch is a spectacular landscape valued for its biological diversity, livestock production, and cultural heritage. Situated at the convergence of three of California{\textquoteright}s major biogeographic zones, it is the largest, contiguous private property in the state. Since 2008, the ranch has operated under a conservation agreement that established adaptive livestock management for conservation and economic outcomes. We developed and applied ecological site concepts to adaptive conservation-focused grazing on 40,000 ha of grasslands on the ranch. Environmental heterogeneity, non-equilibrium system controls, and unpredictable rainfall required novel ecological site descriptions (ESDs) and state-and-transition models (STMs) to understand system history and dynamics, and to predict responses to management. Each ecological site is based on a {\textquotedblleft}geologic landform{\textquotedblright} class: \ a unique combination of biogeographic region, geologic material and age, dominant formative geomorphology, elevation, and slope that supports a distinct set of soils and vegetation dynamics. We randomly established 57 permanent plots within geologic landform classes. Sampling these plots over several years allowed us to evaluate the spatial and temporal variation within and among geologic landform classes and to build data-driven, quantitative ESDs and STMs. Using these models, we developed hypotheses about suitable management practices for conservation goals. We discuss in detail the Holocene Flats ESD, which we identified as having the highest potential for enhancement of conservation values through altered grazing practices predicted to favor several taxa, including the San Joaquin kit fox, blunt-nosed leopard lizard, and native annual forbs. The predicted responses are currently being tested and monitored.
}, doi = {10.1016/j.rala.2016.10.002}, url = {files/bibliography/16-029.pdf}, author = {S. Spiegal and James Bartolome and White, Michael} } @conference {JRN54640, title = {Assessing Crop Vulnerability to Climate Change: A Southwest Perspective}, booktitle = {Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting}, year = {2016}, month = {11/2016}, publisher = {Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting}, organization = {Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting}, address = {Phoenix, AZ}, abstract = {
The USDA Southwest Regional Climate Hub is one of ten Climate Hubs and Sub-hubs established in 2014. The Hub region includes Arizona, California (partnering with the California Sub-Hub), Nevada, New Mexico and Utah. \ Beyond the mainland States, the SW hub also serves Hawaii and the US affiliated Pacific Islands. The Hub{\textquoteright}s primary mission is to deliver science-based knowledge and practical information to farmers, ranchers and forest landowners to help them adapt to changing environmental conditions. One of the recent activities of the hub was to review climate change impacts on Southwestern agriculture, with a specific focus on vulnerability. In considering vulnerability, we reviewed factors relating to (i) exposure of systems to the impacts of climate change, (ii) the inherent ability of systems to withstand exposure to the changing climate and (iii) adaptive capacity. In this presentation, we highlight some of the key findings from our review of regional vulnerabilities and we discuss a potential framework for vulnerability assessment of southwestern cropping systems. If vulnerability is a function of exposure, sensitivity, and adaptive capacity then in quantifying vulnerability, it is essential to recognize how these factors combine and interact at different scales within the system. For example at the scale of an individual crop, we can assess how changes in yield are affected by rising temperatures or drought, how sensitive the crop is to temperature or drought stress, and what potential adaptations might be practical at the scale of the crop (e.g., changing sowing dates, using different crop cultivars etc.) An alternative but complimentary approach is to assess contextual vulnerability, which incorporates the socio-political and economic context alongside climate change in evaluating the security of a human system (such as a farm, farming community or regional economy).\ 
}, author = {Caitriana Steele and A. Rango and Emile H. Elias and J.T. Reyes} } @article {JRN54653, title = {Application of ecological site information to transformative changes on Great Basin sagebrush rangelands}, journal = {Rangelands}, volume = {38(6):379-388}, year = {2016}, abstract = {

Ecological Site Description (ESD) concepts are broadly applicable and provide a necessary framework to inform and guide rangeland management decisions. \ In this paper, we demonstrate how understanding and quantification of key vegetation, hydrology, and soil relationships in the ESD context can inform rangeland assessments and targeting of management practices in Great Basin sagebrush steppe. \ For the example presented here, integration of vegetation and relative estimates of runoff and erosion into the STM or ESD context identifies the ecohydrologic ramifications of each state transition and allows for more informed understanding of short- and long-term site responses to various management alternatives. \ We did not consider other factors important to a land management decision process, such as land use designations or goals, cost and practicality of treatment alternatives, resource availability, and broader area management objectives, however, such information is easily accommodated into an ESD-based decision-making strategy/framework. \ Although we present a single site-specific application, the same approach can be applied at the landscape scale. \ RHEM model scenarios and ecohydrologic interpretations could be developed for selected states across multiple ecological sites at the landscape-scale. \ RHEM is also the hillslope hydrology and erosion engine for the KINEROS2/AGWA model which enables simultaneous RHEM simulations across all hillslopes in one or more watersheds. \ Model results supplementing current ESD information could be used to target and optimize conservation efforts across multiple sites for maximum ecological and economic benefit. \ For example, tree removal may be more effective at locations with vegetation early in the juniper encroachment gradient and that have highly erodible soils. \ An integrated ESD-RHEM approach across multiple sites would equip a decision maker to predict potential site responses and most effectively implement resources across a landscape. \ The general approach presented here is not limited to sagebrush rangelands or to hydrologic and erosion processes. \ We demonstrate how enhancement of ESDs with key ecohydrologic information can aid predictions of ecosystem response and targeting of conservation practices for sloping sagebrush rangelands that are strongly regulated by ecohydrologic or ecogeomorphic feedbacks. \ Similar approaches could be applied to other rangeland ecosystems with other self-regulating processes, disturbances, and factors (e.g., wind erosion and evaporation on bare soils in flat terrain). We acknowledge that application of our approach may be difficult for sites with limited local knowledge and available data. \ Building and assessing ecological models and predicting plant community and ecohydrologic responses to disturbances and management are inherently more difficult in cases with limited information. \ A primary point of this work is that ESD concepts are flexible and can be creatively augmented for improved assessment and management of rangelands.

}, doi = {10.1016/j.rala.2016.10.004}, url = {files/bibliography/16-032.pdf}, author = {Jebediah C. Williamson 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 Hernandez Narvaez, Mariano and Wei, Haiyan and Polyakov, Viktor and G. Armendariz and Nouwakpo, S and Stuart P. Hardegree and Patrick E. Clark and Strand, Eva K. and Bates, Jonathan D. and Loretta Metz and M. H. Nichols} } @article {JRN54501, title = {Assessing climate change impacts on water availability of snowmelt-dominated basins of the Upper Rio Grande Basin}, journal = {Journal of Hydrology: Regional Studies }, volume = {3}, year = {2015}, month = {05/2015}, pages = {525-546}, chapter = {525}, abstract = {

Study Region- Upper Rio Grande, Colorado and New Mexico, USA: Climate change is predicted to further limit the water availability of the arid southwestern U.S. In this study, the Snowmelt Runoff Model is used to evaluate impacts of increased temperature and altered precipitation on snow covered area, streamflow timing and seasonal and total volume in the Upper Rio Grande.\  Simulations investigate a fairly hot and dry future condition at the end of the 21st century using a regionally recommended general circulation model downscaled to existing climate stations. Twenty-four subbasins of the Upper Rio Grande containing appreciable snowmelt and a long-term gauging station are simulated. \ \ New Hydrological Insights for the Region: Total basin snow covered area decreased by 55\% due to future temperatures. SRM simulation shows that total annual 2099 volume for all basins was between 13\% and 33\% lower than 1999 total annual volume. Among the 24 basins there is considerable range in decrease in snow covered area (6-87\%), total volume reduction (4-34\%) and runoff timing shift (0-60 days early) indicating that climate change impacts are best evaluated at the sub-basin scale. Daily hydrographs show higher streamflow in March and April, but less from mid-May until the end of the water year.\  The large decrease in volume in May, June and July will compound water management challenges in the Upper Rio Grande.

}, keywords = {climate change, snowmelt runoff model, Upper Rio Grande, water resources}, doi = {10.1016/j.ejrh.2015.04.004}, url = {/files/bibliography/15-021.pdf}, author = {Emile H. Elias and A. Rango and Caitriana Steele and Mejia, John and Ryann Smith} } @conference {JRN54496, title = {AERO: A decision support tool for wind erosion assessment in rangelands and croplands}, booktitle = {AGU Fall Meeting}, year = {2015}, month = {12/2015}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {San Francisco, CA}, abstract = {

Wind erosion is a key driver of global land degradation, with on- and off-site impacts on agricultural production, air quality, ecosystem services and climate. Measuring rates of wind erosion and dust emission across land use and land cover types is important for quantifying the impacts and identifying and testing practical management options. This process can be assisted by the application of predictive models, which can be a powerful tool for land management agencies. The Aeolian EROsion (AERO) model, a wind erosion and dust emission model interface provides access by non-expert land managers to a sophisticated wind erosion decision-support tool. AERO incorporates land surface processes and sediment transport equations from existing wind erosion models and was designed for application with available national long-term monitoring datasets (e.g. USDI BLM Assessment, Inventory and Monitoring, USDA NRCS Natural Resources Inventory) and monitoring protocols. Ongoing AERO model calibration and validation are supported by geographically diverse data on wind erosion rates and land surface conditions collected by the new National Wind Erosion Research Network. Here we present the new AERO interface, describe parameterization of the underpinning wind erosion model, and provide a summary of the model applications across agricultural lands and rangelands in the United States.

}, author = {Magda Galloza and Nicholas Webb and Jeffrey E. Herrick} } @article {JRN54514, title = {Application of spatial pedotransfer functions to understand soil modulation of vegetation response to climate}, journal = {Vadose Zone Journal}, volume = {14}, year = {2015}, month = {09/2015}, pages = {1-14}, chapter = {1}, abstract = {

A fundamental knowledge gap in understanding land-atmosphere interactions is accurate, high resolution spatial representation of soil physical and hydraulic properties. We present a novel approach to predict hydraulic soil parameters by combining digital soil mapping techniques with pedotransfer functions and demonstrate that simple derived quantities are related to observed spatial patterns in ecosystem production during the North American Monsoon. Landsat reflectance and elevation data were used to predict physical soil properties at a 5 m spatial resolution for a semiarid landscape of 6,265 ha using regression kriging. Resulting soil property maps were applied to the Rosetta pedotransfer function to predict saturated hydraulic conductivity and water retention parameters from which approximate water residence times were derived. Estimated idealized residence time for water lost to the deeper vadose zone and evapotranspiration corresponded to vegetation response. Antecedent precipitation was more important for explaining the relationships between modeled soil properties and vegetation response than the amount of monsoon precipitation. Increased spring precipitation prior to the monsoon produced stronger negative correlations with hydraulic conductivity and stronger positive correlations with plant available water. Modeled water residence times explained the patterns of vegetation and landscape morphology validating our approach as a method of producing functional spatial pedotransfer functions. Linking digital soil mapping with Rosetta led to predictions of hydraulic soil properties that were more closely related to vegetation dynamics compared to data available in the SSURGO soil database.

}, doi = {10.2136/vzj2014.09.0126}, url = {/files/bibliography/15-022.pdf}, author = {Matthew Levi and Schaap, Marcel and Craig Rasmussen} } @article {JRN54095, title = {Australian net (1950s-1990) soil organic carbon erosion: implications for CO2 emission and land-atmosphere modelling}, journal = {Biogeosciences}, volume = {11}, year = {2014}, month = {09/2014}, pages = {5235-5244}, chapter = {5235}, abstract = {

The debate remains unresolved about soil erosion substantially offsetting fossil fuel emissions and acting as an important source or sink of CO2. There is little historical land use and management context to this debate, which is central to Australia\&$\#$39;s recent past of European settlement, agricultural expansion and agriculturally induced soil erosion. We use \"catchmen\" scale (25 km2) estimates of 137Cs-derived net (1950s\–1990) soil redistribution of all processes (wind, water and tillage) to calculate the net soil organic carbon (SOC) redistribution across Australia.\  We approximate the selective removal of SOC at net eroding locations and SOC enrichment of transported sediment and net depositional locations. We map net (1950s\–1990) SOC redistribution across Australia and estimate erosion by all processes to be 4 Tg SOC yr-1, which represents a loss of 2\% of the total carbon stock (0\–10 cm) of Australia. Assuming this net SOC loss is mineralised, the flux (15 TgCO2-equivalents yr-1) represents an omitted 12\% of CO2-equivalent emissions from all carbon pools in Australia. Although a small source of uncertainty in the Australian carbon budget, the mass flux interacts with energy and water fluxes, and its omission from land surface models likely creates more uncertainty than has been previously recognized.

}, doi = {10.5194/bg-11-5235-2014}, url = {/files/bibliography/14-030.pdf}, author = {A. Chappell and Nicholas Webb and Raphael A. Viscarr Rossel and Bui, Elisabeth} } @article {JRN53943, title = {Asymmetric ecological and economic responses for rangeland restoration: A case study of tree thickening in Queensland, Australia}, journal = {Rangelands}, volume = {36}, year = {2014}, month = {04/2014}, pages = {37-44}, chapter = {37}, abstract = {

Economic motivation for implementing targeted responses to rangeland degradation often lag the events that cause degradation and\  existing monitoring schemes often lack the sensitivity or the connections to ecological processes to reliably serve as a basis for evaluating success. In this paper, we present an approach for quantifying the relationship of economic output and land degradation during the intermediate stages of degradation. We also propose an approach that can provide enhanced incentives to implement proven responses before degradation processes are entrained.

}, keywords = {bio-economic modelling, ecological thresholds, economic thresholds, prescribed fire, ranching, rangeland rehabilitation, timber thickening}, doi = {10.2111/rangelands-d-13-00074.1}, url = {/files/bibliography/14-011.pdf}, author = {MacLeod, Neil and Scanlan, Joe C. and Joel R. Brown} } @article {JRN53971, title = {AIM-Monitoring: a component of the BLM assessment, inventory, and monitoring strategy}, year = {2014}, pages = {11 p.}, publisher = {Bureau of Land Management, National Operations Center}, abstract = {

The \“BLM Assessment, Inventory, and Monitoring Strategy for Integrated Renewable Resources Management\” (AIM Strategy) was completed in 2011 in response to a request from the Office of Management and Budget. The strategy describes an approach for integrated, cross-program assessment, inventory, and monitoring of renewable resources (e.g., vegetation, soils, water, and wildlife habitat) at multiple scales of management. Following the AIM Strategy, the BLM is modernizing its resource monitoring approach to more efficiently and effectively meet local, regional, and national resource information needs. The AIM Strategy provides a process for the BLM to collect quantitative information on the status, condition, trend, amount, location, and spatial pattern of renewable resources on the nation\’s public lands, from individual field office levels, to public lands across the Western U.S. and Alaska. Each AIM-Monitoring survey, at any scale of inquiry, uses a set of core\  indicators, standardized field methods, remote sensing, and a statistically valid study design to provide nationally consistent and scientifically defensible information to track changes on public lands over time.

}, issn = {Technical Note 445}, url = {/files/bibliography/14-018.pdf}, author = {Jason Taylor and Gordon R. Toevs and Jason W. Karl and Matthew Bobo and Michael S. Karl and Scott W. Miller and Carol Spurrier} } @article {49836, title = {Assessing resilience and state-transition models with historical records of cheatgrass Bromus tectorum invasion in North American sagebrush-steppe}, journal = {Journal of Applied Ecology}, volume = {50}, year = {2013}, month = {09/2013}, pages = {1131-1141}, chapter = {1131}, abstract = {

1. Resilience-based approaches are increasingly being called upon to inform ecosystem management, particularly in arid and semi-arid regions. This requires management frameworks that can assess ecosystem dynamics, both within and between alternative states, at relevant time scales.

2. We analysed long-term vegetation records from two representative sites in the North American sagebrush-steppe ecosystem, spanning nine decades, to determine if empirical patterns were consistent with resilience theory, and to determine if cheatgrass Bromus tectorum invasion led to thresholds as currently envisioned by expert-based state-and-transition models (STM). These data span the entire history of cheatgrass invasion at these sites and provide a unique opportunity to assess the impacts of biotic invasion on ecosystem resilience.

3. We used univariate and multivariate statistical tools to identify unique plant communities and document the magnitude, frequency and directionality of community transitions through time. Community transitions were characterized by 37{\textendash}47\% dissimilarity in species composition, they were not evenly distributed through time, their frequency was not correlated with precipitation, and they could not be readily attributed to fire or grazing. Instead, at both sites, the majority of community transitions occurred within an 8{\textendash}10 year period of increasing cheatgrass density, became infrequent after cheatgrass density peaked, and thereafter transition frequency declined.

4. Greater cheatgrass density, replacement of native species and indication of asymmetry in community transitions suggest that thresholds may have been exceeded in response to cheatgrass invasion at one site (more arid), but not at the other site (less arid). Asymmetry in the direction of community transitions also identified communities that were {\textquoteleft}at-risk{\textquoteright} of cheatgrass invasion, as well as potential restoration pathways for recovery of pre-invasion states.

cheatgrass, Bromus tectorum, community transitions, dynaimc regime, ecological resilience, ecosystem manasgement, invasive species, rangelands, resilience-based management, thresholds, Artemisia, sagebrush-steppe

5. Synthesis and applications. These results illustrate the complexities associated with threshold identification, and indicate that criteria describing the frequency, magnitude, directionality and temporal scale of community transitions may provide greater insight into resilience theory and its application for ecosystem management. These criteria are likely to vary across biogeographic regions that are susceptible to cheatgrass invasion, and necessitate more in-depth assessments of thresholds and alternative states, than currently available.

}, keywords = {Artemisia, Bromus tectorum, cheatgrass, community transitions, dynaimc regime, ecological resilience, ecosystem manasgement, invasive species, rangelands, resilience-based management, sagebrush-steppe, thresholds}, doi = {10.1111/1365-2664.12128}, url = {/files/bibliography/13-026.pdf}, author = {Bagchi, Sumanta and D.D. Briske and Brandon T Bestelmeyer and X. Ben Wu} } @article {49846, title = {Assessing impacts of roads: Application of a standard assessment protocol}, journal = {Rangeland Ecology and Management}, volume = {66}, year = {2013}, month = {05/2013}, pages = {364-375}, chapter = {364}, abstract = {

Adaptive management of road networks depends on timely data that accurately reflect the impacts of network impacts on ecosystem processes and associated services. In the absence of reliable data, land managers are left with little more than observations and perceptions to support adaptive management of road-associated disturbances. Roads can negatively impact the soil, hydrologic, plant, and animal processes on which virtually all ecosystem services depend. The Interpreting Indicators of Rangeland Health (IIRH) protocol is a qualitative method that has been demonstrated to be effective in characterizing impacts of roads. The goals of this study were to develop, describe, and test an approach for using IIRH to systematically evaluate road impacts across large, diverse arid and semiarid landscapes. We developed a stratified random sampling approach to plot selection based on ecological potential, road inventory data, and image interpretation of road impacts. The test application on a semi-arid landscape in southern New Mexico, USA demonstrates that the approach developed is sensitive to road impacts across a broad range of ecological sites but that not all the types of stratification were useful. Ecological site and road inventory strata accounted for significant variability in the functioning of ecological processes but stratification based on apparent impact did not. Analysis of the repeatability of IIRH applied to road plots indicates that the method is repeatable but consensus evaluations based multiple observers should be used to minimize risk of bias. Landscape-scale analysis of impacts by roads of contrasting designs (maintained dirt or gravel roads versus non- or infrequently maintained roads) suggests that future travel management plans for the study area should consider concentrating traffic on fewer roads that are well-designed and maintained. Application of the approach by land managers will likely provide important insights into minimizing impacts of road networks on key ecosystem services.

}, keywords = {adaptive management, assessment, monitoring, off-highway vehicles, oil and gas, rangeland health}, doi = {10.2111/REM-D-11-00130.1}, url = {/files/bibliography/13-018.pdf}, author = {Danielle Duni and Jeffrey E. Herrick} } @inbook {JRN52686, title = {Adaptive management of grazing lands}, booktitle = {Dryland East Asia, Land Dynamics Amid Social and Climate Change}, year = {2013}, pages = {447-464}, publisher = {Higher Education Press}, organization = {Higher Education Press}, chapter = {19}, address = {Beijing, China}, abstract = {

Rangelands, the mainland type used as grazing lands, occupy ~54\% of the world{\textquoteright}s ice-free land surface, and grasslands dominate ~ 16\% of all rangelands.\  China is the third largest country for rangeland resources in the world and has approximately 400 million ha rangeland, about 40\% of China{\textquoteright}s land surface.\  These grazing lands are susceptible to severe degradation due to overexploitation, especially, overgrazing.\  This chapter provides an overview of the geographic distribution and management issues of these grazing lands, and a case study on adaptive management in an innovative grazing system in desert steppe of Inner Mongolia Autonomous Region (IM), China.\  We emphasize the importance of applying models and management demonstration related to stocking rate reduction, lambing time change and the use of warm shed based on household to prevent resource degradation.\  We discuss the interaction of ecological and economic benefits in the application of grazing systems for desert steppe areas.\  We provide evidence for the use of an innovative adaptive management practice based on development of a summer grazing system with low stock rate and winter warm shed feeding.

}, author = {G. Han and Liu, Tong and Zhongwu Wang and Li, Zhiguo and Mengli Zhao and Kris Havstad and Jianguo Wu and Kemp, David} } @conference {JRN53996, title = {Adapting to climate change and disaster risk reduction through sustainable land management: Experiences in Tajikistan, East Africa, US, Argentina and Mongolia}, booktitle = {UNCCD 2nd Scientific Conference}, year = {2013}, month = {04/2013}, address = {Bonn, Germany}, abstract = {

The special session will share and discuss experiences from different regions, namely from Tajikistan, East Africa, US, Argentina and Mongolia. Within the Pilot Program for Climate Resilience (PPCR) in Tajikistan 70 SLM technologies and approaches on how to implement SLM were documented with the World Overview of Conservation Approaches and Technologies (WOCAT \– www.wocat.net) tools in 2011. Initial results will be presented. Furthermore, a general approach for resilience-based management in the US, Argentina, and Mongolia, taking advantage in several new natural resource management concepts and technologies will be presented with a brief reference to the development of a global system for defining land potential, that complements the work described here.

}, author = {Jeffrey E. Herrick and Gordon R. Toevs} } @article {JRN54874, title = {Acequias and the Effects of Climate Change}, year = {2013}, abstract = {

Traditional forms of acequia irrigation can be combined with ground based and remote sensing snow measurements and snowmelt runoff modeling to better estimate runoff volumes now and in the future under conditions of climate change. The experience gained over 400 years of irrigating small fields strongly binds communities and strengthens the resolve of acequia associations to contest challenges presented by climate change. Increased density of snow measurements in high elevations of the Rio Grande along with input of real-time data to snowmelt models has led to an improved potential for acequia decision making under the increased temperatures projected for the future by climate models. Acequia communities and similar Native American settlements have shown the willingness to share water during times of severe water shortages in the southwestern U.S. Acequia associations have shown the desire to adopt new forms of hydrologic data and modeling techniques and incorporate them into acequia association approaches.

}, keywords = {Acequias, climate change, snowmelt runoff modeling}, doi = {10.1111/j.1936-704X.2013.03154.x}, url = {/files/bibliography/13-042.pdf}, author = {A. Rango and Alexander Fernald and Caitriana Steele and Hurd, B. and Carlos Ochoa} } @article {49868, title = {Aeolian process effects on vegetation communities in an arid grassland ecosystem}, journal = {Ecology and Evolution}, volume = {2}, year = {2012}, month = {04/01/2012}, pages = {809-821}, abstract = {

Many arid grassland communities are changing from grass dominance to shrub dominance, but the mechanisms involved in this conversion process are not completely understood. Aeolian processes likely contribute to this conversion from grassland to shrubland. The purpose of this research is to provide information regarding how vegetation changes occur in an arid grassland as a result of aeolian sediment transport. The experimental design included three treatment blocks, each with a 25 {\texttimes} 50 m area where all grasses, semi-shrubs, and perennial forbs were hand removed, a 25 {\texttimes} 50 m control area with no manipulation of vegetation cover, and two 10 {\texttimes} 25 m plots immediately downwind of the grass-removal and control areas in the prevailing wind direction, 19{\textdegree} north of east, for measuring vegetation cover. Aeolian sediment flux, soil nutrients, and soil seed bank were monitored on each treatment area and downwind plot. Grass and shrub cover were measured on each grass-removal, control, and downwind plot along continuous line transects as well as on 5 {\texttimes} 10 m subplots within each downwind area over four years following grass removal. On grass-removal areas, sediment flux increased significantly, soil nutrients and seed bank were depleted, and Prosopis glandulosa shrub cover increased compared to controls. Additionally, differential changes for grass and shrub cover were observed for plots downwind of vegetation-removal and control areas. Grass cover on plots downwind of vegetation-removal areas decreased over time (2004{\textendash}2007) despite above average rainfall throughout the period of observation, while grass cover increased downwind of control areas; P. glandulosa cover increased on plots downwind of vegetation-removal areas, while decreasing on plots downwind of control areas. The relationships between vegetation changes and aeolian sediment flux were significant and were best described by a logarithmic function, with decreases in grass cover and increases in shrub cover occurring with small increases in aeolian sediment flux.

}, keywords = {aeolian processes, grassland community, sediment flux, seed bank, soil nutrients, vegetation change, vegetation community, vegetation cover}, doi = {10.1002/ece3.205}, url = {/files/bibliography/12-020.pdf}, author = {Lorelei Alvarez and Howard Epstein and Junran Li and Gregory S. Okin} } @proceedings {JRN54542, title = {Australian carbon dust emission: a carbon accounting omission?}, volume = {Sequestration - Accounting}, year = {2012}, month = {12/2012}, publisher = {Australian Society of Soil Science Conference}, address = {Hobart Tasmania}, abstract = {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 redistribution are not considered in most SOC models, or within the Australian national carbon accounting scheme. Although SOC can be redistributed locally by water and wind erosion, dust emission can remove surface SOC from vast areas of inland and agricultural areas of Australia and transport it quickly offshore; representing a net loss of SOC from terrestrial systems. Estimates of the carbon dust emission magnitude require information on the spatial and temporal variation of SOC enrichment in dust emissions (P). We developed a process-based approximation of P within the Computational Environmental Management System (CEMSYS v5) national wind erosion model. It enabled the prediction of carbon dust emissions at a 50 km spatial resolution across Australia every month from 2000{\textendash}2010. Carbon dust emissions were summed for all months in the study period and across Australia to generate a time series of national carbon dust emissions. The magnitude, frequency and spatial variation of carbon dust emissions and their implications for Australian national carbon accounts will be discussed.}, author = {A. Chappell and Nicholas Webb and Harry Butler and Craig Strong and Grant McTainish and John Leys} } @article {49881, title = {Animal foraging as a mechanism for sediment movement and soil nutrient development: Evidence from the semi-arid Australian woodlands and the Chihuahuan Desert}, journal = {Geomorphology}, volume = {157-158}, year = {2012}, month = {01/01/2012}, pages = {131-141}, chapter = {131}, abstract = {

An emerging area of interest in geomorphology over the past two decades has been the effects of biota on ecosystemprocesses.We examined the roles of a rangeof vertebrates on soil disturbance in two markedly different environments, the semi-arid woodland of eastern Australia and a Chihuahuan Desert grassland{\textendash}shrubland in the south-western United States. Foraging pits of soil-disturbing vertebrates varied markedly from small scratchings of heteromyid (mainly Dipodomys spp.) rodents (1.8{\texttimes}10-4m3) to deep (1.0{\texttimes}10-2 m3) excavations of the burrowing bettong (Bettongia leuseur) and greater bilby (Macrotis lagotis). Vertebrates moved substantial volumes of soil in both environments, and activity was highly temporally and spatially variable. At large spatial scales, soil disturbance by echidnas (Tachyglossus aculeatus) and Gould{\textquoteright}s sand goannas (Varanus gouldii) was substantially greater in communities dominated by shrubs, and where domestic livestock had been excluded. Heteromyid rodents tended to excavate more foraging pits in coarse-textured vegetation communities (both grasslands and shrublands). In both environments, foraging was concentrated close to perennial plants such as grass tussocks and tree canopies rather than in the interspaces. Foraging pits of Chihuahuan desert animals tended to be higher in labile carbon and support greater levels of infiltration, though this was plant community-dependent. Overall our results indicate that animal foraging is an important geomorphic mechanism capable of mobilizing substantial volumes of soil in arid and semi-arid environments and with potential effects on soil function. {\textcopyright} 2011 Elsevier B.V. All rights reserved.

}, keywords = {arid, Australia, Biopedturbation, foraging, Jornada, patchiness, rodents, soil formation, soil movement, vertebrates}, doi = {10.1016/j.geomorph.2011.04.041}, url = {/files/bibliography/12-016.pdf}, author = {D.J. Eldridge and T. B. Koen and Aaron Killgore and Huang, Niki and Walter G. Whitford} } @proceedings {JRN54549, title = {Applying animal behavior to arid rangeland mangement}, volume = {pg. 44-45}, year = {2012}, month = {05/2012}, publisher = {Wildland Shrub Symposium}, address = {Las Cruces, NM}, abstract = {Livestock production is one of many demands placed on today{\textquoteright}s arid rangelands. Therefore, understanding plant and animal biology and their effects on biotic and abiotic landscape components is fundamental if rangelands are to remain ecologically sustainable. One limiting factor to accomplishing positive change on animal dominated landscapes is an incomplete understanding of animal behavior needed to efficiently manipulate and achieve management goals. Livestock differ anatomically and physiologically in their ability to utilize heterogeneous landscapes. The proper stocking of arid landscapes simultaneously with cattle, sheep and goats allows maximum plant biomass to be converted into food and fiber. However, this species mix is not always practical due to predation losses that can occur with small ruminants. Research has clearly demonstrated that by modifying innate animal behaviors, mixed-species groups can be managed successfully using flerds (flocks + herds). Furthermore, today{\textquoteright}s technology based on systems such as the global positioning system (GPS) offers exciting mechanisms to tie the spatial and temporal dynamics of plants and animals together to foster proactive management of livestock distribution and animal control in real time. Gene pools within livestock species that have had little influence from human selection such as Criollo cattle offer further exciting possibilities for creating designer animals that match the conditions of arid rangeland landscapes. These and other studies have characterized the Jornada{\textquoteright}s animal based research over the past 100 years.}, author = {Amy L. Gonzalez and Richard E. Estell and D.M. Anderson} } @article {49891, title = {An accounting of C-based trace gas release during abiotic plant litter degradation}, journal = {Global Change Biology}, volume = {18}, year = {2012}, pages = {1185-1195}, abstract = {

Recent studies showed that photochemical breakdown (photodegradation) of plant material accounts for a substantial portion of litter decomposition and subsequent trace gas release in ecosystems under high radiative load and low precipitation. In the absence of solar radiation, thermal degradation may also cause trace gas release at temperatures below the ignition point. These observations suggest that the abiotic processes of photodegradation and thermal degradation of plant litter may be important in understanding global trace gas budgets. In a laboratory incubation study, we performed a simultaneous carbon (C) accounting of CO2, CO, and CH4 produced as a byproduct of photodegradation and thermal degradation of six different plant litter types that varied in chemical composition. The patterns of trace gas release during photodegradation and thermal degradation differed considerably across the six plant materials, suggesting that chemical composition of litter may influence the rates of abiotic degradation. There was a strong positive correlation between the rates of trace gas release during photodegradation and temperature. A significant portion of trace gases were produced during low temperature (\<\ 100\ {\textdegree}C) thermal degradation of litter in the absence of solar radiation, which was also positively correlated to temperature. In addition, both thermal degradation and photodegradation occurred in the absence of O2. This indicates that the mechanism formerly accepted as photo-oxidation may only be one of several photodegradation processes. We speculate that the direct breakdown of chemical groups such as carboxyl, carbonyl, and methoxyl groups may result in CO2, CO, and CH4 release. We suggest that the combined processes of thermal and photodegradation of litter may be a previously under accounted source of C-based trace gases from terrestrial systems.

