@conference {JRN55421, title = {Recently observed trends in surface roughness and wind friction velocity across the southwestern United States}, booktitle = {102nd American Meteorological Society Annual Meeting}, year = {2022}, month = {01/23-27/20}, address = {Houston, Texas}, abstract = {Increasing springtime dust activity reported over the southwestern United States is a risk factor for visibility, air quality, human health, and water resources. The impact on water resources is primarily through a possible shift in the Colorado River basin{\textquoteright}s hydrological cycle due to early springtime snowmelt from dust deposition on mountain snowpack. These risks are likely exacerbated with landcover change across the southwest due to climate change and land use practices. Understanding spatiotemporal trends in indicators of surface roughness (e.g., us*/Uh) and the wind friction velocity at the soil surface (us*) over the different land cover types across the southwest is a first and critical step for understanding the controls on aeolian processes and downwind dust deposition. We apply a recently developed albedo-based drag partition scheme to calculate us*/Uh and us*. We use the 20 year (2001-2020) Moderate Resolution Imaging Spectroradiometer daily albedo (500 m pixel) to calculate us*/Uh. The us*/Uh are multiplied by wind speed (at 10 m height) from GridMet (Gridded Surface Meteorological Dataset: daily at 4 km pixels) to provide us* for the spring months (March-May)-the season of greatest dust activity. These data are harmonized within the Google Earth Engine to provide daily maxima at 500 m and examine how surface roughness (primarily due to vegetation) has changed over the past two decades across the southwest and its relation with increasing dust activity. We performed decadal and trend analyses using the Mann-Kendall trend test which identified spatiotemporal patterns of us*/Uh and us* across the study area within different ecoregions and land cover types. The results enabled the identification and characterization of springtime dust hotspots over the southwestern United States during the last two decades. The dust hotspot trend analysis provided insights needed to predict the future state of the dust activity and its relation with human health, dust on snow, and the hydrological cycle in the Colorado River basin. Importantly, this study also informs how the albedo-based drag partition scheme can improve regional and global dust emission modeling sensitivity to subgrid-scale land cover dynamics. }, keywords = {Air quality, Colorado River basins, dust, observed trends, snowmelt, southwestern United States, surface roughness, wind friction velocity}, author = {Saroj Dhital and Nicholas Webb and A. Chappell and Travis W. Nauman and Danielle Duni and Susan LeGrand and Nathaniel W. Chaney and S. McKenzie Skiles} } @proceedings {JRN55363, title = {Real-time LoRaWAN precision ranching technologies: What we{\textquoteright}ve learned}, year = {2022}, month = {2/8/2022}, abstract = {We tested a precision livestock farming (PLF) system deployed across 4000-ha of Chihuahuan Desert Rangeland (trial 1; T1) and 130-ha of wheat pasture (trial 2; T2) over three (March-May 2020) and one month (October 2020), respectively. The PLF system included a LoRa WAN Kerlink{\textregistered} iStation gateway, deployed either using solar power and WiFi Backhaul communication or off-grid power and Ethernet connection. Tested sensors were Abeeway{\textregistered} Industrial trackers (IT) and Decentlab{\textregistered} sensors to monitor precipitation and water level in a cattle drinking trough. In T1, the battery power of IT deployed on beef cattle (n = 43) dropped from 100 to ~35\% over the three-month trial and GPS data packets programmed to be recorded at 15-min intervals were recovered at ~0.08 {\textendash} 1.3-hour intervals yielding between 46 to 80\% of expected GPS fixes. Variation in GPS data acquisition was associated with distance to the gateway base station and oscillations in solar power and backhaul WiFi signal. In T2, stationary IT deployed either indoors (n = 5) or outdoors (n = 6) were programmed to collect GPS locations and acceleration data at 1-min and 15-min intervals, respectively. More frequent and reliable GPS data packet acquisition was recorded with IT deployed outdoors (in T2; bias = 5.20 m) compared to IT deployed indoors (in T2; bias = 17.76 m) and those deployed in T1. Except for a few cases of background noise, accelerometer data were almost non-existent due to the static deployment of IT in T2 (powersaving function). Results from our case studies suggest the feasibility of mounting a fully operational LoRaWAN system for PLF on extensive rangelands. Our studies also identified areas for improvement of LoRa WAN infrastructure and data communication, analysis and visualization to further enhance uses of real-time biosensing of animals and monitoring of ranching infrastructure in commercial PLF applications. }, keywords = {LoRaWAN, precision ranching, Real-time, technologies}, author = {S. Nyamuryekung{\textquoteright}e and Andr{\'e}s F. Cibils and S. A. Utsumi and Richard E. Estell and Andrew Cox and Danielle Duni and V. Gouvea and Carolina Brandani and G. Duff and Qixu Gong and Tony Waterhouse and J P Holland and Huiping Cao and LE Boucheron and H. Chen and S. Spiegal} } @article {JRN55393, title = {Rangeland degradation in Mongolia: A systematic review of the evidence}, journal = {Journal of Arid Environments}, volume = {196}, year = {2022}, month = {01/2022}, pages = {104654}, abstract = {Rangeland degradation compromises the functioning of extensive natural ecosystems and threatens pastoral livelihoods worldwide. Yet, defining rangeland degradation and its underlying causes remains controversial. In this study we review rangeland studies to identify different approaches used to assess rangeland degradation in Mongolia, where the prevalence of degradation is frequently referenced in media and policy documents. We compiled studies addressing rangeland degradation, with a special emphasis on the grey literature, to assess: 1) how different studies defined and quantified rangeland degradation; 2) whether a theoretical background was explicitly mentioned; 3) which drivers of degradation were identified and whether their effects were quantified; and 4) the distribution of the studies across relevant environmental gradients. We found 114 studies published between 1950 and 2021. Degradation was frequently assessed as a change in vegetation or land cover, but there was no standard definition of rangeland degradation and only a few studies explicitly defined contrasting degradation levels (19 studies). Less than one third of studies (27) referred to a theoretical framework. Grazing and climate (precipitation and temperature), alone or in combination, were most frequently mentioned as drivers of degradation but the impact of different drivers differed across ecological zones. The majority of studies were conducted in the steppe, forest steppe and desert steppe zones of central Mongolia. Future studies should consider the differences in ecological potential of each rangeland and quantify the relative importance of different drivers in each ecological zone. Emerging initiatives for rangeland assessment and monitoring that use long-term data collection following standardized methodologies based on robust theoretical frameworks hold promise for the design of policies and strategies for sustainable land use in Mongolia.}, keywords = {land degradation, overgrazing, sustainable land management}, doi = {10.1016/j.jaridenv.2021.104654}, url = {files/bibliography/22-018.pdf}, author = {Sumjidmaa Sainnemekh and Isabel C. Barrio and Bulgamaa Densambuu and Brandon T Bestelmeyer and {\'A}sa L. Arad{\'o}ttir} } @article {JRN55383, title = {Recycling nutrients in the beef supply chain through circular manuresheds: Data to assess tradeoffs}, journal = {Journal of Environmental Quality}, year = {2022}, month = {5/14/2022}, abstract = {Nutrient circularity can help supply chain managers meet sustainability goals. Across the segmented beef supply chain, opportunity exists to reinforce and introduce nutrient circularity by recycling surplus manure nutrients from feedlots to feed-producing lands. We describe four datasets developed to evaluate options in U.S. and Canadian beef systems. The datasets delineate three {\textquotedblleft}circular manuresheds{\textquotedblright}, each encompassing a hay-grazing landscape where beef cattle are raised on grazingland with hay grown nearby, and the distant feedlots where those cattle produce manure nutrients for potential import back to the hayfields. We selected the hay-grazing landscapes of New Mexico, USA; Florida, USA; and western Canada (the assemblage of Manitoba, Saskatchewan, Alberta, British Columbia) because of their significant grazingland production and potential to substitute feedlot manure for commercial fertilizer on hayfields. In each circular manureshed, the manure nutrients from major feedlot destinations could supply a considerable proportion of the P used by hay for grazing cattle: 34\% of the P requirements in New Mexico; 36\% in Florida, and 6\% in western Canada. The average distance to return the resource was 647 km for New Mexico, 1884 km for Florida, and 1587 km for western Canada. These magnitudes and distances suggest that the New Mexico circular manureshed may be the most economically viable in the current agri-food system, but this reflects only part of a greater assessment of tradeoffs. The circular manureshed concept provides a platform for simultaneous consideration of competing factors for sustainability via circularity.}, keywords = {beef supply chains, Manuresheds, Nutrient circularity, Recycling, Supply chain management}, doi = {10.1002/jeq2.20365}, url = {files/bibliography/22-012.pdf}, author = {S. Spiegal and Jo{\~a}o M.B. Vendramini and S. Bittman and Maria Silveira and Craig Gifford and C. A. Rotz and John P Ragosta and Peter J. A. Kleinman} } @article {JRN55276, title = {Regional ensemble modeling reduces uncertainty for digital soil mapping}, journal = {Geoderma}, volume = {397}, year = {2021}, month = {09/01/2021}, pages = {114998}, abstract = {Recent country and continental-scale digital soil mapping efforts have used a single model to predict soil properties across large regions. However, different ecophysiographic regions within large-extent areas are likely to have different soil-landscape relationships so models built specifically for these regions may more accurately capture these relationships relative to a {\textquoteleft}global{\textquoteright} model. We ask the question: Is a single {\textquoteleft}global{\textquoteright} model sufficient or are regionally-specific models useful for accurate digital soil mapping? We test this question by modeling soil depth classes across the 432,000 km2 upper Colorado River Basin in the Western USA using a single global model, multiple ecophysiographic models, and ensembles of the ecophysiographic models. Effective soil depth class observations (n = 12,194) were derived from multiple soil databases. Fifty-seven environmental covariates were derived from a 30 m digital elevation model, climate data, satellite imagery, and aeroradiometric data. Three independent land classifications were used to stratify the area. Two expert-derived land classifications, USDA Major Land Resource Areas (MLRA) and US-EPA Level III ecoregions, divided the study area into multiple ecophysiographic regions based on vegetation and broad-scale physiographic differences. The third land classification divided the study area into broad landforms. Soil depth observations were split into separate training (n = 10,470) and validation (n = 1,724) datasets. First, a {\textquoteleft}global{\textquoteright} random forest model was used to model soil depth classes using all training observations and covariates. {\textquoteleft}Global{\textquoteright} denotes a model built with all training data across the extent of the area, not a model at world extent. Second, the land classifications were used to subset the observations into ecophysiographic sub-datasets and random forest models were refit for each region. Models fit by ecophysiographic region are referred to as regional models. Thirdly, predictions from each regional model were fused into regional-ensemble models. Accuracy, Brier scores, and Shannon{\textquoteright}s entropy were used to compare model accuracy and uncertainty. Regional ecophysiographic models were also compared to models built for geographic areas that were defined solely to be approximately equal in area. Training dataset density and the imbalance ratio were investigated to determine if data characteristics influenced regional accuracy/uncertainty metrics. Accuracy for the global model using the validation set was 62.8\%. Regional model accuracies ranged between 56.1\% and 75.0\%. We found: 1) useful inter-regional differences in global model accuracy were revealed when the global model was validated by region, 2) no consistent relationship between training observation density and accuracy/uncertainty metrics, 3) no meaningful differences in accuracy and uncertainty metrics between physiographic and geographic regions, 4) ensembles of regionally-specific models were approximately as accurate as global models, and 5) both region-specific models and ensembles of regional models were less uncertain than the global model. Overall, we recommend the use of soil depth class predictions made from MLRA regional ensemble models because this prediction had higher accuracy than the ecoregion ensemble model prediction, but lower uncertainty than both the global model and the landform ensemble model predictions. We answer our question: Ensembles of regionally-specific models are approximately as accurate as global models, but result in less uncertainty.}, keywords = {ecoregions, Landforms, machine learning, Major land resource areas, Regionalization, soil survey}, doi = {10.1016/j.geoderma.2021.114998}, url = {files/bibliography/21-009.pdf}, author = {Colby Brungard and Travis Nauman and Danielle Duni and Kari Veblen and Kyle Nehring and David A. White II and S. W. Salley and Julius Anchang} } @article {JRN55320, title = {Review of Vesicular Stomatitis in the United States with Focus on 2019 and 2020 Outbreaks}, journal = { Pathogens }, volume = {10}, year = {2021}, month = {8-6-2021}, pages = {993}, abstract = {Vesicular stomatitis (VS) is a vector-borne livestock disease caused by vesicular stomatitis New Jersey virus (VSNJV) or vesicular stomatitis Indiana virus (VSIV). The disease circulates endemically in northern South America, Central America, and Mexico and only occasionally causes outbreaks in the United States. Over the past 20 years, VSNJV outbreaks in the southwestern and Rocky Mountain regions occurred with incursion years followed by virus overwintering and subsequent expansion outbreak years. Regulatory response by animal health officials is deployed to prevent spread from lesioned animals. The 2019 VS incursion was the largest in 40 years, lasting from June to December 2019 with 1144 VS-affected premises in 111 counties in eight states (Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas, Utah, and Wyoming) and was VSIV serotype, last isolated in 1998. A subsequent expansion occurred from April to October 2020 with 326 VS affected premises in 70 counties in eight states (Arizona, Arkansas, Kansas, Missouri, Nebraska, New Mexico, Oklahoma, and Texas). The primary serotype in 2020 was VSIV, but a separate incursion of VSNJV occurred in south Texas. Summary characteristics of the outbreaks are presented along with VSV-vector sampling results and phylogenetic analysis of VSIV isolates providing evidence of virus overwintering.}, keywords = {equine; livestock disease; vector-borne disease outbreak; vesicular stomatitis}, doi = {10.3390/pathogens10080993 }, url = {files/bibliography/21-034.pdf}, author = {Angela Pelzel-McCluskey and Brad Christensen and John Humphreys and Miranda Bertram and Robert Keener and Robert Ewing and Lee W Cohnstaedt and Rachel Tell and Debra C. Peters and Luis L Rodriguez} } @article {JRN55207, title = {Rating fire danger from the ground up}, journal = {GeoHealth}, volume = {100}, year = {2020}, month = {12/2019}, abstract = {Better soil moisture information with spatial and temporal resolutions relevant for assessing fuel bed conditions and wildfire probability offers promise for improving fire danger ratings. Wildfires consumed more than 3.5 million hectares in the United States in 2018 and federal fire suppression costs topped $3 billion USD. These fires took a severe toll on many communities, resulting in the destruction of more than 18,000 residences and the deaths of more than 100 people. Wildfire damages like these are a threat in many nations, and researchers from across the globe, and across multiple scientific disciplines, are working to improve fire danger rating systems to help protect natural resources and human health and safety. One new concept emerging as a valuable contribution to this effort is the integration of soil moisture information as a predictor of wildfire probability. Soil moisture, particularly within the root zone, is a key link between weather conditions, such as precipitation and temperature, and the characteristics of the live vegetative {\textquotedblleft}fuel bed{\textquotedblright}, such as fuel moisture and fuel loads. These dynamic vegetation characteristics strongly influence wildfire probability and can be challenging to model and monitor at relevant spatial and temporal scales using field data or optical remote sensing of fuel moisture (e.g., remote sensing live fuel moisture models contain relatively large margins of error that varies by vegetation type). Soil moisture monitoring capabilities, in contrast, have been steadily growing due to the development of in situ networks and dedicated satellites. While the relationships between soil moisture, fuel conditions, and wildfire occurrence have long been intuitively understood, the increasing availability of soil moisture information is creating significant opportunities to quantify these relationships and incorporate them into new or existing weather-based fuel moisture models and fire danger rating systems.}, doi = {https://doi.org/10.1029/2019EO137858}, url = {files/bibliography/20-015.pdf}, author = {Matthew Levi and Krueger, Erik and Snitker, Grant J and Ochsner, Tyson and Miguel L Villarreal and Emile H. Elias and Dannele E. Peck} } @article {JRN55234, title = {Rapid bulk density measurement using mobile device photogrammetry}, journal = {Soil Science Society of America Journal}, volume = {84}, year = {2020}, month = {May 2020}, pages = {811-817}, chapter = {811}, abstract = {Soil bulk density (Db), the ratio of soil solid mass to bulk soil volume, is an important but difficult soil property to measure. Existing methods are either expensive, time consuming, or destructive to the sample. The goal of this research was to investigate the utility of photogrammetry for measuring Db. Photogrammetry is the determination of shape and volume from multiple overlapping photos. Photos of soil peds placed on a 3D-printed turntable were obtained using two mobile devices. Photogrammetrymeasured volume and Db were compared with volume and Db measured using the clod and 3D laser-scanning methods. No significant differences between Db measured by any method were found. No statistical difference between cameras types was found. We conclude that photogrammetry is a useful method for measuring Db. Measuring Db using photogrammetry was much easier than the other methods and was less expensive and faster than 3D laser scanning.}, doi = {https://doi.org/10.1002/saj2.20063}, url = {files/bibliography/20-031.pdf}, author = {Whiting, Michael and S. W. Salley and D. K. James and Jason W. Karl and Colby Brungard} } @conference {JRN54999, title = {Rapid Soil and Ecological Site Identification and Vegetation Monitoring Using the LandPKS App and EDIT}, booktitle = {72nd Society for Range Management International Meeting}, year = {2019}, month = {02/2019}, publisher = {Society for Range Management Meeting Abstracts}, organization = {Society for Range Management Meeting Abstracts}, address = {Minneapolis, Minnesota}, abstract = {

There has been significant progress in standardizing rangeland inventory and monitoring methods in the past 20 years. Improved ecological site descriptions (ESDs) provide access to a wealth of information that can be used to optimize management. The protocols have been adopted by the NRCS and BLM, resulting in large datasets that are increasingly analyzed to improve ESDs. This {\textquotedblleft}big data{\textquotedblright} could also be used to interpret ranch-level monitoring results. Multiple indicators can be generated from these datasets, addressing a variety of objectives including livestock production, soil and water conservation, and wildlife habitat restoration. The vast majority of landowners and managers, however, are neither applying the standardized protocols nor accessing ESDs because the protocols require too much time, data storage and analysis are too complicated, and it{\textquoteright}s too difficult to identify ecological sites. We will provide an overview of a pair of new tools that address these challenges. LandPKS (Land-Potential Knowledge System) is a free mobile app that includes the following functions: (1) guided soil profile description that is used by embedded algorithms to (2) predict the soil and ecological site and (3) link to basic ecological site information in EDIT (Ecological Data Interpretation Tool). EDIT provides (4) the ability to independently identify ecological sites using embedded keys, (5) the information formerly available through ESIS in a much more user-friendly and interactive format, and (6) tools for entering and updating ecological site information. LandPKS also includes a {\textquotedblleft}LandCover{\textquotedblright} module that allows landowners and managers to (7) collect vegetation cover data compatible with the data collected by NRCS and BLM, and (8) automatically calculates indicators and backs up the data in the cloud. By late 2019 it will also allow users to compare their data with anonymized data from the large NRCS and BLM datasets for land with similar potential.

}, author = {Jeffrey E. Herrick and Brandon T Bestelmeyer and Joel R. Brown and Lepak, Dominika and Rachel Murph and Amy Quandt and Rizza, John and Curtis Talbot and Jebediah C. Williamson} } @conference {JRN54991, title = {The Restore New Mexico Collaborative Monitoring Program: The action and the science}, booktitle = {72nd Society for Range Management International Meeting}, year = {2019}, month = {02/2019}, publisher = {Society for Range Management Meeting Abstracts}, organization = {Society for Range Management Meeting Abstracts}, address = {Minneapolis, Minnesota}, abstract = {

Restoration treatments to reduce shrub cover and increase grass cover have a long history in the Chihuahuan Desert region of southwest New Mexico. Brush management treatments on Bureau of Land Management (BLM) land became common in the 1980s, but with very little monitoring to evaluate restoration outcomes. The Restore New Mexico program was initiated in 2005 to accelerate brush management and other restoration applications through a partnership of the BLM, Natural Resources Conservation Service, Soil and Water Conservation Districts, and wildlife-oriented non-governmental organizations. There was also increased interest in monitoring to: 1) estimate the effects of brush management treatments on vegetation; 2) identify environmental factors explaining variations in treatment outcomes; and 3) determine which brush management treatments are not performing as expected and identify strategies to maximize future benefits (adaptive management). BLM staff reached out to the USDA-ARS Jornada Experimental Range in 2006 for assistance with tools to design restoration treatments based on existing knowledge (ecological site descriptions and mapping) and to embed monitoring experiments featuring paired treated and untreated plots within treatment areas. From 5-10 years of monitoring data have been analyzed in 39 areas spanning millions of acres. Analyses and interpretations were initially developed with BLM and presented and refined with a broader coordination group. Care was taken to allow explanations for trends to emerge from the group setting, rather than to present them outright. The data provided a complicated \“report card\” on restoration practices \– confirming some hypotheses, finding little support for others, and raising new questions. We will discuss how these scientific interpretations will be used in the management of past restoration investments and the development of future restoration efforts.

}, author = {Leticia Lister and Brandon T Bestelmeyer} } @inbook {JRN55148, title = {Rangeland Livestock Production in North America}, booktitle = {Livestock Production, Management, Strategies and Challnges}, year = {2019}, publisher = {Nova Science Publishers}, organization = {Nova Science Publishers}, chapter = {6}, address = {Hauppauge, NY}, abstract = {

Rangelands of North America vary greatly across their one billion hectares, but a cultural legacy of livestock and their tenders unifies the realm. From the cowhand in Canada to the buckaroo of the United States to the charro or vaquero of Mexico, land-based livestock producers hold a place in the hearts and minds of North Americans. As of 2014, the continent supported some 134 million cows, 15 million sheep, and 11 million goats. Considerable numbers are produced solely on grains, hay, silage, irrigated pasture, and agricultural by-products, but rangelands also play an important role in North American livestock production, with their use varying regionally, temporally, and with the operator{\textquoteright}s level in the livestock production chain. For each country, we summarize livestock inventories, production approaches, and land tenure, along with the major problems faced by producers and the innovative solutions they are exploring. We close with a brief discussion of how the three nations are linked through imports and exports.

}, author = {S. Spiegal and Lynn Huntsinger and Paul F. Starrs and Tracy Hruska and Michael P. Schellenberg and Matthew M. McIntosh} } @conference {JRN55066, title = {Recent streamflow declines and snow drought in the Upper Rio Grande tributary basins}, booktitle = {Universities Council on Water Resources}, year = {2019}, month = {06/2019}, address = {Snowbird, UT}, abstract = {

To understand how future climate change will impact agricultural communities in the southwest, it is essential that we know how water availability has varied in the past. Over the last half century, there has been a trend of declining streamflow across the southwestern United States. For rivers such as the Rio Grande, with more than 65\% of the native flow originating as snowpack in mountainous headwaters, this trend has been driven by changes in winter precipitation, decreasing snow water equivalent (SWE), rising temperatures and earlier spring snowmelt. Researchers have already documented how lower SWE contributes to reduced streamflow volume from the entire Upper Rio Grande (URG) headwaters to the state line between Colorado and New Mexico. In this paper, we analyze the relationship between SWE and streamflow volume over the last 30 - 40 years at a finer spatial scale, looking at individual high elevation watersheds in New Mexico that contain tributaries of the Rio Grande. In addition, we use longer term datasets to identify years of snow drought that resulted from significantly lower winter precipitation. Two years of critically low snowpack (2002 and 2018) provide insights into potential future snow drought scenarios. We intend to use these findings to summarize potential impacts from climate change on the rural, acequia communities who live in and cultivate the narrow valleys situated just below the high elevation watersheds.

}, author = {Caitriana Steele and Emile H. Elias and J.T. Reyes} } @article {JRN55094, title = {Reducing sampling uncertainty in aeolian research to improve change detection}, journal = {Journal of Geophysical Research}, volume = {124}, year = {2019}, month = {04/2019}, pages = {1-12}, chapter = {1}, abstract = {

Measurements of aeolian sediment transport support our understanding of the process mechanics, dust model parameterization, and assessments of the sensitivity of the dust cycle to environmental change. However, sample design principles are often overlooked in aeolian research. Here, we use high-density measurements of sediment mass flux across land use and land cover types to examine sample size and power effects on detecting change in aeolian transport. Spatial variances accounted for 5\% to 45\% of total with-in site variances in aeolian transport. Differences in transport were detectable for \<20\% of comparisons at sites with large spatial variability. Failure to detect change with intensive sampling suggests that aeolian research is very likely to be much more uncertain than recognized. We show small and selective sampling, common in aeolian research, gives the false impression that differences in aeolian transport can be detected, potentially undermining inferences about process and impacting reproducibility of aeolian research.

}, doi = {doi.org/10.1029/2019JF005042}, url = {files/bibliography/19-010.pdf}, author = {Nicholas Webb and A. Chappell and Brandon Edwards and Sarah McCord and Justin Van Zee and Brad Cooper and Ericha Courtright and Danielle Duni and Brenton Sharrat and Negussie Tedela} } @proceedings {JRN55167, title = {Resilient agroecosystems session}, year = {2018}, month = {12/14/2018}, abstract = {

Assessing vulnerability of agricultural systems to climate variability and change is vital in securing food systems and sustaining rural livelihoods. Farmers, ranchers, and forest landowners rely on science-based, decision-relevant, and localized information to maintain production, ecological viability, and economic returns. This contribution synthesizes a collection of research on the future of agricultural production in the American Southwest (SW). Research was based on a variety of geospatial methodologies and datasets to assess the vulnerability of rangelands and livestock, field crops, specialty crops, and forests in the SW to climate-risk and change. This collection emerged from the development of regional vulnerability assessments for agricultural climate-risk by the U.S. Department of Agriculture (USDA) Climate Hub Network, established to deliver science-based information and technologies to enable climate-informed decision-making.\  Authors defined vulnerability differently based on their agricultural system of interest, although each primarily focuses on biophysical systems. We found that an inconsistent framework for vulnerability and climate risk was necessary to adequately capture the diversity, variability, and heterogeneity of SW landscapes, peoples, and agriculture.\  Through the diversity of research questions and methodologies, this collection of articles provides valuable information on various aspects of SW vulnerability. All articles relied on geographic information systems technology, with highly variable levels of complexity. Agricultural articles used National Agricultural Statistics Service data, either as tabular county level summaries or through the CropScape cropland raster datasets. Most relied on modeled historic and future climate information, but with differing assumptions regarding spatial resolution and temporal framework. We assert that it is essential to evaluate climate risk using a variety of complementary methodologies and perspectives. In addition, we found that spatial analysis supports informed adaptation, within and outside the SW United States. The persistence and adaptive capacity of agriculture in the water-limited Southwest serves as an instructive example and may offer solutions to reduce future climate risk.

}, author = {Emile H. Elias and J.T. Reyes and Caitriana Steele and Johnson, R. and Rachel Steele} } @article {JRN54889, title = {Resolving dust emission responses to land cover change using an ecological land classification}, journal = {Aeolian Research}, volume = {32:141-153}, year = {2018}, month = {03/2018}, abstract = {

Despite efforts to quantify the impacts of land cover change on wind erosion, assessment uncertainty remains large. We address this uncertainty by evaluating the application of ecological site concepts and state-and-transition models (STMs) for detecting and quantitatively describing the impacts of land cover change on wind erosion. We apply a dust emission model over a rangeland study area in the northern Chihuahuan Desert, New Mexico, USA, and evaluate spatiotemporal patterns of modelled horizontal sediment mass flux and dust emission in the context of ecological sites and their vegetation states; representing a diversity of land cover types. Our results demonstrate how the impacts of land cover change on dust emission can be quantified, compared across land cover classes, and interpreted in the context of an ecological model that encapsulates land management intensity and change. Results also reveal the importance of established weaknesses in the dust model soil characterisation and drag partition scheme, which were largely insensitive to the impacts of land cover change. New models that address these weaknesses, coupled with ecological site concepts and field measurements across land cover types, could significantly reduce assessment uncertainties and provide opportunities for identifying land management options.

}, doi = {10.1016/j.aeolia.2018.03.001}, url = {files/bibliography/18-004.pdf}, author = {Magda Galloza and Nicholas Webb and M. Bleiweiss and Craig Winters and Jeffrey E. Herrick and E.L. Ayers} } @article {JRN54907, title = {Regional grassland productivity responses to precipitation during multiyear above- and below-average rainfall periods}, journal = {Global Change Biology}, volume = {24:1935-1951}, year = {2018}, month = {05/2018}, abstract = {

There is considerable uncertainty in the magnitude and direction of changes in precipitation associated with climate change, and ecosystem responses are also uncertain. Multiyear periods of above- and below-average rainfall may foretell consequences of changes in rainfall regime. We compiled long-term aboveground net primary productivity (ANPP) and precipitation (PPT) data for eight North American grasslands, and quantified relationships between ANPP and PPT at each site, and in 1-3 year periods of above- and below-average rainfall for mesic, semiarid cool, and semiarid warm grassland types. Our objective was to improve understanding of ANPP dynamics associated with changing climatic conditions by contrasting PPT-ANPP relationships in above- and below-average PPT years to those that occurred during sequences of multiple above- and below-average years. We found differences in PPT-ANPP relationships in above- and below-average years compared to long-term site averages, and variation in ANPP not explained by PPT totals that likely are attributed to legacy effects. The correlation between ANPP and current- and prior-year conditions changed from year to year throughout multiyear periods, with some legacy effects declining, and new responses emerging. Thus, ANPP in a given year was influenced by sequences of conditions that varied across grassland types and climates. Most importantly, the influence of prior-year ANPP often increased with the length of multiyear periods, whereas the influence of the amount of current-year PPT declined. Although the mechanisms by which a directional change in the frequency of above- and below-average years imposes a persistent change in grassland ANPP require further investigation, our results emphasize the importance of legacy effects on productivity for sequences of above- vs. below-average years, and illustrate the utility of long-term data to examine these patterns.

}, doi = {10.1111/gcb.14024}, url = {files/bibliography/18-012_0.pdf}, author = {Matthew D. Petrie and Debra C. Peters and Jin Yao and John M Blair and N. Dylan Burruss and S.L. Collins and J. D. Derner and Laureano A. Gherardi and John Hendrickson and O. E. Sala and Paul F. Starrs and Jean Steiner} } @conference {JRN54910, title = {Regional telecoupling and impacts of wet periods across the Chihuahuan Desert of the United States and northern Mexico}, 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 = {

Telecoupling of environmental and ecological conditions in aridlands is associated with the Land Surface Template (LST) and precipitation (PPT) patterns. Variation in telecoupling may be shaped by multiple factors, and local (\< 1 km2) observations may be similar to regional (\> 250 km2) patterns under some conditions and different under others. For example, extreme drought events can influence vegetation over large regions, and overwhelm the effects of many LST factors. Multi-year high PPT periods that resulted in perennial grass production on some sites have received less attention. In the Chihuahuan Desert region, individual rainfall events in the monsoon season are stochastic, suggesting that high PPT is localized and widespread positive telecoupling is improbable. Yet, multi-year high PPT periods may homogenize stochastic rainfall patterns through time and across space to overwhelm local LST conditions, and in this way promote positive telecoupling that is not possible in single years.

Using remote sensing data from 1983-present and a suite of harmonized LST datasets, we sought to quantify telecoupling beginning locally at the Jornada LTER site in New Mexico and expanding to the Chihuahuan Desert in the US and northern Mexico. Our goal was to determine if patterns in climate are coupled to patterns in vegetation response during a wet period or if local heterogeneity in soils and land use decouple climate and vegetation response. We hypothesized that high PPT would aggregate through time to become more regionally-similar and/or more probable, and that increasing duration of a local forcing event at JRN would increase its similarity to the larger region. Our results show that telecoupling in this region is instigated by the aggregation of sustained high PPT and/or extreme high PPT events through time, but its pattern within the rainfall area is contingent on local factors. Wet periods are changing and will play an important role in shaping the future pattern and dynamics of aridlands. By identifying and quantifying patterns in telecoupling, we develop new insight on how climate and landscapes interact, and how these landscapes may respond to future climates.

}, author = {Matthew D. Petrie and Debra C. Peters and N. Dylan Burruss and W Ji and Niall Hanan and Heather Savoy} } @proceedings {JRN54915, title = {Relationships among snow depth, snow water equivalent, streamflow and virus activity in two Colorado watersheds (2004 to 2016)}, volume = {Vesicular stomatitis (VS) is the most common viral vesicular disease affecting livestock (horses, cattle, pigs) throughout the A}, year = {2018}, month = {04/2018}, publisher = {Western Snow Conference}, address = {Albuquerque, NM}, abstract = {

Vesicular stomatitis (VS) is the most common viral vesicular disease affecting livestock (horses, cattle, pigs) throughout the Americas. VS is a vector-borne disease with more than \>1500 incidents of VS infected equine premises in the western US from 2004-2016. \ The ecology of the host-vector-virus-environment system is the subject of a large, collaborative USDA research effort. Initial findings indicate VS incidents were spatially distributed near the stream network and temporally related to streamflow conditions with all first incidents (n=35) occurring following peak annual streamflow. These spatial and temporal relationships showcase the importance of hydrological contributions to the emergence and distribution of VS and indicate that snow conditions may play an important role in VS emergence. Peters et al (2017) report that VS infected premises can be evaluated based upon outbreak (2004, 2014) and expansion (2005, 2015) years. Here we evaluate the relationships between monthly snow depth, snow water equivalent, streamflow and the number of VSV infected equine premises in two watersheds (Big Thompson and Saint Vrain) with a high number VS infected premises. The water content of snowpack and snow depth within both watersheds the months prior to a VS outbreak were both lower (2004) and higher (2014) than years with no infected premises. Conversely, outbreak years had higher autumnal and late season monthly streamflow than years with few or no VS infected premises. The complex water management system of reservoirs and irrigation canals along the Front Range of Colorado and VS vectors may buffer the relationship between SWE, snow depth and virus transmission observed in other locations. More detailed analyses of water conveyance associated with VS infection is needed in these watersheds to evaluate the impacts of local water conditions on the vector-host relationship, particularly related to observed elevated autumnal and summer streamflow co-occurring during outbreak years.

}, author = {Ward, Dustin and Emile H. Elias and Debra C. Peters and Angela Pelzel-McCluskey and J. D. Derner and David McVey and Luis L Rodriguez} } @proceedings {JRN54681, title = {The rangeland management and soil health connection}, year = {2017}, month = {01//2017}, address = {St. George, UT.}, abstract = {
Soil health is defined as the capacity of soil to function and provide ecosystem services to society. \ The importance of managing for the improvement and maintenance of soil health transcends political boundaries, generations, societies and languages. \ The challenge of communicating soil health concepts and motivating action lies in the incredible complexity of soil types, land uses, management practices and ecosystem services. \ Developing and implementing a successful institutional soil health effort requires credible approaches to determine baseline conditions, accurately measure change over management-relevant time, identify threats and establish relationships to human and natural drivers. \ While soil health indicators are a valuable addition to the assessment of rangelands, they are merely one of several necessary attributes required to develop a true picture. \ Developing and applying indicators of soil health (or any indicator) on rangelands is entirely context dependent. \ That context is provided by Ecological Sites and is organized, interpreted and communicated via Ecological Site Descriptions (particularly State and Transition Models). \ This approach will allow us to develop a protocol for the site specific assessment of the economic value of soil health improvement.\ 
}, author = {Joel R. Brown and Jeffrey E. Herrick} } @conference {JRN54814, title = {Regional services in a research context: USDA Climate Hubs in the Agricultural Research Service}, booktitle = {ASA-CSSA-SSSA Annual Meeting}, year = {2017}, month = {10/2017}, publisher = {ASA-CSSA-SSSA Annual Meeting Abstracts}, organization = {ASA-CSSA-SSSA Annual Meeting Abstracts}, address = {Tampa, FL}, abstract = {

Ten USDA Climate Hubs were created in 2014 to develop and deliver science-based, region-specific information and technologies to better enable agricultural decision-making and management to promote resilient working landscapes. Of these ten Hubs, half are administered by USDA{\textquoteright}s Agricultural Research Service (ARS), an agency with historical excellence in science but less so in services. The ARS Hubs therefore represent an innovative opportunity for ARS to enhance its mission through the delivery of user-inspired science at regional scales. The focus of this study is the line connecting science to services within ARS, with an emphasis in three areas: (a) understanding science priorities within the agency and their translation to regional scales; (b) understanding regional user information needs and the capabilities and mechanisms available to respond to those needs; and (c) highlighting success stories from each of the five ARS Hubs in connecting science to users through services delivery. Opportunities and recommendations to continue strengthening the science-to-services linkage are also addressed, including greater incorporation of both physical and social science perspectives, knowledge coproduction and the role of key partner organizations in the regional climate services enterprise.

}, author = {Emile H. Elias and David A. Brown and Ostoja, Steven and Dannele E. Peck and Todey, Dennis and A. Rango} } @proceedings {JRN54677, title = {The role of data and inference in the development and application of ecological site concepts and state-and-transition models}, volume = {Jan 29 - Feb 02, 2017}, year = {2017}, month = {01/2017}, address = {Saint George, Utah}, abstract = {
Information embodied in ecological site descriptions and their state-and-transition models is crucial to effective land management, and as such is needed now. There is not time (or money) to employ a traditional research-based approach (i.e., inductive/deductive, hypothesis driven inference) to addressing the unknowns in developing and documenting ecological site concepts. We propose that the development of ecological site products is a dynamic task of defining concepts and processes that best explain the available data (i.e., abductive reasoning), and as such a more iterative approach to their development is needed than is currently used. Under the proposed approach, ecological site concepts are never viewed as final, but only the best representation that is supported by available knowledge and data. The natural result of this way of thinking is that products like ESDs and STMs should continually be tested and improved as new data become available.
}, author = {Jason W. Karl and Curtis Talbot} } @article {JRN54698, title = {Rehabilitation of community-owned, mixed-use rangelands: Lessons from the Ewaso ecosystem in Kenya}, journal = {Plant Ecology}, volume = {218:23-37}, year = {2017}, month = {02/2017}, abstract = {

Globally, 10-20\% of arid and semi-arid rangelands have been classified as severely degraded (UNCCD 1994; MEA 2005), and in sub-Saharan Africa specifically, 70\% of rangelands are considered moderately to severely degraded (Dregne 1992; UNCCD 1994). Given that these drylands make up 43\% of Africa{\textquoteright}s land area and support approximately 45\% of its population, restoring, maintaining and even increasing their productivity is imperative from both conservation and food security standpoints. In the Laikipia and Samburu counties of North Central Kenya, degradation manifests itself through the increase of bare ground and the replacement of perennial grasses by undesirable plant species, primarily Acacia reficiens and Opuntia stricta, resulting in reduced forage availability. Further complicating management options is the fact that most land in this ecosystem is owned by community conservancies, where the land is managed to support both wildlife and livestock grazing. There has been considerable effort targeted towards using mechanical clearing coupled with reseeding to combat A. reficiens spread. Additionally, the use of both traditional and modern mobile cattle enclosures (commonly referred to as bomas) to initiate autogenic restoration has had an impact on creating vegetation patches in areas with increasing bare ground. Here, we look at the challenges faced in implementing these interventions, as well as the successes and opportunities associated with them.

}, doi = {10.1007/s11258-016-0691-9}, url = {files/bibliography/17-002.pdf}, author = {D.W. Kimiti and Hodge, A.M.C. and Jeffrey E. Herrick and Beh, Adam and Laurie Abbott} } @inbook {JRN54687, title = {Rangeland ecosystem services: nature{\textquoteright}s supply and humans{\textquoteright} demand}, booktitle = {Rangeland Systems: Processes, Management and Challenges}, year = {2017}, pages = {467-489}, publisher = {Springer}, organization = {Springer}, chapter = {14}, address = {New York}, abstract = {

Ecosystem services are the benefits that society receives from nature and they include the regulation of climate, the pollination of crops, the provisioning of intellectual inspiration and recreational environment, as well as many essential goods such as food, fiber, and wood. Rangeland ecosystem services are often valued differently by different stakeholders interested in livestock production, water quality and quantity, biodiversity conservation, or carbon sequestration. The supply of ecosystem services depends on biophysical conditions and land use history and it is assessed using surveys of soils, plants and animals. The demand for ecosystem services depends on educational level, income and location of residence; and it is assessed with stakeholder interviews and questionnaires/surveys. Rangeland management affects the supply of different ecosystem services by producing tradeoffs among services. Tradeoffs result when an increase in one service is associated with a decline in another and win-win situations occur when an increase in one service is associated with an increase in other services. This chapter provides a conceptual framework in which range management decisions are seen as a challenge of reconciling supply and demand of ecosystem services.

}, keywords = {cultural, ecosystem services, human well-being, provisioning, regulation, stakeholders, trade-offs, win{\textendash}win}, issn = {978-3-319-46709-2}, doi = {10.1007/978-3-319-46709-2_14}, url = {files/bibliography/17-008.pdf}, author = {O. E. Sala and Laura Yahdjian and Kris Havstad and M. Aguiar} } @article {JRN54776, title = {Rangelands: Where anthromes meet their limits}, journal = {Land}, volume = {6}, year = {2017}, month = {05/2017}, chapter = {31}, abstract = {

Defining rangelands as anthromes enabled Ellis and Ramankutty (2008) to conclude that more than three-quarters of Earth{\textquoteright}s land is anthropogenic; without rangelands, this figure would have been less than half. They classified all lands grazed by domestic livestock as rangelands, provided that human population densities were low; similar areas without livestock were excluded and classified instead as {\textquoteleft}wildlands{\textquoteright}. This paper examines the empirical basis and conceptual assumptions of defining and categorizing rangelands in this fashion. \ Empirically, we conclude that a large proportion of rangelands, although used to varying degrees by domesticated livestock, are not altered significantly by this use, especially in arid, highly variable environments and in settings with long evolutionary histories of herbivory by wild animals. Even where changes have occurred, the dynamics and components of many rangelands remain structurally and functionally equivalent to those that preceded domestic livestock grazing or would be found in its absence. In much of Africa and Asia, grazing is so longstanding as to be inextricable from {\textquoteleft}natural{\textquoteright} or reference conditions for those sites. Thus, the extent of anthropogenic biomes is significantly overstated. \ Conceptually, rangelands reveal the dependence of the anthromes thesis on outdated assumptions of ecological climax and equilibrium. Coming to terms with rangelands{\textemdash}how they can be classified, understood, and managed sustainably{\textemdash}thus offers important lessons for understanding anthromes and the Anthropocene as a whole. At the root of these lessons, we argue, is not the question of human impacts on ecosystems but property relations among humans.

}, doi = {10.3390/land6020031}, url = {files/bibliography/17-009.pdf}, author = {N. F. Sayre and Diana K. Davis and Brandon T Bestelmeyer and Jebediah C. Williamson} } @article {JRN54781, title = {Rainfall variability and fine-scale life history tradeoffs help drive niche partitioning in a desert annual plant community}, journal = {Ecology Letters}, year = {2017}, pages = {11 pages}, abstract = {

Tradeoffs have long been an essential part of the canon explaining the maintenance of species diversity. Despite the intuitive appeal of the idea that no species can be a master of all trades, there has been a scarcity of linked demographic and physiological evidence to support the role of resource use tradeoffs in natural systems. Using five species of Chihuahuan desert summer annual plants, I show that demographic tradeoffs driven by short-term soil moisture variation act as a mechanism to allow multiple species to partition a limiting resource. Specifically, by achieving highest fitness in either rainfall pulse or interpulse periods, variability reduces fitness differences through time that could promote coexistence on a limiting resource. Differences in fitness are explained in part by the response of photosynthesis to changing soil moisture. My results suggest that increasing weather variability, as predicted under climate change, could increase the opportunity for coexistence in this community.

}, keywords = {annual plants, comparative demography, comparative ecophysiology, intraannual variability, LTER-I Transect, niche partitioning, rainfall variablility, resource pulses, resource variability, species coexistence, tradeoffs}, doi = {10.1111/ele.12818}, url = {files/bibliography/JRN54781.pdf}, author = {Shriver, Robert K.} } @article {JRN54663, title = {The role of data and inference in the development and application of ecological site concepts and state-and-transition models}, journal = {Rangelands}, volume = {38:322-328}, year = {2016}, month = {12/2016}, abstract = {
Information embodied in ecological site descriptions and their state-and-transition models is crucial to effective land management, and as such is needed now. There is not time (or money) to employ a traditional research-based approach (i.e., inductive/deductive, hypothesis driven inference) to addressing the unknowns in developing and documenting ecological site concepts. We propose that the development of ecological site products is a dynamic task of defining concepts and processes that best explain the available data (i.e., abductive reasoning), and as such a more iterative approach to their development is needed than is currently used. Under the proposed approach, ecological site concepts are never viewed as final, but only the best representation that is supported by available knowledge and data. The natural result of this way of thinking is that products like ESDs and STMs should continually be tested and improved as new data become available.
}, doi = {10.1016/j.rala.2016.10.009}, url = {files/bibliography/16-037.pdf}, author = {Jason W. Karl and Curtis Talbot} } @inbook {JRN54563, title = {Range Ecosystems}, booktitle = {Ecosystems of California}, year = {2016}, pages = {835-864}, publisher = {University of California Press}, organization = {University of California Press}, address = {Berkeley, CA}, abstract = {

After more than two hundred years, livestock grazing remains California{\textquoteright}s most extensive land use. The {\textquoteleft}Range Ecosystems{\textquoteright} chapter in the {\textquoteleft}Ecosystems of California{\textquoteright} sourcebook provides an integrated picture of the biophysical, social, and economic aspects of lands grazed by livestock in the state. Grazing management differs considerably among the Mediterranean, desert, and montane biogeographical regions of the state. Contemporary models predicting range community responses to grazing emphasize site-specific\ nonequilibrium dynamics and integrated management goals, which include maintaining biodiversity, controlling invasive plants, managing fuels, and protecting soil, water, and air quality. Because forage resources have become limited statewide, management of public range must now consider impacts on private range. Partnerships between ranchers and rangeland landowners are essential to conserving the extensive landscapes cherished in California.

}, url = {http://www.ucpress.edu/book.php?isbn=9780520278806}, author = {S. Spiegal and Lynn Huntsinger and Hopkinson, Peter and James Bartolome} } @article {JRN54569, title = {Rapid genetic restoration of a keystone species exhibiting delayed demographic response}, journal = {Molecular Ecology}, volume = {24}, year = {2015}, month = {12/2015}, pages = {6120-6133}, chapter = {6120}, abstract = {

Genetic founder effects are often expected when animals colonize restored habitat in fragmented landscapes, but empirical data on genetic responses to restoration are limited. We examined the genetic response of banner-tailed kangaroo rats (Dipodomys spectabilis) to landscape-scale grassland restoration in the Chihuahuan Desert of New Mexico, USA. Dipodomys spectabilis is a grassland specialist and keystone species. At sites treated with herbicide to remove shrubs, colonization by D. spectabilis is slow and populations persist at low density for =10 years (=6 generations). Persistence at low density and low gene flow may cause strong founder effects. We compared genetic structure of D. spectabilis populations between treated sites and remnant grasslands, and we examined how the genetic response to restoration depended on treatment age, area, and connectivity to source populations. Allelic richness and heterozygosity were similar between treated sites and remnant grasslands. Allelic richness at treated sites was greatest early in the restoration trajectory, and genetic divergence did not differ between recently colonized and established populations. These results indicated that founder effects during colonization of treated sites were weak or absent. Moreover, our results suggested founder effects were not mitigated by treatment area or connectivity. Dispersal is negatively densitydependent in D. spectabilis, and we hypothesize that high gene flow may occur early in the restoration trajectory when density is low. Our study shows genetic diversity can be recovered more rapidly than demographic components of populations after habitat restoration and that founder effects are not inevitable for animals colonizing restored habitat in fragmented landscapes.

}, keywords = {conservation genetics, density dependence, Dipodomys spectabilis, dispersal, ecological restoration, founder effects}, doi = {10.1111/mec.13469}, url = {/files/bibliography/15-023.pdf}, author = {Brad Cosentino and Robert L. Schooley and Brandon T Bestelmeyer and McCarthy, A. and Sierzega, Kevin} } @inbook {JRN54652, title = {A risk-based strategy for climate change adaptation in dryland systems based on an understanding of potential production, soil resistance and resilience, and social stability}, booktitle = {Sustainable intensification to Advance Food Security and Enhance Climate Resilience in Africa}, volume = {Springer. pp. 407-424}, year = {2015}, publisher = {Springer International}, organization = {Springer International}, abstract = {
Climate change is expected to increase the intensity and temporal variability of storm events in many areas while reducing their frequency, resulting in increased runoff, and drought frequency and severity. Soil degradation can exacerbate these impacts by reducing both infiltration and plant-available water holding capacity. Therefore, an understanding of soil resistance and resilience to degradation is necessary to target climate change adaptation investments where they will have the largest impact. This paper (1) reviews key concepts necessary to understand the dynamic relationships between climate change adaptation, soil resistance and resilience, and social stability, and (2) provides a strategy for maximizing return on climate change adaptation investments in drylands based on an understanding of soil and ecosystem resilience. The strategy includes seven steps, which are completed for each landscape unit in the context of the surrounding landscape: (1) Determine current potential productivity based on soils, topography, and existing climate conditions. (2) Determine future potential productivity based on soil, topography, and climate change scenarios. (3) Rank landscape units based on predicted change in potential productivity. (4) Determine risk of land use change. (5) Determine degradation risk with and without land use change. (6) Rank each landscape unit based on degradation risk with and without land use change. (7) Determine priorities for climate change and soil conservation investments. The strategy described here can be applied on multiple scales to address a wide variety of objectives. We conclude by suggesting that climate change adaptation resources allocation decisions include consideration of soil resistance and resilience.
}, doi = {10.1007/978-3-319-09360-4_22}, author = {Jeffrey E. Herrick and Beh, Adam} } @article {JRN54224, title = {Responses of a desert nematode community to changes in water availability}, journal = {Ecosystems}, volume = {6}, year = {2015}, chapter = {Article 44}, abstract = {

The most recent climate models unequivocally predict a strong drying trend for the southwestern USA within the next century. Soil nematodes are a highly important component of desert ecosystem functioning, but rely on water films formovement. However, it is currently poorly understood how different trophic groups of nematodes respond to chronic presses as well as short-lived pulses of altered water availability, especially in arid systems where such changes are expected to have the greatest impact. The aim of this study was to assess the effects of both instantaneous and long-term variation in water availability on desert soil nematode trophic groups.We hypothesized that nematode abundance would respond positively to both short- and long-term increases in moisture. Based on the ecology of the different trophic groups we further made predictions about their relative rates of response. We increased or decreased precipitation from ambient levels in the Chihuahuan Desert for four consecutive years and sampled soil nematodes after two, three and four years. We tested the effects of altered precipitation treatments through time as well as gravimetric soil moisture at the time of sampling on the abundance of the different nematode trophic groups. In contrast to our hypotheses, the abundances of most nematode trophic groups were unaffected by the amount of precipitation, even after four years of altered precipitation. Plant-parasitic nematodes from low moisture soils were the only group that reacted positively to increased precipitation from the third year onwards. Trophic groups responded differently to soil moisture, with bacterivores decreasing with increasing moisture and omnivores showing a positive relationship that diminished over time. We show that in general, these desert nematodes were not limited by precipitation, and were highly resilient to decreases therein. However, when also considering the effects of soil moisture, some more complex patterns and differences among trophic groups emerged.We discuss potential mechanisms explaining these observations and contrast our findings with those from other ecosystems around the world. We conclude that deserts harbor nematode communities that seem more resilient to altered water availability than other ecosystems.

