@article {JRN55373, title = {Mechanisms and drivers of alternative shrubland states}, journal = {Ecosphere}, volume = {13}, year = {2022}, month = {03 April 2022}, pages = {e3987}, abstract = {Grassland-to-shrubland state change has been widespread in arid lands globally. Long-term records at the Jornada Basin USDA-LTER site in the North American Chihuahuan Desert document the time series of transition from grassland dominance in the 1850s to shrubland dominance in the 1990s. This broadscale change ostensibly resulted from livestock overgrazing in conjunction with periodic drought and represents the classic {\textquotedblleft}grassland-to-shrubland{\textquotedblright} regime shift. However, finer-scale observations reveal a more nuanced view of this state change that includes transitions from dominance by one shrub functional type to another (e.g., based on leaf habit [evergreen vs. deciduous], N2 fixation potential, and drought tolerance). We analyzed the Jornada Basin historic vegetation data using a fine-scale grid and classified the dominant vegetation in the resulting 890 cells on each of four dates (1858, 1915, 1928, and 1998). This analysis allowed us to quantify on contrasting soil geomorphic units the rate and spatial distribution of: (1) state change from grasslands to shrublands across the Jornada Basin, (2) transitions between shrub functional groups, and (3) transitions from shrub-to-grass dominance. Results from our spatially explicit, decadal timescale perspective show that: (1) shrubland ecosystems developing on former grasslands were spatially and temporally more dynamic than has been generally presumed, (2) in some locations, shrublands initially developing on grasslands subsequently transitioned to ecosystems dominated by a different shrub functional type, with these changes in shrub composition likely involving changes in soil properties, and (3) some shrub-dominated locations have reverted to grass dominance. Accordingly, traditional, broad characterizations of {\textquotedblleft}grassland-to-shrubland{\textquotedblright} state change may be too simplistic. An accounting of these complexities and transitions from one shrub functional group to another is important for projecting state change consequences for ecosystem processes. Understanding the mechanisms, drivers, and influence of interactions between patterns and processes on transitions between shrub states defined by woody plant functional types will be germane to predicting future landscape change.}, keywords = {desertification, drylands, plant functional types, regime shifts, shrub growth form, shrubland transitions, Special Feature: Dynamic Deserts}, doi = {10.1002/ecs2.3987}, url = {files/bibliography/22-005.pdf}, author = {Steven R. Archer and Debra C. Peters and N. Dylan Burruss and Jin Yao} } @proceedings {JRN55368, title = {Mapping North America agroecosystems: A social-ecological systems approach}, year = {2022}, month = {3/30/2022}, abstract = {Mapping the types and locations of agroecoregions is useful for understanding how communities and the landscapes within which they are embedded interact. Despite the utility of these spatial approaches, a theory-driven description of agroecoregions in the continental United States (CONUS) has not been widely adopted. To help provide one such description, we outlined CONUS agroecoregions using a clustering analysis based in a social-ecological systems (SES) framework. First, we evaluated six SES frameworks for their suitability in mapping agroecoregions. Based upon our criteria, we selected the Ostrom social-ecological systems framework (SESF) to guide our selection of variables. Using a literature review and existing datasets, we identified candidate county-level variables that could represent the Tier Two SESF sub-categories in different categories (Resource System, Resource Units, Governance System, Actor). We then scored each variable based upon its applicability to the SESF with the top scoring variable in each sub-category selected for our analysis. We used these variables as inputs for our clustering and then evaluated combinations of different clustering algorithms and number of clusters. We selected the final combination based upon the interpretability its results. We mapped these clusters and interpreted the resulting agroecoregions based upon differences in the relative mean values of their Tier Two categories. As an application of this approach to identifying agroecoregions, we evaluated how these agroecoregions related to differences in SES outcomes, including human and ecosystem health. We will discuss our findings and how our approach for outlining agroecoregions can help increase understanding of landscape processes. }, keywords = {agroecosystems, approach, mapping, North America, social-ecological, systems}, author = {Zachary Hurst and D W Archer and A. W. Coffin and Tiff Van Huysen and Sarah Goslee and Katie Pisarello and J. D. Wulfhorst and S. Spiegal} } @article {JRN55345, title = {Movement, activity, and landscape use patterns of heritage and commercial beef cows grazing Chihuahuan Desert rangeland}, journal = {Journal of Arid Environments}, volume = {199}, year = {2022}, month = {01/03/2022}, pages = {104704}, abstract = {Highlights {\textbullet}Raramuri Criollo cows (heritage breed) exhibited more desirable spatial distribution patterns (traveled farther, spent more time grazing and traveling, and explored larger areas of the pasture) than commercial beef breed counterparts. {\textbullet}Breed differences in resource selection and utilization were largest during the dormant season. {\textbullet}Raramuri Criollo (heritage breed) could have a lighter footprint on desert rangeland compared to Angus Hereford crossbred (commercial breed) cattle. The objective of this study was to compare foraging behavior of mature Raramuri Criollo (RC, heritage breed) and Angus Hereford crossbred (AH, commercial breed) cows grazing Chihuahuan Desert rangeland during summer and winter in three consecutive years. Movement, activity, and spatial distribution variables were calculated from 10-min interval GPS positions of 5{\textendash}11 randomly selected cows of each breed. Thirteen pasture pixel attributes were used to analyze grazing utilization and selection patterns of both breeds. Statistical mixed models were used to determine the effects of breed and season on all foraging response variables. Spatial regression analysis was used to examine resource utilization. Compared to AH, RC cows traveled farther at higher velocity rates, spent less time resting, more time grazing and traveling, explored larger areas as individuals, and exhibited lower herd cohesion. The RC herd explored more grazing patches (30-m pixel) overall and exhibited lower patch residence times in winter, a foraging strategy linked with lighter environmental footprint. During summer, similar pixel variables explained re-visitation rates of cows of both breeds. Both breeds avoided areas far from water, but RC cows showed higher avoidance of pixels farther out from a drinker during the dormant season. RC cows appeared to exhibit a keener ability to select patches with differing surface temperature, and greenness compared to AH counterparts. RC cows showed higher preference for pixels with high shrub density than AH counterparts in summer. During the dormant season, AH cows exhibited a strong preference for black grama patches, a species with high ecological value, and higher avoidance of patches with high density of other grasses. Differences in foraging behavior documented in this study support the hypothesis that RC cattle could impose a lighter footprint on desert rangeland relative to commonly raised commercial beef cattle.}, keywords = {beef cattle, foraging behavior, GPS tracking, habitat selection, Raramuri Criollo}, doi = {10.1016/j.jaridenv.2021.104704}, url = {files/bibliography/22-003.pdf}, author = {S. Nyamuryekung{\textquoteright}e and Andr{\'e}s F. Cibils and Richard E. Estell and D. VanLeeuwen and S. Spiegal and Caitriana Steele and Amy L. Gonzalez and Matthew M. McIntosh and Qixu Gong and Huiping Cao} } @article {JRN55380, title = {Measuring the social and ecological performance of agricultural innovations on rangelands: Progress and plans for an indicator framework in the LTAR network}, journal = {Rangelands}, year = {2022}, month = {1/7/2022}, pages = {1-11}, abstract = {On the Ground {\textbullet} The Long-Term Agroecosystem Research Network launched the LTAR Agricultural Performance Indicator Framework to evaluate how agricultural innovations perform relative to sustainable intensification goals in five domains: Environment, Productivity, Economic, Human Condition, and Social. {\textbullet} Here we describe our progress and plans for measuring the performance of agricultural innovations on rangelands. {\textbullet} We present a method for measuring outcomes of management innovations against site-specific benchmarks, which can be applied in grazinglands worldwide. {\textbullet} LTAR typically studies management on fine scales (ecological site, ranch); how to measure effects on broad scales (landscape, community) remains a persistent question. {\textbullet} LTAR{\textquoteright}s Agricultural Performance Indicator Framework will evolve with stakeholder engagement.}, keywords = {Agricultural performance indicators, Benchmarks, Collaborative approaches, Coupled human-natural systems, Long-Term Agroecosystem Research Network (LTAR), Sustainable intensification}, doi = {10.1016/j.rala.2021.12.005}, url = {files/bibliography/22-011.pdf}, author = {S. Spiegal and Nicholas Webb and Elizabeth H. Boughton and Raoul K. Boughton and Amanda Bentley Brymer and Patrick E. Clark and Chandra D. Holifield Collins and David L. Hoover and N. E. Kaplan and Sarah McCord and Meredith Gwendwr and Lauren M. Porensky and David P. Toledo and Hailey Wilmer and J. D. Wulfhorst and Brandon T Bestelmeyer} } @article {JRN55316, title = {Monitoring agroecosystem productivity and phenology at a national scale: A metric assessment framework}, journal = { Ecological Indicators}, volume = {131}, year = {2021}, month = {8/27/2021}, chapter = {108147}, abstract = {Effective measurement of seasonal variations in the timing and amount of production is critical to managing spatially heterogeneous agroecosystems in a changing climate. Although numerous technologies for such measurements are available, their relationships to one another at a continental extent are unknown. Using data collected from across the Long-Term Agroecosystem Research (LTAR) network and other networks, we investigated correlations among key metrics representing primary production, phenology, and carbon fluxes in croplands, grazing lands, and crop-grazing integrated systems across the continental U.S. Metrics we examined included gross primary productivity (GPP) estimated from eddy covariance (EC) towers and modelled from the Landsat satellite, Landsat NDVI, and vegetation greenness (Green Chromatic Coordinate, GCC) from tower-mounted PhenoCams for 2017 and 2018. Overall, our analysis compared production dynamics estimated from three independent ground and remote platforms using data for 34 agricultural sites constituting 51 site-years of co-located time series. Pairwise sensor comparisons across all four metrics revealed stronger correlation and lower root mean square error (RMSE) between end of season (EOS) dates (Pearson R ranged from 0.6 to 0.7 and RMSE from 32.5 to 67.8) than start of season (SOS) dates (0.46 to 0.69 and 40.4 to 66.2). Overall, moderate to high correlations between SOS and EOS metrics complemented one another except at some lower productivity grazing land sites where estimating SOS can be challenging. Growing season length estimates derived from 16-day satellite GPP (179.1 days) were significantly longer than those from PhenoCam GCC (70.4 days, padj < 0.0001) and EC GPP (79.6 days, padj < 0.0001). Landscape heterogeneity did not explain differences in SOS and EOS estimates. Annual integrated estimates of productivity from EC GPP and PhenoCam GCC diverged from those estimated by Landsat GPP and NDVI at sites where annual production exceeds 1000 gC/m-2 yr-1. Based on our results, we developed a {\textquotedblleft}metric assessment framework{\textquotedblright} that articulates where and how metrics from satellite, eddy covariance and PhenoCams complement, diverge from, or are redundant with one another. The framework was designed to optimize instrumentation selection for monitoring, modeling, and forecasting ecosystem functioning with the ultimate goal of informing decision-making by land managers, policy-makers, and industry leaders working at multiple scales.}, keywords = {Agricultural management, eddy covariance, GPP, Growing season length, indicators, LandsatPhenoCam, Long-Term Agroecosystem Research (LTAR) network, Sustainable agriculture}, doi = {10.1016/j.ecolind.2021.108147}, url = {files/bibliography/21-031.pdf}, author = {Dawn M. Browning and Eric S. Russell and Guillermo E. Ponce-Campos and N. E. Kaplan and Andrew D. Richardson and Bijan Seyednasrollah and S. Spiegal and Nicanor Z. Saliendra and Joseph G. Alfieri and J. M. Baker and Carl Bernacchi and Brandon T Bestelmeyer and David D. Bosch and Elizabeth H. Boughton and Raoul K. Boughton and Patrick E. Clark and Gerald N. Flerchinger and Nuria Gomez-Casanovas and Sarah Goslee and Nick Haddad and David L. Hoover and Abdullah Jaradat and Marguerite Mauritz and Gregory McCarty and Gretchen R. Miller and John Sadler and Amartya Saha and R.L. Scott and Andrew Suyker and Craig Tweedie and Jeffrey D. Wood and Xukai Zhang and Shawn D. Taylor} } @article {JRN55334, title = {Making research relevant: Sharing climate change research with rangeland advisors to transform results into drought resilience}, journal = {Rangelands}, volume = {RALA-00311}, year = {2021}, month = {10/1/2021}, pages = {1-9}, abstract = {On the Ground {\textbullet}Public programs, strategies, and incentives to implement rangeland climate adaptation are more effective if they are tailored to local drought exposures, sensitivities, and adaptation opportunities. As such, local rangeland advisers who aid in climate adaptation are pivotal to the development of these resources. {\textbullet} We hosted a virtual workshop with rangeland advisors to share results from our climate vulnerability assessment, gain their insight on finding usability, and discuss visions for resource creation. {\textbullet}Climate adaptation resources should not follow a one-size-fits-all approach. Accommodating variety in resource development and outreach must consider multiple factors: variation in the ranching community, instability in the environment beyond climate, and rancher/manager identified variables in climate vulnerability assessment analyses.}, keywords = {climate change, co-ideation, engagement, rangelands, workshop}, doi = {10.1016/j.rala.2021.08.004}, url = {files/bibliography/21-046.pdf}, author = {Maude Dinan and Peter B. Adler and James A. Bradford and M. Brunson and Emile H. Elias and Andrew Felton and Christina Greene and J. James and Katharine N. Suding and Eric Thacker} } @article {JRN55327, title = {Mobile phone use and agricultural productivity among female smallholder farmers in Tanzania}, journal = {Agri-gender}, volume = {6}, year = {2021}, month = {9/15/2021}, pages = { 43-54}, abstract = {Evidence shows that mobile phones can improve agricultural productivity in Sub-Saharan Africa, yet few studies examine gender disparities in mobile phone ownership and use, and how they relate to the gender gap in agricultural productivity. This research gathers survey data on 279 male and female household heads in four villages in Iringa, Tanzania, and investigates the associations between gender, agricultural productivity, and phone ownership and use. Our study finds that many farmers use phones to conduct agricultural activities, with virtually all male respondents using their privately-owned phones compared to only two-thirds of female respondents. Moreover, many women have positive perceptions and trust in the benefits of using phones for agricultural activities. Lastly, phone owners have higher self-reported maize yields compared to non{\textendash}phone owners. Our results suggest that mobile phones may be a valuable tool in bridging the agricultural gender gap.}, keywords = {Africa, agriculture, Gender, mobile phones, Tanzania, Women}, doi = {10.19268/JGAFS.612021.4}, url = {files/bibliography/21-037.pdf}, author = {Amy Quandt and Jonathan Salerno and Timothy D. Baird and J. Terrence McCabe and Emilie Xu and Jeffrey E. Herrick and Joel Hartter} } @article {JRN55277, title = {Multi-scale assessment of a grassland productivity model}, journal = {Biogeosciences}, volume = {18}, year = {2021}, month = {04/2021}, pages = {2213-2220}, chapter = {2213}, abstract = {Grasslands provide many important ecosystem services globally and forecasting grassland productivity in the coming decades will provide valuable information to land managers. Productivity models can be well-calibrated at local scales, but generally have some maximum spatial extent in which they perform well. Here we evaluate a grassland productivity model to find the optimal spatial extent for parameterization, and thus for subsequently applying it in future forecasts for North America. We also evaluated the model on new vegetation types to ascertain its potential generality. We find the model most suitable when incorporating only grasslands, as opposed to also including agriculture and shrublands, and only in the Great Plains and Eastern Temperate Forest ecoregions of North America. The model was not well suited to grasslands in North American Deserts or Northwest Forest ecoregions. It also performed poorly in agriculture vegetation, likely due to management activities, and shrubland vegetation, likely because the model lacks representation of deep water pools. This work allows us to perform long-term forecasts in areas where model performance has been verified, with gaps filled in by future modelling efforts.}, doi = {https://doi.org/10.5194/bg-18-2213-2021}, url = {files/bibliography/21-010.pdf}, author = {Shawn D. Taylor and Dawn M. Browning} } @proceedings {JRN55188, title = {Monitoring plant community change at the Jornada Experimental Range: 100 Years of quadrat sampling}, volume = {$\#$92}, year = {2020}, month = {02/16/2020}, address = {Denver, CO}, abstract = {

The importance of long-term observational data sets as records of ecosystem responses to climatic variation and directional change continues to increase. Ecologists and land managers use such records to ask questions about how ecosystems responded to past climatic variation and perturbations, in order to understand mechanisms behind increase/decline of species of interest, and to inform predictions about future scenarios.

Sampling using chart quadrats was a common method in the early 20th century as a means to track availability of perennial grasses and other species as forage for liveestock.\  At the Jomada Experimental Range in southern New Mexico, chart quadrat sampling began in 1915 and continues through the present, with permanent quadrat locations being resampled approximately every 5 years. Using this detailed record we can not only investigate trends in grass cover, but also track variation in other plant community properties (e.g. species richness, species tumover, abundance distributions) as the system experienced severe droughts, variation in quantity and timing of yearly precipitation, and an overall trend of shrub encroachment\  over the past 100 \ years.

Like many desert rangelands in the southwest, cover of perennial grasses such as black grama (Bouteloua eriopoda) has declined dramatically since the early 1900s. In recent samples, there is some evidence that cover of B. eriopoda has increased slightly on the quadrats where it has remained, likely the result of new recruits rather than existing individuals increasing in size. We also found that while species richness has remained fairly constant during the past 20 years, rates of tumover were also high, with rates of 50\% tumover on average during each 5-year sampling interval. These results contribute to the broader picture of ecosystem dynamics at the Jomada Experimental Range, and demonstrate the value of long-term consistent sampling initiatives.

}, keywords = {community change, Jornada Experimental Range, monitoring, plant, quadrat sampling}, author = {Erica M. Christensen and Brandon T Bestelmeyer and Connie J. Maxwell and A. L. Slaughter and D. K. James and Kirsten B. Romig and Kris Havstad} } @inbook {JRN55305, title = {Managing animal manure to minimize phosphorus losses from land to water}, booktitle = {Animal Manure: Production, Characteristics, Environmental Concerns, and Management}, volume = {67}, year = {2020}, abstract = {Given the expansion of eutrophication in water bodies around the world, the improved management of manure to mitigate P losses to water has become a global concern. This chapter seeks to frame manure management strategies and practices to minimize P losses to water, with a focus on manure properties, land application, farmstead infrastructure, farming systems. Although many options exist to better manage manure, and, more specifically, P in manure, doing so requires comprehensive approaches that consider factors far beyond the direct handling of manure and require decisions that may compete or conflict with other priorities, most notably profits and time management.}, keywords = {estuarine waterbodies, farmstead infrastructure, in-field stacking, managing animal manure, manure application rate, manure phosphorus losses, phosphorus pollution}, doi = {10.2134/asaspecpub67.c12}, url = {files/bibliography/20-039.pdf}, author = {Peter J. A. Kleinman and S. Spiegal and Liu, Jian and Holly, Michael A. and C. Church and Ramirez-Avila, J.} } @article {JRN55209, title = {Management strategies for reducing the risk of equines contracting Vesicular Stomatitis Virus (VSV) in the Western United States}, journal = {Journal of Equine Veterinary Science}, year = {2020}, month = {05/2020}, chapter = {103026}, abstract = {Vesicular stomatitis viruses (VSV) cause a condition known as vesicular stomatitis (VS), which results in painful lesions in equines, cattle, swine, and camelids, and when transmitted to humans can cause flu-like symptoms. When animal premises are affected by VS, they are subject to a quarantine. The equine industry more broadly may incur economic losses due to interruptions of animal trade and transportation to shows, competitions, and other events. Equine owners, barn managers, and veterinarians can take proactive measures to reduce the risk of horses contracting VS. To identify appropriate risk management strategies, it helps to understand which biting insects are capable of transmitting the virus to animals, and to identify these insect vectors{\textquoteright} preferred habitats and behaviors. We make this area of science more accessible to equine owners, barn managers, and veterinarians, by: (1) translating the most relevant scientific information about biting insect vectors of VSV, and (2) identifying practical management strategies that might reduce the risk of equines contracting VSV from infectious biting insects or from other equines already infected with VSV. We address transmission risk at four different spatial scales{\textemdash}the animal, the barn/shelter, the barnyard/premises, and the surrounding environment/neighborhood{\textemdash}noting that a multi-scale and spatially collaborative strategy may be needed to reduce the risk of VS.}, keywords = {Biting midges, Black flies, Horse, Sand flies, Vector-borne disease}, doi = {https://doi.org/10.1016/j.jevs.2020.103026}, url = {files/bibliography/20-017.pdf}, author = {Dannele E. Peck and Reeves, Will K and Angela Pelzel-McCluskey and J. D. Derner and Barbara Drolet and Lee W Cohnstaedt and Dustin A Swanson and David McVey and Luis L Rodriguez and Debra C. Peters} } @article {JRN55290, title = {Modifying connectivity to promote state change reversal: the importance of geomorphic context and plant{\textendash}soil feedbacks}, journal = {Ecology}, volume = {101}, year = {2020}, month = {4/16/2020}, pages = {e03069}, abstract = {Alternative states maintained by feedbacks are notoriously difficult, if not impossible, to reverse. Although positive interactions that modify soil conditions may have the greatest potential to alter self-reinforcing feedbacks, the conditions leading to these state change reversals have not been resolved. In a 9-yr study, we modified horizontal connectivity of resources by wind or water on different geomorphic surfaces in an attempt to alter plant{\textendash}soil feedbacks and shift woody-plant-dominated states back toward perennial grass dominance. Modifying connectivity resulted in an increase in litter cover regardless of the vector of transport (wind, water) followed by an increase in perennial grass cover 2 yr later. Modifying connectivity was most effective on sandy soils where wind is the dominant vector, and least effective on gravelly soils on stable surfaces with low sediment movement by water. We found that grass cover was related to precipitation in the first 5 yr of our study, and plant{\textendash}soil feedbacks developed following 6 yr of modified connectivity to overwhelm effects of precipitation on sandy, wind-blown soils. These feedbacks persisted through time under variable annual rainfall. On alluvial soils, either plant{\textendash}soil feedbacks developed after 7 yr that were not persistent (active soils) or did not develop (stable soils). This novel approach has application to drylands globally where desertified lands have suffered losses in ecosystem services, and to other ecosystems where connectivity-mediated feedbacks modified at fine scales can be expected to impact plant recovery and state change reversals at larger scales, in particular for wind-impacted sites.}, keywords = {aeolian processes, alternative states, cusp-catastrophe model, desertification, ecohydrology, long-term studies, regime shifts remediation}, doi = {10.1002/ecy.3069}, url = {files/bibliography/20-035.pdf}, author = {Debra C. Peters and Gregory S. Okin and Jeffrey E. Herrick and Heather Savoy and John P. Anderson and Stacey L P Scroggs and J. Zhang} } @article {JRN55294, title = {Mobile phone use is associated with higher smallholder agricultural productivity in Tanzania, East Africa}, journal = {PLoS ONE}, volume = {15}, year = {2020}, month = {August 6, 2020}, pages = {e0237337}, abstract = {Mobile phone use is increasing in Sub-Saharan Africa, spurring a growing focus on mobile phones as tools to increase agricultural yields and incomes on smallholder farms. However, the research to date on this topic is mixed, with studies finding both positive and neutral associations between phones and yields. In this paper we examine perceptions about the impacts of mobile phones on agricultural productivity, and the relationships between mobile phone use and agricultural yield. We do so by fitting multilevel statistical models to data from farmer-phone owners (n = 179) in 4 rural communities in Tanzania, controlling for site and demographic factors. Results show a positive association between mobile phone use for agricultural activities and reported maize yields. Further, many farmers report that mobile phone use increases agricultural profits (67\% of respondents) and decreases the costs (50\%) and time investments (47\%) of farming. Our findings suggest that there are opportunities to target policy interventions at increasing phone use for agricultural activities in ways that facilitate access to timely, actionable information to support farmer decision making.}, keywords = {agricultural workers, agriculture, cell phones, cereal crops, farms, maize, surveys, Tanzania}, doi = {10.1371/journal.pone.0237337}, url = {files/bibliography/20-036.pdf}, author = {Amy Quandt and Jonathan Salerno and J. Neff and Timothy D. Baird and Jeffrey E. Herrick and J. Terrence McCabe and Emilie Xu and Joel Hartter} } @article {JRN55264, title = {Manureshed delineation via analysis of county-level data from IPNI-NuGIS and USDA-NASS(2012)}, year = {2020}, abstract = {Nutrient recycling is fundamental to sustainable agricultural systems, but few mechanisms exist to ensure that surplus manure nutrients from animal feeding operations are transported for use on nutrient-deficient croplands. As a result, manure nutrients concentrate in locations where they can threaten environmental health and devalue manure as a fertilizer resource. This data set is from a study advances the concept of the {\textquotedblleft}manureshed{\textquotedblright} {\textendash} the lands surrounding animal feeding operations onto which manure nutrients can be redistributed to meet environmental, production, and economic goals. Manuresheds can be managed at multiple scales, for example, on farms with both animals and crops, among animal farms and crop farms within a county, or even among animal farms and crop farms in distant counties. With a focus on redistribution among counties, we classified the 3109 counties of the contiguous United States by their capacity to either supply manure phosphorus (P) and nitrogen (N) from confined livestock production ({\textquotedblleft}sources{\textquotedblright}) or to assimilate and remove excess P and N via crops ({\textquotedblleft}sinks{\textquotedblright}) [see data for N tonnes, P tonnes, N kg/ha, P kg/ha]. Manure nutrient source counties were identified in 40 of the 48 states, with a substantial concentration in the southern US. Source counties for manure P greatly outnumbered source counties for manure N (390 vs. 100), and 99 of the 100 manure N source counties were also source counties for manure P. Conversely, sink counties for manure N outnumbered sink counties for manure P (2766 vs. 2317). We used the P balances of the source and sink counties to delineate four manuresheds dominated by various combinations of confined hog, poultry, dairy, and beef industries [see data for Manuresheds (tonnes)]. The four manuresheds differed in the transport distances needed to assimilate excess manure P from their respective source areas (from 147 {\textpm} 51 km for a beef dominated manureshed to 368 {\textpm} 140 km for a poultry dominated manureshed), highlighting the need for systems-level strategies to promote manure nutrient recycling that operate across local, county, regional, and national scales.}, keywords = {Agrosystems \& Environment, Animals \& Livestock, Biogeeochemistry, GIS Data and Images, Land cover/use, management, Maps \& Multimedia, nutrients, Organic Matt, Plants \& Crops, soil}, doi = {https://doi.org/10.15482/USDA.ADC/1518435}, author = {S. Spiegal and Peter J. A. Kleinman and Dinku Endale and Ray Bryant and Curtis Dell and Sarah Goslee and Meinen, Robert J and Colton K Flynn and J. M. Baker and Dawn M. Browning and Gregory McCarty and S. Bittman and Jennifer Carter and Michael Cavigelli and Emily Duncan and Prasanna Gowda and Xia Li and G.E. Ponce and Raj, Cibin and Maria Silveira and Douglas Smith and Dan Arthur and Yang, Qichun and Nezat, Caryn and Bruce Vandenberg} } @article {JRN55208, title = {Manuresheds: Advancing nutrient recycling in US agriculture}, journal = {Agricultural Systems}, volume = {182}, year = {2020}, month = {05/2020}, chapter = {102813}, abstract = {Nutrient recycling is fundamental to sustainable agricultural systems, but few mechanisms exist to ensure that surplus manure nutrients from confined animal feeding operations are transported for use in nutrient-deficient croplands. As a result, surplus manure nutrients concentrate in locations where they can threaten environmental health and devalue manure as a fertilizer resource. This study advances the concept of the {\textquotedblleft}manureshed{\textquotedblright} {\textendash} the lands surrounding animal production operations where manure nutrients can be redistributed to meet environmental, production and economic goals. Manuresheds can be managed at multiple scales, for example, on farms with both animals and crops where manure is applied to the farm{\textquoteright}{\textquoteright}s croplands, among animal farms and crop farms within a county, or even among animal and crop farms in neighboring or distant counties. With a focus on redistribution among counties, we classified the 3109 counties of the contiguous United States by their capacity to either supply manure phosphorus (P) and nitrogen (N) from confined livestock production ({\textquotedblleft}sources{\textquotedblright}) or to assimilate and remove excess P and N via crops ({\textquotedblleft}sinks{\textquotedblright}). Manure nutrient source counties were identified in 40 of the 48 states, with a substantial concentration in southern states. Source counties of manure P greatly outnumbered source counties of manure N (390 vs. 100), and all but one manure N source counties were also manure P source counties. Conversely, sink counties for manure N (2766 counties) outnumbered sink counties for manure P (2317 counties). We used the P balances of the source and sink counties to delineate four manuresheds with source areas dominated by various combinations of confined hog, poultry, dairy, and beef industries. The four manuresheds differed in the transport distances needed to assimilate excess manure P from their respective source areas (from 147 {\textpm} 51 km for a beef dominated manureshed to 368 {\textpm} 140 km for a poultry dominated manureshed), highlighting the need for systems-level strategies to promote manure nutrient recycling that operate across local, county, regional and national scales. }, keywords = {Livestock manure, Long-Term Agroecosystem Research (LTAR) network, nitrogen, nutrients, phosphorus}, doi = {https://doi.org/10.1016/j.agsy.2020.102813}, url = {files/bibliography/20-016.pdf}, author = {S. Spiegal and Peter J. A. Kleinman and Dinku Endale and Ray Bryant and Curtis Dell and Sarah Goslee and Meinen, Robert J and Colton K Flynn and J. M. Baker and Dawn M. Browning and Gregory McCarty and S. Bittman and Jennifer Carter and Michael Cavigelli and Emily Duncan and Prasanna Gowda and Xia Li and G.E. Ponce and Raj, Cibin and Maria Silveira and Douglas Smith and Dan Arthur and Yang, Qichun} } @conference {JRN54993, title = {Movement and Cow-calf proximity patterns of Raramuri Criollo vs. Angus-crossbred nursing cows grazing Chihuahuan Desert rangeland in summer}, 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 = {

The objective of this study was to compare cow-calf proximity patterns of nursing Angus X Hereford (AH) and Raramuri Criollo (RC) cows in large Chihuahuan Desert pastures during the summers of 2016 and 2017. Eleven cow-calf pairs of each breed grazed two adjacent pastures (1190ha, 1165ha) separately in a crossover design, for 4 weeks per deployment. Within each breed, a group of randomly selected cows were fitted with GPS collars which recorded animal position at 10-min intervals. Proximity loggers configured to record number and duration of contact events (\< 1m distance) were also fitted on a subset of cow-calf pairs. All calves were \<2 weeks old at the onset of the study. Data from the dam{\textquoteright}s proximity loggers were used for analysis. The effect of breed (AH vs. RC) on duration and number of contact events, as well as distance traveled, path sinuosity, velocity, area explored, and time spent resting, grazing and traveling by the dams was determined via ANOVA. All variables were calculated for four daily periods: Midnight to Sunrise (AmNight); Sunrise to Noon (AmDay); Noon to Sunset (PmDay); and Sunset to Midnight (PmNight). Breed (Pasture*year) was treated as the experimental unit and differences were declared significant at P = 0.05.\  Number and duration of cow-calf contacts was highest during PmDay and lowest during AmNight and no breed-related differences were observed. RC cows traveled farther at higher velocities during AmNight, AmDay and PmDay and explored an area almost three times larger than the area explored by AH counterparts (152 vs. 57 ha). RC cows spent more time traveling during AmNight, AmDay and PmDay, more time grazing during AmNight and PmDay and less time resting during AmNight and PmDay than their AH counterparts. Our data suggest that RC calves impose fewer constraints on their dams{\textquoteright} grazing patterns compared to commonly-used British crossbreds when grazing the Chihuahuan Desert during summer.

}, author = {S. Nyamuryekung{\textquoteright}e and Andr{\'e}s F. Cibils and Richard E. Estell and Amy L. Gonzalez and Matthew M. McIntosh and S. Spiegal and F. G. Continanza} } @conference {JRN55163, title = {Mobile phone app for gardeners to access soil survey information}, booktitle = {Social Sciences}, volume = {PL-60}, year = {2019}, month = {06/10/2019}, abstract = {

Soil resource information can help gardeners better understand what is possible to grow on their land, and how they could improve it. However, the delivery of soil survey interpretations to the end-user is often complicated by soil map unit complexity where multiple classes are contained within a map unit and the subsequent human modification of these soil classes into urban lawns or gardens. Even in areas where human development has expanded into previously mapped areas, soils have been so modified that soil maps no longer provide correct information of soil resources. The Land Potential Knowledge System (LandPKS) is a modular mobile phone app developed to connect farmers, gardeners, and other land managers to US and global soil survey information based on location and user inputs. It is available free on the Google Play and iPhone App stores. LandPKS recently implemented a soil identification (SoilID) algorithm to match smartphone-based user data acquisition (e.g., GPS location, soil texture, and color by depth) through cloud-based computing to return soil component matching for any given point. While this approach has proven to reliably deliver soil class information to the user, it is ultimately limited to available soil concepts for that area{\textquoteright}s soil survey. Our presentation will describe recent advances from the LandPKS app related to identifying these modified soil resources. We will also demonstrate other LandPKS modules that allow users to plan and record management inputs and activities, and document changes in soil health.

}, author = {S. W. Salley and Jeffrey E. Herrick and Jonathan Maynard} } @conference {JRN55048, title = {Manuresheds: Redesigning crop-livestock agriculture for sustainable intensification}, booktitle = {2019 Annual Meeting of the US Regional Association of the ​International Association for Landscape Ecology}, year = {2019}, month = {04/2019}, address = {Fort Collins, CO}, abstract = {

Meeting the dietary demands of humans while protecting Earth{\textquoteright}s ecosystems is among the greatest challenges of the Anthropocene. Sustainable intensification is expanding as a response to this grand challenge, but success will require an improved understanding of regional, national, and international agricultural systems, including spatial relationships among system components, land use changes that influence the spatial relationships, and optimal approaches to distributing resources. Agricultural specialization and intensification of the 19th and 20th centuries are central considerations, as these advancements led to monumental increases in production and efficiency, but also resulted in uneven geographic distribution of agriculture types and an uncoupling of nutrient biogeochemical cycles. Now, concentrations of animals in certain regions produce manure nutrient accumulations that contribute to air and water pollution, while concentrations of crops in other regions result in nutrient deficits typically filled by intensive fertilizer use. Great potential exists to create new nutrient cycles through strategic consideration of manure sources and crop requirements. This recoupling requires creative solutions. To that end, the Long-Term Agroecosystem Research (LTAR) network is exploring the concept of the {\textquotedblleft}manureshed,{\textquotedblright} the manure-spreadable land in the geographic, environmental, and social radius of a confined livestock operation. To better understand opportunities for expanding manuresheds in the United States, we identified the nationwide, county-level pattern of livestock distribution, manure excess, and crop assimilation of manure nutrients. Manure phosphorus and nitrogen leftover after crop removal were calculated assuming all manure produced in the county was applied to all croplands in the county. We then classified counties with manure in excess of cropland assimilative capacity into types distinguished by barriers to, and possibilities for, expanding manuresheds within and between counties. We expect that manureshed research can guide the redesign of crop-livestock agriculture to advance sustainable intensification in the United States and other nations.

}, author = {S. Spiegal and Peter J. A. Kleinman and Ray Bryant and Dinku Endale and Curtis Dell and Yang, Qichun and Colton K Flynn and Prasanna Gowda and Emily Duncan and Jennifer Carter and Dawn M. Browning} } @article {JRN54903, title = {Make a difference: ecology careers in federal agencies}, journal = {Frontiers in Ecology and the Environment}, year = {2018}, month = {01 August 2018}, doi = {https://doi.org/10.1002/fee.1926}, author = {Mari-Vaughn V. Johnson and J Strickland and Jeffrey E. Herrick} } @proceedings {JRN54868, title = {Mother-Offspring Interactions in Raramuri Criollo Cattle on New Mexico and Chihuahua (Mexico) Rangelands}, volume = {January 28-February 2, 2018}, year = {2018}, month = {01/28/2018}, publisher = {Society for Range Management Meeting Proceedings}, address = {Sparks, Nevada}, abstract = {

Rangeland beef cows spend approximately six months of a typical year raising their calf. This endeavor is known to significantly alter a dam{\textquoteright}s grazing behavior and spatial distribution patterns. The objective of this study was to characterize cow-calf contact events in two herds of Raramuri Criollo (RC) cattle that grazed rangeland pastures in southern New Mexico (NM, 4355 ha) and west-central Chihuahua, Mexico (623 ha). At each site, five to nine randomly selected mature nursing cows were fitted with Lotek 3300LR GPS collars and Sirtrak proximity loggers. GPS collars recorded animal position at 5-min intervals, whereas proximity loggers recorded initiation time and duration of mother-offspring contact events (\<3m distance). All calves were \<2 weeks old at the onset of the study. Collared animals grazed with a herd of 30 and 35 cows at the NM site and with 68 and 87 cows at the Chihuahua site in 2015 and 2016, respectively. We computed number of contact events and duration of each event for 24h time periods, and for daytime and nighttime hours. ANOVA was used to determine if contact events and duration of each event changed as a function of calf age or time of day (day vs. nighttime). We also determined whether daily area explored by a cow and its calf differed. Day vs. nighttime mother-offspring contact events and contact time were not different (P=0.05). Dams explored larger areas of the pasture than did their calves on any given day (40.3 vs. 29.2 ha; P= 0.0249). Cow-calf interactions tended to decrease and mother-offspring difference in daily area explored tended to increase as calves became older. Our results suggest that RC calves follow their dams during daily grazing bouts and are likely to constrain their dams{\textquoteright} feeding site selection the most during the first weeks after calving.

