@conference {JRN55435, title = {Calculation of daily distance walked by grazing cattle using real-time activity and position data collected by LORA-WAN sensors}, booktitle = {2nd U.S. Precision Livestock Farming Conference}, year = {2023}, month = {12/12/2022}, abstract = {LoRa-WAN sensors were used to compare methods for determining walking distances by grazing cattle in near real-time. The accuracy of relying on a global positioning system (GPS) alone or in combination with motion data derived from triaxial accelerometers was compared using stationary control trackers (Control) placed in fixed field locations (n=6) vs. trackers (Test) mounted on cows (n=6) grazing on pasture at the New Mexico State University{\textquoteright}s Clayton Livestock Research Center. Trackers communicated motion data at 1-minute intervals and GPS positions at 15-minute intervals for seven days. Daily distance walked was determined using: 1) raw GPS data (RawDist), 2) data with erroneous GPS locations removed (CorrDist), or 3) data with erroneous GPS locations removed and with GPS data associated with the static state excluded (CorrActDist). Distances were analyzed via one-way ANOVA to compare Control vs. Test deployment effects. No difference (P=0.43) in walking distance was detected between Control vs. Test for RawDist. However, distances calculated for CorrDist differed (P<0.01) between the two tracker deployments. Due to the random error of GPS measurements, CorrDist for stationary devices differed (P=0.01) from zero. The walking distance calculated by CorrActDist differed (P<0.01) between Control vs. Test trackers, with distances for Control trackers not differing (P=0.44) from zero. The fusion of GPS and accelerometer data was a more suitable method for calculating walking distance by grazing cattle. This result may highlight the value of combining more than one source of independent sensor data in Precision Livestock Farming applications.}, keywords = {compare methods, grazing cattle, LoRa-WAN sensors, Real-time, walking distances}, author = {Nyamuryekung{\textquoteright}e, Shelemia and Duff, Glenn and Utsumi, Santiago. A. and Estell, Rick E. and McIntosh, Matthew. M. and M. Funk and Andrew Cox and Huiping Cao and H. Chen and Sheri Spiegal and Perea, A. and Rahman, A.F. and Cibils, Andres F.} } @article {JRN55414, title = {Cross-Site comparisons of dryland ecosystem response to climate change in the US Long-Term Ecological Research Network}, journal = {BioScience}, volume = {72}, year = {2022}, month = {8/16/2022}, pages = {889-907}, abstract = {Long-term observations and experiments in diverse drylands reveal how ecosystems and services are responding to climate change. To develop generalities about climate change impacts at dryland sites, we compared broadscale patterns in climate and synthesized primary production responses among the eight terrestrial, nonforested sites of the United States Long-Term Ecological Research (US LTER) Network located in temperate (Southwest and Midwest) and polar (Arctic and Antarctic) regions. All sites experienced warming in recent decades, whereas drought varied regionally with multidecadal phases. Multiple years of wet or dry conditions had larger effects than single years on primary production. Droughts, floods, and wildfires altered resource availability and restructured plant communities, with greater impacts on primary production than warming alone. During severe regional droughts, air pollution from wildfire and dust events peaked. Studies at US LTER drylands over more than 40 years demonstrate reciprocal links and feedbacks among dryland ecosystems, climate-driven disturbance events, and climate change.}, keywords = {ANPP, climate change, disturbance, drought, LTER, wildfire}, doi = {https://doi.org/10.1093/biosci/biab134}, url = {files/bibliography/22-023.pdf}, author = {Amy R Hudson and Debra P C Peters and John M Blair and Daniel L. Childers and Peter T Doran and Kerrie Geil and Micheal Gooseff and Katherine L Gross and Nick Haddad and Melissa A Pastore and Jennifer A Rudgers and Osvaldo Sala and Eric W Seabloom and Gaius Shaver} } @proceedings {JRN55418, title = {Characterizing dust from National Wind Erosion Research Network sites using isotopic fingerprinting, mineralogy, and major and trace element chemistry}, year = {2022}, month = {12- 9 to14- 2022}, abstract = {The frequency of dust storms is increasing globally yet it is often difficult to determine dust sources in mixed events. Dust events are known to negatively impact human health due to particle size and composition but little is known about the chemistry and mineralogy of major dust sources. The National Wind Erosion Research Network (NWERN) has various sites throughout the western US collecting seasonal dust emission samples to quantify dust fluxes. Our purpose is to use the existing dust samples to characterize the isotopic, chemical, and mineralogical composition of dust from 10 representative NWERN sites that are representative of the network and compare with land use, bedrock geology, and vegetation. Preliminary results show variability in the chemistry across the 10 sites related to differences in surficial geology and other factors. For example, the Holloman AFB site had distinct seasonal changes in dust chemistry with spikes in Na, Mg, Ca, Ni, and Sr during the spring months possibly related to changes in wind direction and inputs from neighboring White Sands National Monument. The Lordsburg Playa site had distinct chemistry relative to other sites with high concentrations of Li, Na, Ca, and Sr due to the prevalence of evaporite minerals. The Morton Mandan site also had distinct chemistry relative to other sites with high concentrations of metals Cr, Fe, Co, and Ni, suggesting anthropogenic inputs. Our dataset has implications for quantifying dust sources across the western US and will be useful for mitigating dust hazards moving forward. }, keywords = {Characterizing dust, chemistry, isotopic fingerprinting, major, mineralogy, National Wind Erosion Research Network, trace element}, author = {Abby Mangum and Gregory Carling and Zachary Aanderud and Diego Fernandez and Stephen Nelson and Kevin Rey and Joshua LeMonte and DeTiare Leifi and Janice Brahney and Nicholas Webb} } @article {JRN55392, title = {The consequences of climate change for dryland biogeochemistry}, journal = {New Phytologist}, year = {2022}, month = {6/15/2022}, abstract = {Drylands, which cover > 40\% of Earth{\textquoteright}s terrestrial surface, are dominant drivers of global biogeochemical cycling and home to more than one third of the global human population. Climate projections predict warming, drought frequency and severity, and evaporative demand will increase in drylands at faster rates than global means. As a consequence of extreme temperatures and high biological dependency on limited water availability, drylands are predicted to be exceptionally sensitive to climate change and, indeed, significant climate impacts are already being observed. However, our understanding and ability to forecast climate change effects on dryland biogeochemistry and ecosystem functions lag behind many mesic systems. To improve our capacity to forecast ecosystem change, we propose focusing on the controls and consequences of two key characteristics affecting dryland biogeochemistry: (1) high spatial and temporal heterogeneity in environmental conditions and (2) generalized resource scarcity. In addition to climate change, drylands are experiencing accelerating land-use change. Building our understanding of dryland biogeochemistry in both intact and disturbed systems will better equip us to address the interacting effects of climate change and landscape degradation. Responding to these challenges will require a diverse, globally distributed and interdisciplinary community of dryland experts united towards better understanding these vast and important ecosystems.}, keywords = {arid lands, global change, islands of fertility, multiple resource limitation, restoration}, doi = {10.1111/nph.18312}, url = {files/bibliography/22-019.pdf}, author = {Brooke B. Osborne and Brandon T Bestelmeyer and Courtney M. Currier and Peter M. Homyak and Heather L. Throop and Kristina Young and Sasha C. Reed} } @article {JRN55344, title = {Classification of daily crop phenology in PhenoCams using deep learning and hidden markov models}, journal = {Remote Sensing}, volume = {14}, year = {2022}, month = {1/9/2022}, chapter = {2}, abstract = {Near-surface cameras, such as those in the PhenoCam network, are a common source of ground truth data in modelling and remote sensing studies. Despite having locations across numerous agricultural sites, few studies have used near-surface cameras to track the unique phenology of croplands. Due to management activities, crops do not have a natural vegetation cycle which many phenological extraction methods are based on. For example, a field may experience abrupt changes due to harvesting and tillage throughout the year. A single camera can also record several different plants due to crop rotations, fallow fields, and cover crops. Current methods to estimate phenology metrics from image time series compress all image information into a relative greenness metric, which discards a large amount of contextual information. This can include the type of crop present, whether snow or water is present on the field, the crop phenology, or whether a field lacking green plants consists of bare soil, fully senesced plants, or plant residue. Here, we developed a modelling workflow to create a daily time series of crop type and phenology, while also accounting for other factors such as obstructed images and snow covered fields. We used a mainstream deep learning image classification model, VGG16. Deep learning classification models do not have a temporal component, so to account for temporal correlation among images, our workflow incorporates a hidden Markov model in the post-processing. The initial image classification model had out of sample F1 scores of 0.83{\textendash}0.85, which improved to 0.86{\textendash}0.91 after all post-processing steps. The resulting time series show the progression of crops from emergence to harvest, and can serve as a daily, local-scale dataset of field states and phenological stages for agricultural research.}, keywords = {crop phenology; PhenoCam; VGG16; hidden Markov model; time series; LTAR}, doi = {10.3390/rs14020286 }, url = {files/bibliography/22-002.pdf}, author = {Shawn D. Taylor and Dawn M. Browning} } @article {JRN55280, title = {A Comparison of Approaches to Regional Land-Use Capability Analysis for Agricultural Land-Planning}, journal = {Land}, volume = {10}, year = {2021}, month = {04/2021}, chapter = {458}, abstract = {: Smallholder agriculture is a major source of income and food for developing nations. With more frequent drought and increasing scarcity of arable land, more accurate land-use planning tools are needed to allocate land resources to support regional agricultural activity. To address this need, we created Land Capability Classification (LCC) system maps using data from two digital soil maps, which were compared with measurements from 1305 field sites in the Dosso region of Niger. Based on these, we developed 250 m gridded maps of LCC values across the region. Across the region, land is severely limited for agricultural use because of low available water-holding capacity (AWC) that limits dry season agricultural potential, especially without irrigation, and requires more frequent irrigation where supplemental water is available. If the AWC limitation is removed in the LCC algorithm (i.e., simulating the use of sufficient irrigation or a much higher and more evenly distributed rainfall), the dominant limitations become less severe and more spatially varied. Finally, we used additional soil fertility data from the field samples to illustrate the value of collecting contemporary data for dynamic soil properties that are critical for crop production, including soil organic carbon, phosphorus and nitrogen.}, keywords = {agricultural, drought, land capability classifications, land degradation, vulnerability}, doi = {https://doi.org/10.3390/land10050458}, url = {files/bibliography/21-014.pdf}, author = {Ippolito, Tara A. and Jeffrey E. Herrick and Dosswa, Eckwe and Garba, Maman and Ouattara, Mamadou and Singh, Upendra and Stewart, Zachary and Prasad, P. V. Vara and Oumarou, Idrissa A. and J. Neff} } @article {JRN55282, title = {Connectivity: insights from the U.S. Long Term Ecological Research Network}, journal = {Ecosphere}, volume = {12}, year = {2021}, month = {May 17, 2021}, pages = {1-30}, abstract = {Ecosystems across the United States are changing in complex and surprising ways. Ongoing demand for critical ecosystem services requires an understanding of the populations and communities in these ecosystems in the future. This paper represents a synthesis effort of the U.S. National Science Foundation-funded Long-Term Ecological Research (LTER) network addressing the core research area of {\textquotedblleft}populations and communities.{\textquotedblright} The objective of this effort was to show the importance of long-term data collection and experiments for addressing the hardest questions in scientific ecology that have significant implications for environmental policy and management. Each LTER site developed at least one compelling case study about what their site could look like in 50{\textendash}100 yr as human and environmental drivers influencing specific ecosystems change. As the case studies were prepared, five themes emerged, and the studies were grouped into papers in this LTER Futures Special Feature addressing state change, connectivity, resilience, time lags, and cascading effects. This paper addresses the {\textquotedblleft}connectivity{\textquotedblright} theme and has examples from the Phoenix (urban), Niwot Ridge (alpine tundra), McMurdo Dry Valleys (polar desert), Plum Island (coastal), Santa Barbara Coastal (coastal), and Jornada (arid grassland and shrubland) sites. Connectivity has multiple dimensions, ranging from multi-scalar interactions in space to complex interactions over time that govern the transport of materials and the distribution and movement of organisms. The case studies presented here range widely, showing how land-use legacies interact with climate to alter the structure and function of arid ecosystems and flows of resources and organisms in Antarctic polar desert, alpine, urban, and coastal marine ecosystems. Long-term ecological research demonstrates that connectivity can, in some circumstances, sustain valuable ecosystem functions, such as the persistence of foundation species and their associated biodiversity or, it can be an agent of state change, as when it increases wind and water erosion. Increased connectivity due to warming can also lead to species range expansions or contractions and the introduction of undesirable species. Continued long-term studies are essential for addressing the complexities of connectivity. The diversity of ecosystems within the LTER network is a strong platform for these studies.}, keywords = {alpine tundra; Antarctic polar desert; arid grassland; arid shrubland; coastal; estuary; salt marsh; Special Feature: Forecasting Earth{\textquoteright}s Ecosystems with Long-Term Ecological Research; urban ecosystem}, doi = {10.1002/ecs2.3432}, url = {files/bibliography/21-016.pdf}, author = {Iwaniec, David and Micheal Gooseff and Katharine N. Suding and David Samuel Johnson and Reed, Daniel C. and Debra C. Peters and M.B. Adams and Barretyt, John E. and Brandon T Bestelmeyer and Max Castoroni and Cook, Elizabeth M. and Davidson, Melissa J. and Peter M. Groffman and Niall Hanan and L. Huenneke and Johnson, Pieter J.C. and McKnight, Diane M. and Robert J. Miller and Gregory S. Okin and Preston, Daniel L. and Andrew Rassweiler and Ray, Chris and O. E. Sala and Robert L. Schooley and Timothy R Seastedt and Spasojevic, Marko J. and Enrique Vivoni} } @article {JRN55291, title = {Consequences of pi{\~n}on-juniper woodland fuel reduction: Prescribed fire increases soil erosion while mastication does not}, journal = {Ecosystems}, year = {2021}, month = {5/7/2021}, abstract = {Fire suppression has increased fuel load and the risk of catastrophic wildfire in forest and woodland ecosystems across the Western United States. In an effort to reduce fuel load and restore historical structure and function, land managers have implemented fuel reduction treatments on millions of acres. Reducing fuel loads protects people, structures, and in some cases, improves ecosystem health. However, the ecological risks of soil surface disturbance related to fuel reduction strategies, and subsequent soil erosion, may be significant in some cases. Here, we examined the effects of common fuel reduction strategies (mechanical mastication and two techniques for prescribed burning) on wind and water erosion in two upland pi{\~n}on-juniper woodlands in SE Utah over 2 years. We also tested the impact of broadcast seeding coupled with fuel reduction as a way to mitigate erosional soil loss. Finally, we analyzed biotic and abiotic predictor variables to evaluate important drivers of soil erosion following fuel treatments. We found that both techniques for prescribed burning{\textemdash}pile burning and broadcast burning{\textemdash}increased wind-related sediment fluxes by an average of 11-fold and 58-fold, respectively. Mastication did not increase wind-related losses over untreated controls. Erosional fluxes measured at silt fences, that captured both wind- and water-driven sediments, followed similar trends with moderate increases from pile burning (fivefold) but larger increases from broadcast burning (17-fold). Seeding did not affect erosion rates. Our results suggest that prescribed fire significantly increases soil erosion in fuel-treated pi{\~n}on-juniper woodlands and may be a degradation pathway when implementing treatments.}, keywords = {biological soil crusts (biocrusts), erosion, fuels management, mechanical mastication, pinon-juniper, prescribed fire, restoration}, doi = {10.1007/s10021-021-00644-6 }, url = {files/bibliography/21-027.pdf}, author = {Claire C. Karban and M. Miller and Jeffrey E. Herrick and N. Barger} } @article {JRN55342, title = {Can cattle geolocation data yield behavior-based criteria to inform precision grazing systems on rangeland?}, journal = {Livestock Science}, volume = {255}, year = {2021}, month = {12/5/2021}, pages = {104801}, abstract = {A key challenge of precision grazing systems is identifying behavior anomalies associated with situations of reduced animal production and wellbeing. We determined typical ranges of diel variation of movement and activity patterns of steers on rangeland to identify metrics that could serve as sensitive indicators of behavior anomalies. Seventeen Raramuri Criollo or Criollo crossbred yearling steers weighing 318 {\textpm} 9.3 kg (winter; W) or 358 {\textpm} 8.4 kg (late summer; LS) were fitted with GPS collars that recorded animal location at 5-min intervals. Steers grazed a 3,215-ha rangeland pasture for approximately 67 d in W or LS of 2016 and 2017. GPS data were used to derive 22 commonly monitored behavior variables. Means and day-to-day variation (CV\%) of all behavior metrics were calculated for each animal as well as linear correlations between the CV of each behavior and ADG. Daily time spent resting or grazing exhibited the least day-to-day variation in both W and LS (CV resting =10.8 and 9.9\%, respectively; CV grazing =13.8 and 14.8\%, respectively); predawn area explored (CV =240.8\%) and time spent at drinkers (CV =336.6\%) exhibited the most daily variation in W and LS, respectively. During W, increasing day-to-day variation in daytime distance traveled and area explored, as well as daily time spent traveling were associated with increasing ADG (r = 0.56 to 0.58; P < 0.05). In LS, steers with greater CV for 24-h area explored, time spent traveling, or daytime distance traveled tended to gain less weight (r =-0.77 to -0.84; P < 0.01), while steers with more flexible 24 hour path sinuosity tended to gain more weight (r = 0.93; P < 0.01). Behavior metrics more closely associated with forage intake processes, such as daily time spent grazing or resting, exhibited lowest diel variation levels and could be used to diagnose non-normal behavior of cattle on rangeland.}, keywords = {Average daily weight gain, beef cattle, GPS monitoring, Precision grazing, Precision livestock ranching}, doi = {10.1016/j.livsci.2021.104801}, url = {files/bibliography/21-053.pdf}, author = {Matthew M. McIntosh and Andr{\'e}s F. Cibils and Richard E. Estell and Qixu Gong and Huiping Cao and Amy L. Gonzalez and S. Nyamuryekung{\textquoteright}e and S. Spiegal} } @conference {JRN55340, title = {Conventional vs Heritage cattle supplement intake, weight-gains, and body condition scores on Chihuahuan desert pasture}, year = {2021}, month = {10/08/2021}, abstract = {Use of adapted beef cattle biotypes is gaining momentum as a novel management strategy for limiting the environmental footprint of ranching and adapting to climate change in the southwest. We compared supplement intake (SI), calf birthweights, cow weights, and body condition scores (BCS) of desert-adapted Brangus (BR; n = 15) vs. Raramuri Criollo (RC; n = 28) cows in four adjacent pastures (1098{\textpm}85 ha) for three months (Mar 7 {\textendash} Jun 9, 2020) using ANOVA for a RCBD (significance at P < 0.05). Cows had ad libitum access to 18\% crude protein lick tubs in all pastures, which were weighed weekly to determine SI. Brangus cows had greater SI than RC, both overall (BR: 0.21{\textpm}0.04 vs. RC: 0.08{\textpm}0.03 kg{\texttimes}cow{\texttimes}d-1) and on a metabolic bodyweight basis (BR: 2.31{\textpm}0.09 vs. RC: 0.95{\textpm}0.09 g{\texttimes}kg0.75). All cows were bred to Brangus bulls and calf birth weights were not different between biotypes (BR: 31.5 {\textpm} 1.0; RC: 29.6{\textpm}0.9 kg). Brangus cows weighed more at the beginning (535.0{\textpm}14.8 kg) and end (582.2{\textpm}14.5 kg) of the study compared to RC (beginning: 345.5{\textpm}11.8 kg; end: 357.0{\textpm}12.0 kg). Percent of bodyweight change was not different between biotypes (BR: 8.51{\textpm}2.35; RC: 2.85{\textpm}1.81 \%). On a 1 to 5 scale, BCS of Brangus (4.06{\textpm}0.09) was greater than RC (3.18 {\textpm} 0.07) at the onset of the study, but biotypes had similar BCS at the end of the trial (BR: 4.09 {\textpm} 0.09; RC: 3.89{\textpm}0.08). Our preliminary results indicate that lighter RC cows were capable of gaining bodyweight and improving BCS with reduced SI, both overall and on a metabolic bodyweight basis. This finding may reflect lower nutrient requirements, better relative efficiencies and lesser grazing impacts on desert rangelands by RC cattle. Future studies will seek to replicate these breed-comparison trials over multiple years, research sites, and supply chains, with an emphasis on overall systems production efficiency and sustainability.}, keywords = {body condition scores, Chihuahuan desert pasture, Conventional vs Heritage cattle, supplement intake, weight- gains}, doi = {10.1093/jas/skab235.687}, url = {files/bibliography/21-051.pdf}, author = {Matthew M. McIntosh and Richard E. Estell and Andr{\'e}s F. Cibils and Andrew Cox and S. Nyamuryekung{\textquoteright}e and Danielle Duni and G. Duff and S. Spiegal and Carolina Brandani and S. A. Utsumi and V. Gouvea} } @article {JRN55270, title = {Community Forests Prepare for Climate Change}, journal = {EOS}, volume = {102}, year = {2021}, month = {02/2021}, abstract = {Better soil moisture information with spatial and temporal resolutions relevant for assessing fuel bed conditions and wildfire probability offers promise for improving fire danger ratings. Wildfires consumed more than 3.5 million hectares in the United States in 2018 and federal fire suppression costs topped $3 billion USD. These fires took a severe toll on many communities, resulting in the destruction of more than 18,000 residences and the deaths of more than 100 people. Wildfire damages like these are a threat in many nations, and researchers from across the globe, and across multiple scientific disciplines, are working to improve fire danger rating systems to help protect natural resources and human health and safety. One new concept emerging as a valuable contribution to this effort is the integration of soil moisture information as a predictor of wildfire probability. Soil moisture, particularly within the root zone, is a key link between weather conditions, such as precipitation and temperature, and the characteristics of the live vegetative {\textquotedblleft}fuel bed{\textquotedblright}, such as fuel moisture and fuel loads. These dynamic vegetation characteristics strongly influence wildfire probability and can be challenging to model and monitor at relevant spatial and temporal scales using field data or optical remote sensing of fuel moisture (e.g., remote sensing live fuel moisture models contain relatively large margins of error that varies by vegetation type). Soil moisture monitoring capabilities, in contrast, have been steadily growing due to the development of in situ networks and dedicated satellites. While the relationships between soil moisture, fuel conditions, and wildfire occurrence have long been intuitively understood, the increasing availability of soil moisture information is creating significant opportunities to quantify these relationships and incorporate them into new or existing weather-based fuel moisture models and fire danger rating systems. }, doi = {https://doi.org/10.1029/2021EO154456}, url = {files/bibliography/21-006.pdf}, author = {Peterson, Courtney L. and Brandt, Leslie A. and Emile H. Elias and Hurteau, Sarah R.} } @article {JRN55268, title = {Cattle grazing distribution patterns related to topography across diverse rangeland ecosystems of North America}, journal = {Rangeland Ecology \& Management}, volume = {75}, year = {2021}, month = {03/2021}, pages = {91-103}, abstract = {Livestock distribution in extensive rangelands of North America can present management challenges to land managers. Understanding the role of topography on livestock distribution, within and across diverse rangeland ecosystems, could provide land managers valuable information for adaptive management of livestock to address both conservation and production goals from these ecosystems. Here, we examine the influence of topography on grazing distribution unevenness and intensity of use of beef cattle in seven rangeland ecosystems spanning arid, semiarid, and subtropical environments. We focused on grazing distribution during the late growing season (summer and autumn) periods when topographic variation in rangelands is more coupled to low and nonuniform availability of high-quality forage. Pasture size and water sources strongly influence grazing distribution across ecosystems. High unevenness of grazing occurred in pastures with extensive distances to water, low stock density, and more rugged topography. Conversely, more uniform grazing distribution occurred in smaller, well-watered pastures that support higher stock density (animals per unit area) and gentler terrain. Comparison of two topographic indices, topographic wetness index and topographic position class index, in terms of their ability to predict cattle grazing distribution, revealed that categorical topographic position classes were more effective. For most arid and semiarid rangelands, livestock grazing distributions showed affinities for lowlands and flat plains compared with open slopes and uplands. In contrast to drier rangelands, livestock grazing distributions exhibited preference for upland and sloped areas of subtropical pastures, as low-lying areas with water-inundation likely curtailed selection. Across these diverse rangeland ecosystems of North America, results provide benchmark information on livestock grazing distribution to formulate improvements in adaptive management and decision making and incorporate technological advancements in precision livestock management to integrate abiotic environmental information with spatial movements of livestock and temporal vegetation dynamics.}, keywords = {agroecosystem management, Cattle Grazing distribution, semiarid rangeland, Subtropical pastures, Topographic position}, doi = {10.1016/j.rama.2020.12.002}, url = {files/bibliography/21-004.pdf}, author = {Raynor, E.J. and Gersie, S.P and Stephenson, M.B. and Patrick E. Clark and S. Spiegal and Raoul K. Boughton and C. Donovan Bailey and Andr{\'e}s F. Cibils and Smith, B.W. and J. D. Derner and Richard E. Estell and R. M. Nielson and D.J. Augustine} } @article {JRN55336, title = {Constraints and opportunities for detecting land surface phenology in drylands}, journal = {Journal of Remote Sensing}, volume = {2}, year = {2021}, month = {10/27/2021}, pages = {1-15}, abstract = {Land surface phenology (LSP) enables global scale tracking of ecosystem processes, but its utility is limited in drylands due to low vegetation cover and resulting low annual amplitudes of vegetation indices (VIs). Due to the importance of drylands for biodiversity, food security, and the carbon cycle it is necessary to understand limitations in measuring dryland dynamics. Here, using simulated data and multi-temporal unmanned aerial vehicle (UAV) imagery of a desert shrubland, we explore the feasibility of detecting LSP with respect to fractional vegetation cover, plant functional types, VI uncertainty, and two different detection algorithms. Using simulated data we found that plants with distinct VI signals, such as deciduous shrubs, can require up to 60\% fractional cover to consistently detect LSP. Evergreen plants, with lower seasonal VI amplitude, require considerably higher cover and can have undetectable phenology even with 100\% vegetation cover. Our evaluation of two algorithms showed that neither performed the best in all cases. Even with adequate cover, biases in phenological metrics can still exceed 20 days, and can never be 100\% accurate due to VI uncertainty from shadows, sensor view angle, and atmospheric interference. We showed how high-resolution UAV imagery enables LSP studies in drylands, and highlighted important scale effects driven by within canopy VI variation. With high-resolution imagery the open canopies of drylands are beneficial as they allow for straightforward identification of individual plants, enabling the tracking of phenology at the individual level. Drylands thus have the potential to become an exemplary environment for future LSP research.}, keywords = {constraints, detecting, drylands, land surface phenology, opportunities}, doi = {10.34133/2021/9859103}, url = {files/bibliography/21-048.pdf}, author = {Shawn D. Taylor and Dawn M. Browning and Ruben Baca and Feng Gao} } @article {JRN55306, title = {Comparative analysis of water budgets across the U.S. long-term agroecosystem research network}, journal = {Journal of Hydrology}, volume = {588}, year = {2020}, month = {05/04/2020}, abstract = {Understanding the movement and storage of water within agricultural landscapes as functions of management and climate is essential for more efficient and sustainable water use. However, knowledge of water storage and fluxes on U.S. agricultural lands is largely incomplete. The Long-Term Agroecosystem Research (LTAR) network provides a unique and geographically diverse set of agricultural study sites in the United States. The objectives of this study were to: 1) characterize the hydrologic variability across the LTAR network; 2) identify data gaps in the water budgets across the LTAR network; and 3) identify opportunities to leverage the LTAR network to improve understanding of water budgets across agricultural landscapes. For each of the 18 LTAR sites, we developed water budgets on an average annual basis. Uncertainties for each component were based on the quantification method and the length of the data sets. Uncertainty propagation methods combined these uncertainties and the unquantified components to calculate an overall water budget uncertainty. Datasets length ranged from three to 50 years, depending on the component and the site. The network covers a range of precipitation from 240 to 1400 mm yr-1, evapotranspiration from 228 to 1080 mm yr-1, and surface runoff and subsurface flow from negligible to 1500 mm yr-1. However, uncertainties of where all the water is going remained high, in part because soil water storage and downward movement of water were often neglected or measured for very short periods, resulting in average water budget uncertainty of 25\% of the water inputs. More accurate measurement of the major inputs and outputs, and direct measurement of water content and percolation are keys to understanding how agricultural lands affect terrestrial water budgets.}, keywords = {evapotranspiration, hydrologic characterization, irrigation, percolation, precipitaiton, soil water storage, subsurface outflows, surface outflows, water budget}, doi = {10.1016/j.jhydrol.2020.125021}, url = {files/bibliography/20-040.pdf}, author = {Claire Baffaut and J. M. Baker and Joel A. Biederman and David D. Bosch and Erin S. Brooks and Anthony R. Buda and Eleonora M. Demariac and Emile H. Elias and Gerald N. Flerchinger and David C. Goodrich and Stephen K. Hamilton and Stuart P. Hardegree and R. Daren Harmel and David L. Hoover and K.W. King and Peter J. A. Kleinman} } @conference {JRN55299, title = {Challenges and opportunities for manureshed management across U.S. dairy systems}, booktitle = {ASA-CSSA-SSSA Annual Meeting Abstracts}, year = {2020}, month = {11/09/2020}, abstract = {Dairy production is dispersed throughout the United States, but there are a few areas of high concentration in the Northeast, the Upper Midwest, the Southern Plains, Idaho, and California. The predominant management practices differ substantially from region to region, in size, degree of confinement, primary manure form (solid or liquid), and method of storage. As a result, the opportunities and challenges to expanding dairy manuresheds also vary widely. We present case studies of the various systems, to examine how well manure sources are matched to cropland sinks in each case, and to highlight possible areas of concern.}, author = {J. M. Baker and Curtis Dell and S. Spiegal and Porter, Sarah and Leytem, April B. and Colton K Flynn and Ray Bryant and Bjorneberg, David L. and C. A. Rotz and Hagevoot, Robert and Jebediah C. Williamson and A. L. Slaughter and S. Bittman and Peter J. A. Kleinman} } @conference {JRN55244, title = {Climate and phenology network synergies for sustainable agriculture}, booktitle = {Ecological Society of America}, year = {2020}, month = {08/2020}, address = {Virtual Conference}, abstract = {Agricultural producers face multiple challenges in a consistently changing climate and managed agroecosystems pose a challenge for broad-scale forecasts for yield given myriad cropping and management scenarios. There is a pressing need for integrative frameworks to support and inform management strategies that adapt to climate change for a diverse set of stakeholders. We use phenology {\textendash} the study of seasonal patterns in plant productivity {\textendash} to examine historical and current responses to regional climate in the continental U.S. We identify opportunities and knowledge gaps through case studies that involve data products from multiple research and observational networks. Poster $\#$ 82205.}, author = {Dawn M. Browning and Shawn D. Taylor} } @article {JRN55157, title = {Comparison of soil-aggregate crushing-energy meters}, journal = {Aeolian Research}, volume = {42}, year = {2020}, month = {01/10/2020}, abstract = {

Dry aggregate stability (DAS) is an important factor influencing soil wind erosion, dust emission and crop production. Historically and to the present, DAS has been determined using a horizontal- or vertical-plate crushing meter (Soil-Aggregate Crushing-Energy Meter, hereafter SACEM). The intent of this paper was to compare the performance of horizontal-plate SACEM with a commercial penetrometer (Mohr Digi-Test, hereafter MDT). The performance of both instruments was tested on aggregates collected from various soil types, crop rotations, soil amendments, and tillage systems across the inland Pacific Northwest United States (iPNW). Results indicated no consistently significant difference in DAS measured by the MDT and SACEM. However, there was evidence that SACEM under-estimated or MDT over-estimated DAS by 74 to 368\% in measuring the stability of strong aggregates (DAS \> 3 J kg-1). Both instruments measured higher DAS for no-tillage summer fallow, winter wheat-summer fallow (WW-SF) rotations, and no green manure treatments compared with other tillage practices, oilseed rotations, and green manure treatments. The SACEM that has historically been used in measuring soil DAS can be replaced by the commercial penetrometer (MDT). Nonetheless, differences in the performance of instruments in measuring the stability of strong aggregates poses risks.

}, keywords = {Abrasion, Binding energy, Dry aggregate stability, dust emission, Particle cohesion, wind erosion}, doi = {10.1016/j.aeolia.2019.100559}, url = {files/bibliography/20-002.pdf}, author = {H. Pi and David Huggins and Nicholas Webb and Brenton Sharrat} } @article {JRN55217, title = {Critical standing crop residue amounts for wind erosion control in the inland Pacific Northwest, USA}, journal = {CATENA}, volume = {195}, year = {2020}, month = {06/2020}, chapter = {104742}, abstract = {Crop residue is an important factor influencing wind erosion of cultivated soils. Establishing soil surface protection afforded by standing crop residue is critical for land managers seeking to reduce or prevent soil loss by wind erosion and the impacts of blowing dust from agricultural lands. The objectives of this study were to evaluate the effect of standing residue on soil wind erosion in the inland Pacific Northwest (iPNW), USA, and test the performance of the plant factor algorithm~of the Agricultural Policy/Environmental eXtender (APEX) and Revised Wind Erosion Equation (RWEQ) models in~influencing~soil loss. The effect of standing winter wheat, spring canola, and garbanzo residue on wind erosion, remaining from major commodity crops in the region, was tested in a wind tunnel using four levels of residue density. The impact of standing residue in controlling wind erosion was compared and analyzed in terms of residue density and their respective frontal area index. Our results show that residue at a density characteristic of the production environment (110 plants m-1 for winter wheat, 20 plants m-1 for canola, and 16 plants m-1 for garbanzo~bean) provided significant protection to the soil surface from wind erosion. Soil loss at this level of residue density was reduced by 73.3, 53.4, and 60.9\% for respectively winter wheat, spring canola, and garbanzo (frontal area indexes are 0.172, 0.104, and 0.026 respectively) compared with a surface without residue. The soil surface was found to be at significant risk from wind erosion when residue densities of the three crop types were <50\% of the typical production amounts. Although not consistently significant, soil loss decreased as wind direction shifted from parallel to perpendicular with the standing residue row. The APEX model adequately simulated winter wheat and spring canola residue protection but had low accuracy in representing garbanzo residue effects relative to the wind tunnel experiments. In contrast, the RWEQ model appeared inadequate in simulating soil loss for the winter wheat and canola treatments but adequately represented garbanzo residue effects. Differences in model accuracy for different crop types must be considered by producers and managers to determine whether model information used to select practices to control wind erosion are likely to result in under- or over-protection of soil resources.}, keywords = {Chickpea, Frontal area index, Spring canola, Wind erosion model, Winter wheat}, doi = {https://doi.org/10.1016/j.catena.2020.104742}, url = {files/bibliography/20-025.pdf}, author = {H. Pi and Nicholas Webb and David Huggins and Brenton Sharrat} } @article {JRN55170, title = {Collaborative Approaches to Strengthen the Role of Science in Rangeland Conservation}, journal = {Rangelands}, volume = {41}, year = {2019}, month = {October 2019}, pages = {218-226}, abstract = {The use of science to inform conservation practices is limited by broad generalities generated from limited sampling alongside narrow ecosystem service perspectives. Collaborative science approaches featuring {\textquotedblleft}social-ecological system{\textquotedblright} perspectives are being used as a means to improve the utility of science. We review our approach to collaborative science to improve brush management outcomes in rangelands in the Chihuahuan Desert. Expanding the use and utility of collaborative science requires stable support via targeted funding and technical expertise, as well as web-based tools and mobile applications that link specific locations to science information and conservation practice guidelines.}, keywords = {brush management, Collaborative adaptive management, ecological sites, monitoring, State transition models}, doi = {10.1016/j.rala.2019.08.001}, url = {files/bibliography/19-028.pdf}, author = {Brandon T Bestelmeyer and Laura M. Burkett and Leticia Lister and Joel R. Brown and Robert L. Schooley} } @article {JRN55142, title = {Changes in below ground biodiversity during ecosystem development}, journal = {Proceedings of the National Academy of Sciences}, volume = {116}, year = {2019}, pages = {6891{\textendash}6896}, abstract = {

We do not know how and why belowground biodiversity may change as soils develop over centuries to millennia, hampering our ability to predict the myriad of ecosystem processes regulated by belowground organisms under changing environments. We conducted a global survey of 16 soil chronosequences spanning a wide range of ecosystem types and found that in less productive ecosystems, increases in belowground biodiversity followed increases in plant cover, but in more productive ecosystems, acidification during soil development was often associated with declines in belowground biodiversity. The biodiversity of multiple soil organisms exhibited similar patterns over time, but in contrast to expectations, changes in plant diversity were not associated with corresponding changes in belowground biodiversity.Belowground organisms play critical roles in maintaining multiple ecosystem processes, including plant productivity, decomposition, and nutrient cycling. Despite their importance, however, we have a limited understanding of how and why belowground biodiversity (bacteria, fungi, protists, and invertebrates) may change as soils develop over centuries to millennia (pedogenesis). Moreover, it is unclear whether belowground biodiversity changes during pedogenesis are similar to the patterns observed for aboveground plant diversity. Here we evaluated the roles of resource availability, nutrient stoichiometry, and soil abiotic factors in driving belowground biodiversity across 16 soil chronosequences (from centuries to millennia) spanning a wide range of globally distributed ecosystem types. Changes in belowground biodiversity during pedogenesis followed two main patterns. In lower-productivity ecosystems (i.e., drier and colder), increases in belowground biodiversity tracked increases in plant cover. In more productive ecosystems (i.e., wetter and warmer), increased acidification during pedogenesis was associated with declines in belowground biodiversity. Changes in the diversity of bacteria, fungi, protists, and invertebrates with pedogenesis were strongly and positively correlated worldwide, highlighting that belowground biodiversity shares similar ecological drivers as soils and ecosystems develop. In general, temporal changes in aboveground plant diversity and belowground biodiversity were not correlated, challenging the common perception that belowground biodiversity should follow similar patterns to those of plant diversity during ecosystem development. Taken together, our findings provide evidence that ecological patterns in belowground biodiversity are predictable across major globally distributed ecosystem types and suggest that shifts in plant cover and soil acidification during ecosystem development are associated with changes in belowground biodiversity over centuries to millennia.

}, issn = {0027-8424}, doi = {10.1073/pnas.1818400116}, url = {files/bibliography/DelgadoBaquerizoetal2019.pdf}, author = {Delgado-Baquerizo, Manuel and Richard Bardgett and Vitousek, Peter M. and F. Maestre and Mark A. Williams and D.J. Eldridge and Lambers, Hans and Neuhauser, Sigrid and Gallardo, Antonio and Garc{\'\i}a-Vel{\'a}zquez, Laura and O. E. Sala and Abades, Sebasti{\'a}n R. and Alfaro, Fernando D. and Arrefaine Berhe and Bowker, Matthew A. and Courtney M. Currier and Cutler, Nick A. and Hart, Stephen C. and Hayes, Patrick E. and Hseu, Zeng-Yei and Kirchmair, Martin and Pe{\~n}a-Ram{\'\i}rez, Victor M. and P{\'e}rez, Cecilia A. and Sasha C. Reed and Santos, Fernanda and Siebe, Christina and Sullivan, Benjamin W. and Weber-Grullon, Luis and Fierer, Noah} } @article {JRN55137, title = {Climate change impacts on wind and water erosion on US rangelands}, journal = {Journal of Soil and Water Conservation}, volume = {74}, year = {2019}, month = {07/2019}, pages = {405-418}, chapter = {405}, abstract = {

Soil erosion by water and wind in US rangelands has serious implications for rangeland health, food security, and poses significant hazards to human health and communities. Accordingly, understanding how future climate change may impact soil erosion is critical for developing appropriate management strategies that mitigate negative impacts to the extent practical and potentially build resilience. Here, we review potential impacts of climate change on controls of erosion in US rangelands and discuss potential erosion responses. Projected climate changes are expected to have regionally variable effects on important controls of erosion, especially vegetation cover; community composition; frequency, magnitude, and geographical range of fire disturbance; and high intensity, erosive weather events, all of which have the potential to increase rangeland vulnerability to erosion. We identify knowledge gaps relevant to these controls and discuss management considerations to address climate change impacts to soil erosion concerns for US rangelands. We recommend using existing monitoring data to create assessments of vulnerability, that soil erosion should be explicitly included in management benchmarks and decision support tools, and that no-regrets management options be implemented in anticipation of future impacts, which can improve resilience and the efficacy of climate change adaptation.