}, keywords = {drought, nematodes, precipitation, resilience, soil ecology, soil moisture, trophic groups, water availability}, doi = {10.1890/ES14-00319.1}, url = {files/bibliography/JRN00643.pdf}, author = {Vandegehuchte, Martin L. and Sylvain, Zachary A. and Lara Reichmann and Cecilia M. de Tomasel and Nielsen, Uffe N. and D.H. Wall and O. E. Sala} } @article {JRN54142, title = {Rangeland ecosystem services: shifting focus from supply to reconciling supply and demand}, journal = {Frontiers in Ecology and the Environment}, volume = {13}, year = {2015}, month = {02/2015}, pages = {44-51}, chapter = {44}, abstract = {

Ecosystem services have been extensively studied in recent decades. Most of the thousands of scholarly papers published on the subject have focused on describing the production, spatial extent, and valuation of such services. Human reliance on ecosystem services is a function of ecosystems{\textquoteright} capacity to supply and societal demand for these benefits. However, considerably more attention has been devoted to the supply side than to the demand for them. Sustainable land management depends on reconciling supply of and demand for ecosystem services among different stakeholders. The emphasis is now shifting from the supply of ecosystem services to attaining a balance between supply and demand. Here, we illustrate the demand for rangeland ecosystem services, describe current changes in societal demand, and present a specific provisioning service to exemplify the dynamic nature of reconciling ecosystem-service supply and demand.

}, keywords = {ecosystem services, land use decisions, rangelands, societal demand, supply and demand}, doi = {10.1890/140156}, url = {/files/bibliography/15-006.pdf}, author = {Laura Yahdjian and O. E. Sala and Kris Havstad} } @proceedings {JRN54046, title = {Retrieving land surface aerodynamic properties using MODIS albedo }, year = {2014}, month = {07/2014}, pages = {p. 8}, publisher = {International Society of Aeolian Research (ISAR)}, address = {Lanzhou, China}, abstract = {

Wind erosion and dust emission models are essential to estimate the lateral and vertical fluxes of carbon and nutrients between terrestrial and marine ecosystems and reduce uncertainty about dust radiative forcing of climate models. \ Wind erosion models approximate the turbulent transfer of momentum by surface roughness elements using roughness density (lateral cover or the frontal area index; Lc). \ Instead of using the aeordynamic roughness length (z0) Raupach et al. (1993) demonstrated using Marshall\’s (1971) wind tunnel data how the threshold friction velocity ratio\  Rt could be estimated as Rt(Lc). However,\  estimation of Lc over large areas (e.g., continents) is difficult and often approximated using classifications of cover (bare surfaces and vegetation type).\ \  When rough surfaces are exposed to the wind, wakes or areas of flow separation are created downwind of obstacles. These sheltered areas reduce the area of exposed substrate and protect the erodible surface \ and some of the roughness elements from the wind (depending on their size and spacing). These turbulent wakes have been conceptualised using ssheltered areas (Raupach, 1992) and shown to be proportional to shadow (Chappell et al., 2010). We made virtual reconstructions of Marshall\’s (1971) wind tunnel surfaces and applied a ray-tracer to approximate their directional (at-nadir) hemispherical \‘black-sky\’ albedo (\ωdiff(\θ, \λ)) as a function of waveband (\λ) and solar zenith angle (\θ) and their diffuse \ bi-hemispherical \‘white-sky\’ albedo \ωdiff(\θ). We normalised the albedo (\ωn=dir(\θ) / \ωdiff) such that it would not depend on (or reduce the influence of) the solar spectrum and estimated Rt(\ωn) and the friction velocity U*(\ωn) both without the use of Lc or z0. The Moderate Resolution Imaging Spectroradiometer (MODIS) includes a bi-directional reflectance model of surface roughness which provides a direct beam (local solar noon) \ωMdir and a diffuse \ωMdiff products. Normalising these products (\ωMn = \ωMdir / \ωMdiff) was equivalent to the ray-traced estimates and enabled a global estimate\  of Rt(\ωMn) and U*(\ωMn) every 500 m and every 16 days consistently using a single holistic framework of albedo. This approach also unifies the erosivity and erodibility components of wind erosion and dust emission models. We illustrate the information content of these new estimates using several spatial and temporal scales at various locations around Australia prone to wind erosion and dust emission.

}, author = {A. Chappell and Guerschman, J.P. and John Leys and Handcock, R. and Dean Thomas and G. Mata and Harry Butler and Nicholas Webb} } @article {JRN54116, title = {Restoration practices have positive effects on breeding bird species of concern in the Chihuahuan Desert}, year = {2014}, abstract = {

Woody plant encroachment into grasslands is a global concern. Efforts to restore grasslands often assume that removal of woody plants benefits biodiversity but assumptions are rarely tested. In the Chihuahan Desert of the southwestern USA, we tested whether abundances of grassland specialist bird species would be greater in plant communities resulting from treatment with herbicides to remove encroaching shrubs compared with untreated shrub-dominated areas that represented pre-treatment conditions. In 2010, we surveyed breeding birds and vegetation at 16 treated-untreated pairs. In 2011, we expanded the survey effort to 21 treated-untreated pairs, seven unpaired treatment areas, and five grassland reference areas. Vegetation in treatment areas had higher perennial grass foliar and basal cover and lower shrub foliar cover compared to untreated areas. Several regionally declining grassland specialists exhibited higher occurrence and relative abundance in treated areas. A shrubland specialist, however, was associated with untreated areas and may be negatively impacted by shrub removal. Bird community composition differed between treated and untreated areas in both years. Our results indicate that shrub removal can have positive effects on grassland specialist bird species, but that a mosaic of treated and untreated areas might be most beneficial for regional biodiversity.

}, keywords = {avian community analysis, grassland restoration, Peucaea cassinii, Polioptila melanura, rangeland management, shrub encroachment}, doi = {10.1111/rec.12081}, url = {/files/bibliography/14-023.pdf}, author = {John M. Coffman and Brandon T Bestelmeyer and J.F. Kelly and Wright, Timothy F. and Robert L. Schooley} } @article {JRN53987, title = {Resilience in ecology: abstraction, distraction, or where the action is?}, journal = {Biological Conservation}, volume = {177}, year = {2014}, month = {09/2014}, pages = {43-51}, chapter = {43}, abstract = {

Increasingly, the success of management interventions aimed at biodiversity conservation are viewed as being dependent on the {\textquoteright}resilience{\textquoteright} of the system. Although the term {\textquoteright}resilience{\textquoteright} is increasingly used by policy makers and environmental managers, the concept of {\textquoteright}resilience{\textquoteright} remains vague, varied and difficult to quantify. Here we clarify what this concept means from an ecological perspective, how it can be measured, and used to predict and manage for resilience. We argue that thresholds of disturbance are central to measuring resilience. Thresholds are important because they offer a means to quantify how much disturbance an ecosystem can absorb before switching to another state, and so indicate whether intervention might be necessary to promote the return of the predisturbance state. We distinguish between helpful and unhelpful resilience. Data to determine thresholds are not always available and so we consider the potential for indices of functional diversity to act as proxy measures of resilience. We also consider the contributions of connectivity and scale to resilience and how to incorporate these factors into management. We argue that linking thresholds to functional diversity indices may improve our ability to predict the resilience of ecosystems to future, potentially novel, disturbances according to their spatial and temporal scales of influence. Throughout, we provide guidance for the application of the resilience concept to ecosystem management. In doing so, we confirm its usefulness for improving biodiversity conservation in our rapidly changing world.

}, keywords = {Biodiversity conservation, ecological resilience, environmental policy, recovery, restoration goals, threshold}, doi = {10.1016/j.biocon.2014.06.008}, url = {/files/bibliography/14-024.pdf}, author = {Standish, Rachel and Richard J. Hobbs and Mayfield, Margie and Brandon T Bestelmeyer and Katharine N. Suding and Battaglia, Loretta and Eviner, Valerie and Hawkes, Christine and Temperton, Vicky and Harris, James and Funk, Jennifer and Peter A. Thomas} } @proceedings {JRN54041, title = {Roughness configuration matters for aeolian sediment flux}, year = {2014}, month = {07/2014}, pages = {p. 12}, publisher = {International Society of Aeolian Research (ISAR)}, address = {Lanzhou, China}, abstract = {

The parameterisation of surface roughness effects on aeolian sediment transport is a key source of uncertainty in wind erosion models. Roughness effects are typically represented by bulk drag-partitioning schemes that scale the threshold friction velocity (u*t) for soil entrainment by the ratio of shear stress on roughness elements to that on the vegetated land surface. However, the approach does not explicitly account for the effects of roughness configuration, which may be important for sediment flux. In this study we investigate (1) the significance of roughness configuration for aeolian sediment transport, (2) the ability of drag partitioning approaches to represent roughness configuration effects, and (3) the implications of our findings for model applications. We use wind tunnel measurements of surface shear stress distributions to calculate sediment flux for a suite of roughness configurations, roughness densities and wind velocities. Our results show that roughness configuration has a significant effect on sediment flux, influencing estimates by more than one order-of-magnitude. Measured and modelled drag partitioning approaches overestimate the predicted flux by two to three orders-of-magnitude. The drag partition is sensitive to roughness configuration, but current models cannot effectively represent this sensitivity. The effectiveness of drag partitioning approaches is also affected by estimates of the aerodynamic roughness height (z0) used to calculate wind shear velocity (u*). Unless the roughness height is consistent with the drag partition and u*t, resulting fluxes can show physically implausible patterns. These results should make us question current assessments of the magnitude of vegetated dryland dust emissions. Representing roughness effects on surface shear stress distributions will reduce uncertainty in quantifying wind erosion, enabling better assessment of its impacts and management solutions.

}, author = {Nicholas Webb and Gregory S. Okin and Brown, Shannon} } @conference {JRN53999, title = {The role of carbon dust emission as a global source of atmospheric CO2}, booktitle = {Soil Carbon Sequestration for Climate, Food Security and Ecosystem Services International Conference}, year = {2013}, month = {05/2013}, address = {Reykjavid, Iceland}, abstract = {

Soil erosion redistributes soil organic carbon (SOC) within terrestrial ecosystems, to the atmosphere and oceans. Dust export is an essential component of the carbon (C) and carbon dioxide (CO2) budget, because wind erosion contributes to the C cycle by selectively removing SOC from vast areas and transports C dust quickly offshore; augmenting the net loss of carbon from terrestrial systems. However, the contribution of wind erosion to rates of carbon release and sequestration is poorly understood. Here we show that SOC dust emission is omitted from national carbon accounting, is an under-estimated source of CO2 and a largely unaccounted-for, likely accelerant of SOC decomposition. We developed a first approximation to SOC enrichment for a dust emission model and quantified SOC dust emission for Australia (5.83 Tg CO2-e y-1) and Australian agricultural soils (0.4 Tg CO2-e y-1). These amount to under-estimates for CO2 emissions of ~10\% from combined C pools in Australia (yr=2000), ~5\% from Australian Rangelands and ~3\% of Australian Agricultural Soils by Kyoto Accounting. Northern hemisphere countries with greater dust emission than Australia are also likely to have much larger SOC dust emission. Therefore, omission of SOC dust emission also likely represents a considerable underestimate from those nation\’s carbon accounts.

}, author = {A. Chappell and Nicholas Webb and Harry Butler and Craig Strong and Grant McTainish and Lleys, John and Raphael A. Viscarr Rossel} } @article {49845, title = {Response of lizard community structure to desert grassland restoration mediated by a keystone rodent}, journal = {Biodiversity and Conservation Journal}, volume = {22}, year = {2013}, month = {02/2013}, pages = {921-935}, chapter = {921}, abstract = {

Many grasslands in the Chihuahuan Desert have transformed to shrublands dominated by creosotebush (Larrea tridentata). Grassland restoration efforts have been directed at controlling creosotebush by applying herbicide over large spatial scales. However, we have a limited understanding of how landscape-scale restoration affects biodiversity. We examined whether restoration treatments in southern New Mexico, USA have influenced the community structure of lizards, which are sensitive to shrub encroachment. We compared lizard community structure on 21 sites treated with herbicide from 7-29 years ago with paired references matched by geomorphology, soils, and elevation. To examine mechanisms underlying responses to restoration, we tested whether the abundance of a grassland specialist, Aspidoscelis uniparens, depended on time since treatment, treatment area and isolation, and local habitat quality. Because lizards use rodent burrows as habitat, we tested whether community structure and A. uniparens abundance depended on the abundance of the keystone rodent, Dipodomys spectabilis. Treatments had reduced shrub cover and increased grass cover compared to references. Lizard community composition differed strongly between plots, with four species responding to treatments. Divergence in community composition between treatment-reference pairs was greatest for old treatments (=22 years), and community composition was influenced by D. spectabilis. In particular, the abundance of A. uniparens was greatest on old treatments with a high density of D. spectabilis. Overall, our results demonstrate lizard community structure responds to grassland restoration efforts, and keystone species can shape restoration responses. Reestablishment of keystone species may be a critical constraint on the recovery of animal biodiversity after habitat restoration.

}, keywords = {Aspidoscelis spp., desertification, Dipodomys spectabilis, grassland restoration, keystone species, shrub encroachment}, doi = {10.1007/s10531-013-0459-7}, url = {/files/bibliography/13-021.pdf}, author = {Brad Cosentino and Robert L. Schooley and Brandon T Bestelmeyer and John M. Coffman} } @proceedings {JRN53998, title = {Relationship between one-seed juniper terpene concentration and herbivory by small ruminants}, volume = {91}, year = {2013}, month = {07/2013}, pages = {553}, publisher = {Journal of Animal Science}, address = {Indianapolis, IN}, abstract = {

Plant secondary metabolite affect the amount of use by herbivores for serveral woody species.\  We examined the relationship between terpenoid concentrations and Juniperus monosperma herbivory by small ruminants.\  The study was part of a larger effort in which goats (n = 10) or mixed species (5 goats and 4 sheep) were allotted to 16 plots (20 \× 30 m) containing one-seed juniper for 6 d during 2 seasons at 2 stocking rates. Juniper leaves were sampled from 311 saplings on the same day they were browsed. Saplings were categorized by size (small [\<0.5 m], medium [0.5-1.0 m] or tall [\>1.0 m]) and browsing intensity (low [\<33\%], moderate [33-66\%] or heavy [\>66\%] herbivory). Juniper bark was also collected from 12 saplings during spring. Leaves and bark were analyzed for terpenoids with gas chromatography-mass spectrometry. Terpene data were pooled across species and stocking rate and ANOVA was conducted for season, sapling size, and herbivory level. The volatile profile of one-seed juniper leaves and bark consisted of 65 and 55 compounds, respectively. Total estimated terpenoid concentrations in leaves and bark were 18.3 \± 0.3 and 8.9 \± 0.8 mg/g, respectively, and the dominant terpene in both tissues was \α-pinene (11.1 \± 0.2 and 7.6 \± 0.7 mg/g, respectively). Total terpenoid concentration was greater (P \< 0.001) in spring than summer (20.6 \± 0.5 vs. 16.7 \± 0.3 mg/g, respectively) and lower (P \< 0.001) in small saplings than medium or tall saplings (16.5 \± 0.6 vs. 19.8 \± 0.4 and 19.5 \± 0.4 mg/g, respectively). Total concentration also differed (P \< 0.001) among all 3 browsing categories (16.1 \± 0.4, 18.7 \± 0.5, and 21.2 \± 0.6 mg/g for heavy, moderate, and light herbivory, respectively). Approximately 42\% of the variation in browsing intensity could be explained (P \< 0.001) by 12 compounds ([E]-\β-farnesene, cis-sabinene hydrate, bornyl acetate, \γ-eudesmol, germacrene A, \γ-cadinene, \α-pinene, [Z]-\β-ocimene, terpin-4-ol, cispiperitol, cis-p-menth-2-en-1-ol, and camphene hydrate). Our results indicate that the terpene profile of one-seed juniper is related to sapling size, season, and degree of use by sheep and goats.

}, keywords = {goat, sheep, terpene}, author = {Richard E. Estell and S. A. Utsumi and Andr{\'e}s F. Cibils and D.M. Anderson} } @inbook {JRN52674, title = {Recommendations for data accessibility}, year = {2013}, pages = {216-225}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {16}, address = {Springfield, Virginia}, abstract = {

The EcoTrends project has generated hundreds of standardized, documented datasets from many sites and scientific fields.\  During the process of generating data comparable between many sites and across several organizational networks, novel solutions to technical, organizational, and communication challenges have been created.\  This chapter presents ten recommendations for site-level information management and for future synthesis projects.\  The recommendations are related to three broad categories: (1) data management and products, (2) project design, and (3) information environments to support synthesis projects. For each recommendation, the chapter provides specific examples of the challenges that EcoTrends faced, the lessons learned, and then explains the recommendation that may help address the challenge in future projects.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-16.pdf}, author = {C. Laney and Baker, K. S. and Debra C. Peters and Ken Ramsey} } @article {49856, title = {Regional signatures of plant response to drought and elevated temperature across a desert ecosystem}, journal = {Ecology}, volume = {94}, year = {2013}, month = {09/2013}, pages = {2030-2041}, chapter = {2030}, abstract = {

The performance of many desert plant species in North America may decline with the warmer and drier conditions predicted by climate change models, thereby accelerating land degradation and reducing ecosystem productivity. We paired repeat measurements of plant canopy cover with climate at multiple sites across the Chihuahuan Desert over the last century to determine which plant species and functional types may be the most sensitive to climate change. We found that the dominant perennial grass, Bouteloua eriopoda, and species richness had nonlinear responses to summer precipitation, decreasing more in dry summers than increasing with wet summers. Dominant shrub species responded differently to the seasonality of precipitation and drought, but winter precipitation best explained changes in the cover of woody vegetation in upland grasslands and may contribute to woody-plant encroachment that is widespread throughout the southwestern United States and northern Mexico. Temperature explained additional variability of changes in cover of dominant and subdominant plant species. Using a novel empirically based approach we identified {\textquoteleft}{\textquoteleft}climate pivot points{\textquoteright}{\textquoteright} that were indicative of shifts from increasing to decreasing plant cover over a range of climatic conditions. Reductions in cover of annual and several perennial plant species, in addition to declines in species richness below the long-term summer precipitation mean across plant communities, indicate a decrease in the productivity for all but the most drought-tolerant perennial grasses and shrubs in the Chihuahuan Desert. Overall, our regional synthesis of long-term data provides a robust foundation for forecasting future shifts in the composition and structure of plant assemblages in the largest North American warm desert.

}, keywords = {Chihuahuan Desert, climate change, climate pivot point, desertification, forecasting plant community composition, land degradation, long-term vegetation dynamics, plant canopy cover, species richness}, doi = {10.1890/12-1586.1}, url = {/files/bibliography/13-027.pdf}, author = {Seth M. Munson and E. Muldavin and Jayne Belnap and Debra C. Peters and John P. Anderson and M. Hildegard Reiser and Gallo, Kirsten and Melgoza-Castillo, Alicia and Jeffrey E. Herrick and Christiansen, Tim A.} } @article {49866, title = {Runoff responses to long-term rainfall variability in a shrub-dominated catchment}, journal = {Journal of Arid Environments}, volume = {91}, year = {2013}, month = {01/2013}, pages = {88-94}, chapter = {88}, abstract = {In this study we investigate how rainfall has changed between two nine year periods (1977-1985 and 2003-2011), and evaluate the effects of changes in rainfall on runoff from a shrub-dominated catchment in the southwestern USA. Analysis of rainfall characteristics shows that between these two periods there is an overall increase in annual rainfall, which corresponds with a long-term increase in rainfall in this region. Analysis of the frequency-magnitude distribution of rainfall events during these two periods indicates that there has not been a significant change in the return period of daily rainfall totals, whereas there has been a significant change in the return period of runoff-generating rainfall events. Between the two periods, there has been a large increase in the return period for a runoff event of a given magnitude. Although there has been an increase in rainfall between the two periods, results show that, contrary to
what might be expected, an overall increase in rainfall has not resulted in an increase in runoff because of a change in the frequency-magnitude distribution of runoff-generating rainfall events. We anticipate that this reduction in runoff is due to a reduction in rainfall intensities between the two periods.\  \© 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jaridenv.2012.12.002}, keywords = {climate change, frequency, magnitude, rainfall, runoff response, Tromble Weir}, doi = {10.1016/j.jaridenv.2012.12.002}, url = {/files/bibliography/13-004.pdf}, author = {Turnbull, L. and A.J. Parsons and John Wainwright and John P. Anderson} } @proceedings {JRN54553, title = {Response of a keystone rodent to landscape-scale restoration of desert grasslands}, volume = {B117}, year = {2012}, month = {08/2012}, publisher = {Ecological Society of America}, address = {Portland, Oregon}, abstract = {Over the last century, many grasslands in the Chihuahuan Desert have converted to shrublands dominated by creosotebush (Larrea tridentata). The loss and spatial isolation of perennial grasslands has led to declines of grassland-dependent wildlife species. Grassland restoration efforts have been dominated by the application of herbicide to control creosotebush over large spatial scales. However, we have a limited understanding of how landscape-scale restoration has affected wildlife species. We examined whether restoration treatments in southern New Mexico have increased the abundance of the banner-tailed kangaroo rat (Dipodomys spectabilis), a keystone rodent that forages on perennial grasses. We selected 21 sites that were treated with herbicide from 7-29 years ago, and we compared the abundance of D. spectabilis on treated areas with paired reference sites that were dominated by creosotebush. To examine potential constraints on restoration success, we also tested whether the response of D. spectabilis depended on time since treatment, treatment area, and broader landscape connectivity. The abundance of D. spectabilis was greater on sites treated with herbicide than on paired references. However, the response of D. spectabilis depended on time since treatment and spatial connectivity. Abundance was related positively to treatment age, suggesting a lagged response of D. spectabilis to restoration. Abundance also increased with connectivity to other restoration sites, indicating that restoration success can depend on landscape context. Abundance was particularly high at sites that were near old treatments. The area of treatments did not have a strong effect on abundance. Dipodomys spectabilis greatly affects ecosystem functioning, and it improves habitat for other wildlife species by constructing large mounds that provide cover. Overall, our results suggest that recolonization by D. spectabilis at restoration sites may depend on the age and spatial configuration of treated areas.}, author = {Brad Cosentino and Robert L. Schooley and Brandon T Bestelmeyer and John M. Coffman} } @article {49879, title = {Rangeland and pasture monitoring: an approach to interpretation of high-resolution imagery focused on observer calibration for repeatability}, journal = {Environmental Monitoring and Assessment}, volume = {184}, year = {2012}, month = {07/23/2011}, pages = {3789-3804}, chapter = {3789}, abstract = {

Collection of standardized assessment and monitoring data is critically important for supporting policy and management at local to continental scales. Remote sensing techniques, including image interpretation, have shown promise for collecting plant community composition and ground cover data efficiently. More work needs to be done, however, evaluating whether these techniques are sufficiently feasible, cost-effective, and repeatable to be applied in large programs. The goal of this study was to design and test an image-interpretation approach for collecting plant community composition and ground cover data appropriate for local and continental-scale assessment and monitoring of grassland, shrubland, savanna, and pasture ecosystems. We developed a geographic information system image-interpretation tool that uses points classified by experts to calibrate observers, including point-by-point training and quantitative quality control limits. To test this approach, field data and high-resolution imagery (\~{}3 cm ground sampling distance) were collected concurrently at 54 plots located around the USA. Seven observers with little prior experience used the system to classify 300 points in each plot into ten cover types (grass, shrub, soil, etc.). Good agreement among observers was achieved, with little detectable bias and low variability among observers (coefficient of variation in most plots \<0.5). There was a predictable relationship between field and image-interpreter data (R (2) \> 0.9), suggesting regression-based adjustments can be used to relate image and field data. This approach could extend the utility of expensive-to-collect field data by allowing it to serve as a validation data source for data collected via image interpretation.

}, keywords = {aerial photography, assessment and monitoring, image interpretation, large-scale, remote sensing, repeatability}, doi = {10.1007/s10661-011-2224-2}, url = {/files/bibliography/12-005.pdf}, author = {Danielle Duni and Jason W. Karl and Scott T. Schrader and Noemi Baquera and Jeffrey E. Herrick} } @article {49880, title = {Reintroduced prairie dog colonies change arthropod communities and enhance burrowing owl foraging resoruces}, journal = {Immediate Science Ecology}, volume = {l}, year = {2012}, month = {12/2012}, pages = {12-23}, chapter = {12}, abstract = {

In the western United States, human activities have decreased black-tailed prairie dog (Cynomys ludovic-ianus) populations to \<10\% of their historic extent. These animals are ecosystem engineers that radically alter soil physical and chemical characteristics and plant communities on their colonies. We tested the hypothesis that prairie dogs have an impact on higher levels of grassland ecology by measuring the differ-ences in arthropod community structure and burrowing owl foraging on those arthropods, between reintro-duced colonies and adjacent grassland in southern New Mexico, USA. Arthropod communities differed be-tween colonies and grassland in both number of taxa and abundance. Burrowing owls foraged more on col-onies, and caught more prey on colonies compared to grasslands. Pursuit times of burrowing owls in grass-land were longer than pursuits on colonies. Burrowing owls nesting on the edge of colonies foraged extens-ively on colonies, and edge and center-nesting owls delivered similar proportions of prey captured on colonies to their nests. This study suggests that prairie dogs play a vital role in structuring arthropod commun-ities and provide foraging resources for other grassland species.

}, url = {/files/bibliography/12-044.pdf}, author = {B.D. Duval and Walter G. Whitford} } @article {49885, title = {Revolutionary land use change in the 21st century: Is (rangeland) science relevant?}, journal = {Rangeland Ecology and Management}, volume = {65}, year = {2012}, month = {11/2012}, pages = {590-598}, chapter = {590}, abstract = {

Rapidly increasing demand for food, fiber and fuel together with new technologies and the mobility of global capital are driving revolutionary changes in land use throughout the world. Efforts to increase land productivity include conversion of millions of hectares of rangelands to crop production, including many marginal lands with low resistance and resilience to degradation. Sustaining the productivity of these lands requires careful land use planning and innovative management systems. Historically, this responsibility has been left to agronomists and others with expertise in crop production. In this paper, we argue that the revolutionary land use changes necessary to support national and global food security potentially make rangeland science more relevant now than ever. Maintaining and increasing relevance will require a revolutionary change in range science from a discipline that focuses on a particular land use or land cover to one that addresses the challenge of managing all lands that, at one time, were considered to be marginal for crop production. We propose four strategies to increase the relevance of rangeland science to global land management: (1) expand our awareness and understanding of local to global economic, social, and technological trends in order to anticipate and identify drivers and\  patterns of conversion, (2) emphasize empirical studies and modeling that anticipate the biophysical (ecosystem services) and societal consequences of large-scale changes in land cover and use, (3) significantly increase communication and collaboration with the disciplines and sectors of society currently responsible for managing the new land uses, and (4) develop and adopt a dynamic and flexible resilience-based land classification system and data-supported conceptual models (e.g., State and Transition models) that represent (a) all lands, irrespective of use and (b) the consequences of land conversion to various uses, instead of changes in state or condition that are focused on a single land use.

}, keywords = {degradation, economics, food security, resilience, soil depth, sustainable land management}, doi = {10.2111/REM-D-11-00186.1}, url = {/files/bibliography/12-030.pdf}, author = {Jeffrey E. Herrick and Joel R. Brown and Brandon T Bestelmeyer and S. Andrews and Baldi, G. and J. Davis and Danielle Duni and Kris Havstad and Jason W. Karl and Karlen, D.L. and Debra C. Peters and Quinton, J. N. and C. Riginos and P. L. Shaver and Diego Steinaker and Twomlow, S.} } @article {49895, title = {Relationship between plant lipid bodies and fungal endophytes}, journal = {Terra Latinoamerica}, volume = {30}, year = {2012}, month = {03/01/2012}, pages = {39-45}, chapter = {39}, abstract = {Lipid bodies are universal components of plant cells and provide a mobilized carbon source for essential biological processes.\  Plant oils harvested for food and fuel often reside in these lipid bodies.\  Plants also host diverse populations of endophytic fungi, which easily escape microscopic detection.\  This study reviews data from previous surveys of endophyte distribution in native plants to specifically examine the physical association between endophytic fungi and plant lipid bodies.\  Plant tissues stained with trypan blue and sudan IV prior to differential interference contrast microscopy revealed lipid bodies tightly associated with fungal hyphae and with trypan blue stained fungal networks.\  The abundance of endophyte-associated lipids in healthy plant tissues suggests endophyte involvement in carbon (oil) metabolism and transport.\  More research, particularly at the molecular level, is merited to assess the significance of this plant feature which is conserved in grasses and shrubs.\  Exploring the interfaces where plant cells and endophyte cells exchange organic carbon using modern imaging, molecular and genomic analysis could transform current understanding of plant carbon metabolism.}, keywords = {arid zones, biofuel, endophyte, fungi, stress resistance}, url = {/files/bibliography/12-011.pdf}, author = {P. Osuna-Avila and J.R. Barrow and M.E. Lucero and Aaltonen, R.E.} } @article {49903, title = {The {\textquoteright}range problem{\textquoteright} after a century of rangeland science: New research themes for altered landscapes}, journal = {Rangeland Ecology and Management}, volume = {65}, year = {2012}, month = {11/2012}, pages = {545-552}, chapter = {545}, abstract = {

The rangeland science profession in the United States has its roots in the widespread overgrazing and concurrent severe droughts of the late 19th Century. These drivers contributed to rangeland resource degradation especially in the American Southwest-what E. O. Wooton (1908) called "The Range Problem." Although logical for the time, the scientific activities and resulting policies that arose out of this catastrophe were based on reductionist experimentation and productionist emphases on food and fiber. After a century of science and policy there are two additional perspectives that shape our vision for the emphases of the future. First, rangeland landscapes are extremely heterogeneous; general principles derived from scientific experimentation cannot be easily, or generally, applied without adjusting to the distinct societal and ecological characteristics of a location. Second, rangeland management occurs at spatial scales considerably larger than those that have typically been addressed in range science. Scaling up science results is not a simple, additive process. The leading features of the emerging science are (1) research at landscape scales and (2) over longer time spans, that (3) approaches conservation and management practices as treatments requiring scientific evaluation, (4) incorporates local knowledge, (5) is explicitly applied in nature, and (6) is transparent in its practice. We strongly argue for a science that supports resource management by testing hypotheses relevant to actual conservation practices and iteratively applying its findings in partnership with managers in an ongoing, adaptive fashion.

}, keywords = {applied science, ecosystem management, range science history, science-management linkages, translational science}, doi = {10.2111/REM-D-11-00113.1}, url = {/files/bibliography/12-029.pdf}, author = {N. F. Sayre and William deBuys and Brandon T Bestelmeyer and Kris Havstad} } @article {49909, title = {Response of dominant grass and shrub species to water manipulation: An ecophysiological basis for shrub invasion in a Chihuahuan Desert grassland}, journal = {Oecologia}, volume = {169}, year = {2012}, month = {01/15/2012}, pages = {373-383}, chapter = {373}, abstract = {Increases in woody vegetation and declines in grasses in arid and semi-arid ecosystems have occurred globally since the 1800s, but the mechanisms driving this major land-cover change remain uncertain and controversial. Working in a shrub-encroached grassland in the northern Chihuahuan Desert where grasses and shrubs typically differ in leaf-level nitrogen allocation, photosynthetic pathway, and root distribution, we asked if differences in leaflevel ecophysiology could help explain shrub proliferation. We predicted that the relative performance of grasses and shrubs would vary with soil moisture due to the diVerent morphological and physiological characteristics of the two life-forms. In a 2-year experiment with ambient, reduced, and enhanced precipitation during the monsoon season, respectively, the encroaching C3 shrub (honey mesquite Prosopis glandulosa) consistently and substantially outperformed the historically dominant C4 grass (black grama Bouteloua eriopoda) in terms of photosynthetic rates while also maintaining a more favorable leaf water status. These differences persisted across a wide range of soil moisture conditions, across which mesquite photosynthesis was decoupled from leaf water status and moisture in the upper 50 cm of the soil proWle. Mesquite\’s ability to maintain physiologically active leaves for a greater fraction of the growing season than black grama potentially ampliWes and extends the importance of physiological differences. These physiological and phenological differences may help account for grass displacement by shrubs in drylands. Furthermore, the greater sensitivity of the grass to low soil moisture suggests that grasslands may be increasingly susceptible to shrub encroachment in the face of the predicted increases in drought intensity and frequency in the desert of the southwestern USA.}, keywords = {drought, grassland community, Jornada, photosynthesis, precipitation manipulation, shrub invasion, water manipulation, water potential, woody encroachment}, doi = {10.1007/s00442-011-2217-4}, url = {/files/bibliography/12-015.pdf}, author = {Heather L. Throop and Lara Reichmann and O. E. Sala and Steven R. Archer} } @article {49925, title = {Rotational grazing systems and livestock grazing behavior in shrub-dominated semi-arid and arid rangelands}, journal = {Rangeland Ecology and Management}, volume = {64}, year = {2011}, month = {01/2011}, pages = {1-9}, chapter = {1}, abstract = {

Rotational grazing systems (RGS) are often implemented to alleviate undesirable selective grazing by livestock. At both fine and coarse scales, livestock selectively graze individual plants, patches, communities, and landscapes. Smaller pastures, increased stocking density, and rotation allow managers to constrain livestock movement and determine season and frequency of grazing, potentially limiting selectivity and preventing repeated grazing of preferred plants. However, in arid and semi-arid rangelands, forage growth is limited primarily by precipitation rather than defoliation frequency. When soil moisture is adequate, forage is abundant and defoliation levels are typically low, and repeated, intensive defoliation of preferred plants is less likely than in more mesic areas where more consistent precipitation and soil moisture storage allows animals to establish and maintain spatial hierarchies of grazing patterns. Many southwestern rangelands contain diverse vegetation, which provides quality forage during different times of the year. These spatial and temporal patterns of forage distribution may not be amenable to manipulation with RGS. Tracking data show that livestock often alternate among locations within pasture boundaries and can opportunistically exploit areas with higher quality forage when they are available. Higher stock densities combined with higher stocking rates can increase livestock use of less preferred areas, but overall distribution patterns of intensive-rotational and extensive grazing systems are often comparable at similar stocking rates and distances from water. Management that ensures that grazing of riparian areas does not occur during the critical late summer period may be more beneficial than RGS that periodically defers livestock use throughout the grazing season. In arid and semi-arid shrublands, timely adjustments to animal numbers and practices that improve grazing distribution at regional and landscape scales are more likely to be effective in maintaining or improving rangeland health than fencing and RGS.

}, keywords = {foraging strategies, grazing management, grazing systems, livestock behavior, livestock distribution, stocking density}, doi = {10.2111/REM-D-09-00184.1}, url = {/files/bibliography/11-042.pdf}, author = {C. Donovan Bailey and Joel R. Brown} } @article {49950, title = {Rangeland assessment and monitoring methods guide}, journal = {Rangelands}, volume = {33}, year = {2011}, month = {08/2011}, pages = {48-54}, chapter = {48}, abstract = {A common concern expressed by land managers and biologists is that they do not know enough about the strengths and weaknesses of different field and remote-sensing methods for rangeland assessment and monitoring. The Methods Guide is a web-based tool and resource that provides researchers and managers information necessary to make informed decisions about which field and remote-sensing method or combination of methods could be most useful and cost effective for their management needs. The Methods Guide helps users make more informed decisions about which method or combination of methods best fits their individual assessment and monitoring information needs.bib}, doi = {10.2111/1551-501x-33.4.48}, url = {/files/bibliography/11-026.pdf}, author = {Jason W. Karl and Colson, Karen and Swartz, Heather} } @article {49965, title = {Responses of wind erosion to climate-induced vegetation changes on the Colorado Plateau}, journal = {Proceedings of the National Academy of Sciences}, volume = {108}, year = {2011}, pages = {3854-3859}, abstract = {

Projected increases in aridity throughout the southwestern United States due to anthropogenic climate change will likely cause reductions in perennial vegetation cover, which leaves soil surfaces exposed to erosion. Accelerated rates of dust emission from wind erosion have large implications for ecosystems and human wellbeing, yet there is poor understanding of the sources and magnitude of dust emission in a hotter and drier climate. Here we use a two-stage approach to compare the susceptibility of grasslands and three different shrublands to wind erosion on the Colorado Plateau and demonstrate how climate can indirectly moderate the magnitude of aeolian sediment flux through different responses of dominant plants in these communities. First, using results from 20 y of vegetation monitoring, we found perennial grass cover in grasslands declined with increasing mean annual temperature in the previous year, whereas shrub cover in shrublands either showed no change or declined as temperature increased, depending on the species. Second, we used these vegetation monitoring results and measurements of soil stability as inputs into a field-validated wind erosion model and found that declines in perennial vegetation cover coupled with disturbance to biological soil crust resulted in an exponential increase in modeled aeolian sediment flux. Thus the effects of increased temperature on perennial plant cover and the correlation of declining plant cover with increased aeolian flux strongly suggest that sustained drought conditions across the southwest will accelerate the likelihood of dust production in the future on disturbed soil surfaces.

}, keywords = {arid, climate change, Colorado Plateau, horizontal flux, land use, national park, threshold shear velocity, vegetation change, wind erosion}, doi = {10.1073/pnas.1014947108}, url = {files/bibliography/JRN00582.pdf}, author = {Seth M. Munson and Jayne Belnap and Gregory S. Okin} } @conference {JRN54509, title = {Responses to climate change in hot desert ecosystems: connecting local to global scales}, booktitle = {96th Ecological Society of America Annual Meeting}, year = {2011}, month = {08/2011}, publisher = {Ecological Society of America}, organization = {Ecological Society of America}, address = {Austin, TX}, abstract = {

The consequences of connectivity in resources, propagules, and information to the interplay between drivers and responses across scales can result in ecological dynamics that are not easily predicted based on local drivers. Three major classes of connectivity events link local ecological dynamics with broader scale drivers. These events differ in initial driver characteristics (intensity, spatial extent, duration), rate of change in response through space, and the relative importance of driver characteristics versus ecological properties and land cover through time. As a result, the impacts of drivers on ecological systems can be synchronized, attenuated or amplified through time and space. Here, I examine how these three classes can interact during the course of a climatic event to result in surprising ecological responses, and a potential state change reversal in the largest desert of North America. A hurricane in 2008 resulted in unusually large amount of summer rainfall, and resulted in a broad-scale recruitment of perennial grasses in degraded shrublands. Successive years of average and below-average rainfall amplified the growth and spatial propagation of grasses via plant-soil feedbacks at the scale of individual plants. Continued interactions across scales are expected to push the system towards a new state codominated by grasses and shrubs. These complex cross-scale dynamics are not unique to this system, and suggest that effective predictions of future dynamics will require a consideration of changing drivers and landuse across scales that include both contiguous and non-adjacent locations.

}, author = {Debra C. Peters} } @article {50003, title = {Reinterpreting historical data for evidence-based shrubland management}, journal = {Natural Resources and Environmental Issues}, volume = {17}, year = {2011}, month = {01/15/2011}, pages = {1-10}, chapter = {Article 18}, abstract = {

Long-term vegetation dynamics in the Chihuahuan Desert of southern New Mexico have been intensively studied for over a century, and interpretations of the broad scale drivers of these dynamics are numerous. We now understand that interpretation of spatially heterogeneous change requires a more nuanced, contextualized, and detailed understanding of edaphic features and landscape characteristics. Recently, state and transition models (STMs) have been employed to represent landscape-specific dynamics for each ecological site within a Major Land Resource Area (MLRA). We re-examined data characterizing vegetation across the public lands of the northern Chihuahuan Desert at two points in time, the 1930s and 2005. In this study, our objectives were to (1) develop geospatial data layers of historical and current vegetation states, (2) compare vegetation states between the 1930s and 2005 where the two data layers overlap, and (3) interpret any major vegetation state changes over this ~70 year period within the context of specific ecological sites. It was our hypothesis that ecological dynamics would vary in interpretable ways among ecological sites. Three primary observations are drawn from our results: (1) the bulk of the region was relatively stable during this period, (2) approximately the same amount of area experienced increased grass dominance as experienced increased shrub dominance, and (3) dynamics are strongly influenced by the properties of specific ecological sites. Major vegetation state changes, involving either increased grass dominance or increased shrub dominance, only occurred to any extent in 11 of 18 ecological sites within this study area. More important to management, significant increases in shrubs occurred within only four ecological sites. These sites were sandy, deep sand, shallow sandy, and gravelly sand. All other ecological sites within this region were relatively stable over the ~70 year period between observations. The obvious management implication is the importance of stratifying by ecological site prior to application of shrub control treatments.

}, url = {/files/bibliography/11-040.pdf}, author = {Jebediah C. Williamson and Laura M. Burkett and Brandon T Bestelmeyer and R. K. Skaggs and Kris Havstad} } @conference {JRN54458, title = {Resilience mechanisms and recovery in a Chihuahuan Desert rangeland ecosystem}, booktitle = {95th Ecological Society of America Meeting}, year = {2010}, month = {08/2010}, address = {Pittsburga, PA}, abstract = {

Background: Desert grassland ecosystems of the Chihuahuan Desert, and other parts of the southwestern U.S., underwent significant changes from the late 1800s through the 1950s. Most often, grassland states were converted to shrubland states. Such transitions have been associated with diminished livestock production, erosion, reduced soil water retention and diminished net primary production, and biodiversity loss. Synthesizing across a number of data sources, we first describe the social and ecological mechanisms that precipitated transitions. We then describe several elements of resilience in the Chihuahuan Desert that have been discovered and their implications for ongoing management. Results/Conclusions: Evidence from the Jornada Basin LTER indicates that transitions from grassland to shrublands were triggered by a failure to reduce livestock numbers during periods of low rainfall. These events caused initial perennial grass mortality and subsequent feedbacks with soil degradation, paralleled by shrub establishment and survival. Theory and observation suggests that a threshold is crossed once sufficient grass biomass is lost and feedbacks with soil erosion and reduced water availability drive remaining grasses extinct. Recent work, however, indicates several factors that have contributed to grassland resilience in the face of these processes. First, the occurrence of transitions across the landscape was buffered by variation in soil and landscape properties that influence soil water availability such that grasses were preserved in many areas. Second, net primary productivity of eroding shrubland states is, remarkably, not lower than that of grasslands although the response of these states to rainfall differs. Third, a recent large precipitation event revealed that remnant and colonizing grasses can reverse perennial grass loss, even if temporarily, on what were thought to be irreversibly degraded soils. Finally, degradation episodes in the first half of the 20th century have radically transformed institutions and perceptions such that livestock management is more responsive to high-risk conditions. Here, as in other arid ecosystems, scientists have focused largely on the mechanisms of degradation rather than strategies to exploit resilience. Abstract $\#$ OOS 8-4

}, author = {Brandon T Bestelmeyer and Kris Havstad and Danielle Duni and Debra C. Peters} } @article {JRN52698, title = {Rapid response of a grassland ecosystem to an experimental manipulation of a keystone rodent and domestic livestock}, journal = {Ecology}, volume = {91}, year = {2010}, month = {2010}, pages = {3189-3200}, chapter = {3189}, abstract = {

Megaherbivores and small burrowing mammals commonly co-exist and play important functional roles in grassland ecosystems worldwide. The interactive effects of these two functional groups of herbivores in shaping the structure and function of grassland ecosystems are poorly understood. In North America\’s central grasslands, domestic cattle (Bos taurus) have supplanted bison (Bison bison), and now co-exist with prairie dogs (Cynomys spp.), a keystone burrowing rodent. Understanding the ecological relationships between cattle and prairie dogs and their independent and interactive effects is essential to understanding the ecology and important conservation issues affecting North American grassland ecosystems. To address these needs, we established a long-term manipulative experiment that separates the independent and interactive effects of prairie dogs and cattle using a 2 x 2 factorial design. Our study is located in the Janos-Casas Grandes region of northwestern Chihuahua, Mexico, which supports one of the largest remaining complexes of black-tailed prairie dogs (C. ludovicianus). Two years of post-treatment data show nearly 2-fold increases in prairie dog abundance on plots grazed by cattle compared to plots without cattle. This positive effect of cattle on prairie dogs resulted in synergistic impacts when they occurred together. Vegetation height was significantly lower on the plots where both species co-occurred compared to where either or both species was absent. The treatments also significantly affected abundance and composition of other grassland animal species, including grasshoppers and banner-tailed kangaroo rats. Our results demonstrate that two different functional groups of herbivorous mammals, burrowing mammals and domestic cattle, have distinctive and synergistic impacts in shaping the structure and function of grassland ecosystems.

}, keywords = {cattle, Chihuahuan Desert, ecosystem engineers, grasshoppers, grassland, grazing, herbivores, keystone species, prairie dogs, vegetation}, url = {/files/bibliography/10-038.pdf}, author = {A.D. Davidson and Ponce, Ed and David C. Lightfoot and E.L. Fredrickson and Joel R. Brown and Burzado, J. and David P. Toledo and S.L. Brantley and Sierra, R. and Lisk, R. and G. Ceballos} } @proceedings {50059, title = {Rangeland resource assessment, monitoring, and management using unmanned aerial vehicle-based remote sensing}, volume = {Art. No. 1470}, year = {2010}, month = {07/25/2010}, pages = {608-611}, address = {Honolulu, Hawaii}, abstract = {

Civilian applications of Unmanned Aerial Vehicles (UAV) have rapidly been expanding recently. Thanks to military development many civil UAVs come via the defense sector. Although numerous UAVs can perform civilian tasks, the regulations imposed by FAA in the national airspace system and military equivalent agencies in restricted airspace need to be closely considered and followed in order to make progress in civilian applications. Personnel at the Jornada Experimental Range have developed approaches to abide by FAA and military regulations. Because of this, the enormous potential of UAVs for rangeland assessment, monitoring, and management is starting to be realized.

}, doi = {10.1109/IGARSS.2010.5651659}, url = {/files/bibliography/10-029.pdf}, author = {A. Rango and Andrea S. Laliberte and Kris Havstad and Craig Winters and Caitriana Steele and Dawn M. Browning} } @inbook {50074, title = {Resilience theory in models of rangeland ecology and restoration: the evolution and application of a paradigm}, booktitle = {New Models for Ecosystem Dynamics and Restoration}, year = {2009}, month = {2009}, pages = {78-95}, publisher = {Island Press}, organization = {Island Press}, address = {Washington, D.C}, abstract = {In this review, we will use our experiences and our ongoing collaborations to describe an approach that links new concepts regarding ecosystem dynamics to science, management and restoration activities in rangelands. First, we will review some novel elements and ideas connected to resilience theory that mark the evolution of an increasingly integrated paradigm for rangeland ecology. Lastly, we will present a sequence of science and management activities that we feel will allow the paradigm to gain traction in real-world management. It should be noted that our ideas are, in many cases, a work in progress and our hope is that readers are inspired to look more deeply into them, or to develop their own approaches.}, keywords = {ecology, models, paradigm, restoration}, author = {Brandon T Bestelmeyer and Kris Havstad and Damindsuren, B. and G. Han and Joel R. Brown and Jeffrey E. Herrick and Caitriana Steele and Debra C. Peters} } @conference {50076, title = {Rangelands: Changes to improve the quality and performance of an important SRM journal}, booktitle = {62nd Society for Range Management Annual Meeting}, year = {2009}, month = {02/2009}, pages = {2000-14}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Alb., NM}, abstract = {

In 2008, an effort to improve the quality and financial performance of the journal RANGELANDS was begun. Reviews by the Society for Range Management (SRM) Board of Directors (BOD) appointed RANGELANDS Task Force (RTF) and the Advisory Council identified aspects of RANGELANDS critical to membership satisfaction: quality of publication, frequency of publication, subject matter. The RTF Report also identified opportunities for improved financial performance. As a result of the reports and discussion among the membership, the SRM BOD directed the RANGELANDS editor and steering committee to implement changes to RANGELANDS. Those changes include: 1. ensure that all manuscripts submitted to RANGELANDS are subjected to peer review under the direction of the editor; 2. seek more support from external sources for the publication of relevant, special-theme issues with invited authors to offset publication costs; 3. increase the amount of advertising, and; 4. work with publishers to reduce overhead costs. These changes are currently being implemented. The authors will be available to discuss further changes with membership to improve the quality and performance of this vital SRM communication instrument.