}, author = {S. Nyamuryekung{\textquoteright}e and Andr{\'e}s F. Cibils and Richard E. Estell and Amy L. Gonzalez and Roacho-Estrada, J.O. and Rodriguez-Almedia, F. A. and S. Spiegal} } @conference {JRN54935, title = {A machine learning guided system for automatically processing data from an array of wireless sensors}, booktitle = {International Conference on Complex Systems}, year = {2018}, month = {07/2018}, address = {Cambridge, Massachusettes}, abstract = {

We present a system that automatically processes data from an array of remote sensors in a wireless network and makes these data available online. Our system automatically performs QA/QC using the GCE LTER Data toolbox for Matlab. Additionally, the GCE toolbox help us to manage metadata and data in multiple formats. Users can explore data with tools to graph, select stations, variables, and time. We have connected this QA/QC process with our Knowledge, Learning, and Analysis System (KLAS) to allow users to perform experiments with the data collected. KLAS can learn from users{\textquoteright} behavior using machine learning to serve as a guide during the process of approving provisional data and during the experimentation process by making recommendations. KLAS can help the scientific community to reuse data, methods, and models.

}, author = {Geovany Ramirez and Debra C. Peters and John P. Anderson} } @conference {JRN55062, title = {A more or less dusty future?}, booktitle = {Ecological Society of America Meeting}, year = {2018}, month = {08/2018}, address = {New Orleans, Louisiana}, abstract = {

Wind erosion and blowing dust impact air quality, biogeochemical cycles, the hydrologic cycle and climate, and are major resource concerns for land managers; but where is all the dust coming from, and why? Will there be more, or less, dust in the future? How we will answer these questions presents numerous research challenges with consequences for human health, ecosystem services, and how we prepare agriculture to meet food and fiber demands under a changing climate. I will explore these challenges and identify opportunities for new interdisciplinary research to tackle them.

}, author = {Nicholas Webb} } @proceedings {JRN54862, title = {Multi-scale wind erosion monitoring and assessment for US rangelands}, volume = {January 28-February 2, 2018}, year = {2018}, month = {01/28/2018}, publisher = {Society for Range Management Meeting Proceedings}, address = {Reno, NV}, abstract = {

Wind erosion is a major resource concern for rangeland managers. Although wind erosion is a naturally occurring process in many drylands, land use activities, and land management in particular, can accelerate wind-driven soil loss {\textendash} impacting ecosystem dynamics and agricultural production, air quality, human health, biogeochemical cycles, and climate. Wind erosion has large variability in space and time, and as a consequence is difficult to monitor effectively in ways that can support its management. Existing US air quality monitoring programs provide indicators of wind erosion intensity (e.g., particulate matter [PM] concentrations) and associated benchmarks (e.g., Clean Air Act) are regulated federally but provide no information about which landscapes are eroding, but how much, or when. Standardized rangeland monitoring programs like the BLM{\textquoteright}s Assessment, Inventory and Monitoring (AIM) Strategy and the NRCS{\textquoteright}s National Resources Inventory (NRI) collect information about soil properties (texture) and vegetation (foliar cover, canopy gap size, height) that, coupled with remote sensing products and numerical models, can be used to estimate wind erosion and dust emission rates across spatial scales to better inform management. Here I present an overview of the National Wind Erosion Research Network and ongoing efforts to develop decision-support tools that connect existing soil, vegetation and air quality monitoring programs to provide information to federal agencies and the public about wind erosion rates. I demonstrate how core indicators used in the AIM and NRI monitoring programs can be integrated to assess dust emission rates; enabling air quality, human health and ecosystem impacts of dust to be linked to changes in range condition and benchmarks for rangeland management. I then describe how AIM and NRI data can be used to interpret remote sensing-driven model estimates of wind erosion and understand interactions with land use and management activities across ecological sites.

}, author = {Nicholas Webb} } @article {JRN55183, title = {Measurement of Soil Color: A Comparison Between Smartphone Camera and the Munsell Color Charts}, journal = {Soil Science Society of America Journal}, volume = {81}, year = {2017}, month = {September 7 2017}, pages = {1139-1146}, abstract = {

Soil color is one of the most useful soil properties for assessing and monitoring soil health. Here we present results of tests of a new soil color app for mobile phones. Various smartphone cameras (SPCs) were tested under sunny and cloudy conditions and compared with visual estimates using Munsell color charts (MCCs). The measured and estimated soil colors were then compared with the {\textquotedblleft}true{\textquotedblright} colors determined using a spectrophotometer. The results indicated that soil color determinations based on SPC measurements under both sunny and cloudy conditions were as good as those obtained using the MCCs. The accuracy of the SPC measurements was affected by the natural illumination conditions, with higher accuracy in the sun than where clouds were present. Our results also indicated that the SPC measurements completed in the sun provide higher precision (lower variance) than SPC measurements completed under cloudy conditions or estimates based on MCCs. These results suggest that mobile-device cameras have great potential to allow non{\textendash}soil scientists, and others lacking access to color charts, to determine soil color.

}, keywords = {CIE, International Commission on Illumination, MMC, Munsell color chart; sRGB, smartphone camera, SPC, standard red-green-blue color space}, doi = {10.2136/sssaj2017.01.0009 }, url = {files/bibliography/17-036.pdf}, author = {Zhoasheng Fan and Jeffrey E. Herrick and R. Saltzman and Christina Matteis and Anna Yudina and Nicholas Nocella and Edward Crawford and Rick Parker and Justin Van Zee} } @inbook {JRN54700, title = {Monitoring protocols: Options, approaches, implementation, benefits}, booktitle = {Rangeland Systems}, year = {2017}, pages = {527-567}, publisher = {Springer}, organization = {Springer}, chapter = {16}, address = {Gewerbestrasee, Switzerland}, abstract = {
Monitoring and adaptive management are fundamental concepts to rangeland management across land management agencies and embodied as best management practices for private landowners. Historically, rangeland monitoring was limited to determining impacts or maximizing the potential of specific land uses {\textendash} typically grazing. Over the past several decades, though, the uses of and disturbances to rangelands have increased dramatically against a backdrop of global climate change that adds uncertainty to predictions of future rangeland conditions. While the multi-dimensional monitoring needs for rangeland management must be reconciled with the harsh realities of the costs to collect the requisite data, conceptual advances in rangeland ecology and management over the past 25 years, driven by developments in ecological theory, and changes in natural resource policies and societal values have facilitated new approaches to monitoring that can support rangeland management{\textquoteright}s diverse information needs. Additionally, advances in sensor technologies and remote-sensing techniques have broadened the suite of rangeland attributes that can be monitored and the temporal and spatial scales at which they can be monitored. We review some of the conceptual and technological advancements over the past 25 years and provide examples of how they have influenced rangeland monitoring. We then discuss implications of these developments for rangeland management and highlight what we see as challenges and opportunities for implementing effective rangeland monitoring. We conclude with a vision for how monitoring can contribute to rangeland information needs in the future.
}, doi = {10.1007/978-3-319-46709-2_16}, url = {files/bibliography/17-012.pdf}, author = {Jason W. Karl and Jeffrey E. Herrick and D.A. Pyke} } @article {JRN54809, title = {Modified centroid for estimating sand, silt, and clay from soil texture class}, journal = {Soil Science Society of America Journal}, volume = {81}, year = {2017}, month = {06/2017}, pages = {578-588}, chapter = {578}, abstract = {

Models that require inputs of soil particle size commonly use soil texture class for input; however, texture classes do not represent the continuum of soil size fractions. Soil texture class and clay percentage are collected as a standard practice for many land management agencies (e.g., NRCS, BLM, FAO) and clay content is frequently estimated with acceptable accuracy ({\textpm}5\%). When clay and texture class is known, sand and silt can be constrained to a narrow range that may differ from the geometric centroid of a given texture class (gcent). I tested the concept of a modified centroid approach (mcent) using 75,736 soil samples from the National Cooperative Soil Survey pedon database that also had measured hydraulic soil properties. Comparisons were made using the Rosetta pedotransfer function (PTF) to test modeled values from gcent, mcent, and measured data in comparison to measured values of water content at field capacity ({\textquoteright}330) wilting point ({\textquoteright}15000,). The mcent approach produced a continuous distribution of values for sand and silt whereas gcent produced a stair-step pattern for each of the 12 texture classes. Rosetta underestimated water content. Unbiased root mean square error was smaller for mcent than gcent for seven and ten of the 12 soil texture classes for {\textquoteright}330 and {\textquoteright}15000, respectively. Results support the practice of collecting field estimates of clay percentage along with texture class to expand the use of soil profile data for both spatial and non-spatial modeling of soil processes that will advance our understanding of soil contributions to ecosystem function.

}, doi = {10.2136/sssaj2016.09.0301}, url = {files/bibliography/17-013.pdf}, author = {Matthew Levi} } @article {JRN54660, title = {Making soil health a part of rangeland management}, journal = {Journal of Soil and Water Conservation}, volume = {71:55A-60A}, year = {2016}, month = {04/2016}, abstract = {
Soil health describes the ability of a soil to function at its potential, specifically {\textquotedblleft}The capacity of a soil to function as a vital, living ecosystem that sustains plants, animals and humans{\textquotedblright}. The objectives of this paper are to 1) contextualize rangeland soil health by examining the common definition and how important concepts apply to rangelands, 2) review the recent progress and ongoing directions in applying soil and ecosystem health concepts to rangelands and 3) identify and better define opportunities to move soil health forward as an important part of rangeland management. Rangeland soil health assessment has a well-documented history and has continually improved (albeit sporadically) over the past 3 decades. \ We conclude, however, that these efforts need to expand to both new rangeland ecosystems and to new working groups. \ The existing approach to evaluation of rangeland soil health currently integrated into the Interpreting Indicators of Rangeland Health (IIRH) approach has been sufficiently tested to provide the most logical basis for future work. \ This protocol is closely linked to a standard set of quantitative measurements and indicators, including soil aggregate stability, that have been adopted for use by both the NRCS National Resource Inventory and by the BLM national Assessment, Inventory and Monitoring initiative. This is the most cost-effective means of gaining the necessary information to test and refine site-specific indicators. We conclude that continued testing, and refinement, of these 17 indicators, and the associated quantitative methods, guided by site-specific reference sheets offers the greatest probability of gaining a systematic understanding of rangeland soil health. This attempt to improve the systematic understanding of rangeland soil health also requires an increased emphasis on the development of a common database for soil, vegetation and soil attributes derived from conservation program and technical assistance applications to refine the use of this approach. \ 
}, doi = {10.2489/jswc.71.3.55A}, url = {files/bibliography/16-031.pdf}, author = {Joel R. Brown and Jeffrey E. Herrick} } @conference {JRN54642, title = {Monitoring protocols: options, approaches, implementation, benefits}, booktitle = {69th Annual Meeting of the Society for Range Management}, year = {2016}, month = {02/2016}, publisher = {Annual Meeting of the Society for Range Management}, organization = {Annual Meeting of the Society for Range Management}, address = {Corpus Christi, TX}, abstract = {
Monitoring and adaptive management are fundamental concepts to rangeland management across land management agencies and embodied as best management practices for private landowners. Historically, rangeland monitoring was limited to determining impacts or maximizing the potential of specific land uses {\textendash} typically grazing. Over the past several decades, though, the uses of and disturbances to rangelands have increased dramatically against a backdrop of global climate change that adds uncertainty to predictions of future rangeland conditions. Thus, today{\textquoteright}s monitoring needs are more complex (or multi-dimensional) and yet still must be reconciled with the realities of costs to collect requisite data. However, conceptual advances in rangeland ecology and management and changes in natural resource policies and societal values over the past 25 years have facilitated new approaches to monitoring that can support rangeland management{\textquoteright}s diverse information needs. Additionally, advances in sensor technologies and remote-sensing techniques have broadened the suite of rangeland attributes that can be monitored and the temporal and spatial scales at which they can be monitored. We review some of the conceptual and technological advancements and provide examples of how they have influenced rangeland monitoring. We then discuss implications of these developments for rangeland management and highlight what we see as challenges and opportunities for implementing effective rangeland monitoring. We conclude with a vision for how monitoring can contribute to rangeland information needs in the future.
}, author = {Jason W. Karl and Jeffrey E. Herrick and D.A. Pyke} } @conference {JRN54617, title = {Mesquite seed density in fecal samples of Raramuri Criollo vs. Angus x Hereford cows grazing Chihuahuan Desert Rangeland}, booktitle = {69th Annual Meeting of the Society for Range Management}, year = {2016}, month = {01/31/2016}, publisher = {Society of Range Management}, organization = {Society of Range Management}, address = {Corpus Christi, Texas}, abstract = {

This study was part of a larger project investigating breed-related differences in feeding habits of Raramuri Criollo (RC) versus Angus x Hereford (AH) cows. Seed densities in fecal samples collected in July and August 2015 were analyzed to compare presumed mesquite bean consumption of RC and AH cows grazing Chihuahuan Desert rangeland in summer. Two groups of 11 nursing RC or AH cows grazed separately in large adjacent pastures for four weeks. After the first two weeks, groups switched pastures to insure that both breeds were exposed to the same grazing environment. Five cows in each group were fitted with GPS collars configured to log animal location at 10 minute intervals. Weekly rectal fecal samples were collected from all 22 cows. Fecal samples were frozen and later thawed at 40oC. All seeds were recovered, surface sterilized, identified, counted, weighed, and placed in petri dishes at room temperature. Seedless thawed fecal samples were then dried at 60oC for 72 h and weighed. A mixed effects repeated measures analysis of variance was used to determine the influence of breed and pasture on mesquite seed density in fecal samples of RC and AH cows. \ Mesquite seed density in feces was significantly higher in RC vs. AH cows (Mean {\textpm} SEM RC: 0.21 {\textpm} 0.01 vs. AH: 0.09 {\textpm} 0.03 seeds/g seedless fecal DM; P = 0.03). Mesquite seed density in RC fecal samples was similar regardless of pasture grazed (P=0.32). Conversely, seed density for AH cows differed significantly among pastures (P = 0.03). Despite their apparent higher consumption of mesquite beans, GPS data revealed that RC spent detectably less time (P= 0.05) in mesquite-dominated plant communities than their AH counterparts. Our preliminary results suggest that during summer months, RC cows included higher amounts of mesquite seed pods in their diet compared to AH counterparts. The fact that AH cows spent more time than their RC counterparts in mesquite-dominated areas suggests that AH possibly seek mesquite shrubs for both forage and shade.

}, author = {Mercado, T.J. and Andr{\'e}s F. Cibils and S. Nyamuryekung{\textquoteright}e and Richard E. Estell and Amy L. Gonzalez} } @conference {JRN54632, title = {Movement and spatial proximity patterns of rangeland-raised Raramuri Criollo cow-calf pairs}, booktitle = {Journal of Animal Science Supplement}, year = {2016}, month = {07/2016}, publisher = {Journal of the Animal Science }, organization = {Journal of the Animal Science }, abstract = {
The objective of this study was to compare movement patterns of nursing vs. nonnursing mature cows and to characterize cow-calf proximity patterns in two herds of Raramuri Criollo cattle. Herds grazed rangeland pastures in southern New Mexico (4355 ha) and west-central Chihuahua, Mexico (633 ha){\textquoteright}{\textquoteright} At each site, five nursing and four nonnursing adult cows weighing approximately 325 kg were fitted with Lotek 3300 LR GPS collars which recorded animal position at 10-min intervals for 25 d during March to April 2015. Nursing cows and their calves were also fitted with Sirtrack proximity loggers that recorded number and length of dam-calf contact events (\<m distance). All calves were \<2 wk old at the onset of the study. Collared animals grazed with a herd of 30 and 68 adult cows at the NM and Chihuahua sites, respectively. Distance traveled and path sinuosity of cows and time spent by calves within 3 m of their dam and number of dam-calf contact events during day and nighttime hours were calculated. \ Movement data were subjected to ANOVA to determine effect of cow state (nursing vs. nonnursing) on distance traveled and path sinuosity. ANOVA was also used to determine if calves spent similar amounts of time within 3 m of their dam during day vs. nighttime hours. PROC MIXED (SAS 9.3) with a randomized complete block design was used for statistical analyses. No differences were detected in distance traveled by nursing and nonnursing cows over a 24-h period (8.43 vs. 8.56 {\textpm} 0.29 km; P = 0.67), daytime (5.47 km vs. 5.75 {\textpm} 0.24 km; P = 0.24), or nighttime hours (2.96 vs. 2.80 {\textpm} 0.15 km; P = 0.32). However, nighttime/daytime ratio of distance traveled was greater for nursing cows (0.62 vs. 0.55 {\textpm} 0.08; P = 0.05). \ Nursing cows exhibited more sinuous 24 h travel trajectories compared with nonnursing counterparts (0.13 vs. 0.18 {\textpm} 0.05 km; P \< 0.01). Calves spent on average 66.9 {\textpm} 3.41 min/d within 3 m of their dam, distributed over 86.4 {\textpm} 3.7 proximity events/d. Minutes spent by calves within 3 m of their dam were not different for day vs. nighttime periods (P = 0.07); however, more contact events occurred during daytime hours (predawn = 13.8; AM = 26.1; PM = 22.0; postsunset = 24.5 {\textpm} 2.02 contact events). Physiological state of Criollo cows affected their movement patterns in large rangeland pastures.
}, author = {S. Nyamuryekung{\textquoteright}e and Andr{\'e}s F. Cibils and Richard E. Estell and Amy L. Gonzalez and Roacho-Estrada, J.O. and Rodriguez-Almedia, F. A.} } @proceedings {JRN54572, title = {A method for testing land resource area concepts}, year = {2016}, month = {01/2016}, publisher = {Society for Range Management}, address = {Corpus Christi, TX}, abstract = {Land Resource Units (LRUs) are defined by the National Soil Survey Handbook as aggregations of soil map units and subunits of Major Land Resource Areas (MLRAs). In the USDA NRCS Land Resource Hierarchy, LRUs are defined as the level between MLRAs and STATSGO and are mapped at 1:1 million scale. They also function as an important framework for the development of Ecological Site (ES) concepts. While the art and science of resource area mapping has advanced significantly in the past several decades, NRCS LRU regionalizations have typically lacked suitable scientific foundations in defining resource area concepts. With the recently adopted Provisional Ecological Site initiative (intended to complete initial inventory of ES in the contiguous U.S. by 2020), a pressing need has risen to stratify ES concepts by a practical and functional LRA. Because resource areas, such as Major Land Resource Areas (MLRA), are rarely discrete physical entities{\textquoteright} often being conceptualizations reflecting perceived biases from the mapper{\textquoteright}it is important that resource areas implement rule-based procedures to test LRU concepts and geography. Here we present a methodology suitable for testing resource area boundary concepts and provide examples across the Continental U.S. }, author = {S. W. Salley and Curtis Talbot and Joel R. Brown} } @conference {JRN54448, title = {Multiscale ecosystem monitoring: an application of scaling data to answer multiple ecological questions}, booktitle = {68th Annual Society for Range Management Meeting}, year = {2015}, month = {02/2015}, publisher = {Sociiety for Range Management}, organization = {Sociiety for Range Management}, address = {Sacramento, CA}, abstract = {

Standardized monitoring data collection efforts using a probabilistic sample design, such as in the Bureau of Land Management{\textquoteright}s (BLM) Assessment, Inventory, and Monitoring (AIM) Strategy, provide a core suite of ecological indicators, maximize data collection efficiency, and promote reuse of monitoring datasets to address multiple ecosystem concerns at multiple scales. Our objective is to apply multi-scale monitoring data to answer questions related to overall landscape health, post-fire grazing closures, and emergency stabilization and rehabilitation (ES\&R) treatment effectiveness in northern California and northwestern Nevada. To meet this multi-scale objective, we deployed the AIM strategy at three spatial scales and intensities: low-intensity landscape sampling across the study area, medium-intensity sampling of the nine livestock grazing allotments which intersected the Rush Fire of 2012 (610,345 acres), and high-intensity sampling of ES\&R treatments within the fire boundary (2,558 acres). Terrestrial plots were established within a probabilistic sampling framework, and the BLM core indicators were measured at each plot (n=205) in 2013. At the landscape scale, indicator estimates varied with ecological potential, disturbance history, and land use. The sample points were then subset to answer management questions at local scales. ES\&R treatment effectiveness plots (n=28) were found to have high bare ground, low foliar cover, and low perennial plant density. When we applied the data (n=106) to answer post-fire livestock grazing monitoring questions, low perennial grass cover and high bare ground indicate insufficient recovery 1 year after the fire to support extensive livestock grazing. We also found that uncertainty increased with increased scale and decreased sampling density. This multi-scale monitoring approach maximizes efficiency in data collection, analysis, and reporting by acquiring the same ecological information at each scale and reusing data at each scale. This will enable land managers to efficiently and effectively collect monitoring data to inform decision making.

}, author = {Sarah McCord and D. K. James and Wilson, Dereck and Jason W. Karl and Emily Kachergis} } @article {JRN54189, title = {Modifying landscape connectivity by reducing wind driven sediment redistribution, northern Chihuahuan Desert, USA}, journal = {Aeolian Research}, volume = {17}, year = {2015}, month = {06/2015}, pages = {129-137}, chapter = {129}, abstract = {

Shrub encroachment into perennial grasslands is occurring in many arid parts of the world. As shrubs displace perennial grasslands, bare patches can coalesce creating sediment transport pathways that further enhance sediment fluxes by wind transport. Reducing the connectedness of these pathways could slow or stop grassland loss by limiting sediment redistribution. To test this hypothesis, sediment retention structures, hereafter called {\textquotedblleft}Connectivity Modifiers{\textquotedblright} (Con-Mods), were placed in bare gaps of existing shrublands to block sediment movement by wind transport on two sites: the basin floor and a bajada (i.e. piedmont slope) at the Jornada Basin LTER in southern New Mexico. Wind blown sediment collectors and short-lived radionuclides (210Pbex, 137Cs, and 7Be) were used to determine if these structures are affecting seasonal aeolian sediment transport within bare gaps. Net sediment flux rates at 10\ cm height indicate a loss of 2.5{\textendash}14.2\ g\ m-2\ d-1 for both sites for the monsoon season (Jul{\textendash}Nov), while the basin floor site was the most responsive in reducing sediment transport by collecting 16.5\ g\ m-2\ d-1 over the windy season (Dec{\textendash}May). Con-Mods contained 30{\textendash}50\% higher surface radionuclide activities than the control plots for both transport seasons on the basin floor. However, there was no detectible difference between surface concentrations for the structures and controls seasonally on the bajada site. This study demonstrates that changes in connectivity can influence sediment movement. Altering sediment transport through bare gaps could influence ecosystem state changes in arid systems; thereby increasing the likelihood of recruitment of native plants.

}, keywords = {aeolian transport, connectivity, desertification, sediment redistribution, short lived radionuclides, shrub encroachment}, doi = {10.1016/j.aeolia.2015.03.003}, url = {/files/bibliography/15-011.pdf}, author = {Rachal, David M. and Gregory S. Okin and Charles E. Alexander and Jeffrey E. Herrick and Debra C. Peters} } @article {JRN54213, title = {A multiscale, hierarchical model of pulse dynamics in arid-land ecosystems}, journal = {Annual Review of Ecology, Evolution and Systematics}, volume = {45}, year = {2014}, month = {09/01/2014}, pages = {397-419}, chapter = {397}, abstract = {

Ecological processes in aridlands are often described by the pulse-reserve paradigm where rain events drive biological activity until moisture is depleted leaving a reserve. This paradigm is frequently applied to processes stimulated by one or a few rainfall events within a growing season. Here we expand the original framework in time and space, and include other pulses that interact with rainfall.This new Hierarchical Pulse Dynamics Framework integrates space and time through pulse-driven exhanges, interactions, transitions, and transfers that occur across individual to multiple pulses extending from micro to watershed scales. Climate change will likely alter the size, frequency, and intensity of precipitation pulses in the future, and aridland ecosystems are known to be highly sensitive to climate variability. Thus, a more comprehensive understanding of aridland pulse dynamics will be needed to determine how these ecosystems will respond to, and be shaped by, increased climate variability.

}, keywords = {microbial processes, pulse-reserve paradigm, species interactions, state transitions}, doi = {10.1146/annurev-ecolsys-120213-091650}, url = {/files/bibliography/14-035.pdf}, author = {S.L. Collins and Jayne Belnap and N.B. Grimm and J.A. Rudgers and Dahm, C. and Paolo D{\textquoteright}Odorico and Litvak, M. and Natvig, D.O. and Debra C. Peters and Pockman, W.T. and Sinsabaugh, R. and Wolf, B.O.} } @article {JRN53961, title = {Modeling vegetation heights from high resolution stereo aerial photography: An application for broad-scale rangeland monitoring}, journal = {Journal of Environmental Management}, volume = {144}, year = {2014}, month = {06/2014}, pages = {226-235}, chapter = {226}, abstract = {

Vertical vegetation structure in rangeland ecosystems can be a valuable indicator for assessing rangeland health and monitoring riparian areas, post-fire recovery, available forage for livestock, and wildlife habitat. Federal land management agencies are directed to monitor and manage rangelands at landscapes scales, but traditional field methods for measuring vegetation heights are often too costly and time consuming to apply at these broad scales. Most emerging remote sensing techniques capable of measuring surface and vegetation height (e.g., LiDAR or synthetic aperture radar) are often too expensive, and require specialized sensors. An alternative remote sensing approach that is potentially more practical for managers is to measure vegetation heights from digital stereo aerial photographs. As aerial photography is already commonly used for rangeland monitoring, acquiring it in stereo enables threedimensional modeling and estimation of vegetation height. The purpose of this study was to test the feasibility and accuracy of estimating shrub heights from high-resolution (HR, 3-cm ground sampling distance) digital stereo-pair aerial images. Overlapping HR imagery was taken in March 2009 near Lake Mead, Nevada and 5-cm resolution digital surface models (DSMs) were created by photogrammetric methods (aerial triangulation, digital image matching) for twenty-six test plots. We compared the heights of individual shrubs and plot averages derived from the DSMs to field measurements. We found strong positive correlations between field and image measurements for several metrics. Individual shrub heights tended to be underestimated in the imagery, however, accuracy was higher for dense, compact shrubs compared with shrubs with thin branches. Plot averages of shrub height from DSMs were also strongly correlated to field measurements but consistently underestimated. Grasses and forbs were generally too small to be detected with the resolution of the DSMs. Estimates of vertical structure will be more accurate in plots having low herbaceous cover and high amounts of dense shrubs. Through the use of statistically derived correction factors or choosing field methods that better correlate with the imagery, vegetation heights from HR DSMs could be a valuable technique for broad-scale rangeland monitoring needs.

}, keywords = {Digital terrain model, photogrammetry, rangeland monitoring, remote sensing, Vegetation height}, doi = {10.1016/j.jenvman.2014.05.028}, url = {/files/bibliography/14-016.pdf}, author = {Jeffrey K. Gillan and Jason W. Karl and Danielle Duni and Ahmed Elaksher} } @article {JRN52693, title = {Mechanisms of grass response in grasslands and shrublands during dry or wet periods}, journal = {Oecologia}, volume = {174}, year = {2014}, pages = {1323-1334}, chapter = {1323}, abstract = {

Multi-year climatic periods are expected to increase with global change, yet long-term data are often insufficient to document factors leading to ecological responses. We used a suite of long-term datasets (1993-2010) to examine the processes underlying different relationships between aboveground net primary production (ANPP) and precipitation in wet and dry rainfall periods in shrublands and grasslands in the Chihuahuan Desert. We hypothesized that trends in ANPP can be explained by different processes associated with their dominant grasses [Bouteloua eriopoda (grasslands); Sporobolus flexuosus (shrublands)], and with ecosystem properties that influence soil water dynamics with feedbacks to ANPP. We compared datasets on recruitment and growth for seven years with no trend in precipitation followed by a four-year drought and five consecutive wet years. We integrated these data in a simulation model to examine the importance of positive feedbacks. In grasslands, ANPP was linearly related to precipitation regardless of rainfall period, primarily as a result of stolon recruitment by B. eriopoda. A lag in responses suggests the importance of legacies associated with stolon density. In shrublands, ANPP was only related to rainfall in the wet period when it increased nonlinearly as the number of wet years increased. Seed availability increased in the first year, and seedling establishment occurred two to four years later. Increases in biomass, litter, and simulated transpiration beginning in the third year corresponded with increases in ANPP. Understanding the processes underlying ecosystem dynamics in multi-year dry or wet periods is expected to improve predictions under directional increases or decreases in rainfall.

}, keywords = {Bouteloua eriopoda, Demographic processes, grasslands, Plant-soil water feedbacks, Sporobolu flexuosus}, doi = {10.1007/s00442-013-2837-y}, url = {/files/bibliography/14-004.pdf}, author = {Debra C. Peters and Jin Yao and Dawn M. Browning and A. Rango} } @article {JRN53985, title = {Modelling emergent patterns of dynamic desert ecosystems}, journal = {Ecological Monographs}, volume = {84}, year = {2014}, month = {08/2014}, pages = {373-410}, chapter = {373}, abstract = {

In many desert ecosystems vegetation is both patchy and dynamic: vegetated areas are interspersed with patches of bare ground, and both the positioning and the species composition of the vegetated areas exhibit change through time. These characteristics lead to the emergence of multi-scale patterns in vegetation that arise from complex relationships between plants, soils and transport processes. Previous attempts to probe the causes of spatial complexity and predict responses of desert ecosystems tend to be limited in their focus: models of dynamics have been developed with no consideration of the inherent patchiness in the vegetation, or else models have been developed to generate patterns with no consideration of the dynamics. Here we develop a general modelling framework for the analysis of ecosystem change in deserts that is rooted in the concept of connectivity and is derived from a detailed process-based understanding. We explicitly consider spatial interactions among multiple vegetation types and multiple resources, and our model is formulated to predict responses to a variety of endogenous and exogenous disturbances. The model is implemented in the deserts of the American Southwest both to test hypotheses of the causes of the invasion of woody shrubs, and to test its ability to reproduce observed spatial differences in response to drought in the twentieth century. The model{\textquoteright}s performance leads us to argue that vertical and lateral connectivity are key emergent properties of the ecosystem, which both control its behaviour and provide indicators of its state. If this argument is shown to be compatible with field observations, the model presented here will provide a more certain approach towards preventing further degradation of semi-arid grasslands.

}, keywords = {patchiness, positive feedback, self-organization, semiarid landscape ecology, spatially explicit model, vegetation patterns}, doi = {10.1890/12-1253.1}, url = {/files/bibliography/14-022.pdf}, author = {Stewart, Jill and A.J. Parsons and John Wainwright and Gregory S. Okin and Brandon T Bestelmeyer and E.L. Fredrickson and W. H. Schlesinger} } @inbook {JRN52673, title = {Management and policy implications of cross-and within-site, long-term studies}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {206-215}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {15}, address = {Springfield, Virginia}, abstract = {

This chapter explains the implications long-term data bring to natural resource management and policy-making.\  It first explains the two perspectives of long-term data, then explains the values brought by the two perspectives to natural resource management.\  The two perspectives are retrospective and predictive:\  long-term data enable us to examine data retrospectively to identify temporal and spatial sensitivities, and to build these historical perspectives into predictive models where we can objectively evaluate potential future scenarios. The values are as follows.\  First, with the understandings gained by retrospectively examining the long-term data, the managers can develop data-based guidelines to direct the appropriate timing and application of management practices.\  Second, long term data provide the opportunity to evaluate policies and programs that have been implemented for resource conservation.\  The ability to evaluate environmental responses following policy implementation provides the data necessary to validate policies or may lead to their subsequent revision.\  Third, long term data collection provides the opportunity for clients, partners, and stakeholders to be engaged in scientific processes. These interactions create opportunities, not only for technology and information transfers, but for users to inform the science and its research directions.\  Fourth, the predictive models built based on long-term data can be used to estimate the effects of a variety of climatic and management scenarios and are critical to informed decision-making and effective communication between natural resource managers and policy makers.

}, keywords = {atmospheric chemistry, climate change, cross-site comparisons, disturbance, ecological response, ecology, ecosystem, EcoTrends, experimental forests, global change, human demography, human population growth, Long Term Ecological Research (LTER), long-term datasets, precipitation, rangeland, rangeland research stations, surface water chemistry}, url = {/files/bibliography/13-029-15.pdf}, author = {Kris Havstad and Joel R. Brown} } @article {JRN53929, title = {Mosses new to New Mexico}, journal = {Evansia}, volume = {30}, year = {2013}, month = {09/2013}, pages = {105-109}, chapter = {105}, abstract = {

A bryophyte inventory was conducted in the Valles Caldera National Preserve (VCNP), New Mexico, from 2009 to 2011. Specimens representing 113 species of bryophytes were collected. Of those bryophytes, seven of the mosses were new to New Mexico: Atrichum tenellum (R!hling) Bruch \& Schimper, Dicranum tauricum Sapjegin, Orthotrichum pallens Bridel, Sphagnum girgensohnii Russow, Tortella fragilis (Hooker \& Wilson) Limpricht, Tortella tortuosa (Hedwig) Limpricht var. fragilifolia (Juratzska) Limpricht, and Warnstorfia exannulata (Hedwig) Loeske.

}, keywords = {bryophyte, inventory, moss, New Mexico, Valles Caldera National Preserve}, doi = {10.1639/079.030.0301}, url = {/files/bibliography/13-035.pdf}, author = {Kirsten B. Romig and Allred, Kelly} } @article {49870, title = {Managing livestock using animal behavior: Mixed-species stocking and flerds}, journal = {Animal}, year = {2012}, month = {02/2012}, pages = {1-11}, chapter = {1}, abstract = {Mixed-species stocking can foster sound landscape management while offering economic and ecological advantages compared to mono-species stocking.\  Producers contemplating a mixed-species enterprise should reflect on several considerations before implementing this animal management strategy.\  Factors applicable to a particular producer\’s landscape must be considered together with goals and economic constraints before implementing mixed-species stocking.\  A major consideration when using mixed-species stocking is how to deal with predation losses, especially among small ruminants.\  An approach being adopted in some commercial operations capitalizes on using innate animal behaviors to form cohesive groups of two or more livestock species that consistently remain together under free-ranging conditions.\  These groups are referred to as flerds.\  The mixing of a flock of sheep and/or goats with a herd of cattle into a flerd has been shown to protect sheep and goats from coyote predation as well as offering other husbandry advantages.\  Some of the added advantages include more efficient conversion of forage into animal protein.\  Creation of flerds, their maintenance and advantages are discussed.}, keywords = {animal behavior, bonding, livestock, predation}, doi = {10.1017/s175173111200016x}, url = {/files/bibliography/12-006.pdf}, author = {D.M. Anderson and E.L. Fredrickson and Richard E. Estell} } @proceedings {JRN54537, title = {Molecular markers for addressing the genetic consequences of fragmentation on black grama (Bouteloua eriopoda) grasslands}, volume = {PS 105-200.}, year = {2012}, month = {08/2012}, publisher = {Ecological Society of America Proceedings}, address = {Portland, Oregon}, abstract = {Grasses and grasslands are among the most important biological systems on the planet, providing habitat for wildlife, forage for grazers, and grain for animal and human consumption. Bouteloua eriopoda (black grama) is a key species of the grasslands that once covered large parts of the Northern Chihuahuan Desert. Over the last 150 years these grasslands have experienced a significant reduction in geographic coverage as a result of creosote and mesquite shrubland encroachment. The genetic consequences of reduced population size and fragmentation on black grama, or other grasslands, remains unclear. However, research on other wind pollinated plant species suggests that these phenomena result in reduced genetic variation with various potential long-term consequences. In extreme cases a genetic bottleneck can occur, leading to inbreeding depression. Here we present the development of microsatellite and AFLP-based marker systems in black grama for future investigations focusing on spatial patterns of genetic diversity in black grama. Microsatellite loci were developed using an established restriction endonuclease and di/tri-nucleotide repeat enrichment protocols followed by subsequent extensive screening of candidate loci. In addition, six selective AFLP primer combinations were screened for reproducibility and recovery of polymorphic loci. Preliminary results from the analysis of ten individuals for each of five populations of black grama identify nine microsatellite loci that amplify well. However, little genetic diversity is observed within or between populations with these loci. AFLP analyses across the same populations have identified three selective primer combinations (MseI-CTA/EcoRI-AT, MseI-CTA/EcoRI-TT, and MseI-CTA/EcoRI-AC) that amplify well and that together result in 275 polymorphic loci from 376 total loci (73\% polymorphic). In contrast to the genetic variation observed with the available microsatellite markers, the preliminary AFLP data identify considerably more variation within and between populations.}, author = {Heneghan, Allison F. and Hasan, Nabeeh A. and C. Donovan Bailey and Debra C. Peters} } @article {49890, title = {Mapping rangelands with unmanned aircraft}, year = {2012}, month = {03/2012}, pages = {40-44}, abstract = {

At the Jornada Experimental Range in southern New Mexico, ongoing research is aimed at determining the utility of UAS for rangeland mapping and monitoring and developing an operational UAS-based remote sensing program for ecological applications.