}, keywords = {climate change, rangeland, soil erosion, water erosion, wind erosion}, doi = {doi.org/10.2489/jswc.74.4.405}, url = {files/bibliography/19-017.pdf}, author = {Brandon Edwards and Nicholas Webb and David A. Brown and Emile H. Elias and Dannele E. Peck and Frederick B. Pierson and Jason C. Williams and Jeffrey E. Herrick} } @article {JRN55172, title = {Crop Vulnerability to Weather and Climate Risk: Analysis of Interacting Systems and Adaptation Efficacy for Sustainable Crop Production}, journal = {Sustainability}, volume = {11}, year = {2019}, month = {23 November 2019}, pages = {6619}, abstract = {

Climate change is increasing mean and extreme temperatures in the Southwestern United States, leading to a suite of changes affecting agricultural production. These include changes in water, soils, pathogens, weeds, and pests comprising the production environment. The aim of this synthesis is to describe the anticipated leading agricultural pressures and adaptive responses, many of which are near-term actions with longer-term consequences. In the semiarid Southwestern United States, climate change is expected to increase water scarcity. Surface water shortage is the leading reason for recent diminished crop yields in the Southwest. Drought and lack of water represent the leading regional weather-related cause of crop loss from 1989 to 2017. Thus, water scarcity has been and will continue to be a critical factor leading to regional crop vulnerability. Soils, pathogens, weeds, and insects are components of the agricultural production environment and are directly influenced by near-term weather and long-term climate conditions. Field crops, vegetable crops, and perennial crops have unique production requirements and diverse management options, many already used in farm management, to cope with production environment changes to build climate resilience. Farmers and ranchers continuously respond to changing conditions on a near-term basis. Long-term planning and novel adaptation measures implemented may now build nimble and responsive systems and communities able to cope with future conditions. While decision-support tools and resources are providing increasingly sophisticated approaches to cope with production in the 21st century, we strive to keep pace with the cascading barrage of inter-connected agricultural challenges.

}, doi = {10.3390/su11236619}, url = {files/bibliography/19-026.pdf}, author = {Emile H. Elias and Robert Flynn and Omololu John Idowu and J.T. Reyes and Soumaila Sanogo and Brian J. Schutte and Ryann Smith and Caitriana Steele and Carol Sutherland} } @article {JRN55133, title = {Constraints on shrub cover and shrub-shrub competition in a U.S. southwest desert}, journal = {Ecosphere}, volume = {10}, year = {2019}, month = {02/2019}, pages = {1-16}, chapter = {1}, abstract = {

The cover of woody perennial plants (trees and shrubs) in arid ecosystems is at least partially constrained by water availability. However, the extent to which maximum canopy cover is limited by rainfall, and the degree to which soil water holding capacity and topography impacts maximum shrub cover are not well understood. Similar to many other deserts in the U.S. southwest, plant communities at the Jornada Basin Long-Term Ecological Research (LTER) site in the northern Chihuahuan Desert have experienced a long-term state-change from perennial grassland to shrubland dominated by woody plants. To better understand this transformation, and the environmental controls and constraints on shrub cover, we created a shrub cover map using high spatial resolution images and explored how maximum shrub cover varies with landform, water availability, and soil characteristics. Our results indicate that when clay content is below ~18\%, the upper limit of shrub cover is positively correlated with plant available water as mediated by surface soil clay influence on water retention. At surface soil clay contents \>18\%, maximum shrub cover decreases, presumably because the amount of water percolating to depths preferentially used by deep-rooted shrubs is diminished. In addition, the relationship between shrub cover and density suggests that self-thinning occurs in denser stands in most landforms of the Jornada Basin, indicating that shrub-shrub competition interacts with soil properties to constrain maximum shrub cover in the northern Chihuahuan Desert.

}, keywords = {Jornada Basin Long-Term Ecological Research (LTER), shrub-shrub competition, Southwest U.S. drylands, Special Feature: Dynamic Deserts, woody plant encroachment}, doi = {doi.org/10.1002/ecs2.2590}, url = {files/bibliography/19-014.pdf}, author = {W Ji and Niall Hanan and Dawn M. Browning and Curtis H. Monger and Debra C. Peters and Brandon T Bestelmeyer and Steven R. Archer and Ross, C. Wade and Lind, Brianna M. and Julius Anchang and Kumar, Sanath S. and Prihodko, Lara} } @conference {JRN55143, title = {Carcass characteristics of Criollo and Criollo crossbred steers raised on Chihuahuan Desert rangeland}, booktitle = {2019 ASAS-CSAS Annual Meeting and Trade Show}, year = {2019}, month = {07/10/2019}, publisher = {American Society of Animal Science (ASAS-CSAS)}, organization = {American Society of Animal Science (ASAS-CSAS)}, address = {Austin, TX}, abstract = {

We compared carcass characteristics of 11 Raramuri Criollo (RC) and 8 Criollo x Brangus crossbred (XC) steers raised together on Chihuahuan Desert rangeland. Steers entered the trial (completely randomized design) at approximately 5 months of age (December, 2015). Initial weights of RC and XC steers were 233.7 {\textpm} 7.8 and 231.4 {\textpm} 9.2 kg, respectively. Steers weighed 423.1 {\textpm} 7.8 (RC) and 483.0 {\textpm} 9.2 (XC) kg at 29 months of age (February 1, 2018), before being shipped to South Dakota where they were fed hay for approximately one month until slaughter (February 28, 2018). Carcass characteristics, such as hot (HCW) and cold carcass weights (CCW), preliminary yield grade (PYG), ribeye area (REA), marbling score (MS), and quality grade (QG) were assessed. Breed effects for all variables (excluding QG) were analyzed using SAS Proc Mixed; SAS Proc Npar1way was used to evaluate QG. Compared to XC, RC steers had lighter (P \< 0.01) HCW (220 {\textpm} 5 vs. 265 {\textpm} 6 kg) and CCW (210 {\textpm} 5 vs. 254 {\textpm} 6 kg), and smaller (P \< 0.01) REA (56 {\textpm} 1.4 vs. 61.7 {\textpm} 1.6 cm2). No differences (P \> 0.05) were observed between RC and XC steers in PYG (2.3 {\textpm} 0 vs. 2.4 {\textpm} 0.2) or MS (452 {\textpm} 31 vs. 456 {\textpm} 36). Average QG for all carcasses was between high standard and low choice and was not different (P \> 0.05) for RC versus XC carcasses. Our preliminary results show no major difference in carcass quality parameters of RC and XC steers developed on Chihuahuan Desert rangeland.

}, author = {Matthew M. McIntosh and Andr{\'e}s F. Cibils and Richard E. Estell and Amy L. Gonzalez and S. Spiegal and Blair, A. and S. Nyamuryekung{\textquoteright}e and S. Soto-Navarro and C. Tolle} } @article {JRN55274, title = {Competition suppresses shrubs during early, but not late, stages of arid grassland{\textendash}shrubland state transition}, journal = {Functional Ecology}, volume = {33}, year = {2019}, month = {3/7/2019}, pages = {1480{\textendash}1490}, abstract = {1. Transitions from grass to woody plant dominance, widely reported in arid systems, are typically attributed to changes in disturbance regimes in combination with abiotic feedbacks, whereas biotic mechanisms such as competition and facilitation are often overlooked. Yet, research in semi-arid and subhumid savannas indicates that biotic interactions are important drivers in systems at risk for state transition. We sought to bridge this divide by experimentally manipulating grass-on-shrub and shrub-on-shrub interactions in early and late stages of grassland{\textendash}shrubland state transition, respectively, and to assess the extent to which these interactions might influence arid land state transition dynamics. 2. Target Prosopis glandulosa shrubs had surrounding grasses or conspecific neighbours left intact or killed with foliar herbicide, and metrics of plant performance were monitored over multiple years for shrubs with and without grass or shrub neighbours. 3. Productivity of small shrubs was enhanced by grass removal in years with above average precipitation, a result not evident in larger shrubs or during dry years. Proxy evidence based on nearest neighbour metrics suggested shrub{\textendash}shrub competition was at play, but our experimental manipulations revealed no such influence. 4. Competition from grasses appears to attenuate the rate at which shrubs achieve the size necessary to modify the physical environment in self-reinforcing ways, but only during the early stages of shrub encroachment. Our results further suggest that at late stages of grassland-to-shrubland state transitions, shrub{\textendash}shrub competition will not slow the rate of shrub expansion, and suggest that maximum shrub cover is regulated by something other than density-dependent mechanisms. We conclude that grass effects on shrubs should be included in assessments of desert grassland state transition probabilities and rates, and that desertification models in arid ecosystems that traditionally focus on disturbance and abiotic feedbacks should be broadened to incorporate spatial and temporal variations in competitive effects.}, keywords = {Chihuahuan Desert, competition, grassland, shrubland, state transition, woody plant encroachment}, doi = {10.1111/1365-2435.13336}, url = {files/bibliography/19-029.pdf}, author = {Nathan Pierce and Steven R. Archer and Brandon T Bestelmeyer} } @article {JRN55182, title = {Cattle, conservation, and carbon in the western Great Plains}, journal = {Journal of Soil and Water Conservation}, volume = {75}, year = {2019}, month = {December 2019}, abstract = {

Rangelands have garnered attention for their potential to store carbon (C) and have been included in France\’s 4 per 1,000 initiative (Minasny et al. 2017), methods for maintaining or increasing C in grassland soils (American Carbon Registry 2013; Verified Carbon Standard 2017), and portfolios of natural climate solutions (Griscom et al. 2017; Fargione et al. 2018). Rangelands are used to graze livestock, and they provide habitat for species, C storage, and other environmental benefits. Rangelands cover nearly half the world\’s terrestrial surface and store up to 20\% of the global soil organic C (Conant 2012). However, rangelands are being converted to other land uses such as cropland (Lark et al. 2015), housing, industry, transportation, and energy production. Approximately 600,000 ha (1.48 \× 106 ac) of US rangelands were converted to other uses between 2007 and 2012, and another 360,000 ha (0.89 \× 106 ac) between 2012 and 2015 (USDA 2018). Despite the increasing attention being given to soil C, some reports urging soil C management do not mention avoiding conversion (Lal 2019). We suggest that avoiding the loss of rangelands should be given more attention than it currently receives because it offers a well-established approach to retaining soil C along with the other ecosystems services that rangelands provide.

}, keywords = {carbon, cattle, conservation, western Great Plains}, doi = {10.2489/jswc.75.1.5A}, url = {files/bibliography/20-006.pdf}, author = {John S. Sanderson and Curtis Beutler and Joel R. Brown and Ingrid C. Burke and Teresa Chapman and R. Conant and J. D. Derner and Mark Easter and S. Fuhlendorf and Grady Grissom and Jeffrey E. Herrick and Daniel Liptzin and Jack A. Morgan and Rachel Murph and Chris Pague and Imtiaz Rang} } @article {JRN55135, title = {Comparison of 2 vegetation height methods for assessing greater sage-grouse seasonal habitat}, journal = {Wildlife Society Bulletin}, volume = {42}, year = {2018}, month = {05/2018}, pages = {213-224}, chapter = {213}, abstract = {

The 2015 Sage-Grouse Habitat Assessment Framework (HAF) was developed to evaluate habitat quality for sage-grouse (Centrocercus spp.), with the greater sage-grouse (C. urophasianus) as the primary focus of HAF evaluations and basis of the indicators in the HAF. Site-scale assessments of sage-grouse habitat can be completed using either data collection methods described in the HAF or core methods adopted by the U.S. Bureau of Land Management{\textquoteright}s Assessment, Inventory, and Monitoring (AIM) program. However, there is a discrepancy in how vegetation height is measured between HAF and AIM
methods, which has led to confusion as to which protocol should be used and if the AIM height method is compatible with the HAF for habitat assessments. Our objective was to use simulations and data from multiple study areas to determine how often differences between the 2 methods would result in a different determination of quality for the vegetation-height habitat indicator. We confirmed that the AIM method generally yields lower estimates of height than the HAF method because it estimates mean vegetation height whereas the HAF method estimates mean maximum height (d {\textonequarter} 0.031). However, differences between methods at the plot level most often were not substantial enough to lead to a different conclusion about the HAF vegetation-height indicator for habitat quality. There is value in implementing the AIM method because it is widely used for other monitoring purposes, and slight modifications to the AIM technique (i.e., increasing measurement frequency, adding measurements for both grasses and forbs) could improve usefulness for sage-grouse habitat assessments.

}, keywords = {Centrocercus urophasianus, greater sage-grouse, habitat assessment, indicator, monitoring, Vegetation height}, doi = {doi.org/10.1002/wsb.877}, url = {files/bibliography/18-026.pdf}, author = {Sean F. Di Stefano and Jason W. Karl and Sarah McCord and Nelson Stauffer and Makela, Paul and Mary Manning} } @article {JRN54906, title = {Contributions of hydrology to Vesicular Stomatitis Virus emergence in the Western USA}, journal = {Ecosystems}, volume = {22}, year = {2018}, month = {07/2018}, pages = {416-433}, chapter = {416}, abstract = {

Relationships between environmental variables associated with the spread of vector-borne pathogens, such as RNA viruses transmitted to humans and animals, remain poorly understood. \ Vesicular stomatitis (VS) is caused by a vector-borne, zoonotic RNA virus (VSV), and is the most common vesicular disease affecting livestock (domestic horses, cattle, pigs) throughout the Americas. This investigation focused on explaining patterns of \>1500 incidents of VS in livestock in the western US from 2004-2016 related to the ecology of the host-vector-virus-environment system. We investigated the relationship between VS incidents and habitat characteristics expected to be important to insect vectors: stream location, streamflow conditions, climate, and vegetation. Results show that VS incidents were distributed near the stream network with 72\% located within 1 km of lotic habitat. The watershed with highest number of VS confirmed premises had the largest mean premises distance from flowing water. Monthly incidents were closest to lotic habitat in April (x=525m) and furthest from lotic habitat in November, December and January (1,843m, 2,141n and 4,807m) indicating that initial infection near streams may spread away from these locations. All first incidents (n=35) occurred following peak annual streamflow, with 89\% (31 of 35) of these occurring after streams returned to baseflow. This finding indicated that surveillance for VS could be targeted spatially in locally-relevant geographical areas (i.e., near streams) and temporally relative to local streamflow conditions which can be remotely monitored via existing web-accessible information networks. Habitat modeling of 11 subwatersheds revealed somewhat different models for each watershed with several factors important in multiple watersheds such as higher horse density. In nine of the 11 watersheds, the highest model PC (31 to 71\%) represented either higher than average long-term mean temperature or lower than average long-term mean precipitation. Approaching habitat modeling on a watershed basis reveals information to support additional research. These spatial and temporal relationships showcase the importance of hydrological contributions to the emergence and distribution of an arthropod-borne disease in the western U.S.

}, doi = {10.1007/s10021-018-0278-5}, url = {/files/bibliography/19-004.pdf}, author = {Emile H. Elias and David McVey and Debra C. Peters and J. D. Derner and Angela Pelzel-McCluskey and Scott T. Schrader and Luis L Rodriguez} } @article {JRN54931, title = {County-level climate change information to support decision-making on working lands within USDA Climate Hub regions}, journal = {Climatic Change}, volume = {148}, year = {2018}, month = {06/2018}, pages = {355{\textendash}369}, chapter = {3}, abstract = {

Farmers, ranchers, and forest landowners across the USA make weather- and climate-related management decisions at varying temporal and spatial scales, often with input from local experts like crop consultants and cooperative extension (CE) personnel. In order to provide additional guidance to such longer-term planning efforts, we developed a tool that shows statistically downscaled climate projections of temperature and precipitation consolidated to the county level for the contiguous US. Using the county as a fundamental mapping unit encourages the use of this information within existing institutional structures like CE and other U.S. Department of Agriculture (USDA) programs. A {\textquotedblleft}quick-look{\textquotedblright} metric based on the spatial variability of climate within each county aids in the interpretation of county-level information. For instance, relatively higher spatial variability within a county indicates that more localized information should be used to support stakeholder planning. Changes in annual precipitation show a latitudinal dipole where increases are projected for much of the northern US while declines are projected for counties across the southern US. Seasonal shifts in county-level precipitation are projected nationwide with declines most evident in summer months in most regions. Changes in the spatial variability of annual precipitation for most counties were less than 10\ mm, indicating fairly spatially homogenous midcentury precipitation changes at the county level. Annual and seasonal midcentury temperatures are projected to increase across the USA, with relatively low change in the spatial variability (\<0.3\ {\textdegree}C) of temperature across most counties. The utility of these data is shown for forage and almond applications, both indicating a potential decline in production in some future years, to illustrate use of county-level seasonal projections in adaptation planning and decision-making.

}, keywords = {agriculture, climate change, Cooperative extension, decision-making, forestry, ranching, USDA climate hubs}, doi = {doi.org/10.1007/s10584-017-2040-y}, url = {files/bibliography/18-024.pdf}, author = {Emile H. Elias and Scott T. Schrader and John T Abatzoglou and D. K. James and Michael Crimmins and Weiss, Jeremy and A. Rango} } @article {JRN54922, title = {Controlling one-seed juniper saplings with small ruminants: What we{\textquoteright}ve learned}, journal = {Rangelands}, volume = {40}, year = {2018}, month = {10/2018}, pages = {129-135}, chapter = {129}, abstract = {

Protein supplements and polyethylene glycol increased juniper intake by small ruminants in all seasons except fall, when PSM concentrations were greatest. Terpenes were affected by season and sapling size, and were related to juniper intake by small ruminants. Small sapling browsing occurred most frequently in summer. Debarking of branches on taller saplings was greatest in spring. Ten years later, juniper kill ranged from 5-14\%. Growth suppression was still evident after 10 years; browsed saplings averaged 13 cm shorter than controls. Strategies to target grazing of one-seed juniper are more likely to succeed if aligned with periods when PSM are lowest.

}, keywords = {goats, phenology, plant secondary metabolites, protein supplementation, sheep, targeted grazing}, doi = {doi.org/10.1016/j.rala.2018.07.002}, url = {/files/bibliography/18-018.pdf}, author = {Richard E. Estell and Andr{\'e}s F. Cibils and S. A. Utsumi and Stricklan, D. and Butler, E. M. and Fish, A. I. and Amy Ganguli} } @proceedings {JRN54861, title = {Coordinating a national rangeland monitoring training program: Success and lessons learned}, volume = {January 28-February 2, 2018}, year = {2018}, month = {01/28/2018}, publisher = {Society for Range Management Meeting Proceedings}, address = {Reno, NV}, abstract = {

One of the best ways to ensure quality of information gathered in a rangeland monitoring program is through a strong and uniform set of trainings. Curriculum development and delivery of monitoring trainings poses unique challenges that are not seen in academic settings. Participants come from a range of educational and experience backgrounds. Additionally, participants may only have the period of the training to receive the necessary instruction before fully implementing the protocol as part of their job duties. Consequently, careful consideration for content delivery and hands on learning activities is critical for active learning. We present the lessons learned from the Bureau of Land Management{\textquoteright}s Assessment Inventory and Monitoring (AIM) training program with the partnership of USDA-ARS Jornada Experimental Range. The successes and lessons were developed from web-based and in-person trainings targeting BLM staff, seasonal staff, non-profit organizations, and academic partners for topics relating to data collection, analysis, database use and more. Consideration was given to the identification and education of both the target audience and the potential non-target audiences while taking into account the unique needs of adult learners. The AIM program has formatted training curriculum that addresses the needs of spatial, auditory, linguistic and kinesthetic learners. Challenges that impact training quality such as inconsistency in staff availability, a seasonal workforce, timing of data needs, phenology, and funding were also factored into the development of the training program. The importance of forming a training cadre and what factors should be assessed in this process has been an additional consideration. The final portion of the process was to review the most effective methods for assessing success. The training program of AIM is continually evolving, building on the success and lessons learned of the past to provide high quality information for rangeland management.

}, author = {Baili Foster and Sarah McCord and Emily Kachergis} } @proceedings {JRN54865, title = {Challenges and opportunities with standardized monitoring for management decison-making}, volume = {January 28-February 2, 2018}, year = {2018}, month = {01/28/2018}, publisher = {Society for Range Management Meeting Proceedings}, address = {Sparks, Nevada}, abstract = {

The importance of monitoring for adaptive management of rangelands has been well established. However, the actual use of monitoring data in rangeland management decisions has been modest despite extensive efforts to develop and implement monitoring programs from local to national scales. More effective use of monitoring data is critical to inform adaptive management, to empirically justify management decisions, and to ensure a return on resources invested in monitoring programs like the Bureau of Land Management{\textquoteright}s (BLM) Assessment, Inventory, and Monitoring (AIM) program. Several challenges limit the use of monitoring data in management decision making. First, there is often a disconnect between aspects of monitoring (e.g., indicators, sample design, timing) and information needs of managers for making decisions. This can arise from a lack of specific monitoring objectives tied to management decisions or from monitoring indicators being analyzed and presented in forms that do not mesh with land management workflows. Second, in many cases little information exists on how to interpret monitoring results with respect to land potential (e.g., is the amount of bare ground more than what is expected for this type of rangeland?). Third, given limited resources, monitoring data often produce estimates with large confidence intervals, which causes challenges for interpreting whether a change has occurred or a land health standard has been met. Fourth, there is a tension between flexibility to design monitoring around management needs for specific, immediate objectives and maintaining standard monitoring approaches to build long-term datasets. This has the effect of reinforcing short-term monitoring at the expense of investing in standardized efforts that could address multiple objectives over the long term. We describe these challenges in the context of the BLM AIM projects discussed during the symposium. We explore potential opportunities for addressing these challenges and how the AIM program can be leveraged for success.

}, author = {Jason W. Karl and Sarah McCord and Scott W. Miller} } @conference {JRN54909, title = {Can connectivity-mediated feedbacks to vegetation explain surprising ecological responses to catastrophic events?}, booktitle = {Ecological Society of America}, year = {2018}, month = {08/2018}, publisher = {Ecological Society of America}, organization = {Ecological Society of America}, address = {New Orleans, LA}, abstract = {

Multi-year extreme drought events that affect regional to sub-continental extents have catastrophic impacts on ecological systems. Drought impacts are often studied based on local factors, such as climate and soils, interacting with local ecological processes (e.g., competition between plants). However, spatial processes operating within broad extents can lead to connectivity-mediated feedbacks to the vegetation that overwhelm direct effects of drought and lead to unexpected landscape-scale heterogeneity. One of the most devastating droughts occurred in the Great Plains of North America in the 1930s. This climatic event combined with land management practices (plowing and subsequent abandonment) to result in broad-scale plant mortality, soil erosion, and dust storms. However, not all areas were affected similarly, even across short distances. We hypothesized that spatial discontinuities in impacts were related to: (1) local factors of climate, soil properties, and management and/or (2) connectivity by wind and/or water erosion from nearby locations. We integrated legacy data from the U.S. Department of Agriculture on production, management, and erosion with climatic and edaphic data (1920s to 1940s) for a 100-km gradient from western Iowa to eastern Nebraska. Responses were compared during the drought to responses for the same location in the 1920s (pre-drought) and the 1940s (post-drought). Our results show complex interactions among precipitation, temperature, soil properties, and management practices across this relatively short (100-km) gradient. Climatic drivers tended to be more important to production in the more mesic part of the gradient (IA), and soil properties became more important as precipitation decreased to the west (NE). However, local factors alone were unable to explain lower production in NE than IA for locations with similar properties. Landscape features, such as large alluvial plains that reduced connectivity by wind, were more important than local factors to explain different responses along the gradient during the drought. These findings have important implications for landscape configurations and connectivity in the face of large-scale, extreme events.

}, author = {Debra C. Peters and N. Dylan Burruss and Gregory S. Okin and J. Hatfield and Colby Brungard} } @article {JRN55136, title = {A comparison of soil texture-by-feel estimates: Implications for the citizen soil scientist}, journal = {Soil Science Society of America}, volume = {82}, year = {2018}, month = {08/2018}, pages = {1526-1537}, chapter = {1526}, abstract = {

Estimating soil texture is a fundamental practice universally applied by soil scientists to classify and understand the behavior, health, and management of soil systems. While the accuracy of both the soil texture class and the estimates of percent sand and clay is generally accepted when completed by trained soil scientists, similar estimates by {\textquotedblleft}citizen scientists{\textquotedblright} or inexperienced seasonal resource scientists are often questioned. We compared soil texture classes determined by texture-by-feel and laboratory analyses for 2 groups: professional soil scientists who contributed to the USDA-NRCS National Soil Characterization Database and seasonal field technicians working on rangeland inventory and assessment programs in the Western United States and Namibia. Texture accuracy was compared using a confusion matrix to evaluate classification accuracy based on the assumption that laboratory measurements were correct. Our results show that the professional soil scientists predicted the laboratory-determined texture class for 66\% of the samples. Accuracy for seasonal field technicians was between 27\% and 41\%. When a {\textquotedblleft}correct{\textquotedblright} prediction was defined to include texture classes adjacent to the laboratory-determined texture based on a standard USDA texture triangle, accuracy increased to 91\% for professionals and 71\% to 78\% for seasonal field technicians. These findings highlight the need to improve options for increasing the accuracy of field-textured estimates for all soil texture observers, with relevance to career soil scientists, seasonal technicians, and citizen scientists. Opportunities for improving soil texture accuracy include training, calibration, and decision support tools that go beyond simple dichotomous keys.

}, doi = {doi:10.2136/sssaj2018.04.0137}, url = {files/bibliography/18-019.pdf}, author = {S. W. Salley and Jeffrey E. Herrick and Holmes, Caitlin and Jason W. Karl and Matthew Levi and Sarah McCord and Cornelis Van De Waal and Justin Van Zee} } @conference {JRN54914, title = {Can heritage cattle protect ecosystems and economies in the changing rangelands of the western United States?}, booktitle = {Ecological Society of America}, year = {2018}, month = {08/2018}, publisher = {Ecological Society of America}, organization = {Ecological Society of America}, address = {New Orleans, LA}, abstract = {

Pastoralism may be our best bet for preserving biodiversity and soil carbon in the rangelands of the western United States. Early grazing practices triggered persistent ecological transitions in many US rangelands, but going forward, maintaining these lands as semi-natural systems with opportunities for restoration ultimately relies on sustainable ranching that serves as a bulwark against development to more intensive uses. Yet for ranching to be sustainable, it must simultaneously achieve multiple targets: economic profitability, environmental quality, and social connectivity. Climate change complicates chances for achieving these sustainability targets. For instance, rangelands in the southwestern United States are projected to become hotter and drier with greater variability in annual precipitation and later onset of monsoon rains, and the sustainability of desert ranching will depend on its ability to adapt to these emerging conditions. An adaptation strategy gaining momentum entails raising drought-adapted, low-input beef cattle biotypes. In the Chihuahuan Desert of Texas-New Mexico-Mexico, a number of studies are underway to assess whether ranching with Raramuri Criollo, a heritage biotype with 500 years of evolution in nearby harsh desert environments, may provide viable options for pastoral communities as conditions change. Evidence from four independent studies suggests that heritage Raramuri Criollo differ from conventional breeds (i.e., Angus crossbreds) with regard to use of large desert pastures. When vegetation is greener and more abundant, the two types exhibit similar spatial distribution and landscape use patterns. Conversely, when forage is scarce, the heritage cattle traverse greater distances, and farther from water, to access forage. These different seasonal use patterns have different implications for ranch economics as well as for desert soils and vegetation. Further, hourly movement patterns suggest that the heritage breed has a higher tolerance for hot summer temperatures, which could translate into expanded opportunities for pastoralism in a warming climate. Importantly, one option for producing the heritage cattle entails grass finishing, with economics and environmental footprint differing from that of conventional production, which involves grain-finishing hundreds of kilometers away. Improved estimates of environmental and economic outcomes of the conventional and alternative production systems would enhance understanding of ecosystem service flows under the two systems, which could ultimately inform policies that incentivize adoption of the heritage breed. This talk will review preliminary findings of the research program and implications for sustainable ranching in the changing rangelands of the western United States.

}, author = {S. Spiegal and Richard E. Estell and Andr{\'e}s F. Cibils and Amy L. Gonzalez and McIntosh, William C. and S. Nyamuryekung{\textquoteright}e and Brandon T Bestelmeyer} } @conference {JRN54911, title = {Communicating Ecological Data with Land Managers: Lessons Learned}, booktitle = {Ecological Society of America}, year = {2018}, month = {08/2018}, publisher = {Ecological Society of America}, organization = {Ecological Society of America}, address = {New Orleans, LA}, abstract = {

Communicating ecological data to land managers and management entities represents a different challenge than communicating with the general public. Land managers need to not only understand results but also the inherent limits and assumptions in order to make effective and legally defensible decisions. However, many face barriers to producing or interpreting results of data analysis including time, resources, and technical skills. Our group, a partnership between the USDA Agricultural Research Service (ARS), the National Aquatic Monitoring Center (NAMC), and the Bureau of Land Management (BLM), has been working on the BLM Assessment, Inventory, and Monitoring Strategy (AIM) since 2010. The purpose of AIM is to provide land managers with robust, high quality monitoring data gathered with consistent methods and statistically-sound sampling techniques. Through this effort, we have experienced both successes and failures in communicating data to land managers.
As a result, our data communication has necessarily evolved. We refined the amount of data, their format, and the kinds of results and delivery mechanisms. This process has required working iteratively with land managers to identify what analyses and data visualizations are useful and how to make them as accessible as possible. Results/Conclusions: Based on feedback from users and observing how data have been applied, we have arrived at general principles for communicating data to land managers. We find that starting with conversation about users{\textquoteright} analysis objectives and existing decision-making workflows that use the results often shapes data requests. High density, high complexity figures are less likely to be impactful; we try to consistently produce simple, direct figures which display only one kind of result. Land managers often find graphical figures easier to draw general conclusions from, but may need tabular results for documentation; we provide equivalent data in multiple formats which can be integrated into different analyses. We aim to present statistics in ways that users can interrogate and discuss as part of interpretation; this is especially important for statistics like uncertainty that users may have intuitive rather than formal understandings of.Our conclusions are shaped by direct feedback from land managers regarding what helps and hinders their use of AIM data. We will continue refining our approaches through workshops with the community of practice of land managers who are using the data.

}, author = {Nelson Stauffer and Sarah McCord and Emily Kachergis} } @article {JRN54927, title = {Cascading impacts of climate change on southwestern US cropland agriculture}, journal = {Climatic Change}, volume = {148}, year = {2018}, month = {05/2018}, pages = {437-450}, chapter = {437}, abstract = {

The interior southwest United States is one of the hottest, driest regions on the planet, yet irrigated cropland agriculture is successfully practiced where there is access to surface water and/or groundwater. Through climate change, the southwest is projected to become even hotter and drier, increasing the challenges faced by farmers across the region. We can assess the vulnerability of cropland agriculture, to assist in developing potential solutions to these challenges of warming temperatures and water scarcity. However, these types of biophysical vulnerability assessment usually generate technological or policy-level solutions that do not necessarily account for farmers{\textquoteright} ability to respond to climate change impacts. Further, there are non-climatic factors that also threaten the future of agriculture in the region, such as population increase, loss of agricultural land, and increasing competition for depleting water resources. In this paper, we assert that to fully address how southwestern farmers may respond to climate change impacts, we must consider both biophysical outcome and contextual vulnerabilities. Future research on individual localities and/or specific commodities and including cross-disciplinary analysis of socio-economic, institutional, cultural, and political factors alongside biophysical factors will help to develop more substantive understanding of system vulnerabilities and feasible adaptive solutions.

}, doi = {doi.org/10.1007/s10584-018-2220-4}, url = {files/bibliography/18-010.pdf}, author = {Caitriana Steele and J.T. Reyes and Emile H. Elias and Sierra Aney and A. Rango} } @article {JRN54810, title = {Comparison of Near Infrared Reflectance Spectroscopy and Raman Spectroscopy for Predicting Botanical Composition of Cattle Diets}, journal = {Rangeland Ecology and Management}, volume = {70}, year = {2017}, month = {10/2017}, pages = {781-786.}, chapter = {781}, abstract = {

Diet selection is an important driver of ecosystem structure and function that is difficult to measure. Because of advances in spectroscopy new instruments are available for evaluating their applicability to ecological field studies. \ The objective of this study was to compare near infrared reflectance spectroscopy (NIRS) to Raman spectroscopy of fecal samples for predicting the percentage of Honey mesquite (Prosopis glandulosa Torr.) in the diet of ruminally fistulated cattle fed three different base hay diets and to compare them for their ability to discriminate among the three base diets. Spectra were collected from fecal materials from a feeding trial with mesquite fed at 0, 1, 3 and 5\% of the diet and base hay diets of timothy hay (Phleum pratense L.), Sudan hay (Sorghum sudanense (Piper) Stapf), or a 50:50 combination of Bermudagrass hay (Cynodon dactylon (L.) Pers.) and beardless wheat hay (Triticum aestivum L.). NIRS and Raman spectra were used for partial least squares regression calibrations with the timothy and Sudan hays and validated with the Bermudagrass beardless wheat hay diets. NIRS spectra provided useful calibrations (r2=0.88, slope=1.03, intercept=1.88, root mean square error=2.09, bias=1.95, ratio of performance to deviation=2.6), but Raman spectra did not. Stepwise discriminant analysis was used to select wavenumbers for discriminant among the three hays. Fifteen of 350 possible wavenumbers for NIRS spectra and 29 of 300 possible wavenumbers for Raman spectra met the P=0.05 entry and staying criteria. Canonical discriminant analysis using these wavenumber resulted in 100\% correct classification for all three base diets and the Raman spectra provided greater separation than NIRS spectra. \ Discrimination using Raman spectra was primarily associated with wavenumbers associated with undigestible constituents of the diet, i.e., lignin. In contrast, discrimination using f.NIRS spectra was primarily associated with wavenumbers associated with digestible constituents in the diet, i.e., protein, starch and lipid. We believe that Raman spectroscopy deserves further investigation as a quantitative technique in ecological field studies.

}, doi = {10.1016/j.rama.2017.06.008}, url = {files/bibliography/17-024.pdf}, author = {Altangerel, N and J.W. Walker and Piedad Mayagoitia and C. Donovan Bailey and Richard E. Estell and Scully, M} } @conference {JRN54805, title = {A conceptual model of agroecosystem function as a basis for synthesis}, booktitle = {Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting}, year = {2017}, month = {10/2017}, publisher = {Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting}, organization = {Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting}, address = {Tampa, Florida}, abstract = {

A primary challenge for LTAR is to organize information about sustainable agricultural intensification such that it can be synthesized across multiple research programs addressing disparate problems. Such synthesis facilitates not only regional to national-scale generalizations to inform the public and policy, but also provides a platform for agricultural researchers to collaborate, learn from one another{\textquoteright}s research traditions and tools, and identify previously unrecognized research needs. In this talk, we describe a conceptual model of agroecosystem function that identifies fundamental interactions between agriculture, environment, and society. The model focuses on agricultural producers and their decisions in selecting a production system. Feedback loops mediated by environmental effects, economics, societal factors, and policies can reinforce the status quo or prompt producers to adopt an alternative production system. External shocks (drivers and perturbations that are unaffected by feedbacks) can also tip the system into alternative production states. The model was used effectively as a basis for organizing interactions within production systems into questions and predictions. These questions served as the basis for an LTAR-wide survey and synthesis described in a companion talk.

}, author = {Brandon T Bestelmeyer and S. Spiegal and Timothy Strickland and Hilary Swain and Elizabeth H. Boughton} } @article {JRN54777, title = {Coping with historic drought in California rangelands: Developing a more effective institutional response}, journal = {Rangelands}, volume = {39}, year = {2017}, month = {04/2017}, chapter = {73}, abstract = {

Drought response is widely varied, depending on both the characteristics of the drought and the ability of individual ranchers to respond. \ Assistance from institutions during drought has not typically considered preemptive, during and post-drought response as a strategic approach which recognizes biophysical, sociological and economic complexities of drought. A USDA SW Climate Hub sponsored workshop brought together a range of representatives from institutions with drought response responsibilities to examine how those institutions could better support drought decision making.

}, doi = {doi:10.1016/j.rala.2017.01.002.}, url = {files/bibliography/17-014.pdf}, author = {Joel R. Brown and Alvarez, Pelayo and Byrd, Kristen and Helena Deswood and Emile H. Elias and S. Spiegal} } @proceedings {JRN54678, title = {A comparison of two vegetation height measurement methods for applications to sage grouse habitat evaluations}, volume = {Jan 29 - Feb 02, 2017}, year = {2017}, month = {01/2017}, address = {Saint George, Utah}, abstract = {

The conservation of Greater Sage-Grouse (Centrocercus urophasianus) habitat has become a serious management issue for U.S. federal land agencies given competing land uses and ecological change across the American West. This drives a need for data collection in Sage-Grouse habitat to assess habitat condition in a consistent manner. The 2015 Sage-Grouse Habitat Assessment Framework (HAF), describes site-scale habitat suitability for Sage-grouse seasonal habitats, in part, by height of sagebrush and perennial grasses and forbs. The height method described in the HAF (average of maximum plant heights) is different from the core vegetation height method (average of maximum plant heights within a series of fixed-radius cylinders) adopted by the BLM{\textquoteright}s Assessment, Inventory, and Monitoring (AIM) program and the NRCS{\textquoteright}s National Resources Inventory. Given the widespread implementation of the core methods, there may be benefits to using these data to complete habitat suitability assessments for Sage-Grouse. We compared the HAF and core height methods for shrubs, forbs, and grasses to evaluate if the core height method could be used to characterize Sage-Grouse habitat, using data from sites across the western U.S. where both methods were applied at each survey plot. We found a positive correlation between herbaceous and woody heights at the plot level. Individual within-plot measurements had a weaker correlation due largely to differences in which plants were measured with each method. We observed that the core method underestimated height compared to HAF as expected based on measured plant component. Simulations of the two height methods confirmed that, although they measure different indicators, the two indicators are strongly correlated. We therefore conclude that core vegetation height data are compatible with HAF habitat suitability evaluation. Where core data are already being gathered, we recommend using the core vegetation height method to satisfy HAF habitat suitability evaluations instead of collecting additional height measurements.

}, author = {Sean F. Di Stefano and Nelson Stauffer and Jason W. Karl and Sarah McCord} } @article {JRN54848, title = {Comment on {\textquotedblleft}The extent of forest in dryland biomes{\textquotedblright}}, journal = {Science}, volume = {358}, year = {2017}, pages = {3 pp}, abstract = {

Bastin et al. (Reports, 12 May 2017, p. 635) infer forest as more globally extensive than previously estimated using tree cover data. However, their forest definition does not reflect ecosystem function or biotic composition. These structural and climatic definitions inflate forest estimates across the tropics and undermine conservation goals, leading to inappropriate management policies and practices in tropical grassy ecosystems.

}, doi = {10.1126/science.aao1309}, author = {Griffith, Daniel M. and Lehmann, Caroline E. R. and Str{\"o}mberg, Caroline A. E. and Parr, Catherine L. and Pennington, R. Toby and Sankaran, Mahesh and Ratnam, Jayashree and Still, Christopher J. and Powell, Rebecca L. and Niall Hanan and Jesse Nippert and Osborne, Colin P. and Good, Stephen P. and T. Michael Anderson and Holdo, Ricardo M. and Veldman, Joseph W. and Durigan, Giselda and Tomlinson, Kyle W. and Hoffmann, William A. and Archibald, Sally and Bond, William J.} } @article {JRN54662, title = {A comparison of cover calculation techniques for relating point-intercept vegetation sampling to remote sensing imagery}, journal = {Ecological Indicators}, volume = {73:156-165}, year = {2017}, month = {01/2017}, abstract = {
Accurate and timely spatial predictions of vegetation cover from remote imagery are an important data source for natural resource management. High-quality in situ data are needed to develop and validate these products. Point-intercept sampling techniques are a common method for obtaining quantitative information on vegetation cover that have been widely implemented in a number of local and national monitoring programs. The use of point-intercept data in remote sensing projects, however, is complicated due to differences in how vegetation cover indicators can be calculated. Decisions on whether to use plant intercepts from any canopy layer (i.e., any-hit cover) or only the first plant intercept at each point (i.e., top-hit cover) can result in discrepancies in cover estimates which are used to train remotely-sensed imagery. Our objective in this paper was to explore the theory of point-intercept sampling relative to training and testing remotely-sensed imagery, and to test the strength of relationships between top-hit and any-hit methods of calculating vegetation cover and high-resolution satellite imagery in two study areas managed by the Bureau of Land Management in northwestern Colorado and northeastern California. We modeled top-hit and any-hit percent cover for six vegetation indicators from 5m-resolution RapidEye imagery using beta regression. Model performance was judged using normalized root mean-squared error (RMSE) from a 5-fold cross validation. Any-hit cover estimates were significantly higher (a \< 0.05) than top-hit cover estimates for forbs and grasses in the White River study area, but only marginally higher in Northern California. Pseudo-R2 values for beta regression models of vegetation cover from RapidEye image information varied from 0.1045 to 0.7681 in White River and 0.2143 to 0.5775 in Northern California, with little pattern to whether any-hit or top-hit indicators produced better model fit. However, in all cases except for annual forbs in Northern California, normalized RMSE was lower for any-hit cover indicators indicating better model performance, though for some indicators the difference was minimal. Our results do not support the idea that top-hit cover estimates from point-intercept sampling are the most appropriate for remote sensing applications in arid and semi-arid shrub-steppe environments. In fact, having two sets of different indicators calculated from the same data may cause additional confusion in a situation where there is already considerable debate on how vegetation cover should be measured and used. Ultimately, selection of indicators to use for developing remote sensing classification or predictive models should be based first on the meaning or interpretation of the indicator, and second on how well the indicator performs in modeling applications.\ 
}, doi = {10.1016/j.ecolind.2016.09.034}, url = {files/bibliography/17-004.pdf}, author = {Jason W. Karl and Sarah McCord and Hadley, Brian} } @proceedings {JRN54782, title = {Can dust emission mechanisms be determined from field measurements?}, volume = {[abstract]}, year = {2017}, month = {04/2017}, publisher = {European Geosciences Union General Assembly}, address = {Vienna, Austria}, abstract = {

Field observations are needed to develop and test theories on dust emission for use in dust modeling systems. The dust emission mechanism (aerodynamic entrainment, saltation bombardment, aggregate disintegration) as well as the amount and particle-size distribution of emitted dust may vary under sediment supply- and transport-limited conditions. This variability, which is caused by heterogeneity of the surface and the atmosphere, is not currently fully captured in either field measurements or models. \ However, uncertainty in dust emission modeling can be reduced through more detailed observational data on the dust emission mechanism itself. To date, most measurements do not provide enough information to allow for a determination of the mechanisms leading to dust emission and often focus on a small variety of soil and atmospheric settings. Additionally, data sets are often not directly comparable due to different measurement setups. As a consequence, the calibration of dust emission schemes has relied on a selective set of observations, which leads to an idealization of the emission process in models and thus affects dust budget estimates. Here, we will present preliminary results of a study which aims to decipher the dust emission mechanism from field measurements as an input for future model development. Detailed field measurements are conducted, which allow for a comparison of dust emission for different surface and atmospheric conditions. Measurements include monitoring of the soil surface, loose erodible material, transported sediment, and meteorological data, and are conducted in different environmental settings in the southwestern United States. Based on the field measurements, a method is developed to differentiate between the different dust emission mechanisms.