}, keywords = {abstract, rangelands, RTF, SRM, SRM journal}, author = {Joel R. Brown and E.L. Fredrickson} } @proceedings {50075, title = {Rotational grazing systems and grazing management research: Mapping the future}, year = {2009}, month = {December 13-16, }, pages = {CDROM}, address = {Sparks, NV}, abstract = {A recent publication reviewed a substantial amount of evidence generated from a geographically diverse effort by university and agency scientists over the past 6 decades to vestigate the impacts of rotational grazing on fundamental rangeland ecological processes. Their findings, and others as well, clearly indicate that varying frequency and intensity of defoliation by rotating grazing livestock does not significantly affect plant or animal production when other factors (stocking rate, season of use etc) are held constant. However, many producers, advisors and researchers have substantial observational evidence that rotational grazing can be an important tool in achieving ranch level goals. This symposium was organized to examine the current state of the knowledge, the range of objectives and goals that producers and conservation programs may have beyond production and opportunities for improving the transfer of research information among scientists, policy makers and producers.}, url = {/files/bibliography/10-010.pdf}, author = {Joel R. Brown and J. D. Derner and J.P. Dobrowolski and Kris Havstad} } @conference {50111, title = {Rangeland remote sensing applications with unmanned aerial systems (UAS) in the national airspace: challenges and experiences.}, booktitle = {American Society for Photogrammetry and Remote Sensing (ASPRS) Annual Conference}, year = {2009}, month = {03/2009}, address = {Baltimore, MD}, abstract = {

In recent years, civilian applications of unmanned aerial systems (UAS) have increased considerably due to their greater availability and the miniaturization of sensors, GPS, inertial measurement units, and other hardware. UAS are well suited for rangeland remote sensing applications, because of the remoteness and low population density of rangelands, and the need of land management agencies to monitor and assess millions of acres of rangeland, a task that is not feasible with ground monitoring techniques alone. While UAS offer reduced operational costs, faster deployment, and more flexibility than piloted aircraft, the operator also has to conform to the Federal Aviation Administrations\’s (FAA) regulations on operating a UAS in the National Airspace, limiting the area and altitude of the UAS mission. We report here on 1) our experiences with obtaining Certificates of Authorization to operate a UAS for the purpose of image acquisition for rangeland monitoring, 2) on the UAS mission, and 3) on image processing and analysis. We acquired 6-cm resolution true color aerial photography over rangelands in southern New Mexico and southwestern Idaho. Concurrently, field measurements of vegetation were collected. The imagery was orthorectified, mosaicked, and analyzed using object-based image analysis. Geometric and classification accuracies were sufficient for rangeland monitoring and assessment purposes, and allowed for mapping the structure and patterns of vegetation and soil in great detail. The results show that UAS are a viable tool for rangeland monitoring, given the current constraints of FAA regulations. Those regulations are in flux, and it is anticipated that in the future, policies for UAS operations will be implemented, including the separation of large and small UAS.

}, keywords = {abstract, National Airspace, remote sensing, UAS, unmanned aerial systems}, author = {Andrea S. Laliberte and A. Rango and Craig Winters and Connie J. Maxwell and A. L. Slaughter} } @article {50119, title = {A retention index calculator simplifies identification of plant volatile organic compounds}, journal = {Phytochemical Analysis}, volume = {20}, year = {2009}, month = {August 2009}, pages = {378-384}, abstract = {

Plant volatiles (PVOCs) are important targets for studies in natural products, chemotaxonomy and biochemical ecology. The complexity of PVOC profiles often limits research to studies targeting only easily identified compounds. With the availability of mass spectral libraries and recent growth of retention index (RI) libraries, PVOC identification can be achieved using only gas chromatography coupled to mass spectrometry (GCMS). However, RI library searching is not typically automated, and until recently, RI libraries were both limited in scope and costly to obtain. Objective is to automate RI calculation and lookup functions commonly utilized in PVOC analysis. Formula required for calculating retention indices from retention time data were placed in a spreadsheet along with lookup functions and a retention index library. Retention times obtained from GCMS analysis of alkane standards and Koeberlinia spinosa essential oil were entered into the spreadsheet to determine retention indices. Indices were used in combination with mass spectral analysis to identify compounds contained in Koeberlinia spinosa essential oil. Eighteen compounds were positively identified. Total oil yield was low, with only 5 ppm in purple berries. The most abundant compounds were octen-3-ol and methyl salicylate. The spreadsheet accurately calculated RIs of the detected compounds. The downloadable spreadsheet tool developed for this study provides a calculator and RI library that works in conjunction with GCMS or other analytical techniques to identify PVOCs in plant extracts.

}, keywords = {biochemical, chemotaxonomy, ecology, essential oil, gas chromatography, Koberlinia spinosa, kovatis index, phytochemical analysis, Plant volatiles, PVOC}, doi = {10.1002/pca.1137}, url = {/files/bibliography/09-020.pdf}, author = {M.E. Lucero and Richard E. Estell and M.R. Tellez and E.L. Fredrickson} } @article {50134, title = {The rise of the mesopredator}, journal = {Bioscience}, volume = {59}, year = {2009}, month = {October 2009}, pages = {779-791}, abstract = {Apex predators have experienced catastrophic declines throughout the world due to human persecution and habitat loss. These collapses in top predator populations are commonly associated with dramatic increases in the abundance of smaller predators. Known as {\textquoteleft}mesopredator release,{\textquoteright} this trophic interaction has been recorded across a range of communities and ecosystems. Mesopredator outbreaks often lead to declining prey populations, sometimes destabilizing communities and driving local extinctions. We present an overview of mesopredator release and illustrate how its underlying concepts can be used to improve predator management in an increasingly fragmented world. We also examine shifts in North American carnivore ranges during the past 200 years and show that 60\% of mesopredator ranges have expanded, whereas all apex predator ranges have contracted. Understanding how best to predict and manage mesopredator release has become urgent as mesopredator outbreaks increasingly result in high ecological, economic, and social costs around the world.}, keywords = {apex, journal, mesopredator, predators}, url = {/files/bibliography/09-024.pdf}, author = {Prugh, L.R. and Stoner, C.J. and Epps, C.W. and Bean, W.T. and Ripple, W.J. and Andrea S. Laliberte and Brashares, J.S.} } @proceedings {50168, title = {The regional ecology of alternative states and thresholds: Strategies for ecological site descriptions}, volume = {1}, year = {2008}, month = {June 30 -July 5,}, pages = {644}, publisher = {Guangdong People{\textquoteright}s Publishing House}, address = {Hohhot, China}, abstract = {Land dynamics, ecosystem resilience, and the interaction of management decisions with them vary significantly across space. One-size-fits-all applications across distinct land types have been responsible for many failures in rangeland management. Ecological Site Descriptions (ESDs) and similar land unit classification systems specify the characteristics of different land areas associated with variation in rangeland potential, ecological dynamics, vulnerabilities, and monitoring needs. State-and-transition models (STMs) embedded within ESDs specify the plant community phases, alternative states, and characteristics of thresholds observed within particular land areas. In spite of considerable conceptual advances with regard to general STM structure and mechanisms, strategies for data-driven development of ESDs and STMs have been poorly developed.}, keywords = {ecological side descritions, ESD, state-and-transition, STM}, author = {Brandon T Bestelmeyer and A.J. Tugel and G. Peacock and D. Robinett and D.D. Briske and T.K. Stringham and P. L. Shaver and Joel R. Brown and Jeffrey E. Herrick and H. Sanchez and Kris Havstad} } @article {50173, title = {Recommendations for development of resilience-based state-and-transition models}, journal = {Rangeland Ecology and Management}, volume = {61}, year = {2008}, note = {//NONE//LTER V//entered 07/28/2008}, month = {2008}, pages = {359-367}, abstract = {

The objective of this paper is to recommend conceptual modifications for incorporation in state-and-transition models (STMs) to link this framework explicitly to the concept of ecological resilience. Ecological resilience describes the amount of change or disruption that is required to transform a system from being maintained by one set of mutually reinforcing processes and structures to a different set of processes and structures (e.g., an alternative stable state). In light of this concept, effective ecosystem management must focus on the adoption of management practices and policies that maintain or enhance ecological resilience to prevent stable states from exceeding thresholds. Resilience management does not exclusively focus on identifying thresholds per se, but rather on within-state dynamics that influence state vulnerability or proximity to thresholds. Resiliencebased ecosystem management provides greater opportunities to incorporate adaptive management than does threshold-based management because thresholds emphasize limits of state resilience, rather than conditions that determine the probability that these limits will be surpassed. In an effort to further promote resilience-based management, we recommend that the STM framework explicitly describe triggers, at-risk communities, feedback mechanisms, and restoration pathways and develop process-specific indicators that enable managers to identify at-risk plant communities and potential restoration pathways. Two STMs representing different ecological conditions and geographic locations are presented to illustrate the incorporation and application of these recommendations. We anticipate that these recommendations will enable STMs to capture additional ecological information and contribute to improved ecosystem management by focusing attention on the maintenance of state resilience in addition to the anticipation of thresholds. Adoption of these recommendations may promote valuable dialogue between researchers and ecosystem managers regarding the general nature of ecosystem dynamics.

Resumen

El objetivo de este documento es recomendar las modificaciones conceptuales para la incorporaci{\'o}n en los modelos estado-y-transici{\'o}n (STMs) para ligar expl{\'\i}citamente este marco con el concepto de resistencia ecol{\'o}gica. La resistencia ecol{\'o}gica describe la cantidad de cambio o de interrupci{\'o}n que se requiere para transformar un sistema mantenido con sus procesos y estructuras mutuas a un sistema diferente (ej. un estado estable alternativo). Bas{\'a}ndose en esta idea, el manejo eficaz del ecosistema debe centrarse en la adopci{\'o}n de pr{\'a}cticas de manejo y reglamentos que mantengan o promuevan la resistencia ecol{\'o}gica para evitar que los estados estables excedan los umbrales. El manejo de la resistencia no se centra exclusivamente en la identificaci{\'o}n de umbrales por s{\'\i} mismo, sino en las din{\'a}micas dentro del-estado que influencian vulnerabilidad o proximidad del estado a los umbrales. El manejo del ecosistema basado en la resistencia proporciona mayores oportunidades de incorporar a un manejo adaptativo que el manejo basado en umbrales debido a que los umbrales acent{\'u}an los l{\'\i}mites de resistencia del estado, en lugar de las condiciones que determinan la probabilidad de que estos l{\'\i}mites sean sobrepasados. En un esfuerzo para promover aun m{\'a}s all{\'a} el manejo basado en la resistencia, recomendamos que el marco del STM describa expl{\'\i}citamente causas, comunidades en riesgo, mecanismos de regeneraci{\'o}n y v{\'\i}as para la restauraci{\'o}n y desarrollo de indicadores que permitan a los encargados identificar comunidades de plantas en riesgo y v{\'\i}as potenciales para su restauraci{\'o}n. Dos STM que representan diversas condiciones ecol{\'o}gicas y localizaciones geogr{\'a}ficas se presentan para ilustrar la incorporaci{\'o}n y el uso de estas recomendaciones. Anticipamos que estas recomendaciones permitir{\'a}n a STM capturar la informaci{\'o}n ecol{\'o}gica adicional y contribuir a un mejor manejo del ecosistema poniendo atenci{\'o}n en el mantenimiento del estado de resistencia adem{\'a}s de la anticipaci{\'o}n de umbrales. La adopci{\'o}n de estas recomendaciones puede promover un valioso di{\'a}logo entre investigadores y encargados del los ecosistemas con respecto a la din{\'a}mica del ecosistema.

}, keywords = {article, ecosystem management, resilience-based, journal, management, resilience-based, model, ecological resilience, model, state and transition}, doi = {10.2111/07-051.1}, url = {files/bibliography/JRN00508.pdf}, author = {D.D. Briske and Brandon T Bestelmeyer and T.K. Stringham and P. L. Shaver} } @conference {50172, title = {Resilience-based application of state-and-transition models}, booktitle = {Society for Range Management Annual Meeting}, series = {Building Bridges: Grasslands to Rangelands}, year = {2008}, month = {January 26-31, 2}, pages = {1657}, address = {Louisville, KY}, abstract = {We recommend that several conceptual modifications be incorporated into the state-and-transition model (STM) framework to: 1) explicitly link this framework to the concept of ecological resilience, 2) direct management attention away from thresholds and toward the maintenance of state resilience, and 3) enhance the ability of STMs to capture a broader set of relevant ecological information to support ecosystem management. Ecological resilience describes the amount of change or disruption that is required to transform a system from being maintained by one set of mutually reinforcing processes and structures to a different set of processes and structures (e.g., alternative stable state). Effective ecosystem management must focus on the adoption of management practices and policies that maintain or enhance ecological resilience to prevent stable states from exceeding potential thresholds. In this context, resilience management does not focus on thresholds per se, but rather on within-state dynamics that influence resilience and state proximity and vulnerability to thresholds. Resilience-based ecosystem management provides greater opportunities to incorporate adaptive management than does threshold-based management because thresholds specifically define the limits of state resilience, rather than the conditions that determine the likelihood that these limits will be surpassed. We recommend that the STM framework incorporate triggers, at-risk communities, feedback mechanisms, and restoration pathways and develop process-specific indicators that enable managers to identify at-risk plant communities and potential restoration pathways.}, keywords = {resilience-based, state-and-transition, STM}, author = {D.D. Briske and Brandon T Bestelmeyer and T.K. Stringham and P. L. Shaver} } @proceedings {50178, title = {Rangeland ecology and management in a changing world}, volume = {1}, year = {2008}, month = {June 30 - July 5}, pages = {41-45}, publisher = {Guangdong People{\textquoteright}s Publishing House}, address = {Hohhot, China}, abstract = {Rangeland ecological science and management over the past century has emphasized external human actions to supplement and direct natural ecological processes in the hope of achieving sustained production. The focus has usually been on an improve efficiency of production, generally achieved by adding fossil fuel based input, to increase consistency of harvest. The results have been relatively benign in the more mesic and fertile rangelands and unsuccessful to disastrous in the more arid and infertile areas. We suggest a broader view of the interactions of humans and rangelands, one that included people as a vital component within the system, might be a more realistic approach to achieving economic, ecological and social sustainability. An increase emphasis is necessary to develop new tools for capturing, organizing and communicating information and to provide testable hypotheses that can advance rangeland ecological science and management.}, keywords = {ecological disturbance, ecological site descriptions, multiscale management, state and transition models}, url = {/files/bibliography/08-022.pdf}, author = {Joel R. Brown and Brandon T Bestelmeyer and Kris Havstad} } @article {50176, title = {Rangelands and climate change: A synthesis and challenges}, journal = {Rangelands}, volume = {30}, number = {3}, year = {2008}, month = {June 30, 2008}, pages = {52-53}, abstract = {

Climate change, along with other aspects of global change, represents a great challenge to rangeland management in the coming century. Coping with this challenge requires collaboration among scientists, managers and policy makers to develop new tools and management systems. This collaboration should focus on meeting the need for 1) improved prediction of changes in climate and the subsequent effects on rangeland ecosystems at relevant spatial scales, 2) integrated monitoring systems and 3) the necessity of managers to respond with unprecedented speed and flexibility to changes in their operating environment.

}, keywords = {climate change, rangelands}, doi = {10.2111/1551-501X(2008)30[52:RACCAS]2.0.CO;2}, url = {/files/bibliography/08-021.pdf}, author = {Joel R. Brown and Thorpe, J.} } @article {50175, title = {Resolving critical issues for the development of ecological site descriptions: Summary of a symposium}, journal = {Rangelands}, volume = {30}, year = {2008}, month = {08/2008}, pages = {16-18}, chapter = {16}, abstract = {

The concepts, methods and procedures for describing rangelands help define the profession of range management. None of these is more important than the system for dividing rangelands into spatially distinct units for the purpose of classifying and managing. Range Sites and Range Condition and the ecological concepts on which they were based dominated research, policy and application virtually from the time SRM was formed (1948) until the late 1990s. In 1997, the revised version of the NRCS Range and Pasture Handbook first referred to Ecological Site Descriptions (ESDs) and gave basic guidance on definitions and procedures for implementation. The change from Range Sites to Ecological Sites is representative of two important changes in the profession: the incorporation of nonequilibrium ecology to describe rangeland dynamics in some ecosystems and the expansion of the array of ecosystem services provided by all rangelands.

}, keywords = {ecological site descriptions, ESD, journal}, doi = {10.2111/1551-501X(2008)30[16:RCIFTD]2.0.CO;2}, url = {/files/bibliography/08-053.pdf}, author = {Joel R. Brown and Brandon T Bestelmeyer} } @article {50182, title = {Remote sensing of woody shrub cover in desert grasslands using MISR with a geometric-optical canopy reflectance model}, journal = {Remote Sensing of Environment}, volume = {112}, number = {112}, year = {2008}, month = {01/2008}, pages = {19-34}, chapter = {19}, abstract = {

A new method is described for the retrieval of fractional cover of large woody plants (shrubs) at the landscape scale using moderate resolution multiangle remote sensing data from the Multiangle Imaging SpectroRadiometer (MISR) and an hybrid geometric-optical (GO) canopy reflectance model. Remote sensing from space is the only feasible method for regularly mapping woody shrub cover over large areas, an important application because extensive woody shrub encroachment into former grasslands has been seen in arid and semiarid grasslands around the world during the last 150 years. The major difficulty in applying GO models in desert grasslands is the spatially dynamic nature of the combined soil and understory background reflectance: the background is important and cannot be modeled as either a Lambertian scatterer or by using a fixed bidirectional reflectance distribution function (BRDF). Candidate predictors of the background BRDF at the Sun-target-MISR angular sampling configurations included the volume scattering kernel weight from a Li-Ross BRDF model; diffuse brightness (rho 0) from the Modified Rahman-Pinty-Verstraete (MRPV) BRDF model; other Li- Ross kernel weights (isotropic, geometric); and MISR near-nadir bidirectional reflectance factors (BRFs) in the blue, green, and near infra-red bands. The best method was multiple regression on the weights of a kernel-driven model and MISR nadir camera blue, green, and near infra-red bidirectional reflectance factors. The results of forward modeling BRFs for a 5.25 km2 area in the USDA, ARS Jornada Experimental Range using the Simple Geometric Model (SGM) with this background showed good agreement with the MISR data in both shape and magnitude, with only minor spatial discrepancies. The simulations were shown to be accurate in terms of both absolute value and reflectance anisotropy over all 9 MISR views and for a wide range of canopy configurations (r2=0.78, RMSE = 0.013, N = 3969). Inversion of the SGM allowed estimation of fractional shrub cover with a root mean square error (RMSE) of 0.03 but a relatively weak correlation (r2=0.19) with the reference data (shrub cover estimated from high resolution IKONOS panchromatic imagery). The map of retrieved fractional shrub cover was an approximate spatial match to the reference map. Deviations reflect the first-order approximation of the understory BRDF in the MISR viewing plane; errors in the shrub statistics; and the 12 month lag between the two data sets.

}, keywords = {BRDF, canopy reflectance modeling, MISR, multi-angle remote sensing}, doi = {10.1016/j.rse.2006.04.023}, url = {/files/bibliography/08-001.pdf}, author = {M. Chopping and L. Su and A. Rango and J. V. Martonchik and Debra C. Peters and Andrea S. Laliberte} } @article {50191, title = {Is rangeland health relevant to Mongolia?}, journal = {Rangelands}, volume = {30}, year = {2008}, month = {August 2008}, pages = {25-29}, abstract = {

Approximately 800,000 of Mongolia{\textquoteright}s 2.5 million people depend directly on livestock production and rangelands for their livelihood. Overgrazing is widespread in the western provinces and near the capital city of Ulaanbaatar, while forage is often underutilized in eastern parts of the country. The rangeland health concept is based on the assumption that the sustainability of all environmental services, including livestock forage production, depend on limiting soil erosion and degradation, effectively capturing, storing and releasing water, and on maintaining productive, resilient biological communities. To be relevant to Mongolian herders and policymakers, rangeland health must be integrated into a management framework that explicitly includes maximizing long-term forage production as a primary objective. This article presents a 4-step management framework that shows how rangeland health assessments and monitoring might be applied in developing countries like Mongolia, where optimizing long-term forage production is the primary management objective. These preliminary attempts to adapt and apply the rangeland health concept, and specifically the IIRH protocol to Mongolia, suggest that additional work is needed in three areas: 1) developing more explicit links between the rangeland health attributes and specific land uses and values, including forage production; 2) anticipating new threats, such as invasive species, which may influence rangeland sustainability; and 3) increasing our understanding of how resilience varies throughout the country.

}, keywords = {journal article, Mongolia, overgrazing, rangeland health}, doi = {10.2111/1551-501X(2008)30[25:IRHRTM]2.0.CO;2}, url = {/files/bibliography/08-030.pdf}, author = {Damdinsuren, G. and Jeffrey E. Herrick and D.A. Pyke and Brandon T Bestelmeyer and Kris Havstad} } @article {50202, title = {Resource regulation by a twig-girdling beetle has implications for desertification}, journal = {Ecological Entomology}, volume = {33}, year = {2008}, note = {//USDA//LTER V//entered 04/03/2008}, month = {2008}, pages = {161-166}, abstract = {

1. Resource regulation by insects is the phenomenon by which herbivory enhances resources for the progeny of the herbivore. This report provides an example of resource regulation with implications for desertification in the Chihuahuan Desert of North America.

2. Female Oncideres rhodosticta beetles chew girdles around mesquite ( Prosopis glandulosa ) stems before ovipositing in those stems. The mesquite plants respond by producing compensatory stems below the girdle. Mesquite volume was significantly correlated with the total number of beetle girdles across a suite of low shrub density grassland and high shrub density dune sites, and plants in dune sites had more old and new girdles than mesquite in grasslands.

3. Smaller, younger shrubs in grassland responded more vigorously to girdling than did larger, older shrubs in dune landscapes. Stems on shrubs within grassland produced significantly more and longer compensatory stems per girdle than stems on shrubs in dunes. Soil capture by individual plants positively correlated with stem density, and stem density is increasing in the younger plants as a response to beetle damage.

4. This study suggests that the interaction between O. rhodosticta and mesquite is an example of resource regulation that increases the stem density and soil capture ability of mesquite. Because the conversion of productive grasslands to mesquite dune landscapes is one of the most important drivers of desertification in the Chihuahuan Desert, feedbacks between organisms that promote an increase in the size and soil capture ability of mesquite may exacerbate desertification.

}, keywords = {arthropod, mesquite, arthropod, Prosopis, article, Chihuahuan Desert, desertification, resource regulation, journal, landscape conversion, Oncideres, plant-herbivore interactions, Prosopis}, doi = {10.1111/j.1365-2311.2007.00928.x}, url = {files/bibliography/JRN00511.pdf}, author = {B.D. Duval and Walter G. Whitford} } @article {50203, title = {Resource regulation by a twig-girdling beetle has implications for desertification}, volume = {33}, year = {2008}, month = {2008}, pages = {161-166}, abstract = {

1. Resource regulation by insects is the phenomenon by which herbivory enhances resources for the progeny of the herbivore. This report provides an example of resource regulation with implications for desertification in the Chihuahuan Desert of North America. 2. Female Oncideres rhodosticta beetles chew girdles around mesquite (Prosopis glandulosa ) stems before ovipositing in those stems. The mesquite plants respond by producing compensatory stems below the girdle. Mesquite volume was significantly correlated with the total number of beetle girdles across a suite of low shrub density grassland and high shrub density dune sites, and plants in dune sites had more old and new girdles than mesquite in grasslands. 3. Smaller, younger shrubs in grassland responded more vigorously to girdling than did larger, older shrubs in dune landscapes. Stems on shrubs within grassland produced significantly more and longer compensatory stems per girdle than stems on shrubs in dunes. Soil capture by individual plants positively correlated with stem density, and stem density is increasing in the younger plants as a response to beetle damage. 4. This study suggests that the interaction between O. rhodosticta and mesquite is an example of resource regulation that increases the stem density and soil capture ability of mesquite. Because the conversion of productive grasslands to mesquite dune landscapes is one of the most important drivers of desertification in the Chihuahuan Desert, feedbacks between organisms that promote an increase in the size and soil capture ability of mesquite may exacerbate desertification.

}, doi = {10.1111/j.1365-2311.2007.00928.x}, url = {/files/bibliography/08-050.pdf}, author = {B.D. Duval and Walter G. Whitford} } @conference {50235, title = {Rodent density and the landscape of fear in the Chihuahuan Desert}, booktitle = {93rd Ecological Society of America Annual Meeting}, series = {93rd ESA Annual Meetings}, year = {2008}, month = {August 3-8, 2008}, pages = {COS 118-8}, abstract = {Small mammals in desert environments are important links in ecosystem energy flow, with their densities often effecting the abundance of their primarily predators. Granivorous small mammals also affect seed dispersal and can shape vegetation characteristics. Consequently, factors affecting small mammal abundance are important in understanding community and ecosystem structure and dynamics. Small mammal abundance has been attributed to levels of precipitation/primary productivity (bottom up) and/or removal by predation (top down). However, small mammal abundance can vary greatly over the landscape in relatively short (< 5 km) distances. Similarities in precipitation amounts and predator abundance on this small scale do not explain this within-landscape variation in abundance. However, on this scale, habitat heterogeneity can be high. Under the landscape of fear model, such habitat heterogeneity can result in proportionally different amounts of safe vs risky habitat and consequently, predation risk among adjacent areas. We predicted that density of small mammals in an area is inversely related to the proportion of risky habitat/level of predation risk of an area. We tested this prediction with kangaroo rats (Dipodomys spp.) in two geographically separate areas of the Chihuahaun Desert: Mapimi Biosphere reserve in Durango Mexico and the Jornada Experimental range in New Mexico. We measured giving up densities (GUDs) in 8 distinct areas of similar shrub/grass habitat with different densities of kangaroo rats. GUD{\textquoteright}s were measured with commercial 50 x30 x 10 cm aluminum buffet trays containing 3 kg of sand and 4 g of millet seed. The specific prediction was that GUDs would be inversely related to kangaroo rat densities.}, keywords = {abstract, Chihuahuan Desert, desnity, rodent}, author = {John W. Laundre and Lucina Hern{\'a}ndez and A. Campanella and D. K. James} } @inbook {50257, title = {The Role of Disturbances in Shortgrass Steppe Community and Ecosystem Dynamics}, booktitle = {Long-Term Ecological Research in the Shortgrass Steppe}, year = {2008}, month = {September 2008}, pages = {84-118}, abstract = {The disturbance regime of shortgrass steppe ecosystems consists of a number of different types of disturbances operating over a range of spatial and temporal scales. Each disturbance type has its own set of characteristics including size, frequency of occurrence, intensity, and location by soil texture, topographic position, and grazing intensity by cattle. These characteristics result in different short-term, localized effects on plant as well as long-term, broad-scale effects as the disturbances accumulate through time. Although successional studies have been conducted in these grasslands for over a century, our understanding of the role of different kinds of disturbances in generating and maintaining patterns in vegetation and species dominance in shortgrass ecosystems has developed only since the 1980{\textquoteright}s. Our current view of the role of disturbance is a dynamic one where the recovery of vegetation depends upon interactions among disturbance characteristics and the life history traits of plants. This gap dynamics conceptualization provides an alternative view of vegetation dynamics compared to traditional successional models based on Clements. Much of the recent work on disturbances in the shortgrass steppe has focused on the relationships between disturbance characteristics and plant life history traits in order to test these different models. This chapter describes the various alternative models, and summarizes the literature on the disturbance regime of shortgrass steppe ecosystems and the responses of vegetation and soils following different kinds of disturbances.}, author = {Debra C. Peters and W. K. Lauenroth and Ingrid C. Burke} } @article {50259, title = {Relative importance of glacier contributions to water supply in a changing climate}, journal = {World Resource Review}, volume = {20}, number = {(3)}, year = {2008}, note = {Original submission: Intern{\textquoteright}tl Cong on Modeling \& Simulation Proccedings 7-30-07; resubmitted to World Resource Review 9/25/2007}, month = {August 8, 2008}, pages = {487-503}, abstract = {

The Snowmelt Runoff Model (SRM) was designed for simulation, forecasting, and future assessments, such as the effects of climate change. The most recent version of SRM uses the Microsoft Windows operating system and operates efficiently in the PC environment. A formalized algorithm for assessing the effects of climate change on runoff is included in the model. SRM parameters are predetermined from actual measurements or from hydrological experience and, therefore, calibration is not necessary. This deterministic approach allows the parameters to be altered with regard to a changed future climate. SRM variables of daily temperature, precipitation, and snow covered area are also easily acquired. SRM allows contributions of snow, rain, and glacier ice to be separately computed for a present year and for a future climate-changed year. In basins with a significant glacier melt component, such as the Illecillewaet Basin in British Columbia, as the climate warms, the glacier runoff component increases. Of course, when the glacier volume is depleted to a certain point, the glacier areas will start to decline and the valuable glacier melt component will also be diminished.

}, keywords = {glacier melt, global warming, snowmelt runoff modeling, water resources planning, water supply}, url = {/files/bibliography/08-027.pdf}, author = {A. Rango and J. Martinec and R. T. Roberts} } @conference {50268, title = {The remote characterization of vegetation using Unmanned Aerial Vehicle photography}, booktitle = {AGU 2008 Fall Meeting}, series = {AGU 2008 Fall Meetings}, year = {2008}, month = {December 15-19, }, pages = {B32A-01}, address = {San Francisco, CA}, abstract = {Unmanned Aerial Vehicles (UAVs) can fly in place of piloted aircraft to gather remote sensing information on vegetation characteristics. The type of sensors flown depends on the instrument payload capacity available, so that, depending on the specific UAV, it is possible to obtain video, aerial photographic, multispectral and hyperspectral radiometric, LIDAR, and radar data. The characteristics of several small UAVs less than 55lbs (25kg)) along with some payload instruments will be reviewed. Common types of remote sensing coverage available from a small, limited-payload UAV are video and hyperspatial, digital photography. From evaluation of these simple types of remote sensing data, we conclude that UAVs can play an important role in measuring and monitoring vegetation health and structure of the vegetation/soil complex in rangelands. If we fly our MLB Bat-3 at an altitude of 700ft (213m), we can obtain a digital photographic resolution of 6cm. The digital images acquired cover an area of approximately 29,350sq m. Video imaging is usually only useful for monitoring the flight path of the UAV in real time. In our experiments with the 6cm resolution data, we have been able to measure vegetation patch size, crown width, gap sizes between vegetation, percent vegetation and bare soil cover, and type of vegetation. The UAV system is also being tested to acquire height of the vegetation canopy using shadow measurements and a digital elevation model obtained with stereo images. Evaluation of combining the UAV digital photography with LIDAR data of the Jornada Experimental Range in south central New Mexico is ongoing. The use of UAVs is increasing and is becoming a very promising tool for vegetation assessment and change, but there are several operational components to flying UAVs that users need to consider. These include cost, a whole set of, as yet, undefined regulations regarding flying in the National Air Space(NAS), procedures to gain approval for flying in the NAS(FAA Certificate of Authorization), and training(remote control piloting, UAV-specific instruction, FAA ground school and testing, FAA observer procedures, FAA medical Class 2 exam, and a private pilot{\textquoteright}s license). The relevance and need of all these to developing a UAV capability will be explained. While working through the necessary requirements above, we have also learned that we need to know how to handle extremely large and easily acquired data sets as well as to develop tools to orthorectify and mosaic individual UAV images for analysis.}, keywords = {remote sensing, UAV, Unmanned Aerial Vehicles}, author = {A. Rango and Andrea S. Laliberte and Craig Winters and Connie J. Maxwell and Caitriana Steele} } @inbook {50267, title = {Remote Sensing of the Snowpack}, booktitle = {Principles of Snow Hydrology}, year = {2008}, month = {July 2008}, pages = {118-145}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, chapter = {5}, address = {Cambridge, NY}, abstract = {

Because of vast differences in the physical properties of snow and other natural surfaces, the occurrence of snow in a drainage basin can cause significant changes in energy and water budgets. As an example, the relatively high albedo of snow reflects a much higher percentage of incoming solar, shortwave radiation than snow-free surfaces (80\% or more for relatively new snow as opposed to roughly 15\% or less for snow-free vegetation). This can be important because snow may cover up to 53\% of the land surface in the northern hemisphere and up to 44\% of the world\’s land areas at any one time. The visible portion (0.4 to 0.7 \µm) of the electromagnetic spectrum can be used to map the percentages of a basin covered by snow because of the differences in reflectance of snow and snow-free areas. The thermal infrared portion of the spectrum (8-14 \µm) can detect snowpack surface temperature variability in space and time which can be directly linked to the presence of water in the snowpack and perhaps to snowmelt. Although, in widely disparate portions of the spectrum the gamma radiation (3 divided by 10 to the sixth power to 3 divided by 10 to the fifth power \µm) and the microwave radiation (1 mm 1 m) bands can be used in similar ways to detect the snowpack water equivalent using the attenuation of the relevant radiation by the snowpack itself. A combination of two different remote sensors can at certain times increase information available about the snowpack. With recent technological advances in data processing and transmission, data and derived snow and ice products from many current sensors are available to the hydrologic community in near real time (e.g., within 6 to 24 hours of satellite overpass).

}, keywords = {drainage basin, energy, remote sensing, snow, snowmelt, snowpack, water}, url = {http://www.cambridge.org/us/academic/subjects/earth-and-environmental-science/hydrology-hydrogeology-and-water-resources/principles-snow-hydrology}, author = {A. Rango and D. DeWalle} } @article {50260, title = {Role of aerial photos in compiling a long-term remote sensing data set}, journal = {Journal of Applied Remote Sensing}, volume = {2}, year = {2008}, month = {10/2008}, pages = {023541}, abstract = {

Long-term data sets are important in the fields of ecology, hydrology, rangeland science, and geography. Remote sensing is an especially important component of such studies when spatial and temporal capabilities are important considerations. In many cases, satellite remote sensing is not adequate because of resolution or length of observation considerations. However, aerial photography, which extends back into the mid 1930s, is often overlooked. In order to find relevant imagery, considerable effort needs to be expended because the aerial photos over a particular study area can be scattered in a large number of archives across the country. Once the photos are assembled, digital scanning, proper documentation, storage, and a searchable data base are necessary to make easy and effective use of the aerial photos. The aerial photo data are of immense value to researchers, natural resource managers, students, and the general public.

}, keywords = {aerial photography, ecology, historic landscape legacies, rangelands, vegetation change}, doi = {10.1117/1.3009225}, url = {/files/bibliography/08-043.pdf}, author = {A. Rango and Andrea S. Laliberte and Craig Winters} } @conference {50274, title = {Remote sensing studies of arid rangelands in the southwestern United States}, booktitle = {Society for Range Management Annual Meeting}, year = {2008}, note = {Submitted by Beltsville Area}, month = {January 26-31, 2}, pages = {1504}, address = {Louisville, KY}, abstract = {The USDA ARS Jornada Experimental Range (Jornada) in southern New Mexico and the Sevilleta National Wildlife Refuge (Sevilleta) in Central New Mexico are Long Term Ecological Research (LTER) sites that provide unique opportunities to study changing rangeland conditions using remote sensing techniques. A research program began in 1995 collecting remotely sensed data from ground, aircraft, and satellite platforms to provide spatial and temporal data on the radiometric, thermal, physical, and vegetative properties of ecosystems (grass, grass/shrub transition, and shrub) typical of arid rangeland of southwestern United States. Data from these different platforms are being used to evaluate the physical and vegetation changes over time and at different scales in these ecosystems. Reflectance and thermal measurements from all platforms indicate that the shrub ecosystems have greater reflectance and are warmer that the grass ecosystems. Comparison of ground (ASD), aircraft (MASTERS), and satellite (ASTER) reflectance measurements showed that they were measuring similar reflectance values for three dates and the three vegetation communities. Reflectance was highest from the shrub and shrub-grass transition communities and lowest from the grass community and was related to the amount of vegetation cover present. This has implications for the energy and water budgets in this region of the Chihuahuan desert where shrub communities with low ground cover are invading and replacing grass communities.}, keywords = {abstract, remote sensing}, author = {Jerry Ritchie and A. Rango and T. J. Schmugge} } @conference {50283, title = {Rangeland monitoring with unmanned aerial vehicles (UAVs)}, booktitle = {Society for Range Management Annual Meetings}, series = {Proceedings of the 2008 Joint Meeting of the Society for Range Mangement and the American Forage and Grazing; Building Bridges: Grasslands to Rangelands}, year = {2008}, month = {01/2008}, address = {Louisville, KY}, abstract = {

Unmanned aerial vehicles (UAVs) have great potential for rangeland management applications, such as monitoring vegetation change, developing grazing strategies, determining rangeland health, and assessing remediation treatment effectiveness. UAVs have several advantages: they can be deployed quickly and repeatedly; they are less costly and safer than piloted aircraft; they are flexible in terms of flying height and timing of missions; and they can obtain imagery at sub-decimeter resolution. This hyperspatial imagery, imagery with a resolution finer than the object of interest, allows for observation of individual plants, patches, gaps, and patterns over the landscape not previously possible. At the Jornada Experimental Range (JER) in New Mexico, ongoing research is aimed at determining the utility of UAVs for rangeland mapping and monitoring. The UAV was flown at 150 m above ground and acquired imagery at approximately 5 cm ground resolution. The images were orthorectified, mosaicked, and classified using an object-based image analysis technique. Overall classification accuracies were in the high 90\% range, and we were able to differentiate multiple soil types and different densities of vegetation. While image acquisition and classification are quite easily accomplished, image rectification and mosaicking are more time consuming due to small image footprints, image distortion and the difficulty of detecting sufficient ground control points. Our efforts are focused on developing and refining a complete and efficient workflow for UAV missions, consisting of flight planning, image acquisition, image rectification and mosaicking, and subsequent image classification.

}, keywords = {rangeland management, UAV, Unmanned Aerial Vehicles}, author = {A. L. Slaughter and Andrea S. Laliberte and A. Rango and Connie J. Maxwell and Craig Winters} } @article {50318, title = {Rotational grazing on rangelands: Reconciliation of perception and experimental evidence}, journal = {Rangeland Ecology and Management}, volume = {61}, year = {2007}, note = {Duplicate of 213934. use 204233 for reporting}, pages = {3-17}, abstract = {

In spite of overwhelming experimental evidence to the contrary, rotational grazing continues to be promoted and implemented as the only viable grazing strategy. The goals of this synthesis are to 1) reevaluate the complexity, underlying assumptions, and ecological processes of grazed ecosystems, 2) qualitatively summarize plant and animal production responses to rotational and continuous grazing, 3) characterize the prevailing perceptions influencing the assessment of rotational and continuous grazing, and 4) attempt to direct the profession toward a reconciliation of perceptions advocating support for rotational grazing systems with that of the experimental evidence. The ecological relationships of grazing systems have been reasonably well resolved, at the scales investigated, and a continuation of costly grazing experiments adhering to conventional research protocols will yield little additional information. Plant production was equal or greater in continuous compared to rotational grazing in 87\% (20 of 23) of the experiments. Similarly, animal production per head and per area were equal or greater in continuous compared to rotational grazing in 92\% (35 of 38) and 84\% (27 of 32) of the experiments, respectively. These experimental data demonstrate that a set of potentially effective grazing strategies exist, none of which have unique properties that set one apart from the other in terms of ecological effectiveness. The performance of rangeland grazing strategies are similarly constrained by several ecological variables establishing that differences among them are dependent upon the effectiveness of management models, rather than the occurrence of unique ecological phenomena. Continued advocacy for rotational grazing as a superior strategy of grazing on rangelands is founded on perception and anecdotal interpretations, rather than an objective assessment of the vast experimental evidence. We recommend that these evidence-based conclusions be explicitly incorporated into management and policy decisions addressing this predominant land use on rangelands.

}, keywords = {continuous grazing, domestic herbivores, grazed ecosystems, grazing management, grazing systems, rangeland management}, url = {/files/bibliography/08-003.pdf}, author = {D.D. Briske and J. D. Derner and Joel R. Brown and S. Fuhlendorf and Teague, W.R. and Kris Havstad and Gillen, R.L. and A.J. Ash and Walter Willms} } @conference {50320, title = {Rodent community landscape ecology in grassland-shrubland ecotones and gradients in the Chihuahuan Desert}, booktitle = {22nd Annual Symposium of U.S. Regional Chapter of International Association of Landscape Ecology}, year = {2007}, month = {April 9-11, 2007}, pages = {p. 21}, address = {Tucson, AZ}, abstract = {It is believed that the abundance and diversity of Chihuahuan Desert rodents increases with shrub encroachment accompanying desertification although grassland specialist species decline with loss of perennial grasses. It has been reported, however, that rodent population responses to spatial variation in habitat are mediated by a complex suite of biotic-abiotic interactions. The consistency of such patterns across a landscape has not been examined. We tested the hypothesis that rodent richness, biomass, and density/abundance were highest in shrub-dominated portions of replicate grassland-shrubland ecotones and across a grassland-shrubland gradient. Rodents were trapped on permanent grids scattered over an area of 200 km2. Mark-recapture procedures were used to estimate population density and the software eCognition to estimate landscape structure using an object-oriented spatial analysis approach. We found that rodent abundance, biomass, and species composition were highly variable and related to the details of vegetation structure across the landscape, rather than being simply positively correlated with shrub cover.}, keywords = {Chihuahuan Desert, diversity, rodent}, author = {A. Campanella and Brandon T Bestelmeyer and G. Roemer and Debra C. Peters} } @conference {50331, title = {Reproduccion del ganado}, booktitle = {Taller de Extension San Carlos}, year = {2007}, month = {August 2007}, abstract = {La determination de prenez es una de las principales herramientas de manejo en el Ganado de came. Le habilidad de determiner prenez proporciona al productor un medio de tomar sus decsiones de seleccion y descartarte en momentos decisivos, enfocando los recursos de la operacion en reporductores confiables. Con experiencia se puede determiner la edad del feto, que nos permite determiner las fecas de paricion para planificar los trabajos apropiados. La determinacion de prenez tambiem facilita major manejo de la alimentacion para conseguir satisfacer los altos requerimientos nutricionales de la gestacion, paricion, lactacion y procreacion. El conocimiento de las fechas de nacimiento puede ser ventaja en la comercializacion de reemplazo de hembras. La majoria de las veces los compradores potenciales, quieren comprar vaquillas prenadas que van a parir coincidiendo con las vacas de su hato actual. El retorno economico de los criadoes es dependiente en el porcentaje de paricion annual y el peso de becerros destetados de ser vendidos. El desafio de los criadores de Ganado es usar las tecnicas de manejo que estimulen la produccion sin aumentar drasticamente los costos de produccion. Una opcion para mejorar la produccion que es eficaz y de costo bajo es por medio de hacer pruebas de prenez anuales yt hacer descarte de vacas subfertiles. La preuba de prenez identificia problemas de infertilidad permitiendo investigacion temprana y tomando un curso de accion que de otra manera no seria possible. La determinacion de prenez tiene poco uso si no se usa esta informacion prar realizar mejores decsisones de manejo. Esta prueba deberia realizarse anualmente para obtener major efectividad en el aumento de la fertilidad del Ganado de carne}, author = {Amy L. Gonzalez} } @proceedings {50373, title = {Relative importance of glacier contributions to streamflow in a changing climate}, year = {2007}, month = {08/2007}, pages = {203-207}, address = {Honolulu, Hawaii}, abstract = {The role of glaciers and snow in climate change-affected runoff is evaluated by taking into account the carryover of runoff and of unmelted snow from one hydrological year to another. This water balance is computed for the present climate and for future climates with changed temperatures and precipitation. With this procedure, the contribution of glaciers to the total runoff and the yearly loss of glacier ice in a warmer climate can be more accurately determined than by just considering the overall increase of annual runoff volume. The Illecillewaet Basin in British Columbia, Canada (1155 km2, 509\–3150 m a.s.l.) was selected for this study because of a significant glacial melt component in the runoff. For a temperature increase of 4\°C, an additional 134.2\•106m3 of today\’s glaciers (in terms of water) in this basin would be melted in a year. This amount would be reduced as the glacier area gradually diminishes in the next decades.}, keywords = {changing climate, climate change effects, glacier, remote sensing, stramflow, water supply and sustainable use, watershed modelling}, url = {/files/bibliography/07-024.pdf}, author = {A. Rango and J. Martinec and R. T. Roberts} } @article {50382, title = {Robust Classification of Animal Tracking Data}, journal = {Computers and Electronics in Agriculture}, volume = {56}, year = {2007}, month = {April 2007}, pages = {46-59}, abstract = {This paper describes an application of the K-means classification algorithm to categorize cow tracking data into various classes of behavior. It is found that even without explicit consideration of biological factors, the clustering algorithm can repeatably resolve cow behavior into two groups corresponding to active and inactive periods. Furthermore, it is shown that this classification is robust to a large range of data sampling intervals. An adaptive data sampling algorithm is suggested for improving the energy efficiency and memory usage of animal tracking equipment.}, keywords = {adaptive sampling, animal tracking, cluster analysis, GPS, sensor networks}, url = {/files/bibliography/07-010.pdf}, author = {Schwager, M. and D.M. Anderson and Butler, Z. and D. Rus} } @conference {50386, title = {Remote sensing of threshold conditions in an arid ecosystem}, booktitle = {Amereican Geophysical Union Fall Meeting}, year = {2007}, month = {December 10-14, }, pages = {B42B-1160}, address = {San Francisco, CA}, abstract = {Land management in the arid southwestern USA increasingly addresses thresholds in response to recent concepts adopted by private and public lands agencies and conservation organizations. Vegetation in arid rangelands typically presents as distinctive mosaics of vegetation patches, which persist in dynamic equilibrium with the abiotic environment and facilitative-competitive interactions between organisms. Theory and observation suggest that as an area approaches a threshold in response to disturbance, there is a concomitant change in the spatial arrangement of vegetation patches. This change is readily identifiable on fine spatial resolution aerial photography or satellite sensor imagery. We propose a classification method for identifying threshold-inducing change in vegetation pattern. To illustrate this method, we have applied an object-oriented, supervised classification to subsets of Quickbird imagery (70 cm ground resolution) over the Jornada basin in southern New Mexico. The imagery covers several land management regimes (private, public, federal) and provides spatial variation in ecosystem conditions. Imagery was first segmented to create fine and coarse resolution image objects. Fine resolution image objects are defined as having within-object spectral homogeneity at the scale of the shrub or single patch of grass or soil. Coarse resolution image objects are defined as containing spectral homogeneity at the scale of the vegetation stand. A classification tree was used to classify coarse resolution image objects to high risk of a threshold, low risk of a threshold, or post-threshold according to the content and spatial arrangement of shrub, grass and soil patches within them. Ground-based monitoring to detect localized threshold conditions across broad management areas is intractable so the use of remote sensing is essential to successful prevention of threshold development.}, keywords = {management, private, public lands, threshold}, author = {Caitriana Steele and Brandon T Bestelmeyer and A. Rango and Phil Smith and Andrea S. Laliberte} } @conference {50391, title = {Restoration of spatial heterogeneity and ecohydrological processes in semi-arid grassland: Influence of timing and landscape context on long-term changes in soil and vegetation}, booktitle = {Ecological Society of America Abstracts}, year = {2007}, month = {August 5, 2007}, pages = {105}, address = {San Jose, CA}, abstract = {The success of ecosystem restoration in semi-arid grasslands is variable and unpredictable. Water retention dikes (7.5-30 cm tall, 50-150 m long) were installed at the Jornada Experimental Range (3-6 dikes/site) in the Chihuahuan Desert from 1975-1981 in an effort to restore ecosystem structure and function. There was little detectable change for several years after installation of the dikes. Compared to nearby reference areas, soil moisture was 20-45\% higher behind the dikes (except TW), even though ponded saturated infiltration rates were 20- 80\% slower behind the dikes. Soil aggregate stability was consistently greater behind the dikes. Clay and silt soil fractions were greater behind the dikes generally, but one site (AT) had the opposite pattern. Differences in soil texture were likely influenced by transport processes and source areas. Percent cover of vegetation behind the dikes was 1.5-3 times the cover at nearby reference areas, but 20 times greater at one site (TW). Plant species richness behind the dikes was about double that in the reference areas, but 6 times greater at one site (TW). Mesquite (Prosopis spp.) and unpalatable shrubs were less dominant behind the dikes, while cover of small shrubs, grasses and forbs was greater than in reference areas. Fertilization with nitrogen and micronutrients increased vegetation cover behind dikes, but not in reference areas. The addition of native grass seed (black grama, Bouteloua eriopoda) allowed establishment of plants in some sandy areas at both dike and reference sites (mainly at DA), but only when other above ground vegetation was removed. Installation of water retention structures was sufficient to initiate the formation of islands of increased resource availability and increased biological productivity, but the development of soil and vegetation interactions was influenced by the local site characteristics, the landscape context, and the rainfall pattern.}, keywords = {ecohydrological, spatial heterogeneity}, author = {S. Tartowski and Jeffrey E. Herrick and A. Rango} } @article {50427, title = {Reconciling Carbon-cycle Concepts, Terminology, and Methods}, journal = {Ecosystems}, volume = {9}, year = {2006}, note = {//Other//LTER IV//entered 08/14/2007}, month = {2006}, pages = {1041-1050}, abstract = {

Recent projections of climatic change have focused a great deal of scientific and public attention on patterns of carbon (C) cycling as well as its controls, particularly the factors that determine whether an ecosystem is a net source or sink of atmospheric carbon dioxide (CO2). Net ecosystem production (NEP), a central concept in C-cycling research, has been used by scientists to represent two different concepts. We propose that NEP be restricted to just one of its two original definitions{\textemdash}the imbalance between gross primary production (GPP) and ecosystem respiration (ER). We further propose that a new term{\textemdash}net ecosystem carbon balance (NECB){\textemdash}be applied to the net rate of C accumulation in (or loss from [negative sign]) ecosystems. Net ecosystem carbon balance differs from NEP when C fluxes other than C fixation and respiration occur, or when inorganic C enters or leaves in dissolved form. These fluxes include the leaching loss or lateral transfer of C from the ecosystem; the emission of volatile organic C, methane, and carbon monoxide; and the release of soot and CO2 from fire. Carbon fluxes in addition to NEP are particularly important determinants of NECB over long time scales. However, even over short time scales, they are important in ecosystems such as streams, estuaries, wetlands, and cities. Recent technological advances have led to a diversity of approaches to the measurement of C fluxes at different temporal and spatial scales. These approaches frequently capture different components of NEP or NECB and can therefore be compared across scales only by carefully specifying the fluxes included in the measurements. By explicitly identifying the fluxes that comprise NECB and other components of the C cycle, such as net ecosystem exchange (NEE) and net biome production (NBP), we can provide a less ambiguous framework for understanding and communicating recent changes in the global C cycle.