}, url = {files/bibliography/12-ProSurveyMag-Laliberte.pdf}, author = {Andrea S. Laliberte} } @article {49905, title = {Manipulating sandpaper oak for livestock and wildlife forage}, number = {663}, year = {2012}, month = {09/21/2012}, institution = {New Mexico State University}, address = {Las Cruces}, abstract = {

Sandpaper oak is a com\¬mon woody plant in many parts of the Southwest. Cattle and deer use sandpaper oak as part of their diet in late spring to early summer when other forage is limited. Mowing may be one method to alter the palatability and/or nutritional value of this plant species. We examined effect of spring and fall mowing on the nutritional quality and secondary chemistry content of sandpaper oak. Both protein and lignin were positively affected by mowing treatments. Crude protein of young leaves was typically higher in mowed treatments than in unmowed areas, but was not different for spring and fall mowing treatments. Lignin content of both young and mature leaves was lowest for the fall mowing treatment. Condensed tannins increased with leaf maturity, while total phenolics were greater in young leaves. Condensed tannin content of leaves in the two mowing treatments did not differ. Total phenolics were lower in leaves from the growing season mowing treatment than from the dormancy mowing (second year only). Crude protein content of both young and mature leaves of mowed oak was higher in fall than surrounding grasses collected at the same time. New growth from mowed sandpaper oak could be a protein source for cattle and wildlife during certain times of year. Tannins and phenolics can decrease palatability, impair digestibility and rumen protein dynamics, and can be toxic at high intake levels. Toxicity should be less problematic when rangelands are lightly to moderately grazed and contain adequate plant diversity.

}, url = {/files/bibliography/12-035.pdf}, author = {Smallidge, S.T. and Goodloe, S. and Terrell T. Baker and Wood, M. K. and Richard E. Estell} } @proceedings {JRN54547, title = {Modeling erosion in a southern New Mexico watershed using agwa: Sensitivity to variations of input precision and scale}, volume = {p. 0217}, year = {2011}, month = {01/2012}, publisher = {Society for Range Management}, address = {Spokane, Washington}, abstract = {Rangeland environments are particularly susceptible to erosion due to extreme rainfall events and low vegetation cover. Landowners and managers need access to reliable erosion evaluation methods in order to protect productivity and hydrologic integrity of their rangelands and make resource allocation decisions. Predicting erosion and its impacts, however, is a challenge due to the spatially variable nature of erosion and the difficulty of measuring it. One erosion model, the automated geospatial watershed analysis (AGWA), uses broad-scale GIS layer inputs to model erosion over entire watersheds to predict relative erosion rates and identify areas where erosion is high. In this research we conducted a sensitivity analysis of the AGWA model, to determine how varying the precision and scale of model inputs affects the magnitude and spatial distribution of erosion predictions. We compared AGWA outputs from three different scales and precisions of input data from a private ranch in Grant County, New Mexico: detailed vegetation and soils input layers derived from remote sensing and field measurements, ecological-site state mapping, and AGWA national-scale vegetation and soils layers. Additionally, erosion hotspots identified by AGWA from each input set were compared to locations within the ranch using rangeland health indicators to determine how AGWA predictions were sensitive to scale and precision in predicting areas susceptible to extreme erosion. The results of this study demonstrate how the AGWA model can be used to identify locations vulnerable to erosion and determine what scale of input is necessary to make useful predictions.}, author = {Sarah Burnett and Jason W. Karl and Laurie Abbott} } @proceedings {JRN54529, title = {Multispectral remote sensing from unmanned aircraft: development of workflows and comparison with WorldView-2 data}, volume = {CD ROM}, year = {2011}, month = {03/2012}, publisher = {American Society for Photogrammetry and Remote Sensing}, address = {Sacramento, CA}, abstract = {Unmanned aircraft systems (UAS) have seen increasing use in remote sensing of natural resources in recent years. Relatively low operation costs, ability to rapidly revisit the same location, and very high resolution imagery offer new opportunities for remote sensing applications and comparison with satellite imagery. Most digital cameras mounted on UAS deliver high spatial resolution imagery, but the low radiometric and spectral resolution has limits for vegetation mapping. We integrated a lightweight multispectral camera (Mini MCA 6, Tetracam, Inc.) into a BAT 3 UAS. The 6-band camera acquires 10-bit data from the visible to the near infrared spectrum, controlled by interchangeable filters, here designed to acquire data with band centers at 450, 550, 650, 720, 750, and 850 nm. Imagery was acquired at a flying height of 210 m, with a nominal GSD of 14 cm, over arid shrubland in southern New Mexico. We developed a custom approach for band-to-band registration and evaluated registration errors. Batch processing algorithms were developed for conversion of raw to tif file format, band-to-band registration, bit conversion, band stacking, and radiometric correction for convenient and fast processing of hundreds of UAS images. An empirical line method was used to fit digital numbers to field measured reflectance spectra. Spectral information derived from the orthorectified UAS mosaic was compared with data derived from a WorldView-2 image corrected atmospherically using ATCOR. We obtained good agreement (R2=0.82) for vegetation and soil reflectance values for the two data sources, especially in the red and near infrared bands. This demonstrates that high resolution multispectral UAS imagery shows great promise as ground truth for WorldView-2 data. An object-based classification of the UAS mosaic showed good spectral separation between arid land shrubs and grasses. We discuss challenges encountered in the multispectral image processing workflow and potential opportunities for multispectral, multi-scale image fusion.}, author = {Andrea S. Laliberte and A. Rango} } @article {49957, title = {Multispectral remote sensing from unmanned aircraft: image processing workflows and applications for rangeland environments}, journal = {Remote Sensing}, volume = {3}, year = {2011}, month = {11/2011}, pages = {2529-2551}, chapter = {2529}, abstract = {Using unmanned aircraft systems (UAS) as remote sensing platforms offers the unique ability for repeated deployment for acquisition of high temporal resolution data at very high spatial resolution. Multispectral remote sensing applications from UAS are reported in the literature less commonly than applications using visible bands, although light-weight multispectral sensors for UAS are being used increasingly. . In this paper, we describe challenges and solutions associated with efficient processing of multispectral imagery to obtain orthorectified, radiometrically calibrated image mosaics for the purpose of rangeland vegetation classification. We developed automated batch processing methods for file conversion, band-to-band registration, radiometric correction, and orthorectification. An object-based image analysis approach was used to derive a species-level vegetation classification for the image mosaic with an overall accuracy of 87\%. We obtained good correlations between: (1) ground and airborne spectral reflectance (R2 = 0.92); and (2) spectral reflectance derived from airborne and WorldView-2 satellite data for selected vegetation and soil targets. UAS-acquired multispectral imagery provides quality high resolution information for rangeland applications with the potential for upscaling the data to larger areas using high resolution satellite imagery.}, keywords = {classification, multispectral, reflectance, Unmanned AircraftSystem (UAS)}, doi = {10.3390/rs3112529}, url = {/files/bibliography/11-034.pdf}, author = {Andrea S. Laliberte and Goforth, Mark A. and Caitriana Steele and A. Rango} } @conference {49984, title = {Multiscale drivers of spatially variable grass production and loss in the Chihuahuan Desert}, booktitle = {96th ESA Annual Meeting, Earth Stewardship: Preserving and enchancing earth{\textquoteright}s life-support systems}, year = {2011}, month = {08/2011}, publisher = {ESA}, organization = {ESA}, address = {Austin, TX}, abstract = {Historic regime shifts from grass- to shrub-dominated states have been widespread in the Chihuahuan Desert and other arid and semiarid regions globally. These patterns of grass production and shifts to shrub dominance are spatially variable, and show a weak correlation with precipitation, suggesting that drivers and processes at different spatial and temporal scales are important determinants of the production and recruitment of grasses. Using long-term data from the Jornada Basin USDA-LTER site, we tested the hypothesis that spatially contagious processes of soil redistribution and shrub invasion can overwhelm the importance of fine-scale drivers (e.g., precipitation, soil depth, vegetation composition) to explain variation in grass production and loss. We found that both fine-scale drivers and contagious spatial processes explain variation in grass production in different parts of the landscape. Grass production on locations surrounded by stable soils is primarily a function of precipitation, soil characteristics, and vegetation composition. However, locations in close proximity to invasive shrubs and erosive soils have poor relationships with local drivers. In these locations, spatial processes of sand deposition and dune formation associated with invading shrubs limit the ability of grasses to exploit otherwise favorable conditions for establishment and growth. These results suggest that focusing on fine-scale processes, such as competition, is of limited utility when spatial processes interact with broad-scale drivers to produce observed patterns. A more explicit focus on multiple interacting spatial and temporal scales is often necessary to more fully understand significant ecological regime shifts.}, author = {Pillsbury, Finn C. and Debra C. Peters and Jin Yao and Gregory S. Okin} } @proceedings {JRN54528, title = {Modeling streamflow from snowmelt in the upper Rio Grande}, volume = {Session 16, p 17.}, year = {2011}, month = {11/2011}, publisher = {American Water Resources Association}, address = {Albuquerque, New Mexico}, abstract = {Annual snowpack in the high elevation snowsheds of the Upper Rio Grande (URG) Basin is a vital source of surface water for irrigated agriculture in New Mexico. Maximum streamflow from the annual snowpack usually occurs in early May for the southernmost snowsheds (e.g., Ojo Caliente) and at the end of May for northernmost snowsheds (e.g., Del Norte). Increases in average daily temperatures due to climate warming will affect the timing of maximum streamflow from snowmelt and this will have repercussions for water storage and supply during the growing season. Moreover, different climate change scenarios indicate less reliable precipitation, which could affect the quantity of water from melting snow. It is essential that we understand and plan for potential changes in the amount of water from snowmelt. We have been assembling input data for the Snowmelt Runoff Model (SRM) for use in 24 important snow basins in the URG. We present the results of this model for a good snow year (2005) and a poor snow year (2002) for a selection of basins along a south-north transect. SRM is driven with climate data (temperature and precipitation) and remotely estimated snow cover data. Once SRM simulates runoff at acceptable levels for snow basins for both good and poor snow years, we will be able to use data from global climate models to predict how the timing of maximum streamflow and quantity of water from snowmelt will change.}, author = {Caitriana Steele and A. Rango} } @conference {JRN54482, title = {Mapping land cover in urban residential landscapes using fine resolution imagery and object-oriented classification}, booktitle = {American Society for Horticulture Science Conference}, year = {2010}, month = {08/2010}, publisher = {American Society for Horticulture}, organization = {American Society for Horticulture}, address = {Palm Springs, CA}, abstract = {

A knowledge of different types of land cover in urban residential landscapes is important for building social and economic city-wide policies including landscape ordinances and water conservation programs. Urban landscapes are typically heterogeneous, so classification of land cover in these areas requires fine resolution imagery in order to capture the level of detail required for effective decision-making. The main objective of our research was to characterize land cover proportions by zip code in Albuquerque, New Mexico. To achieve this objective, we classified a random selection of residential land parcels using object-oriented classification and fine spatial resolution photographic imagery. Vector data representing land parcels within the city limits of Albuquerque, zip codes, and land-use were used to create an integrated Geographic Information System (GIS) database. The database was stratified based on 16 zip codes, then 30 parcels were randomly selected from each zip code. Orthorectified, true color aerial photographs acquired in 2008 with 0.15m (0.5 ft) resolution were used to identify irrigated areas (trees, shrubs and grass), swimming pools and non-irrigated areas using the object-oriented classification module embedded in ENVI EX 4.7.1software. Imagery was first segmented to produce meaningful image objects. These objects were then classified using a nearest neighbor algorithm. The variables used in this classification were: spatial, textural and spectral attributes. Then, we assessed classification accuracy and calculated landscape feature areas. Accuracy assessment was calculated using confusion matrices. Results showed that user{\textquoteright}s and producer{\textquoteright}s accuracy for different classes in the six zip codes ranged from 73 to 100\%. Overall classification accuracy ranged from 80 to 90\%. Most zip codes had a common landscape with 75\% trees and 25\% shrubs and turf. One zip code had 50\% trees, 40\% grass and 10\% shrubs. Around half of the parcels in three zip codes (87104, 87106, and 87110) had 40\% of the parcel irrigated, while 80\% of parcels in the other zip codes had irrigated areas of about 20\%. Knowledge of these land cover proportions will provide useful

}, author = {Al, Kofahi S. and Caitriana Steele and D. VanLeeuwen and St. Hilaire, Rolston} } @article {50026, title = {Measurement of monoterpenes and sesquiterpenes in serum, plasma, and rumen fluid from sheep}, journal = {Animal Feed Science and Technology}, volume = {158}, year = {2010}, pages = {104-109}, abstract = {Studies involving the consumption, metabolism, and elimination of terpenes by small ruminants consuming terpene-laden shrubs as well as those exploring the potential for natural products as rumen modifiers could benefit from a procedure that measures terpenes in both blood and rumen fluid and that is suitable for either serum or plasma. The objective of this study was to modify an existing procedure for plasma utilizing solid phase extraction/gas chromatography, and extend its use for measurement of structurally diverse mono- and sesquiterpenes in three fluids (serum, plasma, and rumen fluid) from sheep. Generally, terpene recovery was lower from rumen fluid than from serum or plasma, although the extent and direction of differences varied among chemicals. Fourteen terpenes (camphene, {\ss}-pinene, a-terpinene, p-cymene, cis-{\ss}-ocimene, 1,8-cineole, {\textquoteright}-terpinene, terpinolene, linalool, camphor, longifolene, {\ss}-caryophyllene, a-humulene, and caryophyllene oxide) were recovered from serum at approximately 100\%. Recovery from rumen fluid was lower than for serum or plasma for most terpenes, but eight terpenes (p-cymene, 1,8-cineole, cis-sabinene hydrate, terpinolene, borneol, terpin-4-ol, a-terpineol, and caryophyllene oxide) were recovered at near 100\%. Yet, 15 terpene recoveries were below 75\% (tricyclene, a-pinene, camphene, sabinene, {\ss}-pinene, myrcene, 2-carene, 3-carene, a-terpinene, cis-{\ss}-ocimene, limonene, {\textquoteright}-terpinene, longifolene, {\ss}-caryophyllene, and a-humulene). Oxygenated monoterpenes were typically recovered in greater quantities and hydrocarbon monoterpenes were least effectively recovered with this method. The procedure is suitable for measurement and recovery adjustment of terpenes from serum, plasma, and rumen fluid of sheep.}, keywords = {plasma, recovery, rumen fluid, ruminants, serum, sheep, shrub, terpene}, url = {/files/bibliography/10-04.pdf}, author = {Richard E. Estell and S. A. Utsumi and Andr{\'e}s F. Cibils} } @conference {JRN54493, title = {Mesquite: A long view}, booktitle = {16th Biennial Mogollon Archeology Conference}, year = {2010}, month = {10/2010}, publisher = {16th Biennial Mogollon Archeology Conference}, organization = {16th Biennial Mogollon Archeology Conference}, address = {Las Cruces, NM}, abstract = {Mesquite (Prosopis glandulosa) is among the most successful plants in Northern M{\'e}xico and America{\textquoteright}s arid Southwest. Mesquite optimizes pollinator services and reproductive effort, resulting in seeds that persist in herbivore digestive tracts and soil seed banks for extended periods. An extensive root system fully occupies the soil profile long distances from its base, allowing it to harvest water and nutrients with extraordinary efficiency. Root nodules harbor nitrogen-fixing bacteria allowing mesquite to overcome usual nitrogen limitations. Mesquite survival is determined early, but once established, it is long-lived, often benefiting from hardships killing most plants. So with mesquite{\textquoteright}s superior adaptations and competitive advantage, why has it only recently dominated desert landscapes? An answer may reside in the literature housing the knowledge of anthropologists and archaeologists studying the Jornada Mogollon, and prehistoric peoples of North America{\textquoteright}s warm deserts. Extensive use of mesquite by prehistoric peoples maybe a mechanism for dispersal of desert shrubs during the Holocene and controlling its distribution prior to European influence. A long-view of mesquite demography appears essential for reinterpreting our relationship with mesquite. A relationship that now cost millions of dollars annually to control its abundance and provide for lost ecosystem services.}, author = {E.L. Fredrickson and Curtis H. Monger and Guevada, Eduardo P.} } @conference {50035, title = {Monitoring and assessing global impacts of roads and off-road vehicle traffic}, booktitle = {Society for Range Management}, volume = {63rd Society for Range Management}, year = {2010}, address = {Denver, CO}, abstract = {Rapid increases in the number of vehicles, urban sprawl, exurban development and infrastructure development for energy and water have led to dramatic increases in both the size and extent of the global road network. Anecdotal evidence suggests that off-road vehicle traffic has also increased in many areas, particularly in parts of many developing countries where the road network is non-existent or poorly maintained. The impacts of roads, road networks and off-road vehicle traffic on rangelands have received little attention. This is in part due to the complexity of monitoring and assessing their effects on rangeland health and productivity, including hydrology and wildlife populations, across multiple spatial scales. We briefly review current challenges, and present new strategies for applying new and existing tools to monitoring and assessment of road and off-road vehicle impacts at multiple spatial scales. Tools include an adaptation of Interpreting Indicators of Rangeland Health, LIDAR, laser rangefinders, various types of penetrometers and a checklist for describing hydrologic. We illustrate the application of these tools with examples from a several pilot studies on unpaved road networks in the United States and Mongolia. We conclude by showing how currently available online programs can be used to help design cost-effective monitoring and assessment systems to answer specific questions about road impacts at multiple spatial scales.}, keywords = {interpreting indicators, off-road, rangeland health, vehicles}, author = {Jeffrey E. Herrick and Danielle Duni and Jason W. Karl and Justin Van Zee} } @conference {JRN54492, title = {Making spatial predictions of rangeland ecosystem attributes using regression kriging}, booktitle = {Society for Range Management}, year = {2010}, month = {02/2010}, publisher = {Society for Range Managment}, organization = {Society for Range Managment}, address = {Denver, CO}, abstract = {Sound rangeland management requires accurate information on condition over large landscapes. Typical approaches to making spatial predictions rangeland condition attributes (e.g., shrub or bare ground cover) are via regression between field and remotely-sensed data. This works well in some situations but has limited utility when correlations between field and image data are low and does not take advantage of all information contained in the field data. I compared, for three rangeland attributes (percent cover of shrubs, bare ground, and cheatgrass [Bromus tectorum L.]) in a southern Idaho study area, spatial predictions from generalized least-squares (GLS) regression to a geostatistical interpolator, regression kriging (RK) that combines GLS regression with spatial interpolation of the residuals to improve predictions of rangeland condition attributes over large landscapes. I employed a remote-sensing technique, object-based image analysis (OBIA), to segment Landsat TM 5 images into polygons (i.e., objects) because previous research has shown that OBIA yields higher image-to-field data correlations. Spatial dependence, the decrease in autocorrelation with increasing distance, was strongest for bare ground (samples auto correlated up to a distance [i.e., range] of 12,646m), but present in all three variables (range of 3,653m and 768m for shrub and cheatgrass cover, respectively). As a result, RK produced more accurate results than GLS regression alone for all three variables measured by cross-validated root mean-squared error. Additionally, the ability to map how prediction confidence changes with distance from field samples is a significant benefit of regression kriging and makes this approach suitable for landscape-level assessments and management planning.}, author = {Jason W. Karl} } @article {50036, title = {Monitoring and assessment based on ecological sites}, journal = {Rangelands}, volume = {32}, year = {2010}, month = {12/2010}, pages = {60-64}, chapter = {60}, abstract = {

The importance of monitoring and assessment of rangeland systems is generally accepted, buteh importanc eand benefits of monitoring based on a foundation of ecological site potential is less well understook. The concept of ecological sitesand their current implementation via NRCS ecological site descriptions and associated GIS spatial data layers provides a robust and scalable framework for rangeland monitoring and assessment. An ecological site provides a standard reference for land management, research and monitoring. The ecological site description informs managers as to what kinds of changes can be expected in response to management or disturbance and provides a reference for the interpretation of monitoring and assessment data. In addition, there are many practical uses of ecological sites for designing programs and collecting and analyzing data for rangeland monitoring and assessment. In this paper we describe a monitoring and assessment framework based on ecological sites and present examples for several current and potential applications of ecological sites to rangeland monitoring and assessment.

}, url = {/files/bibliography/10-039.pdf}, author = {Jason W. Karl and Jeffrey E. Herrick} } @article {JRN52689, title = {Manipulating sheep browsing levels on Coyote Willow (Salix exigua) with supplements}, journal = {Sheep and Goat Research Journal}, volume = {25}, year = {2010}, pages = {32-38}, chapter = {32}, abstract = {

Macronutrients and additives have been used to suppress or promote intake of upland tannin-containing browse species by livestock, but to our knowledge this technique has not been applied to sheep that feed on tannin-containing species in riparian areas. The objective of this study was to determine the effect of four supplement regimes on coyote willow (Salix exigua) intake by sheep during the dormant and growing seasons. Twelve Western White Face lambs (48 \± 4.5 kg) were placed in individual pens and assigned to one of four treatments which consisted of a basal diet of sudangrass and supplements predicted to either suppress (whole corn or quebracho tannin) or promote (cottonseed meal or polyethylene glycol, PEG) willow intake. Each of the four supplements was tested with dormant and growing willow in a Latin rectangle design with 3 periods and 6 lambs per group. Basal diet (sudangrass) intake was affected by neither promoter nor suppressor treatments in either season. Cottonseed meal effectively promoted intake of willow compared to the control and PEG treatments (P\< 0.05) in the dormant season. No difference was detected between the control, quebracho tannin, and whole corn treatments, although the latter tended to depress dormant willow intake of lambs. None of the treatments altered intake of coyote willow in the growing season trials. Protein and possibly corn-based supplements may be effective tools to manipulate sheep browsing levels of Salix exigua but need to be tested in a field setting before management strategies with supplementation can be applied.

}, keywords = {cottonseed meal, polyethylene glycol, quebracho tannin, tannins, targeted grazing, whole corn}, url = {/files/bibliography/10-031.pdf}, author = {Lujan, Adam L. and S. A. Utsumi and Smallidge, S.T. and Terrell T. Baker and Richard E. Estell and Andr{\'e}s F. Cibils and S. Ivey} } @article {JRN54488, title = {Monitoring rangeland health: A guide for pastoralists and other land managers in Eastern Africa}, year = {2010}, edition = {Version II}, abstract = {

This guide provides is written for people who want to design and implement a simple rangeland monitoring program in eastern Africa that is based on ecological principles and reflects the status of key ecological processes. It outline a series of steps that enable community members and other land managers to decide what, where, when, and how to monitor, as well as how to interpret and apply the results of their monitoring. It is based on a simple set of methods for monitoring plant and ground cover, gaps between plants, plant height, and plant density. It also provides instructions for collecting basic site information and observational data for interpreting monitoring results. The methods require only a pencil, a 1m stick, and a single datasheet, but generate data that are for the most part comparable with those collected using standardized monitoring protocols such as those applied by the United States National Resources Inventory (NRI).

}, author = {C. Riginos and Jeffrey E. Herrick} } @conference {JRN54485, title = {Microbial diversity of rizosphere in two saline chenopodiaceaes}, booktitle = {13th International Symposium on Microbial Ecology}, year = {2010}, month = {03/2010}, publisher = {International Symposium on Microbial Ecology}, organization = {International Symposium on Microbial Ecology}, address = {Seattle, WA}, abstract = {Saline environments can be found on all continents and in most countries. They consist in two primary types: those that arose from seawater and those which come from nonseawater sources. The latter contain different ion ratios where the dominant anion is typically carbonate. Plants native to saline habitats are exposed to various levels of moisture and salinity stress during their life cycle. We analyzed both soil and rhizospheric microbial communities, in plants from these environments. One of the genus Suaeda from central Mexico and other which belongs to the genus Atriplex fom the Chihuahuan desert in Nuevo Mexico, USA. In order to analyze quantitatively the microbial community rizospheric soil and soil bulk samples were processed and analyzed by traditional surface spread plating methods. The samples were plated in at least sixteen different culture media: modified R2A; modified casamino acids; BHAP; PDA; TYA and YCED medium. Each medium contained either 4\% or 10\% solar salt (w/v), and its pH was adjusted to either 7.0 or 9.3. Molecular analysis was also performed. Total community DNA was extracted in samples of rizospheric soil. 16s rDNA fragments amplified by PCR from soil DNA were analyzed by denaturing gradient gel electrophoresis (DGGE). Plate count methods show a high concentration of free living bacteria, 5.9x108 CFU/g, and fungi, 2.4x104 CFU/g. In bulk soil bacterial counts were is 3.0x108 CFU/g, whereas fungal counts were only is 1x103 CFU/g. Difference was found in media formulations due to high salt concentration or high pH. Medium R2A allowed the highest cultivable microbial diversity. DNA was extracted from four selected soil samples and PCR amplified with specific 16S rDNA gene primers for both bacteria and actinomycetes. The products were analyzed under different DGGE conditions. Clear differences in microbial diversity are found in rhizosphere vs bulk soil communities, as well as in cultivable vs non cultivable communities. Implications of these results in soil management and restoration are discussed.}, author = {Ruiz-Font, Angelica and Trejo-Estrada, Sergio and M.E. Lucero} } @conference {50089, title = {Multiscale variability of soil aggregate stability: implications for rangeland hydrology and erosion}, booktitle = {62nd Society for Range Mangement Annual Meeting}, year = {2009}, month = {February 8-12, 2}, pages = {07-11}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Alb., NM}, abstract = {Conservation of soil and water resources in rangelands is a crucial step in stopping desertification processes. The formation of water-stable soil aggregates reduces soil erodibility and can increase infiltration capacity in many soils. Soil aggregate stability is highly variable at scales ranging from individual aggregates to bioclimatic regions due to complex interactions of soil texture, soil organic matter, soil organisms, vegetation and surface disturbance. Variability in soil aggregate stability at all scales has important implications for rangeland hydrology and erosion. We conducted field soil aggregate stability tests at multiple scales (plot, landscape, and regional) throughout the western United States and in areas with varying degrees of vehicle-related disturbances. Additionally, small plot scale rainfall simulation experiments were conducted in conjunction with soil stability measures. Results demonstrate the scale-dependent nature of variability in soil aggregate stability, particularly within a disturbance gradient. The implications of this variability for hydrology and erosion are explored by contrasting variability in soil stability among scales, disturbance types and regions. Other site properties related to hydrology and erosion, including soil texture, vegetation, and cover and distribution bareground, are used to highlight possible mechanisms. In rangeland monitoring and assessment activities, the application of average soil stability values over large areas can be appropriate. Soil degradation at small scales, however, can result in disproportionally large increases in soil erosion and run-off. Results from our studies and related literature indicate that large variability occurring at relatively small scales should be considered for multi-scale estimates of changes in rangeland hydrology and erosion.}, keywords = {aggregate, desertification, hydrology, stability}, author = {Danielle Duni and Jeffrey E. Herrick and K. Spaeth and N. Barger and Justin Van Zee and Jayne Belnap} } @article {50127, title = {Mountain Snow Equals River Flow}, volume = {Spring}, year = {2009}, month = {2009}, pages = {22-23}, publisher = {New Mexico State University}, abstract = {Research use $15 million EPSCoR grant to track impact of climate change on water supplies (Rango)}, url = {http://researchmag.nmsu.edu/2009_SP/feature_mountain.html}, author = {Olmsted, A.} } @article {50163, title = {Modeling the effects of historical vegetation change in near-surface atmosphere in the Northern Chihuahuan Desert}, journal = {Journal of Arid Environments}, volume = {72}, year = {2008}, note = {Boundary Layer Meteorology rejected; submitted to Journal of Arid Environments 10/2007. Title change}, month = {08/2008}, pages = {1897-1910}, abstract = {

Our goal was to evaluate effects of broad-scale changes in vegetation from grasslands to shrublands over the past 150 years on near-surface atmosphere over the Jornada Experimental Range in the northern Chihuahuan Desert, using a regional climate model. Simulations were conducted using 1858 and 1998 vegetation maps, and data collected in the field. Overall, the vegetation shift led to small changes in sensible heat (SH) and an increase in latent heat (LH). The impacts of shrub encroachment depended on shrubland type: conversion from grass to mesquite cools the near-surface atmosphere and from grass to creosotebush warms it. Higher albedo of mesquite relative to grasses reduced available energy, which was dissipated mainly as LH due to the deeper root system in mesquite. In creosotebush-dominated areas, a decrease in albedo, an increase in roughness length and displacement height contributed to the SH increase and warmer temperatures. Sensitivity simulations showed that an increase in soil moisture content enhanced shrub LH and a reduction in mesquite cover enhanced the temperature differences. The observed shift in vegetation led to complex interactions between land and surface fluxes, demonstrating that vegetation itself is a weather and climate variable as it significantly influences temperature and humidity.

}, keywords = {Albedo, change, characteristics, Chihuahuan, desert, historical, northern, vegetation}, doi = {10.1016/j.jaridenv.2008.05.012}, url = {/files/bibliography/08-029.pdf}, author = {Beltran-Przekurat, A. and R.A. Pielke and Debra C. Peters and K. A. Snyder and A. Rango} } @inbook {50194, title = {Modeling Snowmelt Runoff}, booktitle = {Principles in Snow Hydrology}, year = {2008}, month = {July 2008}, pages = {266-305}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, chapter = {Chapter 10}, address = {Cambridge, NY}, abstract = {Hydrologic models used to predict streamflow can be generally classified as either deterministic or stochastic and as either lumped-parameter or distributed (Beven 2000). Deterministic models predict a single value of streamflow from a given set of input variables, while stochastic models predict a range of possible outcomes based upon the statistical distributions of input variables. Nearly all of the snowmelt models used to continuously predict streamflow from snowmelt are deterministic, but a type of statistical model has been historically used to great advantage to predict seasonal totals of streamflow using measured snowpack and precipitation data each spring. These models are in widespread use in the western United States to forecast spring runoff.}, keywords = {deterministic, forecast, hydrologic models, modeling, snowmelt runoff, statistical model, stochastic}, url = {http://www.cambridge.org/us/catalogue/catalogue.asp?isbn=0521823625}, author = {D. DeWalle and A. Rango} } @article {50222, title = {Mongolia{\textquoteright} s rangelands: Is livestock production the key to the future?}, journal = {Frontiers in Ecology and the Environment}, volume = {6}, year = {2008}, month = {September 2008}, pages = {386-391}, abstract = {Approximately half of the world{\textquoteright}s land areas is rangeland. Over 1.5 billion people live on or immediately adjacent to this land type. Common to these rangelands are over 1 billion domesticated animals, primarily cattle, sheep and goats that are managed by pastoralists. The ruminant digestive system common to these livestock species evolved over 20 million years ago and is a mutualistic digestive system that break cellulose bonds to free masses of metabolizable energy present it the nature and introduced forages of these rangelands. Approximately 10\% of eh world{\textquoteright}s population are pastoralists, and many of these people live at poverty levels. However, these landscapes can also provide additional goods and services other than food and fiber. This manuscript is a viewpoint article that debates the capacity of pastoralists, specifically those in Mongolia, to develop other goods and services in order to increase their standard of living while maintaining a sustained capacity to produce food and fiber A key need for managing a diverse set of goods and services form any landscape, including grasslands, of Mongolia, is knowledge of the values of alternative ecosystem services and their resulting economic opportunities. This knowledge is unavailable at this time except for a few services with market opportunities.}, keywords = {future, journal, livestock, Mongolia, rangeland}, url = {/files/bibliography/08-035.pdf}, author = {Kris Havstad and Jeffrey E. Herrick and Tseelei, E.A.} } @article {50249, title = {A multi-source portable light emiting diode spectrofluorometer}, journal = {Applied Speactroscopy}, volume = {62}, year = {2008}, month = {March 1, 2008}, pages = {327-332}, abstract = { A portable luminescence spectrofluorometer weighing only 1.5 kg that uses multiple light emitting diodes (LEDs) as excitation sources was developed and evaluated. Excitation using a sequence of seven individual broad-band LED emission sources enabled the generation of excitation-emission spectra using a light weight (\<1.5 kg) spectrometer. Limits of detection for rhodamine 6G, rhodamine B and fluorescein were 2.9, 3.2, and 11.0 nM, respectively. Generation of excitation-emission matrices (EEMs) enabled the analysis of samples containing mixtures of rhodamine B and fluorescein. Buffered saline plant and animal feed extracts were also analyzed using this instrument. These samples included the woody plants Pistacia lentiscus (Evergreen pistache or Mastic) and Philyria latifolia, and the herbaceous species Medicago sativa (alfalfa), Trifolium spp. (clover), and a feed concentrate. Application of multi-way principal component analysis (MPCA) to the resulting three-dimensional data sets enabled discernment among these various diet constituents.}, keywords = {LED, spectrofluorometer}, url = {/files/bibliography/08-006.pdf}, author = {S. Obeidat and B. Bai and G.D. Rayson and D.M. Anderson and Puscheck, A.D. and Landau, S.Y. and Glasser, T.} } @conference {50287, title = {Multiple constraints on ecological restoration: Re-establishment of black grama grass (Bouteloua eriopoda) after intensive grazing}, booktitle = {Ecological Society of America Abstracts}, series = {93rd ESA Annual Meetings}, year = {2008}, month = {August 4-8, 2008}, pages = {COS 119-7}, address = {Milwaukee, WI}, abstract = {Climate change may alter potential ecological restoration of semi-arid rangeland. Bouteloua eriopoda (black grama, BOER) is a perennial C4 grass that usually fails to re-establish in degraded rangeland and may be constrained by increased atmospheric CO2 and reduced or seasonally redistributed rainfall. Eighteen contiguous 0.5-ha plots were established in a remnant black grama grassland at the Jornada Experimental Range in the Northern Chihuahuan Desert. Removal of mesquite shrubs (Prosopis glandulosa) and intensive seasonal grazing (none, winter, summer) were applied in a randomized complete block design. From 1996-2000 annual grazing removed 65-85\% of the available forage in 24-36 h, a grazing intensity 30X greater than in the previous 40 years. In 2002 the mean percent cover of BOER was 5.82{\textpm}0.94 in grazed plots compared to 27.3{\textpm}1.33 in ungrazed plots. By 2005 BOER had not re-established. A pair of circular 1 m diameter, 6.35 mm wire mesh exclosures, were randomly located in each of the 18 plots. Annually from 2005-2007 the treatment exclosure of each pair had non-BOER above-ground biomass removed and viable BOER seed planted and fertilized.}, keywords = {abstract, climate change, restoration}, author = {S. Tartowski and D. K. James} } @conference {50300, title = {Measures of daily distribution patterns of cow calf pairs using global positioning systems on both cows and calves}, booktitle = {Society for Range Mangement}, year = {2008}, month = {January 26, 2008}, pages = {2186}, abstract = {GPS collars were used to describe the daily distribution patterns of cows and their calves from 18 to 60 days postpartum on pinyon juniper-shortgrass rangeland in central New Mexico. Eighteen, 3 year old cows and their calves were fitted weekly with GPS collars for seven consecutive weeks. Twenty days with cow calf pair location data for at least 48 consecutive hours were randomly selected. Daily area explored was estimated using the area of the 90\% volume contour predicted with Kernel Analysis in the animal movements extension of ArcVeiw GIS 3.3. Cows daily distance traveled ranged from 2.7 to 6.2 km and they explored between 4.5 and 28.5ha day-1. Calves traveled between 2.2 and 6.1 km day-1 while exploring areas ranging from 1.3 to 16.7ha, of which an average of 5.5 {\textpm} 2.9ha overlapped with the area explored by its mother. Neither daily distance traveled nor area explored by the cow were correlated with calf age, but calves tended to travel longer distances and explore larger areas with increasing age (r=0.37, P= 0.10 and r=0.38, P=0.10, respectively). Cows visited water 85\%, and calves 15\%, of the days sampled. Average distance from water was 0.8 {\textpm} 0.21 km for cows and calves and was positively correlated for both with calf age (r=0.53, P=0.02 and r =0.57, P=0.01 respectively), as was maximum distance traveled from water (r=0.36, P=0.11, and r=0.47, P=0.03, respectively). Cows spent between 4.4 and 15.1 hours total, but never more than 8.3 hours in one event, farther than 100m away from their calves in any 24 hour period. Maximum distance between a calf and its mother was positively correlated with age (r=.50, P=0.02). Search patterns of cows (ratio between daily distance traveled and daily area explored) became considerably more concentrated when they remained in the proximity of their calves.}, keywords = {abstract, abstracts, GPS collars, pinyon juniper}, author = {Wesley, R.L. and Andr{\'e}s F. Cibils and Pollak, E.R. and S.H. Cox and Mulliniks, T. and M.K. Petersen and E.L. Fredrickson} } @conference {50303, title = {Minimum property dataset and sampling requirement tool for soil change studies in soil survey}, booktitle = {Geological Society of America Meeting}, series = {2008 Joint Meetings}, year = {2008}, month = {October 5-9, 200}, pages = {679-9}, address = {Houston, TX}, abstract = {Dynamic soil properties (DSP) are those properties that change over human time scales. The new sampling guide {\textquotedblleft}Soil and Resource Inventory Guide for Dynamic Soil Properties and Soil Change{\textquotedblright} includes a minimum DSP dataset and an interactive tool to determine sampling requirements. The minimum dataset is a common set of properties that will be measured on all DSP projects. In order to help guide soil property selection, a ranking tool was developed and completed by 40 experts in soil survey and pedology, soil biology, agronomy, forestry, rangeland, and hydrology. The ranking tool asked experts to rank properties according to 4 criteria important to soil change and soil survey. They ranked sensitivity to change the most important criteria for selecting a minimum DSP dataset. The highest ranked properties were organic carbon, pH and EC. The multi-scale sample requirement evaluation tool (MSSRET) is an Excel spreadsheet-based tool that can be used to determine the necessary sample requirements at plot and landscape scales for DSP monitoring and comparison studies. It is intended to help in project planning and sample sufficiency assessment. The Guide recommends sampling DSPs in a multi-scale fashion (multiple samples on multiple plots) by soil map unit component phases. Sample and plot requirements are calculated from the desired minimum detectable difference (MDD), the variance of the property at plot and project scales and the level of acceptable error rates. The guide represents a new phase in soil survey that will document DSPs and soil change due to management.}, keywords = {DSP, soil properties}, author = {S.A. Wills and A.J. Tugel and Jeffrey E. Herrick and M.D. Remmenga} } @article {50314, title = {Multiscale variability in soil aggregate stability: Implications for understanding semiarid grassland degradation}, journal = {Geoderma}, volume = {140}, year = {2007}, month = {04/2007}, pages = {106-118}, abstract = {Grassland degradation typifies desertification in many regions of the world. Changes in plant communities and increased soil resource loss and redistribution have been widely documented in degrading grasslands. Increased soil loss and redistribution are commonly associated with changes in soil structure, yet variability in soil structure in arid ecosystems has been little studied. We compared soil aggregate stability in a Chihuahuan Desert grassland at the plant and landscape scales by assessing aggregate stability at four sites in two cover classes (under grass canopy vs. in bare interspace) located within each of three grass cover and land disturbance classes. Soil aggregate stability is a key indicator of soil structure and is correlated with erodibility and water infiltration capacity. To increase measurement sensitivity to changes in soil structure and identify potential early warning indicators for monitoring, we used two different methods for quantifying wet aggregate stability: stability of aggregates \> 0.25 mm was assessed in the laboratory and that of 1.5 mm aggregates was assessed in the field. As expected, soil aggregate stability was significantly higher under grass plants than in plant interspaces (44.2 vs. 38.4\% for the lab test and 4.4 vs. 3.3 stability class for the field test; p \< 0.01). This plant-interspace pattern was consistent at all four study sites, but the absolute values for under plants and in interspaces varied across the landscape. The field test showed higher stability throughout the top 10 cm in plots with higher grass cover throughout the top 10 cm, while disturbance level only affected stability at the soil surface. The laboratory test was insensitive to differences in grass cover and disturbance. High variability at the plant-interspace scale supports earlier work on biogeochemistry, reflecting linkages between the spatial distribution of soil structure, soil organic matter, and nutrient cycling. The established relationship between soil aggregate stability and other soil properties and processes, the relative sensitivity of the field test, and lack of sensitivity of the lab test to differences in grass cover and disturbance support the use of the field test as an indicator for managing both grass cover and soil surface disturbance in arid grasslands. http://www.sciencedirect.com/science/article/pii/S0016706107000912}, keywords = {desertification, grassland degradation, soil aggregate, soil structure, stability, variability}, doi = {10.1016/j.geoderma.2007.03.010}, url = {/files/bibliography/07-017.pdf}, author = {S.B. Bird and Jeffrey E. Herrick and Wander, M.M. and L. W. Murray} } @conference {50339, title = {Managing multi-scale diversity to support multiple ecosystem services in complex landscapes}, booktitle = {Ecological Complexity and Sustainability Abstracts of EcoSummit 2007}, year = {2007}, month = {May 22-26, 2007}, pages = {115 CD-ROM}, address = {Beijing, China}, abstract = {Landscapes around the world are undergoing dramatic changes in response to agricultural intensification, expansion, and abandonment. These changes can simultaneously increase and reduce diversity at different scales. The objective of this paper is to explore the relative importance of the nature, scale and pattern of these changes in determining the effects of land use change (LUC) on ecosystem services including food and fiber production, soil and water conservation and carbon sequestration. We will briefly describe three case studies that illustrate the value of considering diversity at multiple scales when assess the effects of LUC in global agroecosystems. These case studies include (1) expansion and mechanization of quinoa production in the southern altiplano of Bolivia, (2) adoption of an agroforestry system in western Honduras and the potential effects of increased livestock use of crop residues, and (3) agricultural land abandonment and changes inland use patterns in northern Mexico. We will also consider how studying the effects of land use changes at different scales can lead to very different conclusions about their effects on different ecosystem services.}, keywords = {diversity, ecosystem, landscapes, LUC, natur, scale}, author = {Kris Havstad and Jeffrey E. Herrick and Brandon T Bestelmeyer and Huber-Sannwald, B.T. and Liberman, M. and M. Ayarza and Joel R. Brown and J. F. Reynolds} } @conference {50418, title = {Managing Vegetation Dynamics: Soil-geomorphic Maps, State-and-Transition Models, and Remote Sensing}, booktitle = {2005 Ecological Society International Meeting, Ecological Society of America Abstracts}, year = {2006}, month = {January 2006}, pages = {133}, address = {Merida, Yucatan, MX}, abstract = {Vegetation mapping via remote sensing tools is a useful and cost-effective approach for understanding current land use and species habitat patterns, but has limited utility in predicting the future state of vegetation. We describe an approach that couples data-supported, conceptual state-and-transition models with soil-geomorphic mapping and remote sensing of vegetation states to provide maps of potential vegetation and their likely future state under different management scenarios. Soil maps are critical components of this approach that are often unattainable, so we describe an approach to classifying geomorphology-based land types based on landforms and remote-sensed imagery in arid to semiarid zones. The resulting maps reflect management hazards and opportunities for restoration that are not addressed in conventional vegetation maps.}, keywords = {patterns, sensing, soil-geomorphic, species habitat, vegetation}, author = {Brandon T Bestelmeyer and C. T. Monger and Fores Ancira, E. and Jeffrey E. Herrick and Caitriana Steele and Trevino, R.} } @article {50416, title = {A multi-scale classification of vegetation dynamics in arid lands: What is the right scale for models, monitoring, and restoration?}, journal = {Journal of Arid Environments}, volume = {65}, year = {2006}, month = {April 2006}, pages = {296-318}, abstract = {

