@conference {JRN55355, title = {Testing of a LoRa-WAN digital ranching system on desert rangelands: Some practical experiences}, booktitle = {2021 NMSU ACES BEEF, DAIRY AND LIVESTOCK UPDATE Presented by NMSU Cooperative Extension Service}, year = {2022}, month = {1/25/2022}, abstract = {Precision livestock farming (PLF) is an emerging agricultural strategy that incorporates sensors and data analytics to inform management decisions (Neethirajan, 2017; Tedeschi et al., 2021). Though common in household and more intensive livestock and crop production systems, Internet of Things (IoT) tools are in earliest stages of development for extensive beef and sheep production systems on arid rangeland primarily due to limited infrastructure and lack of Wi-Fi, cellular (e.g. 3 and 4G), or satellite network access. Yet Long Range Wide Area Networks (Lora-WAN) could offer a high efficiency and low-cost solution to this hindrance as they promise near-real time long-range coverage (e.g. > 6 mi), a strong signal, long battery life, and customizable data collection units (e.g. widgets or sensors), compared to other conventional network types (Bocquier et al., 2014). Precision livestock technologies could provide New Mexican livestock producers novel tools for realtime monitoring of animal location and activity, asset tracking, and infrastructure monitoring in the face of a dwindling workforce and harsher climate (Spiegal et al., 2020). This study aimed to test a PLF LoRa-WAN-based monitoring system across four pastures (12,000 ac) of Chihuahuan Desert rangeland. We report the installation protocol, maintenance, and practical applications associated with the system.}, keywords = {beef cattle, digital agriculture, GPS-tracking, Precision grazing, Precision livestock farming, rain gauge sensor, water level sensor}, url = {files/bibliography/21-059.pdf}, author = {Matthew M. McIntosh and Andr{\'e}s F. Cibils and S. Nyamuryekung{\textquoteright}e and Richard E. Estell and Andrew Cox and Danielle Duni and S. A. Utsumi and Qixu Gong and Tony Waterhouse and J P Holland and Huiping Cao and LE Boucheron and H. Chen and S. Spiegal} } @conference {JRN55407, title = {Training beef cattle to use virtual fence systems}, booktitle = {2nd US Precision Livestock Farming Conference May 2023}, year = {2022}, month = {08/03/2022}, abstract = {Virtual fencing (VF) is an alternative method to control livestock dispersal. This method consists of the use of animal wearable collars that employ auditory-electric pulse cues to deter animals from trespassing a virtually determined fence boundary. Despite VF suggesting promising applications for Precision Livestock Farming, there is limited information on best practices to train groups of cattle to VF configurations effectively. Eleven Brangus cows of the New Mexico State University{\textquoteright}s Chihuahuan Desert Rangeland Research Center were allocated three days to feeding areas (0.19 ha) treated with or without VF exclusions. The process was repeated for two periods (1 vs. 2), lasting six days each. The VF collars communicated real-time animal positions and activity at 15-minute and 30-minute intervals. Treatment effects of study (with vs. without VF-exclusion), period, and its interaction were analyzed via an ANOVA to compare auditory-electric pulses emitted during the deployment. The number of auditory-electric pulses per cow differed (P < 0.001) due to a study by period interaction. Exposure to VF in period 1 triggered a greater (P <0.003) frequency of auditory (3.3 vs. 0.7 {\textpm}0.3) and pulses (1.3 vs. 0.1 {\textpm}0.1) per cow than in period 2. Activation of VF reduced differently (P =0.05) the time spent on excluded areas in period 1 (7.8 vs. 1.7 {\textpm}0.4 h) and period 2 (4.8 vs. 0.0 {\textpm}0.4 h) due to treatment by period interaction. Results indicate that cows adjusted rapidly to VF configurations by minimizing the frequency of pulses and relying increasingly on auditory to alter behavior.}, keywords = {animal wearable collars, beef cattle, fence boundary, training, virtual fence systems}, author = {S. Nyamuryekung{\textquoteright}e and Andrew Cox and Perea, A. and Richard E. Estell and Andr{\'e}s F. Cibils and J P Holland and Tony Waterhouse and G. Duff and M. Funk and Skye Aney and Matthew M. McIntosh and S. Spiegal and Brandon T Bestelmeyer and S. A. Utsumi} } @article {JRN55385, title = {Toward a sustainable grassland ecosystem worldwide}, journal = {The Innovation}, volume = {3}, year = {2022}, month = {7/12/2022}, pages = {e100265}, chapter = {4}, abstract = {Globally, grasslands, covering about 40\% of the Earth{\textquoteright}s land area, are vital for supporting important ecosystem functions, services, and livelihoods of millions of humans. Currently, grassland degradation is a major threat to the maintenance of ecological services,1 food security, and sustainable development, and directly hinders the global efforts with meeting goals and targets such as the The UN Decade on Ecosystem Restoration and Sustainable Development Goals (SDGs). Remote sensing approaches have the advantages of spanning large geographical areas with multiple spatial, spectral, and temporal resolutions. In global scale, remote sensing methods used normalized difference vegetation index to determine net primary productivity (NPP), which still is the effective method to indicate grassland conditions. To master the general situation of grassland, we analyzed the global spatial-temporal variation of NPP from 2001 to 2019 at the pixel level across the globe. As presented in Figure 1A, the NPP values of global grasslands showed an obvious variation trend, which indicated a considerable distribution pattern of spatial heterogeneity. The decreasing and increasing trend in grassland NPP covered approximately 25.3\% and 74.5\% of the total grassland area, respectively. We observed the highest proportion of degradation in Australia (45.5\%). Conversely, 73.7\% of the total grassland area revealed an increasing NPP trend, especially in Canada (86.4\%). These changes are predicted to have huge effects on biodiversity and the livelihoods of approximately 1.5 billion people who rely on grassland ecosystem services and sustainability. (A) Global trends of grassland degradation and restoration. The significance of the grassland dynamics was determined by the F-test to represent the confidence level of variation. Then, the variation trend in grassland NPP was classified into the following 6 categories based on the F-test: ED (extremely significant degradation, slope < 0, p < 0.01); SD (significant degradation, slope < 0, 0.01 < p < 0.05); LD (light degradation, slope < 0, p > 0.05); LR (light restoration, slope > 0, p > 0.05); SR (significant restoration, slope > 0, 0.01 < p < 0.05); and ER (extremely significant restoration, slope > 0, p < 0.01). (B) Grassland degradation definitions and grassland sustainability assessment.Different colors represent the focus of different periods of grassland degradation definitions from biotic/abiotic indicators to ecosystem sustainability. Collaborations and mutual relationship of policymaker-performer-evaluator (e.g., government, scientist, rancher). Comprehensive assessment of grassland sustainability from indicators, functions, services, and establish links with climate, soil and grassland conditions, livestock management and trades, herder economics, and effectiveness of policy.}, keywords = {ecosystem, ecosystem restoration, globally, grassland, sustainable, sustainble development goals, vegetation}, doi = {10.1016/j.xinn.2022.100265}, url = {files/bibliography/22-014.pdf}, author = {Jian Sun and Yi Wang and Shilong Piao and Miao Liu and G. Han and Junran Li and Eryuan Liang and Tien Ming Lee and Guohua Liu and Andreas Wilkes and Shiliang Liu and Wenwu Zhao and Huakun Zhou and Mesenbet Yibeltal and Mulatu Liyew Berihun and Dawn M. Browning and Ayele Almaw Fenta and Atsushi Tsunekawa and Joel R. Brown and Walter Willms} } @article {JRN55349, title = {Towards routine mapping of crop emergence within the season using the harmonized Landsat and Sentinel-2 dataset}, journal = {Remote Sensing}, volume = {13}, year = {2021}, month = {12/14/2021}, pages = {5074}, abstract = {Crop emergence is a critical stage for crop development modeling, crop condition monitoring, and biomass accumulation estimation. Green-up dates (or the start of the season) detected from remote sensing time series are related to, but generally lag, crop emergence dates. In this paper, we refine the within-season emergence (WISE) algorithm and extend application to five Corn Belt states (Iowa, Illinois, Indiana, Minnesota, and Nebraska) using routine harmonized Landsat and Sentinel-2 (HLS) data from 2018 to 2020. Green-up dates detected from the HLS time series were assessed using field observations and near-surface measurements from PhenoCams. Statistical descriptions of green-up dates for corn and soybeans were generated and compared to county-level planting dates and district- to state-level crop emergence dates reported by the National Agricultural Statistics Service (NASS). Results show that emergence dates for corn and soybean can be reliably detected within the season using the HLS time series acquired during the early growing season. Compared to observed crop emergence dates, green-up dates from HLS using WISE were ~3 days later at the field scale (30-m). The mean absolute difference (MAD) was ~7 days and the root mean square error (RMSE) was ~9 days. At the state level, the mean differences between median HLS green-up date and median crop emergence date were within 2 days for 2018{\textendash}2020. At this scale, MAD was within 4 days, and RMSE was less than 5 days for both corn and soybeans. The R-squares were 0.73 and 0.87 for corn and soybean, respectively. The 2019 late emergence of crops in Corn Belt states (1{\textendash}4 weeks to five-year average) was captured by HLS green-up date retrievals. This study demonstrates that routine within-season mapping of crop emergence/green-up at the field scale is practicable over large regions using operational satellite data. The green-up map derived from HLS during the growing season provides valuable information on spatial and temporal variability in crop emergence that can be used for crop monitoring and refining agricultural statistics used in broad-scale modeling efforts.}, keywords = {crop growth stages; start of the season; green-up; crop progress; crop condition; land surface phenology; remote sensing phenology; time-series analysis; Landsat; Sentinel-2}, doi = {10.3390/rs13245074}, url = {files/bibliography/21-056.pdf}, author = {Feng Gao and Martha Anderson and David M. Johnson and Robert Seffrin and Brian Wardlow and Andrew Suyker and Chunyuan Diao and Dawn M. Browning} } @article {JRN55329, title = {Ten practical questions to improve data quality}, journal = {Rangelands}, year = {2021}, month = {8/24/2021}, pages = {1-12}, abstract = {On the Ground {\textbullet} High-quality rangeland data are critical to supporting adaptive management. However, concrete, cost-saving steps to ensure data quality are often poorly defined and understood. {\textbullet} Data quality is more than data management. Ensuring data quality requires 1) clear communication among team members; 2) appropriate sample design; 3) training of data collectors, data managers, and data users; 4) observer and sensor calibration; and 5) active data management. Quality assurance and quality control are ongoing processes to help rangeland managers and scientists identify, prevent, and correct errors in past, current, and future monitoring data. {\textbullet} We present 10 guiding data quality questions to help managers and scientists identify appropriate workflows to improve data quality by 1) describing the data ecosystem, 2) creating a data quality plan, 3) identifying roles and responsibilities, 4) building data collection and data management workflows, 5) training and calibrating data collectors, 6) detecting and correcting errors, and 7) describing sources of variability. {\textbullet} Iteratively improving rangeland data quality is a key part of adaptive monitoring and rangeland data collection. All members of the rangeland community are invited to participate in ensuring rangeland data quality.}, keywords = {data quality, monitoring, quality assurance, quality control}, doi = {10.1016/j.rala.2021.07.006}, url = {files/bibliography/21-039.pdf}, author = {Sarah McCord and Justin L. Welty and Jennifer Courtright and Catherine Dillon and Alex Traynor and Sarah Burnett and Ericha Courtright and G. Fults and Jason W. Karlgh and Justin Van Zee and Nicholas Webb and Craig Tweedie} } @article {JRN55171, title = {Traversing the Wasteland: A Framework for Assessing Ecological Threats to Drylands}, journal = {BioScience}, volume = {70}, year = {2020}, month = {January 2020}, pages = {35{\textendash}47}, abstract = {

Drylands cover 41\% of the Earth{\textquoteright}s terrestrial surface, play a critical role in global ecosystem function, and are home to over two billion people. Like other biomes, drylands face increasing pressure from global change, but many of these ecosystems are close to tipping points, which, if crossed, can lead to abrupt transitions and persistent degraded states. Their limited but variable precipitation, low soil fertility, and low productivity have given rise to a perception that drylands are wastelands, needing societal intervention to bring value to them. Negative perceptions of drylands synergistically combine with conflicting sociocultural values regarding what constitutes a threat to these ecosystems. In the present article, we propose a framework for assessing threats to dryland ecosystems and suggest we must also combat the negative perceptions of drylands in order to preserve the ecosystem services that they offer.

}, doi = {10.1093/biosci/biz126}, url = {files/bibliography/20-005.pdf}, author = {David L. Hoover and Brandon T Bestelmeyer and N.B. Grimm and T. Huxman and Sasha C. Reed and O. E. Sala and Timothy R Seastedt and Timothy R Seastedt and Hailey Wilmer and Scott Ferrenberg} } @conference {JRN55202, title = {Terradactyl: an example of modularity and ontologies to ensure the sustainability of open source software}, booktitle = {Society for Range Management}, year = {2020}, month = {02/2020}, address = {Denver, CO}, abstract = {Data-driven rangeland management relies on the ability to flexibly access monitoring data that is relevant to the multitude of challenges on the nation{\textquoteright}s rangelands. Terradactyl is an R package with facilitates the modular use and re-use of rangeland monitoring data. Data are first divided and organized into a tall format which allows for modular data analysis. These data can then be easily analyzed using a modular range of rangeland indicator calculation function. These functions stack together in a way that is increasingly modular. For instance, the pct_cover() function is the foundation for pct_cover_bare_soil(), pct_cover_species(), so that the same code supports functionally similar indicator calculations. This means that terradactyl can be used to support a range of management questions across many different kinds of monitoring data.}, author = {Sarah McCord and Nelson Stauffer} } @article {JRN55253, title = {Twenty-five years and a wiser science}, year = {2019}, month = {11/2019}, pages = {Page 3}, abstract = {Scientists are now better equipped than ever to help unify communities and chart solutions to changing climate, aging ranchers, globalization, new technologies, and changing values. As we work on the next 25 years, we should be prepared to learn how much we have yet to understand about Nature, one another, and ourselves.}, author = {Brandon T Bestelmeyer} } @conference {JRN54990, title = {Terradactyl: R Package for rangeland core methods data extraction and calculation}, 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 = {

Grassland, Shrubland, and Savanna Ecosystems are widely adopted by federal land management agencies, such as the Bureau of Land Management (BLM) and Natural Resources Conservation Service (NRCS), research institutions, and other land management organizations. Within the BLM and NRCS these data are stored in large databases and are generally shared with collaborators and partners via file geodatabase or text file. While a limited suite of indicator calculations is available with these raw data, custom calculations can be complicated given the differences in data structure. Here we present an R package, called terradactyl, which handles data formats from the BLM TerrAdat database, the NRCS Natural Resources Inventory, and the Database for Inventory Monitoring and Assessment. This package provides several groups of functions. The first are a set of tidying functions, which gather data from BLM and NRCS data files into a common long data format to improve calculation efficiency. The second set of functions provide a grammar of rangeland indicator descriptions within which specific classes of indicators (e.g., cover) can be flexibly calculated based on user\&$\#$39;s categorical inputs. The third set of functions provide outputs specifically formatted for the inputs into modelling applications such as AERO, RHEM, and APEX or specified data archiving formats, such as the BLM\’s Terrestrial Indicators table. This R package is used by both the BLM and the NRCS to compute calculations from core methods data and is a powerful tool for integrating core methods data from different datasets.

}, author = {Sarah McCord and Nelson Stauffer} } @conference {JRN54994, title = {Trials and tribulations of quantifying hotspots of cattle use in large desert pastures}, 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 = {

Overuse of particular locations by cattle in arid environments is associated with perennial grass loss, lateral soil redistribution, dust emissions, and suboptimal forage utilization. We sought to identify the abundance and distribution of hotspots (i.e., locations with multiple visits of long duration) for two types of cattle (Raramuri Criollo, Angus x Hereford) alternating use of a large desert pasture during four phenologically-defined seasons in 2008. We used Gridded Time-Use Maps in the Time Local Convex Hulls (T-LoCoH) package in R to quantify the distribution of both types during the four seasons. This entailed creating a map for each of 32 cows (4 collared cows x 8 trials), and then creating 8 maps {\textendash} one per trial {\textendash} illustrating, per cell, the average number of visits and average duration of those visits. Most hotspots were adjacent to watering points, and they were least abundant during the season with the greatest pasture-level forage production. These results were expected in a general sense, but there were several decision points during the analysis, and had we decided differently, different counts and locations of hotspots would have been identified. For instance, we used expert knowledge to a) select the size of the cells (150 x 150 m), b) define a {\textquotedblleft}visit{\textquotedblright} (at least one occurrence in a cell separated by at least 12 hours from the previous occurrence in that cell), and c) designate cells as hotspots (cells visited on average \> 4 times for \> 2 hours). Most analytical methods entail some decision-making, and we found T-LoCoH to be highly useful for our research questions. We seek to discuss the utility of T-LoCoH, and our choices for it, with the SRM livestock tracking community to identify whether there might be guiding principles for all when using the tool to quantify cattle use hotspots.

}, author = {S. Spiegal and Richard E. Estell and Andr{\'e}s F. Cibils and D. K. James and H. Raul Peinetti and Dawn M. Browning and Kirsten B. Romig and Amy L. Gonzalez and Andrew Lyons and Brandon T Bestelmeyer} } @conference {JRN54913, title = {A Tale of Two Thresholds: Mistakes and Serendipity in a Desert Grassland}, booktitle = {Ecosystems}, year = {2018}, month = {08/2018}, publisher = {Ecological Society of America}, organization = {Ecological Society of America}, address = {New Orleans, LA}, abstract = {

Semiarid grasslands have crossed thresholds to shrub-dominated states due to heavy grazing episodes and their after-effects. Extreme weather events and restoration actions can catalyze varying degrees of grass recovery. While we understand these thresholds in biophysical terms, we have scarcely explored their ultimate societal causes. I will reconstruct thought processes underpinning historical desertification events on the Jornada Experimental Range, including some recent first-hand experiences. I also describe how such {\textquotedblleft}mental models{\textquotedblright} underpin restoration success. Given the large management extents and heterogeneity inherent to drylands, I argue that appropriate mental models are the most important tools we have to manage thresholds.

}, author = {Brandon T Bestelmeyer} } @conference {JRN54919, title = {Toward Accessible, Discoverable, and Usable Crop Insurance Data: Multi-scale Analysis and Visualization of Cause of Loss}, booktitle = {16th Annual Climate Prediction Applications Science Workshop (CPASW)}, year = {2018}, month = {05/2018}, publisher = {16th Annual Climate Prediction Applications Science Workshop (CPASW)}, organization = {16th Annual Climate Prediction Applications Science Workshop (CPASW)}, address = {Fargo, ND}, abstract = {

The synthesis and analysis of existing {\textquoteleft}big data{\textquoteright} can increase the overall collective value and yield additional insight of such knowledge. The creation of the U.S. Department of Agriculture (USDA) Climate Hub network prioritizes this with information synthesis and tool development as tangible outputs. The Hubs{\textquoteright} mission is to develop and deliver science-based information and technologies to agricultural and natural resource managers to enable climate-informed decision-making. As part of this, Hubs work across USDA agencies to synthesize existing information to meet the needs of our ultimate stakeholders - farmers, ranchers, and land managers. The USDA Risk Management Agency (RMA) is responsible for overseeing the Federal crop insurance program and works with private insurance companies. RMA has collected annual cause of loss data since the mid-1900s with monthly data beginning in 1989. These data describe the reason for loss (e.g., drought, wind, irrigation failure), indemnity amount (i.e., total cost of loss), as well as relevant spatio-temporal information (i.e., state, county, year, month). We describe an initial retrospective analysis at multiple spatial and temporal scales over the United States. Drought and excess moisture were the top two causes of loss since 2001, and were responsible for over 70\% of nationwide climate-related crop loss payments. Regional differences in top causes of loss demonstrate the complex interactions of biophysical, climatic, socio-economic, and geo-political factors. Causes of loss over time show distinct trends as a function of major weather disasters and long-term climate events, such as drought. A web-based tool was then developed to deliver these crop insurance data to our partners and stakeholders for increased accessibility, discoverability, and usability. Ultimately, we envision the project supporting land management decisions and ecosystem resilience.