}, keywords = {article, autotrophic respiration, ecosystem respiration, gross primary production, heterotrophic respiration, journal, net biome production, net ecosystem carbon balance, net ecosystem exchange, net ecosystem production, net primary production}, doi = {10.1007/s10021-005-0105-7}, url = {files/bibliography/JRN00457.pdf}, author = {F.S. Chapin III and Woodwell, G. M. and J. Randerson and E. B. Rastetter and Lovett, G. M. and Baldocchi, D. D. and Clark, D. A. and M. Harmon and David Schimel and Valentini, R. and Wirth, C. and Aber, J. D. and Cole, J. J. and Goulden, M. L. and Harden, J. W. and Heimann, M. and Howarth, R. W. and Matson, P. A. and A. D. McGuire and Melillo, J. M. and Mooney, H. A. and J. Neff and Houghton, R. A. and Pace, M. L. and Ryan, M. G. and Running, S. W. and O. E. Sala and W. H. Schlesinger and Schulze, E. -D.} } @inbook {50459, title = {Remediation Research in the Jornada Basin: Past and Future}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {278-304}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {14 }, address = {New York, NY}, abstract = {Land degradation in most of the Chihuahuan Desert is characterized by a shift from grass- to shrub-dominated plant communities. Consequently, most remediation efforts are focused on grassland restoration. Early experiments and trials focused on grazing management. Beginning in the 1930{\textquoteright}s and continuing through the 1980{\textquoteright}s, various methods of shrub control were evaluated. Early investigators had an intuitive and practical understanding of the system in which they worked. They saw the individual limitations to grassland recovery and attempted to address them. In order to be more successful than they were, we must begin to work at spatial and temporal scales relevant to the processes we hope to affect and target our interventions to those locations and during those periods when the processes are most susceptible to change. We must also, as the earlier workers did, simultaneously target multiple processes with the objective of increasing the resistance and resilience of the modified ecosystems.}, keywords = {Chihuahuan Desert, Jornada Basin, LTER, synthesis book}, url = {/files/bibliography/06-065.pdf}, author = {Jeffrey E. Herrick and Kris Havstad and A. Rango}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @article {50469, title = {Rangeland Mapping; Ease Classification with an Object-oriented Approach and Satellite Imagery}, journal = {Earth Imaging Journal}, volume = {3}, number = {1}, year = {2006}, month = {2006}, pages = {30-32}, abstract = {

Determining detailed vegetation characteristics to classify arid rangelands often presents unique problems due to the high reflectance of the soil background, a mixture of green and senescent grasses, and the prevalence of shrubs in grasslands. These components can make it difficult to determine the proportion of grass cover. On the Jornada Experimental Range (JER), operated by the U.S. Department of Agriculture Agricultural Research Service near Las Cruces, NM, ongoing research is aimed at determining the relationship between ground-based observations and remotely sensed data.

}, keywords = {object-oriented, rangeland mapping, satellite imagery}, url = {/files/bibliography/06-002.pdf}, author = {Andrea S. Laliberte and A. Rango and E.L. Fredrickson} } @inbook {50477, title = {Regional Setting of 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 = {15-43}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {2}, address = {New York, NY}, abstract = {Within the area around Las Cruces, New Mexico, is a network of studies at the Jornada Experimental Range, the Chihuahuan Desert Rangeland Research Center, and the Desert Soil-Geomorphology Project. All of these areas are in the Jornada Basin except for the area south of the Dona Ana Mountains, which are in the Mesilla Basin. All of these research entities are in the Chihuahuan Desert and this chapter describes the geologic history and development of landscapes that are important elements to our understanding of this ecosystem and its dynamic nature.}, keywords = {development, geologic, history, landscapes, regional, setting, soil-geomorphology}, url = {/files/bibliography/06-053.pdf}, author = {Curtis H. Monger and Greg H. Mack and B. Nolen and L. H. Gile}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @article {50500, title = {Role of Species Diversity and Secondary Compound Complementarity on Diet Selection of Mediterranean Shrubs by Goats}, journal = {Journal of Chemical Ecology}, number = {32}, year = {2006}, month = {May 31, 2006}, pages = {1279-1287}, abstract = {

Goats foraging on Mediterranean shrubs containing secondary compounds (toxins) may consume a variety of shrubs that contain different phytotoxins, thereby increasing shrub intake and avoiding toxicosis. We conducted eight experiments to examine whether goats offered different mixtures of shrubs containing different phytotoxins (tannins and saponins) would consume more shrub biomass than goats offered one shrub a single phytotoxin (tannin or saponin). In the first three experiments, goats fed a mixture of three tannin-rich shrubs (Quercus ilex, Arbutus unedo, and Pistacia lentiscus) ate more foliage than goats offered only one shrub (23.2 vs. 10.7 g/kg BW; 25.2 vs. 13.4 g/kg BW, and 27.9 vs. 7.9 g/kg BW), regardless of tannin concentration in individual shrub species. Goats also consumed more foliage when offered the same three tannin-rich shrubs than when offered the saponin-rich shrub Hedera helix (25.4 vs. 8.0 g/kg BW). However, goats offered a mixture of the same three tannin-rich shrubs consumed less foliage than goats offered a mixture of two shrubs containing tannins and saponins: Quercus and Hedera (21.6 vs. 27.1 g/kg BW), Arbutus and Hedera (21.8 vs. 27.1 g/kg BW), and Pistacia and Hedera (19.7 vs. 22.0 g/kg BW). Comparison of intake of shrubs containing only tannins or saponins to intake of shrubs containing both tannins and saponins indicated that goats consumed more total biomass when fed with shrubs with both classes of compounds than with either tannins or saponins alone. Our results suggest that goats can increase intake of Mediterranean shrubs high in secondary compounds by selecting those with different classes of phytotoxins. Simultaneous ingestion of shrubs containing tannins and saponins may promote chemical interactions that inhibit toxic effects of these phytotoxins in the intestinal tract. In addition to complementary interactions between tannins and saponins, biological diversity within Mediterranean maquis vegetation also plays a positive role in increasing shrub intake by goats.

}, keywords = {biodiversity, goats, Maquis, Mediterranean shrubs, saponins, secondary compounds, tannins}, doi = {10.1007/s10886-006-9084-1}, url = {/files/bibliography/06-023.pdf}, author = {Rogosic, J. and Richard E. Estell and Skobic, D. and Martinovic, A. and Maraic, S.} } @conference {50508, title = {Restoration of spatial heterogeneity and ecohydrological processes in deserts: Development of artificial islands of hydrologically-enhanced productivity}, booktitle = {American Geophysical Union}, volume = {87}, number = {52}, year = {2006}, month = {December 11-15, }, pages = {H13A-135B}, address = {San Francisco, CA}, abstract = {Temporal and spatial heterogeneity in biological productivity, from the scale of plants to landscapes, is characteristic of arid and semi-arid ecosystems. The processes which control the formation of resource islands and determine the size, shape, longevity and distribution of resource islands across the landscape are influenced by climate, topography, soils and biota. The installation of water retention dikes (7.5-30 cm tall, 50-150 m long) at the Jornada Experimental Range (3-6 dikes/site at 4 sites) in the Chihuahuan Desert from 1975-1981 enabled us to test whether increased surface water retention was sufficient to initiate the formation of islands of enhanced resource availability and biological productivity. Compared to nearby reference areas, soil moisture was 20-45\% higher behind dikes. Clay and silt soil fractions tended to be greater behind the dikes, though the detailed pattern depended upon the local site conditions. Soil aggregate stability was higher and saturated infiltration rates were up to 80\% lower behind the dikes. Vegetation cover behind the dikes was more than twice that in nearby reference areas. Plant species richness was up to 4 times greater behind the dikes. Mesquite (Prosopis spp.) and unpalatable shrubs were less dominant behind the dikes, while cover of small shrubs, grasses and forbs was greater than in reference areas. Rehabilitation of degraded arid ecosystems often entails the restoration of spatial heterogeneity and the creation of islands of concentrated resources. Artificial water retention structures can mimic natural processes that reduce surface water flow rates, allowing more time for infiltration, and can initiate formation of islands of increased resource availability and increased biological productivity. The effects of these water retention dikes persisted for up to 30 years without maintenance.}, keywords = {echohydrological, heterogeneity, hydrologically-enhanced, spatial}, author = {S. Tartowski and Jeffrey E. Herrick and A. Rango} } @article {50515, title = {Rangeland research: strategies for providing sustainability and stewardship to the rangelands of the world}, journal = {Rangelands}, volume = {28}, number = {6}, year = {2006}, month = {December 2006}, pages = {7-14}, abstract = {Rangeland research is an important determinant of how rangelands are and will be used. Although larger external forces such as national and global economies and social and political attitudes have direct impact on uses of rangelands, the methods by which we implement and evaluate those economic and social priorities are based in research and development. Decisions made by rangeland scientists and their institutions today about priorities will have a definite and profound influence on the management of our rangelands in the future. The Society for Range Management, in a once-a-decade symposium, examines the current state of the science, existing technologies and changing social and political trends to identify research needs. In 2005, SRM brought together over 2 dozen speakers and 100 participants to examine new directions in rangeland use and management and propose changes to research that will provide decision-makers at all levels the necessary tools to set goals, implement management and monitor performance.}, keywords = {management, rangelands, sustainability, vegetation}, url = {http://www.srmjournals.org/archive/1551-501X/28/6/pdf/i1551-501X-28-6-7.pdf}, author = {Vavra, J. and Joel R. Brown} } @proceedings {50535, title = {Rangelands and Global Change}, year = {2005}, note = {Global Issue Paper}, month = {July 1, 2005}, pages = {11}, publisher = {Society for Range Management}, address = {Lakewood, CO}, abstract = {GLOBAL CHANGE is any change in the global environment that may alter the capacity of the Earth to sustain life. Included are changes in changes in LAND USE and PRODUCTIVITY, ATMOSPHERIC CHEMISTRY, CLIMATE, WATER RESOURCES and ECOLOGICAL SYSTEMS (U.S. Global Change Research Act 1990). These changes can be attributed primarily to the growth in human population (\>6 billion in 1999) and their use of natural resources. There are two forms of responding to global change: mitigation and adaptation. Mitigation are actions taken to reduce the amount of change that occurs, while adaptation refers to actions that are taken to reduce the impact of change. RANGELANDS are lands on which the indigenous vegetation is predominantly grasses, grass-like plants, forbs or shrubs and is managed as a natural ecosystem and include grasslands, savannas, shrublands, deserts, tundras, marshes and meadows (Forage and Grazing Terminology Committee 1991). In the United States, over one-third (770 million acres) of the land area is classified as rangeland. Over half of rangelands are privately owned. In general, rangelands west of the Rocky Mountains are dominated by federal ownership, while those east of the Rockies are predominately privately-owned. There are notable exceptions, particularly along the west coast, where productivity is high enough to warrant private ownership. The significance of ownership is not in how rangelands should be treated in response to global change, but in the policies and programs that must be crafted and implemented to achieve those treatments. (http://www.rangelands.org/pdf/Global_Issue_Paper.pdf)}, keywords = {atmospheric, change, chemistry, global, issue paper, land use, management, producivity, range, society}, url = {/files/bibliography/05-009.pdf}, author = {Joel R. Brown and Blake, R.R. and McPherson, G.R. and Tate, K.W.} } @conference {50536, title = {Research Needs: Making vegetation dynamics a basis for vegetation management}, booktitle = {Society for Range Mangement 58th Annual Meeting}, year = {2005}, month = {February 5-11, 2}, pages = {194}, address = {Fort Worth, TX}, abstract = {The 1994 SRM Research Needs Symposium identified three important developments for vegetation science in the coming decade: 1) improved understanding of nonequilibrium dynamics, 2) new strategies for halting degradation and 3) sustainable restoration strategies. There has been remarkable progress toward achieving these goals in the last 10 years. However, continued progress in increasing the relevance of vegetation science to land management will require more than just broader application of existing techniques and principles. We suggest that the pursuit of four new objectives is critical. First, applications of nonequilibrium theory must turn from explaining observations to providing realistic predictions. Our understanding is sufficiently well-developed to go beyond retrospective explanations to predictive principles and tools, within the constraints of uncertaintly. Second, the concepts of vegetation resistance and resilience must be applied at multiple scales, both spatially and temporally to provide a context for land management decisions. Plant communities, landscapes and regions vary tremendously in their general rates and magnitudes of change and recovery. Third, rangeland vegetation science must expand to include dynamic soil:plant relationships as a means of improving predictions and providing a basis for extending research to real-world situations. Many sites in arid and semi- arid areas will not recover in management timeframes and effective land management requires principles to differentiate and set priorities. Finally, vegetation scientists must transcend traditional research:application boundaries to integrate vegetation science into policies and programs that guide land management. Regardless of the extent or precision of knowledge, without clear links to decision-making, it is irrelevant.}, keywords = {degradation, dynamics, nonequilibrium, restoration, SRM, strategies, sustainable}, author = {Joel R. Brown and Brandon T Bestelmeyer} } @conference {50555, title = {Research application of ecological sites and their further development}, booktitle = {Society for Range Management, 58th Annual Meeting and Trade Show}, year = {2005}, month = {February 5, 2005}, pages = {Paper No. 162}, address = {Fort Worth, TX}, abstract = {A general science paradigm for rangeland research includes three basic elements: (1) identification of key basic principles of the biophysical world, (2) development of testable explanations (e.g., models) of the biophysical world based on those principles, and (3) experimentally gathered, georeferenced information to expand and apply explanations to management relevant problems at scales that operate in real time. Within this paradigm is the recognition of three key properties of rangelands relevant to current research questions: rangelands (1) exhibit threshold behaviors in response to various drivers, (2) exhibit temporal and spatial variability in these responses, and (3) exhibit these responses within a landscape context. An ecological site basis for field research provides a useful framework for both acknowledging the importance of these principles and adhering to this paradigm. Spatially relevant and ecologically robust site descriptions of a research landscape provide a clear and repeatable basis for evaluating measured responses and a means to extrapolate those responses to similar conditions and landscapes in other areas.}, keywords = {ecological sites, models, rangeland research, research application, site descriptions}, author = {Kris Havstad} } @proceedings {50585, title = {The role of grass tussocks in maintaining soil condition in northeast Australia}, year = {2005}, month = {July 2005}, pages = {71}, publisher = {Wageningen Academic Publishers}, address = {Oxford, England}, abstract = {Soils of the grazing lands of northeastern Australia are inherently nutrient-poor. Heterogeneously distributed plants are important to the conservation of the limited amounts of nutrients, through storage in plant tissues or in soil sinks close to plants. Loss of perennial vegetation through disturbance reduces conservation of these resources, to the detriment of feedback mechanisms, and ultimately causes loss of soil condition. Large areas of north east Australia have been degraded, or threatened by degradation, through combinations of variability in precipitation and heavy grazing. This study examined the inter-related responses of plants, soil microbes and soil nutrients to management-related disturbance.}, keywords = {Australia, grazing, heterogeneously, nutrients, tussocks}, url = {/files/bibliography/05-047Proc.pdf}, author = {Northup, B.K. and Joel R. Brown} } @article {50604, title = {Rangeland Field Data Techniques and Data Applications}, journal = {Journal of Soil and Water Conservation}, volume = {60}, number = {(5)}, year = {2005}, month = {October 31, 2005}, pages = {114A-119A}, abstract = {The National Resource Inventory (NRI) is a national-level inventory of the nation{\textquoteright}s non-federal land. This article summarizes the current status and uses of the NRI for rangelands. Following the analysis of a 1999 pilot study, the new rangeland NRI was implemented on 980 points in 15 states in 2003. In 2004, it was expanded to an additional 2,369 points. Plant cover, production and structure are measured, as well as the aggregate stability of the soil surface. Current land use and invasive species are also included in the database. The data will be combined with future data to generate a report card of the status of the nation{\textquoteright}s rangelands. Some of the data are also being used to assist with the development of ecological site descriptions.}, keywords = {applications, data, NRI, rangelands}, url = {/files/bibliography/05-017.pdf}, author = {K. Spaeth and G. Peacock and Jeffrey E. Herrick and P. L. Shaver and R. Dayton} } @proceedings {50606, title = {Recognition of semi-arid vegetation types based on MISR multi-angular observations and surface anisotropy patterns iinversed by bidirectional reflectance models}, year = {2005}, month = {October 17, 2005}, pages = {186-189}, abstract = {Mapping accurately community type is one of main challenges for monitoring semi-arid grasslands with remote sensing. Multi-angle approach has been proved useful for mapping vegetation types in desert. Multi-angle Imaging Spectro-Radiometer (MISR) provides 4 spectral bands and 9 angular observations. In this paper, several classification experiments were done to find the optimal combination of MISR multi-angular observations to mine the information carried by MISR data as effective as possible. The experiments show the following findings: 1) The combination of MISR 4 spectral bands nadir observation and red and near infrared bands C, B, A camera observations can obtain the best vegetation type differentiation at community level in New Mexico desert. 2) The k parameter at red band of Martonchik-Rahman-Pinty-Verstraete (MRPV) model and the structural scattering index (SSI) can bring additional useful information to land cover classification. 3) The information carried by the two parameters, however, is less than that carried by surface anisotropy patterns described by the MRPV model and a linear semi-empirical kernel-driven bidirectional reflectance distribution function model, RossThick-LiSparse-Reciprocal model. These experiments prove that multi-angular data raises the classification accuracy from 45.4\% of nadir observation to 60.9\%, and with surface anisotropy patterns derived from MRPV and RossThick-LiSparse-Reciprocal accuracy 67.5\% can be obtained when maximum likelihood algorithms are used. Support vector machine algorithms can raise the classification accuracy to 76.7\%. This research suggests that multi-angular observations, surface anisotropy patterns and SVM algorithms can improve semi-arid vegetation type differentiation remarkably.}, keywords = {classification, MISR}, url = {/files/bibliography/05-056Proc.pdf}, author = {L. Su and M. Chopping and A. Rango and J. V. Martonchik and Debra C. Peters} } @article {50607, title = {Replicated host-race formation in bogus yucca moths: genetic and ecological divergence of Prodoxus quinquepunctellus on yucca hosts}, journal = {Evolutionary Ecology Research}, volume = {7}, year = {2005}, note = {//USDA//LTER IV//Entered 1/9/2006}, month = {2005}, pages = {1139-1151}, abstract = {Goal: Assess host-race formation in certain moths by examining their genetic and ecologicaldifferentiation.Organisms: Stalk-feeding moths, Prodoxus quinquepunctellus, collected from sympatricpopulations of Yucca elata and Y. rostrata in west Texas, USA.Results: Moths on the two yuccas differed significantly in mtDNA haplotype frequencies,emergence time, wing dot number, body size, and ovipositor size and shape.Conclusion: Host-race formation has probably occurred in this yucca moth although geneticdivergence was low.}, keywords = {article, diversification, host-race formation, mitochondrial DNA, ovipositor morphology,, journal, phenology, Prodoxidae, Yucca., speciation}, author = {Svennson, Glenn P. and David M. Althoff and Pellmyr, Olle} } @proceedings {50620, title = {Representing spatially explicit Directional Virtual Fencing (DVF-trademark) data}, year = {2004}, month = {August 7-10, 200}, address = {San Diego, CA}, abstract = {

Distributing free-ranging animals across a landscape to facilitate proper vegetation utilization is universally challenging to resource managers. Combining GPS technology, GIS methodology, and animal behavior, we have developed a device that autonomously controls animal distribution without conventional wire fencing or herding. Directional Virtual Fencing (DVF) uses sensory cues administered at the proper time and in the correct location on the animal to keep animals within a Virtual Paddock (VP) that can move in time and space using programmable Virtual Boundaries (VB). Analyzing the resulting geospatial animal data obtained from the device using ArcGIS Tracking Analyst software provides essential information for understanding and subsequently managing animal distribution.

}, keywords = {animal, Directional Virtual Fencing, distribution, GIS, GPS}, url = {http://training.esri.com//files/bibliography/index.cfm?event=general.recorddetail\&id=33833}, author = {D.M. Anderson and B. Nolen and E.L. Fredrickson and Kris Havstad and C.S. Hale and Nayak, P.} } @conference {50633, title = {Region-wide empirical testing of state-and-transition models}, booktitle = {57th Annual Meeting of Society for Range Management}, year = {2004}, month = {January 25-30, 2}, pages = {Abstract No. 31}, address = {Salt Lake City, UT}, abstract = {Conceptual state-and-transition models for southern New Mexico were developed from literature reviews and expert opinion. These models describe patterns and causes of succession and persistent transitions in vegetation for particular ecological sites (groups of soil types), as well as indicators of the mechanisms underlying those dynamics. Propositions in state-and-transition models are difficult to test because vegetation transitions and patterns of resilience are expressed over decades in semiarid environments and because valid tests must be conducted at regional scales. We are using long-term (up to 35 yr) trend-plot photographic records and other sources of repeat photography from throughout southern New Mexico, coupled with detailed soil and landscape characterization to evaluate several predictions arising from state-and-transition models. We report evidence that (1) vegetation on fine-textured and shallow, skeletal soils is comparatively resistant and resilient, while that on fine to coarse loamy soils continues to undergo transitions, (2) transitions may be caused by contagious processes, such as sand deposition from adjacent sites, that depend on landscape context rather than local management, (3) encroaching shrub species that are featured in current state-and-transition models may not be the shrub species that will cause future transitions, and (4) subtle variations in regional climate and soil properties may have a greater impact on the probability of transition than was previously recognized. We discuss the general problem of using localized historical studies to generate region-scale forecasts in rangelands.}, author = {Brandon T Bestelmeyer and Joel R. Brown and Kris Havstad and D. Trujillo} } @conference {50648, title = {The role of heteromyid rodents in establishment and survival of mesquite in Chihuahuan Desert black grama (Bouteloua eriopoda) grasslands}, booktitle = {Sixth Symposium on the Natural Resources of the Chihuahuan Desert Region}, year = {2004}, month = {October 15, 2004}, pages = {21}, address = {Alpine, TX}, abstract = {We conducted experiments to examine the relative influence of fire, small mammal activity, and microsite location on the germination and survival of honey mesquite (Prosopis glandulosa) in Chihuahuan Desert black grama (Bouteloua eriopoda) grassland. Mesquite seeds were placed in simulated heteromyid rodent cache pits in unburned and burned black grama grassland and on banner-tailed kangaroo rat (Dipodomys spectabilis) burrow mounds. Germination was highest in the unburned grassland, but over-winter survival was greater in the burn microsites. A large proportion seed pits were partially excavated (between 15.6 to 21.1\% of the uncaged pits and between 1.1 to 5.5\% of the caged pits). However, between 0 to 50.0\% of the seedlings germinated in pits that had previously been excavated. Of the seeds placed in the field in the early monsoon season, 8.0\% survived over winter and 13.6\% of the germinants from the post-monsoon season survived over winter. There was higher germination (13.8\%) from the early monsoon experiment than in the post-monsoon experiment (3.9\%). There were seasonal differences in numbers of emergent seedlings with a peak in September 2002 following late summer rains. There were no significant differences in numbers of germinants in burn and grass microsites, but there were significantly fewer germinants on banner-tailed kangaroo rat mounds. These studies suggest that heteromyid rodents may serve as agents of dispersal for honey mesquite in Chihuahuan Desert black grama grasslands.}, keywords = {agents of dispersal, black grama, Chihuahuan Desert, fire, heteromyid rodents, mesquite, microsite location, small mammal activity}, author = {B.D. Duval and Aaron Killgore and E. Jackson and Walter G. Whitford} } @article {50671, title = {Resistance to overland flow due to bed-load transport on plane mobile beds}, journal = {Earth Surface Processes and Landforms}, volume = {29}, year = {2004}, note = {//NONE//LTER IV//}, month = {2004}, pages = {1691-1701}, abstract = {

During bed-load transport by overland flow, momentum is transferred from the flow to the bed via grain collisions, resulting in a decrease in flow velocity and an increase in flow resistance, herein termed bed-load transport resistance. In overland flow on mobile plane beds, total flow restistance f consists of grain resistance fg and bed-load transport resistance fbt. In order to identify and evaluate the relative importance of the factors controlling fbt, 38 flume experiments were performed on slopes of 2.7 and 5.5{\textordmasculine} using sediment with median diameters of 0.74 and 1.16 mm. All flows were supercritical and turbulent. This study is an extension of a recent study by Gao and Abrahams (Earth Surface Processes and Landforms 2004, vol. 29, pp. 423-435). These authors found that fbt is controlled by three factors: sediment concentration C, dimensionless sediment diameter D*, and relative submergence h/D, where h is flow depth, D is median sediment diameter. However, a new dimensional analysis identifies two additional factors: Froude number F and slope S. Multiple regression analyses reveal (1) that these five factors together explain 97 per cent of the variance of fbt, and (2) that S control fbt entirely through C. The variable C is therefore redundant, and a new functional equation relating fbtto D*, h/D, S and F is developed. This equation may be used to predict fbt. An advantage of this equation is that it may be used to predict fbt without measuring bed-load transport rate. Copyright {\textcopyright} 2004 John Wiley \& Sons, Ltd.

}, keywords = {hydrology, bedload, hydrology, flow resistance, hydrology, hillslopes, hydrology, overland flow, hydrology, overland-flow hydraulics, hydrology, processes}, doi = {10.1002/esp.1123}, url = {files/bibliography/JRN00416.pdf}, author = {Hu, Shixiong and Athol D. Abrahams} } @conference {50690, title = {Rangeland monitoring and prediction at range to regional scales}, booktitle = {57th Annual Meeting, Society for Range Management }, year = {2004}, month = {January 25, 2004}, pages = {267}, address = {Salt Lake City, UT}, abstract = {The USFS, BLM and NRCS have responsibility to inventory and monitor rangelands in connection with their land use planning and management duties. Despite these efforts, a recent National Research Council study concluded that rangeland monitoring is inconsistent, inadequate, infrequent and does {\textquoteright}not provide the data needed to support national assessments of rangeland health.{\textquoteright} In preliminary studies, ARS scientists have shown that a combination of ground-based inventory with ARS models and available satellite images provides accurate and consistent information. To assimilate these three methods - conventional ground-based inventory, remote sensing and simulation modeling {\textquoteright} a multi-stage research thrust is necessary. First steps would be to refine current inventory and modeling approaches to accept image data and to improve extraction of range-specific information from satellite images. Second, an error assessment mechanism should be developed to determine information accuracy for any combination of the three methods. Third, all 1-, 2- and 3-method combinations should be tested for monitoring and predicting rangeland information at ARS experimental watersheds and rangelands in key locations in the U.S. Finally, a decision tool should be developed to assist users in selecting the most appropriate approach for their location. At all stages, an adaptive research approach must be used to improve all methods in response to error assessment and user feedback. The ultimate goal of this initiative would be to develop the best possible methods for rangeland monitoring and prediction. This synergistic approach will produce better information for a variety of rangeland types than could be obtained by any one method alone.}, author = {S. Moran and Thoma, D. and Mariano Hernandez and Phil Heilman and Stone, J.J. and Paul F. Starrs and Arnold, J.G. and J.R. Kiniry and Richardson, C.W. and A. Rango and Jeffrey E. Herrick and Debra C. Peters and Kris Havstad} } @article {50698, title = {Regeneration of black grama (Bouteloua eriopoda Torr. Torr) plants via somatic embryogenesis}, journal = {In Vitro Cellular and Developmental Biology - Plant}, volume = {40}, year = {2004}, month = {May 1, 2004}, pages = {299-302}, abstract = {Seeds of Bouteloua eropida, (Torr.) Torr. were surface disinfested and germinated on a carbon mineral rich medium. Callus was initiated from embryonic shoots excised from the roots on auxin supplemented medium. After callus multiplication, embryos were induced from callus. They developed into normal embryos and caryopses that subsequently developed into intact plants. Regenerated plants were transplanted into soil and grown in the growth chamber. The utilization of regenerated plants for plant-fungus associations is discussed.}, keywords = {black grama, Bouteloua eriopoda, regeneration, somatic embryogenesis}, url = {/files/bibliography/04-009.pdf}, author = {P. Osuna and J.R. Barrow} } @conference {50697, title = {Regeneration of black grama (Bouteloua eriopoda Torr. Torr) plants via somatic embryogenesis and the internal colonization of endophytic fungi}, booktitle = {2004 World Congress on In Vitro Biology}, year = {2004}, month = {May 2004}, address = {San Francisco, CA}, abstract = {Black grama (Bouteloua eriopoda) is an important forage grass in southwestern USA rangelands. Plants were regenerated by somatic embryogenesis. Surface disinfested seeds were germinated and the embryonic shoots were excised and cultured on Murashige and Skoog (MS) medium gelled with agar. Callus was induced from apical meristems. Calluses were cultured on MS solid medium with six concentrations of 2,4, D (2,4-dichlorophenoxyacetic acid) or Dicamba (6-dichloro-o-anisic acid) for 6 weeks under light or dark conditions. Somatic embryo induction was greatest on 4.52 um Dicamba, under light, after transferring to an auxin- free medium. Embryo development progressed from globular, torpedo to mature embryos phenotypically identical to those naturally produced in seed that developed into intact plants and were established in soil and grown to maturity. Two fungal species, Aspergillus ustus and Puccinia cacabata consistently associated with native populations were also found to be intimately integrated with meristematic mother cells from germinating seedlings and were associated with cells, tissues and regenerated plants. Fungi form protective biofilms on cells and tissues in culture and on root and leaf surfaces of regenerated and native plants. The ecological role of these endophytes is to protect plant surfaces from hostile external environmental conditions.}, keywords = {black grama}, author = {P. Osuna and J.R. Barrow} } @conference {50710, title = {Repetitive remote sensing over southwestern US rangeland undergoing vegetation change, JORNEX 1995-2004}, booktitle = {2004 Western Pacific Geophysics Meeting}, series = {Eos Transactions, American Geophysical Union Supplement}, volume = {85(28)}, year = {2004}, month = {August 16, 2004}, pages = {Abstract No. H22A-03}, address = {Honolulu, Hawaii}, abstract = {Evaporation from soil surfaces is a major component of the surface water and energy budgets. The potential ability of estimating soil evaporation with remote sensing measurements has great significance in modeling land surface processes and assessing potential environmental stresses in natural ecosystems. The objective of this study was to explore possible algorithms of applying hyper-spectral and multi-temporal reflectance measurements for evaporation estimation. A 16-band hyper-spectral radiometer was used for the reflectance measurements during two-stage evaporation. The radiometer covered a band range of 400 to 1720 nm with band widths ranged from 7 to 13 nm. An infrared thermometer was also used for temperature measurement. To create simultaneous measurements of soil reflectance and the rate of evaporation, a large steel frame or balance was fabricated which contained a 0.5-m wide by 0.5-m long by 0.07-m deep soil tray placed directly on top of an electronic balance. The radiometer was mounted at a height of 0.5 to 1.0 -m above the tray during each measurement. The balance frame was needed to counter the excess or stationary weight from the tray and dry soils in the tray, yet sensitive enough to detect 0.01-g change of the tray. Micro-meteorological variables, including air temperature at different heights from the tray, solar radiation and net radiation, wind speed, and relative humidity, were also measured at the same time in order for an independent evaporation estimation. During each measurement, the tray was filled with one type of soil, saturated with water, then started the reflectance and weight-change measurements while evaporation was occurring. The experiments were carried out in clear, calm, sunny days, and repeated for different soil types. Each experimental run was maintained until at least 1-hr after the transition from atmosphere-limited to soil-limited evaporation (or the two-stage soil evaporation). To determine the most useful band combination, a spectral dependent soil line, instead of the traditional soil lines, was created based on the band index and maximum changes of soil surface spectral properties associated with water content decrease during evaporation. A spectral simple ratio was formulated, and in combination with the surface temperature measurement, to calculate the actual evaporation rate. The preliminary results served as a proof of concept, and it appeared to be promising. The simple statistical fit could be useful for other situations as well. However, more testing or validation is needed before using the technique in actual field applications with aircraft or satellite images.}, keywords = {JORNEX, remote sensing, repetitive, southwestern US, vegetation change}, author = {A. Rango and Jerry Ritchie and T. J. Schmugge and William P. Kustas and Kris Havstad and M. Chopping and Andrea S. Laliberte and Caitriana Steele} } @conference {50715, title = {The role of animals in desertification: Herbivory patterns in degraded grassland}, booktitle = {89th Annual Meeting, Ecological Society of America}, year = {2004}, month = {August 1, 2004}, pages = {Abstract p. 438}, address = {Portland, OR}, abstract = {We examined the contribution herbivores make to the resistance and resilience of desert grassland ecosystems following a desertification process. The study took place in the Jornada Experimental Range, New Mexico, where, historically, desert grassland has gone through the desertification process during the past century. We monitored browsing signs on snakeweed (Gutierrezia sarothrae), the dominant sub-shrub in the landscape, and on all perennial grass species. Snakeweed was monitored for browsing on a monthly basis over a period of a year, while grasses were evaluated for herbivory in a single assessment at the end of their growing season. Plots grazed by livestock for 3 subsequent years were compared with undisturbed ones. Domestic animals grazing ceased in 1998, hence all herbivory documented is related to wild rabbits and rodents. Results show clear spatial and temporal herbivory patterns on snakeweed. The animals browsed in patchy patterns and have shown significant tendency for repeated browsing on specific plants, which indicates a nonrandom feeding behavior. Relatively high browsing frequency and biomass intake were documented between November and March, which forms the dry season in the northern Chihuahuan Desert. A significant decrease in snakeweed browsing was detected with the appearance of annuals and ceased almost completelywith the availability of perennial grasses. Despite the temporal pattern detected, plant-water content failed to explain the herbivore spatial feeding preferences. Grasses had much lower initial abundance and biomass compared to snakeweed. This resulted in a significantly higher relative percentage of grass biomass consumed by herbivory. That effect strongly intensified in formerly grazed plots where initial grass cover was the lowest. By the end of their growing season almost no grass flowering tillers survived which caused insufficient seed reservoir. Our findings show that herbivores contribute to the resistance and resilience of degraded grasslands by reducing the reestablishment of grasses.}, keywords = {desert grassland ecosystems, desertification, herbivory patterns, role of animals}, author = {Roth, G.A. and Walter G. Whitford and Yosef Steinberger} } @proceedings {50767, title = {Rangeland research on the Jornada Experimental Range}, year = {2003}, month = {March 27-28, 200}, pages = {87-91}, address = {Farmington, NM}, abstract = {The mission of the Jornada Experimental Range is to develop new technologies for the management and remediation of desert rangelands. A few studies in progress that relate directly to this mission are summarized below. One major focus is to develop methodologies for controlling livestock distribution on rangelands. A study is in progress to evaluate the potential of virtual fencing as an alternative to conventional fencing for real-time control of animal movement. A small solar-powered unit worn by the animal uses signals from GPS satellites to determine animal location and a GIS database to define a virtual boundary. When an animal penetrates this boundary, a cue is applied to encourage the animal to move away from the virtual boundary. Preliminary data indicate this low-stress technology can be used to control animal movement. Protein supplementation during conditions of low quality forage is another practice that may be used to control animal movement. Preliminary data indicate that protein supplementation affects beef cow distribution patterns with non-supplemented animals exhibiting greater dispersal and supplemented cows remaining near supplementation areas. These studies have implications for improving forage utilization and livestock management, as well as excluding livestock from ecologically sensitive areas. A third study in progress involves quantification of carbon storage in plants and soils on arid rangelands. This research combines direct field measurement of CO2 fluxes, soil carbon analysis, and modeling. The project will examine how carbon storage might change naturally over time or be influenced by management practices. Initial results suggest rangelands may serve as a significant long-term repository for carbon when shrubs store large amounts of carbon belowground in their extensive woody root systems. Also, aerial photography is being examined as a tool to reconstruct the remediation treatment history of rangelands. Many treatments have been implemented during the last 100 years in an effort to slow shrub invasion, but over time, land management agencies have been disbanded or reorganized and paper records have been lost, resulting in poor documentation of type and extent of treatment, methods used, and evaluations of success. Nationwide aerial photography begun by USDA and other agencies as early as 1930 is a valuable source of information for establishing past management histories and vegetation response to treatments on rangelands. Treatments imposed on the Jornada during early research projects (e.g., root plowing during the 1970{\textquoteright}s, ponding dikes constructed in 1975, and manual shrub removal in 1936) are still evident in aerial photographs today. Combining aerial photography and remaining conventional records with present day field measurements greatly increases the total information available regarding the management history and most effective remediation approaches for use today.}, keywords = {cattle growers, course, livestock, rangeland, research, research notes}, url = {/files/bibliography/03-003.pdf}, author = {Richard E. Estell and D.M. Anderson and E.L. Fredrickson and Kris Havstad and K. A. Mitchell and A. Rango} } @article {50792, title = {Remote sensing research in hydrometeorology}, journal = {Photogrammetric Engineering and Remote Sensing}, volume = {69}, year = {2003}, month = {2003}, pages = {631-646}, abstract = {

\  An overview of remote sensing research in hydrometeorology, with an emphasis on the major contributions that have been made by United States Department of Agriculture- Agricultural Research Service (USDA-ARS) scientists, is provided. The major contributions are separated into deriving from remote sensing (1) hydrometeorological state variables and (2) energy fluxes, particularly evapotranspiration which includes plant water stress. For the state variables, remote sensing algorithms have been developed for estimating land surface temperatures from brightness temperature observations correcting for atmospheric and emissivity effects, estimating near-surface soil moisture from passive microwave remote sensing, determining snow cover from visible and snow water equivalent from microwave data, and estimating landscape roughness, topography, vegetation height, and fractional cover from lidar distancing technology. For the hydrometeorological fluxes, including plant water stress, models estimating evapotranspiration have been developed using land surface temperature as a key boundary condition with recent schemes designed to more reliably handle partial vegetation cover conditions. These research efforts in estimating evapotranspiration with remotely sensed surface temperatures have been utilized by ARS researchers in the development of the Crop Water Stress Index and Water Deficit Index for assessing plant water stress. In addition, the development of the Thermal Kinetic Window and Crop Specific Temperatures have revealed the dynamic interactions among foliage temperature, plant species, and the physical environment. ARS researchers continue to develop new and improved remote sensing algorithms for evaluating state variables and fluxes. Moreover, they are involved in new research directions to address science questions impeding hydrometeorological research. These include investigating the utility of combining multifrequency remote sensing data for improved estimation of land surface properties, and incorporating remote sensing for evaluating the effects of landscape heterogeneity on atmospheric dynamics and mean air properties and resulting feedbacks on the land surface fluxes.

}, keywords = {hydrometeorology, remote sensing}, doi = {10.14358/PERS.69.6.631}, url = {/files/bibliography/03-023.pdf}, author = {William P. Kustas and A.N. French and J. Hatfield and T. J. Jackson and S. Moran and A. Rango and Jerry Ritchie and T. J. Schmugge} } @article {50795, title = {Relationship between the aerodynamic roughness length and the roughness density for low roughness density}, journal = {Environmental Fluid Mechanics}, volume = {3}, year = {2003}, note = {//NONE//LTER IV//Added 07/29/2005, Updated 05/16/2006}, month = {2003}, pages = {249-267}, abstract = {

This paper presents measurements of roughness length performed in a wind tunnel for low roughness density. The experiments were performed with both compact and porous obstacles (clusters), in order to simulate the behavior of sparsely vegetated surfaces. The experimental results have been used to investigate the relationship between the ratio z/h and the roughness density, and the influence of an obstacle{\textquoteright}s porosity on this relationship. The experiments performed for four configurations of compact obstacles provide measurements of roughness length z for roughness densities {\"e} between 10-3 and 10-2 which are in good agreement with the only data set available until now for this range of low roughness densities. The results obtained with artificial porous obstacles suggests that the aerodynamic behavior of such roughness elements can be represented by the relationship established for compact obstacles, provided a porosity index has been used to determine the efficient roughness density (the fraction of the silhouette area actually sheltered by solid elements) rather than counting the porous object as solid. However, the experiments have been performed with relatively low porosity indices (maximum =25\%) for which the porosity has a negligible influence. In this range of porosity index, representing the aerodynamic behavior of porous obstacles using the relationship established for compact obstacles, should not lead to a significant error. However, the influence of the porosity may be important for porosity indices larger than 30\%.

}, keywords = {aeolian transport, article, eolian processes, vegetated surfaces, journal, roughness, wind tunnel}, doi = {10.1023/A:1022830119554 }, url = {files/bibliography/JRN00393.pdf}, author = {Minivielle, F. and Marticorena, G. and D. E. Gillette and Robert E. Lawson Jr. and Roger S. Thompson and Gilles Bergametti} } @article {50803, title = {The role of overland flow in sediment and nitrogen budgets of mesquite dunefields, southern New Mexico}, journal = {Journal of Arid Environments}, volume = {53}, year = {2003}, note = {//USDA//LTER IV//}, month = {2003}, pages = {61-71}, abstract = {

Rainfall-simulation experiments were conducted within the Jornada Experimental Range, southern New Mexico, on small plots located on mesquite nabkha and interdune spaces. Data from these experiments were used to determine runoff, sediment and nitrogen losses, and to measure the effect of soil crusts in interdune spaces on these quantities. Results show that runoff from the nabkha plots amounted to only 7.8\% of the applied rainfall, whereas from the interdune plots it was 75.7\%, rising to 90.8\% from plots where the soil crust was protected from raindrop impact. Sediment yield from the nabkha plots averaged 0.24g m-2s-1 and from the interdune plots it averaged 0.70 g m-2 s-1, with no difference between the protected and unprotected plots. Nitrogen losses in runoff averaged 1.45 mg l-1 from the nabkha plots and 0.61 mg l-1 from the interdune plots. However, because of the much greater runoff from the interdune areas total nitrogen loss from interdune plots was three times that from the nabkha plots. Rates of annual sediment loss by runoff are estimated to be similar to rates of aeolian erosion, but rates of dissolved nitrogen loss are estimated at only between 2\% and 7\% of total atmospheric deposition and less than 1\% of nitrogen fixation by mesquite. {\textcopyright}2002 Elsevier Science Ltd.

}, keywords = {article, articles, journal, journals, mesquite dunes, nitrogen budget, mesquite dunes, runoff, mesquite dunes, sediment budget, mesquite nabkha, runoff, runoff, nitrogen budget, runoff, sediment budget}, doi = {10.1006/jare.2002.1021}, url = {files/bibliography/JRN00400.pdf}, author = {A.J. Parsons and John Wainwright and W. H. Schlesinger and Athol D. Abrahams} } @article {50808, title = {Rime and graupel: Description and characterization as revealed by low temperature scanning electron microscopy}, journal = {Scanning}, volume = {25}, number = {3}, year = {2003}, month = {May 1, 2003}, pages = {121-131}, abstract = {

For nearly 100 years, investigators using light microscopy have vaguely alluded to unique types of snow crystals known as rime and graupel. However, the limited resolution and depth of field of the light microscope have prevented investigators from characterizing these crystals. In this study, a field emission scanning electron microscope equipped with a cold stage was used to document the structural features, physical associations and atmospheric metamorphosis of rime and graupel snow crystals. Rime and graupel form in clouds having both snow crystals and super cooled cloud droplets. This study shows that the frozen droplets range from 10-50um in diameter. With the low temperature scanning electron microscopy approach, it is possible to distinguish the original snow crystal types until the accretion of droplets become thick enough to obscure the original crystal and graupel is the result. With continued riming, lump graupel can reach a diameter of 1-3mm. This study confirms the light microscopy conclusion that the structure of graupel includes considerable air spaces. The low temperature electron microscope approach is the only method that allows measurement of the accreted cloud droplets on rimed crystals and graupel.

}, doi = {10.1002/sca.4950250304}, url = {/files/bibliography/03-025.pdf}, author = {A. Rango and J. Foster and E. G. Josberger and E. R. Erbe and C.D. Pooley and W.P. Wergin} } @proceedings {50815, title = {Remote sensing in watershed scale hydrology}, year = {2003}, note = {//USDA//LTER IV// Listed in LTER IV 2004 annual reportProCite field[6]: In}, month = {2003}, pages = {580-585}, abstract = {

Remote sensing provides a means of observinghydrological state variables over large areas. The ones which we will consider is this paper are: land surface temperature from thermal infrared data, surface soil moisture from passive microwave data, snow cover and water equivalent using both visible and microwave data, water quality using visible and near infrared data, landscape cover using both
visible and near infrared data and landscape surface roughness using lidar.

}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, hydrology, remote sensing, hydrology, watershed scale, proceeding, proceedings, remote sensing, hydrology, remote sensing, watershed scale hydrology}, url = {files/bibliography/Rango2003-02.pdf}, author = {Rawls, W. and William P. Kustas and T. J. Schmugge and Jerry Ritchie and T. J. Jackson and A. Rango and Doraiswamy, P.} } @proceedings {50821, title = {Recognizing history in range ecology: 100 years of science and management on the Santa Rita Experimental Range}, year = {2003}, month = {October 30-Novem}, pages = {1-15}, publisher = {U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station}, address = {Tucson, AZ}, abstract = {At the centennial of the Santa Rita Experimental Range, historical analysis is called for on two levels. First, as a major site in the history of range ecology, the Santa Rita illuminates past successes and failures in science and management and the ways in which larger social, economic, and political factors have shaped scientific research. Second, with the turn away from equilibrium-based models in range sciencea turn prompted in part by research at the Santa Ritathere is a growing need for history in range ecology itself. I discuss the needs, premises, and events underlying establishment of the Santa Rita in 1903. Then I examine the evolution of research and management recommendations through four major periods from 1901 to 1988, and I discuss the land swap that transferred the Santa Rita to State ownership in 1988 to 1991. Finally, I consider what effects the Santa Rita has had on rangelands and range management in the region. I argue that a static conception of the carrying capacity of Southwestern rangelands was imposed for economic and political reasons, over the objections or reservations of early range scientists at the Santa Rita, and that this may have contributed both to range depletion and to rancorous relations between public agencies and private ranchers in the twentieth century. To meet society{\textquoteright}s current demands on rangelands, the long-term, large-scale data assembled from the Santa Rita will be critically important.}, keywords = {carrying capacity, Frederic Clements, history, mesquite, range ecology, range science, semiarid rangelands}, url = {http://www.fs.fed.us/rm/pubs/rmrs_p030.pdf}, author = {N. F. Sayre} } @article {50824, title = {Remote sensing in hydrology}, journal = {Advances in Water Resources}, volume = {25}, year = {2003}, note = {Entered by Beltsville Area}, month = {2003}, pages = {1367-1385}, abstract = {

Remote sensing provides a means of observing hydrological state variables over large areas. The ones which we will consider in this paper are land surface temperature from thermal infrared data, surface soil moisture from passive microwave data, snow cover using both visible and microwave data, water quality using visible and near-infrared data and estimating landscape surface roughness using lidar. Methods for estimating the hydrometeorlogical fluxes, evapotranspiration and snowmelt runoff, using these state variables are also described.

}, keywords = {hydrology, remote sensing}, doi = {10.1016/S0309-1708(02)00065-9 }, url = {/files/bibliography/03-022.pdf}, author = {T. J. Schmugge and William P. Kustas and Jerry Ritchie and T. J. Jackson and A. Rango} } @conference {50879, title = {Remediating degraded ecosystems: Complications of scale}, booktitle = {17th Annual Symposium, US-International Association for Landscape Ecology}, year = {2002}, month = {April 23-26, 200}, pages = {89}, address = {Lincoln, NE}, abstract = {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. An example of these phenomena is the scaled response to livestock overgrazing of and rangelands in the Southwest USA. Initial (late 19th century) overgrazing impacts were at relatively small spatial scales around points of livestock and affected only smaller scale plant community processes. Eventually, the impacts of these disturbances expanded and resulted in larger-scale degradation. By the beginning of the 20th century, the extent was regional as overgrazing, compounded by periodic drought, affected larger-scale processes such as plant dispersal, fire regimes and annual productivity. In addition, changes in regional climatic patterns, continued livestock grazing and introduction of nonnative forage species complicated remediation efforts. Areas where degradation has been remedied are generally small in scale 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. Landscape remediation will require either extensive small-scale practice application and/or improved understanding of landscape dynamics that will trigger large-scale processes.}, author = {Kris Havstad and Joel R. Brown} } @conference {50904, title = {Rapid profiling of shrub volatiles using solid-phase microextraction (SPME) and gas chromatography with mass spectroscopy (GC-MS)}, booktitle = {12th Wildland Shrub Symposium}, year = {2002}, month = {August 12-16, 20}, pages = {27}, address = {Laramie, WY}, abstract = {Shrub volatiles play a significant role in the chemical ecology of desert rangelands. Activities attributed to these compounds include pollinator attraction, herbivore repulsion, allelopathy, pathogen inhibition, and microclimate modification. Since the mid 1980{\textquestiondown}s, advances in laboratory instrumentation and computer software have dramatically reduced the capital and labor costs of sample processing and chemical analyses, expanding the capabilities of small laboratories. Mass spectral databases now include many natural products, and commercialization of Solid Phase Microextraction (SPME) by Supelco Corporation has made routine preparation of thousands of samples feasible for one technician. Here we describe ways we are using SPME, gas chromatography (GC-FID), GC-MS, and mass spectral libraries to rapidly profile, identify, and quantify individual volatiles released by shrubs. Completed profiles include volatile compositions of Ceratoides, Flourensia, Psorothamnus, Dalea, and Gutierrezia, with additional species currently under examination. These profiles can all be obtained by field sampling less than a gram of plant material. The low biomass requirement for sample preparation enables tissue specific sampling with many replicates. Samples are currently cooled under dry ice and transported to the laboratory for SPME followed by GC-MS and GC-FID analyses. Optimization of methods for on-site SPME and gas chromatography is currently underway and will be useful for routine monitoring of shrub volatiles.}, author = {M.E. Lucero and Richard E. Estell and Yi Wang} } @article {50917, title = {Regional analysis of litter quality in the central grassland region of North America}, journal = {Journal of Vegetation Science}, volume = {13}, year = {2002}, note = {//USDA//NONE//}, month = {2002}, pages = {395-402}, abstract = {The central grassland region of North America is characterized by large gradients of temperature and precipitation. These climatic variables are important determinants of the distribution of plant species, and strongly influence plant morphology and tissue chemistry. We analyzed regional patterns of plant litter quality as they vary with climate in grassland ecosystems throughout central North America including tall-grass prairie, mixed grass prairie, shortgrass steppe, and hot desert grasslands. An extensive database from the International Biological Program and the Long-Term Ecological Research Program allowed us to isolate the effects of climate from those of plant functional types on litter quality. Our analysis of grass species confirms a previously recognized positive correlation between C/N ratios and precipitation. Precipitation exhibited a similar positive relationship with lignin/N and percent lignin. Although there was no significant correlation between temperature and C/N, there was a significant positive relationship between temperature and both percent lignin and lignin/N. Among functional types, C3 grasses had a slightly lower C/N ratio than C4 grasses. Tall grass species exhibited higher C/N, lignin/N, and percent lignin than short grass species. This understanding of the regional patterns of litter quality and the factors controlling them provides us with a greater knowledge of the effect that global change and the accompanying feedbacks may have on ecosystem processes.}, keywords = {article, articles, C3, litter quality, C4, litter quality, grassland, dynamics, grassland, precipitation, journal, journals, lignin, litter, litter, C, litter, lignin, N ratio, precipitation, ecosystem dynamics, precipitation, effects on vegetation, precipitation, grassland}, author = {Murphy, Kenneth L. and Ingrid C. Burke and Vinton, Mary Ann and W. K. Lauenroth and M. Aguiar and D. Wedin and R. A. Virginia and Lowe, Petra N.} } @article {50925, title = {Recruitment potential of two perennial grasses with different growth forms at a semiarid-arid transition zone}, journal = {American Journal of Botany}, volume = {89}, number = {10}, year = {2002}, month = {October 1, 2002}, pages = {1616-1623}, abstract = {

The objective of this study was to quantify differences in recruitment potential (seed production, seed presence in the soil) for two congeneric perennial grasses (Bouteloua gracilis, Bouteloua eriopoda [Poaceae]) that dominate adjacent arid and semiarid grassland biomes. It was hypothesized that these species have different recruitment strategies at the biome transition zone that are related to differences in their growth form and longevity. Recruitment potential for each Bouteloua species was compared in patches dominated by one or both species or codominated by the invasive shrub, Larrea tridentata (Zygophyllaceae). Regional variation in recruitment was examined for B. gracilis for cases in which comparable data were available in the literature for a site located within the semiarid grassland biome. The short-lived stoloniferous species B. eriopoda produced more seeds per plant than the long-lived bunchgrass B. gracilis, yet seed viability (\<60\%) and presence in the soil were lower. Mean viability of B. gracilis was higher (\>90\%) than that of B. eriopoda, and a greater percentage of seeds produced on a square meter basis was found in the soil (10{\textendash}25\%). Similar patterns were found for both species in all grass-dominated patches. Bouteloua eriopoda plants growing in patches codominated by L. tridentata produced fewer seeds per plant with lower viability, and fewer seeds were found in the soil compared to grass-dominated patches. Regional comparisons found greater seed production per square meter and more seeds in the soil for B. gracilis at the transitional site compared with a cooler, wetter site located within the semiarid grassland biome. These differences in recruitment potential along with published differences in rates of seedling establishment and vegetative spread may explain, at least in part, localized patterns in species dominance.