Measurements of vegetation and soil dynamics used to anticipate (or reverse) catastrophic transitions in arid and semiarid rangelands are often difficult to interpret. This situation is due, in part, to a lack of empirically-based conceptual models that incorporate the effects of multiple processes, scale, spatio-temporal pattern, and soils. Using observations of multitemporal data from the Chihuahuan Desert, we describe a new approach to classifying vegetation dynamics based on multiple scales of vegetation and soil pattern as well as cross-scale interactions. We propose the existence of six types of mechanisms driving vegetation change including 1) stability, 2) size oscillation of plants, 3) loss and reestablishment of plants within functional groups, 4) loss of one plant functional group and replacement by another, 5) spatial reorganization of vegetation patches, and 6) cascading transitions that spread from small to broad scales. We provide evidence for the existence of these mechanisms, the species involved, and the geomorphic components on which they are observed in the Chihuahuan Desert. These mechanisms highlight the kinds of multi-scale observations that are needed to detect or interpret change and emphasize the importance of soil-surface properties for interpreting vegetation change. The classification is potentially general across arid and semiarid ecosystems and links spatial and temporal patterns in vegetation with ecological and geomorphic processes, monitoring, and restoration strategies.

}, keywords = {catastrophic, dynamics, measurements, multiple processes, scale, soil, spatiotermporal, transitions}, doi = {10.1016/j.jaridenv.2005.06.028}, url = {/files/bibliography/06-012.pdf}, author = {Brandon T Bestelmeyer and D. Trujillo and A.J. Tugel and Kris Havstad} } @article {50423, title = {Modeling flow patterns in a small vegetated area in the northern Chihuahuan Desert using QUIC (Quick Urban \& Industrial Complex)}, journal = {Environmental Fluid Mechanics}, volume = {6}, number = {4}, year = {2006}, note = {//USDA//LTER V//Entered 11/20/2006; updated 08/19/2008}, month = {2006}, pages = {359-384}, abstract = {

Sandstorms are frequent in the northern Chihuahuan Desert in New Mexico, an area characterized by open areas lacking vegetation, individual mesquite bushes, and mesquite coppice dunes. Field measurements of sand fluxes and wind velocities over a two year period provided a description of the area {\textendash} suggesting that the {\textquotedblleft}streets{\textquotedblright}, the flat, elongated, non-vegetated areas aligned with the dominant wind directions are the principal sources of wind-dispersed soil and dust. However, since soil erosion and dust movement depend on the pattern, strength, and gradients in the wind field, modeling soil erosion and dust movement requires a continuous wind velocity field. Consequently, air flow patterns at this site were simulated using a semi-empirical mass-consistent diagnostic wind field model: QUIC version 3.5 (Quick Urban \& Industrial Complex). Two hundred and fifty-one simulations were run encompassing several dust storms occurring in April 2003. Wind velocity vectors were compared between the model and field data at three heights for six locations and were found to correlate well for a majority of the situations suggesting that the flow patterns are consistent throughout the domain. In particular, good agreement was found for wind speeds at 0.75\ m, the height for which the model was tuned. However, it overestimated velocities at 1.5\ m (10\%) and 3.15\ m (13\%). Generally, the model successfully identified locations of the highest wind velocities and wind stresses, predominately found in {\textquotedblleft}streets{\textquotedblright} aligned with the driving wind, and locations of wake flow downwind of mesquite bushes where there was separation flow or otherwise shelter from the wind.

}, keywords = {aeolian processes, roughness elements, aeolian processes, vegetation effects, aeolian processes, wind erosion, aeolian processes, wind-transported dust, article, Chihuahuan Desert, desert vegetation, journal, mesquite, model, air flow patterns, model, QUIC, NPP sites, sand transport, wind modeling, wind steering}, doi = {10.1007/s10652-005-6021-8}, url = {files/bibliography/JRN00448.pdf}, author = {Bowker, George E. and D. E. Gillette and Gilles Bergametti and B{\'e}atrice Marticorena} } @article {50429, title = {Mapping Shrub Abundance in Desert Grasslands Using Geometric-Optical Modeling and Multiangle Remote Sensing with CHRIS/Proba}, journal = {Remote Sensing of Environment}, volume = {104}, year = {2006}, month = {August 2006}, pages = {62-73}, abstract = {

This work examines the application of a geometric-optical canopy reflectance model to provide measures of woody shrub abundance in desert grasslands at the landscape scale. The approach is through inversion of the non-linear simple geometric model (SGM) against 631 nm multi-angle reflectance data from the Compact High Resolution Imaging Spectrometer (CHRIS) flown on the European Space Agency\&$\#$39;s Project for On-Board Autonomy (Proba) satellite. Separation of background and upper canopy contributions was effected by a linear scaling of the parameters of the Walthall bidirectional reflectance distribution function model with the weights of a kernel-driven model. The relationship was calibrated against a small number of sample locations with highly contrasting background/upper canopy configurations, before application over an area of about 25 square kilometers. The results show that with some assumptions, the multi-angle remote sensing signal from CHRIS/Proba can be explained in terms of a combined soil-understory background response and woody shrub cover and exploited to map this important structural attribute of desert grasslands.

}, keywords = {canopy reflectance, CHRIS, geometric-optical modeling, journal, journal article, mapping, modeling, multiangle remote sensing, PROBA, semi-arid environments}, doi = {10.1016/j.rse.2006.04.022}, url = {/files/bibliography/06-031.pdf}, author = {M. Chopping and L. Su and Andrea S. Laliberte and A. Rango and Debra C. Peters and Kollikkathara, N.} } @article {50428, title = {Mapping woody plant cover in desert grasslands using canopy reflectance modeling and MISR data}, journal = {Geophysical Research Letters}, volume = {33}, number = {L17402}, year = {2006}, month = {September 2006}, pages = {1-5}, abstract = {

A simplified geometric-optical model (SGM) was inverted using red band reflectance data acquired at 275 m in nine viewing angles from the Multiangle Imaging SpectroRadiometer (MISR) flown on NASA\’s Terra satellite, to provide estimates of fractional woody plant cover for large areas (over 3519 km2) in parts of the Chihuahuan Desert in New Mexico, USA. The use of the model in these semi-arid environments was enabled by the derivation of a priori estimates of the soil/understory background reflectance response. This was made possible by determining relationships between the kernel weights from a LiSparse-RossThin model adjusted against the same MISR data \– together with spectral reflectance data derived from MISR\’s nadir-viewing camera \– and the parameters of the Walthall model used to represent the background. Spatial distributions of retrieved fractional woody plant cover match those of \% tree cover in the global MODIS Vegetation Continuous Fields product but also include shrubs. Good relationships wereobtained with fractional shrub cover measured in pastures in the USDA, ARS Jornada Experimental Range but tree cover in higher elevation and riparian zones was dramatically overestimated as a result of the fixing of crown height and shape parameters.

}, keywords = {grasslands, MISR, woody plant}, doi = {10.1029/2006GL027148}, url = {/files/bibliography/06-040.pdf}, author = {M. Chopping and L. Su and Andrea S. Laliberte and A. Rango and Debra C. Peters and J. V. Martonchik} } @conference {50430, title = {A Multi-Angle Approach to Mapping Forest and Shrub Canopy Structure in the Southwestern United States}, booktitle = {NASA Biodiversity and Terrestrail Ecosystem Joint Workshop}, year = {2006}, month = {August 21-25, 20}, abstract = {Red wavelength data from NASA{\textquoteright}s Multi-angle Imaging SpectroRadiometer (MISR) acquired at a nominal 275 m and in nine viewing directions were used to invert a simple geometric-optical (GO) model to retrieve canopy structure parameters over parts of S.E. Arizona and S. New Mexico (>159,556 km2). This area encompasses desert grassland, often with woody shrub encroachment; riparian woodland; and upland forest. The combined soil and understory signal -- represented by the Walthall model -- was estimated a priori using regression relationships with MISR nadir data and the red band isotropic, geometric, and volume scattering kernel weights of the LiSparse-RossThin semi-empirical, kernel-driven bidirectional reflectance distribution function model, using measurements extracted from Ikonos panchromatic imagery over 19 locations in a grass-shrub transition zone with contrasting upper/lower canopy configurations. The GO model was adjusted using the Praxis minimization algorithm and the merit function min(|RSME|), with no constraints. Distributions of crown cover and mean canopy height for forested areas show good matches with maps from the USDA Forest Service developed from field survey as part of the Forest Inventory Analysis (FIA). Within upland forest, the mean canopy height map shows a better match with the corresponding FIA map than the cover map. Some areas with known shrub cover are predicted to have low or no woody plant cover, indicating a need to adjust the background calibration. Retrievals are very rapid almost 3 million inversions were completed in < 15 minutes allowing application of this method over very large areas.}, keywords = {MISR, multi-angle, red wavelength, shrub canopy, southwestern United States}, author = {M. Chopping and L. Su and Andrea S. Laliberte and A. Rango and Moisen, G. and J. V. Martonchik} } @article {50442, title = {Mesquite recruitment in the Chihuahuan Desert: historic and prehistoric patterns with long-term impacts}, journal = {Journal of Arid Environments}, volume = {65}, number = {2}, year = {2006}, month = {April 1, 2006}, pages = {285-295}, abstract = {Mesquite (Prosopis glandulosa) has increased in dominance over large areas of the Chihuahuan Desert, chiefly at the expense of once expansive desert grasslands. Excessive grazing and seed dissemination by livestock are often cited as the cause of this transition. We propose an alternate hypothesis that expansion of mesquite is not simply due to cause and effect relationships during recent history; rather, mesquite expansion is a result of a series of cause and effect relationships that transpired over a much longer timeframe (centuries). We assert that mesquite expansion may have ultimately occurred in the absence of widespread livestock grazing during the last 130 years because of removal of barriers to mesquite expansion created by Pleistocene megafauna and indigenous peoples. We explore factors that attenuate or intensify mesquite expansion and examine how a series of fine=scale, but temporally seminal, events can propagate across multiple scales. Furthermore, we examine the relevance of this hypothesis for present day remediation of shrub-dominated grasslands and conclude that knowledge of historic and prehistoric events and processes are essential to effectively manage landscapes. http://www.sciencedirect.com/science?_ob=MImg\&_imagekey=B6WH9-4HSY4WS-3-5\&_cdi=6845\&_user=1496926\&_orig=browse\&_coverDate=04\%2F30\%2F2006\&_sk=999349997\&view=c\&wchp=dGLbVtz-zSkWW\&md5=a516e16003fd57a18d1e636650b3d2eb\&ie=/sdarticle.pdf}, keywords = {historic legacy, invasive species, landscape history, prosopis glandulosa, seed dispersal}, url = {/files/bibliography/06-001.pdf}, author = {E.L. Fredrickson and Richard E. Estell and Andrea S. Laliberte and D.M. Anderson} } @article {50456, title = {Monitoring ecological processes for restoration projects}, journal = {Journal of Nature Conservation}, volume = {14}, number = {3-4}, year = {2006}, month = {September 2006}, pages = {161-171}, abstract = {Restoration of ecological processes is key to restoring the capacity of ecosystems to support social, economic, cultural and aesthetic values. The sustainability of the restored system also depends on processes associated with carbon, nutrient and hydrologic cycles, yet most restoration monitoring is limited to plant community composition. Our research has shown that short-term plant composition monitoring is a necessary but insufficient predictor of long-term restoration success. Long-term (up to 75 years) studies in the western United States show that short-term monitoring of plant community composition alone incorrectly predicted the failure of treatments that were ultimately successful, and the success of treatments that ultimately failed. We propose that vegetation composition monitoring be combined with one or more ecological process indicators reflecting changes in three fundamental ecosystem attributes on which restoration success depends: soil and site stability, hydrologic function and biotic integrity. These simple, rapid, plot-level indicators reflect changes in resource redistribution and vegetation structure. We include a case study involving restoration of mixed grass prairie on mineland in the west-central United States.}, keywords = {ecosystem services, erosion, indicators, landscape, monitoring, restoration, runoff, spatial pattern, spatial variability}, url = {/files/bibliography/06-032.pdf}, author = {Jeffrey E. Herrick and G.E. Schuman and A. Rango} } @article {50480, title = {Multiscale controls on and consequences of aeolian processes in landscape change in arid and semi-arid environments}, journal = {Journal of Arid Environments}, volume = {65}, year = {2006}, month = {April 1, 2006}, pages = {253-275}, abstract = {Aeolian processes are tightly linked to soil and vegetation change in deserts at multiple spatial and temporal scales. Wind influences patterns of vegetation and soil within the landscape, while these patterns control wind erosion at patch to landscape scales. Aggregated at larger scales, patterns in soil and vegetation distributions influence global distributions of dust and its biogeochemical impacts. Understanding the controls on aeolian processes is, therefore, important not only in understanding the biogeochemistry and land cover patterns in dryland environments but also in understanding global land cover, climate, and biogeochemistry. These relationships are poorly understood, particularly for structurally complex plant communities such as shrub-invaded grasslands. The objective of this paper is to review the controls on aeolian processes and their consequences at plant-interspace, patch-landscape, and regional-global scales. Based on this review, we define the requirements for a cross-scale model of wind erosion in structurally complex arid and semi-arid ecosystems. http://www.sciencedirect.com/science?_ob=MImg\&_imagekey=B6WH9-4H1004J-1-1N\&_cdi=6845\&_user=1496926\&_orig=browse\&_coverDate=04\%2F30\%2F2006\&_sk=999349997\&view=c\&wchp=dGLbVtb-zSkWA\&md5=e74666463d89e6fd5315d4fde2958934\&ie=/sdarticle.pdf}, keywords = {aeolian processes, desertification, dust emission, landscape change, wind erosion}, url = {/files/bibliography/06-010.pdf}, author = {Gregory S. Okin and D. E. Gillette and Jeffrey E. Herrick} } @inbook {50498, title = {Modeling the unique attributes of aridland ecosystems: Lessons from the Jornada Basin}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {321-353}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {16}, address = {New York, NY}, abstract = {The Jornada Basin is typical of aridland ecosystems of the southwestern United States and many other regions of the globe: it is water-limited with low annual net primary production (ANPP) and low-standing crop (Szarek 1979; Ludwig 1987). Yet, paradoxically, aridland ecosystems are structurally and functionally quite complex, exhibiting a remarkable range of species compositions and system behaviors. This can be attributed, in part, to the presence of complex topography and landscape physiography which, when combined with extreme variability in precipitation, produces striking spatial and temporal heterogeneity in the availability of essential limiting resources such as water and mineral nutrients.}, keywords = {aridland, ecosystems, paradixically, production, water-limited}, url = {/files/bibliography/06-067.pdf}, author = {J. F. Reynolds and P. R. Kemp and Ogle, K. and Roberto J. Fern{\'a}ndez and Q. Gao and Jianguo Wu}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @article {50505, title = {Multi-scale temporal variation in water availability: implications for vegetation dynamics in arid and semi-arid ecosystems}, journal = {Journal of Arid Environments}, volume = {65}, number = {2}, year = {2006}, month = {04/2006}, pages = {219-234}, chapter = {219}, abstract = {

The objective of this paper is to illustrate the importance of variation in water availability to temporal variation in vegetation dynamics. We hypothesize that fine-scale pulses of precipitation interact with longer-scale variation in climate and weather to generate temporal variation in plant community composition. Arid and semiarid regions exhibit a high degree of temporal variability in water availability as a result of variation in climate and weather at multiple scales and vegetation-soil water feedbacks. The scales of variation include: shifting climate regimes over centuries and decades, inter-annual variation in weather patterns, seasonal differences in winter and summer precipitation, and within-season variability in precipitation frequency and magnitude. In arid and semiarid regions pulses of rainfall are separated by intervening dry periods of variable lengths. This results in fluctuating availability of water that limits plant production and controls other ecological processes, such as rates of nutrient cycling. In many semiarid and arid systems, temporal variation in water availability may create positive feedbacks that facilitate encroachment of C3 woody plant species into areas formerly dominated by C4 grasses. Our ability to predict these complex shifts in vegetation composition may be improved by including temporal variation in climate, weather, and ecosystem processes.

}, keywords = {variation, vegetation dynamics, water availabililty}, doi = {10.1016/j.jaridenv.2005.06.023}, url = {/files/bibliography/06-004.pdf}, author = {K. A. Snyder and S. Tartowski} } @article {50523, title = {Multi-scale factors and long-term responses of Chihuahuan Desert grasses to drought}, journal = {Landscape Ecology}, volume = {21}, number = {8}, year = {2006}, note = {//USDA//LTER IV//entered 7/12/2006; updated 10/16/2006}, month = {2006}, pages = {1217-1231}, chapter = {1217}, abstract = {

Factors with variation at broad (e.g., climate) and fine scales (e.g., soil texture) that influence local processes at the plant scale (e.g., competition) have often been used to infer controls on spatial patterns and temporal trends in vegetation. However, these factors can be insufficient to explain spatial and temporal variation in grass cover for arid and semiarid grasslands during an extreme drought that promotes woody plant encroachment. Transport of materials among patches may also be important to this variation. We used long-term cover data (1915\–2001) combined with recently collected field data and spatial databases from a site in the northern Chihuahuan Desert to assess temporal trends in cover and the relative importance of factors at three scales (plant, patch, landscape unit) in explaining spatial variation in grass cover. We examined cover of five important grass species from two topographic positions before, during, and after the extreme drought of the 1950s. Our results show that dynamics before, during, and after the drought varied by species rather than by topographic position. Different factors were related to cover of each species in each time period. Factors at the landscape unit scale (rainfall, stocking rate) were related to grass cover in the pre- and post-drought periods whereas only the plant-scale factor of soil texture was significantly related to cover of two upland species during the drought. Patch-scale factors associated with the redistribution of water (microtopography) were important for different species in the pre- and post-drought period. Another patch-scale factor, distance from historic shrub populations, was important to the persistence of the dominant grass in uplands (Bouteloua eriopoda) through time. Our results suggest the importance of local processes during the drought, and transport processes before and after the drought with different relationships for different species. Disentangling the relative importance of factors at different spatial scales to spatial patterns and long-term trends in grass cover can provide new insights into the key processes driving these historic patterns, and can be used to improve forecasts of vegetation change in arid and semiarid areas.

}, keywords = {arid grasslands, desertification, drought, grazing, perennial grasses, transport processes}, doi = {10.1007/s10980-006-0025-8}, url = {/files/bibliography/06-034.pdf}, author = {Jin Yao and Debra C. Peters and Kris Havstad and Gibbens, Robert P. and Jeffrey E. Herrick} } @conference {50525, title = {The microscopic identification of vertically transferred symbiotic fungi intrinsically integrated with cells, tissues, and organs of host plants}, booktitle = {Mycological Society of America and Japan}, year = {2005}, month = {July 30-August 5}, address = {Hilo, Hawaii}, abstract = {Dual-staining methodology and analysis with light microscopy and scanning electron microscopy were used to determine the nature and extent of symbiotic fungi with native desert grasses shrubs. Trypan blue, which targets fungal chitin, and Sudan IV, which targets lipid bodies attached to fungal structures, were used to stain cleared roots and leaves. Trypan blue revealed a densely stained fungal network bound to the plasmalema of meristematic cells that were transferred to cells in culture, tissues, and all plant organs. Fungal structures were atypical and were substantially different than commonly observed fungal structures, such as hyphae, spores, etc. Fungal associations with meristems cells facilitate their distribution and vertical transfer to all parts of the plant, seed, and succeeding generations. Significant are fungal associations with vascular tissue, photosynthetic cells, and the stomatal complex and suggests significant plant-fungus interactions within these critical plant cells.}, keywords = {microscopic identification, symbiotic fungi, vertically transferred}, author = {Aaltonen, R.E. and J.R. Barrow and M.E. Lucero and P. Osuna-Avila and I. Reyes-Vera} } @conference {50538, title = {Microbial crust CO2 response to precipitation on the Jornada Experimental Range}, booktitle = {Ecological Society of America, 90th Annual Meeting}, year = {2005}, month = {August 7-12, 200}, pages = {91}, address = {Montreal, Quebec, Canada}, abstract = {Rainfall in deserts occurs in discrete events or pulses. The frequency and magnitude of precipitation pulses may differentially drive ecosystem components, such as soil microbes, plants, and microbial crusts. As significant components of desert ecosystems, microbial crusts are photosynthetic communities of lichen, bacteria, cyanobacteria, and fungi. On the Jornada Experimental Range in southern New Mexico, rainfall addition was used to manipulate the frequency and magnitude of rain events. Plots either received small (5mm) weekly pulses, large (20mm) monthly pulses, or ambient conditions (no additional rainfall). Crust CO2 exchange was measured two days after all plots received water treatments. Measurements were made prior to and after addition of 2mm of water, to measure CO2 flux in the native state and in moist conditions with stimulated activity, respectively. Prior to 2mm of water application, the dominant process was respiration on the control and monthly plots, while photosynthesis was the dominant process on the weekly plots. After the 2mm water application, all three treatments showed a photosynthetic response, with the weekly-pulsed plots showing the greatest response. Crusts that received more frequent, small events contributed more to ecosystem carbon gain than crusts that received larger, infrequent events or that experienced ambient conditions.}, keywords = {crust, microbial, precipitation, rainfall}, author = {Cable, J.M. and K. A. Snyder and Barron-Gafford, G. and Cable, William L. and Alfredo Huete and T. Huxman} } @conference {50541, title = {Modeling aeolian processes in the context of desertification}, booktitle = {20th Annual Symposium of the U.S. Regional Chapter of the International Association for Landscape Ecology}, year = {2005}, note = {poster presentation}, month = {03/2005}, pages = {61}, address = {Syracuse, NY}, abstract = {

Conversions from grasslands to shrublands have occurred throughout arid and semiarid regions globally over the past several centuries. Although a number of factors have been implicated as drivers of this conversion (e.g., grazing by livestock, drought, climate change), the key drivers responsible for vegetation change in any particular location are controversial. This controversy is due in large part to the large spatial variation in shrub invasion success through time. At the Jornada Experimental Range in southern New Mexico, we are taking a multi-scale approach to understanding and forecasting landscape scale dynamics associated with these desertification processes. As part of our approach, we are developing a spatially interactive model that simulates interactions and feedbacks between the vegetation, soil properties, and aeolian transport to explain and forecast vegetation dynamics at multiple spatial scales.\  Dynamic vegetation patches vary in size and composition that affect fetch and hence erosion and deposition of soil particles by wind. Wind speed data is given using a Weibull distribution derived from empirical data. Preliminary results show that aeolian transport is a key driver of conversions from grasslands to shrublands that depends on spatial characteristics of soil texture and vegetation.

}, keywords = {aeolian, conversions, desertification, modeling, multi-scale, shrublands, simulation}, author = {J.D. Daues and Debra C. Peters and Daues, G.} } @article {50543, title = {Mesquite (Prosopis glandulosa) germination and survival in black-grama (Bouteloua eriopoda) grassland: relations between microsite and heteromyid rodent (Dipodomys spp.) impact}, journal = {Journal of Arid Environments}, volume = {62}, number = {4}, year = {2005}, month = {June 1, 2005}, pages = {541-554}, abstract = {

We conducted experiments to examine microsite and rodent influence on mesquite (Prosopis glandulosa) germination and survival in Chihuahuan Desert black-grama (Bouteloua eriopoda) grassland. Simulated caches with mesquite seeds were placed in undisturbed grassland, burned grassland patches with reduced grass cover, and on the periphery of kangaroo rat mounds. Rodent access to cached seeds was controlled by covering half of the caches with mesh domes. Kangaroo rats destroyed dung pats containing scarified mesquite seeds and excavated all seeds in simulated caches during a year in which no grasses or forbs set seed. Germination was the highest in unburned grassland, but over-winter survival was only observed across experiments in burned grassland microsites. A large proportion of seed caches were excavated (1.1\–5.5\% of the rodent-excluded caches and between 15.6\% and 21.1\% of the control caches). There were seasonal differences in numbers of emergent seedlings, with a peak in September 2002 following late summer rains. There were no significant differences in numbers of germinants in burned and unburned grassland microsites, but significantly fewer mesquite seeds germinated on banner-tail kangaroo rat mounds. Caches excavated by rodents yielded 46.6\% of germinants. This study suggests that scarification of mesquite seeds is not necessary for germination and heteromyid rodents may be responsible for increased mesquite density in grasslands with some mature mesquite plants. The data also suggest that competition between mesquite seedlings and grasses in black-grama grassland is weak because of the physical characteristics of this system.

}, keywords = {germination, mesquite, microsite, rodent, survival}, doi = {10.1016/j.jaridenv.2005.01.012}, url = {/files/bibliography/05-004.pdf}, author = {B.D. Duval and E. Jackson and Walter G. Whitford} } @book {50559, title = {Monitoring Manual for Grassland, Shrubland and Savanna Ecosystems}, volume = {II}, year = {2005}, month = {2005}, pages = {200}, publisher = {University of Arizona Press - Distributor}, organization = {University of Arizona Press - Distributor}, address = {Tucson, AZ}, abstract = {This two-volume document is intended to assist a wide range of users, including technicians (data collectors), field crew leaders, ranchers and landowners, land managers, rangeland professionals, and researchers. Volume II provides more detailed guidance on monitoring program design, data analysis and interpretation. It also includes a number of supplementary methods.Monitoring is part of a broader process in which we use data to test and refine management decisions. Monitoring data allow the collective knowledge of scientists and land managers to be applied to improve resource management. Monitoring is designed to support a diverse set of goals required by various societal interests. The monitoring procedures described in this manual provide data on three key attributes of landscape and ecosystem sustainability: soil and site stability, hydrologic function, and biotic integrity. These data provide the foundation for assessing and evaluating the degree to which societal goals and/or values are being met by current landscape management. They also provide the basis for management options that meet specific goals. http://usda-ars.nmsu.edu/monit_assess/PDF_files/Volume_II.pdf.}, keywords = {ecosystem, grassland, management, monitoring, monitoring manual, savanna, shrubland}, url = {/files/bibliography/05-008.pdf}, author = {Jeffrey E. Herrick and Justin Van Zee and Kris Havstad and Laura M. Burkett and Walter G. Whitford} } @book {50561, title = {Monitoring Manual for Grassland, Shrubland and Savanna Ecosystems, Volume I: Quick Start}, year = {2005}, month = {January 1, 2005}, pages = {36}, publisher = {The University of Arizona Press}, organization = {The University of Arizona Press}, address = {Tucson, Arizona}, abstract = {

This manual describes how to monitor three rangeland attributes: soil and site stability, watershed function and biotic integrity. Nearly everything we value about rangelands depends on these attributes. Monitoring these three attributes is like monitoring the foundation of our rangeland ecosystems. The measurements used to monitor these attributes also can be used to generate indicators relevant to specific management objectives, such as maintaining wildlife habitat, biodiversity conservation or producing forage. Quick Start (Vol.I) includes basic methods and instructions for establishing photo points and completing four basic mesurements.

}, keywords = {grassland, monitoring manual, savanna, shrubland}, url = {/files/bibliography/05-003.pdf}, author = {Jeffrey E. Herrick and Justin Van Zee and Kris Havstad and Laura M. Burkett and Walter G. Whitford} } @article {50570, title = {Mineralogical distinctions of carbonates in desert soils}, journal = {Soil Science Society of America Journal}, volume = {69}, year = {2005}, note = {//NONE//LTER IV//Added 7/29/2005, Updated 5/15/2006.}, month = {2005}, pages = {1773-1781}, abstract = {

Soil carbonate-C is a large pool of C and, in desert environments, is the dominant type of C stored in soil. To more fully understand the global C cycle and the role of soil in C sequestration, it is important to recognize how C enters and leaves the carbonate pool, as well as identify the forms of carbonate that exist in the soil. In the Desert Project in southern New Mexico, soils formed in limestone and igneous (mostly quartz monzonite and some rhyolite) parent materials lie adjacent to each other, with climate, vegetation, topography, age, and, to a large extent, dust deposition constant across the soils of both parent materials. The purpose of this study was to determine if X-ray diffractometry (XRD) can mineralogically identify the size fraction in which pedogenic carbonate occurs and discern differences among (i) pedogenic carbonate formed in limestone parent material, (ii) pedogenic carbonate formed in igneous parent material, and (iii) soil carbonate in the form of detrital limestone. The diffractograms revealed that the size fractions in which pedogenic carbonate occurs in a dolostone residuum are fine sand, silt, and clay. X-ray diffraction could not discern differences in soil carbonate because calcite was the only carbonate mineral present in the samples of pedogenic carbonate formed in limestone parent material, pedogenic carbonate formed in igneous parent material and detrital limestone. Excepting the d-spacing associated with a minor peak, statistical analysis found no signifi- cant differences in d-spacings among the three types of soil carbonate. However, each of the three types of soil carbonate revealed significant differences in d-spacings relative to those of the calcite reference. While XRD mineralogically revealed the size distribution of pedogenic carbonate formed in a dolostone residuum, for the purpose of C sequestration, XRD was unable to distinguish the three soil carbonate types.

