@article {JRN55343, title = {Long-term permanent quadrat sampling project at the Jornada Experimental Range, New Mexico}, year = {2022}, publisher = {Bulletin of the Ecological Society of America}, abstract = {The permanent chart quadrat project at the Jornada Experimental Range was established in 1915. Chart quadrat sampling is done using a pantograph, wherein technicians use a stylus attached to an arm to trace the perimeter of plants within the quadrat, and a pencil at the other end of the arm maps the information onto the data sheet. The Jornada quadrat monitoring effort collected yearly data from 1915 to 1979 and resumed at 5- year intervals beginning in 1995. Quadrat data have been used to understand patterns and mechanisms of long- term vegetation change, plant demography, species interactions, and community transitions.}, keywords = {Jornada Experimental Range, Long-term permanent quadrat sampling, New Mexico, project}, doi = {10.1002/bes2.1940 }, url = {files/bibliography/22-001.pdf}, author = {Erica M. Christensen and Connie J. Maxwell and A. L. Slaughter} } @article {JRN55428, title = {Landscape dynamics of a vector-borne disease in the western US: How vector{\textendash}habitat relationships inform disease hotspots}, year = {2022}, abstract = {Vesicular stomatitis (VS) is a vector-borne viral disease that causes lesions in livestock, premises, county and state quarantines, and important economic losses. We investigated vector{\textendash}habitat characteristics for vectors associated with VS in regions of recurrent disease within the western United States (US) that consistently lead to the environment where vector, host, and pathogen populations intersect to enable pathogen transmission. We analyzed the habitats of previously identified insect vectors, including black flies (BFs) (Simulium vittatum complex), biting midges (BMs) (Culicoides variipennis complex, which includes Culicoides sonorensis), and sand flies (SFs) (Lutzomyia shannoni) in six regions of interest (ROIs) containing hotspots of VS ranging from Texas (TX) to Wyoming. This analysis broadened the understanding of (1) how regions of reoccurring VS differ from the broader western US, (2) how geographically separated regions and hotspots are similar across time, and (3) how vector{\textendash}environment habitat a priori knowledge relates to observed hotspots. Analysis of watershed factors (livestock densities, land-cover proportions, stream and lake densities, and irrigation methods) indicated a complex system separating areas with high, recurring VS from the broader western US. Although no single characteristic separated the six ROIs from other areas, we found two distinct emerging groups (northern ROI and TX). Hotspots, estimated from monthly VS concentrations, evolved northward throughout the year and most hotspots were closer to flowing water and agricultural land than the broader ROI. All ROIs contained environmental conditions suitable for multiple vectors at some point in the year, but BFs had the highest suitability scores, whereas BM scores were lower and varied annually with higher suitability in summer. SFs had the lowest suitability score in all ROIs, consistent with their low likelihood of being vectors. BM habitat patches were often orders of magnitude smaller than BF patches, and hotspot patches reinforce the likelihood that BF may be the most critical vector in northern ROI, whereas both BM and BF have similar likelihood in southern ROI. Given limited existing vector data, this analysis provides an alternate pathway for using habitat information to associate likely vectors responsible for transmission. Results could support early warning and mitigation efforts to reduce the incidence of VS.}, keywords = {livestock, nidus, patch analysis, Vector-borne disease, vesicular stomatitis virus}, doi = {10.1002/ecs2.4267}, url = {files/bibliography/22-025.pdf}, author = {Emile H. Elias and Heather M. Savoy and Dustin A Swanson and Lee W. Cohnstaedt and Debra P. C. Peters and J. D. Derner and Angela Pelzel-McCluskey and Barbara Drolet and Luis Rodriguez} } @article {JRN55408, title = {Long term agroecosystem research experimental watershed network}, journal = {Hydrological Processes}, volume = {36}, year = {2022}, month = {3/7/2022}, pages = {e14534}, abstract = {The USDA-Agricultural Research Service (ARS) has a multi-decadal to century long history of experimental watersheds, ranges and research farms throughout the USA. Many of these ARS research facilities, as well as three led by private foundations or land grant universities, are now part of the USDA Long-Term Agro-ecosystem Research (LTAR) network that currently has 18 locations. These 18 locations encompass a diversity of agricultural systems as well as provide a research platform for regional to national scale assessments and modeling scenarios of ecosystem goods and services for society. LTAR will expand the mission of the ARS Experimental Watersheds network to include intensification of agricultural production, without ecosystem degradation while working to enhance rural prosperity. A central challenge that LTAR will address is: How can we sustain or enhance agricultural productivity, profitability, and ecosystem services to feed 9 billion people by 2050? To accomplish the central challenge, LTAR locations will leverage existing historical data with new network-level data collection and initiatives such as wind erosion, phenology, water/carbon/nutrient/energy fluxes, complete water balances, greenhouse gas fluxes and remote sensing/modeling efforts to determine the sustainability of US agriculture across regional to continental scales. This presentation will provide a brief overview of the LTAR network as well as links to access site location data.}, keywords = {experimental watersheds, history, range, research farms, USA}, doi = {10.1002/hyp.14534}, url = {files/bibliography/22-020.pdf}, author = {David C. Goodrich and David D. Bosch and Ray Bryant and Mike H. Cosh and Dinku Endale and Tamie Veith and Peter J. A. Kleinman and Eddy Langendoen and Gregory McCarty and Frederick B. Pierson and Harry Schomberg and Douglas Smith and Patrick Starks and Timothy Strickland and T. Tsegaye and Tala Awada and Hilary Swain and J. D. Derner and Brandon T Bestelmeyer and Marty Schmer and J. M. Baker and B. R. Carlson and David Huggins and D W Archer and G. Armendariz} } @article {JRN55430, title = {Long-term growing season aridity and grazing seasonality effects on perennial grass biomass in a Chihuahuan Desert rangeland}, journal = {Journal of Arid Environments}, volume = {209}, year = {2022}, month = {19 November 2022}, chapter = {104902}, abstract = {Growing season aridity and livestock grazing seasonality can influence primary productivity of perennial grasses in dryland systems. For this study, we used a long-term dataset (1967{\textendash}2004) to investigate the independent and joint effects of growing season aridity and season of grazing (yearlong continuous, fall, winter/spring, or summer season grazing) on the mean annual primary productivity of the perennial grasses Bouteloua eriopoda (black grama), Aristida spp. (threeawn), and Sporobolus spp. (dropseed) in a southwestern United States Chihuahuan Desert rangeland system. Over the 37-year study period, total perennial grass biomass decreased as aridity increased, but the extent of this relationship depended upon season of grazing and specific grass taxon. Aridity-related decreases in total perennial grass biomass were most severe in the summer grazing treatment. Our findings indicate that over time, summer and fall grazing can potentially exacerbate the negative effects of increasing aridity on perennial grass biomass. As arid and semi-arid rangelands globally face increasing aridity associated with a changing climate, land managers can modulate the season of grazing, dependent on dominant taxa present, to minimize these effects. Our study and those from other arid land locations indicate continuous grazing at light to conservative intensities can better sustain key perennial grasses than strategies involving concentrated seasons of grazing. However, growing season aridity levels must also be taken into consideration.}, keywords = {Aridity, black grama, drylands, perennial grass, rotational grazing, Sporobolus}, doi = {10.1016/j.jaridenv.2022.104902}, url = {files/bibliography/22-027.pdf}, author = {Sophia N. Lasch{\`e} and Ryan W.R. Schroeder and Matthew M. McIntosh and Jacob E. Lucero and S. Spiegal and M. Funk and Reldon F. Beck and Jerry L. Holechek and Akasha M. Faist} } @article {JRN55429, title = {LandPKS Toolbox: Open-source mobile app tools for sustainable land management}, journal = {Journal of Soil and Water Conservation}, volume = {77}, year = {2022}, month = {11/14/2022}, pages = {91A-97A}, abstract = {Land use planning and implementation of productive, sustainable land management practices requires careful matching of land use with its sustainable land potential at the field and even sub-field scale (FAO 2022). Sustainable land potential is defined as the potential of the land to generate ecosystem services for current and future generations (United Nations Environment Programme and International Resource Panel 2016). Appropriate matching of land use with land potential requires accurate, site-specific knowledge of land, including information on its long-term potential (based on inherent properties like texture, minerology, and slope), current condition (e.g., fertility, soil organic matter content, vegetation cover), and expected response to disturbances (e.g., management, climate). When land managers lack access to such information and knowledge, they are less likely to make informed management decisions that ensure long-term sustainability. To bridge this information gap, the Land Potential Knowledge System mobile application (LandPKS) was created with the goal of providing location-specific information on land potential that farmers and other land managers can use to make informed management decisions (Herrick et al. 2013, 2016). However, awareness of the availability of this free, open-source app with access to both US and global soil information remains low. The objective of this paper is to describe the app, with a focus on the recently released {\textquotedblleft}Toolbox{\textquotedblright} feature.}, keywords = {LandPKS Toolbox, mobile app, Open-source, planning, productive, soil texture, sustainable land management, tools}, doi = {10.2489/jswc.2022.0927A}, url = {files/bibliography/22-026.pdf}, author = {Jonathan Maynard and Sabina Maniak and Laura Hamrick and George Peacock and Sarah McCord and Jeffrey E. Herrick} } @proceedings {JRN55417, title = {Long-term effects of stocking rate, year, and weather on honey mesquite canopy cover and density}, year = {2022}, abstract = {Abiotic (precipitation, temperature) and biotic (grazing) factors are thought to be important drivers of undesirable woody shrub encroachment in arid rangelands. Woody encroachment has pervaded global rangelands over the past century, but the relative impacts of either grazing or climate are still not fully understood. We sought to evaluate the long-term (25 years; 1995-2019) effects of stocking rate (light: 25-30\% and conservative: 35-40\%; key forage species use rate), year, and the interaction of stocking rate by year to explore the impacts of grazing and annual weather fluctuations on percent cover and density of honey mesquite (Prosopis glandulosa), a native but invasive shrub, at the Chihuahuan Desert Rangeland Research Center (CDRRC) in southern New Mexico. Precipitation data were collected continuously at the CDRRC; temperature data were collected at the neighboring USDA-ARS Jornada Experimental Range. Drought occurred in 12 of 25 study years and mean ambient summer temperature increased from 15.1 {\textpm} 0.15 to 15.4 {\textpm} 0.27{\textdegree}C between the first and last 12 years of the study period. We found that stocking rate and the interaction of stocking rate by year had no effect on mesquite percent cover or density (\% cover: P = 0.70; density: P = 0.10), although year had a significant effect (\% cover: P < 0.01; density: P < 0.01). Mesquite canopy cover increased by 3\% from 3.8 to 7.1\% cover and mesquite density increased by 175\% (P < 0.01) from 284 {\textpm} 53 plants*ha to 782.08 {\textpm} 35 plants*ha between the last vs first three years of the study. Our preliminary results support a growing body of literature that suggests the overriding effects of climate (increased temperatures and prolonged droughts) will continue to drive undesirable shrub encroachment on Chihuahuan Desert rangelands even when animal stocking rates are kept at historically sustainable levels.}, keywords = {and density, canopy cover, honey mesquite, Long-term effects, stocking rate, weather, year}, author = {Matthew M. McIntosh and Jerry L. Holechek and S. Spiegal and Andr{\'e}s F. Cibils and Richard E. Estell and Caitriana Steele and Jeon, S. and Brandon T Bestelmeyer} } @article {JRN55375, title = {Lessons given and learned from rangeland monitoring courses}, journal = {Rangelands}, volume = {44}, year = {2022}, month = {3/1/2022}, pages = {29-38}, abstract = {On the Ground {\textbullet} Monitoring courses, offered at universities and through professional training, are critical to successfully collecting and applying rangeland monitoring data. {\textbullet} Instructors can meet course objectives by carefully considering course content, the target audience, delivery approaches, evaluation mechanisms, and training for new instructors. {\textbullet} Shared principles and practices taught in monitoring courses facilitate the rangeland management community in achieving desired outcomes through adaptive management.}, keywords = {academia, active learning, hybrid courses, learning style, teaching style, training}, doi = {https://doi.org/10.1016/j.rala.2021.08.003}, url = {files/bibliography/22-007.pdf}, author = {Beth Newingham and Emily Kachergis and Amy Ganguli and Baili Foster and Lauren Price and Sarah McCord} } @article {JRN55310, title = {The Long-Term Agroecosystem Research network standard GIS data layers}, year = {2021}, month = {03/01/2021}, abstract = {The USDA Long-Term Agroecosystem Research was established to develop national strategies for sustainable intensification of agricultural production. As part of the Agricultural Research Service, the LTAR Network incorporates numerous geographies consisting of experimental areas and locations where data are being gathered. Starting in early 2019, two working groups of the LTAR Network (Remote Sensing and GIS, and Data Management) set a major goal to jointly develop a geodatabase of LTAR Standard GIS Data Layers. The purpose of the geodatabase was to enhance the Network{\textquoteright}s ability to utilize coordinated, harmonized datasets and reduce redundancy and potential errors associated with multiple copies of similar datasets. Project organizers met at least twice with each of the 18 LTAR sites from September 2019 through December 2020, compiling and editing a set of detailed geospatial data layers comprising a geodatabase, describing essential data collection areas within the LTAR Network. The contents of the LTAR Standard GIS Data Layers geodatabase includes geospatial data that represent locations and areas associated with the LTAR Network as of late 2020. The geodatabase includes spatial data describing LTAR site locations, addresses, experimental plots, fields and watersheds, eddy flux towers, and phenocams. There are six data layers in the geodatabase available to the public. This geodatabase was created in 2019-2020 by the LTAR network as a national collaborative effort among working groups and LTAR sites. The process to create the geodatabase began with initial requests to LTAR site leads and data managers for geospatial data, followed by meetings with each LTAR site to review the initial draft. Edits were documented, and the final draft was again reviewed and certified by LTAR site leads or their delegates. Revisions to this geodatabase will occur biennially, with the next revision scheduled to be published in 2023. }, doi = {10.15482/USDA.ADC/1 521161}, author = {G. Armendariz and A. W. Coffin and D W Archer and Dan Arthur and A. R. Bean and Dawn M. Browning and B. R. Carlson and Patrick E. Clark and Colton K Flynn and Sarah Goslee and Sclater, V. and Sudduth, K.A. and N. E. Kaplan and Stinner, J.H. and K.W. King and S. Spiegal and Hsieh, H. and G. E. Moglen and Yasarer, L.M. and Kettler, T.A. and Schmer, M.R. and Teet, S.B. and Paul F. Starrs and Hall, V.O. and Wagner, S.W. and Jane M. F. Johnson and Chandra D. Holifield Collins and Kautz, M.A.} } @article {JRN55331, title = {Long-term network research for the next agricultural revolution}, journal = {Frontiers in Ecology and the Environment}, volume = {19}, year = {2021}, month = {10/01/2021}, pages = {432-434}, abstract = {Interwoven into society as a source of food, nutrition, livelihoods, and monetary resources, agriculture shapes and depends on the environment. Threats to modern agricultural landscapes include climate change, soil degradation, eutrophication, and loss of wildlife habitat. Farmers and ranchers are working to mitigate these threats within financial and social limitations, but new technologies and quantitative targets are essential to guide the transformation of modern agriculture (Hunter et al. 2017). Agriculture also faces increasing demands from growing populations, rising wealth, and concomitant changes in food preferences that impact the entire food system, from food production to food and waste distribution (Ramankutty et al. 2018). While the previous agricultural revolution focused primarily on increasing crop yields around the globe, the next agricultural revolution must maintain and/or increase production while conserving natural resources for future generations and improving human well-being (USDA 2020). There is a continued need for increasing yields in some areas of the world as an important strategy for addressing land pressures and reducing environmental costs (Jayne and Sanchez 2021). In the next agricultural revolution, novel sustainability strategies must become realized (Meynard et al. 2017) through adoption of individual practices or through transformation of entire food production systems, all in the context of rapid global change. The varied technologies required to achieve this goal are captured in the concept of {\textquotedblleft}sustainable intensification{\textquotedblright} (Pretty 2018) and are central to the science goals of the US Department of Agriculture (USDA 2020).}, keywords = {agricultural revolution, agriculture, agriculture shapes, environment., food, livelihoods, Long-term network research, monetary resources, nutrition}, doi = {10.1002/fee.2403}, url = {files/bibliography/21-043.pdf}, author = {Elizabeth H. Boughton and Brandon T Bestelmeyer and Peter J. A. Kleinman and Glenn E Moglen and S. Spiegal and T. Tsegaye} } @proceedings {JRN55426, title = {Leveraging standardized monitoring data to support grazing land soil erosion assessments}, year = {2021}, month = {7/31/2021}, abstract = {The LTAR Rangeland Soil Erosion Working Group formed with the objective of coordinating the use of standardized national inventory and monitoring datasets to assess wind and water erosion impacts across US grazing lands. The Rangeland Soil Erosion Working Group is comprised of LTAR scientists, members of USDA-NRCS CEAP Grazing Lands project, as well as collaborators at the Bureau of Land Management and US Geological Survey. The first task of the group was to transform standardized monitoring data, housed in the Landscape Data Commons, into appropriate input formats to parameterize water (RHEM) and wind (AERO) erosion models. To accomplish this task, we coordinated with each modelling team to build accurate data models for each erosion model. This included: 1) identifying each input variable or indicator needed, 2) describing the correct calculation of each variable based on available monitoring data, 3) refining a common species list and functional group list for all species occurring on US grazing lands, and 4) applying the data model to the monitoring data to produce model input and parameterization files. As of July 2021, the data model development process is complete. The data model has been applied to over 60,000 grazing land inventory and monitoring locations nationally, enabling RHEM and AERO applications to those locations. The development of new analyses will support project stakeholders (NRCS CEAP and BLM) and provide erosion indicators across US grazing lands that can be used in the LTAR sustainable intensification indicators framework. }, keywords = {assessments, data, grazing land, Leveraging, monitoring, soil erosion, standardized, support}, author = {Sarah McCord and Nicholas Webb and Kristopher Bonefont and Ericha Courtright and Danielle Duni and Brandon Edwards and David C. Goodrich and Phil Heilman and Mariano Hernandez and Loretta Metz and Mark A. Nearing and Beth Newingham and Nichols, Mary H. and Frederick B. Pierson and John Tatarko and David P. Toledo and Scott Van Pelt and Justin Van Zee and Jason Williams} } @conference {JRN55303, title = {Long-term declining trends in Chihuahuan Desert forage production in relation to stocking rates and climate}, booktitle = {Society for Range Management Meeting Abstracts}, year = {2021}, month = {02/15/2021}, abstract = {We analyzed a 25-yr time series (1995 {\textendash} 2019) of stocking rate (SR), ambient temperature, precipitation, and perennial grass production (PGP) at a 4000-ha site in the Chihuahuan Desert. Using the Proc Glimmix procedure in SAS 9.4, we analyzed effects of two SRs (light: 25-30\% vs conservative: 31-40\% forage use rate), year, and SR {\texttimes} year to evaluate time trends. Stocking rates had no effect on PGP (P~= 0.25), but year did (P~< 0.01). Stocking rate {\texttimes} year did not affect PGP (P~= 0.94). We found a 75\% reduction in in kg * ha-1~PGP when the first (115.4 {\textpm} 18.7 kg DM perennial grass) vs last three (28.27 {\textpm} 18.67 kg DM perennial grass) study years periods were compared (P~< 0.01). Annual average ambient temperature during the 25-y study increased by more than 1{\textdegree}C (beginning: 15.22 {\textpm} 0.2 vs end: 16.7 {\textpm} 0.2{\textdegree}C). Mean maximum June temperature (P~< 0.01;~r~= - 0.39) was negatively associated with PGP. Conversely, PGP was positively associated with total annual precipitation (P~< 0.01; r = 0.28). The interaction of June mean maximum temperature and annual precipitation negatively affected PGP (P~< 0.01). These preliminary results suggest that climate may have an overriding effect on Chihuahuan Desert forage production even when appropriate stocking rates are applied. Sustainability of beef production systems on southwest rangeland will increasingly be hampered by forage yields less than 100 lb*ac-1; the point at which point livestock grazing becomes financially unsound.}, author = {Matthew M. McIntosh and Jerry L. Holechek and Andr{\'e}s F. Cibils and Richard E. Estell and S. Spiegal} } @conference {JRN55295, title = {Landscape use of Angus Crossbred vs. Raramuri Criollo cattle on desert rangeland}, booktitle = {Society for Range Management Meeting Abstracts}, year = {2021}, month = {2/15/2021}, abstract = {We conducted a replicated study (in both space and time) to validate previous findings reporting differences in grazing patterns of Raramuri Criollo (RC, heritage breed) vs. Angus Hereford crossbred (AH, commercial breed) cows grazing Chihuahuan Desert rangeland. We monitored cows of both breeds that grazed desert pastures separately during summer and winter in three consecutive years. GPS positions were acquired from 5 to 11 randomly selected cows of each breed and were classified based on movement velocity. Presumed grazing locations were used to calculate Ivlev{\textquoteright}s electivity index to determine preference (E>0) or avoidance (E<0) of pixels relative to thirteen pasture attributes including topography, vegetation, facilities, temperature, and moisture variables. Statistical mixed models were used to determine the effects of breed and season on selection of pixels. Separate analyses were conducted for each pasture attribute. Both breeds avoided areas far from water, but RC cows showed higher preference for pixels close to the drinker during the dormant season. RC cows appeared to exhibit a keener ability to select pixels with differing surface temperature, and greenness compared to AH counterparts. RC cows showed greater preference for pixels with high shrub density than AH counterparts in summer. During the dormant season, both breeds preferred sites with high shrub density. AH cows exhibited a strong preference for black grama pixels and higher avoidance of pixels with high density of other grasses. RC cows, did not select pixels with high black grama cover. Average electivity values for each pixel (grazing likelihood) revealed remarkable season differences between breeds. In summer, both breeds appeared to prefer similar portions of the pasture, whereas in winter, pixel preference (and hence spatial distribution) of breeds diverged significantly. Our study confirmed previously reported differences in landscape use patterns of RC vs. AH beef cattle.}, 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} } @article {JRN55388, title = {Land use change and collaborative manureshed management in New Mexico}, journal = {Journal of Environmental Quality}, year = {2021}, month = {8/11/2021}, pages = {1-12}, abstract = {Agricultural communities of New Mexico regularly redistribute manure nutrients from dairies to nearby croplands to fulfill agronomic nutrient needs and protect water quality. Yet competition for water resources can result in land use change that affects these cooperative manure transfers. Focusing on three clusters of New Mexico dairy farms and their surrounding lands (three manuresheds), we calculated the magnitude of land use changes in 2008{\textendash}2019 and the balance between manure nutrient supply and crop demand in 2019 to assess how past change may predict future prospects for sustainable management. The overall magnitude of change was small, with each manureshed experiencing a different complement: an exchange of cropland and rangeland in the Roosevelt manureshed (7,975 ha rangeland to cropland; 7,624 ha cropland to rangeland), a 464-ha gain in cropland but a 1,187-ha loss of {\textquotedblleft}spreadable{\textquotedblright} land (cropland, rangeland, fallow) to developed land in the Do{\~n}a Ana manureshed, and relatively minor changes in the Chaves manureshed. Nutrient supply and demand were mainly in balance, but a surplus of manure phosphorus (P) in the Chaves manureshed and a thin margin of P assimilation by croplands in the Roosevelt manureshed point to the need for preserving existing croplands and understanding of effects of dairy manure on shortgrass rangeland. Our assessment suggests that an ideal scenario would entail manure being generated in landscapes with portfolios of productive lands that can sustainably use the manure nutrients to minimize environmental quality concerns and agronomic tradeoffs. Coordinated, participatory, and interdisciplinary research and planning are needed.}, keywords = {CDL, Cropland Data Layer; CRP, USDA{\textquoteright}s Conservation Reserve Program.}, doi = {10.1002/jeq2.20280}, url = {files/bibliography/21-061.pdf}, author = {S. Spiegal and Jebediah C. Williamson and Colton K Flynn and Anthony R. Buda and C. A. Rotz and Peter J. A. Kleinman} } @article {JRN55321, title = {Long-term research catchments to investigate shrub encroachment in the Sonoran and Chihuahuan deserts: Santa Rita and Jornada experimental ranges}, journal = {Hydrological Processes}, volume = {35}, year = {2021}, month = {January 2021}, pages = { e14031}, abstract = {Woody plant encroachment is a global phenomenon whereby shrubs or trees replace grasses. The hydrological consequences of this ecological shift are of broad interest in ecohydrology, yet little is known of how plant and intercanopy patch dynamics, distributions, and connectivity influence catchment-scale responses. To address this gap, we established research catchments in the Sonoran and Chihuahuan Deserts (near Green Valley, Arizona and near Las Cruces, New Mexico, respectively) that represent shrub encroachment in contrasting arid climates. Our main goals in the coordinated observations were to: (1) independently measure the components of the catchment water balance, (2) deploy sensors to quantify the spatial patterns of ecohydrological processes, (3) use novel methods for characterizing catchment properties, and (4) assess shrub encroachment impacts on ecohydrological processes through modeling studies. Datasets on meteorological variables; energy, radiation, and CO2 fluxes; evapotranspiration; soil moisture and temperature; and runoff at various scales now extend to nearly 10 years of observations at each site, including both wet and dry periods. Here, we provide a brief overview of data collection efforts and offer suggestions for how the coordinated datasets can be exploited for ecohydrological inferences and modeling studies. Given the representative nature of the catchments, the available databases can be used to generalize findings to other catchments in desert landscapes.}, keywords = {Chihuahuan deserts, Jornada experimental ranges, Long-term research catchments, Santa Rita, shrub encroachment, Sonoran}, doi = {10.1002/hyp.14031}, url = {files/bibliography/21-044.pdf}, author = {Enrique Vivoni and Eli R. Perez and Zachary T Keller and Eric Escoto and Ryan Templeton and Nolie P Templeton and C.A. Anderson and A. P. Schreiner-McGraw and Luis A. M{\'e}ndez-Barroso and Agustin Robles Morua and R.L. Scott and Steven R. Archer and Debra C. Peters} } @proceedings {JRN55186, title = {Land of Encroachment: A multi-stakeholder assessment of brush control efforts in New Mexico}, year = {2020}, month = {02/16/2020}, address = {Denver, CO}, abstract = {

The social impacts of ecological restoration are not well understood.\  Yet, social processes are inherently at work while defining and prioritizing desirable landscape change and acceptable levels of intervention. We use a cultural ecosystem service (CES) framework to test the relevance of CES to grassland restoration by contrasting CES values between stakeholders engaged in restoration planning and management and those representing a wider suite of CES. Using semi-structured interviews (n=34), we engage partners in an ongoing restoration initiative (restoration partners) and others who derive cultural value from the landscape (other CES stakeholders) Interview results reveal that ecological change, such as enhanced wildlife habitat and vast, open spaces improve aesthetic value, recreation, and lifestyle CES. Second, management action such as longevity of interventions, restricted access to treatment areas, and federal policy associated with cattle forage hinder these CES as well. Lastly, social processes such as trust in management, attitudes towards stakeholder groups, and differences in perceptions of CES can hinder how people experience the environment. Inclusion of CES leads to holistic management strategies that cater to the entire socio-ecological system. We are currently exploring how stakeholders prioritize CES among other ecosystem services in our study area as well as the spatial distribution of values to see how management can best accommodate diverse perspectives across the landscape.