}, author = {J.T. Reyes and Andrew Eischens and Shilts, Mark and Jebediah C. Williamson and Emile H. Elias} } @proceedings {JRN54860, title = {Testing the ecological site group concept}, volume = {January 28-February 2, 2018}, year = {2018}, month = {01/28/2018}, publisher = {Society for Range Management Meeting Proceedings}, address = {Reno, NV}, abstract = {

The 2016 {\textquotedblleft}Ecological Sites for Landscape Management{\textquotedblright} special issue of Rangelands recommended an update to our thinking of Ecological Sites, suggesting that in our desire to make Ecological Sites more quantitative, we abandoned consideration of Ecological Sites{\textquoteright} spatial context. In response, Ecological Site Groups (ESGs) and associated general state-and-transition modelwere proposed as a framework for describing landscape-level processes occurring across multiple ecological sites, and thus integrating multiple ecological sites from similar landscapes into common behavioral units. We hypothesized that the spatial distribution of ESGs could be predicted using readily available geospatial data due to the theoretical association between ESGs and landscape biophysical properties. Here we test ESG concepts with a spatial modeling framework using machine learning algorithms, a SSURGO modified NASIS point dataset, and a suite of remote sensing-based spatial covariates (e.g., hyper-temporal remote sensing, terrain attributes, climate data, land-cover, and lithology). Our modeling approach was tested on two Major Land Resource Area (MLRA) study areas within the western U.S., representing 6.1 million ha within MLRA 35 and 7.5 million ha within MLRA 42. Results show our approach was effective in mapping ESGs, with a 64\% correct classification based on 1,406 point observations across 8 expertly-defined ESG classes in MLRA 35 and a 75\% correct classification based on 2,626 point observations across 9 expertly-defined ESG classes in MLRA 42. National coverage of the training and covariate data used in this pilot study provides opportunities for a consistent national-scale mapping effort of ESGs.

}, author = {S. W. Salley and Jonathan Maynard and Travis Nauman and Curtis Talbot and Joel R. Brown} } @article {JRN54822, title = {Two New Mobile Apps for Rangeland Inventory and Monitoring by Landowners and Land Managers}, journal = {Rangelands }, volume = {32}, year = {2017}, month = {2017}, pages = {46-55}, chapter = {46}, abstract = {

On the Ground

}, keywords = {assessment, inventory, mobile apps, monitoring}, doi = {10.1016/j.rala.2016.12.003}, author = {Jeffrey E. Herrick and Jason W. Karl and Sarah McCord and M. Buenemann and C. Riginos and Ericha Courtright and Justin Van Zee and Amy Ganguli and Angerer, J. and Joel R. Brown and D.W. Kimiti and R. Saltzman and Beh, Adam and Brandon T Bestelmeyer} } @article {JRN54845, title = {Two new mobile apps for rangeland inventory and monitoring by landowners and land managers}, journal = {Rangelands}, volume = {39}, year = {2017}, month = {04/2017}, pages = {46-55}, chapter = {46}, abstract = {

Rangeland inventory and monitoring have been transformed during the past 10 years by a number of major innovations. This paper reviews the status of two new mobile apps (LandInfo and LandCover) that are part of a larger {\textquotedblleft}Land-Potential Knowledge System{\textquotedblright} (LandPKS) that is being developed to capitalize on these four innovations in order to provide the knowledge and information needed to make land use and land management decisions at individual field, pasture, or ecological site scales. It focuses specifically on the opportunities to use these apps to support inventory and monitoring by landowners and land managers. The apps can be used to collect data that is compatible,and in many cases entirely consistent with the BLM{\textquoteright}s Assessment, Inventory and Monitoring, \ and the NRCS{\textquoteright}s National Resources Inventory program. Other featuresinclude one-time data entry and permanent cloud storage on a web portal and data visualization tools.

}, doi = {10.1016/j.rala.2016.12.003}, url = {files/bibliography/17-029.pdf}, author = {Jeffrey E. Herrick and Jason W. Karl and Sarah McCord and M. Buenemann and C. Riginos and Ericha Courtright and Justin Van Zee and Amy Ganguli and Angerer, J. and Joel R. Brown and D.W. Kimiti and R. Saltzman and Beh, Adam and Brandon T Bestelmeyer} } @article {JRN54775, title = {A toolkit for ecosystems ecologists in the time of big science}, journal = {Ecosystems}, volume = {20}, year = {2017}, month = {03/2017}, pages = {259-266}, chapter = {259}, abstract = {

Ecosystems ecologists are being challenged to address the increasingly complex problems that comprise Big Science. These problems include multiple levels of biological organization that cross multiple interacting temporal and spatial scales, from individual plants, animals and microbes to landscapes, continents, and the globe. As technology improves, the availability of data, derived data products, and information to address these complex problems are increasing at finer and coarser scales of resolution, and legacy {\textquotedblleft}dark data{\textquotedblright} are being brought to light. \ Data analytics are improving as {\textquotedblleft}big{\textquotedblright} data increase in importance in other fields that are improving access to these data. \ New data sources (crowd sourcing, social media), and ease of communication and collaboration among ecosystems ecologists and other disciplines are increasingly possible via the internet. It is increasingly important that ecosystems ecologists be able to communicate their findings, and to translate their concepts and findings into concrete {\textquotedblleft}bits{\textquotedblright} of information that a general public can understand. Traditional approaches that portray ecosystem sciences as a dichotomy between empirical research and theoretical research will keep the field from fully contributing to the complexity of global change questions, and will keep ecosystems ecologists from taking full advantage of the data and technology available. Building on previous research, we describe a more forward-looking, integrated empirical-theoretical-modeling approach that is iterative with learning to take advantage of the elements of Big Science. We suggest that training ecosystems ecologists in this integrated approach will be critical to addressing complex Earth system science questions, now and in the future.

}, doi = {10.1007/s10021-016-0072-1}, url = {files/bibliography/16-024.pdf}, author = {Debra C. Peters and Gregory S. Okin} } @conference {JRN54790, title = {Targeted livestock grazing to improve and restore rangelands}, booktitle = {52nd Annual Congress of the Grassland Society of Southern Africa}, year = {2017}, month = {07/2017}, publisher = {52nd Annual Congress of the Grassland Society of Southern Africa}, organization = {52nd Annual Congress of the Grassland Society of Southern Africa}, address = {Mpumalanga-Limpopo Border, South Africa}, abstract = {

Targeted grazing is the application of a specific kind of livestock at the appropriate season, duration, and intensity to accomplish defined vegetation or landscape goals. Grazing by wild and domestic animals is a powerful natural force working in all ecosystems. The ability of selective herbivory to shape plant communities was recognized early in the history of range management when plants were classified as increasers and decreasers, which indicated changes in their prevalence in plant communities in response to grazing. Along with fire, grazing is the oldest vegetation management tool. Knowledge of selective grazing habits of livestock and of how grazing influences vegetation communities can be used to address contemporary land management challenges, such as suppressing invasive exotic weeds on rangelands, reducing fire risk in the wildland-urban interface, and finding chemical-free ways to control weeds in organic agriculture. The major difference between good grazing management and targeted grazing is that targeted grazing refocuses outputs of grazing from livestock production to vegetation and landscape enhancement. Targeted grazing should be considered as another tool in the kit for constructing desirable ecosystems. It can and should be used in combination with other technologies, such as prescribed fire, mechanical or herbicide treatments, and seeding. The most important skill for people applying targeted grazing for vegetation management is patience and commitment. The effects of correctly applied targeted grazing are generally slow and cumulative. A minimum of three years is usually required before noticeable differences in perennial herbaceous composition become apparent. Browse may take much longer. A successful grazing prescription for vegetation management should: 1) cause significant damage to the target plant; 2) minimize adverse impact to the surrounding desirable vegetation; and 3) be integrated with other control methods as part of an overall landscape management strategy. A clear understanding of the palatability and effect of defoliation of all plants in the community is needed to design a grazing strategy that will compromise the target plants and benefit the desired plants. The challenge is to select the correct animal, grazing time, and grazing intensity to maximize damage to target plants or defoliation level of target location and minimize adverse effects on the surrounding desirable vegetation without compromising the animal{\textquoteright}s welfare. Vegetation management and landscape enhancement strategies must be ecologically based with careful attention to positively directing community change, not just suppressing an undesired species. Using grazing animals to purposely enhance rangeland landscapes is a viable approach because livestock grazing is already the dominant use of rangelands and may be as simple as switching to the appropriate livestock species for the current botanical composition of the land. Examples of successful application of targeted grazing will be provided.Targeted grazing is the application of a specific kind of livestock at the appropriate season, duration, and intensity to accomplish defined vegetation or landscape goals. Grazing by wild and domestic animals is a powerful natural force working in all ecosystems. The ability of selective herbivory to shape plant communities was recognized early in the history of range management when plants were classified as increasers and decreasers, which indicated changes in their prevalence in plant communities in response to grazing. Along with fire, grazing is the oldest vegetation management tool. Knowledge of selective grazing habits of livestock and of how grazing influences vegetation communities can be used to address contemporary land management challenges, such as suppressing invasive exotic weeds on rangelands, reducing fire risk in the wildland-urban interface, and finding chemical-free ways to control weeds in organic agriculture. The major difference between good grazing management and targeted grazing is that targeted grazing refocuses outputs of grazing from livestock production to vegetation and landscape enhancement. Targeted grazing should be considered as another tool in the kit for constructing desirable ecosystems. It can and should be used in combination with other technologies, such as prescribed fire, mechanical or herbicide treatments, and seeding. The most important skill for people applying targeted grazing for vegetation management is patience and commitment. The effects of correctly applied targeted grazing are generally slow and cumulative. A minimum of three years is usually required before noticeable differences in perennial herbaceous composition become apparent. Browse may take much longer. A successful grazing prescription for vegetation management should: 1) cause significant damage to the target plant; 2) minimize adverse impact to the surrounding desirable vegetation; and 3) be integrated with other control methods as part of an overall landscape management strategy. A clear understanding of the palatability and effect of defoliation of all plants in the community is needed to design a grazing strategy that will compromise the target plants and benefit the desired plants. The challenge is to select the correct animal, grazing time, and grazing intensity to maximize damage to target plants or defoliation level of target location and minimize adverse effects on the surrounding desirable vegetation without compromising the animal{\textquoteright}s welfare. Vegetation management and landscape enhancement strategies must be ecologically based with careful attention to positively directing community change, not just suppressing an undesired species. Using grazing animals to purposely enhance rangeland landscapes is a viable approach because livestock grazing is already the dominant use of rangelands and may be as simple as switching to the appropriate livestock species for the current botanical composition of the land. Examples of successful application of targeted grazing will be provided.

}, author = {J.W. Walker and C. Donovan Bailey and Launchbaugh, K.L. and Fraker-Marble, M and John Hendrickson and J. C. Mosley and Burritt, B and Richard E. Estell and M. Horney and Andr{\'e}s F. Cibils} } @conference {JRN54647, title = {Tipping points in rangeland social-ecological systems of the Southwest US: Past and present}, booktitle = {Ecological Society of America}, year = {2016}, month = {08/2016}, publisher = {Ecological Society of America Abstracts}, organization = {Ecological Society of America Abstracts}, address = {Fort Lauderdale, FL}, abstract = {
Background/Question/Methods: \ The advent of social-ecological system perspectives has led to new questions about the causes and consequences of global change. Nearly all research in rangeland ecosystems of the U.S. has focused on transitions in vegetation (such as grasslands to shrublands) casting human activities (especially livestock production) as an external driver of change. Here, we consider abrupt change in Southwestern rangelands from a social-ecological systems perspective. We consider the theory that abrupt changes in societal organization and environment are due to changes in multiple slow variables, including social factors, government policy, markets, and technology, interacting with abrupt {\textquotedblleft}trigger{\textquotedblright} events, especially drought, that leads to acute limitations and longer-term reductions of perennial grass forage. We draw upon a number of data sources to characterize and explain social-ecological transitions over the last 160 years in southwestern New Mexico, and offer predictions about the next transition.
Results/Conclusions: In the late 1800s, government policies to encourage settlement as well as access to foreign capital, alongside the proliferation of railroads and water developments, led to a rapid increase in livestock numbers and large cattle ranches (transition 1). Subsequent multi-year droughts and overstocking led to catastrophic livestock losses, reductions of perennial grass cover, and new government policies that promoted a transition to smaller ranching enterprises in the 1930s (transition 2). Since that time, severe droughts have led to additional loss of perennial grasslands and gradual shrub encroachment, alongside increased urbanization and recognition of environmental degradation. Recent livestock numbers are considerably lower than carrying capacities estimated in the mid-20th century. Ranch ownership has been unstable in the least favorable landscapes, associated with only patchy ongoing reduction of perennial grass cover. Predicted declines in regional water balance and increased interannual precipitation variability will again accelerate loss of perennial grasses, increase dominance by unpalatable shrubs, and reduce availability of harvested forages (hay) necessary for sustaining small-scale ranching operations. We predict that the next social-ecological transition will involve 1) the dissolution of some small ranching enterprises and aggregation of private and leased land into larger, corporate operations that may not emphasize livestock production, 2) increased use of public lands for renewable energy production and wilderness, and possibly the reorganization of public land leasing strategies, 3) the transformation of most remaining grassland areas to shrublands, and 4) the potential for greatly increased wind erosion rates and declining air quality for urban centers.
}, author = {Brandon T Bestelmeyer and Kris Havstad and O. E. Sala and N. F. Sayre and Nicholas Webb} } @article {JRN54598, title = {A toolkit for ecosystem ecologists in the time of Big Science}, journal = {Ecosystems}, year = {2016}, abstract = {

Ecosystem ecologists are being challenged to address the increasingly complex problems that comprise Big Science. These problems include multiple levels of biological organization that cross multiple interacting temporal and spatial scales, from individual plants, animals, and microbes to landscapes, continents, and the globe. As technology improves, the availability of data, derived data products, and information to address these complex problems are increasing at finer and coarser scales of resolution, and legacy, dark data are brought to light. Data analytics are improving as big data increase in importance in other fields that are improving access to these data. New data sources (crowdsourcing, social media) and ease of communication and collaboration among ecosystem ecologists and other disciplines are increasingly possible via the internet. It is increasingly important that ecosystem ecologists be able to communicate their findings, and to translate their concepts and findings into concrete bits of information that a general public can understand. Traditional approaches that portray ecosystem sciences as a dichotomy between empirical research and theoretical research will keep the field from fully contributing to the complexity of global change questions, and will keep ecosystem ecologists from taking full advantage of the data and technology available. Building on previous research, we describe a more forward-looking, integrated empirical{\textendash} theoretical modeling approach that is iterative with learning to take advantage of the elements of Big Science. We suggest that training ecosystem ecologists in this integrated approach will be critical to addressing complex Earth system science questions, now and in the future.

}, keywords = {analytics, big data, crowdsourcing, interacting spatial and temporal scales, machine learning, multiple levels of organization, technological advances}, doi = {10.1007/s10021-016-0072-1}, url = {files/bibliography/JRN00645.pdf}, author = {Debra C. Peters and Gregory S. Okin} } @article {JRN54495, title = {Threshold wind velocity dynamics as a driver of aeolian sediment mass flux}, journal = {Aeolian Research}, volume = {20}, year = {2016}, month = {03/2016}, pages = {45-59}, chapter = {45}, abstract = {

Horizontal (saltation) mass flux is a key driver of aeolian dust emission. Estimates of the horizontal mass flux underpin assessments of the global dust budget and influence our understanding of the dust cycle and its interactions. Current equations for predicting horizontal mass flux are based on limited field data and are constrained to representing transport-limited equilibrium saltation, driven by the wind momentum flux in excess of an entrainment threshold. This can result in large overestimation of the sediment mass flux. Here we compare measurements of the soil entrainment threshold, horizontal mass flux, and their temporal variability for five undisturbed dryland soils to explore the role of threshold in controlling the magnitude of the mass flux. Average and median entrainment threshold showed relatively small variability among sites and relatively small variability between seasons, despite significant differences in soil surface conditions. Physical and biological soil crusts had little effect on the threshold value, and threshold appeared to play a minor role in determining the magnitude of the mass flux. Our results suggest that horizontal mass flux was controlled more by the supply limitation and abrasion efficiency of saltators present as loose erodible material or originating from neighboring soil sources. The omission of sediment supply and explicit representation of saltation bombardment from horizontal flux equations is inconsistent with the process representation in dust emission schemes and contributes to uncertainty in model predictions. This uncertainty can be reduced by developing greater process fidelity in models to predict horizontal mass flux under both supply- and transport-limited conditions.

}, keywords = {dust, erodibility, supply limitation, transport sediment flux, wind erosion}, doi = {10.1016/j.aeolia.2015.11.006}, url = {/files/bibliography/16-002.pdf}, author = {Nicholas Webb and Magda Galloza and Teddy M. Zobeck and Jeffrey E. Herrick} } @conference {JRN54414, title = {Tools for adaptation and mitigation of climate change on southwestern working-lands}, booktitle = {New Mexico Water Conference}, year = {2015}, month = {10/2015}, address = {Taos, NM}, abstract = {

In February 2014, the USDA established 7 Hubs and 3 Sub Hubs across the nation to assist farmers, ranchers and foresters in adapting to the effects of climate change. Specific vulnerabilities related to projected climatic changes in the Southwest (SW) include water scarcity, the effects of elevated temperatures on livestock production and regional cropping systems and elevated wildfire risk. In the first 18 months, the SW Climate Hub initiated projects and programs to help New Mexico farmers and ranchers adapt to climate change. The Climate Hub Tool Shed provides information on tools that can assist agricultural and forest land managers in adapting to climate variability and change. The SW Hub launched several projects to translate scientific information and reach the public such as 1) authoring of a vulnerability assessment of southwestern working lands to climate change, 2) partnering with Cooperative Extension Service to host landowner workshops on climate change and 3) supporting education of future generations via a climate change - water cycle educational module, tailored to the SW, comprised of 10 one-hour lessons. To reach a broad audience, the SW Hub hosts a website, provides a monthly bulletin, partners with sister federal climate change programs and convenes sessions at scientific meetings.

}, author = {Emile H. Elias and A. Rango and Caitriana Steele and Kris Havstad and Joel R. Brown and Ryann Smith} } @conference {JRN54437, title = {The temporal dimension of regime shifts: How long can ecosystems operate beyond critical thresholds before transitions become irreversible?}, booktitle = {100th Annual Meeting of the Ecological Society of America}, year = {2015}, month = {08/2015}, address = {Baltimore, MD}, abstract = {

Background/Question/Methods: Ecosystem thresholds are often identified by observing or inducing slow changes in different driver variables and investigating changes in the asymptotic state of the system, such as the response of lakes to nutrient loading or biome responses to climate change. Yet many anthropogenic pressures on ecosystems change rapidly or in discrete steps. Moreover, once an ecosystem crosses a bi-furcation point in the equilibrium states of the system, the transition is often assumed to be irreversible, but such irreversibility is rarely assessed. We tested these assumptions, investigating the temporal dimension of critical thresholds and the reversibility of slowly evolving dynamical systems responding to abrupt changes in external drivers. This study asks if and how long ecosystems can operate beyond a threshold {\textendash}a bi-furcation point{\textemdash}before they they become trapped in an alternative state. We use two approaches: 1) simulation models; and 2) long-term experiments that pushed semi-arid grasslands and mesic grasslands past critical thresholds and then relaxed these pressures in some plots to test for reversibility.