}, keywords = {Bouteloua eriopoda, Bouteloua gracilis, Chihuahuan Desert grasslands, grass{\textendash}shrub interactions, intra- and interspecific interactions, Poaceae, seed production, shortgrass steppe}, doi = {10.3732/ajb.89.10.1616}, url = {files/bibliography/JRN00364.pdf}, author = {Debra C. Peters} } @article {50929, title = {Rangeland health attributes and indicators for qualitative assessment}, journal = {Journal of Range Management}, volume = {55}, number = {6}, year = {2002}, month = {November 1, 2002}, pages = {584-597}, abstract = {Panels of experts from the Society for Range Management and the National Research Council proposed that status of rangeland ecosystems could be ascertained by evaluating an ecological site{\textquestiondown}s potential to conserve soil resources and by a series of indicators for ecosystem processes and site stability. Using these recommendations as a starting point, we developed a rapid, qualitative method for assessing a moment-in-time status of rangelands. Evaluators rate 17 indicators to assess 3 ecosystem attributes (soil and site stability, hydrologic function, and biotic integrity) for a given location. Indicators include rills, water flow patterns, pedestals and terracettes, bare ground, gullies, wind scour and depositional areas, litter movement, soil resistance to erosion, soil surface loss or degradation, plant composition relative to infiltration, soil compaction, plant functional/structural groups, plant mortality, litter amount, annual production, invasive plants, and reproductive capability. In this paper, we detail the development and evolution of the technique and introduce a modified ecological reference worksheet that documents the expected presence and amount of each indicator on the ecological site. In addition, we review the intended applications for this technique and clarify the differences between assessment and monitoring that lead us to recommend this technique be used for moment-in-time assessments and not be used for temporal monitoring of rangeland status. Lastly, we propose a mechanism for adapting and modifying this technique to reflect improvements in understanding of ecosystem processes. We support the need for quantitative measures for monitoring rangeland health and propose some measures that we believe may address some of the 17 indicators.}, url = {http://jrm.library.arizona.edu/jrm/GetFileServlet?file=file:///data1/pdf/TheJournalOfRangeManagement/Volume55/Number6/azu_jrm_v55_n6_584_597_m.pdf\&type=application/pdf}, author = {D.A. Pyke and Jeffrey E. Herrick and P. L. Shaver and M. Pellant} } @conference {50930, title = {Reconsideration of using water ponding dikes to reestablish native grasses in srub-invaded areas of the Southwest}, booktitle = {American Geophysical Union, Chapman Conference}, year = {2002}, month = {September 9-13, }, pages = {33}, address = {Taos, NM}, abstract = {Many rangeland treatments have been tested to cause a reversal in the process of shrub invasion into desert grasslands. It seems that, because of the harsh nature of the arid environment, just removing shrubs and even subsequent seeding with native or introduced grasses is not enough to reverse the trend. Several examples are illustrated with historic aerial photography. A more integrated approach seems to be necessary and particularly one that involves concentrating water to increase localized soil moisture. Increased soil moisture alone is not always enough as is evidenced by historic treatments where brush water spreaders and contour terraces were used, although the results of these treatments may have been different if the original treatments had been properly maintained. The relatively simple construction of water ponding dikes seems to produce the best result, and the success and persistence of the dikes appears to vary with soil type. Inexpensive to construct, these dikes require little maintenance but have produced significant results over a period of years. The vegetation response of the Jornada dikes is easily seen using air photos, and the vegetation pattern produced is very similar to naturally occurring "banded vegetation." Grass response has been positive in all water-ponding dike installations, and it appears that native species in the local seedbank respond better than introduced species. Well planned installation of these simple structures over a landscape unit may initiate changes that could lead to reestablishment of grass in the desert ecosystem. Study of banded vegetation systems may generate guidelines for dike spacing on soils with similar hydrologic properties. A series of research water ponding dikes will be established in New Mexico and Arizona to test this treatment over larger areas of the Southwest.}, author = {A. Rango and Jeffrey E. Herrick and Gibbens, Robert P. and S. Moran} } @article {50934, title = {Remote sensing documentation of historic rangeland remediation treatments in southern New Mexico}, journal = {Journal of Arid Environments}, volume = {50}, number = {4}, year = {2002}, note = {Entered in ARIS at Beltsville July 7, 2001}, month = {April 1, 2002}, pages = {549-572}, abstract = {

The Jornada Experimental Range and the New Mexico State University Chihuahuan Desert Rangeland Research Center are fruitful areas to study the long term effects of rangeland remediation treatments which started in the 1930s. A number of diverse manipulations were completed under the direction of federal agency and university scientist, and abundant remote sensing imagery is available to assist in relocating the treatments and evaluating their success. This is particularly important because few of the treatments were maintained following the loss of scientific personnel coinciding with the start of World War II, and most records of Civilian Conservation Corps scientific work were lost with the disbanding of the agency in 1942. Aerial photography, which was systematically used to image the United States beginning in the 1930s, can be used to identify types of treatments, measure area coverage, estimate longevity, and help contour terraces, brush hwater spreaders, strips grubbed free of shrubs (despite the fact that thes strips have remained visible for 65 years), and mechanical rootplowing and seeding. Distinct positive, long-term vegetation responses could be seen in aerial photos and existing conventional records that experimental manipulation of rangelands has often been ineffective on the landscape scale because treatments are not performed over large enough contiguous area and hydrological and ecological processes overwhelm the treatments. In addition, treatments are not maintained over time, treatment evaluation periods are sometimes too short, multipurpose treatments are not used to maximize effects, and treatments are often not located in appropriate sites.

}, keywords = {aerial photography, New Mexico, rangeland remediation, remote sensing, shrub removal, water spreading}, doi = {10.1006/jare.2001.0865}, url = {/files/bibliography/02-070.pdf}, author = {A. Rango and Sarah Goslee and Jeffrey E. Herrick and M. Chopping and Kris Havstad and L. Huenneke and Gibbens, Robert P. and Reldon F. Beck and R.P. McNeely} } @article {50946, title = {Riparian plant community patterns: A case study from southeastern Arizona}, journal = {Arizona-Nevada Academy of Science Journal}, volume = {34}, number = {2}, year = {2002}, month = {December 1, 2002}, pages = {106-111}, abstract = {There is concern about the preservation and, when necessary, restoration of riparian areas in semiarid regions. Understanding patterns of plant species composition and distribution within riparian corridors is helpful in planning for the management and protection of buffer strips that reduce the delivery of sediments to stream systems, maintain streambank stability, and filter excess nutrients that occur in runoff water. To determine how plant community patterns varied along environmental gradients in a semiarid riparian ecosystem, 192 quadrats located on transects radiating away from a mixed perennial and intermittent stream system were sampled for woody and herbaceous plants. Principal Components Analysis (PCA) was used to display community patterns based on species composition and distribution. Three communities of woody plants were observed across hydrologic and elevational gradients: a shrub-dominated Mimosa biuncifera community, a woodland community dominated by Prosopis velutina, and a riparian community dominated by Platanus wrightii. Patterns of herbaceous plants were not related to these gradients.}, url = {/files/bibliography/02-073.pdf}, author = {K. A. Snyder and Guertin, D. P. and Jemison, R.L. and Ffolliott, P.F.} } @conference {50955, title = {Response of perennial grasses to precipitation in the northern Chihuahuan Desert: implications for grassland restoration}, booktitle = {87th Annual Meeting, Ecological Society of America}, year = {2002}, month = {August 4, 2002}, pages = {302}, address = {Tucson, AZ}, abstract = {Grasslands in the Chihuahuan Desert of the southwestern US have been invaded by less palatable shrubs over the past 50-100 years. Sustainable management and remediation of rangelands require detailed understanding of how various factors drive the conversion of grasslands to shrublands or allow grasslands to persist through time. We compared the impacts of precipitation on perennial grass cover by species during the course of shrub invasion with responses of grasses in areas where they have persisted. At the Jornada Experimental Range, NM, 106 1-m2 permanent quadrats were set up during 1915-1932 across a range of vegetation and soil texture types. Quadrats have been monitored periodically to quantify changes in cover through time. We separated the quadrats into two groups for the analysis: (1) quadrats that maintained dominance by perennial grasses through time, and (2) quadrats that were originally located in grasslands but were dominated by shrubs in 1995. We compared long-term data from 21 rain gauges with the vegetation data to identify the periods of rainfall to which abundance and growth of dominant species were the most sensitive for each species. Basal areas of black grama, mesa dropseed, and tobosa were correlated with long-term annual precipitation; the highest coefficients occurred with cumulative rainfall in the previous 6 to 8 years. Annual growth rates of these species were correlated with short-term rainfall occurring within the previous 15 months. Black grama response to precipitation was homogeneous among quadrats in persistent grasslands but heterogeneous among quadrats where shrubs currently dominate. Our results have important implications for remediation of desert grasslands since knowledge of grass responses to precipitation can be used to identify the windows of opportunity to initiate remediation projects.}, author = {Jin Yao and Debra C. Peters and Gibbens, Robert P. and Kris Havstad} } @article {50986, title = {Response of individual Bouteloua gracilis (gramineae) plants and tillers to small disturbances}, journal = {American Midland Naturalist}, volume = {145}, number = {1}, year = {2001}, month = {January 1, 2001}, pages = {147-158}, abstract = {We evaluated effects of small disturbances that kill parts of individual plants on plant survival by measuring tiller survival for the perennial bunchgrass, Bouteloua gracilis (H.B.K.) Lag ex Griffiths (blue grama). The importance of soil texture, grazing by cattle, disturbance type, and severity were evaluated. Two disturbance types (covering or removing tillers) and three disturbance severities (50, 75, and 90\% tiller mortality) were used to represent effects of natural disturbances in shortgrass communities (cattle fecal pats, nest sites of Western harvester ants, burrows of small animals). Tiller survival through time was not affected by soil texture or grazing intensity, but was affected by disturbance type and severity. Plants that were partially covered showed a 33\% increase in tiller survival for all levels of severity from August (1991) to June (1992). No net change in tiller number was observed for partially removed or control plants. The number of tillers produced was small, but significant (avg=20 tillers/plant), which suggests that B. gracilis plants do not contain independent tillers, but consist of integrated physiological units (IPUs). The lack of plant mortality even with 90\% tiller mortality indicates that small disturbances must kill entire plants before gaps in resource space are produced, and gap dynamics are initiated that result in the recovery of an individual B. gracilis plant. Because recovery through seedling establishment by B. gracilis occurs infrequently, the ability of this species to survive after partial plant mortality is important to its continued dominance of shortgrass steppe communities in the presence of these small, but frequent disturbances.}, keywords = {Bouteloua gracilis (gramineae), cattle grazing, disturbances, soil texture}, url = {/files/bibliography/02-017.pdf}, author = {J.L. Fair and Debra C. Peters and W. K. Lauenroth} } @article {50988, title = {Root systems of some Chihuahuan Desert plants}, journal = {Journal of Arid Environments}, volume = {49}, number = {2}, year = {2001}, month = {October 1, 2001}, pages = {221-263}, abstract = {Root systems of 11 shrub or shrub-like species, 11 grass species, 19 perennial forb species and 4 annual forb species were excavated on the Jornada Experimental Range in the northern Chihuahuan Desert in southern New Mexico, USA. Maximum radial horizontal spread of shrub root systems usually occurred above calcic and petrocalcic horizons at depths above 1 m. .With one exception, all shrub species roots were traced through calcic and petrocalcic horizons to depths down to 5 m. Upward growing roots reaching very shallow depths (\< 10 cm) were common for most shrub species. Thus, the shrubs can readily access soil water and nutrients from both surface and deep soil horizons. Grass root systems on sandy soils extended radially up to 1.4 m, perhaps an adaptation to capture more soil water from the frequent small rainfall events. Grass roots did not extend through calcic or petrocalcic horizons and none penetrated deeper than 1.6 m. Perennial forb root systems varied in depth of branching but often penetrated into o through calcic and petrocalcic horizons and, like shrubs, have an advantage over grasses during droughts. Root systems of the annual forbs, excavated at the end of a season of above average precipitation, reached depths of 0.5 to 1.2 m. At each of the 18 excavation sites the roots of all the plant life forms were highly intermingled in the upper soil horizons, indicating that competition for water and soil nutrients is intense. It is believed that the plasticity and architecture of the shrub root systems, enabling them to compete with the grasses for soil water in the upper soil horizons and also access soil water at depths beyond the reach of grass roots, has been a major reason for the increase of shrubs during the historical period in this arid environment.}, keywords = {Chihuahuan Desert, competition, forbs, grasses, Jornada, root systems, shrubs, soil resources}, doi = {10.1006/jare.2000.0784}, url = {/files/bibliography/01-023.pdf}, author = {Gibbens, Robert P. and J.M. Lenz} } @article {50996, title = {Refuse to refuge: dry season use and modification of cattle dung by subterranean termites in Guanacaste, Costa Rica}, journal = {Biotropica}, volume = {33}, number = {1}, year = {2001}, month = {March 1, 2001}, pages = {121-130}, abstract = {Baits and soil cores were used to quantify temporal variation in the use of cattle dung by two species of subterranean termites, Amitermes beaumonti and Hoplotermes sp. nov., during the 1991 dry season in Guanacaste, Costa Rica. The densities of termite foragers of both species were evaluated in cattle dung patches, in the soil beneath each patch (litter, 0 to 3.5 cm and 3.5 to 7 cm) and in the same layers from adjacent dung-free control sites. Dung patch and control plots were sampled 3, 10, 60 or 110 days after 1450 ml dung patches were deposited on the pasture. Amitermes foragers were abundant in 3, 10, 60 and 110 day old dung patch plots with a mean (median) +/- SD of 100 (59) +/- 120 individuals per bait plot and only 8 (3) +/- 11 individuals per control plot. Hoplotermes foragers were less abundant, with a mean of 22 (0) +/- 87 individuals in dung patch plots and 2 (0) +/- 9 in control plots. Hoplotermes was most abundant in the surface litter under 10-day-old dung patches where an average of 39 (0) +/- 105 individuals were found. In association with dung patches, Amitermes density was highest inside or directly beneath the dung patch and lowest in the 3.5 to 7 cm microsite. In control areas, however, Amitermes was most abundant in the 3.5 to 7 cm microsite. Amitermes and Hoplotermes were found in 35 and 9 of the 54 control plots, respectively. We believe the high termite densities associated with cattle dung patches can be explained by the energetic and microclimatic requirements of the termites and the physical structure of the dung. Although neither species of termite is a mound builder, these termites use specialized behaviors to exploit and modify dung patches such that foragers have access to concentrated food resources and partial protection from the dry climate and invertebrate predators.}, url = {/files/bibliography/01-027.pdf}, author = {Gould, K.A. and Jeffrey E. Herrick and Lezama, H.} } @article {51003, title = {Rangeland soil quality--Aggregate stability (Soil Quality Information Sheet, Rangeland Sheet 3)}, year = {2001}, month = {May 2001}, publisher = {USDA, Natural Resources Conservation Service}, abstract = {Soil aggregates are groups of soil particles that are bound to each other more strongly than to adjacent particles. Aggregate stability refers to the ability of aggregates to resist degradation. Additions of organic matter to the soil enhance the stability of aggregates. Raindrops, flowing water, and windblown sand grains can break apart soil aggregates, exposing organic matter to decomposition and loss. Stable aggregates are critical to erosion resistance, water availability, and root growth. Aggregate stability in rangelands is commonly measured on soil samples removed from the top one-fourth to one-half inch of the soil. This part of the soil is most likely to be removed by wind or water erosion. Deeper samples can also be analyzed. Samples should be collected both from beneath plants and from spaces between plants. Several samples should be collected from each area. The stability of aggregates is affected by soil properties that change relatively little and by properties that change in response to changes in vegetation and management. As a result, measurements of the aggregate stability of a given soil should be compared only with measurements for the same or similar soils with similar textures. Improving the productivity of rangeland through good range management normally increases aggregate stability. Include practices that maintain the optimum amount of live vegetation and litter in order to maintain the content of organic matter and soil structure and control erosion; decrease the number and size of bare areas; and, minimize soil surface disturbances, especially in arid areas.}, keywords = {government publication}, url = {http://soils.usda.gov/sqi/management/files/RSQIS3.pdf}, author = {Jeffrey E. Herrick and A.J. Tugel and P. L. Shaver and M. Pellant} } @article {51002, title = {Rangeland soil quality--Indicators for assessment and monitoring (Soil Quality Information Sheet, Rangeland Sheet 2)}, year = {2001}, month = {May 2001}, publisher = {USDA, Natural Resources Conservation Service}, abstract = {Indicators are key soil or plant community characteristics sensitive to environmental change. They reflect complex ecosystem processes too difficult or expensive to be measured directly. They provide information about the current status of rangeland ecosystems. Trends from indicators measured regularly provide clues about the response of the system to anagement. Soil quality indicators complement vegetation indicators and may be qualitative or quantitative.}, keywords = {government publication}, url = {http://soils.usda.gov/sqi/management/files/RSQIS2.pdf}, author = {Jeffrey E. Herrick and A.J. Tugel and P. L. Shaver and M. Pellant} } @article {51005, title = {Rangeland soil quality--Infiltration (Soil Quality Information Sheet, Rangeland Sheet 5)}, year = {2001}, month = {May 2001}, publisher = {USDA, Natural Resources Conservation Service}, abstract = {Infiltration rate is simply how fast water enters the soil and is usually measured in inches or millimeters per hour. This rate depends on soil texture (amount of sand, silt, and clay) and on soil structure. Soils in good condition have well developed structure and continuous pores to the surface. As a result, water from rainfall or snowmelt readily enters these soils. The proportion of water from rainfall or snowmelt that enters the soil depends on residence time (how long the water remains on the surface before running off) and the infiltration rate. These are affected by vegetation and many soil properties. The soil and vegetation properties that currently limit infiltration and the potential for increasing the infiltration rate must be considered in any management plan. Where waterflow patterns have been altered by a shift in vegetation, such as a shift from grassland to open-canopy shrub land, restoration of higher infiltration rates may be difficult or take a long period, especially if depletion of organic matter and/or soil loss have occurred. Excessive grazing of forage can impair infiltration. Management strategies include: increase the amount of plant cover, especially of plants that have positive effects on infiltration; decrease the extent of compaction by avoiding intensive grazing and the use of machinery when the soils are wet; decrease the formation of physical crusts by maintaining or improving the cover of plants or litter and thus reducing the impact of raindrops; and, increase aggregate stability by increasing the amount of organic matter added to the soil through residue decomposition and vigorous root growth.}, keywords = {government publication}, url = {http://soils.usda.gov/sqi/management/files/RSQIS5.pdf}, author = {Jeffrey E. Herrick and A.J. Tugel and P. L. Shaver and M. Pellant} } @article {51000, title = {Rangeland soil quality--Introduction (Soil Quality Information Sheet, Rangeland Sheet 1)}, year = {2001}, month = {May 2001}, publisher = {USDA, Natural Resources Conservation Service}, abstract = {Soil Quality Information Sheets for rangelands describe soil properties that change in response to management and vegetation change. The sheets provide information related to a number of indicators used in rangeland health assessments. They support rangeland inventories and monitoring and provide possible management strategies for planning purposes. The introduction defines rangeland, rangeland health, soil, soil quality and explains how rangeland health and soil quality are interdependent.}, keywords = {government publication}, url = {http://soils.usda.gov/sqi/management/files/RSQIS1.pdf}, author = {Jeffrey E. Herrick and A.J. Tugel and P. L. Shaver and M. Pellant} } @article {51007, title = {Rangeland soil quality--Water erosion (Soil Quality Information Sheet, Rangeland Sheet 9)}, year = {2001}, month = {May 2001}, publisher = {USDA, Natural Resources Conservation Service}, abstract = {Water erosion is the detachment and removal of soil material by water. The process may be natural or accelerated by human activity. The rate of erosion may be very slow to very rapid, depending on the soil, the local landscape, and weather conditions. Water erosion wears away the earth{\textquestiondown}s surface. Sheet erosion is the more or less uniform removal of soil from the surface. Rill and gully erosion occurs when concentrated runoff cuts conspicuous channels into the soil. Deposition of the sediment removed by erosion is likely in any area where the velocity of running water is reduced: behind plants, litter, and rocks; in places where slope is reduced; or in streams, lakes, and reservoirs. Erosion is caused by the impact of raindrops on bare soil and by the power of running water on the soil surface. Each specific soil has its own natural erosion rate. A sandy or clayey texture generally is less erodible than loam or silt loam. Sandy soils that formed in material weathered from decomposed granitic rock, however, are highly erodible. Soils with rock fragments or biological crusts on the surface are protected from the impact of raindrops. Stable soil aggregates bound together by organic matter resist erosion, enhance infiltration, and result in less runoff. Bare soil between plants is most susceptible to erosion. The risk of erosion and the potential for recovery after erosion must be considered in any management plan. The risk of erosion is increased by a fire frequency or intensity that is either greater or less than is expected for the site; by disturbances, such as heavy grazing; and by the establishment of weeds. Areas with fertile topsoil are most likely to recover after a disturbance. In areas where much of the topsoil is lost, the site may no longer be able to support the historic vegetation. Management strategies include: Maintain or increase the cover of plants or litter on the soil through the application of good rangeland management practices. Reduce soil surface disturbances, especially in arid areas. Increase the rate of water infiltration and improve soil aggregate stability by improving or maintaining the quality of the plant community. Minimize grazing and traffic when the soil is wet and thus prevent the reduced infiltration caused by compaction and physical crusting. Build water bars and direct waterflow from roads, trails, or vehicle tracks across the slope or into existing drainageways. Maintain road surfaces and drainageways.}, keywords = {government publication}, url = {http://soils.usda.gov/sqi/management/files/RSQIS9.pdf}, author = {Jeffrey E. Herrick and A.J. Tugel and P. L. Shaver and M. Pellant} } @article {51008, title = {Rangeland soil quality--Wind erosion (Soil Quality Information Sheet, Rangeland Sheet 10)}, year = {2001}, month = {May 2001}, publisher = {USDA, Natural Resources Conservation Service}, abstract = {Wind erosion is the physical wearing of the earth{\textquoteright}s surface by wind. Wind erosion removes and redistributes soil. Small blowout areas may be associated with adjacent areas of deposition at the base of plants or behind obstacles, such as rocks, shrubs, fence rows, and roadbanks. In many cases the fine soil particles and organic matter are blown offsite or into the atmosphere as dust. Reducing the amount of bare ground by increasing the extent of vegetation, litter, and biological crusts reduces the risk of wind erosion. Wind erosion can occur only when windspeed at the soil surface is sufficient to lift and transport soil particles. Moist soils and soils with stable aggregates or rock fragments are less likely to be eroded than other soils. Thick lichen crusts provide greater resistance to erosion than thin crusts. Sand moving across the soil surface wears away soil aggregates and thin crusts, causing more soil particles to become detached and to be blown away. A cover of plants disrupts the force of the wind. Soils are more susceptible to wind erosion where disturbance exposes individual particles and soil aggregates to the wind. When physical or biological crusts are crushed or broken apart by such disturbances as heavy grazing, vehicle or foot traffic, and water erosion, particle movement begins at the lower windspeeds. The following conditions increase the susceptibility of the soil to wind erosion: crushed or broken soil surface crusts during windy periods; a reduction in the plant cover, biological crusts, and litter, resulting in bare soil; a decrease in the amount of organic matter in the soil, causing decreased aggregate stability; and long, unsheltered, smooth soil surfaces. The risk of erosion and the potential for recovery after erosion must be considered in any management plan. Disturbances, such as heavy grazing, fire that removes too much plant cover and litter, or vehicle and foot traffic, can increase the risk of wind erosion. Physical crusts protect the soil from wind erosion but can retard plant establishment. Areas with fertile topsoil are most likely to recover after a disturbance. Where much of the topsoil is lost, the site may no longer be able to support the historic vegetation. Management strategies include: Maintain or increase the protective cover of plants and litter on the soil through the application of good rangeland management practices. Reduce disturbances of physical and biological crusts, especially in arid areas. Maintain soil aggregate stability by improving or maintaining the quality of the plant community.}, keywords = {government publication}, url = {http://soils.usda.gov/sqi/management/files/RSQIS10.pdf}, author = {Jeffrey E. Herrick and A.J. Tugel and P. L. Shaver and M. Pellant} } @article {51047, title = {Rangeland soil quality--Physical and biological soil crusts (Soil Quality Information Sheet, Rangeland Sheet 7)}, year = {2001}, month = {May 2001}, publisher = {USDA, Natural Resources Conservation Service}, abstract = {A physical crust is a thin layer with reduced porosity and increased density at the surface of the soil. A biological crust is a living community of lichen, cyanobacteria, algae, and moss growing on the soil surface and binding it together. A chemical crust or precipitate is white or pale colored and forms in soils with a high content of salts. Both chemical and biological crusts can form on and extend into a physical crust. This information sheet deals only with physical and biological crusts. Physical crusts form when organic matter is depleted from the surface layer, soil aggregates become weak, and raindrops disperse the soil into individual particles that clog soil pores, seal the surface, and form a layer that is dense when dry. The development of objectives relative to soil crusts is an important part of rangeland management. Biological crusts protect the soil from water erosion and wind erosion. Physical crusts can protect soils from wind erosion as effectively as biological crusts, except on very coarse textured soils. In the more humid areas, it generally is desirable to break up physical crusts and thus improve seedling emergence and plant establishment; however, desirable biological crusts can be destroyed when the physical crusts are broken. Adequate organic matter, seeds of desirable species, and a period of rest are needed for successful establishment of plants after crusts are broken. The following management strategies apply to land used for grazing, wildlife habitat, or recreation: (1) Maintain the optimum amount of live vegetation, litter, and biological crust relative to the site potential in order to maintain the content of organic matter and soil structure and control erosion. (2) In humid areas improve soil structure and plant establishment by incorporating organic matter into the soil while breaking up a physical crust. (3) Defer grazing and recreational use during periods when biological crusts are most susceptible to physical disturbances. (4) Use prescribed burning according to the needs of each site to prevent fuel buildup that can produce hot fires followed by severe erosion. (5) Control the establishment and spread of invasive annual plants that can carry fire.}, keywords = {government publication}, url = {http://soils.usda.gov/sqi/management/files/RSQIS7.pdf}, author = {P. L. Shaver and A.J. Tugel and Jeffrey E. Herrick and M. Pellant} } @article {51051, title = {Rangeland soil quality--Compaction (Soil Quality Information Sheet, Rangeland Sheet 4)}, year = {2001}, month = {May 2001}, publisher = {USDA, Natural Resources Conservation Service}, abstract = {Soil compaction occurs when moist or wet soil aggregates are pressed together and the pore space between them is reduced. Compaction changes soil structure, reduces the size and continuity of pores, and increases soil density (bulk density). Wheel traffic or pressure (weight per unit area) exerted on the soil surface by large animals, vehicles, and people can cause soil compaction. In areas of rangeland, compacted soil layers are generally at the soil surface or less than 6 inches below the surface, although they can be as deep as 2 feet under heavily used tracks and roads. Compaction is a problem when the increased soil density and the decreased pore space limit water infiltration, percolation, and storage; plant growth; or nutrient cycling. Compacted wheel tracks or trails can concentrate runoff that can create rills or gullies, especially on steep slopes. The following features may indicate a compacted soil layer: platy, blocky, dense, or massive appearance; significant resistance to penetration with a metal rod; high bulk density; and, restricted, flattened, turned, horizontal, or stubby plant roots. Because some soils that are not compacted exhibit these features, refer to a soil survey report for information about the inherent characteristics of the soil. Dry soils are much more resistant to compaction than moist or wet soils. Soils that are wet for long periods, such as those on north-facing slopes and those on the lower parts of the landscape, where they receive runoff, are susceptible to compaction for longer periods than other soils. Natural recovery is often slow, taking years to decades or more. To minimize compaction, minimize grazing, recreational use, and vehicular traffic when the soils are wet; use only designated trails or roads and reduce the number of trips; do not harvest hay when the soils are wet; maintain or increase the content of organic matter in the soil by improving the plant cover and plant production.}, keywords = {government publication}, url = {http://soils.usda.gov/sqi/management/files/RSQIS4.pdf}, author = {A.J. Tugel and Jeffrey E. Herrick and P. L. Shaver and M. Pellant} } @article {51054, title = {Rangeland soil quality--Organic matter (Soil Quality Information Sheet, Rangeland Sheet 6)}, year = {2001}, month = {May 2001}, publisher = {USDA, Natural Resources Conservation Service}, abstract = {Soil organic matter is carbon-rich material that includes plant, animal, and microbial residue in various stages of decomposition. Live soil organisms and plant roots are part of the carbon pool in soil but are not considered soil organic matter until they die and begin to decay. Soil organic matter enhances soil functions and environmental quality because it binds soil particles together into stable aggregates, thus improving porosity, infiltration, and root penetration and reducing runoff and erosion; enhances soil fertility and plant productivity by improving the ability of the soil to store and supply nutrients, water, and air; provides habitat and food for soil organisms; sequesters carbon from the atmosphere; reduces mineral crust formation and runoff; and, reduces the negative water quality and environmental effects of pesticides, heavy metals, and other pollutants by actively trapping or transforming them. The amount of organic matter in the soil is a balance between additions of plant and animal materials and losses through decomposition and erosion. The following strategies can help to maintain the optimum content of organic matter in rangeland soils: increase or maintain plant production, promote the growth of species with high root production, promote a mix of species with different rooting depths and patterns, promote the incorporation of above-ground plant material in moist plant communities with large amounts of standing plant material (e.g., areas of tall prairie grasses), protect the soil from erosion by maintaining or increasing, the plant cover and reducing the amount of bare soil, properly manage grazing, fire, and vehicle use and thus promote the desired plant community and protect the soil from erosion.}, keywords = {government publication}, url = {http://soils.usda.gov/sqi/management/files/RSQIS6.pdf}, author = {A.J. Tugel and Jeffrey E. Herrick and P. L. Shaver and M. Pellant} } @article {51055, title = {Rangeland soil quality--Soil biota (Soil Quality Information Sheet, Rangeland Sheet 8)}, year = {2001}, month = {May 2001}, publisher = {USDA, Natural Resources Conservation Service}, abstract = {Soil biota include an incredible diversity of organisms. Soil biota are concentrated in plant litter, the upper few inches of soil, and along roots. Soil organisms interact with one another, with plant roots, and with their environment, forming the soil food web. Through their interactions in the soil food web, the activities of soil biota link soil with the plants and animals above ground. Soil organisms perform essential functions that allow soil to resist degradation and provide benefits to all living things. Soil biota multiply rapidly when organic material, roots, and plant litter, their food source, are available and the soil is moist and warm. Proper management of the plant community is the best strategy for maintaining the benefits of the soil food web. Plant production and the supply of organic matter can be maintained or enhanced by timely grazing, the proper frequency of grazing, and control of the amount of vegetation removed. If the plant community is overgrazed, a reduction in the amount of surface plant material and roots will result in less food for soil organisms. As biological activity decreases, a downward spiral of the important functions of soil organisms results in a lower content of organic matter and impedes nutrient cycling, water infiltration, and water storage. Heavy grazing also can reduce the abundance of nitrogen-fixing plants, causing a decrease in the supply of nitrogen for the entire plant community. Pesticides that kill above-ground insects can also kill beneficial soil insects. Herbicides and foliar insecticides applied at recommended rates have a smaller impact on soil organisms. Fungicides and fumigants have a much greater impact on the soil organisms.}, keywords = {government publication}, url = {http://soils.usda.gov/sqi/management/files/RSQIS8.pdf}, author = {A.J. Tugel and Jeffrey E. Herrick and P. L. Shaver and M. Pellant} } @proceedings {51066, title = {Rangeland research in the Chihuahuan Desert}, year = {2000}, month = {03/2000}, pages = {80-81}, abstract = {

The mission of the Jornada Experimental Range is to develop new technologies for the management and remediation of desert rangelands. We are developing a manual for monitoring rangeland health. Several indicators have been examined and a number of these indicators have proven useful for monitoring purposes, e.g., size of unvegetated patch, perennial grass cover rand soil surface stability. We have worked with individual ranchers in New Mexico to test these methods and have established pilot projects on state lands to demonstrate their application to management. We are also studying prescribed burning of arid rangeland as a tool to improve degraded rangelands. The fire treatment was applied to study sites in 1999 and initial responses to fire and grazing effects will be measured in 2000. We will evaluate effects of fire on ecological processes and post-fire grazing and identify post-fire guidelines for recovery of key species in grazed Chihuahuan Desert grassland. One of our major research objectives is to develop new technologies for controlling distribution of livestock grazing rangelands. Few options presently exist for monitoring animal location and controlling animal movement to a specific area at a particular time. A method and apparatus have been developed that may allow for management of grazing livestock without ground-based fencing. The device worn by an animal incorporates a global positioning system and a geographic information system database to determine and control individual animal movements. We are field testing the ability of a third generation prototype to contain an animal in an area using bilaterally applied sensory cues. This technology could allow producers to reduce management costs, improve utilization of forage and protect ecologically sensitive areas.

}, keywords = {cattle growers, Chihuahuan Desert, livestock, rangeland research, research notes}, url = {/files/bibliography/562.pdf}, author = {Richard E. Estell and D.M. Anderson and J.R. Barrow and E.L. Fredrickson and Kris Havstad and Jeffrey E. Herrick and Debra C. Peters} } @article {51070, title = {Regional snow parameters derived from microwave radiometry}, journal = {EOS Transactions, American Geophysical Union}, volume = {81}, year = {2000}, note = { //NONE//LTER IV//updated 08/04/2010}, month = {2000}, pages = {F445}, author = {J. Foster and Chang, A. T. C. and D. K. Hall and E. R. Erbe and W.P. Wergin and A. Rango} } @conference {51073, title = {Reconnaissance satellite photos show the recent history of shrub recruitment and survival in desert grasslands}, booktitle = {85th Annual Meeting, Ecological Society of America}, year = {2000}, month = {August 6-10, 200}, pages = {280}, address = {Snowbird, UT}, abstract = {Certain shrub species, particularly Prosopis glandulosa and Larrea tridentata, have increased dramatically in the southwestern US during the past few decades, replacing the original grassland vegetation. We obtained a temporal series of high-resolution military satellite images beginning in the early 1960s, with the goal of monitoring shrub invasion over a large area to determine the topographic and climatic controls on shrub seedling establishment and the rate of expansion of shrub cover. Although the total area of shrub cover increased over time, both the number of shrubs and their size distributions were highly variable. Mortality in small shrubs was high, but once shrubs reached a threshold size, they were likely to persist for long periods. Shrub establishment and survival were related to both climatic factors and topographic features, particularly precipitation and drainage. Our results provide valuable information for those interested din the management and restoration of the desert grasslands of the southwestern US.}, keywords = {desert grasslands, history, Larrea tridentata, prosopis glandulosa, reconnaissance, satellite, shrub recruitment}, author = {Sarah Goslee and Debra C. Peters and Kris Havstad and W. H. Schlesinger} } @conference {51081, title = {Relationship between soil organic matter dynamics and disturbance regime and applications to monitoring and modelling vegetation change}, booktitle = {85th Annual Meeting, Ecological Society of America}, year = {2000}, month = {August 8-10, 200}, pages = {404}, address = {Snowbird, UT}, abstract = {Soil organic matter is widely cited as a key ecosystem property which both affects and reflects water and nutrient storage and redistribution. Relationships between soil organic matter and soil structure in arid ecosystems and the effects of soil biota and disturbance are poorly understood. Our research is designed to develop an understanding of how interactions between plants, soil organic matter and soil biota affect patch-scale soil water infiltration and storage under different disturbance regimes and how variability in these processes across the landscape contributes to resource redistribution and vegetation patterns. We are applying this understanding to the development of (1) a quantitative monitoring system for grassland, shrubland and savanna ecosystems, (2) a spatially interactive gap dynamics model (ECOTONE see Peters and Herrick poster), and (3) ecologically-based remediation approaches for degraded rangeland. Our results show termites, ants and microbiotic crusts contribute significantly to the spatial variability of water infiltration and runoff and the resistance and resilience of soil properties and processes are strongly dependent on both soil type and the soil biotic community. The monitoring system includes a suite of rapid soil and vegetation indicators selected and applied on a site-specific basis and interpreted in a landscape context.}, keywords = {disturbance, interactions, modelling, monitoring, organic matter, resource redistribution, soil, vegetaton patterns}, author = {Jeffrey E. Herrick} } @article {51095, title = {The relationship between density and demographic variation within a population of Larrea tridentata}, journal = {The Southwestern Naturalist}, volume = {45}, number = {3}, year = {2000}, note = {//NMSU,USDA//LTER IV//}, month = {2000}, pages = {313-321}, abstract = {Larrea tridentata is a dominant desert shrub throughout the warm deserts of North America. We studied Larrea population we believed to be in the process of invading adjacent grasslands. To determine whether our hypothesis was correct we developed a set of predictions about characteristics of invading populations and examined the relationship between Larrea density and demographic variation. For an invading Larrea population we predicted that: 1) individuals in low density areas would exhibit attributes indicating higher intrinsic rates of increase--individuals would have greater fruit production, 2) individuals in high density areas would exhibit the effects of negative density-dependence--plants would have canopies in poor condition (with at least 20\% dead branches) and be small in size, and 3) low density areas would be below carrying capacity--plots would have a lower total Larrea biomass than high density areas. We measured height, average width, canopy condition, and fruit set for 2,000 plants sampled from 40 plots varying in density. We also estimated the total Larrea biomass for each plot. We collected data on two measures of microenvironmental variation, cover of the common grassland species, and cover of gravel on the soil surface. All plant characters were significantly correlated with Larrea density and both measures of microenvironmental variation were significantly correlated with density. In contrast, results for total Larrea biomass did not conform to our prediction. Although the relationship between Larrea density and the plant characters supported our predictions for an invading Larrea population, results for total Larrea biomass did not. An alternative explanation that the pattern of demographic variation within the study population was determined by microenvironmental variations was more strongly supported.}, keywords = {article, articles, demography, Larrea, journal, journals, Larrea encroachment, Larrea, demography, shrub, Larrea}, author = {Richard E. Miller and L. Huenneke} } @proceedings {51129, title = {The role of endophytic fungi in the survival and establishment of fourwing saltbush (Atriplex canescens [Pursh] Nutt.) in an arid environment}, year = {1999}, month = {1999}, pages = {1-4}, publisher = {USDA Forest Service, Rocky Mountain Research Station, Proceedings RMRS-P-11}, address = {Ogden, UT}, abstract = {

A seedborne septate fungus (Aspergillus sp.) formed intimate nondestructive interfaces with seedling radicles of germinating fourwing saltbush (Atriplex canescens [Pursh] Nutt.) seedlings. When seedlings were separated from insoluble phosphorus sources with a screen that excluded roots but allowed passage of extraradicle hyphae, which accessed plant insoluble phosphate and transported it through the barrier to the plant. The fungi enhanced phosphorus uptake, biomass production of the host plants and aggregated sand similar to functions attributed to mycorrhizal fungi. The importance of symbiotic fungi in the remediation and stabilization of arid ecosystems is discussed.

}, url = {/files/bibliography/690.pdf}, author = {J.R. Barrow and Feder, I. and Curtis H. Monger} } @proceedings {51140, title = {Rangeland research in the Chihuahuan Desert}, year = {1999}, month = {1999}, pages = {71-76}, abstract = {The mission of the Jornada Experimental Range is to develop new technologies for the management and remediation of desert rangelands. Effects of stressors such as drought, soil nutrient depletion and shrub competition on grassland/shrubland ecosystems are being examined. A study is in progress to examine responses of desert ecosystems to fire and the influence of cattle grazing during post-fire recovery on these responses. Several plant and soil-based indicators of ecosystem function have been identified that are being incorporated into a manual for use in monitoring rangelands. Low input/trigger site strategies are being developed for remediation of rangelands. Experiments are underway to evaluate application of dairy manure on different plant communities and effects of portable shade on cattle distribution. A study conducted in which lambs were reared in pens with slatted or solid panels indicated lambs reared in simple environments had difficulty learning new food seeking behaviors and were more stressed in new environments. We have begun to examine the use of fluorometry to improve the accuracy and speed of diet analysis. Preliminary research indicated it could be used to distinguish among fecal samples from sheep consuming simple diets. We are studying the relationship of secondary chemistry of desert shrubs and livestock herbivory. Two of the eleven terpenes that were negatively related to tarbush intake in previous studies decreased intake of alfalfa by lambs. Determining which compounds deter herbivory will help establish methods to alter diet selectivity by livestock.}, url = {/files/bibliography/651.pdf}, author = {Richard E. Estell and Kris Havstad and D.M. Anderson and J.R. Barrow and D.P. Coffin and E.L. Fredrickson and Jeffrey E. Herrick and P.W. Hyder} } @article {51143, title = {The role of kangaroo rats (Dipodomys spectabilis) in determining patterns in plant species dominance at an ecotonal boundary}, journal = {Journal of Vegetation Science}, volume = {10}, year = {1999}, month = {1999}, pages = {123-130}, author = {Fields, M.J. and Debra C. Peters and J. R. Gosz} } @conference {51146, title = {Role of herebivorous and granivorous fauna in the maintenance of mesquite coppice dune systems}, booktitle = {5th Symposium on Resources of the Chihuahuan Desert Region: U.S. and Mexico}, year = {1999}, month = {October 7-8, 199}, pages = {17-18}, address = {Alpine, TX}, abstract = {Part of the ongoing desertification process within the Chihuahuan Desert involves replacement of former grasslands by shrubs. At the U.S. Department of Agriculture, Agricultural Research Service, Jornada Experimental Range, vast areas of Black Grama, Bouteloua eriopoda, grasslands were replaced by mesquite, Prosopis glandulosa glandulosa, which hsubsequently facilitates the formation of coppice dunes or mounds of sand around established shrubs. Three studies were designed to assess the effects of two broad guilds of fauna herbivores (foliage eaters) and granivores (seed eaters) in maintaining coppice dune states. We also consider in greater detail species-specific roles played by a group of desert rodents known to have keystone effects on Chihuahuan Desert plant communities. These studies indicate the small mammals studied both maintain and probably augment coppice dune systems.}, author = {E.L. Fredrickson and Longland, W.S. and P.W. Hyder and Hu, D. and Richard E. Estell} } @article {51150, title = {Remote sensing technology for development planning along the US-Mexico border: hydrogeology and geomorphology}, journal = {New Mexico Journal of Science}, volume = {39}, year = {1999}, note = {//?//LTER III//}, month = {1999}, pages = {123-?}, abstract = {

Arid land ecosystems along the border region of the United States and Mexico are being rapidly developed. Two of the most important natural resources of this region are water and soil. Hydrogeological characteristics (such as the size and quality of aquifers) combined with geomorphic units (such as alluvial fans and floodplains), provide important information that can help prevent poorly planned development. Making these maps involves 1) delineating geomorphic features based on aerial photographs and satellite images, 2) ground-truthing the features, and 3) combining geomorphic maps with groundwater maps using GIS (Geographic Information System). These hydro-geomorphic maps help to locate high producing wells, as along faults, and identify groundwater recharge zones, as along mountain arroyos. Moreover, these hydro-geomorphic maps identify areas unsuitable for development. For example, housing development should not take place in arroyo and river floodplains, which are subject to flooding. Instead, housing sh ould occur on higher, geomorpho logically stable fan-piedmont surfaces. Building on stable surfaces not only will protect houses from flooding and erosion, but also will preserve the topographically lower and texturally finer floodplains for agriculture, wildlife, and recreation.

}, keywords = {article, articles, geomorphology, hydrogeology, journal, journals, remote sensing}, url = {files/bibliography/JRN00285.pdf}, author = {Granados-Olivas, A. and Curtis H. Monger} } @article {51193, title = {Rainfall energy under creosotebush}, journal = {Journal of Arid Environments}, volume = {43}, year = {1999}, note = {//NMSU//LTER III//}, month = {1999}, pages = {111-120}, abstract = {

Simulated rainstorms of 15 min duration and average intensity 148 mm h-1 were applied to seven creosotebushes. Intensity of the sub-canopy rainfall was reduced to 90\% of the rain falling out with the canopy, whereas the kinetic energy was reduced to 70\%. Although leafdrip makes up 28.9\% of the sub-canopy rainfall, it contributes only 10\% of the sub-canopy kinetic energy. Comparison of the effective kinetic energy (that possessed by raindrops with sufficient energy to detach sediment) beneath the canopy with that outside the canopy shows that the former is 55\% of the latter. These results quantify the process of differential splash that contributes to the build-up of mounds beneath desert shrubs, and improves the understanding of the development of islands of fertility in desert ecosystems.

}, keywords = {article, articles, erosion, raindrop, journal, journals, Larrea, rainfall interception, Larrea, rainfall simulation, Larrea, throughfall, rainfall energy, rainfall simulation, Larrea, throughfall, Larrea}, doi = {10.1006/jare.1999.0540}, url = {files/bibliography/JRN00284.pdf}, author = {John Wainwright and A.J. Parsons and Athol D. Abrahams} } @article {51210, title = {Regional productivities of plant species in the Great Plains of the United States}, journal = {Plant Ecology}, volume = {134}, number = {2}, year = {1998}, month = {February 1, 1998}, pages = {173-195}, abstract = {Few studies have analyzed the production of plant species at regional scales in grassland ecosystems, due in part to limited availability of data at large spatial scales. We used a dataset of rangeland surveys to examine the productivities of 22 plant species throughout the Great Plains of the U.S. with respect to three environmental factors: temperature, precipitation, and soil texture. Productivity and soil texture were obtained from NRCS range site descriptions and STATSGO databases. Climate data were obtained from 296 weather stations located throughout the region. Mean annual temperature was the most important explanatory variable for 55\% of species analyzed. Mean annual precipitation was most explanatory for 40\% of the species. Productivity of C3 species was negatively related to climate and positively related to clay content. Production of C4 shortgrasses was positively related to temperature and negatively related to precipitation and sand content. By contrast, production of C4 tallgrasses was positively related to precipitation and sand and highest at intermediate values of temperature. The regression equations developed from these analyses are important inclusions in models that assess effects of climate change on plant communities throughout the region.}, url = {/files/bibliography/98-001.pdf}, author = {Howard Epstein and W. K. Lauenroth and Ingrid C. Burke and D.P. Coffin} } @proceedings {51211, title = {Rangeland research in the Chihuahuan Desert}, year = {1998}, month = {1998}, keywords = {cattle growers{\textquoteright} short course, Chihuahuan Desert, rangeland, research}, author = {Richard E. Estell and D.M. Anderson and J.R. Barrow and A.G. de Soyza and E.L. Fredrickson and Gibbens, Robert P. and Kris Havstad and Jeffrey E. Herrick and M.R. Tellez and Walter G. Whitford} } @article {51213, title = {Relationship of tarbush leaf surface terpene profile with livestock herbivory}, journal = {Journal of Chemical Ecology}, volume = {24}, number = {1}, year = {1998}, month = {January 1, 1998}, pages = {1-12}, abstract = {

Tarbush (Flourensia cernua DC.) is a Chihuahuan Desert shrub with a resinous leaf surface containing terpenes that may affect livestock herbivory. Cattle, sheep, and goats were densely stocked in paddocks containing tarbush in two consecutive years for six to nine days and defoliation of 160 plants was recorded daily. Plants were categorized as exhibiting high or low defoliation. Leaves were collected from these plants the third year for chemical analysis. A selection procedure was used to generate two variable sets closely related to defoliation category. One set contained 14 variables (dry matter, ash, -pinene, sabinene, 3-carene, p-cymene, limonene, camphor, bomeol, cis-jasmone, {\^a} -caryophyllene, alpha-humulene, ledene, and flourensadiol) and the other set contained 14 unidentified compounds. When subjected to multivariate analysis, each group distinguished between the two defoliation categories (P \<0.001 and P \<0.0019 for known and unknown variable sets, respectively). These data support the hypothesis that leaf surface chemistry of individual tarbush plants is related to extent of defoliation by livestock.