}, keywords = {assessment, brush control efforts, Land of Encroachment, multi-stakeholder, New Mexico}, author = {Maude Dinan and B. Cuttis} } @article {JRN55199, title = {Long-term ecological research and evolving frameworks of disturbance ecology}, journal = {BioScience}, volume = {70}, year = {2020}, month = {02/2020}, pages = {141-156}, chapter = {141}, abstract = {Detecting and understanding disturbance is a challenge in ecology that has grown more critical with global environmental change and the emergence of research on social{\textendash}ecological systems. We identify three areas of research need: developing a flexible framework that\  incorporates feedback loops between social and ecological systems, anticipating whether a disturbance will change vulnerability to other environmental drivers,\ and incorporating changes in system sensitivity to disturbance in the face of global changes in environmental drivers. In the present article, we\ review how discoveries from the US Long Term Ecological Research (LTER) Network have influenced theoretical paradigms in disturbance\ ecology, and we refine a framework for describing social{\textendash}ecological disturbance that addresses these three challenges. By operationalizing this\ framework for seven LTER sites spanning distinct biomes, we show how disturbance can maintain or alter ecosystem state, drive spatial patterns\ at landscape scales, influence social{\textendash}ecological interactions, and cause divergent outcomes depending on other environmental changes. }, keywords = {disturbance, ecological research networks, ecological theory, LTER, social{\textendash}ecological studies}, doi = {10.1093/biosci/biz162}, url = {files/bibliography/20-009.pdf}, author = {Gaiser, Evelyn E. and Bell, David M. and Max Castoroni and Daniel L. Childers and Peter M. Groffman and Rhett G. Jackson and Kominoski, John S. and Debra C. Peters and Steward T.A. Pickett and Ripplinger, Julie and Zinnert, Julie C.} } @proceedings {JRN55187, title = {LandPKS App for Planning and Monitoring Outcome-Based Grazing: New Features}, year = {2020}, month = {02/16/2020}, address = {Denver, CO}, abstract = {

Outcome-based grazing requires (1) defining management objectives that are realistic, (2) developing and implementing a management system , and (3) monitoring results. The Land-Potential Knowledge System (LandPKS) can be used to easily and cost- effectively address the first and third requirements. The latest version includes a soil- and ecological-site identification function. This function can be used to define realistic management objectives based on both the long-term (ecological site), and current (ecological state) potential. Soil identification is based on location and improved with user inputs of soil texture (using a simple key) and color (using the phone{\textquoteright}s camera and a post-it note for calibration). A direct link provides full access to the ecological site description in EDIT. The vegetation monitoring tool is rapid (20 minutes/plot), requires only a yardstick and a pin flag, and generates the same indicators as those used by BLM in its AIM program (though at a lower level of precision). It will also include a new feature providing access to habitat information for selected species in some regions. Comparing this information with current data and the ecological site description can help decide whether it{\textquoteright}s realistic to manage for desired wildlife species. The new Land Management module supports agronomic record keeping (including precipitation, tillage, fertilizer, weed control, etc.) which can also be used for planning and tracking restoration and remediation treatments . Finally, the new version includes a data privacy option. The LandPKS app is available on both iPhone and Android.

}, keywords = {LandPKS App, Outcome-Based Grazing, Planning and Monitoring}, author = {Jeffrey E. Herrick and S. W. Salley and J. Neff and Rachel Murph and Mize, M. and Jonathan Maynard and Brandon T Bestelmeyer} } @proceedings {JRN55185, title = {Landpks Soilid: A Smartphone-Based Soil Identification Tool for Rangeland Management}, year = {2020}, month = {2/16/2020}, address = {Denver, CO}, abstract = {

Accurately identifying soil class at a specific point-location or position within a landscape is critical for implementing sustainable soil management. Soil classes (e.g., soil components) are information carriers that allow land managers to infer a general range of soil behavior in response to management actions and disturbance effects. Recent advances in information technologies, in particular the global ubiquity of smart phones, has made it possible to create m.obile decision support tools that can inform rangeland management decisions. The Land Potential Knowledge System (LandPKS) is one such example, providing a complete mobile computing platform for assessing land potential and informing management activities. Here we present the development of a global soil identification modeling framework (SoillD) implemented within the LandPKS mobile app. SoillD leverages smartphone-based data acquisition and information delivery, with cloud-based computing to determine the most probable soil class at a user specified point. SoillD makes it possible for non-soil scientists to describe and identify soils in the field using limited, simple soil observations. Additionally, SoillD provides information on Ecological Sites based on the most probable soil class matched to the user{\textquoteright}s soil. Our presentation will describe the details of SoillD and its implementation in the LandPKS mobile app, and provide examples of its utility for rangeland management.

}, keywords = {rangeland management, Smartphone-Based Soil identification Tool}, author = {Jonathan Maynard and Jeffrey E. Herrick and S. W. Salley and Dylan, E. and D. Beaudette and A. O{\textquoteright}Green} } @article {JRN55173, title = {Land restoration for achieving the Sustainable Development Goals}, year = {2019}, abstract = {

The International Resource Panel{\textquoteright}s GRO report provides a unique framework for focusing both local and global investments in the SDGs on those activities that promote {\textquotedblleft}improved resource productivity and a relative decoupling of well-being [e.g. SDGs 1-7] from resource use{\textquotedblright}. The {\textquotedblleft}Sustainability Scenario{\textquotedblright} (IRP 2019), used by the GRO report to support its conclusion that decoupling is possible, is based in part on assumptions about global shifts in population growth and consumption patterns. But it also relies on the potential for significant increases in resourceuse efficiency (see https://www.resourcepanel.org/glossary for definitions of {\textquotedblleft}decoupling{\textquotedblright} and related terms).

}, url = {files/bibliography/19-027.pdf}, author = {Jeffrey E. Herrick and Tanya Abrahamse} } @article {JRN55158, title = {Long-term declining trends in Chihuahuan Desert forage production in relation to precipitation and ambient temperature}, journal = {Rangeland Ecology and Management}, volume = {72}, year = {2019}, month = {11/01/2019}, abstract = {

Rising temperatures and more frequent droughts are posing new challenges to range livestock producers in the southwestern United States and many other parts of the world. We analyzed a 49-year time series (1969-2017) of precipitation, ambient temperature, and perennial grass production (PGP) as well as 14 years (2001-2014) of MODIS-derived vegetation phenometrics at a site in the Chihuahuan Desert of New Mexico. PGP was positively associated with December through September precipitation (r = 0.74; P \< 0.05) but negatively associated
with spring and summer (Mar-Sep) maximum average ambient temperature (r = -0.54; P \< 0.05). PGP decreased by 38\% in the second (1994-2017) compared to first half (1969-1993) of our study (228 \± 36.75 vs. 141 \± 21.97 kg DM*ha-144 ; P \< 0.01). Precipitation was lower and more erratic in the second half of the time series decreasing by 21\% (264.88 \± 1.30 vs. 211.13 \± 16.67 mm; P = 0.01). Conversely, mean maximum and mean ambient temperatures were higher during the 1994-2017 period (max T: 24.48 \± 0.14 vs. 25.22 \± 0.13\°C; P \< 0.01; mean T:14.45 \± 0.13 vs. 15.04 \± 0.13\°C; P \< 0.01). MODIS-derived NDVI analysis showed that growing seasons began and ended later and became shorter (P \< 0.05) over the 14 years analyzed. During this period, increasing maximum summer (Jun-Sep) ambient temperatures were associated with decreasing growing season NDVI values (P \< 0.01). Over the 49-year study period, Chihuahuan Desert rangelands at our research site lost 38\% of grazing capacity. Nine drought years occurred in the second half of our study compared to two in the first half. Our research supports predictions by climate scientists that more frequent droughts and lower as well as more erratic precipitation will adversely impact grazing capacity of rangelands in the southwestern United States.

}, keywords = {climate change, forage, grazing capacity, NDVI, phenometrics}, doi = {10.1016/j.rama.2019.06.002}, url = {files/bibliography/19-025.pdf}, author = {Matthew M. McIntosh and Jerry L. Holechek and S. Spiegal and Andr{\'e}s F. Cibils and Richard E. Estell} } @conference {JRN54995, title = {Long-term Trends in Perennial Grass Production, Precipitation and Temperature in the Chihuahuan Desert}, 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 = {

Rising temperatures and more frequent droughts are posing new challenges to livestock producers in the Southwest. Our objective was to evaluate long-term perennial grass production (PGP) in the Chihuahuan Desert in relation to ambient temperature and precipitation. PGP was correlated with precipitation (mm) and ambient temperature (oC) over a 49-year period (1969 {\textendash} 2017). Increasing precipitation in December through September was associated with higher PGP (r = 0.74, n = 49) whereas rising maximum average temperatures in March through September were associated with a reduction in PGP (r = -0.54, n = 49). Two-sample t-tests comparing averages of each variable for the first and last 25 years of the study period (1969-1993 vs. 1994-2017) revealed that mean PGP decreased by 35\% (220.7 {\textpm} 12.5 vs. 143.92 {\textpm} 15.89 kg DM*ha-1; P \< 0.01), precipitation was more variable and decreased by 21\% (264.88 {\textpm} 1.30 vs. 211.13 {\textpm} 16.67 mm; P = 0.01), whereas mean maximum temperature (24.48 {\textpm} 0.14 vs. 25.22 {\textpm} 0.13{\textdegree}C; P \< 0.01) and mean temperature (14.45 {\textpm} 0.13 vs. 15.04 {\textpm} 0.13{\textdegree}C; P \< 0.01) increased by\  0.7oC and 0.6o C, respectively. Over this 49-year period, Chihuahuan Desert rangelands at our research site lost 35\% of grazing capacity (approximately 84 AUMs/1000 ha [7 AUYs/1000 ha]). Our research shows that increased temperatures and more frequent droughts are severely impacting forage and range livestock production in the southwest.

}, author = {Matthew M. McIntosh and Jerry L. Holechek and Andr{\'e}s F. Cibils and Richard E. Estell} } @conference {JRN54939, title = {Long-Term Research at the Jornada Basin (LTER VII)}, booktitle = {LTER All Scientists Meeting 2018}, year = {2018}, month = {10/2018}, address = {Pacific Grove, California}, abstract = {

Chihuahuan Desert landscapes exemplify the ecological conditions, vulnerability, and management challenges in arid and semi-arid regions around the world. The goal of the Jornada Basin Long Term Ecological Research program (JRN LTER) is to understand and quantify the key factors and processes controlling ecosystem dynamics in Chihuahuan Desert landscapes. In LTER-VII, we explore how spatial heterogeneity of dryland ecosystems evolves over time in response to disturbance triggers, positive feedbacks, and their interactions with the eco-geomorphic template.\  Our recent observations indicate the need to conceptually and computationally integrate data and knowledge into a Data Science Integrated System (DSIS).

}, author = {Debra C. Peters and Niall Hanan and Brandon T Bestelmeyer and Gregory S. Okin and O. E. Sala and Robert L. Schooley and Steven R. Archer and Stephanie Bestelmeyer and Colby Brungard and Ferran Garcia-Pichel and Jeffrey E. Herrick and Curtis H. Monger and Pietrasiak, Nicole and Craig Tweedie} } @proceedings {JRN54894, title = {Long-Term Agroecosystem Research Advancing Sustainable Intensification in Fields, Farms, and Regions Across the United States}, volume = {S12}, year = {2018}, month = {04/2018}, abstract = {

The Long-Term Agroecosystem Research network is building a road map for the sustainable intensification of U.S. agriculture by designing strategies that are locally appropriate and applicable to multiple scales of agricultural organization. The 18 sites in the LTAR network represent a diversity of land use types and environmental, economic, and social opportunities for sustainable intensification, yet commonalities among strategies for sustainable intensification are evident across the sites. Explicit attention to spatial pattern and process are interwoven into these common sustainable intensification strategies, and that conceptualization is allowing for useful qualitative and quantitative comparisons among rangelands, croplands, and pasturelands at field, farm, and regional scales. For instance, at the field scale, GPS technologies are allowing western rangeland scientists and eastern pastureland scientists to compare the use of pasture resources by cattle, and to exchange ideas about management approaches that can help improve grazing distribution for improved economic and environmental outcomes in both types of systems. In this talk we illustrate the connection between LTAR{\textquoteright}s research and various scales of agricultural organization and showcase one LTAR network initiative that integrates field, farm, region, and industry scales. With a focus on tightening resource cycles, this approach has the potential to advance sustainable intensification within and among the biogeographically diverse agroecosystems of the United States.

}, author = {S. Spiegal and Peter J. A. Kleinman} } @conference {JRN54793, title = {Landscape distribution of desert cattle: effects of diet and vegetation type}, booktitle = {Ecological Society of America Annual Meeting}, year = {2017}, month = {08/2017}, publisher = {Ecological Society of America Annual Meeting}, organization = {Ecological Society of America Annual Meeting}, address = {Portland, OR}, abstract = {

Livestock with heritage genetics may increase chances for simultaneously achieving conservation and agricultural production goals in the American Southwest. Past research shows that compared with conventional Angus x Hereford crossbreds (AH), heritage Raramuri Criollo (RC) typically distribute themselves more widely across Chihuahuan Desert landscapes. Accordingly, RC genetics may help overcome some of the problems associated with localized overgrazing in the region, but a better understanding of why RC range more widely is needed. Hypotheses under investigation pertain to differences in the breeds{\textquoteright} dietary preferences, heat tolerance, and mothering style. We explored the dietary preferences and heat tolerance of the two breeds during the growing season of 2015. Ten mature cows of each breed grazed two adjacent pastures (1190 ha, 1165 ha) for 28 days in July-August. They were switched between the pastures on the 14th day, and fecal samples were collected on the 14th and 28th days. GPS coordinates recorded at 10-min intervals were overlaid on habitat type maps, and Ivlev{\textquoteright}s electivity index (E) was calculated for each habitat type in each pasture. Fecal samples were examined for dietary composition with DNA metabarcoding, and we used ordination and ANOVA to compare the composition of the breeds{\textquoteright} samples. Selectivity of habitat types (E) and dietary composition differed between the two breeds in each pasture; however, habitat selection and dietary composition were surprisingly incongruent. In one pasture, heritage RC showed a stronger preference for shade-free areas of bare ground (ERC = 0.46; EAH = -1.00; P\<0.01), but the herbaceous species that grow in those areas constituted a lower proportion of their diets than they did in AH diets. In the other pasture, conventional AH showed a stronger preference for shadier mesquite dune areas (ERC = 0.05; EAH = 0.27; P = 0.01), but they consumed less mesquite than RC did. These results suggest that both breeds were moving more in response to thermal variation than to the availability of particular forage species, and that heat tolerance is an important factor driving differences in the spatial distribution of both breeds, at least in the summer months.

}, author = {S. Spiegal and Richard E. Estell and Andr{\'e}s F. Cibils and S. Nyamuryekung{\textquoteright}e and McIntosh, William C. and Amy L. Gonzalez} } @article {JRN54796, title = {Livestock Bonding for Improving Paddock Management: A Maui Case Study}, year = {2017}, month = {September 2017}, pages = {1-8}, abstract = {

Applying an understanding of animal behavior principles can meet several ranch-management objectives. Research has demonstrated that differences in foraging behavior among cattle, sheep, and goats can help control undesirable vegetation at relatively low cost. However, increasing the number of animal species on a ranch will usually increase management labor or infrastructure costs. Haleakala Ranch on Maui conducted livestock bonding trials to evaluate this behavior-based method as a low-cost way to improve grazing management and forage use. Bonding produced interspecific livestock groups of cattle, sheep, and goats that consistently remained together when moved. This cohesive interspecific livestock grouping, termed a flerd (Figure 1), was formed by socializing the small ruminants with cattle through close association. USDA Agricultural Research Service studies conducted at the Jornada Experimental Range in south-central New Mexico on bonding for reducing coyote predation of free-ranging sheep and goats formed the basis of the Haleakala Ranch trials. Livestock bonding shows potential in Hawai{\textquoteleft}i for improved control of livestock distribution across a paddock, increasing paddock use efficiency, and providing another layer of protection from feral dog or pig predation on sheep and goats.

}, url = {/files/bibliography/17-030.pdf}, author = {Matthew H. Stevenson and Greg Friel and D.M. Anderson} } @article {JRN54799, title = {Land degradation and climate change: building climate resilience in agriculture}, journal = {Frontiers in Ecology and the Environment}, volume = {15}, year = {2017}, month = {10/2017}, pages = {450-459}, chapter = {450}, abstract = {

Land degradation and climate change pose enormous risks to global food security. Land degradation increases the vulnerability of agroecological systems to climate change and reduces the effectiveness of adaptation options. Yet these interactions have largely been omitted from climate impact assessments and adaptation planning. We examine how land degradation can influence climate-change impacts and the adaptive capacity of crop and livestock producers across agroecological systems. We then present novel strategies for climate-resilient agriculture that support opportunities to integrate responses to these challenges. Forward-looking, climate-resilient agriculture requires: (1) incorporation of land degradation processes, and their linkages with adaptive capacity, into adaptation planning; (2) identification of key vulnerabilities to prioritize adaptation responses; (3) improved knowledge exchange across local to global scales to support strategies for developing the adaptive capacity of producers; and (4) innovative management and policy options that provide multiple {\textquotedblleft}wins{\textquotedblright} for land, climate, and biodiversity, thus enabling global development and food security goals to be achieved.

}, doi = {doi:10.1002/fee.1530}, url = {files/bibliography/17-023.pdf}, author = {Nicholas Webb and Marshall, Nadine and Stringer, Lindsay and Reed, Mark and A. Chappell and Jeffrey E. Herrick} } @proceedings {JRN54571, title = {Land degradation, monitoring, and adapting land management for sustainability}, year = {2016}, month = {01/2016}, publisher = {American Association for the Advancement of Science Meeting}, address = {Washington, DC}, abstract = {Land degradation impacts on agricultural production and other ecosystem services often far exceed those of climate change, yet these impacts are largely ignored. In September, the United Nations adopted a {\textquotedblleft}land degradation neutrality{\textquotedblright} target as part of its Sustainable Development Agenda. This paper will briefly review the role of soil biodiversity in meeting this target, and introduce a global Land-Potential Knowledge System (LandPKS). The LandPKS is a suite of interactive apps that allows anyone with a mobile phone to access and share global and local knowledge and information about sustainable land management. This is the first global open source, open data system that allows users to identify the specific information that is relevant to the unique characteristics of their land, thanks to the ability to use the phone to collect soil and location information, and the power of cloud-based global knowledge bases, databases, and computing power. The system also allows users to easily monitor changes in their land, and to instantly store, access, visualize and share their monitoring data both on the phone and through a web portal. The paper concludes with a discussion of the power of open source, open data systems for accelerating the development, testing and adoption of the innovative management systems, system that will be necessary to use soil biology to limit land degradation and support restoration in the context of a rapidly changing climate. }, author = {Jeffrey E. Herrick} } @article {JRN54559, title = {The Land-Potential Knowledge System (LandPKS): mobile apps and collaboration for optimizing climate change investments}, journal = {Ecosystem Health and Sustainability}, volume = {2}, year = {2016}, month = {03/2016}, chapter = {e01209}, abstract = {

Massive investments in climate change mitigation and adaptation are projected during coming decades.\  Many of these investments will seek to modify how land is managed. The return on both types of investments can be increased through an understanding of land potential: the potential of the land to support primary production and ecosystem services, and its resilience. A Land-Potential Knowledge System (LandPKS) is being developed and implemented to provide individual users with point-based estimates of land potential based on the integration of simple, geo-tagged user inputs with cloud-based information and knowledge. This system will rely on mobile phones for knowledge and information exchange, and use cloud computing to integrate, interpret, and access relevant knowledge and information, including local knowledge about land with similar potential. The system will initially provide management options based on long-term land potential, which depends on climate, topography, and relatively static soil properties, such as soil texture, depth, and mineralogy. Future modules will provide more specific management information based on the status of relatively dynamic soil properties such as organic matter and nutrient content, and of weather. The paper includes a discussion of how this system can be used to help distinguish between meteorological and edaphic drought.

}, keywords = {agriculture, analytics, crowdsourcing, expert systems, extension, knowledge management, land evaulation, land-use planning, mobile apps, sustainability, sustainable land managemen}, doi = {10.1002/ehs2.1209}, url = {/files/bibliography/16-007.pdf}, author = {Jeffrey E. Herrick and Beh, Adam and Barrios, E. and Coetzee, M and Bouvier, I. and Dent, D. and Emile H. Elias and Hengl, T. and Jason W. Karl and H. Liniger and Matuszak, John and Nudungu, L. and Obersteiner, M. and Shephers, K. and K.C. Urama and van der Bosch, R. and Nicholas Webb} } @conference {JRN54639, title = {Landscape soil variability in relatively static and dynamic properties in arid and semi-arid ecosystems: do they matter for restoration?}, booktitle = {2016 Ecological Society of America Meeting}, year = {2016}, month = {08/2016}, publisher = {2016 Ecological Society of America Meeting}, organization = {2016 Ecological Society of America Meeting}, address = {Fort lauderdale, FL}, abstract = {
Background/Question/Methods:
Soils matter for restoration. Or do they? This paper takes a process-based approach to this question, using a combination of published literature, pedotransfer functions, and several datasets where a range of relatively static and dynamic soil properties were measured on four different soil types in relatively undegraded and degraded ecological states in the four northern Chihuahuan Desert ecological sites: Sandy, Shallow Sandy, Gyp Upland and Clay Loam. \ Measured soil properties included soil texture, aggregate stability, water infiltration capacity, bulk density, penetrometer resistance, and soil organic carbon.
Results/Conclusions:\ 
Like so many questions in ecology, the answer is {\textquotedblleft}it depends{\textquotedblright}. It depends on the climate. It depends on what is being restored. And it depends on the soil property: how much does it matter to restoration success, how much does it vary naturally in the target landscape, and to what extent has the soil property been modified by degradation, and to what extent can it be enhanced prior to or during vegetation establishment? Our analyses, supported by additional published studies, show that while it is nearly always important to consider relatively static soil properties, such as soil texture, when planning restoration in semi-arid environments, the relative importance of dynamic soil properties varies widely across the landscape. The cost-effectiveness and success rate of restoration projects may be improved by careful consideration of when, where and what soil properties need to be considered in both selecting appropriate restoration treatments, and targeting these treatments to those parts of the landscape with the greatest potential for success. We conclude with a brief description of how existing assessment systems, including State and Transition Models, Interpreting Indicators of Rangeland Health, and Pedoderm Pattern Classes, can be used together to rapidly assess the status of key dynamic soil properties, and how the Land-Potential Knowledge System (LandPKS) can be used to rapidly describe and document relatively static properties using mobile phone apps.
}, author = {Jeffrey E. Herrick and S. W. Salley and Brandon T Bestelmeyer and Joel R. Brown and S.A. Wills} } @article {JRN54595, title = {Leaf litter decomposition is rapidly enhanced by the co-occurrence of monsoon rainfall and soil-litter mixing across a gradient of coppice dune development in the Chihuahuan Desert}, journal = {Journal of Arid Environments}, volume = {129}, year = {2016}, pages = {111-118}, abstract = {

Shrub encroachment, a common occurrence in drylands over the past 150 years, has the potential to alter the redistribution of soil and soil resources by wind and water. This may affect decomposition via soillitter mixing (SLM). SLM can accelerate decomposition, but its contributions and relationship with abiotic controls, particularly in the context of shrub encroachment, are unknown. To better understand the spatiotemporal relationships between decomposition and shrub encroachment, we conducted a 24 month decomposition study aimed at understanding how placement of litter on either up or downwind sides of dunes in association dune volume affected litter decomposition. There was little decomposition in the first six months of the experiment, with 97.2\% of mass remaining despite high exposure to solar radiation. Decay occurred in synchrony with monsoons and SLM, suggesting precipitation during the monsoon season plays an important role in facilitating both SLM and decomposition. Litter placements across a gradient of shrub volumes had no effect on decomposition rates and SLM, but litter placement on the downwind side of dunes had a positive influence on soil-microbial film development. Ultimately, monsoons rainfall and SLM promoted decomposition across a gradient of shrub encroachment in this dryland ecosystem.

}, keywords = {biogeochemical cycling, carbon cycling, litter decomposition, nutrient cycling, photodegradation, Prosopis, shrub encroachment}, doi = {10.1016/j.jaridenv.2016.02.014}, url = {files/bibliography/JRN00651.pdf}, author = {Hewins, Daniel B. and Heather L. Throop} } @proceedings {JRN54579, title = {The Land Potential Knowledge System: Application of earth observation data for sustainable land management}, year = {2016}, month = {06/2016}, address = {Naivasha, Kenya}, abstract = {

Africa is facing numerous challenges including a rapidly growing population, soil erosion, declining soil fertility and climate change. In the face of all these problems, the need to feed the growing population has led to expansion of land for agriculture and pasture production rather than increasing productivity. Available land must produce more food and pasture to meet the growing demand while\  conserving soil resources, reducing erosion risk, and improving the overall resilience of the land to produce and sustain current and future ecosystem services. Due to climate change, systems and phenologies are changing. With already stressed coping strategies, decision makers at management and policy levels together with local communities are often forced to make serious land use decisions with incomplete knowledge and information.

}, author = {Ndungu, L. and Jeffrey E. Herrick and Beh, Adam and Wahome, A. and Sande, S.} } @article {JRN54562, title = {A long-term analysis of the historical dry boundary for the Great Plains of North America: Implications of climatic variability and climatic change on temporal and spatial patterns in soil moisture}, journal = {Geoderma}, volume = {274}, year = {2016}, month = {07/2016}, pages = {104-113}, chapter = {104}, abstract = {

The boundary between the humid eastern and the arid western United States is of great economic interest and historic intrigue. Areas to the east of this geographic boundary have historically enjoyed more favorable rainfall, fertile soil, and reliable surface water, permitting conventional agriculture to flourish over a surprisingly large percentage of the eastern Great Plains. The expansion of population and agriculture during the nineteenth century across the Great Plains of North America tested the extent to which row crop agriculture could be successful in areas where year-to-year rainfall was unreliable. In this paper, we have quantified the historic variability of soil moisture and hydrologic conditioning resulting from climatic variability in the Great Plains by showing regions that historically demonstrate reliable precipitation, identifying an extent for the arid regions of the United States based on modeled soil moisture. We demonstrate that long-term climate and climate variability are reflected in the depth and concentration of the calcic soil properties. From a practical standpoint, our work suggests that soils with higher water holding capacity can dampen periodic short-term rainfall deficits likewise soils with lower water holding capacity can exhibit edaphic drought during otherwise normal years.

}, keywords = {Calcic soils, climatic variability, Newhall Simulation Model, North American Great Plains, soil moisture}, doi = {10.1016/j.geoderma.2016.03.020}, url = {/files/bibliography/16-009.pdf}, author = {S. W. Salley and Sleezer, Richard and Bergstrom, Robert and Martin, Patrick and E. Kelly} } @article {JRN54885, title = {Large-Eddy Simulations of Dust Devils and Convective Vortices}, journal = {Space Science Reviews}, volume = {203}, year = {2016}, month = {November 2016}, pages = {245-275}, chapter = {245}, abstract = {

In this review, we address the use of numerical computations called Large-Eddy Simulations (LES) to study dust devils, and the more general class of atmospheric phenomena they belong to (convective vortices). We describe the main elements of the LES methodology. We review the properties, statistics, and variability of dust devils and convective vortices resolved by LES in both terrestrial and Martian environments. The current challenges faced by modelers using LES for dust devils are also discussed in detail.

}, keywords = {Convective boundary layer, Convective vortices, dust devils, Large-Eddy Simulations}, doi = {10.1007/s11214-016-0284-x}, url = {files/bibliography/16-039.pdf}, author = {Aymeric Spiga and Erika Barth and Zhaolin Gu and Fabian Hoffmann and Junshi Ito and Bradley Jemmett-Smith and Martina Klose and Seiya Nishizawa and Siegfried Raasch and Scot Rafkin and Tetsuya Takemi and Daniel Tyler and Wei Wei} } @article {JRN54567, title = {Land Ecology Essay II: Thresholds, novel ecosystems, and the sanctity of history}, journal = {Rangelands}, volume = {37}, year = {2015}, month = {12/2015}, pages = {244-246}, chapter = {244}, abstract = {

Dr. Brandon Bestelmeyer is a research ecologist with the USDA Agricultural Research Service{\textquoteright}s Jornada Experimental Range and the Jornada Basin LTER at New Mexico State University in Las Cruces, New Mexico. He regularly writes about rangeland issues on the Land Ecology blog.