Results/Conclusions: The simulated ecosystems, ecosystems or patches ecosystems remain trapped a new regime when the duration of forcing exceeds a threshold. However, some patches can operate beyond a bi-furcation point for years to decades before relaxing global change pressures fails to restore the original ecosystem state. Weaker exogenous forcing and lower endogenous resilience led to longer transient dynamics. Long-term experiments were consistent with this framework. After experimental cessation of N-addition, grazing, or fire suppression, many grasslands patches returned to their initial state, but the most altered patches of have yet to recover 5 to 20 years later after relaxing exogenous forcing. These responses support the argument that some real-world ecosystems can be restored even if they were pushed beyond thresholds that would eventually lead to irreversible shifts. We propose that ecosystem thresholds in slower systems have two dimensions: regime shifts occur when global change crosses a threshold defined by both magnitude\ and\ duration of exogenous forcing. An important implication of these results is that ecosystems that have yet to cross temporal thresholds may still be restored by appropriate and targeted management actions. Leveraging this capacity requires new tools to indicate when ecosystems are in an unstable state following press perturbations.\  Abstract $\#$ COS 75-8.

}, author = {Ratajczak, Zak and S.L. Collins and Paolo D{\textquoteright}Odorico and Jesse Nippert and Isbell, Forest and Brandon T Bestelmeyer} } @conference {JRN54415, title = {Thin scale ecohydrological data and relations at semi-arid regions: a methodological approach}, booktitle = {New Mexico Water Conference}, year = {2015}, month = {10/2015}, address = {Taos, NM}, abstract = {

In semi-arid regions worldwide the vegetation is organized in patches surrounded by bare soil with marked differences in their soil properties that play important roles in runoff and infiltration.\  Chihuahuan-Sonoran and Patagonian Monte\  deserts regions show floristic similarity greater than that expected from the geographical barriers between them.\  These\  very similar environments (Logan, 1968; McGinnies, 1968, 1979; Walter, 1971) can ease comparisons of hydrological plot scale estimates obtained at the Patagonian Monte by Rossi and Ares (2012), with observations on composite overland flow) on runoff plots in the Chihuahuan desert(USA). We propose a methodology that focuses on generating thin scale eco-hydrological data and relations at the Chihuahuan desert to compare them with estimates obtained at the Patagonian Monte

}, author = {M. J. Rossi and Jorge Ares and Alexander Fernald and A. Rango and Emile H. Elias} } @article {JRN54389, title = {A tribute to Michael R. Raupach for contributions to aeolian fluid dynamics}, journal = {Aeolian Research}, volume = {19}, year = {2015}, month = {10/2015}, pages = {37-54}, chapter = {37}, abstract = {

Since the early work of Bagnold in the 1940s, aeolian research has grown to become a major integral part of earth-system studies. Many individuals have contributed to this development, and Dr. Michael R. Raupach (MR2, 1950 {\textendash} 2015) was one of the most outstanding. MR2 worked for about a decade (1985 {\textendash} 1995) intensively on wind erosion problems, but he did so brilliantly by relating aeolian problems to his deep knowledge of turbulence, and made profound contributions to the field with far-reaching influences and a lasting legacy. The beauty of MR2s work is crystal clear conceptual thinking, reducing problems to their essentials and expressing that essence with elegance yet simplicity. The results of his work are robust and practically applicable. In this review we reflect on MR2{\textquoteright}s contribution to a number of important aeolian research themes, summarize the developments since his inspirational work and place MR2{\textquoteright}s effort in the context of aeolian science. We also demonstrate how MR2{\textquoteright}s work provided the foundations for many of the new developments in aeolian new research. In this tribute, we concentrate on MR2{\textquoteright}s work in five areas: (1) drag partition theory; (2) saltation roughness length; (3) saltation bombardment; (4) threshold friction velocity; and (5) carbon cycle.

}, keywords = {carbon cycle, Drag partition, dust emission, Michael R. Raupach, roughness, threshold friction velocity}, doi = {10.1016/j.aeolia.2015.09.004}, url = {/files/bibliography/15-018.pdf}, author = {Shao, Yaping and William Nickling and Gilles Bergametti and Harry Butler and A. Chappell and Findlater, Paul and J. Gillies and Ishizuka, Masahide and Martina Klose and Kok, Jasper F. and John Leys and Lu, Hau and B{\'e}atrice Marticorena and Grant McTainish and McKenna-Neuman, Cheryl and Gregory S. Okin and Craig Strong and Nicholas Webb} } @article {JRN53928, title = {Taking the pulse of a continent: Expanding site-based research infrastructure for regional- to continental-scale ecology}, journal = {Ecosphere}, volume = {5}, year = {2014}, month = {03/2014}, chapter = {Article 29}, abstract = {

Many of the most dramatic and surprising effects of global change on ecological systems will occur across large spatial extents, from regions to continents. Multiple ecosystem types will be impacted across a range of interacting spatial and temporal scales. The ability of ecologists to understand and predict these dynamics depends, in large part, on existing site-based research infrastructures that were developed in response to historic events. Here we review how unevenly prepared ecologists are, and more generally, ecology is as a discipline, to address continental-scale questions given these pre-existing site-based capacities, and we describe the changes that will be needed to effectively pursue these broad-scale questions in the future. We first review the types of approaches commonly used to address questions at broad scales, and identify the research, cyber-infrastructure, and cultural challenges associated with these approaches. These challenges include developing a detailed, mechanistic understanding of the drivers and responses of ecosystem dynamics across a large, diverse geographic extent. Measurements of fluxes or flows of materials, energy or information across levels of biological organization or spatial units are challenging for the mosaic of natural and human-dominated ecosystems found across large spatial extents. The diversity of methods, sampling protocols, and data acquisition technologies make post-hoc comparisons of ecosystems using existing data challenging, and data collected using standardized methods across sites require coordination and teamwork. Sharing of data and analytics to create derived data products are needed for multi-site studies, but this level of collaboration is not part of the current ecological culture. We then discuss the strengths and limitations of current site-based research infrastructures in meeting these challenges, and describe a path forward for continental-scale ecological research that integrates existing infrastructures with emerging technologies to more effectively address broad-scale questions.

}, keywords = {connectivity, cyber-infrastructure, data interoperability, ecological culture, ecological networks, macro-ecology, open science}, doi = {10.1890/ES13-00295.1}, url = {/files/bibliography/14-003.pdf}, author = {Debra C. Peters and Loescher, H.W. and M.D. San Clements and Kris Havstad} } @article {49838, title = {A test of critical thresholds and their indicators in a desertification-prone ecosystem: more resilience than we thought}, journal = {Ecology Letters}, volume = {16}, year = {2013}, month = {01/2013}, pages = {339-345}, chapter = {339}, abstract = {

Theoretical models predict that drylands can cross critical thresholds, but experimental manipulations to evaluate them are non-existent. We used a long-term (13-year) pulse-perturbation experiment featuring heavy grazing and shrub removal to determine if critical thresholds and their determinants can be demonstrated in Chihuahuan Desert grasslands. We asked if cover values or patch-size metrics could predict vegetation recovery, supporting their use as early-warning indicators. We found that season of grazing, but not the presence of competing shrubs, mediated the severity of grazing impacts on dominant grasses. Recovery occurred at the same rate irrespective of grazing history, suggesting that critical thresholds were not crossed, even at low cover levels. Grass cover, but not patch size metrics, predicted variation in recovery rates. Some transition-prone ecosystems are surprisingly resilient; management of grazing impacts and simple cover measurements can be used to avert undesired transitions and initiate restoration.

}, keywords = {desertification, early warning, grazing, long-term experiment, patch size, regime shift, resilience, state-transition model}, doi = {10.1111/ele.12045}, url = {/files/bibliography/13-005.pdf}, author = {Brandon T Bestelmeyer and Danielle Duni and D. K. James and Laura M. Burkett and Kris Havstad} } @article {JRN54847, title = {Tree effects on grass growth in savannas: competition, facilitation and the stress-gradient hypothesis}, journal = {Journal of Ecology}, volume = {101}, year = {2013}, pages = {202-209}, abstract = {

1. The stress-gradient hypothesis (SGH) predicts an increasing importance of facilitative mechanisms relative to competition along gradients of increasing environmental stress. Although developed across a variety of ecosystems, the SGH{\textquoteright}s relevance to the dynamic tree{\textendash}grass systems of global savannas remains unclear. Here, we present a meta-analysis of empirical studies to explore emergent patterns of tree{\textendash}grass relationships in global savannas in the context of the SGH.
2. We quantified the net effect of trees on understorey grass production relative to production away from tree canopies along a rainfall gradient in tropical and temperate savannas and compared these findings to the predictions of the SGH. We also analysed soil and plant nutrient concentrations in subcanopy and open-grassland areas to investigate the potential role of nutrients in determining grass production in the presence and absence of trees.
3. Our meta-analysis revealed a shift from net competitive to net facilitative effects of trees on subcanopy grass production with decreasing annual precipitation, consistent with the SGH. We also found a significant difference between sites from Africa and North America, suggesting differences in tree{\textendash}grass interactions in the savannas of tropical and temperate regions.
4. Nutrient analyses indicate no change in nutrient ratios along the rainfall gradient, but consistent nutrient enrichment under tree canopies.
5. Synthesis. Our results help to resolve questions about the SGH in semi-arid systems, demonstrating that in mixed tree{\textendash}grass systems, trees facilitate grass growth in drier regions and suppress grass growth in wetter regions. Relationships differ, however, between African and North American sites representing tropical and temperate bioclimates, respectively. The results of this meta-analysis advance our understanding of tree{\textendash}grass interactions in savannas and contribute a valuable data set to the developing theory behind the SGH.

}, keywords = {Africa, competition, facilitation, hypothesis, North America, plant{\textendash}plant interactions, rainfall gradient, savanna, stress-gradient hypothesis, tree{\textendash}grass interactions}, doi = {10.1111/1365-2745.12010}, url = {files/bibliography/JRN00619.pdf}, author = {Dohn, Justin and Demb{\'e}l{\'e}, Fadiala and Karemb{\'e}, Moussa and Moustakas, Aristides and Am{\'e}vor, Kosiwa A. and Niall Hanan} } @article {49848, title = {Temperature drives the continental-scale distribution of key microbes in topsoil communities}, journal = {Science}, volume = {340}, year = {2013}, pages = {1574-1577}, abstract = {

Global warming will likely force terrestrial plant and animal species to migrate toward cooler areas or sustain range losses; whether this is also true for microorganisms remains unknown. Through continental-scale compositional surveys of soil crust microbial communities across arid North America, we observed a latitudinal replacement in dominance between two key topsoil cyanobacteria that was driven largely by temperature. The responses to temperature of enrichment cultures and cultivated strains support this contention, with one cyanobacterium (Microcoleus vaginatus) being more psychrotolerant and less thermotolerant than the other (M. steenstrupii). In view of our data and regional climate predictions, the latter cyanobacterium may replace the former in much of the studied area within the next few decades, with unknown ecological consequences for soil fertility and erodibility.

}, keywords = {arid North America, climate change, cyanobacteria, global warming, microbial communities, soil erosion, soil fertility}, doi = {10.1126/science.1236404}, url = {files/bibliography/JRN49848.pdf}, author = {Ferran Garcia-Pichel and Loza, Virginia and Marusenko, Yevgeniy and Mateo, Pilar and Potrafka, Ruth M.} } @article {JRN54622, title = {A Technique for Estimating Rangeland Canopy-Gap Size Distributions From High-Resolution Digital Imagery}, journal = {Rangeland Ecology \& Management}, volume = {65}, year = {2012}, month = {01/2012}, pages = {196 - 207}, chapter = {196}, abstract = {

The amount and distribution of gaps in vegetation canopy is a useful indicator of multiple ecosystem processes and functions. In this paper, we describe a semiautomated approach for estimating canopy-gap size distributions in rangelands from high-resolution (HR) digital images using image interpretation by observers and statistical image classification techniques. We considered two different classification methods (maximum-likelihood classification and logistic regression) and both pixel-based and object-based approaches to estimate canopy-gap size distributions from 2- to 3-cm resolution UltraCamX color infrared aerial photographs for arid and semiarid shrub sites in Idaho, Nevada, and New Mexico. We compare our image-based estimates to field-based measurements for the study sites. Generally, percent of input points correctly classified and kappa coefficients of agreement for plot image classifications was very high. Plots with low kappa values yielded canopy gap estimates that were very different from field-based estimates. We found a strong relationship (R2 \> 0.9 for all four methods evaluated) between image- and field-based estimates of the total percent of the plot in canopy gaps greater than 50\ cm for plots with a classification kappa of greater than 0.5. Performance of the remote sensing techniques varied for small canopy gaps (25 to 50\ cm) but were very similar for moderate (50 to 200\ cm) and large (\> 200\ cm) canopy gaps. Our results demonstrate that canopy-gap size distributions can be reliably estimated from HR imagery in a variety of plant community types. Additionally, we suggest that classification goodness-of-fit measures are a potentially useful tool for identifying and screening out plots where precision of estimates from imagery may be low. We conclude that classification of HR imagery based on observer-interpreted training points and image classification is a viable technique for estimating canopy gap size distributions. Our results are consistent with other research that has looked at the ability to derive monitoring indicators from HR imagery.

}, keywords = {digital aerial phtoography, image classification, photo interpretations, remote sensing}, issn = {15507424}, doi = {10.2111/REM-D-11-00006.1}, url = {/files/bibliography/12-043.pdf}, author = {Jason W. Karl and Danielle Duni and Scott T. Schrader} } @proceedings {JRN54550, title = {Terpene profile of one-seed juniper saplings explains differential herbivory by small ruminants}, volume = {p. 30}, year = {2012}, month = {05/2012}, publisher = {Wildland Shrub Symposium}, address = {Las Cruces, NM}, abstract = {A study was conducted in central New Mexico to examine the relationship between terpene profile and one-seed juniper sapling herbivory by sheep and goats. Fifteen does (47.9 {\textpm} 1.1 kg) and four ewes (69.2 {\textpm} 0.9 kg) were allotted to 16 paddocks (20 x 30m) for 6 days in summer 2006 and spring 2007. Leaves and twigs from 311 browsed saplings (small [< 0.5 m], medium [0.5-1.0 m] or tall [>1.0 m] saplings that received low [< 33\%], moderate [33-66\%] or heavy [> 66\%] herbivory) were collected the same day they were browsed and stored for chemical analysis. The terpene profile contained a total of 66 compounds that included a diverse set of hydrocarbon and oxygenated mono- and sesquiterpenes and a few diterpenes. Total terpene concentration was higher (P < 0.001) in spring (20.6 {\textpm} 0.5 mg/g; mean {\textpm} SE) than summer (16.7 {\textpm} 0.3 mg/g), lower (P < 0.001) in small saplings (16.5 {\textpm} 0.6 mg/g) compared to medium (19.8 {\textpm} 0.4 mg/g) and tall (19.5 {\textpm} 0.4 mg/g) saplings and lower (P < 0.001) in heavily defoliated saplings (16.1 {\textpm} 0.4 mg/g) vs. moderately (18.7 {\textpm} 0.5 mg/g) or lightly (21.2 {\textpm} 0.6 mg/g) browsed counterparts. A subset of 14 compounds ([E]-{\ss}-farnesene, cis-sabinene hydrate, bornyl acetate, {\textquoteright}-eudesmol, germacrene A, cis-piperitol, cis-p-menth-2-en-1-ol, trans-piperitol acetate + terpin-4-ol acetate, [Z]-{\ss}-ocimene, terpin-4-ol, camphene hydrate, a-humelene, 8-a-11-elemodiol, {\ss}-elemene), most of which occurred at relatively low concentrations, explained 45\% of sapling discrimination (P < 0.001) into high, moderate and low herbivory categories. Results support the hypothesis that one-seed juniper terpene chemistry is related to the extent of sapling herbivory by small ruminants, sapling size, and season.}, author = {S. A. Utsumi and Andr{\'e}s F. Cibils and Richard E. Estell} } @conference {JRN54587, title = {Towards broad-scale perspectives on landscape dynamics: The National Ecological Dynamics Database}, booktitle = {Society for Range Management, 65th Annual Meeting}, year = {2012}, month = {10/2011}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Spokane, WA}, abstract = {Ecological site descriptions (ESDs) are a useful technology for conveying the ecological potential of specific land types and the possible responses of vegetation and soils on them to management. Yet some of the same traits that lend ESDs their management utility (e.g., narrative format and site-specific focus) also make them an inefficient resource for broader-scaled analyses, such as comparing ecological processes among regions or producing national maps of conservation needs. Such objectives would be better served by a database in which ecological information for a region can be (1) readily queried and (2) easily analyzed in a geographic information system. To help address this need, we have initiated development of a National Ecological Dynamics Database (NEDD), which aims to identify and describe ecological dynamics of primary management concern at the level of Major Land Resource Areas. This database will catalog information pertinent to such dynamics in a relational geodatabase format. The core objectives of the NEDD are to (1) promote nationwide consistency in ESD development and (2) provide a national view of potential ecological states (in the sense applied to state-and-transition models), their dynamics, restoration successes and failures, and the factors determining the patterns and types of ecological change observed at landscape to continental scales. As a first step in designing and populating the NEDD, data are being harvested from ESDs currently available. Here, we present insights from this initial exercise and describe in more detail the background, goals, design, and expected utility of this new database.}, author = {Jebediah C. Williamson and Brandon T Bestelmeyer} } @proceedings {49920, title = {Tools to study and manage grazing behavior at multiple scales to enhance the sustainability of livestock production systems}, volume = {IX}, year = {2011}, month = {04/2011}, pages = {559-564}, publisher = {International Rangeland Congress}, address = {Rosario, Argentina}, abstract = {

Key points

1. A {\textquotedblleft}single tool{\textquotedblright} for studying free-ranging animal behavior on complex landscapes does not exist.

2. Today{\textquoteright}s tools require competent multiple disciplinary teams beginning with the planning and design of experiments on through to applying the results within a practical management framework.

3. Research that involves instrumenting animals must be conducted in a human manner that accurately measures and or manages the phenomenon in question.

4. Using innate animal behaviors to accomplish management goals by melding biology with electronics to optimize ecological and labor efficiency is the future and virtual fencing will soon be one of the tools.

Introduction: Tracking animals is not new, early hunters practiced it for survival (Liebenberg, 2006); however, today it is practiced in the name of science and what the future holds will be new (Etcgroup., 2004). The phrase {\textquotedblleft}if you can measure it, you can manage it{\textquotedblright} may have first been used in the health care industry (Kinex IHA Corp., 2000). Nevertheless, this axiom is pivotal to range animal ecology involving measuring and managing free-ranging animal distribution, a central tenant of grazing management (Bailey and Brown, 2011). Free-ranging livestock neither use all the space made available to them (Anderson et al., 2003; Rinella et al., 2011) nor do they use it in a random manner (Anderson et al, 2011a). Over 68 factors (Anderson, 2010) including magnetism(Begall et al., 2008) appear to impact landscape use by free-ranging animals. Thus understanding the process of foraging is challenging and may require research programs that de-emphasize traditional methods (Laca, 2009).