}, keywords = {carbon dioxide, carbon monoxide, carbon-based trace gas, CH4, CO, CO2, decomposition, Jornada, litter decomposition, methane, photodegradation, plant litter, thermal degradation}, doi = {10.1111/j.1365-2486.2011.02579.x}, url = {files/bibliography/JRN00590.pdf}, author = {Hanna Lee and Rahn, Thom and Heather L. Throop} } @article {49931, title = {Analysis of abrupt transitions in ecological systems}, journal = {Ecosphere}, volume = {2}, year = {2011}, month = {12/2011}, pages = {1-26}, type = {Article 129}, chapter = {1}, abstract = {

The occurrence and causes of abrupt transitions, thresholds, or regime shifts between ecosystem states are of great concern and the likelihood of such transitions is increasing for many ecological systems. General understanding of abrupt transitions has been advanced by theory, but hindered by the lack of a common, accessible, and data-driven approach to characterizing them. We apply such an approach to 30 \– 60 years of data on environmental drivers, biological responses, and associated evidence from pelagic ocean, coastal benthic, polar marine, and semi-arid grassland ecosystems. Our analyses revealed one case in which the response (krill abundance) linearly tracked abrupt changes in the driver (Pacific Decadal Oscillation), but abrupt transitions detected in the three other cases (sea cucumber abundance, penguin abundance, and perennial grass production) exhibited hysteretic relationships with drivers (wave intensity, sea-ice duration, and amounts of monsoonal rainfall, respectively) through a variety of response mechanisms. The use of a common approach across these case studies illustrates that: the utility of leading indicators is often limited and can depend on the abruptness of a transition relative to the lifespan of responsive organisms and observation intervals; information on spatiotemporal context is useful for comparing transitions; and ancillary information from associated experiments and observations informs interpretations of response-driver relationships. The understanding of abrupt transitions offered by this approach provides information that can be used to manage state changes and underscores the utility of long-term observations in multiple sentinel sites across a variety of ecosystems.

}, keywords = {alternative states, Bouteloua eriopoda, desert grassland, krill, leading indicators, Nyctiphanes simplex, Pachythyone rubra, Penguins, Pygoscelis, regime shifts, sea cucumbers, thresholds}, doi = {10.1890/ES11-00216.1}, url = {/files/bibliography/11-036.pdf}, author = {Brandon T Bestelmeyer and Ellison, Aaron M. and William R. Fraser and Gorman, Kristen B. and Sally J. Holbrook and C. Laney and Mark D. Ohman and Debra C. Peters and Pillsbury, Finn C. and Andrew Rassweiler and Russell J. Schmitt and Sharma, Sapna} } @article {49945, title = {The association of land cover with aeolian sediment production at Jornada Basin, New Mexico, USA}, journal = {Aeolian Research}, volume = {3}, year = {2011}, pages = {55-66}, abstract = {

We investigated amounts and particle size distributions (PSDs) of aeolian sediments collected at five heights in five ecosystem types at the Jornada Basin, Chihuahuan Desert, New Mexico, USA. Particle size distributions, mass fluxes, and percent of dust-sized (650 lm) mass flux were determined for all heights and all ecosystem types. Differences between sites were determined using ANOVA followed by Tukey{\textendash}Kramer post hoc tests to find groupings. For creosote shrublands, grasslands, and two tarbush-dominated alluvial flats, samples collected at 5, 10, and 20 cm had \>80\% sand-sized (\>50 lm) particles, while one playa and tarbush site yielded ~45\% dust-sized particles at 5 and 10 cm. The transition from saltation to suspension was ~20 cm for most sites. Two mesquite dune sites and an anthropogenically devegetated site, all with high overall mass fluxes, shifted to suspension at ~50 cm. Highest dust fluxes occurred at the devegetated site, followed by the playa, a mesquite site with unvegetated {\textquoteleft}{\textquoteleft}streets,{\textquoteright}{\textquoteright} and tarbush sites.
These field observations are consistent with laboratory-based dust emission experiments and remote sensing studies in the Chihuahuan Desert. Playas and tarbush sites are major dust producers due to high proportions of fines, whereas the mesquite site produces much dust because of greater overall mass flux. Mesquite dunes covering most of the basin likely produce the most dust overall, though playas and tarbush-
dominated alluvial flats (which cover about 8\%) can emit large amounts of dust. Continuing shrubland encroachment will likely increase dust emissions from the Jornada Basin, as well as in other arid regions. {\textcopyright} 2011 Elsevier B.V. All rights reserved.10.1016/j.aeolia.2011.02.002

}, keywords = {BSNE, Chihuahuan Desert, dust collection, dust flux, Jornada Basin LTER, land cover, NPP sites, particle size, sand transport, vegetation communities}, doi = {10.1016/j.aeolia.2011.02.002}, url = {files/bibliography/JRN00587.pdf}, author = {Floyd, Kevin W. and Thomas E. Gill} } @proceedings {JRN54545, title = {Agroecohydrology: Key to feeding 9 billion?}, volume = {Control ID 1211464}, year = {2011}, month = {07/2012}, publisher = {American Geophysical Union}, address = {San Francisco, CA}, abstract = {Agricultural production necessary to feed 9 billion people in 2050 depends on increased production on existing croplands, and expanding onto {\textquoteleft}marginal{\textquoteright} lands. A high proportion of these lands are marginal because they are too steep or too dry to reliably support crop production. These same characteristics increase their susceptibility to accelerated erosion, leading (for most soil profiles) to further reductions in plant available water as infiltration and soil profile water holding capacity decline. Sustaining production on these marginal lands will require careful land use planning. In this paper, we present a land use planning framework that integrates 4 elements: (1) potential production (based on soil profile characteristics), (2) edaphic, topographic and climatic limitations to production, (3) soil resistance to degradation, and (4) resilience. This framework expands existing land capability classification systems through the integration of biophysical feedbacks and thresholds. State and transition models, similar to those currently applied to rangelands in the United States and other countries, are used to organize and communicate knowledge about the sustainability of different land use changes and management actions at field to regional scales. This framework emphasizes hydrologic characteristics of soil profiles and landscapes over fertility because fertility declines are more easily addressed through increased inputs. The presentation will conclude with a discussion of how research in ecohydrology can be more effectively focused to support sustainable food production in the context of increasingly rapid social and economic changes throughout the world.}, author = {Jeffrey E. Herrick} } @proceedings {49947, title = {Are we ready for the (range)land revolution?}, year = {2011}, month = {04/2011}, address = {Rosario, Argentina}, abstract = {

Rangeland scientists have a tremendous amount of knowledge that could ensure that the transition from livestock production to other land uses is as sustainable as possible, while maintaining livestock production systems where they are the most biophysically, socially, culturally and economically sustainable option. The rate and extent of these land use changes, however, will require a new approach to our science and how we communicate it. We can increase our ability to contribute to the future management of these lands through (1) increased awareness of global social, economic, and technological trends, (2) research and modeling that anticipate the potential effects of large-scale changes in land cover and land use on ecosystem services across a wide variety of soils, landforms and climate conditions, and (3) dramatically increased communication and collaboration with the disciplines and sectors of society responsible for managing the new land uses.

}, keywords = {rangeland}, author = {Jeffrey E. Herrick and S. Andrews and Baldi, G. and Brandon T Bestelmeyer and Joel R. Brown and J. Davis and Danielle Duni and Kris Havstad and Debra C. Peters and Quinton, J. N. and C. Riginos and P. L. Shaver and Diego Steinaker and Twomlow, S.} } @article {49954, title = {An assessment of state-and-transition models: Perceptions following two decades of development and implementation}, journal = {Rangeland Ecology \& Management}, volume = {64}, year = {2011}, month = {11/2011}, pages = {598-606}, chapter = {598}, abstract = {

State and transition models (STMs) are being developed for many areas in the United States and represent an important tool for assessing and managing public and private rangelands. Substantial resources have been invested in model development, yet minimal efforts have been made to evaluate the utility of STMs for rangeland assessment and management. We interviewed 47 rangeland professionals, equally divided between managers and researchers, in four ecoregions to determine their perceptions of the purpose, development, and strengths and weaknesses of STMs to assess the status of the STM framework. Our analysis identified three primary perspectives regarding the purpose of STMs: a decision-making tool for land managers, a means to represent the complex dynamics of rangeland ecosystems, and an effective communication tool. These diverse views of STM purposes were associated with differing perspectives concerning model development that identified five major issues in need of further development and refinement: 1) the relative importance of management practices and ecological processes in driving transitions, 2) the criteria used to define thresholds, 3) the appropriate level of model complexity, 4) the respective roles of expert knowledge and ecological data in model development, and 5) processes for model review and revision. We recommend greater dialogue among researchers and managers to further clarify STM terminology and develop standard protocols for model development and validation. Mechanisms are critically needed to assure peer review and revision of existing models so that STMs are continually updated to reflect current understanding of rangeland dynamics.

}, doi = {10.2111/REM-D-10-00188.1}, url = {/files/bibliography/11-037.pdf}, author = {Corrine Knapp and Maria Fern{\'a}ndez-Gim{\'e}nez and D.D. Briske and Brandon T Bestelmeyer and X. Ben Wu} } @inbook {49964, title = {Aridisols}, booktitle = {Handbook of Soil Science}, year = {2011}, pages = {33-125 to 33-154}, publisher = {CRC Press}, organization = {CRC Press}, edition = {2nd}, address = {Boca Raton}, keywords = {aridisols, soil classification}, author = {Curtis H. Monger and Southard, R. J. and Boettinger, J. L.} } @article {49986, title = {Aolian processes and the biosphere}, journal = {Reviews of Geophysics}, volume = {49}, year = {2011}, pages = {RG3001}, abstract = {

[1] Aeolian processes affect the biosphere in a wide variety of contexts, including landform evolution, biogeochemical cycles, regional climate, human health, and desertification. Collectively, research on aeolian processes and the biosphere is developing rapidly in many diverse and specialized areas, but integration of these recent advances is needed to better address management issues and to set future research priorities. Here we review recent literature on aeolian processes and their interactions with the biosphere, focusing on (1) geography of dust emissions, (2) impacts, interactions, and feedbacks, (3) drivers of dust emissions, and (4) methodological approaches. Geographically, dust emissions are highly spatially variable but also provide connectivity at global scales between sources and effects, with {\textquotedblleft}hot spots{\textquotedblright} being of particular concern. Recent research reveals that aeolian processes have impacts, interactions, and feedbacks at a variety of scales, including large-scale dust transport and global biogeochemical cycles, climate mediated interactions between atmospheric dust and ecosystems, impacts on human health, impacts on agriculture, and interactions between aeolian processes and dryland vegetation. Aeolian dust emissions are driven largely by, in addition to climate, a combination of soil properties, soil moisture, vegetation and roughness, biological and physical crusts, and disturbances. Aeolian research methods span laboratory and field techniques, modeling, and remote sensing. Together these integrated perspectives on aeolian processes and the biosphere provide insights into management options and aid in identifying research priorities, both of which are increasingly important given that global climate models predict an increase in aridity in many dryland systems of the world.

}, keywords = {aeolian processes, biogeochemistry, biosphere, drivers, dust emissions, ecosystem dynamics, feedbacks, impacts, interactions, methods}, doi = {10.1029/2010RG000328 }, url = {files/bibliography/JRN00552.pdf}, author = {S. Ravi and Paolo D{\textquoteright}Odorico and David D. Breshears and J. P. Field and A.S. Goudie and T. Huxman and Junran Li and Gregory S. Okin and Swap, Robert J. and Thomas, Andrew D. and Scott Van Pelt and J. J. Whicker and Teddy M. Zobeck} } @conference {JRN54460, title = {Autonomous gathering of livestock using a multi-functional sensor network platform}, booktitle = {Hot Topics in Embedded Networked Sensors}, year = {2010}, month = {06/2010}, address = {Killarney, Ireland}, abstract = {

In this paper we develop algorithms and hardware for the autonomous gathering of cattle. We present a comparison of three different autonomous gathering algorithms that employ sound and/or electric stimuli to guide the cattle. We evaluate these algorithms in simulation by extending previous behavioral simulations for cattle.\  We implemented one of these algorithms and present data from experiments in which cattle were equipped with sensor nodes that allowed cueing with sound and electric stimuli. We discuss the minimum requirements for algorithms and hardware for autonomous gathering.

}, url = {/files/bibliography/10-020.pdf}, author = {Marek Doniec and Detweiler, C. and Vasilescu, L. and D.M. Anderson and D. Rus} } @article {50024, title = {Assessing transportation infrastructure impacts on rangelands: Test of a standard rangeland assessment protocol}, journal = {Rangeland Ecology and Management}, volume = {63}, year = {2010}, month = {07/2010}, pages = {524-536}, chapter = {524}, abstract = {

Linear disturbances associated with on and off-road vehicle use on rangelands has increased dramatically throughout the world in recent decades. This increase is due to a variety of factors including increased availability of all-terrain vehicles, infrastructure development (oil, gas, renewable energy, and ex-urban) and recreational activities. In addition to the direct impacts of road development, the presence and use of roads may alter resilience of adjoining areas through indirect effects such as altered site hydrologic and eolian processes, invasive seed dispersal, and sediment transport. There are few standardized methods for assessing impacts of transportation-related land-use activities on soils and vegetation on arid and semi-arid rangelands. Interpreting Indicators of Rangeland Health (IIRH) is an internationally accepted qualitative assessment that is applied widely to rangelands. We tested the sensitivity of IIRH to impacts of roads, trails, and pipelines on adjacent lands by surveying plots at three distances from these linear disturbances. We performed tests at 16 randomly selected sites in each of 3 ecosystems (Northern High Plains, Colorado Plateau, and Chihuahuan Desert) for a total of 208 evaluation plots. We also evaluated the repeatability of IIRH when applied to road-related disturbance gradients. Finally, we tested the extent to which IIRH plot attribute departure classes are correlated with trends in a suite of quantitative indicators. Results indicated that the IIRH technique is sensitive to direct and indirect impacts of transportation activities. Trends in degradation detected with qualitative assessments were highly correlated with quantitative data. Qualitative and quantitative assessments employed in this study can be used to assess impacts of transportation features at the plot scale. Through integration with remote sensing technologies, these methods could also potentially be used to assess cumulative impacts of transportation networks at the landscape scale.

}, keywords = {disturbance, IIRH, indicators, off-highway vehicles, oil and gas, rangeland health, roads}, doi = {10.2111/REM-D-09-00176.1}, url = {/files/bibliography/10-024.pdf}, author = {Danielle Duni and Jeffrey E. Herrick and D.A. Pyke and David P. Toledo} } @article {50043, title = {Acquisition, orthorectification, and classification of unmanned aerial vehicle (UAV) imagery for rangeland monitoring}, journal = {Photogrammetric Engineering and Remote Sensing}, volume = {76}, number = {6}, year = {2010}, pages = {661-672}, abstract = {The use of unmanned aerial vehicles (UAVs) for natural resource applications has increased considerably in recent years due to their greater availability, the miniaturization of sensors, and the ability to deploy a UAV relatively quickly and repeatedly at low altitudes. We examine in this paper the potential of using a small UAV for rangeland inventory, assessment and monitoring. Imagery with a ground resolved distance of 8 cm was acquired over a 290 ha site in southwestern Idaho. We developed a semiautomated orthorectification procedure suitable for handling large numbers of small-footprint UAV images. The geometric accuracy of the orthorectified image mosaics ranged from 1.5 m to 2 m. We used object-based hierarchical image analysis to classify imagery of plots measured concurrently on the ground using standard rangeland monitoring procedures. Correlations between imageand ground-based estimates of percent cover resulted in r-squared values ranging from 0.86 to 0.98. Time estimates indicated a greater efficiency for the image-based method compared to ground measurements. The overall classification accuracies for the two image mosaics were 83 percent and 88 percent. Even under the current limitations of operating a UAV in the National Airspace, the results of this study show that UAVs can be used successfully to obtain imagery for rangeland monitoring, and that the remote sensing approach can either complement or replace some ground-based measurements. We discuss details of the UAV mission, image processing and analysis, and accuracy assessment.}, keywords = {assessment, journal, monitoring, orthorectifiction, rangeland inventory, UAV, unmanned aerial vehicle}, url = {/files/bibliography/10-08.pdf}, author = {Andrea S. Laliberte and Jeffrey E. Herrick and A. Rango} } @conference {JRN54486, title = {Arid soil microbial enzymatic activity profile as affected by geographical location and soil degradation status}, booktitle = {13th International Symposium on Microbial Ecology}, year = {2010}, month = {08/2010}, publisher = {Microbial Ecology International Symposium}, organization = {Microbial Ecology International Symposium}, address = {Seattle, WA}, abstract = {Evaluating soil health is critical for any successful remediation effort. Arid lands, with their minimal carbon and water contents, low nutritional status and restricted, seasonal microbial activity pose specific challenges to soil health restoration and by extension, restoration of ecosystem representative plant populations. Thus it is hypothesized that microbial metabolic profiles in arid soil are sensitive to relatively minor climatic variations and also to changes in soil physico-chemical parameters induced by human activities. We evaluated the total-soil enzymatic activity profiles for two distinct arid zone locations, one in the Northern Chihuahuan (NC) desert and a second one on tablelands in the Arizona/New Mexico Plateau (ANMP). At the latter site we targeted undisturbed areas as well as heavy metal contaminated lands remediated following surface coal mining. Enzymatic activity profiles were estimated by carbon substrate utilization via total soil respiration assays using the MicroResp{\textregistered} system. Results indicate that in general the NC samples exhibited more complex enzymatic activity profiles than the non-disturbed ANMP samples. Comparison of rhizosphere and non-rhizosphere soils indicated that the divergence in the enzymatic activity profiles was more obvious for the remediated areas than for the native non-disturbed areas. This suggests that the gradients in enzymatic activity profiles from rhizosphere to non-rhizosphere samples may be possibly used to assess the rate and status of remediation of such lands. Thus, for arid lands, the enzymatic activity profiling may be used to evaluate 1) the significance of local climatic and edaphic conditions on the metabolic range of the soil microbial activity and 2) the health status of degraded or remediated arid region soils.}, author = {Tahtamouni, Mohammad E. and Unc, Adrian and M.E. Lucero and Sa{\textquoteright}eb Khresat} } @conference {JRN54153, title = {Adapting livestock behaviour to achieve management goals}, booktitle = {Saskatchewan Ministry of Agriculture }, year = {2009}, month = {06/2009}, address = {Moose Jaw, Saskatchewan}, abstract = {

Using livestock to efficiently achieve management goals requires melding animal behavior with mechanical and electronic equipment.\  Practices such as autonomously obtaining individual animal liveweight when combined with individual animal electronic identification can produce numerous cost saving advantages by bringing together cause and effect events in a meaningful time frame that allows for proactive management intervention.\  Other technologies such as fluorometry makes it possible to rapidly determine what free-ranging animals are eating including those plants that may be toxic to an animal\&$\#$39;s health.\  Soon virtual fencing will be commercially available making the spatial and temporal control of animals in real time a reality. All of these evolving technologies when used appropriately will foster low stress animal handling, the keystone in realizing optimum free-ranging animal management goals.

}, author = {D.M. Anderson} } @conference {JRN54154, title = {The art in getting flocks and herds to flerds}, booktitle = {Symposium Series. Multi-Species Grazing}, year = {2009}, month = {06/2009}, address = {Moose Jaw, Saskatchewan}, abstract = {

Flerds (small ruminants that consistently stay near cattle under free-ranging conditions) offer four distinct advantages over stocking simply flocks and herds to carry out mixed species stocking.\  One of the main advantages flerds offer is added protection from canine predation, reduced time in locating mixed-species groups, the control of small ruminants without conventional net wire fencing and the ability to foster uniform stocking pressure over the landscape during foraging.\  Though flerds are created by socializing large and small ruminants through a continuous close association either in pens or in the field, there are distinct practices to insure cohesive and enduring flerds including preventing physical abusiveness directed to the small ruminants from cattle.\ \  The art and science associated with realizing successful bonding that results in enduring flerds requires observing and immediately altering animal behaviors and management practices that would prevent or alter interspecific bonds from developing.

}, author = {D.M. Anderson} } @article {50084, title = {Accelerate synthesis in ecology and environmental sciences}, journal = {BioScience}, volume = {59}, number = {8}, year = {2009}, month = {09/2009}, pages = {699-701}, chapter = {699}, abstract = {

Ecology is a leading discipline in the synthesis of diverse knowledge. Ecologists have had considerable experience in bringing together diverse, multinational data sets, disciplines, and cultural perspectives to address a wide range of issues in basic and applied science. Now is the time to build on this foundation and invest in ecological synthesis through new national or international programs. While synthesis takes place through many mechanisms, including individual efforts, working groups, and research networks, centers are extraordinarily effective institutional settings for advancing synthesis projects.

}, keywords = {analytical, ecology, snythetic, synthesis, visualization}, doi = {10.1525/bio.2009.59.8.11}, url = {/files/bibliography/09-022.pdf}, author = {S. R. Carpenter and Armbrust, E.V. and Arzberger, P. and F.S. Chapin III and Elser, J. and Hackett, E. and Ives, A. and Kareiva, P. and Leibold, M. and Lundberg, P. and Mangel, M. and Merchant, N. and Murdoch, W.W. and Palmer, M.A. and Debra C. Peters and Steward T.A. Pickett and Smith, K.K. and D.H. Wall and Zimmerman, A.S.} } @article {50094, title = {Animal disturbances promote shrub maintenance in a desertified grassland}, journal = {Journal of Ecology}, volume = {97}, year = {2009}, note = {//NMSU,USDA//LTER V//entered 10/14/2009; pdf available}, month = {2009}, pages = {1302-1310}, chapter = {1302}, abstract = {

Soil disturbance by animals affects the availability of water, nutrients, sediment and seeds, which are critical for the maintenance of functional ecosystems. We examined long-lived faunal structures across six vegetation communities in the northern Chihuahuan desert of New Mexico, USA, testing the proposition that disturbances in undesertified grassland differ in magnitude and effect from those in desertified grassland.\  Vertebrate and invertebrate disturbances totalled 18.9 structures ha)1 across 18 sites. The most common were pits and mounds of American badgers (Taxidea taxus, 32\%), nests of the ant Aphaenogaster cockerelli (18.8\%) and mounds of kangaroo rats (Dipodomys spectabilis, 31\%).\  Desertification was associated with a doubling of the density of structures, but no effects on cover or volume. The greatest density was in desertified mesquite and creosote bush shrublands, and the lowest density in undesertified grass swales. Badger and wood rat (Neotoma sp.) mounds were significant indicators of desertified communities. Desertification did not affect the density of kangaroo rat mounds (6.7 ha)1 in black grama grasslands and creosote bush shrublands). However, mounds in creosote bush shrubland were smaller and had more and larger shrubs than adjacent inter-mound hummocks. Desertification was associated with increases in the density of Aphaenogaster cockerelli and Trachymyrmex smithii nests, and declines in Pogonomyrmex rugosus nests. Substantial increases in soil nitrate and electrical conductivity on Myrmecocystus nests were associated with desertification. Synthesis. Desertification shaped this desert environment in two main ways. First, while kangaroo rat mound density changed little with desertification, mounds in shrubland continued to enhance shrub persistence long after abandonment, reinforcing desertification processes. Second, marked changes in the density of nests of the key ant species altered the spatial distribution of soil nitrate and electrical conductivity, likely affecting soil fertility and the distribution of desert plants. Our results highlight the importance of animal activity in shaping desert plant communities, and in maintaining or reinforcing desertification processes.

}, keywords = {animal activity, article, Biopedturbation, Chihuahuan Desert, desertification, disturbance, ecosystem engineering, journal, pedogenesis}, doi = {10.1111/j.1365-2745.2009.01558.x}, url = {/files/bibliography/10-036.pdf}, author = {D.J. Eldridge and Walter G. Whitford and B.D. Duval} } @conference {50120, title = {Adapting ecological sites descriptions to enhance wildlife management: Lessons learned from the 2007 society for range management workshop}, booktitle = {62nd Society or Range Management Annual Meeting}, year = {2009}, month = {02/2009}, pages = {1000-18}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Alb., NM}, abstract = {

The Society for Range Management in cooperation with federal, state, and private partners sponsored a workshop in Park City, Utah in October 2007 to better introduce range and wildlife management professionals Ecological Site Descriptions (ESDs). The workshop was attended by over 300 land and wildlife/habitat managers, biologists, range ecologists, soil scientists, technical assistance professionals, local sage-grouse working group members, consultants, and petroleum industry representatives from throughout western North America. During the workshop, participants were broken into facilitated working groups to examine draft ESDs (including both state and transition model components and interpretations) for application to managing sagebrush steppe ecosystems for sage-grouse (Centrocercus spp.) and other sagebrush-obligate wildlife. Each group was tasked to identify strengths and weaknesses of the models and provide suggestions for the testing and enhancement of the tool for sagebrush ecosystem management. The groups also identified information gaps, defined priorities for research, and explored processes to incorporate the best science into the models. Some general themes that emerged from the working groups included; 1) the need for ESDs to incorporate increased flexibility in vegetation descriptions particularly as they relate to wildlife cover, 2) better integration of ecological functionality with wildlife habitat quality, and 3) expanded discussions of habitat values for both game and nongame species. Lastly, the participants expressed strong support for expanding the process of constructing ESDs to solicit input and involvement from wider audiences. In the interim, NRCS biologists and rangeland management specialists are closely examining fish and wildlife life history requirement to determine additional metrics needed for integration into the ESD template. In this poster we expand on these and other areas of suggested improvements.

}, keywords = {ecological site descriptions, ESD, ESDs, SRM}, author = {J. Maestas and T.A. Messmer and Joel R. Brown} } @inbook {50129, title = {Approaches to predicting broad-scale regime shifts using changing pattern-process relationships across scales}, booktitle = {Real World Ecology: Large-scale and long-term case studies and methods}, year = {2009}, month = {2009}, pages = {47-72}, address = {New York}, abstract = {

Understanding and predicting the occurrence of alternative ecosystem states (i.e., regime shifts) at broad scales is a pressing challenge for ecologists given the scope and nature of global change. In many cases, regime shifts at broad-scales are affected by pattern-process relationships across a range of finer scales. However, experimental and analytical methods to examine state changes, such as from perennial grasslands to woodlands, have not been fully developed. We first define and describe the expansion of woody plants into perennial grasslands. Woody plant encroachment has well-documented consequences for local, regional, and global ecology, and takes several forms, from shrub invasion in arid/semiarid grasslands and arctic ecosystems to tree invasion in mesic and alpine grasslands. We then outline a multi-scale experimental approach to examining the key processes influencing woody plant encroachment from fine to broad scales, and describe the application of this approach to the Jornada Basin Agricultural Research Service-Long Term Ecological Research site as a case study. Several questions can be addressed with this approach, such as: how and under what conditions do dynamics and decisions made at fine scales influence dynamics at broader scales? How and under what conditions do broad-scale dynamics overwhelm fine-scale processes to influence landscape patterns? Finally, we discuss analytical techniques for predicting regime shifts and their associated thresholds.

}, keywords = {broad-scale regime, pattern-process}, doi = {10.1007/978-0-387-77942-3_3}, url = {files/bibliography/JRN00523.pdf}, author = {Debra C. Peters and Brandon T Bestelmeyer and A. K. Knapp and Jeffrey E. Herrick and Curtis H. Monger and Kris Havstad} } @conference {JRN54476, title = {An analysis of MODIS fractional snow cover estimates for snowmelt runoff modeling.}, booktitle = {American Geophysical Union}, year = {2009}, month = {12/2009}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {San Francisco, CA}, abstract = {

Rio Grande streamflow is fed primarily by water from the melting snowpack in mountainous basins in the Southern Rockies. The snowpack accumulates mass in winter months and melts continuously through Spring and Summer. It is estimated that snowpack contributes 50\% of the annual water supply of Colorado and New Mexico. A warmer winter climate anomaly, earlier snowmelt and declining snowpack in mountainous basins has been observed since the 1950s throughout the Western United States. The effect of this warming climate pattern on snowpack mass, extent and duration has serious implications for water resources in the entire Rio Grande basin.

We use the Snowmelt Runoff Model (SRM: Martinec et al., 2008) to provide seasonal estimates of runoff contributions from snow cover in the upper Rio Grande basin and to predict runoff under different future climate scenarios. Sub-basin snow cover at a range of dates through the melt season is a key input variable driving SRM. Remotely sensed estimates of fractional snow cover, such as the MODIS snow cover product (MOD10A1 and MYD10A1, are the most available sources of snow cover but the accuracy of these estimates is highly variable. The aim of our current research is to compare existing snow cover products against alternative methods for estimating sub-pixel snow cover. Because we intend to share our snow mapping method with local water resource managers, we also aim to identify the most accurate, least complex algorithm to use for estimating snow cover from remotely sensed data.