To read more of Brandon{\textquoteright}s essays, visit http://landecology.org/.

{\textquotedblleft}Land ecology{\textquotedblright} honors the holistic approach to the knowledge needed to support land stewardship into our increasingly uncertain future. Here we share an expanded version of one of Brandon{\textquoteright}s recent essays.

}, keywords = {Land Ecology, novel ecosystems, Sanctity of History, thresholds}, doi = {10.1016/j.rala.2015.10.009}, url = {/files/bibliography/15-024.pdf}, author = {Brandon T Bestelmeyer} } @article {JRN54568, title = {Land Ecology Essay I: The siren song of the finish line}, journal = {Rangelands}, volume = {37}, year = {2015}, month = {12/2015}, pages = {241-243}, chapter = {241}, abstract = {

As the National Cooperative Soils Survey nears the completion of initial mapping and description activities, the options for next steps are being considered. One option is to deploy new and emerging mapping technologies for existing and refined concepts of soil behavior to create more precise maps of the spatial distribution of soil properties. Another option is to focus efforts on interpreting existing soils information for new land use and management options, and for a new group of users. We suggest that the greatest benefits are to be gained from a very localized, specific implementation of new mapping technologies and a major, broad effort on new interpretations of existing information, particularly the implementation of an Ecological Site Initiative.

}, doi = {10.1016/j.rala.2015.10.005}, url = {/files/bibliography/15-025.pdf}, author = {Joel R. Brown and David Smith} } @article {JRN54392, title = {Linked hydrologic and social systems that support resilience of traditional irrigation communities}, journal = {Hydrology and Earth System Sciences}, volume = {19}, year = {2015}, month = {01/2015}, pages = {293-307}, chapter = {293}, abstract = {

Southwestern US irrigated landscapes are facing upheaval due to water scarcity and land use conversion associated with climate change, population growth, and changing economics. In the traditionally irrigated valleys of northern New Mexico, these stresses, as well as instances of community longevity in the face of these stresses, are apparent. Human systems have interacted with hydrologic processes over the last 400 years in river-fed irrigated valleys to create linked systems. In this study, we ask if concurrent data from multiple disciplines could show that human-adapted hydrologic and socioeconomic systems have created conditions for resilience. Various types of resiliencies are evident in the communities. Traditional local knowledge about the hydrosocial cycle of community water management and ability to adopt new water management practices is a key response to disturbances such as low water supply from drought. Livestock producers have retained their irrigated land by adapting: changing from sheep to cattle and securing income from outside their livestock operations. Labor-intensive crops decreased as off-farm employment opportunities became available. Hydrologic resilience of the system can be affected by both human and natural elements. We find, for example, that there are multiple hydrologic benefits of traditional irrigation system water seepage: it recharges the groundwater that recharges rivers, supports threatened biodiversity by maintaining riparian vegetation, and ameliorates impacts of climate change by prolonging streamflow hydrographs. Human decisions to transfer water out of agriculture or change irrigation management, as well as natural changes such as long-term drought or climate change, can result in reduced seepage and the benefits it provides. We have worked with the communities to translate the multidisciplinary dimensions of these systems into a common language of causal loop diagrams, which form the basis for modeling future scenarios to identify thresholds and tipping points of sustainability. Early indications are that these systems, though not immune to upheaval, have astonishing resilience.

}, doi = {10.5194/hess-19-293-2015}, url = {/files/bibliography/15-016.pdf}, author = {Alexander Fernald and Guldan, Steve and Ken Boykin and Andr{\'e}s F. Cibils and Gonzalez, M. and Hurd, B. and Lopez, S. and Carlos Ochoa and Melchor Ortiz and Rivera, J. and Rodriguez, S. and Caitriana Steele} } @conference {JRN54505, title = {LTAR linkages with other research networks: Capitalizing on network interconnections}, booktitle = {American Geophysical Union Fall Meeting}, year = {2015}, month = {12/2015}, publisher = {AGU}, organization = {AGU}, address = {San Francisco, CA}, abstract = {

Agro-ecosystem Research (LTAR) Network, the National Science Foundation{\textquoteright}s Long Term Ecological Research (LTER) Network, the National Ecological Observation Network (NEON), and the USDA{\textquoteright}s Climate Hub Network. Each of these networks has distinct functions, missions, operational characteristics, and distinct scientific and management sub-cultures (though some are fairly new and developing). Some are a fairly independent collection of research sites functioning as a network in name only, and others are truly working to develop a research synergy that could be holistic and uniquely productive. All have real scientific value, and collectively represent an investment in US research infrastructure in biology and agriculture in excess of $3B. To effectively utilize and exploit this unique research infrastructure will require a concerted effort to meld attributes of each to the benefits of their common stakeholders. Real opportunities exist to collectively utilize this infrastructure to address grand research challenges.

}, author = {Kris Havstad} } @article {JRN54145, title = {Legacy effects in linked ecological{\textendash}soil{\textendash} geomorphic systems of drylands}, journal = {Frontiers in Ecology and the Environment}, volume = {13}, year = {2015}, month = {02/2015}, pages = {13-19}, chapter = {13}, abstract = {

A legacy effect refers to the impacts that previous conditions have on current processes or properties. Legacies have been recognized by many disciplines, from physiology and ecology to anthropology and geology. Within the context of climatic change, ecological legacies in drylands (eg vegetative patterns) result from feedbacks between biotic, soil, and geomorphic processes that operate at multiple spatial and temporal scales. Legacy effects depend on (1) the magnitude of the original phenomenon, (2) the time since the occurrence of the phenomenon, and (3) the sensitivity of the ecological{\textendash}soil{\textendash}geomorphic system to change. Here we present a conceptual framework for legacy effects at short-term (days to months), medium-term (years to decades), and long-term (centuries to millennia) timescales, which reveals the ubiquity of such effects in drylands across research disciplines.

}, keywords = {biotic process, conceptual framework, dryland systems, ecological legacies, ecological systems, geomorphic processes, legacy effects, soil processes}, doi = {10.1890/140269}, url = {/files/bibliography/15-002.pdf}, author = {Curtis H. Monger and O. E. Sala and Danielle Duni and Goldfus, Haim and Meir, Isaac A. and Poch, Rosa M. and Heather L. Throop and Enrique Vivoni} } @conference {JRN54421, title = {Location, location, location: The influence of plant neighborhood configuration on grass-shrub interactions}, booktitle = {100th Annual Meeting of the Ecological Society of America (ESA)}, year = {2015}, month = {08/2015}, abstract = {

State transition from perennial grassland to shrubland or woodland is often synonymous with land degradation and desertification in arid and semiarid ecosystems. These physiognomic\  transitions markedly alter rates and dynamics of ecological processes and the ability of ecosystems to provide services of value to society. Land managers and other stakeholders could benefit from research designed to identify vegetative structural properties that forecast when ecological sites might be at risk for state changes. We sought to determine such indicators via removal experiments conducted along an extant\ Bouteloua eriopoda-to-Prosopis glandulosa\ encroachment gradient at the Jornada Basin LTER site in the northern Chihuahuan Desert. Ninety plots centered upon\ B. eriopoda\ patches were established along the grassland-to-shrubland gradient. The size of and distance to all\ P. glandulosa\ individuals within a 5 m radius was recorded and aboveground shrub biomass was estimated using site- and species-specific allometric regression (R2\ = 0.89). Peak season\ B. eriopoda\ biomass was quantified in 2010.\ P. glandulosa\ shrubs within 5 m of half of grass plots (n=45) were then killed via foliar herbicide in early summer 2011.\ B. eriopodabiomass was again quantified at the end of the subsequent growing seasons.


Results/Conclusions:\  B. eriopoda\ cover ranged from 26.3\% to 3.6\% along the grassland-to-shrubland gradient, and declined exponentially as\ P. glandulosa\ cover and biomass increased linearly from 2.2\% and \<200 g \ to 17.9\% and \> 400 g m-2. In 2013, mean (SE)\ B. eriopoda\ productivity in plots with\ P. glandulosa\ neighbors removed was 94.8 (6.1) g m-2\ y-1, compared to 52.9 (6.4) in plots with shrub neighbors intact (p \< 0.0001). Grass response to shrub removal was significant in the grassland and shrubland portions of the gradient, more so in the latter [shrub removal vs. control = 111.8 (21.1) vs. 41.6 (8.2); p \< 0.0001], than in the former [84.5 (6.6) vs. 60.8 (12.4) g m-2\ y-1; p = 0.001]. However,\ B. eriopodaproductivity did not differ between the control and shrub removal treatments in the ecotone (shrub biomass 200-400 g). This was due to high variability in grass production in the control plots (range 20.9 g {\textendash} 212.2 g). Variability in grass ANPP may therefore be a more reliable indicator of impending state-transitions than mean ANPP. Forthcoming analyses will examine how the structure (e.g. size, number, density) of the shrub neighborhood influences grass productivity.\  Abstract $\#$ COS 45-4.

}, author = {Nathan Pierce and Steven R. Archer and Brandon T Bestelmeyer} } @conference {JRN54439, title = {Landscape restoration supports genetic connectivity among populations of a keystone species}, booktitle = {99th Annual Meeting of the Ecological Society of America}, year = {2014}, month = {08/2014}, address = {Sacramento, CA}, abstract = {

Background/Question/Methods:\  Restoration of habitats that minimize dispersal costs could be essential for supporting population connectivity and the recovery of wildlife species. In the Chihuahuan Desert of southern New Mexico, grasslands have been replaced with shrubs due to overgrazing, drought, and lack of fire. We tested the hypothesis that landscape-scale restoration of grasslands affects gene flow among populations of banner-tailed kangaroo rats (Dipodomys spectabilis).\ Dipodomys spectabilis\ is a keystone species that creates habitat heterogeneity and alters plant and animal communities. Restoration treatments are known to reduce shrub cover and increase grass cover, and the density of\ D. spectabilis\ responds positively to treatments. However, the response of\ D. spectabilis\ is strongly time-lagged due to inadequate connectivity to source populations. Insight into effects of landscape structure on dispersal could be helpful for targeting areas for future restoration treatments. We used seven microsatellite markers and landscape resistance models to examine whether restored grasslands and other landscape features (e.g., waterways, roads, slope) affect the degree of genetic divergence among 20\ D. spectabilis\ populations.

Results/Conclusions:\  Pairwise genetic divergence (FST) varied from 0{\textendash}0.18, suggesting that the level of gene flow varied widely across the landscape. There was a strong pattern of isolation by distance using a simple model of Euclidean distances. However, landscape resistance models were generally more supported than a Euclidean distance model for explaining variation in genetic divergence. The most-supported resistance model accounted for restored grasslands and no other landscape features, suggesting restoration treatments facilitate gene flow. There was also some evidence that gene flow was restricted by roads and waterways. Populations east and west of the Rio Grande and Interstate-25 corridor were strongly differentiated. Overall, our results suggest that landscape-scale efforts to restore grasslands support dispersal and gene flow among populations of\ D. spectabilis. Targeting future restoration sites near other treated areas may be an effective approach for facilitating the recovery of\ D. spectabilis\ populations.\  Abstract $\#$ PS 27-126.

}, author = {Brad Cosentino and Robert L. Schooley and Brandon T Bestelmeyer and McCarthy, A. and Sierzega, Kevin} } @article {JRN53950, title = {The landscape of fear: The missing link to understand top-down and bottom-up controls of prey abundance?}, journal = {Ecology}, volume = {5}, year = {2014}, month = {06/2014}, pages = {1141-1152}, chapter = {1141}, abstract = {

Identifying factors that may be responsible for affecting and possibly regulating the size of animal populations is a cornerstone in understanding population ecology.\  The main factors that are thought to influence population size are either resources (bottom-up), predation, (top-down), or interspecific competition (called here- parallel influences).\  However, studies of these effects have produced highly variable and often contradictory results regarding the relative strengths and influence of these factors. These varied results are often interpreted as indicating {\textquotedblleft}shifting control{\textquotedblright} among the three forces or existence of a complex, non-linear relationship among precipitation, resource availability, predation, and competition.\  We argue here that these interpretations suggest a {\textquotedblleft}missing link{\textquotedblright} in our understanding of predator-prey dynamics.\  We explore whether the landscape of fear model can clarify the inconsistencies and help us understand the roles, extent, and possible interactions of top-down, bottom-up, and parallel factors on prey population abundance.\  We propose various predictions derived from the landscape of fear model.\  For a single species, we suggest that as the makeup of the landscape of fear changes from relatively safe to relatively risky, bottom up impacts switch from comparatively strong to weak as top-down impacts go from weak to strong.\  For two or more species, interspecific competitive interactions produce various combinations of bottom-up, top-down, and parallel impacts depending on which competing species is superior and whether their landscapes of fear are shared or distinctive.\  We contend that these predications successfully explain many of the complex and contradictory results of current research.\  We end by testing some of these predictions based on long-term data for small mammals from the Chihuahuan Desert in the U.S. and M{\'e}xico.\  We conclude that the landscape of fear model does provide reasonable explanations for many of the results found and should be tested further and that this model has the possibility of being the {\textquotedblleft}missing link{\textquotedblright} in understanding bottom-up, top-down and parallel effects on population dynamics.

}, keywords = {bottom-up, Chihuahuan Desert, Dipodomys merriami, Durango, fox abundance, landscape of fear, Mapimi Biosphere Reserve, Merriami Kangaroo rat, parallel control effects, patch dynamics, predation risk, species conservation and management, top-down control, United States and Mexico}, doi = {10.1890/13-1083.1}, url = {/files/bibliography/14-012.pdf}, author = {John W. Laundre and Lucina Hern{\'a}ndez and Lopez Medina, Pete and A. Campanella and Lopez-Portilla, Jorge and Gonzales-Romero, Alberto and Grajales-Tam, Karina M and Burke, Anna M and Peg Gronemeyer and Dawn M. Browning} } @article {49852, title = {Land degradation and climate change: A sin of omission?}, journal = {Frontiers in Ecology and the Environment}, volume = {11}, year = {2013}, month = {08/2013}, pages = {283}, type = {Editorial}, chapter = {283}, abstract = {

Although the environmental and social impacts of climate change may exceed those of land degradation at some point in the future, the effects of land degradation are occurring now. Furthermore, while climate-change mitigation requires global solutions, individuals and communities can successfully reduce land degradation at the local level. We offer two recommendations. First, the current focus on climate-change research should be complemented by research on ecological processes associated with land degradation and the development of solutions based on an understanding of these processes. Second, an enhanced understanding of land potential is necessary to target\  imited resources to increase agricultural production, conserve biodiversity, promote recovery of degraded lands, and adapt to and mitigate the impacts of climate change.

}, doi = {10.1890/1540-9295-11.6.283}, url = {/files/bibliography/13-024.pdf}, author = {Jeffrey E. Herrick and O. E. Sala and Jason W. Karl} } @proceedings {49851, title = {A land-potential knowledge system (LandPKS) based on local and scientific knowledge of land productivity and resilience}, year = {2013}, month = {04/2013}, pages = {314-318}, publisher = {UNCDD}, address = {Bonn, Germany}, abstract = {

Economic assessment of land use change in drylands depends on understanding potential productivity, degradation resistance and resilience, all of which vary widely and are often ignored. Rapidly increasing demand, together with new technologies, migration and global capital mobility are driving dramatic land use changes. Management practices that are productive and sustainable on one type of land may, when applied to adjacent lands, result in irreversible degradation due to differences in soil, topography and climate. Conversely, lessons learned on land separated by thousands of kilometers are often relevant, provided that similar conditions exist. New technologies, including cloud-computing, digital soil mapping, GPS-enabled camera phones, and mobile \‘apps\’ now provide the opportunity to gather, integrate and share new knowledge and information about land potential, while global databases make existing knowledge more accessible and easier to match to relevant conditions. A new \“Land-Potential Knowledge System\” (LandPKS) will integrate existing natural resource databases with targeted field data collection of knowledge and information using new cell phone-based tools. An understanding of land potential can be used to determine where: (1) land is not meeting its productive potential (for all ecosystem services), (2) unrealistic expectations are driving unsustainable development investments, and (3) proposed intensification is likely to lead to irreversible degradation. Decision tools will support land use planning and targeted interventions by governments, development and conservation organizations and farmers. Knowledge of land potential can dramatically increase the return on investment by focusing resources on sustainable land uses and management strategies.

}, keywords = {decision support system, mobile apps, mobile phones, soil, sustainable land management}, url = {/files/bibliography/13-011.pdf}, author = {Jeffrey E. Herrick and K.C. Urama and Jason W. Karl and Boos, John and Mari-Vaughn V. Johnson and Keith Shepherd and Hempel, Jon and Brandon T Bestelmeyer and J. Davis and Guerra, Jose Larson and Kosnik, Chris and D.W. Kimiti and Losinyen, Abraham and Muller, Kit and Norfleet, L.M. and Ozor, Nicholas and Reinsch, Thomas and J. Sarukhan and West, L.T.} } @inbook {49857, title = {Landscape Diversity}, booktitle = {Encyclopedia of Biodiversity}, volume = {4}, year = {2013}, pages = {476-487}, publisher = {Academic Press}, organization = {Academic Press}, edition = {2}, address = {Waltham, MA}, abstract = {

While biodiversity is usually considered at the species level, maintenance of biodiversity requires management at higher levels of organization, particularly at the landscape scale. It is difficult to manage for each threatened species individually. Alternatively, management can focus on the ecosystems that contain these species, and on the landscapes in which ecosystems are found. There are three basic characteristics of landscapes that affect their diversity: structure, function, and dynamics. Structure is the most well-understood element of landscapes. It is also the most obvious{\textemdash}nearly any aerial view will show a mixture of different landforms, habitats, or vegetation types. The characteristics of patches and the spatial relationships among patches are important components of landscapes. Function is concerned with interactions among the spatial elements of a landscape, including flows of energy, materials, and species among patches. Landscape dynamics includes characteristics of both structure and function in order to examine changes in pattern and process over time. This article discusses each element in turn, and also considers the underlying determinants of landscape structure, including environmental heterogeneity and disturbance patterns. We then discuss issues in biodiversity management, and conclude with a case study of landscape diversity at the Sevilleta National Wildlife Refuge Long-Term Ecological Research site in central New Mexico, United States.

}, doi = {10.1016/B978-0-12-384719-5.00084-8}, url = {files/bibliography/13-009.pdf}, author = {Debra C. Peters and Sarah Goslee and S.L. Collins and J. R. Gosz} } @inbook {JRN52675, title = {Long-term research across sites, ecosystems, and disciplines: synthesis and research needs}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {226-233}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {17}, address = {Springfield, Virginia}, abstract = {

The EcoTrends Project is one of the first attempts to standardize, simplify, integrate, and visualize data from diverse terrestrial, aquatic, and marine ecosystems to promote understanding and synthesis by a broad audience. This chapter discusses key scientific results from this project, describes developing conceptual and operational frameworks for cross-site synthesis, and provides recommendations for future research. Key results are: mean air temperature has increased at 24 sites, and annual precipitation has increased at 9 sites with no obvious spatial distribution in either climate variable. Trends in atmospheric chemistry show clear patterns across the continent with reduced deposition of nitrate and sulfate in precipitation through time in the eastern U.S. compared with the West. Patterns in stream water chemistry across sites do not reflect broad-scale patterns in atmospheric chemistry; thus local conditions have strong influences on chemical inputs to and losses from streams. Human population density has increased at all sites, although at different rates. Biotic data are often idiosyncratic in that they reflect high spatial and temporal variability inherent in biological phenomenon.\  It is proposed that cross-site synthesis studies should integrate three aspects of ecological research: depth (individual sites being studied in great detail), length (data being collected over long periods), and breadth (phenomena being studied across broad spatial extents).\  The strongest recommendation for future research is to make data and associated metadata easily accessible to and usable by others.

}, 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/13-029-17.pdf}, author = {Debra C. Peters} } @inbook {JRN52669, title = {Long-term trends in climate and climate-related drivers}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {81-114}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {11}, address = {Springfield, Virginia}, abstract = {

This chapter shows long-term data and trends in climate and climate-related drivers for each site.\  It contains a brief introduction to the topic, and methods of measurements, selection of variables, and their data source. It consists primarily of a large number of figures showing long-term data for different variables.\  On land, air temperature (mean, minimum, and maximum), precipitation, Palmer Drought Severity Index, and Walter-Lieth climate diagrams are selected.\  In water, streamflow, sea level, ice duration, water clarity, and water temperature are selected.\  Two types of graphs are included to show trends in the variables and to provide a sense of change across a range of spatial scales (continent, site) for each variable: maps at continental scale showing either the mean across years or the slope of the regression line (if significant) across time, and site-scale data through time.\  Air temperatures are increasing in at least one variable (minimum, mean, maximum) for 27 of the 50 sites.\  Sea level is increasing at all 11 coastal sites.\  Observing these trends in climate across multiple ecosystems across continents is only possible with spatially extensive, long-term data collection and analysis, such as provided by the EcoTrends Project.

}, 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/13-029-11.pdf}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J. Morgan and A. K. Knapp and T. K. Kratz and Mark D. Ohman} } @book {JRN52662, title = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {378}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, address = {Springfield, Virginia}, abstract = {

The Eco Trends Editorial Committee sorted through vast amounts of historical and ongoing data from 50 ecological sites in the continental United States including Alaska, several islands, and Antarctica to present in a logical format the variables commonly collected.\  This report presents a subset of data and variables from these sites and illustrates through detailed examples the value of comparing long-term data from different ecosystem types. This work provides cross-site comparisons of ecological responses to global change drivers, as well as long-term trends in global change drivers and responses at site and continetal scales.\  Site descriptions and detailed data also are provided in the appendix sections.

\⇒ This book is available for download (PDF format) below

\⇒ Available from http://www.ars.usda.gov/is/np/indexpubs.html

\⇒ Copies may be purchased in various formats (microfiche, photocopy, CD, print on demand) from the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161, 800-553-6847, www.ntis.gov

Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change\  (download PDF - 313 MB)

Download the book in PDF in it\&$\#$39;s entirety (above) or by section (below)

Contents

Introduction to Cross-Site Comparisons and History and Organization of the EcoTrends Project\  (8.29 MB)

Cross-Site Comparisons of Ecological Responses to Global Change Drivers\  (21.8 MB)


Long-Term Trends in Global Change Drivers and Responses at Site and Continental Scales\  (197 MB)


Appendices \& Index\  (79 MB)

}, 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 Bk.pdf}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J. Morgan and A. K. Knapp and T. K. Kratz and Mark D. Ohman and R. B. Waide and Jin Yao} } @inbook {JRN52676, title = {Long-term trends in ecological systems: An introduction to cross-site comparisons and relevance to global change studies}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {1-20}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {1}, address = {Springfield, Virginia}, abstract = {

This chapter explains the importance of long-term data to ecological studies and the needs of creating a way to provide accessible and comparable multi-site long-term data. The Earth{\textquoteright}s environment is changing in many ways at local, regional, and global scales. Dramatic changes have occurred in climate, land cover, and habitat availability over the past several centuries. Long-term data (\> 10 years) are needed to assess the rate and direction of change, to distinguish directional trends in these changes (e.g., persistent increases or decreases) from short-term variability (e.g., multi-year cycles), and to forecast environmental conditions in the future.\  It also sets up the stage for the rest of the chapters in the book, presenting the purposes, audience and practical applications of the book, explaining how the study sites, variables, and data sets are selected, and how the data are presented and analyzed, and laying out the organization of the book.

}, 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/13-029-1.pdf}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J. Morgan and A. K. Knapp and T. K. Kratz and Mark D. Ohman and R. B. Waide and Jin Yao} } @inbook {JRN52671, title = {Long-term trends in human demography and economy across sites}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {162-190}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {13}, address = {Springfield, Virginia}, abstract = {

This chapter shows long-term data and trends in human demography and economy for each site.\  It contains a brief introduction to the topic, and methods of measurements, selection of variables, and their data source. It consists primarily of a large number of figures showing long-term data for different variables.\  Total population, the percentage of the population living in urban areas, and the density of people in the counties associated with each site are selected.\  Four economic variables fore each focal county of a site are also selected: the percentage of the population employed by one of four economic sectors: commercial industries, farming, manufacturing, and service industries.\  Two types of graphs are included to show change through time across a range of spatial scale for each variable: maps of continental scale showing either the \% change in total population for four time periods (1800 to 1850; 1850 to 1900, 1900 to 1950, 1950 to 2000) or the \% of the population that was urban in each of four time periods (1850, 1900, 1950, 2000); and maps and graphs showing site-scale data through time. The settlement of the country occurred from the east coast and then to the west coast by 1900, and then to the interior between 1900 and 1950. Losses of population in the Midwest occurred between 1950 and 2000. Most areas of the country had a high percentage of urban population by 1950. Urbanization continued for most of the country until 2000 with the Northeast, Appalachian Mountains, and northern Wisconsin providing notable exceptions.

}, 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/13-029-13.pdf}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J. Morgan and A. K. Knapp and T. K. Kratz and Mark D. Ohman} } @inbook {JRN52670, title = {Long-term trends in precipitation and surface water chemistry}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {115-161}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {12}, address = {Springfield, Virginia}, abstract = {

This chapter shows long-term data and trends in precipitation and surface water chemistry for each site.\  It contains a brief introduction to the topic, and methods of measurements, selection of variables, and their data source. It consists primarily of a large number of figures showing long-term data for different variables.\  Volume-weighted concentration (mg/L) and area-based wet deposition (kg/ha) from precipitation, and concentration in surface water (mg/L) of nitrogen (as nitrate and ammonium), sulfur (as sulfate), chloride, and calcium are selected.\  Two types of graphs are included to show trends in the variables and to provide a sense of change across a range of spatial scales (continent, site) for each variable: maps at continental scale showing either the mean across years or the slope of the regression line (if significant) across time, and site-scale data through time.\  Nitrate and sulfate deposition are decreasing in many Eastern sites, consistent with efforts to control emissions of acid-causing nitrogen and sulfur from power plants in this part of the country.

}, 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/13-029-12.pdf}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J. Morgan and A. K. Knapp and T. K. Kratz and Mark D. Ohman} } @inbook {JRN52672, title = {Long-term trends in production, abundance, and richness of plants and animals}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {191-205}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {14}, address = {Springfield, Virginia}, abstract = {

This chapter shows long-term data and trends in production, abundance, and richness of plants and animals for each site.\  It contains a brief introduction to the topic, and methods of measurements, selection of variables, and their data source. It consists primarily of a large number of figures showing long-term data for different variables.\  Net primary production, plant biomass and species richness, animal abundance and species richness are selected.\  Figure of site-scale data through time of each variable is shown, and a regression line is shown if the relationship is significant and the trend appears linear.\  The site graphs are shown on a continental map with similar sites to allow comparison among sites.\  At many sites, multiple locations are sampled for plant and animal dynamics. The large within-site variability in responses often overwhelms trends through time.\  Although plant response variables of ANPP, richness, and biomass are sampled for most sites to allow cross-site comparisons, animal response variables are more variable among sites with fewer comparable groups. These results indicate that each site selects representative trophic groups from the local ecosystems, instead of attempting to standardize across sites.\  The length of the time series also varies across sites which further complicates cross-site comparisons.