}, author = {Martina Klose and Nicholas Webb and Thomas E. Gill and Scott Van Pelt and Gregory S. Okin} } @conference {JRN54671, title = {Completing the land resource hierarchy}, booktitle = {Society for Range Management}, volume = {Jan 29 - Feb 02, 2017}, year = {2017}, month = {01/2017}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Saint George, Utah}, abstract = {

The Land Resource Hierarchy of the NRCS is a hierarchal landscape classification consisting of resource areas which represent both conceptual and spatially discrete landscape units stratifying agency programs and practices. The Land Resource Hierarchy (LRH) scales from discrete points (soil pedon and vegetation patch) up to broad continental climate zones (Land Resource Regions). \ Inclusion of Ecological Sites into the LRH has renewed interest in strengthening the concepts behind the NRCS{\textquoteright}s landscape classification system which ultimately will lead to revisions of Agriculture Handbook $\#$296 and updates to Major Land Resource Areas. In this paper we identify knowledge gaps and provide recommendations to complete the Land Resource Hierarchy and the subsequent landscape classification mapping updates. For example, one major inconsistency of the LRH occurs at the mid-scales of the hierarchy, specifically the Ecological Site Groups, Land Resource Units, and Major Land Resource Areas. These middle category scales in the hierarchy currently lack strong guidance and policy required for a consistent national and scientifically defensible product. To strengthen the hierarchical model of the LRH, we recommend that respective scales in the hierarchy be defined by ecosystem components at spatial and temporal scales which reflect relevant ecological dynamics. Furthermore, each focal level in the hierarchy should be constrained by only the immediate up-scale resource area (which provides context, significance, and boundary conditions) and subsequently tested by only the immediate down-scale resource area (which gives specificity, explains, and provides mechanisms delineating the resource area). Adopting a combined top-down and bottom-up approach limited to the focal scale of interest is important as ecosystem processes operate at different temporal and spatial scales and often demonstrate cross-scale interactions that a limited scaled-up or scaled-down only system fails to identify.

}, author = {S. W. Salley and Curtis Talbot and Joel R. Brown} } @conference {JRN54780, title = {Comparison of diet selection by Raramuri criollo and Angus crossbreds in the Chihuahuan Desert}, booktitle = {American Society of Animal Science}, year = {2017}, month = {07/2017}, publisher = {American Society of Animal Science}, organization = {American Society of Animal Science}, address = {Baltimore, MD}, abstract = {

Raramuri Criollo (RC) is a cattle biotype that has undergone natural selection for the past 500 years in northern Mexico. No information exists on diet selection for this biotype. The objective of this study was to compare diet selection of RC and Angus x Hereford crossbreds (AH) typically found in the arid southwestern United States. We examined dietary composition of RC and AH cattle using DNA metabarcoding of fecal samples. Ten mature cows of each breed grazed two adjacent pastures (1190 ha, 1165 ha) for 28 days in July-August 2015 and January-February 2016 in a crossover design. Each breed grazed each pasture 14 days per period and cows were then switched to the reciprocal pasture. Fecal samples were collected on day 14 in each pasture in both seasons. Dominant species present in fecal samples included black grama (Bouteloua eriopoda), tobosa (Pleuraphis mutica), plains bristlegrass (Setaria leucopila), hog potato (Hoffmannseggia glauca), and four-wing saltbush (Atriplex canescens). Black grama was present in higher concentration in AH than RC fecal samples (P \< 0.0001) and was greater during winter dormancy than during the summer growing season (P \< 0.0001). Hog potato was not affected by breed (P = 0.137) but was greater in fecal samples during the growing season than during winter dormancy (P \< 0.001). Four-wing saltbush was marginally greater in AH than RC fecal samples (P = 0.053) and greater during dormancy than in the growing season (P \< 0.0001). These results suggest that RC cattle select diets that differ from AH cows and that differences are affected by plant growth phenology.

}, author = {S. Spiegal and S. Nyamuryekung{\textquoteright}e and Richard E. Estell and Andr{\'e}s F. Cibils and Matthew M. McIntosh and Amy L. Gonzalez and D. K. James} } @article {JRN54627, title = {Climate change, agriculture and water resources in the Southwestern United States}, journal = {Journal of Contemporary Water Research and Education}, year = {2016}, month = {08/2016}, pages = {46-61}, abstract = {

In February 2014 the USDA established regional climate hubs across the United States to assist farmers, ranchers and foresters in adapting to the effects of climate change. The Southwest (SW) region encompasses six states which provide highly diverse agricultural crops including cotton, stone fruit and grapes. Here we report on the establishment of programs to assist SW working landowners with the impacts of climate change, with focus on the water resources of the region. Water is a critical component of agricultural vulnerability in the SW, where high agricultural production can occur with sufficient irrigation. Since 1978, crop yield declines were reported on 11-21\% of total irrigated acres, mostly due to surface water shortage. Southwestern agriculture relies heavily on groundwater, using it to supply more than one-third of the agricultural water demand since 1955. Regional groundwater use varies over time, with a decline in the agricultural groundwater fraction in Arizona, but an increase in the fraction in Nevada and Utah. Observed and predicted changes in the southwestern hydrologic cycle can impact regional agriculture. Observed records show an increase in the fraction of precipitation falling as rain, which is expected to continue with future warming. Warming causes the snowmelt to peak earlier in the season and can reduce water available to crops during the summer months without additional water storage. Observed records indicate streamflow has shifted earlier in the year, most notably in snow dominated watersheds a continuation of this trend may challenge regional agriculture by further limiting water supply.

}, keywords = {agriculture, climate change, Southwest Climate Hub, water resources}, url = {files/bibliography/16-017.pdf}, author = {Emile H. Elias and A. Rango and Ryann Smith and Connie J. Maxwell and Caitriana Steele and Kris Havstad} } @conference {JRN54515, title = {Connecting long-term monitoring data from vegetation plots and remote sensing in the Southwestern USA }, booktitle = {69th Society for Range Management Annual Meeting}, year = {2016}, month = {01/2016}, publisher = {Society for Range Mangement}, organization = {Society for Range Mangement}, address = {Corpus Christi, TX}, abstract = {

Understanding vegetation response to changing climate patterns is an important element of rangeland management and supports the use and development of ecological site descriptions. Monitoring of rangeland conditions with remote sensing can be misleading if ground measurements are not used to interpret changes in vegetation indices. We used a 25 year time series of Landsat normalized difference vegetation index (NDVI) to evaluate vegetation dynamics in the Malpai Borderlands Area of Arizona and New Mexico(~324,000 ha). The NDVI time series was decomposed into trend and seasonal variability to better understand spatial and temporal changes in vegetation dynamics across the region. Long-term vegetation monitoring plots and soil profile descriptions provided ground-based information to interpret patterns of NDVI. Monthly PRISM climate data were also used to interpret NDVI and vegetation dynamics. We compared changes in percent cover of plant functional types on a five year interval to the decomposed time series between measurements to elucidate causes of NDVI variability. Management practices across the time period are largely unknown; hence our interpretations reflect variable climate patterns and the effect of fires in the region. Preliminary results indicate a decrease in perennial grass cover in 2003 following a period of extreme regional drought . Perennial grass cover at most plots rebounded to pre-drought conditions or more perennial grass cover by 2008; however, some did not. We will present a detailed analysis of NDVI trends across the region and directly link changes in measured cover at monitoring locations to changes in NDVI and precipitation. Connecting NDVI time series data to point locations of measured cover values will advance interpretations of remotely sensed imagery for broad-scale assessments of rangeland condition and facilitate improved ecological site interpretation.

}, author = {Matthew Levi and Brandon T Bestelmeyer} } @conference {JRN54634, title = {Complex landscapes in the American Southwest: Under what conditions does desetification lead to novel ecosystems?}, booktitle = {2016 Ecological Society of America Meetings}, year = {2016}, month = {08/2016}, publisher = {Ecological Society of America Abstracts}, organization = {Ecological Society of America Abstracts}, address = {Ft Lauderdale, FL}, abstract = {
Novel ecosystems are often defined as no-analog communities consisting of new combinations of species that assemble under new abiotic conditions. In the Anthropocene, novel systems differ from the historical state as a result of human influences where self-organizational processes prevail to make these ecosystems unlikely to revert to their historical structure/function. Degraded shrub-dominated ecosystems that develop following livestock overgrazing and drought in arid and semiarid grasslands are a potential example of novel ecosystems. Although the self-organization and stability of desertified ecosystems have been well-studied, these ecosystems have not been tested as novel ecosystems. Our objective was to test novel ecosystem concepts and hypotheses across complex landscapes at a 78,000 ha research site established in 1912 to examine the causes and consequences of desertification. We integrated long-term vegetation maps dating to 1850 with USDA data on grazing, drought, and species composition (1915 onward), and a suite of LTER data on biotic and abiotic patterns and processes (1982-present) for the Jornada Basin LTER-USDA site in southern New Mexico, USA. We hypothesized that degraded ecosystems dominated by different grass-shrub assemblages represent novel ecosystems if they meet each of four criteria: 1. different from past states, 2. human-driven, 3. self-organized, and 4. irreversible.\ 
All four criteria were met for some locations for each degraded shrubland type (mesquite, creosotebush, tarbush), yet not all locations were identified as novel. Because these shrub species are native to the region, an expansion of a species beyond its native habitat is needed for novelty to be recognized. Our synthesis shows that this expansion was initiated by human drivers, but then for some locations a change in soil properties occurred through time that led to a shift in species dominance and composition and further changes in soil properties. These shifts were maintained by plant-soil feedbacks and self-organization to result in novel ecosystems. On other locations, a localized spatial redistribution of soil and nutrients among grasses and shrubs within the ecosystem occurred that led to a state change, but not a novel ecosystem. Thus, arid landscapes are complex mosaics of historic grass remnants, degraded yet native shrublands, and degraded and novel shrublands. The dynamic soil-geomorphic template interacting with species characteristics is another layer of complexity that needs to be accounted for when predicting future dynamics of arid landscapes that contain novel ecosystems.
}, author = {Debra C. Peters and Steven R. Archer and O. E. Sala and Kris Havstad and Enrique Vivoni and Gregory S. Okin} } @article {JRN54606, title = {Completing the land resource hierarchy}, journal = {Rangelands}, volume = {38}, year = {2016}, month = {12/2016}, chapter = {313}, abstract = {

The Land Resource Hierarchy of the NRCS is a hierarchal landscape classification consisting of resource areas which represent both conceptual and spatially discrete landscape units stratifying agency programs and practices. The Land Resource Hierarchy (LRH) scales from discrete points (soil pedon and vegetation patch) up to broad continental climate zones (Land Resource Regions). \ Inclusion of Ecological Sites into the LRH has renewed interest in strengthening the concepts behind the NRCS{\textquoteright}s landscape classification system which ultimately will lead to revisions of Agriculture Handbook $\#$296 and updates to Major Land Resource Areas. In this paper we identify knowledge gaps and provide recommendations to complete the Land Resource Hierarchy and the subsequent landscape classification mapping updates. For example, one major inconsistency of the LRH occurs at the mid-scales of the hierarchy, specifically the Ecological Site Groups, Land Resource Units, and Major Land Resource Areas. These middle category scales in the hierarchy currently lack strong guidance and policy required for a consistent national and scientifically defensible product. To strengthen the hierarchical model of the LRH, we recommend that respective scales in the hierarchy be defined by ecosystem components at spatial and temporal scales which reflect relevant ecological dynamics. Furthermore, each focal level in the hierarchy should be constrained by only the immediate up-scale resource area (which provides context, significance, and boundary conditions) and subsequently tested by only the immediate down-scale resource area (which gives specificity, explains, and provides mechanisms delineating the resource area). Adopting a combined top-down and bottom-up approach limited to the focal scale of interest is important as ecosystem processes operate at different temporal and spatial scales and often demonstrate cross-scale interactions that a limited scaled-up or scaled-down only system fails to identify.

}, doi = {10.1016/j.rala.2016.10.003}, url = {files/bibliography/16-028.pdf}, author = {S. W. Salley and Curtis H. Monger and Joel R. Brown} } @conference {JRN54615, title = {Completing the land resource hierarchy}, booktitle = {Soil Science Society of America Annual Meeting}, year = {2016}, month = {11/2016}, publisher = {Soil Science Society of America}, organization = {Soil Science Society of America}, address = {Phoenix, AZ}, abstract = {

The Land Resource Hierarchy of the NRCS is a hierarchal landscape classification consisting of resource areas which represent both conceptual and spatially discrete landscape units stratifying agency programs and practices. The Land Resource Hierarchy (LRH) scales from discrete points (soil pedon and vegetation patch) up to broad continental climate zones (Land Resource Regions). \ Inclusion of Ecological Sites into the LRH has renewed interest in strengthening the concepts behind the NRCS{\textquoteright}s landscape classification system which ultimately will lead to revisions of Agriculture Handbook $\#$296 and updates to Major Land Resource Areas. In this paper we identify knowledge gaps and provide recommendations to complete the Land Resource Hierarchy and the subsequent landscape classification mapping updates. For example, one major inconsistency of the LRH occurs at the mid-scales of the hierarchy, specifically the Ecological Site Groups, Land Resource Units, and Major Land Resource Areas. These middle category scales in the hierarchy currently lack strong guidance and policy required for a consistent national and scientifically defensible product. To strengthen the hierarchical model of the LRH, we recommend that respective scales in the hierarchy be defined by ecosystem components at spatial and temporal scales which reflect relevant ecological dynamics. Furthermore, each focal level in the hierarchy should be constrained by only the immediate up-scale resource area (which provides context, significance, and boundary conditions) and subsequently tested by only the immediate down-scale resource area (which gives specificity, explains, and provides mechanisms delineating the resource area). Adopting a combined top-down and bottom-up approach limited to the focal scale of interest is important as ecosystem processes operate at different temporal and spatial scales and often demonstrate cross-scale interactions that a limited scaled-up or scaled-down only system fails to identify.

}, author = {S. W. Salley and Joel R. Brown and Curtis H. Monger} } @article {JRN54500, title = {Closing the water balance with cosmic-ray soil moisture measurements and assessing their relation to evapotranspiration in two semiarid watersheds}, journal = {Hydrology and Earth System Sciences}, volume = {20}, year = {2016}, month = {01/2016}, pages = {329-345}, chapter = {329}, abstract = {

Soil moisture dynamics reflect the complex interactions of meteorological conditions with soil, vegetation and terrain properties. In this study, intermediate-scale soil moisture estimates from the cosmic-ray neutron sensing (CRNS) method are evaluated for two semiarid ecosystems in the southwestern United States: a mesquite savanna at the Santa Rita Experimental Range (SRER) and a mixed shrubland at the Jornada Experimental Range (JER). Evaluations of the CRNS method are performed for small watersheds instrumented with a distributed sensor network consisting of soil moisture sensor profiles, an eddy covariance tower, and runoff flumes used to close the water balance. We found a very good agreement between the CRNS method and the distributed sensor network (root mean square error (RMSE) of 0.009 and 0.013m3 m-3 at SRER and JER, respectively) at the hourly timescale over the 19-month study period, primarily due to the inclusion of 5 cm observations of shallow soil moisture. Good agreement was also obtained in soil moisture changes estimated from the CRNS and watershed water balance methods (RMSE of 0.001 and 0.082m3 m-3 at SRER and JER, respectively), with deviations due to bypassing of the CRNS measurement depth during large rainfall events. Once validated, the CRNS soil moisture estimates were used to investigate hydrological processes at the footprint scale at each site. Through the computation of the water balance, we showed that drier-than-average conditions at SRER promoted plant water uptake from deeper soil layers, while the wetter-than-average period at JER resulted in percolation towards deeper soils. The CRNS measurements were then used to quantify the link between evapotranspiration and soil moisture at a commensurate scale, finding similar predictive relations at both sites that are applicable to other semiarid ecosystems in the southwestern US.

}, keywords = {cosmic ray neutron sensing, COSMOS, CRNS method, Jornada Experimental Range, Santa Rita Experimental Range, soil moisture}, doi = {10.5194/hess-20-329-2016}, url = {/files/bibliography/16-004.pdf}, author = {A. P. Schreiner-McGraw and Enrique Vivoni and Mascaro, G. and Franz, T. E.} } @conference {JRN54620, title = {Can foraging behavior of Criollo cattle help increase agricultural production and reduce environmental impacts in the arid Southwest?}, booktitle = {Ecological Society of America}, year = {2016}, month = {08/2016}, publisher = {Ecological Society of America}, organization = {Ecological Society of America}, abstract = {
The Longterm Agroecosystem Research Network (LTAR) was formed to help the nation{\textquoteright}s agricultural systems simultaneously increase production and reduce environmental impacts. Eighteen networked sites are conducting a Common Experiment to understand the environmental and economic problems associated with {\textquotedblleft}business as usual{\textquotedblright} (BAU) agricultural systems and explore hypotheses about how aspirational systems can overcome those problems. In the American Southwest, BAU comprises lightly to moderately stocked cow-calf operations, typically with Angus crossbreds (AX). AX tend to utilize the landscape unevenly. When droughts occur, they may have difficulty accessing sufficient forage, and expensive and resourceintensive supplemental feed is then required. Destocking is a typical coping strategy. We hypothesize that Raramuri Criollo (RC) cattle, which have persisted in arid, rugged conditions in Mexico for ~500 years with minimal husbandry, utilize the landscape more widely {\textendash} and therefore can sustain droughts with little to no supplemental feed. Many questions must be answered about RC production systems. In 2008, we used GPS collars to compare the behavior and landscape utilization of RC and AX in a 1535-ha pasture. We tracked movements across four growing season stages with 5-minute GPS {\textquotedblleft}fix{\textquotedblright} intervals. Using points correlated with foraging, we compared their average daily spatial coverage and resource selection. Preliminary spatial coverage analyses (minimum convex polygon) suggest that in the drier growing season stages, Pregreenup and Drydown, RC foraged over more ground than AX on an average daily basis. Resource selection functions (RSFs) are a general class of functions that predict the probability of use of various resources in a sampling area. Preliminary RSFs estimated using logistic regression suggest that during the drier seasonal stages, the probability that RC will select vegetation types and ecological states with dense honey mesquite is greater than the probability that AX will select those vegetation types and ecological states. Further, in the drier seasonal stages, the likelihood that RC will forage further from permanent watering points is higher than for AX. We did not collect data about direct environmental impacts or agricultural production of the two cattle types during the study; however, a cattle type that forages further from water and selects mesquite patches may help agricultural producers in the arid Southwest weather droughts with less supplemental feed. Many questions remain for the Common Experiment; however, these preliminary results suggest that an agricultural system based on RC may be more likely than "business as usual" to simultaneously increase production and reduce environmental impacts.
}, author = {S. Spiegal and Richard E. Estell and Andr{\'e}s F. Cibils and Dawn M. Browning and H. Raul Peinetti and D. K. James and Kirsten B. Romig and Amy L. Gonzalez} } @article {JRN54667, title = {Carbon sequestration in response to grassland{\textendash}shrubland{\textendash}turfgrass conversions and a test for carbonate biomineralization in desert soils, New Mexico, USA}, journal = {Soil Science Society of America Journal}, volume = {80}, year = {2016}, pages = {1591-1603}, abstract = {

This study uses an experimental pedology approach to examine (i) how the conversion of native C4 grassland to C3 woody shrubs then to irrigated C4 turfgrass affects both soil organic C (SOC) and soil inorganic C (SIC) and (ii) whether SIC can be enhanced by microbial biomineralization. Three sites were studied in the Chihuahuan Desert of New Mexico. At each site, SOC, SIC, and their {\dh}13C values were measured on control soil samples and compared to samples treated with liquid growth medium and Ca(OH)2 at 10 and 40 cm. The treated samples were left to react for 1 mo in February, May, and August of 2014. Using a space-for-time substitution, soil organic C decreased when native grasslands converted to desert shrubs, then sharply increased after desert shrubs were converted to irrigated turfgrass. Most surprising, however, was the increase of SIC in the turfgrass site, which doubled in 6 yr. The {\dh}13C values of both SOC and SIC reflected the change from C4 to C3 then back to C4 vegetation and showed how rapidly SOC and SIC can change their isotopic signatures. Soil inorganic C formation was slightly higher for the liquid growth medium, but no statistically significant differences were observed between the treatments and control samples. In addition, no biomineralization was observed with microscopy, perhaps because the 1-mo reaction time was too short and the amount applied was too small. Although SIC is typically viewed as a soil mineral that requires centuries to accumulate, our study indicate that SIC can be generated in months to years if the soil environment is suitable.

}, keywords = {carbon sequestration, carbonate biomineralization, desert soils, grassland, shrubland, SIC, SOC, soil incorganic carbon, soil organic carbon, turfgrass}, doi = {10.2136/sssaj2016.03.0061}, url = {/files/bibliography/16-038.pdf}, author = {Jiaping Wang and Curtis H. Monger and Wang, Xiujun and Serena, Matteo and Leinauer, Bernhard} } @article {JRN54577, title = {Can ecological land classification increase the utility of vegetation monitoring data?}, journal = {Ecological Indicators}, volume = {69}, year = {2016}, month = {10/2016}, pages = {657-666}, chapter = {657}, abstract = {

Vegetation dynamics in rangelands and other ecosystems are known to be mediated by topoedaphic properties. Vegetation monitoring programs, however, often do not consider the impact of soils and other sources of landscape heterogeneity on the temporal patterns observed. Ecological sites (ES) comprise a land classification system based on soil, topographic, and climate variations that can be readily applied by land managers to classify topoedaphic properties at monitoring locations. We used a long-term (\>40 y) vegetation record from southeastern Arizona, USA to test the utility of an ES classification for refining interpretations of monitoring data in an area of relatively subtle soil differences. We focused on two phenomena important to rangeland management in the southeastern Arizona region: expansion of the native tree velvet mesquite (Prosopis velutina Woot.) and spread of the introduced perennial grassLehmann lovegrass (Eragrostis lehmanniana Nees). Specifically, we sought to determine if a quantitative, ES-specific analysis of the long-term record would (1) improve detection of changes in plant species having heightened ecological or management importance and (2) further clarify topoedaphic effects on vegetation trajectories. We found that ES class membership was a significant factor explaining spatiotem-poral variation in velvet mesquite canopy cover, Lehmann lovegrass basal cover, and Lehmann lovegrass density measurements. In addition, we observed that the potential magnitude of velvet mesquite and Lehmann lovegrass increases varied substantially among ES classes. Our study brings attention to a practical land management tool that might be called upon to increase the effectiveness of vegetation-based indicators of ecosystem change.

}, keywords = {Biological invasion, land classification, monitoring, soil texture, Time series, Vegetation indicator}, doi = {10.1016/j.ecolind.2016.05.030}, url = {/files/bibliography/16-011.pdf}, author = {Jebediah C. Williamson and Brandon T Bestelmeyer and M.P. McClaran and D. Robinett and D.D. Briske and X. Ben Wu and Maria Fern{\'a}ndez-Gim{\'e}nez} } @article {JRN54180, title = {Criollo cattle: Heritage genetics for arid landscapes}, journal = {Rangelands}, volume = {37}, year = {2015}, month = {04/2015}, pages = {62-67}, chapter = {62}, abstract = {

Thirty cows and three bulls from the Chinipas region in the state of Chihuahua, Mexico, were introduced onto the US Department of Agriculture {\textendash} Agricultural Research Service{\textquoteright}s Jornada Experimental Range (JER) in 2005.\  Since then behavioral research has revealed these cattle, most accurately referred to as Raramuri Criollo (RC) cattle, appear well adapted to the harsh and variable climate of the Chihuahuan Desert Ecosystem characterized by abundant woody vegetation and highly variable spatial and temporal precipitation. Observations to date indicate Criollo cattle are thrifty, docile, easy-to-manage, have a long and productive lifespan and require minimal management.\  Research from Arizona suggests Criollo beef is flavorful and equal in tenderness to that of European breeds managed under similar grass-fed production systems.\  The JER is maintaining the pure genetics of RC cattle that have undergone many years of natural selection in Mexico to study their nutritional and behavioral characteristics.\  If these cattle have traits that are desirable in these fragile ecosystems they could have a positive influence on crossbreeding programs for animals destined to dominate arid landscapes.

}, keywords = {dry lands, foraging, livestock, Mexican cattle}, doi = {10.1016/j.rala.2015.01.006}, url = {/files/bibliography/15-010.pdf}, author = {D.M. Anderson and Richard E. Estell and Amy L. Gonzalez and Andr{\'e}s F. Cibils} } @article {JRN54147, title = {Collaboration, interdisciplinary thinking, and communication: new approaches to K{\textendash}12 ecology education}, journal = {Frontiers in Ecology and the Environment}, volume = {13}, year = {2015}, month = {02/2015}, pages = {37-43}, chapter = {37}, abstract = {

Ecologists often engage in global-scale research through partnerships among scientists from many disciplines. Such research projects require collaboration, interdisciplinary thinking, and strong communication skills. We advocate including these three practices as an integral part of ecology education at the kindergarten through 12th grade (K{\textendash}12) level, as opposed to waiting until the graduate level. Current discourse about K{\textendash}12 ecology education focuses on promoting lessons in which students learn science by conducting research rather than simply reading textbooks. Here, we present five models of K{\textendash}12 ecology education programs that emphasize collaboration, interdisciplinary thinking, and communication within student research projects on the ecology of drylands and other ecosystems. Such practices not only provide additional skills for future ecologists but also prepare students for success in any career as well as for ecologically literate citizenship.

}, keywords = {collaboration, communication skills, interdisciplinary thinking, K-12 ecology education}, doi = {10.1890/140130}, url = {/files/bibliography/15-005.pdf}, author = {Stephanie Bestelmeyer and Elser, Monica M. and Spellman, Katie V. and Sparrow, Elena B. and Stephanie Haan-Amato and Keener, Anna} } @conference {JRN54442, title = {Collaborative adaptive landscape management (CALM) in rangelands: Discussion of general principles}, booktitle = {68th Annual Society for Range Management Meeting}, year = {2015}, month = {01/2015}, publisher = {Sociiety for Range Management}, organization = {Sociiety for Range Management}, address = {Sacramento, CA}, abstract = {

The management of rangeland landscapes involves broad spatial extents, mixed land ownership, and multiple resource objectives. Management outcomes depend on biophysical heterogeneity, highly variable weather conditions, land use legacies, and spatial processes such as wildlife movement, hydrological connectivity, and fire that interact with management actions. Given the high level of uncertainty in management responses and the importance of processes at the landscape level, collaborative adaptive management has emerged as an important framework for rangeland stewardship. Collaborative adaptive management emphasizes cooperative planning, learning, and adjustment of actions in response to new knowledge. The term {\textquotedblleft}landscape{\textquotedblright} might usefully be added when cooperation, learning, and implementation involve processes and outcomes at the landscape level (collaborative adaptive landscape management, CALM). There is, however, little synthetic information about the application of CALM in rangelands. In this talk/discussion, we will draw upon core ideas raised during the preceding presentations on CALM projects to identify a set of general principles, tools, and best practices that can help to refine and inspire CALM approaches.

}, author = {Brandon T Bestelmeyer and J.R. Miller} } @article {JRN54275, title = {Climate-change adaptation on rangelands: Linking regional exposure with diverse adaptive capacity}, journal = {Frontiers in Ecology and the Environment}, volume = {13}, year = {2015}, month = {06/2015}, pages = {249-256}, chapter = {249}, abstract = {

The ecological consequences of climate change are predicted to vary greatly throughout US rangelands. \ Projections show warming and drying in the southern Great Plains and the Southwest, warmer and drier summers with reduced winter snowpack in the Northwest, and warmer and wetter conditions in the northern Great Plains. Primarily through their combined effects on soil water availability, these climatic changes will modify plant production and community composition, which will, in turn, affect the livelihoods of humans who rely upon livestock grazing. The ability of rangeland managers to assess risk and prepare for climate change varies greatly and reflects their different adaptive capacities. Geographically specific exposure to climate change and a diverse adaptive capacity to counteract these changes will require development of varied adaptation strategies that can accommodate the various needs and abilities of livestock managers.

}, doi = {10.1890/140266}, url = {/files/bibliography/15-012.pdf}, author = {D.D. Briske and L. A. Joyce and Polley, H. Wayne and Joel R. Brown and Wolter, K. and Jack A. Morgan and McCarl, B.A. and C. Donovan Bailey} } @conference {JRN54503, title = {Coping with historic drought in California rangelands}, booktitle = {California Rangeland Coalition Conference}, year = {2015}, month = {01/2016}, address = {Davis, CA}, abstract = {

The current drought in California is of historic proportion, both in its intensity and its effect on agriculture.\  Although storms of the 2015-16 winter rainfall season have provided modest drought relief, their effects on alleviating the multi-year drought are unknown. Short- and mid-term forecasts are not favorable and generally project an increase in variability as well. Although an increase in seasonal rainfall can be expected to result in increased forage production, the ability of grazing operations to respond at that timescale may be limited by economic constraints.\  The USDA Southwest Regional Climate Hub developed a Rangeland Vulnerability Assessment (VA) for California.\  In an effort to disseminate and implement the findings of the VA, we brought state-level technical and program specialists together with industry leaders to develop strategies for post drought actions that can assist producers in returning to sustainable grazing operations.\  The workshop objectives were to 1) Distribute and discuss the California Rangeland Vulnerability Assessment, and 2) Involve leaders from agencies that provide rangeland financial and technical assistance support to identify agency priorities for implementation of the VA\ .\  The participants identified three areas of major importance as a basis for improving the quality of technical and financial assistance.

}, author = {Joel R. Brown and Alvarez, Pelayo and Helena Deswood and Emile H. Elias and S. Spiegal} } @conference {JRN54400, title = {Climate programs update: USDA Southwest Regional Climate Hub update}, booktitle = {Great Basin Consortium Conference}, year = {2015}, month = {02/2015}, abstract = {

PROGRAM OVERVIEW: The overarching goal of the USDA SW Climate Hub is to assist farmers, ranchers and foresters in addressing the effects of climate change including prolonged drought, increased insect outbreaks and severe wildfires.\  In the first year of operations, the SW Climate Hub (est. February 2014) entered into formal agreements with Cooperative Extension in our 6 states (AZ, CA, HI, NM, NV and UT) to create a network for communication and technology transfer between researchers and stakeholders.The Hub funded a climate change module at the 6th grade level and tested it for expansion to urban and rural schools across the region. Over the past year the Hub authored an assessment of the vulnerability of SW working lands to climate change. The SW Hub and Sub Hub endeavor to partner with other climate-related federal, state and tribal programs in support of resilient and adaptive SW communities.

}, author = {Emile H. Elias} } @article {JRN54225, title = {Characterizing differences in precipitation regimes of extreme wet and dry years: implications for climate change experiments}, journal = {Global Change Biology}, volume = {21}, year = {2015}, pages = {2624-2633}, abstract = {

Climate change is intensifying the hydrologic cycle and is expected to increase the frequency of extreme wet and dry years. Beyond precipitation amount, extreme wet and dry years may differ in other ways, such as the number of precipitation events, event size, and the time between events. We assessed 1614 long-term (100 year) precipitation records from around the world to identify key attributes of precipitation regimes, besides amount, that distinguish statistically extreme wet from extreme dry years. In general, in regions where mean annual precipitation (MAP) exceeded 1000 mm, precipitation amounts in extreme wet and dry years differed from average years by ~40\% and 30\%, respectively. The magnitude of these deviations increased to \>60\% for dry years and to \>150\% for wet years in arid regions (MAP\<500 mm). Extreme wet years were primarily distinguished from average and extreme dry years by the presence of multiple extreme (large) daily precipitation events (events \>99th percentile of all events); these occurred twice as often in extreme wet years compared to average years. In contrast, these large precipitation events were rare in extreme dry years. Less important for distinguishing extreme wet from dry years were mean event size and frequency, or the number of dry days between events. However, extreme dry years were distinguished from average years by an increase in the number of dry days between events. These precipitation regime attributes consistently differed between extreme wet and dry years across 12 major terrestrial ecoregions from around the world, from deserts to the tropics. Thus, we recommend that climate change experiments and model simulations incorporate these differences in key precipitation regime attributes, as well as amount into treatments. This will allow experiments to more realistically simulate extreme precipitation years and more accurately assess the ecological consequences.

}, keywords = {climate change experiments, climate extremes, drought, ecoregions, global patterns, precipitation, rainfall patterns}, doi = {10.1111/gcb.12888}, url = {files/bibliography/JRN00634.pdf}, author = {A. K. Knapp and David L. Hoover and Wilcox, Kevin R. and Avolio, Meghan L. and Koerner, Sally E. and La Pierre, Kimberly J. and Loik, Michael E. and Luo, Yiqi and O. E. Sala and M. D. Smith} } @conference {JRN54410, title = {Considerations for applying digital soil mapping to ecological sites}, booktitle = {2015 National Cooperative Soil Survey National Conference}, year = {2015}, month = {06/2015}, address = {Duluth, MN}, abstract = {

Recent advancements in the spatial prediction of soil properties are not currently being fully utilized for ecological studies. Linking digital soil mapping (DSM) with ecological sites (ES) has the potential to better land management decisions by improving spatial resolution and precision as well as quantifying uncertainty of environmental information. Current spatial representation of ES largely depends on soil survey data. Any discrepancies in soil survey data are carried forward into ES inventories and interpretations. Recent advances in DSM technologies have focused on identifying unique soil components (disaggregating soil map units) and mapping continuous soil properties and associated uncertainty to improve soil data products. Soil surveys often do not discriminate properties important to ecosystem variation because of mapping limitations, yet subtle soil variations within map units or components may have important consequences for vegetation and ecological dynamics. Detailed maps of soil properties linked to important ecological variables could improve explanations of ecosystem patterns and dynamics. A recent workshop was held at the Jornada Experimental Range to bring together NCSS partners experienced with ES and DSM to initiate integration of these efforts. The application of DSM for ecological site development and mapping could help attain goals of the NRCS, BLM and USFS to produce ES products for improved land stewardship. We present a vision of how coupling DSM and ecological site descriptions could change the way we produce and consume ecological information.

}, author = {Matthew Levi and Travis Nauman and Brandon T Bestelmeyer and Joel R. Brown and Colby Brungard and Libohova, Zamir and Danielle Duni and J. Johansen} } @article {JRN54144, title = {Connectivity in dryland landscapes: shifting concepts of spatial interactions}, journal = {Frontiers in Ecology and the Environment}, volume = {13}, year = {2015}, month = {02/2015}, pages = {20-27}, chapter = {20}, abstract = {

Dryland ecosystems are often characterized by patchy vegetation and exposed soil. This structure enhances transport of soil resources and seeds through the landscape (primarily by wind and water, but also by animals), thus emphasizing the importance of connectivity {\textendash} given its relation to the flow of these materials {\textendash} as a component of dryland ecosystem function. We argue that, as with the fertile-islands conceptual model before it, the concept of connectivity explains many phenomena observed in drylands. Further, it serves as an organizing principle to understand dryland structure and function at scales from individual plants to entire landscapes. The concept of connectivity also helps to organize thinking about interactions among processes occurring at different scales, such as when processes at one scale are overridden by processes at another. In these cases, we suggest that state change occurs when fine-scale processes fail to adjust to new external conditions through resource use or redistribution at the finer scale. The connectivity framework has practical implications for land management, especially with respect to decision making concerning the scale and location of agricultural production or habitat restoration in the world{\textquoteright}s drylands.

}, keywords = {conceptual model, dryland landscapes, landscape connectivity, soil transport, spatial interactions, state changes}, doi = {10.1890/140163}, url = {/files/bibliography/15-003.pdf}, author = {Gregory S. Okin and Moreno-de las Heras, Mariano and Patricia M. Saco and Heather L. Throop and Enrique Vivoni and A.J. Parsons and John Wainwright and Debra C. Peters} } @conference {JRN54433, title = {Can we use the past as a lens to the future? Using historic events to predict regional grassland and shrubland responses to multi-year drought or wet periods under climate change}, booktitle = {100th Annual Meeting of the Ecological Society of America}, year = {2015}, month = {08/2015}, address = {Baltimore, MD}, abstract = {

Background/Question/Methods Ecologists are being challenged to predict ecosystem responses under changing climatic conditions. Water availability is the primary driver of ecosystem processes in temperate grasslands and shrublands, but uncertainty in the magnitude and direction of change in precipitation (increase or decrease) at site to regional scales reduces the predictive capacity to determine future trends with robust levels of acceptable risk for land managers. Long-term research networks of sites (LTER, LTAR) provide natural experiments for system responses that occurred historically during multi-year drought or wet periods (\>=4 y) that can be used to make predictions under future climate scenarios. We tested three alternative hypotheses using long-term data (12 to \> 50y) of aboveground net primary production (ANPP) from eight sites in North America where precipitation showed sequences of wet periods, multi-year drought, and no trend years. We hypothesized that ANPP in wet (or drought) periods can be best explained by: (1) long-term relationships between ANPP and precipitation, (2) relationships between ANPP and precipitation in individual wet or dry years, or (3) relationships between ANPP and precipitation in wet or dry periods. We compared regression slopes and r2 values among equations at each site to determine the relationship with the best fit. For most sites across the region, the equation developed using ANPP and precipitation during drought periods was a better predictor of ANPP during drought compared with the long-term equation. In addition, the drought period equation had a steeper slope than the long-term equation. Thus, approaches that use long-term ANPP-precipitation relationships to predict ANPP during multi-year drought will result in over-estimates of ANPP. In contrast, in wet periods at some sites, the number of wet years in a row was a better predictor of ANPP than the amount of precipitation during the wet period. Cumulative processes, including plant-soil water feedbacks, sequential plant population processes, and plant or soil legacies may be operating to influence these temporal dynamics. These equations relating ANPP to precipitation during multi-year drought or number of wet years can be used to explain historic patterns, such as the during the 1930s drought or unusual grass recovery patterns, as well as to improve future predictions under directional climate change.\  Abstract COS 5-5.

}, author = {Debra C. Peters and Jin Yao and N. Dylan Burruss and Kris Havstad and O. E. Sala and J. D. Derner and John Hendrickson and Matt A Sanderson and John M Blair and S.L. Collins} } @conference {JRN54403, title = {Climate change effects in the southwestern states of New Mexico, Arizona, Utah, Nevada, California and Hawaii}, booktitle = {National Association of Environmental Professionals Annual Conference 2015}, year = {2015}, month = {04/2015}, address = {Honolulu, HI}, abstract = {

On February 7, 2014 Thomas J. Vilsack, Secretary of the U.S. Department of Agriculture, created seven regional hubs across the U.S.\  The directors of the regional climate hubs are either from the Agricultural Research Service (ARS) or the U.S. Forest Service.\  In addition to regional hubs, there are three individual subsidiary hubs (Sub Hubs) in Davis, CA; Houghton, MI; and Rio Piedras, PR that focus on specialty crops or particularly unique working lands.\  The overall goal of the regional hubs is to maintain and strengthen agricultural production and natural resources under increasing climate variability and environmental change.\  The mission of the hubs is to develop and deliver science-based, regional specific information and technologies to agriculture and natural resource managers that enable climate-informed decision-making and provide assistance to enable land managers to implement those decisions.