In this paper we compare four methods for estimating fractional snow cover from 500 m MODIS data: (i) the empirical model of Kaufman et al., (2002) (ii) linear mixture modeling (Andersen, 1982), (iii) the Normalized Difference Snow Index (NDSI; Salomonson and Appel, 2002) calculated from MODIS daily reflectance products (MOD09GA and MYD09GA) and (iv) the MODIS daily fractional snow product (Salomonson and Appel, 2002) available from the National Snow and Ice Data Center. To evaluate accuracy of each method, all snow cover estimates from MODIS data were compared with snow cover estimates derived from 30 m Landsat TM data for a range of dates and snow conditions between 2001 and 2008. We also compare the results for both the Aqua and Terra sensors. Further, to ascertain the degree of error that could be introduced into snowmelt runoff predictions by each mapping method, we run SRM for the snowmelt season of 2009.

}, author = {Caitriana Steele and A. Rango and M. Bleiweiss} } @conference {50155, title = {Assessment of the landscape aspects of conservation practices}, booktitle = {62nd Society for Range Management Annual Meeting}, year = {2009}, month = {February 8, 2009}, pages = {11-9}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Alb., NM}, abstract = {We review how landscape structure and processes have been considered in the design and assessment of conservation practices. We show how landscape concepts are essential to the success of rangeland conservation practices via theoretical considerations and empirical examples. The core concepts of scale, spatial heterogeneity and pattern are explored along with a set of case studies. A two-fold literature review is carried out. The first considers peer-reviewed literature examining applications of landscape concepts in conservation practices and their impacts. The second uses agency documents describing conservation practices and their policy outcomes at state and national levels. Critical knowledge gaps are identified and the mismatches between research and assessment needs are highlighted. Recommendations for the regional-scale landscape planning process and support tools building upon existing agency technology support systems are developed, as well as guidelines for consideration of landscape processes in field-scale applications. Needs and priorities for monitoring and research are identified to build better linkages between research and conservation practices and assessment.}, keywords = {abstract, conservation practicies, landscape desing, spatial heterogeneity, SRM}, author = {Wu, B.X. and Brandon T Bestelmeyer and Joel R. Brown and S. Fuhlendorf} } @conference {JRN54152, title = {Analysis of complex samples using a portable multi-wavelength light emitting diode (LED) fluorescence spectrometer}, booktitle = {Federation of Analytical Chemistry and Spectroscopy Societies }, year = {2008}, month = {09/2008}, address = {Reno, Nevada}, abstract = {

Spectroscopic analysis of chemically complex samples often requires an increase n the dimensionality of the measured response surface. This often involves the measurement of emitted light intensities as functions of both wavelengths of excitation and emission resulting in the generation of an excitation-emission matrix (EEM) for each sample. Unfortunately, the complexity of instrumentation for selective illumination of samples with narrow wavelength band-widths of excitation radiation typically limits the application of such measurements from the analysis of in-field samples. This has recently been addressed by the use of a collection of light emitting diodes (LEDs) as excitation sources with varied wavelengths for the generation of EEMs. Although these sources emit relatively broad wavelength bands, analysis of the resulting multi-dimensi0ona spectral signatures using multivariate techniques (e.g., PCA and PARAFAC) enables the direct analysis of complex samples. Application of this technique to agriculturally important samples will be described and the implication of these results for in-field determinations will be discussed.

}, author = {B. Bai and D.M. Anderson and G.D. Rayson} } @conference {50169, title = {Assimilation of AATSR, MERIS and MODIS data in the snowmelt runoff model (SRM) on the upper Rio Grande (USA)}, booktitle = {AGU 2008 Fall Meeting}, year = {2008}, month = {12/2008}, pages = {C21C-0576}, address = {San Francisco, CA}, abstract = {

Current efforts for simulating or forecasting snowmelt are time-consuming and laborious; the AWARE project (A tool for monitoring and forecasting Available WAter REsource in mountain environments) has been motivated by the urgent need to facilitate the prediction of medium-term flows from snowmelt for an effective and sustainable water resources management. Its main goal is to provide innovative tools for monitoring and predicting water availability and distribution in drainage basins where snowmelt is a major component of the annual water balance. The particular objective of the effort reported here is to compare results obtained from the MODIS sensor on NASA Terra and Aqua satellite and next generation sensors AATSR and MERIS on board ESA Envisat satellite. The vehicle for this comparison is the AWARE Geoportal (http://www.aware-eu.info/eng/home.htm) which is a WWW implementation of the Snowmelt Runoff Model (SRM). The river basin chosen for analysis is the Upper Rio Grande of North America. The time period for analysis encompasses the Water Years 2005, 2006, and 2007 (October 2004 September 2007). The reason for this is to ensure that data from all three sensors are available for use and to investigate variable climate conditions. A successful comparison between the various sensors will help demonstrate that the AWARE approach will facilitate future processing of several years\&$\#$39; worth of snow cover data from a variety of sensors that covers large extremes in climate variability. This will allow greater success in developing forecasts and understanding of longer term climate change impacts.

}, keywords = {AATSR, AWARE, MERIS, MODIS, snowmelt}, author = {M. Bleiweiss and Rampini, A. and Pepe, M. and A. Rango and Caitriana Steele and Stein, W. and T. J. Schmugge} } @conference {50201, title = {Assessing resilience of western rangelands to transportation-related land-use change}, booktitle = {Geological Society of America}, series = {2008 Joint Meetings}, year = {2008}, month = {10/2008}, pages = {51-10}, address = {Houston, TX}, abstract = {

The amount and extent of transportation related activity in western rangelands has rapidly increased in recent decades. This increase is due to a variety of factors including oil and gas development, recreational activities, and ex-urban development. In addition to areas directly impacted by infrastructure installation, the presence and use of these travelways has potentially altered the resilience of adjoining areas through indirect effects such as altered site hydrologic and eolian processes, invasive seed dispersal, and sediment transport. Direct and indirect impacts of these networks are of particular concern in ecosystems with inherently low resilience, such as those with aridic soils. There is little guidance, however, on appropriate methods for assessing and monitoring the impacts of transportation related land-use activities on soils and vegetation. We tested the sensitivity of a qualitative assessment technique (Interpreting Indicators of Rangeland Health) and quantitative measures to roads, trails, and pipelines. The protocols used have a demonstrated connection to soil nutrient and moisture-related processes in a wide range of ecosystems. We conducted surveys at plots near, far and very far from travelways at 16 sites selected using a stratified random sampling design in 3 ecosystems for a total of 208 plots evaluated. Results indicate that qualitative techniques are sensitive to direct and indirect impacts of transportation activities. Additionally, differences detected with qualitative techniques between areas near, far and very far from disturbances followed the same trends and were highly correlated with quantitative measures. The qualitative and quantitative assessment techniques employed in this study can be used to assess impacts of individual transportation features or to assess cumulative impacts of a transportation network. Assessing how transportation related activities on western rangelands affects ecosystem resilience is crucial for understanding how these systems will respond to the warmer and drier conditions predicted as a result of global climate change.

}, keywords = {decades, ex-urban, transportation activity}, author = {Danielle Duni and Jeffrey E. Herrick} } @conference {50225, title = {Application of soil physical models to predict soil deposition effects on plant establishment}, booktitle = {93rd Ecological Society of America Annual Meeting}, series = {93rd ESA Annual Meetings}, year = {2008}, month = {August 4-8, 2008}, pages = {48-147}, address = {Milwaukee, WI}, abstract = {Soil erosion and deposition often result in significant soil profile modifications, including soil surface texture and structure changes. These properties affect water infiltration and available water holding capacity, both of which affect plant water availability. Because plants are especially sensitive to desiccation during establishment, near-surface changes in these properties can have significant effects on plant community dynamics. The objective of this study was to quantify the effects of soil erosion and deposition on plant establishment, and to explore the patterns of shrub encroachment associated with soil deposition. A field study and a series of modeling exercises were completed at the Jornada Experimental Range in association with the Jornada LTER. The Jornada is located in the northern Chihuahuan Desert in south-central New Mexico, and receives approximately 245mm of precipitation, the majority of which arrives during the summer growing season. The field study included repeat air photo analysis, detailed mapping of plant cover, composition and spatial structure, field soil interpretation, and characterization of contemporary soil redistribution based on cesium analyses.}, keywords = {abstract, despsition, soil erosion, water infiltration}, author = {Jeffrey E. Herrick and Debra C. Peters and N.K. Hansen and Jerry Ritchie and Curtis H. Monger and Gregory S. Okin} } @conference {50234, title = {Addressing challenges in cross-site synthesis of long-term ecological data}, booktitle = {Ecological Informatics International Conference}, series = {International Conference on Ecological Informatics 6}, year = {2008}, month = {12/2008}, address = {Cancun, Mexico}, abstract = {Long-term ecological datasets are becoming increasingly abundant on the internet, and are available both on websites hosted by the originating sites and/or in online repositories. While sites and networks are increasingly conforming to adopted metadata standards (which themselves continue to evolve to meet modern data collection challenges), the data themselves are often found in seemingly infinite combinations of 1) various formats, ranging from fixed width format to complex Microsoft Excel workbooks, 2) various levels of quality, from raw, unchecked data to flagged and corrected data values, and 3) various levels of time-step aggregations, from the raw data that include every data point measured, to data aggregated into annual means, totals or other estimations. In addition, datasets are documented to varying levels of completeness. Thus, the time-consuming process of preparing data from different sites (or even from different studies) for synthetic analyses and visualization often falls on the researchers interested in making the comparisons, with support of principal investigators and information managers associated with the project or site of origination. Over time, many researchers may have to independently aggregate the same data. With increasing demand for these synthetic analyses, coupled with decreasing availability of time and funding, it is important that these datasets be made not only more accessible, but in forms that allow comparisons and visualizations to be made quickly and in a single website location. To respond to this demand, the EcoTrends project (http://www.ecotrends.info) was initiated in 2004 to synthesize long-term datasets (> 10 years) from many US sites. Here, we discuss how data were obtained from partnering sites; how they were handled, from origination to derivation being made available on the EcoTrends web portal; and how the website component of this project meets the needs of ecologists. We also discuss lessons learned along the way and present recommendations for future projects.}, keywords = {ecological, EcoTrends, informatics, long-term}, author = {C. Laney and Servilla, M. and Debra C. Peters} } @conference {50252, title = {Assessing the importance of landscape attributes for livestock distribution within a complex desert environment}, booktitle = {Ecological Society of America Abstracts}, year = {2008}, month = {August 4-8, 2008}, pages = {54-22}, address = {Milwaukee, WI}, abstract = {Predictive models of grazing distribution are used to explore livestock {\textendash} landscape interactions. However, conventional models based on local foraging rules or regression analyses have limited predictive value at larger scales commonly of interest to land managers. We developed a landscape scale model that matches the spatial scale of decision factors with the predicted distribution pattern. The model was used to infer how animals integrate landscape factors. Predictive models of grazing suitability were generated for different seasons (Spring and Fall) and cattle breeds (Angus and Criollo) in a 2,425 ha pasture on the Jornada Experimental Range located in the northern Chihuahuan Desert. Models generate raster maps of grazing suitability using an adapted version of the Multi-Criteria Evaluation method from decision theory. Four factors: vegetation, distance from water, shrub density, and elevation were represented by 10 m grid maps. Independent GPS collars grazing positions data acquired at 5-minute intervals were used to calculate decision functions, which describe animal preference for different landscape attributes, and to evaluate how well the model fit the data. Models with three predictors produced the best fit of the data. Distance to water was the most important factor in all models. Animals showed higher preferences for areas within 4 to 6 km of permanent water depend upon breeds. Other factors were included with lower relative importance. Animal preferences were greater for areas with low shrub density and for low elevation sites where Pleuraphis mutica, Schleropogon brevifolius, and Sporobulus spp. dominate heavier texture soils. Suitable areas delimited by the models realistically represent the observed spatial pattern of grazing. Between 70 to 90 \% of grazing positions occurred in cells classified by the model as suitable. Conversely, the number of suitable cells was 5 to 8 times larger than the observed grazed cells. These differences may have occurred because grazing positions correspond to a very low stocking rate (6 cows in a 2,425 ha pasture); under a realistic situation the number of grazed cells is expected to largely increase. According to the models the pasture is characterized by a single or few large grazing patches which includes about 80\% of all suitable cells for grazing. This modeling approach can contribute to an understanding of how large animals perceive landscape heterogeneity.}, keywords = {abstrace, landscape, landscape attributes, livestock}, author = {H. Raul Peinetti and E.L. Fredrickson and Debra C. Peters and Roacho-Estrada, J.O. and Andrea S. Laliberte} } @proceedings {50296, title = {Age at puberty in beef heifers: Criollo cattle versus British crossbred cattle}, volume = {59}, year = {2008}, month = {June 24-26, 2008}, pages = {237-240}, address = {Laramie, WY}, abstract = {

Age at puberty is an important factor in estimating the potential productivity of the bovine female. A study was conducted at the ARS-USDA Jornada Experimental Range in 2006 and 2007 to compare onset of puberty, BW, and serum insulin in Criollo and Angus-Hereford crossbred heifers. In 2006, 7 Criollo and 5 crossbred heifers were used to determine length of the estrous cycle and insulin concentrations. Heifers grazed the same pasture during the study with free access to water and mineral supplement. Blood samples were collected twice weekly for both years. In 2007, 15 Criollo and 15 crossbred heifers were used to determine age to puberty (2 or more consecutive progesterone concentrations \> 1 ng/mL), length of the estrous cycle, and insulin concentrations. Initial BW in both 2006 and 2007 crossbred heifers were heavier (P \< 0.01), when compared to Criollo heifers (251.7 and 166.4 \± 12.9 kg; 236.2 and 158.8 \± 4.7 kg, respectively). In 2006, BW gain did not differ (P \< 0.01) between breeds (80.5 and 71.1 \± 4.4 kg for crossbred and Criollo heifers, respectively). In 2007, crossbred heifers gained more BW than Criollo heifers during the study (P \< 0.01; 128.2 and 91.2 \± 4.1 kg, respectively). In 2007, BW at puberty (P \< 0.01) was greater for crossbred heifers than Criollo heifers (323.8 and 213.9 \± 6.6 kg, respectively). However, Criollo heifers tended (P = 0.15) to reach puberty earlier than crossbred heifers (363.5 and 376.7 \± 6.3 d, respectively). Estrous cycle length between crossbred and Criollo heifers in both 2006 and 2007 did not differ (P \> 0.53; 18 and 19 \± 1 d; 18 and 19 \± 1 d, respectively). Serum insulin concentrations were also greater (P \< 0.01), for Criollo compared to crossbred heifers in both 2006 and 2007 (0.67 and 0.54 \± 0.02 ng/mL; 0.68 and 0.58 \± 0.02 ng/mL, respectively). This study suggests that Criollo heifers may reach puberty earlier than British breeds.

}, keywords = {age, Angus-hereford, bovine, Criollo, female, proceedings, productivity}, url = {/files/bibliography/08-058.pdf}, author = {Valverde-Saenz, S.I. and Walsh, J.D. and Gardner, C.M. and Mulliniks, J.T. and Schilling, B.S. and Hallford, D.M. and A L Conzalez and E.L. Fredrickson and Kane, K.K. and Hawkins, D.E.} } @conference {50353, title = {Approaches for mapping and monitoring arid rangelands with object-based image analysis and hyperspatial imagery}, booktitle = {2nd Annual Symposium on Object-Based Image Analysis}, year = {2007}, month = {June 7-8, 2007}, address = {Berkeley, CA}, abstract = {At the USDA Agricultural Research Service Jornada Experimental Range (JER) in southern New Mexico, remote sensing research is focused on finding new methods for mapping and monitoring rangelands, and on relating ground-based surveys to remotely sensed information. This presentation will give an overview or recent research at JER involving object-based image analysis and hyperspatial imagery ranging from QuickBird satellite imagery, aerial photography, imagery acquired with unmanned aircraft, to ground-based plot photography. The QuickBird image was segmented at multiple scales to map shrubs at a fine scale and other vegetation communities at coarser scales. We were able to identify and map 87\% of shrubs greater than 2 m2. A decision tree was used as an effective tool for sorting through the numerous input features and reducing them to a manageable rule set for classification. The overall accuracy was 80\% for the optimal segmentation scale. In this case, we used ground-based plot photography as ground truth for the QuickBird remote sensing analysis. We compared image-based estimates of vegetation cover with line-point-intercept (LPI) measures for 50 plots (2.5 m x 3.5 m). The images were transformed from the RGB (red, green, blue) to the IHS (intensity, hue, saturation) color space. Object-based image analysis was used to classify the images into soil, shadow, green vegetation, and senescent vegetation using a masking approach and combination of membership rules and nearest neighbor classification. The correlation coefficients between LPI- and image-based estimates for the four classes ranged from 0.88 to 0.95. The object-based image approach was less labor and time intensive than the LPI method and has the potential to be incorporated into rangeland monitoring protocols. Our latest tool for rangeland monitoring is an unmanned aerial vehicle (UAV), capable of acquiring 5 cm resolution imagery from a 150 m above ground flying height. While the imagery presents some challenges for orthorectification and mosaicking, object-based image analysis has already proven to be highly successful. The very high-resolution imagery allows for identification of individual plants, patches, gaps, and patterns not previously possible, and will allow for assessment of rangeland health and ecosystem change at multiple scales. While this is a project in progress, initial mapping results indicate accuracies in the high 90\% range. Based on this recent research, it is apparent that object-based image analysis will play a major part in future rangeland mapping and monitoring at multiple scales. It is also apparent that new tools in object-based image analysis will be needed, specifically in the area of object-based accuracy assessment.}, keywords = {analysis, image, mapping, object-basaed}, author = {Andrea S. Laliberte and A. Rango} } @conference {50362, title = {Adapting the rangeland database for managing ecological site description data}, booktitle = {Society for Range Management Annual Meeting}, year = {2007}, month = {02/09/2007}, pages = {Paper No. 286}, address = {Reno/Sparks, NV}, abstract = {Field data collection for writing Ecological Data Descriptions (ESD) creates a paperwork burden that reduces efficiency of ESD preparation. The recently developed Rangeland Database and Field Data Entry System is well suited to managing ESD data. This database was developed to automate data entry and analysis for protocols in \– Monitoring Manual for Grassland, Shrubland, and Savanna Ecosystems. After collecting 2005 data on paper and entering into Ecological Site Information System, Synergy Resource Solutions, Inc., looked for a more efficient solution to data management. Scientists at Jornada Experimental Range released the Rangeland Database before the 2006 field season. Synergy used the new database to collect and analyze ESD (and other data) Collaboration between field personnel and database developers resulted in several adaptations to increase utility of the database for ESD purposes. Field application has shown that the database saves data entry time without sacrificing in-the-field efficiency, reduces data entry errors, provides for real time analysis, provokes real time field discussion of ecological theory, and reduces the time lag (and motivational challenge) associated with data entry months after fieldwork is complete. The ease of use and adaptation of the Rangeland Database allow for project-specific customization. Adaptation of project tracking and progress reporting increased efficiency of our current project.}, keywords = {Ecological Data Descriptions, ESD}, author = {Meccage, R. and J. Alexander and Ericha Courtright and Jeffrey E. Herrick and Brandon T Bestelmeyer and Kluck, J.} } @article {50365, title = {Application of multi-way data analysis on excitation-emission spectra for plant identification}, journal = {Talanta}, volume = {72}, year = {2007}, month = {April 1, 2007}, pages = {682-690}, abstract = {The ability to distinguish among diets fed to Damascus goats using excitation-emission luminescence spectra was investigated. These diets consisted of Medicago sativa L. (Alfalfa), Trifolium spp (Clover), Pistacia lentiscus (P.lentiscus), Phyllirea latifolia (P.latifolia), and Pinus brutia (P. brutia). The three dimensional luminescence response surface from phosphate buffered saline extracts of each material was analyzed using muti-way analysis chemometric tools (MPCA) and parallel factor analysis (PARAFAC). Using three principle components, the spectra from each diet component was distinguished. Additionally, fecal samples from goats fed diets of either alfalfa or clover hays were investigated. The application of MPCA and PARAFAC to these samples using models derived from the pre-digested diet materials was strongly suggestive of the utility of similarly derive training samples for the elucidation of botanical diet composition for animals.}, keywords = {luminescence spectroscopy, multi-way principal component analysis (MPCA), parallell factor analysis (PARAFAC), phosphate buffered saline plant extracts}, url = {/files/bibliography/07-007.pdf}, author = {S. Obeidat and G.D. Rayson and D.M. Anderson and Landau, S.Y. and Glasser, T.} } @conference {50422, title = {Animal Control-What constitutes a reliable cue to stop animal movement?}, booktitle = {Society for Range Management 59th Annual Meeting}, year = {2006}, month = {February 12-17, }, address = {Vancouver, British Columbia}, abstract = {Controlling free-ranging livestock requires low-stress cues to alter animal behaviour. Recently modulated sound and electric shock were demonstrated to be effective in controlling free-ranging cattle. In this study the behaviour of 60, 300 kg Belmont Red heifers were observed for behavioural changes when presented cues designed to impede their movement through an alley. The heifers were given an overnight drylot shrink off feed but not drinking water prior to being tested. Individual cattle were allowed to move down a 6.5 m wide alley towards a pen of peers and feed located 71 m from their point of release. Each animal was allowed to move through the alley unimpeded five times to establish a basal behavioural pattern. Animals were then randomly assigned to treatments consisting of sound plus shock, vibration plus shock, a visual cue plus shock, shock by itself and a control. The time each animal required to reach the pen of peers and feed was recorded. If the animal was prevented from reaching the pen of peers and feed by not penetrating through the {\textquoteright}cue barrior{\textquoteright} at set points along the alley for at least 60 sec the test was stopped and the animal was returned to peers located behind the release pen. Cues and shock were manually applied from a laptop while animals were observed from a 3.5 m tower located outside the alley. Electric shock, sound, vibration and Global Position System (GPS) hardware were housed in a neck collar. Results and implications will be discussed.}, keywords = {animal control, animal movement, free-range, virtual fencing}, author = {Bishop-Hurley, G.J. and Swain, D.L. and D.M. Anderson and Peter Corke} } @conference {50438, title = {Antiherbivory Compounds on the Leaf Surface of Intact and Resprouted Tarbush}, booktitle = {2006 Joint Annual Meeting, American Society of Animal Science, American Dairy Science Association}, volume = {J. Animal Sci. Vol. 84, J. Dairy Sci. Vol. 89}, number = {1}, year = {2006}, month = {July 9-13, 2006}, pages = {22}, address = {Minneapolis, Minnesota}, abstract = {Shrub encroachment into desert grasslands of the southwestern United States is a serious problem, resulting in loss of forage and rangeland productivity. Flourensia cernua (tarbush) is one such shrub contributing to the decline of Chihuahuan Desert grasslands. Our previous research has shown tarbush consumption by sheep and goats to be negatively related to leaf surface concentration of individual terpenes and epicuticular wax. Concentrations of antiherbivory compounds such as terpenes change with plant age and phenology. Our objective was to alter the vegetative state and potential palatability of tarbush by clipping intact plants and generating resprouts. We hypothesized resprouts would invest fewer resources into antiherbivory compounds and therefore have lower concentrations of volatile chemicals such as terpenes than intact plants. Ninety tarbush plants were randomly selected, and all biomass within 10 cm of the soil surface was removed from 45 plants during winter dormancy. Leaves were collected the following summer during active growth from the canopy of intact controls and resprouts. Leaf surface volatiles were extracted in ethanol and analyzed by gas chromatography-mass spectroscopy to determine their identity and concentration. Data were transformed to natural logarithms and subjected to univariate analysis of variance and stepwise discriminate analysis. Of the 87 compounds present on tarbush leaves, 35 were greater in canopy samples and 16 were greater in regrowth samples based on univariate analysis (P < 0.05). Mean concentration of total volatiles on canopy leaves tended to be less (P = 0.0622) than that of regrowth (3642 vs 4684 {\textquoteright}g/g DM). Nine compounds in the discriminate analysis explained 95\% of the variation between canopy and regrowth samples. In contrast to our hypothesis, lower cumulative concentration of volatile compounds in canopy than regrowth samples suggests repsrouts may be less vulnerable to herbivory than old growth tarbush. However, animal studies are needed and effects on other classes of secondary compounds must be examined.}, keywords = {regrowth, shrub, terpene}, author = {Richard E. Estell and E.L. Fredrickson and M.D. Remmenga} } @conference {50458, title = {An agenda for ecology in an era of globalization}, booktitle = {Ecological Society of America Abstracts}, number = {Paper No. 60558}, year = {2006}, month = {August 8, 2006}, address = {Memphis, TN}, abstract = {The relationship between ecological sustainability and human poverty is evolving rapidly in response to changes associated with the globalization of capital, labor, natural resources and knowledge. The processes associated with globalization lead to changes in the scale, patterns and relationships between poverty and environmental degradation. Due to the increased mobility of labor and capital, environmental degradation and opportunities for restoration increasingly appear in areas with relatively little social, environmental and scientific infrastructure, while most ecological investigations remain focused on a limited number of study sites concentrated in the countries of highly developed western economies. At the same time, the increasing globalization of knowledge provides new opportunities for environmental scientists to address these challenges. We propose an agenda for ecology in an era of globalization that includes three changes in the way ecologists work: (1) an increased willingness and ability to rapidly change the focus and the spatial location and scale of our research, (2) development of more flexible funding sources that allow scientists to develop international, interdisciplinary research projects, (3) increased involvement of local knowledge experts and social scientists in all aspects of research design, implementation, interpretation and communication to managers and policymakers.}, keywords = {abstract, abstracts, degradation, ecology, globalization, sustainability}, author = {Jeffrey E. Herrick and Sarukhan, K.} } @article {50460, title = {Arid and Semiarid Rangeland Monitoring in North America}, journal = {Secheresse}, volume = {17}, number = {1-2}, year = {2006}, month = {September 2006}, pages = {235-241}, abstract = {Canada, the United States and Mexico all have a long history of rangeland monitoring. However none have developed a nationwide database or even standardized set of protocols. The lack of standardization, inadequately developed relationships between management objectives and monitoring protocols, and an emphasis on data collection rather than analysis and interpretation have limited the value of past monitoring efforts. The future of monitoring is bright in all three countries. New policies reward ranchers who can document positive changes on their land. Non-equilibrium theory developed in Europe, Africa, Australia and North America increase the value of monitoring data. New protocols increasingly focus monitoring on ecological processes.}, keywords = {arid, arid zone, data base, monitoring, rangeland, rangelands, semi-arid}, url = {/files/bibliography/06-033.pdf}, author = {Jeffrey E. Herrick and Moya, E.G. and Walter Willms and Brandon T Bestelmeyer and Sundt, P. and Barnes, W.} } @inbook {50492, title = {Applications of Remotely Sensed Data from the Jornada Basin}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {305-320}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {15}, address = {New York, NY}, abstract = {The JER and CDRRC have many similarities to other arid rangelands around the world. They are remote with few measurements possible over vast areas. However, like other rangelands, little application of remote sensing data for measurement and monitoring has taken place. Although remote sensing data in the form of aerial photographs were acquired as far back as 1935 over portions of the Jornada Basin, little reliance was placed on these data. With the launch of Earth resources satellites in 1972, a variety of sensors could be used to collect remote sensing data from different platforms, including ground-based towers and hand-held approaches, low-altitude aircraft, high-altitude aircraft and satellites with various resolutions (now as good as 0.61 m) and spectral capabilities. The multispectral, multispatial and multitemporal remote-sensing approach would be ideal for extrapolating ground-based point-and-plot knowledge to large areas or landscape units. The JORNada EXperiment (JORNEX) is designed to acquire a long-term remote-sensing dataset that can be used in concert with the more conventional Jornada Basin LTER long-term data to provide more comprehensive knowledge of rangeland conditions across the landscape.}, url = {/files/bibliography/06-066.pdf}, author = {A. Rango and Jerry Ritchie and T. J. Schmugge and William P. Kustas and M. Chopping}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @article {50573, title = {Application of AVIRIS data in detection of oil-induced vegetation stress and cover change at Jornada, New Mexico}, journal = {Remote Sensing of Environment}, volume = {94}, year = {2005}, note = {//USDA//LTER IV// Received 12/15/2005 // Entered 12/15/2005//}, month = {2005}, pages = {1-16}, abstract = {On June 1, 2000, an oil spill accident occurred along transportation pipeline located in the Jornada Experimental Range (USDA), Jornada,New Mexico, a long-term ecological research (LTER). In order to detect potential vegetation stress caused by the accident, two AVIRIS datasets of the oil spill area, before and after the oil release, are analyzed and the reliability of several techniques in the detection of vegetationstress is examined. The polynomial fitting and Lagrangian interpolation, and spectral mixture analysis (SMA) are applied to the AVIRIS data sets. The firsttwo methods are applied for the detection of the bred-edgeQ shift in vegetation reflectance spectra, and the last for the detection of change invegetation fraction. The results indicate that the polynomial fitting and Lagrangian interpolation both are able to detect a red-shift of thevegetation bred-edgeQ, but the latter{\textquoteright}s performance depends on the band combination used and is sensitive to data noise. The polynomialfitting results are inconsistent in detection of bthe red-edgeQ shift, while Lagrangian interpolation is not. Within the oil spill area, the fractionestimates of vegetation resulting from SMA demonstrate a decrease (10{\textendash}30\%) of the vegetation fraction after the accident, indicating stressedvegetation and cover change. The result also indicates that areas of extremely large decrease (N40\%) in plant cover outside of the oil spill areais due to the response of grasses due to the water stress in 2000, and that the integration of some auxiliary data on ecological andclimatological data with the analysis of remotely sensed data is thus very important to the interpretation of the detection results. A sensitivityanalysis indicates that the detected vegetation cover change is insensitive to the noise introduced by the radiometric normalization.@2004 Elsevier Inc. All rights reserved.}, keywords = {article, AVIRIS data, journal, oil spill, spectral mixture analysis, vegetation stress}, author = {Li, Lin and Ustin, Susan L. and Lay, Mui} } @inbook {50582, title = {Arid and semiarid soils}, booktitle = {Encyclopedia of Soils in the Environment}, year = {2005}, note = {//NONE//LTER IV//ProCite field[6]: In}, month = {2005}, pages = {182-187}, publisher = {Elsevier Ltd.}, organization = {Elsevier Ltd.}, address = {Oxford, U.K.}, abstract = {

Arid and semiarid soils occupy about one-third of the Earth\&$\#$39;s ice-free land surface. They are sources and sinks of atmospheric CO2, sources and sinks (mainly sources) of global dust, and substrate that support high biodiversity of plants and animals. Arid and semiarid soils uniquely accumulate secondary minerals, such as calcite and gypsum, as the result of low rainfall and limited leaching. Because of sparse vegetative cover and high susceptibility to wind and water erosion, many arid and semiarid soils have low resistance and low resilience to disturbance. Hence land degradation (i.e., desertification) is common on most continents with arid and semiarid soils. These dryland soils have been a factor of primary importance in human history. The oldest hominid fossils are found in east Africa in sediments with paleosols containing pedogenic carbonate indicting an arid or semiarid climate. The transition from hunting-and-gathering to agriculture took place in arid and semiarid Mesopotamia about 10,000 years ago. The production of surplus food on the floodplain soils of the Euphrates and Nile gave rise to early civilizations in Sumeria, Babylonia, and Egypt. Today several large urban centers are located on arid and semiarid soils around the world that have adequate groundwater or river water supplies. If irrigated, arid and semiarid soils are an important source of local and global food production. Still, most arid and semiarid land is sparsely populated, open, and often wilderness land.