}, keywords = {article, carbon storage, soil, carbon, inorganic sequestration, carbonate, geogenic, journal, soil, soil, calcium carbonate, soil, carbonate, soil, pedogenic carbonates, techniques, X-ray diffractometry, techniques, XRD}, url = {files/bibliography/JRN00429.pdf}, author = {R. A. Kraimer and Curtis H. Monger and R.L. Steiner} } @proceedings {50571, title = {Multi-scale, Objected-oriented analysis of Quickbird Imagery for Determining Percent Cover in Arid Land Vegetation}, year = {2005}, month = {October 4-6, 200}, pages = {CDROM}, address = {Weslaco, TX}, abstract = {Efforts to remotely sense arid land vegetation are often encumbered by high reflectance of the soil background, mixtures of green and senescent grasses, and the prevalence of shrubs in grasslands. These issues make it difficult to classify vegetation or estimate percent vegetation cover. Objectives of this study were to derive estimates of percent cover for several vegetation classes in a 1200 ha pasture at the USDA, Agricultural Research Service{\textquoteright}s Jornada Experimental Range. A stratified random sample approach was used to determine percent cover for 322 field plots. A QuickBird satellite image was segmented at different scales which resulted in image objects for which a multitude of spectral, spatial, and texture characteristics were extracted. We used regression trees to develop a rule base for image classification and performed discrete and fuzzy accuracy assessments. For classes with discrete boundaries map accuracy was 73\%, while accuracy values ranged from 81-86\% using a 2.5-5\% cover boundary around each class. This object-oriented multi-scale approach allowed us to extract shrubs at a fine scale and determine percent cover values for the shrub-interspace at a coarser scale. In addition, shrub density and percent cover for different grass species could be extracted using this method. The regression tree was an excellent tool for reducing the number of input variables derived from the image. Future research will include refining the predictive ability of the decision tree and determining the possibility of applying this model to other locations and/or to other scales.}, keywords = {object-oriented}, url = {/files/bibliography/05-055Proc.pdf}, author = {Andrea S. Laliberte and A. Rango and E.L. Fredrickson} } @article {50583, title = {Micro-Patch and community scale spatial distribution of herbaceous cover in a grazed eucalypt woodland}, journal = {Journal of Arid Environments}, volume = {60}, number = {(3)}, year = {2005}, month = {July 2, 2005}, pages = {509-530}, abstract = {This study described changes in spatial distribution of herbaceous cover in experimental paddocks in a eucalypt woodland of northern Australia after 5 years of different grazing pressures and drought. Herbaceous cover was irregularly distributed, with high cover zones in distinct bands across slopes on paddocks in stable and degrading condition, and irregular patches in a degraded paddock. Size and density of these zones declined with paddock condition, as native perennial tussock grasses were lost and replaced by an exotic stoloniferous grass. Describing disturbance responses of herbaceous cover in this community requires sampling at multiple spatial scales. http://www.sciencedirect.com/science?_ob=MImg\&_imagekey=B6WH9-4D1DD3K-2-1\&_cdi=6845\&_user=1496926\&_orig=browse\&_coverDate=02\%2F28\%2F2005\&_sk=999399996\&view=c\&wchp=dGLbVlb-zSkWb\&md5=152f301190b397ad33d1092399d204e2\&ie=/sdarticle.pdf}, keywords = {Australia, eucalypt, herbaceous, spatial, woodland}, url = {/files/bibliography/05-007.pdf}, author = {Northup, B.K. and Dias, C. and Joel R. Brown and Skelly, C.} } @conference {50601, title = {Multivariate 3-way Data Analysis to Identify Specific Plants in the Diets of Free-Ranging Herbivores}, booktitle = {Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy}, year = {2005}, month = {February 26-Marc}, pages = {70}, address = {Orlando, FL}, abstract = {The issue of identifying specific plant species in the diets of free ranging herbivores in the local and global community is of much interest in the context of three-way analysis. The identification process was analyzed using chemometrics methods applied to the excitation emission fluorescence of a number of plant species. We were able to develop an integrated approach to perform tasks such as multidimensional analysis, process modeling and statistical process decomposition. A description is given to the advantages of combining several chemometrics tools (Parallel Factor Analysis (PARAFAC), multiway principal component analysis, PARAFAC II, and GRAM) and the principal benefits associated with each strategy for the elucidation of diet composition. Also a general overview of the principal achievements and limitations of the techniques used within the presented methodology is depicted. It is illustrated how three-way principal components analysis as the appropriate generalization of conventional principal component analysis may serve as a powerful method for classification of specific plant species in diets of free ranging herbivores using the excitation-emission matrices from fluorescence spectroscopy from different species. The factors found appear to correspond to the causal influences manipulated in the experiment, revealing their patterns of influence in all three ways of the data. Several generalizations of the parallel factor analysis model are currently under development, including ones that combine parallel factors with Tucker-like factor {\textquoteleft}interactions{\textquoteright}. In the research, necessary and sufficient conditions for global and local solutions to plant identification are being derived. The results of these investigations will be presented and the implications of the application of these data analysis tools for the identification of specific noxious weeds within the diets of free-ranging cattle will be discussed.}, keywords = {free-ranging, herbivores}, author = {Sisk, C.N. and Pezzotti, C. and S. Obeidat and G.D. Rayson and E.L. Fredrickson and Richard E. Estell and D.M. Anderson} } @conference {50603, title = {Multi-scale responses of carbon and water fluxes to magnitude and frequency of precipitation pulses in the Northern Chihuahuan desert}, booktitle = {Ecological Society of America, 90th Annual Meeting}, year = {2005}, month = {August 7-12, 200}, pages = {599}, address = {Montreal, Quebec, CANADA}, abstract = {Changes in the frequency and magnitude of precipitation may be as important as changes in total seasonal precipitation amounts, especially in water-limited environments. We manipulated both the frequency and magnitude of precipitation over two growing seasons in the northern part of the Chihuahuan desert at the Jornada Experimental Range. A 46\% increase relative to mean summer rainfall was applied at two different frequencies and magnitudes over twelve weeks during the summer growing season to plots containing both mesquite (Prosopis glandulosa) and black grama grass (Bouteloua eriopoda). Plots received either: ambient precipitation (controls), ambient plus frequent small (5-6 mm) rainfall events applied weekly, and ambient plus infrequent large (20-24 mm) events applied monthly. Fluxes of carbon and water were measured at different scales using static chambers and an IRGA. Isotopic partitioning of evapotranspiration (ET) fluxes indicated that the proportion of ET accounted for by mesquite transpiration increased in large infrequent rainfall treatments relative to small frequent rainfall treatments; however, mesquite was able to use water from both large and small magnitude rainfall treatments. Evapotranspiration flux in large chambers containing mesquite, grass and soil was higher in large infrequent watering treatments than in the other two treatments in August and September, but not July. However, increased uptake of CO2 was observed only in large infrequent watering treatments in August. In contrast to this, smaller chambers containing only grass and soil showed increased uptake of CO2 in both small frequent rainfall and large infrequent rainfall treatments. These data suggest that changes in the depth and duration of soil wetting in conjunction with the degree of mesquite encroachment may have important implications for carbon and water cycling.}, keywords = {carbon, Chihuahuan, fluxes, frequency, multi-scale, northern, precipitation, water}, author = {K. A. Snyder and Connie J. Maxwell and Cable, J.M.} } @conference {50619, title = {A moving virtual boundary (VB trademark)}, booktitle = {6th Symposium of the Natural Resources of the Chihuahuan Desert}, year = {2004}, month = {October 15, 2004}, pages = {Abstract p. 16}, address = {Alpine, Texas (Sul Ross State University)}, abstract = {Distributing free-ranging animals across a landscape to facilitate proper forage utilization is universally challenging to range livestock managers. By combining Global Positioning System (GPS) technology, Geographical Information System (GIS) methodology and a practical knowledge of animal behavior, we have developed a methodology for autonomously controlling free-ranging animals. Directional Virtual Fencing (DVF{\texttrademark}) uses programmable sensory cues administered at the proper time and in the correct location on the animal to keep animals within a Virtual Paddock (VP{\texttrademark}) delineated by a Virtual Boundary (VB{\texttrademark}). Using Arc GIS 9 Tracking Analyst software, the geospatial animal data were visually depicted to move within the VP as the north and south VB moved in tandem in time and space across the landscape. Being able to manage grazing pressure using DVF will provide Prescription Stocking (RxS{\texttrademark}) without the challenges wire fencing places on conventional rotational stocking strategies.}, keywords = {DVF, forage utilization, free-ranging animals, GIS, GPS, virtual boundary, virtual fencing}, author = {D.M. Anderson and E.L. Fredrickson and Kris Havstad and B. Nolen and Nayak, P. and C.S. Hale} } @conference {50636, title = {Managing land using ecological processes}, booktitle = {3rd Annual Conference, Quivira Coalition}, year = {2004}, month = {January 15-17, 2}, pages = {18-19}, address = {Albuquerque, NM}, abstract = {Ranching in nature{\textquoteright}s image requires not only an understanding of what ecological processes may be important, but also a well-developed working knowledge of how those processes occur in space and time. While the scientific and ranching communities have devoted much attention to describing and managing important ecological processes like energy flow, nutrient transformation and cycling, water cycling, seed dispersal, etc., we have not spent a great deal of effort putting these processes into a management context with clear links to on-the-ground decision making. In this session, we will cover three important concepts that serve as a framework for interpreting information about ecological processes and suggest a means of organizing and, more importantly, testing whether management actions are having the desired effects. First, we will discuss the importance of variability in space and time when interpreting general or site-specific information for management decisions. For instance, rainfall infiltration rate is a good indicator of plant community and soil health. However, the rate of infiltration can vary dramatically within a paddock, within a plant community or even around an individual plant even though the entire area is subject to the same management and may be described as the same soil or the same ecological site. Knowing where and when to gather information about ecological processes is a critical component of management planning and effective monitoring. Second, the concepts of resistance and resilience are fundamental to interpreting ecosystem behavior and making management decisions designed to achieve goals and objectives. Resistance is the degree of disturbance (for instance, grazing) a plant community or soil can tolerate before it changes to another state. Resilience is the time it takes for a plant community or soil to return to its original state when the disturbance (for example, drought) is suspended. A qualitative understanding of resistance and resilience for specific sites is fundamental for making effective decisions about management and interpreting monitoring data. Finally, we will discuss the importance of ecological thresholds in managing grazing lands. Ecological thresholds can be viewed as critical periods in time when plant community and soil processes undergo significant and persistent changes in response to particular management or natural factors. Such changes are common when resistance and resilience are compromised. Once processes have changed and a new state is indicated, there is a very low probability that the community/soil will return to its original state without costly management intervention. Management models and monitoring systems must be designed with ecological thresholds in mind. The concepts of spatial and temporal variability, ecosystem resistance and resilience, and ecological thresholds can be combined to interpret information about ecological patterns and processes occurring in a ranch. While these concepts are general, the complexity of landscapes precludes the development of general, management-oriented mathematical models of rangeland behavior. Site-specific application of the concepts is a key component of effective and successful range management.}, author = {Brandon T Bestelmeyer and Joel R. Brown and Kris Havstad and S. Tartowski} } @conference {50639, title = {A manager{\textquoteright}s dilemma: Making logical decisions at the local scale}, booktitle = {89th Annual Meeting, Ecological Society of America}, year = {2004}, month = {2004}, pages = {Abstract p. 66}, address = {Portland, OR}, abstract = {General principles for land management within a region are usually derived from the extrapolation of nontemporally replicated, plot-scale experiments. To successfully implement recommendations, land managers ultimately must restrict the spatial extent of action to match available resources. Overextending scarce resources, whether financial or intellectual, usually results in failure at best, and at worst can initiate catastrophic degrading processes. Realistically, the extent at which managerial control can be exercised seldom exceeds 10 km2, a scale at which factors external to site-specific applications have as much influence on outcomes as internal factors. It is virtually impossible to adapt concepts, principles or guidelines consistently to site-specific application without a well developed understanding of spatial and temporal variability in driving factors. Improving chances of management success requires a combination of deductive (applying general principles at a site specific level) and inductive (using local observations to seek explanations) reasoning. Managers often rely on general assertions regarding the dominant factors driving change across a region because there is little guidance available to understand scale dependence, factor interactions and variability and their consequences for management decisions. We suggest that institutional management guidance for making site-specific decisions is inadequate unless we also develop a framework for testing local observations against multiple, scale-dependent, competing hypotheses to predict responses.}, keywords = {applications, factors, land management, local scale, site-specific}, author = {Joel R. Brown and Brandon T Bestelmeyer and Jeffrey E. Herrick} } @article {50640, title = {Monitoring to detect change on rangelands: physical, social, and economic/policy drivers}, journal = {African Journal of Range and Forage Science}, volume = {21}, number = {2}, year = {2004}, month = {October 1, 2004}, pages = {115-121}, abstract = {Environmental drivers are factors that cause measurable changes in properties of biological communities. Examples of drivers can include environmental factors, such as rainfall variability and available soil nitrogen; management factors, such as livestock grazing practices and prescribed burning; government factors, such as tax laws and environmental policies; and societal factors, such as attitudes regarding property rights and public values. It is difficult to identify the impact of specific drivers on specific properties at specific times since drivers seldom operate independently, at similar scales, or in isolation from other drivers. Impacts of some drivers, especially nonecological, may not be quantifiable. Yet, any interest in understanding how systems will respond to specific drivers, such as grazing management practices, requires monitoring of system dynamics and pertinent environmental drivers at appropriate scales. For example, risk assessments, adaptive management analyses, or management by hypothesis require understanding linkages between environmental drivers and various management options on ecological properties of managed systems. Any type of predictive management strategy for proposing future options would require an understanding of biological responses to environmental stressors. Though our abilities to generate accurate predictions are currently limited, conceptual models of system response to drivers are improving. Continued incorporation and refinement of understanding and monitoring effects and interactions of different drivers will contribute to improvements in these predictive capacities. It is important to remember we are developing monitoring systems for the future, as well as for today.}, keywords = {biological, communities, drivers, environmental, monitoring}, url = {http://www.ajol.info/viewissue.php?jid=3\&id=1619$\#$Articles}, author = {Joel R. Brown and Kris Havstad} } @article {50644, title = {Modeling the reflectance anisotropy of Chihuahuan Desert grass-shrub transition canopy-soil complexes}, journal = {International Journal of Remote Sensing}, volume = {25}, number = {14}, year = {2004}, month = {2004}, pages = {2725-2745}, abstract = {The goal of the research presented is to understand better the factors controlling the remotely sensed signal returned in the red wavelengths from grass-shrub transition canopy-soil complexes. The specific objectives were to evaluate the importance of the different elements (overstory, understory, soil) in the bi-directional reflectance distribution function (BRDF) and to explore the behavior of simple parametric and explicit scattering models with respect to observations. The first objective was approached by simulations using the Radiosity Graphics Method (RGM) with surface parameters provided by measurements of plant locations and dimensions surveyed over 25m plots. The second was approached through simulations of bi-directional reflectance by both the RGM and a Simplified Geometric Model (SGM). The simulated reflectance values were assessed against samples of the BRDF at a wavelength of 650nm acquired from the air at six view zenith angles and three solar zenith angles by a tilting, radiometrically-calibrated multispectral digital camera providing multi-angle observations (MAO). The results show that the understory of small forbs and sub-shrubs plays a very important role in determining the brightness and to some extent reflectance anisotropy of these landscapes. This is owing to the potential large number density of broom snakeweed and to a varying proportion of black grama grass and prone grass litter. Both of these components darken the scene. The SGM performed well measured against both the RGM and the MAO (r2 of 0.98 and 0.92 against the RGM and MAO, respectively). Both models underestimated reflectance by a small amount, less than 6\% over all angles, with both showing increasing divergence from the backcsattering into the forward-scattering direction.}, keywords = {BRDF, canopy-soil complexes, Chihuahuan Desert, grass-shrub transition, reflectance anisotropy, remote sensing, RGM, SGM}, url = {/files/bibliography/04-005.pdf}, author = {M. Chopping and L. Su and A. Rango and Connie J. Maxwell} } @proceedings {50645, title = {Multiangle data from CHRIS/Proba for determination of canopy structure in desert rangelands}, volume = {VII}, year = {2004}, month = {2004}, pages = {4742-4745}, abstract = { Multi-angle spectral radiance images from the Compact High-Resolution Imaging Spectrometer (CHRIS) on the European Space Agency\&$\#$39;s Proba satellite were acquired over desert grasslands in the USDA-ARS Jornada Experimental Range near Las Cruces, New Mexico, USA. The data were used to obtain multiangle ratio images and to effect spatial bidirectional reflectance distribution function (BRDF) model inversions. The results show that there is canopy 3-D structure information observable in ratio images but physical interpretation is difficult. Inversion of a simple, nonlinear model for three canopy parameters resulted in low root-mean-square error values. The difficulty of decomposing the effects of brightness and reflectance anisotropy (BRDF shape) in complex desert shrub landscapes with varying soil-understory characteristics was overcome by allowing linear scaling of the parameters of the soil-understory submodel as a function of near-nadir 631 nm reflectance. The retrieved parameter maps show a high spatial correlation between width and height but a different distribution for density. Examination of high-resolution panchromatic and multispectral imagery shows that there are strong relationships between the retrieved parameters and canopy characteristics although further validation is required.}, keywords = {canopy structure, CHRIS, desert rangelands, multiangle data, PROBA}, url = {/files/bibliography/04-033.pdf}, author = {M. Chopping and Andrea S. Laliberte and A. Rango} } @conference {50652, title = {Management effects on livestock use of landscapes: Protein supplementation}, booktitle = {89th Annual Meeting, Ecological Society of America}, year = {2004}, month = {August 1, 2004}, pages = {Abstract p. 166}, address = {Portland, OR}, abstract = {Over half of the Earth{\textquoteright}s land surface is grazed by livestock. The effects of livestock grazing on terrestrial ecosystems range from detrimental to beneficial depending on ecosystem attributes and livestock management. Understanding the ecological implications of livestock management decisions is central to successful human interactions with complex environments. For example, supplementing heifers with a 32\% protein supplement concentrated heifer movements in areas near water and supplementation points. Prior to supplementation, animal movements were dispersed throughout the pasture. While concentrated movements are at times desirable, they can also trigger undesirable ecosystem trajectories. As part of a larger goal to better understand the ecological impacts of livestock grazing, we designed a study to examine the effects of protein supplementation, a common management practice, on livestock use of landscapes. Thirty-six multiparous, lactating, Angus x Hereford cows were randomly assigned to one of three treatments: (1) control (CON), no supplementation, (2) supplementation each day at 0700 (AM) with 0.75 kg of a 32\% crude protein pellet, or (3) supplementation at 1300 (PM) each day with the same supplement. Fifteen days prior to the study, animals were allowed to become familiar with experimental procedures and the 2,425 ha study pasture described as Chihuahuan Desert grassland ecotype. Animals from each treatment were fitted with Lotek GPS collars and rotated into the study pasture for a period of 5 days for three rotations. Animal position was acquired every 5 minutes. Mean distance from water differed (P < .0001) across treatments (2.55, 2.09, and 1.53 km for CON, PM, and AM, respectively). Distance traveled per day also differed (P < .0001) across treatments (7.17, 7.20, and 7.96 km/day for CON, PM, and AM, respectively). The area encompassing daily activities (Jennrich-Turner estimate of home range) also differed (P < .0001; 4.3, 2.8, and 3.9 square km/day for CON, PM, and AM, respectively). Protein supplementation and timing of supplementation affect the spatial use of desert grasslands and is likely to have important ecological implications. Furthermore, research examining livestock impacts must do so with an understanding of the effects of management on livestock behavior.}, keywords = {ecological impacts, ecosystems, livestock, livestock behavior, livestock management, protein supplementation}, author = {E.L. Fredrickson and J. Koppa and Richard E. Estell and D.M. Anderson and Kris Havstad} } @conference {50653, title = {Mesquite recruitment: historic patterns with long-term impacts}, booktitle = {Sixth Symposium on the Natural Resources of the Chihuahuan Desert Region}, year = {2004}, month = {October 15, 2004}, pages = {24}, address = {Alpine, TX}, abstract = {Mesquite (Prosopis glandulosa Torrey) has increased in dominance over large areas of the Chihuahuan Desert, chiefly at the expense of once expansive desert grasslands. Excessive grazing and seed dissemination by livestock are often attributed as the cause of this transition. We propose an alternate hypothesis that expansion of mesquite is not due to simple cause and effect relationships, but rather a network of cause and effect relationships. We assert that mesquite expansion may have occurred even in the absence of the widespread livestock grazing occurring during the last 130 years. We then look at factors that attenuate or intensify mesquite expansion and how a series of small-scale but temporally seminal events propagate across multiple scales. Lastly, we examine how acceptance of this hypothesis, or its parts, might be useful in enhancing 21st century efforts focused on remediation of desert grasslands.}, keywords = {Chihuahuan Desert, excessive grazing, long-term impacts, mesquite, patterns, seed dissemination, small-scale events}, author = {E.L. Fredrickson and Laurie Abbott and D.M. Anderson and Richard E. Estell} } @conference {50677, title = {Making ecology relevant to sustainability: Trends, lessons, and challenges for stronger links between ecology, society, and policy}, booktitle = {89th Annual Meeting, Ecological Society of America}, year = {2004}, month = {August 1-6, 2004}, pages = {Abstract p. 271}, address = {Portland, OR}, abstract = {Rangeland degradation has become an environmental problem of enormous proportions worldwide and is commonly the result of unsustainable livestock production. Degradation threatens not only the ecological integrity of grasslands, shrublands, and savannas, but also the social and economic viability of pastoralist communities that depend on them. Rangeland ecology can provide much of the information necessary to assess, restore, and manage degraded rangeland, but implementing sustainable land use strategies will ultimately depend on integrating the ecological information with social, economic, and policy considerations. In this paper we discuss common challenges that arise in developing and implementing plans for sustainable rangeland use. We break these challenges down into categories of ecological, social, economic, and policy issues and present some important principles that can help promote the role of ecological information in resolving those issues. Within the field of rangeland ecology itself, we focus upon the utility of models for understanding degradation and the necessity of incorporating land restoration or rehabilitation into sustainable land-use strategies. In terms of the social challenges, we focus on the importance of pastoralist education and participation in the ecological aspects of sustainable land management, because of the importance of self-reliance to the long-term success of a project and also because traditional ecological knowledge may not always be adequate or relevant for lands that are degraded far beyond their historical condition. Economically, we explain how the ecological condition of rangelands can be directly linked to economic benefits for pastoralists, but also how perverse incentives can arise to disrupt that linkage. Finally, we discuss the role of local, national, and international policy in the promotion of sustainable land-use systems. We compare the effectiveness of grass-roots and top-down approaches to rangeland management programs and argue for greater involvement in policy advocacy by rangeland ecologists. We will illustrate these trends, lessons and challenges with summaries of global case studies.}, keywords = {challenges, ecology, lessons, policy, rangelands, society, sustainable land use, trends}, author = {King, E.G. and Roberts, M. and Jeffrey E. Herrick} } @proceedings {50681, title = {Mapping shrub encroachment from 1937-2003 in the Jornada Basin of southern New Mexico}, year = {2004}, month = {May 23-28, 2004}, pages = {Abstract No. 120}, address = {Denver, CO}, abstract = {Shrub encroachment into arid and semi-arid grass-dominated landscapes has been noted in many parts of the Southwestern United States. Although it is well known that shrubs have increased over time, we have little quantitative information related to the rate of vegetation change over a particular time period. Our objective was to use aerial photos to measure the rate of shrub advance which is influenced by outside factors such as persistent drought periods and, in turn, has a direct influence on changes in the water, carbon, and energy cycles of these arid lands. In the Jornada basin of southern New Mexico, shrub increase has been measured with various ground survey techniques extending back to 1858. Researchers at two rangeland research field stations, the Jornada Experimental Range (JER) (USDA-ARS) (783 km2) established in 1912 and the adjacent Chihuahuan Desert Rangeland Research Center (CDRRC) (New Mexico State University) (259 km2) established in 1927, have been attempting to remediate the shrub-invaded grasslands with a number of rangeland treatments since the early 1900s. Initially, manual and mechanical removal techniques were used along with experimentation with various chemicals and fire in certain pastures. Starting in the 1950s, herbicides were applied to many pastures through the 1970s. Herbicides were effective in controlling the shrub advance if used on a regular basis. Record keeping was not consistent, but it seems that herbicide treatments were applied to much of the basin where shrubs were present. This widespread use of herbicides has made it difficult to assess how rapidly the shrubs were invading grassland in the last 60+ years. According to CDRRC records, only Pasture 2 has not been treated with herbicides. We have chosen Pasture 2 to monitor the shrub advance unaffected by herbicide treatments since the mid 1930s when aerial photographs wereacquired over the Jornada basin for the first time. Since 1936, thirty-seven separate aerial photography missions have been flown over parts of JER/CDRRC. Recently, the area has been imaged with high resolution commercial satellites. We selected 11 aerial photos that covered the study area and had sufficient resolution for shrub detection. A QuickBird satellite image was used for the 2003 coverage of the area. All photos were scanned, georectified and resampled to a common resolution of 86 cm. For our analysis, we used an object-oriented classification approach. In a pixel-based classification, the difficulty with analyzing single band aerial photos is associated with the low spectral resolution. This makes it often impossible to differentiate shrubs from the background in different areas of the image. An object-oriented approach allows the user to apply locally different strategies for analysis. We used the fractal net evolution approach (FNEA), which is an object-oriented multi-scale image analysis method embedded in the software eCognition (Baatz and Schaepe 2000, Definiens 2003). The first step is a segmentation of the image based on 3 parameters: scale, color (spectral information) and shape, which segments the image into object primitives based on the chosen parameters. Classification is then performed using those objects rather than single pixels. The multiresolution segmentation approach allows for segmentation at different scales, which is used to construct a hierarchical network of image objects representing the image information in different spatial resolutions simultaneously. This allows for differentiation of individual shrubs on the lower level, and determination of different shrub density classes on a higher level. The classification is based on fuzzy logic theory combined with user-defined rules. Spectral, shape and statistical characteristics as well as relationships between linked levels of the image object primitives can be used to combine them into meaningful classes. The total area covered by individual shrubs in pasture 2 increased from 0.9\% in 1937 to 13.1\% in 2003. In 1960, shrub cover increased to 10.9\%, then decreased in 1967 before resuming a gradual increase until 2003. Most of the shrub cover increase occurred during and just after the 1951-1957 drought which is believed to be the most severe in the past 350 years. The high shrub cover in 1960 may be partially attributed to image quality. Although all images were resampled to the same pixel size, shrubs appeared larger and separate shrubs tended to merge together in the 1960 image. In the 2003 QuickBird image, shrubs appeared to be less defined, however, visual inspection confirmed that a larger proportion of small shrubs were captured. This is due to the larger bit depth (11 bits) in the QuickBird image compared to the 8 bit range in aerial photography. Due to limitations in pixel size, the smallest shrub we could classify was 0.74 m2 (1 pixel), although many of the small shrubs were not captured due to lack of contrast. Therefore, our shrub cover estimate is likely an underestimation of the actual shrub cover. In this Pasture 2 study area, the average rate of increase of shrub cover percentage is about 0.2\% per year over the 66 year period. More rapid increases are noted in specific years, such as after the 1951-1957 severe drought. Certain years illustrate that shrub cover can also decline. It is difficult to say if this is a real effect or one resulting from varying image quality. The object-oriented multi-scale image analysis method used in this study has several advantages over a pixel based classification approach when the goal is the extraction of relatively small objects such as shrubs from panchromatic aerial photos and high resolution satellite images. This method approximates the way humans interpret information visually from aerial photos, but has the advantage of an automated classification routine. Combining several scales of analysis in a hierarchical segmentation method is appropriate in an ecological sense. The difficulties we encountered were related to varying image qualities (resolution, contrast, sun angle) as well as separating image quality from ecological variations (moisture conditions, time of year). Nevertheless, historical photos provide an important record of shrub increase over time. This technique shows promise for evaluating shrub encroachment using historical aerial photography and high resolution satellite imagery.}, keywords = {drainage basin, Jornada Basin, mapping, New Mexico, shrub encroachment, snow cover}, author = {Andrea S. Laliberte and A. Rango} } @inbook {50696, title = {Modelling wind erosion and dust emission on vegetated surfaces}, booktitle = {Spatial Modeling of the Terrestrial Environment}, year = {2004}, note = {//USDA//LTER IV// Listed in LTER IV 2004 annual report}, month = {2004}, pages = {137-156 pp}, publisher = {Wiley, and Sons, Ltd}, organization = {Wiley, and Sons, Ltd}, abstract = {

Summary

This chapter contains sections titled:

}, keywords = {book, books, chapter, chapters, model, dust emission, model, wind erosion, report, reports, wind erosion, dust emission, wind erosion, modelling}, doi = {10.1002/0470094001.ch7}, author = {Gregory S. Okin and D. E. Gillette}, editor = {R. Kelly and Drake, N. A. and Barr, S. L. eds.} } @conference {50734, title = {A method of evaluating systemic colonization of leaves by dark septate fungal endophytes in Bouteloua eriopida (Torr.) Torr., a native grass in arid southwestern USA rangelands}, booktitle = {Fourth International Conference on Mycorrhizae}, year = {2003}, note = {Need page number; abstracts haven{\textquoteright}t been printed yet.}, month = {August 10-13, 20}, address = {Montreal, Canada}, abstract = {Dominant native grasses in arid southwestern USA rangelands are more extensively colonized by dark septate endophytic fungi than by conventional mycorrhizal fungi. A method was developed to determine the nature and extent of colonization of leaves of Bouteloua eriopida (Torr.) Torr. Photosynthetically active leaves were scraped with a scalpel to separate tissue layers, dual stained with trypan blue and Sudan IV, placed on a slide and analyzed at 1000X with differential interference microscopy. All leaf cells were colonized and internal fungal morphology was highly variable. Sudan IV stained lipid bodies associated with fungal protoplasts. Nonstained hyaline hyphae were also observed. As leaves became dormant, stained and pigmented hyphae and microsclerotia were increasingly evident. This study reveals the systemic association of dark septate fungi with aboveground tissues of B. eriopida.}, author = {Aaltonen, R.E. and J.R. Barrow} } @proceedings {50738, title = {Managing stocking density in real-time}, year = {2003}, month = {July 26-August 1}, pages = {840-843}, address = {Durban, South Africa}, abstract = {Individual prescription animal management will soon be possible by combining electronics and animal behavior. Once a proper stocking rate has been established, controlling stocking density and ultimately forage utilization is a manager{\textquoteright}s second biggest challenge. Of the multifaceted tools and techniques used to alter animal distribution, none offer the unique possibilities of Virtual Fencing (VF). VF combines Global Positioning System (GPS) technology and electro-mechanically produced bilateral cues in a new paradigm to control free-ranging animal location and direction of movement in a humane and reproducible manner in real-time. The only ground-based hardware is the device worn by the animal in which a central processing unit (CPU) uses Radio Frequency (RF) signals captured from GPS satellites to determine the animal{\textquoteright}s location. Geographically referenced virtual boundaries (VB) programmed into the unit{\textquoteright}s Geographic Information System (GIS) are combined with the GPS data to determine when a VB has been penetrated and at what angle. When this occurs, algorithms in the CPU determine to which side of the animal the fail-safe programmable repertoire of cues, having a range of intensities, is to be applied to encourage the animal to move away from the VB using the least intense cues and shortest route possible. Programming the VB to move or surround individual animals, allows dispersal or gathering of animals autonomously. Proof-of-concept has been established using a neck saddle prototype. Equipment designs, attachment locations, heart rate changes arising from cuing and the use of individual electronic animal identification and cellular communication technologies with VF will be covered.}, url = {/files/bibliography/03-033.pdf}, author = {D.M. Anderson and C.S. Hale and R. Libeau and B. Nolen} } @article {50762, title = {Morphologies and stable and radiogenic isotope composition of pedogenic carbonate in Late Quaternary relict and buried soils, New Mexico: an integrated record of pedogenic overprinting}, journal = {Journal of Sedimentary Research}, volume = {72}, year = {2003}, note = {//?//LTER IV//}, month = {2003}, pages = {809-822}, abstract = {

This petrographic and stable (δ13C and δ18O) and radiogenic (14C) isotope study of pedogenic carbonates from late Quaternary soils in the Rio Grande Rift region of New Mexico documents that carbonate formation in semiarid to arid soils (Aridisols) occurs principally by overprinting and can result in a complex petrographic and isotopic record. With increasing duration of exposure (\<7 to 900 ky) of the four studied profiles, pedogenic carbonates exhibit: (1) an increase in the degree of intraprofile δ13C and δ18O heterogeneity, (2) increased development of down-profile δ13C and δ18O trends, (3) an increase in the degree of intermorphologic and intramorphologic stable-isotope variation, commonly in samples distributed laterally within narrow depth intervals, and (4) development of covariation between δ13C and δ18O values. Radiocarbon ages of the carbonates permit assessment of the degree of isotope heterogeneity in contemporaneous carbonates and recognition of temporal isotopic trends.

The range of exposure times recorded by the studied soils are analogous to those associated with the formation of fossil soils. This makes the studied soils ideal for evaluating the origin of stable-isotope heterogeneity in paleosol carbonates and the implications of those heterogeneities for the use of stable isotopes as paleoenvironmental proxies. Specific implications of this study include the following: (1) Pedogenic carbonates that form by overprinting are a cumulative record of the soil conditions present during their accumulation; thus, isotope analysis of overprinted carbonates can result in "time averaging" of changing climatic, paleoenvironmental, and paleoecologic conditions. (2) Carbonates may record only a fraction of the duration of development of their host profile. (3) There is a high level of uncertainty associated with using the sequence of morphologic development of carbonate as a function of time or maturity in paleosols. (4) An exponential decrease in carbonate δ13C values with depth in a paleosol does not imply that the carbonates are contemporaneous or accumulated under invariant soil conditions. (5) Shifts in soil and paleoclimatic conditions may be recorded by the δ13C and δ18O values of carbonates distributed within narrow depth intervals of a given soil in addition to those distributed down-profile, or even from within individual carbonate samples.

}, keywords = {article, articles, isotopes, composition, journal, journals, morphology, pedogenic carbonates, quaternary geology, soil formation, soil, carbonate, soil, pedogenic carbonates, soil, radiogenic isotopes}, doi = {10.1306/040102720809}, url = {files/bibliography/JRN00392.pdf}, author = {Deutz, P. and Montanez, I. P. and Curtis H. Monger} } @article {50786, title = {Modeling runoff and runon in a desert shrubland ecosystem, Jornada Basin, New Mexico}, journal = {Geomorphology}, volume = {53}, year = {2003}, note = {//NMSU//LTER IV//}, month = {2003}, pages = {45-73}, abstract = {

A new two-dimensional (2D) distributed parameter model is developed to simulate overland flow in two small semiarid shrubland watersheds in the Jornada Basin, southern New Mexico. The model is event-based and operates at the scale of the individual shrub, each watershed being represented as a set of 1-m2 cells. In the model flow directions and volumes are computed by a second-order predictor-corrector finite difference scheme (Davis, 1988), which is employed to solve the two-dimensional kinematic wave equation. Thus, flow routing is computed implicitly and may vary in response to flow conditions. The model uses only six parameters for which values are obtained from field surveys and rainfall simulation experiments. The model underpredicts runoff from the watersheds due to the measured values of saturated hydraulic conductivity Ks for intershrub areas being too high. This is because the runoff plot experiments used to estimate Ks were conducted at the beginning of summer on surfaces with degraded seals, whereas most summer storms occur on surfaces that have experienced recent rainfall and have better developed seals. Model performance is much improved when Ks is treated as a calibration parameter. The importance of runon infiltration in supplying water to shrubs is investigated for a range of rainfall and antecedent soil moisture conditions using the 2D model. On average, runon infiltration accounts for between 3 and 20\% of the total infiltration in the soil under a shrub. The most favorable conditions for runon infiltration are an initially wet soil and a low mean rainfall rate.