}, author = {A. Rango and Caitriana Steele and Emile H. Elias and Kris Havstad} } @conference {JRN54506, title = {Connecting stakeholders and climate science: A summary of farmer, rancher, and forester climate data needs and climate change attitudes}, booktitle = {American Geophysical Union Fall Meeting}, year = {2015}, month = {12/2015}, publisher = {AGU}, organization = {AGU}, address = {San Francisco, CA}, abstract = {

The mission of the USDA Southwest Regional Climate Hub is to provide farmers, ranchers and forest land owners and managers with information and resources to cope with the impacts of climate change. As such, a clear understanding of landowner needs for weather and climate data and their attitudes about climate change is required. Here we present a summary of results from 17 peer-reviewed articles on studies pertaining to landowner needs and attitudes towards climate change adaptation and mitigation that span much of the continental U.S. and ideally represent a cross-section of different geographies. In general, approximately 75\% of landowners and farm advisors believe climate change is occurring, but disagree on the human contribution. Studies found that most farmers were supportive of adaptation responses, but fewer endorsed farm-based greenhouse gas reduction mitigation strategies. Adaptation is often driven by local concerns and requires locally specific strategies. Perceiving weather variability increased belief in human-caused climate change. Presently farmers and ranchers rely on past experience and short-range forecasts (weeks to seasons) whereas some foresters are requesting long-term predictions on the order of years to decades. Foresters indicated that most of them (74\%) are presently unable to find needed long-term information. We augment peer-reviewed literature with observations from landowner workshops conducted in Nevada and Arizona during 2014, the first year of Climate Hub operation. To better collect information about climate change needs and attitudes of farmers, ranchers and foresters across the globe, we created a Climate Change Attitudes collection in JournalMap (https://journalmap.org/usda-southwest-regional-climate-hub/climate-change-attitudes). Users anywhere can add articles to this collection, ultimately generating a comprehensive spatial resource in support of adaptation and mitigation efforts on working lands.

}, author = {A. Rango and Michael Crimmins and Emile H. Elias and Caitriana Steele and Weiss, Jeremy} } @conference {JRN54507, title = {Climate change and the water cycle: A new southwest regional climate hub curriculum unit for 6th-12th grade students}, booktitle = {American Geophysical Union Fall Meeting}, year = {2015}, month = {12/2015}, publisher = {AGU}, organization = {AGU}, address = {San Francisco, CA}, abstract = {

As climate change intensifies, increased temperatures and altered precipitation will make water, a limited resource in the arid southwestern United States, even scarcer in many locations. The USDA Southwest Regional Climate Hub (SWRCH) developed Climate Change and the Water Cycle, an engaging and scientifically rigorous education unit for 6th -12th grade students. The unit is aligned with Common Core State Standards and Next Generation Science Standards. Nine activities can be conducted over 10 instruction hours. Each activity can also stand alone.\  In partnership with SWRCH, the Asombro Institute for Science Education developed the unit. Each activity was reviewed by an educator for educational practices and by a scientist for scientific accuracy. The unit was pilot tested with 524 students in 2014, and pre- and post-tests were administered. Ninety-one percent of students were able to name a greenhouse gas on the post-test, compared to only 48\% on the pre-test. On the post-test, 86\% of students identified the relationship between average global temperature and carbon dioxide levels in the atmosphere, compared to only 52\% on the pre-test. A student commented: {\textquotedblleft}I loved all of the activities! They are fun and help us understand about what goes on in the world.{\textquotedblright} Educators who participated in pilot testing said: {\textquotedblleft}the entire curriculum is great, but I was particularly impressed with the progression of ideas and the variety of lessons,{\textquotedblright} and {\textquotedblleft}students could see the relevance and importance of these real life issues.{\textquotedblright}

}, author = {Caitriana Steele and Emile H. Elias and Stephanie Bestelmeyer and Stephanie Haan-Amato and Helena Deswood and A. Rango and Kris Havstad} } @conference {JRN54402, title = {Climate change, diversified agriculture and adaptive capacity in Hawaii}, booktitle = {13th Annual Climate Predictions Workshop, NOAA National Weather Service}, year = {2015}, month = {03/2015}, address = {Las Cruces, NM}, abstract = {

Export-oriented sugar cane and pineapple plantation agriculture once dominated Hawaii{\textquoteright}s economy but over the latter half of the 20th Century, there was a rapid decline in the production of these crops as Hawaii{\textquoteright}s competitive advantage over foreign producers dwindled. The decline of the plantations corresponds with the rise in more diversified agricultural activities which emphasize food production for local consumption. This diversification is key to maximizing the adaptive capacity of Hawaii{\textquoteright}s agriculture within a changing climate. In the context of the increasing temperatures and uncertain water availability projected for the 21st century, we present the expected exposures, sensitivity and adaptive capacity of economically and culturally important field and tree crops.

}, author = {Caitriana Steele and Emile H. Elias and A. Rango and Kris Havstad} } @article {JRN54176, title = {Calculating foraging area using global navigation satellite system (GNSS) technology}, journal = {Rangelands}, year = {2014}, month = {12/2014}, pages = {31-35}, chapter = {31}, abstract = {

Adjusting stocking rate to changing forage conditions is a critical part of pro-active range management. In general stocking rate approaches tend to assume more optimal landscape use patterns than will actually occur. Today we can monitor spatio-temporal landscape use on a 24/7 basis using animals instrumented with global navigation satellite system (GNSS) devices. Sequential 1 sec fixes taken from two cows in two different herds in 2009 and 2011 within a 433-ha arid rangeland paddock provides an example of how GNSS data categorized into stationary, foraging and walking behaviors can be used to calculate a more accurate SR.

}, keywords = {adaptive management, animal behavior, GPS, plant-animal interface, postweaning, preweaning, tracking livestock}, url = {/files/bibliography/14-032.pdf}, author = {D.M. Anderson and Richard E. Estell and Scott T. Schrader} } @article {JRN53911, title = {Constraints and time lags for recovery of a keystone species (Dipodomys spectabilis) after landscape restoration}, journal = {Landscape Ecology}, volume = {29}, year = {2014}, month = {02/2014}, pages = {665-675}, chapter = {665}, abstract = {

Habitat restoration is typically focused on reestablishing suitable conditions at a local scale, but landscape constraints may be important for keystone species with limited dispersal. We tested for time lags and examined the relative importance of local and landscape constraints on the response of the banner-tailed kangaroo rat (Dipodomys spectabilis) to restoration of Chihuahuan Desert grasslands in New Mexico, USA. Dipodomys spectabilis is a keystone species that creates habitat heterogeneity and modifies the structure of plant and animal communities. We selected 21 sites and compared density of D. spectabilis between areas treated with herbicide to control shrubs (treated areas) and paired untreated areas. We evaluated whether density of D. spectabilis depended on treatment age, local habitat quality (vegetation and soil structure), and landscape factors (treatment area and spatial connectivity). Density was greater at treated areas than at untreated areas due to a direct effect of reduced shrub cover. However, the response of D. spectabilis to restoration was lagged by a decade or more. Structural equation modeling indicated the time lag reflected a dispersal constraint as opposed to a temporal change in habitat quality. This inference was corroborated by a positive relationship between density at treated areas and connectivity to source populations. Our results indicate that density of D. spectabilis depended strongly on the spatial configuration of treated areas, which supports a landscape mosaic approach to restoration. If keystone species commonly exhibit limited dispersal ability, landscape constraints may be broadly important for shaping ecosystem structure and function after habitat restoration.

}, keywords = {colonization, connectivity, conservation, desertification, Dipodomys spectabilis, dispersal, ecosystem engineer, grassland, kangaroo rat, shrub encroachment}, doi = {10.1007/s10980-014-0003-5}, url = {/files/bibliography/14-007.pdf}, author = {Brad Cosentino and Robert L. Schooley and Brandon T Bestelmeyer and J.F. Kelly and John M. Coffman} } @article {JRN53932, title = {The changing role of shrubs in rangeland-based livestock production systems: Can shrubs increase our forage supply?}, journal = {Rangelands}, volume = {36}, year = {2014}, month = {04/2014}, pages = {25-31}, chapter = {25}, abstract = {

Projected global increases in ruminant numbers and loss of native grasslands will present a number of challenges for livestock agriculture. Escalated demand for livestock products may stimulate interest in using shrubs on western rangelands. A paradigm shift is needed to change the role of shrubs in rangeland ecosystems. Progress has occurred in identifying mechanisms to increase shrub use, but more solutions are needed to convert woody plants into red meat. Strategies for increasing shrub use could be important for rural communities to adapt to changing climate and shrub cover and for the livestock industry to adapt to predicted growth.

}, keywords = {cattle, goats, grasslands, secondary plant metabolites, sheep, woody plants}, url = {/files/bibliography/14-009.pdf}, author = {Richard E. Estell and Kris Havstad and Andr{\'e}s F. Cibils and D.M. Anderson and Scott T. Schrader} } @article {JRN54004, title = {Covariate selection with iterative principal component analysis for predicting physical soil properties}, journal = {Geoderma}, volume = {219-220}, year = {2014}, month = {05/2014}, pages = {46-57}, chapter = {46}, abstract = {

Local and regional soil data can be improved by coupling new digital soil mapping techniques with high resolution remote sensing products to quantify both spatial and absolute variation of soil properties. The objective of this research was to advance data-driven digital soil mapping techniques for the prediction of soil physical properties at high spatial resolution using auxiliary data in a semiarid ecosystem in southeastern Arizona, USA. An iterative principal component analysis (iPCA) data reduction routine of reflectance and elevation covariate layers was combined with a conditioned Latin Hypercube field sample design to effectively capture the variability of soil properties across the 6250\ ha study area. We sampled 52 field sites by genetic horizon to a 30\ cm depth and determined particle size distribution, percent coarse fragments, Munsell color, and loss on ignition. Comparison of prediction models of surface soil horizons using ordinary kriging and regression kriging indicated that ordinary kriging had greater predictive power; however, regression kriging using principal components of covariate data more effectively captured the spatial patterns of soil property{\textendash}landscape relationships. Percent silt and soil redness rating had the smallest normalized mean square error and the largest correlation between observed and predicted values, whereas soil coarse fragments were the most difficult to predict. This research demonstrates the efficacy of coupling data reduction, sample design, and geostatistical techniques for effective spatial prediction of soil physical properties in a semiarid ecosystem. The approach applied here is flexible and data-driven, allows incorporation of wide variety of numerically continuous covariates, and provides accurate quantitative prediction of individual soil properties for improved land management decisions and ecosystem and hydrologic models.

}, keywords = {data reduction, digital soil mapping, landsat, regression kriging, spatial variability, terrain analysis}, doi = {10.1016/j.geoderma.2013.12.013}, url = {/files/bibliography/14-026.pdf}, author = {Matthew Levi and Craig Rasmussen} } @article {JRN54140, title = {Consistency of wind erosion assessments across land use and land cover types: a critical analysis}, journal = {Aeolian Research}, volume = {15}, year = {2014}, month = {11/2014}, pages = {153-260}, chapter = {253}, abstract = {

In recent decades, large areas of rangeland have been converted to cropland or vice versa in the western United States and elsewhere in the world, driven largely by increased crop prices, loss of access to irrigation water, and agricultural expansion / contraction. Wind erosion and dust emissions are key processes that have not been well studied during land use and associated land cover changes. This assessment is challenging because currently no model is available that can provide field- to landscape-scale estimates of wind erosion on both rangeland and cropland, and account for soil, vegetation and management changes. In this paper, we compare aeolian sediment transport estimates from available cropland models and a number of mass flux equations developed for rangelands, for a bare soil surface with different levels of crust and surface roughness under different wind speeds. Our results show that the simulated horizontal sediment mass fluxes are similar for cropland and rangeland models at large surface crust coverage and aerodynamic roughness. In situations of small to moderate crust cover and soil roughness, horizontal mass fluxes varied by over three orders of magnitude among the tested models. A correlation analysis shows that horizontal mass fluxes simulated by cropland and rangeland models are correlated, with correlation R2 of 0.37-0.99 across different models. Finally, we propose an approach to estimate changes in aeolian transport with changes in land use. Although this approach may be limited to situations of unvegetated surfaces, it provides a preliminary method for land managers and policymakers to estimate potential wind erosion changes in response to land use change.

}, keywords = {horizontal mass flux, model comparison, RWEQ, SWEEP, WEPS, wind erosion modeling}, doi = {10.1016/j.aeolia.2014.04.007}, url = {/files/bibliography/14-038.pdf}, author = {Junran Li and Gregory S. Okin and John Tatarko and Nicholas Webb and Jeffrey E. Herrick} } @conference {JRN54422, title = {Critical thresholds and recovery of Chihuahuan Desert grasslands: Insights from long-term data}, booktitle = {98th Annual Meeting, Ecological Society of America}, year = {2013}, month = {08/2013}, publisher = {ESA}, organization = {ESA}, address = {Minneapolis, MN}, abstract = {

Background/Question/Methods:\  Desertification and other harmful state transitions in drylands are expected to accelerate with global change. Ecologists are called upon to devise methods to anticipate critical thresholds and promote recovery of desired states. As in other drylands, transitions in semiarid grasslands of the Chihuahuan Desert involve the loss of perennial grasses and their replacement by shrubs. Dryland applications of critical threshold theory suggest that as large vegetated patches become fragmented, the breakdown of soil-resource mediated feedbacks between patch size and plant survival/reproduction will accelerate vegetation loss and preclude recovery. Thus, metrics reflecting gradual changes in vegetation patch size might be used as indicators of critical thresholds and recovery trajectories. We use 100 years of observations at the Jornada Experimental Range and Jornada Basin LTER to ask: how can critical thresholds and recovery be more effectively managed?
Results/Conclusions:\  Historical data indicate that the rapid loss of the dominant perennial grass (Bouteloua eriopoda) initiated instances of state change. The shift to a persistent reduced B. eriopoda state was caused by the confluence of several factors including grazing management that emphasized forage use rather than the viability of the B. eriopoda, delayed cattle destocking at the initiation of a severe, multi-year drought period, and an episode of windy conditions that produced severe soil erosion. A 13-yr pulse-perturbation experiment sought to recreate the rapid extinction of B. eriopoda via heavy cattle grazing, but failed to do so. Even when B. eriopoda cover was reduced to very low levels, critical thresholds were not crossed and recovery rates were a linear function of existing B. eriopoda cover. Sequences of wet years promote recovery. Patch size metrics did not improve the prediction of recovery rates and were highly correlated with cover. In contrast to theoretical assumptions, measurements of B. eriopoda reproduction across a range of patch sizes indicated that the largest patches did not feature the greatest rates of plant reproductive success and suggested that a balance between competition and facilitation might govern B. eriopoda recovery. The combination of historical reconstruction and experimental results indicates that 1) B. eriopoda grasslands undergo catastrophic transitions under certain combinations of drivers, 2) transitions are not associated deterministic thresholds or proposed mechanisms reflected in theoretical models; recovery can occur with grazing rest at very low cover values, and 3) cover can be an effective indicator of vulnerability to transition. Abstract $\#$ OOS 8-5.

}, author = {Brandon T Bestelmeyer and Kris Havstad and L.N. Svejcar and Danielle Duni and Gregory S. Okin and Debra C. Peters} } @article {49841, title = {Changes in ecological stability across realistic biodiversity gradients depend on spatial scale}, journal = {Global Ecology and Biogeography}, volume = {22}, year = {2013}, pages = {19-28}, abstract = {

Aim: It is unclear how the stability of natural ecosystems and populations varies with biodiversity at spatial scales relevant to resource managers. This study evaluates whether theory and prior experiments adequately predict how stability varies with a measure of biodiversity, plant species richness, at multiple scales in naturally assembled ecosystems and assesses mechanisms through which biodiversity is proposed to affect stability.

Location: Chihuahuan desert. Historically, grasslands represented the dominant vegetation type in this landscape and shrubs were uncommon. Desertification has degraded many native grassland regions into one of several alternate states dominated by different shrub species and these regions differ in biodiversity.

Methods: Researchers at the Jornada long-term ecological research site have amassed 12 years of data on the primary productivity of individual plant species in 735 permanent 1-m2 plots distributed among 15 regions that were all historically grasslands. I used this information to describe the relationship between biodiversity and stability at the local (1 m2) and regional (3721 m2) scale and to evaluate mechanisms through which biodiversity is proposed to affect stability.

Results: At the local scale, ecosystem stability increased linearly with biodiversity while population stability tended to decline with biodiversity. At the regional scale, both ecosystem and population stability increased as a saturating function of biodiversity. Scale-dependent change in the biodiversity{\textendash}stability relationship can be explained by the spatial insurance hypothesis, asynchrony in the local productivity dynamics of the average species, and a change in species evenness with scale that weakens statistical averaging.

Main conclusions: Results from small-scale experimental studies may not directly translate to larger spatial scales but they appear to predict patterns in natural communities at small spatial scales. These results suggest that the maintenance of high biodiversity over a large spatial area is essential for maintaining ecosystem services and reducing the potential for further species extinctions.

}, keywords = {Chihuahuan Desert, ecosystem dynamics, grasslands, population dynamics, scale dependence, synchrony}, doi = {10.1111/j.1466-8238.2012.00779.x}, url = {files/bibliography/JRN00607.pdf}, author = {Chalcraft, David R.} } @article {JRN53955, title = {Crotalus Viridis (Prairie Rattlesnake)}, journal = {Herpetological Review}, volume = {44}, year = {2013}, month = {09/2013}, pages = {520-521}, chapter = {520}, abstract = {

CROTALUS VIRIDIS (Prairie Rattlesnake). DIET. Crotalus viridis feeds on small mammals (mice, ground squirrels, rats, small rabbits); it will also consume lizards, amphibians, and other snakes.\  On 3 July 2012, an adult C. viridis was photographed attempting to consume a still quivering adult male Falco sparverius (American Kestrel) at the Chihuahuan Desert Rangeland Research Center, Summerford Mountain (32.532536{\textdegree}N, 106.790825{\textdegree}W; datum WGS84), New Mexico, USA). On 06 July 2012, the site was revisited and the kestrel was found, apparently regurgitated, after being swallowed down to the top of the wings. To our knowledge, this represents the first case of attempted predation on F. sparverius by C. viridis.

}, keywords = {rattlesnake}, url = {/files/bibliography/13-036.pdf}, author = {Chepsongol, Roxanne M and Burkett, Douglas W.} } @inbook {JRN52666, title = {Cross-site comparisons of precipitation and surface water chemistry}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {46-50}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {6}, address = {Springfield, Virginia}, abstract = {

Measurements of pools and fluxes of transport or cycling of elements and compounds through the biotic and abiotic components provide critical information about the function of ecosystems. Because the time for a molecule to be completely transported through an ecosystem may be decades to millennia, long-term data provide one of the few means to estimate how ecosystems use and respond to changes in inputs of nutrients and toxic substances. This chapter tests two hypotheses related to patterns in biogeochemistry across sites: (1) patterns in atmospheric deposition over the past 20 years are different for the eastern and western parts of the U.S., and (2) changes in atmospheric deposition are related to changes in human population density for some sites. Long-term data, collected at multiple sites across the US, in chemical measurements in wet deposition, e.g., sulfur dioxide, nitrogen oxide, and ammonia emission data, and in human population size support both hypotheses.\  The results illustrate that the effects of human activities on biogeochemistry vary regionally and across the continent, and demonstrate that cross-site comparisons of long-term data can provide new insights into the spatial patterns of transport and cycling of elements and compounds.

}, 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/13-029-6.pdf}, author = {Charles T. Driscoll and Peter M. Groffman and John M Blair and Ariel E. Lugo and C. Laney and Debra C. Peters} } @inbook {JRN52664, title = {Cross-site comparisons of state-change dynamics}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {36-41}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {4}, address = {Springfield, Virginia}, abstract = {

Changes in the state of a system, for example from grasslands to shrublands or from dominance by one fish species to another species, with associated changes in other parts of the system, are often irreversible. Most of these state changes bring forth negative impacts on ecosystem, resulting in altered levels of biodiversity, rates of nutrient cycling, changes in air and water quality, and increased losses of soil and nutrients by wind and water erosion.\  This chapter illustrated six examples of state changes in various types of ecosystems: vegetation state changes in deserts, penguin dynamics in Antarctica, fish dynamics in Wisconsin lakes, plankton dynamics in the Pacific Ocean, subtidal dynamics off Pacific Coast, and shifts in coastal fish assemblages in the Pacific Ocean.\  These examples clearly show the impact of global environmental change (warming, invasive species, altered trophic structure) on the abundance and distribution of dominant and subordinate species in aquatic, marine, and terrestrial systems. Because this era of rapid environmental change is only beginning to be manifest in species responses, long-term data will continue to be needed to quantify and predict the non-linear system responses that are likely to occur in the future.

}, 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/13-029-4.pdf}, author = {Debra C. Peters and William R. Fraser and T. K. Kratz and Mark D. Ohman and Andrew Rassweiler and Sally J. Holbrook and Russell J. Schmitt} } @inbook {JRN52668, title = {Cross-site studies "by design:" Experiments and observations that provide new insights}, booktitle = {Long-Term Trends in Ecological Systems: A Basis for Understanding Responses to Global Change}, year = {2013}, pages = {72-80}, publisher = {National Technical Information Services}, organization = {National Technical Information Services}, chapter = {10}, address = {Springfield, Virginia}, abstract = {

The cross-site comparisons presented in the previous chapters are all conducted after the individual studies are completed.\  The differences in experimental design in individual studies in a posteriori cross-site studies limit the scope of questions that can be addressed, and the powerfulness and confidence in the conclusions.\  This chapter describes cross-site studies that are {\textquotedblleft}by design{\textquotedblright} where the questions, experimental layout, methods, and measurements included multiple sites from the beginning. These a priori cross-site studies provide powerful tools to understand the phenomenon of global change and to predict its impacts on ecosystems and society. Two types of a priori cross-site studies are described: (1) experimental manipulations of drivers or system properties, and (2) observations or monitoring of natural or managed ecosystems located along environmental gradients. Within each type, examples of both on-going or completed experiments and new or developing experiments are presented.\  For each example, insights that would not have been obtained with other approaches are also presented. The limitations and difficulties of this type of studies are listed.

}, 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/13-029-10.pdf}, author = {Jin Yao and O. E. Sala and Debra C. Peters} } @article {49869, title = {Characterising the spatial and temporal activities of free-ranging cows from GPS data}, journal = {The Rangeland Journal}, volume = {34}, year = {2012}, month = {06/2012}, pages = {149-161}, chapter = {149}, abstract = {

Electronic tracking provides a unique way to document animal behavior on a continuous basis.\  This manuscript describes how uncorrected 1 s GPS fixes can be used to characterize the rate of cow travel (m{\textperiodcentered}s-1) into stationary, foraging and walking activities.\  Cows instrumented with GPS devices were observed; and the beginning and ending times of the above activities were recorded.\  Data were collected across a number of days and among a number of cows in order to calculate a mean travel rate for each activity.\  GPS data were also collected when observers were absent from the paddock and these data were then characterized into the three activities based on rate of travel determined between consecutive GPS fixes.\  The activities were further characterized within a 24 h period based on the sun{\textquoteright}s angle with respect to the horizon.\  GPS data were analyzed from four cows (two in 2009 and two in 2011) and collected for four consecutive 24 h periods before weaning and seven similar time intervals following weaning.\  Weaning took place in March each year around mid-day when calves were between 223 and 234 days of age.\  These data suggest abrupt weaning caused cows to change their spatial and temporal behavior not only among but also within days.\  Overall cow travel increased (p = 0.0093) post-weaning with subtle within day behavioral changes.\  Further testing will be required to substantiate the biological implication of spatial and temporal cattle behavioral changes when developing optimum proactive husbandry practices for managing cow dominated landscapes.

}, keywords = {foraging, geospatial data, livestock, travel, weaning behaviour}, doi = {dx.doi.org/10.1071/RJ11062}, url = {/files/bibliography/12-013.pdf}, author = {D.M. Anderson and Craig Winters and Richard E. Estell and E.L. Fredrickson and Marek Doniec and Detweiler, C. and D. Rus and D. K. James and B. Nolen} } @proceedings {JRN54524, title = {Characterization of shrubland-atmosphere interactions through use of the eddy covariance method and distributed footprint sampling}, volume = {p. 36}, year = {2012}, month = {05/2012}, publisher = {Wildland Shrub Symposium Proceedings}, address = {Las Cruces, NM}, abstract = {The behavior of ecohydrological systems can be assessed from the interactions between ecosystem states and atmospheric fluxes, including water, carbon and energy dynamics. In this study, we present progress on implementing automatic and continuous measurements of soil temperature and soil moisture within the estimated footprints of eddy covariance towers at two shrubland sites in the American Southwest. The two sites are mixed shrubland in southern New Mexico at the Jornada Experimental Range and a desert savanna in southern Arizona at the Santa Rita Experimental Range. Both sites feature a high temporal variability in vegetation greenness due to rainfall seasonality induced by the North American monsoon. In addition, woody plant encroachment at each site has led to a mosaic of different herbaceous and shrub species. We expect the plant cover heterogeneity to significantly impact the eddy covariance flux measurements and that this effect cannot be adequately captured by surface measurements at the tower. Here, we present estimates of the eddy covariance footprint in each shrubland ecosystem and the sensor network design utilized for continuous measurements within each footprint. These designs relied on high--resolution elevation and vegetation classification maps derived from manned and unmanned aerial vehicles. Ultimately, this study will help characterize the ecohydrological dynamics of these shrubland systems as well as the suitability of the eddy covariance method for heterogeneous landscapes.}, author = {C.A. Anderson and Enrique Vivoni and Nicole Pierini and Ryan Templeton and A. Rango and Andrea S. Laliberte and Srikanth Saripalli} } @proceedings {JRN54526, title = {Comparing phenology of Chihuahuan desert perennial grasses and shrubs between normal and below-average precipitation years}, volume = {PS 92-59}, year = {2012}, month = {08/2012}, publisher = {Ecological Society of America}, address = {Portland, Oregon}, abstract = {Arid and semi-arid regions of the southwestern USA are especially sensitive to changes in temperature, drought frequency and intensity. Observations of plant phenology in these water-limited environments serve as salient indicators of plant responses to changing climate. Repeated consistent phenology observations in conjunction with local climatological (e.g., precipitation, temperature) and soil (e.g., moisture, temperature) measurements are key to elucidating the role of abiotic drivers in the timing of lifecycle events. Weekly observations of plant phenology were initiated in Mar 2010 at a Soil Climate Analysis Network (SCAN) site on the Jornada Experimental Range in southern New Mexico. Weekly observations for 20 individuals across three functional groups - perennial grasses (Aristida purpurea, Sporobolus spp., and Pleuraphis mutica), the deciduous shrub honey mesquite (Prosopis glandulosa) and the evergreen shrub creosote (Larrea tridentata) {\textendash} were conducted using National Phenology Network (NPN) protocols. Phenology patterns by functional group were compared and examined in the context of precipitation. We determined dates of first production of leaves (initial growth), open flowers and fruits; in addition, we calculated the time from initial growth to full canopy and from flower to fruit production for 2010 and 2011 growing seasons. Rainfall in the 2010 rain year (213.4-mm) was near the long-term average (245-mm). Aristida and Sporobolus grasses initiated growth prior to 17 Mar 2010. Mesquite initiated growth later (19 Apr 2010), but achieved full canopy within an average of 4.5 weeks. In contrast, canopy development for grasses in 2010 occurred over 22 weeks. Time from first flower to fruit for grasses in 2010 ranged from 2.0 (for Sporobolus and Pleuraphis) to 2.7 weeks (for Aristida). Rainfall in the 2011 was far below average (89.4-mm) and encapsulated 242 consecutive dry days. Initial growth for all grasses was delayed until 11 Jul 2011, presumably due to deficit rainfall conditions. In contrast, mesquite and creosote shrubs initiated growth prior to the first rain event after 08 Oct 2010 (06 Jun 2011). We hypothesize that changes in soil temperature at depth trigger initial growth for deep-rooted shrubs. No grasses produced flowers or fruit in 2011. Next steps are to evaluate the soil temperature hypothesis with soil measurements at the SCAN site and examine relationships between environmental variables and phenophase transitions using a proportional hazards model.}, author = {Dawn M. Browning and M. Mattocks} } @proceedings {JRN54533, title = {Comparison of lifespan and survival for 114 herbaceous perennials across five ecosystems in the western US}, volume = {PS 33-153}, year = {2012}, month = {08/2012}, publisher = {Ecological Society of America Abstracts}, address = {Portland, Oregon}, abstract = {Demographic characteristics such as survival and life expectancy play critical roles in population dynamics and, consequently, community structure. Though increasing attention has focused on factors underlying geographic variation in a species{\textquoteright} demographic rates, the difficulty of collecting long-term observation data for multiple species from multiple sites has limited our understanding of the influence of life form and environmental drivers. We compiled five long-term datasets from Sonoran desert, Arizona (1915-1935), Sagebrush steppe, Idaho (1923-1957), Southern mixed prairie, Kansas (1934-1972), Northern mixed prairie, Montana (1932-1945) and Chihuahuan desert, New Mexico (1915-1960), USA, to test for site-dependent demographic responses for forbs and grasses. In these datasets, all individual plants in 1-m2 permanent quadrats were annually identified and mapped, allowing us to track the lifespan of individual genets. Based on these data, we characterized the survival curves of 114 species. Pooling forb and grass species together, we found significant differences in first year survival rates across the five sites, but differences in life expectancy at year 1 and the shape of the survival curves (Type III) were not significant. For forbs, first year survival and life expectancy, but not the shape of the survival curve, differed significantly among sites. Grasses showed statistically indistinguishable patterns across all sites. In addition, we found significant differences between forbs and grasses in all three demographic rates, with forbs conforming more to Type II survivorship curves than grasses. Our results emphasize that much of the variation in survival across and within species is related to life form (forbs vs. grasses). In contrast, geographic differences in demography were relatively subtle, especially for the grasses, despite dramatic variation in climate and soils across the five sites.}, author = {Chu, Chengjin and Kris Havstad and Debra C. Peters and Peter B. Adler} } @article {49889, title = {A comparison of three feature selection methods for object-based classification of sub-decimeter resolution UltraCam-L imagery}, journal = {International Journal of Applied Earth Observation and Geoinformation}, volume = {15}, year = {2012}, month = {01/2012}, pages = {70-78}, chapter = {70}, abstract = {The availability of numerous spectral, spatial, and contextual features with object-based image analysis (OBIA) renders the selection of optimal features a time consuming and subjective process. While several feature election methods have been used in conjunction with OBIA, a robust comparison of the utility and efficiency of approaches would facilitate broader and more effective implementation. In this study, we evaluated three feature selection methods, 1) Jeffreys-Matusita distance (JM), 2) classification tree analysis (CTA), and 3) feature space optimization (FSO) for object-based vegetation classifications with sub-decimeter digital aerial imagery in arid rangelands of the southwestern U.S. We assessed strengths, weaknesses, and best uses for each method using the criteria of ease of use, ability to rank and/or reduce input features, and classification accuracies. For the five sites tested, JM resulted in the highest overall classification accuracies for three sites, while CTA yielded highest accuracies for two sites. FSO resulted in the lowest accuracies. CTA offered ease of use and ability to rank and reduce features, while JM had the advantage of assessing class separation distances. FSO allowed for determining features relatively quickly, because it operates within the OBIA software used in this analysis (eCognition). However, the feature ranking in FSO is not transparent and accuracies were relatively low. While all methods offered an objective approach for determining suitable features for classifications of sub-decimeter resolution aerial imagery, we concluded that CTA was best suited for this particular application. We explore the limitations, assumptions, and appropriate uses for this and other datasets.}, keywords = {aerial imagery, classification, feature selection, object-based image analysis, very high resolution}, doi = {10.1016/j.jag.2011.05.011}, url = {/files/bibliography/12-012.pdf}, author = {Andrea S. Laliberte and Dawn M. Browning and A. Rango} } @proceedings {JRN54538, title = {Cross-scale interactions drive ecosystem responses to precipitation in the Chihuahuan Desert}, volume = {COS 186-2}, year = {2012}, month = {08/2012}, publisher = {Ecological Society of America Proceedings}, address = {Portland, Oregon}, abstract = {Regime shifts from grass- to shrub-dominated states are widespread in arid and semiarid regions globally. These patterns of grass production and shifts to shrub dominance are spatially variable and correlate weakly with precipitation, suggesting that processes at different spatial and temporal scales interact to create spatially heterogeneous patterns of grass recruitment and growth. Focusing on a 5-year wet period at the Jornada Basin LTER site in southern New Mexico, we tested the hypothesis that a dynamic template of soil characteristics and spatial context mediate the response of grasses to periods of elevated precipitation. Data consisted of Normalized Difference Vegetation Index (NDVI) measurements from repeat satellite images before and after semiannual growing seasons, soil measurements from 75 locations across a grassland-shrubland ecotone, and monthly precipitation totals from 14 nearby rain gauges. Spatial arrangement of grasses, shrubs, and bare gaps were quantified from an object-based classification of a satellite image from immediately before the extended wet period. During this 5-year period of elevated precipitation, the greatest grass establishment and growth occurred at locations already dominated by grasses. Production also increased in some areas of mesquite (Prosopis glandulosa) dunes where fine-scale processes facilitating recruitment are normally overwhelmed by broader-scale drivers such as wind erosion. On soils with greater water-holding capacity, these fine-scale processes propagated spatially to influence patterns of recruitment and growth. On soils with lower water-holding capacity, grasses were unable to exploit an increase in precipitation and exhibited little increase in primary production. These results suggest that focusing on only fine-scale processes, such as competition, is of limited utility when cross-scale interactions govern observed patterns. A more explicit focus on multiple interacting spatial and temporal scales is often necessary to more fully understand variability in regime shifts.}, author = {Pillsbury, Finn C. and Debra C. Peters and Dawn M. Browning and Danielle Duni} } @article {49941, title = {Cross-site comparisons of precipitation and surface water chemistry}, year = {2011}, keywords = {cross-site comparisons, global change, long term trends, precipitation, surface water chemistry}, author = {Charles T. Driscoll and Peter M. Groffman and John M Blair and Ariel E. Lugo and C. Laney and Debra C. Peters} } @article {49977, title = {Cross-site comparisons of state change dynamics}, year = {2011}, keywords = {cross-site comparisons, cross-site reserarch, state change dynamics}, author = {Debra C. Peters and William R. Fraser and T. K. Kratz and Mark D. Ohman and Andrew Rassweiler and Sally J. Holbrook and Russell J. Schmitt} } @article {49982, title = {Cross-system comparisons elucidate disturbance complexities and generalities}, journal = {Ecosphere}, volume = {2}, year = {2011}, month = {07/2011}, pages = {Article 81}, chapter = {1}, abstract = {Given that ecological effects of disturbance have been extensively studied in many ecosystems, it is surprising that few quantitative syntheses across diverse ecosystems have been conducted. Multi-system studies tend to be qualitative because they focus on disturbance types that are difficult to measure in an ecologically relevant way. In addition, synthesis of existing studies across systems or disturbance types is challenging because sufficient information needed for analysis is not easily available. Theoretical advances and improved predictions can be advanced by generalizations obtained from synthesis activities that include multiple sites, ecosystems, and disturbance events. Building on existing research, we present a conceptual framework and an operational analog to integrate this rich body of knowledge and to promote quantitative comparisons of disturbance effects across different types of ecosystems and disturbances. This framework recognizes individual disturbance events that consist of three quantifiable components: (1) environmental drivers, (2) initial system properties, and (3) physical and biological mechanisms of effect, such as deposition, compaction, and combustion. These components result in biotic and abiotic legacies that can interact with subsequent drivers and successional processes to influence system response. Through time, a coarse-scale quasi-equilibrial state can be reached where variation in drivers interacting with biotic processes and feedbacks internal to the system results in variability in dynamics. At any time, a driver of sufficient magnitude can push the system beyond its realm of natural variability to initiate a new kind of event. We use long-term data from diverse terrestrial ecosystems to illustrate how our approach can facilitate cross-system comparisons, and provide new insights to the role of disturbance in ecological systems. We also provide key disturbance characteristics and measurements needed to promote future quantitative comparisons across ecosystems.}, keywords = {disburbance event, disturbance type, drought, ecological theory, global change, hurricane legacies, overgrazing, thresholds, wildfire}, doi = {10.1890/es11-00115.1}, url = {/files/bibliography/11-015.pdf}, author = {Debra C. Peters and Ariel E. Lugo and F.S. Chapin III and Steward T.A. Pickett and Danielle Duni and Rocha, Adrian V. and F. J. Swanson and C. Laney and J. W. Jones (eds.)} } @article {50000, title = {Consistent indicators and methods and a scalable sample design to meet assessment, inventory, and monitoring information needs across scales}, journal = {Rangelands}, volume = {33}, year = {2011}, month = {08/2011}, pages = {14-20}, chapter = {14}, abstract = {Within the Bureau of Land Management (BLM), as in many land management agencies throughout the world, much effort is invested in monitoring and assessment for specific management needs. The BLM Assessment, Inventory, and Monitoring (AIM) Strategy was initiated, in part, to evaluate and make recommendations to improve the efficiency and effectiveness of monitoring activities. A goal of the AIM Strategy is to provide the BLM and its partners with information needed to understand terrestrial resource location and abundance, condition, and trend, and to provide a basis for effective adaptive management.\  The Strategy supports an integrated approach that includes three components: 1) a standard set of field measurement indicators and associated methods for terrestrial vegetation and soils that reflect the status of key attributes of ecosystem sustainability ; 2) a statistically valid sampling framework that allows datasets collected in different areas and for different objectives to be aggregated at different scales to address regional and national information needs; and 3) integration of remote sensing and ground-based technologies to maximize BLM\’s capacity to cost-effectively address management questions at multiple spatial scales. Collectively, these components help ensure that data collected to support local decision-making are defensible and can be easily integrated to address multiple questions at multiple scales. The objective of this paper is to provide an overview of the three components.}, doi = {doi: 10.2111/1551-501X-33.4.14}, url = {/files/bibliography/11-024.pdf}, author = {Gordon R. Toevs and Jason W. Karl and Jason Taylor and Carol Spurrier and Michael S. Karl and Matthew Bobo and Jeffrey E. Herrick} } @proceedings {50010, title = {Characterizing foraging patterns among cattle and bonded and non- bonded small ruminants using spatial point process techniques}, year = {2010}, month = {2010}, pages = {12-35}, publisher = {Kansas State University}, address = {Manhattan, Kansas}, abstract = {

Two mixed-species livestock groups were monitored while foraging on 410 ha of brush-infested Southern New Mexico rangeland during July and August 1988. The groups consisted of crossbred Bos taurus and Bos indicus beef cattle with white-faced sheep (Ovis aries) and mohair goats (Capra hircus).\  The bonded group consisted of small ruminants that had their behaviours modified through socialization with cattle to form a flerd in which small ruminants consistently remained near cattle.\  Small ruminants in the non-bonded group had not been socialized with cattle.\  A subset of animal location data measured during the morning over five days for both the bonded and non-bonded groups was analyzed for spatial patterns.\  Only data for five morning periods (0700-0800 h) are reported because morning and afternoon spatial patterns were similar.\  Distance measures and Monte Carlo simulations for spatial point processes were used to analyze the data.\  Results suggested bonded and non-bonded groups were similar in spatial patterns of intra-specific distances for both cattle and small ruminants.\  However, bonding changed the repulsive relationship observed between cattle and non-bonded small ruminants stocked together to one of inter-specific attraction.\  Bonded small ruminants remained close to and formed inter-specific clusters with cattle.\  In addition, the mean number of bonded small ruminants near an arbitrary cow was consistently high.\  Finally, the spatial pattern of cattle across the paddock did not differ between bonded and non-bonded groups, while bonded small ruminants tended to disperse slightly more uniformly across the paddock than did non-bonded small ruminants. These findings suggest paddock utilization may be positively influenced using flerds compared to flocks and herds.