}, keywords = {book, books, chapter, chapters, climate, soil formation, soil classification, soil formation, soil formation, climate, soil, aridisols, soil, calcite, soil, cambic horizon, soil, classification, soil, description, soil, development, soil, geomorphology, soil, morphology}, author = {Curtis H. Monger and J. Martinez-Rios and Sa{\textquoteright}eb Khresat}, editor = {Hillel, D.} } @conference {50590, title = {Application of Emission-Excitation Fluorescence Spectrum for the Determination of Plants in Goat Diets}, booktitle = {Pittsburg Conference on Analytical Chemistry and Applied Spectroscopy}, year = {2005}, month = {February 26-Marc}, pages = {70}, address = {Orlando, FL}, abstract = {The use of goats for the selective control of invasive shrub in grassland is environmentally desirable. To amplify any genetically based preferences for specific plant species it is necessary to determine the presence of targeted plants in the animals{\textquoteright} diets. Currently there are two proposed techniques for analysis of composition of post- and pre- digested diets, near infrared reflectance spectroscopy (NIRS) and fluorescence spectroscopy. Although NIRS has been successfully used to determine the botanical composition of animal feed, it is limited to the availability of training samples that closely match the animals{\textquoteright} diets. We have proposed the use of multidimensional fluorescence measurements as a detection technique that may be less-sensitive to animal diet variations. Fluorescence intensity response surfaces as functions of both excitation and emission wavelengths have been generated for buffered saline extracts of both feed and fecal samples from a study directed toward the identification of juniper species within goat diets. Classical chemometric techniques have been applied to these data that include multi-way principle components analysis (MPCA) and parallel factor analysis (PARAFAC). The results of these studies will be presented. The implications of those results to the use of fluorescence spectroscopy for the identification of plants in goat diets will be discussed.}, keywords = {diets, emission-excitation, goats}, author = {Pezzotti, C. and Sisk, C.N. and S. Obeidat and G.D. Rayson and D.M. Anderson} } @conference {50594, title = {Applying a new desertification paradigm linking biophysical and socioeconomic elements: the Amapola, Mexico, case study}, booktitle = {Society for Range Management, 58th Annual Meeting and Trade Show}, year = {2005}, month = {February 5, 2005}, pages = {Paper No. 282}, address = {Fort Worth, TX}, abstract = {

The Dahlem Desertification Paradigm (DDP) is a new, interdisciplinary framework stemming from the 88th Dahlem workshop: An Integrated Assessment of the Ecological, Meteorological and Human Dimensions of Global Desertification. The DDP focuses on interrelationships within coupled human-environment systems that cause desertification and is designed to facilitate our ability to compare and contrast arid and semiarid regions of the world. We present elements of the DDP as applied to a case study of severe land degradation in La Amapola, one of the most remote and inaccessible communities of the Ejido Escalerillas, situated on the SE side of the Sierra San Miguelito, SW of San Luis Potosi, Mexico. The structural heterogeneity shaping the Amapola landscape is the product of 150 yrs of human activity and climatic change, where historic legacies remain important. Amapola is a dynamic, coupled human-environmental system dominated by numerous biophysical variables (especially hydrologic phenomena such as soil erosion, gullies, flooding, man-made water reservoirs, etc.) and socioeconomic variables (changing land tenure, federal self-help assistance programs, complex community leadership hierarchies, poverty, etc.). We applied the DDP framework to the degraded Amapola ecosystem to elucidate key linkages between these biophysical and socioeconomic variables with the goal of assessing, for example, the likelihood for increased crop productivity, the potential to extend existing rain-fed and irrigated cultivation via changes in local hydrology, and the relative contribution and interactions of a number of possible degradation triggers, such as overgrazing, hydrologic intervention, and climate variability, especially linkages to the socioeconomic system.

}, keywords = {Amapola, Mexico, biophysical, case study, desertification paradigm, socioeconomic}, author = {J. F. Reynolds and E. Huber-Sannwald and F. Maestre and Jeffrey E. Herrick and Healy, R.} } @article {50593, title = {Aspectos Socioeconomicos Y Biofisicos de la Desertificaction}, journal = {International Journal of Ecology and Evironmental Sciences}, year = {2005}, month = {September 30, 20}, abstract = {Land degradation and desertification are among the most important environmental issues being faced by drylands. Despite its importance and the enormous research effort devoted to it in the last decades, desertification is a topic surrounded by controversy and disagreement. This controversy is rooted in the traditional separation of the biophysical and socio-economic dimensions of desertification, which have been studied separately by scientists from both the natural and the social sciences. This separation has been fueled by the lack of a conceptual and synthethic framework suited to deal with both dimensions simultaneously. In this article we review the main topics surrounding desertification, introduce a new conceptual framework designed to study the biophysical and socio-economic dimensions of desertification simultaneously, review some of the measures being carried out to manage desertified lands and discuss some of the main challenges ahead in the research and management arenas.}, keywords = {degradation, desertification}, url = {/files/bibliography/05-019.pdf}, author = {J. F. Reynolds and F. Maestre and E. Huber-Sannwald and Jeffrey E. Herrick and P. R. Kemp} } @conference {50631, title = {Applications of multi- and cross-scale analyses to management of dynamic systems}, booktitle = {Sixth Symposium on the Natural Resources of the Chihuahuan Desert Region}, year = {2004}, month = {October 15, 2004}, pages = {19}, address = {Alpine, TX}, abstract = {Decades of research on the management and monitoring of Chihuahuan Desert grasslands have emphasized (1) fine-scale patterns, (2) uniformity of dominant processes, and thus (3) standard, vegetation-based protocols for directing and measuring change. Although this was a necessary step, alone it is an insufficient approach to detecting and responding to degradation. We describe recent conceptual and empirical approaches to measuring the variety of pattern and process in vegetation transition based on soil-geomorphic-climate relationships, multiple scales of vegetation/soil pattern, and cross-scale interactions among grass loss in patches, patch connectivity and flux regulation, and climate-forcing functions. These approaches are being used to develop and refine tools that classify different pathways of vegetation response (state-and-transition models) according to soil and climate variables (ecological site descriptions). Pathways featuring cross-scale interactions can explain irreversible and nonlinear rates of change in time and space. These interactions indicate that different processes drive change at particular times and spatial locations, even within same vegetation type. Identification of the dominant processes governing vegetation change indicates the spatial pattern of change. In turn, this pattern indicates the appropriate scale and strategy for monitoring and designing and implementing management responses.}, keywords = {Chihuahuan Desert, climate, cross-scale, geomorphic, management, monitoring, multi-scale, soil, vegetation change}, author = {Brandon T Bestelmeyer and Jeffrey E. Herrick and Kris Havstad and E.L. Fredrickson and Joel R. Brown} } @article {50651, title = {Advances in theory, instrumentation, semiconductor, and materials applications of scanning microscopy}, journal = {Scanning}, volume = {26}, number = {2}, year = {2004}, month = {March 1, 2004}, pages = {68-69}, abstract = {It is important to monitor the development of seasonal snow cover classes (tundra, taiga, alpine, maritime, prairie and ephemeral) worldwide and to visualize and understand snow crystal metamorphism. Low-temperature, scanning electron microscopy provides a superior form of snow crystal imaging and was successfully tested in taiga, alpine and prairie snowpacks with approximately 50\% of the total depth made up of depth hoar crystals. The technique can be used easily for field data collection and provides a new tool for studying important snowpack processes with applications to avalanche and water supply forecasting.}, keywords = {alpine, crystal, maritime, snow, taiga, tundra}, url = {/files/bibliography/04-056.pdf}, author = {J. Foster and A. Rango and E. G. Josberger and E. R. Erbe and C.D. Pooley and W.P. Wergin} } @article {50659, title = {An algorithm to address the MODIS bowtie effect}, journal = {Canadian Journal of Remote Sensing}, volume = {30}, number = {4}, year = {2004}, month = {August 1, 2004}, pages = {644-650}, abstract = {

A snow cover mapping and snowmelt runoff forecasting system is currently being operated at the USDA-ARS Jornada Experimental Range. Snow-covered area is being used as an input for snowmelt runoff forecasting and has been traditionally derived from NOAA-AVHRR (National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer) channels 1 and 2. Both the snow maps and the snowmelt runoff forecasts are being sent to water resources agencies and companies for decision making in water management. The quality of the snow maps can be improved using the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on board the Terra platform. MODIS channels 1 and 2 are centered in similar wavelengths as AVHRR channels 1 and 2 but with 250-m resolution instead of 1 km off AVHRR channels. The recent implementation of MODIS data has been complicated by the so-called "bowtie effect" of the MODIS instrument, which causes an overlap of the satellite field of view producing a data repetition. This effect increases with the distance from nadir and can be especially dramatic at the edge of the image.

}, keywords = {algorithm, bowtie effect, MODIS}, doi = {10.5589/m04-028}, url = {/files/bibliography/04-055.pdf}, author = {E. Gomez-Landesa and A. Rango and M. Bleiweiss} } @conference {50718, title = {Arid ecosystem responses to variations in the frequency and magnitude of growing season precipitation}, booktitle = {89th Annual Meeting, Ecological Society of America}, year = {2004}, month = {August 1, 2004}, pages = {Abstract p. 476}, address = {Portland, OR}, abstract = {Global climate change models predict regional changes in average seasonal precipitation, but few models or experiments address how changes in the delivery of precipitation within the growing season will affect ecosystem responses. Arid systems differ from mesic systems in that water availability is frequently low enough to severely restrict biological activity. Consequently, the frequency and magnitude of precipitation events, which dictate the length and severity of intervening dry periods, may have substantial effects on ecosystem function regardless of the total amount of seasonal rainfall. We examined how a 60 mm increase in summer precipitation (46\% increase over mean summer rainfall) applied with two different frequencies and magnitudes during the growing season affected carbon, water and nitrogen dynamics of a Chihuahuan Desert scrub ecosystem. Plots containing mesquite (Prosopis glandulosa) and black grama grass (Bouteloua eriopoda) were assigned to either: ambient precipitation (controls), ambient plus frequent small (5-6 mm) rainfall events applied weekly, and ambient plus infrequent large (20-24 mm) events applied monthly. Mesquite used rainfall from 5 mm and 24 mm storms, as evidenced by increased stem elongation, improved water status and uptake of deuterium-labeled rainfall, but mesquite response was greater under large infrequent rainfalls. Daytime measurements of net ecosystem carbon exchange on subplots containing soil, plant roots and biological soil crusts indicated biological soil crust photosynthesis was improved by frequent small rainfalls. Keeling plot analyses of d13C of respired CO2 during dark hours indicated that the contribution from different sources (roots, microbes and soil crusts) varied with rainfall treatment. Both infrequent large rainfalls and frequent small rainfalls significantly increased nitrogen availability, especially in the surface soil. We found that changes in the depth and duration of soil wetting, resulting from different precipitation patterns, have important implications for ecosystem carbon and nitrogen dynamics because of the differential sensitivity of ecosystem components.}, keywords = {arid systems, climate change, ecosystem responses, growing season precipitation}, author = {K. A. Snyder and Cable, J.M. and T. Huxman and S. Tartowski} } @article {50741, title = {Atypical morphology of dark septate fungal root endophytes of Bouteloua in arid southwestern USA rangelands}, journal = {Mycorrhiza}, volume = {135}, year = {2003}, month = {October 1, 2003}, pages = {239-247}, abstract = {Roots of native grama grasses (Bouteloua sp) analyzed for internal colonization of fungal endophytes using histochemical stains and differential interference microscopy. Unique and atypical fungal structures were found to form a continuous nonpathogenic colonization of sieve elements, cortical, epidermal cells, and the root hairs and surface. Unique interfaces with sieve elements, the accumulation of large quantitie of lipids and their distribution throughout the root and the deposition of mucilage on the root surface indicates that dark septate fungi manage carbon between the plant and soil and protect the plant from drought stress. The nondestructive colonization of sieve elements suggests a novel plant-fungal association not previously reported.}, keywords = {Bouteloua, fungal endophytes, grama grasses, structures}, url = {/files/bibliography/03-045.pdf}, author = {J.R. Barrow} } @conference {50744, title = {Ants and termites: The little things that run your ranch}, booktitle = {56th Annual Meeting, Society for Range Management}, year = {2003}, month = {February 1-6, 20}, address = {Casper, WY}, abstract = {Ants and termites are very abundant, active, and species-rich animal groups in rangelands. One can hardly take a step without seeing evidence of their presence. As a consequence, these animals are intimately tied to many parts of rangeland functioning. The burrowing activities of ants and termites can be critical to maintaining soil quality and infiltration in the short-term and soil development over the long-term. These animals also have important effects on nutrient transport, retention, and availability in soils. The many species of inconspicuous, scavenging ants are largely responsible for removing dead animal matter into the soil. Where termites are abundant, their consumption of dead plant material may regulate, and actually decrease, the amount of organic matter in soils. But, ants and termites are also reservoirs of nutrients such as nitrogen and phosphorus. These nutrients are stored in their bodies and are released during nuptial flights after rains at points in time when they can be rapidly incorporated by other life forms. Ants are also important consumers of seeds and plants. Thus, the activities of ants and termites directly and indirectly affect plant production as well as the diversity of other rangeland organisms. Luckily, ants and termites are forgiving animal groups with respect to current and historical overgrazing in many rangelands. Nonetheless, observing the activities of these groups and understanding their significance can aid in gauging the health of rangelands as well as enjoying them.}, author = {Brandon T Bestelmeyer and Walter G. Whitford} } @article {50749, title = {Applying species diversity theory to land management}, journal = {Ecological Applications}, volume = {13}, number = {6}, year = {2003}, month = {December 1, 2003}, pages = {1750-1761}, abstract = {

Many theories and hypotheses have been proposed to explain patterns of species diversity and distribution/abundance at particular scales, but they are often unclear on how these ideas relate or how they apply across multiple scales. It has been difficult to use diversity theory to understand patterns at the intermediate scales at which biodiversity is managed. Here, we present a framework for studying diversity based on the ecological processes influencing distribution of organisms at different scales. We use this framework to organize diversity theories into several classes. The framework highlights that processes contributing to diversity patterns depend on the characteristics of the taxa considered, the spatial scales at which organisms respond to environment, and the scales and other characteristics of the particular environments in which investigators hope to explain variation in diversity. At the scales traditionally considered by land managers and conservation biologists, biodiversity is determined b the interactions among habitat occupancy, landscape distribution, and geographic range for a variety of taxa. The framework suggests that, in each case, managers should address the following general questions: 1) which groups of organisms will be considered, 2) how do their domains of scale relate to the land area under consideration, 3) what processes are likely to be important determinants of species distribution at management scales, and 4) how will the proposed management activities interact with these processes? We emphasize the value of considering species diversity theories in a pluralistic and case-specific way, rather than seeking singular explanations or "general laws" explaining diversity variations.

}, keywords = {Chihuahuan Desert, competition, conservation, dispersal, land management, landscape ecology, limitation geographic, macroecology, natural resources management, range habitat, Selection, species diversity}, doi = {10.1890/02-5089}, url = {files/bibliography/JRN00376.pdf}, author = {Brandon T Bestelmeyer and J.R. Miller and J.A. Wiens} } @proceedings {50782, title = {Application of ecological assessment and monitoring to (adaptive) sustainable land management}, year = {2003}, month = {September 8-12, }, pages = {21-30}, address = {Venecia, Durango, Mexico}, abstract = {Assessment and monitoring are necessary to continuously adapt management to ensure it is meeting land management objectives. Ecologically based assessment and monitoring are required for sustainable land management because long-term sustainability depends on maintaining particular ecological processes. This paper reviews several relatively new concepts, including ecological resistance and resilience and ecological, management and economic thresholds. These concepts are required to use assessment and monitoring to increase sustainability. The paper concludes with a description of a system for combining short- and long-term monitoring as part of a cost-effective adaptive management program.}, author = {Jeffrey E. Herrick and Brandon T Bestelmeyer} } @conference {50822, title = {ASTER observations of surface temperature and emissivity over New Mexico test sites}, booktitle = {Fall 2003 Meeting, American Geophysical Union}, volume = {84}, number = {46}, year = {2003}, month = {December 8-12, 2}, pages = {F634}, address = {San Francisco, CA}, abstract = {The multispectral thermal infrared data obtained from the Advanced Spaceborne Thermal Emission and Reflection (ASTER) radiometer on NASA{\textquoteright}s Terra satellite have been of good quality and provide a unique new tool for studying the land surface. ASTER has five bands in the 8-12 micrometer waveband with 90 m spatial resolution; when the data are combined with the Temperature Emissivity Separation (TES) algorithm, the surface emissivity over this wavelength region can be determined along with the surface temperature. This paper will present some quantitative emissivity and temperature results obtained over test sites in southern New Mexico (the Jornada Experimental Range and the White Sands National Monument). These results are compared with ground observations. The Jornada site is typical of a desert grassland where the main vegetation components are grass and shrubs with a large fraction of exposed soil, while the White Sands site is mainly dunes of gypsum sand which provides a good relatively homogenous emissivity target with an interesting spectral signature. More than two dozen ASTER scenes over these New Mexico test sites have been acquired since the launch of Terra in December 1999. There were simultaneous field campaigns in May of 2000-2003 and September/October 2001 and 2002. Also, ASTER (MODIS-ASTER airborne simulator) coverage was obtained for several of the dates. The ASTER surface brightness temperatures compare very well with those obtained on the ground. The results appear to be in good quantitative agreement with laboratory measurements of the emissivity for the quartz rich soils of the Jornada with values less than 0.85 for the 8-9 micrometer channels. For the longest wavelength channels little spatial variation of the emissivity was observed with values of 0.96 +/- 0.005 over large areas. Emissivity values from the ASTER data for the gypsum at White Sands were in good agreement with values calculated from the lab spectra for gypsum and with each other. Gypsum has a strong emissivity minimum centered on the ASTER 8.63 micrometer band , and the satellite results for this band agree within 0.01 of the value calculated from the laboratory spectra. The extension of these results to mapping emissivity over large areas will be presented in the form of an emissivity map for the deserts of North Africa.}, author = {T. J. Schmugge and Ogawa, K. and A.N. French and A.F. Hsu and Jerry Ritchie and A. Rango} } @inbook {50878, title = {Animal Husbandry}, booktitle = {Encyclopedia of Global Change}, volume = {I}, year = {2002}, month = {2002}, pages = {39-42}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York, NY}, abstract = {Animal agriculture has evolved with the growth of the human population from 4 million people 10,000 years before the present (ybp) to the 5.85 billion people that occupy the world today. Domestication of a relatively few of the available mammalian species initially occurred in conjunction with climatic, cultural and societal changes at the end of the last ice age - the Wisconsin deglaciation. Agrarian-based communities developed independently around the world, and animal husbandry practices became common. Today, despite tremendous technological advances in genetics (e.g., cloning), physiological manipulations (e.g., artificial insemination) and nutritional provisions (e.g., high quality harvested forages), there are still only a few domesticated species used in animal agriculture, and traditional animal husbandry practices are still universally applied. In 1996, the world population of domesticated grazing livestock was approximately 3.3 billion, an increase of 1.1 billion during the last five decades despite a relatively constant total amount of grazeable land. The bulk of this increase during the last half of the 20th century is due to a near doubling of cattle, sheep and goats on the continents of Asia and Africa. The impacts of unmanaged grazing animals have been substantial through the course of human history. The modern principles for proper management of grazing lands developed during this century in response to destructive impacts of unmanaged grazing throughout the world.}, url = {/files/bibliography/02-107.pdf}, author = {Kris Havstad} } @conference {50876, title = {Applications of scaling approaches to restoring ecosystems}, booktitle = {87th Annual Meeting, Ecological Society of America}, year = {2002}, month = {August 4, 2002}, pages = {24}, address = {Tucson, AZ}, abstract = {Landscape remediation will require extensive practices applied at small spatial scales and improved understanding of landscape dynamics that will trigger large-scale processes. Anthropogenic disturbances that result in degradation of ecosystems often are initiated at relatively small scales. These disturbances can disrupt small-scale processes and cascade to affect processes at larger spatial scales. Eventually, degradation is expressed at landscape, regional or larger scales and any reasonable prospects for effective remediation are poor. We use the response to livestock overgrazing arid rangelands in the southwest USA as an example of these multiscale phenomena. Initial (late 19th century) overgrazing impacts occurred over relatively small spatial extents and affected only small-scale vegetation processes. Eventually, the impacts of these disturbances accumulated to result in landscape-scale degradation that affected larger scale processes, such as plant dispersal, fire regimes, and productivity. In addition, changes in regional climatic patterns, continued livestock grazing, and introduction of non-native species complicated remediation efforts. Areas where degradation has been successful are generally small in extent and are the result of resilient soil/vegetation systems or responses to costly practices. As yet, we have not observed the reversal of degradation at large scales due to cascading effects of remediation practices implemented at small scales.}, author = {Kris Havstad and Joel R. Brown} } @article {50882, title = {Application of soil quality to monitoring and management: Paradigms from rangeland ecology}, journal = {Agronomy Journal}, volume = {94}, number = {1}, year = {2002}, month = {January 1, 2002}, pages = {3-11}, abstract = {

Recent interest in soil quality and rangeland health, and the large areas set aside under the USDA Conservation Reserve Program, have contributed to a gradual convergence of assessment, monitoring and management approaches in croplands and rangelands. The objective of this paper is to describe a basis for integrating soils and soil quality into rangeland monitoring, and dthrough monitoring, into management. Previous attempts to integrate soil indicators into rangeland monitoring programs have often failed due to a lack of understanding of how to apply those indicators to ecosystem function and management. We discuss four guidelines which we have used to select and interpret soil and soil quality indicators in rangelands, and illustrate them using a recently developed rangeland monitoring system. The guidelines include 1) identifying a suite of indicators that are consistently correlated with the functional status of one or more critical ecosystem processes including those related to soil stability, soil water infiltration, and the capacity of the ecosystem to recover following disturbance, 2) basing indicator selection on inherent soil and site characteristics and on site- or project-specific resource concerns, such as erosion or species invasion, 3) using spatial variability in developing and interpreting indicators to make them more representative of ecological processes, and 4) interpreting indicators in the context of an understanding of dynamic, non-linear ecological processes which are defined by thresholds. The approach defined by these guidelines may serve as a paradigm for applying the soil quality concept in other ecosystems, including forests and ecosystems managed for annual and perennial crop production.

}, keywords = {monitoring programs, rangeland ecology, rangeland health, soil indicators, soil quality}, url = {/files/bibliography/02-032.pdf}, author = {Jeffrey E. Herrick and Joel R. Brown and A.J. Tugel and P. L. Shaver and Kris Havstad} } @inbook {50913, title = {Arid Soils}, booktitle = {Encyclopedia of Soil Science}, year = {2002}, note = {//LOCAL, NMSU, USDA//LTER IV//}, month = {2002}, pages = {84-88}, publisher = {Marcel-Dekker}, organization = {Marcel-Dekker}, abstract = {Describes arid soils of river floodplains, on uplands, as well as types of arid soils and their ecological significance.}, keywords = {arid soil, book, books, chapter, chapters, report, reports, soil, soil formation, soil, argillic horizon, soil, calcic horizon, soil, carbonate, soil, petrocalcic horizon}, author = {Curtis H. Monger}, editor = {R. (ed.) Lal} } @proceedings {50940, title = {ASTER observations of the spectral emissivity over New Mexico}, volume = {4542}, year = {2002}, note = {ARIS entry made by Beltsville}, month = {09/2002}, pages = {207-213}, address = {Toulouse, France}, abstract = {

On several days in 2000 and 2001 the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) on the Terra satellite obtained data over the Jornada Experimental Range test site along the Rio Grande river and the White Sand National Monument in New Mexico. ASTER has 14 channels from the visible (VNIR) through the thermal infrared (TIR) with 15 m resolution in the VNIR and 90 m in the TIR. The overpass time is approximately 11 AM (MST). With 5 channels between 8 and 12 micrometers these multispectral TIR data from ASTER provide the opportunity to separate the temperature and emissivity effects observed in the thermal emission from the land surface. Ground measurements during these overflights included surface temperature, vegetation type and condition and limited surface emissivity measurements. Preliminary results indicate good agreement between ASTER emissivities and ground measures. Analysis of earlier aircraft data has shown that the multispectral TIR data are very effective for estimating both the surface temperature and emissivity. These results will be compared with those obtained from the ASTER data for this site. With multispectral thermal infrared observations provided by ASTER it is possible for the first time to estimate the spectral emissivity variation for these surfaces on a global basis at high spatial resolution.

}, keywords = {ASTER, emissivity, gypsum, remote sensing, Terra, Thermal infrared}, url = {/files/bibliography/02-078.pdf}, author = {T. J. Schmugge and A.N. French and Jerry Ritchie and M. Chopping and A. Rango} } @proceedings {50939, title = {ASTER thermal infrared observations over New Mexico}, volume = {I}, year = {2002}, month = {June 24-28, 2002}, pages = {24-26}, address = {Toronto, Canada}, abstract = {Excellent ASTER scenes over our New Mexico Jornada test site were acquired on May 9, 2000, February 12, May 12, July 22, September 17, October 19 and November 11, 2001. There were simultaneous field campaigns for the May 9, May 12 and September 17 scenes. Also, MASTER coverage was obtained for the May 12 scene. The White Sands National Monument was also within several of fthe scenes. Emissivity values from the ASTER data from the May 9 and May 12 scenes for the gypsum sand at White Sands were in good agreement with values calculated from the lab spectra for gypsum and with each other except for band 10. At the Jornada grass site, the agreement between the ASTER results and those calculated from the lab spectra was very good. This is a little surprising because there is generally a mix of bare soil and sensecent vegetation at this site, so we would have expected to see a flatter spectral response due to the vegetation. The results for the Jornada mesquite site show a larger difference between the lab results and the ASTER results; e.g., 0.05 for the 8.29 micron channel. These results indicate ASTER and TES are working very well. The surface brightness temperatures from ASTER were in reasonable agreement with measurements made on the ground during the field campaigns mentioned above.}, url = {/files/bibliography/02-090.pdf}, author = {T. J. Schmugge and A.N. French and Jerry Ritchie and M. Chopping and A. Rango} } @inbook {50954, title = {Ants}, booktitle = {Encyclopedia of Soil Science}, year = {2002}, month = {July 8, 2002}, pages = {76-79}, publisher = {Marcel Dekker, Inc.}, organization = {Marcel Dekker, Inc.}, address = {Columbus, OH}, abstract = {Ants are among the most ubiquitous insects on the planet. They occur in all biomes except for the extreme polar regions. In the biomes where ants are abundant, they affect many soil processes that contribute to the creation of patch mosaics that characterize the soils and vegetation of many landscapes. The abundance and diversity of soil-nesting ants varies from as high as 7,000 colonies per hectare in tropical savanna to as few as 3-4 colonies per hectare on some periodically flooded, fine-textured soil, desert landscape units. Soil-nesting ants affect critical ecosystem processes, such as nutrient cycling and water redistribution. Ant nest mounds vary from a few centimeters in height and diameter to less than 1 m in height and less than 2 m diameter. Ant nests consist of underground, branched networks of galleries and chambers. Surficial chambers are connected to lower chambers by vertical galleries with branching lateral galleries. Galleries and chambers vary in size and number depending on the species of ant. For example, Lasius neoniger, an abundant ant species in temperate North America, constructs tubular galleries of 1.5-5.0 mm in diameter and chambers of 10-20 mm diameter and 30-50 mm in length. The volume of L. neoniger nests range from 20-250 cm (to the third power) and are confined to the upper 70 cm of soil (3). Other species construct nests to depths ranging from 50 cm to greater than several meters, depending on species-specific behavior, soil type, and landscape position. Soil profile mixing, texture, physical and chemical property modification of mound soils, soil macroporosity, and geomorphological attributes of ant nest mounds vary with species-specific colony longevity, body size, and numbers of workers of a colony, soil type, and landscape position. The pedturbation effects of ants are, therefore, dependent on the species composition of the ant community, geomorphic history, soil properties, and topographic position of a landscape unit. Because most studies of the effects of ants on soils have focused on one or two species, a comprehensive analysis of the combined effects of all ant species on the soils of an ecosystem cannot be made.}, url = {/files/bibliography/02-084.pdf}, author = {Walter G. Whitford}, editor = {R. (ed.) Lal} } @article {50961, title = {Animal control system using global positioning and instrumental animal conditioning}, year = {2001}, month = {May 15, 2001}, address = {USA}, abstract = {

A device worn externally (or parts of which may be inserted in the ear canal) by an animal which uses a programmable repertoire of bilaterally applied aversive stimuli for the autonomous control of an animal{\textquoteright}s location and direction of movement is disclosed. Electromagnetic signals and electro-mechanical hardware are activated through a dedicated, embedded computer system, that allows a cascade of one or more aversive stimuli, normally acoustic and/or electrical stimulation, to be bilaterally applied to either the right or left side of an animal as a cue to change its location through a specific direction of movement. Aversive stimuli are programmed to be administered only when an animal penetrates a predetermined boundary. The embedded computer uses satellite position system data to determine the animal{\textquoteright}s location with respect to the closest boundary line and then calculates when and to which side of the animal the repertoire of bilateral aversive stimuli is to be applied.