}, keywords = {article, articles, hydrology, grassland, hydrology, rainfall simulation, hydrology, runon, hydrology, shrubland, hydrology, surface runoff, journal, journals, model, runoff, model, runon, runoff, model, water flow, model}, doi = {10.1016/S0169-555X(02)00347-1}, url = {files/bibliography/JRN00391.pdf}, author = {David A. Howes and Athol D. Abrahams} } @inbook {50797, title = {Millennial-scale climate variability and ecosystem response at the Jornada LTER site}, booktitle = {Climate variability and ecosystem response at long-term ecological research sites}, year = {2003}, note = {//NMSU,USDA//LTER IV//Added 11/2/2005, Updated 5/15/2006.ProCite field[6]: In}, month = {2003}, pages = {341-369}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, abstract = {The Jornada Long-Term Ecological Research (JRN LTER) program consists of studies superimposed on three research entities, the Jornada Experimental Range, the Chihuahuan Desert Rangeland Research Center, and the Desert Soil-Geomorphology project. The JRN site is in the northern part of the Chihuahuan Desert and represents, for the LTER network, the desert shrubland and desert grassland ecosystems of the southwestern United States. Climate data at the Jornada site and surrounding area span the last 110 years. Ecological data span the last 144 years. Jornada LTER researchers still struggle to understand how ecosystems respond to climate variability. Human land use (including cattle grazing, brush control, and habitat fractionation) is an important factor that complicates this question and produces external pressure on Jornada ecosystems. The cause-and-effect relationship between climate and ecosystems in prehistoric times is even more uncertain. Here evidence is limited to indicators, such as former lake shorelines, plant fossils in packrat middens, fossil pollen, 13C/12C rations in paleosols, and erosion rates. When some indicators are used by themselves, circularity arises if a conclusion about ecosystem response to climate change is based on an inference about climate change, which is based, in turn, on ecosystem change. For example, grasslands increased at the end of the middle Holocene as the result of increased rainfall, where the interpretation of increased rainfall is based on increased grass pollen in the middle Holocene sediments. Also focusing on millennial-scale climate and ecosystem variability, this chapter briefly discusses historic variability for comparison and as a means for describing the setting. The historic-prehistoric boundary for the Jornada area has been set at A.D. 1850.}, keywords = {book, books, carbon isotope ratios, chapter, chapters, climate change, ecosystem response, climate variability, ecosystem response, climate variability, fossil pollen, Jornada LTER, LTER site, packrat middens, pedogenic carbonates, report, reports, soil, geomorphology, vegetation change}, author = {Curtis H. Monger}, editor = {Greenland, David and Goodin, Douglas G. and Raymond C. Smith (eds.)} } @conference {50816, title = {Molecular fluorescence spectroscopy: Identification of plants from extract solutions}, booktitle = {30th Annual Meeting, Federation of Analytical Chemistry and Spectroscopy Societies}, year = {2003}, month = {October 19-23, 2}, pages = {124}, address = {Ft. Lauderdale, FL}, abstract = {The determination of plant species included in the diets of free-ranging animals is of significant importance. Applications of such information range from monitoring domestic animals to providing data for land-use policy decisions. Current methodologies are both time and labor intensive and are dependent on the visual acuity of the analyst (e.g., microhistological analysis of post-digestive samples). Efforts have been undertaken to develop a rapid, objective technique for elucidation of diet compositions using fluorescence measurements of extracts in buffered saline. Unique fluorescence spectral signatures for each of six common forage plants found in the rangelands of the northern Chihuahuan Desert have been recorded and evaluated for the identification of those species. The results of that study will be presented with an appropriate statistical analysis of those data. The feasibility of the use of fluorescence signatures for the elucidation of animal diets will be discussed.}, author = {G.D. Rayson and T.L. Danielson and D.M. Anderson and Richard E. Estell and E.L. Fredrickson and Kris Havstad} } @conference {50817, title = {Measuring soil redistribution in semiarid grass and shrub communities using 137-Cesium}, booktitle = {Hydrology of Mediterranean and Semi Regions Conference}, year = {2003}, note = {Entered by Beltsville;}, pages = {33}, address = {Montpellier}, abstract = {Soil redistribution across semiarid landscapes is often associated with changing vegetation patterns. Semiarid grasslands tend to have uniform patterns of soil properties while shrublands have nonuniform patterns of soil properties. In the 1950{\textquoteright}s and 1960{\textquoteright}s radioactive Cesium-137 was deposited uniformly across the landscape from atmospheric fallout from nuclear weapon tests. Once in contact with the soil, Cs-137 is rapidly and strongly adsorbed to soil particles and any redistribution is due to the physical movement of soil particles. Thus, by measuring Cs-137 redistribution across the landscape, soil redistribution can be estimated. Soil profiles were collected from grass (Black Grama and Tobosa) and shrub (Tarbush and Mesquite) sites at the USDA-ARS Jornada Experimental Range in the Northern Chihuahuan Desert in New Mexico USA. Concentrations of Cs-137 were determined in these soil profiles. At the Black Grama and tobosa sites, Cs-137 was uniformly distributed across the sites. At mesquite sites, Cs-137 was concentrated in the dune area under mesquite shrubs with little to no Cs-137 in the interdune areas indicating soil redistribution from the interdune space to the dune. At the tarbush sites Cs-137 concentration was variable. Calculated erosion rates varied with vegetation type and within vegetation type. The black grama showed no net soil loss, while the tobosa site showed a net soil deposition of 5 t/ha/yr. The tarbush site had both soil erosion and deposition depending on sample location. The mesquite sites were also highly variable depending on location of the site and whether samples were taken from the dune area under the mesquite plant or from the space between dunes. Interdune areas always showed soil loss while some dunes showed gains in soil and others showed soil loss. This study shows that Cs-137 data from soil profiles can provide insights into the redistribution patterns of soil resources in these semiarid grass and shrub communities.}, author = {Jerry Ritchie and Jeffrey E. Herrick and Ritchie, C.A.} } @conference {50832, title = {Manipulation of resource heterogeneity in restoration of arid grasslands and shrublands}, booktitle = {15th Annual International Society for Ecological Restoration Conference}, year = {2003}, month = {August 2003}, address = {Austin, TX}, abstract = {Degradation of arid ecosystems is often signaled by the changes in the distribution of soil and water resources and by changes in plant species composition. For example, shrub invasion of grassland typically leads to resource redistribution into larger resource islands that are more widely spaced and more different from the surrounding matrix than those associated with grasses, while increased grass cover has the opposite effect. In both cases, positive feedbacks often develop, reinforcing the altered resource distribution and increasing resistance to management efforts to restore the pre-existing plant community. Changes in vegetation spatial structure can alter other important ecosystem processes as well. In parts of the western USA, the more continuous fuel of cheatgrass increases fire frequency, extent and intensity which is unfavorable for most shrub restoration. In shrublands at Jornada Experimental Range in southern New Mexico, the larger interspaces between shrubs allow increased erosion which may hinder grass establishment. Managed redistribution of resources, such as concentrating resources in grasslands to encourage the establishment of shrubs or reducing the spatial heterogeneity of resources in shrublands to promote the establishment of grasses, may be an effective component of restoration projects. The effectiveness of manipulating the spatial distribution of resources for the restoration of shrubs in cheatgrass-dominated grasslands and the restoration of grasses in mesquite and creosote-dominated shrublands is predictably influenced by site and species characteristics and by the degree to which important ecosystem processes, such as fire and erosion, are modified by changes in the spatial distribution of resources.}, url = {www.ser.org/content/abstracts.asp}, author = {S. Tartowski and Salo, L.F. and Jeffrey E. Herrick} } @article {50837, title = {Mechanisms of competition: thermal inhibition of tree seedling growth by grass}, journal = {Oecologia}, volume = {133}, year = {2002}, note = {//NONE//LTER IV//}, month = {2002}, pages = {120-130}, abstract = {

The relative importance of thermal interference and competition for below-ground resources in the inhibition of tree seedling growth by grass was determined under field conditions. Snow gum (Eucalyptus pauciflora) seedlings were grown in bare soil or soil covered with either live grass or straw. Covering soil with straw produced thermal conditions in soil and air that were indistinguishable from those associated with live grass. In contrast, seedlings grown in bare soil experienced more rapid increase in soil temperatures during late winter and spring, less frequent and less severe frosts, and temperature maxima that more closely followed those of the atmosphere than seedlings growing in live grass or straw. After 1\ year, seedlings in bare soil had four times the biomass of those grown in grass or straw. Inhibition of seedling growth by grass was attributed to alteration of the thermal environment which caused (1) seedlings to have a short growing season largely restricted to summer, (2) temporal separation in competition for resources with consumption of below-ground resources by grass in spring reducing availability of resources to support tree seedling growth in early summer, and (3) seedlings to be more subject to stress from temperature extremes. These results show that thermal interference plays a major role in interactions between plants.

}, keywords = {article, articles, competition, grass, competition, thermal inhibition, competition, trees, journal, journals}, doi = {10.1007/s00442-002-1044-z }, url = {files/bibliography/JRN00361.pdf}, author = {Ball, M. and Egerton, J. J. G. and Lutze, J. L. and V. P. Gutschick and Cunningham, R. B.} } @conference {50849, title = {Meeting in the middle: Bottom-up and top-down scaling approaches}, booktitle = {17th Annual Symposium, US-International Association for Landscape Ecology}, year = {2002}, month = {April 23-25, 200}, pages = {99}, address = {Lincoln, NE}, 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 Sarah Goslee and R.A. Pielke} } @conference {50863, title = {Mowing versus fire on expansion of black-tailed prairie dogs reintroduced into Chihuahuan Desert grasslands}, booktitle = {87th Annual Meeting, Ecological Society of America}, year = {2002}, month = {August 4-9, 2002}, pages = {352}, address = {Tucson, AZ}, abstract = {Black-tailed prairie dogs (Cynomys ludovicianus) populations have declined more than 98\% due to eradication programs, habitat loss, and introduced pathogens. Active conservation measures for this species, including reintroduction, are under way in a number of areas. Because of their effects on landscape pattern and ecosystem process, they may act as a keystone species in desert grassland communities. As part of a larger study of reciprocal effects of landscape and ecosystem factors on establlishment and growth of prairie dog colonies, we investigated the effects of fire and mowing in promoting colony numerical growth and areal expansion. Three prairie dog colonies were established in the northern Chihuahuan Desert in 1998-1999 ranging in size from 1.27 to 8 ha. Adjacent to each colony we established six 50m x 50m experimental plots randomly assigned to burn or mow treatments. The response variable was number of new burrows appearing in each experimental plot. No significant differences were detected in the number of new burrows in burned vs. mowed plots, suggesting that either fire or mowing can be used interchangeably as management tools in the reintroduction of prairie dogs.}, author = {E.L. Fredrickson and C.A. Anderson and P. L. Ford and J. Truett and G. Roemer} } @article {50872, title = {Modelling stomatal conductance of field-grown sunflower under varying soil water status and leaf environment: comparison of three models of response to leaf environment and coupling with ABA-based model of resposne to soil drying}, journal = { Plant, Cell, and Environment}, volume = {25}, year = {2002}, note = {//NONE//??//}, month = {2002}, pages = {1423-1434}, author = {V. P. Gutschick and Simonneau, T.} } @conference {50960, title = {Managing animals within virtual boundaries}, booktitle = {54th Annual Meeting Society for Range Management}, year = {2001}, month = {February 2, 2001}, pages = {Abstract No. 9}, address = {Kailua-Kona, HI}, abstract = {Combining Global Positioning System (GPS) technology and electro-mechanically produced cues offers a new paradigm in controlling free-ranging animals. Preliminary tests using autonomously applied bilateral cues indicate the method is humane and reproducible when used to alter a beef cow{\textquoteright}s location and direction of movement. A central processing unit (CPU) within the device worn by an animal uses Radio Frequency (RF) signals captured from GPS satellites to determine the animal{\textquoteright}s location. Geographically referenced virtual boundaries (VB) are programmed into the unit{\textquoteright}s Geographic Information System (GIS). The device integrates these two data sets to determine the animal{\textquoteright}s location with respect to the closest VB. If a VB is penetrated, algorithms in the CPU determine to which side of the animal the programmable repertoire of cues is to be applied to encourage the animal to move away from the VB using the shortest route possible. The cues are administered in a fail-safe cascade fashion from least to most aversive and to only one side of the animal at a time depending on the animal{\textquoteright}s angle of approach to the VB. If a VB is programmed to move or surround individual animals, dispersal or gathering of animals is automated. The device can be used with individual electronic animal identification to further facilitate individual animal management. Proof-of-concept has been evaluated using neck saddle prototypes. Various device designs and attachment locations will be discussed. Combining electronics with animal behavior will make individual prescription animal management a commercial reality in the 21st century.}, keywords = {control, device designs, free-ranging animals, Global Positioning System, radio frequency, virtual boundaries}, author = {D.M. Anderson and C.S. Hale} } @conference {50967, title = {A method for analyzing active internal colonization of dark septate fungal endophytes in grasses and shrubs native to arid southwestern USA rangelands}, booktitle = {Third International Conference on Mycorrhizae}, year = {2001}, month = {July 8-13, 2001}, pages = {Abstract No. P1-68}, address = {Adelaide, Australia}, abstract = {Dominant native grasses and shrubs in arid southwestern USA rangelands are more extensively colonized by dark septate fungal endophytes (DSE) than by conventional mycorrhizal fungi. These endophytes are widespread colonizers in most ecosystems, but their ecological function is currently unresolved. They are readily observed as stained or melanized septate hyphae and microsclerotia on the root surface and in the cortex using fungus specific stains that bind to chitin, a common wall component. Roots of grasses and shrubs native to the northern Chihuahuan Desert were stained with sudan IV, specific for lipids, and analyzed with high magnification differential interference microscopy. Inconspicuous internal hyphal extensions of stained or pigmented hyphae were observed that were not visible using fungus specific stains. These structures were observed in a much greater frequency than the commonly recognized stained or pigmented structures in physiologically active roots. Differential responses to staining were attributed to structural differences and levels of chitin incorporation in the fungal wall. Internal hyphae varied in diameter, wall thickness, and visibility and in many cases were detectable only because of the positive staining of lipids in fungal vacuoles. Internal hyphae grew both inter and intracellularly within the cortex and sieve elements of the vascular cylinder and at time contained substantial quantities of lipids. This method promises to be effective for studying the extent, nature, and possible function of DSE fungi in native ecosystems.}, keywords = {analyzing, arid rangelands, dark septate, fungal endophytes, grasses, internal colonization, shrubs}, author = {J.R. Barrow and Aaltonen, R.E.} } @conference {51022, title = {Monitoring grassland, shrubland and savanna ecosystems: LCTA versus an integrated soil and vegetation monitoring protocol}, booktitle = {86th Annual Meeting, Ecological Society of America}, year = {2001}, month = {August 5-10, 200}, pages = {322}, address = {Madison, WI}, abstract = {The Land Condition-Trend Analysis (LCTA) program is the U.S. Army{\textquoteright}s protocol for monitoring trends in land condition on Army installations. We compared the LCTA vegetation monitoring methods with a new integrated soil and vegetation rangeland monitoring protocol that was developed specifically for grasslands, shrublands and savannas. Data were collected by applying both methods to previously established LCTA transects. We the evaluated the cost (time efficiency) of the two protocols. In addition, we assessed the ability of both methods to produce indicators that relay meaningful information about ecosystem function and the effects of disturbance at each site. Specifically, we compared each protocol{\textquoteright}s ability to detect changes in three ecosystem attributes: soil and site stability, hydrologic function and biotic integrity. Preliminary comparisons indicated the new methods are more sensitive to changes in soil land site stability and hydrologic function. This is due to the new protocol{\textquoteright}s inclusion of soil measurements and measurements of spatial patterns in vegetation. The new methods also address a broader range of biotic integrity indicators through the inclusion of soil measurements.}, author = {Laura M. Burkett and Jeffrey E. Herrick and M.D. Remmenga and M. Hildegard Reiser} } @article {50979, title = {Morphology and isotope heterogeneity of Late Quaternary pedogenic carbonates: implications for paleosol carbonates as paleoenvironmental proxies}, journal = {Palaeogeography, Palaeoclimatology, and Palaeoecology}, volume = {166}, year = {2001}, note = {//?//LTER IV//}, month = {2001}, pages = {293-317}, abstract = {

Stable isotope values and radiocarbon ages were determined for pedogenic carbonate microsamples from relict soils and palaeosols from the Rio Grande Rift region of New Mexico. Carbonate nodules and clusters were sampled from fluvial and piedmont soils and palaeosols with widely varying exposure durations (7{\textendash}900\ ky). Pedogenic carbonates from individual soils exhibited irregular relationships between age and depth, ranging in radiocarbon age by <=13\ ky at individual depths. δ18O values, and to a lesser extent δ13C values, likewise had wide ranges within soils. However, comparing the stable isotope values of carbonates with similar radiocarbon ages, within and between soils, revealed consistent trends in stable isotope values over time. δ18O values of pedogenic carbonates tended to decrease with decreasing age 25{\textendash}17 radiocarbon ka, and increased with decreasing age \<15 radiocarbon ka, with a marked shift to more positive values at 9{\textendash}6\ ka. Pedogenic carbonates from the piedmont soils showed minimal variation in δ13C values with either depth or age, although the oldest palaeosol piedmont carbonates (radiocarbon ages of 24.5{\textendash}19.2\ ka) are >=1{\textperthousand} more negative than the younger piedmont palaeosol carbonates. Pedogenic carbonates in the relict fluvial soil, which has by far the longest exposure period, showed the greatest range in δ13C values. Comparing the δ13C values of samples of similar radiocarbon age from the relict fluvial soil indicates a transition from a mixed C3:C4 ecosystem at \~{}11\ ka to an effectively pure C3 ecosystem at \~{}9\ ka, followed by a return to mixed vegetation by \~{}5\ ka. Thus, although C4 vegetation persisted in southern New Mexico through the last glaciation, drought-resistant C3 vegetation became dominant at \~{}9\ ka, prior to significant strengthening of the summer monsoon. This study illustrates that the stable isotope values of carbonate nodules and clusters from relict soils and/or slowly buried palaeosols can be used for palaeoenvironmental reconstructions in the context of a detailed chronologic framework.

}, keywords = {article, articles, carbonate, paleosol, carbonate, pedogenic, isotopes, heterogeneity, journal, journals, morphology}, doi = {10.1016/S0031-0182(00)00214-5}, url = {files/bibliography/JRN00340_0.pdf}, author = {Deutz, P. and Montanez, I. P. and Curtis H. Monger} } @article {50995, title = {Modeling invasive weeds in grasslands: The role of allelopathy in Acroptilon repens invasion}, journal = {Ecological Modelling}, volume = {139}, number = {1}, year = {2001}, month = {February 1, 2001}, pages = {31-45}, abstract = {We used an individual plant-based simulation model (ECOTONE) to evaluate the importance of allelopathy and soil texture to the invasion of semiarid grasslands by Acroptilon repens. We also assessed the sensitivity of model results to the negative effects of allelochemicals on recruitment and growth of perennial grasses. The ECOTONE model was parameterized for a shortgrass community in eastern Colorado. Experimental simulations used plots with four soil textures and a range of levels of plant sensitivity to allelochemicals. Simulation results showed that A. repens did not dominate the aboveground biomass unless native species were negatively affected by allelochemicals. At moderate levels of plant sensitivity, A. repens became dominant faster and reached a larger proportion of total biomass on fine- compared to coarse-textured soils. Community composition and rate of A. repens dominance were more affected by the sensitivity of plant growth to allelochemicals than sensitivity of recruitment. Allelopathic interactions were an important component of the invasion dynamics of this perennial invasive weed, and further field investigation is warranted.}, url = {/files/bibliography/01-026.pdf}, author = {Sarah Goslee and Debra C. Peters and Beck, K.G.} } @proceedings {50999, title = {Monitoring methodology for pasture degradation and restoration}, year = {2001}, month = {April 2-9, 2001}, pages = {2-6}, address = {San Jose, Costa Rica}, abstract = {

A simple, flexible, quantitative methodology has been developed to monitor the ecological sustainability of grassland, shrubland and savanna ecosystems. Three core soil and vegetation measurements are supplemented by optional measurements to generate indicators of three key ecosystem attributes: soil and site stability, hydrologic function and biotic integrity. The optional measurements are selected based on monitoring objectives and site-specific resource concerns, such as compaction. The methodology is designed to facilitate active participation of farmers and ranchers in both design and implementation. The approach is supported by an extensive research program of the USDA Agricultural Research Service and will be summarized in a manual to be published in both English and Spanish.

}, author = {Jeffrey E. Herrick} } @conference {51012, title = {Managing rangelands: Implications of a paradigm shift in the ecology of arid and semiarid ecosystems}, booktitle = {86th Annual Meeting, Ecological Society of America}, year = {2001}, month = {August 5-10, 200}, pages = {21}, address = {Madison, WI}, abstract = {Arid and semiarid ecosystems often exhibit unanticipated, nonlinear responses to environmental events and to management activities. While the importance of nonlinear dynamics and thresholds has been widely documented, most rangeland management is still based on the classical Clementsian understanding of succession and retrogression. The objectives of this talk kare to review how recent ecological theory has been integrated into resource management, to identify the scientific and nonscientific limitations of this integration and, based on these limitations, to define types of research land managers need to effectively apply modern ecological theory. The concept of multiple states and transitions is being integrated into revisions of the ecological site descriptions of the Natural Resource Conservation Service. The Bureau of Land Management is implementing the concept of thresholds in their qualitative rangeland health assessments. A Amore complete integration into resource management is limited by a poor understanding of states, transitions and thresholds in many arid and semi-arid ecosystems, and the lack of scientifically-based protocols for selecting management options when uncertainty exists about the presence and relationship to one or more thresholds. These limitations are compounded by administrative structures and competing resource demands. Ecological research is needed to clearly define environmental factors that control states, transitions, and thresholds for the variety of rangeland ecosystems. Adaptive management is paramount and will require collaboration among scientists and managers to successfully apply these increasingly complex models.}, author = {L. A. Joyce and D.A. Pyke and Jeffrey E. Herrick} } @article {51028, title = {Modelling vegetation change and land degradation in semiarid and arid ecosystems: an integrated hierarchical approach}, journal = {Advances in Environmental Monitoring and Modeling}, volume = {1}, number = {2}, year = {2001}, month = {May 1, 2001}, pages = {1-29}, abstract = {Despite the dedication of significant human, financial and technological resources, dryland degradation continues unabated in both the developed and developing world. Many of the causes have been described and the consequences extensively documented. Here, we argue that the failure of attempts to stop or reverse dryland degradation can be explained by a failure to 1) recognize when ecosystems have crossed ecological, edaphic o geomorphic thresholds, and 2) identify and address the properties and/or processes at relevant scales that confer resistance and resilience. We illustrate how simulation models can be used to address these limitations using examples from one type of model, an individual-based gap dynamics model of grasslands and shrublands (ECOTONE). We used ECOTONE to predict the effects of climatic fluctuations and disturbance frequency on local and regional patterns in species dominance and composition. Results show that patterns in dominance between 2 perennial grasses (Bouteloua gracilis, Bouteloua eriopoda) at the biome transition zone are not predictable based on responses within each biome. An increase in disturbance frequency at the ecotone shifted plant communities to dominance by the short-lived B. eriopoda from communities codominated by B. gracilis or the shrub Larrea tridentata. We propose a strategy that addresses problems in semiarid and arid ecosystems more effectively than previous approaches based on an integrated, hierarchical modeling approach. This approach employs multiple tools, such as geographic information systems, state and transition models, remote sensing, and expert knowledge, in an iterative approach with simulation models. This strategy is applicable to research on processes of dryland degradation and management projects to stop or reverse degradation.}, url = {/files/bibliography/01-043.pdf}, author = {Debra C. Peters and Jeffrey E. Herrick} } @article {51087, title = {Multivariate characterization of perennial vegetation in the northern Chihuahuan Desert}, journal = {Journal of Arid Environments}, volume = {44}, number = {3}, year = {2000}, month = {March 1, 2000}, pages = {305-325}, abstract = {

We surveyed vegetation at 100 sites in southern New Mexico to establish a benchmark for monitoring vegetation change. Sites were selected in a stratified random design based on a classified AVHRR image. Two shrubs (Larrea tridentata and Prosopis glandulosa) are the most important contributors to perennial cover in the area. Principal components analysis (PCA) and detrended correspondence analysis (DCA) both clearly delineate these shrublands from the smaller number of compositionally varied grassland sites. A latitudinal trend in DCA axis 1 scores suggests that encroachment of shrubs into grasslands is most pronounced in the southern portion of the study area.

}, keywords = {Chihuahuan Desert, Larrea tridentata, perennial vegetation, prosopis glandulosa}, doi = {10.1006/jare.1999.0597}, url = {/files/bibliography/00-005.pdf}, author = {A. R. Johnson and S.J. Turner and Walter G. Whitford and A.G. de Soyza and Justin Van Zee} } @article {51094, title = {Microbial diversity and activity of disturbed soil in the northern Chihuahuan Desert}, journal = {Biology and Fertility of Soils}, volume = {32}, number = {3}, year = {2000}, month = {July 1, 2000}, pages = {243-249}, abstract = {

The effects of intense grazing, seasonal drought, and fire on soil microbial diversity (substrate utilization) and activity in a northern Chihuahuan Desert grassland were measured in summer 1997, winter 2998, and spring 1998. Intense livestock grazing was initiated in winter 1995, burning occurred in August 1994, and drought stresses were imposed from October 1994 to June 1997. Microbial diversity was inferred from the carbon substrate utilization patterns in both gram (+) and gram (-) Biolog plates. Microbial activity was estimated by the activity of selected enzymes. Neither microbial diversity nor activity was affected by grazing. The interaction of intense grazing and stress subtreatments only occurred in spring for one set of diversity measurements. The maximum microbial diversity and activity occurred in the winter-drought-stress subplots in summer and spring. Burning reduced microbial diversity and most enzyme activities as compared to the control in summer and spring. Microbial diversity was also lower in summer-drought-stress subplots than in the control in summer and spring. Microbial diversity was highest in summer, intermediate in winter, and lowest in spring. Microbial activity was generally higher in summer and lower in winter. It was concluded that substrate availability was the most important factor affecting the diversity and activity of soil microorganisms within a season. Soil moisture was not the factor causing differences in microbial diversity and activity among the stress treatments, but it was a predictor for some microbial responses under a particular stress.

}, keywords = {Chihuahuan Desert, grazing, microbial diversity, soil}, doi = {10.1007/s003740000242 }, url = {/files/bibliography/00-011.pdf}, author = {Liu, X. and W. C. Lindemann and Walter G. Whitford and R.L. Steiner} } @article {51108, title = {Morphological characteristics of shrub-coppice dunes in desert grasslands of southern New Mexico derived from scanning LIDAR}, journal = {Remote Sensing of Environment}, volume = {74}, number = {1}, year = {2000}, month = {October 15, 2000}, pages = {26-44}, abstract = {

Since the 1880{\textquoteright}s, rangeland vegetation in southern New Mexico has changed dramatically over widespread areas, typically with shrubs displacing native grasslands. Coincident with these changes in vegetation dominance are increases in soil erosion, stream channel cutting, and shrub-coppice dune formation on sandy soils. Where marked differences in vegetation type from grassland to honey mesquite shrubland have occurred, the local topography has been transformed with previously flat mesa becoming rolling duneland. The size, distribution, and morphological characteristics of these dunes have an important impact on fluxes of energy and nutrients at the surface as well as rendering the land far less useful as grazingland for domestic livestock. These shrub-coppice dunes and the mesquite shrubs which grow on them may be considered roughness elements. Quantifying their morphology is important for the calculation of aerodynamic roughness length and displacement height. This article describes the application of active scanning laser remote sensing techniques in providing accurate estimates of the three-dimensional shapes and areal distributions of dune and interdune areas. It shows that coarse scanning laser can be used to measure the morphological characteristics of shrub-coppice dunes in the desert grasslands of southern New Mexico with acceptable accuracy and precision for a range of uses including important geomorphological and hydrological applications. The use of scanning laser systems, together with optical multispectral data, is shown to be highly synergistic providing information which is not easy to obtain via other survey methods.

}, keywords = {morphological characteristics, multispectral data, scanning laser systems, shrub-coppice dunes}, doi = {10.1016/S0034-4257(00)00084-5}, url = {/files/bibliography/00-019.pdf}, author = {A. Rango and M. Chopping and Jerry Ritchie and Kris Havstad and William P. Kustas and T. J. Schmugge} } @proceedings {51112, title = {Monitoring physical and biological properties at the Sevilleta LTER using remote sensing}, volume = {IAHS Publication No. 267}, year = {2000}, note = {Proceedings of a symposium held at Santa Fe, NM, April 2000ARIS entry by Beltsville}, month = {2001}, pages = {234-236}, publisher = {Remote Sensing and Hydrology}, address = {Santa Fe, NM}, abstract = {In 1997, the USDA Agriculture Research Service, Hydrology Laboratory began collecting remotely sensed ground, aircraft, and satellite data on the physical and biological states of two semi-ecosystems (grass and shrub) typical of the Sevilleta Long-Term Ecological Research Program site. Remote sensing measurements were made at Sevilleta in May/June and in September/October of 1997, 1998, and 1999. Radiance, measured at ground an aircraft platforms, was 12 to 40 percent higher for a 30-meter squared area at the shrub site when compared with the grass site. Landscape surface temperatures were similar in the morning but were 3 to 5 degrees Celsius higher under the shrub when compared with the grass site by 1:00 p.m. local time. The shrub site had a lower Leaf Area Index indicating lower surface cover at the shrub site giving a higher soil contribution to the total radiance measured. These differences could have significant effects on the energy and water balances of the Sevilleta site if shrubs continue to expand at the expense of the grassland.}, keywords = {aircraft, data, ground, monitoring, remote sensing, satellite, Sevilleta LTER}, url = {/files/bibliography/01-076.pdf}, author = {Jerry Ritchie and T. J. Schmugge and A. Rango and Schiebe, F.R.} } @article {51120, title = {Movements during colony founding by queens of the honeypot ant (Myrmecocystus mimicus Wheeler)}, journal = {American Midland Naturalist}, volume = {144}, year = {2000}, note = {//USDA//LTER IV//}, month = {2000}, pages = {439-444}, abstract = {

Habitat selection by ant queens has been little studied even though it may be a critical component of colony founding. We describe the movement pathways of honey ant queens (Myrmecocystus mimicus Wheeler) searching for sites on the ground to initiate nests. Typical paths may include segments of directional movement that are interrupted by segments of area-restricted search. Mechanisms producing area-restricted search might include variable step lengths and looping behavior. Cues that prompt the switch to local search remain undetected.

}, keywords = {ant community, grazing effects, ant, biodiversity, ant, honeypot, ant, Myrmecocystus mimicus, ants, habitat selection, article, articles, grazing, ant communities, habitat preference, ants, journal, journals}, doi = {10.1674/0003-0031(2000)144[0439:MDCFBQ]2.0.CO;2}, url = {files/bibliography/JRN00306.pdf}, author = {Robert L. Schooley and Brandon T Bestelmeyer} } @proceedings {51131, title = {Mesquite-grassland ecotones in the Chihuahuan Desert}, volume = {RMRS-P-11}, year = {1999}, month = {August 12-14, 19}, pages = {84-87}, publisher = {U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station}, address = {Ogden, UT}, abstract = {Many plains and uplands of the Chihuahuan Desert in southern New Mexico are in transition from perennial desert grassland to a mesquite (Prosopis glandulosa)- dominated shrubland. On the Chihuahuan Desert Rangeland Research Center north of Las Cruces, from 1982 to 1996, mesquite aerial cover increased from 1.9 to 4.5\% and density increased from 123 to 176 plants ha-1, with recruitment averaging 3.5 plants ha-1yr-1. Shrubs encroach into grasslands by individual plants becoming established and, over time, creating patches of mesquite. These patches expand into islands of mesquite with a greater biodiversity than the surrounding grasslands. The mesquite islands eventually coalesce into the mesquite "front" and biodiversity decreases. Thus, the current grass-shrublands may best be considered as ecotones, both spatially and temporally.}, url = {/files/bibliography/99-001.pdf}, author = {Reldon F. Beck and R.P. McNeely and Gibbens, Robert P.}, editor = {McArthur, E. Durant and Ostler, W. Kent and Wambolt, Carl L.} } @inbook {51133, title = {Management for carbon sequestration in rangelands: soil organic matter, soil aggregation, and exploiting heterogeneity}, booktitle = {Carbon Sequestration Potential of US Grazing Lands}, year = {1999}, month = {1999}, publisher = {Ann Arbor Press}, organization = {Ann Arbor Press}, address = {Chelsea, MI}, author = {S.B. Bird and Jeffrey E. Herrick and Wander, M.M.}, editor = {Follett, R.F.} } @article {51135, title = {Managing low-output agroecosystems sustainably: the importance of ecological thresholds}, journal = {Canadian Journal of Forest Research}, volume = {29}, year = {1999}, month = {1999}, pages = {1112-1119}, abstract = {Managing vegetation to achieve ecological, economic and social goals is difficult. Inherent complexity among ecosystem components and unpredictable climate often limit opportunities for converting cultural inputs to harvestable products. In addition, the long lag time between treatment and financial return makes capital investment in vegetation management economically risky. One tool that can assist land managers in dealing with these constraints is the identification of ecological thresholds and elucidation of processes that signal undesirable change long before it is entrained. This approach places a premium on detecting degrading processes and implementing management responses in the initial stages of land degradation and on limiting inputs to managerial expertise and manipulation of naturally occurring processes. We propose that research and implementation for sustainable land management should shift direction toward identifying ecological thresholds and should focus on developing low-input responses to avoid, rather than restore, land degradation.}, url = {/files/bibliography/644.pdf}, author = {Joel R. Brown and Jeffrey E. Herrick and Price, D.} } @conference {51149, title = {Modeling the long-term dynamics of an invasive perennial weed in Colorado, USA}, booktitle = {5th World Congress, US-International Association for Landscape Ecology}, volume = {I (A-K)}, year = {1999}, month = {July 29-August 3}, pages = {55}, address = {Snowmass Village, CO}, abstract = {Invasion of native ecosystems by exotic perennial weeds is an increasingly important ecological problem. In most cases, little is known about the potential long-term impact of a species which has been introduced to a new area. Without this knowledge it is difficult to predict the eventual impact of that species on native ecosystems. Our objective was to evaluate the dynamics of the weed Acroptilon repens (Russian knapweed) within the State of Colorado. We used an individual plant-based simulation model (ECOTONE) to examine the long-term dynamics of Russian knapweed in sites across the range of soil textures and climates found in Colorado. Simulation results suggested that Russian knapweed will be most successful over the long term in areas with particular combinations of soil texture and climate. We used the model results to identify the regions of Colorado in which Russian knapweed establishment is likely to lead to continued dominance, as well as sthose regions where knapweed will probably be outcompeted by native grasses. These results can be used to target management programs to the areas where they are most crucial. This approach can also be used to develop appropriate management programs for other perennial weeds.}, keywords = {Colorado, modeling, modelling, perennial weeds, Russian knapweed}, author = {Sarah Goslee and Debra C. Peters and Beck, K.G.} } @mastersthesis {51159, title = {Modeling runoff in a desert shrubland ecosystem, Jornada Basin, New Mexico}, year = {1999}, note = {//NMSU//LTER III//}, month = {1999}, pages = {204}, school = {SUNY at Buffalo}, type = {Ph.D. Dissertationpp}, address = {Buffalo, NY}, abstract = {Two new distributed parameter models, a one-dimensional (1D) model and a two-dimensional (2D) model, are developed to simulate overland flow in two small semiarid shrubland watersheds in the Jornada Basin, southern New Mexico. Both models are event-based and operate at the scale of the individual shrub, each watershed being represented as a set of 1-m2 cells. In the 1D model, the flow network is fixed for the duration of a rainfall event and is generated using the Tarboton (1997) routing algorithm. The volume of flow through this network is computed by numerically solving the one-dimensional kinematic wave equation using a first-order finite difference scheme. In the 2D model flow directions and volumes are computed by a second-order predictor-corrector finite difference scheme (Davis, 1988), which is employed to solve the two-dimensional kinematic wave equation. Thus, flow routing is computed implicitly and may vary in response to flow conditions. Each model uses only six parameters for which values are obtained from field surveys and rainfall simulation experiments. Both models underpredict runoff from the watersheds due to the measured values of saturated hydraulic conductivity Ks for intershrub areas being too high. This is because the runoff plot experiments used to estimate Ks were conducted at the beginning of summer on surfaces with degraded seals, whereas most summer storms occur on surfaces that have experienced recent rainfall and have better developed seals. Model performance is much improved when Ks is treated as a calibration parameter. The importance of runon infiltration in supplying water to shrubs is investigated for a range of rainfall and antecedent soil moisture conditions using the 2D model. On average, runon infiltration accounts for between 3 and 20\% of the total infiltration in the soil under a shrub. The most favorable conditions for runon infiltration are an initially wet soil and a low mean rainfall rate. The two models developed in this study are fundamentally different, but the performances of the two models are remarkably similar. The principal difference between the models is that the 1D model performs better than the 2D model where flow is concentrated into well defined threads or rills. In contrast, the 2D model is better suited to simulating dispersed interrill flow on hillslopes with no rills or channels. Thus, there are advantages and disadvantages to both models, and the choice of model should be guided by the needs of the investigator.}, keywords = {dissertation, dissertations, hydrology, grassland, hydrology, rainfall simulation, hydrology, runon, hydrology, shrubland, hydrology, surface runoff, model, runoff, model, runon, runoff, model, theses, thesis, water flow, model}, url = {LTER Site Manager library book shelf}, author = {David A. Howes} } @article {JRN54959, title = {Modeling Snow Cover and Runoff Response to Global Warming for Varying Hydrological Years}, journal = {World Resource Review}, volume = {11}, year = {1999}, pages = {76-91}, chapter = {76}, abstract = {

The effect of future global warming on the seasonal snow cover and runoff is evaluated in the Rio Grande basin at Del Norte, Colorado for average (1976), low (1977), and high (1979) runoff years. Precipitation data are extrapolated to the respective elevations of the basin by taking into account the snow accumulation obtained from snow cover mapping by satellites. Snow covered areas are used as one of the input variable for the Snowmelt Runoff Model. In order to derive the climate-affected snow covered areas of the future, the decrease of the areal snow water equivalent on 1 April is computed and used to derive new snow cover depletion curves indicative of the accelerated snowmelt in the warmer climate. Day-by-day runoff computations using present temperatures and temperatures increased by +4{\textdegree}C reveal a short-term and seasonal redistribution of runoff which differs according to the character of the selected hydrological years. Winter runoff approximately doubles in 1976 (+ 107\%), considerably increases in 1976 (+ 60\%), and slightly rises in 1977 (+ 22\%). The summer runoff consequently declines in all years, but the seasonal runoff peaks are shifted to earlier in the spring as a result of an earlier beginning of the snowmelt season in the warmer climate.