}, keywords = {animal disribution, animal locations, cattle, flerds, goats, mixed-species stocking, sheep}, url = {/files/bibliography/10-046.pdf}, author = {D.M. Anderson and Murray, Leight M. and Sun, P. and E.L. Fredrickson and Richard E. Estell and V.B. Nakamatsu} } @article {50011, title = {Changing human-ecological relationships and drivers using the Quesungual Agroforestry System in western Honduras}, journal = {Renewable Agriculture and Food System}, year = {2010}, month = {07/2008}, pages = {1-9}, chapter = {1}, abstract = {The development of sustainable agricultural production systems in the tropics is challenging in part because the local and external conditions that affect sustainability are constantly in flux. The Quesungual Agroforestry System (QSMAS) was developed in response to these changing conditions. The history and potential future of the QSMAS provide an opportunity to consider the factors that are affecting small-scale agricultural production systems on marginal lands throughout the world. In this paper we report the results of an analysis of the sustainability of the QSMAS using the five principles of the Drylands Development Paradigm (DDP) for three periods: pre-QSMAS, QSMAS adoption and the future. The analysis from the first two periods provides lessons that can be extended to other regions. The system must continue to evolve, however, if the long-term benefits of the system are to be conserved. Finally, we concluded that while the DDP was a useful framework for systematically identifying the critical drivers and processes that determine the sustainability of QSMAS, it is ultimately no more able to predict the future than the collective knowledge of those who choose to apply it. It can, however, facilitate the integration and application of this knowledge.}, keywords = {QSMAS, sustainable}, doi = {10.1017/S1742170510000074}, url = {/files/bibliography/10-018.pdf}, author = {M. Ayarza and E. Huber-Sannwald and Jeffrey E. Herrick and J. F. Reynolds and Garcia-Barrios, L. and Welchez, L.A. and Lentes, P. and Pavon, J. and Morales, J.} } @mastersthesis {50012, title = {Characterization of historical water retention structures and assessment of treatment effects in the Chihuahuan Desert}, year = {2010}, pages = {69}, school = {New Mexico State University}, type = {M.S. Thesis}, address = {Las Cruces, New Mexico}, keywords = {history, hydrology, remediation, restoration, treatment effects, water retention structures}, url = {http://libcat.nmsu.edu/vwebv/holdingsInfo?bibId=1487385}, author = {Noemi Baquera} } @conference {JRN54453, title = {Climate-soil interactions: global change, local properties, and ecological sites}, booktitle = {63rd Society for Range Management Annual Meetings}, year = {2010}, month = {02/07/2010}, publisher = {Sociiety for Range Management}, organization = {Sociiety for Range Management}, address = {Denver, CO}, abstract = {

Global climate change is predicted to alter historic patterns of precipitation and temperature in rangelands globally. Vegetation community response to altered weather patterns will be mediated at the site level by local-scale properties that govern ecological potential, including geology, topography and soils. Broad patterns in these local-scale properties are currently used in the ecological site concept as a method for classifying the landscape into relatively homogeneous units within current climatic zones. Although present vegetation distributions are often used when developing concepts for new ecological sites, the range of variation in soils, topography and geology that ultimately differentiate ecological sites often accounts for many of the local-scale properties likely important for mediating plant community responses to climate change. Barring dramatic rearrangement of landscapes, many of the combined soil-topographic-geologic properties used in ecological site delineation are not likely to change in time scales relative to management. Knowledge of processes governed by these site properties can be used to improve our understanding of climate-vegetation relationships in state-and-transition models. We review dynamic and static site properties important for mediating impacts of climate change and provide examples illustrating how understanding of site dynamics associated with these properties can add to the knowledge necessary for developing ecological site descriptions that can accommodate climate change effects. Finally, we present challenges and opportunities of using an ecological site based approach for making results of climate change studies relevant to managers concerned about climate change. Abstract $\#$ SYM-108.

}, author = {Danielle Duni and Brandon T Bestelmeyer} } @inbook {50025, title = {Calcium carbonate features}, booktitle = {Interpretation of Micromorphological Features of Soils and Regoliths}, year = {2010}, pages = {149-194}, publisher = {Elsevier B.V.}, organization = {Elsevier B.V.}, chapter = {9}, abstract = {

The precipitation of calcium carbonate is common in soils and regoliths, especially in soils of arid environments. The precipitation and the accumulation of calcium carbonate in soils and regoliths are very complex phenomena. As they are linked to the interaction between the lithosphere, the biosphere, and the atmosphere, pedogenic carbonates may be important proxies of paleoenvironmental changes. The study of the morphological expression and hierarchical organisation of calcitic pedofeatures in thin sections allows us to partially decipher the climatic, geochemical, and biological influences on the precipitation of carbonates in soils. With the contribution of submicroscopic techniques (e.g., SEM), progress has been made in the understanding of the relation between the biological activity and the precipitation of carbonate, and many calcitic features seem to be linked to biological processes, in a direct or indirect manner. The carbonates may represent a highly active phase, undergoing intense transformation such as recrystallisation, dissolution, and secondary carbonate precipitation.

}, keywords = {JRN-LTER-N0104}, isbn = {978-0-444-53156-8}, doi = {10.1016/B978-0-444-53156-8.00009-X}, author = {Durand, Nicolas and Curtis H. Monger and Canti, Matthew G.} } @article {JRN52696, title = {Coping with shrub secondary metabolites by ruminants}, journal = {Small Ruminant Research}, volume = {94}, year = {2010}, month = {10/2010}, pages = {1-9}, chapter = {1}, abstract = {

Rangelands throughout the world contain varying but often substantial proportions of shrubs. Shrubs are generally heavily chemically defended, and herbivores must either contend with their plant secondary metabolites (PSM) or avoid a significaant component of the available forage. Browsing ruminants are exposed to thousands of chemicals in infinite combinations and concentrations that are constantly changing both temporally and spatially. The success with which a herbivore navigates this complex environment is in part attributed to its ability to cope with PSM. Plant secondary metabolites can affect a number of physiological and metabolic processes (e.g., altered microbial activity, reduced digestion, compromised acid/base balance, toxicity), although negative consequences to the herbivore range from harmless to lethal, depending factors such as dose, animal species, plane of nutrition, and physiological state. Herbivores have a variety of intertwined mechanisms to cope with consumption of PSM, ranging from physiological (e.g., salivary proteins, detoxification pathways) to behavioral (e.g., avoidance, regulation of intake below critical threshold, cautious sampling, altering size and pattern of feeding bouts, diet switching, consuming diverse and/or complementary diets). Secondary compounds may affect requirements for nutrients (e.g., protein, minerals, and glucose) and water, and may alter basal metabolic rate. Energy requirements may also increase to accommodate increased travel to water and supplementation sites to counter these negative effects, particularly on arid rangelands.

}, keywords = {foraging behavior, herbivory, intake, plant secondary metabolites, ruminants, secondary chemistry, shrubs}, doi = {10.1016/j.smallrumres.2010.09.012}, url = {/files/bibliography/10-033.pdf}, author = {Richard E. Estell} } @conference {JRN54490, title = {Cumulative effects analysis (CEA) tools}, booktitle = {Society for Range Management}, year = {2010}, month = {02/2010}, publisher = {Society for Range Managment}, organization = {Society for Range Managment}, address = {Denver, CO}, abstract = {

Effective rangeland management requires careful consideration of the possible cumulative effects of different management options prior to making major management decisions. State-and-transition (S/T) models, based on ecological sites, capture our understanding ecosystem functioning and can be used to predict the potential cumulative impacts of different management regimes.\  However, management units, such as grazing allotments or ranches, contain many ecological sites.\  Thus, using S/T to assess cumulative effects at the scale of the allotment or ranch or larger has been difficult, if not impossible.\  We have developed a dynamic modeling interface, the Cumulative Effects Analysis (CEA) Tool, which allows for S/T models to be used for cumulative impact assessment across these large landscapes. We will present this tool, and demonstrate its use across two large (\>125,000 acres each) Bureau of Land Management (BLM) study areas in southern Idaho. We developed a set of S/T models based on groupings of similar ecological sites, and mapped the model states from field samples and satellite imagery. We defined a range of management scenarios related to juniper encroachment in one area and post-fire restoration in the other. Using repeated Monte Carlo simulations, we used the CEA Tool to estimate the range of potential future outcomes for each management scenario and the uncertainty in the projections. This ecological-site-based assessment allowed us to weigh the effectiveness of different scenarios in meeting management objectives.

}, author = {Jason W. Karl and Unnasch, Robert S. and Kanga, Megan and Frid, Leonardo} } @article {50047, title = {Composition of Ceanothus gregii oil as determined by steam distillation and solid-phase microextraction}, journal = {Journal of Essential Oil Research}, volume = {22}, number = {2}, year = {2010}, pages = {140-142}, abstract = {Ceanothus gregii Gray was collected from the Jornada Experimental Range in south central New Mexico. Current year{\textquoteright}s growth was collected from ten plants found within an approximate 50 m radius of the GPS coordinates N32{\textdegree}40.605{\textquoteright} and W106{\textdegree}33.486{\textquoteright}at an altitude of 1,741 m during July 2001. Composite samples of the plants were steam distilled in triplicate, and the composite oil was analyzed using both GC-FID and GC/MS. The volatile composition of the same plants was also examined using solid-phase microextraction (SPME) with a 100?m polydimethylsiloxane fiber. Mass spectra and retention indices were used to identify 41 previously described compounds. Methyl salicylate (16.8\%), hexenal (11.8\%) and n-decanal (7.0\%) were the major identified compounds.}, keywords = {Ceanothus gregii, essential oil composite, hexanal, methyl salicylate, Rhamnaceae}, url = {/files/bibliography/10-02.pdf}, author = {M.E. Lucero and Richard E. Estell and E.L. Fredrickson} } @article {50051, title = {Combined effects of impervious surface and vegetation cover on air temperature variations in a rapidly expanding desert city}, journal = {GIScience \& Remote Sensing}, volume = {47}, year = {2010}, pages = {301-320}, abstract = {

The goal of this study is to improve our understanding of the interactive function of impervious and vegetation covers at different levels of the local and intra-urban spatial scales in relation to air temperatures in an urban environment. A multiple regression model was developed using impervious and vegetation fractions at different scales to predict maximum air temperature for the entire Phoenix metropolitan area in Arizona, USA. This study demonstrates that a small amount of impervious cover in a desert city can still increase maximum air temperature despite abundant vegetation cover.

}, keywords = {air temperature, desert city, remote sensing, surface cover, vegetation cover}, doi = {10.2747/1548-1603.47.3.301 }, url = {files/bibliography/JRN00536.pdf}, author = {Myint, S. W. and Brazel, A. J. and Gregory S. Okin and Buyantuyev, A.} } @article {50052, title = {The contribution of brown vegetation to vegetation dynamics}, journal = {Ecology}, volume = {91}, year = {2010}, pages = {743-755}, chapter = {743}, abstract = {

Indices of vegetation dynamics that include both green vegetation (GV) and non-photosynthetic vegetation (NPV), that is, brown vegetation, were applied to MODIS surface reflectance data from 2000 to 2006 for the southwestern United States. These indices reveal that the cover of NPV, a measure of vegetation brownness and a component of ecosystems worldwide, is highly variable in both space and time in the study region. In the more mesic regions of the study area, the timing of peaks in NPV appears to result from simple senescence of GV at the end of the growing season. In these regions, the amplitude of GV cyclicity dominates the total vegetation signal. In contrast, in arid and semiarid regions, the amplitude of cyclicity of NPV dominates the total vegetation signal, showing the vegetation of these regions to be unexpectedly dynamic. Shrublands of southwestern United States exhibit temporal behavior in which the annual peak in NPV cover precedes the annual peak in GV cover by a few months. Several explanations for this behavior are offered. This study shows the importance of vegetation indices that include NPV, or vegetation brownness, in understanding terrestrial ecosystem dynamics, as well as the response to change for these ecosystems.

}, keywords = {deserts, grasslands, green photosynthetic, non photosynthetic, phenology remote sensing, savannas, shrublands, stress vegetation dynamics, vegetation, woodlands}, doi = {10.1890/09-0302.1}, url = {/files/bibliography/10-051.pdf}, author = {Gregory S. Okin} } @article {50054, title = {Climate change: Check the data yourself}, year = {2010}, month = {07/2010}, abstract = {Data on climatic drivers and ecological responses through time tend to be complex and difficult to use by anyone oethr than the individual scientist who collected them. We provide an alternative approach that simplifies complex datasets into derived data products including long-term trends that can be easily understood and interpreted by a broad audience. The result is a book to be published by the USDA publications office, and a website (http://www.ecotrends.info) containing the data with graphical routines that allow easy access and use of the data. Our goal is to allow users to determine for themselves if and where climate change is occurring for sites located across the continental US, Alaska, and Puerto Rico.}, url = {/files/bibliography/10-052.pdf}, author = {Debra C. Peters and William deBuys} } @conference {50058, title = {Change detection using 75-year aerial photo and satellite data sets, inexpensive means to obtain 6 cm resolution data, and developing opportunities for community-oriented remote sensing through photography}, booktitle = {2010 American Geophysical Union Fall Meeting}, year = {2010}, month = {12/2010}, address = {San Francisco, California}, abstract = {Some governmental research sites have been in existence for as many as 100 years with ground photography used for documentation starting in the early 1900s(e.g., at the USDA Jornada Experimental Range (JER) (783 km2) in south central New Mexico) If ground photography is properly documented when acquired, it can be used as a baseline for later re-photography assessments of change or for providing historical perspective. The JER historical ground photographic data base contains 3148 scenes and is available from a number of photographic archives. For long-term change detection, earth resources satellites (starting in 1972) have been valuable, but their usefulness can be enhanced when combined with data from vertical aerial photography programs begun in the mid 1930s by USDA (and other agency/aerial photo contractors). This historic aerial photography is generally an untapped data resource. Most of these aerial photos have approximately 1-2 m spatial resolution but are scattered in numerous archives around the United States. For the JER, we have been able to locate and obtain 5500 individual aerial photos which have been indispensable in evaluating vegetation change, locating treatment legacies on the landscape, and assessing rangeland treatment effectiveness. All the acquired aerial photos have been digitized and stored in the JER data base. We have also been exploring the use of small Unmanned Aerial Vehicles (UAVs) to provide hyperspatial aerial photos at about 6 cm spatial resolution to complement the 1-2 m resolution aerial photos. The areas covered by these individual UAV photos are only about 215 x 160 m, so in order to cover larger areas we have had to develop our own methods for mosaicing and analysis. In four years of flying the UAV, we have obtained about 15,000 images over JER and other western rangelands. This method is very cost effective because we are able to use an inexpensive 10 megapixel consumer-grade digital camera on the UAV as opposed to more costly aerial mapping cameras or scanners. The extreme high resolution of the images has found great application in rangeland health assessments. Archiving all these photographic products is a necessity so that future researchers can build their own studies on a firm foundation of past observations and analyses. Although we have experienced enormous advances in automated processing and classification of digital remote sensing data since the 1970s, the results are not always better that when we were working with manual interpretation of photographic products. One example is that manual techniques we used for mapping snow cover extent in the 1970-1980s in the Rio Grande basin provided data with information content that may exceed that from today{\textquoteright}s automated methods which result in less discrimination of snow cover beneath the forest canopy. Additionally, continued utilization of photography opens up the possibility of community-oriented remote sensing which can have application to developing research areas like phenology and snow hydrology where the public can contribute photos as a form of ground truth.}, author = {A. Rango and Andrea S. Laliberte and Craig Winters and Caitriana Steele and Dawn M. Browning} } @article {50062, title = {A comparison of cover pole with standard vegetation monitoring methods}, journal = {Journal of Wildlife Management}, volume = {74}, number = {3}, year = {2010}, pages = {600-604}, abstract = {

The ability of resource managers to make informed decisions regarding wildlife habitat could be improved with the use of existing datasets and the use of cost effective, standardized methods to simultaneously quantify vertical and horizontal cover. The objectives of this study were to (1) characterize vegetation structure of three semi-arid plant communities to compare a traditional wildlife method (cover pole) and standard measurements of vegetation cover, composition, height and the proportion of the soil surface covered by large intercanopy gaps that are nationally applied; (2) use this information to define the types and amounts of habitat structure information that can be derived from these standard measurements, and (3) determine the extent to which these data may substitute for cover pole data. Visual obstruction (VO), the spatial distribution of large intercanopy gaps, and vegetation cover, composition, and height were measured between June and November of 2003 on 188 transects distributed among three arid and semi-arid vegetation types in southern and central New Mexico: shrub-invaded grassland, shrubland, and savanna. Results showed that VO was strongly correlated with vegetation height for the three communities when analyzed together and for the shrubland and savanna sites when analyzed independently, but were weakly correlated at the shrub-invaded grassland site, which had a smaller range of variation. Gap intercept variables were not correlated with VO at the shrub-invaded grassland, shrubland, or savanna sites illustrating how the VO method poorly reflects the horizontal distribution of vegetation throughout the sites. We propose that a more versatile and interpretable description of wildlife habitat can be generated using a line-point intercept method together with measurements of vegetation height and the proportion of the soil surface covered by large intercanopy gaps.

}, keywords = {assessment, gap intercept, habitat quality, monitoring, visual obstruction, wildlife habitat}, doi = {10.2193/2009-136}, url = {/files/bibliography/10-012.pdf}, author = {David P. Toledo and Jeffrey E. Herrick and Laurie Abbott} } @proceedings {50087, title = {The cow-whisperer: Towards autonomous management of free-ranging cows}, year = {2009}, month = {2009}, abstract = {Animal management in the 21st century presents many challenges. Free-ranging livestock are classically controlled by herders. Today, wire fences are used in most developed countries, although they are costly to build and maintain. Furthermore, conventional fences do not foster flexible management of foraging animals. Flexibility is the key to ecological management since both plants and animals are spatially and temporally dynamic resources. Besides logging GPS data, our sensor box allows us to play arbitrary aural cues ranging from irritating sounds to gathering commands. In our first experiment, we investigate how to stimulate a cow to move her in a specific direction by playing various sounds in either the left or right ear, however, none of the audio cues evaluated proved effective. Behavioral theory suggests that a cow will avoid novel cues, in this case sounds, by moving away from them. In earlier experiments using a number of different sounds the loudness and frequency of the sounds used did not have any noticeable detrimental affect on cows. It appears that if we want to control cows without excessive stress, we need to better understand individual as well as herd behavior. In a preliminary experiment to evaluate autonomous gathering, the cows were observed to be in the corral at approximately 7:15 AM drinking water. About mid-morning the cows were returned to the middle of the pasture with an ATV. Past research using these same animals would suggest the cows would not have done what was observed next. They returned to the corral a second time the same day. Forty-five minutes after leaving the cows in the middle of the pasture where they were observed to begin foraging. The preprogrammed instruments started administering audio sounds that the cows would have associated with previous manual gathering. However, instead of immediately walking back to the corral once the audio cues began playing, the cows continued walking south. They reached the southwest corner of the pasture where they stood for approximately 20 minutes. We then returned on the ATV and turned the cows north along the west fence line. Thereafter, the cows continued to walk north along the west fence line for about a mile without further human intervention. Returning to the corral, we observed the cows as they returned to the corral this second time on March 3, 2008. The aural gathering cues were administered equally in both ears to all four cows in 30s intervals throughout their walk to the corral. These 30 s on-off intervals appear to correspond to the stop-and-go behavior one can observe in the video. This experiment suggests that preprogrammed audio cuing involving sounds associated with manual gathering may be sufficient to gather animals autonomously. However, efficient gathering requires movement in the proper direction. Therefore, we believe that directional audio cues may be required in order to establish proper animal orientation. Our next step will be to provide directional audio cues to the animals using hard- and software currently under development at MIT. In addition, we plan to investigate how many animals in a herd we would need to instrument in order to control the entire group.}, keywords = {animal, free-ranging, GPS, livestock, management}, author = {Correll, N. and Marek Doniec and R. Libeau and D. Rus and D.M. Anderson} } @article {50091, title = {Camel spider (Solifugae) use of prairie dog colonies}, journal = {Western North American Naturalist}, volume = {69}, number = {2}, year = {2009}, month = {07/2009}, pages = {272-276}, chapter = {272}, abstract = {

Solifugids (camel spiders) are widespread throughout arid regions of western North America and are thought to be important in structuring desert arthropod communities. Despite the ubiquity of camel spiders, little is known about their ecology. Black-tailed prairie dogs (Cynomys ludovicianus) are also widespread in western North America and are important ecosystem engineers, but they have been reduced in extent because of human activity. Here we report significantly greater numbers of camel spiders on black-tailed prairie dog colonies in southern New Mexico. The difference in vegetation structure created by prairie dog activity is likely the reason for the increased prevalence of camel spiders on colonies. Because camel spiders are important predators and prey, the observation that colonies support higher numbers of these animals provides a mechanism explaining differences in arthropod communities on and off colonies and explaining the preferential foraging behavior of vertebrates associated with prairie dog colonies.

}, keywords = {black-tailed prairie dogs, Chihuahuan Desert, ecosystem engineering, grassland ecology, Solifugae}, doi = {10.3398/064.069.0220}, url = {/files/bibliography/09-018.pdf}, author = {B.D. Duval and Walter G. Whitford} } @article {50097, title = {Comparison of three vegetation monitoring methods: Their relative utility for ecological assessment and monitoring}, journal = {Ecological Indicators}, volume = {9}, number = {5}, year = {2009}, month = {March 1, 2009}, pages = {1001-1008}, abstract = {

Vegetation cover and composition are two indicators commonly used to monitor terrestrial ecosystems. These indicators are currently quantified with a number of different methods. The interchangeability and relative benefits of different methods have been widely discussed in the literature, but there are few published comparisons that address multiple criteria across a broad range of grass- and shrub-dominated communities, while keeping sampling effort (time) approximately constant. This study compared the utility of three field sampling methods for ecological assessment and monitoring: line-point intercept, gridpoint intercept, and ocular estimates. The criteria used include: (1) interchangeability of data, (2) precision, (3) cost, and (4) value of each method based on its potential to generate multiple indicators. Foliar cover by species was measured for each method in five plant communities in the Chihuahuan Desert. Line- and grid-point intercept provide similar estimates of species richness which were lower than those based on ocular estimates. There were no differences in the precision of the number of species detected. Estimates of foliar cover with line- and grid-point intercept were similar and significantly higher than those based on ocular estimates. Precision of cover estimates with line-point intercept was higher than for ocular estimates. Time requirements for the three methods were similar, despite the fact that the point-based methods included cover estimates for all canopy layers and the soil surface, while the ocular estimates included only the top canopy layer. Results suggest that point-based methods provide interchangeable data with higher precision than ocular estimates. Moreover these methods can be used to generate a much greater number of indicators that are more directly applicable to a variety of monitoring objectives, including soil erosion and wildlife habitat.

}, keywords = {foliar cover, precision, rangeland vegetation, rank-order correlation, species accumulation curves, species richness}, doi = {10.1016/j.ecolind.2008.11.011}, url = {/files/bibliography/09-008.pdf}, author = {Godinez-Alvarez, H. and Jeffrey E. Herrick and M. Mattocks and David P. Toledo and Justin Van Zee} } @article {50107, title = {Can kangaroo rat graminivory contribute to the persistence of desertified shrublands?}, journal = {Journal of Arid Environments}, volume = {73}, year = {2009}, pages = {651-657}, abstract = {

Medium-sized kangaroo rats (Dipodomys spp. Gray) function as keystone species in the dynamics of desert bunchgrasses. We tested the hypothesis that kangaroo rat graminivory leads to reduced grass growth and inflorescence production, and that kangaroo rat grass consumption reflects their preferences for open microhabitats. We excluded kangaroo rats from grasses, and measured tiller loss, leaf and tiller growth and inflorescence production. We recorded the extent of tiller loss in grasses varying in tussock size or the extent of surrounding cover. Consumption of tillers by kangaroo rats was extensive, peaking in late summer. Grasses protected from kangaroo rat graminivory showed elevated leaf and tiller growth and inflorescence production. Grass tussocks protected by surrounding vegetation or large grass tussocks suffered lower graminivory than tussocks in the open or small tussocks. Our data demonstrate that the mechanism of the keystone role of kangaroo rats is through direct graminivory. We hypothesize that kangaroo rat graminivory may contribute to the persistence of desertified shrublands by limiting grass recruitment and abundance. Medium-sized kangaroo rats prefer open microhabitats and increase in abundance as such microhabitats increase, suggesting a positive feedback, with kangaroo rats increasing in abundance in overgrazed, desertified landscapes, and then contributing to their persistence through graminivory. {\textcopyright} 2009 Elsevier Ltd. All rights reserved

}, keywords = {desert bunch grasses, desertification, Dipodomys merriami, Dipodomys ordii, Eragrostis lehmanniana, graminivory, kangaroo rat, keystone species, patch use, positive feedback, small mammals, Sporobolus flexuosus}, doi = {10.1016/j.jaridenv.2009.01.001}, url = {files/bibliography/JRN00524.pdf}, author = {G. I. H. Kerley and Walter G. Whitford} } @conference {50143, title = {Changes in methodology for monitoring long-term vegetation quadrats on the Jornada Experimental Range}, booktitle = {62nd Society for Range Management Annual Meeting}, year = {2009}, month = {February 8-12, 2}, pages = {2060-16}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Alb., NM}, abstract = {Nearly 150 sq. mi. quadrats were established for long-term monitoring of vegetation dynamics on the Jornada Experimental Range in south central New Mexico in the early 1900s. Today, approximately 120 of those sites are revisited on a five year sampling rotation. Although some of the methods for data acquisition are similar to those used at the inception of this study, technological advances have allowed for a very different type of data processing and analysis today. In this poster we present ways that these methodologies have changed, and outline rationale behind use of additional or revised monitoring methods in the future. This overview includes photographs, examples of early data collection procedures, and historic documents related to the quadrat monitoring study. Analyses of these historic data have shown that landscape position, extended drought periods, and/or proximity to specific plant communities have been major factors in driving vegetation change within these quadrat plots throughout the 20th century.}, keywords = {five year, SRM}, author = {A. L. Slaughter and Connie J. Maxwell and Valerie LaPlante and Caitriana Steele} } @conference {50152, title = {Comparing beef cow behavioral syndromes to measures of productivity and spatial use of rangelands}, booktitle = {62nd Society for Range Management Annual Meeting}, year = {2009}, month = {02/2009}, pages = {2030-10}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Alb., NM}, abstract = {

Individuals within animal groups exhibit consistent behavioral patterns within or across situations known as behavioral syndromes. Proactive (nervous) vs. reactive (calm) behavioral syndromes are observed in many animal species and influence how individuals cope with stress. We investigated the relationships between stress coping styles, spatial patterns of rangeland use, and performance of 36 young cows during two consecutive calving seasons (2006-07). Feeding rate in confinement was the criterion used to classify cows into stress copying style groups. Cows were tracked using GPS collars for approximately 45 days during calving; calves were tracked with GPS collars in 2007. Compared to proactive cows (PR), reactive individuals (RE) spent more time at water (means \± SD; PR: 73 \± 50 vs. RE: 172 \± 40 min/d), used less area (PR: 21 \± 3 vs. RE: 17 \± 3 ha/d), and exhibited more concentrated movement patterns (PR: 264 \± 44 vs. RE: 313 \± 73 m traveled/ha explored). Reactive individuals had lighter body weights (PR: 434 \± 33 vs. RE: 395 \± 28 kg), longer postpartum anestrous periods (PR: 44 \± 14 vs. RE: 68 \± 18 d), and weaned lighter calves (PR: 207 \± 37 vs. RE: 179 \± 20 kg). Calves born to highly proactive cows (PR+) were lighter than those born to less proactive mothers (PR-). PR+ spent less time near their calves, traveled further from their offspring, and weaned lighter calves than PR-. Behavioral syndromes appeared to influence landscape use and beef cow productivity in this study. Cows with intermediate stress coping styles appeared to be the best suited to the biophysical characteristics of our study site.

}, keywords = {abstract, animal, behavioral, GPS, productivity, spatial use}, author = {Wesley, R.L. and Andr{\'e}s F. Cibils and Pollak, E.R. and S.H. Cox and Mulliniks, T. and M.K. Petersen and E.L. Fredrickson} } @article {50159, title = {Climate change and ecoystems of Asia with emphasis on Inner Mongolia and Mongolia}, journal = {Rangelands}, volume = {30}, number = {3}, year = {2008}, month = {06/01/2008}, pages = {46-51}, abstract = {Asia is the most populated continent with almost 3.9 billion people. More than half of these people live in rural areas, with many as pastoralists depending on livestock and rangelands for their livelihood. Rangelands occupy over 4.3 b ac (1.72 b ha) on the Asian continent, almost 38\% of the total land area. For some counties, such as Sri Lanka and Laos in southeast Asia, the percentage of rangeland within their borders is relatively minor. However, for many Asian nations rangelands are a major land category. Countries such as China, Mongolia and Russia in northern Asia, and Iran, Afghanistan and Turkey in western Asia (more commonly referred to as the Middle East) have huge expanses of grasslands and shrublands, and more than 40\% of the land in these nations is categorized as rangeland. Given these extent and diversity of rangelands across this continent, this paper will focus on an area central to the continent that is still extremely important as a pastoral landscape. The region of Mongolia and Inner Mongolia, China (boxed area within Fig. 1) represents nearly 1.3 b ac (520 m ha) of rangeland, about 30\% of the rangeland area across this continent. In both Mongolia and Inner Mongolia, livestock production on rangelands is a major source of wealth and well being. Due to large contiguous land areas of rangelands in this region, impacts to the rangeland resource from changing climate would make livestock producers especially vulnerable. In this paper, we will provide an overview of the existing status and uses of rangelands in Mongolia and Inner Mongolia, the projected impacts of climate change, and a discussion on future strategies that can be employed to adaptively manage and reduce vulnerability in this changing environment.}, keywords = {Asia, climate change, Mongolia, rangelands}, url = {/files/bibliography/08-017.pdf}, author = {Angerer, J. and G. Han and Fujisaki, I. and Kris Havstad} } @inbook {50179, title = {Carbon sequestration and sink resources in grazed lands}, booktitle = {International Rangleand Congress}, year = {2008}, note = {ProCite field[35]: Book Chapter}, month = {June 15, 2008}, pages = {240-247}, abstract = {Carbon storage in terrestrial sinks is attractive as a policy alternative in that 1) results can be achieved quickly 2) technologies for enhanced sequestration can be implemented without major economic impact and are generally associated with improved management of resources and more efficient production systems and 3) delivery infrastructure (extension, conservation programs) are in place and proven successful. However, the design and implementation of policies and programs to accelerate and realize the potential of terrestrial sequestration requires analyses that examine regional land use patterns, human activity systems and economic development objectives.}, keywords = {carbon, grazed lands, rangelands}, author = {Joel R. Brown} } @article {50174, title = {Climate change and rangelands: Responding rationally to uncertainty}, journal = {Rangelands}, volume = {30}, number = {3}, year = {2008}, month = {June 30, 2008}, pages = {3-6}, abstract = {Rangelands constitute a substantial portion of the earth{\textquoteright}s surface and contribute a wide variety of products and services to human well being. Global climate change will have an inordinate impact on rangelands because the productivity of grass and shrub dominated ecosystems is so closely linked to the short term expression of climate, weather. In general, most rangeland ecosystems and human activities associated with them are forecast to experience increasingly erratic precipitation and temperature patterns in the short and mid term future (20-100 years). Other aspects of global change, such as CO2 fertilization, invasive species and changes in land use, will also have significant effects on the ability of rangelands to meet human needs and desires.}, keywords = {climate change, rangelands}, url = {/files/bibliography/08-020.pdf}, author = {Joel R. Brown and Thorpe, J.} } @conference {50186, title = {Customizable tool for ecological data entry, assessment, monitoring, and interpretation}, booktitle = {93rd Ecological Society of America Annual Meeting}, series = {93rd ESA Annual Meetings}, year = {2008}, month = {August 4-8, 2008}, pages = {66-136}, address = {Milwaukee, WI }, abstract = {The Database for Inventory, Monitoring and Assessment (DIMA) is a highly customizable tool for data entry, assessment, monitoring, and interpretation. DIMA is a Microsoft Access database that can easily be used without Access knowledge and is available at no cost. Data can be entered for common, nationally accepted (by NRCS, BLM and others) vegetation and soil monitoring methods, including the methods described in the {\textquotedblleft}Monitoring Manual for Grassland, Shrubland, and Savanna Ecosystems.{\textquotedblright} Additionally, NRCS ecological site description data can be collected starting at a low intensity (e.g., general site characteristics, waypoints and photos) and building to a high intensity (e.g., detailed soil and vegetation data). Stored data are easily exported to other databases and spreadsheets while previously entered data can be quickly imported into the database via Excel templates. Indicators and reports, including graphs, are automatically generated from entered data. In addition to data, the database stores critical metadata such as field crew personnel, plant species lists downloaded from the USDA/NRCS PLANTS database, driving directions, method rule sets, soil data and links to photos. The objective of this poster is to make the database available to other ecologists, to review current applications, and to identify areas for future enhancements.}, keywords = {assessment, ecological, interpretation, monitoring, tool}, author = {Ericha Courtright and Jeffrey E. Herrick and Brandon T Bestelmeyer and Laura M. Burkett} } @article {50192, title = {Contributing to the mitigation of climate change using rangeland management}, journal = {Rangelands}, volume = {30}, number = {3}, year = {2008}, month = {06/2008}, pages = {7-11}, abstract = {

The mitigation of climate change through rangeland management based projects seems to be viable in the marketplace. Carbon sequestration via rangeland management has a sound basis in both economics and ecology if the offset projects are compatible with existing land uses and management systems. However, to be competitive in a global, multisectoral market, rangeland projects must operate efficiently within market prices and rules and exploit inherent competitive advantages. Rangeland carbon sequestration projects are competitive because of the relatively low cost of achieving increased soil carbon storage and compatibility with existing management operations and production systems. Documenting and verifying changes in carbon storage may be a difficult challenge. The success of rangeland projects as participants in a private sector market will be determined in large part by the ability of the rangeland management profession (scientists, advisors and managers) to develop accurate, credible and cost-effective protocols to insure that gains are real.

}, keywords = {climate change, mitigation, rangeland management}, url = {/files/bibliography/08-019.pdf}, author = {DeSteiguer, J.E. and Joel R. Brown and Thorpe, J.} } @article {50212, title = {The changing landscape: ecosystem responses to urbanization and pollution across climatic and societal gradients}, journal = {Frontiers in Ecology and the Environment}, volume = {6}, number = {5}, year = {2008}, month = {06/2008}, pages = {264-272}, chapter = {264}, abstract = {

Urbanization, an important driver of climate change and pollution, alters both biotic and abiotic ecosystem properties within, surrounding, and even at great distances from urban areas. As a result, research challenges and environmental problems must be tackled at local, regional, and global scales. Ecosystem responses to land change are complex and interacting, occurring on all spatial and temporal scales as a consequence of connectivity of resources, energy, and information among social, physical, and biological systems. We propose six hypotheses about local to continental effects of urbanization and pollution, and an operational research approach to test them. This approach focuses on analysis of \“megapolitan\” areas that have emerged across North America, but also includes diverse wildland-to-urban gradients and spatially continuous coverage of land change. Concerted and coordinated monitoring of land change and accompanying ecosystem responses, coupled with simulation models, will permit robust forecasts of how land change and human settlement patterns will alter ecosystem services and resource utilization across the North American continent. This, in turn, can be applied globally.

}, keywords = {climatic, ecosystem, gradients, journal, pollution, societal}, doi = {10.1890/070147}, url = {/files/bibliography/08-012.pdf}, author = {N.B. Grimm and Foster, D. and Peter M. Groffman and Grove, J.M. and Hopkinson, C.E. and K.J. Nadelhoffer and D.E. Pataki and Debra C. Peters} } @proceedings {50231, title = {Correlation of object-based texture measures at mutliple scales in sub-decimeter resolution aerial photography}, volume = {XXXVII4/C1}, year = {2008}, month = {August 6, 2008}, address = {Calgary}, abstract = {Texture measures are commonly used to increase the number of input bands in order to improve classification accuracy, especially for panchromatic or true color imagery. While the use of texture measures in pixel-based analysis has been well documented, this is not the case for texture measures calculated in an object-based environment. In addition, the latter application is computer intensive, and may occur at multiple segmentation scales. Therefore fewer variables are preferred and a knowledge of correlation and how it changes across segmentation scales is required. The objectives of this study were to assess correlations between texture measures as a function of segmentation scale while mapping rangeland vegetation structure groups. A 5-cm resolution true-color aerial photo mosaic was segmented at 15 consecutively coarser scales using the object-based image analysis Definiens Professional. We investigated 10 gray-level co-occurrence matrix (GLCM) texture measures, determined the optimal texture measures for each scale with a decision tree, and calculated correlation coefficients for all texture pairs. Entropy, mean and correlation were least correlated with other texture measures at all scales. The highest correlation that remained stable across all segmentation scales was found for contrast and dissimilarity. We observed both increasing and decreasing correlation coefficients for texture pairs as segmentation scale increased, and there was larger variability from one scale to the next at finer segmentations and more consistency in correlation at medium to coarse scales. This was attributed to the fact that at finer segmentation scales, smaller objects were more numerous, and the ratio of edge to interior pixels for an image object was higher than at coarser scales. At medium to coarse scales, vegetation patches were delineated more precisely, and as a result, classification accuracy and class separability were highest. Due to the sensitivity of texture to scale, an optimal segmentation scale is important in object-based analysis. This approach allowed for determining the most suitable and uncorrelated texture measures at the optimal image analysis scale, was less computer intensive than a series of test classifications, and shows promise for incorporation into rangeland monitoring protocols with very high resolution imagery.}, keywords = {imagery, object-based, panchromatic, proceedings, sub-decimeter}, url = {/files/bibliography/08-045.pdf}, author = {Andrea S. Laliberte and A. Rango} } @article {50239, title = {A cryptic microbial community persists within micropropagated Bouteloua eriopods (Torr.) Torr. cultures}, journal = {Plant Science}, volume = {174}, year = {2008}, month = {March 16, 2008}, pages = {570-575}, abstract = {

Higher plants are ubiquitously colonized with fungal endophytes, which often lack readily detectable structures. This study examines the diverse endophyte population within a single line of micropropagated Bouteloua eriopoda (Torr.) Torr., using microscopy and comparison of internal spacer (ITS) gene sequences obtained from both plant and isolated fungal tissues. Sequences amplified from three ascomycete and one basidiomycete fungi isolated from a micropropagated line were compared to seven unique, ITS sequences amplified directly from the fungal-laden micropropagated plant tissue. Clone sequences were also compared to grass ITS sequences. Bayesian analysis placed four of the seven sequences in a tight grass clade. The remaining sequences were placed in a more diverse clade representing both cultured and uncultured endophytes. Results confirm a diverse, cryptic endophyte consortium is retained within this micropropagated plant line. The probability that similar complexity is common among higher plants implies a need to revise commonly held assumptions that aseptically propagated plants are axenic. Genes and natural products derived from such systems could be microbial in origin. Meanwhile, while the development of controlled systems in which to study single plant-fungal interactions presents significant technical challenges, the potential to uncover multi-species interactions that influence plant growth and development is high.