}, keywords = {diet selection, Epicuticular wax, Flourensia cernua, leaf surface chemistry, monoterpenes, sesquiterpenes}, doi = {10.1023/A:1022399426352 }, url = {/files/bibliography/608.pdf}, author = {Richard E. Estell and E.L. Fredrickson and D.M. Anderson and Kris Havstad and M.D. Remmenga} } @inbook {51224, title = {Rangeland Soil Erosion and Soil Quality: Role of Soil Resistance, Resilience, and Disturbance Regime}, booktitle = {Soil Quality and Soil Erosion}, year = {1998}, month = {September 24, 19}, pages = {209-233}, publisher = {CRC Press}, organization = {CRC Press}, chapter = {13}, address = {Columbus, OH}, abstract = {

The relationships between rangeland soil quality, soil resilience, and soil erosion depend on several interacting factors: (1) landscape and climate characteristics, (2) current disturbance regime, and (3) recent and evolutionary disturbance history. These factors tend to be more variable across rangelands than across agricultural lands. There are at least four specific relationships between soil quality and soil erosion which involve soil resistance or soil resilience. The first is the historical resistance of the soil to past disturbances, which can serve as an indicator of soil quality. Second, the current resistance of the soil to disturbance is related to soil erosion potential. The third relationship is the current resilience of the system following soil erosion. Finally, soil erosion is a driver in the system which determines soil quality. This final relationship illustrates the need to view the system dynamically: soil erosion both reflects and affects soil quality. These dynamic relationships depend, in turn, on the characteristics of historic and current disturbance regimes. Both ecosystems and species tend to evolve in response to dominant disturbance regimes, such as fire, drought, and grazing. The resistance and/or resilience of the system will tend to be higher for disturbance regimes which share key characteristics with historic and evolutionary patterns.

}, url = {/files/bibliography/663.pdf}, author = {Jeffrey E. Herrick and M.A. Weltz and Reeder, J.D. and G.E. Schuman and Simanton, J.R.} } @conference {51223, title = {Role of ants and termites in improving soil water infiltration}, booktitle = {Society for Range Management}, year = {1998}, month = {1998}, pages = {54}, abstract = {Rangeland degradation is frequently associated with reduced water infiltration at both the microsite and landscape levels. Many soil invertebrates create macropores which can conduct water more quickly into the soil. The objective of this study was to determine whether the macropores created by termites and harvester ants significantly increase infiltration. A tension infiltrometer was used to quantify macropore contribution to soil water infiltration under natural and artificial baits with increased termite activity, and in and around harvester ant (Pogonomyrmex rugosus) nests on compacted soils. There was no treatment effect on infiltration rates into a sandy loam when water was applied at tensions which only filled pores smaller than those created by termites (approximate pore equivalent cylindrical diameter <250u; 25-43mm/hr; p>0.1). However, when the contribution of macropores attributable to termite activity was included (5mm tension; e.c.d.<6mm), the infiltration capacity in areas with enhanced termite activity increased two- to three-fold on the sandy loam (33 vs. 66-102mm/hr; p<0.01). Similar enhancements in infiltration capacity were recorded at the silty clay site, and on harvester ant mounds suggesting that soil-dwelling termites and ants may play a role similar to that of earthworms in more mesic systems.}, author = {Jeffrey E. Herrick and Walter G. Whitford} } @mastersthesis {JRN54900, title = {The role of Bouteloua eriopoda in the community structure and ecosystem function of a semi-arid grassland}, volume = {M.S.}, year = {1997}, pages = {75}, school = {New Mexico State University}, type = {Thesis}, address = {Las Cruces}, keywords = {black grama grass, Bouteloua eriopoda, community structure, ecosystem function, grassland ecology, JRN LTER}, author = {Baggs, Joanne E.} } @proceedings {51272, title = {Rangeland research in the Chihuahuan Desert}, year = {1997}, month = {1997}, keywords = {cattle growers{\textquoteright} short course, Chihuahuan Desert, rangeland, research}, author = {Richard E. Estell and D.M. Anderson and J.R. Barrow and A.G. de Soyza and E.L. Fredrickson and Gibbens, Robert P. and Kris Havstad and Jeffrey E. Herrick and M.R. Tellez and Walter G. Whitford} } @inbook {51285, title = {Relationships between soil organic carbon and soil quality in cropped and rangeland soils: the importance of distribution, composition, and soil biological activity}, booktitle = {Soil Processes and the Carbon Cycle}, year = {1997}, month = {1997}, pages = {405-425}, publisher = {CRC Press LLC}, organization = {CRC Press LLC}, chapter = {28}, address = {New York, NY}, abstract = {The often-cited positive relationship between soil organic carbon (SOC) content and soil quality (Arshad and Coen, 1992; National Research Council, 1993; Doran and Parkin, 1994; Manley et al., 1995; Pikul and Aase, 1995; Karlen and Cambardella, 1996) is consistent with the results of over one hundred years of modern agricultural research (Bauer and Black, 1994) and with thousands of years of on-farm observation and experimentation (Magdoff, 1992). This relationship is based on contributions which SOC makes as a constituent of soil organic matter (SOM) to critical soil properties, processes and functions. The term "SOM" will be used in the remainder of this chapter except where carbon per se is of interest. SOM is preferred here because it reflects the reality that impacts of SOC on soil quality are determined by its chemical, physical, and biological configuration within SOM. The positive correlation between SOM and soil quality holds, in general, for all of the definitions of soil quality listed by Doran and Parkin (1994), as well as for the concepts of soil quality discussed by Warkentin (1995). Soil organic matter content was listed by a group of 28 Wisconsin farmers as the single most important property for characterizing soil health or soil quality based on their personal definitions (Romig et al., 1995). SOM was also cited as "perhaps the single most important indicator of soil quality" in a National Research Council report on soil and water quality. The report defined soil quality as "the capacity of the soil to promote the growth of plants; protect watersheds by regulating the infiltration and partitioning of precipitation; and prevent water and air pollution by buffering potential pollutants such as agricultural chemicals, organic wastes, and industrial chemicals" (National Research Council, 1993). For the purposes of this chapter, soil quality is defined as the capacity of a soil to perform functions which sustain biological productivity and maintain environmental quality. Soil quality depends on current soil functional integrity and on soil{\textquoteright}s resistance to, and resilience following, perturbation. Resistance is inversely proportional to loss of soil functional integrity following perturbation, while resilience is proportional to the recovery of functional integrity (Figure 1; Pimm, 1984). It is clear that a general relationship exists between SOM content, soil functions, and the capacity of the soil to maintain and/or recover those functions over time.}, url = {/files/bibliography/525.pdf}, author = {Jeffrey E. Herrick and Wander, M.M.}, editor = {R. (ed.) Lal and Kimble, J.M. and Follett, R.F. and Stewart, B.A.} } @article {51286, title = {Rethinking remediation technologies for desertified landscapes}, journal = {Water Conservation}, volume = {52}, year = {1997}, month = {1997}, pages = {220-225}, abstract = {

Shrub dominated communities have replaced native grasslands throughout much of the arid Southwest during the past 120 years. Most currently available remediation technologies are uneconomical due to large inputs of energy, fertilizers, herbicides adn labor or are ecologically ineffective due to harsh environments adn the highly competitive nature of these native shrubs. Our analysis of these historical remediation technologies together with new information on ecosystem processes has led us to pursue an ecologically-based approach in which more limited inputs are targeted to promote natural processes of regeneration. Advantages to this approach include lower costs, reduced reliance on agronomic practices, and maintenance of natural landscape features. Disadvantages include longer time required for desired changes to occur, and a need for increased understanding of arid land processes.

}, url = {/files/bibliography/586.pdf}, author = {Jeffrey E. Herrick and Kris Havstad and D.P. Coffin} } @conference {51284, title = {Review of soil quality research and potential for assessing and monitoring soil quality on rangeland}, booktitle = {50th Annual Meeting, Society for Range Management}, year = {1997}, month = {1997}, pages = {4}, abstract = {Current interest in developing inter-agency assessment and monitoring programs for U.S. rangelands is paralleled by similar efforts to develop a national system to monitor soil quality. The Soil Science Society of America defines soil quality as "the capacity of a soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation." The NRCS, ARS, BLM, ERA and a variety of universities, nonprofit and private organizations are currently testing indicators of the capacity of soils to support a broad range of ecosystem functions. Most work on soil quality has focused on annual croplands. The fundamental importance of soil and water conservation and plant productivity to the sustainability of both croplands and rangelands suggests that some indicators should be suitable for both types of ecosystems. Efforts are currently underway to (1) adapt and modify cropland soil quality indicators for use on rangelands, (2) develop additional (especially vegetation-based) indicators which better reflect the unique characteristics of rangeland soil processes, and (3) integrate rangeland and cropland soil quality assessment and monitoring systems to generate a program which can be applied at the national level.}, author = {Jeffrey E. Herrick and Mausbach, M.J.} } @article {JRN54982, title = {The response of areal snow cover to climate change in a snowmelt-runoff model}, journal = {Annals of Glaciology}, volume = {25}, year = {1997}, pages = {232-236}, chapter = {232}, abstract = {

The cryosphere is represented in some hydrological models by the areal extent of snow cover, a variable that has been operationally available in recent years through remote sensing. In particular, the snowmelt-runoff model (SRM) requires the remotely sensed snow-cover extent as a major input variable. The SRM is well-suited for simulating the hydrological response of a basin to hypothetical climate change because it is a non-calibrated model. In order to run the SRM in a climate-change mode, the response of the areal snow cover to a change in climate is a critical, and must be calculated as a function of elevation, precipitation, temperature, and snow-water equivalent. For the snowmelt-runoff season, the effect of climate change on conditions in the winter months has a major influence. In a warmer climate, winter may experience more rain vs snow events, and more periods of winter snowmelt that reduce the snow water equivalent present in the basin at the beginning of spring snowmelt. As a result, the spring snowmelt runoff under conditions of climate warming will be affected not only by different temperatures and precipitations, but also by a different snow cover with a changed depletion rate. A new radiation-based version of the SRM is under development that will also take changes in cloudiness and humidity into account, making climate-change studies of the cryosphere even more physically based. \ 

}, url = {files/bibliography/Rango1997-03.pdf}, author = {A. Rango} } @conference {51308, title = {Responses of Chihuahuan Desert annual plant communities to desertification and exposure to varying grazing stress.}, booktitle = {International Symposium and Workshop Combating Desertification: Connecting Science with Community Action}, year = {1997}, month = {May 12-16, 1997}, pages = {23}, address = {Tucson, AZ}, abstract = {

Ephemeral or annual plant communities respond to a variety of environmental factors, including rainfall, nutrients, temperature, competition, and disturbance. Stressors such as cattle grazing can alter perennial plant communities and soil properties sufficiently to change annual plant communities. We examined density and biomass of annual plant species at sites representing historically documented desertification (a degradation gradient), grazing intensity gradients, grazing exclosures and enclosures, rangeland rehabilitation efforts, and recent fires, as well as sites representing habitats unique to the Chihuahuan Desert. Traditional community vegetation parameters such as species richness and indices of species diversity do not always effectively explain patterns in annual plant communities.\ \  We emphasize examination of key species and micro habitat patterns when analyzing the effects of disturbance of ephemeral plant communities and include examples of how ephemeral plants respond to patchy environments in a wide range of habitats and landscape positions in Chihuahuan Desert rangelands.

}, author = {Justin Van Zee and A.G. de Soyza and Walter G. Whitford} } @proceedings {51319, title = {Role of microbes in resource management in arid ecosystems}, volume = {Gen. Tech. Rep. INT-GTR-338}, year = {1996}, month = {May 23-25, 1995}, pages = {1-2}, publisher = {USDA Forest Service, Intermountain Research Station, Gen. Tech. Rep. INT-GTR-338}, address = {Las Cruces, NM}, abstract = {

Three major classes of endophytic fungi were observed in the roots of native grasses and shrubs: (1) vesicular-arbuscular mycorrhizae (VAM), which are known to be important in water and nutrient uptake; (2) septate fungi that formed non-destructive interfaces within root cortex cells and exhibited mycorrhizal like characteristics; and (3) chytridiomycetes were the third major class of fungi observed and preliminary studies suggest they regulate colonization of VAM, septate fungi, and nutrient uptake.\  A hypothesis is proposed on how these fungi function in accessing and managing nutrients and water for survival in arid ecosystems.

}, url = {/files/bibliography/457.pdf}, author = {J.R. Barrow and McCaslin, B D.}, editor = {J.R. Barrow and McArthur, E. Durant and R. E. Sosebee and R. J. Tausch} } @article {JRN54988, title = {Response of Snowmelt Hydrology to Climate Change}, journal = {Water, Air and Soil Pollution}, volume = {90}, year = {1996}, pages = {335-343}, chapter = {335}, abstract = {

In mountainous regions where the accumulation and melt of seasonal snow cover are important for runoff production, the timing and quantity of water supply could be strongly affected by regional climate change, particularly altered temperature and precipitation regimes. In this paper, the hydrological response to climate change scenarios is examined using a semi-distributed snowmelt runoff model. The model represents an improvement over simple temperature-based models, in that it incorporates the net radiation into the snowpack. Thus it takes into account the basin{\textquoteright}s topography and slope orientation when computing snowmelt. In general, a warmer climate is expected to shift snowmelt earlier into the winter and spring, decreasing summer runoff. The effects of other potential climate changes (such as precipitation and cloudiness patterns) are explored. The uncertainties in these predictions are discussed. \ 

}, keywords = {climate change, net radiation, runoff, snow cover, snowmelt, water supply}, url = {files/bibliography/Rango1996-08.pdf}, author = {K.L. Brubaker and A. Rango} } @proceedings {51340, title = {Rangeland improvement}, year = {1996}, month = {March 28-29, 199}, keywords = {cattle growers, livestock research briefs, short course}, author = {Kris Havstad and D.M. Anderson and J.R. Barrow and Richard E. Estell and E.L. Fredrickson and Jeffrey E. Herrick and Walter G. Whitford} } @proceedings {51337, title = {Reflections on a century of rangeland research in the Jornada Basin of New Mexico}, volume = {Gen. Tech. Rep. INT-GTR-338}, year = {1996}, month = {May 23-25, 1995}, pages = {10-15}, publisher = {USDA Forest Service, Intermountain Research Station, Gen. Tech. Rep. INT-GTR-338}, address = {Las Cruces, NM}, abstract = {

A historical analysis can generally take one of three formats: 1)narrative, 2)context, or 3)analog. As narrative, the analysis is limited to a description detailing events. As context, historical analysis explains the present state based on interpretations of its varied history. As analog, the analysis attempts to support predictions regarding future conditions. The narrative format is the safest in that it typically involves the least interpretation and assumption, especially if the historical record is well documented. The context format can be the most enlightening. The analog, though, is the most useful, and the most precarious, and shares the central premise of scientific experimentation, the desire to make predictions about the future. The Jornada Experimental Range{\textquoteright}s history overlaps that of the discipline of rangeland management. Reviewing the history of the range should not be a parochial exercise, but should have a wider generic application to the history of the discipline. The history of research at Jornada has six often overlapping and evolving themes: classic range management, animal husbandry, ecology, range improvement, interdisciplinary sciences, and ecosystem science.

}, url = {/files/bibliography/488.pdf}, author = {Kris Havstad and W. H. Schlesinger}, editor = {J.R. Barrow and McArthur, E. Durant and R. E. Sosebee and R. J. Tausch} } @proceedings {51338, title = {Research in the Jornada Basin of southern New Mexico: A field tour}, volume = {General Technical Report INT-GTR-338}, year = {1996}, month = {May 23-25, 1995}, pages = {269-275}, publisher = {USDA Forest Service, Intermountain Research Station, Gen. Tech. Rep. INT-GTR-338}, address = {Las Cruces, NM}, abstract = {

During the Ninth Wildland Shrub Symposium in Las Cruces, New Mexico, May 22-24,1995, a field trip took participants to the southern end of the Jornada del Muerto Basin, an area of intensive research in desert ecology and rangeland management throughout the 20th century. The tour highlighted some of the historical studies in grazing management as well as current interdisciplinary research projects involving dozens of scientists from many institutions. Cooperating institutions and agencies include the USDA Agricultural Research Service, New Mexico State Uni- versity, the National Science Foundation and the Environmental Protection Agency.

}, url = {/files/bibliography/487.pdf}, author = {Kris Havstad and Reldon F. Beck}, editor = {J.R. Barrow and McArthur, E. Durant and R. E. Sosebee and R. J. Tausch} } @conference {51343, title = {Relationships between rangeland soil quality, soil resilience, and soil erosion}, booktitle = {Soil and Water Conservation Society Conference, Soil Quality and Erosion Interaction}, year = {1996}, month = {July 7-10, 1996}, address = {Keystone, CO}, abstract = {The relationships between rangeland soil quality, soil resilience and soil erosion depend on several interacting factors: (1) landscape and climate characteristics, (2) current disturbance regime, and (3) recent and evolutionary disturbance history. These factors tend to be more variable across rangelands than across agricultural lands. There are at least four specific relationships between soil quality and soil erosion which involve soil resistance or soil resilience. The first is the historical resistance of the soil to past disturbances, which can serve as an indicator of soil quality. Secondly, the current resistance of the soil to disturbance is related to soil erosion potential. The third relationship is the current resilience of the system following soil erosion. Finally, soil erosion is z driver in the system which determines soil quality. This final relationship illustrates the need to view the system dynamically: soil erosion both reflects and affects soil quality. These dynamic relationships depend, in turn, on the characteristics of historic and current disturbance regimes. Both ecosystems and species tend to evolve in response to dominant disturbance regimes, such as fire, drought, and grazing. The resistance and/or resilience of the system will tend to be higher for disturbance regimes which share key characteristics with historic and evolutionary patterns.}, keywords = {rangeland, soil erosion, soil quality, soil resilience}, author = {Jeffrey E. Herrick and M.A. Weltz and G.E. Schuman and Reeder, J.D. and Simanton, J.R.} } @proceedings {51353, title = {Regional stability of an ERS/JERS-1 SAR classifier}, year = {1996}, note = {//NONE//INTERSITE//ProCite field[6]: In}, month = {May 19961996}, pages = {1093-1095}, address = {Lincoln, Nebraska, USA}, abstract = {The potential of combined ERS/JERS-1 SAR images for land cover classification was demonstrated for the Raco test site (Michigan) in recent papers and articles. Our goal is to develop a classification algorithm which is stable in terms of applicability in different geographical regions. Unlike optical remote sensing techniques, radar remote sensing can provide calibrated data where the image signal is solely determined by the physical (structural) and electrical properties of the targets on the Earth{\textquoteright}s surface and near subsurface. Hence, a classifier based on radar signatures of object classes should be applicable on new calibrated images without the need to train the classifier again.This article discusses the design and applicability of a classification algorithm, which is based on calibrated radar signatures measured from ERS-1 (C-band, vv polarized) and JERS-1 (L-band, hh polarized) SAR image data. The applicability is compared in two different test sites, Raco, Michigan and the Cedar Creek LTER site, Minnesota. It was found, that classes separate very well, when certain boundary conditions like comparable seasonality or soil moisture conditions are observed.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, intersite, proceeding, proceedings, remote sensing}, author = {Kellndorfer, J. and Dobson, M. C. and Ulaby, F. T.} } @article {JRN54983, title = {Remote sensing applications to hydrology: introduction}, journal = {Hydrological Sciences}, volume = {41}, year = {1996}, month = {08/1996}, pages = {429-431}, chapter = {429}, abstract = {

This is the first of a proposed series of Special Issues of Hydrological Sciences Journal meant to give state-of-the-art overviews of the sciences covered in the different Commissions and Committees of the International Association of Hydrological Sciences (IAHS). The International Committee for Remote Sensing and Data Transmission (ICRSDT) organized this first Special Issue to cover the current research in and operational applications of remote sensing technology in hydrology. The latter applications are becoming more important because remote sensing techniques have the ability: (a) to measure spatial, spectral and temporal information; and (b) to provide data on the state of the Earth{\textquoteright}s surface. It is also a rapidly changing domain with new sensors, platforms and application techniques being developed to give hydrologists new data and new views of the landscape with which to evaluate the Earth{\textquoteright}s surface
(Rango, 1994; Running etal., 1994). Remote sensing provides observations of changes in hydrological states and variables over both time and space that can be used to monitor hydrological conditions and changes.

}, url = {files/bibliography/Rango1996-06.pdf}, author = {Jerry Ritchie and A. Rango} } @article {51381, title = {Relationships between landforms, geomorphic processes, and plant communities on a watershed in the northern Chihuahuan Desert}, journal = {Landscape Ecology}, volume = {11}, number = {6}, year = {1996}, note = {//NMSU//LTER III//}, month = {1996}, pages = {351-362}, abstract = {

The close correlation of plant communities to landforms and geomorphic surfaces resulted from differences in the redistribution of water and organic matter between landforms in the northern Chihuahuan Desert. Biotic processes are limited by water and nitrogen, and the interactions between landforms, geomorphic processes, soils, and plant communities control the redistribution of these limiting resources within internally drained catchments. Geomorphic processes are regulated by the geologic structure and gross topographic relief of internally drained catchments over geological time scales. Land forming processes can be viewed as static at time scales of 10{\textquoteright}s to 100{\textquoteright}s of years, with individual landforms regulating geomorphic processes, namely erosion and deposition resulting from the horizontal redistribution of water within the catchment. The vegetation composition is a critical feedback, reinforcing the erosional or depositional geomorphic processes that dominate each landform. The Jornada Long-Term Ecological Research site may be one of the simplest cases in which to decipher the relationship between landforms, geomorphic processes and plant communities. However, these geomorphic processes are common to all internally drained catchments throughout the Basin and Range Province, and result in the development of characteristic landforms and associated vegetation communities. Although the patterns may be modified by differences in parent material, watershed size, and land use history -- erosional, depositional, and transportational landforms can still be identified. The sharpness of ecotones between plant communities on individual landforms is related to the degree to which landforms are linked through the flow of water and sediment. Sharp ecotones occurred at the transition from depositional to erosional landforms where little material was transferred and steep environmental gradients are maintained. Gradual ecotones occurred at the transition from erosional to depositional landforms where large quantities of material were transferred leading to the development of a gradual environmental gradient. The relationships between geomorphic processes and vegetation communities that we describe have important implications for understanding the desertification of grasslands throughout semi-arid regions of North America. disturbances such as grazing and climate change alter the composition of plant communities, thereby affecting the feedbacks to geomorphic processes, eventually changing drainage patterns and the spatial patterns of plant communities supported within the landscape.

}, keywords = {article, articles, deposition, desertification, ecotones, erosion, grassland, grazing, journal, journals, limiting resources, runoff, shrubland, water availability}, doi = { 10.1007/BF02447522 }, url = {files/bibliography/JRN00217.pdf}, author = {Steven M. Wondzell and Gary L. Cunningham and Bachelet Dominique} } @conference {51422, title = {Responses of plant assemblages to disturbance gradients in the northern Chihuahuan Desert}, booktitle = {Winter Meeting of the British Ecological Society}, year = {1995}, month = {December 19-21, }, pages = {71}, address = {University of Sheffield, GB}, abstract = {At three locations in the Chihuahuan Desert, domestic livestock-induced disturbance gradients extend outward from watering points. Soil is more compacted but less stable near the watering points. Plant species richness changes little along the gradient, but species diversity and plant biomass does increase dramaatically with distance from the watering point.}, keywords = {Chihuahuan Desert, disturbance gradients, plant assemblages, species diversity}, author = {A.G. de Soyza and Justin Van Zee and Walter G. Whitford and Jeffrey E. Herrick} } @proceedings {51394, title = {Rangeland research in the Chihuahuan Desert}, year = {1995}, month = {1995}, abstract = {

Three major classes of symbiotic fungi were identified in the roots of native grasses and shrubs on arid rangelands of the southwestern U.S. The first class is vesicular-arbuscular mycorrhizae, common to most higher plants. These fungi enhance nutrient and water uptake in plants. The second major class of symbiotic fungi are common soil or saprobic fungi. Because of their association with the host plant their capacity is enhanced to access nutrients from immobile inorganic and complex organic resources and supply them to the plant. One demonstrated benefit of a saprophytic seed-borne fungus, Alternaria alternata, was that it decomposed the seed capsule at germination and transferred nutrients to the germinating seedling, improving chances for survival and establishment. {\textquoteright}These fungi likely play a role in the management of carbon resources in the ecosystem. Third major class of fungi regularly associated with grass and shrub roots were Chytridiomycetes, a primitive aquatic fungus. These fungi appear to regulate the colonization by the other two fungal classes. These fungi, acting in concert with each other, enhance nutrient and water uptake of native plants. They directly affect survival ability and competitiveness of all plant species in arid rangelands. We are researching these fungi because we think that new technologies for rangeland revegetation of degraded areas will require the presence of these fungal classes for successful reestablishment and survival of native plant species.

}, keywords = {cattle growers{\textquoteright} short course, Chihuahuan Desert, rangeland, research}, url = {/files/bibliography/446.pdf}, author = {Kris Havstad and D.M. Anderson and J.R. Barrow and Richard E. Estell and E.L. Fredrickson and Gibbens, Robert P. and Jeffrey E. Herrick and Walter G. Whitford} } @proceedings {51395, title = {Reflections from nearly a century of rangeland research in the Jornada Basin}, year = {1995}, month = {May 23-25, 1995}, pages = {2}, abstract = {The 80-year record of rangeland research at the Jornada Experimental Range (JER) is representative of the history of the rangeland science discipline. The initial impetus from research was the rapid and obvious degradation of rangeland resources from misuse and drought from the late 1800{\textquoteright}s to the early part of the twentieth century. Original researchers designed pasture-scale studies to develop guidelines for seasonal stocking rates and methodologies for distributing grazing use. By the 1940{\textquoteright}s, observations on vegetation dynamics, particularly the encroachment of woody species, drove development of research efforts in range improvement techniques. By the 1970{\textquoteright}s, with rangeland management compromised by an increasingly regulated environment and a broadening of resource interests, the appropriateness of research on grazing management and forage improvement technologies was diminished. For the past 20 years rangeland research has been redirected to include more fundamental ecological investigations. The utility of the research had been questioned by various clientele. It is important that we translate this knowledge into usable technologies for monitoring existing conditions, remediation of degraded conditions,and adapting to new management conditions.}, keywords = {drought, Jornada Basin, misuse, rangeland research}, author = {Kris Havstad} } @article {51397, title = {Resource islands predict the distribution of heterotrophic bacteria in Chihuahuan Desert soils}, journal = {Applied and Environmental Microbiology}, volume = {61}, number = {5}, year = {1995}, note = {//NMSU, USDA//LTER-III//}, month = {1995}, pages = {1816-1821}, abstract = {

The resource island hypothesis predicts that soil resources such as nitrogen, phosphorus, and water will be distributed evenly in grasslands but have a patchy distribution focused around plants in shrublands. This hypothesis predicts that microorganism numbers will follow resources and be (i) evenly distributed in grasslands, (ii) concentrated around individual plants in shrublands, and (iii) higher where resources are higher when comparing the same vegetation type. This study enumerated total heterotrophic bacteria and a subset of these, the nitrogen-efficient guild (NEG), in three shrublands (playa fringe mesquite, tar bush, and creosote) and two grasslands (playa and bajada). Both heterotrophs and NEG members followed the distribution pattern predicted by the resource island hypothesis. There were no significant differences in heterotroph or NEG numbers comparing at-plant and interplant samples for both the playa and bajada grasslands. Furthermore, populations were generally higher in nutrient-rich playa grasslands than nutrient-poor bajada grasslands. In contrast, both heterotroph and NEG numbers were higher at shrubs than between shrubs in all three shrub sites. These results suggest that resource abundance in resource islands predicts the distribution of heterotrophic bacterial numbers in desert soils.

}, keywords = {article, articles, bacteria, heterotrophs, bacteria, nitrogen-efficient guild, bacteria, resource islands, grassland, bacteria, journal, journals, nutrient amendment, bacteria, resource island, bacteria, resource island, soil nutrients, shrubland, bacteria}, url = {files/bibliography/JRN00195.pdf}, author = {Peter Herman and Kerri R. Provencio and Herrera-Matos, Johannie and Ruben Torrez} } @conference {51400, title = {Rethinking remediation technologies for desertified landscapes}, booktitle = {Society for Ecology Restoration Meeting}, year = {1995}, month = {September 14-16,}, pages = {105}, address = {University of Washington, Seattle, WA}, abstract = {

Shrub-dominated communities have replaced native grasslands throughout much of the arid Southwest. Past attempts to reestablish native grasslands or to revegetate with exotic grasses have largely failed or have resulted in further degradation. These attempts failed in spite of large energy inputs such as rootplowing, fertilization, and herbicides. Large-scale surface disturbances associated with these approaches may also disrupt soil and cultural resources. A recently initiated rangeland restoration research program at the USDA-ARS Jornada Experimental Range is based on the following premises: (1) biological integrity of both above- and below-ground systems, in addition to the short-term establishment of desired species, is necessary to buffer against future disturbances, (2) resource redistribution over time at the community and landscape levels plays an important role in both desertification and restoration processes, (3) restoration efforts should focus on fertile sites best suited for reestablishment of the native community, and (4) planting technologies should be based on readily available "natural" dispersal systems. Current and planned research at the Jornada includes work on the role of shrub rooting patterns and soil biota (e.g., mycorrhizae, ants, and termites) in restoration, the use of animals and water as potential dispersal agents of propagules, the use of grazing animals as remediation tools, and adaptation of indigenous agricultural practices.

}, keywords = {desertified landscapes, remediation technologies, Southwest}, url = {files/bibliography/95-SocforEcolRest-Herrick.pdf}, author = {Jeffrey E. Herrick and Kris Havstad and E.L. Fredrickson} } @booklet {51403, title = {Range Management Principles and Practices, 2nd Edition}, year = {1995}, month = {1995}, publisher = {Prentice Hall}, address = {Englewood Cliffs, NJ}, keywords = {practices, principles, range management}, author = {Jerry L. Holechek and Pieper, Rex D. and C.H. Herbel} } @proceedings {51412, title = {The role of microbes in resource management in arid ecosystems}, year = {1995}, month = {May 23-25, 1995}, pages = {22}, abstract = {

Fungal root endophytes similar to ones found in native grasses and shrubs in the arid southwest, also colonize alfalfa.\  Data show that these organisms regulate nutrient uptake in alfalfa by enhancing phosphorus uptake at low concentrations and restrict uptake at thigh concentrations.\  When external carbon was available the fungi were pathogenic to the host.\  Without external carbon, they were dependent upon the host and formed an endophytic association.\  Evidence suggests that host-microbe interactions play a major role in plant response to environmental stresses such as nutrient extremes, salinity, drought, and disease.\  It appears that these host-microbe associations have evolved to insure the management of vital resources for maintaining efficient healthy host plants for carbon production as a source of energy for the fungi.\  The conservative management of essential nutrients and water by the entophyte in arid ecosystems is crucial for survival of native plants.\  However, when arid ecosystems area converted to cropping systems, where nutrients and water are supplemented, the conservative regulation of nutrients and water by the fungi is likely to effect plant nutrition, disease expression, and response to environmental stress.

}, url = {files/bibliography/95-ShrubSymp-Barrow.pdf}, author = {McCaslin, B D. and J.R. Barrow} } @article {JRN54958, title = {Revisiting the Degree-Day Methood for Snowmelt Computations}, journal = {Water Resources Bulletin}, volume = {31}, year = {1995}, month = {08/1995}, pages = {657-669}, chapter = {657}, abstract = {

The simple, empirical degree-day approach for calculating snowmelt and runoff from mountain basins has been in use for more than 60 years. It is frequently suggested that the degree-day method be replaced by the more physically-based energy balance approach. The degree-day approach, however, maintains its popularity, applicability, and effectiveness. It is shown that the degree-day method is reliable for computing total snowmelt depths for periods of a week to the entire snowmelt season. It can also be used for daily snowmelt depths when utilized in connection with an adequate snowmelt runoff model for computing the basin runoff. The degree-day ratio is shown to vary seasonally as opposed to being constant as is often assumed. Additionally, in order to evaluate the degree-day ratio correctly; the changing snow cover extent in a basin during the snowmelt season must be taken into account. It is possible to combine the degree-day approach with a radiation component so that short time interval (\<24 hours) computations of snowmelt depth can be made. When snowmelt input is transformed to basin output (runoff) by a snowmelt runoff model, there is little difference between the degree-day approach and a radiation based approach. This is fortuitous because the physically-based energy balance models will not soon displace the degree-day methods because of their excessive data requirements. \ \ 

}, url = {files/bibliography/Rango1995-02.pdf}, author = {A. Rango and J. Martinec} } @conference {51435, title = {A role of endophytic fungi in regulating nutrients and energy in plants within a desert ecosystem}, booktitle = {International Symposium and Workshop on Desertification in Developed Countries: Why Can{\textquoteright}t We Control It?}, year = {1994}, month = {October 25-28, 1}, address = {Tucson, AZ}, abstract = {Roots of common native grasses and shrubs growing in arid regions of the southwestern United States were analyzed for symbiotic fungi. In addition to classical interfaces formed by vesicular-arbuscular mycorrhizae, many other types of fungal interfaces were observed. Fungal isolates from roots of native plants formed associations typical of ectendo mycorrhizae with root organ cultures of alfalfa (Medicago sativa L.), blue grama [Bouteloua gracilis (H.B.K) Lag.], alkali sacaton (Sporobolus airoides Torr.), and sideoats grama [Bouteloua curtipendula (Michx.) Torr.]. Infected alfalfa roots accumulated high concentrations of phosphorus butprevented translocation to leaves and stem, while noninfected roots allowed a five-fold increase of phosphorus in plant tops. This indicates that these fungi not only accumulate and store but regulate phosphorus transfer and possibly other essential nutrients and energy sources within the plant. Fungi associated with germinating seed of foaming saltbush [Atriplex canescens (Pursh) Nutt .] were also shown to degrade cellulose of the utricle and transfer carbon to the germinating seedling, which enhanced germination, vigor, and establishment. A hypothesis was developed to explain how endophytic fungi affect survival of native plants and the nutrition of cultivated crops growing in arid regions. An understanding of how these fungi affect native plant communities would be valuable in the management of desert areas.}, author = {J.R. Barrow} } @article {51438, title = {Relationship of tarbush leaf surface secondary chemistry to livestock herbivory}, journal = {Journal of Range Management}, volume = {47}, year = {1994}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {1994}, pages = {424-428}, abstract = {

Tarbush (Flourensia cernua DC.) is an abundant shrub native to the Chihuahuan desert. Limited use as a forage by ruminants has been observed. The objective of this studey was to eexamine the leaf surface chemistyr of tarbush inrelation to degree of use by ruminants. Mature tarbush leaves were collected on 2 sites during 2 periods approximately 2 weeks apart from plants exhibiting either high (\>45\%) or low (\<10\%) use when browsed by cattle, sheep, and goats confined to a small area (5 plants per use category for each site/period combination). A greater (P\<0.05) concentration of epicuticular wax was detected on the leaf surface of plants used to a lower degree. Epicuticular wax concentration was 8.2 and 10.3\% of the leaf dry matter for high and low used plants, repectively. Several leaf surface compounds were related to period, while site and degree of use were seldom related to individual mon- and sesquiterpenes measure in this study. Camphene and 10 unidentified compounds differed between periods (P 0.10). Two unidentified compounds were related to site (P \< 0.10) and 2 others were related to use (P\<.0.10). In summary, individual leaf surface compounds on tarbush do not appear to greatly affect degree of us of tarbush by livestock, but collectively ( based on epicuticular wax data), these compunds may influence the diet selected by browsing ruminants.

}, keywords = {Epicuticular wax, herbivores, Leaves, livestock, monoterpenes, Plant biochemistry, plants, shrubs, terpenes, terpenoids}, doi = {10.2307/4002991 }, url = {/files/bibliography/418.pdf}, author = {Richard E. Estell and E.L. Fredrickson and D.M. Anderson and W. Mueller and M.D. Remmenga} } @article {51445, title = {Root systems of desert plants}, journal = {Sonorensis}, volume = {14}, number = {1}, year = {1994}, month = {1994}, pages = {4,5 \&19}, abstract = {

We are all familiar with the above-ground parts of desert plants. While we may admire and photograph the pretty flowers or unusual plant forms that we can readily see, we seldom think of a major portion of the plant, the root system, which is concealed within the soil. Roots are very important to a plane because they not only anchor the plant in place but also are the means by which the plant acquires water and nutrients (nitrogen, phosphorus, potassium and other elements essential to growth). In low rainfall desert environments, water is often the most limiting factor for plant growth, and root systems of desert plants are often shaped to maximize the uptake of this vital element. Quite often, the weight of the root system is equal to or greater than the weight of the above-ground portion of the plant. A knowledge of the morphology or form of root systems is very helpful in understanding the ecology and interactions of the diversity of plant species found in desert environments.

}, url = {/files/bibliography/423.pdf}, author = {Gibbens, Robert P.} } @inbook {51449, title = {Rangeland cover types of the Southwestern Region: Creosotebush-Tarbush (SRM 508)}, booktitle = {Rangeland Cover Types of the United States}, year = {1994}, month = {1994}, pages = {67-68}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Denver, CO}, keywords = {cover types, creosotebush, rangeland, southwestern region, tarbush}, author = {C.H. Herbel}, editor = {Shiflet, T.N.} } @inbook {51451, title = {Rangeland cover types of the southwestern region: Introduction (SRM 500)}, booktitle = {Rangeland Cover Types of the United States}, year = {1994}, month = {1994}, pages = {61}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Denver, CO}, keywords = {cover types, introduction, rangeland, southwestern region}, author = {C.H. Herbel}, editor = {Shiflet, T.N.} } @conference {51464, title = {Rescuing at-risk data on the Jornada Experimental Range}, booktitle = {International Symposium and Workshop on Desertification in Developed Countries: Why Can{\textquoteright}t We Control It?}, year = {1994}, month = {10/1994}, address = {Tucson, AZ}, abstract = {

The Jornada Experimental Range is an Agricultural Research Service site consisting of 78,266 hectares, about 37 km north of Las Cruces, New Mexico, in the northern Chihuahuan Desert. The site is contiguous to the 25,900-hactare, New Mexico State University ranch. The Jornada Experimental Range is a prime research site for investigating the processes leading to desertification of semiarid grasslands and the changes in ecosystem properties that accompany desertification. Key ecosystem changes involve the replacement of grassland by creosotebush and mesquite shrub populations. Data related to soil, vegetation, precipitation, and livestock have been collected on the Jornada Experimental Range almost continuously from 1915 to the present. Although some of the data collected are now archived in digital format, either as a spreadsheet or geographic information system data layer, a great deal of the data is maintained in the original hardcopy format and is in serious danger of being lost due to deterioration. The Jornada Experimental Range, in conjunction with the New Mexico State University Physical Science Laboratory and the Consortium for International Earth Science Information Network (OESIN), has embarked on a pilot project to demonstrate the feasibility of converting the original hardcopy data into a digitized format and examining means of visualizing the digitized data in a way that enhances data usage by researchers. This paper addresses the design of the "data rescue" pilot project, describes the technology and methodology being used to digitize the hardcopy data, and describes "lessons learned" to date. Techniques being considered to visualize the digitized data will also be discussed.

}, keywords = {at risk, converting, data, digitized format, Jornada Experimental Range, techniques}, author = {Wallace, W. and Kris Havstad} } @mastersthesis {51471, title = {Response potential of three perennial desert grasses to various disturbances}, year = {1993}, note = {//NMSU//NONE, LTER//}, month = {1993}, pages = {94}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = { Increasing desertification of the northern Chihuahuan semidesert grasslands is linked, in part, with the decline or disappearance of perennial grasses. While vegetational changes have been well documented since the early 1900{\textquoteright}s, no clear cause for these changes has been determined. Although many disturbances have been linked to these changes, this study focuses only on grazing, microsite, and competition effects. By measuring the growth potential, establishment potential, and germination rates of Bouteloua eriopoda, and Sporobolus flexuosus, and Aristida wrightii, the study provided insights into potential response to these disturbances. In these dominant perennial grasses, grazing effects were measured in three major ways. A descriptive survey assessed differences between plants and populations with a history of livestock grazing and those without. Secondly, a clipping experiment measured regrowth potential in response to biomass removal from selected plants within these areas. Finally, differences in clonal spread in Bouteloua eriopoda were measured in grazed and ungrazed locations. In all three species, microsite effects were assessed through the survivorship and growth of clonal transplants planted into open and vegetated patches within shrubland and grassland communities. For competition effects, survivorship and growth responses were measured for the three species growing together in pots that were either in full sunlight or shade. In these studies, growth and establishment potential was measured by assessing plant height, plant size, stolon length, number of tillers or stolons, number of nodes, and flowering seed production. Germination rates were determined in a lab study, using seeds of the three grass species. Results indicated there were some significant grazing effects for the variables studied in some of the species. However, there was no significant effect of grazing history on response to clipping for any of the study species. Clonal spread was significantly different between sites and treatments in Bouteloua eriopoda. Survivorship was low for the clonal transplants. However, two of the three grass species had a higher survivorship within the vegetated microsite patches. In contrast, in the greenhouse experiment, the transplants that were in full sunlight had more tillers and increased height than those in the shade. Aristida wrightii had the highest seed production and germination rate.}, keywords = {Aristida, germination, Aristida, grazing, Bouteloua, germination, Bouteloua, grazing, dissertation, dissertations, germination, grass, germination, Sporobolus, grass, Aristida, grass, grazing, grass, Sporobolus, grass,Bouteloua, grass,germination, grassland, germination, grassland, grazing, Sporobolus,clipping effects, theses, thesis}, author = {Beres, Lisa Ann} } @article {51474, title = {Range condition influences on Chihuahuan desert cattle and jackrabbit diets}, journal = {Journal of Range Management}, volume = {46}, number = {4}, year = {1993}, note = {//NMSU//NONE//}, month = {1993}, pages = {296-301}, abstract = {Knowledge of comparative diet selection by cattle and black-tailed jackrabbits (Lepus californicus) would permit better estimation of grazing capacity on Chihuahuan desert ranges. Cattle and black-tailed jackrabbit diets were evaluated seasonally on good and fair condition ranges over a 2-year period. Fecal samples analyzed by the microhisotological technique were used to determine diets of both animals. Key forage species in cattle diets were dropseeds (Sporobolus sp.), black grama (Bouteloua eriopoda Torr.), leatherweed croton (Croton pottsii Lam.), and bush muhly (Muhlenbergia porteri Scribn.). Key forage species in jackrabbit diets were honey mesquite (Prosopis glandulosa Torr.), cactus (Opuntia sp.), dropseed, broom snakeweed (Gutierrezia sarothrae Pursh.), and black grama. Over diet botanical composition data showed cattle consumed 58\% grass compared to 22\% for jackrabbits (P<0.05). Forb consumption was similar between the 2 animals and averaged about 31\%. Shrub consumption averaged 47\% and 12\% for jackrabbits and cattle, respectively (P<0.05). Range condition did not influence total grass consumption by either animal. Both animals, however, had lower forb and higher shrub consumption on fair compared to good condition range. Overall dietary overlaps between jackrabbits and cattle were 40 and 42\% on good and fair condition ranges, respectively. Poisonous plants contributed up to 14 and 36\% of cattle and jackrabbit diets, respectively. Data from this study show little forage competitions occurs between cattle and jackrabbits when stocking rates and jackrabbit numbers are moderate. Several plants poisonous and unpalatable to cattle were important jackrabbit foods. These plants were more prevalent on the fair compared to the good condition rage.}, keywords = {article, articles, cattle, diet, food habits, cattle, food habits, Lepus, grazing management, cattle, grazing management, Lepus, history, grazing, journal, journals, lagomorph, diet, lagomorph, Lepus, diet, Lepus,diet, toxicity, cattle, toxicity, Lepus}, author = {Alipayou Daniel and Jerry L. Holechek and Valdez, Raul and Tembo, Ackim and Lewis Saiwana and Rusco, Michael and Manual Cardenas} } @article {51478, title = {Reflectance of vegetation and soil in Chihuahuan desert plant communities from ground radiometry using SPOT wavebands}, journal = {Remote Sensing of Environment}, volume = {46}, year = {1993}, note = {//USDA, NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1993}, pages = {291-304}, abstract = {

The spatially averaged reflectance of a partially vegetated land surface can be modeled as an area-weighted mixture of the reflectances of different components or classes of objects (plants, shadow) of the background (soil, grass). We sampled the spectral reflectance of the shaded and unshaded components of Chihuahuan desert plant communities (shrubs, soil, subshrubs, and perennial grasses) in the SPOT wavebands using a hand-held radiometer. WE examined the mean reflectance differences between components to evaluate their spectral separability. Shrub canopy and shaded components have similar reflectance in the visible wavebands. However, in the near-infrared band, which is strongly scattered by green plant canopies, the shaded canopy and shaded background components were similar to each other and lower than either sunlit background or sunlit canopy. When reflectance measurements were transformed to normalized ratio (NDVI, SAVI) and orthogonal green vegetation indices, the shaded and sunlit portions of each component (canopy and soil) were similar, but the shaded components were intermediate between their sunlit counterparts. Different soil types and plant species with different life forms (e.g., shrubs, grasses) and phenologies exhibited different reflectance characteristics. However, the broadband reflectances of the three dominant shrub species were similar at the end of the growing season, in spite of their differences in morphology.

}, keywords = {article, articles, Bouteloua, remote sensing, Flourensia, remote sensing, journal, journals, Larrea, remote sensing, model, landscape, Li-strahler, model, Li-strahler, Prosopis, remote sensing, radiometry, remote sensing, Bouteloua, remote sensing, Flourensia, remote sensing, Larrea, remote sensing, Prosopis, remote sensing, soil reflectance, remote sensing, soils, remote sensing, vegetation reflectance, soil, remote sensing}, doi = {10.1016/0034-4257(93)90049-4}, url = {files/bibliography/JRN00171.pdf}, author = {Janet Franklin and J. Duncan and Turner, Debra L.} } @article {51489, title = {Rabbit herbivory and its effect on cladode, flower, and fruit production of Opuntia violacea var macrocentra (Cactaceae) in the northern Chihuahuan Desert, New Mexico}, journal = {The Southwestern Naturalist}, volume = {38}, number = {4}, year = {1993}, note = {//NMSU//LTER II//}, month = {1993}, pages = {309-315}, abstract = {

We studied the timing and effect of black-tailed jackrabbit and desert cottontail herbivory on a platyopuntia species, Opuntia violacea var macrocentra at a site on the Jornada del Muerto, 35 km north of Las Cruces, New Mexico in the northern Chihuahuan Desert. Total monthly fecal pellet dry mass collected around the base of individual opuntias over 15 months indicates that both rabbit species exhibit a seasonal preference for this opuntia with the greatest grazing pressure evident during dry seasons or when little annual or new growth of other perennial plants is present. Neither rabbit species appears to graze small opuntias possessing less than three cladodes. They also appear to avoid grazing new cladodes, since more than 80\% of the cladodes produced in May 1990 survived for six months. The proportion of individual opuntias grazed increases with increasing cladode number size class as does the mean fecal-pellet dry mass collected around the base of individual opuntias. Spinescence did not affect grazing intensity over the 15-month study period. Instead, plant size and grazing history appear to be the most important determinants of grazing intensity. Although statistically not significant, there is a trend on our data which suggests that above-average rabbit hebivory may negatively affect cladode, flower and fruit production in intermediate opuntia size-classes only. For individuals with either very few or very many cladodes these parameters appear unaffected by rabbit herbivory. However, the strongly-skewed size-class frequency distribution indicates that recruitment of juvenile opuntias into the population is little affected by rabbit herbivory.

}, keywords = {article, articles, Cactaceae, Opuntia, herbivory, lagomorph, journal, journals, lagomorph, herbivory, lagomorph,Lepus, herbivory, lagomorph,Sylvilagus,herbivory, Opuntia, herbivory, Opuntia,phenology, phenology, herbivory, rabbit, SEE }, doi = {10.2307/3671608}, url = {files/bibliography/JRN00170.pdf}, author = {Hoffman, M. T. and Craig D. James and G. I. H. Kerley and Walter G. Whitford} } @conference {51492, title = {Role of grazing in shrub invasion and desertification}, booktitle = {Texas Tech University, Research Highlights: Noxious Brush and Weed Control, Range and Wildlife Management}, volume = {24}, year = {1993}, month = {1993}, pages = {22}, abstract = {Desertification is a serious problem in vast areas of the U.S. and worldwide. Studies of shrub invasion and desertification in the Chihuahuan Desert of New Mexico generally accept that livestock can promote shrub invasion by preferentially grazing related to toxicosis. Because they remain ungrazed, shrubs invade and outcompete desirable grasses. Shrub invasion starts a cycle of erosion and nutrient loss between shrubs, which furthers the decline of grasses and promotes aridity. We started a project to study the feasibility of manipulating the toxicity of shrubs and dietary preferences of sheep to reduce shrub invasion. In our first experiment, carried out at the USDA Jornada Experimental Range, we studied the variability of tarbush intake among individuals in a flock of ewes. A flock of 32 polypay ewe lambs were moved daily through five 0.3-acre paddocks for a total of 10 days. Paddocks were similar and bad abundant by the bite-count technique. Blood was drawn from each ewe at the beginning and end of the experiment to assess toxicity effects. Preliminary observations indicate that sheep strongly preferred grasses to tarbush. Tarbush intake was low, even after grasses had been depleted considerably. Not toxicity effects were detected by blood analysis. Animals that exhibited the lowest and highest intake of tarbush will be tested later in controlled conditions to assess individual variation in ability to tolerate (or detoxify) tarbush.}, url = {/files/bibliography/407.pdf}, author = {Laca, E.A. and Launchbaugh, K.L. and E.L. Fredrickson and Richard E. Estell and Ksiksi, T.} } @article {51515, title = {Recovery and germination of gelatin-encapsulated seeds fed to cattle}, journal = {Journal of Arid Environments}, volume = {22}, year = {1992}, note = {Full Article from Journal of Arid Environments posted on this website with permission from Elsevier. http://www.sciencedirect.com/science/journal/01401963}, month = {1992}, pages = {395-399}, abstract = {

Artificial reseeding of marginal farmlands, wildlands or rangelands by mechanical mens is expensive and often unsuccessful. This study conducted to determinethe recovery and germinability of seeds of the southwestern USA rangeland forages fed to cattle. Seed of fourwing saltbush (Atriplex canescens), alkali sacaton (Sporobolus airoides), blue panicgrass (panicum antidotale), and sideoats grama (Bouteloua curtipendula) were administered in gelatin capsules to seers maintained on a moderate-qulaity alfalfa (medicago sative) diet. Approximately 95\% of the recovered seed passed through the steers wihink 72 h after dosing, but recovery varied among species. Total recovery was 9.5, 46.4, 61.8, and 0\% for fourwing saltbush, alkali sacaton, blue panicgrass adn sideoats grama, respectively. Fourwing saltbush, blue panicgrass, and alkali sacaton retained viability and germinated in the fecal material. Germination of seeds recovered 48 h post ingestion was 14.8, 50.1 and 41.4\% for fourwing saltbush, alkali sacaton and blue panicgrass, use of gelatin capsules would be an effective method for easily feeding known quantities of seeds to livestock in small herds and could be incorporated with other common and necessary livestock handling practices.