}, 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/13-029-14.pdf}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J. Morgan and A. K. Knapp and T. K. Kratz and Mark D. Ohman} } @proceedings {JRN54548, title = {Livestock production in a world with less grass}, volume = {p. 19-20}, year = {2012}, month = {05/2012}, publisher = {Wildland Shrub Symposium}, address = {Las Cruces, NM}, abstract = {The world{\textquoteright}s ice-free land surface is ~147.3x106 km2. Rangelands comprise 54\% of this area, ~80x106 km2. Only 16\%, 12.8x106 km2, of this rangeland type is classified as grassland. The predominant vegetation type is simply categorized as {\textquotedblleft}woody{\textquotedblright}, and currently covers 37.9x106 km2. Though grass dominated rangelands occur on all continents, it is wholly inaccurate to think of rangelands as characteristically {\textquotedblleft}grasslands{\textquotedblright}. In fact, the grasslands that exist are commonly in decline for a variety of reasons, though two dominant factors are the continued conversion of native landscapes to cropland and the encroachment of existing native landscapes by woody plants. Given that global cereal production is anticipated to increase by approximately 1 billion tons over the next 2 decades, the conversion of rangeland to cropland will likely continue unabated. Concurrently, continued land degradation, reduction or elimination of prescribed burning, and increased atmospheric CO2, as well as continuation of other drivers, will further promote expansion of woody plants. In parallel with these trends is the continued, stunningly rapid increase in global numbers of livestock over the past 5 decades. In 1960, global numbers of cattle, sheep and goats were ~2.4 B head. Today, global numbers of livestock are in excess of 3.0 B head. Given the escalating demands for red meat by the world{\textquoteright}s 7 B human inhabitants, especially driven by growing economies in Asia, this demand will likely not lessen. The Food and Agriculture Organization has estimated that by 2030 there will be 4.2 B head of livestock around the world. Though reliance on intensive livestock production systems has grown in recent decades, about 1/3rd of livestock worldwide are raised within extensive, grazing-based production systems. About 70\% of these animals are within rangeland systems in developing countries, a situation that contributes to the fact that 1 in 10 people around the world are engaged in animal husbandry. It should be evident that we are faced with the need to produce livestock in a world with less grass not only today, but for the decades ahead in the 21st century. This will require employing a number of management strategies that will utilize the predominately woody components of the worldwide forage base within our rangeland environments.}, author = {Kris Havstad and Richard E. Estell and D.M. Anderson and Scott T. Schrader and D. K. James and Andr{\'e}s F. Cibils} } @proceedings {JRN54543, title = {The land potential knowledge system (LandPKS): Increasing land productivity and resilience}, volume = {p. 64}, year = {2012}, month = {11/2012}, publisher = {African Technology Policy Studies}, address = {Addis Ababa, Ethiopia}, abstract = {Africa must significantly increase agricultural production to meet the needs of a growing population. Current efforts focus on intensifying production on currently used lands and expanding to un- or under-utilized lands. The success of both strategies requires understanding the land{\textquoteright}s potential productivity, and its resilience: its ability to resist or recover from degradation. Both potential productivity and resilience can vary widely across areas from less than a hectare to thousands of square kilometers, depending on soils, topography and climate. An understanding of land potential is therefore needed by governments for land use planning and climate change adaptation, and for negotiating land contracts that will ensure that a nation{\textquoteright}s productive capacity will be maintained. It is needed by national extension and international development organizations to target their investments. Finally, this understanding is needed by individual farmers to determine how to best feed their children today, while ensuring that future generations will also be able to feed themselves. Much of the necessary information and knowledge to understand land potential already exists in the scientific literature and as local knowledge, but is often not accessible or easily integrated and shared. Where the information and knowledge are accessible, the types of land to which they are relevant is often unclear. In some cases, the most similar soil and climate conditions (and therefore the best places to look for successful management strategies) may exist within a country, while in others the closest analog may be on a different continent. The USDA and ATPS have established a partnership to develop a Land-Potential Knowledge System (LandPKS) with initial support from USAID, following on an ongoing ATPS social innovation project supported by the Rockefeller Foundation. The LandPKS will use mobile phone technologies and web-based knowledge engine to allow policymakers and land managers to share and access the most current information and knowledge for their specific type of land. A secondary function of this system will be to directly connect farmers, including women, with nearby farmers who have developed innovative strategies that they have tested on the same type of land. It will also increase the value and efficiency of existing agricultural extension workers by providing them with the tools and information necessary to communicate more specific and timely recommendations to particular groups of farmers (e.g., providing information on drought management specifically to those farmers with soils that are the most sensitive to drought). Following the development of the knowledge engine and mobile phone applications (2013), LandPKS will be piloted in Kenya and Namibia (2014). These countries were selected because they include a broad range of biophysical conditions (soils and climate), large areas that are currently undergoing different types of land use change, a diversity of land ownership systems (communal, private and public), and very different levels of local knowledge, and management objectives, including both agricultural production and biodiversity conservation. Beginning in 2015, we expect to make LandPKS globally available. LandPKS is being designed to complement and increase the value of the work of a large number of other projects and initiatives, including AfSIS, and we look forward to developing new partnerships as the system evolves. Like many other social innovations, the development and implementation process will rely strongly on partnerships as the benefits of participating in the system are expected to vastly exceed adoption costs for both individuals and organizations.}, keywords = {ATPS, Innovative strategies, land information, Land potential knowledge system, Resilence, USDA}, url = {files/bibliography/12-LPKS-Herrick.pdf}, author = {Jeffrey E. Herrick and K.C. Urama and Boos, John and Jason W. Karl and Kosnik, Chris} } @article {49894, title = {Linking runoff and erosion dynamics to nutrient fluxes in a degrading dryland landscape}, journal = {Journal of Geophyscal Research}, volume = {117}, year = {2012}, pages = {1-16}, abstract = {

Current theories of land degradation assume that shifts in vegetation communities result in changes to the rates and patterns of water and sediment movement, which are vectors of nutrient redistribution. This nutrient redistribution is hypothesized to reinforce, through positive feedbacks, progressive vegetation changes toward a more degraded ecosystem. A key component of this theory, which is currently poorly resolved, is the relative role of runoff and erosion in driving nutrient fluxes from different vegetation types. We address this gap through a series of field-based, rainfall-simulation experiments designed to explore plant-level dynamics of runoff- and erosion-driven nutrient fluxes of N, P and K species. Our results highlight important linkages between physical and biogeochemical processes that are controlled by plant structure. We found that: 1) the magnitude of sediment-bound nutrient export is determined by the grain-size distribution of the eroded sediment and the total sediment yield; 2) the partitioning of nutrients in dissolved and sediment-bound form is determined by the availability and concentration of different nutrient species in the soil or rainfall; 3) these processes varied according to vegetation type and resulted in stark differences between degrading and invading plant communities. Specifically, we observed that grassland areas consistently exported the highest yields of sediment-bound N, P and K despite producing similar erosion rates to shrub and intershrub areas. Our results have implications for better understanding how grassland areas are being replaced by shrubs and provide insights into the mechanisms of continuing land degradation in drylands.

}, keywords = {erosion dynamics, hydrology, land degradation, nutrient fluxes, rainfall simulation, runoff dynamics}, doi = {10.1029/2012JG002071}, url = {files/bibliography/JRN00601.pdf}, author = {Michaelides, Katerina and Lister, Debbie and John Wainwright and A.J. Parsons} } @article {JRN54212, title = {Long-term experimental loss of foundation species: consequences for dynamics at ecotones across heterogeneous landscapes}, journal = {Ecosphere}, volume = {3}, year = {2012}, month = {03/2012}, pages = {1-23}, chapter = {Article 27}, abstract = {

Biome transition zones where species co-exist near their geographic limits are expected to be among the most responsive to changes in climate that result in mortality of foundation species. Long-term (.13 years) patterns in dominance and cover of functional types were examined following the annual experimental removal of one of three foundation species at an arid-semiarid biome transition zone.\  Objectives were to identify key processes influencing these patterns, and to predict future landscape-scale dynamics following mortality of different foundation species. Aboveground biomass of dominant species was removed from 334 m plots. Cover by species on control and removal plots was estimated annually in communities with a single dominant species, and in ecotonal communities with two dominant species across two types of ecotones (semiarid grassland-arid grassland, arid grassland-arid shrubland).\  For most species and functional types, trends in cover through time were related to the remaining species assemblages rather than to variable climatic conditions. In ecotonal communities, resident co-dominant species increased to dominance following the loss of a foundation species with little change in community composition. In mono-dominated communities, dominant species loss resulted in a shift to species that are currently sub-dominants of the same functional type as the species that was removed. \ Subdominant perennial grass and shrub species increased rapidly following removals in most grassland locations.\  Annuals and perennial forbs had variable cover values through time that were not clearly related to pulses in precipitation and were not synchronized across locations. The most common response regardless of the identity of the foundation species removed or the community type was an increase in cover by subdominant grasses and by the arid grass species (Bouteloua eriopoda). The rate of increase by B. eriopoda depended on initial cover, and resulted from both vegetative growth and seedling recruitment from other locations. Seed dispersal and seedling recruitment from other locations were not found for the semiarid grass, Bouteloua gracilis or the arid shrub, Larrea tridentata. Because B. eriopoda is more susceptible to shrub invasion, drought, and livestock grazing than the other two foundation species, widespread loss of either of the other species and subsequent increase in B. eriopoda is expected to result in an increase in landscape scale vulnerability to these environmental drivers. The extent and magnitude of this change invulnerability will depend on the ability of B. eriopoda to respond based on the micro-environmental conditions of the site regardless of which species (B. gracilis, L. tridentata) is lost.

}, keywords = {arid, biome transitions, Chihuahuan Desert, dominant species, experimental removals, grasslands, mortality, semiarid, Shorrgrass Steppe, shrublands}, doi = {10.1890/ES11-00273.1}, url = {/files/bibliography/12-042.pdf}, author = {Debra C. Peters and Jin Yao} } @article {49901, title = {Landform influences on the resistance of grasslands to shrub encroachment, Northern Chihuahuan Desert, USA}, journal = {Journal of Maps}, year = {2012}, month = {11/2012}, pages = {1-7, iFirst Article}, abstract = {

In arid and semiarid regions, vegetative boundaries are often strikingly similar to landform boundaries. However, it is not well documented whether landforms exert an influence on the resistance of desert grassland to shrub encroachment. Dominant grassland communities have been displaced by woody shrubs over the last 150 years in the Jornada Basin, southern New Mexico. Digital vegetation maps from 1858, 1915{\textendash}1916, 1928{\textendash}1929, 1938, and 1998, in conjunction with a detailed landform map, were analyzed in a Geographical Information System. The generated time series maps and spatial data compiled from these datasets were used to quantify the extent and rate that grasslands were replaced by shrubs on eight contiguous landforms. From this assessment, we generated a resistance index that revealed desert grasslands were least resistant (most susceptible) to shrub expansion on sandy landforms and bajadas and most resistant to shrub invasion on ephemerally flooded playas. This study demonstrates that landforms both provide the broad-scale background for detailed mechanistic studies and affect the sensitivity of grasslands to shrub encroachment.\ 

}, keywords = {arid geomorphology, Chihuahuan Desert, desertification, grassland resistance, shrub encroachment}, doi = {10.1080/17445647.2012.727593}, url = {/files/bibliography/12-027.pdf}, author = {Rachal, David M. and Curtis H. Monger and Gregory S. Okin and Debra C. Peters} } @article {49902, title = {Legacies of precipitation fluctuations on primary production: theory and data synthesis}, journal = {Philosophical Transactions of the Royal Society B}, volume = {367}, year = {2012}, month = {08/2012}, pages = {3135-3144}, chapter = {3135}, abstract = {Variability of above-ground net primary production (ANPP) of arid to sub-humid ecosystems displays a closer association with precipitation when considered across space (based on multiyear averages for different locations) than through time (based on year-to-year change at single locations). Here, we propose a theory of controls of ANPP based on four hypotheses about legacies of wet and dry years that explains space versus time differences in ANPP\–precipitation relationships. We tested the hypotheses using 16 long-term series of ANPP. We found that legacies revealed by the association of current- versus previous-year conditions through the temporal series occur across all ecosystem types from deserts to mesic grasslands. Therefore, previous-year precipitation and ANPP control a significant fraction of current-year production. We developed unified models for the controls of ANPP through space and time. The relative importance of current-versus previous-year precipitation changes along a gradient of mean annual precipitation with the importance of current-year PPT decreasing, whereas the importance of previous-year PPT remains constant as mean annual precipitation increases. Finally, our results suggest that ANPP will respond to climate-change-driven alterations in water availability and, more importantly, that the magnitude of the response will increase with time.}, keywords = {legacies, precipitation effects, primary production, spatial and temporal models}, doi = {10.1098/rstb.2011.0347}, url = {/files/bibliography/12-039.pdf}, author = {O. E. Sala and Laureano A. Gherardi and Lara Reichmann and Esteban Jobb{\'a}gy and Debra C. Peters} } @article {49906, title = {Landform and vegetation patch type moderate the effects of grazing-induced disturbance on carbon and nitrogen pools in a semi-arid woodland}, journal = {Plant and Soil}, volume = {360}, year = {2012}, month = {05/2012}, pages = {405-419}, chapter = {405}, abstract = {

Background and aims: Dryland soil organic carbon (C) pools account for a large portion of soil C globally, but their response to livestock grazing has been difficult to generalize. We hypothesized that some difficulty generalizing was due to spatial heterogeneity in dryland systems. We examined the importance of heterogeneity at vegetation and landform scales on the response of litter and soil C and nitrogen (N) to grazing.

Methods: Litter and soil C and N pools were quantified in different vegetation microsites (tree, shrub, open) and landform elements (dune, swale) across a grazing disturbance gradient in an eastern Australia semi-arid woodland.

Results: Vegetation, landform, and grazing disturbance affected litter and soil C and N pools singly and through interactions. Resource pools were distributed unevenly across vegetation and landforms, and were largest beneath trees in swales. Grazing reduced pools in vegetation-landform combinations where pools were greatest. Pool increases from high to moderate disturbance sites were minimal.

Conclusions: Litter and soil C and N pools are strongly affected by livestock grazing, although responses to grazing relaxation may be non-linear. Accurately predicting C and N responses to grazing in drylands will require accounting for patch differences at multiple spatial scales.

}, keywords = {Australia, carbon, grazing-induced disturbance, litter, nitrogen, nutrient pools, patch heterogeneity, soil organic carbon, spatial scale}, doi = {10.1007/s11104-012-1288-2}, url = {/files/bibliography/12-040.pdf}, author = {Smith, Jane G. and D.J. Eldridge and Heather L. Throop} } @inbook {49929, title = {Landscape approaches to rangeland conservation practices}, booktitle = {Conservation Benefits of Rangeland Practices: Assessment, Recommendations, and Knowledge Gaps}, year = {2011}, pages = {337-370}, publisher = {Allen Press}, organization = {Allen Press}, chapter = {8}, address = {Lawrence, KS}, abstract = {Our review indicates that landscape perspectives are needed to ensure the long-term success conservation practices in rangelands. We recommend that conservation practitioners consider several scales of spatial pattern and related spatial processes, including cumulative effects, each time a practice is applied. A large body of literature supports the utility of a landscape perspective. The core concepts include spatial heterogeneity, spatial pattern, and spatial scaling. Spatial heterogeneity is used to understand why a practice succeeds or fails in different areas. Spatial heterogeneity can also be a primary goal of practices. Spatial patterns are used to indicate critical processes that are not reflected in other measures, such as connectivity for wildlife movement or runoff and erosion potential. Patterns too can be a conservation objective. Spatial scaling is used to understand the dimensions of the land area over which spatial interactions link practices in one place to effects in other places, and conversely, how characteristics of the landscape affect the local success of a practice. The concepts are increasingly being connected to practical tools that can be used by planners. The tools can be used both to help design practices and to design the monitoring programs that evaluate their effects.\  A spatial hierarchy focuses attention on the data needed at each spatial scale governing ecological processes of interest. In order of decreasing scale, major land resource areas, soil geomorphic systems, watersheds, ecological sites, states or plant communities, and patches each relate to processes governing the management of rangelands. Furthermore, consideration of societal information such as land ownership is usually needed at broad scales. Each of these data sources can be consulted in a systematic way, which we described in nine steps, to design and evaluate practices in a landscape. While some of the tools are already used by conservation planners, the development of others will require a scientific and institutional investment by the federal government and support by universities and other science providers. Spatial data information systems should be developed that link maps, models, and pattern-based metrics to support planning and monitoring design. Databases are needed to house the resulting data alongside information on their landscape context. The interpretations of these data should be linked to ESDs. Foremost, we must invest in training and research to instill an understanding of the concepts and a capacity for reasoning about landscape processes. We suspect that such investments would pay for themselves, and then some, by improving conservation effectiveness in the millions of acres of rangelands that will be treated in years to come.}, keywords = {book, chapter, conservation practices, landscape approaches, rangeland, report}, isbn = {978-0-9849499-0-8}, url = {/files/bibliography/11-035.pdf}, author = {Brandon T Bestelmeyer and Wu, X.B. and Joel R. Brown and S. Fuhlendorf and G. Fults}, editor = {D.D. Briske} } @mastersthesis {49948, title = {Land cover classification and change detection in drylands: an evaluation of remote sensing approaches}, volume = {Master of Applied Geography}, year = {2011}, pages = {156}, school = {New Mexico State University}, address = {Las Cruces}, abstract = {Land cover change is occurring at unprecedented rates worldwide and is believed to contribute to environmental concerns such as altered biogeochemical cycles, loss of wildlife habitat, decreases in biodiversity, and reduction of soil productivity. Of particular concern are dryland regions of the world because they are experiencing rapid population growth which is a driver of land cover change. The Southwestern United States is one dryland region which is experiencing rapid population growth and associated expansion of urban land cover. The Mesilla Valley of Southern New Mexico is no exception. In this region, which has experienced rapid growth during the last four decades, it is unclear at what rate land cover is changing and what effects this has had on desert ecosystems. Satellite remote sensing can be of great value for mapping land cover and assessing land cover change. However, accurate land cover mapping of arid and semi-arid environments is challenging due to the natural characteristics of these environments. Few researchers have systematically investigated which combinations of image bands, image derivatives, and hard classification algorithms address the difficulties of mapping land cover in arid environments. This is important because hard classifications are by far the most commonly used technique for mapping land cover and drylands are particularly vulnerable to land cover change due to human population pressures. This study examined a series of hard classification techniques and image feature stacks in order to determine which combinations may provide accurate land cover maps in the Mesilla Valley of New Mexico. The tests were repeated for a second dryland region (Yuma Valley, Arizona) to see if they were generalizable to another dryland region. The feature combination that gave the highest accuracy was used to provide land cover information and land cover change maps of the Mesilla Valley, New Mexico between 1985 and 2009.}, keywords = {drylands, land cover change, land cover classification, Mesilla Valley, remote sensing, technique, Yuma Valley}, author = {Hestir, Kristen Lee} } @article {49971, title = {Long-term research across sites, ecosystems, and disciplines: synthesis and research needs}, year = {2011}, keywords = {cross-site research, long-term research, synthesis}, author = {Debra C. Peters} } @article {49974, title = {Long-term trends in climate and climate-related drivers}, year = {2011}, keywords = {climate drivers, climate-related drivers, long-term trends}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J.M. and A. K. Knapp and T. K. Kratz and Mark D. Ohman and R. B. Waide and Jin Yao} } @article {49973, title = {Long-term trends in precipitation and surface water chemistry}, year = {2011}, keywords = {ecological systems, global change, long-term trends, precipitation, surface water chemistry}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J.M. and A. K. Knapp and T. K. Kratz and Mark D. Ohman and R. B. Waide and Jin Yao} } @article {49970, title = {Long-term trends in production, abundance, and richness of plants and animals}, year = {2011}, abstract = {

Trends in biotic structure have been of interest in the United States since the establishment of the Division of Biological Survey in the U.S. Department of Agriculture in the late 1890s. Changes in iotic structure can serve as a bellwether for quantifying the effects of climate change, land-use change, and the spread of exotic species, as well as the loss of rare and endangered species. Considerable evidence suggests that changes in biotic structure can have significant consequences for ecosystem functioning and the provisioning of ecosystems goods and services. In this chapter, we first describe common methods for measuring responses of plants and animals and our rationale for the selection of variables included in this book. We then show graphs of biotic data through time for each site arrayed across the continent.

}, keywords = {animal abundance, animal production, animal species richness, ecological systems, global change, long-term trends, plant abundance, plant production, plant species richness}, url = {files/bibliography/JRN00577.pdf}, author = {Debra C. Peters and C. Laney and Ariel E. Lugo and S.L. Collins and Charles T. Driscoll and Peter M. Groffman and Grove, J.M. and A. K. Knapp and T. K. Kratz and Mark D. Ohman and R. B. Waide and Jin Yao} } @article {50007, title = {Land fragmentation under rapid urbanization: A cross-site analysis of Southwestern cities}, journal = {Uurban Ecosystems}, volume = {14}, year = {2011}, pages = {429-455}, abstract = {

Explosive population growth and increasing demand for rural homes and lifestyles fueled exurbanization and urbanization in the western USA over the past decades. Using National Land Cover Data we analyzed land fragmentation trends from 1992 to 2001 in five southwestern cities associated with Long Term Ecological Research (LTER) sites. We observed two general fragmentation trends: expansion of the urbanized area leading to fragmentation in the exurban and peri-urban regions and decreased fragmentation associated with infill in the previously developed urban areas. We identified three fragmentation patterns, riparian, polycentric, and monocentric, that reflect the recent western experience with growth and urbanization. From the literature and local expert opinion, we identified five relevant drivers {\textendash} water provisioning, population dynamics, transportation, topography, and institutions {\textendash} that shape land use decision-making and fragmentation in the southwest. In order to assess the relative importance of each driver on urbanization, we linked historical site-specific driver information obtained through literature reviews and archival analyses to the observed fragmentation patterns. Our work highlights the importance of understanding land use decision-making drivers in concert and throughout time, as historic decisions leave legacies on landscapes that continue to affect land form and function, a process often forgotten in a region and era of blinding change.

}, keywords = {drivers, exurbanization, institutions, land fragmentation, land use, population dynamics, topography, transportation, urban ecology, US Southwest, water provisioning}, doi = {10.1007/s11252-011-0157-8}, url = {files/bibliography/JRN00571.pdf}, author = {York, Abigail M. and Shrestha, Milan and Boone, Christopher G. and Zhang, Sainan} } @mastersthesis {50008, title = { Land-use decision-making and landscape degradation: a case study in the American Southwest }, volume = {Doctor of Philosophy}, year = {2011}, month = {June 2011}, pages = {277}, school = {The University of Sheffield}, type = {Dissertation}, address = {Sheffield, UK}, abstract = {This study examines the role of land-use decision-making of different actor groups, including land developers, politicians, residents, NGOs and city planners, in contributing to land degradation in the American Southwest. Perceptions of different actor groups of the desert landscape are first explored then the motivations and priorities of actor groups to make land-use decisions are investigated. It was found that perceptions of landscape are connected with its functional and intrinsic values. Different groups appreciated functional values with their specific needs and interests. Also, an appreciation of intrinsic values of landscape is partly associated with functional values. By taking a political ecology approach, this study investigates the complex relationships between human land-use decisions and environmental changes and between different actor groups. Issues of power were found to be significant in land use and management practice, and a small number of actors were perceived by others to have more power to control the use and access to the resources. Relationships between and within different actor groups are complex, and conflict when special interests and needs of actors are apparent with some actors considering their rights and power to be limited and diminished by others. Decisions made at local scale are often affected by the regulations and policies operating at regional and national scales. Results also revealed that historical and cultural influences played a role in the decision-making process. In addition, it was found that poor communications exist between actor groups and between different levels of government, and misunderstanding and lack of negotiation between each other can result in conflicts and competition. Land managers and planners need to incorporate opinions and expectations from a wider public and balance the complex diversity of needs of different actor groups.}, keywords = {American Southwest, land degradation, land use, urban development, wildland-urban interface}, author = {Yu, Yang} } @proceedings {50015, title = {Local and global patterns of shrub proliferation - changes in autocorrelation in an arid rangeland ecosystem from 1937-2008.}, year = {2010}, month = {June 25-30, 2010}, abstract = {The proliferation of trees and shrubs in grassland and savanna ecosystems has been widely observed, although future trajectories remain difficult to ascertain. Spatial manifestations of shrub proliferation bear relevance on surface hydrology and the spread of disturbance. We quantify changes in spatial autocorrelation in shrub cover in an arid grassland ecosystem to test the validity of a conceptual framework highlighting the role of shrub patch dynamics in the shrub encroachment process. We build upon the framework to suggest how the encroachment and stabilization phases manifest spatially. We suggest that indicators of spatial autocorrelation illustrate where local interactions are more prevalent, thereby functioning as an indicator of biotic regulation and stabilization in shrub cover. We analyzed binary maps of shrub cover from 1937 to 2008 derived from time series aerial photography. Spatial analyses entailed resampling 1-m depictions of shrub patches to percent shrub cover within 20-m X 20-m quadrats to examine the spatial autocorrelation with Moran{\textquoteright}s I using GeoDa software. We decomposed the global index of spatial association into contributions from local neighborhoods using Local Indicator of Spatial Association, which quantifies the extent to which cells are similar to or different from their neighbors. Shrub cover in 1937 was highly heterogenous and became more dispersed and less patchy over the 71 years. As shrub cover increased, it became increasingly positively autocorrelated with Moran{\textquoteright}s I increasing from 0.383 in 1937 to 0.742 in 2008. We found no clear evidence of self-organization, although we did detect clear evidence of local effects that resulted in broad scale patterns with hot-spots of low and high cover. The trend highlights the potential for edaphic or geomorphic constraints on shrub cover. We anticipate collecting field data on vegetation structure, cover, and soil properties to discern whether segregated patterns in autocorrelation are related to land surface conditions.}, author = {Dawn M. Browning and Andrea S. Laliberte and A. Rango} } @article {50028, title = {Learning natural resource assessment protocols: Elements for success of lessons from an international workshop in Inner Mongolia, China}, journal = {Rangelands}, volume = {32}, year = {2010}, pages = {2-9}, abstract = {

Learning to complete natural resource assessments requires hands-on training. This paper illustrates eight elements of successful international workshops illustrated by data and experiences from a workshop in Inner Mongolia, China: translation, integration of a site potential-based land classification system, integration of quantitative data, participant diversity, participant commitment to training, discussion of applications, connection to decision makers, and proximity of field and classroom locations. Success in transferring knowledge is seen via consistent, positive courseevaluations by participants, but ultimate success of these types of workshops will be reflected in theparticipants use of the information in future decision making.

}, url = {/files/bibliography/10-015.pdf}, author = {G. Han and Jeffrey E. Herrick and Brandon T Bestelmeyer and D.A. Pyke and P. L. Shaver and Hong, M. and M. Pellant and F. Busby and Kris Havstad} } @proceedings {JRN54489, title = {Land health and ecological sites: application to land use planning and management}, year = {2010}, month = {10/2010}, pages = {48-57}, publisher = {First International Rangeland Congress Chiapas.}, address = {Chipas, Mexico}, abstract = {

Land health is a powerful tool for land use planning and management of croplands, forests, and rangelands. It is difficult, expensive and often impossible to assess and monitor the status of land relative to its potential to support each of these ecosystem services. However, there are three attributes of the land that reflect its capacity to support all of these services. These attributes include: Soil and Site Stability, Hydrologic Function, and Biotic Integrity. Applying the land health concept to land use planning begins with defining the land\&$\#$39;s potential using a land classification system (Step 1), assessing the land (Step 2), developing the plan (Step 3), developing early warning systems (Step 4), and adapting land use, often at different temporal scales (Step 5). Land use planning and management based on land health and ecological sites can improve the usefulness of land use planning. This approach requires farmers and technical specialists to work together to determine the land\&$\#$39;s potential and its current status relative to potential.