}, keywords = {alternaria, Aspergillus ustus, endophyte, Engyodontium album, Moniliophthora, phoma}, doi = {10.1016/j.plantsci.2008.02.012}, url = {/files/bibliography/08-008.pdf}, author = {M.E. Lucero and J.R. Barrow and P. Osuna-Avila and I. Reyes-Vera} } @conference {50275, title = {A comparison of grazing behavior between desert adapted Mexican Criollo cattle and temperate British breeds using two diverse landscapes in New Mexico and Chihuahua}, booktitle = {Society for Range Management Annual Meeting}, series = {Society for Range Management }, year = {2008}, month = {January 26, 2008}, pages = {2379}, address = {Louisville, KY}, abstract = {This study was designed to test how grazing behaviors differ between desert adapted Mexican criollo cattle and temperate British beef breeds, to learn how each breed interacts with environments common to the southwestern US and northwestern Mexico. Additionally, criollo cattle may be a better breed for regional beef production systems less reliant on fossil fuels for feed supplements and other production inputs. Two sites were used: the Jornada Experimental Range (JER) in south-central New Mexico and Rancho Experimental Teseachi (RET) in central Chihuahua. The JER pasture is 2,425 ha of undulating desert grasslands receiving an average of 245 mm precipitation. Elevation of the 2,552 ha RET pasture varies from 1,900 to 2,800 m with an average annual precipitation of 580 mm. Vegetation ranges from Pinyon-Juniper-Bouteloua on the lower slopes to Pine-Oak-Muhlenbergia. Four replicates were conducted during the spring and fall at each location. In each replicate, six different mature cows per breed were were fitted with Lotek GPS collars, equipped with activity sensors, and allowed to graze each pasture with position acquired at 5-minute intervals. British cattle grazed longer per day than criollo cattle: 9.0 versus 7.3 hours at JER (P = 0.003) and 10.0 versus 9.0 hours at RET (P = 0.006) for British versus criollo cows, respectively. British cattle also traveled less each day: 8.6 versus 10.4 km /d at JER (P = 0.03) and 4.9 versus 5.6 km/d at RET (P = 0.08) for British versus criollo breeds, respectively. In addition, British breeds remained closer to water and had significantly smaller home ranges. Larger British breeds grazed more hours and used a smaller proportion of the environment than Mexican criollo cattle. Forage conditions were better than average for each location; when poorer, we hypothesize differences between breeds will be greater.}, keywords = {Chihuahua, grazing behavior, Mexican Criollo}, author = {Roacho-Estrada, J.O. and E.L. Fredrickson and G. Bezanilla and H. Raul Peinetti and Amy L. Gonzalez and Rios, J.} } @inbook {50279, title = {Changes in biodiversity and their consequences for human health}, booktitle = {Biodiversity change and human health: from ecosystem services to spread of disease}, year = {2008}, note = {//OTHER//LTER-V//entered 06/02/2008 per DEPProCite field[6]: In}, month = {2008}, publisher = {Island Press}, organization = {Island Press}, address = {Washington, DC}, keywords = {biodiversity, book, chapter, disease, ecosystem services, human health, report}, author = {O. E. Sala and Meyerson, L. A. and C. Parmesan}, editor = {O. E. Sala and Meyerson, L. A. and C. Parmesan} } @conference {50284, title = {The contribution of vegetation cover and bare soil to pixel reflectance in an arid ecosystem}, booktitle = {AGU 2008 Fall Meeting}, series = {AGU 2008 Fall Meetings}, year = {2008}, month = {December 15-19, }, address = {San Francisco, CA}, abstract = {The heterogeneity of vegetation and soils in arid and semi-arid environments complicates the analysis of medium spatial resolution remotely sensed imagery. A single pixel may contain several different types of vegetation, as well as a sizeable proportion of bare soil. We have used linear mixture modeling to explore the contribution of vegetation cover and bare soil to pixel reflectance. In October, 2006, aerial imagery (0.25 m spatial resolution) was acquired for our study sites in the Jornada Experimental Range, southern New Mexico. Imagery was also acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) for June and November, 2006. These data corresponded with pre- and post monsoon conditions. Object-based feature extraction was used to classify the aerial imagery to shrub, grass and bare ground cover classes. Percent cover was then calculated for each cover class. Visible-near-infrared and shortwave infrared ASTER reflectance data from both dates were combined into a single 18-band dataset (30 m spatial resolution). A vector overlay from the classification results of the aerial imagery was used to define pure endmember pixels in the ASTER imagery. Estimates of the proportions of shrub, grass and bare ground cover from the linear mixture modeling approach were compared with cover calculated using feature extraction from the aerial imagery. The results indicate that reflectance in ASTER pixels is likely to be a linear combination of the cover proportions of the three main cover types (shrubs, grass, bare ground). However, noticeable outliers in the relationship between cover calculated from each method, indicate there may be other variables that affect the accuracy with which can estimate cover using linear mixture modeling.}, keywords = {aerial imagery, ASTER, pixel}, author = {Caitriana Steele and Alistair Smith and A. Campanella and A. Rango} } @conference {50285, title = {Current status of the state-and-transition framework}, booktitle = {Society for Range Management Annual Meetings}, year = {2008}, month = {January 26-31, 2}, pages = {1495}, address = {Louisville, KY}, abstract = {State-and-transition models (STM) have been widely adopted as a tool for explaining plant community dynamics and response to disturbance within rangeland ecosystems. Our understanding of the STM concepts has advanced substantially since they were introduced by Westoby et al. (1989) and modified by Stringham et al. (2003). This paper summarizes recent advancements in STM concepts presented at a State-and-Transition workshop sponsored by Oregon State University and NRCS, August 2006. The STM framework is founded upon the concept of ecological resilience, however models to-date have focused primarily on ecological thresholds with little acknowledgement of the triggers and feedback mechanisms associated with a reduction in ecological resilience and a subsequent potential threshold event. Ecological resilience describes the amount of change required to transform a stable ecosystem, maintained by one set of reinforcing processes and structures, to an alternative stable state defined by a different set of processes and structures. Effective STM{\textquoteright}s must focus management attention on maintenance of ecological resilience to prevent stable states from exceeding thresholds. Resilience management changes the focus from threshold identification to within-state dynamics that influence resilience and decreases vulnerability to thresholds. Attention to within-state dynamics emphasizes the need to identify community phases that are at-risk of a threshold occurrence. Once a threshold has been crossed identification of the feedback mechanisms supporting the alternative stable state allows management to develop restoration practices specifically designed to recover the ecological processes that supported the pre-threshold state. Migration of alternative stable states back across thresholds in response to management prescriptions may be best defined as restoration pathways. Restoration pathways convey that restoration practices are required to reestablish the former state. We recommend that the STM framework incorporate triggers, at-risk communities, feedback mechanisms, and restoration pathways and develop process-specific indicators that enable managers to identify at-risk plant communities and potential restoration pathways.}, keywords = {abstract, rangeland ecosystem, state-and-transition, STM}, author = {T.K. Stringham and D.D. Briske and Brandon T Bestelmeyer and P. L. Shaver} } @article {50286, title = {Carbon fluxes on North American rangelands}, journal = {Rangeland Ecology and Management}, volume = {61}, year = {2008}, note = {//USDA//LTER V//entered 02/03/2010, pdf available}, month = {2008}, pages = {465-474}, abstract = {

Rangelands account for almost half of the earth{\textquoteright}s land surface and may play an important role in the global carbon (C) cycle. We studies net ecosystem exchange (NEE) of C on eight North American rangeland sites over a 6-yr period. Management practices sand disturbance regimes can influence NEE; for consistency, we compared ungrazed and undisturbed rangelands including four Great Plains sites from Texas to North Dakota, two Southwestern hot desert sites in New Mexico and Arizona, and two Northwestern sagebrush steppe sites in Idaho and Oregon. We used the Bowen ratio-energy balance system for continuous measurements of energy, water vapor, and carbon dioxide (CO2) fluxes at each study site during the measurement period (1996 to 2001 fore most sites). Data were processed and screened using standardized procedures, which facilitated across-location comparisons. Although almost any site could be either a sink or source for C depending on yearly weather patterns, five of the eight native rangelands typically were sinks for atmospheric CO2 during the study period. Both sagebrush steppe sites were sinks and three of four Great Plains grasslands were sinks, but the two Southwest hot desert sites were sources of C on an annual basis. Most rangelands were characterized by short periods of high C uptake (2 mo to 32 mo) and long periods of C balance or small respiratory losses of C. Weather patterns during the measurement period strongly influenced conclusions about NEE on any given rangeland site. Droughts tended to limit periods of high C uptake and thus cause even the most productive sites to become sources of C on an annual basis. Our results show that native rangelands are a potentially important terrestrial sink for atmospheric CO2, and maintaining the period of active C uptake will be critical if we are to manage rangeland for C sequestration.

}, keywords = {article, climatic variability, desert, grassland, journal, leaf area, method, Bowen ratio, NEE, net ecosystem exchange of CO2, precipitation, respiration, shrubland}, doi = {10.2111/07-108.1}, url = {files/bibliography/JRN00493.pdf}, author = {Svejcar, Tony and Angell, Raymond and James A. Bradford and W.A. Dugas and Emmerich, William and Frank, Albert B. and Gilmanov, Tagir and Haferkamp, Marshall and Douglas A. Johnson and Mayeux, Herman and Mielnick, Pat and Jack A. Morgan and Nicanor Z. Saliendra and G.E. Schuman and P. L. Sims and K. A. Snyder} } @article {50305, title = {Climate change impacts on South American rangelands}, journal = {Rangelands}, volume = {30}, number = {3}, year = {2008}, note = {//OTHER//LTER V//entered 06/02/2008 per DEP; updated 06/.26/2009 [pdf in file]}, month = {2008}, pages = {34-39}, abstract = {

South America is highly heterogeneous in terms of climate, ecosystems, human population distribution, and cultural traditions. Rangelands are located within regions with climatic conditions from arid to subhumid, and with mean annual precipitation ranges from approximately 150 to 1500 mm (6{\textendash}60 inches). The boundaries of these regions are subject to modification by local soil conditions, evaporative demands, elevation, and topography. Within South America, rangelands cover 33\% of the total land area (Fig. 1), and include grasslands, shrublands, savannas, and hot and cold deserts, but exclude hyperarid deserts.1) In terms of vegetation, rangeland ecosystems of South America have an important herbaceous component, and woody vegetation can range from scattered dwarf shrubs to an almost continuous canopy of small-stature trees. This coexistence of multiple life forms occurs because plants access soil resources differently. Trees, with deeper and more extensive root systems, are able to access deeper soil moisture and nutrients; grasses, with fine, intensive root systems, are better able to exploit resources in the upper soil layers. Fire and flooding play important roles in maintaining the balance between herbaceous and woody vegetation. Frequent flooding leads to open grasslands, whereas better drained areas support savanna species or woodland vegetation. Large grazing mammals, mainly livestock, have a pronounced effect upon the vertical/partitioned structure of savanna grasslands. The herbaceous layer in rangelands with greater rainfall is composed of both C3 and C4 species, which typically have different growth requirements; C3 species achieve maximum productivity in the cooler, early spring, whereas C4 species have maximum productivity in the warmer late spring or early summer. Rangeland in cold climates of the southern South America is populated by C3 species.

}, keywords = {article, climate change, rangeland, journal, rangeland, climate change, South America}, doi = {10.2111/1551-501X(2008)30[34:CCIOSA]2.0.CO;2}, url = {files/bibliography/JRN00495.pdf}, author = {Laura Yahdjian and O. E. Sala} } @conference {50321, title = {Complexity in rodent community respones to grassland-shrubland trasititions}, booktitle = {87th Annual Meeting American Society of Mammalogist}, year = {2007}, month = {June 6-8, 2007}, pages = {p. 89}, address = {Albuquerque, NM}, abstract = {It is believed that the abundance and diversity of Chihuahuan Desert rodents increases with shrub encroachment accompanying desertification although grassland specialist species decline with loss of perennial grasses. It has been reported, however, that a suite of biotic-abiotic interactions may influence rodent population responses to spatial variation in habitat in complex ways, mediating the general habitat/abundance relationship. The consistency of rodent responses to shrub encroachment across a landscape and over time has not been examined in the past and is the objective of this study. Between 2002 and 2006 we monitored rodent populations on five grassland-shrubland ecotone sites in the Jornada Basin (NM, USA). The ecotones are within the same vegetation types and soils (Bouteloua eriopoda and Prosopis glandulosa on coarse loamy Argids), but they are dynamic (with shrubs expanding into grasslands over the last century) and varied in total shrub and grass abundance depending on mesoclimate and disturbance history. We also monitored 23 additional grids distributed across an area of 200 square kilometers and ranging from healthy grasslands to dense mesquite dunes. Precipitation at all sites was recorded. We tested the hypothesis that rodent richness, biomass, and density/abundance were highest in shrub-dominated portions of replicate grassland-shrubland ecotones and across grassland-shrubland transitions. We found that overall rodent richness, biomass and abundance were highly variable across the landscape and responses to shrub cover and precipitation were not always linear across years. Perennial grass cover and bare ground cover did not show significant effects on rodent populations. We conclude that absolute differences in shrub cover across the landscape are more important than relative differences in vegetation structure (i.e. shrub cover) within an ecotone for aggregate measures of rodent communities.}, keywords = {abiotic, biotic, desertification, diversity, rodents}, author = {A. Campanella and Brandon T Bestelmeyer and G. Roemer and Debra C. Peters} } @conference {50322, title = {Confirmation of artificial endophyte inoculation in maize and tomato by scanning electron microscopy and PCR amplification in its sequences}, booktitle = {American Phytopathology}, series = {Proceedings American Phytopathology Meetings}, year = {2007}, month = {July 28 - August}, address = {San Diego, CA}, abstract = {Demand for drought tolerant plants is increasing because of water shortages and water quality. Many plant-microbe symbioses have been shown to increase drought resistance in multiple crops with few to no negative effects. Novel, artificially created plant-microbe crosses are being sought to increase drought. All plant species are known to support heavy loads and diverse communities of mutualistic microorganisms on their phylloplane, internal tissues and in the rhizosphere. Carbon expenditures required to support such a heavy load of organisms suggests an undue stress on the host metabolism (Johri 2006) tolerance through combining the benefits from plant breeding with the secondary metabolite production of symbiotic fungi. To initiate novel plant-microbe crosses, plant callus containing fungal endophytes or plugs from pure fungal colonies are placed directly on newly germinated seed radicals. Scanning electron microscopy (SEM) of maize inbred B73 incubated with callus from a Great Basin wild rye (Leymuscinereus) shows appresorium formation and endophyte penetration of host tissue. SEM data from tomato (Solanumlycopersicum) incubations with an endophyte isolated from Fourwing Saltbush (Atriplex canescens) show extensive fungal associations with root hairs. ITS sequence amplification (~600bp fragment) further provides evidence that a novel fungal endophyte has been transferred. Sequence analysis of ITS regions, identification of endophytes, and drought study results are pending.}, keywords = {endophyte, maize, tomato}, author = {Chambers, A. and Geary, B. and M.E. Lucero and J.R. Barrow and J. Gardner and Burr, K.} } @conference {50385, title = {Can prairie dog-cattle interactions be used to remediate desertified Chihuahuan Desert grasslands?}, booktitle = {Ecological Society of America Annual Meeting}, year = {2007}, month = {08/2007}, pages = {PS 39-205}, address = {San Jose, CA}, abstract = {

Chihuahuan Desert grasslands are undergoing a rapid transition to desert scrub conditions. In an effort to remove prairie dogs that are believed to compete with cattle, pastoralists have created a cascade of events promoting shrub expansion and severely reducing the viability of pastoralism within many Chihuahuan Desert ecosystems. The resulting desertification leads to depauperate socio-ecological conditions, with attempts to remediate desertified landscapes often being tenuous and seldom cost effective. The goal of this and other studies are to develop a better understanding of ecosystem drivers, and their interactions, within the Janos-Nuevo Casas Grandes prairie dog (Cynomys ludovicianus) complex in northwest Chihuahua. Beef cattle (Bos taurus) habitat selection was measured on a desert grassland-prairie dog ecosystem using GPS, GIS, and remote sensing technologies inside 4 x 4 km pasture. To classify vegetation we used multispectral Quickbird imagery with 60 cm resolution and eCognition software. We grouped the vegetation in 6 different types: Aristida spp. (50\%), Pleuraphis mutica (8\%), Panicum obtusum (8\%), Bouteloa gracilis (15\%), Amaranthus palmeri (4\%) and prairie dog colonies (15\%). Analyses of cattle movements during the dormant season show a direct preference for the prairie dog colonies, with minimal use of other vegetation types. In smaller scale studies beef cattle showed a preference for forages near the margins of the prairie dog colonies. From these observations we further hypothesize that cattle may help maintain black-tailed prairie dog colonies via mutualistic interactions that may promote the formation and maintenance of Chihuahuan Desert grasslands in this region.

}, keywords = {cattle, prairie dog}, author = {Sierra Corona, R. and E.L. Fredrickson and G. Ceballos and Amy L. Gonzalez and Andrea S. Laliberte and A.D. Davidson and Sanchez, R.L. and G. Bezanilla and Gevara, E.P.} } @article {50323, title = {Changes in the spatial variation of soil properties following shifting cultivation in a Mexican tropical dry forest}, journal = {Biogeochemistry}, volume = {84}, year = {2007}, pages = {99-113}, keywords = {goestatistics, Mexico, shifting cultivation, soil nutrients, spatial heterogeneity, tropical dry forest}, author = {Diekmann, Lucy O. and Lawrence, Deborah and Gregory S. Okin} } @conference {50337, title = {Conservation of resources for sustainable ecosystems: a dialogue on connecting science, policy, and management}, booktitle = {Society for Range Management, 60th Annual Meeting and Trade Show}, year = {2007}, note = {202776 duplicate. Use 209003 for reporting purposes}, month = {February 9-16, 2}, pages = {Paper No. 189}, address = {Reno/Sparks, NV}, abstract = {For over a century rangeland science has focused, with varying degrees of success, on issues of sustainable goods and services. Our goal in this paper is to analyze this research history for insights into how best to link science, policy, and management of natural resources. We describe three broad periods of rangeland science during the 20th century: 1) a Utilitarian period of the early 20th century where science was closely linked to livestock management use and grazing related policies, followed by 2) a Decoupled Period where science schizophrenically worked to serve disparate management and policy emphases of optimal yields of traditional products and identifying ecological limits and alternative ecological services, and 3) a Reconnection Period where science is slowly redefining the linkages to policy and management as fundamental ecological paradigms have changed and new management tools and policy goals are being developed. During this third period the uses and users of science have changed (both in interest and sophistication) and broadened. The three key, overriding science goals of relevance, impact, and transparency, for all fields of applied ecology have acquired new dimensions during this last Period. Given our current ecological understanding of rangelands, relevance now requires experimental approaches that span multiple spatial and temporal scales. Impact today also requires establishing improved connections to and, in some cases, direct involvement of users in the conduct of that science. Finally, continued public trust requires that all aspects of that scientific method, including data and their analyses and interpretations, need to be open and accessible. Unless we can integrate these new dimensions into our practice of rangeland science, we will not be supported by either managers or policy makers.}, keywords = {management, natural resources, policy, science, sustainable}, author = {Kris Havstad and Joel R. Brown and Debra C. Peters and Brandon T Bestelmeyer and E.L. Fredrickson and Pieper, Rex D. and Jeffrey E. Herrick} } @conference {50350, title = {Challenges in writing ecological site descriptions}, booktitle = {Society for Range Management 60th Annual Meeting and Trade Show}, year = {2007}, month = {February 9-16, 2}, pages = {Paper No. 236}, address = {Reno/Sparks, NV}, abstract = {The Natural Resources Conservation Service (NRCS) adopted the Ecological Site Description (ESD) concept in 1997. The State and Transition Model (STM) is used to describe vegetation dynamics and is an integral component of ESDs that meet users needs. NRCS is currently developing ESDs for much of the rangeland in the western U.S. Synergy Resource Solutions, Inc. worked on over 100 ESDs for southwestern Montana as a contractor to the NRCS. Development of these ESDs has raised numerous questions and issues requiring resolution and/or solutions. Challenges include: 1) consistent difinition of the relationship bewteen States versus Plant Communities versus Phases, b) the validity of the Historical Climax Plant Community concert as a state and as a reference point, c) utility of Ecological Site Information System as a valid mechanism for storing, retrieving and analyzing ESD data, d) the utility of a single plant table to represent numerous plant communities within HCPC, e) mechanisms for representing plant species which only grow in one part of the area covered by the ESD, f) generally applicable rules to determine and define transitions, and g) indicators of approaching transitions. Many local ecologists and state and national ESD specialists have provided input towards refining the ESD concept and ESD development process.}, keywords = {dynamics, Ecological Site Description, ESD, vegetaion}, author = {Kluck, J. and J. Alexander and Loretta Metz and Joel R. Brown and Meccage, R.} } @article {50355, title = {Combining Decision Trees with Hierarchical Object-Oriented Image Analysis for Mapping Arid Rangelands}, journal = {Photogrammetric Engineering and Remote Sensing}, volume = {73}, number = {2}, year = {2007}, month = {02/2007}, pages = {197-207}, abstract = {

Decision tree analysis is a statistical approach for developing a rule base used for image classification developed a unique approach using object-based rather than pixel-based image information as input for a classification for mapping arid land vegetation. A QuickBird satellite image was segmented at four different scales, resulting in hierarchical netowrk of image objects representing the image information in different spatial resolutions. This allowed differentiation of individual shrubs at a fine scale and delineation of broader vegetation classes at coarser scales. Input variables included spectral, textural and contextual image information, and the variables chosen by the decision tree included many features not available or as easily determined with pixel based image analysis. Spectral information was selected near the top of the classification trees, while contextual and textural variables were more common closer to the terminal nodes of the classification tree. The combination of multi resolution image segmentation and deceision tree analysis facilitated the selection of input variables and helped in determining the appropriate image analysis scale.

}, keywords = {hierarchical, journal, journal articles, mapping, object-oriented image}, doi = {10.14358/PERS.73.2.197 }, url = {/files/bibliography/07-002.pdf}, author = {Andrea S. Laliberte and E.L. Fredrickson and A. Rango} } @article {50358, title = {Calcium carbonate in termite galleries {\textendash} biomineralization or upward transport?}, journal = {Biogeochemistry}, volume = {82}, year = {2007}, note = {//NMSU, USDA//LTER V//entered 06/14/2007}, month = {2007}, pages = {241-250}, abstract = {

Termites and soil calcium carbonate are major factors in the global carbon cycle: termites by their role in decomposition of organic matter and methane production, and soil calcium carbonate by its storage of atmospheric carbon dioxide. In arid and semiarid soils, these two factors potentially come together by means of biomineralization of calcium carbonate by termites. In this study, we evaluated this possibility by testing two hypotheses. Hypothesis 1 states that termites biomineralize calcium carbonate internally and use it as a cementing agent for building aboveground galleries. Hypothesis 2 states that termites transport calcium carbonate particles from subsoil horizons to aboveground termite galleries where the carbonate detritus becomes part of the gallery construction. These hypotheses were tested by using (1) field documentation that determined if carbonate-containing galleries only occurred on soils containing calcic horizons, (2) 13C/12C ratios, (3) X-ray diffraction, (4) petrographic thin sections, (5) scanning electron microscopy, and (6) X-ray mapping. Four study sites were evaluated: a C4-grassland site with no calcic horizons in the underlying soil, a C4-grassland site with calcic horizons, a C3-shrubland site with no calcic horizons, and a C3-shrubland site with calcic horizons. The results revealed that carbonate is not ubiquitously present in termite galleries. It only occurs in galleries if subsoil carbonate exists within a depth of 100 cm. 13C/12C ratios of carbonate in termite galleries typically matched 13C/12C ratios of subsoil carbonate. X-ray diffraction revealed that the carbonate mineralogy is calcite in all galleries, in all soils, and in the termites themselves. Thin sections, scanning electron microscopy, and X-ray mapping revealed that carbonate exists in the termite gut along with other soil particles and plant opal. Each test argued against the biomineralization hypothesis and for the upward-transport hypothesis. We conclude, therefore, that the gallery carbonate originated from upward transport and that this CaCO3 plays a less active role in short-term carbon sequestration than it would have otherwise played if it had been biomineralized directly by the termites.

}, keywords = {arid and semiarid soils, atmospheric carbon dioxide, carbon isotopes, carbon sequestration, Chihuahuan Desert, pedogenic carbonate, termite, calcium carbonate, termite, gallery construction}, isbn = {DOI: 0.1007/s10533-006-9067-x}, doi = {10.1007/s10533-006-9067-x}, url = {files/bibliography/07-Bgchmstry-Whitford.pdf}, author = {Liu, X. and Curtis H. Monger and Walter G. Whitford} } @article {50370, title = {Cascading Events in Linked Ecological and Socio-Economic Systems}, journal = {Frontiers in Ecology and the Environment}, volume = {5}, number = {4}, year = {2007}, month = {May 2007}, pages = {221-224}, abstract = {

Cascading events that start at small spatial scales and propagate nonlinearly through time to influence larger areas often have major impacts on ecosystem goods and services. These events, such as wildfires and hurricanes, are increasing in frequency and magnitude as systems become increasingly connected through globalization processes. We need to improve our understanding of these events in order to predict their occurrence, to minimize potential impacts, and to allow for strategic recovery. In this workshop held during the ESA meeting in Merida, Mexico on 2006 January 11, we synthesized information about cascading events for systems located throughout the Americas. Our discussions included diverse examples of cascading events that share a common feature: linked ecological and human processes across scales often drive these events. In this era of globalization, we recommend studies that explicitly examine connections across scales, and the role of connectivity among non-contiguous areas as well as contiguous areas.

}, keywords = {ecological, nonlinearly, socio economic}, doi = {10.1890/1540-9295(2007)5[221:CEILEA]2.0.CO;2}, url = {/files/bibliography/07-011.pdf}, author = {Debra C. Peters and O. E. Sala and C.D. Allen and Covich, A. and M. Brunson} } @article {50368, title = {Cross-scale interactions and changing pattern-process relationships: Consequences for system dynamics}, journal = {Ecosystems}, volume = {10}, year = {2007}, month = {August 2007}, pages = {790-796}, abstract = {Cross-scale interactions occur either when fine-scale processes influence a broad spatial extent or a long time period, or when broad-scale drivers interact with fine-scale processes to determine system dynamics. Cross-scale interactions are increasing recognized as having important influences on ecosystem processes, yet, they pose formidable challenges for understanding and forecasting ecosystem dynamics. In this introduction to the special feature, \‘Cross-scale interactions and pattern-process relations\”, we provide a synthetic framework for understanding the causes and consequences of cross-scale interactions. Our framework focuses on the importance of transfer processes and spatial heterogeneity at intermediate scales in linking fine- and broad-scale patterns and processes. Transfer processes and spatial heterogeneity can either amplify or attenuate system response to broad-scale patterns and processes. Providing a framework to explain cross-scale interactions is an important step in improving our understanding and ability to predict the impacts of propagating events and to ameliorate these impacts through proactive measures.}, keywords = {ecological surprises, landscape ecology, propagating events, spatial heterogeneity, tansfer processes}, doi = {10.1007/s10021-007-9055-6}, url = {/files/bibliography/07-030.pdf}, author = {Debra C. Peters and Brandon T Bestelmeyer and M.G. Turner} } @article {JRN54971, title = {Comparison of ASTER, MASTER, and ground-based hyperspectral reflectance measurements}, journal = {Remote Sensing for Environmental Monitoring and Change Detection}, year = {2007}, pages = {237-244}, chapter = {237}, abstract = {

This study compares reflectance measured in the visible, near infra-red, and short wave infrared wavelengths by the Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER), MODIS/ASTER Airborne Simulator (MASTER), and ground-based Analytical Spectral Devices Spectro-radiometer (ASD) in a semi-arid area of the northern Chihuahuan desert in southern New Mexico, USA. This study provided a unique opportunity to compare remote sensing data collected for semi-arid rangelands from different platforms, at different scales, over different plant communities, and for different dates. ASD visible, near infrared, and shortwave infrared reflectance data (0.35 to 2.5 μm) for 12 May 2001, 6 October 2002, and 2 May 2003 were analysed and integrated to match the first 21 MASTER and first 9 ASTER bandwidths for three different vegetation communities (grass, shrub, and shrub-grass transition) and compared to MASTER and ASTER reflectance data collected for the same dates. A strong positive correlation between the measurements indicated that the three sensors were measuring similar reflectance values for the three dates and vegetation communities. Reflectance was highest from the shrub and shrub-grass transition communities and lowest from the grass community and was related to the amount of vegetation cover present. This has implications for the energy and water budgets in this region of the Chihuahuan desert where shrub communities with low ground cover are invading and replacing grass communities.

}, keywords = {ASTER, MASTER, reflectance, semi-arid grasslands, SWIR, VNIR}, url = {files/bibliography/Rango2007-01.pdf}, author = {Jerry Ritchie and T. J. Schmugge and A.F. Hsu and A. Rango} } @article {50392, title = {Cover pole design for easy transport, assembly and field use}, journal = {Journal of Wildlife Management}, volume = {72}, year = {2007}, month = {2008}, pages = {564-567}, abstract = {

Cover poles, also called Robel poles, are used to measure a variety of structural vegetation attributes commonly used in wildlife and livestock management. Although cover pole dimensions, measurement criteria, and interpretation of cover pole data vary depending on measurement objectives, the technical use of cover poles is fairly consistent. Practical use of cover poles requires that they are sturdy, lightweight, and easily transported. We describe a cover pole apparatus that can be easily constructed, transported, and assembled for use in remote locations. This self-supporting cover pole enables one person to take measurements, and can be modified for use in multiple habitats and soil types.

}, keywords = {cover pole, design, livestock, management, measure, Robel, transport, wildlife}, doi = {10.2193/2007-109}, url = {/files/bibliography/08-051.pdf}, author = {David P. Toledo and Laurie Abbott and Jeffrey E. Herrick} } @conference {50407, title = {A case study of land degradation linking biophysical and socioeconomic aspects of agroecological production systems in southern Honduras}, booktitle = {Global Environmental Change: Regional Challenges. An Earth System Science Partnership, Open Science Conference}, year = {2006}, month = {November 9, 2006}, pages = {661}, address = {Beijing, China}, abstract = {The Dahlem Desertification Protocol (DDP) was developed to analyze interrelationships within coupled human-environment systems. In this study, we apply the DDP to humid systems through an evaluation of an innovative agroecological production system in the mountains of southern Honduras, where seasonal droughts, tillage and crop residue removal have resulted in increased runoff and erosion. The agricultural land degradation found here is typical of that throughout Latin America. The Quesungual Slash and Mulch Agroforestry System (QSMAS) system is based on the management of dispersed native trees in cropped fields through pruning. Competition is minimized while crop residues are retained, promoting soil moisture and fertility conservation. Annual crops are planted on unburned fields with zero tillage. This system enables farmers to increase yields and reduce labor inputs associated with weed control. In addition, the widespread adoption of QSMAS is associated with strong participation of local communities in the development of the system and the implementation of local policies to avoid use of fire for agricultural purposes. We report the results of a recent ARIDnet workshop in which the QSMAS approach was examined in the context of the DDP. We concluded that currently application of QSMAS by more than 6,000 farmer households effectively addresses many of the socioeconomic and biophysical drivers associated with land degradation in this region. However, the analysis also indicated that further modification of the system will be required to extend it to other regions, and to address continuing changes in socioeconomic drivers.}, keywords = {agroecological, Dahlem, DDP, Honduras, land degradation, socioeconomic}, author = {M. Ayarza and Jeffrey E. Herrick and E. Huber-Sannwald and J. F. Reynolds} } @conference {50464, title = {A case study of desertification linking biophysical and socioeconomic aspects fo water use in the small Mexican village of Amapola}, booktitle = {Global Environmental Change: Regional Challenges. An Earth System Science Partnership, Open Science Conference}, year = {2006}, month = {November 9-12, 2}, pages = {660}, address = {Beijing, China}, abstract = {Desertification is a major global environmental problem of human societies in drylands and Mexico is one of the most severely affected countries in the Americas. An assessment of how hydrological, ecological, meteorological and socioeconomic processes simultaneously affect, and are affected by, land degradation is one of the most challenging issues in global change research. In June 2004, the ARIDnet network convened an interdisciplinary workshop in Mexico to apply a new conceptual framework {\textendash} the Dahlem Desertification Paradigm (DDP) {\textendash} to La Amapola, a small rural community in the Central Plateau of Mexico. The DDP focuses on the interrelationships within coupled human-environment systems that cause desertification. We provide an overview of land degradation issues in La Amapola and highlight links between the hydrological cycle and desertification by considering the interacting roles of biophysical and socioeconomic factors. We present a conceptual model emphasizing linkages between biophysical and socioeconomic factors in La Amapola in the context of hydrology and land degradation. We discuss our findings derived from the application of the major DDP assertions. Numerous cross-scale feedbacks, linkages, and causal pathways within and between the biophysical and human dimensions support the critical importance of water allocation in support of multiple and often competing ecosystem services. The livelihoods of rural communities in this region of Mexico, and the long-term sustainability of these landscapes, depend on the resolution of this issue and thus it is of central importance when evaluating desertification.}, keywords = {desertification}, author = {E. Huber-Sannwald and J. F. Reynolds and Jeffrey E. Herrick and F. Maestre} } @proceedings {50468, title = {Comparison of nearest neighbor and rule-based decision tree classification in an object-oriented environment}, volume = {CDROM}, year = {2006}, month = {July 31-August 4}, address = {Denver, CO}, abstract = {Object-oriented classification is a useful tool for analysis of high-resolution imagery due to the incorporation of spectral, textural and contextual variables. However, feature selection and incorporation of appropriate training sites can be difficult. We compared two object-oriented image classification approaches, one using a decision tree (DT), the other a nearest neighbor classification (NN) with regard to classification accuracy, effort involved and feasibility for mapping similar areas. We used a QuickBird satellite image to map arid rangeland vegetation in a 1200 ha pasture in southern New Mexico. In the DT approach, we used ground truth data from plots (8.75 m2) as input for a decision tree to create a rule base for classification. In the NN approach, larger polygons (mean=100 m2) served as training areas for a nearest neighbor classification. Overall accuracy was 80\% using the DT and 77\% using the NN classification. The DT was a superior tool for reducing the number of input features, but this technique required more field data, export to a decision tree program and was more time consuming. With the NN approach, input features were selected within the image analysis program and were applied to the classification immediately. The use of larger polygons for training and test samples was more appropriate for use in an object-oriented environment than the small plots. We concluded that for arid rangeland classification from QuickBird data, the NN technique required less time in the field and for image analysis, had comparable accuracy to the DT approach, and would be appropriate for mapping similar areas. A combination of both methods would incorporate the advantages of feature selection in a DT with the object-oriented nature of the analysis.}, keywords = {imagery, object-oriented}, url = {/files/bibliography/06-074Proc.pdf}, author = {Andrea S. Laliberte and J. Koppa and E.L. Fredrickson and A. Rango} } @conference {50484, title = {Changes in Perennial Grass Recruitment From 1858 to Present Following Woody Plant Invasion}, booktitle = {91st Ecological Society of America Annual Meeting}, year = {2006}, month = {August 6-11, 200}, pages = {99}, address = {Memphis, TN}, abstract = {Desert ecosystems of the American Southwest have experienced dramatic changes in vegetation structure and soil properties over the past several centuries with the expansion of native woody plants. This conversion from perennial grasslands to shrublands is often difficult to reverse as a result of soil degradation and low grass seed availability. Additional recruitment processes that can limit the return of grasses are seed germination and seedling establishment, processes that are affected by both soil properties and vegetation structure. Our objective was to examine and compare the probability of recruitment of the perennial grass, Bouteloua eriopoda (black grama), in 1858 and at present using the simulation model of daily soil water dynamics. We used the model to simulate recruitment probabilities of black grama for the variation in conditions found at the Jornada Basin ARS-LTER site in southern New Mexico. Vegetation and soils maps for both time periods and historical weather data were used to parameterize the model. In general, simulated recruitment probabilities were higher in 1858 when the Jornada was dominated by grasslands compared with the present, shrub-dominated system. Because recruitment of black grama is nonlinearly related to silt content of the soil and to aboveground plant cover, these changes in recruitment probabilities were dependent on location-specific changes in soil properties and vegetation cover. Our results were used to identify the locations and conditions where recruitment of black grama is still possible; these areas can then be targeted for remediation efforts. We also identified the locations where remediation efforts of this grass species will fail without significant modifications to soil properties and vegetation cover. This approach to stratifying landscapes by recruitment potential can be used for other invasive species.}, keywords = {1858, grasslands and shrublands, modeling, perennial grass, Present, recruitment, woody plant}, author = {Debra C. Peters and Curtis H. Monger and Jeffrey E. Herrick} } @article {50504, title = {Carbon dioxide emissions from exhumed petrocalcic horizons}, journal = {Soil Science Society of America Journal; Pedology, Forest Range and Wildland Soils}, volume = {70}, year = {2006}, month = {May 2006}, pages = {795-805}, abstract = {

The second largest pool of terrestrial carbon is pedogenic CaCO3. In addition to being an important sink of atmospheric CO2, pedogenic carbonate has the potential to be an important source of atmospheric CO2. The cemented form of pedogenic carbonate (the petrocalcic horizon) develops in geomorphically stable soil in arid, semiarid, and various subhumid climates. In many of these dryland areas, such as the Chihuahuan Desert of North America, erosion has stripped away overlying soil and exhumed the petrocalcic horizon, thereby lifting it into a weathering zone above the calcification zone where it normally forms. This research tested the hypothesis that Aridisols with exhumed petrocalcic horizons will emit more CO2 than neighboring noneroded Aridisols with petrocalcic horizons or neighboring Entisols. We tested this hypothesis by comparing the amount of CO2 and the delta 13C of CO2 released from the three soil types. Using a randomized complete block design, CO2 emissions were measured using NaOH and soda lime traps from June 2002 to October 2003. Neither NaOH traps nor soda lime traps detected any statistical difference in cumulative CO2 emissions from the three soil types at the P = 0.05 level. Moreover, the isotopic analysis of CO2 did not match the isotopic values of pedogenic carbonate nor were there any statistical differences (p = 0.05) in delta 13C of CO2 among the three soil types. We conclude, therefore, that exhumed petrocalcic horizons are not actively emitting CO2 at a rate significantly greater than adjacent soils; and thus, carbon stored in petrocalcic horizons can be considered a recalcitrant reservoir within the decadal timeframe pertinent to carbon sequestration policies.

}, keywords = {CO2, emissions, exhumed petrocalcic horizons, IRGA, pedogenic carbonate, soils}, url = {/files/bibliography/06-019.pdf}, author = {A. Serna-Perez and Curtis H. Monger and Jeffrey E. Herrick and L. W. Murray} } @conference {50509, title = {Characterizing soil change within the human time scale for resource assessment and prediction}, booktitle = {18th World Congress of Soil Science}, year = {2006}, month = {July 9-15, 2006}, pages = {Paper No. 16-4}, address = {Philadelphia, PA}, abstract = {Knowledge of soil conditions and the ability to predict soil response to changes in climate and management are essential for strategic resource planning and assessment at local, regional and global scales. Soil and its dynamic interactions as an ecosystem component, including anthropogenic impacts, must be characterized in order to portray causes and effects necessary to make useful predictions of future soil responses. There is sufficient expertise to achieve this goal, although it is fragmented and exists in a variety of disciplines including, among others, geomorphology, terrestrial, community and landscape ecology, ecophysiology, climatology, pedology, agronomy, range sciences, and forestry. Key processes involved in soil change are the transfer of energy and matter among communities within a landscape; feedbacks between the biotic and abiotic components; spatial and temporal patterning that reflects self-reorganization; and the threshold response within these processes that drives change in the system. The goal of this paper is to present necessary elements for integrated approaches to characterize soil change as one step toward multi-use enhancements of soil survey databases. The elements include the human time scale, attributes of soil change, disturbance impacts on ecological, pedogenic, and geomorphic processes, function-based soil resistance and resilience and non-equilibrium models. The human time scale should be defined on the basis of past human impacts on the land within the current climatic regime and likely periods of recovery, with respect to processes. Most generally stated, the human time scale covers decades to centuries. The current climate governs the geomorphic processes that are shaping or preserving the landscape today. Consequently, time zero of the human time scale should be no earlier than the beginning of the most recent episode of climatically-controlled landscape development, roughly 300-3000 years ago, even though human impacts may have occurred prior to that time. Because of the emphasis on geomorphic processes, this period differs from the Anthropocene. Predictions of soil response to management over the human time scale also require a time limit in the future. Some have proposed a management time period of decades based on common agricultural enterprise. However, the time frame of recovery must be included and it may be periods of centuries in arid and semi-arid systems where recovery of nutrients is slow and landscape aggradation and degradation processes are active. Data collection to characterize soil and its dynamic interactions within agricultural and non-agricultural ecosystems should be based on concepts that reflect change, metrics that can be measured or modeled, and conceptual models that represent biotic-abiotic interactions. Soil change is temporal variation in soil properties at a given location. Metapedogenesis provides a schematic representation of human impacts on pedogenesis and is designed to help organize research and long-term studies. Processes and concepts essential for characterizing soil change, which this author identifies as attributes of soil change, include state variables (dynamic soil properties), time changeability, reversibility, trends, rates, drivers, thresholds, and pathways of change. These attributes need to be quantified and used to calculate other function-based metrics, including resistance and resilience, which are vital parameters for sound resource management. The state and transition model as applied to rangeland ecosystems is capable of capturing non-equilibrium and non-linear dynamics of the effects of disturbances, such as management or climate change on plant-soil interactions. The state and transition model can provide a tool to organize soil-plant-disturbance information for both improved decision making at a wide variety of scales and generating research. It can also be used to illustrate and help define metrics for soil change attributes and function-based soil interpretations.}, keywords = {assessment, human, prediction, soil, time scale}, author = {A.J. Tugel and Joel R. Brown and S. Andrews and Brandon T Bestelmeyer and Jeffrey E. Herrick and K. Hipple} } @inbook {50518, title = {Climate and climatological variations in the Jornada Basin}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem. The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {44-80}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {3}, address = {New York, NY}, abstract = {The purpose of this chapter is to review the climatic data for the Jornada Basin over the period for which instrumental records exist. Over this time period, up to 83 years in the case of Jornada Experimental Range, we can deduce both the long-term mean characteristics and variability on a range of different spatial and temporal scales. Short-term variability is seen in individual rainstorms, whereas longer-term patterns are controlled spatially by factors such as large-scale circulation patterns and basin and regional orography and temporally by the large-scale fluctuations in atmospheric and oceanic circulation patterns. Variability can have significant impacts on the biogeography of a region or on its geomorphic processes, which may set in motion a series of feedbacks, most importantly those referring to desertification. Understanding the frequency and magnitude of such variability is therefore fundamental in explaining the observed landscape changes in areas such as the Jornada Basin.}, keywords = {climatic, climatological, period, variations}, url = {/files/bibliography/06-054.pdf}, author = {John Wainwright}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @article {50521, title = {A comparison of the species-time relationship across ecosystems and taxonomic groups}, journal = {Oikos}, volume = {112}, year = {2006}, note = {//NONE//LTER IV//entered 3/27/2006; updated 7/12/2006}, month = {2006}, pages = {185-195}, abstract = {

The species/time relationship (STR) describes how the species richness of acommunity increases with the time span over which the community is observed. Thispattern has numerous implications for both theory and conservation in much the sameway as the species/area relationship (SAR). However, the STR has received much lessattention and to date only a handful of papers have been published on the pattern. Herewe gather together 984 community time-series, representing 15 study areas and ninetaxonomic groups, and evaluate their STRs in order to assess the generality of the STR,its consistency across ecosystems and taxonomic groups, its functional form, and itsrelationship to local species richness. In general, STRs were surprisingly similar acrossmajor taxonomic groups and ecosystem types. STRs tended to be well fit by bothpower and logarithmic functions, and power function exponents typically rangedbetween 0.2 and 0.4. Communities with high richness tended to have lower STRexponents, suggesting that factors increasing richness may simultaneously decreaseturnover in ecological systems. Our results suggest that the STR is as fundamental anecological pattern as the SAR, and raise questions about the general processesunderlying this pattern. They also highlight the dynamic nature of most speciesassemblages, and the need to incorporate time scale in both basic and applied researchon species richness patterns.