}, keywords = {climate change, remote sensing, snow and ice hydrology, water resources planning}, url = {files/bibliography/Rango1999-01.pdf}, author = {A. Rango and Martinrc, Jaroslav} } @conference {51182, title = {Multidimensional fluorescence for the investigation of dietary habits of free-ranging herbivores}, booktitle = {Federation of Analytical Chemistry and Spectroscopy Societies Conference}, year = {1999}, month = {October 24-29, 1}, pages = {No. 202}, address = {Vancouver, BC, Canada}, abstract = {The determination of the dietary intake of domestic livestock is necessary for their effective management. This becomes more difficult when the animals are allowed to feed on native flora in open rangeland. Efforts in the past to provide information regarding a particular animal{\textquoteright}s dietary habits have used either highly invasive techniques or methods that are time eand labor intensive and very subjective. The objective of the present stud is to develop instrumentation to enable the interrogation of sample extracts using multi-dimensional fluorescence measurements for objective, rapid determination of plants eaten by a specific animal. Initial work has concentrated on the acquisition and post-processing of the excitation/ emission wavelength fluorescence matrices for each of six plant species typically eaten by free-ranging sheep in the desert southwestern United States. Results of these investigations will be presented with a description of the instrumentation used. The utility of alternate dimensions, including lifetimes and extracting solvent polarity, will be discussed.}, author = {G.D. Rayson and T.L. Danielson and D.M. Anderson and Richard E. Estell and E.L. Fredrickson and Kris Havstad} } @conference {51183, title = {Multidimensional fluorescence for the investigation of dietary habits of free-ranging herbivores}, booktitle = {41st Rocky Mountain Conference on Analytical Chemistry}, year = {1999}, month = {August 1-5, 1999}, pages = {No. 634}, address = {Denver, CO}, abstract = {

The determination of the dietary intake of domestic livestock is necessary for their effective management. This becomes more difficult when the animals are allowed to feed on native flora in open rangeland. Efforts in the past to provide information regarding a particular animal\&$\#$39;s dietary habits have used either highly invasive techniques or methods that are time eand labor intensive and very subjective. The objective of the present stud is to develop instrumentation to enable the interrogation of sample extracts using multi-dimensional fluorescence measurements for objective, rapid determination of plants eaten by a specific animal. Initial work has concentrated on the acquisition and post-processing of the excitation/ emission wavelength fluorescence matrices for each of six plant species typically eaten by free-ranging sheep in the desert southwestern United States. Results of these investigations will be presented with a description of the instrumentation used. The utility of alternate dimensions, including lifetimes and extracting solvent polarity, will be discussed.

}, author = {G.D. Rayson and T.L. Danielson and D.M. Anderson and Richard E. Estell and E.L. Fredrickson and Kris Havstad} } @proceedings {51189, title = {Methods for assessing the health of America{\textquoteright}s rangelands}, volume = {Report QNRM02143}, year = {1999}, note = {August 1-6, 1999Conference was held in 1999 but proceedings weren{\textquoteright}t published until 2002 and reprint not received until December 2003.}, month = {2002}, pages = {1-17}, publisher = {Queensland Department of Natural Resources and Mines}, address = {Brisbane, Australia}, abstract = {Since the publication of the National Research Council{\textquoteright}s {\textquoteright}RANGELAND HEALTH {\textquoteright} New Methods to Classify, Inventory, and Monitor Rangelands,{\textquoteright} and the Society for Range Management report by the Unity in Concepts and Terminology Committee, there has been much activity toward developing a common method to assess rangelands in the United States. Many individuals from several different federal and state agencies have worked together to develop a multi-indicator matrix to determine the {\textquoteright}health{\textquoteright} status of rangelands. Healthy rangelands have been defined as: The degree to which the integrity of the soil, the vegetation, the water, and the air, as well as the ecological processes of the rangeland ecosystem, are balanced and sustained. The site potential is the standard by which {\textquoteright}health{\textquoteright} is judged. A rangeland ecological site must be judged against itself and not against an arbitrary standard or that of a different ecological site. It is apparent that a multi-indicator method of evaluation is necessary. Currently, the evaluation consists of a series of observational questions, some of which can be answered by observation or measurement. Characteristics such as canopy and ground cover, dominant plant species, invasive and noxious plants, and composition of functional/structural plant groups can be measured or observed. The observable data are arranged in a matrix with 17 indicators. Each indicator is compared against the rangeland ecological site description and reference areas that represent the natural range of variability in the ecological site. Each indicator is rated on a sliding scale of five choices from most similar to most dissimilar to the ecological site. Similarity is referenced to the ecological site description and the reference areas. Interagency personnel, universities, scientists, and landowners have tested this methodology in the field in several locations. The indicators have been grouped into three attributes of rangeland health. The three attributes give an indication of the soil or site stability, hydrologic function and biotic integrity of the site. The indicators currently include: rills, water flow patterns, pedestals or terracettes, bare ground, gullies, wind-scoured areas, litter movement, soil surface resistance to erosion, soil surface loss, plant community composition and distribution relative to infiltration and runoff, compaction layer, plant functional/structural groups, plant mortality, litter amount, annual production, invasive plants, and perennial plant reproductive capability. The ratings for each indicator are recorded in a manner that allows for a visual interpretation based on the preponderance of evidence.}, keywords = {assessment, common method, health, indicators, rangelands}, isbn = {0 7345 2668 7}, url = {/files/bibliography/02-106.pdf}, author = {P. L. Shaver and M. Pellant and D.A. Pyke and Jeffrey E. Herrick}, editor = {Lawrence, P.A. and Robinson, J.} } @conference {51240, title = {Managing rangeland soils for C sequestration}, booktitle = {Annual Meeting, American Society of Agronomy}, year = {1998}, month = {October 18-22, 1}, pages = {265-266}, address = {Baltimore, MD}, abstract = {

Rangeland ecosystems are controlled by many factors, of which most important is climate. Other important factors include fire; selective removal of plants and animals; the placement of roads, fences, and watering points; grazing intensity; and agronomic-type practices, such as seeding, fertilizing, and irrigating. Managing soils for C sequestration as organic carbon is very much tied to controlling the type and density of vegetation. The importance of this relationship has been observed where desert grasslands have converted to shrublands, causing wind erosion that removed and redistributed soil organic matter, which in turn reduced nutrient supply, seed bank supply, aggregation, and water holding capacities. Management of inorganic C is less apparent.\  Important questions in this regard include whether soils become a C source rather than a C sink when erosion exhumes petrocalcic horizons, when rangeland soils are irrigated, and when biosolids are added to rangeland soils.

}, author = {Curtis H. Monger and Jeffrey E. Herrick} } @article {51243, title = {Monitoring changes in stressed ecosystems using spatial patterns of ant communities}, journal = {Environmental Monitoring Assessment}, volume = {51}, number = {1-2}, year = {1998}, month = {June 1, 1998}, pages = {201-210}, abstract = {

We examined the feasibility of using changes in spatial patterns of ants-distnbution on experimental plots as an indicator of response to environmental stress. We produced contour maps based on relative abundances of the three most common genera of ants based on pit-fall trap captures. Relative abundance of Conomyrma spp. decreased, relative abundance of Solenopsis spp. increased, and relative abundance of Pogonomyrmex spp. remained relatively unchanged. The contour maps showed long-term changes in foraging activity and/or distribution of colonies of ants in response to grazing by domestic livestock. This study demonstrated that analysis of spatial patterns of ant activity derived from relative abundances of ants in pit-fall traps provided interpretable data for developing an indicator of exposure to ecosystem stress.

}, doi = {10.1023/A:1005939303426}, url = {/files/bibliography/631.pdf}, author = {M. S. Nash and Walter G. Whitford and Justin Van Zee and Kris Havstad} } @conference {51267, title = {Methods for assessing soil aggregation in noncultivated arid and semiarid soils}, booktitle = {Annual Meeting, American Society for Agronomy}, year = {1997}, month = {October 26-31, 1}, pages = {279}, address = {Anaheim, CA}, abstract = {Soil aggregation is increasingly cited as a potentially valuable indicator of a wide variety ecosystem functions based on empirical and echanistic correlations with soil credibility, strength, organic matter accumulation, and biological diversity and activity. An equally wide variety of methods has been used to quantify soil aggregation. This leaves us with the question of whether these results are exchangeable. The method applied to determine soil aggregation should be a reflection of the processes involved at the appropriate spatial and temporal scales. In this paper, we will present guidelines for selecting the appropriate method or methods for the objective of the study. Several methods will be described which are being applied successfully in non-cultivated arid and semi-arid geo-ecosystems to address different specific functions of soil aggregation. Specific attention will be given to the value of soil aggregation as an indicator of sustainability, including ecosystem resistance and resilience.}, author = {Cammeraat, L.H. and Jeffrey E. Herrick and Imeson, A.C.} } @article {51290, title = {Mechanisms for the keystone status of kangaroo rats: graminivory rather than granivory?}, journal = {Oecologia}, volume = {111}, year = {1997}, month = {1997}, pages = {422-428}, abstract = {

Graminivory by kangaroo rats (Dipodomys spp.) was investigated as a potential mechanism for the keystone role of these rodents in the dynamics of desert grasslands. Experiments confirmed that Ord{\textquoteright}s kangaroo rats (Dipodomys ordii) cut and consumed a large proportion of the tillers of three Chihuahuan Desert tussock-forming grass species. Field observations indicated that the characteristically cut grass tillers were absent from all-rodent and medium-sized kangaroo rat exclosures, but were frequent in large-sized kangaroo rat and rabbit exclosures, indicating that the medium-sized kangaroo rats (D. ordii, D. merriami) were responsible for grass cutting. Tiller waste as a percentage of peak standing crop ranged from 7\% in grassland habitats to 0.7\% in Flourensia cernua shrubland. Of the 13 species of perennial, tussock-forming grasses measured, only one, Muhlenbergia porteri, had no tillers cut by kangaroo rats. This study demonstrates that the keystone role of kangaroo rats in Chihuahuan Desert grassland ecosystems is probably the result of their graminivory.

}, keywords = {Chihuahuan Desert, Dipodomys, graminivory, Grass populations, keystone species}, doi = {10.1007/s004420050254}, url = {/files/bibliography/591.pdf}, author = {G. I. H. Kerley and Walter G. Whitford and F. R. Kay} } @proceedings {51292, title = {Modeling effects of spatial pattern, drought, and grazing on rates of rangeland degradation: A combined Markov and cellular automaton approach}, year = {1997}, note = {//??//LTER-III//ProCite field[6]: In}, month = {1997}, pages = {211-230}, publisher = {Lewis Publishers}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, drought, model, grazing, model, model, drought, model, grazing, model, Markov, model, spatial pattern, proceeding, proceedings, rangeland degradation}, author = {Harbin Li and J. F. Reynolds}, editor = {Quattrochi, D.A. and Goodchild, M.} } @article {51298, title = {Modularity and genericness in plant and ecosystem models}, journal = {Ecological Modelling}, volume = {94}, year = {1997}, note = {//??//LTER III//}, month = {1997}, pages = {7-16}, abstract = {

In this paper, we present definitions of modularity and genericness that are based on sets of criteria and rules for model design and which encompass the goal of developing an efficient and flexible structure for plant and ecosystem models. Model structure should be based on modules that (1) relate directly to real world components or processes; (2) have input and output variables that are measurable values; and (3) communicate solely via these input and output variables. Such a model structure has the advantage that it can be incrementally improved by simply replacing one module with another that has the same input and output variables. The underlying mechanism in the replacement module can be different, which facilitates the incorporation of the latest experimental research results and allows modelers to readily test alternative hypotheses about mechanisms. Thus, modularity and genericness open models to contributions from many authors, facilitate the comparison of alternative hypotheses, and extend the life and utility of simulation models.

}, keywords = {article, articles, ecosystem, model, journal, journals, model, ecosystem, model, plant, plant, model}, doi = {10.1016/S0304-3800(96)01924-2}, url = {files/bibliography/JRN00247.pdf}, author = {J. F. Reynolds and Acock, B.} } @article {51309, title = {Mutual exclusion by dolichoderine ants on a rich food source}, journal = {Southwestern Naturalist}, volume = {42}, number = {2}, year = {1997}, month = {1997}, pages = {229-231}, abstract = {

Some species of ants recruit rapidly to rich food sources and may exclude other species from that food source (Holldobler and Wilson, 1990). These ant species interfere with other ant species by using chemical repellents or by physical means. For example, the dolichoderine ant Fornelius pruinosus usually displaces the formicine honeypot ants, Myrmecocystus spp., at food baits (Holldobler, 1982). Interference competition should be most intense where densities of ant colonies are high and when food reserves are limited.

}, keywords = {ant colonies, ant species, chemical repellents, food baits, food reserves, food source, formicine, Fornelius pruinosus, honeypot ants, Interference competition, Myrmecocystus spp., physical dolichoderine ant}, url = {/files/bibliography/599.pdf}, author = {Justin Van Zee and Walter G. Whitford and W. E. Smith} } @conference {51315, title = {A multiple objective decision approach with application to rangeland health}, booktitle = {52nd Annual Conference, Soil and Water Conservation Society}, year = {1997}, month = {July 23, 1997}, address = {Toronto, Canada}, abstract = {A multiple objective decision methodology is proposed, described for evaluating watershed or ecosystem management with respect to both economic and environmental criteria. A proposed structure for determining a Rangeland Health Index will be presented and the methodology will be illustrated for a rangeland watershed in the southwestern United States. A simple algorithm based on linear and dynamic programming principles is presented that allows one to quickly compute the possible range of overall indicator value from the most optimistic to the most pessimistic (best to worst). The method is applied in the context of a hierarchical arrangement of the individual indicators or attributes. The overall or Total Indicator Value is computed without the need to specify or determine explicit weights on the individual ecosystem indicators. The decision tool is particularly useful for examining land areas from numerous, often conflicting, decision making viewpoints or by multiple decision makers. Changes to the priority order of the criteria or attributes at any level of the decision hierarchy can be made and the effect on the Total Indicator Value examined. Soil stability and watershed function, biodiversity, and animal production are major categories of indicators of rangeland health. The impact on the computation of a Rangeland Health Index of emphasizing the importance given to each of these areas over the others is examined.}, keywords = {decision approach, multiple, objective, rangeland health}, author = {Yakowitz, D. S. and M.A. Weltz and Jeffrey E. Herrick} } @conference {51318, title = {Mycorrhizal similarities of septate fungal root endophytes in native plant species of arid ecosystems}, booktitle = {International Conference on Mycorrhizae}, year = {1996}, month = {1996}, abstract = {

Levels of fungal colonization in the roots of fourwing saitbush Atriplex canescens and other dominant native grass and shrub species from an arid ecosystem have been studied. It was shown that colonization by septate fungal colonization was 2.7 times greater fourwing saltbush than colonization by VAM fungi. Historically studies have focused on the role of VAN fungi and how they affect the plant. The septate fungi hear several asimilarities to other types of mycorrhizae. They formed extensive non-dest ve interfaces, primarily by vegetative hyphae, within the root cortex. They enhance nutrient uptake at low concentrations and restrict uptake at high concentrations. They also protect against high salt concentrations. Some are competent decomposers and appear to enhance seedling vigor and establishment by supplying nutrients from external organic matter. They modify soil by binding sand particles to the root surface. We propose that septate fungal endophytes have a major function in ecosystem, processes.

}, url = {/files/bibliography/470.pdf}, author = {J.R. Barrow and McCaslin, B D. and Curtis H. Monger and Feder, I.} } @article {51368, title = {Modelling whole-plant allocation in relation to carbon and nitrogen supply: Coordination versus optimization: Opinion}, journal = {Plant and Soil}, volume = {185}, year = {1996}, note = {//??//LTER-III//}, month = {1996}, pages = {65-74}, abstract = {

One of the few integrating theories related to allocation is the hypothesis of optimization. While optimization theory has great heuristic appeal and has been used to describe a range of physiological and ecological phenomena, it has major limitations. Optimization is necessarily based on a definite time integral and an optimal control strategy must be specific to the same patterns exhibited by the driving variables over this same period of time. Optimization tends to employ the use of oversimplifications in order to facilitate analytical solutions to the optimal control strategy, i.e. the mechanism governing the response of plants, which is the critical issue of interest. It is difficult to define objective criteria that can account for the natural variability in plants and testing the quantitative predictions of optimality models is also difficult. Thus, we suggest that optimization theory is too limited for practical use in modelling whole plant allocation. In this paper, we introduce the use of coordination theory as a practical alternative. We develop a simple plant growth allocation model using both coordination and optimization approaches and show that coordination theory is easily applied, produces results that are quantitatively similar to optimization, and overcomes the inherent limitations of optimization theory.

}, keywords = {article, articles, carbon, model, journal, journals, model, resource allocation, nitrogen, model, plant, model}, doi = {10.1007/BF02257565}, url = {files/bibliography/JRN00211.pdf}, author = {J. F. Reynolds and J. Chen} } @proceedings {51379, title = {Maintaining soil processes for plant productivity and community dynamics}, volume = {II}, year = {1996}, month = {1996}, pages = {33-37}, abstract = {

Rangeland soil biota affect soil properties and processes that control the availability of water and nutrients that are essential for the maintenance of productivity and vegetation composition. oil processes mediated by soil biota include decomposition, nutrient immobilization and mineralization, storage and release of water and nutrients, nitrogen fixation and denitrification, production of plant growth factors and nutrient uptake by mycorrhizae. oil biotic processes control aggregate creation and maintenance, soil macropore formation, and spatial-temporal patterns of soil organic matter and nutrients.

}, keywords = {community dynamics, plant productivity, soil processes}, author = {Walter G. Whitford and Jeffrey E. Herrick} } @article {JRN54978, title = {A Microcomputer-Based Alpine Snow-Cover Analysis Sytem (ASCAS)}, journal = {Photogrammetric Engineering \& Remote Sensing}, volume = {61}, year = {1995}, month = {12/1995}, pages = {1475-1486}, chapter = {1475}, abstract = {

The paper describes the design of an Alpine Snow-Cover Analysis System (ASCAS) for monitoring snow-cover variations in mountainous regions. In addition to observation of snow-cover variations, the system permits derivation of interrelationships between snow cover and regional climate variable. ASCAS integrates several software modules, including image processing, geographic information systems (GIS), snow volume and runoff calculations, scientific visualization, and creation of a database. Problems involved with integrating the different modules into ASCAS and of transferring data from one module to another are discussed. Special attention is given to the necessary hardware because the integrated system is run on microcomputers. In a second part of the paper, a case study for the hydrological year 1990 show first results of simulating snowmelt runoff using the Snowmelt Runoff Model (SRM) and of calculating snow-water equivalent for three basins in the Swiss Alps. In this study, the calculations show that the accumulated snow volume is less in the Inn/Martina basin that in the other two basins (Rhine/Felsberg and Ticino/Bellinzona) because it is drier as a result of it being a continentally influenced inner-alpine valley. Based on a temperature-increase scenario of +2{\textdegree}C in the Inn/Martina basin, the effects of climate change on ablation and runoff are estimated. Ablation occurs two to three weeks earlier than under present conditions, and runoff occurs about three weeks eerier, resulting in an earlier and higher snowmelt peal flow and a steeper recession flow in summer. \ 

}, url = {files/bibliography/Rango1995-06.pdf}, author = {Baumgartner, Michael F. and A. Rango} } @article {51396, title = {Management of mesquite, creosotebush, and tarbush with herbicides in the northern Chihuahuan Desert}, year = {1995}, month = {1995}, pages = {53 }, abstract = {

Two of the major concepts used to describe sustainability in agriculture are to keep land productive for the long term and to improve our basic resources (Box 1994). One of the primary concerns is to prevent an increase in desertification. The judicious use of herbicides is a principal method to reduce further degradation of, and improve, rangelands in the Chihuahuan Desert. Mesquite, creosote bush, and tarbush (scientific names of plants

}, url = {/files/bibliography/447.pdf}, author = {C.H. Herbel and W. L. Gould} } @proceedings {51429, title = {Morphological variation in creosotebush, Larrea tridentata: effects on ecosystem properties}, volume = {Gen. Tech. Rep. INT-GTR-338}, year = {1995}, note = {//NMSU//NONE, LTER//ProCite field[6]: InProCite field[8]: Compilers}, month = {1996}, pages = {195-198}, publisher = {U.S. Department of Agriculture, Forest Service, Intermountain Research Station}, address = {Las Cruces, NM}, abstract = {

Morphological characteristics of creosotebush canopies (angle of exterior stems), size of litter layer and sub-canopy soil chemistry were measured on several sites on the Jornada Experimental Range. Soils under canopies of inverted cone shaped shrubs had little or no litter layer and significantly lower total soil nitrogen and soil carbon than soils under canopies of hemispherically shaped shrubs. In Death Valley, creosotebushes growing in braided washes were predominantly inverted cone shaped. The morphological characteristics of creosotebushes appear to vary with soil type and with mean annual rainfall. The proportional distribution of different morphotypes of creosotebush affects the heterogeneity of creosotebush dominated ecosystems.

}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, Larrea, morphology, precipitation, shrub morphology, proceeding, proceedings, shrub, morphology, soil, shrub morphology}, url = {/files/bibliography/506.pdf}, author = {Walter G. Whitford and E. Martinez-Meza and A.G. de Soyza}, editor = {J.R. Barrow and McArthur, E.D. and R. E. Sosebee and R. J. Tausch} } @conference {51446, title = {Management for rehabilitation of degraded arid ecosystems}, booktitle = {The Wildlife Society Meeting}, year = {1994}, month = {1994}, pages = {Abstract 40}, abstract = {Management strategies for rangelands based on components of succession theory are too simplistic and ineffective. We are now developing more dynamic interpretations of rangelands that incorporate components of lag effects and threshold, importance of episodic events, and multiple stable states and trajectories of vegetation change. These models defy traditional approaches to management, especially regarding improvement of specific resource components. Coupled with increased regulatory restrictions and volatile economics, these new theories force us to revise both our approaches to management and our expectations for the resource. Often we must now admit that restoration, in its narrowest sense the complete return of a site to a pre-existing state, is not a feasible alternative. Our vegetative goals are more appropriately toward rehabilitation, defined as the repair of blocked or damaged ecosystem functions. In the Southwest, desert grasslands have shifted to shrub dominance due to one or more allogenic factors. However, shrub persistence in this region derives from autogenic factors. Our options for rehabilitating stable, shrub-dominated vegetative states are seriously limited, both ecologically and economically. Management efforts need to be directed toward areas that are either in transition or at critical thresholds. In these areas our management practices need to be minimal and silected for their ability to generate cascading effects post-treatment. We have these general tools, but they need to be linked with an ability to detect thresholds, and recognition (and agreement) of functions that need to be repaired.}, author = {Kris Havstad} } @proceedings {51487, title = {Managing New Mexico rangelands for sustained use through the 21st century}, volume = {2}, year = {1993}, month = {1993}, pages = {855-864}, abstract = {New Mexico is rangeland state. Typically viewed as desert or wasteland, it is more accurate to describe the state as primarily a type of land that grows a wide variety of native shrubs and herbaceous vegetation. New Mexico is characterized by climatic and physical limitations (such as peiodic drought and low soil fertility). and has had an extensive history of grazing use by native herbivores. These rangelands generally deteriorated during the latter part of the 19th century. Users of these natural resources frequently misjudged or failed to recognize resource limitiations, which are more severe than for rangelands of the midwest or pastures of the southern and eastern U. S. Resource conditions have improved during the 20th century, but debates over conflicting uses of New Mexico ranelands have grown contentious. At the center of this conflict is the traditional use of rangeland for production of livestock, an annual one billion dollar industry within the state. Yet, livestock grazing is frequently perceived as a nonsustainable use. For example, a common perception is that improved resource conditions have typically been achieved by repeated uses of herb-icides to control unwanted shurbs that are a result of overgrazing. This view has som validity. However, natural resource conser-vation requires active management. Our environment is changing due to both natural causes and human-induced impacts. We have to be involved in resource management bother to mitigate our impacts and sustain renewable resources. Other than federal and state government agencies, the primary managers of New Mexico{\textquoteright}s natural rangeland resources are the graziers. Unless the New Mexico populace is willing to substanitally increase government involve-ment in land stweardship, an involement which would primarily be fundedat the state level, the livestock idunstry must continue to be looked to for management not only of forage for domestic animals, but wildlife habitats, waterhseds and various other natural resources. Principles of livestock management exist, and when applied these principles can guide sustained productions form rangelands and conservations of renewable resources. The public should (1) direct development of appropriate incentives that reward progressive management, and (2) establish common resource objectives for the good of the entire state in partnership with the livestock industry. Through partnership with agriculturalists New Mexico can lead the West in attaining and practicing multiple use of its principle natural resources, its rangelands.}, url = {/files/bibliography/406.pdf}, author = {Kris Havstad and Fowler, J.M.} } @book {51542, title = {Modeling the contributions of decomposer fungi in nutrient cycling}, series = {The Fungal Community: Its Organization and Role in the Ecosystem}, year = {1992}, note = {//OTHER//LTER II//Listed in LTER3 proposal as citing LTER2 support//ProCite field[6]: In}, month = {1992}, pages = {691-714}, publisher = {Marcel Dekker}, organization = {Marcel Dekker}, edition = {Second Edition}, address = {Boston, Massachusetts}, abstract = {Natural and agricultural ecosystems contain complex fungal communities consisting of many species, interacting in many ways to help define the "character" of these systems. Saprotrophic fungi play key roles in nutrient cycling processes within these ecosystems...as they are the principal decomposers of recalcitrant compounds, e.g., lignocelluloses..., and compete with other heterotrophs and plants for energy and nutrients... Nevertheless, their precise roles in these processes remain unclear because making such assessments are difficult and relevant data are limited. How then, can we begin to elucidate their various roles and contributions? Three major fields of research provide us with a basis for addressing this question.... The first consists of observations and experimental research examining the physiological and autecological attributes of fungi. Most of this research focuses on individual species or pure cultures, although studies of the interactions between species are also available. A second field examines fungal growth processes, including the development of simulation models. These efforts include many levels of detail and, again, mostly focus on isolated species. The third area concerns decomposition processes and the construction of representative models, but rarely identify fungi as an independent component. Together, these three fields of research cover the basic concepts needed to initially describe the roles of saprophytic fungi in nutrient cycling processes. It remains to develop a complete conceptualization of this information. In cases such as these, mathematical models are valuable research tools that can help organize data into an overall synthesis. The process of developing a model tests our understanding of the system, identifies areas of uncertainty and, importantly, provides a means of examining alternative conceptual frameworks. The resulting model then serves as a "working hypothesis" that can be quantitatively as well as conceptually tested for validity. Many models have been constructed to simulate either decomposition processes or fungal growth dynamics, but as Paustian (1985) noted, a major conceptual gap exists between these two foci. The principal objectives of this chapter are to: 1) summarize background information relevant to modeling fungal contributions to nutrient cycling and 2) evaluate the few pioneering modeling studies that include both perspectives.}, keywords = {book, books, chapter, chapters, decomposition,fungal, fungal decomposition, model,fungal decompostion, nutrient cycling,fungal decomposition, report, reports, simulation,fungal decomposition}, author = {Daryl L. Moorhead and J. F. Reynolds}, editor = {Carroll, George C. and Wicklow, Donald T. (eds.)} } @article {51544, title = {Modeling the effects of elevated carbon dioxide on plants: extrapolating leaf response to a canopy}, journal = {Journal of Agricultural and Forest Meteorology}, volume = {61}, year = {1992}, note = {//OTHER//NONE//}, month = {1992}, pages = {69-94}, keywords = {article, articles, carbon dioxide,model, journal, journals, model,carbon dioxide, plants,carbon dioxide model}, author = {J. F. Reynolds and J. Chen and Harley, P. C. and Hilbert, D. W. and Dougherty, R. L. and Tenhunen, J. D.} } @article {51582, title = {Microbial precipitation of pedogenic calcite}, journal = {Geology}, volume = {19}, year = {1991}, note = {//LOCAL//NONE//}, month = {1991}, pages = {997-1000}, abstract = {Pedogenic calcite in desert soils has become increasingly important as an indicator of paleoclimate, landscape stability, and landscape age. This study indicates that calcic and petrocalcic horizons in desert soils are not simply the result of inorganic precipitaion of calcite. Soil microorganisms were found to be involved in calcite precipitation in a typical desert soil near Las Cruces, New Mexico. Fossilized remains of calcified fungal hyphae and Microcodium stuctures are abundant in the petrocalcic horizon. Soil bacteria and fungi precipitated calcite when cultured on a Ca-rich medium. In an experiment where soil columns were irrigated with Ca-rich solutions, calcite formed in soils containing soil microorganisms, but no calcite formed in sterile soils. Thus, biomineralization of calcite by soil microorganisms appears to be an important mechanism of unknown magnitude.}, keywords = {article, articles, bacteria, calcite formation, calcite, formation, caliche, also SEE , geomorphology, calcite formation, journal, journals, soil, calcite formation}, author = {Curtis H. Monger and LeRoy A. Daugherty and W. C. Lindemann and Liddell, Craig M.} } @article {51583, title = {A microscopic examination of pedogenic calcite in an aridisol of southern New Mexico}, year = {1991}, note = {//LOCAL//NONE//ProCite field[6]: In}, month = {1991}, pages = {37-60}, institution = {Soil Science Society of America}, address = {Madison, Wisconsin}, abstract = { Thin section analysis of pedogenic calcite was made for a mid-Pleistocene Aridisol in southern New Mexico. The 4.5 m thick pedon was divided into eight zones of pedogenic calcite accumulation. The macromorphology of the eight zones includes Stage I filaments and coatings, Stage II and Stage III nodules and internodular fillings, and a petrocalcic horizon consisting of a Stage IV laminar zone and plugged horizon. Thin sections were make of oriented peds from each of the eight zones and revealed the following. Filaments consist of calcite crystals on roots and calcite-impregnated pore walls (hypo-coatings). Nodules contain framework grains embedded in a matrix of micritic calcite (micrite); harder nodules contain denser and more coalescent micrite than softer nodules. Internodular fillings contain calcitans and micrite that is loosely disseminated in voids. The laminar zone consists of Microcodium, framework grains packed between relatively pure micritic laminae, and sparry calcite in voids. The plugged horizon is composed of widely spaced framework grains embedded on a dense micritic matrix and calcified fungal fillaments in voids. Corroded framework grains are common in both the laminar zone and plugged horizon and reflect dissolution of the grains. Argillans in calcareous zones have been partly or wholly obliterated by calcitans.}, keywords = {book, books, calcite, calcium carbonate, also SEE , caliche, chapter, chapters, geomorphology, calcite, report, reports, soil, calcite}, isbn = {Special Publication no. 26}, author = {Curtis H. Monger and LeRoy A. Daugherty and L. H. Gile} } @article {51664, title = {Matric potential of clay loam soils on arid rangeland in southern New Mexico}, journal = {Journal of Range Management}, volume = {42}, number = {5}, year = {1989}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {September 1, 198}, pages = {386-392}, abstract = {

The matric potential of soil water is presented for 6 clay loam sites on floodplains of arid rangelands. Gypsum resistance blocks impregnated with plaster of paris were placed at 6 soil depths to 122 cm. At 4 locations, blocks were placed inside and outside a buried sheet metal cylinder so that estimates could be obtained of matric potential due to precipitation and due to precipitation plus run-in. The average annual precipitation during the approximate 20-year study period was 242 mm, slightly above the long-time average. Haplargids dominated by tobosa [Hilaria mutica (Buckl.)Benth.] had a greater probability of the matric potential>=-1.5 MPa (wet soil) than the Calciorthids dominated by burrograss (Scleropogon brevifolius Phil.). The probability of matric potential>=-1.5 MPa (wet soil) was as great or greater in winter as during the summer growing season. The factors affecting matric potential were amount and nature of precipitation, amount of run-in water, soil and vegetation type, position on the landscape, and microrelief.

}, keywords = {precipitation, probabilities, soil matric potential, soil texture}, doi = {10.2307/3899545 }, url = {/files/bibliography/345.pdf}, author = {C.H. Herbel and Gibbens, Robert P.} } @proceedings {51667, title = {Managing sheep to optimize profit}, year = {1989}, month = {1989}, pages = {17-32}, address = {Louisville, KY}, abstract = {

Sheep production is one of the oldest human agricultural enterprises. Management techniques for improving performance date from the earliest flocks. In the beginning and for hundreds of years, improvements in management were entirely dependent on the observational skill or "eye of the shepherd." Fifty years ago, fall-lambing was limited mostly to Dorset sheep. Range sheep operators wanted only one lamb per ewe. Most of the extra lambs were sacrificed and ewes were not bred before they were 18 months of age. A sick sheep was considered a dead sheep.

}, url = {/files/bibliography/349.pdf}, author = {Clarence V. Hulet} } @article {51678, title = {Mechanisms of surface litter mass loss in the northern Chihuahuan Desert: a reinterpretation}, journal = {Journal of Arid Environments}, volume = {16}, year = {1989}, note = {//??//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1989}, pages = {157-163}, abstract = {

A re-examination of surface litter decomposition studies in the northern Chihuahuan desert (New Mexico, U.S.A.) suggests mass loss patterns may be more closely regulated by abiotic precesses than originally thought. Although biological mechanisms have been proposed to explain the high rate of surface litter disappearance in this ecosystem, non-biological processes, such as the leaching of solubles and photochemical degradation of lignins, may account for much of the total loss. Results of some recent studies may be better explained when the probable contributions of abiotic factors are considered.

}, keywords = {abiotic processes,decomposition, article, articles, decomposition, abiotic processes, decomposition,lignin, decomposition,litter, journal, journals, lignin,decomposition, litter,decomposition}, doi = {10.1016/S0140-1963(18)31022-X}, url = {files/bibliography/JRN00101.pdf}, author = {Daryl L. Moorhead and J. F. Reynolds} } @article {51685, title = {The microarthropod fauna associated with a deep rooted legume, Prosopis glandulosa, in the Chihuahuan Desert}, journal = {Biology and Fertility of Soils}, volume = {7}, year = {1989}, note = {//NMSU, USDA//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1989}, pages = {330-335}, abstract = {

The rhizosphere microarthropod fauna of a woody, deep-rooted legume, Prosopis glandulosa, was sampled at four sites in the northern Chihuahuan Desert and compared with the rhizosphere microarthropod fauna of a co-dominant shrub, Larrea tridentata. Prostigmatid mites (Speleorchestes sp., Neognathus sp., Rhagidia sp., Tydaeolus sp., Steneotarsonemus sp., Tarsonemus sp., Nanorchestes sp., Gordialycus sp.), the cryptostigmatid mites (Bankisonoma ovata and Passalozetes neomexicanus), the mesostigmatid (Protogamasellus mica), and the collembolan (Brachystomella arida) characterized the fauna at depth greater than 1 m. Microarthropods were recovered from soils at a depth of 13 m at the edge of a dry lake and at depths of 7 m in a dry wash which were pre-European man P. glandulosa habitats. In habitats where P. glandulosa is a recent invader, root depth and microarthropods were less than 3 m. In most habitats, population densities of microarthropods at depth \<0.5 m were more than 100 times those at depths \>0.5 m. Population densities of microarthropods associated with P. glandulosa growing at the edge of a dry wash were not significantly smaller at 0.5-1.0 m depth than at 0-0.5 m. The deep-rhizosphere microarthropod fauna is a reduced subset of the fauna of surficial soils, suggesting that this fauna plays a role in decomposition and mineralization processes functionally similar to that of microarthropods in surficial soils.

}, keywords = {article, articles, collembola,Prosopis, journal, journals, mesquite community,rhizosphere, microarthropod,Prosopis, Prosopis, rhizosphere, Prosopis,microarthropods, rhizosphere,Prosopis}, doi = {10.1007/BF00257828}, url = {files/bibliography/89-BioFertofSoils-Whitford.pdf}, author = {Solange Silva and Walter G. Whitford and W. M. Jarrell and R. A. Virginia} } @conference {51720, title = {The matric potential of water regimes of clay loam soils on arid rangelands of southern New Mexico}, booktitle = {41st Annual Meeting, Society for Range Management}, year = {1988}, month = {1988}, pages = {31}, author = {C.H. Herbel and Gibbens, Robert P.} } @proceedings {51835, title = {Managing ewes for more lambs}, year = {1986}, month = {1986}, pages = {76-78}, abstract = {

Studies have clearly demonstrated that the best way to increase profitability in the sheep business is to increase the number of lambs born per lambing. It is then obvious the more of these additional lambs that survive to market weight, and the more quickly they reach that weight, the more profitable they will be, in most cases. This presentation will be limited to the first two of these three important factors affecting sheep production profitability.

}, url = {/files/bibliography/298.pdf}, author = {Clarence V. Hulet} } @article {51880, title = {Mesquite (Prosopis glandulosa Torr.) dunes and interdunes in southern New Mexico: A study of soil properties and soil water relations}, journal = {Journal of Arid Environments}, volume = {9}, year = {1985}, note = {Full Article from Journal of Arid Environments posted on this website with permission from Elsevier. http://www.sciencedirect.com/science/journal/01401963}, month = {1985}, pages = {27-38}, abstract = {

Soil properties and soil water relations were compared between soils of mesquite (Prosopis glandulosa Torr.) dunes and soils of adjacent interdune areas in southern New Mexico. Particle size, bulk density, organic matter content, electrical conductivity, pH, and temperature of dunal and interdunal soils were measured. Except for particle size and temperature, dunal and interdunal soils did not differ greatly. Soils of dunes had more sand and less silt and clay than did soils of interdunes. Soil temperatures were higher in interdunes than in vegetated dunes. Soil temperatures were similar in dunes with plant cover removed and in interdunes. Infiltration and runoff, hydraulic conductivity, and water retention measurements showed that although dune soils had greater infiltration and more rapid hydraulic conductivity, interdune soils retained more water above -1{\textperiodcentered}5 MPa matric potential. Evaporative losses, as measured with atmometers 3 cm from the soil surfaces, were greater from interdunes than from vegetated dunes. Through two growing seasons, measured total soil water content at a depth of 30{\textperiodcentered}5 cm was always greater for interdunes than for either vegetated or bare dunes. The dune soils stored water less efficiently than interdune soils and reached -1{\textperiodcentered}5 MPa matric potential with much greater frequency.