}, keywords = {bio-logging, GPS, telemetry, virtual fencing}, url = {/files/bibliography/11-018.pdf}, author = {D.M. Anderson} } @article {49927, title = {Transfer and incorporation of heritable symbiotic fungi into non-host plants}, number = {60706648}, year = {2011}, month = {March 8, 2011}, address = {United States}, abstract = { A first plant species or a part thereof may be produced which has stably and heritably integrated therein one or more endophytic fungi which are derived from a second, different plant species. This first plant species is not a host plant for the endophytic fungi in nature. These resultant first plant species containing the endophytic fungi exhibit substantially increased vigor, altered morphology and chemistry, and increased reproductive potential compared to non-treated controls.}, url = {http://patents.com/us-7901927.html}, author = {J.R. Barrow and M.E. Lucero} } @article {49936, title = {Temporal dynamics of shrub proliferation: Linking patches to landscapes}, journal = {International Journal of Geographical Information Science}, volume = {25}, year = {2011}, month = {08/2011}, pages = {913-930}, chapter = {913}, abstract = {Shifts in vegetation composition and cover are generally characterized by processes acting at different levels such as landscapes, hill slopes, or plant interspaces. Object-oriented analytical approaches are based upon the inherently hierarchical nature of complex systems and are well-suited to research applications conducted at a range of spatial scales. We quantified long-term vegetation dynamics from two perspectives (i.e., landscape and vegetation patches) in a Chihuahuan Desert ecosystem in southern New Mexico, U.S.A. from 1937 to 2008. Our multi-scale approach comprised object-based analysis of time series aerial photography with automated image analysis at the landscape scale and manual delineation of shrub image objects at the patch scale. We sought to identify mechanisms associated with changes in shrub patch density and percent cover by classifying the fate of individual shrub patches from one image to the next in the time series. The classification scheme captured colonization by new shrub patches, growth or decline in patch area, and patch stability (i.e., change in size of less than 15\%). Patch growth was categorized as growth by coalescence with neighboring patches or canopy expansion. Similarly, patch decline was distinguished as either loss of patch area due to fragmentation of conglomerate patches or canopy die-back. Interpretations of change in patch density based solely on shrub establishment and mortality can be too simplistic. Increases in patch density can result from an influx of new patches or fragmentation of patches into its constituent patches; conversely, decreases in density may be due to mortality of patches or coalescence of existing patches. We illustrate that patches grew in size at the beginning of the study period in conjunction with increases in shrub cover (0.5\% in 1937 to 11\% in 1960) and patch density (4 patches ha-1 in 1937 to 80 patches ha-1 in 1960) increased during the initial encroachment phase of shrub proliferation. Shrub cover remained stable at 7\% from 1967 to 1989 and over this period, patch dynamics were broadly characterized by maintenance of patch area with roughly equal proportions of mortality and establishment. Shrub cover increased linearly from 8\% in 1989 to 14\% in 2008, approaching a maximum projected shrub cover of 18\% based on mean annual precipitation of 230 mm from Sankaran et al. (2005). Shrub patch fate over this period constituted growth and maintenance of patch area whereas appearance of new patches remained relatively stable. Patch dynamics signify a shifting mosaic in which shrub patch establishment, growth, and mortality wax and wane. Monitoring patch dynamics will become increasingly important in these actively managed ecosystems as broad-scale measures of percent cover approach and fluctuate about a dynamic equilibrium.}, keywords = {cross-scale analysis, hill slopes, landscapes, object-oriented classification, patches dynamics, plant interspaces, proliferation, shrub encroachment}, doi = {10.1080/13658816.2010.498789}, url = {/files/bibliography/11-020.pdf}, author = {Dawn M. Browning and Andrea S. Laliberte and A. Rango} } @proceedings {JRN54544, title = {A technique for estimating rangeland canopy-gap size distributions from high resolution digital imagery}, volume = {p. 0255}, year = {2011}, month = {01/2012}, publisher = {Society for Range Management}, address = {Spokane, Washington}, abstract = {The amount and distribution of gaps in vegetation canopy is a useful indicator of multiple ecosystem processes and functions. We describe a semi-automated approach for estimating canopy-gap size distributions in rangelands from high-resolution (HR) digital images using image interpretation by observers and statistical image classification techniques. We considered two different classification methods (maximum-likelihood classification and logistic regression) and both pixel-based and objectbased approaches to estimate canopy-gap size distributions from 2-3cm resolution color infrared aerial photographs for arid and semi-arid shrub sites in Idaho, Nevada, and New Mexico. We compare our image-based estimates to field-based measurements for the study sites. We found a strong relationship (R2 > 0.9 for all four methods evaluated) between image- and field-based estimates of the total percent of the plot in canopy gaps greater than 50cm for plots with a classification kappa of greater than 0.5. Performance of the four remote sensing techniques varied for small canopy gaps (25 to 50cm), but were very similar for moderate (50 to 200cm) and large (>200cm) canopy gaps. Our results demonstrate that canopy-gap size distributions can be reliably estimated from HR imagery in a variety of plant community types. Additionally, we suggest that classification goodness-of-fit measures are a potentially useful tool for identifying and screening out plots where precision of estimates from imagery may be low. Our results are consistent with other research that has looked at the ability to derive monitoring indicators from HR imagery.}, author = {Jason W. Karl and Danielle Duni and Scott T. Schrader} } @article {49949, title = {Turning information into knowledge for rangeland management}, journal = {Rangelands}, volume = {33}, year = {2011}, month = {08/2011}, pages = {3-5}, chapter = {3}, abstract = {The kind of knowledge system that will be capable of meeting the needs of rangeland managers will evolve as scientists, technology specialists, managers, and biologists find ways to integrate the ever expanding array of information systems and tools to meet their needs. The tools and techniques highlighted in this issue of Rangelands were selected because they have immediate application, and illustrate the various types of tools necessary to support management decision making. The challenge is figuring out how to combine such new tools and knowledge sources in a way that increases understanding of rangeland systems and promotes good decision making.}, doi = {10.2111/1551-501x-33.4.3}, url = {/files/bibliography/11-022.pdf}, author = {Jason W. Karl} } @article {JRN54623, title = {Tribal and state ecosystem management regimes influence forest regeneration}, journal = {Forest Ecology and Management}, volume = {260}, year = {2010}, month = {01/2010}, pages = {734 - 743}, chapter = {734}, abstract = {

The amount and distribution of gaps in vegetation canopy is a useful indicator of multiple Wild ungulates such as white-tailed deer (Odocoileus virginianus) are highly valued wildlife assets that provide subsistence, economic and cultural benefits to hunters and rural communities. Yet, high density populations of these herbivores can contribute significantly to regeneration failures in a wide range of forest types. Pre-European settlement white-tailed deer densities were estimated to have been approximately 2{\textendash}4 deer km-2, and similar densities have been recommended to balance contemporary forest regeneration and wildlife objectives.\  We studied northern red oak (Quercus rubra L.) regeneration on neighboring tribal and state forests where socio-cultural differences have led to distinct hunting management practices and subsequent differences in wildlife-plant interactions. Tribes such as the Lac du Flambeau Chippewa have kept deer populations relatively low on reservation lands through active hunting practices. We used an observational study approach to compare in situ ungulate herbivory under low (2{\textendash}3 deer km-2) and high (\>10 deer km-2) population densities. We measured northern red oak regeneration on tribal and state forests in two management unit types: contiguous stands of oak \>15 ha in area and small residual {\textquotedblleft}pockets{\textquotedblright} of oak \<3 ha left by foresters as a source of seed and wildlife mast. Herbivory levels were significantly higher on state forests than tribal forests and were closely correlated with the density of larger seedlings, particularly in oak pockets. If herbivory levels are too high, even with adequate light, our results suggest that seedlings may not survive in densities sufficient to maintain northern red oak as a co-dominant species in mixed forests. However, when deer densities are kept at 2{\textendash}4 deer km-2, our results suggest that northern red oak seedlings can survive beyond browseable heights in sufficient numbers for maintaining oak. Tribal lands can provide contemporary examples of longstanding low to intermediate deer densities and sustainable deer{\textendash}forest relationships.

}, issn = {03781127}, doi = {10.1016/j.foreco.2010.05.030}, url = {/files/bibliography/10-053.pdf}, author = {Reo, Nicholas J. and Jason W. Karl} } @conference {50073, title = {Threshold models in restoration - can we ever predict threshold responses?}, booktitle = {19th Conference of Society for Ecological Restoration International}, year = {2009}, month = {08/2009}, address = {Perth, Western Australia, Australia}, abstract = {

Land managers and scientists often ask: \“How do I identify the threshold?\” or \“Where is the threshold?\” Such questions presume a great deal about the nature of thresholds that are, as yet, not generally understood and not necessarily general at all. In this talk, I review how the threshold concept has been considered in land management and argue five points. 1) Attempting to predict threshold responses is likely to be a waste of time in many cases. 2) We have not yet produced an adequate number of case histories about the consequences, scales, rates, and mechanisms of threshold behavior within different kinds of ecosystems, so it is difficult to structure monitoring programs to detect threshold responses. 3) Managing for resilient conditions, with attention to slow social and ecological variables, to minimize the risk of crossing a threshold is potentially useful but is controversial for managers. 4) We have a dim understanding of how inherent (i.e., not management-related) variations in landscapes influence threshold responses, but such understanding can be used to guide planning. 5) Recognizing the consequences of post-threshold states for restoration actions is the most straightforward use of the threshold concept at present. Examples are drawn from restoration approaches in the southwestern United States and elsewhere to support these assertions.

}, keywords = {restoration, threshold}, author = {Brandon T Bestelmeyer} } @conference {50072, title = {Threshold models linked to land classification and indicators as guides to restoration - propsects and pitfalls}, booktitle = {10th International Congress of Ecology: Ecology in a Changing Climate}, year = {2009}, month = {08/2009}, address = {Brisbane, Queensland, Australia}, abstract = {Threshold (or regime shift) models are useful for restoration because they match actions to conditions where benefits are likely to be maximized. The procedures by which threshold models should be applied, however, are in the early stages of development. Here, we describe ecological concepts and derivative elements of an approach to applying threshold models including 1) combining experiments, simulations, and local ecological knowledge to develop conceptual state-and-transition models representing specific geographic areas; 2) linking the models to soil, plant, and landscape process-based indicators detected in ground-based or remotely-sensed assessment; 3) recognizing model contingency with respect to varying land-use, soils and geomorphology, and climate; and 4) cooperative planning of restoration actions integrated with model-based experimentation and monitoring. We describe several tools that have been used for each element and limitations of the tools and concepts revealed in applications in the United States and Mongolia. We suggest that the integration of threshold/resilience concepts with scale-specific models, process-based indicators, spatial data on the biophysical and social environment, and restoration experiments is becoming an increasingly common solution to connecting abstract ideas with real-world restoration applications.}, keywords = {restoration, state-and-transition, STM, threshold}, author = {Brandon T Bestelmeyer and Jeffrey E. Herrick and D.D. Briske and Maria Fern{\'a}ndez-Gim{\'e}nez and Wu, X.B. and Joel R. Brown and Kris Havstad} } @article {50113, title = {Texture and scale in object-based analysis of subdecimeter resolution unmanned aerial vehicle (UAV) imagery}, journal = {IEEE Transactions on Geoscience and Remote Sensing}, volume = {47}, number = {3}, year = {2009}, month = {03/2009}, pages = {761-770}, chapter = {761}, abstract = {

Imagery acquired with unmanned aerial vehicles (UAVs) has great potential for incorporation into natural resource monitoring protocols due to their ability to be deployed quickly and repeatedly and to fly at low altitudes. While the imagery may have high spatial resolution, the spectral resolution is low when lightweight, off-the-shelf digital cameras are used, and the inclusion of texture measures can potentially increase the classification accuracy. Texture measures have been used widely in pixel-based image analysis, but their use in an object-based environment has not been well documented. Our objectives were to determine the most suitable texture measures and the optimal image analysis scale for differentiating rangeland vegetation using UAV imagery segmented at multiple scales. A decision tree was used to determine the optimal texture features for each segmentation scale. The error rate of the decision tree was lower, prediction success was higher, class separability was greater, and overall accuracy was higher (high 90\% range) at coarser segmentation scales, between 55 and 70 (range 10-80). The inclusion of texture measures increased classification accuracies at nearly all segmentation scales, and entropy was the texture measure with the highest score in most decision trees. The results demonstrate that UAVs are viable platforms for rangeland monitoring and that the drawbacks of low-cost off-the-shelf digital cameras can be overcome by including texture measures and using object-based image analysis highly suitable for very high resolution imagery.

}, keywords = {journal, monitoring, remote sensing, texture, UAV}, doi = {10.1109/TGRS.2008.2009355}, url = {/files/bibliography/09-010.pdf}, author = {Andrea S. Laliberte and A. Rango} } @conference {50164, title = {Teachers in the desert: Creating ecological reserech opportunities for teachres and students on the US Mexico border}, booktitle = {93rd Ecological Society of America Annual Meeting}, year = {2008}, month = {August 3-8, 2008}, pages = {OOS 17-8}, address = {Milwaukee, WI}, abstract = {Considerable research provides evidence for the value of teaching science using enhanced context strategies. These strategies include making learning relevant to students by using real-world examples and problems as well as taking students out of the classroom to learn about the topic. Unfortunately, these best practices are seldom used in the border region of southern New Mexico and west Texas due to a lack of funding, few teachers trained in inquiry-based science practices, and a lack of locally relevant curriculum. Ecological science here is often taught only from a textbook, a method that fails to demonstrate the excitement inherent in inquiry-based ecological science research. As part of the Teaching Ecological Complexity project funded by NSF, the Asombro Institute for Science Education and the Jornada Basin Long-Term Ecological Research Program conducted a two-week teacher professional development workshop in July 2008. High school teachers were immersed in their own ecological research projects, and they presented their hypotheses and results with the use of qualitative conceptual models. They also had opportunities to share and compare data collected by teachers and students at five other LTER sites. All workshop activities and research projects were correlated with state science and math education standards, making them instantly relevant and useful for teachers in the upcoming school year.}, keywords = {Asombro, student, teacher}, author = {Brandon T Bestelmeyer and R. Somerday} } @conference {50289, title = {Technology and research needs to support soil change studies in reserach and soil survey}, booktitle = {Geological Society of America}, series = {2008 Joint Meetings}, year = {2008}, month = {October 5-9, 200}, pages = {679-11}, address = {Houston, TX}, abstract = {Soil survey products must evolve to address the effects of management practices on the soil resource. There is a rising demand by soil survey customers interested in sustainable use of natural resources for information about land-use impacts on soil quality, ecological processes, and soil function. Meeting this demand requires new soil survey approaches to characterize soil change in agricultural and non-agricultural ecosystems. The challenge is to identify cost-effective measurement tools and data comparison techniques that are sensitive enough to reflect functional changes in soil properties. Methods are needed to measure or model key dynamic soil properties (DSP{\textquoteright}s) and link them with conceptual state-based models to forecast biotic-abiotic interactions and resilience. Concepts and terms that apply to soil change, including state variables, fluctuation changes, trend, rates and pathways of change, thresholds, reversibility, and characteristic response time, will be reviewed and needs for improvements through research, testing, and academic debate will be identified. The following research needs will be presented: 1) capturing the spatial and temporal variability of DSP{\textquoteright}s, 2) quantification of thresholds and relationships between DSP{\textquoteright}s and functions, and 3) interpretive tools or metrics to compare non-impacted soil pedons with those impacted by erosion, tillage, or other disturbances. The benefits of integrating soil survey DSP data with information about rates, pathways, and thresholds of change derived from long-term studies are also identified. To stay relevant to society{\textquoteright}s needs soil survey must document state variables (DSP{\textquoteright}s) for a wide range of land uses and management systems.}, keywords = {natural resources, soil survey, sustainable}, author = {A.J. Tugel and S.A. Wills and A. O{\textquoteright}Green} } @article {50291, title = {Targeted grazing of one seed juniper sapling with small ruminants: Influence of stocking density and mixed grazing in summer and spring}, year = {2008}, month = {June 15, 2008}, pages = {49}, abstract = {A study was conducted to examine the potential for targeted grazing of one seed juniper saplings with small ruminants. A 2x2 factorial design was used consisting of targeted grazing application with sheep and goats at two stocking densities in spring and summer. Ten female goats or five goats plus four ewes were placed on 10x10 m plots for 1 day (high density treatment) or 20x30 m plots for 6 days (low density treatment) with 2 replicates per treatment per season. Stocking rate for both treatments was 1.1 AU/ha/yr. Time spent feeding on juniper and utilization of herbaceous vegetation did not differ between seasons. Goats spent more time feeding on juniper in the high density stocking treatment vs low density, although differences were greater in mixed species plots (34.4 vs 17.7\%) than in plots with only goats (28.2 vs 22.2\%). Utilization of herbaceous vegetation was greater in low vs high density stocking (67.0 vs 59.6; P = 0.05), and for mixed vs single species grazing (69.8 vs56.9); P < 0.01). Targeted grazing at high stocking density with sheep and goats may be a tool for increasing juniper use by goats. Low density grazing appears to encourage selective grazing and more intense utilization of the understory.}, keywords = {annual report, one seed juniper, ruminants, saplings, western regiona}, author = {S. A. Utsumi and Andr{\'e}s F. Cibils and Richard E. Estell and J.W. Walker} } @proceedings {50295, title = {Targeted grazing with small ruminants to control encroachment of one-seed juniper saplings}, year = {2008}, month = {July 18, 2008}, pages = {19-20}, address = {Corona, NM}, abstract = {Shrub encroachment into rangelands is a concern for livestock producers. A study was conducted to determine whether targeted grazing with small ruminants could be used to suppress one-seed juniper sapling growth. Since most domestic ruminants avoid feeding on juniper, this study focused on approaches to boost shrub browsing intensity to levels that would kill or cripple sapling growth without permanently damaging the grass understory. We tested use of goats or mixed species (goats plus sheep) during two periods of growth (summer and spring) at two stocking densities (10 and 60 m2/AU/day) with two replicates per treatment. Animals tended to strip needles and thin stems from young saplings, whereas impacts on older saplings consisted mainly of bark stripping. Mixed species high-density stocking resulted in the fewest tall saplings (> 1 m) in the low utilization category (< 33\% of branches defoliated), the most small (<0.5 m) saplings with heavy use (> 66\% of branches defoliated), and the fewest saplings with low (< 33\%) bark stripping during spring. Fecal analysis indicated juniper intake accounted for about 25\% of animal diets across treatments. A great deal of animal to animal variation was observed, with juniper intake accounting for up to 60\% of some individual animal diets. Season did not affect time spent feeding on juniper or understory utilization. Rate of sapling kill and vegetation characteristics are currently being monitored. Results suggest mixed grazing at high stocking density can boost utilization of juniper saplings by goats.}, keywords = {Corona, juniper, proceedings, ruminants, saplings}, url = {/files/bibliography/08-037.pdf}, author = {S. A. Utsumi and Andr{\'e}s F. Cibils and Richard E. Estell and J.W. Walker and S.H. Cox} } @article {50298, title = {A transport-distance approach to scaling erosion rates: 1. Background and model development}, journal = {Earth Surface Processes and Landforms}, volume = {33}, number = {5}, year = {2008}, note = {//NMSU,USDA//LTER V//entered 05/29/2008}, month = {2008}, pages = {813-826}, abstract = {

The process basis of existing soil-erosion models is shown to be ill-founded. The existing literature builds directly or indirectly on Bennett{\textquoteright}s (1974) paper, which provided a blueprint for integrated catchment-scale erosion modelling. Whereas Bennett recognized the inherent assumptions of the approach suggested, subsequent readings of the paper have led to a less critical approach. Most notably, the assumption that sediment movement could be approximated by a continuity equation that related to transport in suspension has produced a series of submodels that assume that all movement occurs in suspension. For commonly occurring conditions on hillslopes, this case is demonstrably untrue both on theoretical grounds and from empirical observations. Elsewhere in the catchment system, it is only partially true, and the extent to which the assumption is reasonable varies both spatially and temporally. A second ground-breaking paper {\textendash} that of Foster and Meyer (1972) {\textendash} was responsible for subsequent uncritical application of a first-order approximation to deposition based on steady-state analysis and again a weak empirical basis. We describe in this paper an alternative model (MAHLERAN {\textendash} Model for Assessing Hillslope-Landscape Erosion, Runoff And Nutrients) based upon particle-travel distance that overcomes existing limitations by incorporating parameterizations of the different detachment and transport mechanisms that occur in water erosion in hillslopes and small catchments. In the second paper in the series, we consider the sensitivity and general behaviour of MAHLERAN, and test it in relation to data from a large rainfall-simulation experiment. The third paper of the sequence evaluates the model using data from plots of different sizes in monitored rainfall events. From this evaluation, we consider the scaling characteristics of the current form of MAHLERAN and suggest that integrated modelling, laboratory and field approaches are required in order to advance the state of the art in soil-erosion modelling. Copyright {\textcopyright} 2008 John Wiley \& Sons, Ltd.