}, keywords = {animal conditioning, animal control, global positioning, instrumental, patent}, isbn = {US 6,232,880 B1}, url = {/files/bibliography/01-005/pdf}, author = {D.M. Anderson and C.S. Hale and Deck, R.E.}, editor = {U.S. Patent Office} } @article {50969, title = {Ant biodiversity in semiarid landscape mosaics: The consequences of grazing vs. natural heterogeneity}, journal = {Ecological Applications}, volume = {11}, number = {4}, year = {2001}, month = {August 1, 2001}, pages = {1123-1140}, abstract = {

Conservation of biodiversity in landscape mosaics requires us to understand the impacts of human land use within mosaic elements and an evaluation of the biological uniqueness of different elements. We examined patterns of ant diversity in three semiarid rangeland landscapes used predominantly for grazing. Within each landscape, we compared the effects of grazing and natural variation in soils and vegetation on ant diversity and community composition. Grazing had little effect on ant richness, diversity, or composition at the transitional zone or the desert grassland site; but, ungrazed areas at the shortgrass steppe site had a higher overall richness and favored the abundance of some species. Some samples of saltbush (Atriplex canescens) shrubland were similar to ungrazed samples in richness and species composition. In both the transitional zone and the desert grassland, creosotebush (Larrea tridentata)-dominated habitats harbored comparatively species-rich and distinct ant communities. Also, mesquite (Prosopis glandulosa) coppice dunes at the desert grassland site favored the abundance of several rare species. Canonical correspondence analysis revealed that variation in soil hardness and texture best explained community variation at the shortgrass steppe site, whereas soil texture and associated differences in shrub density best explained differences in composition at the transitional and desert grassland sites. While habitat characterization based on vegetation classification did not adequately reflect environmental variation important to ants in shortgrass steppe, it reflected important soil textural variation in the transitional and desert grassland sites. This suggests that ant conservation in these semiarid rangelands should emphasize patterns of variation in soil properties.

}, keywords = {ants, canonical correspondence analysis, desert grassland, diversity, formicidae, grazing, habitat classification, shortgrass steppe, soil texture}, doi = {10.1890/1051-0761(2001)011[1123:ABISLM]2.0.CO;2}, url = {/files/bibliography/01-014.pdf}, author = {Brandon T Bestelmeyer and J.A. Wiens} } @proceedings {50971, title = {An approach to managing landscape pattern and dynamics in southern New Mexico}, year = {2001}, month = {April 1, 2001}, address = {Las Cruces, NM}, 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 that determine 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 feedbacks 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.}, keywords = {classifying, dynamics, ecological site concept, landscape pattern, landscape units, management}, url = {http://agecon.nmsu.edu/nmsrm/}, author = {Brandon T Bestelmeyer and Joel R. Brown and Kris Havstad and Alexander, R. and Chavez, G. and Jeffrey E. Herrick} } @proceedings {50994, title = {Addressing the MODIS bowtie effect for snow mapping}, year = {2001}, note = {As of 5/17/03, still in press.}, month = {October 2-5, 200}, address = {Montpellier, France}, abstract = {A snow cover mapping and snowmelt runoff forecasting system is being operated at the U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS), Jornada Experimental Range. Snow-covered area is used as input for snowmelt runoff forecasting and has been traditionally derived from National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer (NOAA-AVHRR) channels 1 and 2. The snow maps and snowmelt runoff forecasts are used by water resource agencies and companies in water management decision making. The quality of the snow maps is improved using the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument, but the data is complicated by the "Bowtie Effect" that causes an overlap of the satellite field of view producing data repetition. An algorithm was developed to resample the MODIS image in latitude and longitude coordinates. The algorithm reads groups of 40 rows of image pixels and groups of 10 rows of latitude and longitude values placing each image pixel in the correspondent position of an output file in latitude and longitude coordinates. The final position of each pixel is determined by 2 linear bidimensional interpolations in the latitude and longitude space, giving 2 plans approaching the local variations of latitude and longitude. The equations of these planes are derived independently for latitude and longitude; for each case it uses 3 values of latitude and longitude. A concern is the relation between rows and columns of output images which can vary strongly within one single image and near polar regions. Appearance of gaps was expected and detected at the edges of the output file due to lack of information in those areas. These problems are overcome when the algorithm is applied to small areas and far from polar regions.}, author = {E. Gomez-Landesa and A. Rango and M. Bleiweiss} } @article {50992, title = {Assessment of MODIS channels 1 and 2 for snow mapping capability}, journal = {EOS Transactions, American Geophysical Union}, volume = {81}, year = {2001}, note = {//NONE//LTER IV//}, month = {2001}, pages = {548}, author = {E. Gomez-Landesa and A. Rango} } @mastersthesis {51011, title = {Aeolian particulate matter as a function of soil surface texture and vegetative cover : Jornada Basin, New Mexico}, year = {2001}, note = {//USDA//NONE// Received and Entered 12/15/2005ProCite field[12]: Not in File}, month = {2001}, pages = {70}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, 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. [excerpted from published work in JAE, Hupy (2004)]{\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, crusty type, dissertation, rangelands, saltation, theses, thesis, vegetation cover, wind erosion}, author = {Joseph P. Hupy} } @article {51023, title = {Ant communities and livestock grazing in the Great Basin, USA}, journal = {Journal of Arid Environments}, volume = {49}, number = {4}, year = {2001}, month = {December 1, 2001}, pages = {695-710}, abstract = {

The objectives of this study were to determine if metrics for ant species assemblages can be used as indicators of rangeland condition and to determine the influence of vegetation and ground cover variables, factors often influenced by livestock grazing, on ant communities. The study was conducted in two areas in the Great Basin: a sagebrush-steppe in southeastern Idaho (n = 30 sites) and salt-desert shrub in western Utah (n = 27 sites). Sites were selected based on known rangeland conditions (i.e., good, fair, poor) associated with livestock grazing. Ant communities differed considerably between the two study areas. Collectively, more ant species occurred at the Idaho sites (30) than at the Utah sites (21), relatively few species (8) occurred in both areas, species richness was significantly greater at the Idaho sites (mean = 12(.)0 species) than the Utah sites (mean = 6(.)9 species), and Formica spp. were diverse (total of 15 species) at the Idaho sites but rate (1 species) at the Utah sites. In Idaho, all species collectively, generalists and Formica spp., were significantly less abundant on sites in poor condition than that on sites in good or fair condition; whereas in Utah, seed harvesters and Pheidole spp. were significantly more abundant on sites in poor condition than on sites in good or fair condition. In Idaho, species richness was significantly lower on sites in poor condition. In Idaho, species richness and relative abundances of several ant groups were significantly related to bare patch size and parameters for cover or species richness of several vegetation groups. In contract to the comparisons involving sites in poor condition, no differences in any communities in either Idaho or Utah were evident between sites in good and fair condition. Thus, the ant communities responded only to large changes in rangeland condition and to large differences in climatic/edaphic conditions between the two areas. Hence, ant community metrics appear to have limited utility as indicators of rangeland condition in the Great Basin.

}, doi = {10.1006/jare.2001.0824}, url = {files/bibliography/01-JrnArdEnviron-Whitford.pdf}, author = {M. S. Nash and Walter G. Whitford and Bradford, D.F. and Franson, S.E. and A.C. Neale and Heggem, D.T.} } @proceedings {51033, title = {Application of molecular fluorescence spectroscopy for the elucidation of diet composition for free-ranging herbivores}, volume = {41}, year = {2001}, month = {April 1, 2001}, pages = {785-790}, abstract = {This research focuses on the use of multidimensional fluorescence measurements for rapid, objective identification of those plants eaten by specific animals. It enables the collection of multidimensional response surfaces to define the species-specific signatures. Initial work has concentrated on the generation of a spectral database for tobosa hay, mesa dropseed, spectacle pod, pale globemallow, tarbush and four-wing salt bush Normalized average spectra of chloroform extracts from triplicate samples of at least five different plants yielded significant spectral signatures in the wavelength region of 400-600 nm. The spectra suggest distinguishing different species using their respective spectral fluorescence signatures would be relatively simple. One approach to generation of identifying criteria has been deconvolution of the measured spectral envelope into separate components. This approach provides spectroscopically relevant parameters for applying pattern recognition and regression analysis algorithms to identification of plant species in complex mixtures. This technique can lead the way to a rapid, accurate and precise method to investigate the dietary habits of rangeland animals.}, keywords = {diet composition, fluorescence measurements, free-ranging herbivores, multidimensional}, url = {/files/bibliography/01-046.pdf}, author = {G.D. Rayson and T.L. Danielson and D.M. Anderson and Richard E. Estell and E.L. Fredrickson and Kris Havstad} } @article {51036, title = {Airborne LASER technology for measuring rangeland conditions}, journal = {Journal of Range Management}, volume = {54}, number = {2}, year = {2001}, note = {ARIS entry by Beltsville July 9, 2000}, month = {March 1, 2001}, pages = {A8-A21}, abstract = {Land surface and vegetation properties are key for understanding range conditions. Ground-based measurements of these properties are difficult and time consuming. Profiling and scanning airborne laser altimeter systems provide an alternative method to quickly and easily measure land surface and vegetation features and properties for large land areas. The agreement between airborne laser altimeter and field measurements is good for topographic features, vegetation properties (i.e., height, cover), and surface roughness. This paper presents examples of the applications of profiling and scanning airborne lasers as additional tools in the arsenal of remote sensing tools used to monitor rangeland conditions. Airborne laser measurements of plant canopy properties across the landscape and their effects on aerodynamic roughness allow better understanding of evaporative losses, infiltration, and surface water movement. Laser measurements improve our understanding of the effect of canopy and landscape roughness on rangelands conditions.}, url = {http://uvalde.tamu.edu/jrm/remote/srm-laser.pdf}, author = {Jerry Ritchie and M. S. Seyfried and M. Chopping and Y. Pachepsky} } @proceedings {51040, title = {ASTER observations of spectral emissivity for arid lands}, year = {2001}, note = {//?//LTER IV//Updated 01/04/2006}, month = {2001}, pages = {II:715-717}, address = {Sydney, Australia}, abstract = {

On May 9, 2000 the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) on the Terra satellite obtained data over the Jornada Experimental Range test site along the Rio Grande river and the White Sand National Monument in New Mexico. ASTER has 14 channels from the visible and near-infrared (VNIR) through the thermal infrared (TIR) with 15 m resolution in the VNIR and 90 m in the TIR. The overpass time is approximately 11 a.m. With 5 channels between 8 and 12 μm these multispectral TIR data from ASTER provide the opportunity to separate the temperature and emissivity effects observed in the thermal emission from the land surface. Ground measurements during these overflights included surface temperature, vegetation type and condition and limited surface emissivity measurements. There was also an aircraft flight with the MODIS/ASTER simulator on June 14, 2000, unfortunately not coincident with a satellite overpass. Preliminary results indicate good agreement between ASTER brightness temperatures and ground measures. Analysis of earlier aircraft data has shown that the multispectral TIR data are very effective for estimating both the surface temperature and emissivity. These results will be compared with those obtained from the ASTER data for this site. With multispectral, thermal infrared observations provided by ASTER it is possible for the first time to estimate the spectral emissivity. variation for these surfaces on a global basis at high spatial resolution

}, keywords = {abstract, abstracts, arid lands, ASTER, remote sensing, conference, conference proceedings, conferences, emissivity, proceeding, proceedings}, url = {files/bibliography/01-078.pdf}, author = {T. J. Schmugge and A.N. French and Jerry Ritchie and M. Chopping and A. Rango} } @conference {51043, title = {ASTER observations of spectral emissivity over New Mexico}, booktitle = {8th International Symposium on Remote Sensing, Agriculture Ecosystems and the Environment}, year = {2001}, note = {ARIS entry made by Beltsville; symposium sponsored by SPIE.}, month = {September 17-20,}, pages = {118, Abstract No. 4542-30}, address = {Toulouse, France}, abstract = {With the successful launch of NASA{\textquoteright}s Terra satellite in December 1999 a new tool for observing land surface properties becomes available, i.e. multispectral thermal infrared data from the Advanced Spaceborne Thermal Emission Reflectance Radiometer (ASTER) instrument. ASTER has 5 channels in the 8 to 12 micrometer wave band with 90 meter resolution. These data can be used to assess the spectral variations of surface emissivity. Knowledge of the surface emissivity is important for determining the radiation balance at the land surface. For arid lands with sparse vegetation the problem is difficult because the emissivity of the exposed soils and rocks is highly variable. We will present some early ASTER data acquired over the Jornada Experimental Range and White Sand National monument in New Mexico on May 09, 2000 and May 12, 2001. The Jornada site is typical of a desert grassland where the main vegetation components are grass and shrubs. The Temperature Emissivity Separation (TES) algorithm is used to extract the temperature and 5 emissivities from the 5 channels of ASTER data. TES makes use of an empirical relation between the range of observed emissivities and their minimum value. Good quantitative agreement with laboratory measurements was found for the emissivities extracted for the gypsum sands of the White Sands. This target is the only one that was relatively uniform over the ASTER footprint. For the site within the Jornada the results were quantitatively consistent with ground measurements.}, author = {T. J. Schmugge and A.N. French and Jerry Ritchie and A. Rango} } @proceedings {51039, title = {ASTER observations of the spectral emissivity of arid lands}, volume = {III}, year = {2001}, note = {ARIS entry by Beltsville}, month = {2001}, pages = {715-717}, abstract = {

On May 9, 2000 the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) on the Terra satellite obtained data over the Jornada Experimental Range test site along the Rio Grande river and the White Sand National Monument in New Mexico. ASTER has 14 channels from the visible and near-infrared (VNIR) through the thermal infrared (TIR) with 15 m resolution in the VNIR and 90 m in the TIR. The overpass time is approximately 11 a.m. With 5 channels between 8 and 12 μm these multispectral TIR data from ASTER provide the opportunity to separate the temperature and emissivity effects observed in the thermal emission from the land surface. Ground measurements during these overflights included surface temperature, vegetation type and condition and limited surface emissivity measurements. There was also an aircraft flight with the MODIS/ASTER simulator on June 14, 2000, unfortunately not coincident with a satellite overpass. Preliminary results indicate good agreement between ASTER brightness temperatures and ground measures. Analysis of earlier aircraft data has shown that the multispectral TIR data are very effective for estimating both the surface temperature and emissivity. These results will be compared with those obtained from the ASTER data for this site. With multispectral, thermal infrared observations provided by ASTER it is possible for the first time to estimate the spectral emissivity. variation for these surfaces on a global basis at high spatial resolution

}, keywords = {ASTER observations, distribution, northern Chihuahuan Desert, soil resources, stability}, url = {/files/bibliography/01-078.pdf}, author = {T. J. Schmugge and A.N. French and Jerry Ritchie and M. Chopping and A. Rango} } @article {51046, title = {Aggregate stability kit for soil quality assessments}, journal = {CATENA}, volume = {44}, number = {1}, year = {2001}, month = {2001}, pages = {37-45}, abstract = {

Soil aggregate stability is an important indicator of soil quality. For soil quality assessment, there is a need for a quantitative field method for measuring aggregate stability that is simple to perform, low cost, and available for routine assessments by land managers. A method is presented that follows the commonly used or standard single-sieve wet-sieving method for aggregate stability. A combination manual sieving and drying apparatus is constructed from a trunk-style tackle box. Sieves are constructed from 60 mesh screen and PVC reducing adapters. The method requires manual sieving, 30 cycles for minute for three minutes. Percent water aggregate stabilities from the manual sieving method are comparable to the mechanical wet sieving method. The new method was able to distinguish differences in aggregate stability caused by differences in soil type and land use. This method can provide a low cost, reliable and sensitive tool that can be used din conjunction with other measurements to assess soil quality.

}, keywords = {aggregate stability, drying apparatus, field method, manual sieving, soil quality}, doi = {10.1016/S0341-8162(00)00175-2}, url = {/files/bibliography/01-048.pdf}, author = {C. Seybold and Jeffrey E. Herrick} } @conference {51049, title = {Arriving at a scientific concensus in the International Association of Hydrological Sciences (IAHS)}, booktitle = {Fall Meeting}, volume = {82}, number = {47}, year = {2001}, month = {December 10-14, }, pages = {Abstract No. H51E-05}, address = {San Francisco, CA}, abstract = {The International Association of Hydrological Sciences (IAHS) Bureau decided IAHS should become more proactive by focusing on worldwide water problems and developing research programs to address these problems. Particularly, IAHS needs to address global water issues through direct involvement in policy-oriented activities such as those of the World Water Council and World Water Forum 3. IAHS plans to take strong leadership in such programs by demonstrating scientific solutions to problems of hydrologic uncertainty and resulting improvements for water management. IAHS built consensus on a few critical water resources issues and identified the research needed for solutions. First, a unique science discussion was initiated over the Internet. Discussions were first dominated by IAHS officers with responsibilities to promote such discussion, but the it soon spread to individual members and interested people outside IAHS. Many exchanges occurred and numerous areas of research focus were proposed. One proposal that received enthusiastic support was research on ungaged basins. It was accepted as a preliminary IAHS focus because of the need for fundamental research and its relevance to societal needs in all countries. This focus topic was discussed at the 6th Scientific Assembly of IAHS at Maastricht, The Netherlands, in July 2001 during a workshop on the science agenda of IAHS. The participants recommended establishing a working group on prediction of ungaged basins to hold open discussion meetings and workshops to define the appropriate research approaches. A work group on global water assessments was also recommended. The leadership of IAHS has been pleased with the process used and considers this one example of successful consensus building.}, author = {Takeuchi, K. and A. Rango} } @article {JRN54840, title = {Assessing and Monitoring the Health of Western Rangeland Watersheds}, journal = {Environmental Monitoring and Assessment}, volume = {64}, year = {2000}, month = {September 2000}, pages = {153{\textendash}166}, chapter = {153}, abstract = {

The most important function of watersheds in the western U.S. is the capacity to retain soil and water, thereby providing stability in hydrologic head and minimizing stream sediment loads. Long-term soil and water retention varies directly with vegetation cover. Data on ground cover and plant species composition were collected from 129 sites in the Rio Grande drainage of south-central New Mexico. This area was previously assessed by classification of Advanced Very High Resolution Radiometry (AVHRR) imagery. The classification of irreversibly degraded sites failed to identify most of the severely degraded sites based on size of bare patches and 35\% of the sites classified as degraded were healthy based on mean bare patch size and vegetation cover. Previous research showed that an index of unvegetated soil (bare patch size and percent of ground without vegetative cover) was the most robust indicator of the soil and water retention function. Although the regression of mean bare patch size on percent bare ground was significant (p \< 0.001), percent bare ground accounted for only 11\% of the variability in bare patch size. Therefore bare patch size cannot be estimated from data on percent bare ground derived from remote sensing. At sites with less than 25\% grass cover, and on sites with more than 15\% shrub cover, there were significant relationships between percent bare soil and mean bare patch size (p \< 0.05). Several other indicators of ecosystem health were related to mean bare patch size: perennial plant species richness (r = 0.6, p \< 0.0001), percent cover of increaser species (r = 0.5, p \< 0.0001) and percent cover of forage useable by livestock (r = 0.62, p \< 0.0001). There was no relationship between bare patch size and cover of species that are toxic to livestock. In order to assess the ability of western rangeland watersheds to retain soil and water using remote sensing, it will be necessary to detect and estimate sizes of bare patches ranging between at least 0.5 m in diameter to several meters in diameter.

}, keywords = {bare patch size, grass, percent bare soil, remote sensing, shrub, Soil and water retention}, doi = {10.1007/978-94-011-4343-1_14}, url = {/files/bibliography/00-765.pdf}, author = {A.G. de Soyza and Walter G. Whitford and S.J. Turner and Justin Van Zee and A. R. Johnson} } @article {51098, title = {Ant (Hymenoptera: Formicidae) responses to environmental stressors in the northern Chihuahuan Desert}, journal = {Community and Ecosystem Ecology}, volume = {29}, number = {2}, year = {2000}, month = {April 1, 2000}, pages = {200-206}, abstract = {

We studied responses of ant communities to shrub removal and intense, pulse seasonal grazing by domestic livestock for four consecutive years. Weighted relative abundance and percent of traps in which an ant species occurred were analyzed using randomized, complete block design split in time analysis of variance to test for significant differences between means of ant groups. The ant community in the Chihuahuan Desert grassland is dominated by small, liquid-feeding ants, Conomyrma insana (Buckley), and large seed harvesting ants, Pogonomyrmex desertorum (Wheeler). The weighted relative abundance of C. insana was significantly reduced on the plots without shrubs. The relative abundance of P. desertorum was significantly lower on grazed plots without shrubs than on the ungrazed plots without shrubs. There were no detectable effects of shrub removal or intense, pulse grazing on the less abundant ant species. These results suggest the recent encroachment of shrubs into Chihuahuan Desert grasslands has increased the relative abundance of the dominant ant species in these communities. Intensive grazing by livestock has had an adverse effect on the most abundant seed-harvester, P. desertorum.

}, keywords = {ant, Chihuahuan Desert, environmental stressors, Hymenoptera: Formicidae, pulse grazing, shrub removal}, doi = {10.1093/ee/29.2.200}, url = {files/bibliography/00-007_0.pdf}, author = {M. S. Nash and Walter G. Whitford and Justin Van Zee and Kris Havstad} } @conference {51116, title = {ASTER observations over New Mexico test sites}, booktitle = {Fall Meeting, American Geophysical Union}, volume = {81}, number = {48}, year = {2000}, note = {Fall Meeting Supplement; entered in ARIS at Beltsville}, month = {December 15-19, }, pages = {Abstract No. H22E-12}, address = {San Francisco, CA}, abstract = {In June and September 2000, the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) on the Terra satellite obtained data over several test sites along the Rio Grande river in New Mexico. ASTER has 14 channels from the VNIR through the TIR with 15 m resolution in VNIR and 90 m in the thermal. The multispectral TIR data from ASTER provides the opportunity to separate the temperature and emissivity effects observed in the thermal emission from the land surface. The sites include the Sevilleta and Bosque del Apache National Wildlife Refuges, the Elephant Butte reservoir and the Jornada Experimental Range. Ground measurements during these overflights included surface temperature, vegetation type and condition and surface flux measurements. There was also an aircraft flight with the MODIS/ASTER simulator on June 14, 2000, unfortunately not coincident with a satellite overpass. Preliminary results indicate good agreement between ASTER brightness temperatures and ground measures at the reservoir. Analysis of earlier aircraft data have show that the multispectral TIR data are very effective for estimating both the surface temperature and emissivity. These results will be compared with the ASTER data.}, keywords = {ASTER, miltispectral data, MODIS, observations, satellite}, author = {T. J. Schmugge and M. Chopping and A.N. French and Kris Havstad and A. Rango and Jerry Ritchie and Schieldge, J.} } @article {51128, title = {Arroyo water storage and soil nutrients and their effects on gas-exchange of shrub species in the northern Chihuahuan Desert}, journal = {Journal of Arid Environments}, volume = {43}, number = {1}, year = {1999}, month = {1999}, pages = {21-33}, abstract = {

A variable fraction of the rain falling on desert landscapes runs off and accumulates in ephemeral channels (arroyos), where some of the water is transported downslope. Relatively large amounts of water are stored in arroyo sediments. This water may support high rates of gas-exchange in some riparian species. We examined differences in the timing of flow events, soil water storage, and soil nutrients on gas-exchange rates of shrubs growing on arroyo margins and in adjacent piedmont areas in the Chihuahuan Desert of southern New Mexico, USA. The semi-riparian shrub, Fallugia paradoxa (Apache plume), had very different photosynthetic rates between two arroyos, but transpiration rates did not differ. This may result from nutrient limitation differences between arroyos. At one site, the semi-riparian shrub, Prosopis glandulosa (mesquite), on arroyo margins had access to more water and showed higher rates of gas-exchange compared with non-arroyo mesquite located on nearby piedmont areas. The obligate riparian shrub, Chilopsis linearis (desert willow), had intermediate gas-exchange rates when compared with Apache plume and mesquite, and neither soil water nor nutrient concentrations appeared to affect photosynthesis during the growing season. Variation between and within arroyos was high; however, our data suggest that stored water enabled mesquite of arroyo margins to maintain relatively high rates of gas-exchange. When water was relatively abundant, nutrient availability appeared to limit photosynthetic rates of Apache plume. (C) 1999 Academic Press.

}, keywords = {Chihuahuan Desert, Chilopsis linearis, fallugia paradoxa, photosynthesis, prosopis glandulosa, soil nutrients, soil water storage, transpiration}, doi = {10.1006/jare.1999.0530}, url = {/files/bibliography/643.pdf}, author = {Atchley, M.C. and A.G. de Soyza and Walter G. Whitford} } @article {51141, title = {Applying satellite imagery to triage assessment of ecosystem health}, journal = {Environmental Monitoring and Assessment}, volume = {54}, year = {1999}, month = {1999}, pages = {205-227}, abstract = {

Considerable evidence documents that certain changes in vegetation and soil result in irreversibly degraded rangeland ecosystems. We used Advanced Very High Resolution Radiometer (AVHRR) imagery to develop calibration patterns of change in the Normalized Difference Vegetation Index (NDVI) over the growing season for selected sites for which we had ground data and historical data characterizing these sites as irreversibly degraded. We used the NDVI curves for these training sites to classify and map the irreversibly degraded rangelands in southern New Mexico. We composited images into four year blocks: 1988-1991, 1989-1992, and 1990-1993. The overlap in pixel classified as irreversibly degraded ranged from 42.6\% to 84.3\% in year block comparisons. Quantitative data on vegetation composition and cover were collected at 13 sites within a small portions of the study area. Wide coverage reconnaissance of boundaries between vegetation types was also conducted for comparisons with year block maps. The year block 1988-1991 provided the most accurate delineation of degraded areas. The rangelands of southern New Mexico experienced above average precipitation from 1990-1993. The above average precipitation resulted in spatial variable productivity of ephemeral weedy plants on the training sites and degraded rangelands which resulted in much smaller areas classified as irreversibly degraded. We selected imagery for a single year, 1989, which was characterized by the absence of spring annual plant production in order to eliminate the confounding effect of reflectance from annual weeds. That image analysis classified more than 20\% of the rangelands as irreversibly degraded because areas with shrub-grass mosaic were included in the degraded classification. The single year image included more than double the area classified as irreversibly degraded by the year blocks. AVHRR imagery can be used to make triage assessment of irreversibly degraded rangeland but such assessment requires understanding productivity patterns and variability across the landscapes of the region and careful selection of the years from which imagery is chosen.

}, doi = {10.1023/A:1005876220078}, url = {/files/bibliography/652.pdf}, author = {M.D. Eve and Walter G. Whitford and Kris Havstad} } @conference {51190, title = {Activity and volatile constituents of crude fractions of Flourensia cernua (L)}, booktitle = {218th American Chemical Society National Meeting}, year = {1999}, month = {August 22-26, 19}, pages = {Abstract p. 45}, address = {New Orleans, LA}, abstract = {

Crude fractionation of tarbush (Flourensia cernua) was performed by extracting successively with hexanes, diethylether, and ethanol, 35 Kg of leaves in approximately 7 Kg batches. Volatiles from these fractions were examined and the relevance of these findings discussed in relation to palatability studies. The hexane fraction was found to contain most of the monoterpenes while sesquiterpenes made up most of the ethanol fraction. The crude fractions were further submitted to fungal, algal, and termite bioassays. The ether fraction shows the highest activity against fungi. The hexane fraction shows selective activity against the cyanobacterium responsible for methylisoborneol induced off-flavor problem in catfish farming operations. All three fractions show a high degree of antitermite activity.

}, keywords = {activity, Flourensia cernua (L), volatile constituents}, author = {M.R. Tellez and Schrader, K. and Wedge, D.E. and Duke, S.O. and Richard E. Estell and E.L. Fredrickson and Powell, J.E.} } @article {51198, title = {Ants as indicators of exposure to environmental stressors in North American desert grasslands}, journal = {Environmental Monitoring and Assessment}, volume = {54}, year = {1999}, month = {1999}, pages = {143-171}, abstract = {

The relative abundance of ant species was measured by pit-fall trapping at 44 sites in southern New Mexico and southeastern Arizona, U.S.A.. Sites were selected for study based on documentation of a history of disturbance or protection from disturbance, exposure to varying intensities of livestock grazing, dominance by an exotic species of plant and vegetation change resulting from disturbance or restoration efforts. Ant community composition, relative abundance of species, and species richness were the same on disturbed and undistrubed sites. None of the metrics based on hypothesized responses of ants to disturbance clearly distinguished between disturbed and undisturbed sites. Ant communities on sites where restoration efforts have resulted in distinct differences in vegetative cover and composition were similar to the ant communities on degraded unrehabilitated sites on the same soil type. Ant communities in riparian cottonwood gallery forests in Arizona and New Mexico were similaar but differed from the assemblages in exotic salt cedar and native ash riparian woodlands. Ant species exhibited remarkable resistance to human-induced disturbance in these rangeland areas. In grasslands dominated by the South African grass, Eragrostis lehmanniana Nees, large seed harvesting ants, Pogonomyrmex spp., were greatly reduced in abundance compared to native grasslands. Other ants metrics were not different in E. lehmanniana grasslands and native grasslands. We conclude that ants cannot be used as indicators of exposure to stress, ecosystem health or of rehabilitation success on rangeland ecosystems. Ants are also not useful indicators of faunal biodiversity in rangeland ecosystems.

}, keywords = {environmental stressors, exposure indicators}, doi = {10.1023/A:1005858918860}, url = {/files/bibliography/535.pdf}, author = {Walter G. Whitford and Justin Van Zee and M. S. Nash and W. E. Smith and Jeffrey E. Herrick} } @inbook {51231, title = {Application of an individual-based model for sand grasslands in Hungary}, booktitle = {Advances in Community Ecology}, year = {1998}, month = {1998}, pages = {197-207}, publisher = {Scientia Publishing}, organization = {Scientia Publishing}, address = {Budapest, Hungary}, abstract = {

Individual plant-based gap dynamics models have been used extensively in forests and less frequently in grasslands. In this chapter, we summarize the use of these models in different ecosystem types and describe the application of one of these models, ECOTONE, to simulating sand grasslands in Hungary. The structure of ECOTONE is similar to forest models in that the recruitment, growth, and mortality of individual plants are simulated on a small plot through time at an annual time step. Recruitment and mortality have stochastic elements whereas growth is deterministic and dependent upon competition for soil water. ECOTONE was parameterized for sand grasslands in Hungary using data available from the literature. Various possibilities for including heterogeneity in vegetation at the landscape scale are discussed. These possibilities include averaging results from many plots, adding variation to input parameters, conducting simulations for different landscape patches, and conducting spatially- explicit simulations. A major strength of simulation modeling is that it complements field studies and contributes to new studies by generating testable hypotheses.