}, url = {files/bibliography/10-054.pdf}, author = {Jeffrey E. Herrick and Brandon T Bestelmeyer and Joel R. Brown and Jason W. Karl} } @conference {50096, title = {Linking biological conservation to healthy rural communities: a case history of the Janos {\textendash} Casas Grandes Biosphere Reserve}, booktitle = {Ecological Society of America}, year = {2009}, note = {Abstract $\#$ 20230}, month = {08/2009}, pages = {COS 103-6}, address = {Albuquerque, NM}, abstract = {

During the late 1930\’s, Aldo Leopold witnessed a striking contrast along the narrow boundary between the United States and Mexico. He later described Mexican ecosystems as a \“lovely picture of ecological health\” and those same ecosystems north of the U.S. - Mexico border as \“so badly damaged that only tourists and those ecologically blind, can look upon them without a feeling of sadness, and regret.\” On this the hundredth centennial of Leopold\’s arrival in the Southwest, the difference has waned but has not completely vanished. Within Mexico\’s Janos \– Casas Grande region lays the largest black-tailed prairie dog complex within North America, reminiscent of past ecosystems just north of the border. Now a Biosphere Reserve, collaborative efforts between Mexican and U. S. scientists are reconstructing the area\’s ecological history and identifying key ecosystem properties maintaining grasslands and essential ecosystem services.

}, keywords = {abstract, biological conservation, Casa Grandes Biosphere Reserve, ESA, Janos}, author = {E.L. Fredrickson and G. Ceballos and List, R. and Barajas, N. and N. F. Sayre and Roacho, E.J.O. and Sierra, C.R. and G.E. Ponce and A.D. Davidson and Melgoza, A. and Jaquez, C. and G. Bezanilla} } @conference {50104, title = {Land use planning and early warning systems for limiting drought impacts and promoting recovery}, booktitle = {ESA meeting}, year = {2009}, publisher = {Ecological Society of America}, organization = {Ecological Society of America}, address = {Albuquerque, NM}, abstract = {Land use planning and drought early warning systems both require an understanding of ecological potential and resilience, and how they vary across space and through time. A large body of literature and local knowledge has documented the importance of considering soil variability for land use planning, including how to plan for and respond to drought. A number of tools are now available and are being developed to assist with this process, including the Global Soil Map.}, keywords = {Global Soil Map, ipm}, author = {Jeffrey E. Herrick} } @conference {50103, title = {Landscape variability in response to changes in patch-scale connectivity}, booktitle = {Ecological Society of America Abstracts}, year = {2009}, month = {2009}, chapter = {PS 46-49}, abstract = {Extensive redistribution of water, organic matter and nutrients occurs in many arid and semi-arid ecosystems due to high spatial connectivity and the strength of wind and water vectors. The {\textquoteleft}leakiness{\textquoteright} of these systems has been cited as an indicator of degradation. Attempts to limit or modify soil loss and redistribution is a component of many restoration strategies. There are surprisingly few data, however, about the extent to which reducing connectivity at the plot level results in increased resource retention or plant establishment, or how these effects might vary across the landscape. The objective of this study was to determine the extent to which reducing connectivity in plant interspaces can increase resource retention and plant establishment at plant and patch scales in three contrasting sites. Two sites are located on gravelly soils are dominated by alluvial processes. One of these is on a geomorphically stable and the other on a geomorphically unstable surface. The third site is located on a sandy soil and is believed to be dominated by aeolian processes. Four paired treatment and control plots were established in late spring {\textendash} early summer 2008 and evaluated in fall 2008 with digital photographs. The results showed significant reductions in bare ground at all three sites that were associated with increases in litter cover. The reductions were much greater at the aeolian site (26\%) and the alluvial site on an geomorphically unstable surface (22\%) than on at the geomorphically stable, lower productivity site (3\%). These preliminary results illustrate the importance of testing hypotheses about the importance of connectivity across a broad variety of plant communities and geomorphic surfaces.}, author = {Jeffrey E. Herrick and Debra C. Peters and Gregory S. Okin and John P. Anderson} } @conference {50161, title = {Landscape variability in soil and vegetation response to 70-year-old restoration treatments}, booktitle = {93rd Ecological Society of America Annual Meetings}, year = {2008}, month = {August 4-8, 2008}, pages = {67-159}, address = {Milwaukee, WI}, abstract = {During the 1930{\textquoteright}s the Civilian Conservation Corps implemented a number of landscape restoration projects, most of which were abandoned in the early 1940{\textquoteright}s. Although many restoration projects failed, several projects had a lasting effect on the landscape and can be used to study the long term effects of restoration treatments. Restoration treatments including soil berms were created in Las Cruces, New Mexico in the early 1930{\textquoteright}s. Soil berms are soil barriers laid across the contours of the landscape to slow water movement resulting in water ponding and increased water infiltration. Water ponding initiates a cyclical feedback system where the establishment of vegetation (grasses) promotes soil stability and soil stability increases vegetation establishment. Soil berms mimic naturally banded vegetation. The objective of this project was to assess landscape variability in soil and vegetation response to soil berms in order to guide future restoration efforts in the Chihuahuan Desert, and better understand the ecological processes associated with soil and vegetation recovery. GIS analysis was carried out using a 1936 to 2005 chronosequence of aerial photographs. Ground measurements were completed to supplement the 2005 GIS analysis.}, keywords = {CCC, Civilian Conservation Corps, restoration}, author = {Noemi Baquera and Jeffrey E. Herrick and Curtis H. Monger and A. Rango and Heather L. Throop and Danielle Duni} } @article {50183, title = {Large area mapping of southwestern forest crown cover, canopy height, and biomass using the NASA Multiangle Imaging Spectro-Radiometer}, journal = {Remote Sensing of Environment}, volume = {112}, year = {2008}, month = {April 1, 2008}, pages = {2051-2063}, abstract = {

A rapid canopy reflectance model inversion experiment was performed using multiangle reflectance data from the NASA Multi-angle Imaging Spectro-Radiometer (MISR) on the Earth Observing System Terra satellite, with the goal of obtaining measures of forest fractional crown cover, mean canopy height, and biomass for parts of S.E. Arizona and S. New Mexico (\>200,000 km2). MISR red band bidirectional reflectance estimates in nine views mapped to a 250 m grid were used to adjust the Simple Geometric-optical Model (SGM). The soil-understory background signal was decoupled a priori by developing regression relationships with the nadir camera blue, green, and near-infrared reflectance data and the isotropic, geometric, and volume scattering kernel weights of the LiSparse-RossThin kernel-driven bidirectional reflectance distribution function (BRDF) model, adjusted against MISR red band data. The SGM{\textquoteright}s mean crown radius and crown shape parameters were adjusted using the Praxis optimization algorithm, allowing retrieval of fractional crown cover, mean canopy height and their dot product, a coarse surrogate for biomass. Retrieved distributions these parameters for forested areas showed good matches with maps from the United States Department of Agriculture (USDA) Forest Service, with R2 values of 0.76, 0.58 and 0.53, post-filtering for high root mean square error (RMSE) and cloud/cloud-shadow contamination. Some areas with important shrub cover are predicted to have low or no woody plant cover, indicating the need to adjust the background calibration and reflecting the difficulty of estimating canopy parameters in low cover environments. This is the first attempt to use data from MISR to produce maps of crown cover, canopy height, and biomass over a large area by seeking to exploit the structural effects of canopies reflected in the observed anisotropy patterns in these explicitly multiangle data.

}, keywords = {crown cover, forest, journal article, MISR, southwestern}, doi = {10.1016/j.rse.2007.07.024}, url = {/files/bibliography/08-007.pdf}, author = {M. Chopping and Moisen, G. and L. Su and Andrea S. Laliberte and A. Rango and J. V. Martonchik and Debra C. Peters} } @conference {50207, title = {Landscape histories, livestock management, and mesquite expansion in the Chihuahuan Desert of New Mexico}, booktitle = {Society for Range Management Annual Meeting}, year = {2008}, month = {January 26, 2008}, pages = {2188}, address = {Louisville, KY}, abstract = {During the past 125 years the northern Chihuahuan Desert has undergone a significant shift from desert grasslands to desert shrub conditions, with mesquite (Prosopis glandulosa) dramatically increasing in dominance during this period. The transition from desert grasslands is viewed as deleterious, decreasing forage availability for both wildlife and livestock while negatively impacting air, water, and soil processes that support ecosystem services important to rapidly growing, human populations. Causes leading to this transition include formulation of government and industry policies, and later application of some range management principles, without an understanding of the evolutionary and landscape history of the northern Chihuahuan Desert. In addition, as causes of mesquite expansion were determined, primary factors leading to mesquite{\textquoteright}s eventual dominance did not receive adequate attention, most likely because they did not fit within dominant scientific paradigms, or social-political realities of the time. Future work needs to focus on better understanding evolutionary and landscape legacies of this region; including factors that created and maintained the original desert grasslands prior to desert scrub conditions. Using this understanding we must create appropriate theory that will guide future human-ecological interactions and assessment of ecological trajectories. This knowledge must affect policy and eventual management. We must relax the need for ecosystems to adapt to human behaviors and consider how human behaviors can best adapt to the ecosystems on which they depend.}, keywords = {Chihuahuan Desert}, author = {E.L. Fredrickson and Jeffrey E. Herrick and H. Raul Peinetti and Andrea S. Laliberte} } @conference {50209, title = {Line-point intercept, grid-point intercept,and ocular estimate methods: their relative value for rangeland assessment and monitoring}, booktitle = {Society for Range Management Annual Meeting}, series = {Building Bridges: Grasslands to Rangelands}, year = {2008}, month = {January 26-31, 2}, pages = {2380}, address = {Louisville, KY}, abstract = {We compared the utility of three methods for rangeland assessment and monitoring based on the number of species detected, foliar cover, precision (coefficient of variation) and time required for each method. We used four 70-m transects in 15 sites of five vegetation types (3 sites/type). Point intercepts were recorded every 1 m along each transect (280 points/site). Five one square meter quadrats (for ocular and grid-point) were located on each transect (20 quadrats/site). Grid-point intercepts were recorded in 16 points evenly distributed in each quadrat (320 points/site). Foliar cover estimates based on line-point and grid-point intercept methods were similar and correlated based on Spearman{\textquoteright}s correlations (r =0.96, p<0.0001). Ocular estimates were poorly correlated with other methods, although they were significant (Line-point: r =0.62, p=0.007; Grid-point: r =0.70, p=0.002). The relationship between foliar cover estimated with line-point and ocular estimates varied with vegetation type. The number of species detected per site by line-point (17 {\textpm} 2) and grid-point (16 {\textpm} 2) intercept methods was significantly lower than the number detected by ocular estimates (21 {\textpm} 2). The time required for line-point (23 {\textpm} 2 min) was less than for grid-point intercept (31 {\textpm} 3) and ocular estimates (27 {\textpm} 4). The coefficient of variation (n=15 sites) was lower for the line point (32\%) than for grid-point (37\%) or ocular (49\%). This study supports others indicating that ocular estimates are more effective for detecting species, while line-point intercept and gridpoint provide more precise cover estimates. These results suggest that when assessing the effects of conservation practices (e.g. CEAP), methods should be selected based on objectives (e.g. biodiversity vs. cover). The results also suggest that species area curves can be used to estimate total species using any of the methods. Future analyses will include comparisons with ground and aerial photography.}, keywords = {grid-point, line-point, monitoring, ocular, rangeland assessment}, author = {Godinez-Alvarez, H. and Jeffrey E. Herrick and M. Mattocks and David P. Toledo and Justin Van Zee} } @article {50224, title = {A lunch date with your future: Exploring non-academic jobs through personal interviews}, journal = {Frontiers in Ecology and the Environment}, number = {6}, year = {2008}, note = {review article}, month = {06/2008}, pages = {337-338}, type = {Article response}, abstract = {

This article is a response to an article by Eileen Thorsos in which she describes how non-academic jobs can be explored through personal interviews. The response emphasizes the importance of finding people, rather than job titles, to interview. The same title can mean very different things in different organizations, and even within the same organization. Soil scientists who work for the Natural Resources Conservation Service may be asked to spend much of their time conducting workshops and developing protocols, while US Forest Service, US Department of Agriculture Agricultural Research Service (ARS), and US Geological Survey scientists often have responsibilities that are virtually distinguishable from those of university professors with 100\% research appointments. Although Thorsos\’ structured approach has several potential benefits, more serendipitous conversations can be equally valuable when searching for subjects, keep in mind that the most obvious venues are not necessarily the best. The article concludes by encouraging other students to follow Thorsos\’ lead, while keeping in mind that many of the same limitations that apply to ecological research based on small, non-random samples also apply to career investigations.

}, keywords = {article, interviews, non-academic, review article, Thorso}, url = {/files/bibliography/08-057.pdf}, author = {Jeffrey E. Herrick} } @article {50229, title = {Landscape position moderates how ant nests affect hydrology and soil chemistry across a Chihuahuan Desert watershed}, journal = {Landscape Ecology}, volume = {23}, year = {2008}, month = {11/2008}, pages = {961-975}, chapter = {961}, abstract = {

Ants moderate the supply of critical resources such as water and nutrients in desert environments by changing the physical arrangement of soils during nest construction. We measured water infiltration and soil physical and chemical properties on and off the nests of two ant species (Pogonomyrmex rugosus, Aphaenogaster cockerelli) across five sites at differing landscape positions within a Chihuahuan Desert watershed. Our aim was to test whether the effects of these long-lived ant nests on water infiltration and soil chemistry varied between ant species or across sites within a watershed. Water flow was generally slowest at the site with the highest silt and clay contents, and fastest at the site with sandy soils. Flow was generally greater through ant nest soils than adjacent non-nest soils, and we attribute this to increases in macropores in the nests. However, the effects of both ant nests and species varied among sites. Despite wide variation in soil chemical properties across all sites, ant nests had a consistent effect on soil chemical properties, with higher levels of carbon, nitrogen, sulphur, phosphorus and electrical conductivity on nests compared with non-nest soils. Our results demonstrate that while we can generalise about the effects of ant nests on water flow and nutrient levels, differences in soil type, nest density and ant species across sites are likely to moderate these effects.

}, keywords = {infiltration, Landscape scale, macropores, soil nutrients, Sorptivity}, doi = {10.1007/s10980-008-9251-6}, url = {/files/bibliography/08-039.pdf}, author = {Angela James and Edridge, D.J. and T. B. Koen and Walter G. Whitford} } @article {50245, title = {Long-term data collection at USDA experimental sites for studies of ecohydrology}, journal = {Ecohydrology}, volume = {1}, year = {2008}, month = {2008}, pages = {377-393}, abstract = {

Federally established watersheds, rangelands and forests have produced long-term records of biotic and abiotic measurements that span decades and centuries across the U.S. The goal of this review is to express the value of such long-term data for understanding and predicting ecosystem dynamics and the importance of continued long-term data collection. The basic conclusion is that the current understanding of hydrologic, ecologic, and climatic processes would simply not be possible without these multi-decadal datasets. Similarly, the development of many prediction models has been based largely on parameterization and validation with these data. As a result, long-term data have influenced management strategies for the most important activities and events affecting our natural resources, including livestock grazing, erosion control, logging, urbanization, disease, flood, drought, fire, desertification, and non-native plant invasion. Long-term data collection is just as important now as it was when the federal experimental watersheds, rangelands and forests were established nearly a century ago. There is a movement in the U.S. to develop a network of networks to study spatial patterns as well as temporal trends. Toward this integrated scientific infrastructure, new long-term data collection efforts have been designed to coordinate with existing networks, and existing long-term data collection networks have adapted their measurements to address new science issues. This flexibility and foresight has made, and continues to make, long-term data collection sustainable, relevant and inherently valuable.

}, keywords = {abiotic, biotic, long-term, watersheds}, doi = {10.1002/eco.24}, url = {/files/bibliography/08-040.pdf}, author = {S. Moran and Debra C. Peters and M.P. McClaran and M. H. Nichols and M.B. Adams} } @conference {50246, title = {Long-term data collection at USDA experimental sites for studies of ecohydrology}, booktitle = {28th Conference on Agriculture and Forest Meteorology}, year = {2008}, month = {April 28, 2008}, abstract = {The goal of this review is to show the value of long-term, continuous data from the network of USDA experimental watersheds, forests and ranges for studying the interaction between ecology and hydrology, termed ecohydrology. We identified 81 USDA experimental sites with data records of more than 20 years measuring important ecosystem dynamics, such as variations in vegetation, precipitation, climate, runoff, water quality and soil moisture. Through a series of examples, we showed how USDA long-term data have been used to understand key ecohydrological issues, including 1) critical thresholds and cyclic trends, 2) time lags between cause and effects, 3) context of rare and extreme events and 4) land surface simulation modeling. New analyses of network-wide, long-term data from USDA experimental sites were used to explore the scales of temporal and spatial measurement required for ecological and hydrological research. The results underscored the need for continuous, interdisciplinary data records spanning more than 20 years across a wide range of ecosystems within and outside the conterminous U.S. for key ecohydrological research. The basic conclusion is that USDA experimental sites play a unique and important role in addressing the major crosscutting problems facing ecohydrology, such as spatial complexity and scaling, thresholds, and feedbacks and interactions. Conversely, the heightened interest in ecohydrology has impacted USDA experimental sites by encouraging new long-term data collection efforts and adapting existing long-term data collection networks to address new science issues.}, keywords = {abstract, ecohydrology, ecology, hydrology, long-term, watersheds}, author = {S. Moran and Debra C. Peters and M.P. McClaran and M. H. Nichols and M.B. Adams} } @article {50254, title = {Living in an increasingly connected world: a framework for continental-scale environmental science}, journal = {Frontiers in Ecology and the Environment}, volume = {6}, number = {5}, year = {2008}, month = {June 2008}, pages = {229-237}, abstract = {

The global environment is changing rapidly through processes that act at multiple spatial and temporal scales. It is now clear that local processes can affect broader-scale ecological dynamics, and that broad-scale drivers may at times overwhelm local patterns and processes. Understanding these cross-scale interactions requires a conceptual framework to predict continental-scale ecosystem dynamics based on connectivity in material and information flow across scales. In this paper, we (1) discuss a multi-scale conceptual framework, including the key drivers and consequences of ecological connectivity acting across spatial and temporal scales, (2) provide a series of testable hypotheses, predictions, and an approach derived from this conceptual framework, and (3) propose the development of a network of networks largely taking advantage of existing research facilities and cyberinfrastructure to address these hypotheses. This framework and associated research infrastructure based on connectivity across scales will uniquely enable our understanding and enable us to better forecast global environmental change at multiple spatial scales, from local research sites to regions and continents.

}, keywords = {article, continental-scale, environment, journal, spatial, temporal}, doi = {10.1890/070098}, url = {/files/bibliography/08-011.pdf}, author = {Debra C. Peters and Peter M. Groffman and K.J. Nadelhoffer and N.B. Grimm and S.L. Collins and Michener, W.K. and Huston, M.A.} } @inbook {50278, title = {Land resources: forests and arid lands}, booktitle = {The effects of climate change on agriculture, land resources, water resources, and biodiversity in the United States.}, series = {Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research}, number = {Synthesis and Assessment Product 4.3.}, year = {2008}, note = {//USDA//LTER V//entered 05/29/2008; PDF availableProCite field[6]: InProCite field[8]: Convening lead authorsProCite field[31]: Managing editor}, month = {2008}, pages = {362 pp.}, address = {Washington, DC., USA}, abstract = {

This synthesis and assessment report builds on an extensive scientific literature and series of recent assessments of the historical and potential impacts of climate change and climate variability on managed and unmanaged ecosystems and their constituent biota and processes. It identifies changes in resource conditions that are now being observed and examines whether these changes can be attributed in whole or part to climate change. It also highlights changes in resource conditions that recent scientific studies suggest are most likely to occur in response to climate change, and when and where to look for these changes. As outlined in the Climate Change Science Program (CCSP) Synthesis and Assessment Product 4.3 (SAP 4.3) prospectus, this chapter will specifically address climate-related issues in forests and arid lands.In this chapter the focus is on the near-term future. In some cases, key results are reported out to 100 years to provide a larger context but the emphasis is on next 25-50 years. This nearer-term focus is chosen for two reasons. First, for many natural resources, planning and management activities already address these time scales through development of long-lived infrastructure, forest rotations, and other significant investments. Second, climate projections are relatively certain over the next few decades. Emission scenarios for the next few decades do not diverge from each other significantly because of the {\textquotedblleft}inertia{\textquotedblright} of the energy system. Most projections of greenhouse gas emissions assume that it will take decades to make major changes in the energy infrastructure, and only begin to diverge rapidly after several decades have passed (30-50 years).

}, keywords = {arid lands, book, chapter, climate change, desertification, report}, url = {files/bibliography/JRN00504.pdf}, author = {Ryan, M. G. and Steven R. Archer and Birdsey, R. and Dahm, C. and Heath, L. and Hicke, J. and Hollinger, D. and T. Huxman and Gregory S. Okin and Oren, R. and J. Randerson and W. H. Schlesinger}, editor = {Backlund, Peter and Janetos, Anthony and David Schimel} } @conference {50307, title = {Linking ground observations, simulation model output, and remote sensing data to characterize phenology across diverse arid landscapes}, booktitle = {American Society of Photogrammetry and Remote Sensing Meetings}, series = {Southwest Region}, year = {2007}, month = {October 5, 2007}, abstract = {We combined long-term data on plant phenology with simulation modeling output and remote sensing data to characterize diverse landscapes at the Jornada Experimental Range in the northern Chihuahuan Desert of southern New Mexico. Phenology of 15 key species in Chihuahuan Desert plant communities have been monitored monthly for 15 sites since 1992. Phenological state (non-reproductive, in bud, in flower, dormant) is noted for all plants of selected grass and shrub species at three replicate sites of five major plant communities (upland grasslands, playa grasslands, creosotebush shrublands, mesquite shrublands, tarbush shrublands). We combined these long-term data with simulation model results of key species to extrapolate back in time and to forecast future dynamics under a changing climate. We used a daily timestep model of soil water dynamics (SOILWAT) to simulate recruitment of the dominant grass for the entire Jornada Basin. We also compared the long-term data with remotely sensed images through time for one year from the ASTER satellite. The ability of the ASTER images to sense phonological changes varied by community type. Linking different technologies has great potential for improving understanding and prediction for arid landscapes that vary both temporally and spatially.}, keywords = {Chihuahuan Desert, phenology, remote sensing, simulation}, author = {John P. Anderson and Debra C. Peters and A. Rango and Caitriana Steele} } @article {50413, title = {Linking the Concept of Scale to Studies of Biological Diversity: Evolving Approaches and Tools}, journal = {Diversity and Distributions}, volume = {12}, year = {2006}, note = {//NONE//LTER IV//Entered 06/09/2006}, month = {2006}, pages = {229-235}, abstract = {

Although the concepts of scale and biological diversity independently have received rapidly increasing attention in the scientific literature since the 1980s, the rate at which the two concepts have been investigated jointly has grown much more slowly. We find that scale considerations have been incorporated explicitly into six broad areas of investigation related to biological diversity: (1) heterogeneity within and among ecosystems, (2) disturbance ecology, (3) conservation and restoration, (4) invasion biology, (5) importance of temporal scale for understanding processes, and (6) species responses to environmental heterogeneity. In addition to placing the papers of this Special Feature within the context of brief summaries of the expanding literature on these six topics, we provide an overview of tools useful for integrating scale considerations into studies of biological diversity. Such tools include hierarchical and structuralequation modelling, kriging, variable-width buffers, k-fold cross-validation, and cascading graph diagrams, among others. Finally, we address some of the major challenges and research frontiers that remain, and conclude with a look to the future.

}, keywords = {article, Biodiversity conservation, biological invasions, extent, future challenges, journal, modelling, publication chronology, resolution}, doi = {10.1111/j.1366-9516.2006.00260.x}, url = {/files/bibliography/06-022.pdf}, author = {E.A. Beever and Swihard, Robert K. and Brandon T Bestelmeyer} } @conference {50426, title = {Landscape variation in desert rodent community response to grass-shrubland ecotones}, booktitle = {21st Annual Symposiumof the United States Regional Chapter of the International Association of Landscape Ecology}, year = {2006}, month = {March 28-April 1}, pages = {Paper No. 11}, address = {San Diego, CA}, abstract = {Desert rodents exert strong effects on soil, vegetation, and other animals. It has been reported that the abundance and diversity of Chihuahuan Desert rodents increases with shrub encroachment accompanying desertification although grassland specialist species decline with loss of perennial grasses. The consistency of such patterns across a landscape, however, has not been examined. We tested the hypothesis that rodent richness, biomass, and density/abundance were highest in shrub-dominated portions of replicate grassland-shrubland ecotones. Five such ecotones were examined within the same vegetation types and soils (Bouteloua eriopoda and Prosopis glandulosa on coarse loamy Argids). The ecotones are dynamic (with shrubs expanding into grasslands over the last century) but varied in total shrub and grass abundance depending on mesoclimate and disturbance history. Rodents were trapped from 2002-2005 on grids of 96 traps located within each of three positions in each ecotone: grass-dominated, transitional, and shrub-dominated. We found that abundance/density and biomass exhibited inconsistent relationships to position within ecotones, but rodent abundance and sometimes richness and biomass were positively related to shrub cover across the entire landscape over the 3 periods. Species composition was highly variable among ecotones. Perennial grass cover and bare ground cover were not important. We conclude that relative differences in shrub cover within an ecotone are less important for aggregate measures of rodent communities than absolute differences in shrub cover across the landscape. The relationship of rodent composition to vegetation, however, is spatially and temporally variable.}, keywords = {abstract, abstracts, ecotones, grass-shrubland, rodent, shrub}, author = {A. Campanella and Brandon T Bestelmeyer and Debra C. Peters} } @proceedings {50546, title = {Livestock Research on the Jornada Experimental Range}, year = {2005}, month = {April 7-8, 2005}, pages = {100-102}, publisher = {NMSU College of Agriculture and Home Economics}, address = {Alamogordo, NM}, abstract = {The role of phytochemistry in diet selection by livestock on arid rangelands is being examined at the Jornada Experimental Range (JER) because shrub encroachment into arid and semiarid rangelands is a serious problem for livestock producers. Palatability of these shrubs is often low due to high concentrations of secondary chemicals. Our previous research has shown that crude extracts of tarbush (Flourensia cernua) applied to alfalfa pellets dramatically decreased intake by lambs. However, little is known about how specific compounds affect herbivory. Only 4 of the 19 terpenes we have examined reduced intake when tested individually (camphor, alpha-pinene, caryophyllene oxide, and camphene). Secondly, we are examining ways to control livestock in large pastures with fewer fences. Directional Virtual Fencing (DVF{\texttrademark}) is being tested as a mechanism to contain livestock and improve grazing distribution. This system uses ramped sound and electric shock administered on either side of an animal to keep it within a Virtual Paddock (VP{\texttrademark}) using minimum stress. With GPS data obtained from animals, we determined that cattle and sheep bonded to cattle (i.e., a flerd) could be controlled using DVF{\texttrademark}. A third study examines grazing behaviors of Mexican criollo cattle. Criollo cattle have coevolved with the arid and semiarid regions of North America for approximately 450 years and may have adaptations to arid environments that may be useful for livestock producers. We imported cattle from the Chinipas region of Chihuahua to the JER and compared distance traveled by these animals to Angus x Hereford cattle in a 3000-acre pasture with good forage conditions. Chinipas cattle traveled 7.9 {\textpm} 0.7 miles per day and covered a larger area of the pasture than Angus x Hereford cattle, which traveled 6.0 {\textpm} .4 miles. These data support observations that criollo cattle travel further and use steeper slopes than British or Continental breeds.}, keywords = {history, JER, Jornada Experimental Range, remediation}, url = {/files/bibliography/05-052Proc.pdf}, author = {Richard E. Estell and D.M. Anderson and E.L. Fredrickson} } @article {50567, title = {Loss of phenolic compounds from leaf litter of creosotebush [Larrea tridentata (Sess. \& Moc. ex DC.) Cov] and tarbush (Flourensia cernua DC.)}, journal = {Journal of Arid Environments}, volume = {61}, number = {1}, year = {2005}, month = {April 1, 2005}, pages = {79-91}, abstract = {We examined loss of organic matter and phenolics from leaf litter of two shrubs that are invasive in the Chihuahuan Desert. Fiberglass bags (1-mm mesh) containing creosotebush [The objective of this paper is to provide insights into exotic and native invasive species dynamics using a conceptual model developed from the long history of research on native woody plant invasion into perennial grasslands. We first describe our new conceptual model that focuses on landscape characteristics (spatial configuration and connectivity) interacting with environmental drivers and biotic processes across multiple scales. We then provide support for the model using a long-term dataset from southern New Mexico. Finally, we discuss new insights this model has to offer for understanding, predicting, and managing exotic invasive species dynamics. (Sess. \& Moc. ex DC.) Cov.] or tarbush (Flourensia cernua DC.) leaf litter were placed below shrubs in two positions (soil surface and 5 cm belowground) and removed at several intervals up to 90 days during winter (creosotebush and tarbush) and spring (creosotebush). Over the 90-day sampling interval, organic matter loss from creosotebush and tarbush during the winter sampling period was low for both surface and buried litter, ranging from 1.7-5.2\%. Losses of organic matter from creosotebush litter during the spring were much greater (75.1 and 33.5\% for buried and surface samples, respectively). Total phenolic losses after 90 days were 1.6, 4.8, 21.6, 13.5, 87.1, and 43.5\% for winter buried creosotebush, winter surface creosotebush, winter buried tarbush, winter surface tarbush, spring buried creosotebush, and spring surface creosotebush litter, respectively, while losses of condensed tannins for the same samples were 45.8, 56.1, -34.0, -41.8, 91.1, and 67.4\%. Nordihydroguaiaretic acid loss from creosotebush litter was 25.4, 18.3, 95.2, and 66.7\% for winter buried, winter surface, spring buried, and spring surface samples, respectively, over the 90-day interval. Losses of organic matter and phenolics were generally greater in buried vs. surface and spring vs. winter samples, and losses typically occurred during the last 30-45 days. http://www.sciencedirect.com/science?_ob=MImg\&_imagekey=B6WH9-4DGW3YW-3-C\&_cdi=6845\&_user=1496926\&_orig=browse\&_coverDate=04\%2F01\%2F2005\&_sk=999389998\&view=c\&wchp=dGLbVlb-zSkzV\&md5=f5a61c1ff74b379cac3f662abc4550b3\&ie=/sdarticle.pdf}, keywords = {creosotebush, Flourensia cernua DC., Larrea tridentata, leaf litter, loss, organic matter, phenolics, tarbush}, url = {/files/bibliography/05-024.pdf}, author = {P.W. Hyder and E.L. Fredrickson and Richard E. Estell and M.E. Lucero and M.D. Remmenga} } @proceedings {50577, title = {Low-stress weaning and preconditioning considerations}, year = {2005}, month = {April 7, 2005}, pages = {56-60}, address = {Alamogordo, New Mexico}, abstract = {There are several sources of stress that can impact cattle throughout their lives. Sources of stress, like branding, weaning, shipping, and feedlot entry, are predictable events and, to some extent, can be managed. Stress management in cattle has two major components: (1) management of the cause of stress and (2) management of the quantified changes seen in the animals caused by stress (NRC 1996). The most stressful time in the life of most calves that follow the conventional marketing channels is from weaning through the first month in the feedlot. Granted, for some calves that are grown on pasture prior to entering the feedlot, there may be a period of relatively low stress while on grass. Nonetheless, steps can be taken by producers to minimize stress of calves prior to and during the weaning process and also prior to shipping and feedyard entry. Reducing stress influences the health and well-being of the animal, ultimately enhancing the potential for improved animal performance. This paper discusses concepts and strategies for weaning and preconditioning beef calves to minimize stress and improve calf performance.}, keywords = {cattle, improved animal performance, low-stress, minimize stress, preconditioning, weaning}, url = {/files/bibliography/05-040ABS.pdf}, author = {Mathis, C.P. and Waggoner, J.W. and E.L. Fredrickson} } @article {50599, title = {Limiting cheaters in mutualism: evidence from hybridization between mutualist and cheater yucca moths}, journal = {Proceedings of the Royal Society B}, volume = {272}, year = {2005}, note = {//USDA//LTER IV//Entered 01/09/2006}, month = {2005}, pages = {2195-2201}, abstract = {