}, keywords = {article, erosion, hydrology, hydrology, erosion, hydrology, sediment transport, hydrology, soil-erosion model, journal, model, MAHLERAN, model, soil-erosion}, doi = {10.1002/esp.1624}, url = {files/bibliography/JRN00489.pdf}, author = {John Wainwright and A.J. Parsons and Eva N. M{\"u}ller and Richard E. Brazier and Mark D. Powell and Fenti, Bantigegne} } @article {50297, title = {A transport-distance approach to scaling erosion rates: 2. Sensitivity and evaluation of MAHLERAN}, journal = {Earth Surface Processes and Landforms}, volume = {33}, number = {6}, year = {2008}, note = {//NMSU,USDA//LTER V//entered 05/29/2008}, month = {2008}, pages = {962-984}, abstract = {

In the first paper in this series, we demonstrated that most process-based erosion models have a series of in-built assumptions that led us to question their true process basis. An alternative soil-erosion model (MAHLERAN {\textendash} Model for Assessing Hillslope-Landscape Erosion, Runoff And Nutrients) based upon particle-travel distance has been presented in the first paper in this series and this paper presents the first of two evaluations of the model. Here, a sensitivity analysis shows that the numerical model is consistent with the analytical model of Parsons et al. (2004) and demonstrates that downslope patterns of sediment flux on hillslopes are a complex interaction of rainfall intensity, duration and pattern; hillslope gradient; surface roughness and sediment size. This result indicates that the spatial scaling of sediment transfers on hillslopes is a non-trivial problem and will vary from point to point and from event to event and thus from year to year. The model is evaluated against field data from a rainfall-simulation experiment on an 18 m {\texttimes} 35 m plot for which there are sub-plot-scale data on runoff hydraulics and sediment flux. The results show that the model is capable of reproducing the sedigraph with an overall normalized root-mean-square error of 18{\textperiodcentered}4\% and Nash{\textendash}Sutcliffe efficiency of 0{\textperiodcentered}90. Spatial and temporal patterns of particle-size distributions of the eroded sediment are also reproduced very well, once erosion parameters have been optimized for the specific soil conditions. Copyright {\textcopyright} 2008 John Wiley \& Sons, Ltd.

}, keywords = {article, erosion, hydrology, hydrology, erosion, hydrology, sediment transport, hydrology, soil-erosion model, hydrology, validation model, journal, model, MAHLERAN, model, soil-erosion, model, validation}, doi = {10.1002/esp.1623}, url = {files/bibliography/JRN00490.pdf}, author = {John Wainwright and A.J. Parsons and Eva N. M{\"u}ller and Richard E. Brazier and Mark D. Powell and Fenti, Bantigegne} } @article {50299, title = {A transport-distance approach to scaling erosion rates: 3. Evaluating scaling characteristics of MAHLERAN}, journal = {Earth Surface Processes and Landforms}, volume = {33}, year = {2008}, note = {//NMSU,USDA//LTER V//entered 05/29/2008, In Press available online; updated 06/12/2008, in print; PDF on file}, month = {2008}, pages = {1113-1128}, abstract = {

In the two previous papers of this series, we demonstrated how a novel approach to erosion modelling (MAHLERAN {\textendash} Model for Assessing Hillslope-Landscape Erosion, Runoff And Nutrients) provided distinct advantages in terms of process representation and explicit scaling characteristics when compared with existing models. A first evaluation furthermore demonstrated the ability of the model to reproduce spatial and temporal patterns of erosion and their particle-size characteristics on a large rainfall-simulation plot. In this paper, we carry out a more detailed evaluation of the model using monitored erosion events on plots of different size. The evaluation uses four plots of 21{\textperiodcentered}01, 115{\textperiodcentered}94, 56{\textperiodcentered}84 and 302{\textperiodcentered}19 m2, with lengths of 4{\textperiodcentered}12, 14{\textperiodcentered}48, 18{\textperiodcentered}95 and 27{\textperiodcentered}78 m, respectively, on similar soils to the rainfall-simulation plot, for which runoff and erosion were monitored under natural rainfall. Although the model produces the correct ranking of the magnitude of erosion events, it performs less well in reproducing the absolute values and particle-size distributions of the eroded sediment. The implications of these results are evaluated in terms of requirements for process understanding and data for parameterization of improved soil-erosion models. We suggest that there are major weaknesses in the current understanding and data underpinning existing models. Consequently, a more holistic re-evaluation is required that produces functional relationships for different processes that are mutually consistent, and that have appropriate parameterization data to support their use in a wide range of environmental conditions. Copyright {\textcopyright} 2008 John Wiley \& Sons, Ltd.

}, keywords = {article, erosion, hydrology, hydrology, erosion, hydrology, scaling, hydrology, sediment transport, hydrology, soil-erosion model, hydrology, validation model, journal, model, MAHLERAN, model, scaling, model, soil-erosion, model, validation}, doi = {10.1002/esp.1622}, url = {files/bibliography/JRN00491.pdf}, author = {John Wainwright and A.J. Parsons and Eva N. M{\"u}ller and Richard E. Brazier and Mark D. Powell and Fenti, Bantigegne} } @conference {50312, title = {Tipping points in rangelands: The scales of social-biophysical interactions}, booktitle = {Ecological Society of America Abstracts}, year = {2007}, note = {Duplicate of 215186. Use 215042 for reporting purposes}, month = {August 5-10, 200}, pages = {SYMP 2-7}, address = {San Jose, CA}, abstract = {Ecological and socio-economic processes are driving many of the world{\textquoteright}s rangelands beyond {\textquotedblleft}tipping points{\textquotedblright} to degraded states, but we have a poor understanding of the mechanisms by which these processes are linked to each other. We argue that this is due largely to the lack of data on region-scale patterns. We review three key concepts guiding our approach to investigating rangeland degradation at regional scales. First, a mechanistic understanding of tipping points must be based on understanding cross-scale relationships in pattern-process interactions. One insight is that the scales at which we should look for significant patterns/processes (e.g., those that explain variation in vegetation and soil degradation) vary with context and are often broader than we implicitly recognize. Second, transitions to degraded states are strongly conditioned by climo-edaphic heterogeneity. We are only beginning to identify and quantify the key attributes that govern transitions and know little about how climate change will modify those relationships. Finally, it is widely held that human behaviors underlie the approach to tipping points and loss of resilience, but we have little systematic understanding of how variations in behavior affect them. In the U.S., for example, spatial patterns of control of public grazing lands established under the Taylor Grazing Act, the adoption of more stringent rangeland oversight policies (e.g., the National Environmental Policy Act), and changing motivations of landowners may have large and unrecognized impacts on transitions. Improvements to the tools and policies we use to react to tipping points in rangelands will require broad-scale, social-ecological approaches that are still nascent.}, keywords = {socio-economic, tipping points}, author = {Brandon T Bestelmeyer and R. K. Skaggs and Debra C. Peters and Kris Havstad} } @conference {50398, title = {Trends, ecological covariates,and some conservation implications of rodent abundance in a montane island of southern New Mexico}, booktitle = {14th Annual Conference of the Wildlife Society}, year = {2007}, month = {September 22-26,}, pages = {p. 97}, address = {Tucson, AZ}, abstract = {Rodents provide food for a number of species that are targeted for management in southwestern forests. The Mexican spotted owl (Strix occidentalis lucida) and northern goshawk (Accipiter gentiles) are two examples of predators that shape management of several thousands of montane acres in this region. There are a number of ecological factors that effect rodent populations, which in turn, influence population numbers and distribution of focal predators. Some factors like habitat condition can be readily manipulated, while other factors like precipitation cannot. Population dynamics of five rodent species commonly consumed by Mexican spotted owls in the Sacramento Mountains are influenced by interactions among habitat, weather, and fauna. Over a six-year period (1991-1996), we found that population numbers of two species of deermice (Peromyscus maniculatus and P. boylii) and voles (Microtus mogollonensis and M. longicaudus) exhibited dynamic patterns of fluctuation, particularly relative to the less fluctuating numbers of the larger woodrat species Neotoma mexicana. Using envirograms and an information-theoretic approach to model selection, we found only slight similarity in ecological predictor variables for each species. We surmised that populations of the two vole species would be the most feasible to increase through habitat management, followed by populations of the Mexican woodrat, and lastly the two species of deermice. By providing values of rodent abundance expected for specific values of key habitat variables and other prominent covariates that influence habitat-abundance relationships, our results can be used to assess and design management experiments intended to enhance food resources for at least one focal predator in upper montane forests of the Southwest.}, keywords = {ecological covariates, rodent abundance, trends}, author = {J.P. Ward and Block, W.M. and Van Horne, B.} } @proceedings {50414, title = {A three-tiered approach for coupled vegetation and soil sampling to develop ecological descriptions}, year = {2006}, month = {June 19-23, 2006}, abstract = {Ecological site descriptions (ESDs), alongside similar land classification systems, are used to describe the breadth of plant community types, community changes, and soil surface conditions that can occur within a particular land area. Vegetation dynamic processes and management may change the identity of plant communities over time, but there are a limited number of recognizable plant communities or vegetation states that are observed to occupy a given spatial position. Soil and climate variables are the key environmental attributes predicting the plant communities that can potentially occupy site. Consequently, soil survey products are tremendously useful for developing ESDs. Specifically, ecologically-similar soil map unit components are grouped to form ecological site classes. Soil maps can thus be used to anticipate the ecological sites and possible vegetation states present in a landscape. Ecological site descriptions have been developed by the NRCS alongside soil survey efforts and in soil survey updates. These efforts have resulted in the first generation of ESDs (formerly called range site descriptions). In spite of the great utility of these products, there are now a broader range of uses and users and increased scrutiny. Users have called for improvements in the clarity of classification criteria, increasing use and documentation of empirical data in developing classifications, and refinements to classifications in order accommodate state-and-transition models of vegetation dynamics. The latter issue is particularly important, as there is increasing evidence that the expression of vegetation dynamics and ecological thresholds may be governed by surprisingly subtle differences in soil properties that may or may not be distinguished in existing ESDs (e.g., Fuhlendorf and Smeins 1998, Bestelmeyer et al., 2006). Unfortunately, there are often few data available that can be used to investigate vegetation-soil relationships as a quantitative basis for producing or refining ESDs. The dearth of suitable data has many causes including 1) the lack of any vegetation data gathering associated with soil descriptions, 2) vegetation data that cannot be associated with soil pedon data, 3) too few samples of linked vegetation and soils to represent regional variation or to observe different vegetation states on the same soil types, 4)lack of geolocation and an inability to linked data to spatial layers such as modeled climate (e.g., Daly et al., 2002), 5) vegetation attributes are not sufficient to distinguish vegetation states or other important conditions, and 6) there are no data on surface soil attributes, and thus weak linkages to state-and-transition models and rangeland health. These limitations have precluded evaluation and refinement of ESDs by the science and management communities. In this presentation, we offer a comprehensive framework to overcome data limitations in the development of ESDs and other soil-vegetation-based land classification systems. The framework has four general components 1) training and employment vegetation/rangeland specialists who understand soils in soil survey and other efforts, 2) a set of vegetation sampling protocols that matches the pace of sampling in the field, 3) setting the goal of collecting data at many points with varying levels of precision rather than collecting data at a few points with unnecessarily high precision, and 4) systematic collection of data at georeferenced points and their storage in a database that links soil and vegetation properties. We provide details about these components and an example of how data can be used to generate inferences in an ESD context.}, keywords = {ecological descriptions, vegetation}, author = {Brandon T Bestelmeyer and A.J. Tugel and G. Peacock and H. Sanchez} } @article {50415, title = {Threshold Concepts and Their use in Rangeland Management and Restoration: The Good, The Bad and the Insidious}, journal = {Restoration Ecology}, volume = {14}, number = {3}, year = {2006}, month = {September 1, 200}, pages = {325-329}, chapter = {325}, abstract = {Ecological thresholds describe abrupt changes in ecological properties in time or space. In rangeland management, thresholds reflect changes in vegetation and soils that are expensive or impossible to reverse. The threshold concept has catalyzed important advances in rangeland management thinking, but it has also introduced two classes of drawbacks. First, the ambiguity of the term "threshold" and the desire for simplicity in its application has led to an over-emphasis on classification thresholds, such as vegetation cover values. Uncritical use of classification thresholds may lead to the abandonment of management efforts in land areas that would otherwise benefit from intervention. Second, it is possible that the invocation of thresholds and irreversible degradation may eventually result in the wholesale conversion of land areas that would have been recoverable or served important societal functions, such as biodiversity maintenance, that are not reflected in threshold definitions. I conclude with a recommendation to clarify the nature of thresholds by defining the relationships among pattern, process, and degradation and distinguishing preventive thresholds from restoration thresholds. We must also broaden the attributes used to define states and thresholds.}, keywords = {biodiversity, ecological thresholds, exurban development, grazing, landscape ecology, rangeland health, state-and-transition models, thresholds}, url = {/files/bibliography/06-030.pdf}, author = {Brandon T Bestelmeyer} } @article {50657, title = {A {\textquoteleft}{\textquoteleft}test of concept{\textquoteright}{\textquoteright} comparison of aerodynamic and mechanical resuspension mechanisms for particles deposited on field rye grass (Secale cercele). Part 1. Relative particle flux rates}, journal = {Atmospheric Environment}, volume = {38}, year = {2004}, note = {//NONE//NONE// Listed in LTER IV 2004 annual report//Added 08/10/2004, Updated 05/16/2006}, month = {2004}, pages = {4789-4797}, abstract = {Resuspension of uniform latex micro spheres deposited on a single seed pod of field rye grass stalk and head was investigated experimentally in a wind tunnel. The experiment was designed to distinguish aerodynamic (viscous and turbulent) mechanisms from mechanical resuspension resulting from the oscillatory impact of the grass hitting a stationary object. The experiment was run for deposited spherical latex particles with diameters from 2 to 10 mm. Wind tunnel tests were run for wind speeds from 2 to 18.5ms1 and a turbulence intensity (root-mean-square fluctuation wind speed/mean wind speed) of 0.1. Our experiments showed the following for our test of concept experiment:* Resuspension particle flux increases when mechanical impacts occur.* Mechanical resuspension dominated for 2 mm particles over purely aerodynamic resuspension, but for larger particles aerodynamic mechanisms were roughly equally effective in resuspending particles.}, keywords = {aeolian processes, transport, aerodynamic, aerosol, article, grass, journal, resuspension, wind tunnel}, author = {D. E. Gillette and Robert E. Lawson Jr. and Roger S. Thompson} } @article {50658, title = {A {\textquoteleft}{\textquoteleft}test of concept{\textquoteright}{\textquoteright} comparison of aerodynamic and mechanical resuspension mechanisms for particles deposited on field rye grass (Secale cercele). Part 2. Threshold mechanical energies for resuspension particle fluxes}, journal = {Atmospheric Environment}, volume = {38}, year = {2004}, note = {//NONE//NONE// Listed in LTER IV 2004 annual report//Added 08/10/2004, Updated 05/16/2006}, month = {2004}, pages = {4799-4803}, abstract = {Kinetic energy from the oscillatory impacts of the grass stalk against a stationary object was measured with a kinetic energy measuring device. These energy inputs were measured as part of a resuspension experiment of uniform latex microspheres deposited on a single rye grass seed pod in a wind tunnel. The experiment was designed to measure resuspension from aerodynamic (viscous and turbulent) mechanisms compared to that from mechanisms from mechanical resuspension resulting from the oscillatory impact of the grass hitting a stationary object. The experiment was run for deposited spherical latex particles with diameters from 2 to 8.1 {\`\i}m. Wind tunnel tests were run for wind speeds from 2 to 18.5ms-1 and a turbulence intensity (root-mean-square fluctuation wind speed/mean wind speed) of 0.1.Our experiments showed the following:* Threshold mechanical energy input rates increased from 0.04 to 0.2 mJs-1 for resuspension of spherical polystyrenelatex particles from 2 to 8.1 {\`\i}m diameter.* Kinetic energy flux generated by mechanical impact of the wind-driven oscillating grass was found to be highlysensitive to slightly different placements and grass morphology.* The kinetic energy input by impaction of the grass against a stationary cylinder is roughly proportional to the kineticenergy flux of the wind.}, keywords = {aeolian processes, transport, aerodynamic, aerosol, article, grass, journal, resuspension, wind tunnel}, author = {D. E. Gillette and Robert E. Lawson Jr. and Roger S. Thompson} } @conference {50684, title = {Through the eyes of Lewis and Clark: wildlife abundance and distribution 200 years ago}, booktitle = {68th Annual Meeting of the Soil Science Society of America}, year = {2004}, month = {October 1, 2004}, pages = {121}, abstract = {The Lewis and Clark journals contain some of the earliest and detailed written descriptions of a large part of the United States before Euro-American settlement. We used the journal entries to map Lewis and Clark{\textquoteright}s encounters with wildlife and the human population and performed a GIS analysis to determine human influences on wildlife. Human influence was calculated by distance to the nearest settlement and settlement density in a 50-km radius. More species were present in areas with few human settlements, such as the west-central portion of the Plains. The fewest number of species were seen in areas with denser human population, along the Columbia River and west to the Pacific coast. Each species became more abundant with increasing distance from human settlements and with decreasing settlement densities. Bison, elk, grizzly, and wolves were predominantly found in the plains because the predators followed the then abundant prey population. Elk, bison, bighorn sheep, and wolves were absent from the Columbia Basin. The results show that humans had considerable influence over wildlife distribution and abundance, even under relatively low human population densities. This study offers an improved understanding of the historical reference condition and shows that human influences should not be underestimated when investigating historical ecological conditions.}, keywords = {200 years ago, abundance, distribition, Lewis and Clark, wildlife}, author = {Andrea S. Laliberte and Ripple, W.J.} } @conference {50709, title = {Transitions in rangeland evaluations}, booktitle = {57th Annual Meeting, Society for Range Management}, year = {2004}, month = {January 25, 2004}, pages = {296}, address = {Salt Lake City, UT}, abstract = {Historically, rangeland evaluations have been concerned with the inventory and monitoring of upland physical and biological characteristics. Vascular plant composition was a critical measure for determining rangeland condition and trend. Managers used key areas and key forage species to determine if livestock and wildlife adequately used the available land area and its forage. Over the years, the principle reasons for evaluating rangelands have remained the same. They are to determine the current status and trend of the natural resources on rangelands. However, we began to recognize that the traditional rangeland condition classification system and the successional model on which it was based had severe limitations when applied to many semiarid and arid rangelands. We reevaluated our views of succession and the relationship between those views and the status of rangelands. We broadened our areas of concern from only uplands to including wetlands and riparian areas. In addition, we looked beyond the impacts of only our primary use of an individually fenced unit, which was often livestock grazing, to multiple uses and units within a watershed or multiple watersheds within a basin. New assessment techniques are attempting to link abiotic with biotic factors and to integrate them into evaluations of ecosystem status on rangelands. Remote sensing tools now provide a means to evaluate larger areas. Future evaluations will examine the sustainability of rangelands, but they will need to develop acceptable measures of not just biological and physical factors, but also social and economicfactors relating to rangelands.}, author = {D.A. Pyke and Jeffrey E. Herrick} } @article {50708, title = {Transitions in rangeland evaluations: a review of the major transitions in rangeland evaluations during the last 25 years and speculation about future evaluations}, journal = {Rangelands}, volume = {25}, number = {6}, year = {2004}, month = {January 1, 2004}, pages = {22-30}, abstract = {Historically, rangeland evaluations have been concerned with the inventory and monitoring of upland physical and biological characteristics. Vascular plant composition was a critical measure for determining rangeland condition and trend. Managers used key areas and key forage species to determine if livestock and wildlife appropriately used the available land area and its forage. Over the years, the principle reasons for evaluating rangelands have remained the same. They are to determine the current status and trend of the natural resources on rangelands. However, we began to recognize that the traditional rangeland condition classification system and the successional model on which it was based had severe limitations when applied to many semiarid and arid rangelands. We reevaluated our views of succession and the relationship between those views and the status of rangelands. We broadened our areas of concern from uplands only to include wetlands and riparian areas. In addition, we looked beyond the impacts of only our primary use of an individually fenced unit, which was often livestock grazing, to multiple uses and units within a watershed or multiple watersheds within a basin. New assessment techniques are attempting to link abiotic with biotic factors and to integrate them into evaluations of ecosystem status on rangelands. Remote sensing tools now provide a means to evaluate larger areas. Future evaluations will examine the sustainability of rangelands, but they will need to develop acceptable measures of not just biological and physical factors, but also social and economic factors relating to rangelands.}, keywords = {evaluations, rangeland, transitions}, author = {D.A. Pyke and Jeffrey E. Herrick} } @conference {50717, title = {Temporal variation in water availability}, booktitle = {Sixth Symposium on the Natural Resources of the Chihuahuan Desert Region}, year = {2004}, month = {October 15, 2004}, pages = {42}, address = {Alpine, TX}, abstract = {Desert regions in the southwestern United States and northern Mexico exhibit a high degree of temporal variability in water availability. This temporal variability is a result of shifting climate regimes over centuries and decades, interannual variation in weather patterns, seasonal differences n the nature of winter and summer precipitation, within-season variability of precipitation frequency and magnitude, soil textural properties, differences in vegetation structure, and soil water. Pulses of rainfall during the summer growing season are highly unpredictable and punctuated by intervening dry periods of variable lengths. These dry periods are frequently severe enough to limit biotic activity and modify abiotic processes. Therefore, within a landscape type the relationship between aboveground net primary productivity and annual rainfall lacks predictive power due to the pulse-driven nature of these systems. In the Chihuahuan Desert encroachment of C3 shrub species into areas formerly dominated by C4 grasses appears to interact with water variability and create positive feedbacks that facilitate further shrub encroachment and loss of grass cover. In order to understand these systems, we need to develop knowledge of how temporal patterns in water availability affect ecosystem water use, nutrient availability, productivity, and species composition. Data from rainfall manipulation experiments, Bowen-Ration towers, and long-term soil moisture illustrate that mesquite shrubs respond to both small and large rainfall events, respiratory losses of carbon dioxide often offset photosynthetic uptake of carbon dioxide, and the capacity for carbon sequestration during summer months is largely driven by rainfall patterns.}, keywords = {Chihuahuan Desert, pulse-driven nature, shifting climate regimes, temporal variation, water availability, weather patterns}, author = {K. A. Snyder and S. Tartowski and V. P. Gutschick} } @article {50805, title = {Transitions in rangeland evaluations: A review of the major transitions in rangeland evaluations during the last 25 years and speculation about future evaluations}, journal = {Rangelands}, volume = {25}, number = {6}, year = {2003}, note = {Trade Journal}, month = {2003}, pages = {22-30}, abstract = {