}, url = {/files/bibliography/625.pdf}, author = {G. Kroel-Dulay and Debra C. Peters}, editor = {Fekete, G.} } @inbook {51233, title = {Application of mechanistic simulation models in predicting the impact of climate change on the dynamics of sand grasslands}, booktitle = {Climate change and its impacts}, year = {1998}, month = {1998}, pages = {137-146}, publisher = {OMSZ}, organization = {OMSZ}, address = {Budapest, Hungary}, abstract = {

We used two simulation models to examine the importance of directional changes in climate to the dynamics of sand grasslands in Hungary. We used an individual plant-based model (ECOTONE) to evaluate the effects of climate change on aboveground biomass of three sand grasslands located along an aridity gradient. Increases in temperature led to a small increase ein biomass whereas decreases in precipitation led to decreases in biomass. None of the climate scenarios resulted in shifts in dominance between Stipa and Festuca species. A small difference in climate between the two wetter, cooler sites resulted in a much larger difference in biomass. Because these differences are not observed in the field, other processes that may be affected by climate change, such as seedling establishment, may be important. We also used a daily time step soil water model (SOILWAT) to examine the effects of directional changes in climate on site water balance. We found that the same amount of precipitation is used more effectively by plants if it comes in fewer big events compared to many small events. Consequently, a dry year has severe effects on plant growth both due to small amounts as well as to the distribution of rainfall events since most events are small and less effective. Furthermore, if changes in climate shift to a decrease in precipitation, there may also be a shift in the distribution of rain events to small events that will have a disproportionate effect on the vegetation.

}, url = {/files/bibliography/622.pdf}, author = {G. Kroel-Dulay and Bartha, S. and Wantuchne, D.I. and Kovacs-Lang, E. and Debra C. Peters}, editor = {Dunkel, Z.} } @proceedings {51235, title = {Application of Monin-Obukhov similarity over a mesquite dune site in the Jornada Experimental Range}, year = {1998}, month = {11/1998}, pages = {216-219}, publisher = {American Meteorological Society}, abstract = {

Monin-Obukhov similarity (MOS) theory has been a widely applied approach for estimating turbulent fluxes of heat and momentum in the surface layer and is used exclusively by Soil-Vegetation-Atmosphere-Transfer (SVAT) models for simulating surface-atmosphere process. However, a number of studies have shown significant discrepancies between turbulent fluxes derived from MOS and measured directly by eddy covariance for rough and heterogeneous surfaces (e.g., Chen and Schwerdtfeger, 1989).

In this paper, we discuss the applications of MOS using mean profiles of temperature, 0, and wind speed, u, for estimating sensible heat and momentum fluxes over a mesquite dune site in the USDA-ARS Jornada Experimental Range near Las Cruces, New Mexico. The site contains complex topography and heterogeneous cover where 0.5 m tall mesquite vegetation grow on dunes that are 1-2 m in height and ~10 m in width. Distances between dunes are on the order of 20 m. Very little if any vegetation exists in this interspace region.

}, keywords = {Jornada Experimental Range, mesquite dune site, Monin-Obukhov}, url = {files/bibliography/Rango1998-02.pdf}, author = {William P. Kustas and J.H. Prueger and Lawrence E. Hipps and K. Ramalingam and J. Hatfield and T. J. Schmugge and A. Rango and Jerry Ritchie and Kris Havstad} } @article {51242, title = {AIRSAR studies of woody shrub density in semiarid rangeland: Jornada del Muerto, New Mexico}, journal = {Remote Sensing of Environment}, volume = {66}, year = {1998}, note = {//NMSU, USDA//LTER III//}, month = {1998}, pages = {29-40}, abstract = {

This study evaluates the use of polarimetric Airborne Synthetic Aperture Radar (AIRSAR) data to assess woody shrub density in a semiarid site where the vegetation consists primarily of varied mixtures of herbaceous vegetation and shrubs. AIRSAR data and field observations of vegetation cover and growth form-composition were obtained for 59 sites in the Jornada del Muerto plain in southern New Mexico. Radar signature measures examined were C-, L- and P-band backscattering coefficients (s) for HH, HV and VV polarizations, rations of sHH and sHV to sVV, and the HH-VV polarization phase difference and correlation coefficient. The most effective measure for estimation of shrub density was L-band sHV, which distinguished among shrub density classes with no misclassification. Sensitivity of this measure to small amounts of shrub cover was indicated by successful separation of sites with \<1\% shrub cover from sites with 1-5\% cover. Separability of shrub density classes was generally least for C-band signature measures. A distinctive radar signature was exhibited by dense stands of Yucca elata, a semitreelike plant with uniformly thick ({\guillemotright}10 cm diameter) fibrous stems. Yucca sites were distinguished from others by their high P-band sHV relative to L-band sHV. The results are largely explained by the greater sensitivity of longer wavelengths to larger canopy structural elements. L-band sHV and other measures responsive to canopy volume scattering were more strongly related to shrub than to herbaceous plant cover because woody shrub canopies have numerous stems of the intermediate size to which L-band is most sensitive, whereas stems of this size are mostly lacking in herbaceous canopies. The uniform-diameter stems of yucca have larger dimensions to which P-band is more sensitive than L-band. {\textcopyright}Elsevier Science Inc., 1998

}, keywords = {article, articles, journal, journals, remote sensing, AIRSAR, shrub encroachment}, doi = {10.1016/S0034-4257(98)00033-9}, url = {files/bibliography/JRN00252.pdf}, author = {Musick, H. Brad and Schaber, Gerald G. and Breed, Carol S.} } @conference {51254, title = {Assessment of soil and vegetation resource redistribution 20 years after the construction of a Chihuahuan Desert water catchment}, booktitle = {51st Annual Meeting, Society for Range Management}, volume = {51}, year = {1998}, month = {1998}, pages = {Abstract 56}, abstract = {

Patches generating water runoff are common in desert environments, resulting in loss of critical resources in arid systems. It becomes necessary to reduce the loss of resources in these systems to increase diversity and productivity. In 1975, five water catchment dikes were constructed on an area that was devoid of vegetation. The area is near the basin floor of the Jornada del Muerto where a physical soil crust forms under the impact of precipitation. This landscape was below a critical threshold level where the soil resources could support plant growth. The objectives of the study were to measure the establishment and persistence of seeded and native species, to examine the spatial distribution of seeds, and to measure soil physical characteristics over the area containing the water catchment dikes. Plant community samples, seed bank samples and soil samples for physical and chemical analysis were collected in the summer of 1997. All data was analyzed using geostatistical analysis. Correlations between distance to catchment dike and changes in plant community composition, seed bank distribution and soil physical characteristics were apparent. Vegetation, seed bank and soil resources were concentrated nearest to the catchment dikes. The construction of the catchment dikes on an area formerly devoid of vegetation appears to be successful and sustainable over a period of 20 years.

}, author = {Walton, M. and Jeffrey E. Herrick and Gibbens, Robert P.} } @article {JRN54841, title = {Assessment of a method for mapping woody plant density in a grassland matrix}, journal = {Journal of Arid Environments}, volume = {38}, year = {1998}, month = {February 1998}, pages = {269-282}, chapter = {269}, abstract = {

Determining patterns of land degradation, and by inference the ecological processes at play, is critical to designing and implementing strategies and tactics to halt degrading practices and restore already degraded areas. In this paper we describe the application of a new image analysis technique to determine the presence and density of shrubs in a grassland matrix and evaluate its use for assessing rates and patterns of shrub increase, a common form of land degradation in rangelands throughout the world. By analysing a series of images derived from aerial photography to identify and separate objects (shrubs) in progressive steps, we were able to detect accurately individual shrubs with canopies greater than 9\ m2(about 85\% of the sample population). The method also was moderately successful in predicting canopy area of individual trees. This approach offers land managers and policy-makers a tool for defining both temporal patterns and rates of shrub increase as well as for defining the current extent of an invasion as a basis for targeting control technologies.

}, keywords = {aerial photography, density slicing, Geographic Information System, image analysis, remote sensing, shrub invasion}, doi = {10.1006/jare.1997.0325}, url = {/files/bibliography/770.pdf}, author = {Grant Whiteman and Joel R. Brown} } @proceedings {51271, title = {Aerodynamic roughness estimated from surface features for a coppice dune area using laser altimeter data}, year = {1997}, note = {//USDA//LTER III//ProCite field[6]: In}, month = {July 28 - August}, pages = {289-292}, address = {Vancouver, BC, Canada}, abstract = {This paper evaluates the use of high resolution laser altimeter data for estimating the effective aerodynamic roughness in a coppice dune area. In this landscape the total drag is primarily due to the large scale obstacles with a secondary contribution of the interdunal areas. For the area under study, wind profiles were available up to a height of 10 meters, accounting for a fetch of approximately 100 m. Menenti and Ritchie (1994) evaluated the use of laser altimeter data for calculating the aerodynamic roughness for the local scale. The current paper extends their research and derives the effective roughness including local topography.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, JORNEX, remote sensing, proceeding, proceedings, remote sensing, aerodynamic roughness, remote sensing, coppice dunes, remote sensing, JORNEX, remote sensing, laser altimetry, remote sensing, surface roughness}, author = {De Vries, A. C. and Jerry Ritchie and Menenti, M. and William P. Kustas} } @conference {51282, title = {Assessing and monitoring the quality of rangeland soils: Early warning indicators of desertification}, booktitle = {International Symposium and Workshop Combating Desertification: Connecting Science with Community Action}, year = {1997}, month = {May 12-16, 1997}, pages = {Abstract 32}, address = {Tucson, AZ}, abstract = {Soil quality can be defined as the soil{\textquoteright}s capacity to perform selected functions, resist degradation, and recover after disturbance. Soil quality depends upon interactions between soil, soil microflora and fauna, and vegetation. Direct and indirect measures of these interactions may therefore serve as useful indicators of overall ecosystem condition. We examined several indicators of soil quality on grazing intensity gradients, exclosed as grazed plots, degration sequence plots, and plots subjected to ecosystem reconstruction. Indicators examined include penetrometer resistance, final infiltration rate, soil surface stability (resistance to slacking), soil surface properties, obstruction value of vegetation, and soil texture. Other soil properties examined include abundance of soil microarthropods and activity of organisms that cause soil turnover. We present approaches for calibrating data and linking data to ecosystem processes and an approach for combining indicators of soil quality for a variety of management objectives.}, author = {Jeffrey E. Herrick and Walter G. Whitford} } @conference {51295, title = {Annual plant vegetation boundaries on disturbance gradients in Chihuahuan Desert rangelands}, booktitle = {International Symposium and Workshop Combating Desertification: Connecting Science with Community Action}, year = {1997}, month = {May 12-16, 1997}, pages = {Abstract 21}, address = {Tucson, AZ}, url = {/files/bibliography/592.pdf}, author = {M. S. Nash and Walter G. Whitford} } @article {51297, title = {Analysis of desert plant community growth patterns with high temporal resolution satellite spectra}, journal = {Journal of Applied Ecology}, volume = {34}, year = {1997}, month = {1997}, pages = {418-432}, abstract = {
1.The study of a desert landscape consisting of C3 shrublands and C4 grasslands demonstrated the feasibility of mapping desertification processes on a regional scale using time-series satellite images, and demonstrated the potential for monitoring desertification processes through time. 2.Fifteen meteorological satellite images of southern New Mexico, spread over the growing season of 1989, were processed to yield images of normalized difference vegetation indices. Computer classification of these images and comparison with extensive ground measurements confirmed the identification of the major classes of shrubland, grassland and mixed shrub and grass areas. 3.Our high-resolution temporal approach is shown to permit the accurate identification of vegetation types even under conditions of sparse vegetation cover. The phenologies of grassland and shrubland were revealed in the time series of satellite images. We used this feature of lite data to overcome the tendency of the strong radiation signal from bare soil to mask the biomass signal. 4.Comprehensive comparisons with ground measurements confirmed the accuracy of the biomass identification for local areas within the Jornada Experimental Range, and justified extrapolation of the classification to a larger adjacent area.
}, keywords = {Chihuahan Desert, phenology, satellite imagery, vegetation index}, doi = {10.2307/2404887 }, url = {/files/bibliography/593.pdf}, author = {Peters, A.J. and M.D. Eve and Holt, E.H. and Walter G. Whitford} } @article {51333, title = {Ancient soils of the Rincon surface, northern Dona Ana County}, year = {1996}, note = {//LOCAL//LTER III//ProCite field[12]: In File (01/10/2005)}, month = {1996}, pages = {155}, institution = {USDA Natural Resources Conservation Service}, type = {pp}, address = {National Soil Survey Center, Lincoln, NE}, abstract = {Volume II of the Supplement to the Desert Project Soil Monograph is the second of a number of reports on soils in the Desert Project area. Volume II consists of two chapters, of which the first is a detailed study of a remnant of the Rincon surface and its soils. The Rincon surface is a remnant of one of the oldest basin landscapes in North America, and probably dates from late Pliocene time or earlier. The remnant consists of an ancient basin floor and an adjacent alluvial-fan piedmont, preserved in a bedrock-defended area 600 feet above the Rio Grande flood plain. Chapter 2 focuses on clay mineralogy of the Desert Project and the Rincon study area. It describes clay mineralogy as a function of age, parent material, and depth. It also compiles the narrative clay mineralogy information produced during the period from 1957 to 1972.}, keywords = {book, books, chapter, chapters, landscape, evolution, report, reports, Rincon, soil, Desert Project, soil, development}, isbn = {Soil Survey Investigations Report $\#$44}, author = {L. H. Gile and R. Grossman and J. Hawley and Curtis H. Monger}, editor = {L. H. Gile and R. J. eds. Ahrens} } @conference {51347, title = {Application of soil quality assessments to rangeland remediation and sustainable management}, booktitle = {Workshop on Long-Term Research on Soil, Water, and Nutrient Management within the CGIAR System}, year = {1996}, month = {July 26-27, 1996}, address = {Columbus, OH}, keywords = {assessments, rangeland, remediation, soil quality, sustainable management}, author = {Jeffrey E. Herrick} } @conference {51352, title = {Application of the desertification response unit methodology to multi-scale assessments of rangeland soil quality}, booktitle = {American Society of Agronomy Meeting}, year = {1996}, month = {November 3-7, 19}, pages = {Abstract 224}, address = {Indianapolis, IN}, abstract = {Soil quality can be defined in terms of three sets of variables which are related to: (1) functional integrity, (2) resistance to disturbance, or inertia, and (3) resilience, or the capacity of the soil to recover functional integrity following disturbance. Functional integrity, resistance, and resilience all vary as a function of processes which vary at different spatial scales; assessment of all three can be improved by accounting for this spatial variability and scale. However, few sampling and analysis approaches for assessing soil quality currently utilize spatial information. The Desertification Response Unit (DRU) methodology was developed in Europe as part of an effort to model processes of land degradation and desertification. The DRU methodology emphasizes landscape position and the potential for interactions and linkages between units at different spatial and temporal scales. It is based on assessing key processes operating at scales ranging from the patch or micro-site to the watershed, and combines static site characteristics at each scale with land surface and vegetation patterns to yield estimates of system resistance and resilience. A preliminary application of the methodology to the assessment of soil quality in rangeland ecosystems for SE Spain suggests that (1) sampling points should be selected to represent key landscape positions within watersheds, (2) measurements should be stratified by cover type, and (3) small-scale changes in soil quality are reflected in long-term dynamics at larger scales.}, author = {Imeson, A.C. and Jeffrey E. Herrick and Kris Havstad} } @article {51371, title = {Arthropod associates and herbivory on tarbush in southern New Mexico}, journal = {The Southwestern Naturalist}, volume = {41}, number = {2}, year = {1996}, note = {//USDA//LTER-III//}, month = {1996}, pages = {140-144}, abstract = {

Arthropod abundances, seasonality, and defoliation were measured on tarbush (Flourensia cernua) in southern New Mexico during 1990 and 1991. The arthropod assemblage on this desert shrub was dominated by five species of sap-sucking herbivores, four species of chewing herbivores, two ants, parasitic Hymenoptera, and two spider families. Species richness and abundances were highest during late summer. Several taxa present in substantial numbers at budburst in spring may overwinter on, or rapidly discover, this resource. Defoliation was caused primarily by a chrysomelid beetle (Zygogramma tortuosa) and amounted to about 30\% by late summer. The arthropod functional group organization (e.g., proportions of chewing and sap-sucking herbivores, predators and detritivores) on tarbush is similar to that measured on other shrub species using comparable techniques.

}, keywords = {arthropod, abundances, arthropod, defoliation, article, articles, Flourensia, arthropod assemblage, Flourensia, defoliation, journal, journals, shrub defoliation, arthropods}, url = {files/bibliography/JRN00202.pdf}, author = {Schowalter, T. D.} } @article {51401, title = {Assessing the quality of rangeland soils: Challenges and opportunities}, journal = {Journal of Soil and Water Conservation}, volume = {50}, number = {3}, year = {1995}, month = {1995}, pages = {237-242}, abstract = {

Rangeland soils present unique challenges and opportunities for assessing soil quality. Three characteristics in particular distinguish rangeland soils from cropped soils: (l) spatial variability in rangelands rends to be higher than in cropped systems; (2) temporal variability is high because many biological and physical processes depend on a limited and frequently unpredictable supply of soil moisture; (3) the land often has many uses in addition to food production.

}, url = {/files/bibliography/453.pdf}, author = {Jeffrey E. Herrick and Walter G. Whitford} } @inbook {51404, title = {Arid and semi-arid lands}, booktitle = {Global Biodiversity Assessment}, year = {1995}, note = {//OTHER//LTER III//}, month = {1995}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, address = {Cambridge}, keywords = {biodiversity, water, book, books, chapter, chapters, report, reports, water, biodiversity}, author = {L. Huenneke and I. R. Noble}, editor = {V. H. Heywood} } @article {51419, title = {Application of GIS and remote sensing for resource management in the northern Chihuahuan Desert}, year = {1995}, note = {//NMSU, USDA//LTER III//ProCite field[2]: 17 graduate students advised by Dr. Frank Scarpace, with assistance from Dr. Mark MacKenzie, Ms. Nancy Podger and Mr. Raad Saleh}, month = {9 June 1995}, pages = {204}, type = {pp}, abstract = {

The main objective of this two-semester Practicum was to evaluate the utility of geographic information systems (GIS) and remote sensing methodologies for resource management in the northern Chihuahuan Desert. Feature detection and image classification were particularly emphasized. This report is intended as a reference for managers needing to monitor and accurately assess change over spatial extents too large for traditional inventory methods. Such large area land characterization is well suited for the generation of predictive models focused on the impacts of land use, the detection of archaeological resources, and the study of the changing nature of regional landscapes. This report provides detailed evaluation of methodologies designed for monitoring the resources of the northern Chihuahuan Desert. Four study sites have been chosen as representative of the larger region. these areas were chosen because of the wide diversity of land cover and distinctive land use histories that are felt to integrate many of the patterns and processes within the northern Chihuahuan region. three sites are within the United States Army\&$\#$39;s Fort Bliss installation, located in El Paso County in western Texas, and Doa Ana and Otero Counties in south-central New Mexico, and the fourth location is a subset of the Jornada-LTER site which is 37 km north of Las Cruces.

}, keywords = {book, books, chapter, chapters, GIS, management, remote sensing, remote sensing, report, reports}, isbn = {1994-1995 IES Environmental Monitoring Practicum, Environmental Monitoring Graduate Degree Program, University of Wisconsin}, author = {Scarpace, Frank L. and Matthew Bobo and Cardille, Jeffrey A. and Carlson, Jeffrey Dean and Chipman, Jonathan Ward and Cochrane, Kenneth Carl and Fassnacht, Karin S. and Hagemann, Estefania B. V. and Harring, Linda Ann and Hirth, Resse Edward and Jennings, Nathan P. and Hee-Bum Lee and Maggio, Patricia Louise and McCormick, Ronald Joseph and Pope, Paul Albert and Roffers, Peter Daniel and Sherman, Benjamin Harrison and Walkey, John Andrew} } @article {51448, title = {Animal unit equivalents: An examination of the sheep to cattle ratio for stocking rangelands}, year = {1994}, month = {February 1994}, pages = {14 }, abstract = {

Efforts to properly manage forage resources on our nation{\textquoteright}s rangelands led to development of the ideas: "carrying capacity" and "stocking rate." Carrying capacity refers to how many and how long livestock can be placed on an area of land without damaging the ecosystem. Stocking rate is the density of livestock (animalsIacre) for a given unit of time, and is generally determined by management objectives and estimates of carrying capacity. Because several species and types of grazing animals are used by livestock producers, attempts have been made to develop a standardized animal unit so that differences in forage demand across animal physiological classes and among species could be expressed on a common basis. A mature nonlactating 1100 lb beef cow is an animal unit. Ratios of other species and classes compared with an animal unit are called animal unit equivalents (AUE{\textquoteright}s). Animal units are currently used as a basis for grazing fee assessments on private and public lands, and for economic assessments such as appraised value of a ranch or its loan value. Due to the possibility of increasing costs charged by Federal and State agencies for an animal unit, there is a need to examine animal unit equivalents for accuracy so parity can be ensured. This paper will examine the development of AUE{\textquoteright}s for sheep and suggest a change to the current system.

}, url = {/files/bibliography/426.pdf}, author = {Kris Havstad and E.L. Fredrickson and Richard E. Estell} } @conference {51453, title = {Approaches to assessing the quality of rangeland soils}, booktitle = {American Society of Agronomy Meeting}, year = {1994}, month = {November 13-18, }, pages = {Abstract 285}, abstract = {Soil quality can be defined as the soil{\textquoteright}s capacity to perform selected functions, to resist degradation, and to recover following disturbance. It depends on interactions between the soil, soil fauna, and vegetation, and, therefore, may serve as a useful integrated indicator of overall ecosystem condition. Definitions of ecosystem condition, however, depend on management objectives. We will present an approach for calibrating indicators of semiarid rangeland soil quality for a variety of management objectives. This integrated approach will be illustrated with preliminary data from a study of semiarid rangeland in the Chihuahuan Desert. These data, together with other recent studies, suggest that spatial patterns may be as useful as average values of soil properties in assessing soil quality for noncultivated systems.}, keywords = {assessing quality, Chihuahuan Desert, rangeland soils}, author = {Jeffrey E. Herrick and Walter G. Whitford} } @article {JRN54651, title = {Areal extent of seasonal snow cover in a changed climate}, journal = {Nordic Hydrology}, volume = {25}, year = {1994}, month = {August 1994}, pages = {233-246}, abstract = {

In mountain snow basins, a change in climate will likely cause a change in the basin snow cover extent. A procedure for evaluating whether a given climate change scenario will speed up or slow down the seasonal decrease of snow covered area is outlined with hypothetical examples for a simple basin. This procedure has two main purposes. First, it can be used to generate snow covered area data in a new climate for input to runoff models such as the Snowmelt-Runoff Model (SRM). Second, it could potentially be used to provide input to climate models that require knowledge of the land area covered by snow at a given time. A computer program is now operational for use on real basins and is demonstrated on the Rio Grande basin in Colorado and the Illecillewaet River basin in British Columbia.

}, url = {/files/bibliography/94-001.pdf}, author = {A. Rango and J. Martinec} } @article {51475, title = {Assessing the relationship between spectral vegetation indices and shrub cover in the Jornada Basin, New Mexico}, journal = {International Journal of Remote Sensing}, volume = {14}, number = {18}, year = {1993}, note = {//USDA, NMSU//LTER II//}, month = {1993}, pages = {3395-3416}, abstract = {

We assessed the statistical relations between spectral vegetation indices (SVIs) derived from SPOT multi-spectral data and semi-arid shrub cover at the Jornada LTER site in New Mexico. Despite a limited range of shrub cover in the sample the analyses resulted in r2 values as high as 0.77. Greenness SVIs (e.g., Simple Ratio, NDVI, SAVI, PVI and an orthogonal Greenness index) were shown to be more sensitive to shrub type and phenology than brightness SVIs (e.g., green, red and near -infrared reflectances and a Brightness index). The results varied substantially with small-scale changes in plot size (60m by 60m to 100m by 100m) as a consequence of landscape heterogeneity. The results also indicated the potential for the spectral differentiation of shrub types, and shrubs from grass, using multi-temporal, multi-spectral analysis.

}, keywords = {article, articles, journal, journals, plant, spectral vegetation indices, Flourensia, plant, spectral vegetation indices, Larrea, plant, spectral vegetation indices, Prosopis, remote sensing, shrub cover, remote sensing, spectral vegetation indices, shrub, spectral vegetation indices}, doi = {10.1080/01431169308904454}, url = {files/bibliography/JRN00165.pdf}, author = {J. Duncan and Douglas Stow and Janet Franklin and Allen Hope} } @conference {51482, title = {Animal and shrub interactions: Developing a tarbush model}, booktitle = {8th Wildland Shrub and Arid Land Restoration Symposium}, year = {1993}, month = {1993}, pages = {Abstract 7}, address = {Las Vegas, NV}, abstract = {Large areas of the Chihuahuan Desert are undergoing a transition from semiarid grassland to desert scrub. The role of mammalian herbivores in mediating this transition has been suggested but has not been adequately described. A better understanding of plant-animal interactions may assist in developing animal-based technologies to increase shrub use while mediating vegetational change. Tarbush (Flourensia cernua), an aromatic shrub rapidly invading productive range sites, was used as a model to examine the influence of leaf surface compounds on the use of tarbush by domestic sheep. Additional studies also were designed to examine the digestive and physiological consequences of ingestion of tarbush leaves. Results from these studies indicate: (1) dietary preference is influenced by either epicuticular waxes or a component of the wax, (2) intraspecific variation of epicuticular chemistry varies both temporally and spatially, (3) nutrient concentrations are similar to alfalfa, (4) ruminal fermentation patterns are altered by inclusion of tarbush in grass diets, and (5) toxicosis can result from chronic consumption of tarbush leaves. Interpretation of these data suggest controlled use of tarbush by sheep is possible, but use of sheep to mediate desired vegetational change may be limited.}, author = {E.L. Fredrickson and Richard E. Estell and Kris Havstad} } @article {51510, title = {An attempt to bond weaned 3-month-old beef heifers to yearling ewes}, journal = {Applied Animal Behavior Science}, volume = {34}, year = {1992}, note = {Reprinted with permission from Elsevier, {\textcopyright} 1992. http://www.sciencedirect.com/science/journal/01681591}, month = {1992}, pages = {181-188}, abstract = {

This study was conducted to determine if weaned younger heifers, averaging three months of age, would bond to sheep. To accomplish reciprocal bonding, 90-day-old heifers were penned for 80 d singly or in groups of three with two or five yearling ewes, respectively. Following 40 d and 80 d of pen confinement, the cattle and sheep were observed together while on pasture and interspecific distances were estimated at 15-min intervals over several consecutive hours. Single heifers followed and consistently stayed very close to sheep. However, if two or more heifers were together at pasture, the heifers would not consistently stay with the sheep. Therefore, the attachment of single heifers to sheep is believed to be due to social dependence. During observations when two or more heifers were together at pasture, the yearling ewes which had been penned together with the heifers usually followed the heifers. Additional observations made during this study suggest that yearling ewes will form an attraction and follow cattle when at pasture after having been penned with them for 80 d.

}, doi = {10.1016/S0168-1591(05)80066-8}, url = {/files/bibliography/378.pdf}, author = {D.M. Anderson and Clarence V. Hulet and J. N. Smith and Shupe, W. Larry and L. W. Murray} } @mastersthesis {51518, title = {Application of GIS technology to hydrologic modeling of patch dynamics on a small, semi-arid watershed in southern New Mexico}, year = {1992}, note = {//NMSU//LTER II//}, month = {1992}, pages = {125}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Studies of infiltration in semi-arid regions indicate large spatial and temporal variations in infiltration rates. Factors which control infiltration such as soil properties, vegetal density, and antecedent soil moisture, are all spatially variable. For the sake of simplicity, formulations of many hydrolic models have traditionally assumed watershed homogeneity and disregarded spatial and temporal variability of such parameters. If watershed response is to be modeled more acccurately, models must account for spatial and temporal variation....The integration of ERDAS and SIMSED was successfully achieved and the system was implemented to show a potential application. A storm event was run at various percentages of existing vegetal cover conditions to observe the incurred changes to runoff and erosion potential. The results indicated very strong negative correlations between vegetal cover and erosion and to a lesser extent runoff.}, keywords = {dissertation, dissertations, hydrology,soil infiltration, model, SIMSED, model,soil infiltration, remote sensing,hydrology, remote sensing,soil infiltration, theses, thesis}, author = {Daggett, Kevin C.} } @article {51520, title = {The application of a geometric optical canopy reflectance model to semiarid shrub vegetation}, journal = {IEEE Transactions on Geoscience and Remote Sensing}, volume = {30}, year = {1992}, note = {//NMSU,USDA//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1992}, pages = {293-301}, abstract = {

The Li-Strahler [7] canopy model was tested, using SPOT HRV XS imagery, for semiarid shrub vegetation, based on 26 small (1-ha) sites in five classes of shrub vegetation, two dominated by tarbush (Flourensia cernua), one by creosote bush (Larrea tridentata), and two by mesquite (Prosopis glandulosa). The model was driven by reflectance values derived from June and September imagery. While predictions of crown size and density for individual sites had a large average error of 35\%, the predictions of shrub size and density were reasonably accurate when grouped by shrub class. The aggregated predictions for a number of stands within a class were accurate to within one or two standard errors of the observed average value. Accuracy was highest but predictions were biased for some classes (size was underestimated) when the nonrandom shrub pattern was characterized for the class based on the average coefficient of determination of density. Results based on June data were not better than September because the hypothesized lower background "noise" (e.g., less green herbaceous cover that could be confused with shrub cover in the simple reflectance model) was not observed in June data. This could have been due to the poor radiometric quality of the June image.

}, keywords = {article, articles, journal, journals, model, shrub canopy reflectance, remote sensing,reflectance model}, doi = {10.1109/36.134079}, url = {files/bibliography/JRN00163.pdf}, author = {Janet Franklin and Turner, Debra L.} } @article {51539, title = {Alkalinity measurements in water extracts of calcareous soils}, journal = {Soil Science Society of America Journal}, volume = {56}, year = {1992}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1992}, pages = {598-600}, abstract = {

In soil carbonate solubility studies, it is usually assumed that total alkalinity is equal to inorganic-C alkalinity. Recent studies have raised questions about the validity of this assumption. This study reexamined previously published soil data from grass-oak (Quercus spp.) woodlands and deserts to test the hypothesis that total alkalinity is equal to inorganic-C alkalinity. Total alkalinity was measured with strong-acid titration, while inorganic-C alkalinity was calculated from pH and the partial pressure of CO2 (pCO2) measurements. Within the limits of error, calculated inorganic C alkalinity (Y) was equal to measured total alkalinity (X) (Y = 0.01 + 0.998X, r2 = 0.97). A recommendation was made for overdetermining the state of experimental systems in solubility studies; this allows one to check the internal consistency of experimental measurements, equilibrium constants, and model assumptions.