}, keywords = {article, biodiversity, algae, biodiversity, birds, biodiversity, corals, biodiversity, fish, biodiversity, grasshoppers, biodiversity, invertebrates, biodiversity, mammals, biodiversity, plants, biodiversity, species richness, biodiversity, zooplankton, ecosystem function, biodiversity, journal, species-area relationship, SAR, species-time relationship, STR}, isbn = {0030-1299}, doi = {10.1111/j.0030-1299.2006.14223.x}, url = {files/bibliography/JRN00435.pdf}, author = {White, Ethan P. and Peter B. Adler and W. K. Lauenroth and Gill, Richard A. and Greenberg, David and Dawn M. Kaufman and Andrew Rassweiler and Rusak, James A. and M. D. Smith and Steinbeck, John R. and R. B. Waide and Jin Yao} } @inbook {50522, title = {Chihuahuan Desert Fauna: Effects on Ecosystem Properties and Processes}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {247-265}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {12}, address = {New York, NY}, abstract = {This chapter addresses the direct and indirect effects of animals on ecosystem processes and/or their effects on ecosystem properties. This has been the primary focus of animal studies on the Jornada Experimental Range (JER) and the Chihuahuan Desert Rangeland Research Center (CDRRC) during the twentieth century. Early studies dealt with animal species that were thought to reduce the amount of primary production that was available to support livestock. With the establishment of the International Biological Programme (IBP) in the late 1960s and its premise that ecosystems could be modeled based on the energy flow conceptual model, animal studies were designed to measure energy flow through consumer populations. Those studies yielded estimates of consumption of live plant biomass between 1 and 10\% of the annual net primary production. It was concluded that, in most ecosystems, consumers process only a small fraction of the net primary production as live plant material and consumers play important roles in ecosystems as regulators of ecosystem processes and a less important role in energy flow. This hypothesis has been the focus of animal studies in the Jornada Basin for nearly 30 years. Studies of animals as regulators of ecosystem processes led to the expansion of this hypothesis to include the effects of animals on ecosystem properties. Expanding the spatial scale of studies from the patch to the watershed and landscape engendered hypotheses that animals have an effect on processes at those scales because of animal activities that affect redistribution of soil and organic matter.}, keywords = {Chihuahuan Desert, Jornada Basin, LTER, synthesis book}, url = {/files/bibliography/06-063.pdf}, author = {Walter G. Whitford and Brandon T Bestelmeyer}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @article {50537, title = {Community response to removals of plant functional groups and species from a Chihuahuan Desert shrubland}, journal = {Oikos}, volume = {110}, number = {1}, year = {2005}, note = {//NMSU//LTER IV// Email notification Jan 3, 2005 by Huenneke that paper is in press; updated 8/13/2008 (corrected author spelling)}, month = {2005}, pages = {67-80}, abstract = {

Arid and semi-arid ecosystems often exhibit diverse plant growth forms in water-limited environments, but it is unclear whether resource competition (interference) is actually important in structuring communities. We chose a diverse Chihuahuan desert shrubland to examine the response of the plant community to experimental removals of selected perennial plant species or groups of species. Four treatments involved the removal of all individuals of all species of a single functional group (functional group removals: shrub removal, succulent removal, subshrub removal, perennial grass removal). Three other treatments involved removing species within functional groups. These seven treatments plus a control (no plants removed) were replicated six times each in 25x25 m experimental plots, in summer 1995. Permanent belt transects were surveyed for number and sizes of all vascular plants in spring and fall in 1997, 1999, 2000, and 2001. Those plots from which the dominant shrub, Larrea tridentata, was removed had not recovered in total plant cover or volume by 2001, but cover and volume in all other treatments were similar to those in control plots. Relatively few species demonstrated a positive response to the removal of other species or functional groups. The perennial grass group and forbs were the most responsive; perennial grass cover increased in the shrub removal treatment relative to the control but treatment differences diminished after dry growing seasons in 2000 and 2001. Results over the first five years suggest that either environmental conditions or intrinsic biological characteristics limit the ability of most plant species to respond to the removal of substantial fractions of community biomass and composition in the short term. Such slow response by both dominant and less abundant components of the community has implications for the recovery of semi-arid systems after human disturbance or other events leading to the reduction of biological diversity.

}, keywords = {article, articles, biodiversity, removal experiments, journal, journals, plant community response, functional groups, plant community, competition, plant community, ecosystem dynamics, plant, biodiversity, plant, ecosystem dynamics, shrubland, plant functional groups}, doi = {10.1111/j.0030-1299.2005.13949.x}, url = {files/bibliography/JRN00425.pdf}, author = {M. Buonopane and Huenneke Laura Foster and M.D. Remmenga} } @conference {50549, title = {Collaborative animal science research: impacts of agriculture and trade policies on cross-border rangeland research and management}, booktitle = {Society for Range Management, 58th Annual Meeting and Trade Show}, year = {2005}, month = {February 5, 2005}, pages = {Paper No. 115}, address = {Fort Worth, TX}, abstract = {In sharing a common boundary, Mexico and the United States also shares common landscapes and an agricultural economy that is inextricably linked. Due to the high degree of connectedness between these countries, factors that affect one country also affect the other, either directly or indirectly. Current problems in the border region include extended drought, land degradation, and depletion of essential resources such as water. These problems are exacerbated by ensconced political and social systems resistant to change. The implications of these events are profound, and often referred to as being near catastrophic. Collaborative research between Mexican and US researchers offers numerous benefits by combining human and material resources to solve common problems. Despite these benefits, language, social customs, and political policies can create barriers to collaborative efforts that reduce the effectiveness and the overall number of collaborative efforts. When anticipated and appropriately planned for, these barriers can effectively be dealt with. We discuss these potential barriers and how to address them by relating our experiences with collaborative Mexican-US projects on the conservation and use of northern Mexican criollo beef cattle breeds in semiarid and arid environments.}, keywords = {agriculture and trade policies, animal science research, cross-border, management, rangeland, research}, author = {E.L. Fredrickson and G. Bezanilla} } @conference {50552, title = {Criollo Cattle: An Examination of the Past with an Eye to the Future}, booktitle = {American Society of Animal Science, New Mexico Branch American Association of Laboratory Animal Scientists}, year = {2005}, month = {August 5, 2005}, address = {New Mexico State University, Las Cruces, NM}, abstract = {During his second voyage in 1492, Columbus introduced the first cattle to the New World. Since their introduction from Andalusia, these cattle have undergone 500 year sof co-evolution with the lanscapes of North and South America. Focusing on arid regions of Chihuahua, Sonora, and Baja California, we are undertaking a series of studies to better understand the arid land adaptations of "criollo" cattle and their potential effects on vegetation change. While the oldest breed in the United States, these cattle may again prove useful in shaping the future of the North American beef cattle industry.}, keywords = {1492, Andalusia, cattle, Columbus}, author = {E.L. Fredrickson and Richard E. Estell} } @conference {50554, title = {Challenges and advances toward sustained utilization of arid USA systems}, booktitle = {The Summaries for International Symposium: Sustainable Utilization of Indigenous Plant and Animal Genetic Resources in the Mediterranean Region}, year = {2005}, month = {October 14-16, 2}, pages = {6}, address = {Bosnia and Herzegovina}, abstract = {Sustainable use of renewable resources in arid USA systems requires large amounts of land because productivity is generally very low. As a result, there are a great variety of soil types, vegetation, and land tenure within any land use enterprise. The sensitivity of soils and vegetation to overuse and their ability to recover when use levels are reduced varies among different types of soil and vegetation. In addition, land use goals and legal restrictions differ among the private, state, federal, and tribal tenure types. This spatial variation presents significant challenges to the planning, implementation and monitoring efforts needed to achieve sustainable use of these resources. General principles and conceptual models are now being developed and employed to address these challenges and to highlight areas that require additional research. These principles and models need to be applied at site and landscape spatial scales and should be based on realistic characterizations and predictions. One important principle is the need to incorporate local indigenous knowledge into these characterizations for effective management. On-the-ground application of these models will maximize chances of sustainable use through closer and more effective interactions among scientists, stewards, and producers.}, keywords = {indigenous, mediterranean, renewable, sustainable, vegetation}, author = {Kris Havstad and M.P. McClaran} } @booklet {50562, title = {Comments on {\textquotedblleft}Simultaneous Measurement of Soil Penetration Resistance and Water Content with a Combined Penetrometer{\textendash}TDR Moisture Probe{\textquotedblright} and {\textquotedblleft}A Dynamic Cone Penetrometer for Measuring Soil Penetration Resistance{\textquotedblright}}, howpublished = {Soil Science Society of American Journal}, volume = {69}, year = {2005}, note = {Response to PDF 05-015 (ARIS $\#$ 167841) Comments and Letters to the Editor}, month = {May 6, 2005}, pages = {925-927}, type = {Comments and Letters to the Editor}, abstract = {Concurrence that by accounting for momentum, the Eq. [8] may more accurately reflect the energy transmitted from the sliding hammer to the penetrometer described in Herrick and Jones (2002).\  We also agree that their new estimate of the resistance (Eq.[9]) remains \"an experiemental measurement wich does not give a unique soil property; rather it is a complex measure which depend on both the penetrometer and the soil condition (Minasny and McBratnew, 2005).\  http://soil.scijournals.org/cgi/reprint/69/3/925?maxtoshow=\&HITS=10\&hits=10\&RESULTFORMAT=\&andorexacttitle=and\&andorexacttitleabs=and\&andorexactfulltext=and\&searchid=1\&FIRSTINDEX=0\&sortspec=relevance\&volume=69\&firstpage=925\&resourcetype=HWCIT}, keywords = {moisture probe, penetration, penetrometer}, url = {/files/bibliography/05-016.pdf}, author = {Jeffrey E. Herrick} } @conference {50560, title = {Conceptual model of desertification}, booktitle = {51st Annual Meeting of the Central American Cooperative Program for Crop and Livestock Improvement (PCCMCA)}, year = {2005}, month = {2005}, abstract = {Las causes de la degradaci{\'o}n del suelo son tan diversas y complejas como sus efectos. Los proyectos de desarrollo que dirigirse solamente a las causas y los efectos biof{\'\i}sicos frecuentemente fallan porque no se ha considerado las condiciones socioecon{\'o}micas. Tambi{\'e}n, las intervenciones socioecon{\'o}micos son limitadas por los las condiciones y los procesos biof{\'\i}sicos. Adem{\'a}s, la escala de las intervenciones biof{\'\i}sicas y socioecon{\'o}micas muchas veces no coincide con la escala de las causas de degradaci{\'o}n. La probabilidad de un fracaso sube cuando cient{\'\i}ficos fuera de una regi{\'o}n (como norteamericanos trabajando en Am{\'e}rica Latina) intenta contribuir al combate de la degradaci{\'o}n sin entender ni el contexto biof{\'\i}sico ni socioecon{\'o}mico. Para empezar enfrentar ese problema, un grupo internacional desarrollo un marco conceptual de desertificaci{\'o}n, el paradigma de la desertificaci{\'o}n de Dahlem. Este paradigma se basa en considerar de manera simult{\'a}nea las dimensiones meteorol{\'o}gicas, ecol{\'o}gicas y humanas (los factores biof{\'\i}sicos y socioecon{\'o}micos) de la desertificaci{\'o}n (DDP) a varias escalas. El DDP se basa en una serie de fuentes e incluye aspectos de los procesos no lineares, la resiliencia, la vulnerabilidad, la ecolog{\'\i}a de los agroecosistemas, las percepciones humanas, la teor{\'\i}a jer{\'a}rquica y el an{\'a}lisis econ{\'o}mico. Como ocurre con la mayor{\'\i}a de los paradigmas, las ideas que constituyen el DDP no son nuevas. La manera de combinarlas supone una nueva visi{\'o}n de un {\textquotedblleft}viejo{\textquotedblright} problema que permite a su vez profundizar en su conocimiento y perfilar las acciones que ser{\'a}n necesarias llevar a cabo en el futuro para ello. El DDP se compone de 9 afirmaciones principales. La presentaci{\'o}n incluyera un an{\'a}lisis preliminaria de la relevancia de cada uno de esas afirmaciones a los problemas de degradaci{\'o}n del suelo en Centro Am{\'e}rica a varias escalas.}, author = {Jeffrey E. Herrick} } @proceedings {50572, title = {Classification of arid rangelands using an object-oriented and multiscale approach with QuickBird imagery}, year = {2005}, month = {March 7, 2005}, address = {Baltimore, Maryland}, abstract = {The classification of arid rangelands often presents unique problems due to the high reflectance of the soil background, a mixture of green and senescent grasses, and the prevalence of shrubs in grasslands, which can make it difficult to determine the proportion of grass cover from high resolution imagery. On the Jornada Experimental Range (JER), operated by the USDA Agricultural Research Service, ongoing research is aimed at determining the relationship between ground-based observations and remotely sensed data. Specific objectives of this study were to use near-earth photography and QuickBird satellite imagery to develop a detailed vegetation classification of a 1200 ha pasture in order to ascertain the extent of grassland and identify locations, extent and percent cover values for several grass species. We conducted extensive field sampling by taking photos of the ground vegetation from a height of 2.8 m and used thresholding techniques to determine percent vegetation cover and percent bare soil. The QuickBird image was analyzed with an object-oriented approach using the software eCognition. The segmentation was performed at 2 different scales, which was used to construct a hierarchical network of image objects representing the image information in different spatial resolutions simultaneously. This allowed for differentiation of individual shrubs on the lower level, and delineation of broader landscape classes on a higher level. For each image object containing the field plot, several spectral, spatial, and texture characteristics were extracted from the image. Ancillary information included soils, elevation, aspect and slope layers. The data was analyzed using classification and regression trees to determine correlations between features of the segmented image objects and the measured field plot parameters. The object-oriented classification of the QuickBird image worked favorably in this study, because shrubs could be classified separately at a finer scale, while the shrub-interspace vegetation could be analyzed at a coarser scale. This allowed us to get a reliable estimate of grass cover and shrub density in the pasture as well as shrub density within different grass species. The rule base derived from the decision tree proved to be successful at differentiating between the dominant grass species as well as defining several classes of percent grass cover. This approach shows promise for identifying detailed vegetation characteristics on arid rangelands. Future research will include refining the predictive ability of the decision tree and determining the possibility of applying this model to other locations and/or to other scales.}, keywords = {approach, arid rangelands, multiscale, object-oriented, QuickBird imagery}, url = {/files/bibliography/05-037ABS.pdf}, author = {Andrea S. Laliberte and A. Rango and E.L. Fredrickson} } @article {50575, title = {The composition of Dalea formosa oil determined by steam distillation and solid-phase microextraction}, journal = {Journal of Essential Oil Research}, volume = {17}, year = {2005}, month = {November 2005}, pages = {645-647}, abstract = {

Dalea formosa Torr. (feather dalea, featherplume) was collected from the Jornada Experimental Range in south central New Mexico. Current year{\textquoteright}s growth was collected from 10 plants, all found within an approximate 50 m radius of the GPS coordinates N32o40.645{\textquoteright} and W106o33.601{\textquoteright} during July 2001. Composite samples of the plants were steam-distilled in triplicate, and the essential oil was analyzed using both GC-FID and GC/MS. To explore the possibility of using solid-phase microextraction (SPME) in place of steam distillation, compositions of plants collected from the same site were also examined using SPME. Mass spectra and retention indices were used to identify 58 previously described compounds. The retention index and EI mass spectra are provided for one unknown. Alpha-pinene (31.7\%), camphene (8.4\%), and limonene (8.1\%) were the major constituents of the oil. Beta-pinene made up only 5.8\% of the oil but accounted for 13.2\% of the SPME chromatogram peak area. This difference in composition may be du to either sampling technique or harvesting time.

}, keywords = {composition, Dalea formosa, solid-phase microextraction, SPME, steam distillation}, doi = {10.1080/10412905.2005.9699022}, url = {/files/bibliography/05-014.pdf}, author = {M.E. Lucero and Richard E. Estell and Ruth L. Sedillo} } @article {50578, title = {Composition and antimicrobial activity of Anemposis californica leaf oil}, journal = {Journal of Agricultural and Food Chemistry}, volume = {53}, year = {2005}, month = {October 7, 2005}, pages = {8694-8698}, abstract = {Isolation and characterization leaf volatiles in Anemopsis californica (Nutt.) Hook. and Arn. (A. californica) was performed using steam distillation, solid-phase microextraction, and supercritical fluid extraction. Thirty-eight compounds were detected and identified by gas chromatography; elemicin was the major component of the leaf volatiles. While the composition of the leaf volatiles varied with method of extraction, sabinene, 1,8-cineole, piperitone, methyl eugenol, and elemicin were usually present in readily detectable amounts. Greenhouse-reared clones of a wild population of A californica had an identical leaf volatile composition with the parent plants. Steam-distilled oil had antimicrobial properties against 3 (Straphylococcus aureus, Streptococcus pneumoniae, and Geotrichim candidum) of 11 microbial species tested. Some of this bioactivity could be accounted by the oil. http://pubs.acs.org/cgi-bin/article.cgi/jafcau/2005/53/i22/pdf/jf0511244.pdf}, keywords = {antimicrobial, leaf, steam distillation}, url = {/files/bibliography/05-011.pdf}, author = {A. Medina and M.E. Lucero and Holguin, F.O. and Richard E. Estell and Posakony, J.J. and Simon, J. and M. A. O{\textquoteright}Connell} } @conference {50581, title = {Carbon in Desert Soils at Multiple Time Scales}, booktitle = {Ecological Society of America 90th Annual Meeting}, year = {2005}, month = {August 7-12, 200}, pages = {447-448}, address = {Montreal, Quebec, CANADA}, abstract = {In contrast to soils of humid regions, which contain carbon as organic matter only, soils of arid regions contain carbon as organic matter as well as calcium carbonate (i.e., inorganic carbon). Both organic and inorganic carbon in desert soils occur in pools through which carbon is driven by interacting physical, chemical, and biological processes. Organic carbon is derived from the decomposition of photosynthetic tissue and is removed from soil via microbial decomposition. Inorganic carbon is derived from the precipitation of bicarbonate with calcium (as well as from dust deposition) and is removed from the soil via dissolution and leaching. The amount of organic carbon in desert soils increases with time until it reaches equilibrium with its bioclimatic environment. The amount of inorganic carbon in desert soils also increases with time, but in contrast to organic carbon, it continues to accumulate with time until the soil is destroyed by erosion or until a climatic change occurs. Patterns of carbon moving through these two pools come into focus at multiple scales. At the diurnal scale, soil CO2 emissions have amplitudes up to 80 mg CO2/square meter/hour; at the yearly scale, amplitudes can be up to 200 mg CO2/square meter/hour. At the century scale, soil organic carbon follows major vegetation changes, such as the replacement of grasslands by shrublands. At the millennial scale, bother organic and inorganic carbon pools are controlled by glacial-interglacial cycles. At all scales, carbon in desert soils mirrors the temporal dynamics of ecological processes.}, keywords = {calcium, carbon, carbonate, inorganic, organic}, author = {Curtis H. Monger and R. A. Kraimer and A. Serna-Perez and Jeffrey E. Herrick} } @conference {50589, title = {Cross Scale Interactions and Spatial Nonlinearities: An Interdisciplinary Framework}, booktitle = {Ecological Society of America 90th Annual Meeting}, year = {2005}, month = {August 7-12, 200}, pages = {504}, address = {Montreal, Quebec, CANADA}, abstract = {Thresholds caused by nonlinear interactions and feedbacks across spatial scales are common features of ecological and physical systems. Spatial nonlinearities (i.e., acceleration or deceleration in the rate of change as the spatial extent expands) challenge the ability of ecologists to understand and predict system behavior at one scale based on information obtained at finer or broader scales. Thus, cross-scale interactions often result in {\textquotedblleft}surprises{\textquotedblright} with severe consequences for the environment (e.g., wildfire, pest outbreaks, state changes) and human welfare (e.g., spread of infectious diseases). Alternatively, cross scale interactions may be beneficial, such as accelerated recovery of vegetation following fire. In both cases, fine scale processes propagate nonlinearly to have unexpected effects at broader spatial scales. In many cases, climate variability and its effects on ecosystems, is a mechanism for cross-scale synchronization of ecosystem pattern and process.Identification of the key processes generating the nonlinear behavior is often problematic. We present a conceptual framework for understanding and forecasting events that result from cross scale interactions. We provide support for our framework using both historical (the Dust Bowl) and current examples (wildfires, invasive species). This paper provides the introduction for a series of papers on the importance of cross scale interactions to the dynamics of a variety of ecological systems.}, keywords = {ecological, nonlinear, sptaial, thresholds}, author = {Debra C. Peters and Brandon T Bestelmeyer} } @conference {50600, title = {Comparing Measurement Methods for CO2 Emissions from Chihuahuan Desert Soil}, booktitle = {Proceedings II Simposio Internactional de Manejo de Pastizales}, year = {2005}, month = {April 20-21, 200}, pages = {79}, address = {Zacatecas, Zac., Mexico}, abstract = {Las emisiones de CO2 del suelo son necesarias para estimar el balance de carbono, mineralizaci{\'o}n, actividad microbial y de ra{\'\i}ces y para medir los efectos del manejo, por lo que su medici{\'o}n es primordial. Con la finalidad de comparar m{\'e}todos de medici{\'o}n de CO2 del suelo se realizo este experimento en la Jornada LTER. Los m{\'e}todos comparados fueron una soluci{\'o}n de hidr{\'o}xido de sodio 0.4M (NaOH), sosa c{\'a}lcica s{\'o}lida (SCS) y analizador de gases de rayos infrarrojos (AGRI). El experimento, con una duraci{\'o}n de 24 horas, se realizo en una comunidad de dunas de mesquite del Desierto Chihuahuense. La medici{\'o}n de CO2 se efectu{\'o} en dos posiciones, una al pie de la duna (Arbusto) y la otra a 2 metros de ella (Inter espacio), y en dos condiciones de humedad; seca (S) y h{\'u}meda (H). La combinaci{\'o}n de fuentes de variaci{\'o}n (m{\'e}todo, posici{\'o}n y condici{\'o}n de humedad) produjo 12 tratamientos que se repitieron en 5 diferentes dunas de mesquite. La emisi{\'o}n de CO2 fue determinada al final del experimento en NaOH y SCS y a diferentes intervalos de tiempo (en horas) en AGRI. La humedad del suelo se estimo por el m{\'e}todo gravim{\'e}trico al final del experimento. La informaci{\'o}n fue sujeta a ANDEVA y comparaci{\'o}n de medias utilizando SAS. En promedio las emisiones de CO2 del suelo medidas con el m{\'e}todo SCS fueron mayores (P = 0.05) a las emisiones de CO2 medidas por los m{\'e}todos NaOH {\'o} AGRI. No se encontr{\'o} diferencia entre las emisiones de CO2 del suelo medidas con NaOH y AGRI. Dentro de cada m{\'e}todo no hubo diferencias en las emisiones de CO2 del suelo entre las combinaciones de posici{\'o}n y condici{\'o}n de humedad a pesar de existir diferencias en contenido de humedad del suelo (P = 0.05) a trav{\'e}s de todos los m{\'e}todos de medici{\'o}n de CO2.}, keywords = {Chihuahuan, CO2, emissions, measurement, methods, microbial}, author = {A. Serna-Perez and Jeffrey E. Herrick and Curtis H. Monger and K. Crossland} } @proceedings {50605, title = {Current and future options for the use of remote sensing for rangeland management and monitoring}, year = {2005}, month = {April 20-21, 200}, pages = {84}, address = {Zacatecas, Mexico}, abstract = {Many of the existing rangeland health, remotely sensed products are derived from medium spatial resolution imagery and, while these products may provide useful ancillary information for rangeland management, they do not provide information at spatial resolution that is fine enough to correspond with the field assessments conducted by rangeland management specialists. In this paper we present an overview of ongoing remote-sensing research at the ARS-USDA Jornada Experimental Range (the Remotely Sensed Indicators and Stratification (RSIS) Project) that aims to provide (1) relevant contextual information for optimizing ground sampling for field assessments and (2) accurate, fine-resolution vegetation maps and associated analyses for deriving remotely sensed indicators of rangeland health. Further, we provide a synopsis of other remote sensing activities at the Jornada Experimental Range.}, keywords = {management, monitoring, rangeland, remote sensing}, author = {Caitriana Steele and Andrea S. Laliberte and Brandon T Bestelmeyer and Jeffrey E. Herrick and A. Rango} } @conference {50611, title = {Coastal nutrient and pollutant dynamics: The interaction of fast and slow processes.}, booktitle = {Ecological Society of American Abstracts Annual Meeting}, year = {2005}, month = {August 7, 2005}, pages = {CDROM}, abstract = {The North basin of the Caspian Sea is cleaner now than in the 1980s and early 1990s and cleaner than widely assumed. Agricultural inputs of nutrients declined with the break-up of the USSR. The Volga River is the main source (more than 80\%) of both nutrients and pollutants to the North Caspian. Nutrient fluxes to the North Caspian through the Volga are controlled by upstream dams and other river control structures and by the the downstream processes in the large Volga Delta. The residence time of water in the North Basin is about 1-3 years. The Volga river inputs control the salinity of the North basin which ranges from 0 ppt at the river mouths to approximately 12 ppt at the boundary with the mid Caspian. The North Caspian is highly productive, and production is usually P-limited, but occasionally co-limited by N and P. Nitrogen inputs average 800,000 tons/year, but export to the mid caspian is about 600,000 tons/year. Phytoplankton primary production contributes more than 50\% of the organic carbon to the ecosystem (14-22 TG C /yr.), with the remainder flowing into the basin through the Volga and Ural rivers. The annual high flow of the Volga River is usually in late spring, somewhat delayed and decreased by regulation for flood control and human use. The extent of seasonal ice cover is weather dependent, but ice covers most of the North Basin in cooler years. Retreat of the ice is accompanied by an early spring phytoplankton bloom which is sustained by the spring flush from the Volga. The shallow well}, keywords = {Caspian Sea, coastal, nutrient, pollutant}, author = {S. Tartowski and V. Bashkin} } @conference {50617, title = {Cryobionts in Snow and Ice Observed with Low Temperature Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM)}, booktitle = {Geological Society of American Meeting}, volume = {37}, number = {7}, year = {2005}, month = {October 18, 2005}, pages = {267, Paper No. 118-6}, abstract = {Numerous studies have isolated and identified hundreds of species of nival fauna. Some of these species were true cryobionts that inhabited adverse alpine environments, others were merely aeolian fauna that were passively deposited on snowfields by updrafts. Because of the extreme environments in which these organisms are found, studying them in situ is very difficult. However, because similar environments may exist or previously existed on Mars, the growth and analogous fauna could have been supported in the Martian milieu. For this reason, identifying these organisms and understanding the ultrastructural features that enable them to survive in adverse environments is an important endeavor. Recently, our laboratory has been successful in samplying, shipping, storing and imaging snow crystals and ice grains with a technique known as low temperature SEM. Briefly, this technique consists of collecting samples at remote sites and freezing them in liquid nitrogen. All further manipulations, including imaging, are performed at near liquid nitrogen temperatures, thereby insuring that no re-crystallization or sublimation can occur. At several of the collection sites, bacteria, fungi, algae and ice worms were unexpectedly included with the snow and ice samples. As a result, the surface features of these frozen organisms could be observed in true three-dimensions at magnifications of 50,000 times. Furthermore, following imaging in the SEM, algae could be recovered and chemically fixed by freeze-substitution for examination in a TEM where observations revealed the internal ultrastructural features of the cells. We believe that these results demonstrate important new techniques for in situ studies of nival fauna.}, keywords = {cryobionts, nival fauna, snowfields}, url = {http://gsa.confex.com/gsa/htsearch.cgi?words=Cryobionts\&action=search\&formaction=htsearch.cgi\&meetingid=\&dir=\&override=\&passedyear=2005\&passedmeeting=all\&exclude=\%7C\%2Fprogram\%7C\%2Fmeeting\%7C\%2Fsearch.html\%7C\%2Fprelim\&config=gsa\&method=or\&format=bui}, author = {W.P. Wergin and J. Foster and A. Rango and E. G. Josberger and E. R. Erbe and Murphy, C.A. and C.D. Pooley} } @article {50655, title = {A combined modeling and measurement technique for estimating wind-blown dust emissions at Owens (dry) Lake, CA}, journal = {Journal of Geophysical Research}, volume = {109}, year = {2004}, note = {//NONE//NONE// Listed in LTER IV 2004 annual report}, month = {2004}, pages = {1-23}, abstract = {

The problem of dust emissions from playa sources is an important one both in terms of human health and in terms of global dust issues, distribution of loess, and mineral cycling. A refined method of modeling atmospheric dust concentrations due to wind erosion was developed using real-time saltation flux measurements and ambient dust monitoring data at Owens Lake, California. This modeling method may have practical applications for modeling the atmospheric effects of wind erosion in other areas. Windblown dust from the Owens Lake bed often causes violations of federal air quality standards for particulate matter (PM10) that are the highest levels measured in the United States. The goal of this study was to locate dust source areas on the exposed lake bed, estimate their PM10 emissions, and use air pollution modeling techniques to determine which areas caused or contributed to air quality violations. Previous research indicates that the vertical flux of PM10 (Fa) is generally proportional to the total horizontal saltation flux (q) for a given soil texture and surface condition. For this study, hourly PM10 emissions were estimated using Fa = K' {\texttimes} m15, where m15 is the measured sand flux at 15 cm above the surface, and K' was derived empirically by comparing air quality model predictions to monitored PM10 concentrations. Hourly sand flux was measured at 135 sites (1 km spacing) on the lake bed, and PM10 was monitored at six off-lake sites for a 30 month period. K' was found to change spatially and temporally over the sampling period. These changes appeared to be linked to different soil textures and to seasonal surface changes. K' values compared favorably with other Fa/q values measured at Owens Lake using portable wind tunnel and micrometeorological methods. Hourly trends for the model-predicted PM10 concentrations agreed well with monitored PM10 concentrations. Dust production was estimated at 7.2 {\texttimes} 104 t of PM10 for a 12 month period. A single storm accounted for 9\% of the annual dust emissions at 6.5 {\texttimes} 103 t. The modeling results were used to identify 77 km2 of dust-producing areas on the lake bed that will be controlled to attain the federal air quality standard for PM10.

}, keywords = {aeolian processes, dust emissions, aeolian processes, Owen Lake, article, articles, journal, journals, model, dust emission, wind transport, Owens Lake}, isbn = {F01003, doi:10.1029/2003JF000025}, doi = {10.1029/2003JF000025}, url = {files/bibliography/JRN00403.pdf}, author = {D. E. Gillette and Ono, D. and Richmond, K.} } @article {50674, title = {Comparison of land surface emissivity and radiometric temperature derived from MODIS and ASTER sensors}, journal = {Remote Sensing of Environment}, volume = {90}, number = {2}, year = {2004}, month = {March 30, 2004}, pages = {137-152}, abstract = {

This study compares surface emissivity and radiometric temperature products derived using data collected with the MODerate resolution Imaging Spectroradiometer (MODIS) and Advanced Spaceborne Thermal Emission Reflectance Radiometer (ASTER) sensors, on the Earth Observation System (EOS) - Terra satellite. Two study sites were selected: a semi-arid area located northern Chihuahuan desert in the USA, and a savanna landscape located in central Africa. Atmospheric corrections were performed using different strategies that were driven by the instrumental features of each sensor. The MODIS products were then computed using a designed Temperature Independent Spectral Indices of Emissivity (TISIE) method. The ASTER products were derived using the Temperature Emissivity Separation (TES) algorithm. The MODIS and ASTER radiometric temperature products were in good agreement when the atmospheric corrections were similar, with differences lower than 0.7 K. The comparison of emissivity estimates was performed for MODIS / ASTER matching bands, at 8.5 and 11 micrometer. The emissivity estimates agreed well at 11 micrometer, although the range of the MODIS values was larger than that of the ASTER values. At 8.5 micrometer, the differences between the estimates were larger as compared to 11 micrometer, but the comparison results were acceptable, and the ranges of emissivities from both sensors were the same.

}, doi = {10.1016/j.rse.2003.11.015}, author = {Jacob, F. and Petitcolin, F. and T. J. Schmugge and Vermote, E. and A.N. French and Ogawa, K.} } @article {50699, title = {A conceptual model for determining soil erosion by water}, journal = {Earth Surface Processes and Landforms}, volume = {29}, number = {10}, year = {2004}, note = {//Walnut Gulch//LTER IV//corrected 05/14/2008; PDF on file}, month = {2004}, pages = {1293-1302}, abstract = {

Current estimates of rates of soil erosion by water derived from plots are incompatible with estimates of long-term lowering of large drainage basins. Traditional arguments to reconcile these two disparate rates are flawed. The flux of sediment leaving a specified area cannot be converted to a yield simply by dividing by the area, because there is no simple relationship between flux and area. Here, we develop an approach to the determination of erosion rates that is based upon the entrainment rates and travel distances of individual particles. The limited available empirical data is consistent with the predictions of this approach. Parameterization of the equations to take account of such factors as gradient and sediment supply is required to proceed from the conceptual framework to quantitative measurements of erosion. However, our conceptual model solves the apparent paradox of the sediment delivery ratio, resolves recent discussion about the validity of erosion rates made using USLE erosion plots, and potentially can reconcile erosion rates with known lifespans of continents. Our results imply that previous estimates of soil erosion are fallacious. Copyright {\textcopyright} 2004 John Wiley \& Sons, Ltd.

}, keywords = {article, hydrology, erosion rates, hydrology, sediment delivery, hydrology, soil erosion, hydrology, water erosion, journal, model, hydrology, model, soil erosion, model, water erosion}, isbn = {DOI: 10.1002/esp.1096}, doi = {10.1002/esp.1096}, url = {files/bibliography/JRN00404.pdf}, author = {A.J. Parsons and John Wainwright and Mark D. Powell and Kaduk, Jorg and Richard E. Brazier} } @article {50700, title = {Cross-scale interactions, nonlinearities, and forecasting catastrophic events}, journal = {Proceedings of the National Academy of Sciences}, volume = {101}, number = {42}, year = {2004}, month = {October 19, 2004}, pages = {15130-15135}, abstract = {

Catastrophic events share characteristic nonlinear behaviors that are often generated by cross-scale interactions and feedbacks among system elements. These events result in surprises that cannot be easily predicted based on information obtained at a single scale. Progress to date on catastrophic events has focused on one of two areas: (1) nonlinear dynamics through time without an explicit consideration of spatial connectivity, and (2) spatial connectivity and the spread of contagious processes without a consideration of cross scale interactions and feedbacks. These approaches have rarely ventured beyond traditional disciplinary boundaries. We provide an interdisciplinary, conceptual and general mathematical framework for understanding and forecasting nonlinear dynamics through time and across space. We illustrate the generality and utility of our approach using new data and a recasting of published data from ecology (wildfires, desertification), epidemiology (infectious diseases) and engineering (structural failures). We show that decisions that minimize the likelihood of catastrophic events must be based on cross-scale interactions, and such decisions will often be counter-intuitive. Given the continuing challenges associated with global change, approaches that cross disciplinary boundaries to include interactions and feedbacks at multiple scales are needed to increase our ability to predict catastrophic events and to develop strategies for minimizing their occurrence and impacts. Our framework is an important step in developing predictive tools and designing new experiments to examine cross-scale interactions.

}, keywords = {catastrophic events, cross-scale interactions, forecasting, nonlinearities}, doi = {10.1073/pnas.0403822101}, url = {files/bibliography/JRN00406.pdf}, author = {Debra C. Peters and R.A. Pielke and Brandon T Bestelmeyer and C.D. Allen and Seth M. Munson and Kris Havstad} } @article {50759, title = {Canopy attributes of desert grassland and transition communities derived from multiangular airborne imagery}, journal = {Remote Sensing of Environment}, volume = {85}, number = {3}, year = {2003}, month = {May 30, 2003}, pages = {339-354}, abstract = {

Overlapping multi-angular spectral reflectance images were collected over desert grassland and grass-shrub transition communities (USDA, ARS, Jornada Experimental Range, Las Cruces, NM) using a DuncanTech multispectral digital camera mounted on a tilting bracket installed in an ARS research aircraft. Flightlines were oriented in the principal plane with three flights providing observations at three solar zenith angles (37 deg, 47 de and 60 deg). The 0.65um band images were calibrated to spectral radiance (W m2 um-1 sr-1) using laboratory measurements, corrected for atmospheric attenuation using the 6Sv4.2 code and resampled to a 2m UTM grid. The surface reflectance estimates were checked with air- and ground-based observations of 8m2 reference tarps. The images were convolved with a 50m2 pseudo-Gaussian point spread function and sampled at 25m to simulate samples from a sensor with a larger instantaneous field-of-view to properly ycapture the bidirectional reflectance distribution function (BRDF; intrinsic surface length scales are greater than 10m). A BRDF model based on geometric optics and volume scattering functions was developed to account for variation in directional reflectance signal with viewing and illumination angles. It was adjusted to the set of multi-angular observations for each location using the Hooke and Jeeves algorithm (1961), inverting the model for 2 (facet area index and plant protrusion density) and 3 parameters (facet area index, plant protrusion density and width) simultaneously and for these parameters plus a crown shape factor with stepwise inversion of each parameter sequentially. The retrieved parameter maps were assessed for value distributions and compared with 1m panchromatic and 4m vegetation index images from the IKONOS satellite.

}, doi = {10.1016/S0034-4257(03)00012-9}, url = {/files/bibliography/03-001.pdf}, author = {M. Chopping and A. Rango and Kris Havstad and Schiebe, F.R. and Jerry Ritchie and T. J. Schmugge and A.N. French and McKee, L.G. and Davis, M.R.} } @article {50766, title = {Collecting, shipping, storing and imaging snow crystals and ice grains with low temperature scanning electron microscopy}, journal = {Microscopy Research and Technique}, volume = {62}, number = {1}, year = {2003}, month = {September 1, 200}, pages = {19-32}, abstract = {Methods to collect, transport and store samples of snow and ice have been developed that enable detailed observations of these samples with a technique known as low temperature scanning electron microscopy (LTSEM). This technique increases the resolution and ease with which samples of snow and ice can be observed, studied and photographed. Samples are easily collected in the field and have been shipped to the electron microscopy laboratory by common air carrier from distances as far away as 5,000 miles. Delicate specimens of snow crystals and ice grains survive the shipment procedures and have been stored for as long as 3 years without undergoing any structural changes. The samples are not subjected to the melting or sublimation artifacts. LTSEM allows individual crystals to be observed for several hours with no detectable changes. Furthermore, the instrument permits recording of photographs containing the parallax information necessary for three-dimensional imaging of the true shapes of snowflakes, snow crystals, snow clusters, ice grains and interspersed air spaces. This study presents the detailed descriptions of the procedures that have been used successfully in the field and the laboratory to collect, ship, store and image snow crystals and ice grains.}, url = {/files/bibliography/03-041.pdf}, author = {E. R. Erbe and A. Rango and J. Foster and E. G. Josberger and C.D. Pooley and W.P. Wergin} } @article {50775, title = {Crossroads of animal, plant, and microbial physiological ecology}, journal = {BioScience}, volume = {53}, year = {2003}, note = {//??//LTER IV//}, month = {2003}, pages = {256-259}, abstract = {

Animal, plant, and microbial ecophysiologists have diverged greatly in the last few decades in the principal research questions they address (e.g., global change versus evolution), in the methods they use, and even in the professional societies to which they belong. Two symposia in 2001 brought these diverse groups together, with presentations by researchers who study two or three kingdoms in intimate interaction. The second symposium, the subject of this report, was sponsored by the Ecological Society of America{\textquoteright}s Physiological Ecology section. Several of the presentations showed, among other things, commonalities in chemical signaling among kingdoms, as well as exploitation of such signals and other metabolic pathways by parasites and their hosts. These and other important findings from such interkingdom and interdisciplinary research can help explain why current functional groups exist.