New technologies in remote sensing allow us to view land changes over much larger areas than in the past. Our increased understanding of the importance of linkages among the living components (all of the interacting organisms) and non-living components (e.g., soils, air, and water) of rangelands and processes occurring within rangelands (e.g., nutrient and water cycling as well as energy flow) has led to the development of new approaches for evaluating rangelands. We even occasionally try to include social, economic, and legal aspects of rangelands in evaluations. This article is an opportunity to review the major transitions in rangeland evaluations during the last 25 years and realize how much change has occurred in our approaches. It also provides an opportunity to speculate about the future evaluations.

}, keywords = {future, rangelands, remote sensing, Trade journal, transition}, url = {/files/bibliography/04-030.pdf}, author = {D.A. Pyke and Jeffrey E. Herrick} } @conference {50848, title = {Top-down vs. bottom-up: Alternative, complementary scaling approaches}, booktitle = {87th Annual Meeting, Ecological Society of America}, year = {2002}, month = {August 4-9, 2002}, pages = {14}, address = {Tucson, AZ}, abstract = {Many ecologists measure ecosystem processes and characteristics over a small area and then extrapolate to a larger spatial extent (bottom-up scaling). Others use tools such as global circulation models to study processes over an extremely large region and then use those results at finer spatial scales (top-down scaling). Since most ecological management takes place at the landscape scale, it is essential to understand how both finer and coarser processes function at that level. We discuss applications of bottom-up and top-down scaling and illustrate general recommendations and specific pitfalls, emphasizing the similarities between the two approaches. Examples are given of the use and misuse of downscaling large-scale atmospheric data for use as input to vegetation and biogeochemical models. Top-down scaling is also used to apply data from global vegetation models to scales at which management decisions are made. Bottom-up scaling is required to aggregate land surface heterogeneities for use in describing fluxes into and out of the atmosphere and for extrapolating vegetation data from sampling plots to larger areas. Both scaling up and scaling down are needed to understand ecosystem functions at the landscape scale so that we can make accurate predictions and effective management decisions.}, author = {Coughenour, M. and R.A. Pielke and Sarah Goslee} } @article {50896, title = {Transport of phenolic compounds from leaf surface of creosotebush and tarbush to soil surface by precipitation}, journal = {Journal of Chemical Ecology}, volume = {28}, number = {12}, year = {2002}, month = {December 1, 2002}, pages = {2469-2476}, abstract = {During the last 100 years, many desert grasslands have been replaced by shrublands. One possible mechanism by which shrubs outcompete grasses is through the release of compounds that interfere with neighboring plants. Our objective was to examine the movement of secondary compounds from the leaf surface of creosotebush and tarbush to surrounding soil surfaces via precipitation. Units consisting of a funnel and bottle were used to collect stemflow, throughfall, and interspace precipitation samples from 20 creosotebush (two morphotypes) and 10 tarbush plants during three summer rainfall events in 1998. Precipitation samples were analyzed for total phenolics (both species) and nordihydroguaiaretic acid (creosotebush only). Phenolics were detected in throughfall and stemflow of both species with stemflow containing greater concentrations than throughfall (0.088 and 0.086 mg/ml for stemflow and 0.022 and 0.014 mg/ml for throughfall in creosotebush morphotypes "U" and "V," respectively; 0.044 and 0.006 mg/ml for tarbush stemflow and throughfall, respectively). Nordihydroguaiaretic acid was not found in any precipitation collections. Our results show that phenolic compounds produced by creosotebush and tarbush can be transported to the soil surface by precipitation, but whether concentrations are ecologically significant is uncertain. Secondly, nordihydroguaiaretic acid was not present in the runoff from creosotebush.}, url = {http://www.springerlink.com/content/t630375412426743/fulltext.pdf}, author = {P.W. Hyder and E.L. Fredrickson and Richard E. Estell and M.E. Lucero} } @article {50942, title = {Temperature and emissivity separation from multispectral thermal infrared observations}, journal = {Remote Sensing of Environment}, volume = {79}, number = {2-3}, year = {2002}, note = {ARIS entry by Beltsville December 4, 2000}, month = {February 1, 2002}, pages = {189-198}, abstract = {Knowledge of the surface emissivity is important for determining the radiation balance at the land surface. For heavily vegetated surfaces, there is little problem since the emissivity is relatively uniform and close to one. For arid lands with sparse vegetation, the problem is more difficult because the emissivity of the exposed soils and rocks is highly variable. With multispectral thermal infrared (TIR) observations, it is possible estimate the spectral emissivity variation for these surfaces. The data we will present is from the Thermal Infrared Multispectral Scanner (TIMS) instrument which has six channels in the 8 to 12 micron region. TIMS is a prototype of the TIR portion of the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) instrument on NASA{\textquoteright}s Terra (EOS- AM1) platform launched in December 1999. The Temperature Emissivity Separation algorithm, developed for use with ASTER data, is used to extract the temperature and six emissivities from the six channels of TIMS data. The algorithm makes use of the empirical relation between the range of observed emissivities and their minimum value. This approach was applied to the TIMS data acquired over the USDA/ARS Jornada Experimental Range in New Mexico. The Jornada site is typical of a desert grassland where the main vegetation components are grass (black grama) and shrubs (primarily mesquite) in the degraded grassland. The data presented here are from flights at a range of altitudes from 800m to 5000m yielding a pixel resolution from 3 to 12 meters. The resulting spectral emissivities are in qualitative agreement with laboratory measurements of the emissivity for the quartz rich soils of the site. The derived surface temperatures are in reasonable agreement with ground measurements.}, url = {/files/bibliography/02-100.pdf}, author = {T. J. Schmugge and A.N. French and Jerry Ritchie and A. Rango and Pelgrum, H.} } @article {51013, title = {Tree mortality in gap models: Application to climate change}, journal = {Climatic Change}, volume = {51}, year = {2001}, month = {December 1, 2001}, pages = {509-540}, abstract = {

Gap models have been used extensively to study successional dynamics for a wide variety of purposes and applications. Moreover, the gap model structure and design have been used in a host of other forest and grassland succession models; comparisons have also been made between forest and grassland structure and dynamics using gap models. Yet, considering the widespread use of gap models, it seems somewhat surprising that few modelers have critically evaluated the limitations of gap modeling and shortcomings of the algorithms that comprise the gap model. A model component that has received the least critical attention is the simulation of plant death (i.e., mortality), which is strikingly similar across nearly all gap models. In this paper, we review the treatment of mortality in gap models, evaluate the relationships used to control mortality in the current generation of gap models, and then assess the prospects for making improvements, especially for applications involving global climate change.

}, doi = {10.1023/A:1012539409854 }, url = {/files/bibliography/01-036.pdf}, author = {Keane, Robert I. and Austin, Mike and Field, Christopher and Huth, Andreas and Lexer, Manfred J. and Debra C. Peters and Solomon, Allen and Wyckoff, Peter} } @article {51092, title = {A test of a climatic index of dune mobility using measurements from the southwestern United States}, journal = {Earth Surface Processes and Landforms}, volume = {25}, year = {2000}, note = {//USDA//NONE//entered 08/25/2008}, month = {2000}, pages = {197}, abstract = {The climatic index of dune mobility developed by Lancaster (1988) has been applied to a variety of different environments. The index is, however, untested and unverified. We tested the index by comparison of values of the dune mobility index calculated from climate data with rates of sand transport measured at three stations in Arizona and New Mexico over the period 1985 to 1997. Our results show that changes in measured rates of sand transport closely parallel temporal changes in the dune mobility index. The mobility index is, however, a relatively poor predictor of the magnitude of actual sand transport on a year-to-year basis. This discrepancy is probably due to the fact that sand transport rates at these sites are strongly influenced by vegetation cover, the state of which may lag changes in annual precipitation. There is, however, a good relation between the mean annual mobility index and mean annual rates of sand transport. This indicates that the dune mobility index is a valid predictor of the long-term state of the aeolian system and can be used confidently for the purposes for which it was originally intended. Copyright {\textcopyright}2000 John Wiley \& Sons, Ltd.}, keywords = {aeolian, climatic gradient, aeolian, dune mobility index, aeolian, sand transport, article, climatic gradient, aeolian, desert winds, Geomet, journal}, author = {Lancaster, Nicholas and Paula Helm} } @article {51169, title = {Tolerance to nitrogenous explosives and metabolism of TNT by cell suspensions of datura innoxia}, journal = {In Vitro Plant}, volume = {35}, number = {6}, year = {1999}, month = {November 1, 1999}, pages = {480-486}, abstract = {

Cell suspension cultures of Datura innoxia were incubated in the presence of the nitro-substituted explosives 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazine (RDX), and 1,3,5,7-tetranitro-1,3,5,7-tetraazocyclooctane (HMX). Cellular tolerance levels and TNT biotransformation kinetics were examined. Tolerance to TNT varied as cell suspensions aged. Concentrations of RDX or HMX in excess of reported solubility limits produced no observable changes in cell viability. GC/MS analysis of TNT-treated cell media and cell lysates revealed rapid removal of TNT. Within 12 h, less than 1\% of the initial TNT remained in the growth medium. Aminodinitrotoluenes (ADNTs), known metabolites of TNT, accumulated transiently in cell lysates, and to a lesser extent in cell media. ADNT concentrations started to decrease after 3 h. After 12 h, less than 5\% of the initial TNT could be detected as ADNT. Total ADNTs never exceeded 26\% of initial TNT, suggesting that additional biotransformation steps also occurred. No other nitroaromatics were detected. A pseudo-first order rate constant for TNT clearance was calculated, k=0.40 h-1. D. innoxia cell suspension cultures demonstrated virtually complete clearance of TNT and of subsequent ADNT metabolites in less than 12 h. This rapid metabolism of nitroaromatics by the Datura cell suspension system indicates the utility of this system for further molecular and biochemical studies.

}, keywords = {bioremediation, biotransformation, nitroaromatics, phytoremediation}, doi = {10.1007/s11627-999-0072-3}, url = {/files/bibliography/694.pdf}, author = {M.E. Lucero and W. Mueller and Hubstenberger, J. and Phillips, G.C. and M. A. O{\textquoteright}Connell} } @article {51176, title = {Transmission losses in rills on dryland hillslopes}, journal = {Hydrological Processes}, volume = {13}, year = {1999}, note = {//NMSU//LTER III//}, month = {1999}, pages = {2897-2905}, abstract = {

Transmission losses through the beds of hillslope rills were studied at two sites in the semi-arid southwestern U.S. At one site the rills were sand-bedded and at the other they were gravel-bedded. Transmission losses in the sand-bedded rills are about 66\% higher than those in the gravel-bedded rills. The former show evidence of increasing transmission loss with increasing depth of flow, whereas the latter do not. In both cases, transmission losses in the rills are about an order of magnitude greater than infiltration losses in adjacent interrill areas. Copyright {\textcopyright} 1999 John Wiley \& Sons, Ltd.

}, keywords = {article, articles, hydrology, dryland hillslopes, hydrology, rills, hydrology, transmission loss, journal, journals}, doi = {10.1002/(SICI)1099-1085(19991215)13:17<2897::AID-HYP905>3.0.CO;2-B}, url = {files/bibliography/JRN00293.pdf}, author = {A.J. Parsons and John Wainwright and Stone, Peter M. and Athol D. Abrahams} } @article {51385, title = {Tarbush leaf surface terpene profile in relation to mammalian herbivory}, journal = {Journal of Chemical Ecology}, volume = {24}, year = {1998}, month = {January 1998}, pages = {1-12}, abstract = {

Tarbush (Flourensiacernua DC.) is a generally unpalatable shrub native to the Chihuahuan Desert and with a resinous leaf surface containing several terpenes. Tarbush epicuticular wax concentration has previously been linked to degree of use by livestock in our laboratory. In 1989 and 1990, cattle, sheep, and goats were densely stocked in tarbush-containing paddocks for 6 to 9 days. Degree of use of 20 permanently marked plants in each paddock (8 paddocks, 2 sites, only 10 plants were monitored in 4 of the paddocks the first year) was recorded daily both years. Thus, no destructive sampling of plants was possible. A high percentage of tarbush in diets and differential use of individual tarbush plants were observed in this companion study. In 1991, leaves were collected from these plants (n = 160) during the same stage of maturity. Leaf surface compounds were extracted with ethanol, and mono- and sesquiterpenes were analyzed using gas chromatography/ion trap mass spectrometry. Our objective was to examine whether degree of tarbush use during the high-density study was related to chemistry of the same plants the following year. Plants were separated into three categories after preliminary data evaluation (Category 1: \> 50\% use at period midpoint; Category 2: \< 50\% use at midpoint but \> 50\% use at period end; Category 3: \< 50\% use at period end). Multivariate analysis is being used to examine relationships of individual plant use with dry matter, ash, epicuticular wax, and several individual and subgroups of mono- and sesquiterpenes (oxygenated and hydrocarbon monoterpenes and sesquiterpenes). Preliminary evaluation suggests chemical subgroup variables in 1991 were related to degree of herbivory in 1989 and 1990, although statistical analyses are not complete. Monoterpene hydrocarbons, oxygenated monoterpenes, and oxygenated sesquiterpenes were all sign different for the three use categories. We will determine which individual compounds contribute to these differences. Estimated concentrations of unidentified compounds will also be evaluated. One assumption is that heavy browsing during 1989 and 1990 did not cause plant secondary chemistry changes which persisted in 1991. Of the 120 plants with use data for both years, 66 plants in a given use category for 1989 were in the same category in 1990 and 38 plants were in a higher category. Only 15 plants fell to a lower use category and only 1 plant dropped from Category 1 to 3. Based on these observations, degree of use was reasonably consistent for individual plants across years, suggesting that, at least between 1989 and 1990, if induction occurred, it was short term. Leaf surface chemistry appears to be related to degree of use of individual tarbush plants by livestock.

}, keywords = {Chihuahuan Desert, leaf surface, mammalian herbivory, tarbush, terpene profile}, doi = {10.1023/A:1022399426352}, url = {/files/bibliography/512.pdf}, author = {Richard E. Estell and E.L. Fredrickson and D.M. Anderson and Kris Havstad and M.D. Remmenga} } @mastersthesis {51220, title = {The thermoregulatory and reproductive behavior of the lesser earless lizard, Holbrookia maculata, at White Sands National Monument, New Mexico}, year = {1998}, note = {//NMSU,OTHER//NONE//ProCite field[12]: Not in File}, month = {1998}, pages = {128}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {Thermoregulation and reproductive behavior were examined for the lesser earless lizard, Holbrookia maculata (Phrynosomatidae), in a series of field studies from 1994 to 1997 in southcentral New Mexico. Within the range of this species is a population that inhabits the unique environment of white gypsum (CaSO4) "sand" dunes at White Sands National Monument, New Mexico. The physical properties of gypsum produce soil temperatures that are relatively cooler than adjacent non-gypsum habitats. Lower environmental temperatures could ultimately influence body temperatures and this lizard{\textquoteright}s ability to successfully thermoregulate, forage, grow, mate, and escape predation. Given this, I hypothesized that White Sands H. maculata have lower body temperatures and use the environment in different ways than conspecifics in a non-gypsum habitat. The results of this study support to this hypothesis. White Sands lizards had significantly lower body temperatures than H. maculata from a "normally-colored" population, located at the Jornada Long-term Experimental Research site. The microhabitats in which lizards were first observed correlated with body temperatures at White Sands, but not at the Jornada. Coloration was examined in both White Sands and Jornada H. maculata. Results of this work support the conditional signal hypothesis that bright female coloration signals to males two temporally separated, discrete messages that are conditional upon the degree of coloration: early in the breeding season low intensity coloration signals courtship receptivity, whereas later in the season high intensity pigmentation signals courtship rejection. It also suggests that females (a) maximize the potential for egg fertilization by stimulating courtship with low intensity coloration when eggs are ready for fertilization, and (b) reject courtship with high intensity pigmentation when carrying fertilized eggs.}, keywords = {dissertation, dissertations, lizard, Holbrookia, lizard, physiology, lizard, thermoregulation, physiology, reptiles, theses, thesis, White Sands, lizard}, author = {Hager, Stephen B.} } @article {JRN54833, title = {Transient responses of North-American grasslands to changes in climate}, journal = {Climate Change}, volume = {34}, year = {1996}, month = {10/01/1996}, pages = {269-278}, chapter = {269}, abstract = {

Our objective was to evaluate the transient responses of grasslands in the central grassland region of North America to changes in climate. We used an individual plant-based gap dynamics simulation model (STEPPE-GP) linked with a soil water model (SOILWAT) to evaluate the effects of changes in climate on the composition and structure of grassland vegetation. Five functional types of plants were simulated based upon lifeform, physiology, and rooting distribution with depth. C3 and C4 perennial grasses with either a shallow or deep rooting distribution, and deeply rooted C3 shrubs were simulated under current climatic conditions and under a GFDL climate change scenario for nine sites representative of the temperature and precipitation regimes in the grassland region.