}, doi = {10.1016/S0140-1963(18)30582-2}, url = {/files/bibliography/381.pdf}, author = {J.R. Barrow and Kris Havstad} } @conference {51519, title = {Role of secondary chemistry of tarbush in herbivory by livestock}, booktitle = {Annual Meeting, Society for Range Management}, year = {1992}, month = {1992}, pages = {P096}, abstract = {

Tarbush (Flourensia cemua) is an abundant shrub in the Chihuahuan desert which is used to a limited degree by ruminants. Related current research has demonstrated differential livestock use within this species. We hypothesize that grazing ruminants express selection preference for individual tarbush plants based upon leaf surface concentrations of epicuticular waxes and terpenoids. The objective of this study was to examine the leaf surface chemistry of tarbush in relation to degree of use by ruminants. Samples were collected in the mature leaf stage on 2 sites from plants exhibiting either high (\>40\%) or low (\<5\%) degree of use when browsed by cattle, sheep, and goats confined to a small area (10 plants per use category per site). Use was estimated visually and approximately 50 g of leaves from each plant were removed and placed on dry ice. Epicuticular waxes were determined with a gravimetric procedure, using a chloroform extraction of whole leaves. Leaves were also extracted in ethanol for mono- and sesquiterpenoid analysis with gas chromotography/mass spectrophotometry. The chloroform extraction revealed a greater concentration of epicuticular wax on the leaf surface of plants which were used to a lower degree (P \< 0.02). Epicuticular wax concentration was 9.5 and 12.0\% (organic matter basis) for high and low use plants, respectively. Data will be presented on surface terpenoid concentrations and their relationship to degree of use of tarbush by grazing ruminants. Information obtained on surface chemistry might be exploited to enhance use of tarbush as a forage.

}, author = {Richard E. Estell and E.L. Fredrickson and Kris Havstad and D.M. Anderson} } @article {51524, title = {Recent rates of mesquite establishment in the northern Chihuahuan Desert}, journal = {Journal of Range Management}, volume = {45}, year = {1992}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {1992}, pages = {585-588}, abstract = {

Honey mesquite (Prosopis glandulosa Torr. var. glandulosa) populations continue to expand and become more dense, even on areas once "successfully" treated either with herbicides or by bulldozing in southern New Mexico.\  Areas treated from 1958-1964 for mesquite control on the USDA-ARS Jornada Experimental Range and the New Mexico State University College Ranch were sampled to determine mesquite density changes.\  On herbicide treated areas sampled in 1976 and again in 1988, mesquite densities increased 10\%\  to 128\% and had densities from 67 to 494 plants/ha.\  Two areas\ treated by either bulldozing or fenuron in 1959-60, and with original kills near 100\%, had an average density of 377 plants.ha by 1988, with an establishment rate of 13.5 plants/ha/year.\  On the College Ranch, mesquite densities increased 11\%, from 130 (1982) to 147 (1988) plants/ha.\  Only 19\% of a cohort of mesquite seedlings which germinated in 1989 were still alive in May 1990.\  Even though only a small percentage of the mesquite that germinated survived into the second year, this is enough to change former grasslands into mesquite-dominated rangelands.\ 

}, keywords = {arid rangelands, desert grasslands, prosopis glandulosa, seedling establishment, shrub invasion}, url = {/files/bibliography/385.pdf}, author = {Gibbens, Robert P. and Reldon F. Beck and R.P. McNeely and C.H. Herbel} } @conference {51525, title = {Root systems of some Chihuahuan Desert plants}, booktitle = {Annual Meeting, Society for Range Management}, year = {1992}, month = {1992}, pages = {43}, abstract = {Root systems of shrubs, grasses and forbs were excavated in plant communities occurring on relatively deep, fine sandy and day loam soils on the Jornada Experimental Range in southern New Mexico. Root systems of grasses extended to depths of about 1 in and did not penetrate far into the well developed calcic horizons. Perennial forb root systems extended to depths of 1.6 m and were well developed in calcic layers. Shrub root systems, including tarbush (Flourensiacernua DC), fourwing saltbush [Atriplex canescens (Pursh) Nutt.], wolfberry (Lycium berlandieri Dunal), and winterfat [Ceratoides lanata (Pursh) J.T.Howell], besides extending laterally 1 to 5 m, grew through the calcic horizons and extended to depths of 3 to >5 m. Roots of crucifixion thorn (Koeberlinia spinosa Zucc.) penetrated >S m but the unusual feature was large roots branching off at a depth of 3.5 m and growing vertically or obliquely upward before branching extensively between depths of .8 to .1 m. The extensive root systems of shrubs is one reason they have been so successful in this desert environment.}, keywords = {Chihuahuan Desert plants, descriptions, root systems}, author = {Gibbens, Robert P. and J.M. Lenz} } @article {51588, title = {Range condition analysis: comparison of 2 methods in southern New Mexico desert grasslands}, journal = {Journal of Range Management}, volume = {44}, number = {4}, year = {1991}, note = {//NMSU//NONE//}, month = {1991}, pages = {374-378}, abstract = {Interest in evaluation theoretical considerations in traditional methods of determining range condition have increased recently with application of different analytical techniques. In this study, the traditional quantitative climax approach was compared to a cluster analysis method on range sites in desert grassland in southern New Mexico. Both methods identified 3 classes that corresponded to successional stages or range condition classes. The cluster analysis approach provided a more precise procedure than the quantitative climax approach, as evaluated by multiple discriminate analysis. However, the cluster analysis is a much more complex analytical procedure than the quantitative climax approach, and may be limited for management purposes.}, keywords = {article, articles, grassland, cluster analysis, grassland, secondary succession, grassland, spatial variation, journal, journals, productivity, range condition, range condition, range management, rangeland, cluster analysis, rangeland, secondary succession, rangeland, spatial variation, rangeland,condition classification, succession, grassland, technique, cluster procedure, technique, range condition classification}, author = {Pamo, E. Tedonkeng and Pieper, Rex D. and Reldon F. Beck} } @article {51600, title = {Runoff and erosion following mechanical and chemical control of creosotebush (Larrea tridentata) }, journal = {Weed Technology}, volume = {5}, year = {1991}, month = {1991}, pages = {48-53}, abstract = {

Runoff and sediment yield wer monitored from 1983 through 1986 on a range site dominated by creosotebush. The site was rootplowed and seeded, treated with tebuthiuron at 36 kg ai ha -1, or left untreated. Runoff from rootplowed and herbicide-treated plots was no different from untreated plots for 1 yr, but sedimetn yield from treated plots was lower than that from the untreated plots. Rootplowing and seeding increased sediment yield in the second year (1984), whereas treating with herbicide decreased sediment yield. Runoff and sediment yield during 1985 and 1986 were greatest from the untreated areas and least from the rootplowed and herbicide-treated areas. Total cover was nearly the same for each treatment. The untreated plots had 13\% shrub cover, the others had none. Between shrubs in untreated plots, bare ground occupied large interconnected areas that contributed to the higher runoff and erosion rates.

}, keywords = {Chihuahuan Desert, phytomass, rainfall, root plow, sediment yield, water stage}, url = {/files/bibliography/376.pdf}, author = {Wood, M. Karl and E.L. Garcia and J.M. Tromble} } @proceedings {51605, title = {Rainfall infiltration and loss on a bajada in the Chihuahuan Desert, New Mexico}, year = {1990}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//updated 11/11/2009: abstract; 11/23/2009: author, editor, proceedings title, call $\#$.ProCite field[6]: In}, month = {July 30 - August}, pages = {349-355}, publisher = {American Society of Civil Engineers}, address = {San Diego, CA}, abstract = {

Watershed from runoff from thunderstorms is heavily dependent upon the rainfall intensity and the infiltration or loss rate of the watershed. Although techniques are available for determining infiltration rates of soils, these techniques are inadequate when dealing with vegetation-soil complexes found in arid and semi-arid environments. A more representative technique is on-site measurements of runoff from natural and/or simulated rainfall. Analysis from natural and simulated rainfall-runoff plots located on a bajada (alluvial fan) northeast of Las Cruces , New Mexico, indicate that the sparse desert vegetation does not have a significant effect on runoff depth (natural plots), vegetation has a slight but significant effect on infiltration rate (simulator plots), and a seasonal effect on infiltration losses.

}, keywords = {abstract, abstracts, bajada,hydrology, conference, conference proceedings, conferences, hydrology, infiltration, proceeding, proceedings, rainfall, infiltration}, author = {S. M. Bolton and Timothy J. Ward and Walter G. Whitford}, editor = {French, Richard H.} } @proceedings {51606, title = {Rainfall simulation studies of nutrient export from watersheds in Arizona and New Mexico}, year = {1990}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//updated 11/11/2009: full author names, proceedings title, , abstract, workform [request copy 11/11/09 online from NMSU Library-ILLiad]ProCite field[6]: In}, month = {1990}, publisher = {American Society of Civil Engineers}, abstract = {Data from rainfall simulation experiments conducted in Arizona and New Mexico were used to identify relationships between total suspended sediment (TSS) concentrations (kg/ha/mm of runoff) in runoff and concentrations (kg/ha/mm of runoff) of total phosphorus (TP) and total volatile suspended sediment (TVSS). Lumping data from five vegetation types yielded the following relationship for total phosphorus: TP = 0.0013* (TSS)** 0.83 with a linear correlation coefficient, r = 0.77. The relationship for total volatile suspended sediment was TVSS = 0.274* (TSS)** 0.72 (r = 0.91). These relationships were validated using data from other experiments and ephemeral channel flow.}, keywords = {book, books, chapter, chapters, hydrology ,nutrient export, nutrient, export, rainfall simulation, nutrient export, report, reports}, author = {S. M. Bolton and Timothy J. Ward and R. A. Cole}, editor = {R. Riggins and Jones, E. B. and Ranvir Singh and Rechard, P. (eds.)} } @conference {51613, title = {Recent rates of mesquite (Prosopis glandulosa Torr.) establishment in the northern Chihuahuan Desert}, booktitle = {43rd Annual Meeting, Society for Range Management}, year = {1990}, month = {1990}, pages = {191}, address = {Reno, NV}, author = {Gibbens, Robert P. and Reldon F. Beck and R.P. McNeely} } @inbook {51615, title = {Rehabilitation Techniques, Part I}, series = {The Improvement of Tropical \& Subtropical Rangelands}, year = {1990}, month = {1990}, pages = {139-185}, publisher = {National Academies Press}, organization = {National Academies Press}, address = {Washington, D.C.}, author = {C.H. Herbel}, editor = {National Research Council} } @article {51633, title = {Range conditions from an ecological perspective: modifications to recognize multiple use objectives}, journal = {Journal of Range Management}, volume = {43}, year = {1990}, note = {//??//NONE//}, month = {1990}, pages = {550-552}, keywords = {article, articles, journal, journals, range condition, resource values, secondary succession, seral stages}, author = {Pieper, Rex D. and Reldon F. Beck} } @mastersthesis {51635, title = {Range condition effects of scaled quail in southcentral New Mexico}, year = {1990}, note = {//??//NONE//}, month = {1990}, pages = {114}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, keywords = {bird,Scaled quail, dissertation, dissertations, Scaled quail, theses, thesis}, author = {Lewis Saiwana} } @book {51652, title = {Root Systems}, series = {Physiological Plant Ecology}, year = {1989}, note = {//??//LTER II//Listed in LTER3 proposal as citing LTER2 support//ProCite field[6]: In}, month = {1989}, pages = {367-398}, publisher = {Chapman and Hall Publishers}, organization = {Chapman and Hall Publishers}, address = {New York}, abstract = {

Although root system studies are generally conceded to be important, the difficulties in such study are sufficiently daunting that root systems have received comparatively little attention in physiological ecology. The problems involve, in part, the sizable labor and time investment, the variability in root locations and activity, and the inadequacies of many root measures. The difficulties are often exacerbated for very fine roots and deep root systems. In spite of these difficultties, a judicious selection of experimental approaches, including indirect assessments, can yield meaningful results and can contribute significantly to an understanding of plant function in the field. Many new techniques have become available in the last few years. This chapter outlines a broad range of techniques for assessing root system structure and function in the field. Boehm (1979) has thoroughly described the classical, and still useful, root evaluation techniques. Emphasis here is, therefore, directed to newer techniques not covered to a great extent by Boehm (1979). This chapter treats methods as they relate primarily to the study of root systems in the field. Individuals working with root systems have displayed a certain proclivity to coin new terms for the ecological lexicon. In this chapter one encounters terms such as a {\textquoteright}hydropneumatic elutriation system{\textquoteright}, a {\textquoteright}microrhizotron{\textquoteright} and a {\textquoteright}perforon{\textquoteright}. Of course, we feel a certain obligation to define such terms but at the same time to employ more conventional English descriptors.

}, keywords = {book, books, chapter, chapters, report, reports, root systems}, url = {files/bibliography/JRN00104.pdf}, author = {Caldwell, M. M. and R. A. Virginia}, editor = {J. R. Ehleringer and Mooney, H. A. and Pearcy, R. W. and P. Rundel} } @article {51653, title = {The relationship between abiotic factors and the abundance patterns of soil microarthropods on a desert watershed}, journal = {Pedobiologia}, volume = {33}, number = {2}, year = {1989}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1989}, pages = {79-86}, abstract = {

A number of authors have reported the influence of abiotic parameters on the spatial and temporal distribution of soil microarthropods (REDDY, 1984; MALLOW et al., 1984; STREIT, 1982; ANDERSON \& HALL, 1977; USHER, 1976). It is clear from these studies that microarthropods respond differentially to the environmental factors. USHER (1976) and USHER et al.(1982) stressed the importance of the distributuion of food resources and soul moisture. SCHENKER (1984), working in a mixed deciduous forest soil, found few statisically significant correlations; although the relations between microarthropods and soil features seemed apparent. In deserts, the abiotic effects of climatic extremes of soil moisture and temperature are believed to drive many biotical processes taking place in the soil system (WALLWORK, 1982). The effect of these variables and organic matter on desert soil microfauna has been studied in different ways. SANTOS et al. (1987) reported highly significant correlations between mass of surface litter and density of microarthropods. STEINBERGER \& WHITFORD (1985) found correlations between total microarthropods and soil moisture but the the significance of these correlations depended upon site and season. Surveying a desert swale, STEINBERGER \& WHITFORD (1985) observed that, whereas overall microarthropod abundance was correlated with soil moisture, some species-populations were not. WALLWORK et al.(1984), working with simulated rainfall, showed that a continuous irrigation regime caused changes in the reproductive patterns of some species of oribatids, but not in others. WHITFORD et al. (1981) observed an increase in numbers and diversity of microarthropods in surface litter within one hour after artificial wetting; nevertheless, a subsequent decrease followed in the still moist litter. STEINBEGER et al. (1984) concluded that water, in the absence of an adequate supply of organic matter, does not stimulate population increase of the soil fauna. MCKAY et al. (1986) showed that soil temperature (or insolation) has a greater effect on overall microarthropod population densities than soil moisture. Thus most studies in deserts have focused on climatic variables and only marginally on soil properties. This study was designed to examine the relationships between abundance patterns of soil microarthropods and soil properties and climate in a northerm Chihuahuan Desert ecosystem.

}, keywords = {abiotic factors,soil microarthropod, article, articles, climate, microarthropod, journal, journals, microarthropod, abiotic factor, microarthropod, climate, microarthropod, distribution, microarthropod, soil properites, microarthropod,also SEE , soil microarthropod,abiotic factors, soil microarthropod,distribution}, url = {files/bibliography/89-Pedobiologia-Whitford.pdf}, author = {Cepeda, Jorge G. and Walter G. Whitford} } @book {51665, title = {Range Management Principles and Practices}, year = {1989}, month = {1989}, pages = {542 pp}, publisher = {Prentice-Hall Publishers Co.}, organization = {Prentice-Hall Publishers Co.}, address = {Englewood Cliffs, NJ}, url = {/files/bibliography/346.pdf}, author = {Jerry L. Holechek and Pieper, Rex D. and C.H. Herbel} } @article {51666, title = {A Review: Understanding sheep behaviour, a key to more efficient and profitable lamb and wool production}, journal = {SID Research Journal}, volume = {5}, year = {1989}, month = {1989}, pages = {26-33}, abstract = {

A knowledge of sheep behavior can help to improve production efficiency. Flocking instinct and social attachments provide methods to improve the efficiency of managing sheep through bonding to cattle to reduce loss to predation and minimize stress at weaning. Characteristics of sheep movement behavior have contributed to the design of efficient sheep-working facilities and management systems. Cattle, sheep and goats are complementary in transforming the range resource into red meat and fiber. Grazing behavior and diet learning are leading to improved forage utilization and range management. Periodic exposure of rams to ewes increases testes size, fertility and libido. Exposure of ewes, previously isolated from males, to rams during the transitional period between the non breeding and breeding season can initiate early breeding and fall lambs. Ewe lambs are shy breeders and should be mated separately from mature ewes. Orphan lambs can be fostered to ewes with extra milk utilizing odor transfer techniques resulting in higher and more efficient lamb production. Stress management can improve rate of gain following weaning and in feedlot lambs.

}, keywords = {behavior, management, production, sheep}, url = {/files/bibliography/347.pdf}, author = {Clarence V. Hulet} } @mastersthesis {51689, title = {Response of black grama grass, Bouteloua eriopoda, to water and nitrogen in a northern Chihuahuan Desert grassland}, year = {1989}, note = {//NMSU//LTER II//}, month = {1989}, pages = {53}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {

The response of Bouteloua eriopoda, black grama, to irrigation and nitrogen fertilization was examined to test the hypothesis that, in desert grasslands, nitrogen availability is greater than in adjacent shrublands. Tiller growth was greater in irrigated plots (P \< 0{\textperiodcentered}05) while nitrogen had no significant effect on growth (P \> 0{\textperiodcentered}05). Nitrogen induced early flowering but water had a greater effect during the various phenological stages. Water affected flowering, mortality, insect damage, and biomass production.

Nitrogen and nitrogen plus water reduced root length of the experimental plants (P \< 0{\textperiodcentered}05). The short and mat-like roots of fertilized plants may allow use of the small rainfall events more efficiently than the plants which received only irrigation (46 out of 61 precipitation events were \< 6 mm in size). There were no differences in the total biomass production of nitrogen-treated or water-nitrogen-treated subplots compared to controls. There was a higher nitrogen content of stems and leaves on plants from the irrigated-fertilized plots, but no significant differences among other treatments. Based on the large effects of irrigation in a third wet year (\> 300 mm year-1) and marginal nitrogen effects, we conclude that productivity in Chihuahuan Desert Bouteloua eriopoda grasslands is less nitrogen limited than that of the Larrea shrublands. Further, productivity in this perennial desert grassland appears to be closely linked to rainfall with no temporal lags due to nitrogen immobilization.

}, keywords = {Bouteloua,nitrogen, Bouteloua,nitrogen amendment, Bouteloua,simulated rainfall, dissertation, dissertations, grassland,nutrient amendment, nitrogen,grass, simulated rainfall,Bouteloua, theses, thesis}, author = {Stephens, Gracelet A. and Walter G. Whitford} } @article {51704, title = {Response of bonded and nonbonded sheep to the approach of a trained border collie}, journal = {Applied Animal Behavior Science}, volume = {21}, number = {3}, year = {1988}, note = {Reprinted with permission from Elsevier, Copyright {\textcopyright} 1988. (http://www.sciencedirect.com/science/journal/01681591)}, month = {1988}, pages = {251-257}, abstract = {

Intra- and interspecific association of cattle and bonded or nonbonded sheep was observed under free-ranging conditions preceding, during and following the approach of a trained border collie dog. A bonded sheep is one which consistently stays in close proximity to cattle as a result of a continuous close association between the two species, which began when the sheep was a young lamb. The dog treatment provided insight into the response of livestock to an aggressive, threatening canine. Sheep bonded to cattle remained together as one interspecific group when threatened by the dog. Interspecific space decreased and the sheep positioned themselves among the cattle and away from the dog. Cattle aggression, i.e. kicking and charging the dog, was only observed when the dog approached the heifers. Nonbonded sheep and cattle reacted as two distinctly independent intraspecific groups. The nonbonded sheep reduced their intraspecific space and moved away from the cattle when threatened by the dog. The protection that bonded sheep receive from cattle appears to result from the close association with the cattle, which poses a threat to predators.

}, doi = {10.1016/0168-1591(88)90114-1}, url = {/files/bibliography/325.pdf}, author = {D.M. Anderson and Clarence V. Hulet and Shupe, W. Larry and J. N. Smith and L. W. Murray} } @conference {51705, title = {Response of bonded and unbonded sheep to the approach of a trained border collie}, booktitle = {41st Annual Meeting, Society for Range Management}, year = {1988}, month = {1988}, pages = {187}, abstract = {Intra-and interspecific association of young cattle and yearling ewes bonded or nonbonded to cattle was observed under free-ranging conditions preceding, during and following the approach of a trained border collie dog. The dog treatment provided insight into the response of livestock to an aggressive, threatening canine. Sheep bonded to cattle remained together as one interspecific group when threatened by the dog. Interspecific space decreased and the sheep positioned themselves among the cattle and away from the dog. Bovine aggression, ie., kicking and bunting at the dog, was only observed when the dog approached the heifers. Nonbonded sheep and cattle reacted as two distinct intraspecific groups. The ovines reduced their intraspecific space and moved away from the bovines when threatened by the dog. The protection which bonded sheep receive from cattle appears to result from the close association with the cattle which pose a threat to predators.}, author = {D.M. Anderson and Clarence V. Hulet and Shupe, W. Larry and J. N. Smith} } @mastersthesis {51732, title = {Relationships between creosotebush productivity and associated foliage arthropod assemblages}, year = {1988}, note = {//NMSU//NONE, LTER//}, month = {1988}, pages = {159}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {I conducted field experiments to examine relationships between creosotebush (Larrea tridentata) foliage production and associated foliage arthropods. Chapter One presents the results of an experiment designed to assess the effects of increased nitrogen and water on creosotebush foliage arthropods. Nitrogen fertilizer and irrigation treatments were applied to creosotebush shrubs. Water with nitrogen, and nitrogen alone, increased foliage production, foliar nitrogen contents, and numbers of foliage arthropods. Water alone had less effect on foliage production, and no effect on foliar nitrogen or numbers of arthropods. Sap-sucking insects were the most abundant arthropods responding to increased foliage production and foliar nitrogen contents. The experiment presented in Chapter Two was designed to determine if phytophagous insects on creosotebush increase rates of plant to soil nitrogen flux from nutrient-rich shrubs. Foliage arthropod populations, and nitrogen in canopy throughfall and stemflow, were measured to assess nitrogen flux rates relative to arthropod densities on fertilized and unfertilized shrubs. Foliage arthropod densities and biomasses, and amounts of nitrogen in throughfall, were greater from fertilized shrubs. Nitrogen excreted by foliage arthropods accounted for about 20\% of the total nitrogen flux from unfertilized shrubs. I propose a model predicting foliage arthropods to enhance nitrogen availability to creosotebush shrubs. In Chapter Three, I tested the hypothesis that creosotebush shrubs growing in nutrient-rich micro-sites support more insects than shrubs growing in less productive sites. Shrubs from nutrient-rich sites had greater branch growth, flower production, and foliar nitrogen, than shrubs from less productive sites. Shrubs from nutrient-rich sites also supported greater densities of foliage arthropods. Shrub characteristics indicative of productivity covaried positively with foliage arthropod densities, and foliar resin concentrations covaried negatively with arthropod guilds. These findings are inconsistent with the theory that phytophagous insects are more successful on stressed host plants.}, keywords = {arthropod, foliage, dissertation, dissertations, Larrea, arthropods, Larrea, productivity, model, Larrea arthropods, nutrient amendment, nitrogen, nutrient amendment, water, rainfall simulation, theses, thesis, water amendment}, author = {David C. Lightfoot} } @article {51773, title = {Responses of Chihuahuan Desert herbaceous annuals to rainfall augmentation}, journal = {Journal of Arid Environments}, volume = {12}, year = {1987}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1987}, pages = {127-139}, abstract = {

Densities and biomass of annual herbaceous plants were compared on plots receiving supplemental water of 25 mm at 4-week intervals or 6.6mm per week, and plots receiving only natural rainfall. During the first summer, there were no significant differences in total biomass between treatments, but the density and biomass of two species, Astragalus tephrodes and Euphorbia micormera, were greater on the watered plots. Several spring annuals responded to supplemental water and by late spring (April) there were decreases in biomass on the watered plots, with the greatest decreases on the 6.3 mm per week plots. Few species of summer annuals responded to supplemental water during the second year, possibly as a result of smaller rain events and/or limitation of available nitrogen. Root shoot biomass ratios were between 0.15 and 0.25 for winter-spring annuals and 0.04 and 0.03 for summer annuals.

}, keywords = {annual plant, growth response, annual plant, rainfall simulation, annual plant,soil nutrient, article, articles, Astragalus, water response, Euphorbia, water response, journal, journals, rainfall simulation, rainfall simulation,annual plant response, water,also SEE }, doi = {10.1016/S0140-1963(18)31183-2}, url = {files/bibliography/JRN00059.pdf}, author = {Julio R. Gutierrez and Walter G. Whitford} } @article {51789, title = {The role of subterranean termites in the decomposition of above ground creosotebush litter}, journal = {Sociobiology}, volume = {13}, number = {3}, year = {1987}, note = {//NMSU//LTER I//}, month = {1987}, pages = {235-239}, abstract = {

We investigated the role of the termite Gnathamitermes tubiformans (Isoptera: Termitidae) in the breakdown of above ground creosotebush (Larrea tridentata) litter in the northern Chihuahuan Desert of New Mexico, USA. Comparison of decomposition rates of control plots with termite-excluded plots demonstrated that termites (and microarthropods) had no significant effect on mass loss. This species normally consumes other organic matter and only uses creosotebush litter when nothing else is available. This keystone species therefore plays a minor role in the breakdown of surface litter of the dominant shrub of the Chihuahuan Desert.

}, keywords = {article, articles, decomposition,termite, Gnathamitermes, journal, journals, Larrea, litter decomposition, termite,decomposition}, url = {files/bibliography/JRN00063.pdf}, author = {William P. MacKay and Solange Silva and S. J. Loring and Walter G. Whitford} } @proceedings {51812, title = {Regeneration of plants from two species of saltbush, Atriplex canescens and A. griffithsii}, year = {1986}, month = {1986}, pages = {178}, keywords = {A. griffithsii, Atriplex canescens, plants, regeneration, saltbush}, author = {J.R. Barrow} } @article {51862, title = {Rainfall and decomposition in the Chihuahuan desert}, journal = {Oecologia}, volume = {68}, year = {1986}, note = {//NMSU//LTER//}, month = {1986}, pages = {512-515}, abstract = {

We tested the hypothesis that rates of decomposition in a desert should be higher following single large rain events of 25 mm than evenly spaced 6 mm events and that supplemental rainfall should result in higher populations of soil biota. There were no significant differences in mass losses of creosotebush, Larrea tridentata, leaf litter on plots receiving water supplementation and no added water. On some sampling dates, there were higher mass losses in the 6 mm/week-1 treatment. Weekly rainfall produced higher coefficients of variation in mass losses than the other rainfall regimes. A single event pulse compared with weekly pulses of rainfall during the normal "dry" period resulted in no differences in mass losses. Microarthropods and nematodes exhibited numerical responses to supplemental rainfall but the litter microflora did not. These studies provide direct experimental evidence that the conventional wisdom linking decomposition to rainfall in deserts is wrong. The studies also suggest that the effects of litter fauna on surface litter decomposition are minimal; therefore, future studies should focus on activities of the microflora.

}, keywords = {article, articles, decomposition, litter microflora, decomposition, microarthropods, decomposition, nematodes, decomposition,rainfall, journal, journals, Larrea,decomposition, litter,decomposition, microarthropod,decomposition, microarthropod,rainfall simulation, precipitation,decomposition, rainfall simulation, decomposition, rainfall, SEE }, doi = {10.1007/BF00378764}, url = {files/bibliography/JRN00040.pdf}, author = {Walter G. Whitford and Yosef Steinberger and William P. MacKay and L. W. Parker and D. W. Freckman and J. A. Wallwork and Danforth Weems} } @article {51876, title = {Relationship of rumen fluid diluation rate to rumen fermentation and dietary characteristics of beef steers1,2}, journal = {Journal of Animal Science}, volume = {60}, number = {4}, year = {1985}, month = {1985}, pages = {1061-1071}, keywords = {beef, rumen, steers}, url = {/files/bibliography/85-001.pdf}, author = {Richard E. Estell and Galyean, M.L.} } @inbook {51881, title = {Ranges and pastures of the southern Great Plains and the Southwest}, booktitle = {Forages}, year = {1985}, month = {1985}, pages = {380-388}, publisher = {Iowa State University Press}, organization = {Iowa State University Press}, address = {Ames, IA}, abstract = {

The southern Great Plains and the Southwest often are called "Big Country." (See Fig. 11.1.) This not only refers to the size of individual holdings but to the sparseness of urban centers. Annual precipitation averages less than 250 mm in the lower elevations of Arizona, New Mexico, and western Texas. It ranges up to 750 mm in the eastern portions of the southern Great Plains. Precipitation not only varies greatly within and among seasons and years but also among locations separated by only a few kilometers. (See Fig. 41.2.) About 70\% of the average annual precipitation occurs during the spring-summer period in the Great Plains. In western New Mexico and southern Arizona the growing season precipitation occurs during summer, and spring normally is very dry. The entire region frequently is plagued by drought. During a prolonged drought, the Great Plains may take on a desertlike appearance.

}, url = {/files/bibliography/279.pdf}, author = {C.H. Herbel and Baltensperger, A.A.}, editor = {Heath, M.E. and Barnes, R.F. and Metcalfe, D.S.} } @article {51895, title = {The relative contributions of termites and microarthropods to fluff grass litter disappearance in the Chihuahuan Desert}, journal = {Oecologia}, volume = {67}, year = {1985}, note = {//NMSU//LTER I//}, month = {1985}, pages = {31-34}, abstract = {

We tested the hypotheses that both subterranean termites and soil microarthropods are important in the disappearance of fluff grass (Erioneuron pulchellum) litter on the soil surface by an experiment designed to separate termite and microarthropod effects. Subterranean termites (Gnathamitermes tubiformans) removed more than 50\% of the fluff grass litter in one year. Since there was no difference in mass loss of fluff grass with microarthropods present or excluded, they had no effect on decomposition of fluff grass litter. Microarthropod densities increased during the first 3 months then slowly decreased. The densities of microarthropods in fluff grass litter were too low to have a measurable effect of decomposition even if we assumed that the microarthropods consumed litter equivalent to their body weight each day.

}, keywords = {article, articles, decomposition,microarthropods, decomposition,termites, Erioneuron,decomposition, journal, journals, litter,Erioneuron decomposition, microarthropod,decomposition, pesticide, Chlordane, termite,decomposition}, doi = {10.1007/BF00378447}, url = {files/bibliography/JRN00027.pdf}, author = {Solange Silva and William P. MacKay and Walter G. Whitford} } @mastersthesis {51905, title = {Relationships between heifer traits and subsequent cow productivity measures in Hereford, Brangus and reciprocal crossbred cows}, year = {1984}, note = {//??//NONE//}, month = {1984}, pages = {57}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {cattle,breeding, cattle,productivity, dissertation, dissertations, theses, thesis}, author = {Gallagher, George R.} } @mastersthesis {51912, title = {Response of creosotebush and mesquite communities after applying hexazinone}, year = {1984}, note = {//??//NONE//}, month = {1984}, pages = {109}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, herbicide,hexazinone, Larrea community,response to herbicide, Prosopis community,response to herbicide, theses, thesis}, author = {Hoefler, William C. , Jr.} } @mastersthesis {51924, title = {The relative contributions of termites and microarthropods to fluff grass litter disappearance in the Chihuahuan Desert}, year = {1984}, note = {//NMSU//NONE, LTER//}, month = {1984}, pages = {38}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {

I tested the hypothesis that subterranean termites and soil microarthropods are important in the disappearance of fluff grass litter in the soil surface by an experiment designed to separate termite and microarthropod effects.... I found that the densities of microarthropods in fluff grass litter were too low to have a measurable effect on decomposition even if I assumed that the microarthropods consumed litter equivalent to their body weight each day. The sequence of microarthropod colonization differed from that reported for decomposition of buried litter and roots. I conclude that subterranean termites are the most important facto affecting fluff grass litter breakdown in the Chihuahuan Desert

}, keywords = {decomposition,microarthropods, decomposition,termites, dissertation, dissertations, Erioneuron,decomposition, litter,Erioneuron decomposition, microarthropod,decomposition, pesticide, Chlordane, termite,decomposition, theses, thesis}, author = {Solange Silva} } @mastersthesis {51936, title = {Relationship between termites, straw amendment and the growth of Erioneuron pulchellum in a Chihuahuan Desert ecosystem}, year = {1983}, note = {//NMSU//NONE, LTER//}, month = {1983}, pages = {109}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {The aim of this study was to examine the effect of termite removal, straw amendment, and supplemental watering on the growth of a perennial grass, Erioneuron pulchellum, in relation to total soil nitrogen levels in a Chihuahuan desert, New Mexico. Four blocks consisting of four 30 x 40 M plots were used in a randomized block design. In 1977, 10 kg ha-1 of chlordane was applied to two of the plots followed by 1800-2000 kg ha-1 of straw added in 1981. Treatments consisted of strw with termites, straw without termites, termites alone and no termites. Soil samples were taken an four dates from 06/81 to 09/82, at half and twice canopy radii of creosotebushes and at 0-5 and 5-10 cms depth at each location. Samples were analyzed for soil organic matter and for total soil nitrogen by microkjeldahl digestion. Results showed that organic matter and total nitrogen was highest under creosotebush conopies and at 0-5 cm depths. Plots with termites had lower soil nitrogen than those without and plots with straw had higher soil nitrogen when termites were present. E. pulchellum grew better on plots with termites and plots with straw than with both termites and straw and no termites and no straw. Total soil nitrogen was not implicated as contributing to these differences. The long-term effects of termite removal which contribute to reduced soil stability and water holding capacity resulted in reduced biomass production of E. pulchellum. It is suggested that termites contribute to the overall growth and survival of E. pulchellum by supplying nitrogen through recycling of above ground dead material and via carton dissolution. Carton construction is suggested to provide structural stability to the grass tussock. Supplemental watering of E. pulchellum indicated that water acted independently of the treatments although it did result in increased root nitrogen and above ground biomass of E. pulchellum, indicating a possible short-circuiting of the nitrogen available in the soil.}, keywords = {dissertation, dissertations, Erioneuron,growth, grass, Erioneuron, nutrient ammendment, straw, nutrient, nitrogen, soil nitrogen, termite, termite,soil nitrogen, termite,straw, theses, thesis}, author = {Michael F. Brown} } @mastersthesis {51969, title = {Response of three species of globemallow to germination treatments}, year = {1983}, note = {//NMSU//NONE//}, month = {1983}, pages = {55}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {A greenhouse and field study were conducted to test the effects of chemical and mechanical scarification treatments on the germination of three species of globemallow. Of the three species tested, both scarlet and orange globemallow possessed carpels surrounding the seed. A separate experiment was conducted to determine any effect the carpel might have on germination. The organic solvent dioxane proved to be the best treatments to stimulate germination. Mechanical scarification proved to be very detrimental to the germination of these species of globemallow. Compared to the dioxane treatment, removing the carpel increased the germination of scarlet globemallow but decreased the germination of orange globemallow. Due to extreme fluctuation in precipitation, the field study was a failure. It is concluded that if the inhibitory properties of the seed coat are altered, germination of globemallow can be enhanced.}, keywords = {dissertation, dissertations, germination, Sphaeralcea, plant, globemallow, plant, Sphaeralcea, Sphaeralcea, germination, theses, thesis}, author = {Roth, Timothy E.} } @article {51977, title = {Rangeland ponding dikes: Design criteria}, journal = {Journal of Range Management}, volume = {36}, number = {1}, year = {1983}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {January 1, 1983}, pages = {128-130}, abstract = {

Water ponding is used for controlling onsite and runon water while increasing infiltration and soil water storage. The dikes are constructed in a crescent or horseshoe shape, with the first dike constructed at the highest elevation on the site and additional dikes at progressively lower elevations. Some factors affecting dike construction, layout and spacing are water ponding depth, percent slope, soil type, and site topography. Such dikes have improved soil water regime on arid rangelands by increasing the infiltration opportunity and have decreased the soil erosion potential by controlling overland flow.

}, url = {/files/bibliography/252.pdf}, author = {J.M. Tromble} } @proceedings {51979, title = {Relationship of infiltration with distance to a permanent water source}, year = {1983}, month = {1983}, pages = {384}, address = {Chicago, IL}, keywords = {distance, infiltration, permanent water source}, author = {J.M. Tromble and Wood, M. K.} } @conference {51985, title = {Range management practices for reducing sediment losses from selected sites in New Mexico}, booktitle = {36th Annual Meeting, Society for Range Management}, year = {1983}, month = {1983}, pages = {No. 220}, keywords = {New Mexico, range management, sediment loss}, author = {J. C. Wood and Wood, M. K. and J.M. Tromble and Fowler, J.M.} } @article {51999, title = {The role of microarthropods and nematodes in decomposition in a semi-arid ecosystem}, journal = {Oecologia}, volume = {55}, year = {1982}, note = {//OTHER//NONE//}, month = {1982}, pages = {303-310}, abstract = {

We sampled the soil microarthropod community monthly in the oak-mesquite sand hill ecosystem. Small fungiphagous prostigmated mites (pyemotids, lordalychids and tarsonemids) that dominated the soil fauna in winter were replaced by large predaceous mites (rhodacarids and laelapids) in summer and autumn. We compared organic matter loss and microarthropod and nematode populaiton in shinnery oak (Quercus harvardii) using insecticide and untreated litter in fiberglass litterbags. Microarthropods extracted form litterbags showed a seasonal pattern similar to the soil cores except that collembolans and psocopterans were abundant in the litter and not in the soil cores. Numbers of free living nematodes were consistently greater than from untreated litter. The ratio of non-stylet bearing nematodes extracted from the litter decreased from 4:1 in one month bags to 0.8:1.0 in the one year bags. Laboratory experiments showed that rhodacarid mites fed voraciously on nematodes. Untreated litter ixhibited higher rates of organic matter loss than the insecticide treated litter; 20\% and 35\% respectively. We suggest that the abundant mesostigmatid mites prey on free living nematodes and that eliminating the predators allows the nematodes to overgraze the fungi and bacteria. The soil modifies the microclimate in buried litter allowing for higher biological activity, hence higher rates of decomposition.

}, keywords = {article, articles, decomposition,microarthropod, decomposition,nematode, journal, journals, microarthropod,decomposition, nematode,decomposition, plant,Quercus, Quercus community,decomposition, Quercus,microarthropods, Quercus,nematodes}, url = {files/bibliography/82-Oecologia-Elkins.pdf}, author = {Ned Z. Elkins and Walter G. Whitford} } @book {52022, title = {The role of nematodes in decomposition in desert ecosystems}, series = {Nematodes in Ecosystems}, year = {1982}, note = {//NMSU//NONE, LTER//ProCite field[6]: In}, month = {1982}, pages = {98-117}, publisher = {University of Texas Press}, organization = {University of Texas Press}, address = {Austin}, abstract = {Although nematodes are numerous in the soils of most ecosystems, their contribution to soil respiration is relatively small (Sohlenius 1980). Thus, judged on the basis of energy flow through an ecosystem, nematodes would have to be considered a minor component of such systems. However, the contribution of a groups of organisms to the functioning of a system cannot be judged solely on the basis of the quantity of energy processed by that group. Chew (1974) suggested that while consumers may be relatively unimportant in energy flow, they may play important roles as rate regulators. In this paper we review our findings to date on the role of nematodes in desert soil ecosystems and show how various guilds of free-living nematodes apparently regulate rates of decomposition, thus eventually affecting nutrient cycling processes.}, keywords = {book, books, chapter, chapters, decomposition,nematodes, nematode,decomposition, pesticide,nematode, report, reports}, author = {Walter G. Whitford and D. W. Freckman and Perseu F. Santos and Ned Z. Elkins and L. W. Parker}, editor = {D. W. Freckman} } @proceedings {52035, title = {Rangeland conservation needs, technology, and policy alternatives}, year = {1981}, month = {1981}, pages = {127-140}, address = {Madison, WI}, abstract = {

Range-or more appropriately rangeland-is a kind of land and not a use of land.Rangeland provides or is capable of providing forage for grazing or browsing animals. Range includes grasslands \ and \ shrublands and those forest lands that continually or periodically, naturally or through management, support an understory of herbaceous or shrubby vegetation that provides forage. Also included are those lands that have been seeded to non-native plants but are managed like lands that support native vegetation. Lands designated as improved pastures, cropland pasture, and grazed croplands are not classified as rangeland because they are routinely cultivated, seeded, fertilized, and/or irrigated.

Rangeland management is limited by environmental and economic factors. Many rangelands are dry or precipitation is so erratic that arid land management practices must be followed. However, riparian zones that occur as part of the rangeland \ ecosystem must be managed according to their particular characteristics. Other environmental characteristic that dictate range management options are steep slopes, short \ growing seasons, and \ unfavorable soil conditions. All of these environmental factors \ lower the productive capacity of the land and limit the amount and regularity of economic input into management. Cultural improvement practices, such as brush management and seeding, are most useful in attempting to improve deteriorated conditions or in meeting special management objectives. Economically inexpensive and \ energy efficient range \ management practices, such \ as controlled grazing and prescribed burning, can then be used to maintain desired \ ecological conditions.

}, url = {/files/bibliography/196.pdf}, author = {Hedrick, W.W. and Schuster, J.L. and F. Busby and C.H. Herbel and Kearl, G. and Mayland, H.F. and Renard, K.G. and Shiflet, T.N. and Teer, J.G. and Whetsell, D.} } @proceedings {52040, title = {Range research in New Mexico by ARS}, year = {1981}, month = {1981}, pages = {52-56}, address = {Las Cruces, NM}, abstract = {

Southwest depends on proper management of the forage resource. In this region, periods of low precipitation are frequent and fluctuations in seasonal and annual amounts are extreme. Substantial vegetation changes have occurred since 1900 because of past grazing abuses, severe droughts, and a rapid increase of unwanted shrubs.

The Jornada Experimental Range was established in 1912 as a 78,200ha tract 37km northeast of Las Cruces to study range management practices and the effects of weather on semidesert rangelands. Results are directly applicable to other semidesert ranges in Arizona, New Mexico, Texas, and Northern Mexico. The experimental work on the Jornada has been a combination of empirical studies on large range pastures and detailed studies of the relations among climate, soils, plants, and animals. Some of the contributions toward better management of arid rangelands are: 1) developing better utilization standards and principles of use for black grama (Bouteloua eriopoda) and tobosa (Hilaria mutica) ranges; 2) obtaining better livestock distribution by water development and salting away from water; 3) improving range livestock; 4) establishing the principles of flexible herd management to cope with a fluctuating forage crop; 5) studying the ecology of arid rangelands; 6) improving the control of mesquite (Prosopis glandulosa), creosotebush (Larrea tridentata), and tarbush (Flourensia cernua); 7) developing methods for revegetation of depleted rangelands; and 8) determining effective grazing management for sustained yielu and protection of the range resource. Continuous records of vegetation, weather, and stocking, are available for more than 65 years and assist in interpreting present studies. Additional studies, conducted prior to 1973, are summarized in bulletins prepared by Paulsen and Ares (1962): Ares (1974), and Herbel and Gould (1980).

}, url = {/files/bibliography/202.pdf}, author = {C.H. Herbel and Gibbens, Robert P.} } @article {52037, title = {Range research in the Soviet Union}, journal = {Rangelands}, volume = {3}, year = {1981}, month = {1981}, pages = {61-63}, abstract = {

In May \ and\  June \ 1979, we visited several locations in the Soviet \ Union where \ range \ research was being conducted. We were \ members of \ the \ "Arid Pastures\  \ and \ Rangelands Team" \ formed in conjunction with the US-USSR \ Agreement on\  Agriculture and \ Technology. The \ purpose of this exchange of rangelands teams was to increase cooperation in agricultural research and \ technological development tt1rough:\  \ (1) \ visiting \ selected \ USSR \ locations to \ review research on breeding, production, and \ utilization of forage produced from \ arid \ pastures \ and rangelands, and to exam- me the processes that tend to increase or decrease grazing land productivity: (2) discussing problems of mutual interest witl1 scientists and \ practitioners within the \ USSR; \ and \ (3) developing specific cooperation exchanges and research activities for the mutual benefit of both countries. We visited locations \ in\  \ Moscow, \ Leningrad, \ and\  \ Stavropol \ in \ the Republic of Russia; \ Tselinograd, Alma-Ata, and Chimkent in the Republic of Kazakhstan; Samarkand in the Republic of Uzbekistan; and \ Ashkhabad in the Republic of Turkmenia.

}, url = {/files/bibliography/200.pdf}, author = {C.H. Herbel and Barnes, R.F. and Heady, H.F. and Purdy, L.N.} } @article {52045, title = {Rangeland Improvements for New Mexico, 1976 to 1981}, year = {1981}, note = {//NMSU, USDA//NONE//}, month = {1981}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, abstract = {The primary means of insuring a viable future for our rangelands is through wise use. To this end, New Mexico State University is dedicated to the study and understanding of rangeland management. Research and Extension efforts are underway in many areas across campus and are interdisciplinary in nature. Highlights of research efforts from recent years are presented in this publication by major areas of emphasis. Results given are not in final form and if more detailed information is desired, the author should be contacted directly.}, keywords = {book, books, brush control, cattle grazing, management, cattle grazing, nutrition, chapter, chapters, herbicide, rangeland, animal damage and control, rangeland, ecology, rangeland, economics, rangeland, insect, rangeland, plant morphology, rangeland, plant physiology, rangeland, resource monitoring, rangeland, revegetation, rangeland, watershed management, rangeland, wildlife, report, reports, review,rangeland improvements}, isbn = {Special Report 41}, author = {K. C. McDaniel and E.W. Huddleston} } @article {52046, title = {Response of Muhlenbergia porteri Scribn. to season of defoliation}, journal = {Journal of Range Management}, volume = {34}, number = {2}, year = {1981}, note = {//NMSU//NONE//}, month = {1981}, pages = {91-94}, abstract = {Removing 65\% of the leaf area of bush muhly in three consecutive years during the growing season reduced plant vigor regardless of season of clipping. Late or continuous season defoliation had the greatest impact on food reserves, production, crown diameter and number of stem internodes. Defoliation during the vegetative stage had the least effect of the clipping treatments.}, keywords = {article, articles, defoliation, grasses, defoliation, Muhlenbergia, journal, journals, Muhlenbergia,defoliation, Muhlenbergia,productivity, plant productivity, plant, Muhlenbergia}, author = {Richard F. Miller and G.B. Donart} } @article {52052, title = {The role of mites and nematodes in early stages of buried litter decomposition in a desert}, journal = {Ecology}, volume = {62}, year = {1981}, note = {//NMSU//NONE//}, month = {1981}, pages = {664-669}, abstract = {

We studied changes in populations of mites, nematodes, bacteria, and fungi in buried creosote bush litter treated with selected inhibitors. Elimination of microarthropods (primarily tydeid mites) resulted in increased numbers of bacteriophagic nematodes and reduction in numbers of bacteria; elimination of both nematodes and microarthropods resulted in increased numbers of bacteria compared to untreated controls. Fungal grazing mites, Pyemotidae, and funivourous nematodes, Aphelenchus sp., increased in numbers between days 25 and 30, reducing the fungi on untreated leaves but not on stems and petioles, while mean length of fungal hyphae increased in insecticide-treated leaves. Elimination of mites resulted in a 40\% reduction in decomposition suggesting that in a desert, tydeid mites affect decomposition of buried litter by regulating the population size of the bacterial grazers, cephalobid nematodes.