Mutualisms are balanced antagonistic interactions where both species gain a net benefit. Because mutualisms generate resources, they can be exploited by individuals that reap the benefits of the interaction without paying any cost. The presence of such {\textquoteleft}cheaters{\textquoteright} may have important consequences, yet we are only beginning to understand how cheaters evolve from mutualists and how their evolution may be curtailed within mutualistic lineages. The yucca{\textendash}yucca moth pollination mutualism is an excellent model in this context as there have been two origins of cheating from within the yucca moth lineage. We used nuclear and mitochondrial DNA markers to examine genetic structure in a moth population where a cheater species is parapatric with a resident pollinator. The results revealed extensive hybridization between pollinators and cheaters. Hybrids were genetically intermediate to parental populations, even though all individuals in this population had a pollinator phenotype. The results suggest that mutualisms can be stable in the face of introgression of cheater genes and that the ability of cheaters to invade a given mutualism may be more limited than previously appreciated.

}, keywords = {article, cheater, exploitation, hybridization, insect, population ecology, insect, Tegeticula, insect, yucca moth, journal, obligate pollination mutualism, pollination mutualism, yucca moth, pollination, yucca moth, yucca moth, cheater, yucca moth, mutualism, yucca moth, mutualist, yucca moth, Tegeticula, Yucca, pollination, Yucca, reproduction, Yucca, yucca moth}, doi = {10.1098/rspb.2005.3201}, url = {files/bibliography/JRN00428.pdf}, author = {K. A. Segraves and David M. Althoff and Pellmyr, Olle} } @conference {50610, title = {Linking ecological processes adn environmental impacts across scales: Coastal ecology and energy development in the Caspian Sea}, booktitle = {Ecological Society of American Abstracts Annual Meeting}, year = {2005}, month = {August 7, 2005}, pages = {CDROM}, abstract = {Coastal regions, such as the Caspian Sea and the Gulf of Mexico face a multitude of serious environmental challenges, including energy development, overfishing and invasive species. The largest oil discovery in the past 30 years was found in the North Caspian Sea, home to the endemic Caspian Seal and source of more than 90\% of the world{\textquoteright}s caviar. Coastal ecology is organized by the cross-scale interactions of climate and geology, fluctuating population dynamics and local to global anthropogenic impacts, but there is considerable disagreement concerning the relative importance of local and global controls on ecological processes. This symposium will bring together leading scientists from the Former Soviet Union, Iran, Europe and North America to compare hotly debated aspects of coastal ecology relevant to energy development in the Caspian Sea and the Gulf of Mexico, including changing freshwater, nutrient and pollutant inputs, status of sturgeon and seals, and impacts of Mnemiopsis leidyi.}, keywords = {Caspian Sea, ecological}, author = {S. Tartowski and T.J. Butler and V. Bashkin} } @conference {50612, title = {Livestock as land management tools: weed control using goats}, booktitle = {Proceedings of the Annual Conference of the Quivira Coalition}, year = {2005}, month = {January 13, 2005}, abstract = {Livestock can have both desirable and undesirable impacts on vegetation and rangeland. Use of livestock to rehabilitate range and riparian ecosystems represents one aspect of the broader role of ranchers as land managers, rather than the more narrow role as livestock producers. Invasive species are a significant problem on western rangelands and salt cedar is a particularly damaging species that has infested riparian areas throughout the Southwest. Traditionally, chemical and mechanical methods are used to control salt cedar, but biological control methods are being developed and applied at several sites in New Mexico. The use of goats for the biocontrol of weeds is expanding rapidly, with new opportunities for commercial goatherders. This workshop will describe the effects of goats used to control salt cedar in an experimental project at San Acacia on the Rio Grande. This is the first study to quantify the damage done to salt cedar as well as the impact on other plant species. The details of managing goats for weed removal, including stocking rate, control of herd movements, timing of browsing and protection of desirable species will be presented. Management of livestock for commercial weed control and business aspects of ranchers contracting as land managers will be discussed by Sarah Harris of Western Weedeaters, a successful commercial operation. Guidelines and advice for initiating use of goats for weed control will assist both ranchers and land managers in deciding whether and how to use goats to control weeds in specific situations.}, keywords = {goats, land management tools, livestock, weed control}, author = {S. Tartowski and Harris, S.} } @booklet {50609, title = {Livestock as Tools for Ecological Restoration: Using Goats to Control Salt Cedar}, howpublished = {Jornada Trails}, volume = {9}, number = {2}, year = {2005}, month = {October 2005}, pages = {2}, address = {Las Cruces, NM}, abstract = {Salt Cedar (Tamarix spp.) has invaded riparian areas throughout the Western United States and has been reported to increase evapotranspiration, increase fire frequency, reduce habitat values, and replace native plant species. Herbicides and mechanical clearing are the main methods used to remove salt cedar. Goats readily browsed salt cedar, Russian olive and undesirable weeds in experimental plots along the Rio Grande, while maintaining weight and health. Nearly every salt cedar plant was damaged by browsing, but goats had an especially severe impact on resprouts, removing about half of the above ground vegetation. Goats had much less impact on large dense salt cedar, but cleared out the understory, reducing laddering fuels, improving access for recreation and reducing costs for subsequent mechanical or manual clearing. After two years of goat treatment, the width of salt cedars was reduced by about 35\%, but only about 4\% of the large salt cedars were killed. It may take several more years of goat browsing to deplete the root reserves of salt cedar sufficiently to increase tree mortality. Grass cover, especially native grama grasses (Bouteloua barbatus and B. aristoides), increased from less than 1\% before goat browsing to about 20\% after goat browsing.}, keywords = {ecological, goats, livestock, salt cedar}, author = {S. Tartowski} } @article {50618, title = {Low-temperature, scanning electron microscopy of artificial snow}, journal = {Scanning}, volume = {27(2)}, year = {2005}, month = {March 1, 2005}, pages = {63-64}, abstract = {Low temperature scanning electron microscopy (LTSEM) has been used to observe and characterize fresh and metamorphosed naturally formed snow crystals1. These crystals form in the atmosphere by a process known as vapor deposition, in which molecules of water vapor (gas) bind to form a crystal (solid). No transitional liquid phase occurs. Atmospheric temperature during crystal formation largely influences the structure of the crystals, which may develop into dendrites, plates, columns needles, or irregular crystals, whereas the time of formation influences their sizes. Once formed, the descending snow crystals may encounter super-cooled cloud droplets. The droplets impact and immediately freeze to the surface of the crystal, which is then referred to as being rimed. Continuation of this process, which is known as accretion, results in a mass of frozen droplets, referred to as graupel. Artificial snow appears as microscopic pellets. The types of snow guns and use of ice nucleating agents, influence the sizes of the pellets and the efficiency of production. Artificial snow, which results from the freezing of a liquid, most closely resembles the natural process of accretion that results in riming and graupel. Because sufficient time for vapor deposition seldom occurs, artificial snow does not exhibit the crystalline shapes found in natural snow.}, keywords = {crystals, electron, LTSEM, microscopy, scanning, snow}, url = {/files/bibliography/05-005.pdf}, author = {W.P. Wergin and E. R. Erbe and A. Rango and J. Foster and C.D. Pooley} } @article {50637, title = {Land management in the American Southwest: A state-and-transition approach to ecosystem complexity}, journal = {Environmental Management}, volume = {34}, number = {1}, year = {2004}, month = {July 1, 2004}, pages = {38-51}, abstract = {

State-and-transition models are increasingly being used to guide rangeland management. These models provide a relatively simple, management-oriented way to classify land condition (state) and to describe the factors that might cause a shift to another state (a transition). There are many formulations of state-and-transition models in the literature. The version we endorse does not adhere to any particular generalities about ecosystem dynamics, but it includes consideration of several kinds of dynamics and management response to them. In contrast to previous uses of state-and-transition models, we propose that models can, at present, be most effectively used to specify and qualitatively compare the relative benefits and potential risks of different management actions (e.g., fire and grazing) and other factors (e.g., invasive species and climate change) on specified areas of land. High spatial and temporal variability and complex interactions preclude the meaningful use of general quantitative models. Forecasts can be made on a case-by-case basis by interpreting qualitative and quantitative indicators, historical data, and spatially structured monitoring data based on conceptual models. We illustrate how science- based conceptual models are created using several rangeland examples that vary in complexity. In doing so, we illustrate the implications of designating plant communities and states in models, accounting for varying scales of pattern in vegetation and soils, interpreting the presence of plant communities on different soils and dealing with our uncertainty about how those communities were assembled and how they will change in the future. We conclude with observations about how models have helped to improve management decision-making.

}, keywords = {Chihuahuan Desert, community dynamics, desert grassland, grazing management, rangeland, resilience, simulation models, soil maps, thresholds}, doi = {10.1007/s00267-004-0047-4 }, url = {/files/bibliography/04-015.pdf}, author = {Brandon T Bestelmeyer and Joel R. Brown and Jeffrey E. Herrick and D. Trujillo and Kris Havstad} } @conference {50682, title = {Lewis and Clark{\textquoteright}s encounters with wildlife and Native Americans: A GIS analysis}, booktitle = {89th Annual Meeting, Ecological Society of America}, year = {2004}, month = {August 1, 2004}, pages = {Abstract p. 286}, address = {Portland, OR}, abstract = {It is often difficult to determine human influences on ecosystems before Euro-American settlement. The Lewis and Clark journals contain some of the earliest and detailed written descriptions of a large part of the United States and offer one way to assess the past. We used the journal entries to map Lewis and Clark{\textquoteright}s encounters with wildlife and the human population and performed a GIS analysis to determine human influences on wildlife. Species richness was higher in areas with few human settlements, such as the west central part of the Plains, while the fewest number of species were encountered in areas with denser human population, along the Columbia River and west to the Pacific coast. With increasing distance from human settlements and with decreasing settlement densities, abundance of large mammals increased. Bison, elk, grizzly and wolves were predominantly found in the plains. Elk, bison, bighorn sheep and wolves were absent from the Columbia Basin. The results show that humans had considerable influence over wildlife distribution and abundance, even under relatively low human population densities. This insight into historical wildlife distribution and abundance will offer a better understanding of the historical reference condition on which current management regimes are often based. The study also shows that human influences should not be underestimated when investigating historical ecological conditions.}, keywords = {ecosystems, GIS, human influendes, Lewis and Clark, Native Americans, wildlife}, author = {Andrea S. Laliberte and Ripple, W.J.} } @article {50688, title = {Long-term measurements of CO2 flux and evapotranspiration in a Chihuahuan desert grassland}, journal = {Journal of Arid Environments}, volume = {60}, year = {2004}, month = {September 24, 20}, pages = {423-436}, abstract = {We measured CO2 and evapotranspiration (ET) fluxes above a Chihuahuan desert grassland from 1996 through 2001. Averaged across six years, this ecosystem was a source (positive flux) of CO2 in every month. Over that period, sustained periods of carbon uptake (negative flux) were rare. Averaged across all months, we estimated that CO2 was being released into the atmosphere at a rate of +1.5 g CO2 m-2 d-1 (+0.40 g Cm-2 d-1) or +533 g CO2m-2 yr-1 (+145.3 g Cm-2 yr -1). Average ET was 299mm yr -1 with a monthly range of 0.15mm d-1 in December to 2.15mm d-1 in August.}, keywords = {Bouteloua eriopoda, carbon exchange, CO2 flux, desert grassland, evapotranspiration}, url = {/files/bibliography/04-081.pdf}, author = {Mielnick, P. and W.A. Dugas and K. A. Mitchell and Kris Havstad} } @article {50694, title = {Livestock grazing effects on ant communities in the eastern Mojave Desert, USA}, journal = {Ecological Indicators}, volume = {4}, number = {3}, year = {2004}, month = {September 1, 200}, pages = {199-213}, abstract = {

The effects of livestock grazing on composition and structure of ant communities were examined in the eastern Mojave Desert, USA for the purpose of evaluating ant communities as potential indicators of rangeland condition. Metrics for ant communities, vegetation, and other ground-cover elements were evaluated as a function of distance from livestock water tanks, which represents a gradient in level of livestock activity in desert settings. Data were collected at six isolated water tanks used by cattle during early summer, with seven plots (90m \× 90m; 100 pitfall traps) per tank. Thirty-eight species of ants were recorded, with an average of 14 ant species per plot. Ant species richness did not differ as a function of distance from the water tank. Also, overall species composition, as measured by a similarity index for species presence/absence for paired-comparisons of plots, did not show differences attributable to the gradient in grazing impact. In contrast, the relative abundance of several taxa and functional groups was significantly related to distance from the water tank. The predominant pattern was for the greatest abundance to occur at the water tank, with little difference in ant abundance among plots away from the water tank. This pattern was shown by the abundant ants species, Conomyrma bicolor and Pheidole tucsonica, and the groups Conomyrma spp., Pheidole spp., homopteran tenders, and plant foragers. However, two species, Aphaenogaster megommata and Monomorium wheelerorum showed the greatest relative abundance at a distance away from the water tank. A number of ant metrics were significantly related to ground-cover metrics (R2\> 0.5). Organic debris was the variable most frequently related significantly to ant abundance metrics, always in a positive direction, followed by cover for perennial grasses, annual forbs, and shrubs, and bare patch size. Ant community metrics in the study region appear to have little potential to serve as indicators of rangeland condition because differences were evident primarily in severely degraded localized conditions rather than in intermediate widespread conditions.

}, keywords = {ant, Ant community, Bare patches, Bioindicator, indicator, livestock grazing, Mojave Desert, Rangeland condition, vegetation}, doi = {10.1016/j.ecolind.2004.03.004}, url = {/files/bibliography/04-076.pdf}, author = {M. S. Nash and Bradford, D.F. and Franson, S.E. and A.C. Neale and Walter G. Whitford and Heggem, D.T.} } @conference {50731, title = {Landscape-scale analyses provide new insights into desertification}, booktitle = {19th Annual Symposium of the US Regional Association of the International Association for Landscape Ecology: Transdisciplinary Challenges in Landscape Ecology}, year = {2004}, month = {March 30-April 2}, address = {Las Vegas, NV}, abstract = {Desertification, or the invasion of woody plants into perennial grasslands with associated changes in ecosystem stability, is a pervasive problem that affects arid and semiarid systems worldwide. Although many studies have been conducted on woody plant invasion, we still lack a basic understanding of controls on the spatial and temporal variation in desertification dynamics at multiple scales. Our objective was to develop and test a new conceptual framework of woody plant invasion that explicitly includes a hierarchy of interacting scales. Our model includes landscape characteristics, such as connectivity, interacting with both fine scale processes (e.g., competition) and broad-scale drivers (e.g., climate) to generate cross-scale interactions. We provide support for our model from a combination of long-term studies, process-based experiments, and integrative simulation model analyses conducted in southern New Mexico. Results from >100 permanent quadrats established in the early 1900{\textquoteright}s show both high spatial and temporal variation in patterns in shrub invasion and grass persistence through time. Much of this variation was explained by landscape-scale features related to connectivity of shrubs (i.e., distance to the nearest shrubland when a quadrat was established). Experimental results show the importance of variation in herbivory on grass survival at grass-shrub ecotones with high spatial variation among locations. An integrated simulation model and multiscale experiments are being used to examine key processes and constraints operating across scales. Thus, our results support the cross-scale landscape model of desertification and provide a framework for understanding and predicting variation in woody plant invasion dynamics.}, keywords = {cross-scale, desertification, invasion, landscape-scale, woody plants}, url = {http://abstracts.co.allenpress.com/pweb/usiale2004}, author = {Jin Yao and Debra C. Peters and Kris Havstad and Brandon T Bestelmeyer} } @inbook {50774, title = {Leaf structure}, booktitle = {Encyclopedia of Plant and Crop Science}, year = {2003}, note = {//??//LTER IV// Updated 12/17/2005ProCite field[6]: In}, month = {2003}, pages = {638-641}, publisher = {Marcel Dekker}, organization = {Marcel Dekker}, address = {New York}, abstract = {//NONE//NONE//Listed in LTER IV annual report}, keywords = {book, books, chapter, chapters, plant, leaf structure, report, reports}, author = {V. P. Gutschick and Kay, L. E.}, editor = {Goodman, R. N. ed.} } @proceedings {50777, title = {Long-term dynamics of a degraded arid shrubland: Delayed responses and the importance of spatial processes}, year = {2003}, month = {July 26-August 1}, pages = {353-355}, address = {Durban, South Africa}, abstract = {Many studies in rangelands are conducted over time periods that are too short to capture the inherent spatial and temporal variability of these systems. Extreme or pulse events that result in infrequent responses are one example that requires long-term data, but delayed responses are another that are less well-studied. Our objective was to examine the response of Chihuahuan Desert rangelands following the removal of shrubs and lagomorphs over a period of >60 years in order to capture both extreme events and delayed responses to those events. Three blocks of 16 21.3 x 21.3 m plots were established in 1938-39 to evaluate vegetation dynamics in response to shrub removal and lagomorph exclusion. Basal cover of perennial grass species did respond to treatments, especially shrub removal treatments. However, there were two important observations relative to these quantified responses. First, differences were not evident for at least 50 years. Spatially explicit processes, such as seed dispersal into these experimental plots from adjoining areas, were likely the important constraint on reestablishment of perennial grasses. Second, the temporal variability in basal cover of grasses and canopy cover of shrubs in control plots illustrate the inherent dynamics of this arid shrubland. An extreme extended drought period occurred from 12 to 17 years after the experiment was established. This climatic variability masked treatment responses until nearly 50 years after they were first implemented. In this system, we do not appreciate possible effects of vegetation management practices until they are examined during and following episodic, extreme, and acute disturbances that characterize this environment.}, url = {/files/bibliography/03-032.pdf}, author = {Kris Havstad and Debra C. Peters and L. W. Murray} } @article {50778, title = {Long-term ecological monitoring}, journal = {Arid Land Research and Management}, volume = {17}, number = {4}, year = {2003}, month = {October 1, 2003}, pages = {389-400}, abstract = {The intent of long-term monitoring is to document changes in important properties of biological communities. At the least, a long-term monitoring system should be designed to detect long-term trends in three key attributes: soil and site stability, hydrologic function, and the biotic integrity of the system. There are four basic guidelines for developing integrated soil-vegetation monitoring systems for rangelands. These are (1) identifying a suite of indicators which are consistently correlated with the functional status of one or more critical ecosystem processes and/or properties, (2) selecting base indicator on site-specific objectives and resource concerns and inherent soil and site characteristics, (3) using spatial variability in developing and interpreting indicators to make them more representative of ecological processes, and (4) interpreting indicators in the context of an understanding of dynamic, nonlinear ecological processes. To the extent possible, indicators should reflect early changes in ecological processes and indicate that a more significant change is likely to occur. In addition to these guidelines, measurements included in long-term monitoring systems should be rapidly applied, simple to understand, inexpensive to use, and quantitatively repeatable.}, url = {http://journalsonline.tandf.co.uk/media/m3t1fartxndvtn6ugxuq/contributions/8/d/7/u/8d7uxtp8vpt4tqku.pdf}, author = {Kris Havstad and Jeffrey E. Herrick} } @article {50794, title = {Lizard community structure across a grassland - creosote bush ecotone in the Chihuahuan Desert}, journal = {Canadian Journal of Zoology}, volume = {81}, year = {2003}, note = {//NMSU//LTER IV//}, month = {2003}, pages = {1829-1838}, abstract = {

I investigated the distribution and abundance of lizard species (Aspidoscelis inornatus, Aspidoscelis tesselatus, Aspidoscelis tigris, Aspidoscelis uniparens, Cophosaurus texanus, Crotaphytus collaris, Eumeces obsoletus, Gambelia wislizenii, Holbrookia maculata, Phrynosoma cornutum, Sceloporus magister, and Uta stansburiana) across a desert grassland -- creosote bush (Larrea tridentata) ecotone in Dona Ana County, New Mexico. The ecotonal area in the Jornada del Muerto basin has increased dramatically in the past 150 years because of the rapid spread of creosote bush. I asked four related questions: how large and where is the ecotone based on vegetative structure, and do lizard abundance and diversity change across the ecotone? Vegetation data were analyzed using discriminate function analysis to determine the extent of the ecotone. Changes in lizard abundance across the ecotone were analyzed by analysis of variance. During two summers, 677 individual lizards of 9 genera and 12 species were captured. Lizard abundance increased with increasing distance from the ecotone and was similar in grassland and creosote bush habitat. Grasslands had higher species richness than both the creosote bush and ecotone habitats. Grassland sites had greater habitat heterogeneity than did creosote bush sites. No ecotone specialist species were detected, and all common lizard species could be found in each habitat. Three potential explanations for decreased abundance in the ecotone are presented: (1) increased risk of predation, (2) decreased prey abundance, and (3) lack of species-specific microhabitat requisites.

}, keywords = {article, articles, community, grassland, community, Larrea, community, lizard, ecotone, grassland - creosotebush, ecotone, lizard, journal, journals, lizard, Aspidoscelis, lizard, Cophosaurus, lizard, Crotaphytus, lizard, Eumeces, lizard, Gambelia, lizard, Holbrookia, lizard, Phrynosoma, lizard, Sceloporus, lizard, Uta, lizard,Cnemidophorus, shrub, creosotebush, Larrea}, doi = {10.1139/z03-184 }, url = {files/bibliography/JRN00389.pdf}, author = {Menke, Sean B.} } @article {50831, title = {Long-term and large-scale perspectives on the relationship between biodiversity and ecosystem}, journal = {BioScience}, volume = {53}, number = {1}, year = {2003}, month = {January 1, 2003}, pages = {89-98}, abstract = {

A growing body of literature from a variety of ecosystems shows strong evidence that various components of biodiversity have significant impacts on ecosystem functioning. However, much of this evidence comes from short-term, small-scale experiments in which communities are synthesized from relatively small species pools and conditions are highly controlled. Extrapolation of the results of such experiments to longer time and larger spatial scales\¿-those of whole ecosystems\¿-is difficult because the experiments do not incorporate natural processes such as recruitment limitation and colonization of new species. In this section of this special feature on the Long-Term Ecological Research (LTER) network, we show how long-term study of planned and accidental changes in species richness and composition suggests that the effects of biodiversity on ecosystem functioning will vary over time and space. More importantly, we also highlight areas of uncertainty that need to be addressed through coordinated, cross-scale and cross-site research.