Although vegetation at the sites responded differently to climate change, shifts in functional types occurred within 40 years of the start of the climate change. C4 grasses increased in dominance or importance at all sites with a change in climate, primarily as a result of increases in temperature in all months at all sites. The coolest sites that arc currently dominated by C3 grasses were predicted to shift to a dominance by C4 grasses, whereas sites that are currently dominated by C4 grasses had an increase in importance of this functional type with a change in climate. Current annual temperature was the best predictor of changes in C3 biomass, and C3 and C4 biomass combined; current annual precipitation was the best predictor of changes in C4 biomass. These predicted shifts in dominance and importance of C3versus C4 grasses would have important implications for the management of natural grasslands as well as the cultivation of crops in the central grassland region.

}, keywords = {changes in climate, North-American grasslands, Transient responses}, url = {https://link.springer.com/article/10.1007/BF00224638}, author = {D.P. Coffin and W. K. Lauenroth} } @article {51322, title = {Tarbush leaf surface terpene profile in relation to mammalian herbivory}, year = {1996}, note = {NOT A DUPLICATE OF RECORD $\#$474}, month = {1996}, pages = {237-241}, publisher = {US Forest Service}, edition = {Gen. Tech. Rep. INT-GTR}, abstract = {

Cattle, sheep and goats were densely stocked in pad- docks containing tarbush (Flourensia cernua DC) for six to nine days and defoliation of 160 plants was recorded daily during two years. Plants were separated into high, moderate or low defoliation categories. Leaves were collected from plants during the same stage of maturity during the third year. Leaf surface compounds were extracted with ethanol and mono- and sesquiterpenes were ana-lyzed using gas chromatography/ion trap mass spectrometry. A set of 11 variables was identified that appeared most closely related to plant defoliation categories: dry matter, ash, limonene, camphor, borneol, a copaene, B caryophyllene, a pinene, p-cymene, cis-jasmone and caryophyllene oxide concentrations. This group distinguished among all three defoliation categories (P \< 0.03) when subjected to multivariate analysis. These data support the hypothesis that leaf surface chemistry is related to degree of defoliation of individual tarbush plants by livestock.

}, keywords = {diet selection, Epicuticular wax, Flourensia cernua, leaf surface chemistry, monoterpenes, sesquiterpenes}, url = {/files/bibliography/512.pdf}, author = {Richard E. Estell and E.L. Fredrickson and D.M. Anderson and Kris Havstad and M.D. Remmenga} } @article {51329, title = {Top-down impacts on creosotebush herbivores in a spatially and temporally complex environment}, journal = {Ecology}, volume = {77}, number = {5}, year = {1996}, note = {//NMSU,USDA//LTER III//}, month = {1996}, pages = {1544-1555}, abstract = {

I studied top-down effects on creosotebush (Larrea tridentata) insect herbivores by protecting them from bird and arthropod predation. The purpose of my study was to investigate experimentally the differential and/or interactive effects of two predator guilds on herbivore densities. I performed my experiments on 24 creosotebushes at each of three sites within the Jornada Long-Term Ecological Research Site in the Chihuahuan Desert of southwestern New Mexico, USA.... I conducted these experiments and censuses in 1993 and again in 1994. In both years the herbivore densities became significantly higher in experimental than in control creosotebushes. The effects of bird and arthropod predation on herbivore densities were additive in 1993, but they were compensatory in 1994.

}, keywords = {arthropod predation, article, articles, avian predation, herbivores, arthropod, herbivory, Larrea, journal, journals, Larrea, herbivores}, doi = {10.2307/2265550 }, url = {files/bibliography/JRN00226.pdf}, author = {Floyd, Ted} } @proceedings {51355, title = {Tracking environmental change with the desert shrub ocotillo (Fouquiera splendens): Prospects and pitfalls}, volume = {Gen. Tech. Rep. INT-GTR-338}, year = {1996}, note = {//LOCAL,NMSU//NONE//ProCite field[6]: InProCite field[8]: Compilers}, month = {May 23-25, 1995}, pages = {224-229}, publisher = {U.S. Department of Agriculture, Forest Service, Intermountain Research Station}, address = {Las Cruces, NM}, abstract = {Ocotillo is a drought-deciduous desert shrub capable of orchestrating rapid morphological and physiological adjustments to changes in environmental conditions. Lengths of over 2,500 stem segments from two populations of ocotillo growing in the Chihuahuan Desert were measured to explore the possibility that episodes of stem growth could be used to infer past environmental change. Stem growth was so intermittent and complex that historical projections of environmental conditions were not possible without first establishing benchmark stem segments. Once established though, benchmark stem segments and subsequent stem growth may be used as easily measurable integrators of ongoing environmental change in desert ecosystems.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, Fouquieria, environmental change, ocotillo, SEE , plant, environmental change, proceeding, proceedings, technique, environmental change, technique, Fouquieria}, author = {K.T. Killingbeck}, editor = {J.R. Barrow and McArthur, E.D. and R. E. Sosebee and R. J. Tausch} } @proceedings {51359, title = {Time series satellite data to identify vegetation responses to stress as an indicator of ecosystem health}, volume = {General Technical Report INT-GTR-338}, year = {1996}, month = {May 23-25, 1995}, pages = {255-261}, publisher = {USDA Forest Service, Intermountain Research Station, Gen. Tech. Rep. INT-GTR-338}, address = {Las Cruces, NM}, abstract = {

One measure of health in an ecosystem is the response of that ecosystem to an environmental perturbation (such as rain) over time. Healthy and unhealthy systems may have different phenological response patterns. Grassland and shrub land sites were selected, and metrics derived from temporal profiles of vegetation index values from Advanced Very High Resolution Radiometer satellite data from 1987 through 1993. The temporal profiles show that the vegetation types may be statistically discriminated, and metric values demonstrate different responses to rainfall.

}, url = {/files/bibliography/498.pdf}, author = {J. Lancaster and D. A. Mouat and Kuehl, R.O. and Walter G. Whitford and D. J. Rapport}, editor = {J.R. Barrow and McArthur, E. Durant and R. E. Sosebee and R. J. Tausch} } @proceedings {51365, title = {Time series analysis of data from raingage networks in the Southwest}, volume = {General Technical Report INT-GTR-338}, year = {1996}, month = {May 23-25, 1995}, pages = {43-47}, publisher = {USDA Forest Service, Intermountain Research Station, Gen. Tech. Rep. INT-GTR-338}, address = {Las Cruces, NM}, abstract = {

The ability to evaluate shrubland ecosystem dynamics in a changing environment requires a historical perspective and quantitative analysis of one of the primary ecosystem inputs, precipitation. Historical time series of precipitation data collected from 25 raingages on the USDA Jornada Experimental Range since as early as 1915 are examined. Time series analyses are conducted to test for trends, autocorrelation, and periodicities in the data and establish an association between mean annual precipitation and time. These results are compared with precipitation data from the Walnut Gulch Experimental Watershed and records from 25 raingages on the Santa Rita Experimental Range in Southeastern Arizona. Because segments of the historic record analyzed can reveal increasing annual precipitation, decreasing annual precipitation, or no trend in annual precipitation, caution must be exercised in attempting to assign either natural variations in weather and climate or rangeland use and management practices as the cause of changes in vegetation over time.

}, url = {/files/bibliography/501.pdf}, author = {M. H. Nichols and Lane, L.J. and Gibbens, Robert P.}, editor = {J.R. Barrow and McArthur, E. Durant and R. E. Sosebee and R. J. Tausch} } @book {51409, title = {Temporal and spatial variability as neglected ecosystem properties: Lessons learned from 12 North American ecosystems}, series = {Evaluating and Monitoring the Health of Large-scale Ecosystems}, year = {1995}, note = {//NMSU//LTER III//ProCite field[6]: In}, month = {1995}, pages = {359-383}, publisher = {Springer-Verlag}, organization = {Springer-Verlag}, address = {NY}, abstract = {

Evaluating and monitoring the {\textquotedblleft}health{\textquotedblright} of large-scale systems will require new and innovative approaches. One such approach is to look for ecological signals in the structure of ecological variability observed in space and time. Such variability is sometimes considered something to minimize by clever sampling design, but may in itself contain interesting ecological information (Kratz et al. 1991). In fact, much of ecology can be considered an attempt to understand the patterns of spatial and temporal variability that occur in nature and the processes that lead to these patterns. Despite widespread interest in patterns of variation there have been relatively few attempts to describe comprehensively the temporal and spatial variation exhibited by ecological parameters. As a result, we have no general laws that allow us to predict die relative magnitude of temporal and spatial variability of different types of parameters across the full diversity of ecological systems. Even within single ecosystems, understanding of the interplay between temporal and spatial variability is lacking. For example, Lewis (1978) noted that despite a large literature, the relation between temporal and spatial variability in plankton distribution within a lake is not well understood. Matthews (1990) makes a similar point regarding fish communities in streams.

}, keywords = {book, books, chapter, chapters, ecosystem health, report, reports}, doi = {10.1007/978-3-642-79464-3_23 }, url = {files/bibliography/JRN00198_0.pdf}, author = {T. K. Kratz and J. J. Magnuson and Bayley, P. and Benson, B. J. and Berish, C. W. and Bledsoe, C. S. and Blood, E. R. and Bowser, C. J. and S. R. Carpenter and Gary L. Cunningham and Dahlgren, R. A. and T. M. Frost and Halfpenny, J. C. and Hansen, J. D. and Heisey, D. and Inouye, R. S. and Dawn M. Kaufman and McKee, A. and Yarie, J.}, editor = {D. J. Rapport and C. Gaudet and P. (eds.) Calow} } @conference {51418, title = {Time series analysis of data from raingage networks in the Southwest}, booktitle = {Wildland Shrub Symposium}, year = {1995}, month = {May 23-25, 1995}, pages = {3}, abstract = {

The ability to evaluate shrubland ecosystem dynamics in a changing environment requires a historical perspective and quantitative analysis of precipitation as one of the primary ecosystem inputs. Historical time series of precipitation data collected from 24 raingages on the USDA Jornada Experimental Range since 1915 are examined. Time series analyses are conducted to test for trends, autocorrelation, and periodicities in the data and, thereby, an association between mean annual precipitation and time. These results are compared with precipitation data from the Walnut Gulch experimental Watershed in Southeastern Arizona and precipitation data collected over the southwestern region of the United States. Because segments of the historic record analyzed can reveal increasing annual precipitation, decreasing annual precipitation, or no trend in annual precipitation, caution must be exercised in attempting to assign either natural variations in weather and climate or rangeland use and management practices as the cause of changes in vegetation over time.

}, author = {M. H. Nichols and Lane, L.J. and Gibbens, Robert P.} } @proceedings {51486, title = {Technologies for sustainable development of Chihuahuan Desert rangelands}, volume = {12}, year = {1993}, month = {1993}, abstract = {Options for management of Chihuahua Desert rangelands have been recently viewed as limited. Many technologies that had typically been seen as viable components of management have become expensive, inefficient, or inappropriate. Yet, the need for management of these desert rangelands is increasingly urgent. It is evident that simply withdrawing lands from use will not generally lead to improvements in resource values or restoration of prior condition. Human interventions are required, but the nature of those interventions must be based on knowledge of the ecological integrity of these lands. We view the northern Chihuahuan Desert as a complex and chaotic system. Management tools must be viewed as triggers for change within this complexity rather than obtrusive instruments for large scale alterations to the landscape. One trigger mechanism is domestic livestock. Planned manipulations of livestock grazing behaviors may achieve desirable changes in vegetation structure. Another trigger is selective reintroduction of germplasm. Seed dispersal technologies which rely on natural elements, such as animal, wind, and water, may slowly affect bioremediation with minimal impacts to other resources and with minimal expense. Development of these look requires detailed process level knowledge of the desert ecosystem. We are beginning to achieve this understanding through interdisciplinary and interinstitution research. However, we need to further expand these collaborations, especially internationally, to best develop livestock and revegetation tools that will be applicable for sustainable development throughout the Chihuahuan Desert.}, keywords = {Chihuahuan Desert, rangelands, sustainable development}, author = {Kris Havstad} } @article {51504, title = {Tobosa tiller defoliation patterns under rotational and continuous stocking}, journal = {Journal of Range Management}, volume = {46}, number = {6}, year = {1993}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {1993}, pages = {500-505}, abstract = {

Stocking growing tobosa using high animal numbers for short periods followed by adequate rest may improve forage utilization and harvest efficiency. Four periods were monitored to investigate frequency and intensity of individual tiller defoliation in relation to grazing pressure under high-density, seasonal rotational and low-density, continuous stocking. From 34 to 38\% of tiller height and 40 to 45\% of tiller leaf material was removed per period in the rotational treatment while intensity of defoliation per grazing event remained consistent. In the continuous treatment, amount of tiller removed ranged from 11 to 88\% and was not consistent over four periods. In both stocking treatments, increment of tiller and number of leaves removed per grazing event was negatively correlated (P \< 0.01) with tiller height before grazing. Marked tiller utilization in the rotational treatment was always greater than that in the continuous treatment. Percentage of tillers defoliated in the rotational treatment ranged from 88\% to 95\%. In contrast, percentage of tillers defoliated in the continuous treatment was always less than 30\% during all grazing periods. During growth, probability that a tiller would be grazed at least once in the rotational treatment was more than twice as great as in the continuous treatment. However, within the rotational treatment, probability of multiple grazing events (\> 2) on an individual tiller was less than probability of a tiller being grazed just once. Probability of a tiller remaining ungrazed early in the season was less (P \< 0.05) than later in the season for both treatments. High density rotational stocking promoted more efficient and uniform utilization of tobosa than low-density continuous stocking.

}, keywords = {Animal husbandry, defoliation, forage, grasses, Grazing intensity, grazing management, pastures, range management, rotational grazing, Tillers}, doi = {10.2307/4002860 }, url = {/files/bibliography/410.pdf}, author = {R.S. Senock and D.M. Anderson and L. W. Murray and G.B. Donart} } @article {51512, title = {Technical note: Automatic sorting of free-ranging cattle}, journal = {Journal of Range Management}, volume = {45}, number = {3}, year = {1992}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {1992}, pages = {312-314}, abstract = {

An automated system to weigh and sort free-ranging cattle was adapted to administer cottonseed pellets (41\% crude protein) to free-ranging cattle. The frequency with which animals drank water determined the interval between supplemental feedings. The automatic spacing of individual animals was the weakest link in the chain of events leading to the sorting of cattle into groups to administer treatments. Periodically during the study, free-standing water was available due to above-average precipitation. This resulted in an inconsistent supplementation schedule because animals did not have to return through the maze to drink water. Single herd management eliminated potential pasture-treatment confounding but accentuated individual animal behavior which resulted in a range of supplement intakes and drinking water patterns.

}, keywords = {automation, body weight, cattle, cattle feeding, cottonseed protein, dietary supplements, drinking, free range husbandry, sorting, weight determination}, url = {/files/bibliography/379.pdf}, author = {D.M. Anderson and R. R. Rouda and L. W. Murray and Pieper, Rex D.} } @article {51567, title = {Two-phase pattern in mesquite-herbland vegetation in southwestern New Mexico}, journal = {The Southwestern Naturalist}, volume = {36}, number = {1}, year = {1991}, note = {//NMSU//NONE//}, month = {1991}, pages = {54-59}, abstract = {Vegetation on upland sites in southern New Mexico is represented by a mosaic pattern composed of scattered mesquite (Prosopis glandulosa) plants and associated understory plants, interspersed in open herbland composed of various grasses and forbs. Bush muhly (Muhlenbergia porteri) was the main grass species occurring under mesquite canopies. Purslane portulaca (Portulaca oleracea) was the only forb species showing a positive correlation with mesquite canopy cover. Abundance of other grass and forb species was greater at the mesquite periphery or in the open areas than under the mesquite canopies. Black grama (Bouteloua eriopoda) was distributed in open herbland between trees.}, keywords = {article, articles, grassland, Prosopis-herbland vegetation, journal, journals, Prosopis, plant associations, Prosopis-herbland vegetation, vegetation,Prosopis-herbland}, author = {Haque, Zahoorul and Amade Younga and K. C. McDaniel and Pieper, Rex D.} } @article {51587, title = {Time series analysis of soil moisture and rainfall along a line transect in arid rangeland}, journal = {Soil Science}, volume = {152}, number = {3}, year = {1991}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1991}, pages = {189-198}, abstract = {

Soil water content and rainfall were measured at 30 m intervals along a 2730 m transect on the New Mexico State University College ranch, 40 km northeast of Las Cruces. The data were collected at 2-week intervals. Time-series techniques (autocorrelations and cross-correlations) were used to examine the relationships between the water content and rainfall and to compare the relationship of the overall average (the entire transect soil moisture content with that individual transect segments. Correlograms indicated the range of dependence in time for soil moisture and rainfall was different for the entire transect when compared to individual transect segments. In general, water content showed a significant correlation in time between 3 to 5 lags, whereas rainfall showed a significant correlation in time between 2 and 25 lags. Soil moisture lagged behind rainfall by a few lags. The response time to rainfall was short in the surface soil but increased with depth to as much as 10 lags at 135 cm. Wetting of dry, arid rangeland soils is a slow process and is largely a function of antecedent water content. In addition, this wetting process pattern was different for the entire transect when compared to individual transect segments.