}, keywords = {alkalinity, calcareous soil, article, articles, calcareous soil,alkalinity, journal, journals, soil, calcareous}, doi = {10.2136/sssaj1992.03615995005600020042x}, url = {files/bibliography/JRN00150.pdf}, author = {G. M. Marion and W. H. Schlesinger and P. J. Fonteyn} } @article {51558, title = {Ant mound influence on vegetation and soils in a semiarid mountain ecosystem}, journal = {The American Midland Naturalist}, volume = {126}, number = {1}, year = {1991}, note = {//OTHER//NONE//}, month = {1991}, pages = {125-139}, abstract = {

We examined vegetation patterns and soil properties associated with western harvester (Pogonomyrmex occidentalis) mounds in a pinyon-juniper community and a ponderosa pine community near Los Alamos, New Mexico. Plant-clearing habits of the ants exerted a minor influence on total plant cover. Denuded zones (discs) around the mounds in the pinyon-juniper and ponderosa pine sites represented 1.2\% and 1.0\% of the total surface area and reduced plant cover 0.35\% and 0.49\%, respectively. Vegetation near the perimeter of the cleared discs had decreased species richness and lowered percent cover compared with adjacent reference areas (sampled 3.0 m from discs). Comparisons of plant species occurrences around the discs revealed that (1) most species, including dominant understory plants, were evenly dispersed in relation to nest discs; (2) two species - one in each site - were significantly associated with areas near discs; and (3) six species - four in the pinyon-juniper site and two in the ponderosa pine site - were significantly associated with reference areas. Analysis of vegetation on abandoned mounds suggested that seed predation by the ants influences patterns of plant species occurrence adjacent to nests. Active mounds in the pinyon-juniper and ponderosa pine sites occured at densities of 17/ha and 14/ha and had an average mass of 38 kg and 48 kg, respectively. Particle size analysis indicated that the ants construct mounds primarily of gravel and sand fractions. Mound soils at both sites had elevated concentrations of NO3, P and K, increased conductivity and lower water content compared with disc and reference soils. Disc soils in both sites had lower organic matter content but were otherwise similar to reference soils. Activities of P. occidentalis cause localized accumulations of nutrients that are unavailable to plants until mound abandonment. Colony influences on vegetation patterns beyond the denuded discs and lingering effects of abondoned mounds contribute to plant community heterogeneity.

}, keywords = {ant nest, soil nutrients, ant nest, soil properties, ant nest, vegetation, ant, Pogonomyrmex, article, articles, journal, journals, Pogonomyrmex, nest properties, vegetation, ant nest}, doi = {10.2307/2426157 }, url = {files/bibliography/91-AmMidlndNaturalist-Whitford.pdf}, author = {Carlson, S. R. and Walter G. Whitford} } @mastersthesis {51579, title = {Associations of annual plants and shrubs in the northern Chihuahuan Desert}, year = {1991}, note = {//NMSU, USDA//NONE, LTER//Abstract only//ProCite field[36]: Located in}, month = {1991}, pages = {75}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = { The Chihuahuan Desert in North America consists of semi-arid grassland and shrubland communities. Dominant shrubs in the northern part of the Chihuahuan Desert include Prosopis glandulosa, Larrea tridentata, and Flourensia cernua. The objectives of this research were to examine associations of winter and summer annual plants with three dominant shrub species (Larrea tridentata, Prosopis glandulosa, and Flourensia cernua) and to examine differences between patterns of C3 and C4 annual plants. Do annuals tend to be associated with shrubs or are they found more frequently in intershrub spaces? Do winter annuals have stronger associations with shrubs than summer annuals? Is there a pattern of species-specific associations between annuals and the three dominant shrub species in areas where all three shrubs co-occur, controlling for soil differences? If so, do the same patterns of annual-shrub associations exist in areas where single shrub species dominate on potentially different soils? Does a pattern emerge on different soils, indicating that soils rather than properties of the shrubs more strongly determine associations? Is one shrub species "preferred" by any annual plant species over other shrubs, or is the microhabitat provided by any shrub equivalent in accounting for patterns? I sampled annual plants under and near shrubs, on plots codominated by the three shrub species and on plots dominated by single shrub species. I then used statistical methods to test for associations between annual plants and shrubs. There were significant differences in annual species composition among single shrub plots, and among quadrats differing in position relative to shrub canopy. There were no significant differences in annual plant species composition among the three shrub species on mixed shrub plots. Soil or other micro-environmental site differences, other than the species of shrub, must be responsible for differences in annual plant communities.}, keywords = {annual plant, distribution, annual plant, shrub association, dissertation, dissertations, shub, annual plant, theses, thesis}, author = {Lightfoot, Karen S.} } @conference {51604, title = {Alternative methods of seeding native lands}, booktitle = {Annual Meeting of the American Society of Agronomy}, year = {1990}, month = {October 21-26, 1}, pages = {163}, address = {San Antonio, TX}, abstract = {Mechanical reseeding of native and less productive lands is usually prohibitive. Native plants successfully utilize natural means, such as animals, water, or wind, to distribute their seeds. We are exploring the possibilities of using livestock, wildlife, and natural waterways for seed dispersal. Steers were bolused with gelatin capsules with known quantities of either a shrub, fourwing saltbush, or one of two grasses, blue panic grass or alkali sacaton. These species are adapted to arid range conditions. Up to 60\% of the seeds were recovered in steer feces within 72 hours after bolusing, and near normal germination resulted. Quail fed the grass seeds, passed over 95\% of the viable seed within 24 hours, and averaged 530 blue panic and 1,800 alkali sacaton seeds per bird. Observations were made of seed dispersed from seeded plots and from a flood activated seeder along natural drainage ways. The use of animals or water to disperse seeds of desirable forage species potentially could be an effective and economical means for establishing these species in areas where conventional methods are not practical.}, keywords = {alternative methods, livestock, native lands, natural waterways, seed dispersal, seeding, wildlife}, author = {J.R. Barrow and Kris Havstad and Gibbens, Robert P. and Donaldson, P.} } @article {51675, title = {Are deserts more variable than lakes?}, journal = {LTER Network News}, volume = {5}, year = {1989}, note = {//NMSU//LTER I//}, month = {Spring 1989}, pages = {8-9}, abstract = {An intersite activity is in full swing to explore new metrics for comparing similarities and differences in the temporal and spatial variability of diverse ecosystems. Variability is common to all ecological systems and is a feature which is thought to be important by ecologists.... Here we provide some preliminary results comparing the variability of two ecosystem types: a southwestern U.S. desert (the Jornada Desert LTER Site in New Mexico) and northern temperate lakes ( the North Temperate Lakes LTER Site in Wisconsin).}, keywords = {article, articles, ecosystem, variability, journal, journals}, author = {J. J. Magnuson and T. K. Kratz and Gary L. Cunningham} } @article {51690, title = {Activation of liquid bait devices by coyotes in southern New Mexico}, journal = {Wildlife Society Bulletin}, volume = {17}, year = {1989}, note = {//??//NONE//}, month = {1989}, pages = {306-312}, keywords = {article, articles, coyote,liquid bait, journal, journals}, author = {H. W. Stolzenburg and V. W. Howard Jr.} } @article {51700, title = {Abiotic controls on the functional structure of soil food webs}, journal = {Biology and Fertility of Soils}, volume = {8}, year = {1989}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1989}, pages = {1-6}, abstract = {

The hypothesis that the trophic structure of soil food webs changes as a result of the abiotic environment was examined by reviewing studies of soil biota. In dry soils with a water potential below -1.5 MPa, most bacteria, protozoans, and many species of nematodes are not active. These taxa persist in the soil in a state of anhydrobiosis. Because soil fungi grow at soil water potentials of -6.0 to -8.0 MPa, soil food webs in dry environments appear to be fungal-based and fungal grazers in dry environments appear to be predominantly fungiphagous mites. There is indirect evidence that some species of fungiphagous mites remain inactive in dry soils in a state of "crytobiosis". In habitats where there is insufficient vegetative cover to shade and modify the soil surface, the functional soil food web consists of fungi and a few taxa of soil acari for extended periods of time.

}, keywords = {abiotic,food webs, anhydrobiosis, article, articles, bacteria,food web, cryptobiosis, food web, abiotic controls, fungi,food web, journal, journals, mite,food web, nematode,food web, protozoa,food web, soil, food web}, doi = {10.1007/BF00260508}, url = {files/bibliography/JRN00089.pdf}, author = {Walter G. Whitford} } @article {51733, title = {Abundance and diversity of surface-active collembola along a watershed in the northern Chihuahuan Desert}, journal = {The American Midland Naturalist}, volume = {119}, number = {1}, year = {1988}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1988}, pages = {21-30}, abstract = {

Jackknife diversity estimates (n2= inverse Simpson diversity index) for surface-active Collembola were examined along a watershed in the Chihuahuan desert of southern New Mexico. Chord distance measures indicated low similarity in collembolan species composition among the six sites. However, assemblages at the top (black grama grassland) and bottom (mesquite fringe of playa) of the gradient were similar to each other, possibly reflecting available soil nitrogen. There was no significant correlation between Collembola and either weekly or long-term precipitation patterns. Populations of truly epigeic Collembola appeared unaffected by rainfall but were significantly, though weakly, correlated with long-term temperatures.

}, keywords = {article, articles, collembola, journal, journals, list, Collembola, microarthropod, Collembola, transect, Collembola, transect, microarthropods}, doi = {10.2307/2426050 }, url = {files/bibliography/JRN00067.pdf}, author = {S. J. Loring and Danforth Weems and Walter G. Whitford} } @mastersthesis {51711, title = {Associative nitrogen fixation with C4 grasses of the northern Chihuahuan Desert}, year = {1988}, note = {//NMSU//LTER I//}, month = {1988}, pages = {134}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = { Increasing evidence has been accumulating supporting significant grass-diazotrophic associations. However, characterization of these associations in hot desert grasses is lacking....Inoculation studies were conducted on the C4 perennial grass, Sporobolus cryptandrus, under greenhouse conditions. In the first experiment, inoculated plants had greater height, more tillers, longer flag leaf length, greater root length, more biomass, greater nitrogenase activities, and higher N content than control plants. The nitrogenase activity was greater during the vegetative phase than reproductive phases of the grass. In the second experiment, clipping after inoculation had similar significant effects on plant parameters and N content. However, nitrogenase activity and N concentration in plants and soil were lower than in the first experiment. The mixed culture treatment had the major positive effect on the grass in both experiments. The results indicated that associative N2 fixation may be ecologically important in N2 fixation and cycling in the Chihuahuan Desert.}, keywords = {dissertation, dissertations, grass, diazotrophic associations, grass, nitrogen fixation, nitrogen fixation,C4 grasses grass, C4,nitrogen fixation, plant, also SEE , plant,Sporobolus, Sporobolus,nitrogen fixation, theses, thesis}, author = {Ahmed F. El Shahaby} } @proceedings {51763, title = {An analysis of runoff and sediment yield from natural rainfall plots in the Chihuahuan Desert}, volume = {General Gechnical Report RM-150}, year = {1987}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//ProCite field[6]: In}, month = {1987}, pages = {196-200}, publisher = {USDA Forest Service, Rocky Mountain Forest and Range Experiment Station}, abstract = { This paper examines 17 rainfall-runoff events from four natural rainfall plots in southern New Mexico. There are nine plots located at the Jornada Long Term Ecological Research (LTER) site north of Las Cruces, New Mexico. Five plots have been treated with chlordane to remove termites and four are located on areas without the chlordane treatment. The plots (2m x 2m) were set up to represent shrub and intershrub areas. The common shrub in the area is creosote (Larrea tridentata). The shrubs are approximately centered in the plots. The intershrub plots have no creosote and very little perennial cover. Similarities and differences between plot responses to rainfall events were investigated, and the findings are related to plot and rainfall differences. Only the plots without the chlordane treatment will be discussed because the intent is to assess rainfall-runoff and sediment yield in a natural setting. Numerous statistical tests and comparisons were conducted on the data. The SAS package on the New Mexico State University IBM 3081D mainframe was used to summarize and analyze the data. The data were provided from an on-going LTER project at the Jornada (W. G. Whitford, Dept. of Biology, New Mexico State University, unpublished data).}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, hydrology, runoff, hydrology, sediment yield, Larrea,hydrology, proceeding, proceedings, rainfall, also SEE , surface runoff}, author = {Bolin, Susan B. and Timothy J. Ward}, editor = {Earl F. Aldon and Carlos E. Gonzale Vicente and Moir, William H. (eds.)} } @article {51768, title = {Accuracy of soil thermocouple hygrometer measurements in desert ecosystems}, journal = {Ecology}, volume = {68}, number = {4}, year = {1987}, note = {//NMSU//LTER I//}, month = {1987}, pages = {1121-1124}, abstract = {

The use of thermocouples in studies of soil and plant water relations began in the 1950{\textquoteright}s (Spanner 1951, Monteith and Owen 1958, Richards and Ogata 1958, Savage and Cass 1984). Initially, thermocouples were used only in laboratory studies because precise temperature control was thought to be essential for accurate measurements (Kramer 1972). Field applications began after Rawlins and Dalton (1967) and Wiebe et al. (1970) demonstrated that certain corrections eliminated the need for precise control. With the advent of commercial availability, thermocouples have been widely used by plant ecologists (see Turner and Kramer 1980 for examples). Despite their extensive use, many investigators are distrustful of data obtained with soil thermocouples. The prevelence of this distrust, although not expressed in the literature, is commonly expressed in discussions among scientists who have had field experience with thermocouples. We compared soil water potential data obtained with soil thermocouples to measurements ofpredawn xylem sap potential of desert shrubs (Scholander et al. 1965, Waring and Cleary 1967). The null hypothesis tested was that predawn xylem sap potentials would not differ significantly from soil water potential values measured with soil thermocouples in the dew point mode (hygrometers), because xylem sap potentials at that time are in equilibrium with rhizosphere water potential (Ritchie and Hinkley 1975).

}, keywords = {article, articles, Gutierrezia,xylem sap potential, hygrometer, soil thermocouple, journal, journals, Larrea,xylem sap potential, soil water potential,technique, soil, thermocouple hygrometer, technique,soil thermocouple hygrometer, thermocouple, accuracy}, doi = {10.2307/1938388 }, url = {files/bibliography/JRN00050.pdf}, author = {P. J. Fonteyn and W. H. Schlesinger and G. M. Marion} } @book {51800, title = {Approaches for studying the function of deep root systems}, series = {Plant Response to Stress}, number = {Vol. G15}, year = {1987}, note = {//OTHER//NONE//ProCite field[6]: InProCite field[32]: NATO ASI Series}, month = {1987}, pages = {107-127}, publisher = {Springer-Verlag}, organization = {Springer-Verlag}, address = {Berlin Heidelberg}, abstract = {

The potential importance of deep root systems to plant function has long been recognized. Until recently there have been few attempts to actually quantify the importance of deep roots in securing water and nutrients. The development of new methods and approaches which allow direct and indirect study of deep root function offers new and exciting possibilities. Modern drilling equipment can extract deep soil samples with minimal disturbance to roots and the soil biota. The application of stable isotope techniques using variations in natural abundance is especially exciting since analysis of easily collected aboveground tissues provides information on the function of deep root systems. Information on symbiotic nitrogen fixation and the identification of water sources used by the plant can be obtained with this approach. Although poorly described in natural systems, the structure, species composition and population densities of soil rhizosphere biota may proved information on the relative extent of root activity at a particular soil depth. The application of more than one of these approaches to a single system provides the best opportunity to better understand the functional importance of deep roots to plants.

}, keywords = {biochemistry, deep root systems, book, books, chapter, chapters, fungi, also SEE , mycorrhizal fungi, deep root systems, nematode, deep root systems, nutrients, deep root systems, report, reports, root association, root biomass, root length, root systems, deep, technique, deep root systems, water uptake, deep root systems}, author = {R. A. Virginia and W. M. Jarrell}, editor = {Tenhunen, J. D.} } @article {51820, title = {Abundance, distribution, biomass and energetics of soil nematodes in a northern Mojave Desert ecosystem}, journal = {Pedobiologia}, volume = {29}, year = {1986}, note = {//OTHER//??//}, month = {1986}, pages = {129-142}, keywords = {article, articles, journal, journals, nematode, abundance, nematode, biomass, nematode, distribution, nematode,energetics, soil nematode, SEE }, author = {D. W. Freckman and Mankau, R.} } @book {51851, title = {Adaptive strategies of desert shrubs with special reference to the creosotebush (Larrea tridentata [DC] Cov.)}, series = {Pattern and Process in Desert Ecosystems}, year = {1986}, note = {//NMSU//NONE, LTER//ProCite field[6]: In}, month = {1986}, pages = {19-49}, publisher = {University of New Mexico Press}, organization = {University of New Mexico Press}, address = {Albuquerque, New Mexico}, abstract = {In this paper, my objective is, first, to discuss the biology of the creosotebush in terms of a static definition of its adaptive strategy, and, second, to present an overview of the approach that we{\textquoteright}re using to model the dynamic features of the adaptive strategy of Larrea in the Chihuahuan Desert. The value of the approach for hypothesis testing will be evaluated with regard to its potential as a tool for increasing our understanding of plant adaptations in arid environments.}, keywords = {book, books, chapter, chapters, Larrea, adaptive strategies, model,Larrea, model,shrubs,adaptive strategies, report, reports, shubs, adaptive strategies}, author = {J. F. Reynolds}, editor = {Walter G. Whitford} } @article {51866, title = {Applications of spatial analyses in field studies on soil moisture}, journal = {Transactions XIII Congress of the International Society of Soil Science}, volume = {IV}, year = {1986}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1986}, pages = {1622-1624}, keywords = {article, articles, journal, journals, soil moisture}, author = {Peter J. Wierenga} } @article {51874, title = {Adhesive technique for capture of burrow-dwelling spiders}, journal = {Journal of Arachnology}, volume = {13}, year = {1985}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1985}, pages = {395}, keywords = {article, articles, Geolycosa,capture technique, Geolycosa,parasitism, Geolycosa,predation, insect, also SEE , journal, journals, spider, burrow-dwelling, spider, Geolycosa, spider, parasitism, spider, predation, spider, wolf spider, Geolycosa, technique, adhesive (wolf spider)}, url = {files/bibliography/JRN00018.pdf}, author = {Marsha R. Conley} } @article {51889, title = {Analysis of above-ground gallery construction by the subterranean termite Gnathamitermes tubiformans (Isoptera: Termitidae)}, journal = {Environmental Entomology}, volume = {14}, year = {1985}, note = {//NMSU//LTER I//}, month = {1985}, pages = {470-474}, abstract = {

Gnathamitermes tubiformans (Buckley), a common termite species in the northern Chihuahuan Desert of North America, builds mud galleries around standing dead vegetation and other food materials after periods of rain. The termites graze only the surface of standing dead branches, tissues highest in nitrogen content. We hypothesized that termites invest more energy in gallery construction than they obtain from the wood they consume. We estimated energy costs of gallery construction from analysis of gallery material and construction behavior of the termites. In addition to obtaining a food source relatively high in nitrogen, the estimated energy invested in gallery construction. Therefore, the termites obtain much more energy from wood than they invest in gallery construction.

}, keywords = {article, articles, decomposition, aboveground, decomposition, termite, Gnathamitermes, journal, journals, nitrogen, termite, termite, gallery construction, termite, Gnathamitermes, termite, wood nitrogen}, doi = {10.1093/ee/14.4.470}, url = {files/bibliography/85-EnvEnt-Whitford.pdf}, author = {William P. MacKay and Blizzard, James H. and Miller, Jacqueline J. and Walter G. Whitford} } @inbook {51917, title = {Advances in reproductive management techniques for more efficient and profitable lamb production}, year = {1984}, month = {1984}, pages = {359-367}, publisher = {Winrock International, Westview Press}, organization = {Winrock International, Westview Press}, address = {Boulder, CO}, abstract = {

From about 1960 until 1980, sheep numbers in the U.S. declined steadily from about 35 million down to about 12 million head. The rapid and large decline greatly concerned sheep industry leaders because volume is often critical to efficient marketing, transporting, slaughtering, and merchandising.

}, url = {/files/bibliography/262.pdf}, author = {Clarence V. Hulet}, editor = {Baker, F.H. and M. Miller} } @inbook {51916, title = {Animal behavior and production efficiency}, year = {1984}, month = {1984}, pages = {387-397}, publisher = {Winrock International, Westview Press}, organization = {Winrock International, Westview Press}, address = {Boulder, CO}, abstract = {

Animal performance is greatly affected by stress that can result from physical, social, mental, psychological, and emotional factors, individually or in combinations. It has been documented that cattle gain better when cared for by a kindly gentle person than by one who dislikes cattle. Emotional stress can cause duodenal ulcer and death in dogs. There is no reason to believe that sheep are not subjected to emotional and psychological stress. The stress of weaning, shipping, and even a change of feed can lead to poor performance and even illness and death. The objective of this discussion is to make us more aware of social, emotional, and psychological factors that may limit or enhance productivity in sheep.

}, url = {/files/bibliography/263.pdf}, author = {Clarence V. Hulet}, editor = {Baker, F.H. and M. Miller} } @inbook {51937, title = {Accelerated lambing: Its role in the sheep industry}, booktitle = {Sheep and Goat Handbook}, year = {1983}, month = {1983}, pages = {171-178}, publisher = {Winrock International, Westview Press}, organization = {Winrock International, Westview Press}, address = {Boulder, CO}, abstract = {

The cost of maintaining a ewe for a year is often quite high, and unless the returns from lamb and wool exceed these costs by a reasonable amount, a sheep enterprise will not be profitable. Thus, increasing the frequency of lambing or the number of lambs born per lambing, or both, without a comparable increase in maintenance and labor costs, should increase net return. Any increase in the number of lambings in relationship to the age of the ewe is referred to as accelerated lambing and includes: 1) starting lamb production at a younger age, and 2) breeding and lambing at intervals more frequent than 12 months.

}, url = {/files/bibliography/242.pdf}, author = {Clarence V. Hulet and Stellflug, J.N.}, editor = {Baker, F.H.} } @article {51959, title = {Annual variations in patterns of reproduction of the cactus wren (Campylorhynchus brunneicapillus)}, journal = {The Southwestern Naturalist}, volume = {28}, year = {1983}, note = {//LOCAL//NONE//}, month = {1983}, pages = {149-156}, keywords = {article, articles, bird, Cactus wren, bird, Campylorhynchus, Cactus wren, annual variations, Cactus wren, breeding, Cactus wren, foraging ecology, Cactus wren,reproduction, journal, journals}, author = {T. G. Marr and Ralph J. Raitt} } @article {51960, title = {Arid land seeder development}, journal = {Rangelands}, volume = {5}, number = {6}, year = {1983}, month = {December 1983}, pages = {267-269}, chapter = {267}, abstract = {

A major problem confronting range managers in arid and semiarid climates is the need to find new initiatives for improving rangeland. In the western and plains States, approximately 836 million acres are used primarily for livestock grazing and for wildlife habitat. Of this acreage, only 170 million acres are classified in good condition. The remaining acreage has been taken over by undesirable brush. Much of this rangeland can be improved, or converted from brush to desirable grass and forbs, through recent equipment development efforts. This can be accomplished by rootplowing or plowing with the Brush land Plow and then seeding with the Rangeland Drill. However, in the very arid areas of less than 11 inches of rainfall per year, conventional methods and equipment have not been economical or successful enough to justify or encourage their use.

}, url = {/files/bibliography/221.pdf}, author = {McKenzie, D.W. and C.H. Herbel} } @mastersthesis {51962, title = {An analysis of activity patterns in the grasshopper mouse (Onychomys leucogaster): Abiotic factors as predictive variables}, year = {1983}, note = {//NMSU//NONE//}, month = {1983}, pages = {24}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Biweekly standard North American snap trap census lines were run between 15 February 1979 and 8 May 1981 on the Jornada Experimental Range in southcentral New Mexico. Vegetatively, the study area represents northern Chihuahuan Desert. A trapping effort represented by 42,480 trap nights produced 14 species of desert rodents, with Onychomys leucogaster being second in abundance to Dipodomys ordii. Trapping frequency data for O. leucogaster were used to examine the relationship of activity patterns to moon phase, cloud cover, precipitation, temperature, evaporation, wind, and covariate terms derived from these. Regression analysis revealed the significant variables "new moon" and "minimum temperature"; however, these two attributes explain only 11\% of the variance in trap-revealed activity. Activity patterns in O. leucogaster thus appear to be generally independent of abiotic influences.}, keywords = {behavior, Onychomys, dissertation, dissertations, Onychomys, activity patterns, rodent, Onychomys, theses, thesis}, author = {Marian Matilda Miller} } @article {51981, title = {Adaptation and application of a surface erosion model for New Mexico forest roadways}, year = {1983}, note = {//OTHER//NONE//}, month = {1983}, institution = {New Mexico Water Resources Research Institute}, address = {Las Cruces, New Mexico}, abstract = {The most significant source of sediment in forest environments is poorly planned, constructed or maintained roadways. Roadways change drainage patterns, expose the soil, disturb vegetation, and alter existing slope gradients. This study was conducted to compare effectiveness of measures and associated costs. Data collected from forest roadways on four national forest in New Mexico were used to derive parameters for an existing computer based erosion and sediment yield model. The model was used to estimate sediment yields for different control measures. Yields were compared with costs of measures which were provided through a survey of forest engineers in Arizona and New Mexico. Results show the different costs of using various methods for reducing a unit of sediment yield from forest roadways, and can be used to help determine a best management method.}, keywords = {book, books, chapter, chapters, hydrology, model, hydrology,infiltration, hydrology,processes, hydrology,runoff, hydrology,sediment yield, model,hydrology, rainfall simulation, report, reports, soil erosion}, isbn = {WRRI Report No. 188}, author = {Timothy J. Ward and Seiger, Andrew D.} } @article {52025, title = {Aspects of desertification in Prosopis dunelands of southern New Mexico, USA}, journal = {Journal of Arid Environments}, volume = {5}, year = {1982}, note = {//NMSU//NONE//}, month = {1982}, pages = {277-284}, abstract = {Mesquite shrubs in long-established plots registered increases in numbers and cover for most observation periods, in spite of drought, herbicide treatment and protection from grazing. The few decreases noted seem to be accounted for by drought and herbicide. Changes in the biotic and physical environment are incorporated into a model that shows their respective roles in effecting the conversion from grass- to shrub-dominated ecosystems.}, keywords = {article, articles, brush control,herbicide, climate,also SEE , community, Prosopis, desertification,Prosopis dunelands, herbicide, brush control, journal, journals, model, desertification, model, water budget, Prosopis duneland,desertification}, author = {Robert Anderson Wright} } @proceedings {52028, title = {Application of current livestock-range knowledge and emphasis needed for the future}, year = {1981}, note = {Reproduced by kind permission of CSIRO PUBLISHING, Melbourne Australia, from Forage evaluation: concepts and techniques: proceedings of a workshop entitled {\textquoteright}Forage evaluation and utilization - an appraisal of concepts and techniques{\textquoteright}held in Armidale, N.S.W., 27-31 October, 1980, under the auspices of the U.S./Australia Cooperative Science Program / editors: J.L. Wheeler, R.D. Mochrie. Published jointly by CSIRO Australia and the American Forage and Grassland Council, 1981.}, month = {1981}, pages = {535-542}, address = {Armidale, NSW, Australia}, abstract = {

In an attempt to document and evaluate the extent to which practices resulting from livestock and range research are being applied in the 17 Western states in the United States, 62 survey questionnaires were mailed during July, 1980, to extension specialists in livestock and range sciences. The questionnaire also contained a section in which the respondents were asked to indicate on specific questions whether information was available, unavailable or of limited interest. The limited number of responses made formal statistical inferences impossible. However, two trends were revealed: (1) accurate and precise information either does not exist or is not readily available on the extent to which specific practices in livestock and range sciences are being applied, and (2) extension specialists in the livestock and range sciences differ in their opinion on what topics require further research. A statistically analyzable questionnaire returned from an adequately sized, random sample of research, extension and producer personnel is needed if we are to determine the extent to which research information is being applied and to indicate the emphasis for future research.

}, keywords = {application, livestock research, livestock-range knowledge, range research}, url = {/files/bibliography/191.pdf}, author = {D.M. Anderson} } @proceedings {52041, title = {Arid land seeding}, year = {1981}, month = {1981}, pages = {8-9}, url = {/files/bibliography/197.pdf}, author = {C.H. Herbel} } @article {52055, title = {Absorption of SO2 by pecan (Carya illinoensis [Wang] K. Koch) and alfalfa (Medicago sativa L.) and its effect on net photosynthesis}, journal = {Journal of Experimental Botany}, volume = {32}, year = {1981}, month = {1981}, pages = {523-534}, url = {/files/bibliography/206.pdf}, author = {Sisson, W.B. and Booth, J.A. and Throneberry, G.O.} } @article {52064, title = {Ant communities of southeastern longleaf pine plantations}, journal = {Environmental Entomology}, volume = {10}, number = {2}, year = {1981}, note = {//OTHER//NONE//}, month = {1981}, pages = {183-185}, abstract = {

The ant community in a recent replant longleaf pine plantation on the Savannah River Plant, S.C. had the greatest species diversity and richness when compared to mature, thinned and burned pine plantations. Four species of ants dominated all pine plantations: Crematogaster lineolata (Say), Aphaenogaster traetae Forel, Aphaenogaster fulva Roger and Conomyrma insana Roger. There is an apparent relationship between the channelization of stumps, snags and dead logs by termites and densities of Crematogaster spp. Recent burning of pine straw had no measurable effect on the dominant tree bole/stump nesting species.