}, url = {http://intranet.lternet.edu/archives/documents/journal_pubs/Symstad_BioScience_2003.pdf}, author = {A.J. Symstad and F.S. Chapin III and D.H. Wall and K.L. Gross and L. Huenneke and Mittelbach, G.G. and Debra C. Peters and Tilman, G.D.} } @proceedings {50868, title = {The long-distance A {\textquoteleft}transportable fraction{\textquoteright} of the vertical flux of wind-transported dust}, volume = {Publication 02-2}, year = {2002}, note = {//??//LTER IV// Listed in LTER IV annual reportProCite field[6]: In}, month = {2002}, abstract = {A "lumped control volume" approach is used here to gain understanding of fugitive dust sources including wind erosion and road dust emission. This case considers dust generated from a road surface. A semiempirical model expresses in a simple expression the "transportable fraction" of dust generated at ground level and carried by the wind.}, keywords = {abstract, abstracts, aeolian processes, wind-transported dust, conference, conference proceedings, conferences, proceeding, proceedings, wind transport}, author = {D. E. Gillette}, editor = {Lee, Jeffrey A. and Teddy M. Zobeck} } @conference {50871, title = {The landscape as probability layers, or why is this plant here and not there?}, booktitle = {17th Annual Symposium, US-International Association for Landscape Ecology}, year = {2002}, month = {April 23-26, 200}, pages = {64}, address = {Lincoln, NE}, abstract = {Plant spatial pattern is determined by complex interactions between a number of factors. Seed dispersal and plant interactions (competition and facilitation) are explicitly spatial. Species-specific environmental heterogeneity adds additional complexity. The landscape can be visualized as a series of superimposed layers describing the probability of establishment, growth and mortality for a particular species at any point in the landscape based on the interaction between environmental heterogeneity and the locations of already established plants. An individual-based model realizing this concept was developed with the objective of untangling the contribution of different spatial plant processes to particular configurations of individuals on the landscape. The model was designed to be extremely flexible so that a wide variety of seed dispersal patterns, plant interactions, and environmental responses could be included. A secondary goal was to create realistic artificial landscapes based on known processes that can be used to test ecological analysis methods. This probability-based spatial approach can be applied to a variety of ecosystems and theoretical questions and has produced novel insights into the effect of various processes on plant spatial pattern.}, author = {Sarah Goslee} } @conference {50905, title = {Landscape-level phytochemistry of a Chihuahuan Desert shrubland}, booktitle = {Annual Meeting, Phytochemical Society of North America}, year = {2002}, month = {July 20-24, 2002}, pages = {49 (Abstract No. 17)}, address = {Merida, Mexico}, abstract = {Shrub volatiles play a significant ecological role in desert rangelands. Activities attributed to these compounds include pollinator attraction, herbivore repulsion, allelopathy, pathogen inhibition, and microclimate modification. In recent years, we have constructed volatile chemical profiles of a number of genera, including Ceratoides, Chrysothamnus, Dalea, Drymaria, Dyssodia, Fallugia, Florensia, Gutierrezia, and Psorothamnus. Presently, we are utilizing these data to construct a spatial database of the volatile compounds present on sites within the 78,266 ha Jornada Experimental Range (JER), a desert rangeland research facility near Las Cruces, NM. Coupling these data with vegetative maps, soil maps, livestock grazing patterns, weather and climate data, and other information available at the Jornada Experimental Range will facilitate examination of relationships between plant volatile composition, shrub survival, plant-plant competition, and plant-herbivore interactions.}, author = {M.E. Lucero and Richard E. Estell and M.R. Tellez and E.L. Fredrickson and Kris Havstad} } @conference {50910, title = {Long-term changes in carbon pools accompanying shrub invasion of a desert grassland: the Jornada Experimental Range, 1850-today}, booktitle = {87th Annual Meeting, Ecological Society of America}, year = {2002}, month = {August 4-9, 2002}, pages = {215}, address = {Tucson, AZ}, abstract = {Coincident with a worldwide increase in the abundance of woody plants within former grasslands, desert grasslands throughout the southwestern U.S. have experienced a substantial increase in the abundance of shrubs during the last century. The displacement of grasslands with grass-shrublands has had important implications for ecosystem carbon cycling and rates of carbon sequestration. Building on a history of biogeochemistry research conducted at the Jornada Experimental Range in southern New Mexico, we measured and modelled aboveground and belowground carbon storage in black grama grasslands (Bouteloua eriopoda) and mesquite (Prosopis glandulosa) and creosotebush (Larrea tridentata) shrublands across the Jornada basin. We combined the simulation modeling predictions of the CENTURY model with data from recovered historical vegetation maps of 1858, 1915, 1928 and modern vegetation maps. Our results support the hypothesis that shrub encroachment into grasslands increases storage of belowground carbon. Landscape-level mapped estimates of carbon pools indicate that the desert grassland ecosystem of the Jornada basin may have served as a carbon sink during the last century.}, author = {K. A. Mitchell and Debra C. Peters and Curtis H. Monger and Jeffrey E. Herrick} } @conference {50924, title = {Landscape-scale consequences of patch-scale invasion success or failure}, booktitle = {US-International Association for Landscape Ecology}, year = {2002}, month = {April 23-26, 200}, pages = {109}, address = {Lincoln, NE}, abstract = {Shrub invasion into perennial grasslands has occurred throughout many arid ecosystems in the US and abroad. Although various factors contributing to invasion have been well studied, there is little understanding of the spatial variation in shrub success into different plant communities. The objective of this study was to examine differential invasion success by the shrub, creosotebush, into grasslands dominated by different species. The study was conducted at the Sevilleta LTER site in central New Mexico, USA, where the landscape consists of a mosaic of patches and ecotones between several grass and shrub species. Sampling was conducted by geo-referencing the location of all shrub plants within patches dominated either by blue grama, a dominant species in the shortgrass steppe, or by black grama, a dominant of the Chihuahuan Desert. Vegetation was sampled within and outside of each shrub patch. Results show that creosotebush-black grama ecotones are diffuse, consisting of a complex mosaic of grasses and shrubs. By contrast, ecotones between creosotebush and blue grama are distinct with very few shrub plants found within patches dominated by blue grama. Consequences of these patch-scale interactions for landscape-scale patterns in shrub invasion and grass resistance are discussed.}, author = {Debra C. Peters} } @proceedings {50952, title = {Low-temperature scanning electron microscopy of irregular snow crystals}, volume = {8}, year = {2002}, month = {December 10, 200}, pages = {722-723}, abstract = {Snow crystals occur in eight basic types: columns, needles, plates, dendrites, irregular crystals, graupel, hail and ice pellets. Most of these types have been described and photographed. However, our understanding of "irregular crystals" remains vague because the limited resolution and depth-of-field associated with the light microscope have prevented investigators from fully characterizing and clearly illustrating the features of these crystals. Our study used a field-emission scanning electron microscope (FESEM) equipped with a cold stage to document the structural features, physical associations, and atmospheric metamorphosis of irregular snow crystals. Snow samples, consisting of freshly fallen snowflakes, were collected from six different locations where air temperatures ranged from -5 degrees C to 0 degress C. Crystals believed to correspond to irregular crystals appeared as short, irregular hexagons measuring 60 to 90 um across when viewed from the a-axis. Their length (c-axis) rarely exceeded the diameter. The irregular crystals were occasionally found as secondary particles on other larger forms of snow crystals. However, they most frequently occurred as aggregates consisting of more than 100 irregular crystals. In the aggregates, the irregular crystals had their c-axes oriented parallel to one another and collectively tended to form columnar structures. Occasionally, the aggregates exhibited rounded facets along one side, suggesting atmospheric metamorphoses and unidirectional fall. In extreme cases of metamorphoses, the aggregates would be difficult to distinguish from graupel. Frost consisting of irregular crystals was also encountered, suggesting that atmospheric conditions that favor this form of growth also occur terrestrially. Results obtained with low temperature FESEM suggested that crystals which were previously designated as "irregular crystals" have distinctive features that can be used to characterize and distinguish them from other types of snow crystals.}, author = {W.P. Wergin and A. Rango and J. Foster and E. R. Erbe and C.D. Pooley} } @article {50974, title = {Local and regional-scale responses of ant diversity to a semiarid biome transition}, journal = {Ecography}, volume = {24}, number = {4}, year = {2001}, month = {December 1, 2001}, pages = {381-392}, abstract = {

The locations of biome transitions and ecotones are frequently defined by the rapid shift from one form of dominant vegetation to another. The composition of animal taxa is predicted to shift parallel with that of dominant plants, and species diversity is predicted to be greater in transitional zones than in adjacent areas. We asked whether ant species diversity and composition supported these predictions across a biome transition between shortgrass steppe and Chihuahuan Desert vegetation. Neither species richness nor diversity was highest at the biome transition region as a whole or within habitats in the biome transition. The biome transition region was not intermediate in ant species composition or in the representation of different faunal complexes. The community similarity between matched habitats shared between the biome transition zone and adjacent regions was less than that between distinct habitats occurring within regions. A zoogeographic transition for ants may occur to the nort of the phytogeographic transition and may be coincident with the northern limits of monsoonal precipitation patterns. In contrast, the phytogeographic transition may be related to less extreme climatic variation within the monsoonal region occurring further south.

}, keywords = {ants, Desert insects, grasslands, Habitats, Insect communities, shrublands, species diversity, Steppes, Taxa}, doi = {10.1034/j.1600-0587.2001.d01-194.x}, url = {/files/bibliography/01-015.pdf}, author = {Brandon T Bestelmeyer and J.A. Wiens} } @conference {51029, title = {Landscape consequences of small-scale disturbances at a grassland-shrubland ecotone}, booktitle = {16th Annual Symposium, US-International Association of Landscape Ecology}, year = {2001}, month = {April 25-29, 200}, pages = {200}, address = {Tempe, AZ}, abstract = {The objective of this study was to evaluate the role of small-scale disturbances within different patch types to landscape-scale patterns in species composition and dominance at a shortgrass steppe-Chihuahuan Desert ecotone. Species removals were conducted at the Sevilleta LTER in central New Mexico within five different patch types where communities are dominated or codominated by one of two perennial grasses (blue grama, black grama) and one shrub (creosotebush). Within each patch type, all plants of the dominant species were removed from five 3m x 4m plots starting in 1995; five control plots were also located within each patch type. Cover and density by species have been estimated annually. Similarity indices were used to compare patch-scale patterns in species composition with the landscape mosaic. Annuals dominated all removal plots one year after removals were initiated. Subsequent recovery patterns depended upon the dominant species removed. Blue grama removal resulted in establishment and growth of perennial grasses, whereas removal of black grama promoted recovery by perennial forbs. Removal of creosotebush in mixed communities with black grama resulted in recovery by perennial forbs, grasses, and shrubs whereas removal of this species in shrub-dominated communities resulted in little change in the vegetation. These results indicate that mortality of dominant species by small-scale disturbances has dramatic effects on vegetation patterns that may alter the landscape mosaic at this arid-semiarid ecotone.}, author = {Debra C. Peters} } @proceedings {51053, title = {Locally led conservation activities: Developing a soil quality assessment tool}, year = {2001}, month = {May 24-29, 1999}, pages = {529-534}, address = {Purdue University and the USDA-ARS National Soil Erosion Research Laboratory}, abstract = {Farmers base many management decisions on a variety of personal observations of their crops and soils. However, there was no soil assessment procedure applicable to farms across the country to help farmers record these observations and to use them to guide their future management decisions. To address this need, the Soil Quality Institute of the USDA-NRCS, university research and USDA-CES partners in Oregon and Maryland developed the Soil Quality Card Design Guide. Using the guide, facilitators followed a nine-step meeting procedure to help farmers identify locally important soil quality indicators, develop descriptive terms for soil quality assessments, and design the format of their soil quality card. Seven cards were developed by local groups of farmers during the period 1997 to early 1999. The farmer meeting provides an opportunity for USDA-NRCS, USDA-CES, conservation districts, producers and others to jointly create soil quality cards for farmers in each unique cropping region of the country. The collaborative process used to create the cards offers locally led conservation opportunities for dialogue and idea sharing, thus blending the scientific knowledge of conservationists and soil scientists with the common-sense experience of producers. Farmers can use soil quality cards to assess changes in soil quality resulting from different management systems and to track changes from year to year. Agricultural professionals, educators, students and others with an interest in soil quality and the impact of management practices on soil can use the cards to enhance communication and learning.}, keywords = {indicators, management systems, soil assessment procedure, Soil Quality Card Design Guide}, url = {/files/bibliography/01-050.pdf}, author = {A.J. Tugel and Seiter, S. and Friedman, D. and J. Davis and Dick, R.P. and McGrath, D. and Weil, R.R.}, editor = {E.E. Stott and R.H. Mohtar and G.C. Steinhardt} } @article {51065, title = {Large-scale related effects on the determination of plant communities and relationships with environmental variables}, journal = {Community Ecology}, volume = {1}, number = {2}, year = {2000}, month = {July 1, 2000}, pages = {157-164}, abstract = {

The influence of scale on the discernment of plant community patterns was examined using vegetation-environment data collected from a subalpine wet meadow in south-coastal British Columbia. Species cover data were recorded in 225, 0.25m2 quadrats systematically located at 5m intervals in a 40m x 120m sampling grid. Environmental data consisted of quadrat elevations as well as measured and Kriged estimates of five soil variables (carbon content, pH, electrical conductivity, percent sand, and percent clay). Sampling scale was adjusted by aggregating neighboring quadrats into composite sampling units; analytical scale was altered by varying the intercept level in dendrograms from minimum increase of sum of squares cluster analysis of the vegetation data corresponding to the different sampling scales. The resulting classifications were evaluated for their ability to explain variation in the vegetation data and in the environmental data. The vegetation variation explained by the classifications was highest at the smallest sampling scale indicating that vegetation heterogeneity is fine grained. In contrast, the environmental variation explained was higher for the classifications based on the larger composite sampling units implying a coarser scaling of abiotic conditions within the study area. These results were consistent with the recognition of three main zones along a drainage gradient within the sampling grid--upper mixed-forb, middle heath and lower sedge. This study reaffirms the need for consideration of alternatives both in field sampling and analytical phases of vegetation research to ensure that description and interpretation of patterns adequately address study objectives and that vegetation-environment relationships are more completely investigated from a hierarchical perspective.

}, keywords = {Environmental valiance explained, Grain size, Minimum increase of sum of squares cluster analysis, Principal component analysis, Sampling scale, Vegetation classificatio}, doi = {10.1556/ComEc.1.2000.2.5}, url = {/files/bibliography/00-012.pdf}, author = {Drewa, P.B. and Bradfield, G.E.} } @article {51099, title = {Length-scale analysis of surface albedo, temperature, and normalized difference vegetation index in desert grassland}, journal = {Water Resources Research}, volume = {36}, number = {7}, year = {2000}, note = {//USDA//LTER III//}, month = {2000}, pages = {1757-1765}, abstract = {

The Jornada Experiment (JORNEX) on the Jornada Experimental Range in southern New Mexico aims at the description of the surface energy balance of a desert grassland ecosystem. A large volume of both field and remote sensing data has been collected from 1995 to 1998. Airborne Daedalus scanner data with a spatial resolution of 4 m have been used to infer the following land surface characteristics: surface temperature, albedo, and normalized difference vegetation index (NDVI). These land surface characteristics can be used as input for land surface models. However, land surface models work with very coarse grid cells of at least 50 x 50 km, in contrast to high-resolution remote sensing data. Also, land surface models are generally based on nonlinear algorithms. Both restrictions lead to scale problems. One apparent question is how to scale up input remote sensing data to the much coarser resolution of the land surface model. The first step is to derive the length scale of the input land surface characteristics. The length scales of the land surface characteristics have been determined with the following two techniques: autocorrelation and wavelet analysis. Within the Jornada Experimental Range, three different sites with different vegetation characteristics were distinguished: grass, shrub, and a transition site with patches of both grass and shrub. The autocorrelation and wavelet analysis showed similar results for the shrub site. For the grass and transition site the wavelet analysis underestimated the length scale of the surface albedo and temperature. The length scale of the surface albedo was 35, 33, and 10 m for grass, transition, and shrub sites, respectively. The length scale of the surface temperature was 31, 20, and 8 m for grass, transition, and shrub sites, respectively. The length scale of the NDVI was 12, 6, and 5 m for grass, transition, and shrub sites, respectively. These small length scales could hamper the use of low-resolution remote sensing data for deriving input data for land surface models.

}, keywords = {article, articles, grassland ecosystem, also SEE , grassland ecosystem, surface energy baland, JORNEX, remote sensing, journal, journals, model, land surface, model, remote sensing, plant community, remote sensing, remote sensing, autocorrelation, remote sensing, Daedalus, remote sensing, JORNEX, remote sensing, NDVI, remote sensing, surface albedo, remote sensing, temperature, remote sensing, wavelet analysis, technique, autocorrelation, technique, remote sensing, technique, wavelet analysis, vegetation change, remote sensing}, doi = {10.1029/2000WR900028}, url = {files/bibliography/Rango2000-01.pdf}, author = {Pelgrum, Henk and T. J. Schmugge and A. Rango and Jerry Ritchie and William P. Kustas} } @inbook {51104, title = {Landscape Diversity}, booktitle = {Encyclopedia of Biodiversity}, volume = {3}, year = {2000}, month = {October 25, 2000}, pages = {648-658}, publisher = {Academic Press}, organization = {Academic Press}, address = {Princeton, NJ}, abstract = {While biodiversity is usually considered at the species level, maintenance of biodiversity requires management at higher levels of organization, particularly at the landscape scale. It is difficult to manage for each threatened species individually. Alternatively, management can focus on the ecosystems that contain these species, and on the landscapes where ecosystems are found. The relatively new discipline of landscape ecology provides insight into both landscape diversity and species diversity, and suggests a theoretical and practical basis for conservation planning. There are three basic characteristics of landscapes that affect their diversity: structure, function and dynamics. Structure is the most well-understood element of landscapes. It is also the most obvious- nearly any aerial view will show a mixture of different landforms, habitats, or vegetation types. The patch is the basic unit of landscape structure. The characteristics of patches and the spatial relationships among patches are important components of landscapes. The distributions of energy, materials, and species among patches differing in size, shape, abundance, and configuration are particularly important to patterns in diversity at the landscape scale. The other two elements of landscapes go beyond a description of spatial heterogeneity. Function is concerned with interactions among the spatial elements of a landscape, including flows of energy, materials, and species among patches. Landscape dynamics includes characteristics of both structure and function in order to examine changes in pattern and process over time. Conservation and management of biodiversity requires understanding of all three of these elements, including the effects of human activities on the system.}, keywords = {biodiversity, dynamics, function, landscape ecology, maintenance, management, structure}, url = {/files/bibliography/00-020.pdf}, author = {Debra C. Peters and Sarah Goslee}, editor = {Simon Asher (ed. Levin} } @article {51156, title = {Long-term influences of shrub removal and lagomorph exclusion on Chihuahuan Desert vegetation dynamics}, journal = {Journal of Arid Environments}, volume = {42}, number = {3}, year = {1999}, month = {July 1, 1999}, pages = {155-166}, abstract = {

Cover of perennial species in long-term experimental plots in a creosotebush (Larrea tridentata Sess. \& Moc. Ex DC.) dominated community in the Chihuahuan Desert was monitored for 56 years. Sixteen 21{\textperiodcentered}3{\texttimes}21{\textperiodcentered}3 m plots were established in 1938{\textendash}39 to evaluate the effects of lagomorph exclusion and shrub removal. Major dominant shrubs were individually severed at ground level and removed by hand in 1939, and this process was repeated after measuring plant cover in 1947, 1956, 1960, 1967, 1989, and 1995. Lagomorphs were excluded with poultry wire fencing. Shrub removal increased (p<=0{\textperiodcentered}05) the basal cover of two major desert grass species, black grama (Bouteloua eriopoda Torr.) and spike dropseed (Sporobolus contractus A.S. Hitch.) between 1939 and 1995, but differences were not evident until 50 years after initial treatment. Temporal effects of lagomorph exclusion were less pronounced than shrub removal. Clearly, shrub dominance has an extremely important and lasting role in determining vegetation community structure in this arid environment, even when above-ground shrub structures are periodically removed.

}, keywords = {black grama, Bouteloua eriopoda, creosotebush, desert ecology, Larrea tridentata}, doi = {10.1006/jare.1999.0516}, url = {/files/bibliography/660.pdf}, author = {Kris Havstad and Gibbens, Robert P. and Knorr, C.A. and L. W. Murray} } @article {51172, title = {Livestock activity and Chihuahuan Desert annual-plant communities: Boundary analysis of disturbance gradients}, journal = {Ecological Applications}, volume = {9}, number = {3}, year = {1999}, month = {August 1, 1999}, pages = {814-823}, abstract = {

The impact of domestic livestock on soil properties and perennial vegetation is greatest close to water points and generally decreases exponentially with distance from water. We hypothesized that the impact of livestock on annual-plant communities would be similar to that on perennial vegetation. We used multivariate analysis and semivariograms to locate boundaries and to determine the number and width of different annual-plant zones (referred as biotic zones) on long-term livestock disturbance gradients in the northern Chihuahuan Desert, New Mexico. We estimated abundance of annuals in 0.5-m2 quadrats placed at 30-m intervals on 10 livestock disturbance gradients originating at water points. Tansy mustard, Descurainia pinnata, was abundant in severely disturbed areas and also in areas that are known to have high soil nitrogen content. Amaranthus palmeri was abundant in half of the transects in the zones nearest the water points. The relationships of annual-plant abundance and species richness with distance from water points and with perennial-plant cover were not significant (R2 \< 0.1). The number of boundaries and sizes of zones varied with distance from water points, with seasons, and with duration of grazing. The first biotic zone (most severely impacted by cattle) ranged from 75 to 795 m radius for winter{\textendash}spring annuals and from 165 to 1065 m radius for the summer annuals. Variability in the number and size of biotic zones along grazing gradients was spatially correlated with the frequency and intensity of disturbance, with landscape position, and with patchiness of soil features. There were fewer and larger zones of summer annuals than of winter{\textendash}spring annuals. Boundary analysis of livestock disturbance gradients provided a method with replication for assessing the impact of long-term livestock grazing on annual-plant communities. Livestock create nutrient-rich patches near water points by mixing dung with soil by hoof action. These nutrient-rich patches support species of annuals that are rare or absent in areas where soils are subjected to low-intensity disturbance.

}, keywords = {boundary locations, Chihuahan Desert, desert plant communities, livestock grazing, multivariate analysis, semivariogram}, doi = {10.2307/2641331 }, url = {/files/bibliography/674.pdf}, author = {M. S. Nash and Walter G. Whitford and A.G. de Soyza and Justin Van Zee and Kris Havstad} } @conference {51178, title = {Landscape-scale processes and sensitivity of Chihuahuan Desert ecosystems to climate change}, booktitle = {5th World Congress, International Association for Landscape Ecology}, volume = {II (L-Z)}, year = {1999}, month = {July 29-August 3}, pages = {122}, address = {Snowmass Village, CO}, abstract = {

Our objective was to predict the response of Chihuahuan desert landscapes to climate change using a multiscale approach that includes vegetation-soil feedbacks, seed source and seed dispersal across the landscape. We used vegetation, soils, and climate maps for the Sevilleta National Wildlife Refuge LTER site (SNWR) in central New Mexico as input parameters in a spatially explicit, individual, plant-based simulation model (ECOTONE). The model incorporates feedbacks among vegetation and soil properties and processes that are important to perennial grass establishment and survival. We used the model to predict the locations most likely to shift from shrub- to grass-dominated vegetation due to changes in climate. Our results showed an increase in perennial grass cover throughout the SNWR. Sensitivity of shrub-dominated locations was dependent upon soil texture and distance to the nearest perennial grass seed source. Feedbacks between changes in species composition and soil organic matter modified the rate of change in dominant species. Our results demonstrate the importance of landscape-scale processes and vegetation-soil feedbacks to shifts in vegetation at ecotones.

}, author = {Debra C. Peters and Jeffrey E. Herrick} } @article {51204, title = {Laser-induced fluorescence (LIF) spectra of herbaceous and woody pre- and post-digested plant material}, journal = {Animal Feed Science Technology}, volume = {70}, number = {4}, year = {1998}, month = {March 15, 1998}, pages = {315-337}, abstract = {

Filtrate from pre- and post-digested plant material was exposed to 355-nm pulsed laser light and the subsequent laser-induced fluorescence (LIF) was recorded. Similarities and differences among spectra from 20 materials are discussed. Each material was replicated once, dried, ground, and exposed to chloroform (CHC13) for 24 h. The material represented aged (1 to 18 years old) plants from different herbaceous (grasses and forbs) and woody plant life forms. Mean peak fluorescence recorded among materials differed (P \< 0.0001) in both wavelength and peak amplitude (counts) across the spectral range (387 to 788 nm). Peak fluorescence was evaluated within each of three arbitrary color categories, blue near 455 nm and red near 674 nm, while only 16 of the materials produced a green peak near 528 nm. In general, the blue and green fluorescence peaks were broad while the red peak was narrow. Mean peak counts were largest in the red range. Varying amounts of laser beam absorption occurred among the materials evaluated due to different concentrations of filtrate and different absorption efficiencies; therefore, amplitude data (counts) were not used to determine statistical differences among materials. To overcome difficulties attributed to the raw count data, red/blue, red/green and blue/green count ratios within replicates were calculated. Using all three count ratios in a multivariate analysis of variance, the 16 materials could be separated into nine different (P\<0.05) material groupings. The LIF technique may provide a reliable means to separate ground pre- and post-digested plant materials following further research into determining what fluorophores are producing the spectral signatures and how sample preparation affect peak wavelengths.

}, keywords = {botanical composition, fecal analysis, laser-induced fluorescence, plants}, doi = {10.1016/S0377-8401(97)00088-6}, url = {/files/bibliography/604.pdf}, author = {D.M. Anderson and E.L. Fredrickson and Nachman, P. and Richard E. Estell and Kris Havstad and L. W. Murray} } @conference {51208, title = {Lagtimes in shifts of ecosystem boundaries in response to climate change: Importance of plant recruitment and soil development constraints}, booktitle = {83rd Annual Meeting, Ecological Society of America}, volume = {79}, year = {1998}, month = {1998}, pages = {45}, abstract = {Ecosystem boundaries and geographic distributions of species are predicted to change in response to directional changes in climate. The ability of a species to shift its geographic distribution depends upon processes associated with the recruitment, growth, and mortality of plants. Because these processes are nonlinearly related to climate and are also affected by soil processes, lag times in responses may result. Recent climate change simulation analyses predict an expansion of Chihuahuan desert grasslands and a reduction of shrublands in the southwestern U.S. Our objective was to evaluate the importance of plant life history traits and soil development processes to responses of important species in these ecosystems. We used a spatially-interactive gap dynamics model to predict responses for three conditions of initial soil development, from organic matter-rich soils to highly degraded soils. Predicted response times ranged from decades to millenia, and increased as soil development state decreased. Plant life history traits were the most important constraint on soils with high organic matter content. Although directional climate change may shift species distributions, these shifts will not occur rapidly or uniformly across a landscape or region, and will depend upon interactions between plant and soil processes.}, author = {D.P. Coffin and Jeffrey E. Herrick} } @proceedings {51275, title = {Light reflectance characteristics and video remote sensing of two range sites on the Jornada Experimental Range}, year = {1997}, month = {April 29-May 1, }, pages = {485-495}, address = {Welasco, TX}, abstract = {

The Jornada Experimental Range in southern New Mexico is the site of a long-term ecological research program to investigate the processes leading to desertification. This paper describes the light reflectance characteristics of dominant plant species and soil on two study sites (desert grassland and mesquite dune sites) on the Jornada and evaluates airborne color-infrared video imagery for distinguishing among vegetation types and soil of the two sites. Ground reflectance measurements showed significant differences among major plant species and soil at both sites. At the desert grassland site, black grama [Bouteloua eripoda (Torr.) Torr.] had lower near-infrared reflectance than the other plant species and soil. Honey mesquite [Prosopis glandulosa L. var. torreyana (L. Benson) M. C. Johnston] had lower reflectance than the other plant species and soil at the mesquite dune site. Qualitative analyses of the video imagery showed that black grama and two additional species could be distinguished on the desert grassland site. Honey mesquite and broom snakeweed [Gutierrezia sarothrae (Pursh.) Britt. and Rushy] could be distinguished on the mesquite dune site. These results showed that remote sensing techniques can be useful to distinguish desert vegetation and soil.

}, url = {/files/bibliography/580.pdf}, author = {J. Everitt and Alaniz, M.A. and Davis, M.R. and D.E. Escobar and Kris Havstad and Jerry Ritchie} } @article {51330, title = {Low-cost seeding practices for restoring desert environments (New Mexico)}, journal = {Restoration and Management Notes}, volume = {14}, year = {1996}, month = {1996}, pages = {72-73}, abstract = {

Over the past 120 years, the grasslands of the northern Chihuahuan desert have been converted to shrublands dominate by species such as mesquite (Prosopis spp.). Unfortunately, attemptsto restore these grasslands have often been unsuccessful despite substantial expenditures of money, labor, and fossil fuels. At the Jornada Experimental Range, we have recently begun to test low-input restoration technologies in an attempt to remedy this situation. One aspect of this program focuses on the use of both water and animals to deposit viable seeds into favorable micro-sites.