}, keywords = {article, articles, journal, journals, precipitation,transect, rainfall, SEE , soil moisture, technique, time-series analysis, time-series analysis, transect, time-series analysis, transect,precipitation, transect,soil moisture}, doi = {10.1097/00010694-199109000-00005}, author = {M. S. Nash and Peter J. Wierenga and Gutjahr, Allan} } @mastersthesis {51670, title = {Tiller defoliation of Hilaria mutica (Buckl.) Benth. under seasonal high-density rotation and continuous stocking}, year = {1989}, note = {//NMSU//NONE//}, month = {1989}, pages = {68}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Hilaria mutica (Buckl.) Benth. commonly called tobosa, is a warm-season, native perennial grass. Spread of this grass under arid conditions occurs mainly from rhizomes. Tobosa was seasonally grazed with cattle under high-density (4.83 AU/ha) rotation and low-density (0.35 AU/ha) continuous management strategies in 1986 and 1987 to evaluate patterns of utilization. Each year 80 tillers were monitored under each grazing strategy to evaluate frequency and intensity of defoliation. Under high-density rotational grazing, 92\% of the tillers were grazed at least once with a mean height reduction of 31\% or 53 mm and an average of 2 leaves removed per tiller. Under low-density continuous grazing only 29\% of the tillers were grazed at least once. This resulted in a 14\% mean reduction in tiller height or 25 mm mean height reduction and one leaf removed per grazing event. There were a similar number of tillers defoliated at least once in 1986 (51\%) compared to 1987 (65\%), averaged over both treatments within years. These defoliations contributed to a mean height reduction of 41\% or 3 leaves/tiller removed in 1986 compared to a height reduction of 12\% or 2 leaves/tiller removed in 1987. During the first grazing cycle, 55\% of the tillers averaged over grazing strategies and years were grazed more than once. This contributed to a mean plant height reduction of 27\% or 49 mm compared to 61\% of the tillers being grazed more than once (36\% reduction or 53 mm) during the second grazing cycle. The overall correlation coefficient (r = 0.26) indicated height removed did not affect number of leaves removed. Nevertheless, high-density rotation stocking increased frequency and intensity of defoliation. Between grazing cycles in 1987, mean plant height decreased 29 mm under low-density stocking compared to a mean increase in plant height of 68 mm under high-density stocking. The mean number of green leaves decreased by 1 under low-density stocking compared to high-density stocking in which there was a mean increase of 1. The mean number of brown leaves per culm was greater under high-density stocking (1) compared to low-density stocking (<1).}, keywords = {cattle grazing, tiller defoliation, cattle, stocking strategies, dissertation, dissertations, grass, tiller defoliation, Hilaria, tiller defoliation, range management, theses, thesis}, author = {Kone, Daouda} } @article {51686, title = {Temporal patterns of microarthropod population densities in fluff grass (Erioneuron pulchellum) litter: relationship to subterranean termites}, journal = {Pedobiologia}, volume = {33}, year = {1989}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1989}, pages = {333-338}, abstract = {

In most of the hot desert areas of North America, fluff grass, Erioneuron pulchellum is the most common perennial grass in desert shrub habitats. E. pulchellum is heavily utilized by subterranean termites (Whitford et al., 1982). As part of a study to examine faunal effects on the decomposition of E. pulchellum litter (Silva et al., 1985), we studied the sequence of microarthropod colonization and seasonality of microarthropod populations in E. pulchellum litter. These data provide a useful comparison with data on shrub litter microarthropod fauna and allow an assessment of effects of subterranean termite activity on that fauna. Experimental studies by Steinberger et al. (1984) demonstrated that the population densities of microarthropods vary as a function of the quantity of litter. Whitford et al. (1982), Silva et al.(1985) and Whitford et al.(1988) showed that in the Chihuahuan Desert, subterranean termites remove at least 50\% of the annual above ground dry matter production. Based on these observations we hypothesized that termites could substantially reduce suitable habitat for microarthropods hence competitively reduce population sizes of microarthropods. Here we report the results of studies designed to test these hypotheses.

}, keywords = {article, articles, decomposition, microarthropods, decomposition, termites, Erioneuron,microarthropods, grass,decomposition, journal, journals, litter,Erioneuron, microarthropod,population density, microarthropod,temporal patterns, termite,decomposition}, url = {files/bibliography/89-Ped-Whitford.pdf}, author = {Solange Silva and William P. MacKay and Walter G. Whitford} } @mastersthesis {51765, title = {A tobosa grass-burro grass mosaic community pattern in the northern Chihuahuan desert}, year = {1987}, note = {//??//NONE//}, month = {1987}, pages = {75}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, grassland community, Hilaria-Scleropogon, Hilaria,community pattern, Scleropogon, community pattern, theses, thesis}, author = {Devine, Donald L.} } @conference {51806, title = {Time budgets of free-ranging cattle}, booktitle = {39th Annual Meeting, Society for Range Management}, year = {1986}, month = {1986}, pages = {142}, abstract = {Vibracorders were used to periodically monitor periods of activity and inactivity on Hereford and Hereford-Santa Gertrudis crossbred cows grazing mesquite dune rangeland pastures 3,500 ha in size. Discussion of the data includes the correlation of periods of activity and inactivity with sunrise and sunset times. Implications of the data{\textquoteright}s use in designing grazing strategies and in conducting behavior research will be addressed.}, author = {D.M. Anderson and Richards, W.A.} } @inbook {51915, title = {Techniques in early weaning of lambs}, booktitle = {Sheep and Goat Handbook}, year = {1984}, month = {1984}, pages = {353-358}, publisher = {Winrock International, Westview Press}, organization = {Winrock International, Westview Press}, address = {Boulder, CO}, abstract = {

The only justifiable reason for early weaning of lambs is to improve the overall efficiency of the production system. It can be more efficient to put the feedstuffs directly into the lamb, rather than indirectly through the ewe in the form of milk. Increased efficiency in this case is dependent on the physiological age of the lamb, the relative costs of the two ewe diets, the costs of the lamb diet, the rate of gain of the lamb, and other benefits that might accrue, such as earlier marketing of lambs while the price is higher, enhanced opportunity to rebreed the ewe for a second lamb crop, and the opportunity to operate a larger production unit without increasing acreage.

}, url = {/files/bibliography/265.pdf}, author = {Clarence V. Hulet}, editor = {Baker, F.H. and M. Miller} } @article {51989, title = {A two-step sampling technique for estimating standing crop of herbaceous vegetation}, journal = {Journal of Range Management}, volume = {35}, number = {5}, year = {1982}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {September 1, 198}, pages = {675-677}, abstract = {Standing crop of vegetation may be estimated by sampling foliar cover per unit area and then determining mass per unit of cover. Multiplying foliar cover per unit area by mass per unit of cover gives mass per unit area (standing crop). By this method, standing crop is estimated rapidly with low variance while minimizing the amount of actual harvesting required. Standing crop of both major and minor species can be estimated adequately without over sampling major species and under-sampling minor species. The technique is most easily applied to herbaceous plant communities of low stature.}, keywords = {herbaceous vegetation, standing crop estimation, two-step sampling}, url = {/files/bibliography/212.pdf}, author = {D.M. Anderson and Kothmann, M.M.} } @article {51995, title = {Temporal and spatial resource partitioning in a Chihuahuan Desert lizard community}, year = {1982}, note = {//NMSU//NONE, LTER//ProCite field[6]: In}, month = {1982}, pages = {121-127}, institution = {U. S. Fish and Wildlife Service}, abstract = {

Actvity patterns of the lizards in a Chihuahuan Desert creosotebush (Larrea tridentata) community were studied by walking fixed transects on a marked grid and recording activity of individual lizards. We found considerable spatial overlap in Cnemidophorus tigris and Holbrookia texana; however, individuals that overlapped spatially were active at different times. We distinguished five distinct activity patterns in C. tigris and H. texana, whereas Uta stansburiana, Sceloporus magister, Phrynosoma modestum, P. cornutum, and Crotaphytus wislizenii were bimodal. Individual activity patterns varied; some were active only in the morning, only in midday, only in the afternoon, morning and afternoon, or all day. Most lizards were active less than 25\% of the days of observations. Exceptions were a few large male H. texana that were active between 40\% and 70\% of the days. We suggest that temporal separation of activity reduces intraspecific competition and increases carrying capacity in species for which food is probably not a limiting resource.

}, keywords = {book, books, chapter, chapters, Larrea community,lizard activity, lizard, Cnemidophorus, lizard, Crotaphytus, lizard, Holbrookia, lizard, Phrynosoma, lizard, Sceloporus, lizard, Uta, lizard,activity patterns, report, reports}, isbn = {Wildlife Research Report 13}, url = {files/bibliography/JRN00002_0.pdf}, author = {Creusere, F. Michael and Walter G. Whitford}, editor = {Scott, N. J. Jr.} } @conference {52058, title = {Toxicological evaluation of sewage product fed to beef cows with dormant forage}, booktitle = {American Society of Animal Scientists}, year = {1981}, month = {1981}, author = {Geoffrey Smith and Ward, R.G. and C.H. Herbel and Trujillo, P.A. and Helton, E.D.} } @article {52083, title = {Termites, microarthropods and the decomposition of senescent and fresh creosotebush (Larrea tridentata) leaf litter}, journal = {Journal of Arid Environments}, volume = {3}, year = {1980}, note = {//NMSU//US-IBP//}, month = {1980}, pages = {63-68}, abstract = {

Weight loss of fresh and senescent creosotebush (Larrea tridentata) leaves was studied during September and October, which is normally the peak of surface feeding by subterranean termites. Termites built galleries in 87.5 per cent of the bags of senescent litter and in 12.5 per cent of the bags of fresh litter. There was no significant weight loss attributable to termites. Senescent litter lost more weight than fresh litter but this was reversed during a period of abnormally high rainfall. It is suggested that this results from the presence of allelochemics in fresh litter and leaching of these compounds with high precipitation.

}, keywords = {article, articles, decomposition, Larrea litter, decomposition,microarthropod, decomposition,termite, Gnathemitermes, Larrea decomposition, journal, journals, litter,Larrea decomposition, microarthropod, Larrea decomposition, termite,Larrea decomposition}, doi = {10.1016/S0140-1963(18)31675-6}, url = {files/bibliography/80-JnlArdEnvnmts-Whitford.pdf}, author = {Harold G. Fowler and Walter G. Whitford} } @article {52126, title = {A tour of East German agriculture}, journal = {Rangelands}, volume = {1}, year = {1979}, month = {1979}, pages = {9-11}, abstract = {

In May and June of 1977, following the 13th International Grassland Congress in Leipzig, East Germany (German Democratic Republic), we toured several of the country{\textquoteright}s agricultural centers. We visited state and cooperative farms, research centers, and schools for grassland and animal management. English-speaking guides gave us information about East Germany farming, forestry, livestock, pasture and forage, and wildlife and fish. In this paper we present a digest of that information.

}, keywords = {East German agriculture, tour}, url = {/files/bibliography/172.pdf}, author = {Pearson, H.A. and C.H. Herbel and Pendleton, D.} } @article {52130, title = {Territorial behavior of Bootettix argentatus Bruner (Orthoptera: Acrididae)}, journal = {The American Midland Naturalist}, volume = {102}, number = {1}, year = {1979}, note = {//LOCAL//US-IBP//}, month = {1979}, pages = {182-184}, abstract = {

At low male densities territorial behavior was observed in male creosotebush grasshoppers (Bootettix argentatus Bruner). Males defend individual shrubs or shrub complexes and exclude conspecific males. Experimental introduction of males into occupied shrubs resulted in a maximum of one male per shrub. Aggressive interactions between males occurred more frequently in shrubs also harboring females. A hypothesis relating behavior and density to host plant condition is discussed.

}, keywords = {article, articles, behavior,grasshopper, grasshopper,behavior, grasshopper,Bootettix, journal, journals, Larrea,grasshopper}, url = {files/bibliography/79-TheAmMidldNat-Whitford.pdf}, author = {Schowalter, T. D. and Walter G. Whitford} } @mastersthesis {52155, title = {Thermal ecology of the nocturnal snake, Arizona elegans and the diurnal snake, Masticophis flagellum: Factors influencing activity}, year = {1978}, note = {//NMSU//NONE//}, month = {1978}, pages = {40}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {There were significant differences in heat gain between live and dead Masticophis flagellum, but no difference in either heat loss or heat gain in Arizona elegans. Field observations of the daily activity patterns of M. flagellum showed that in habitat with sufficient shade (cover) snakes feed during mid-day but in habitats with sparse shade snakes retired to burrows during mid-day. M. flagellum was a sit-and-wait predator in the shaded environment, and an active-search predator in open habitat. Capture success was greater and handling time shorter in shaded habitat than in open habitat. A. elegans had similar activity patterns and feeding in shaded and sparsely shaded habitats. Feeding in borrows and rodent dens allowed A. elegans to feed on diurnal lizards. Activity patterns of A. elegans in the spring and fall were affected by substrate-air temperature differences.}, keywords = {dissertation, dissertations, snake, Arizona, snake, behavior, snake, Masticophis, snake, thermal ecology, theses, thesis}, author = {Jones, Kenneth Bruce} } @article {52220, title = {Temporal fluctuations in density and diversity of desert rodent populations}, journal = {Journal of Mammalogy}, volume = {57}, number = {2}, year = {1976}, note = {//NMSU//US-IBP//}, month = {1976}, pages = {351-369}, abstract = {

Species composition and density were studied in two areas on a watershed in the Chihuahuan Desert in southern New Mexico. The upper portion of the watershed, a creosotebush community, supported \"resident\" populations of Dipodomys merriami, Perognathus penicillatus, Neotoma sp., and Onychomys torridus. The lower portion of the watershed, which drained into a grass-covered dry lake, supported Sigmodon hispidus, Reithrodonomys megalotis, Dipodomys ordii, and Spermophilus spilosoma, in addition to the species found in the creosotebush area.... Changes is species diversity in tie was correlated with rainfall and productivity. The dynamics of these Chihuahuan Desert rodent communities are considered in terms of immigration and extinction as the suitability of habitat islands change through time.

}, keywords = {article, articles, community, rodents, demography,rodents, Dipodomys,demography, journal, journals, Neotoma,demography, Perognathus,demography, rodent,demography, rodent,Dipodomys, rodent,Neotoma, rodent,Perognathus, rodent,population dynamics}, doi = {10.2307/1379694}, url = {files/bibliography/76-Journal of Mammalogy-Whitford.pdf}, author = {Walter G. Whitford} } @proceedings {52240, title = {Towards achieving a realistic simulation of a desert ecosystem}, year = {1975}, note = {//NMSU//NONE//ProCite field[6]: In}, month = {1975}, pages = {961-972}, publisher = {AFIPS Press}, keywords = {abstract, abstracts, computer simulation, conference, conference proceedings, conferences, desert ecosystem, model, desert ecosystem, proceeding, proceedings}, author = {J. Ludwig} } @article {52292, title = {Twin spots on leaves of homozygous cotton plants}, journal = {The Journal of Heredity}, volume = {64}, year = {1973}, month = {1973}, pages = {222-226}, keywords = {cotton, homozygous}, url = {/files/bibliography/99-005.pdf}, author = {J.R. Barrow and H. K. Chaudhari and M.P. Dunford} } @conference {52455, title = {Temperature and moisture effects on seedling emergence and initial growth of range plants}, booktitle = {Agronomy Abstracts}, year = {1967}, month = {1967}, pages = {40}, keywords = {initial growth, moisture, seedling emergence, temperature}, author = {R. E. Sosebee and C.H. Herbel} } @article {52466, title = {Tarbush [Flourensia cernua (DC.)]}, year = {1966}, month = {1966}, pages = {38 }, publisher = {U.S. Department of Agriculture and U.S. Department of the Interior, Chemical Control of Range Weeds, Interagency Report}, abstract = {Tarbush, a member of the composite family (sunflower tribe), is a common deciduous shrub, usually less than 3 feet tall, that grows on an estimated 13,250,000 acres from western Texas to southeastern Arizona. It generally invades on the more productive flood plain sites and spreads from seed. As it gains dominance, forage production is greatly reduced. Tarbush is practically worthless for browsing. Individual plant treatments with fenuron pellets, monuron powder, fenuron-trichloroacetate (TCA) granules, and monuron-TCA granules have consistently given plant kills in excess of 90 percent. Trichlorobenzoic acid granules have been less effective. An effective rate is an individual plant treatment of 2 grams active ingredient of fenuron pellets, monuron powder, fenuron-TCA granules, or monuron-TCA granules. The materials should be scattered around the base of the plant. Since these materials are desensitized by light and high temperatures, it is important that they be applied just before or early in an expected rainy season. This method is economical in controlling sparse stands of tarbush. It would be especially beneficial in areas where tarbush is invading grassland. The work reported was done on a silt loam soil in southern New Mexico.}, keywords = {description, Flourensia cernua, government publication, plant treatment, tarbush}, url = {/files/bibliography/097.pdf}, author = {C.H. Herbel} } @article {52512, title = {A "two-gun" ground sprayer}, journal = {Weeds}, volume = {9}, year = {1961}, month = {1961}, pages = {656-657}, abstract = {The most economical time to control invading noxious shrubs is at an early stage in the invasion when stands are sparse. One method of doing this is with a ground spray rig. With such a rig the problem is to get the guns out from the vehicle so a reasonably sized swath can be covered. The outrigger apparatus described herein can be used to cover a swath of 50 feet where the brush is fairly dense to 90 feet on sparser stands.}, keywords = {control invading noxious shrubs, ground sprayer}, url = {/files/bibliography/085.pdf}, author = {C.H. Herbel and F.N. Ares} } @article {52514, title = {Trends in carrying capacity and vegetation on an arid Southwestern range}, journal = {Journal of Range Management}, volume = {14}, number = {2}, year = {1961}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {March 1, 1961}, pages = {78-83}, abstract = {Cattle ranchers of the Southwest are confronted with an ever-changing forage resource. This means they must make continual adjustments in their ranch operations. It is not easy to sell all or part of a herd that has been developed through years of selective breeding and care. However, pressure to do so often faces the Southwestern rancher. In addition, there are insidious changes in the range vegetation that are not apparent except where they have been carefully documented by objective, long-term records. Some of these fluctuations and changes that have taken place on one range area are described herein. Pertinent records have been kept at the Jornada Experimental Range in south-central New Mexico about 60 miles north of the international boundary. They include livestock numbers, cover, production of forage and nonforage plants, precipitation, wind velocity, evaporation and maximum and minimum temperatures. Range lands similar to the Jornada occupy 26 million acres, mainly in southern New Mexico and western Texas. These comprise the range areas known as the black grama (Bouteloua eriopoda Torr.) and tobosa [Hilaria mutica (Buckl.) Benth.] grasslands and associated shrub ranges.}, keywords = {carrying capacity, cattle ranches, Southwestern range, vegetaton trends}, url = {/files/bibliography/086.pdf}, author = {Paulsen, H.A., Jr. and F.N. Ares} } @article {52572, title = {Trucking vs. trailing cattle from ranch to railroad}, journal = {The Cattleman}, volume = {28}, number = {8}, year = {1942}, month = {1942}, pages = {19}, abstract = {Trucks are being used more and more to replace the trail herd on the Jornada Experimental Range. Not only are trucks used to haul market-bound cattle to the railroad but small loading chutes have been built at strategic points on the range where calves are separated from the cows and hauled in light trailers to a central point, usually the headquarters ranch. There they are assembled, worked, and weighed with the minimum of handling and are finally picked up in huge semitrailer trucks and hauled to the railroad50 to 60 head to the load, depending on the size of the animals. Trucking bids fair to become the accepted method of transporting cattle between points not served by railroads. Trailing cattle for distances over heavily grazed public driveways with water at irregular intervals and little feed available has exacted a heavy toll from the producers who are not located near shipping points.}, keywords = {trail herds, transporting cattle, trucking}, url = {/files/bibliography/058.pdf}, author = {F.N. Ares} } @article {52594, title = {Tentative range utilization standards; black grama (Bouteloua eriopoda)}, number = {Research Note 26}, year = {1938}, month = {1938}, pages = {4 }, abstract = {Refer to Research Note 25 of the Southwestern Forest and Range Experiment Station which presents the fundamental concepts underlying tentative range utilization standards. Black grama (G28) is an important forage grass on many Southwestern semidesert and shortgrass ranges. In association with tobosa (Hilaria mutica) (G71), it is the dominant type over several million acres in southern New Mexico, western Texas, southeastern Arizona and along the Rio Grande to Albuquerque. Black grama is also abundant in portions of central Arizona and in the shortgrass country of eastern New Mexico. It now occurs, or has occurred in the past, in important quantities on the Cibola, Coconino, Coronado, Crook, Gila, Lincoln, Prescott, and Tonto National Forests in the Southwest.}, keywords = {black grama, range utilization, research notes, tentative standards, tobosa}, url = {/files/bibliography/040.pdf}, author = {R.S. Campbell and Crafts, E.C.} } @article {52647, title = {Trees and shrubs of New Mexico}, year = {1913}, note = {//??//NONE//updated 8/21/2006}, month = {1913}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, chapter, chapters, list,shrubs, list,trees, report, reports, shrubs, of New Mexico, trees, of New Mexico}, isbn = {Bulletin 87}, author = {Wooton, E.O.} }