}, keywords = {ant community, longleaf pine, article, articles, journal, journals, longleaf pine, ant communities}, doi = {10.1093/ee/10.2.183}, url = {files/bibliography/81-EnvEnt-Whitford.pdf}, author = {Walter G. Whitford and Gentry, J. B.} } @mastersthesis {52070, title = {Application of simulation techniques to evaluate grazing management policies in the semidesert grasslands of southern New Mexico}, year = {1980}, note = {//NMSU//NONE//}, month = {1980}, pages = {182}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = { Recent adoption of systems concepts in natural resource management has emphasized the need for an integrative approach and interdisciplinary cooperation. This study was designed to demonstrate the usefulness of simulation as a framework for interdisciplinary research as an aid in evaluating ecological and economic consequences of grazing management policies. A computer simulation model describing a typical cow/calf ranching enterprise in the semidesert grasslands of southern New Mexico was constructed. The model was then used to compare key management policies that relate to the overall planning horizon of the rancher. The model variables were biomass of perennial forage plants, mesquite cover, numbers and biomass of the different classes of cattle. Management controls were designed through a set of fixed rules. The environment was simulated by the use of a stochastic rainfall generator and historical economic and market time series data. Twelve combinations of management alternatives concerning methods of stocking rate determination, range use and range improvement by shrub control were examined for their impacts on productivity and stability of the system. The simulation period was 50 years with a simulation interval of one year. Results of the model experiments based on the means showed that sustained herbage yield was highest when stocking rate was determined by the herbage residue method, least when stocking rate was constant and when use factor method was employed. Reducing use from heavy to moderate had a lesser impact on herbage production than the adoption of shrub control policies. sustained herbage yield was 8 to 10 percent higher as a result of reducing use from heavy to moderate compared to an increase of 27 to 38 percent by adopting control at low infestation levels instead of control at high infestation levels. Livestock production rates, however, showed greater sensitivity to range use policies than shrub control. Higher calving rates and weaning weights were scored under moderate use compared to heavy use. Total beef marketed under heavy use averaged 33 to 38 percent higher than beef marketed under moderate use. Feeding costs were higher when the range was stocked according to the residue method or use factor method compared to constant stocking rate. Differences in feeding costs were less, between stocking methods than between use policies and were highest between control policies. Judging relative merits of tested alternatives by the present values of net income, it was clear that constant stocking rate was superior to the other two methods, irrespective of use policy and mesquite control. When mesquite control was employed at low infestation levels, a shift from the residue method or use factor to the constant stocking rate method would reduce costs by a greater amount than would a reduction from heavy use to moderate using either of the methods. With minor exceptions, moderate use resulted in smaller losses than heavy use, regardless of mesquite control policies. Range improvement by mesquite control at low infestation levels, compared to control at high infestation levels, would reduce costs by $1500 to $5000 per section over a period of 50 years, depending on use policy. The model highlighted the lack of field data, especially information about herbage dynamics, quantitative data on rates of mesquite cover changes, livestock production rates in relation to herbage quantities and qualities and data on response to improvement practices. The study also pinpointed areas where more investigations are needed, such as the best timing for shrub control and the best method for adopting stocking and utilization standards.}, keywords = {dissertation, dissertations, grassland, grazing management, grazing, management, model,grazing management, theses, thesis}, author = {Abdalla, Suliman H.} } @conference {52103, title = {Absorption of SO2 by pecan (Carya illinoensis [Wang] K. Koch) leaflets and its effect on photosynthesis}, booktitle = {Plant Physiology}, volume = {65}, year = {1980}, month = {1980}, pages = {49}, author = {Sisson, W.B. and Throneberry, G.O. and Booth, J.A.} } @conference {52105, title = {Ambient temperature effects on photosynthesis and root respiration of intact Yucca elata Engelm}, booktitle = {Plant Physiology}, volume = {65}, year = {1980}, month = {1980}, pages = {Abstract 48}, author = {Sisson, W.B.} } @proceedings {52121, title = {Arid land seeding}, year = {1979}, month = {1979}, pages = {7-9}, abstract = {During the past year, an area on the Jornada Experimental Range infested with creosotebush and some honey mesquite was rootplowed and seeded with the arid land seeder prototype equipment developed in the 1960{\textquoteright}s. Lehmann and Boer lovegrasses, black and sideoats grama, yellow bluestem, blue panicgrass and forwing saltbush were used in the seeding. The Jornada Experimental Range is planning to treat about 200 acres with this equipment so the effects of rootplowing and seeding on the ecosystem can be studied. Other vegetative rehabilitation equipment that members of the workgroup are developing are a low-energy grubber, new rangeland seeder, disk chain and land imprinter.}, keywords = {arid land, arid land seeder, prototype, rootplowed, seeding}, url = {/files/bibliography/170.pdf}, author = {C.H. Herbel} } @proceedings {52154, title = {Arid land seeder}, year = {1978}, month = {1978}, pages = {12}, abstract = {A newly designed grubbing blade developed for front mounting on a rubber tire tractor and patterned after the low-energy gruber{\textquoteright}s blade (crawler tractor) appears very promising for controlling junipers 2 to 5 feet tall. Preliminary data indicate only a slight reduction in acre-per-hour performance while total investment will be approximately one-half. Fuel consumption is 72 percent less than that of a crawler tractor. The farm tractor tested was a 60-horse-power, John Deere 2440 with automatic reverse, foot-controlled throttle, 146 front-end loader frame, and special high-ply, used airplane tires adapted for farm tractors. The rubber-tire grubber averaged 6.3, 1.3, and 0.6 (acres per hour in densities of 50, 250, and 500 trees per acre). Production rates were computed using the curvilinear regression prediction equation Log Y = 2.49 Log X (r = .97) when Y = production (ac/hr) and X = densities/ac. The unit appears well suited to controlling extensive acreages of small junipers infesting previously cleared areas.}, keywords = {arid land seeder, creosotebush, effects on ecosystem}, url = {/files/bibliography/167.pdf}, author = {C.H. Herbel} } @article {52171, title = {An archaeological survey of nine seismographic test lines for Exxon company in Dona Ana and Luna counties, New Mexico}, year = {1978}, note = {//LOCAL//NONE//}, month = {1978}, institution = {Cultural Resources Management Division, New Mexico State University}, address = {Las Cruces, New Mexico}, keywords = {archaeology,survey, book, books, chapter, chapters, report, reports}, isbn = {Report 227}, author = {Weyer, J. K.} } @mastersthesis {52206, title = {Aerobic sporeforming bacteria in northern Chihuahuan Desert soils}, year = {1976}, note = {//NMSU//NONE//}, month = {1976}, pages = {101}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {A macroenvironmental approach was used to investigate the role of aerobic sporeforming bacteria in northern Chihuahuan Desert soils. The study site was an alluvial fan piedmont, or bajada, 40 km NNE of Las Cruces, New Mexico. Total viable counts in Bajada soils averaged 13 x 104 counts/g viable counts, or 7 x 104 spores/g soil. Although bacilli constituted a high proportion of the total viable counts in these soils, they occurred virtually entirely as metabolically inactive spores.}, keywords = {Bacillus,sporeforming, bacteria,sporeforming, dissertation, dissertations, soil, sporeforming bacteria, theses, thesis}, author = {Harding, Ethelynda E.} } @article {52249, title = {Anomalous diurnal patterns of stem xylem water potentials in Larrea tridentata}, journal = {Ecology}, volume = {56}, number = {6}, year = {1975}, note = {//NMSU//US-IBP//}, month = {1975}, pages = {1423-1428}, abstract = {Diurnal stem xylem H2O potentials of Larrea tridentata (DC.) Cov. were measured with a pressure chamber during the summers of 1973, 1974. Plants growing in dry soils had minimum stem xylem H2O potentials at night and maximum values during the daylight hours. Vertical H2) vapor movements in the soil profile in response to temperature gradients may be implicated although further data are needed to establish their role conclusively. Water vapor apparently moves up our to the rooting zone at night and back down into the rooting zone during the day. The occurrence of this phenomenon probably enhances the ability of Larrea shrubs to maintain photosynthetic activity when soil H2O potentials are low and makes questionable the use of predawn stem xylem H2O potential measurements to assess seasonal trends in plant H2O status.}, keywords = {article, articles, journal, journals, Larrea,photosynthesis, Larrea,stem xylem, Larrea,transpiration, photosynthesis, pressure bomb, soil water, vapor flux, stem xylem, water potentials, transpiration, water potential,Larrea stem xylem}, author = {J. P. Syvertsen and Gary L. Cunningham and Feather, T. V.} } @mastersthesis {52275, title = {Aspects of the thermal physiology of honey ants (Genus Myrmecocystus)}, year = {1974}, note = {//NMSU//NONE//}, month = {1974}, pages = {74}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {1. Critical thermal maxima and minima, temperature preferences and rates of O2 consumption were determined for diurnal and nocturnal species of honey ants of the genus Myrmecocystus.}, keywords = {ant, Myrmecocystus, ant, physiology, dissertation, dissertations, honey ant, Myrmecocystus, physiology, ants, theses, thesis}, author = {Carol Ann Kay} } @article {52298, title = {Adaptation of the tiger salamander, Ambystoma tigrinum, to arid habitats}, journal = {Comparative Biochemistry and Physiology}, volume = {46A}, year = {1973}, note = {//LOCAL//NONE//}, month = {1973}, pages = {631-638}, abstract = {

1. During long-term dehydration, the tiger salamander, Ambystoma tigrinum, is able to tolerate high plasma fluid concentration (\>550 mOsmole/l.).

2. An increase in plasma solute concentration followed by the production and accumulation of urea accounted for increased plasma concentration during dehydration.

3. The \"benevolent bladder\" hypothesis proposes that differential reabsorption of water and salts regulates plasma concentration during long-term dehydration.

}, keywords = {Ambystoma, adaptation, Ambystoma,behavior, Ambystoma,physiology, amphibian, Ambystoma, amphibian,tiger salamander,Ambystoma, article, articles, journal, journals}, doi = {10.1016/0300-9629(73)90116-3}, url = {files/bibliography/73-CompBiochemistryandPhys-Whitford.pdf}, author = {Jeff Delson and Walter G. Whitford} } @article {52321, title = {Air temperatures, air relative humidity, and solar radiation studies at the Jornada site}, year = {1973}, note = {//??//US-IBP//}, month = {1973}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {air temperature, book, books, chapter, chapters, climate, relative humidity, report, reports, solar radiation}, isbn = {Research Memorandum 71-5, 72-4, 73-4, 74-4}, author = {Walter G. Whitford and J. Ludwig} } @article {52323, title = {Annual and perennial grass and forb production in a desert ecosystem}, year = {1973}, note = {//??//US-IBP//}, month = {1973}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {book, books, chapter, chapters, forb,production, grass, production, report, reports}, isbn = {Research Memorandum 73-29}, author = {Walter G. Whitford} } @article {52328, title = {Analysis of habitats of two woodrats in southern New Mexico}, journal = {Journal of Mammalogy}, volume = {54}, number = {2}, year = {1973}, note = {//LOCAL//NONE//}, month = {1973}, pages = {529-535}, abstract = {The white-throated woodrat, Neotoma albigula albigula Hartley, and the southern plains woodrat, Neotoma micropus canescens J.A. Allen, have sympatric ranges in New Mexico and Texas (Hall and Kelson, 1959). However, the literature on the two species indicates general habitat segregation, both in New Mexico and in Texas.... Present habitat distribution of albigula and micropus in the Mesilla Valley of southern New Mexico based on locality data from specimens at New Mexico State University, is not as distinctively separate as is indicated by the literature. Therefore, this study was undertaken to determine the current distribution and density of the two species of Neotoma relative to variations in vegetation and soil; special attention was given to the question of degree of coexistence. Results are interpreted in light of documented changes in occurrence of the two species of Neotoma and of their habitats. Field work was conducted in the period of May 1964 to July 1965.}, keywords = {article, articles, journal, journals, Neotoma,habitat, rodent, woodrat, rodent,Neotoma}, author = {Wright, Michael E.} } @proceedings {52371, title = {Abiotic factors in grassland ecosystem analysis and function}, year = {1971}, note = {//USDA//US-IBP//NMSU library QH541.5 .P7 .P74//ProCite field[6]: In}, month = {September 1971}, pages = {11-34}, publisher = {Colorado State University}, address = {Colorado State University, Fort Collins, Colorado}, abstract = {

The time and space distributions of the abiotic driving forces are the topics of consideration of this paper. The climate as defined by solar radiation, temperature, precipitation, evaporation, runoff, and wind is discussed. The distribution of these quantities across the grassland of the United States is shown by a series of maps developed from the long-term climatic records. Discussion of these parameters is focused on the factors that delineate the boundaries of the grassland and variations within the grassland area. A simple energy and water balance of the earth-atmosphere interface is described (Thornthwaite-Mather model), and the model is applied to the mean monthly data at each of seven IBP Grassland Biome intensive observation plots. Characteristic soil moisture variations for each site are computed, and intersite comparisons are made. An identical analysis is performed for the 1970 data at each site. Variations in 1970 soil moisture between sites as well as deviations from the long-term average are noted.

}, keywords = {abiotic,grassland, abstract, abstracts, climate,grassland, conference, conference proceedings, conferences, evapotranspiration,grassland, grassland,abiotic factors, model, Thornthwaite-Mather, model,energy \& water balance, proceeding, proceedings, soil, moisture}, author = {Rasmussen, James L.}, editor = {Norman R. French} } @article {52380, title = {Avian ecology and distribution in the comprehensive network, 1970}, year = {1971}, note = {//USDA//US-IBP//}, month = {1971}, institution = {Colorado State University}, address = {Ft. Collins, Colorado}, keywords = {avian distribution, avian ecology, bird, also , book, books, chapter, chapters, report, reports}, isbn = {Technical Report No. 77}, author = {J.A. Wiens} } @article {52422, title = {Aerial applications of ultra-low-volume insecticides to control the horn fly on unrestrained range cattle}, journal = {Journal of Economic Entomology}, volume = {62}, year = {1969}, note = {//??//NONE//New Mexico Agr. Exp. Station Journal Article 323}, month = {1969}, pages = {1515-1516}, keywords = {article, articles, cattle,parasite, horn fly,insecticide, insecticide,aerial application, insecticide,horn fly, journal, journals}, author = {Kinzer, H. G.} } @article {52428, title = {Aerial and aquatic respiration in axolotl and transformed Ambystoma tigrinum}, journal = {Herpetologica}, volume = {24}, number = {3}, year = {1969}, note = {//USDA//NONE//}, month = {1969}, abstract = {

Studies dealing with the role of the skin, lungs, and buccopharyngeal cavity in respiration in salamanders (Whitford and Hutchison, 1963, 1965, and 1966) have been confined to an analysis of gas exchange in an air environment. In the semidesert and desert areas of the Southwest, populations of the tiger salamander, Ambystoma tigrinum, spend much of their life in semi-permanent or permanent bodies of water. Consequently, an evaluation of the role of the various respiratory surfaces in this species must be conducted in an aquatic environment to determine the role of the skin, lungs, and gills in aquatic respiration when the animals are able to obtain atmospheric oxygen by surfacing. In New Mexico some populations are composed of both transformed and neotenic adults (axolotls). The factors leading to the failure of metamorphosis are not know nor is the adaptive significance of neoteny in these populations understood. Studies of gas exchange in both life forms of adult A. tigrinum could aid in an interpretation of ecological and physiological adaptations to pond environments.

}, keywords = {Ambystoma,respiration, amphibian, Ambystoma, amphibian,physiology, article, articles, journal, journals, physiology,amphibian}, url = {files/bibliography/69-Herpetologica-Whitford.pdf}, author = {Walter G. Whitford and Sherman, Robert E.} } @article {52432, title = {Age and comparative development of desert soils at the Gardner Spring radiocarbon site, New Mexico}, journal = {Soil Science Society of America Proceedings}, volume = {32}, number = {5}, year = {1968}, note = {//USDA//NONE//}, month = {1968}, pages = {709-716}, abstract = {Radiocarbon ages have been obtained from seven buried charcoal horizons in a desert area of southern New Mexico. Several deposits of highly calcareous alluvium range in age from less than 1,100 to somewhat greater than 5,000 years and are therefore of Recent age. Pleistocene deposits much older than 5,000 years also occur. Pleistocene soils of adjacent topographic highs were a major source of the Recent sediments. Evidence in this area indicates that the present climate is warmer and drier than the Pleistocene pluvial climates. This change to a drier and warmer climate could have decreased the vegetative cover in places and started strong erosion of Pleistocene soils in these areas. The date charcoal also establishes a maximum, and in some instances a minimum age for several soils formed in the deposits. With increasing age of soil during Recent time, the progression of soil development appears to have been marked by development of a A horizon, destruction of thin sedimentary strata, slight accumulation of carbonate, development of structure in materials of sufficently fine texture, and, with continued carbonate accumulation, development of a weak calcic horizon. In contrast, soils of Pleistocene age can have distinct argillic horizons and strong horizons of carbonate accumulation. It is postulated that the wetter climates of Pleistocene pluvials, associated with greater vegetative cover and landscape stability, were required for development of argillic horizons in these highly calcareous parent materials.}, keywords = {article, articles, geomorphology, journal, journals, radiocarbon dating, soils, soil, age, soil, also SEE , soil, charcoal horizons, soil, classification, soil, development, soil, landscape, soil, radiocarbon dating, soil,paleosols}, author = {L. H. Gile and J. Hawley} } @article {52465, title = {Activities of hereford and Santa Gertrudis cattle on a southern New Mexico range}, journal = {Journal of Range Management}, volume = {19}, number = {4}, year = {1966}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {July 1, 1966}, pages = {173-176}, abstract = {Only a few studies have compared the performance of two breeds of cattle on rangelands of the United States. Although Herefords are the dominant breed in the Southwest, cattle with some Brahman blood may be better adapted to the hot, arid environment. This study was conducted to determine the differences, if any, in performance of Hereford and Santa Gertrudis cattle on rangeland.}, keywords = {cattle, hereford, performance, rangeland, Santa Gertrudis, southern New Mexico}, url = {/files/bibliography/098.pdf}, author = {C.H. Herbel and Nelson, A.B.} } @article {52470, title = {Australian Arid-Zone Research Conference}, journal = {Journal of Range Management}, volume = {19}, number = {3}, year = {1966}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {May 1, 1966}, pages = {161-162}, abstract = {The second Australian Arid-Zone Conference was held at Alice Springs, September 12 to 17, 1965. A 4-day pre-conference tour visited the Ayres Rock-Mt. Olga area, a round trip of about 700 miles with stops to observe various plant communities. About 125 delegates registered. The various subjects were covered by a review speaker who presented both published and unpublished materials and a discussion leader who summarized the contributed papers. One-third to half the allotted time was usually allowed for discussion. A copy of the condensed papers had been mailed to each delegate 3 or 4 weeks beforehand to permit time for preparation of questions and discussion. The subjects covered with some of the points of interest to the author are presented here.}, keywords = {Australian Arid-Zone Conference}, url = {/files/bibliography/094.pdf}, author = {C.H. Herbel} } @proceedings {52473, title = {Activities and species preference of hereford and Santa Gertrudis range cows}, volume = {17}, year = {1966}, month = {1966}, pages = {403-408}, abstract = {Diurnal activities of beef cattle and the plant species grazed during various seasons are important in formulating grazing management plans and for nutritional studies. Breeds of cattle may perform differently on rangelands of southern New Mexico. Hereford is the predominant breed in the Southwest. Santa Gertrudis, whose genetic background includes the Brahman, may be better adapted to the hot, arid environment of this area. The purpose of this study is to determine the differences, if any, in the activities and species preference of Hereford and Santa Gertrudis cows.}, keywords = {activities, hereford, range cattle, Santa Gertrudis, species preference}, url = {/files/bibliography/101.pdf}, author = {Nelson, A.B. and C.H. Herbel} } @mastersthesis {52488, title = {Analysis of the coyote population of Dona Ana County, New Mexico}, year = {1965}, note = {//LOCAL//NONE//}, month = {1965}, pages = {39}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {The status of the coyote population in south-central New Mexico was studied during 1964 and 1965. Analysis of a dynamic life table indicates that the coyote population in south-central New Mexico is stationary. Two methods of relative census, catch per trap-night and density contact index, indicate that coyotes are equally abundant on the mesquite dune type and the desert grassland type.}, keywords = {coyote population, demography, coyote, dissertation, dissertations, theses, thesis, vertabrate, coyote}, author = {Rogers, John G.} } @mastersthesis {52510, title = {The accuracy, precision and efficiency of the point series method of vegetation sampling with reference to the low vegetative cover of the semi-desert grassland}, year = {1961}, note = {//??//NONE//}, month = {1961}, pages = {40}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {A study was conducted to determine the accuracy, precision and comparative efficiency of the point series method of vegetation sampling. Accuracy and precision were determined in the laboratory on a known artificial population and in the field under natural conditions. Efficiency was determined from the fields and laboratory data. Artificial population values and values obtained with the line interception method of Canfield were used as standards for comparison. Accuracy, precision and efficiency levels were determined for 1 foot, 2 foot and 5 foot observation point intervals. When point observations were made at 1 foot and 2 foot intervals on 1 percent and 3 percent basal cover levels, the method was accurate for estimating cover. However, when observations were made at the 5 foot intervals, the method was not accurate. The method was not accurate for estimating true basal cover at the 5 percent basal cover level at any of the observation intervals. Basal cover levels obtained with the point series method and the standard method did not differ significantly. The precision and efficiency levels of the point series method were lower than those of the standard method, and the precision and efficiency of the point series method decreased as the observation point interval increased.}, keywords = {community, see ALSO , dissertation, dissertations, plant community, vegetation sampling, technique, vegetation sampling, theses, thesis, vegetation sampling}, author = {Baca, Edward C.} } @article {52526, title = {Age incidence and heritability of cancer eye in Hereford cattle}, journal = {Journal of Animal Science}, volume = {15}, year = {1956}, note = {//??//NONE//(New Mexico Agr. Exp. Station Journal Article 101)//}, month = {1956}, pages = {943-951}, keywords = {article, articles, cattle,disease,cancer eye, cattle,genetics,cancer eye, disease,cancer eye, genetics,cancer eye, journal, journals}, author = {Blackwell, R. L. and D.M. Anderson and Knox, J. H.} } @article {52579, title = {Application of the line interception method in sampling range vegetation}, journal = {Journal of Forestry}, volume = {39}, year = {1941}, month = {1941}, pages = {388-394}, abstract = {The line interception method as herein described is designed for measuring density and composition of herbaceous vegetation and shrubs. It is based primarily on the line transect. However, it incorporates a new technique for obtaining an inventory of the vegetation by line measurement of individual plants on a randomly selected sample. It appears to offer a practical, rapid and statistically sound means for sampling vegetation on both large and small range areas, as well as on small plots used in detailed and intensive studies. Field tests have demonstrated that subjective influences are largely eliminated as factors affecting inventories so obtained. The method while primarily developed for range studies should also serve equally well to measure minor vegetation and stands of reproduction in forests.}, keywords = {large and small range, line interception method, line transect, sampling range vegetation}, url = {/files/bibliography/057.pdf}, author = {Canfield, R.H.} } @article {52598, title = {Amphibians and reptiles of Jornada Experimental Range, New Mexico}, journal = {Copeia}, volume = {4}, year = {1937}, month = {1937}, pages = {216-222}, abstract = {This report with respect to 27 species of amphibians and reptiles on the Jornada Experimental Range and 7 additional species in Mesilla Valley, Dona Ana County, New Mexico, is based on collections and notes made by the authors as a spare-time project during 1934 and 1935. From 1931 to 1933, the junior author studied individuals of several species. Fourteen of these species have not been reported previously from this county. Thus, the Dona Ana County list is increased to 9 species of amphibians and 34 of reptiles, more than are known in any other county in New Mexico. The authors{\textquoteright} specimen collections of Amyda emoryi and Rana tarahumarae in Mesilla Valley, a part of Rio Grande Valley, are probably the first and second records, respectively, of these two species in this state.The Jornada Experimental Range, where nearly all the authors{\textquoteright} collections were made, has its headquarters 23 miles north of Las Cruces. It is an area of 302 square miles at the southern end of Jornada del{\textquoteright} Muerto, a plain which extends northward for more than 100 miles. Most of the Jornada range is a plain in the Lower Sonoran life zone, varying in elevation from 4,000 to 4,600 feet and without permanent water, except wells and artificial tanks. San Andres Mountains and foothills along the eastern boundary rise in the Upper Sonoran life zone to 8,000 feet and have a few permanent springs, of which Ropes Spring is best known.}, keywords = {amphibians, Jornada Experimental Range, reptiles, specimen collections, study}, url = {/files/bibliography/038.pdf}, author = {E. L. Little Jr. and Keller, J.G.} } @article {52608, title = {After the drought}, journal = {The American Cattle Producer}, volume = {17}, number = {1}, year = {1935}, month = {1935}, pages = {3-5}, abstract = {In the Southwest, rainfall has been deficient ever since 1930; and, as a climax, 1934 was as dray as a lost caravan in the Gobi Desert. In southern New Mexico, the average annual rainfall is about 9 inches; but, in 1934, Jupiter Pluvius failed to function in customary fashion and furnished only a little over half the usual amount. For the first 9 months of 1934, rainfall in several southern New Mexico counties was less than 40 percent of the average, so that forage production on both summer and winter ranges was far below normal. This drought, one of the worst in Southwestern annals, caused severe cattle losses, complicated range management and necessitated emergency supplemental feeding, sacrifice sales, and forced shipments of cattle from the impoverished open range country. Government records show 1934 to be excelled only by the notable drought of 1903-04. What can be done to prevent the regular repetition of the tragedy of drought? Artificial rainmaking has invariably failed. Are there any practical methods of circumventing dry weather and its range-depleting effects? How can Southwestern cattlemen fortify their ranges against ultimate deterioration by both drought and overgrazing? What can be done to increase the stability and improve the economy of cattle grazing in the far-flung Southwest? Suggestions that may be helpful in planning for the future can be obtained by a careful screening of the results from the Jornada Experimental Range located near Las Cruces, New Mexico. Here the U.S. Forest Service has, among other things, studied the minimization of drought losses, the upbuilding of depleted ranges, the determination of grazing capacity, and various systems of grazing as related to range-cattle production.}, keywords = {drought, improve economy, increase stability, prevention, Southwest, tragedy}, url = {/files/bibliography/029.pdf}, author = {R.S. Campbell} } @conference {52611, title = {American egrets at the Jornada Experimental Range, New Mexico}, booktitle = {Condor}, volume = {36}, year = {1934}, month = {1934}, pages = {247}, abstract = {Two migrating American Egrets (Casmerodium albus egretta) were observed at the Jornada Experimental Range near Las Cruces, New Mexico, on April 23, 1934. As this species is not listed in Mrs. F.M. Bailey{\textquoteright}s {\textquotedblleft}Birds of New Mexico,{\textquotedblright} this note is offered as a migration record. Since they probably are becoming more numerous as a result of protection, others doubtless have observed these rare birds previously within the state. These American Egrets remained most of the day around the water tanks at the Headquarters of the Jornada Experimental Range on a desert mesa about 15 miles east of the Rio Grande and attracted the attention of everyone at headquarters. The distinguishing marks of the species--the white plumage, black legs and feet, yellow bill and, on one bird, aigrette plumes--were clearly observed with prism binoculars of 8-diameter magnification at a distance of 125 feet. Pictures were taken at this distance also. The egrets stayed near the tanks with the cattle and were not easily frightened. When approached too closely by people, they would fly to another tank a short distance away. On the morning of October 16, five more egrets on their southward migration were seen at Road Tank, 6 miles northeast of headquarters. In order to be certain these birds were not the smaller Snowy Egret (Egretta thula), the writer examined a specimen of the latter species in the museum of the New Mexico State College of Agriculture and Mechanic Arts. Living Snowy Egrets also were seen at Picacho-Bosque on the Rio Grande near Las Cruces where about 25 pairs nested this year.}, keywords = {American egrets, Jornada Experimental Range, observation}, url = {/files/bibliography/027.pdf}, author = {E. L. Little Jr.} } @article {52617, title = {The assimilations of calcium and phosphorous from different mineral compounds and their effect on range cattle}, year = {1933}, note = {//??//NONE//}, month = {1933}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, calcium,cattle, cattle,nutrients, chapter, chapters, nutrients,cattle, phosphorous,cattle, report, reports}, isbn = {Bulletin 214}, author = {Lantow, J. L.} } @article {52628, title = {Atmospheric electricity during sand storms}, journal = {Science}, volume = {69}, year = {1928}, month = {May 3, 1928}, pages = {474-475}, abstract = {The Jornada Range Reserve, near Las Cruces, NM, is an experiment station maintainedby the U.S. Forest Service for the purpose ofstudying range problems. Since grazing studies areparamount, the station laboratory is not equipped with instruments used to measure electrical energy. However, the article entitled {\textquotedblleft}Electricity from the Air" which appeared intheNewsSupplement of Science, March 30, 1928, brings to mind some very interesting observations that were made recently at the Jornada headquarters. Numerous stories are circulating throughout the region regarding the electrical phenomena that occur during sandstorms. These accounts vary with the personal characteristics of the storyteller. Some versions are no more than drab, conservative statements. Others are displayed in a glamorous setting of colorful phrases and artistic profanity. All of them deal with a near electrocution of some luckless cowboy while placing the coffee pot on the camp stove during a sandstorm or with automobiles becalmed by static under similar climatic conditions. The first tangible proof observed by the writer that these accounts were not without foundation was obtained during a severe storm on April 4, 1928. On the afternoon of that day, the sandstorm reached its peak of violence between 3 and 4 o{\textquoteright}clock in the afternoon. During this time the sky was cloudless. The first evidence of an electrical disturbance was observed in the vacuumtube lightning arrester on the office telephone. Between the carbons of this device, a strong electric arc would form and continue uninterrupted for a period of about 30 seconds. When the arc was broken, it was immediately followed by another arc of the same general character. The radio receiving set was the second object of concern. This instrument is equipped with a 75-ft, multi-strand copper aerial which is elevated about 20 ft above ground. Both the aerial and the telephone wires extend in anorth and south direction, which places them at right angles to the strong west wind. The receiving set was disconnected from the ground and aerial. The tip of the lead-in wire from the radio antenna was placed near the tip of the ground wire. An electric arc resulted immediately. By varying the distance between the wires, it was found that 3.5 centimeters was the maximum width of the gap over which an arc would form. With this arrangement of the wires, the arc was consistent and would continue for a period of 30 seconds without a visible break. When they did occur, the breaks were of short duration. The path of the arc varied in its course between the ground and antenna tips, much after the manner of chain lightning.}, keywords = {atmospheric electricity, electrical disturbance, sandstorms}, url = {/files/bibliography/014.pdf}, author = {Canfield, R.H.} }