}, url = {/files/bibliography/277.pdf}, author = {J.T. Hennessy and Gibbens, Robert P. and J.M. Tromble and Manual Cardenas} } @book {51888, title = {Microcomputer simulation of soil erosion in desert grasslands}, series = {Modelling and Simulation on Microcomputers}, year = {1985}, note = {//USDA//NONE//ProCite field[6]: In}, month = {1985}, pages = {149-152}, publisher = {Society of Computer Simulation}, organization = {Society of Computer Simulation}, address = {La Jolla, California}, abstract = {A long-term ecological monitoring of desertification trends in grasslands of the northern Chihuahuan Desert was established as part of the USDA/SEA Antidesertification program. Five study areas were located on the Jornada Experimental Range, Otero Mesa and the Peloncillo Mountains in New Mexico, Big Bend National Park in Texas, and Rancho La Campana in Mexico. A high precision auto-level was used in 1982 and 1983 to establish baseline data on the current soil-surface level along permanent 30 m transects in these study areas. In the future, remeasurement of these transects should provide data on rates of soil erosion. This data could then be used to validate models used to predict rates of soil erosion. The Universal Soil Loss Equation (USLE) has been used to make such predictions. In this paper a microcomputer version of the USLE model is presented and applied to data from Big Bend National Park.}, keywords = {book, books, chapter, chapters, erosion, SEE (soil), model, soil erosion, report, reports, soil erosion, model}, author = {J. Ludwig}, editor = {Lavery, R. G. (ed.)} } @article {51897, title = {Microarthropods of a desert tabosa grass (Hilaria mutica) swale}, journal = {The American Midland Naturalist}, volume = {114}, year = {1985}, note = {//NMSU//LTER I//}, month = {1985}, pages = {225-234}, abstract = {

We examined soil microarthropod populations inhabiting a clay-silt soil of a tabosa grass (Hilaria mutica) swale in southern New Mexico.... Overall densities of microarthropod groups were correlated with soil moisture but many individual taxa were not. The most numerous and frequently occurring taxa [nanorchestid, tydeid and bdellid mites (Progtigmata); Aphelacarus sp. and Cosmochthonius sp. (Cryptostigmata)] are common in all Chihuahuan desert habitats examined to date and are common in other North American desert areas.

}, keywords = {arthropod, SEE , article, articles, grass,tobosaHilaria, Hilaria swale,microarthropods, journal, journals, microarthropod,Hilaria swale}, url = {files/bibliography/85-AmMidNat-Whitford.pdf}, author = {Yosef Steinberger and Walter G. Whitford} } @article {51911, title = {Manipulative range improvements: Summary and recommendations}, year = {1984}, month = {1984}, pages = {1167-1178}, institution = {Westview Press}, address = {Boulder, CO}, abstract = {

Largely because of past federal policies, grazing practices, and the climate. most western public rangeland is in a degraded condition. Professional opinion remains divided on whether \ range condition has improved or deteriorated over the last 50 years;\  however, there is a consensus that vast areas need immediate attention. Some rangeland is dominated by woody vegetation and undesirable species of annual grasses rather than the perennial grasses and forbs preferred for livestock grazing. However, because the woody plants are long lived, manipulation of grazing intensity (or cessation of grazing) alone will not restore the rangeland. To increase livestock production on this rangeland, it may be necessary to manipulate the present vegetation by mechanical, chemical, or biological means.

}, url = {/files/bibliography/259.pdf}, author = {C.H. Herbel} } @article {51932, title = {A mechanical animal-powered cow spacer}, journal = {Journal of Range Management}, volume = {36}, number = {4}, year = {1983}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {July 1, 1983}, pages = {542-543}, abstract = {With the integration of electronic and mechanical devices, accurate, automatic data acquisition systems are used in agriculture research with animals. Fiby et al. (1979) reported that weight data were lost because cows bunched together as they moved over the weighing platform. To control the tendency for cattle to follow each other (Grandin, 1980) and alleviate bunching, we developed a low-cost, practical, easy-to-build, low-maintenance device to space individual animals as they move single file through a chute. The mechanical animal-powered cow spacer is one component of an automatic, electronic weighing/identification system now used to monitor individual weight changes of cattle grazing semidesert rangeland on daily basis (Anderson et al., 1981). The cow spacer would also be effective in commercial operations in which automatic spacing of animals is desirable.}, keywords = {animal-powered, automatic spacing, cow spacer, mechanical}, url = {/files/bibliography/228.pdf}, author = {D.M. Anderson and Mertz, D.L.} } @article {51941, title = {Mesquite age and size in relation to dunes and artifacts}, journal = {The Southwestern Naturalist}, volume = {28}, year = {1983}, note = {//NMSU//NONE//}, month = {1983}, pages = {89-94}, abstract = {In a duneland dominated by mesquite (Prosopis glandulosa var. torreyana) twelve mesquite-dune complexes were analyzed in order to determine relationships between plant age, plant canopy size, and dune size. In addition, surface Indian artifacts were measured along the study transect which centered through remnants of an Indian campsite. These data were collected in an attempt to investigate the theory that mesquite is at least partially responsible for the initiation and continuation of the dune building process in the Jornada Plains. Plant age was significantly related to the volume of the plant canopy, and to the volume of the dune. Surface artifact densities tended to be highest in areas of greater dune formation, which suggests that artifacts are more visible in areas of greater soil erosion. The ring numbers, taken from these samples do support earlier observations that there has been a recent and rapid increase of mesquite on the Jornada Plains.}, keywords = {archeology,dunes \& artifacts, article, articles, artifacts, Prosopis dunes, journal, journals, mesquite dune, SEE , plant, Prosopis, Prosopis dunes, artifacts, Prosopis, age}, author = {Gadzia, Jimi S. Graham and J. Ludwig} } @mastersthesis {51964, title = {Mathematical approach to range condition in comparison to the SCS method}, year = {1983}, note = {//NMSU//NONE//}, month = {1983}, pages = {189}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {In the USA, the Soil Conservation Service (SCS) method of range condition classification which relates the current state of health of development stage of rangeland to the potential of which the area is capable has been widely used. The application of the method, however, presupposes that the potential plant community be known. That is not always possible for many rangelands in the world where the deterioration has been such as to almost prelude any determination of the potential plant community. This study aimed at investigating an alternative approach to rangeland classification.... The variation of the mean production of the group as well as the mean production of some major plant species across the three condition classes and seral stages of the two grouping procedures (SCS and cluster) had an approximately similar trend. The cluster analysis, however, appeared to better classify these plant communities. The pairwise squared generalized distance between groups and the average production within each group were clearly distinct with the cluster procedure. Seven transects out of one hundred and twenty (5.33\%) were misclassified by the cluster procedure while thirty-four (28.33\%) were misclassified by the SCS method. Cluster analysis associated with multiple discriminant analysis produced the best ecologically significant grouping.}, keywords = {dissertation, dissertations, productivity, range condition, range condition, rangeland,condition classification, technique, cluster procedure, technique, range condition classification, theses, thesis}, author = {Pamo, Etienne Tedonkeng} } @proceedings {52027, title = {Manipulating rangeland forage quality with the grazing animal}, year = {1981}, note = {Reproduced by kind permission of CSIRO PUBLISHING, Melbourne Australia, from Forage evaluation: concepts and techniques: proceedings of a workshop entitled {\textquoteright}Forage evaluation and utilization - an appraisal of concepts and techniques{\textquoteright}held in Armidale, N.S.W., 27-31 October, 1980, under the auspices of the U.S./Australia Cooperative Science Program / editors: J.L. Wheeler, R.D. Mochrie. Published jointly by CSIRO Australia and the American Forage and Grassland Council, 1981.}, month = {1981}, pages = {313-328}, address = {Armidale, NSW, Australia}, abstract = {

The positive balance that evolved between plants and grazing animals is not maintained under continuous grazing. Optimum production from the plant:grazing-animal system can be realized from only high leaf:stem and green:dead ratios in both the standing crop and animal diets. If we are to realize optimum production, we will need grazing methods in which time of year, frequency, and duration of defoliation can be controlled for individual plants and still permit high animal selectivity. By constructing more paddocks, stocking density can be increased and the extent of defoliation on individual plants can be manipulated. High individual animal production and proper individual plant defoliation can only be obtained under high stocking density if livestock are frequently moved between paddocks. To accomplish this, paddock design must ensure that animal stress and labor requirements are held to a minimum. However, the added flexibility derived from rotating animals among paddocks substantially increases the management required to obtain high animal performance and proper plant usage.

}, keywords = {continuous grazing, forage quality, grazing methods, optimum production, rotation grazing}, url = {/files/bibliography/193.pdf}, author = {D.M. Anderson} } @article {52031, title = {Mating behavior of Polyphylla diffracta (Coleoptera: Scarabaeidae)}, journal = {The Southwestern Naturalist}, volume = {26}, number = {2}, year = {1981}, note = {//LOCAL//NONE//}, month = {1981}, pages = {215-216}, abstract = {

On 26 Jul. 1969, imagos were observed emerging form an open park near Las Cruces, New Mexico, between 1800 and 2000 h (MST). Males were flying in a zig-zag pattern, 10 to 50 cm above ground level, with their lamellate antennae extended. In three of the 22 copulations observed, males helped the female to dig her way out of the soil. Females emerged briefly, mated, than returned to their emergence burrows and disappeared. Only males were captured at lights, suggesting that females emerge only to mate. On 16 occasions, more than one male was attracted to the emergence hole, resulting in jostling for copulatory positions. After on male successfully engaged the female genitalia, the other males dispersed. Three newly emerging females were captured before copulation and placed in small screen cages. When placed on the ground, each of these cages attracted a minimum of five males within a 5-min time period. Males also landed and investigated emergence holes into which newly mated females had returned. All of these observations support the presence of sex pheromones in Polyphylla diffracta, and suggest that the females mate only once.

}, keywords = {article, articles, insect, Polyphylla, journal, journals, Polyphylla,mating behavior}, doi = {10.2307/3671129 }, url = {files/bibliography/81-SWNtrlt-Whitford.pdf}, author = {Harold G. Fowler and Walter G. Whitford} } @proceedings {52038, title = {Manipulative range improvements--principles and practices}, year = {1981}, month = {1981}, pages = {557-579}, address = {Kuwait City, Kuwait}, abstract = {

Our expanding population is demanding more productivity from our rangelands. Range science is concerned with the plants, animals, soils, and waters on rangelands, and particularly, the interaction of these factors. Native plant communities should only be used as guides to determine site potential. Extensive practices on rangelands include manipulation of animals and burning. Intensive practices include control of unwanted plants, revegetation, and fertilization. When properly conducted, intensive manipulative practices result in much higher production than occurred before treatment.

The most effective method, whether chemical or mechanical, for control of unwanted plants varies with the site, the species, and the degree of infestation. Revegetation may be required where desirable vegetation has been depleted by past grazing abuses, droughts, and encroachments of unwanted plants. Water is generally the primary factor limiting plant growth but when that need has been satisfied, additional plant nutrients such as nitrogen and phosphorus may be useful. Principles and practices of plant control, revegetation, and fertilization are presented. These. more costly practices are riskier and require higher management it1puts, but the potential benefits are great. With changing technology or favorable economic conditions, the range manager may decide to intensify his range improvement efforts.

}, url = {/files/bibliography/199.pdf}, author = {C.H. Herbel} } @article {52087, title = {Managing semidesert ranges of the Southwest}, year = {1980}, month = {1980}, pages = {48 }, abstract = {Some people call the arid ranges of the Southwest "Big Country." The ranges may seem limitless, but as a renewable resource for livestock grazing, these ranges are fragile, easily damaged by abuse and subject to droughts. Many have already been damaged by a combination of grazing, droughts and a rapid increase of unwanted shrubs. Range managers work to produce the highest possible net return from rangeland while preserving it as a renewable resource. Because each ranch is different, each rancher has to tailor his own management plan to fit his range and his livestock. This publication brings together conclusions from research and experience in the management of Southwestern arid ranges for ranchers to consider as they select management practices for their ranches.}, url = {/files/bibliography/180.pdf}, author = {C.H. Herbel and W. L. Gould} } @proceedings {52099, title = {Modeling Yucca primary productivity: substrate requirements for growth}, year = {1980}, note = {//LOCAL//NONE//ProCite field[6]: In}, month = {1980}, pages = {69-82}, publisher = {Centro de Investigacion en Quimica Aplicada}, abstract = {A preliminary study was conducted to examine the importance of including substrate costs of plant tissue biosynthesis in growth models of Yucca. The biochemical composition of plant tissue form select organs of Y. elata and Y. baccata were determined and used in the Penning de Vries model to compute the necessary substrate (glucose) required for their biosynthesis. Through the use of a simple growth model, it was found that substantial predictive error would be introduced if substrate costs were ignored for plant organs deviating significantly from a simple carbohydrate composition.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, model,Yucca productivity, plant, Yucca, proceeding, proceedings, Yucca,productivity}, author = {J. F. Reynolds and Gary L. Cunningham} } @mastersthesis {52100, title = {Microbial activity of a semidesert rangeland as affected by 2,4,5-T}, year = {1980}, note = {//USDA//NONE//}, month = {1980}, pages = {69}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {The objective of this research was to examine the effect of 2,4,5-T on the soil microflora of a mesquite-infested semidesert rangeland one year after herbicide application. Additionally, several environmental factors were examined to determine their relationship with microbial activity. Carbon dioxide evolution was found to be influenced by soil moisture, soil temperature, and air temperature. Dehydrogenase activity was not found to be affected by field environmental parameters.}, keywords = {decomposition, microbial activity, dissertation, dissertations, herbicide, "2,4,5-T", mesquite dune, microbial activity, microbial activity, mesquite dune, microbial activity,herbicide, theses, thesis}, author = {J. Ryder-White} } @mastersthesis {52128, title = {Milk production, weight changes and preweaning growth rate of Brangus, Hereford and reciprocal crossbred cows under semidesert conditions}, year = {1979}, note = {//??//NONE//}, month = {1979}, pages = {63}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {cattle,breeding, cattle,milk production, cattle,productivity, dissertation, dissertations, theses, thesis}, author = {Richards, Steven Glen} } @mastersthesis {52178, title = {Milk production of Hereford, Brangus and reciprocal crosses and its influence on the preweaning performance of calves}, year = {1977}, note = {//NMSU//NONE//}, month = {1977}, pages = {67}, school = {New Mexico University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Milk production data were collected weekly, using the weight-suckle-weight method, during the last 6 weeks of lactation of 67 beef cows at the College Ranch of New Mexico State University. These cattle were part of the crossbreeding project carried out by the Department of Animal Science and designed to evaluate the performance of Hereford, Brangus and their reciprocal crosses under range conditions. Data used in the present study included milk production, pregnancy status and body weight-change during lactation of the four breeds of cows and adjusted 205-day weight and grade of their respective calves.}, keywords = {cattle, breeding, cattle, milk production, cattle, nutrition, cattle, reproduction, dissertation, dissertations, genetics,milk production, milk production, theses, thesis}, author = {Chinolla-Ruiz, Oscar S.} } @mastersthesis {52180, title = {Milk production and composition, weight changes, and calf growth rate of Brangus, Hereford, and reciprocal crossbred cows under semidesert conditions}, year = {1977}, note = {//??//NONE//}, month = {1977}, pages = {101}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {cattle,productivity, cattle,reproduction, dissertation, dissertations, genetics,cattle, milk production, theses, thesis}, author = {DeMiranda Leite, P. R.} } @mastersthesis {52227, title = {Maternal traits in Brangus cattle}, year = {1975}, note = {//NMSU//NONE//}, month = {1975}, pages = {101}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Production records of two Brangus commercial straightbred herds were used in this research to study the maternal traits of Brangus cattle under semidesert range conditions. Data were collected from a total of 97 cows including 40 cows from Ladder Ranch (herd I), and 57 cows which were born on the College Ranch (herd II) at New Mexico State University between 1965 and 1974. Both reproductive and productive performance traits were studied in terms of calf crop born, weaned, and number of pounds of calf weaned per cow per year. Weaning weight (actual and adjusted at 205 days of age) was considered as the dependent variable, and was assumed to be affected by dam, year, sex of calf at weaning, and fall dam weight as independent variables. Dam, year and age of calf approached a highly significant effect (P<.01) on weaning weights of calves out of both herds, except the 205 day adjusted weaning weight of calves from herd I. The effect of calf{\textquoteright}s sex was highly significant (P<.01) in both herds where actual weaning weight was concerned, and significant (P<.05) in both herds on adjusted weaning weight. Male exceeded females by 40.33 and 23.81 pounds in herd I and 30.0 Dan 15.9 pounds in herd II for actual and adjusted 205 day weaning weights, respectively. Fall dam weight had a highly significant effect (P<.01) on weight of calves from herd II and a nonsignificant effect (P>.05) on weight of calves weaned out of herd dams. Calving intervals were analyzed in two ways: one using only the interval between calves in consecutive years and then by using all intervals. Calving interval was considered to be influenced by dam, year, sex of initial calf, and linear and quadratic effects of calving date of initial calf. Dam had a significant effect(P<.1) on calving interval. Year had a statistically highly significant effect (P<.01) in herd I, and a significant effect (P<.05) in herd II. Sex of calf at side was non-significant (P>.1) for either herd and for either calving interval range. Calf birth date had neither linear or quadratic effects (P>.1) in either herd. Repeatability values of weaning weight and calving interval were estimated. Within herd repeatability values for actual weaning weight for herds I and II, respectively, were 0.3815 and 0.2484. Similar values for adjusted weaning weight were 0.3702 and 0.2484. Pooled estimates were 0.2542 and 0.3522 for actual and adjusted weaning weights, respectively. Within herd and pooled repeatability values of calving interval were zero using only consecutive year calves. For all calves repeatability was 0.203 and zero for herds I and II, respectively, while pooled the pooled value was 0.041. Weight of herd II dams was considered to be influenced by dam, year, season, season x year, and sex of calf and lactation status of dam (dry or wet). Dam weights in the fall were significantly affected (P<.01) by dam, year, season and sex of calf. Season x year interaction was a significant (P<.05) source of variation on weight of dam}, keywords = {cattle, management, cattle, productivity, cattle, reproduction, dissertation, dissertations, theses, thesis}, author = {Cruz-Mendoza, Javier} } @article {52248, title = {Mycorrhizae of desert plants}, year = {1975}, note = {//??//US-IBP//}, month = {1975}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {book, books, chapter, chapters, fungi,mycorrhizae, mycorrhizae, plant mycorrhizae, report, reports}, isbn = {Research Memorandum 75-37}, author = {E.E. Staffeldt and Vogt, K. B.} } @proceedings {52279, title = {Milk production by hereford cows}, volume = {25}, year = {1974}, month = {1974}, pages = {310-312}, abstract = {Weaning weight and percent calf crop are the most important traits affecting net income on a cow-calf ranch. Dams{\textquoteright} milk production is crucially important to preweaning performance of calves. On semidesert grassland, natural forage often limits reproduction and lactation of range cows. Consequently, a part-year confinement program could overcome periods of reduced forage and permit a more flexible ranching operation. The purpose of this experiment was to compare the performance of beef cows as milk producers, the effect of milk consumption on growth of suckling calves and trends in milk composition under range and drylot conditions.}, keywords = {beef cows, calves, grassland, performance, semidesert, weaning}, url = {/files/bibliography/148.pdf}, author = {A. das Neves and Wallace, J.D. and C.H. Herbel} } @mastersthesis {52280, title = {Milk production of Hereford cows}, year = {1974}, note = {//USDA//NONE//}, month = {1974}, pages = {45}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {The performance of Hereford cows was compared under range and drylot conditions. The objectives of this study were to compare (1) milk yield of cows under the two management systems, (2) effect of milk consumption on growth of suckling calves, and (3) trends in milk composition. The experiment was conducted from April 18 to July 24, 1973, and involved 64 lactating cows ranging in age from 3 through 7 years. Cows were stratified by body weight, age group and age of their calves and randomly allotted to the two treatment groups.}, keywords = {cattle, management, cattle, productivity, cattle, reproduction, dissertation, dissertations, theses, thesis}, author = {A. das Neves} } @article {52265, title = {Mourning dove foods in semi-desert, south-central New Mexico}, journal = {Journal of Wildlife Management}, volume = {38}, number = {4}, year = {1974}, note = {//NMSU//NONE//}, month = {1974}, pages = {941-944}, abstract = {The objective of this study was to identify principal foods of mourning doves (Zenaida macroura) in an uncultivated area of south-central New Mexico. Leopold (1921) named some foods in uncultivated areas near Albuquerque, but did not report proportions of the various items eaten. The only other report forma n uncultivated area in New Mexico (Griffing and Davis, 1974) identifies some dove foods in a shrubland in the southeastern corner of the state.}, keywords = {article, articles, Aves, Zenaida, diet, bird, Mourning Dove, food habits, Mourning Dove, journal, journals, Mourning Dove, foot habits}, author = {C.A. Davis} } @article {52273, title = {Managing semidesert ranges of the Southwest}, year = {1974}, month = {1974}, pages = {48 }, abstract = {

Some people call the arid ranges of the Southwest "Big Country." The ranges may seem limitless. But as a renewable resource for livestock grazing, these ranges are fragile, easily damaged by abuse and subject to droughts. Many have already been damaged by a combination of grazing, droughts, and a rapid increase of unwanted shrubs.

Range managers work to produce the highest possible net return from rangeland while preserving it as a renewable resource. Because each ranch is different, each rancher has to tailor his own management plan to fit his range and his livestock.

This publication brings together conclusions from research and experience in the management of southwestern arid ranges for ranchers to consider as they select management practices for their ranches.

}, issn = {456}, url = {/files/bibliography/153.pdf}, author = {C.H. Herbel and Steger, R. and W. L. Gould} } @article {52281, title = {Management implications of herbage weight changes on native rangeland}, journal = {Journal of Soil and Water Conservation}, volume = {29}, year = {1974}, month = {1974}, pages = {227-229}, abstract = {Range researchers and technicians often calculate herbage production from clippings or estimates made once a year, commonly at the {\textquoteright}end of the growing season. Such estimates may lead to serious miscalculations unless seasonal changes in herbage weight and differential growth of individual species and plant parts are recognized. Data from black grama and blue grama vegetation types show that peak herbage weight lasts only a short time and that the amount of herbage available for grazing animals for most of the year is considerably less than that present at the peak. In addition, leaves and inflorescences, which are the most palatable and nutritious plant parts, deteriorate more rapidly during the dormant season than culms, the least palatable and nutritious plant parts. These changes have major implications in determining stocking rates, comparing treatments and years, determining utilization and planning grazing systems.}, url = {/files/bibliography/155.pdf}, author = {Pieper, Rex D. and C.H. Herbel and D.D. Dwyer and Banner, R.E.} } @article {52295, title = {Metabolic rates of millipedes in a desert ecosystem}, year = {1973}, note = {//??//US-IBP//}, month = {1973}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {book, books, chapter, chapters, invertebrate,millipedes, metabolism,millipedes, millipede,metabolism, report, reports}, isbn = {Research Memorandum 73-31}, author = {Crawford, C. S. and Wooten, R. C.} } @article {52356, title = {Meiosis and pollen development in haploid cotton plants}, journal = {Journal of Heredity}, volume = {62}, number = {3}, year = {1971}, month = {May-June 1971}, pages = {139-141}, keywords = {cotton, haploid, Meiosis, pollen}, url = {/files/bibliography/99-007.pdf}, author = {J.R. Barrow} } @article {52418, title = {Moisture and temperature effects on emergence and initial growth of two range grasses}, journal = {Agronomy Journal}, volume = {61}, year = {1969}, month = {1969}, pages = {628-631}, abstract = {This research, conducted in controlled, light-temperature chambers, studied the effects of two temperature regimes and five moisture levels on early growth of black grama [Bouteloua eriopoda (Torr.) Torr.] and boer love-grass (Eragrostis chloromelas Steud.). The maximum daily soil temperatures ranged from 53 to 67C in the high-temperature regime and from 38 to 51 C in the low-temperature regime, depending on moisture level. The daily minimum temperatures were about 25C in all treatments. The five soil moisture levels were determined as a portion of the volume required to maintain field capacity conditions. Level A was approximately field capacity; levels B and C were watered as level A on the planting day and then reduced to about a half and a third of level A for the remainder of the 21-day trial. Levels D and E were watered as Level A for the first 3 days and then reduced to about a half and a third of level A for the remainder of the trial. In the high-temperature regime, black grama did not emerge at moisture levels B and C and boer lovegrass did not emerge at levels B, C and E. In addition, boer lovegrass did not emerge in the low-temperature regime at moisture level C. Survival of emerging seedlings ranged from 0 to 4.7\% in the high-temperature regime at all moisture levels except A. Reduced soil moisture, a day after planting, was more detrimental to survival than reducing soil moisture the third day after planting. Survival of black grama at moisture Level A in the high-temperature regime was not adversely affected by the high leaf temperatures (81C). The shoot lengths and weights of surviving black grama seedlings were always greater than those of boer lovegrass. Survival and growth of seeded species in the Southwest would be enhanced if soil temperatures and evaporation from the soil surface were reduced. Under the conditions of this 21-day trial, it took about 70 mm of water for either species to survive in the low-temperature regime and about 231 mm to survive in the high-temperature regime.}, keywords = {Bouteloua eriopoda, Eragrostis chloromelas, soil moisture tension, survival}, url = {/files/bibliography/116.pdf}, author = {C.H. Herbel and R. E. Sosebee} } @article {52445, title = {Morphology of the argillic horizon in desert soils of southern New Mexico}, journal = {Soil Science}, volume = {106}, number = {1}, year = {1967}, note = {//LOCAL//NONE//}, month = {1967}, pages = {6-15}, abstract = {Reddish brown horizons of silicate clay accumulation occur in various desert soils of a study area stride the Rio Grande Valley of southern New Mexico (fig. 1). These horizons of clay accumulation are considered to be argillic horizons, although clay skins on ped surfaces and on pore walls are usually absent. Presence of clay skins on soil features that formed in place, such as peds, indicates clay movement subsequent to parent material deposition. Thus, clay skins demonstrate illuviation and are an important marker of an argillic horizon (15). In this desert area, however, clay skins must be waived as a requirement for argillic horizons. Instead, the features characteristic of the argillic horizon are coatings of oriented clay on sand grains and pebbles, or bodies of oriented clay within peds, or both. Illustrative soils have been selected to demonstrate the range in morphology of the argillic horizon as influenced by texture, authigenic carbonate, and soil age. Reasons for the absence of clay skins are discussed.}, keywords = {article, articles, geomorphology, argillic horizon, journal, journals, soil, argillic horizon}, author = {L. H. Gile and R. Grossman} } @article {52462, title = {Morphological and genetic sequences of carbonate accumulation in desert soils}, journal = {Soil Science}, volume = {101}, number = {5}, year = {1966}, note = {//LOCAL//NONE//}, month = {1966}, pages = {347-360}, abstract = {Horizons with authigenic carbonate are common soils of arid regions and are in many of these soils the most prominent horizon. In a previous paper (4) the K horizon was proposed for those carbonate horizons so strongly carbonate-impregnated that their morphology is determined by the carbonate. The carbonate accumulations in K horizons occur in a variety of macroscopic forms, and range in consistence from soft to extremely hard, but they all have a diagnostic fabric (the K-fabric) in which fine-grained carbonate coats or engulfs skeletal pebbles, sand , and silt grains as an essentially continuous medium. Thus, the K horizon concept includes many prominently carbonate-impregnated horizons, termed variously as caliche, desert crust, calcrete, or croute calcaire, but excludes numerous partially carbonate-impregnated soil horizons and conveys little idea of its won subhorizon sequences or genesis. In this paper, sequences of carbonate horizon morphologies apparently due to progressive carbonate accumulation, and apparently forming the genetic routes to formation of K horizons, are described and discussed.}, keywords = {article, articles, carbonate, horizon morphology, geomorphology, carbonate accumulation, journal, journals, soil, carbonate accumulation, soil, K horizon}, author = {L. H. Gile and F. F. Peterson and R. Grossman} } @article {52467, title = {Mesquite [Prosopis juliflora (Sw.) DC.]}, year = {1966}, month = {1966}, pages = {26}, publisher = {U.S. Department of Agriculture and Department of the Interior, Chemical Control of Range Weeds, Interagency Report}, abstract = {Mesquite--On sandy soils in southern New. Mexico and western Texas, individual plant treatments with fenuron pellets and monuron powder have consistently given high plant skills. Fenuron-trichloroacetate (TCA), monuron-TCA, and tricblorobenzoic acid are less effective. Effective on sandy soils is an individual plant treatment of 1 gram of active ingredient of fenuron pellets or monuron powder for each foot of canopy diameter. The materials should be well scattered around the base of the plant. Since these materials are desensitized by light and high temperatures, it is important that the materials be applied just prior to or in the early part of an expected rainy season. This method is economical in controlling sparse stands (up to 75 plants per acre) of mesquite on sandy soils in southern New Mexico and western Texas.}, keywords = {description, government publication, mesquite, plant treatment, Prosopis juliflora}, url = {/files/bibliography/096.pdf}, author = {C.H. Herbel} } @article {52501, title = {Mesquite control with monuron, fenuron, and diuron}, year = {1963}, note = {//??//NONE//}, month = {1963}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, chapter, chapters, herbicide,diuron, herbicide,fenuron, herbicide,monuron, Prosopis,herbicide, report, reports}, isbn = {Bulletin 484}, author = {Norris, J. J. and Valentine, K. A. and J. B. Gerard} } @article {JRN54200, title = {Managing Grass-Shrub Cattle Ranges in the Southwest}, volume = {62}, year = {1959}, pages = {1-40}, publisher = {US Forest Service}, edition = {Agriculture Handbook}, abstract = {

Grass-shrub rangelands occupy extensive acreages in southeastern Arizona and southwestern New Mexico between elevations of 3,000 and 5,000 feet. At lower elevations, the grass-shrub type merges with deserts dominated by creosotebush2.\  At higher elevations, the type forms a transition with chaparral, pinyon-juniper, or oak-woodland types (fig.1). Perennial grasses are the mainstay of the forage supply but browse species and annual grasses are sometimes important.

Sustained high production of perennial grass forage depends upon stocking the proper number of animals, grazing at appropriate times, and providing for optimum distribution of livestock. The usual practice is to graze the ranges yearlong. Annual or periodic adjustments in number of grazing animals are necessary because of wide variations in forage production. Seasonal adjustments are also helpful. Grazing can often be planned to make summer use of abundant annuals at lower elevations, spring use of ranges where browse is abundant, and winter use of ranges where black grama is an important component.

}, keywords = {cattle, grass-shrub, managing, Santa Rita}, issn = {62}, url = {/files/bibliography/1959-1.pdf}, author = {Reynolds, Hudson G.} } @article {52532, title = {Mountain or mesa range; a comparison of costs and returns determines relative value of each}, journal = {The American Hereford Journal}, volume = {44}, number = {9}, year = {1953}, month = {August 15, 1953}, pages = {104-105}, abstract = {Anyone who has had ranching experience knows that it costs more to run cattle and produce beef on rough, rugged mountain range than on level, easily accessible mesa range. Yet, little if any detailed information is available on comparative costs and returns from ranching in the two kinds of cattle range in the semiarid Southwest. Information is provided here on the various items of operating costs and the factors influencing them. It should point the way to more efficient herd and range management and aid in appraising the sale, rental or lease value of the two kinds of ranges. Comparative records of costs and returns from both mesa and mountain rangelands have been obtained for a 7-year period, from 1940 through 1946, on the Jornada Experimental Range, a branch of the Southwestern Forest and Range Experiment Station, 23 miles north of Las Cruces, New Mexico. Even though, because of changing economic conditions, the data applydirectly only to the period of record, they provide a good economic comparison between the two types of range when grazed by cattle of the same herd and managed by a single operator.}, keywords = {comparison of costs and returns, mesa range, rugged mountain range}, url = {/files/bibliography/077.pdf}, author = {F.N. Ares} } @article {52558, title = {A method of estimating weaning weights of range calves at a constant age}, journal = {Journal of Animal Science}, volume = {4}, year = {1945}, note = {//??//NONE//(New Mexico Agr. Exp. Station Journal Article 34)//}, month = {1945}, pages = {285-290}, keywords = {article, articles, cattle, productivity, journal, journals}, author = {Koger, M. and Knox, J. H.} } @article {52560, title = {The monthly protein and phosphorus contents of two important range grasses of Southern New Mexico}, journal = {Journal of Animal Science}, volume = {4}, year = {1945}, note = {//??//NONE//(New Mexico Agr. Experiment Station Journal Article 34)//}, month = {1945}, pages = {298-305}, keywords = {article, articles, biochemistry,phosphorus, biochemistry,protein, grass,biochemistry, grass,phosphorus, grass,protein, journal, journals, phosphorus,grass}, author = {Watkins, W. E. and Knox, J. H.} } @article {52563, title = {Measurement of grazing use by the line-interception method}, journal = {Journal of Forestry}, volume = {42}, year = {1944}, month = {1944}, pages = {192-194}, abstract = {Field experience in the Southwest has demonstrated the suitability of the line interception method for combining the measurement of utilization with plant density and composition estimates. It includes the advantages of actual measurement and random sampling. Moreover, the data obtained lend themselves readily to statistical analysis. The method operates equally well in sampling both large and small pastures.}, keywords = {large and small pastures, line interception method, measurement of grazing use}, url = {/files/bibliography/066.pdf}, author = {Canfield, R.H.} } @article {52587, title = {Maintaining the balance between summer and winter forage on black grama ranges under yearlong grazing use}, number = {Research Note 81}, year = {1939}, month = {1939}, pages = {4 }, institution = {USDA, Forest Service, Southwest Forest and Range Experimental Range Station}, abstract = {

Black grama type important in the Southwest. Black grama (Bouteloua eriopoda) is one of the most highly prized forage grasses in Arizona, New Mexico, and west Texas. Although it is often the dominant grass on the lower plains, it is rarely found in pure stands over very large areas. Other grasses, mainly sand dropseeds (Sporobnlus spp.), the three-awn grasses (Aristida spp.), and other species of grama, are almost invariably mixed with it. Usually, on undeteriorated black-grama-type range, this mixture is comprised of about 80 to 85 percent black grama and 15 to 0 percent other grasses. Because of differences in their seasons of usability, the relative proportion of black grama and the associated grasses is an important factor to be considered in range management.

}, keywords = {black grama, Bouteloua eriopoda, forage grass, highly prized, range management, research notes}, url = {/files/bibliography/049.pdf}, author = {Canfield, R.H.} } @article {52592, title = {Monthly variation in carotene content of two important range grasses, Sporobolus flexuosus and Bouteloua eriopoda}, journal = {Journal of Agricultural Research}, volume = {58}, year = {1939}, note = {//NMSU//NONE//}, month = {1939}, pages = {695-99}, abstract = {

The monthly carotene content of two important southern New Mexico range grasses, black grama and mesa dropseed, has been presented. Both grasses are moderately high in carotene during the growing season. The mesa dropseed loses all of its carotene soon after the fall freezes end the growing season. The black grama grass, whose upright stems remain green for a distance of from 4 to 6 inches of their base throughout the winter, contain an amount of carotene that seems to be ample to satisfy the vitamin A requirements of range cattle.

}, keywords = {article, articles, biochemistry,Bouteloua, biochemistry,Sporobolus, Bouteloua,carotene, grass,nutrients, grass,Sporobolus, journal, journals, Sporobolus,carotene}, url = {/files/bibliography/175.pdf}, author = {Watkins, W. E.} } @article {52597, title = {Mineral supplements for cattle on phosphorus-deficient range}, year = {1937}, note = {//??//NONE//}, month = {1937}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, cattle,phosphorus, cattle,supplements, chapter, chapters, nutrient,cattle supplements, phosphorus,cattle, report, reports}, isbn = {Bulletin 249}, author = {Knox, J. H. and Neale, P. E.} } @article {52607, title = {Management of black grama ranges}, journal = {American Hereford Journal}, volume = {26}, year = {1935}, month = {1935}, pages = {74-76}, keywords = {black grama, management}, author = {R.S. Campbell} } @article {52621, title = {Methods of studying shrubby plants in relation to grazing}, journal = {Ecology}, volume = {11}, year = {1930}, month = {1930}, pages = {764-769}, abstract = {

The development of methods for studying shrubby plants in relation to grazing are of importance principally because of the value of shrubs as a vegetative cover for watersheds on western range lands and because many species rank high in forage value for livestock.

}, keywords = {clay soils, grazing, methods, overgrazing, plant succession, shrubby plants}, url = {/files/bibliography/019.pdf}, author = {Nelson, E. W.} }