}, url = {/files/bibliography/480.pdf}, author = {E.L. Fredrickson and J.R. Barrow and Jeffrey E. Herrick and Kris Havstad and Longland, B.} } @article {51339, title = {Legacy of Charles Travis Turney: The Jornada Experimental Range}, journal = {Archeological Society of New Mexico Annual Volumes}, volume = {22}, year = {1996}, month = {1996}, pages = {77-92}, abstract = {The Jornada Experimental Range (JER) in south-central New Mexico has served as a field research laboratory since its establishment in 1912. The varied scientific activities on the range throughout this century have led to important discoveries about desert ecosystems that have been the basis for principles of land management that have application around the globe. This region is probably the most extensively studied desert on earth, and on-site research activities continue to flourish as we approach the next millennium. From microscopic-scale studies of soil microorganisms to synoptic-scale assessments of vegetation patterns detected from satellite-based sensors, JER is addressing a multitude of research needs relevant to natural resource management issues. One phenomenon that we have continually observed in our studies over the years is that small events can have cascading effects on ecosystem structures and functions. A period of drought, an innocuous ntroduction of an alien species, unmanaged grazing, or dispersal of seed into a new area are examples of events that can have far-reaching effects in subsequent decades. Like these biological events, the inception of JER was based on a relatively small event that has then cascaded into the legacy of scientific discovery that is the Jornada range today. In 1904, Harvey Ringer, a man not particularly interested in the cattle businsess, sold 16 ha of land in the south-central portion of the 3,000 km2 Jornada Plain to a man from Texas, Mr. C. T. Turney.}, url = {/files/bibliography/484.pdf}, author = {Kris Havstad} } @proceedings {51336, title = {Linking rangeland science to western rangeland issues}, year = {1996}, month = {March 11-14, 199}, pages = {Abstract 10}, address = {Albuquerque, NM}, url = {/files/bibliography/485.pdf}, author = {Kris Havstad} } @article {51377, title = {Lateral root development and hydraulic conductance in four populatoins of Gutierrezia sarothrae}, journal = {Environmental and Experimental Botany}, volume = {36}, number = {2}, year = {1996}, note = {//USDA//NONE//}, month = {1996}, pages = {157-165}, abstract = {We hypothesize that drought-avoidance in Gutierrezia sarothrae populations is characterized by well-developed lateral roots. Root growth and hydraulic conductance were studied in four populations of Gutierrezia sarothrae. Seedlings from a Malta, Idaho (ID) seed source had four times higher root/shoot ration, but only 17\% hydraulic conductance of those from Tahoka, Texas (TA) seed source. Consequently, transpiration surface area of the ID seedlings was 17\% that of the TA seedlings. There was no difference in total root length between the seedlings, but hydraulic conductance per unit root length was 3.8 fold great in the TA seedlings, which was accompanied by a lower specific lateral root length, thus greater lateral root diameters. A parallel experiment with adult plants from New Mexico (NM) and Plains, Texas (PL) and the above two populations showed that whole-plant hydraulic conductance was ordered as NM>TA=PL>ID. The NM and TA populations had lower specific lateral root length, thus larger-diameter laterals, than the ID population. The NM population had similar transpiration surface area and total root length as that of the TA population, but a greater lateral root biomass than the latter. Because of higher hydraulic conductance in the NM population, its xylem water potential declined more slowly than that of the Texas and Idaho populations as soil moisture deficit developed. Therefore, the NM population was able to maintain a higher stem conductance during drought, which was associated with its higher whole-plant hydraulic conductance and greater carbon partitioning in the stems. The drought avoidance mechanism in the NM plants was characterized by an efficient water transport system due to greater lateral root biomass and more stems per unit leaf area. The high root/shoot ratio in desert populations (NM and ID) as compared with that of the semiarid rangeland populations (TA and PL) does not ensure more effective water acquisition. Rather, root morphological modifications such as accelerated secondary thickening of lateral roots may play an important role in enhancing water-acquisition capability of the root systems of Gutierrezia sarothrae.}, keywords = {article, articles, drought tolerance, Gutierrezia, Gutierrezia, drought tolerance, Gutierrezia, hydraulic conductance, Gutierrezia, root growth, Gutierrezia, root:shoot ratios, Gutierrezia,xylem water potential, hydraulic architecture, Gutierrezia, journal, journals, root systems, Gutierrezia, water potential, Gutierrezia}, author = {Wan, Changgui and R. E. Sosebee and McMichael, Bobby L.} } @article {51059, title = {Low temperature SEM of precipitated and metamorphosed snow crystals collected and transported from remote sites}, journal = {Hitachi Instrument News}, volume = {37}, year = {1996}, month = {06/1996}, pages = {11-24}, abstract = {

Procedures were developed to sample, store, ship and process precipitated and metamorphosed snow crystals, collectively known as "snowflakes," from remote sites to a laboratory where they could be observed and photographed using low temperature scanning electron microscopy (LTSEM). Snow samples were collected during 1994-96 from West Virginia, Colorado, and Alaska and sent to Beltsville, MD, for observation. The samples consisted of freshly precipitated snowflakes and snow collected from pits excavated in winter snowfields measuring up to 1.5m in depth. The snow crystals were mounted on copper plates, plunged into lN2, transferred to a storage dewar and shipped to the laboratory. Observations easily recorded in stereo format (three dimension) revealed detailed surface features on the precipitated crystals consisting of rime, graupel and skeletal features. Samples from snowpacks preserved the metamorphosed crystals which had unique structural features and bonding patterns resulting from temperature and vapor pressure gradients. In late spring, the surface of a snowpack in an alpine region exhibited a reddish hue. Undisturbed surfaces from these snowpacks were sampled to observe the snow crystals and the organisms responsible for the coloration. Etching the surface of samples from these sites exposed the presence of numerous cells believed to be algae. Study results indicate LTSEM can be used to provide detailed information about the surface features of precipitated and metamorphosed snow crystals sampled at remote locations. The technique can also be used to increase understanding of ecology snow. The results have application to research activities attempting to forecast the water quantity in winter snowpack and the amount reaching reservoirs and available for agriculture and hydroelectric power.

}, url = {files/bibliography/Rango1996-01.pdf}, author = {W.P. Wergin and A. Rango and E. R. Erbe and Murphy, C.A.} } @mastersthesis {51509, title = {Longterm mesquite control influences on Chihuahuan desert vegetation}, year = {1993}, note = {//??//NONE//}, month = {1993}, pages = {71}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {brush control,Prosopis, dissertation, dissertations, Prosopis,brush control, theses, thesis}, author = {Warren, Alan Alden} } @article {51516, title = {A long-term positive effect of kangaroo rats (Dipodomys spectabilis) on creosotebushes (Larrea tridentata)}, journal = {Journal of Arid Environments}, volume = {22}, year = {1992}, note = {//OTHER//NONE//}, month = {1992}, pages = {375-386}, abstract = {

Several studies have shown the effects of the mounds of the banner-tailed kangaroo rat (Dipodomys spectabilis Merriam) on desert annuals. There can be effects on density, biomass and composition of the herbaceous assemblage (Moroka et al., 1982; Mun \& Whitford, 1989). As a result of a long-term study of a site in south-eastern Arizona, we observed a positive effect of these mounds on the growth, flowering and fruiting, and survival of creosotebush, which is the dominant woody perennial of the community. This effect became obvious at this site long after the kangaroo rats disapppeared from the system, probably as a result of invasion of creosotebushes and other shrubby vegetaion into what was previously a desert grassland system. Whereas creosotebushes had a negative effect on the kangaroo rat population, the mounds created by these rodents have had a residual positive effect on the creosotebushes. A number of measurements were made to examine the nature of this unusual, if not unique, relationship, and to provide some basis for speculation as to the cause(s) of the positive effect.

}, keywords = {article, articles, Dipodomys mound,annual plants, journal, journals, kangaroo rat, SEE , Larrea,phenology, Larrea,rodent mound effects, rodent,Dipodomys}, doi = {10.1016/S0140-1963(18)30580-9}, url = {files/bibliography/92-JrnArdEnvnmnts-Whitford.pdf}, author = {Chew, Robert M. and Walter G. Whitford} } @article {51537, title = {Litter decomposition in Chihuahuan Desert playa}, journal = {The American Midland Naturalist}, volume = {128}, year = {1992}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1992}, pages = {84-94}, abstract = {

Mass loss rates were compared for several types of litter in a flooded desert ephemeral playa. Most nonwoody types of organic matter, including black grama grass, creosotebush leaves and rabbit feces decomposed rapidly. Creosotebush twigs and wood decomposed slowly. About 25\% of the mass was lost due to abiotic leaching. Predator exclusion significantly increased decomposition of creosotebush leaves, but reduced mass loss rate of creosotebush twigs and black grama grass. Decomposition rates were within the range of those found in lakes, and much lower than rates typical of streams. Our data suggest that organisms have little effect on mass loss of debris transported into a desert playa.

}, keywords = {article, articles, decomposition,playa litter, journal, journals, litter, decomposition, playa,litter decomposition}, doi = {10.2307/2426416 }, url = {files/bibliography/JRN00159.pdf}, author = {William P. MacKay and J. C. Zak and Walter G. Whitford} } @article {51599, title = {The Las Cruces trench site: characterization, experimental results, and one-dimensional flow predictions}, journal = {Water Resources Research}, volume = {27}, number = {10}, year = {1991}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1991}, pages = {2695-2705}, abstract = {

A comprehensive field trench study was conducted in a semiarid area of southern New Mexico to provide data to test deterministic and stochastic models of vadose zone flow and transport.... Comparisons between the one-dimensional infiltration model predictions and field observations show that the use of the layered soil model rather than the uniform soil model does not consistently improve the accuracy of the predictions for this particular field application. This result illustrates that increasing the spatial resolution of the deterministic characterization of the site in the vertical direction does not always improve the model predications. Uncertainties due to horizontal spatial variability and due to other difficulties associated with experimental characterization appear to be more significant.

}, keywords = {article, articles, journal, journals, model, infiltration, rainfall simulation, infiltration, trench study}, doi = {10.1029/91WR01537}, url = {files/bibliography/JRN00144.pdf}, author = {Peter J. Wierenga and Hills, R. G. and D. B. Hudson} } @book {51651, title = {Long-term ecological research in the United States: a network of research sites}, year = {1989}, note = {//NMSU//LTER//}, month = {1989}, publisher = {LTER Network Office, College of Forestry Resources AR-10, University of Washington}, organization = {LTER Network Office, College of Forestry Resources AR-10, University of Washington}, edition = {5th edition, revised}, address = {Seattle, WA}, abstract = {

Long-Term Ecological Research (L TER) is a pilot program supported by the National Science Foundation{\textquoteright}s Division of Biotic Systems and Resources (BSR). The program was developed from 1976 to 1979 when the first open competition for support was announced. L TER acknowledges:
1.That there are ecological phenomena that occur on time scales of decades or cen-
turies; periods of time not normally investigated with research support from NSF.
2. That many ecological experiments are performed without sufficient knowledge of the year-to-year variability in the system. Interpretation is, therefore, difficult. This is especially true when the system in which the experiment is performed is not at equilibrium.
3.That long-term trends in natural ecosystems were not being systematically monitored. Unidirectional changes that were observed could not be distinguished from cyclic changes on long time scales.
4.That a coordinated network of sites was not available to facilitate comparative experiments. Furthermore, data management was not being coordinated between research sites. Therefore, comparative analyses could not be performed and theoretical constructs could not be conveniently tested.
5. That examples of natural ecosystems were being converted to uses incompatible with ecological research.
6.That advances in ecological research have often treated phenomena at higher or lower levels of organization as insignificant or constant or by oversimplification. This problem can be alleviated by performing intensive investigations at single sites, leading to an accumulation of overlapping information. Through time, site specific research will generate increasingly valuable data sets, revealing pattern and control at several levels of ecosystem organization.
Initial convergence of the L TER effort was encouraged by requiring that sites ad-dress research efforts in five core areas. These were (1) pattern and control of primary production; (2) spatial and temporal distribution of populations selected to represent trophic structure; (3) pattern and control of organic matter accumulation in surface layers and sediments; (4) pattern of inorganic inputs and movements of nutrients through soils, groundwater, and surface waters; and (5) pattern and frequency of disturbance to the research site.
The institutions serving in support of L TER sites are committed to encourage col-laborative research by scientists at other institutions. L TER sites should be considered regional or national research facilities. If you are interested in using these facilities, please contact directly the sites identified in this brochure.

}, keywords = {book, books, chapter, chapters, LTER,site descriptions, report, reports, review, LTER site descriptions}, url = {files/bibliography/JRN00100.pdf}, author = {Brenneman, Judy} } @book {51696, title = {The long-term effects of habitat modification on a desert rodent community}, series = {Patterns in the Structure of Mammalian Communities}, volume = {No. 28}, year = {1989}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//ProCite field[6]: In}, month = {1989}, pages = {33-43}, publisher = {Special Publications Museum, Texas Tech University}, organization = {Special Publications Museum, Texas Tech University}, address = {Lubbock, Texas}, abstract = {

Data are presented from the results of a 14-year study of changes in composition of a desert rodent community following habitat perturbation. We studied rodent populations in an area where herbicide treatment reduced shrub cover from 19.7 percent to less than one percent and increased grass cover from 1.3 percent to 22.3 percent. In the first two years following the perturbation, Dipodomys ordii was the most abundant species in the shrub habitats. From 1976 through 1984, the rodent community in both areas was dominated by D. merriami and D. ordii was absent or occurred at low densities in both habitats. Species richness was highest in 1976 and 1985 following successive \"wet\" seasons. In 1985, following three above average wet seasons, D. ordii once again became the most abundant rodent in the grass habitat. Neotoma micropus increased in abundance with increased grass cover. These results suggest interspecific competition between D. ordii and D. merriami during average to dry periods of limited resources. Successive wet seasons allow D. ordii, which has higher fecundity, to increase because resources are not limiting during such periods. Successive wet seasons result in increased species richness due to immigration of opportunistic species like Sigmodon hispidus and Reithrodontomys megalotis.

}, keywords = {book, books, chapter, chapters, Dipodomys,habitat modification, Neotoma,habitat modification, Reithrodontomys,habitat modification, report, reports, rodent community,habitat modification, rodent,habitat modification, Sigmodon,habitat modification}, isbn = {978-0896721739}, url = {files/bibliography/89-PatStrutofMamComm-Whitford.pdf}, author = {Walter G. Whitford and Yosef Steinberger}, editor = {Morris, D. W. and Abramsky, Z. and Fox, B. J. and Michael R. Willig} } @article {51784, title = {Locating discontinuities along ecological gradients}, journal = {Ecology}, volume = {68}, number = {2}, year = {1987}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1987}, pages = {448-450}, abstract = {

Cost-efficient ecological and natural surveys need: (1) flexible, logistically simple, and statistically sound sampling methods, and (2) sensitive, computationally simple, and ecologically robust data analysis methods. "Gradsects" (gradient-oriented transects) have recently been shown to be a more efficient sampling method than random sampling using nongradient-oriented transects, especially when surveying large, biologically diverse areas (Gillison and Brewer 1985). If biotic (e.g., vegetation) sampling is oriented along a defined environmental gradient, and the purpose is classification, then simple, efficient analysis techniques are needed. This note briefly reviews appropriate analysis techniques in order to identify ecotones or boundaries along gradsects.

}, keywords = {article, articles, ecological gradients, journal, journals, method, gradient-oriented transects, method, locating ecotones, method, sliding window, resource surveys, transect, ecotones}, doi = {10.2307/1939277 }, url = {files/bibliography/JRN00056.pdf}, author = {J. Ludwig and Joe M. Cornelius} } @proceedings {51872, title = {Livestock behavior--The neglected link in understanding the plant-animal interface}, year = {1985}, month = {1985}, pages = {116-148}, address = {Morrilton, AK}, abstract = {Mixed species grazing of cattle and sheep on rangeland has been advocated for over 40 years as ecologically and economically sound. Past research has concentrated mainly on the nutrition of the grazing animal. To improve the efficiency of animal production into the 21st century, understanding the behavior of grazing animals will be essential. Behavior of free-ranging animals is dynamic with respect to time and space, in addition to being influenced by both abiotic and biotic factors. The complexity in investigating this plant-animal system has led to the adaptation and/or development of many mechanical and electronic devices. With integration of several disciplines, an interdisciplinary team approach should provide major advances in understanding and developing sound grazing management practices. Initial results from a mixed-species grazing study involving nutrition and behavior began on the Jornada Experimental Range in 1984. Preliminary data suggest that cattle and sheep diets are complementary and that both animal species have unique temporal and spatial behavior patterns.}, keywords = {grazing study, Jornada Experimental Range, livestock behavior, plant-animal system}, url = {/files/bibliography/274.pdf}, author = {D.M. Anderson and J. N. Smith and Clarence V. Hulet} } @conference {51871, title = {Liveweight, electronics and range cattle production}, booktitle = {38th Annual Meeting, Society for Range Management}, year = {1985}, month = {1985}, pages = {No. 152}, abstract = {With the use of mechanical and electronic equipment, it was possible, by exploiting an animal{\textquoteright}s need for water, to eliminate the stress often associated with the frequent weighing of individual cows while automating the entire process. It was then possible to evaluate how the frequency of obtaining individual cattle liveweights would influence the liveweight profile of a single herd of cows grazing arid southern New Mexico rangeland between July 1980 and February 1983. Approximately every 28 days, individual cows were weighed using conventional procedures. Between the 28 day weighings, each cow was automatically weighed before being allowed to drink water each time it entered a corral which contained drinking water. The liveweight profile obtained from the two weighing procedures differed (P<.10). If a cow was assumed to be biologically the same over seven consecutive days, it was possible to detect a change (P <.10) in her liveweight profile on the eighth consecutive day after automatic weighing began. Thus, the cause and effect of events involving a change in liveweight, such as parturition, were monitored and liveweight data became a tool rather than a product of management.}, keywords = {electronics, liveweight, production, range cattle, stress}, author = {D.M. Anderson and Weeks, D.L.} } @article {51930, title = {Life styles of desert litter-dwelling microarthropods: a reappraisal based on the reproductive behavior of Cryptostigmatid mites}, journal = {Suid-Afrikaanse Tydskrif vir Wetenskap}, volume = {80}, year = {1984}, note = {//NMSU//NONE, LTER//}, month = {1984}, pages = {163-169}, abstract = {

Studies in a series of Chihuahuan Desert litter and soil habitats confirmed that reproductive activity was most pronounced following the major rainfall, as in the Mojave Desert. Immediately after the summer rains, evidence was found of considerable breeding activity in more than 60\% of the oribatid species studied in the former desert.

}, keywords = {article, articles, Cryptostigmatid mites, journal, journals, litter, microarthropods, microarthropod,life history, microarthropod,litter, mite, reproduction, mite,Cryptostigmatid, rainfall simulation, microarthropod response}, url = {files/bibliography/JRN00014.pdf}, author = {J. A. Wallwork and B. W. Kamill and Walter G. Whitford} } @article {52050, title = {Litter decomposition in the desert}, journal = {BioScience}, volume = {31}, year = {1981}, note = {//NMSU//NONE//}, month = {1981}, pages = {145-146}, abstract = {

Since significant quantities of plant litter are buried by wind and water in this desert, we designed studies to address the following questions: What are the relative contributions of bacteria, fungi, and microarthropods to litter decomposition? Is there a pattern of microarthropods succession related to the stage of litter decomposition? What are the differences in buried and surface litter decomposition? The initial stages of buried litter decomposition appears to be via bacteria, which are grazed upon by nematodes. Removal of the nematode predator apparently allowed nematodes to overgraze the bacteria, reducing their population size and reducing decomposition. Without predators, grazers appear to be detrimental to decomposition, as has been suggested by Hanlon and Anderson (1979). Thus, in desert ecosystems, microarthropods affect litter decomposition by a heretofore undescribed mode: preying on free-living nematodes.

}, keywords = {article, articles, enchytraeids, fungi, fungicide, Benomyl, fungicide, Dexon, insecticide, insecticide, Chlordane, invertebrate,enchytraids, journal, journals, Larrea, litter decomposition, litter decomposition,microarthropods, microarthropod, litter decomposition, mite, mite, tydeid, nematode, predation, microarthropods, psocoptera, soil microarthropods, termite, litter decomposition}, doi = {10.2307/1308261}, url = {files/bibliography/81-BioScience-Whitford.pdf}, author = {Perseu F. Santos and Walter G. Whitford} } @article {52082, title = {Location of food source by subterranean termites}, journal = {Environmental Entomology}, volume = {9}, number = {5}, year = {1980}, note = {//NMSU//NONE//}, month = {1980}, pages = {645-648}, abstract = {

Chihuahuan desert subterranean termites, Gnathamitermes tubiformans (Buckley) and Amitermes wheelerii (Desneux) readily located surface foods but failed to utilize buried foods of the same type. The termites attacked both natural cowdung pats and artificial (polyurethane) cowdung pats at the same rate as estimated by holes chewed through plastic film barriers placed between the soil and both kinds of pats. There was smaller diel excursion of temperatures in the upper 20 cm of soil under dungpats than in the soil not under dung. We suggest that desert subterranean termites locate relatively large size surface foods such as cattle dung and Yucca sp. logs by sensing the thermal shadows cast by such items.

}, keywords = {Amitermes,decomposition, article, articles, decomposition,termite, Gnathamitermes,decomposition, journal, journals, termite, Amitermes, termite, decomposition, termite, Gnathamitermes, termite,food sources}, doi = {10.1093/ee/9.5.645}, url = {files/bibliography/80-EnvirEnt-Whitford.pdf}, author = {George Ettershank and Jennifer Ettershank and Walter G. Whitford} } @article {52368, title = {Liquid and dry supplements for wintering range beef calves}, year = {1971}, month = {1971}, pages = {8 }, address = {Las Cruces}, abstract = {The nutritive value of range plants decreases as they mature. When these plants are dormant, they are often deficient in certain nutrients, particularly protein and phosphorus. These deficiencies have been shown by many studies, including those at New Mexico State University. To correct these deficiencies during the winter, supplemental nutrients may be provided in many forms, the most common being meals, pellets and blocks. A relatively new practice is the use of liquid supplements. Such supplements have a liquid base, usually molasses, to which other ingredients are added. The most common addition is nonprotein nitrogen, such as urea, next most common is phosphorus and others are vitamins, minerals and antibiotics. Most liquid supplements are used in feedlot rations. Animals on pasture or range may also be offered liquid supplement free-choice, either ad libitum (at will) or restricted. With ad lib feeding, the supplement is placed in an open container with animal intake restricted only by formula modification. With restricted feeding, intake is controlled by mechanical feeders. The feeder is usually a covered container with one or more wheels extending down through the cover; the wheels turn as they are licked by the animals and a fresh layer of liquid is picked up with each turn. Decisions about supplements to feed to grazing cattle during the winter season should be based on what nutrients are lacking in the forage available for grazing. Many forms and formulations of supplements may be purchased and the increased availability of liquidsupplements has raised many questions concerning their nutritive value. To answer these questions, the NMSU Agricultural Experimental Station compared weight gains and feed costs of range beef calves fed liquid and dry supplements. Liquid supplements were compared to dry supplements in four experiments. All comparisons were with beef calves weaned in October and allowed to graze in native grass pastures. The pastures contained adequate quantities of dry grass, although the number of acres required per head varied considerably.}, keywords = {cattle, government publication, range plants, supplemental nutrients, winter grazing}, url = {/files/bibliography/131.pdf}, author = {Nelson, A.B. and Neumann, A.L. and C.H. Herbel and Yarbrough, C.C. and E. Parker and Whittenburg, J.} } @proceedings {52399, title = {Life history and population dynamics of the black-tailed jackrabbit (Lepus californicus) in New Mexico}, year = {1970}, note = {//USDA//US-IBP ??//ProCite field[6]: In}, month = {1970}, pages = {213-217}, publisher = {Colorado State University}, abstract = {The results of a growth rate study by Haskell and Reynolds (1947) are shown in Figure 1. California rabbits born in captivity were used for the study. Birth weights were approximately 110 gm, and adults grew to an average of about 2300 gm. These weights correspond well with the results from a Utah study (Gross and Stoddart).}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, Lepus,life history, Lepus,population dynamics, proceeding, proceedings, rabbit,Lepus,life history, rabbit,Lepus,population dynamics}, author = {Stoddart, L. Charles}, editor = {R. G. Wright and Dyne, G. M. (eds.)} } @article {52442, title = {Life-history characteristics of the creosotebush, Larrea tridentata}, year = {1968}, note = {//??//NONE//}, month = {1968}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, abstract = {

Creosotebush (Larrea tridentata (DC.) Coville) aggressively invades desert plains grassland in Arizona, New Mexico, and western Texas. Gardner (10) recorded invasion of grassland along the Rio Grande Valley in southern New Mexico and pointed out that it takes the form of frontal advances along the margins of the larger creosotebush communities and of a single plants and then small outlier stands at varying distances from the main bodies of the larger communities. Yang (21) recorded invasions of grassland on upland plains adjacent to the Rio Grande Valley. Buffington and Herbel (2), using 1858 General Land Office survey records and recent observations, reported increase of creosotebush on the Jornada Experimental Range in southern New Mexico from 644 acres of moderately invaded range (creosotebush comprising 15 to 55 percent of the perennial vegetation) in 1858 to 12,388 acres of heavily invaded range (55 to 100 percent of vegetation) in 1963.

}, keywords = {book, books, chapter, chapters, Larrea,life history, report, reports}, isbn = {Bulletin 526}, url = {/files/bibliography/526.pdf}, author = {Valentine, K. A. and J. B. Gerard} } @article {JRN55322, title = {Long-Term Agroecosystem Research Network Regions, 2018 version}, publisher = {Ag Data Commons}, abstract = {The Long-Term Agroecosystem Research Network, consisting of 18+ research locations, is conducting research on the sustainable intensification of agroecosystems. To enable coordinated network level research, a spatial framework is required to facilitate analysis. However, no suitable spatial framework currently exists to meet the needs for the LTAR Network. To develop a framework for analysis the LTAR Network initiated the Regionalization Project. Goals also included providing a standardized spatial footprint for LTAR cross-site investigations, estimating the confidence with which results from research plots and fields could reasonably be extrapolated to "represented regions", informing decisions about where additional research sites should be prioritized and facilitating public outreach of the LTAR Network. To address these goals a workshop was held in 2018 resulting in the production of three sets of regional boundaries in a geographic information system (GIS). These GIS datasets are intended to be used for mapping the network and for summarizing spatial data relevant to domains of sustainable intensification corresponding with agricultural production, environmental impact, and rural prosperity. This resulted in a geodatabase of three new maps describing regional boundaries for the LTAR Network titled "Long-Term Agroecosystem Research Network regions, 2018 version", archived in the USDA National Agricultural Library{\textquoteright}s Ag Data Commons repository.}, doi = {10.15482/USDA.ADC/1520632}, author = {A. W. Coffin and Sclater, V. and Chandra D. Holifield Collins and D W Archer and G. Armendariz and Dan Arthur and D.J. Augustine and Claire Baffaut and A. R. Bean and Dawn M. Browning and B. R. Carlson and Patrick E. Clark and J. D. Derner and David Huggins and D. E. James and N. E. Kaplan and K.W. King and Peter J. A. Kleinman and Ponce Campos and G. E. Porensky and L. M. Robertson and P. Sadler and Douglas Smith and S. Spiegal and Jean Steiner and Timothy Strickland and Bruce Vandenberg and Steven Scott Van Vactor and Brian Wienhold and Yasarer, L.M.} }