}, keywords = {article, articles, bacteria,decomposition, decomposition,also SEE , decomposition,litter, fungi,decomposition, journal, journals, litter decomposition,mites, litter decomposition,nematodes, mite,also SEE , mite,tydeid, nematode,also SEE , nematode,bacteriophagic}, url = {files/bibliography/81-Ecology280-Whitford.pdf}, author = {Perseu F. Santos and Janice Phillips and Walter G. Whitford} } @conference {52056, title = {Responses of photosynthesis and root respiration to temperature, soil moisture and defoliation}, booktitle = {New Mexico State University, Agriculture Experimental Station Special Report 41}, year = {1981}, month = {1981}, pages = {37}, abstract = {Respiration processes associated with growth and maintenance of perennial plant root systems represent a significant investment of reserve nutrients since root:shoot ratios are often reater than 1. The replenisment of these reserves for aboveground and belowground plant growth through photosynthesis is often limited in semidesert rangelands by low soil moisture, high temperatures, and defoliation of photosynthetic tissue. Although photosynthesis has been quantified for a number of forage species, there is presently no information regarding reserve substrate costs (in the form of CO2 respired) for root systems of plants in a field situation. Thus, several ongoing studies were designed to define the substrate costs involved in producing and maintaining aboveground and belowground plant components and the concommitant replenishment of these reserves through photosynthesis. The important interactions of soil and air temperature, soil moisture, and defoliation are also being studied. Photosynthesis by soap tree yucca leaves provide substrates for growth of new roots and maintenance of old roots. Initial results using soap tree yucca indicate that root respiration is linearly increased by soil temperature and a doubling of rates occurs for every 10-{\textdegree}C-increase in temperature. This type of response occurs during dark periods or when photosynthesis is suppressed by either high temperature or water stress. During periods of minimal water stress and cooler air temperatures when high rates of photosynthesis occur, a photoperiod-associated rise in root respiration beyond a simple temperature response occurs. Field studies using Kleingrass show similar types of response to temperature and soil moisture. A reduction in root respiration rates following defoliation is probably associated with root growth cessation. Future research will be designed to determine physiological tolerances of important range forage species to defoliation. The approach involves, among other physiological parameters, a quantification of reserve substrates relative to environmental variables, defoliation, regrowth, and substrate gains (photosynthesis) and losses (aboveground and belowground respiration).}, keywords = {defoliation, photosynthesis, root respiration, soil moisture, temperature}, url = {/files/bibliography/205.pdf}, author = {Sisson, W.B.} } @article {52088, title = {Range research, an assessment of current problems and a strategy for the future: A summary of range research by SEA-AR in the 17 western states}, year = {1980}, month = {1981}, pages = {S-1--S-19}, institution = {Agricultural Research, Science and Education Administration, U.S. Department of Agriculture}, abstract = {

Almost half of the earth{\textquoteright}s surface is covered by rangeland, a renewable resource, a primary source of food, fiber, and contentment--the three needs basic to human life. \ As world population continues to expand at the annual rate of about 1.7 percent, the priority for food production remains foremost closely followed by the need for proper clothing and housing for an ever growing population. With affluency comes a demand for more nutritious food, better living conditions, and enhanced improvement in esthetic and recreational opportunities. This Nation{\textquoteright}s and the world{\textquoteright} s rangelands can help provide basic needs in the form of goods, services, and values, as demanded by society.

}, url = {/files/bibliography/203.pdf}, author = {C.H. Herbel and P. L. Sims and Laycock, W.A. and R. J. Lorenz and Evans, R.A. and Renard, K.G. and Barnes, R.F. and Carlson, G.E.} } @proceedings {52109, title = {Range treatment effects on infiltration rates}, year = {1980}, month = {1980}, pages = {802-808}, address = {Boise, ID}, abstract = {

Mechanical treatments of depleted, brush-infested arid rangeland is important in a rehabilitation program. The effects of rootplowing and seeding treatments were examined using a sprinkling infiltrometer, and infiltration and runoff data were compared for creosotebush, bare soil, a 1972 rootplowed and seeded treatment, and a 1976 rootplowed and seeded treatment. There were no differences among treatments in time required for runoff to begin. The plots infested with creosotebush had the greatest infiltration and the bare soil plots had the least. Under dry antecedent soil water conditions, rangeland rootplowed and seeded in 1972 had greater infiltration than that treated in 1976.

}, url = {/files/bibliography/187.pdf}, author = {J.M. Tromble} } @article {52125, title = {Response of Bouteloua eriopoda (Torr.) Torr. and Sporobolus flexuosus (Thurb.) Rybd. to season of defoliation}, journal = {Journal of Range Management}, volume = {32}, number = {1}, year = {1979}, note = {//NMSU//NONE//}, month = {1979}, pages = {63-67}, abstract = {Production, total nonstructural carbohydrates, and crown diameters were measured to evaluate the effects of season of clipping on black grama and mesa dropseed. Vegetative reproduction was also monitored for black grama. Early defoliation of both black grama and mesa dropseed had less impact on plant vigor than continuous defoliation or defoliation during the last half of the growing season. Black grama plants clipped during or after flowering, or continuously through the growing season, produced less herbage in the following year than those plants clipped during the vegetative stage. Removal of 65\% of the current year{\textquoteright}s growth any time during the growing season significantly reduced stolon numbers on black grama. Mesa dropseed clipped during maturity, during flowering, or clipped continuously throughout the growing season was negatively affected on one or more of the plant parameters measured. Clipping during the vegetative state had little apparent effect on plant vigor.}, keywords = {article, articles, Bouteloua,defoliation, defoliation, grasses, grass, black gramma,Bouteloua, grass, mesa dropseed,Sporobolus, journal, journals, plant productivity, plant, also SEE , Sporobolus,defoliation}, author = {Richard F. Miller and G.B. Donart} } @mastersthesis {52129, title = {The role of microarthropods and nematodes in litter decomposition in a Chihuahuan desert ecosystem}, year = {1979}, note = {//NMSU//US-IBP//}, month = {1979}, pages = {82}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {Changes in the decomposer communities were monitored in early stages of decomposition of buried creosotebush litter (leaves and small stems) confined in fiberglass mesh bags. Selected inhibitors (fungicides, an insecticide and nematicide) were used to disrupt the natural equilibria of the bacteria-nematode-mite litter community in order to examine the effects of removal of parts of that community in order to examine the effects of removal of parts of that community on decomposition processes. The role of microarthropods as predators regulating decomposition has not previously been described. The probable effect of microarthropods in late stages of mixed litter decomposition is to control the microbial populations directly (by grazing on fungi and dispersing microorganisms) and indirectly (by preying on microbivorous nematodes).}, keywords = {arthropod, SEE , decomposition,microarthropods, decomposition,nematodes, dissertation, dissertations, fungicide, insect, SEE , insecticide, Chlordane, litter decomposition, microarthropod,litter decomposition, nematicide, SEE , nematode,litter decomposition, soil, microarthropods, theses, thesis}, author = {Perseu F. Santos} } @mastersthesis {52151, title = {Reproductive strategies in desert annuals: test of a fixed germination hypothesis}, year = {1978}, note = {//LOCAL//NONE//}, month = {1978}, pages = {23}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {In order to optimize reproduction in unpredictable environments, Cohen has hypothesized that desert annual plant populations maintain a constant proportion of germinating seeds. The two mechanisms by which a population might maintain this germination proportion, constant at the level of the individual, or a constant population mean, have been investigated through a series of germination tests with the annual species, Pectis angustifolia Torr. (Lemonweed). Results indicate that neither of these mechanisms function to maintain a constant germination proportion. Rather, the data suggest an alternative optimal reproductive strategy by which germination proportion increases in response to increased precipitation.}, keywords = {annual plant, germination, dissertation, dissertations, germination, annual plant, reproduction, annual plant, theses, thesis}, author = {K.E. Freas} } @unpublished {JRN54835, title = {Range ewe production under twice a year lambing. II. Lamb and wool production}, year = {1978}, abstract = {

The practice of twice a year lambing offers increased opportunities for the sheep industry to expand production. The reproductive rate of sheep is determined by prolificacy and the frequency of lambing. Several experiments to breed ewes twice yearly have been reported involving many breeds of sheep (Land and McClelland, 1971; Copenhaver and Carter, 1972; Whiteman et al., 1972; Walton and Robertson, 1974; and Speedy et al., 1976). In these studies flock numbers were small and the sheep were generally managed under farm flock conditions.

The purpose of this study was to attempt to successfully breed and lamb certain genotypes of sheep twice-a-year under modified range conditions.

}, keywords = {Lamb and wool production, lambing, Range ewe production, year}, author = {L. G. McNeal and Clarence V. Hulet and J. L. Walters and W.C. Foote} } @article {52194, title = {Rate of leaf production and senescence and effect of leaf age on net gas exchange in creosotebush}, journal = {Photosynthetica}, volume = {11}, number = {2}, year = {1977}, note = {//LOCAL//US-IBP//}, month = {1977}, pages = {161-166}, abstract = {In growth chamber grown individuals of creosotebush (Larrea tridentata DC. Cov.), the dark respiration, net photosynthesis, internal leaf resistance and stomatal and cuticular resistances to H2O and CO2 were not affected (P<0.05) by leaf age. Net photosynthesis did appear to be reduced in leaves older than 47 d, but this apparent reduction was obscured by the standardization of the photosynthetic rates of change of CO2 and stomatal and cuticular resistances to CO2. An increase in the apparent rate of leaf senescence and subsequent abscission coincide chronologically with an increase in the rate of new leaf production.}, keywords = {article, articles, carbon dioxide,Larrea, journal, journals, Larrea, leaf senescence, Larrea,CO2 gas exchange, Larrea,phenology, Larrea,photosynthesis, photosynthesis,Larrea, physiology,Larrea, productivity,Larrea}, author = {J. P. Syvertsen and Gary L. Cunningham} } @conference {52199, title = {Reclamation of a low-yielding rangeland site}, booktitle = {New Mexico Academy of Science}, volume = {17}, year = {1977}, month = {1977}, pages = {30-31, No. 28}, abstract = {Nonproductive range areas have been created where the erosive forces of water and wind have removed the surface soil, exposing a subsoil which is impermeable to water. Water ponding is being studied as a possible reclamation technique. Site characterization is being accomplished by use of soil surveys, rainfall simulator, soil temperature, and soil water profile measurements. Treatments consisted of constructing and instrumenting a series of crescent- or horseshoe-shaped dikes designed to impound water 3 and 6 inches deep; any excess water flows around either end of the dike to be caught by the next lower dike. The objective is to retain water longer on the soil surface and permit additional infiltration opportunity. Ten of these dikes were constructed on the Jornada Experimental Range in the spring of 1975. They effectively caught and held water, greatly increasing the depth of soil water and lengthening the period of soil water availability when compared to untreated areas. Grasses are being seeded to hasten the recovery process. The technique looks encouraging and research efforts are continuing.}, keywords = {dikes, Jornada Experimental Range, rangeland, reclamation, soil water availability, water ponding, water retention}, url = {/files/bibliography/165.pdf}, author = {J.M. Tromble and Gibbens, Robert P. and C.H. Herbel} } @mastersthesis {52209, title = {Response of five southwestern range plants to season of defoliation}, year = {1976}, note = {//NMSU//NONE//}, month = {1976}, pages = {104}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {The objectives of this study were to (1) measure seasonal carbohydrate levels for five species occurring on Southwestern desert rangelands, (2) determine how six different defoliation patterns affect carbohydrate reserves, production, and plant growth characteristics on these five species, and (3) correlate defoliation patterns with plant phenology to maintain healthy productive plants and attain maximum forage yields. The plant species studied were black grama (Bouteloua eriopoda (Torr.) Torr.), mesa dropseed (Sporobolus flexuosus (Thurb. Rydb.)), bush muhly (Muhlenbergia porteri Scribn.), vine mesquite (Panicum obtusum H.B.K.), and fourwing saltbush (Atriplex canescens (Pursh.) Nutt.).... A high level of variability in TAC concentrations between plants generally made levels insensitive to clipping treatments. After three years of clipping only two of the five species, mesa dropseed and bush muhly, showed a significant decline in TAC levels when clipping continuously or after flowering. Physical measurements on grasses such as yield, crown diameter, stolon numbers, and number of elongated internodes were more sensitive to treatment effect. However, in fourwing saltbush the presence of considerable heterogeneity in both morphology and TAC levels within the stand made interpretation difficult.}, keywords = {defoliation, fourwing saltbush, defoliation, grasses, dissertation, dissertations, plant productivity, plant, Atriplex, plant, Bouteloua, plant, Muhlenbergia, plant, Panicum, plant, Sporobolus, theses, thesis}, author = {Richard F. Miller} } @article {52213, title = {Reproductive and vegetative growth patterns in Yucca elata Engelm (Liliaceae)}, journal = {The Southwestern Naturalist}, volume = {21}, number = {2}, year = {1976}, note = {//NMSU//US-IBP//}, month = {1976}, pages = {177-184}, abstract = {

Biomass allocated to reproductive structures in Yucca elata was compared to net leaf growth over a three year period (1971-1973) on two sites in southern New Mexico. Reproductive effort in Y. elata is dependent on the pattern of precipitational inputs, with significant inputs in the spring and previous winter having the greatest effect. Vegetative growth is curtailed during periods of reproductive growth, probably due to the large amount of energy allocated to reproductive structures. Thus, intervening periods of good vegetative growth may be necessary before a high energy cost inflorescence stalk can be produced. Cattle were found to have a major grazing impact on inflorescence stalks of smaller plants.

}, keywords = {article, articles, journal, journals, reproduction,Yucca, Yucca,growth patterns, Yucca,reproduction}, doi = {10.2307/3669953 }, url = {/files/bibliography/312.pdf}, author = {Stanley D. Smith and J. Ludwig} } @mastersthesis {52243, title = {Reproductive effort in some Chihuahuan Desert annuals}, year = {1975}, note = {//NMSU//NONE//}, month = {1975}, pages = {30}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Theoretically, desert annuals should expend more energy in reproduction during periods of environmental stress, such as water stress. In this work, the reproductive effort, in relation to moisture, of various Chihuahuan desert annuals was studied. Comparisons of reproductive effort under amended and natural soil moisture conditions were made. Under the amended water conditions, Euphorbia micromera had a lower reproductive effort. However, Bouteloua barbata and E. aristidiodes increased reproductive effort under watered conditions. Plasticity of reproductive effort was studied by comparison of reproductive effort in closely related species over a 3-year period. Species of the genera Euphorbia, Bouteloua, and Eriogonum responded to seasons with low rainfall by generally increasing reproductive effort. These results follow the expected theory that reproductive effort is higher during periods of moisture stress. Reproductive effort of summer and winter annuals in relation to moisture was also studied. A significant regression of reproductive effort onto a precipitation ratio was found in the summer annuals, but no significant relationship was found in the winter annuals.}, keywords = {annual plant, reproduction, Bouteloua,reproduction, dissertation, dissertations, Eriogonum,reproduction, Euphorbia,reproduction, reproduction, annual plant, theses, thesis}, author = {McKinney, Helen H.} } @article {52271, title = {A review of research related to development of grazing systems on native ranges of the western United States}, volume = {U.S. Department of Agriculture, Miscellaneous Publication 1271}, year = {1974}, month = {1974}, pages = {138-149}, abstract = {Research studies on grazing systems on native range in the 17 contiguous western states are reviewed. Year-long, continuous grazing was superior to seasonal grazing on the California annual rangelands. There was only limited success with any grazing scheme other than continuous on rangelands grazed only for a part of the year (seasonal ranges). The deferred-rotation system at Sonora, Texas., resulted in sufficient range improvement to permit a 33\% increase in stocking as compared to continuous grazing. Grazing research should include studies on the entire ecosystem, not on just a few of the major species. Livestock performance per unit area may be more important in evaluating grazing studies than individual animal performance. Grazing studies should be flexible to permit consideration of fluctuation in plant attributes due to variations in weather conditions. Much additional study is needed to develop the most productive grazing scheme for each range operation.}, keywords = {government publication, grazing systems, native ranges, research review, western United States}, url = {/files/bibliography/151.pdf}, author = {C.H. Herbel} } @inbook {52307, title = {Ranges and pastures of the Southern Great Plains and the Southwest}, booktitle = {Forages, the Science of Grassland Agriculture}, year = {1973}, month = {1973}, pages = {499-509}, publisher = {The Iowa State University Press}, organization = {The Iowa State University Press}, address = {Ames, IA}, abstract = {The southern Great Plains and the Southwest often are called "Big Country." This not only refers to the size of individual holdings but the sparseness of urban centers. Annual precipitation averages less than 250 mm in the lower elevations of Arizona, New Mexico and western Texas. It ranges up to 750 mm in the eastern portions of the southern Great Plains. The precipitation not only varies greatly within and among seasons and years but also among locations separated by only a few kilometers. About 70\% of the average annual precipitation occurs during the spring-summer period in the Great Plains. In western New Mexico and southern Arizona the growing season precipitation occurs during the summer and the spring period normally is very dry. The entire region is frequently plagued by drought. During a prolonged drought, the Great Plains may take on a desertlike appearance. The region may also have high winds during some periods; coupled with a reduction in vegetation and cover due to drought, this results in considerable wind erosion. The average annual evaporation ranges from 2160 mm at Oklahoma city to 3050 mm at Yuma, AZ. The frost-free period averages about 180 days in the northeastern part of the region to 340 days in the Yuma area. Elevations in the southern Great Plains vary from 200 m in southern Texas to 1200 m in northeastern New Mexico. The parts of Arizona and New Mexico considered in this chapter are desert or desert-like basins interrupted by mountains. The entire region is dissected with rivers and their accompanying floodplains. The soils are highly variable.}, keywords = {description, Great Plains, pastures, ranges, Southwest}, url = {/files/bibliography/142.pdf}, author = {C.H. Herbel and Baltensperger, A.A.}, editor = {Heath, M.E. and Metcalfe, D.S. and Barnes, R.F.} } @article {52306, title = {Rootplowing and seeding arid rangelands in the Southwest}, journal = {Journal of Range Management}, volume = {26}, number = {3}, year = {1973}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {May 1, 1973}, pages = {193-197}, abstract = {Twenty-three seedings were made across southern New Mexico following root plowing of creosotebush or tarbush. Because of the harsh environment, equipment was used that in a single operation killed the brush, formed basin pits, planted the seed on a firm seedbed and windrowed the dead brush over the seeded area. Good to excellent stands were obtained on ten plots; four had fair stands. Many of the failures were related to highly erosive or droughty sites or to soils that form a hard surface crust. Even under droughty conditions, there generally was a good stand of the seeded species where brush cover coincided with a low place where water was concentrated. The species most easily established on the sandy to loamy sites infested with creosotebush were Lehmann and Boer lovegrass, black and sideoats grama, yellow bluestem, blue panic, and fourwing saltbush. On heavier soils, the best species were sideoats grama, yellow bluestem, and alkali street-ton. The exact seed mixture for any site depends on management objectives.}, keywords = {arid rangelands, rootplowing, seeding}, url = {/files/bibliography/141.pdf}, author = {C.H. Herbel and Abernathy, G.H. and Yarbrough, C.C. and D. K. Gardner} } @conference {52359, title = {Response of creosotebush to aerially applied herbicide treatments}, booktitle = {Weed Science Society of America Meeting}, year = {1971}, month = {1971}, pages = {No. 127}, keywords = {aerial application, creosotebush, herbicide treatment}, author = {W. L. Gould and C.H. Herbel} } @article {52362, title = {A review of research related to development of grazing systems on native ranges of the western United States}, year = {1971}, month = {November 1971}, pages = {32 }, abstract = {Research studies of grazing systems on native range in the 17 contiguous Western states are reviewed. Year-long, continuous grazing was superior to seasonal grazing on the California annual rangelands. There was only limited success with any grazing scheme other than continuous on rangelands grazed only for a part of the year (seasonal ranges). The deferred-rotation system at Sonora, Texas, resulted in sufficient range improvement to permit a 33\% increase in stocking as compared to continuous grazing. Grazing research should include studies on the entire ecosystem, not just a few of the major species. Livestock performance per unit area may be more important in evaluating grazing studies than individual animal performance. Grazing studies should be flexible to permit consideration of fluctuation in plant attributes due to variations in weather conditions. Much additional study is needed to develop the most productive grazing scheme for each range operation.}, keywords = {continuous grazing, deferred-rotation grazing, flexible herd management, government publication, grazing management, grazing systems, rest-rotation grazing}, url = {/files/bibliography/129.pdf}, author = {C.H. Herbel} } @proceedings {52367, title = {The role of invertebrates in the grassland biome}, year = {1971}, note = {//USDA//US-IBP//NMSU library QH541.5 .P7 .P74//ProCite field[6]: In}, month = {September 1, 197}, pages = {267-316}, publisher = {Colorado State University}, address = {Colorado State University, Fort Collins, Colorado}, abstract = { Intraseasonal dynamics of the density of important invertebrate taxa are discussed for areas which are grazed and ungrazed by large herbivores at five sites in the U.S. IBP Grassland Biome. Ecological characteristics of the important families are discussed in relation to the 1970 intraseasonal dynamics. Principal component analyses for density and standing crop of invertebrate families are presented. Analyses of variance of density and standing crop of invertebrate taxa and standing crops of important families and trophic levels using time-weighted means for the potential growing season are presented and discussed. From these studies 15 invertebrate taxas emerged as requiring more intensive study. These are Acarina, Araneida, Coccinellidae (Coleoptera), Scarabaeidae (Coleoptera), Tenebrionidae (Coleoptera), Entomobryidae (Collembola), Lygaeidae (Hemiptera), Miridae (Hemiptera), Tingidae (Hemiptera), Cicadellidae (Homoptera), Pseudococcidea (Homoptera), Formicidae (hymenoptera), Acrididae (Orthoptera), Gryllidae (Orthoptera), and Thysanoptera.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, grassland,invertebrate, grazing,effect on invertebrates, invertebrate,grassland, invertebrate,list, list,invertebrate, proceeding, proceedings}, author = {McDaniel, Burruss}, editor = {Norman R. French} } @mastersthesis {52376, title = {The relationship of organic carbon content to carbonate and soluble Ca and Mg content in some New Mexico soils}, year = {1971}, note = {//LOCAL//NONE//}, month = {1971}, pages = {65}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {The objective of this study was to relate the organic carbon content to CaCO3 equivalent, and soluble Ca and Mg contents of some New Mexico soils. The results of this study show a significant negative correlation between organic carbon content and CaCO3 equivalent. There is a highly significant positive correlation between organic carbon content and soluble Ca, which decreases with decreasing precipitation. They also show the positive and highly significantly correlation between organic carbon content in the A horizon and soluble Ca in the B horizon (or C for soils without B horizon). A significant negative correlation was found between organic carbon content and soluble Mg content. The climate (precipitation) was an important factor influencing the relation between organic carbon content and CaCO3 equivalent, and soluble Ca in soils. These results agree with the statement of many investigators and disagree with some investigators. However, these results would be expected to apply to calcareous soils in arid and semi-arid areas..}, keywords = {biochemistry, soil, calcium carbonate,organic carbon, dissertation, dissertations, soil biochemistry, soil, calcium carbonate, soil, ions, soil, organic carbon, theses, thesis}, author = {Siriphant, Chamlong} } @proceedings {52387, title = {Range Science Department Science Series No. 2 Supplement}, year = {1970}, note = { //OTHER//US-IBP//}, month = {1970}, publisher = {Colorado State University}, abstract = { This report includes two papers which were not available last year to be published with the 437-page volume containing other papers from the Information Synthesis Project. The paper by Thomas was presented at the fourth workshop held in Woodland Park, Colorado, and the paper by Lewis was presented at the fifth workshop at Buckhorn Mountain, Colorado. Thomas\&$\#$39; paper represents a review on amphibians and reptiles as a particular type of consumer in the grassland system. Lewis\&$\#$39; paper is an overall review and integration of the other papers on producers, and especially, it contributes special new information at that trophic level. The papers are numbered according to the page after which they fit in the overall volume.}, keywords = {abstract, abstracts, amphibian,grassland ecosystem, conference, conference proceedings, conferences, grassland ecosystem, amphibians, grassland ecosystem, primary producers, grassland ecosystem, reptiles, primary producer,grassland ecosystem, proceeding, proceedings, reptile,grassland ecosystem}, author = {Dix, Ralph L and Beidleman, Richard G. (eds.)} } @conference {52388, title = {Range and forest resources of New Mexico}, booktitle = {New Mexico State University Meeting: Environment, People, and Culture}, year = {1970}, month = {1970}, pages = {10-11}, abstract = {New Mexico is big country. Its 122,600 square miles make it the fifth largest state. It extends nearly 350 miles from north to south and slightly less from east to west. Within these boundaries lie the vast extremes of sun-scorched arid land and pine-topped mountain ranges. Climate is greatly varied. Temperatures have reached54{\textdegree}F below zero in the northern mountains and 110{\textdegree}F in the southern deserts. Precipitation is low and undependable, ranging from 8 inches annually in the southern Rio Grande Valley to 20 inches in the higher mountains. The average elevation of the state is nearly 5700 feet, ranging from the low point of 2800 feet where the Pecos River enters Texas, to 13,150 feet at the top of Wheeler Peak in Taos County. New Mexico{\textquoteright}s forest and range resources are made up of six general vegetation types: grassland, woodland, forest, semidesert brush, big sagebrush and shinnery oak. Forest Service figures indicate that 23 percent of these lands, or 18.2 million acres, are forested, with 6.3 million acres of commercial forests and 11.9 million acres classed as woodland. Only 2.6 million acres of the state{\textquoteright}s 77.7 million acres are cultivated, leaving about 95 percent of the state{\textquoteright}s area available to livestock and wildlife for grazing, excluding acreage in urban and highway development.}, keywords = {forest resources, New Mexico, range resources}, url = {/files/bibliography/122.pdf}, author = {D.D. Dwyer and C.H. Herbel and C.A. Davis} } @article {52403, title = {Responses of a population of Ambystoma tigrinum to thermal and oxygen gradients}, journal = {Herpetologica}, volume = {26}, number = {3}, year = {1970}, note = {//USDA//NONE//}, month = {1970}, pages = {372-376}, abstract = {

At water temperatures below 15 C, Ambystoma tigrinum moved in response to oxygen and thermal gradients, remaining in shallow water during the day and returning to deep water at night. Under these conditions, activity was reduced. In the absence of thermal and oxygen gradients at water temperatures below 15 C, movements were random. At water temperatures above 15 C, movement was random and activity increased. Temperature appeared to be the most important factor governing winter and spring activity and light seemed most important in governing summer activity.

}, keywords = {Ambystoma,thermoregulation, amphibian, Ambystoma, amphibian, thermoregulation, amphibian,tiger salamander,Ambystoma, article, articles, journal, journals, physiology,amphibians}, url = {files/bibliography/70-Herpetologica-Whitford.pdf}, author = {Walter G. Whitford and Massey, Marvin} } @article {52420, title = {Recovery of chromic oxide administered in paper to grazing steers}, journal = {Journal of Animal Science}, volume = {29}, year = {1969}, month = {1969}, pages = {361-364}, abstract = {Chromic oxide has been used as an external indicator to determine fecal output under a wide range of conditions with diverse results. The most common method of administering Cr23 has been as powder in gelatin capsules or mixed with the ration. One of the main problems in its use in powder form is the diurnal variation pattern of excretion (Kane, Jacobson and Moore, 1952; Linnerrud and Donker, 1961; Smith and Reid, 1955). An effort was made by Corbett, Greenhalgh and McDonald (1958) to reduce diurnal variation by using paper as a carrier for the indicator. The paper, containing 20 to 30\% chromic oxide, seemed to approximate more nearly the physical characteristics of roughage rations. Corbett et al.(1960a, b) reported reduced variation when chromic oxide was administered as a component of shredded paper. Streeter and Clanton (1964) and Nelson, Kromann and Green (1966) have also found chromic-oxide-impregnated paper to be a reliable external indicator. The purpose of this study was to determine chromic oxide recovery by steers grazing tobosa (Hilaria mutica) at two stages of maturity (immature to prebloom and dormant) when chromic oxide was administered once daily as a component of shredded paper.}, keywords = {chromic oxide, gelatin capsules, recovery, shredded paper, tobosa}, url = {/files/bibliography/117.pdf}, author = {H.E. Kiesling and H.A. Barry and Nelson, A.B. and C.H. Herbel} } @article {52430, title = {Rodent populations and their impact on desert rangelands}, year = {1969}, note = {//??//NONE//}, month = {1969}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, chapter, chapters, rangeland,rodent impact, report, reports, rodent,rangeland impact}, isbn = {Bulletin 555}, author = {J. E. Wood} } @article {JRN55153, title = {Relation of body size and surface area to gas exchange in anurans}, journal = {Physiological Zoology}, year = {1968}, month = {1968}, pages = {65-85}, abstract = {

The skin, lungs, and buccal cavity may all serve as respiratory surfaces in adult terrestrial amphibians. The relative role of these respiratory surfaces has been shown to be an im- portant consideration in the ecology, geographic distribution, and phylogenetic relationships of caudate amphibians (Whitford and Hutchison, 1963, 1965, 1966, 1967). Respiration in anurans has been reviewed by Foxon (1964). Information on the comparative importance of the various respiratory surfaces in anu- rans has been based primarily on the anatomical studies of vascularization of respiratory surfaces (Czopek, 1955a, 1955b; Czopek and Czopek, 1959; Bieniak and Watka, 1962). Physiological studies dealing with the role of these respiratory surfaces in anurans have been limited to the classical studies of Krogh (1904) and Dolk and Postma (1927) on the European frogs, Rana esculenta and R. temporaria, and the recent study of Vinegar and Hutchison (1965) on the green frog, R. clamitans.

}, keywords = {adult terrestrial amphibians, buccal cavity, caudate amphibians, ecology, Geographic distribution, lungs, phylogenetic relationships, respiratory surfaces, skin}, url = {files/bibliography/68-physzool-Whitford.pdf}, author = {Victor H. Hutchison and Walter G. Whitford and Margaret Khol} } @article {JRN54838, title = {Relationship between ovulation rate and reproductive performance in sheep}, journal = {Journal of Animal Science}, volume = {26}, year = {1967}, month = {May 1967}, pages = {563-566}, chapter = {563}, abstract = {

An index or criterion for predicting \ the \ future reproductive performance of yearling ewes could be most useful \ in \ developing a more efficient sheep industry. It has long been assumed \ that \ there \ is an \ important \ relationship \ between ovulation rate and lamb production, but the repeatability of ovulation rate within a breeding season \ and \ between breeding seasons \ is unknown.

Until recently, surgical procedures have been time-consuming and have discouraged the study of \ these relationships. \ However, use of the laparotomy cradle as developed by Lamond (1963) and use of local \ anesthesia have made practical the examination of reproductive organs in large numbers of live animals.

The objective of this study was to determine the relationship between two ovulation rates measured at a 35-day interval during the peak of the breeding season and the relationship between the mean of these ovulations and \ previous lifetime lamb production. The relationship between the number of corpora lutea (CL) at the first and second observation periods to the number of embryos resulting from matings at the second observation period was also studied.

}, keywords = {ovulation rate, reproductive performance, sheep}, url = {/files/bibliography/1912-1.pdf}, author = {Clarence V. Hulet and W.C. Foote} } @proceedings {52482, title = {Reseeding in the arid southwestern United States}, year = {1965}, month = {1965}, pages = {E-23--E-24}, keywords = {arid, reseeding, southwestern United States}, author = {C.H. Herbel} } @article {52490, title = {Response of rodent populations to controls}, journal = {Journal of Wildlife Management}, volume = {29}, number = {3}, year = {1965}, note = {//NMSU//NONE//}, month = {1965}, pages = {425-437}, abstract = {A study of the response of rodent populations to poisoning was conducted on the desert grassland range of southern New Mexico. Strychnine and 1080-treated grain was distributed on a 12-section grid, each section receiving one poison in one of six distributional patterns. The 1080 poison, scattered in a 100- X 200-foot grid, was the most economical (3.5 cents per acre), and the 1080 poison gave better controls at both the 1-month and 1-year checks. The densities of the five major species within the poison area and check areas fluctuated independently, giving a decided change in the species population from year to year. Though the species composition changed, the rodent biomass remained constant on the unpoisoned area. On the poisoned area, 2 years after the poisoning, the total rodent biomass was only slightly over one-half the biomass of the uncontrolled population.}, keywords = {article, articles, community, rodent control, journal, journals, pesticide, 1080, pesticide, strychnine, rodent control}, author = {J. E. Wood} } @mastersthesis {52507, title = {The reproductive cycle of Dipodomys ordii and Dipodomys merriami in southern New Mexico}, year = {1962}, note = {//LOCAL//NONE//}, month = {1962}, pages = {28}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Reproductive data were obtained from specimens of Dipodomys ordii and Dipodomys merriami taken in southern New Mexico form October, 1960, through September, 1961. The reproductive cycles of the males and females of both species were worked out. The males of D. ordii were found to be sexually active in all months except November and the females bred in three periods: December and January, March through May and September. The males of D. merriami were sexually active all year and the females bread from January through August.D. ordii is compared to D. merriami in terms of reproduction and the possible ecological divergence is discussed. The former breeds cyclically during the breeding season and having a larger embryo number, while the latter breeds continuously during the breeding season and having a smaller embryo number.}, keywords = {Dipodomys, reproduction, dissertation, dissertations, rodent, reproduction, Dipodomys, theses, thesis}, author = {Lane, J. D.} } @mastersthesis {52519, title = {Relationship of weight of stocker calves and winter rations to pasture gains}, year = {1959}, note = {//USDA//NONE//}, month = {1959}, pages = {36}, school = {New Mexico University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {The feed-lot records of 125 weaning heifers and the summer pasture records of 89 of those heifers as yearlings were analyzed to determine the effects of initial weight, age of dam, weaning age and amount of total digestible nutrients in the winter ration on the rate of feed-lot gain, amount of feet required, cost of additional gain, the feed cost of the winter period and the effect on gain made on pasture the following summer. Age of dam and weaning age were not significantly related to feed-lot or summer gain. The regression of average daily summer gain on average daily winter gain was -0.588 pounds per day. The cost of the additional 100 pounds gain secured from adding grain to the winter ration was about $12.00. The heifers in Lot II were still heavier at the end of the summer grazing period, however, the difference between them and Lot I was reduced 6 pounds increasing the cost of the winter gain slightly. In general the calves wintered on the lighter ration gained faster the following summer than those wintered on a more liberal ration, however in year when the calves were lighter than usual the opposite was true.}, keywords = {cattle, management, cattle, nutrition, cattle, productivity, dissertation, dissertations, theses, thesis}, author = {Cline, Russell C.} } @article {52520, title = {Response of True Prairie Vegetation on Major Flint Hills Range Sites to Grazing Treatment}, journal = {Ecological Monographs}, volume = {29}, number = {2}, year = {1959}, month = {1959}, pages = {171-186}, abstract = {

Native prairie has been the home of grazing animals for untold centuries. Prairie plants are eminently adapted to grazing, and moderate grazing use is not detrimental to their development. Climax grassland when properly grazed retains essentially its natural composition. Yet, when livestock are placed on range too early in the season, when they are left there too long, or when too many animals are confined to an area, grazing becomes so excessive that normal plant cover cannot be maintained. Numerous changes in the vegetation then occur. The rate at which these changes take place depends on the degree of abuse. They sometimes take place so gradually that deterioration may not readily be recognized until the plant cover has been greatly modified, but when prairie is grazed intensively major changes may occur within a few years.

}, keywords = {changes in vegetation, excessive grazing, monograph, prairie vegetation}, url = {/files/bibliography/081.pdf}, author = {C.H. Herbel and Kling L. Anderson} } @article {52536, title = {Range management history and philosophy}, journal = {Journal of Forestry}, volume = {49}, year = {1951}, month = {September 1951}, pages = {634-638}, abstract = {Rangeland management has come a long way from the widespread, unrestricted grazing in the clays of western settlement. Early public land policy tended to encourage such grazing: Insufficient area allowed in individual homesteads, the hope of many settlers to make a stake and return to their former homes, economic pressures, and the necessity of grazing ranges closely to discourage others from settling or remainingall played a part. Such philosophy and the failure to appreciate the damage caused by overgrazing seriously deteriorated most Western ranges and left in their wake bankruptcy, blasted hopes, deserted homes and distressed communities. Fortunately, during the 50 years in which the Society of American Foresters has been growing to its present stature, range management philosophy has evolved to where conservation is more generally emphasized. Most federal range lands have been brought under administration. Private owners now have a greater appreciation of the benefits which can accrue to them and the public generally from efficient management of their ranges. Improved practices developed by research have already brought millions of dollars in savings and increased revenue to stockmen annually. Such progress might indicate that range conservation has already attained a high degree of success. However, the condition of Western ranges was so bad 50 years ago and there was such a lack of understanding of efficient range management that major progress has been attained only within recent years. This paper reviews some of the milestones in the development of range management philosophy in its relation to land use management.}, keywords = {conservation, efficient management, history and philosophy, range management, unrestricted grazing}, url = {/files/bibliography/074.pdf}, author = {Chapline, W.R.} } @article {52538, title = {Research on the College Ranch}, year = {1951}, note = {//NMSU//NONE//}, month = {1951}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, chapter, chapters, history,research, report, reports}, isbn = {Bulletin 359}, author = {Knox, J. H. and Watkins, W. E. and Koger, M. and Valentine, K. A.} } @conference {52542, title = {Rotation grazing on the Jornada and Santa Rita ranges}, booktitle = {Journal of Range Management}, volume = {3}, year = {1950}, month = {July 1, 1950}, pages = {226}, abstract = {

On the Jornada Experimental Range more total forage is obtained by grazing tobosa range during summer and reserving black grama ranges for use during the nongrowing season. Black grama range so deferred for 20 years now supports eight times as much black grama and only 1/9 as much snakeweed as adjacent comparable range grazed year long. Forage production was also maintained at a higher level under seasonal grazing. On the more uniform range types of the Santa Rita Experimental Range, where types that are adapted to grazing in only one season are not marked, advantages of rotation grazing are not so clearly evident. However, observations and data accumulated along fence lines and in small traps that have been grazed seasonally indicate that rest from grazing is beneficial at any time and that: (a) the forage composition is improved, (b) the yield of forage is higher, (c) recuperation from drought faster and (d) green forage is available later in the fall and earlier in the spring. Quantitative measurement and economic justification of rotational vs. year-long grazing must depend on results of tests now being planned.

}, keywords = {black grama, deferred grazing, Jornada Experimental Range, rotation grazing, rotational grazing, tobosa, year-long grazing}, author = {Pearse, C.K.} } @article {52544, title = {The relation of the carotene content of range forage to the vitamin A requirement of breeding cows}, journal = {Journal of Animal Science}, volume = {9}, year = {1950}, note = {//??//NONE//(New Mexico Agr. Experiment Station Journal Article 55)//}, month = {1950}, pages = {24-29}, keywords = {article, articles, biochemistry,blood plasma, carotene,cattle, cattle,biochemistry, cattle,carotene, cattle,Vitamin A, journal, journals, Vitamin A,cattle}, author = {Watkins, W. E. and Knox, J. H.} } @article {52546, title = {Range research, the foundation for range management and improvement}, journal = {American Society of Agronomy Journal}, volume = {41}, year = {1949}, month = {1949}, pages = {72-75}, abstract = {Range conservation, management and improvement have made tremendous progress during the last 50 years. During that time they have advanced from the pioneering rule-of-thumb stage to a science based on tested knowledge. Although there are many unanswered problems and further opportunities for development, still, research has laid a secure foundation for better range forage and livestock production. The transfer of the forest reserves from the Department of Interior to the Department of Agriculture in 1905 laid the groundwork for this progress. Previously, Mr. Gifford Pinchot, Mr. A. F. Potter and Dr. Frederick V. Coville made a survey of the public lands and recommended their control and regulation. It was natural, therefore, for these three to team up in developing a sounder basis of grazing for the national forests, as they came to be called upon transfer of authority. Pinchot was Chief of the Forest Service. He brought Potter in to head up grazing administration. And Dr. Coville was chief of the Division of Botany in the Bureau of Plant Industry. Between the three of them they planned for range studies which would facilitate efficient grazing administration on the national forests.}, keywords = {range improvement, range managment, range research}, url = {/files/bibliography/071.pdf}, author = {Chapline, W.R.} } @article {52551, title = {The repeatablility of the yearly production of range cows}, journal = {Journal of Animal Science}, volume = {6}, year = {1947}, note = {//??//NONE//(New Mexico Agr. Exp. Station Journal Article 41)//}, month = {1947}, pages = {461-466}, keywords = {article, articles, cattle, productivity, journal, journals}, author = {Koger, M. and Knox, J. H.} } @article {52564, title = {Record of alligator juniper (Juniperus pachyphloea Torr.) on the Jornada Experimental Range, New Mexico}, journal = {The American Midland Naturalist}, volume = {32}, year = {1944}, month = {1944}, pages = {518}, abstract = {

The record of the flora of the Jornada Experimental Range in south central New Mexico does not include the Alligator juniper (f. pachuphloea Torr.). (See Little and Campbell, 1943, Amer. Midland Natur., vol. 30., no. 3, p. 656.) Visits just south of the area on Black Mountain at the southern end of the San Andres Range and to Rhodes Pass, approximately 40 miles to the north, in the northern part of the San Andres Mountains have shown the tree to be a common dominant at suitable locations at approximately 6500 feet elevation. As it was expected that the tree might be found between these two areas on the Jornada Experimental Range, careful note was taken on field trips. In November 1943, a single tree was found in Ash Canyon; since then two more trees have been located, one in St. Nicholas Canyon and one near Goldenburg Springs, all on the Jornada Range. A specimen is now in the field herbarium at the headquarters area of the Jornada. Doubtless, further search will reveal more specimens of this species scattered among the more common one-seeded junipers (J. monosperma) and pinyon pines (P. edulis), the only other members of the Pinaceae on the area.

}, keywords = {alligator juniper, Jornada Experimental Range, specimens}, url = {/files/bibliography/068.pdf}, author = {A.F. Halloran and F.N. Ares} } @article {52565, title = {Range cattle management on the Jornada Range}, journal = {American Cattle Producer}, volume = {24}, number = {12}, year = {1943}, month = {May 1943}, pages = {7-10}, abstract = {

With a great demand beef at good prices, such as prevails today, there is apt to be less and less attention given to the various management aspects of operating cattle outfits. Yet, as every seasoned cattleman knows, it is just as important and perhaps even more so to keep a line on range management costs and income during good times as during lean years. During good years, there is a greater chance of management factors getting out of balance, which may lead to later difficulties. Then too, no one knows when or how quickly the fat years will turn to lean. This is particularly so in the Southwest where cattle ranching is influenced by many factors, some of which, particularly drought, are beyond control of the operator. In this region, good range management practices have a direct bearing on costs and returns which in the end tell whether or not a stockman stays in business.

}, keywords = {cattle management, range management}, url = {/files/bibliography/059.pdf}, author = {F.N. Ares and Valentine, K. A.} } @article {52573, title = {Reseeding practices for New Mexico ranges}, year = {1942}, note = {//??//NONE//}, month = {1942}, institution = {New Mexico Agricultural Experiment Station}, keywords = {book, books, chapter, chapters, report, reports, seeding}, isbn = {Bulletin 291}, author = {Bridges, J. O.} } @article {52576, title = {Range management}, journal = {Western Livestock Journal}, volume = {19}, year = {1941}, month = {1941}, pages = {55}, keywords = {management, range, range management}, author = {F.N. Ares} } @article {52578, title = {Reseeding trials on arid rangeland}, year = {1941}, note = {//??//NONE//}, month = {1941}, institution = {New Mexico Agricultural Experiment Station}, keywords = {book, books, chapter, chapters, rangeland,seeding, report, reports, seeding}, isbn = {Bulletin 278}, author = {Bridges, J. O.} } @article {52581, title = {Range management research methods in the western United States}, journal = {Herbage Reviews}, volume = {8}, year = {1940}, month = {1940}, pages = {121-138}, abstract = {The great rangeland in the western half of the United States covers a territory approximately 1,000 miles wide and 1,200 miles long within which some 728 million acres of mountains, foothills, plains, and semidesert are grazed at various seasons of the year by millions of cattle, horses, sheep, and goats, as well as big game and other wild animals. The range research problem is to determine how the continued productivity and use of this vast native forage resource can be maintained at the highest level in harmony with economic livestock production and the conservation of other resources on the range, such as timber and water for irrigation, and with the feed production of the associated lands in cultivation. This means working out the proper utilization and management of the rather sparse vegetation growing under usually low rainfall and easily damaged by too heavy grazing, especially during recurrent severe drought periods.}, keywords = {conservation of resources, economic livestock production, productivity, range management}, url = {/files/bibliography/053.pdf}, author = {R.S. Campbell} } @article {52582, title = {Revegetating semidesert range lands in the Southwest}, year = {1940}, month = {May 1940}, pages = {22 }, publisher = {U.S. Government Printing Office}, abstract = {In Arizona, New Mexico, and southwestern Texas are several million acres of deteriorated semidesert range that are in need of revegetation. Parts of this area may be revegetated naturally through better range management practices alone, such as conservative grazing and deferred-rotation grazing. Other lands, deteriorated to various degrees and requiring various methods of restoration, require artificial reseeding and planting. It is the purpose of this pamphlet to outline the best methods developed to date for artificially revegetating such ranges but without any implication that artificial revegetation is to beconsidered a substitute for good range management. These methods are presented as aids in starting or hastening natural recovery processes on relatively small areas requiring special attention.}, keywords = {conservative grazing, deferred-rotation grazing, deterioration, government publication, range management, revegetation}, url = {/files/bibliography/054.pdf}, author = {Cassady, J.T. and Glendening, G.E.} } @article {52584, title = {Range forage utilization}, journal = {The Hereford Journal}, volume = {29}, number = {23}, year = {1939}, month = {April 1, 1939}, pages = {39, 46}, abstract = {The degree of utilization of forage on Southwestern ranges is one of the most important factors in range management and livestock production and, as such, warrants considerable study and experimentation. In fact, the importance of utilization studies can hardly be overemphasized since not only the restoration of our depleted ranges but also the maintenance of all our valuable grazing lands depends directly on fixing certain standards of utilization which, if adhered to, will insure against that close, destructive grazing of perennial forage plants which so impairs and weakens their vitality that a high mortality is usually sustained during the frequent drought year.}, keywords = {livestock production, range management, utilization of forage}, url = {/files/bibliography/046.pdf}, author = {F.N. Ares} } @article {52591, title = {Range research contributes to progress in range management}, journal = {Cattleman}, volume = {25}, number = {11}, year = {1939}, note = {//??//NONE//}, month = {1939}, pages = {65, 67-69}, keywords = {article, articles, journal, journals, range management}, author = {Upson, A. and McGinnies, W. G.} } @article {52629, title = {"Red Beds" and associated formations in New Mexico}, year = {1928}, note = {//??//NONE//}, month = {1928}, pages = {183-197, 324, 326, 339}, institution = {U.S. Geological Survey}, keywords = {book, books, chapter, chapters, geomorphology, report, reports}, isbn = {Bulletin 794}, author = {Darton, N. H.} } @article {52636, title = {Range and cattle management during drought}, year = {1922}, month = {May 15, 1922}, pages = {84 }, institution = {Government Printing Office}, abstract = {

In the past, cattle production on Southwestern ranges has been a business with \"ups and downs,\" with prosperity or adversity governed by climatic conditions, which brought seasons of plenty in range forage and stock water followed by seasons of restricted forage growth and scarcity of water. Soon after the cattle business became established on the open public range of the Southwest, the herds were built up during a period of good years until the developed ranges were stocked fully or beyond the number they could carry even in good years. Then, at intervals, came dry periods, series of dry years with much less forage produced than was required by the stock on the range and with heavy losses from starvation. During the early days, before all the ranges had been opened up, there was opportunity to develop new range during such emergencies and, thus, to relieve the situation to some extent. Such possibilities diminished more and more, however, as practically all the range came into use. During the drought that ended in 1910, there was little opportunity of this nature and practically none in the drought of 1916 to 1918. The setback to the livestock industry, caused by the combination of unfavorable climatic conditions and unwise range practice, comes about mainly through heavy losses of stock, low calf crop, interference with improvement of breeding herds, retarded growth of young stock and range deterioration. During the last drought (1916 to 1918), according to estimates based on the best data obtainable, losses were at an average rate of 20 per cent annually for the three-year period and reached as high as 35 per cent in 1918, the worst year of the drought. Individual losses were as high as 50 per cent. The large reduction in calf crop is probably next in importance to losses. Natural increase is the main source of income, and if greatly reduced at a time when expenses are high, the result is serious. The calf crop for some of the ranges affected by the last drought was estimated at 35 per cent in 1917, 25 per cent in 1918 and 35 per cent in 1919, the three years most influenced by the drought. These figures are probably not far from representing the true situation. Drought also has been a prime factor in retarding improvement in the grade of stock. Heavy losses and forced sales might wipe out years of effort in building up the herd or reduce the numbers to an extent that culling and selection necessary to maintain quality would not be consistent with the importance of increasing the herd to take advantage of good years; or, the set-back might be such that it left the stockman financially unable to purchase the right kind of bulls.

}, keywords = {cattle management, drought, government publication, range management}, url = {/files/bibliography/008.pdf}, author = {Jardine, J. T. and Forsling, C.L.} } @article {JRN54199, title = {Range Cow Maintenance on Yucca and Sotol}, volume = {114}, year = {1918}, publisher = {New Mexico College of Agriculture and Mechanic Arts}, abstract = {

Owing to the overstocking of the ranges and the not infrequent drouths of the Southwest, stockmen in this region have for years been seeking some native plants, inured ot the climate not ordinarily considered a stock food that would help out these conditions.\  The experiments in this direction have already shown the value of some varieties of the cactus for this prupose.\  The investigations of the Station, conductied by Professor R.F. Hare\  a number of years ago, both at this institution and at San Antonio, Texas, in co-operation with the United States Department of Agriculture, showed the composition, digestibility and food value of the cactus, and developed new methods of handling and feeding it.\  The results of this investigation are published in Bulletin No. 60. "Prickly Pear and Other Cacti as Food for stock," by D. Griffiths and R.F. Hare.

}, keywords = {cactus, sotol, Turney, Yucca}, url = {/files/bibliography/1918-1.pdf}, author = {Foster, Luther and Humble, Cleveland W.} } @article {52651, title = {The range problem in New Mexico}, year = {1908}, month = {April 1908}, pages = {46 }, address = {Las Cruces}, abstract = {

The conservation of our natural resources and their proper use constitute the fundamental problem which underlies almost every other problem of our national life. Unless we maintain an adequate material basis for our civilization, we cannot maintain the institutions in which we take so great and so just a pride; and, to waste and destroy our natural resources means to undermine this material basis. (Roosevelt)

}, keywords = {conservation, government publication, natural resources, range problem}, url = {files/bibliography/001-1.pdf}, author = {Wooton, E.O.} } @book {52655, title = {Report on a route from Fort Smith to Santa Fe}, series = {31st Congress of the United States}, volume = {Sen. Ex. Doc. 64}, year = {1850}, note = {//NMSU, USDA//NONE//}, month = {1850}, pages = {197-198}, keywords = {book, books, chapter, chapters, history, report, reports}, author = {Marcy, R. B.} }