}, keywords = {animal physiology, ecology, microbial physiology, plant physiology}, doi = {10.1641/0006-3568(2003)053[0256:COAPAM]2.0.CO;2 }, url = {files/bibliography/JRN00379.pdf}, author = {V. P. Gutschick and Bloom, A. J.} } @proceedings {50784, title = {A cost-effective soil and vegetation monitoring protocol for adaptive management}, year = {2003}, month = {July 26-August 1}, pages = {704-706}, address = {Durban, South Africa}, abstract = {Rangeland monitoring is frequently limited by high costs and low relevance to management. Furthermore, most protocols continue to focus on the average status of a single ecosystem property, such as forage production, while our evolving understanding of nonequilibrium dynamics and local threshold responses require information on how complex ecosystem processes vary across the landscape over time (National Research Council 1994; Society for Range Management 1995). We describe a simple, quantitative monitoring protocol designed to be used in conjunction with state and transition models to increase management effectiveness at multiple spatial and temporal scales (Herrick et al. 2003). The protocol integrates ground-based soil and vegetation measurements with simple remote sensing technologies (e.g., aerial photographs). This approach allows relatively large areas to be monitored while focusing most of the effort on those areas with the highest probability of change. The protocol also clearly distinguishes between long-term and short-term indicators. Long-term indicators are used to monitor relatively persistent management effects, while short-term indicators are used to adjust management on a daily to seasonal basis.}, keywords = {adaptive management, cost-effective, monitoring protocol, soil, vegetation}, url = {/files/bibliography/03-030.pdf}, author = {Jeffrey E. Herrick and A. Rango and Kris Havstad} } @article {JRN55000, title = {Climate change and biotic invasions: a case history of a tropical woody vine}, journal = {Biological Invasions}, volume = {5}, year = {2003}, pages = {147-165}, chapter = {147}, abstract = {

The impacts of climate change in the potential distribution and relative abundance of a C3 shrubby vine, Cryptostegia grandiflora, were investigated using the CLIMEX modelling package. Based upon its current naturalised distribution, C. grandiflora appears to occupy only a small fraction of its potential distribution in Australia under current climatic conditions; mostly in apparently sub-optimal habitat. The potential distribution of C. grandiflora is sensitive towards changes in climate and atmospheric chemistry in the expected range of this century, particularly those that result in increased temperature and water use efficiency. Climate change is likely to increase the potential distribution and abundance of the plant, further increasing the area at risk of invasion, and threatening the viability of current control strategies markedly. By identifying areas at risk of invasion, and vulnerabilities of control strategies, this analysis demonstrates the utility of climate models for providing information suitable to help formulate large-scale, long-term strategic plans for controlling biotic invasions. The effects of climate change upon the potential distribution of C. grandiflora are sufficiently great that strategic control plans for biotic invasions should routinely include their consideration. Whilst the effect of climate change upon the efficacy of introduced biological control agents remain unknown, their possible effect in the potential distribution of C. grandiflora will likely depend not only upon their effects on the population dynamics of C. grandiflora, but also on the gradient of climatic suitability adjacent to each segment of the range boundary.

}, keywords = {biological control, climate change, CLIMEX, Cryptostegia, global change, invasion, modelling, range shifts, weed}, url = {files/bibliography/03-036.pdf}, author = {Kriticos, D. J. and Sutherst, R. W. and Joel R. Brown and Adkins, S.W. and Maywald, G. F.} } @article {50854, title = {Community structure along elevation gradients in headwater regions of longleaf pine savannas}, journal = {Plant Ecology}, volume = {160}, number = {1}, year = {2002}, month = {May 1, 2002}, pages = {61-78}, abstract = {Quantitative descriptions of vegetation patterns and relationships with substrate characteristics at localized scales have received less attention than regional levels. Our primary objective was to examine the distributions of herbs and shrubs/trees along local topographic gradients in headwater regions of longleaf pine savannas in the southeastern United States. We also examined whether herb patterns were structurally similar to those of shrubs/trees along the same topographic gradients and whether patterns were correlated with edaphic factors. Abundance data were collected within quadrats placed along transects from upslope savannas through mid-slope seepage bogs into lower-slope shrub/tree zones within Louisiana and Florida. Beta-flexible cluster analysis and nonmetric multidimensional scaling were used to delineate herbaceous species communities. Ordination was performed separately on shrub/tree abundance data. The herb-based classifications were also used to delineate shrub/tree communities, providing an indirect means of comparing herb to shrub/tree distributions. In Louisiana, 3 herbaceous communities were sharply delineated along elevation gradients of several meters and were strongly correlated with soil moisture. In Florida, 3 similar herbaceous communities were less discrete along elevation gradients of <1 meter. In both regions, shrub/tree distributions were much broader and appeared less sensitive than herbs to changes in environmental gradients. Coefficients of variation indicated that herbaceous species were more narrowly distributed than shrubs/trees along localized elevation gradients in both Louisiana and Florida. Alterations of fire regimes may have resulted in expanded distributions of shrubs/trees but not herbs.}, url = {http://www.springerlink.com/media/e2wqmq6wtp5uug8nfv5q/contributions/x/d/l/p/xdlppcpceq4cyetp.pdf}, author = {Drewa, P.B. and Platt, W.J. and Moser, E.B.} } @proceedings {50864, title = {Complexity, desertification and livestock production: Dancing with the winds of change}, year = {2002}, month = {September 19-21,}, pages = {1-4}, address = {Chihuahua, Mexico}, abstract = {During the last 150 years the Jornada Experimental Range has undergone a transition from desert grasslands to desert scrubland vegetation. This transition is characteristic of desertification, a process occurring in arid and semiarid regions worldwide. While livestock grazing is commonly isolated as the sole driver of desertification in the northern Chihuahuan Desert, it appears that actual causes are complex and difficult to untangle. Principal factors thought to cause current desertified conditions are shifts in seasonal precipitation with winter precipitation favoring shrubs and summer rainfall favoring grasses. Increasing CO2 may have a fertilization effect that favors C3 shrubs over C4 grasses. Human effects on mammalian predator-prey dynamics may have caused alterations in small herbivore populations that normally dampen oscillations in plant demographics. Whether current trends in desertification are due to human or non-human forces is, at present, indeterminable. What is certain is that we live in an environment that is complex, chaotic, and at times catastrophic. Our world is dynamic, constantly evolving, and rarely at equilibrium. Future success will result because of a society{\textquestiondown}s ability to adapt and innovate in response to change, and to do so within an ethical framework that creates potential benefit to current and future societies.}, author = {E.L. Fredrickson and Amy L. Gonzalez} } @conference {50883, title = {Comprehending complexity together with the public: Practical strategies for improving rangeland conservation, restoration and management}, booktitle = {87th Annual Meeting, Ecological Society of America}, year = {2002}, month = {August 4-9, 2002}, pages = {25}, address = {Tucson, AZ}, abstract = {Rangeland ecosystems are complex, particularly when soil and climate are considered. Complexity is viewed as a liability when dealing with the public and scientific uncertainty often leads to uncertainties about the usefulness of science. Basic research is needed to reduce scientific uncertainties about the probable consequences of human intervention in arid and semiarid environments. Research is also needed to develop tools that can be used to more effectively communicate our evolving understanding. We will describe four successful approaches that illustrate how indicators and conceptual models based on basic research are being used to increase appreciation of ecological complexity, reduce environmental conflicts, and improve rangeland management: (1) monitoring and assessment workshops for ranchers, environmentalists and government agency personnel in the U.S. and Mexico, (2) development of ecological state and transition models, (3) implementation of integrated soil and vegetation management and monitoring plans, and (4) introduction of school children to ecological and experimental design concepts. All four of these approaches use indicators of basic ecosystem functions to help individuals and organizations with diverse goals and logistical constraints to understand and apply concepts including soil-vegetation feedbacks and ecological thresholds. Conceptual state and transition models are used to help explain how human management of fire, livestock and wildlife grazing and invasive species can have diverse effects on vegetation dynamics.}, keywords = {education, monitoring, rangeland, state-and-transition models}, author = {Jeffrey E. Herrick and Brandon T Bestelmeyer and McCarthy, P. and Brandon T Bestelmeyer and Kris Havstad and Melgoza, A. and A.J. Tugel} } @conference {50884, title = {Criteria for dynamic soil property selection for soil survey}, booktitle = {Annual Meeting, American Society of Agronomy-Crop Science Society of America-Soil Science Society of America}, volume = {CD-ROM}, year = {2002}, month = {November 10-14, }, pages = {Abstract No. S05-herrick162540-Poster}, address = {Indianapolis, IN}, abstract = {Reference data on dynamic soil properties are increasingly demanded by land managers, policy makers and the general public. We need properties that reflect both current capacity of the soil to support production and other ecosystem services and others that reflect capacity to maintain or increase the system{\textquestiondown}s potential to generate these services in the future. The properties must satisfy the three following criteria: (1) The relationship between the properties and the processes or functions they are intended to reflect should be clearly defined. (2) The properties should be easy to measure repeatably. Ideally, the properties should be measured in the field with simple tools. (3) The time required to complete the number of measurements required to detect a functionally significant difference in the property at a specified level of statistical significance should be minimized. We will illustrate how each criteria was evaluated for a field soil disaggregation test. We will list other criteria that should be considered in order to make the database as useful as possible. Some properties that do not meet all criteria may be sufficiently valuable to include in the database.}, author = {Jeffrey E. Herrick and A.J. Tugel} } @conference {50894, title = {Changes in phenolic compounds and organic matter in leaf litter from creosotebush [Larrea tridentata (Sess. \& Moc. ex Dc.) Cov.] and tarbush (Flourensia cernua dc.)}, booktitle = {55th Annual Meeting, Society for Range Management}, year = {2002}, month = {February 13-19, }, pages = {13}, address = {Kansas City, MO}, abstract = {Creosotebush and tarbush leaf litter contain phenolic compounds that may interact allelopathically with surrounding plants and soil biota. Our objective was to measure decline in phenolic concentrations with time. We placed fiberglass bags (1mm mesh) of litter beneath creosotebush and tarbush canopies. One set (two bags) was placed on the soil surface and one set was buried at 5 cm. Bags (six replicates, two duplicates) were collected at 0, 1, 3, 5, 7, 11, 15, 22, 30, 45, 60 and 90 days. Sets 1 and 2 (winter creosotebush and tarbush, respectively) were placed from February to April. Set 3, spring creosotebush, was placed from April to July. Set 1 lost organic matter at the rate of 0.000525 and 0.00406 mg/day; total phenolics, 0.209 and 0.111 mg/day; and, condensed tannins, 0.579 and 0.385 mg/day for surface and buried, respectively. Set 2 lost organic matter (0.00255 and 0.00392 mg/day) and total phenolics (0.449 and 0.517 mg/day) while concentrations of condensed tannins increased (0.0593 and 0.0929 mg/day) for surface and buried samples, respectively. Set 3 lost total phenolics (0.0470 and 0.151), nordihydroguaiaretic acid (0.165 and 0.210), condensed tannins (0.0863 and 0.0891), and organic matter (0.0247 and 0.0570 mg/day) for surface and buried, respectively. Percent organic matter loss was 1.99\% and 3.23\% for winter creosote, surface and buried samples, respectively; 2.31\% surface and 2.49\% buried for tarbush; and, 34.10\% and 75.27\% for surface and buried spring creosote, respectively. We demonstrated that concentrations of phenolic compounds decline in both surface and buried leaf litter.}, author = {P.W. Hyder and E.L. Fredrickson and Richard E. Estell and Kris Havstad and G.B. Donart} } @conference {50903, title = {A comparison of Dalea formosa oils isolated by steam distillation and by solid-phase microextraction}, booktitle = {Society for Range Management, New Mexico Section Winter Meeting}, year = {2002}, month = {January 8-10, 20}, pages = {Abstract 6}, address = {Las Cruces, NM}, abstract = {Dalea formosa Torr. (feather dalea, featherplume) was collected from the Jornada Experimental Range in south central New Mexico. Current year{\textquoteright}s growth was collected from 10 plants, all found within an approximate 50m radius of the GPS coordinates N 32 deg 40.645{\textquoteright} and W 106 deg 33.601{\textquoteright} during July 2001. Composite samples of the plants were steam distilled in triplicate, and the essential oil was analyzed using both GC-FID and GCMS. Compositions of plants collected from the same site were also examined using Solid Phase Microextraction (SPME). Mass spectra and retention indices were used to identify 58 previously described compounds. All of the compounds identified in the essential oil were also seen by SPME either by GCMS or by FID. Relative amounts of some compounds varied. Differences may be due to either sampling technique or harvesting time. The advantages of using SPME include the need for much less plant material, more rapid and dreproducible sample preparation, less opportunity for oxidation of volatiles to occur, and no need for the use of organic solvents.}, keywords = {comparison, Dalea formosa, solid-phase microextraction, steam distillation}, author = {M.E. Lucero and Richard E. Estell and Ruth L. Sedillo} } @conference {50908, title = {A comparison of steam distillation and solid-phase microextraction (SPME) for isolation of the Anemopsis californica volatiles}, booktitle = {Society for Range Management, New Mexico Section Winter Meeting}, year = {2002}, month = {January 8-10, 20}, pages = {8}, address = {Las Cruces, NM}, abstract = {Examination of the leaf volatiles of Anemopsis californica (Hook. \& Arn.) was performed using steam distillation and solid-phase micro-extraction (SPME)in order to compare the results generated by the two techniques . Gas chromatography, followed by mass spectral or flame ionization detection, was used for identification or quantification, respectively. Data reveals complex volatile profiles regardless of sample preparation technique. However, key differences in composition obtained by SPME and steam distillation were seen for several compounds. Elemicin, methyleugenol, beta-pinene, thymol and 2-E-hexanal were more abundant in steam distilled than in SPME extracts. With the exception of 2-E-hexanal, all compounds detected by steam distillation were also detected by SPME. In addition, 10 volatiles seen in the SPME profile were not detected in steam distillates. Results indicate SPME is a useful tool for extraction of diverse volatiles from A. californica. However, targeted isolations of the compounds named above may be more efficient by steam distillation.}, author = {A. Medina and M.E. Lucero and Richard E. Estell and M. A. O{\textquoteright}Connell} } @conference {50907, title = {Composition and antimicrobial activity of the essential oil of Anemposis californica}, booktitle = {Annual Phytochemical Society of North America Conference}, year = {2002}, month = {2002}, pages = {60 (BP-2)}, address = {Merida, Mexico}, abstract = {Anemopsis californica, native to the Southwest US, is commonly known as yerba mansa. The leaves and roots have traditionally been used to alleviate pain, inflammation, and fungal infections. Isolation of leaf volatiles of A. californica (Hook. \& Arn) was performed using steam distillation and solid phase microextraction (SPME). GC followed by mass spectral and flame ionization detection were used for identification and quantification. The most abundant compounds in the steam distillation were: elemicin (53.1\%), piperitone (11.0\%), and methyl-eugenol (6.9\%). The most abundant compounds detected in SPME extracts were piperitone (16.2\%), elemicin (13.2), alpha-pinene (11.7\%), 1,8-cineole (10.5\%), beta phellandrene (8.6\%), (E)-caryophyllene (8.2\%), methyl-eugenol (5.1\%) and sabinene (5.1\%). The essential oil exhibited antimicrobial activity against: Staphylococcus aureus, Streptococcus pneumoniae and Geotrichim candidum.}, author = {A. Medina and M.E. Lucero and M. A. O{\textquoteright}Connell} } @conference {50909, title = {Comparing and contrasting scaling approaches across ecological disciplines: case studies of vegetation, biogeochemical and animal dynamics}, booktitle = {17th Annual Symposium, US-International Association for Landscape Ecology}, year = {2002}, month = {April 23-26, 200}, pages = {88-89}, abstract = {Numerous approaches have been taken to evaluate spatial scaling relationships in ecology. These approaches can be generalized into three categories: those that are nonspatial, those that are spatially explicit but not spatially interactive, and those that are both spatially explicit and spatially interactive. While it is relatively easy to categorize a given study within these three approaches, a more general perspective comparing and contrasting how these approaches are used within different ecological disciplines is largely lacking. Here we compare and contrast case studies related to vegetation, biogeochemical and animal dynamics, discuss the implications of selecting a given approach, and note insights that can be obtained from a cross-disciplinary perspective. Understanding the similarities and differences among scaling approaches is particularly important in cases where processes from different disciplines need to be coupled to one another. An example of such couplings and their associated scale dependencies are highlighted by a case study in which drought produces vegetation mortality (vegetation dynamics) which was initially and subsequently exacerbated by grazing (animal dynamics) and has triggered large increases in runoff, erosion, and losses of carbon and nutrients (biogeochemistry). Our overview provides ideas for comparing scaling approaches while being cognizant of implicit assumptions and offers broader insights into scaling relationships across disciplines in ecology.}, author = {K. A. Mitchell and David D. Breshears and C.D. Allen and Brandon T Bestelmeyer and Gross, J.E.} } @proceedings {50933, title = {Comparative satellite capabilities for remote sensing of snow cover in the Rio Grande Basin}, year = {2002}, month = {May 20-23, 2002}, pages = {21-26}, address = {Granby, CO}, abstract = {From 1972 until near the end of the 20th century, the use of satellite data for snow cover mapping was a viable approach under certain conditions. The spatial resolution of Landsat and the temporal frequency of NOAA-AVHRR (National Oceanic and Atmospheric Administration - Advanced Very High Resolution Radiometer) were optimum or possibly better than required individually but seldom could they be exploited together. Now, with the launch of Terra, the forthcoming launch of Aqua and numerous private satellites, both adequate spatial resolution and temporal frequency is available for mapping most size basins. When these date are used in sub-pixel mapping algorithms, detailed snow cover representations in basins smaller than 10 km2 are possible. Probably the best snow cover mapping sensor for combining reasonably high resolution (250 m) and frequent coverage (daily) is MODIS (Moderate Resolution Imaging Spectroradiometer), on board both Terra and Aqua platforms, but the choices of sensors or satellites are numerous with most of the data being readily available to users. Comparison of the spatial resolution, observational frequency, feature detection, suitability for snowmelt runoff models and cost will be illustrated using different size sub-basins of the Rio Grande.}, url = {/files/bibliography/02-080.pdf}, author = {A. Rango and E. Gomez-Landesa and M. Bleiweiss} } @proceedings {50966, title = {Carbon transport by symbiotic fungi in fourwing saltbush, Atriplex canescens (Pursh) Nutt.}, volume = {RMRS P-21}, year = {2001}, month = {June 13-15, 2000}, pages = {291-294}, publisher = {USDA Forest Service Proceedings RMRS-P-00.2001}, address = {Provo, UT}, abstract = {Mycorrhizal fungi enhance the nutrition and survival of host plants in native ecosystems. Arid rangelands severely challenge plants because of chronic nutrient and water stress. Fourwing saltbush, Atriplex canescens (Pursh) Nutt., a dominant and important shrub of western arid rangelands, generally considered to be non-mycorrhizal, is more extensively colonized by dark septate (DS) fungal endophytes than by traditional mycorrhizal fungi. Roots of fourwing saltbush colonized by DS fungi were stained with sudan IV and analyzed with differential interference microscopy which revealed extensive internal colonization by vacuolated hyaline hyphae that is not evident using conventional fungus staining methods. Fungal vacuoles accumulated substantial quantities of lipids in the sieve elements and cortex when roots were physiologically active. The widespread colonization of fourwing saltbush by DS fungi and their extensive accumulation of lipids ssuggests that these fungi transport and manage carbon in arid ecosystems. Their potential role in ecosystems stability is discussed.}, keywords = {Atriplex canescens, carbon, fourwing saltbush, Mycorrhizal fungi, plant survival}, url = {/files/bibliography/01-006.pdf}, author = {J.R. Barrow} } @conference {51021, title = {Comparison of LCTA with an integrated soil and vegetation monitoring protocol for monitoring grassland, shrubland, and savanna ecosystems}, booktitle = {10th Annual Integrated Training Area Management Workshop}, year = {2001}, month = {August 27-31, 20}, pages = {99}, address = {Nashville, TN}, abstract = {We compared the LCTA vegetation monitoring methods with a new integrated soil and vegetation rangeland monitoring protocol that was developed specifically for arid and semi-arid grasslands, shrublands and savannas and has been adapted to more mesic grassland ecosystems. Data were collected by applying both methods in southern New Mexico. We then evaluated the cost (time efficiency) of the two protocols. In addition, we assessed the ability of both methods to produce indicators that relay meaningful information about ecosystem function and the effects of disturbance at each site. Specifically, we compared each protocol{\textquoteright}s ability to detect changes in three ecosystem attributes: soil and site stability, hydrologic function and biotic integrity. Preliminary comparisons indicated the new methods are more sensitive to changes in soil and site stability and hydrologic function. This is due to the new protocol{\textquoteright}s inclusion of soil measurements sand measurements of spatial patterns in vegetation. The new methods also address a broader range of biotic integrity indicators through the inclusion of soil measurements.}, author = {Laura M. Burkett and Jeffrey E. Herrick} } @article {50997, title = {Coupling use-dependent and use-invariant data for soil quality evaluation}, journal = {Journal of Soil and Water Conservation}, volume = {56}, number = {1}, year = {2001}, month = {January 1, 2001}, pages = {63-68}, abstract = {The estimated properties for soil survey map units typically are for only the major soil use. Users are provided only one set of soil properties. We consider the combination of use-invariant and use-dependent databases to produce composite records. The use-invariant data is determined by soil origin and genesis and is at most only slightly subject to change with use. .The use-dependent data is readily subject to change by use. Near-surface properties are particularly subject to change with use. Each use-invariant property is assigned a surficial exclusion zone within which the property is considered use-dependent and hence the standard interpretive record is not applicable. Both use-dependent and use-invariant properties are placed in one of five classes. Numerical rankings for quality evaluation are obtained by combining the placements for the several properties concerned. We use the term use-invariant for properties such as texture, depth to bedrock, etc. that change little if at all among different uses. Propertie that do change with use but are not recognized as doing so are not use-invariant. Rather, they are use-dependent but not so recognized. Thus, there are two kinds of use-dependent properties: those recognized and those that are not. There is a further consideration. The present database of use-invariant properties is useful in defining the potential range of values for use-dependent properties and the susceptibility of those properties to change with use. In short, the use-invariant information is necessary but not sufficient by itself to predict the use-dependent properties for soil quality evaluation.}, keywords = {soil quality evaluation, use-dependent data, use-invariant data}, url = {/files/bibliography/01-028.pdf}, author = {R. Grossman and D. S. Harms and C. Seybold and Pytlik, L.A. and Jeffrey E. Herrick} } @article {51016, title = {A comparison of single date and multitemporal satellite classification in a semi-arid grassland.}, journal = {Journal of Arid Environments}, volume = {49}, year = {2001}, note = {//?//LTER IV//}, month = {2001}, pages = {401-411}, abstract = {

Landsat Thematic Mapper (TM) satellite data were used to produce maps depicting ranges of major vegetation types at the Jornada Experimental Range, New Mexico, U.S.A. Single date and multitemporal classification accuracies were compared using vegetation ground data as references. Single date image classifications were more accurate than multitemporal images for mapping land cover types in this region. Use of single date imagery generally involves less expenditure of time and costs related to data acquisition and processing. Multitemporal images have improved classification accuracies in some landscapes; however, single date images may provide a reliable method for mapping vegetation cover in semi-arid environments.

}, keywords = {article, articles, classification, grassland, journal, journals, multitemporal, satellite}, doi = {10.1006/jare.2000.0771}, url = {files/bibliography/JRN00316.pdf}, author = {Langley, S. K. and Cheshire, H. M. and K. S. Humes} } @proceedings {51019, title = {Carbon sequestration and global warming}, year = {2001}, note = {//?//LTER IV//ProCite field[6]: in}, month = {2001}, address = {Universidad Juarez del Estado de Durango}, keywords = {abstract, abstracts, carbon, conference, conference proceedings, conferences, global warming, proceeding, proceedings}, author = {Curtis H. Monger and J. Martinez-Rios and R. A. Gallegos}, editor = {Navarro, J. and Calzada, C. and Martinez-Rios, A.} } @conference {51030, title = {Climatic triggers for nonlinear and threshold responses of rangelands}, booktitle = {86th Annual Meeting, Ecological Society of America}, year = {2001}, month = {August 6-10, 200}, pages = {31}, address = {Madison, WI}, abstract = {Climatic triggers to threshold responses have been observed for a number of ecosystem types, although our understanding and prediction of these responses remain limited. Our objective was to examine and synthesize the conditions under which climate is expected to trigger both larger and smaller than expected positive or negative ecosystem responses. These ecosystem "surprises" are related to interactions among properties of the climate (severity, duration, and frequency of extreme events), vegetation (e.g., species composition, age structure, and sex ratios) and soil (e.g., water-holding capacity, soil organic matter content). Management has important influences on the vegetation and soil that affect the ability of the ecosystem to respond to climatic events. Furthermore, thresholds observed at one spatial or temporal scale may or may not be observed at larger or smaller scales. We illustrate the importance of these interacting properties to ecosystem responses to climate across temporal and spatial scales using both paleoecological data and information from current vegetation for a number of ecosystem types. We then provide a general framework for understanding climatic triggers to threshold responses that can be used to guide research and assist in setting management priorities.}, author = {Debra C. Peters and Betancourt, J.L.} } @article {51093, title = {Changes in grassland canopy structure across a precipitation gradient}, journal = {Journal of Vegetation Science}, volume = {11}, year = {2000}, month = {June 1, 2000}, pages = {359-368}, abstract = {
In temperate grasslands, the relative importance of above ground competition for light compared to below ground competition for water and nutrients is hypothesized to increase with increasing precipitation. Thus, competition for light is likely to exert an increasing influence on canopy structure and species composition as precipitation increases. We quantified canopy structure, light availability and changes in species composition at seven sites across the central grassland region of the United States to determine how these properties change across a precipitation gradient. Across the region, there was a disproportionate increase in leaf area and canopy height with increasing precipitation, indicating that plants become taller and leafier across the gradient. Leaf area index increased by a factor of 12 across the gradient while above-ground net primary productivity increased by a factor of only 5.5. As precipitation increased, there was decreased light availability at the soil surface, increased seasonal variability in light transmission, increased biomass and leaf area at higher canopy layers and an increased proportion of tall statured species. These observed changes in canopy structure support the prediction that competition for light increases in importance with increasing precipitation.
}, keywords = {canopy structure, ecological processes, grassland, precipitation gradient}, doi = {10.2307/3236628}, url = {/files/bibliography/00-009.pdf}, author = {D. R. Lane and Debra C. Peters and W. K. Lauenroth} } @article {51103, title = {Climatic variation and simulated patterns in seedling establishment of two dominant grasses at a semi-arid and grassland ecotone}, journal = {Journal of Vegetation Science}, volume = {11}, number = {4}, year = {2000}, month = {August 1, 2000}, pages = {493-504}, abstract = {Seedling establishment by two congeneric C4 perennial grasses (Bouteloua gracilis and B. eriopoda) that dominate semiarid and arid North American grasslands was simulated by modeling multiple temporal frequencies of climate at their ecotonal boundary. The occurrence of a recruitment event in each year was determined by comparing simulated soil water content through time with amount and timing of soil water required for establishment based on data in the literature for each species. The two Bouteloua species had different regeneration strategies. B. gracilis had a broad pattern of establishment that occurred from June through October with a peak in September and October when year-to-year variation in precipitation was high. B. eriopoda had a narrow distribution of establishment events that peaked in the middle of summer (July) when precipitation amounts were most reliable. Interdecadal variation in climate had species-specific effects on establishment. Climatic condition from 1949 through 1968 were more favorable for B. eriopoda establishment compared to the cooler, wetter conditions from 1969 through 1988 that favored B. gracilis. Establishment of B. eriopoda was negatively affected by El Nino events, whereas B. gracilis establishment was positively affected by conditions associated with El Nino events. A long-term directional increase in annual precipitation resulted in a small shift in the geographic location of the ecotonal boundary based upon the location of similar establishment probabilities for the two species. These results indicate that temporal partitioning of soil water required by seedlings may account for species coexistence at an ecotonal boundary.}, keywords = {B. eriopoda, Bouteloua gracilis, ECOTONE, seedling establishment}, url = {/files/bibliography/00-016.pdf}, author = {Debra C. Peters} } @conference {51106, title = {Controls on patterns in species dominance across multiple spatial scales at a biome transition zone}, booktitle = {85th Annual Meeting, Ecological Society of America}, year = {2000}, month = {August 6-10, 200}, pages = {372}, address = {Snowbird, UT}, abstract = {Grassland landscapes at the SEV-LTER consist of a mosaic of patches of variable size and shape that are dominated or codominated by one of two Bouteloua species that characterize two other LTER sites. Bouteloua gracilis (blue grama) dominates shortgrass steppe ecosystems at the SGS-LTER in northern Colorado, and B. eriopoda (black grama) dominates Chihuahuan Desert grasslands at the JER-LTER in southern New Mexico. Our overall objective of this ongoing work is to examine controls on patterns in dominance by these species at the shortgrass steppe/Chihuahuan Desert biome transition zone in central New Mexico. A combination of field investigations, experiments, and simulation model analyses are being used to evaluate the key abiotic variables and biotic processes controlling these patterns. Broad-scale patterns in dominance are related to interactions between climate, topography, and soils. As the spatial scale decreases, the importance of patchily distributed disturbances to species dominance increases. Recruitment strategies and temporal partitioning of soil water are key processes determining dominance patterns under different environmental conditions. Predictions from simulation model analyses indicate that a trend toward hotter growing seasons or an increased frequency of disturbance will result in shifts in dominance to black grama, the Chihuahuan Desert species.}, keywords = {biome transition zone, grassland, patterns, SEV-LTER, spatial scales, species dominance}, author = {Debra C. Peters and J. R. Gosz} } @conference {51105, title = {Cross-site comparisons of climate and vegetation for two semiarid grasslands and their ECOTONE}, booktitle = {85th Annual Meeting, Ecological Society of America}, year = {2000}, month = {August 6-10, 200}, pages = {372}, address = {Snowbird, UT}, abstract = {The objective of this ongoing work is to compare ecosystem characteristics of three LTER grassland sites located along a north-south aridity gradient. These sites share some characteristics and differ in others that are expected to be important to their ability to respond to environmental drivers, including climate change and land use. The SGS-LTER in northern Colorado is representative of the shortgrass steppe and is dominated by th long-lived bunchgrass, Bouteloua gracilis (blue grama). Grasslands at the JER-LTER in southern New Mexico are dominated by the short-lived stoloniferous grass, Bouteloua eriopoda (black grama). Landscapes at the SEV-LTER in central New Mexico consist of patches that are dominated or codominated by these two species. Regional analyses of the climate and simulated recruitment showed important differences between biomes that may account, at least in part, for observed patterns in dominance and species diversity. Field studies of seed production and seed storage in the soil, as well as simulation analyses, showed the responses of these species at their ecotone are not predictable based on responses within the biomes where they dominate.}, keywords = {characteristics, ecosystem, grassland, LTER}, author = {Debra C. Peters} } @inbook {51132, title = {The Chihuahuan Desert Ecosystem}, booktitle = {Ensuring Sustainable Development of Arid Lands Through Time}, volume = {39}, year = {1999}, month = {1999}, pages = {45-85}, publisher = {New Mexico Journal of Science}, organization = {New Mexico Journal of Science}, abstract = {The Chihuahuan Desert is the least known of all the deserts in North America. It is the largest of the deserts and lies east of the continental divide between two mountain ranges in Mexico, Sierra Madre Occidental on the west and Sierra Madre Oriental on the east. On the south it borders mountains in Zacatecas and San Luis Potosi and to the north it opens onto broad valleys, basins, and high plains in New Mexico and west Texas. Because of its high elevation, averaging 1400 m above sea level, it is cooler than the other hot deserts in North America. Average precipitation is 235 mm/year and annual average temperature is over 18 deg C. Freezing temperatures in winter characterize the northern part of the desert, but are infrequent in the central and southern regions. A great variety of animals and plants live in the desert and characterize the wide variety of habitats resulting from the physiographic and climatic conditions found there. Much of the vegetation is characterized by desert scrub with grasslands and woodlands in more mesic areas, usually in uplands associated with the small mountains that dot the landscape. Large numbers of people live in and near the Chihuahuan Desert. As the human population continues to expand, more and more demands will be placed upon the limited resources of the Chihuahuan Desert. In this chapter we hope to present the wide variety of life and conditions that make the Chihuahuan Desert.}, url = {/files/bibliography/558.pdf}, author = {Reldon F. Beck and Gibbens, Robert P.}, editor = {Herrera, E.A. and Mexal, J.} } @article {JRN54594, title = {Comparison of Precipitation Catch Between Nine Measuring Systems}, journal = {Journal of Hydrologic Engineering}, year = {1999}, month = {01/1999}, type = {Journal articale}, chapter = {70}, abstract = {

A site was established by the U.S.. Department of Agriculture-Agricultural Research Service on the Reynolds Creek Experimental Watershed in southwest Idaho in the fall of 1987 and operated through the spring of 1994, to compare precipitation catch between nine precipitation-measuring systems. This site was established as a part of the World Meteor logical Organization{\textquoteright}s program to compare current national methods of measuring solid precipitation (snow), so the primary emphasis of this study was the measurement of snowfall. Over seven seasons, four of the systems measured snowfall and total catch, which included snow, mixed snow and rain, and rain events, with in 4\% of the Wyoming shielded gauge, which had the greatest total catch. These measuring systems were the Alter shielded gauge and the dual-gauge system from the United States, the double-fence shielded gauge from Russia, and the Nipher shielded gauge from Canada. the Unshielded universal recording gauge that was mounted with its orifice at 3.05 m had the least catch in all precipitation categories, which amounted to 24\% less snow, 18\% less mixed snow and rain, and 10\% less rain than was measured by the Wyoming shielded gauge.

}, author = {Hanson, Clayton L. and G. Johnson and A. Rango} } @article {51168, title = {Controls of sediment transport capacity in laminar interrill flow on stone-covered surfaces}, journal = {Water Resources Research}, volume = {35}, year = {1999}, note = {//?//LTER III//}, month = {1999}, pages = {305-310}, abstract = {

Sediment transport capacity is an important control on soil erosion and deposition by overland flow. To investigate the controls of transport capacity in laminar interrill overland flow on stone-covered surfaces, 357 flume experiments were performed using a single sediment size. Multiple regression analyses reveal that transport capacity is positively related to excess flow power ω - ωc, but the slope of the relation is steeper where ω \< 0.3 W m-2 than where ω >= 0.3 W m-2. Transport capacity is positively related to rainfall intensity where ω \< 0.3 W m-2 and negatively related to rainfall intensity where ω >= 0.3 W m-2. Transport capacity is negatively related to stone concentration and positively related to stone size irrespective of the value of ω. Finally, transport capacity is negatively related to fluid viscosity where ω \< 0.3 W m-2 and unrelated to viscosity where ω >= 0.3 W m-2.

}, keywords = {article, articles, hydrology, rills, hydrology, sediment transport, journal, journals}, doi = {10.1029/98WR02534}, url = {files/bibliography/JRN00271.pdf}, author = {Gary Li and Athol D. Abrahams} } @article {51194, title = {Controls on soil biodiversity: insights from extreme environments}, journal = {Applied Soil Ecology}, volume = {13}, year = {1999}, note = {//NMSU,USDA//LTER III//}, month = {1999}, pages = {137-150}, abstract = {

Research in low biodiversity extreme environments allows separation of the climatic, soil and biological interactions that determine soil biodiversity and community structure. Studies focused on the response of low diversity communities in soils of the Antarctic Dry Valleys and the Chihuahuan Desert of the southwestern USA, to manipulations of soil resources and climate, offer the best opportunity to learn about the environmental controls on soil biodiversity and the role of biodiversity in soil functioning. We propose that insights based on research in these extreme environments should be applicable to understanding soil biodiversity in more complex, temperate and tropical ecosystems. The study of extreme soil ecosystems may also provide information on the response of soil biodiversity to increasing occurrences of environmental extremes that are predicted to occur from global change models. Studies from hot and cold deserts show that decomposition-based food webs can be very simple, that aridity produces similar mechanisms for survival and dispersal of organisms in temperate and polar systems, that suitable soil habitats are patchily distributed in arid environments, and the low biodiversity of extreme soil ecosystems creates little or no functional redundancy making these systems susceptible to disturbance. We suggest that species within the same functional group can have small differences in ecology that are sufficient to affect ecosystem processes. When this occurs, differential responses of species to disturbance within a functional group will not stabilize the soil ecosystem, but rather lead to dramatic changes in community composition and ecosystem process rates.

}, keywords = {article, articles, disturbance, ecosystem, ecosystem function, journal, journals, nematode, species richness, survival}, doi = {10.1016/S0929-1393(99)00029-3}, url = {files/bibliography/JRN00272.pdf}, author = {D.H. Wall and R. A. Virginia} } @conference {51215, title = {Concentrations and distributions of nordihydroguaiaretic acid, total phenolics and condensed tannins in creosotebush (Larrea tridentata)}, booktitle = {Annual Meeting, Society for Range Management}, volume = {51}, year = {1998}, month = {1998}, pages = {29}, abstract = {Creosotebush contains a variety of secondary metabolites that have important ecological roles. Some, such as nordihydroguaiaretic acid (NDGA), have been proposed to have allelopathic effects that may contribute to the rapid expansion of creosotebush. Studies suggest phenolic compounds in roots affect root longevity, soil microbial processes and may have allelopathic properties. While NDGA concentrations in the above ground fraction has been extensively studied, other phenolic compounds throughout the plant, including the roots, have received little attention. Five creosotebush plants were collected and divided into 9 tissue categories. These categories were then analyzed for concentrations of NDGA, total phenolics and condensed tannins. NDGA was confined to "green" tissues such as leaves, flowers and stem tips. Total phenolics were found in all tissues with leaves, green stems and roots containing the highest concentrations. Condensed tannins were found in relatively low concentrations throughout all tissues except for seeds, which had levels roughly 17 times the mean concentration found in the rest of the plant. Future studies will look at the role of phenolics in modifying the plants immediate environment including allelopathic effects on sympatric plant species.}, author = {E.L. Fredrickson and P.W. Hyder and M.R. Tellez and Richard E. Estell} } @proceedings {51228, title = {Coexistence pattern in respect to the dominant species in a desert grassland-shrubland ecotone: from the individual plant to the landscape level}, year = {1998}, month = {March 17-21, 199}, address = {East Lansing, MI}, url = {/files/bibliography/565.pdf}, author = {Hochstrasser, T. and D.P. Coffin} } @conference {51229, title = {Computerized technique for the assessment of plant utilization by herbivores}, booktitle = {Society for Range Management Meeting}, volume = {51}, year = {1998}, month = {1998}, pages = {Abstract 34}, abstract = {A digital-photographic method was developed to determine degree of plant herbivores. Forty alfalfa plants were used to develop predictive regressions was photographed from two angles, 0 and 90, for baseline values of area. Samples approximating volumes typical of sheep bites were then removed from each plant. After each sample was removed the plant was again photographed from both angles. This was repeated until the entire aboveground portion of the plant was removed. Two methods were used for sampling; (1) removing leaves and stems simultaneously, (2) removing leaves only. The resulting photographs were digitized and loaded into a graphics program that allowed pixel area to be determined. A random coefficient model was used to calculate the relationship between sample mass and pixel area. Analyses were performed on 0{\textdegree}, 90{\textdegree} and both angles combined. The combination of the two proved to be the best predictor of mass removal. The confidence interval widened as the proportion of material removed increased. Although accuracy and precision was appropriate for some applications, several planned modifications should increase accuracy and ease of the method.}, author = {P.W. Hyder and E.L. Fredrickson and Richard E. Estell and Kris Havstad and M.D. Remmenga} } @proceedings {51230, title = {Comparative study of grasslands along aridity gradients}, year = {1998}, month = {July 19-25, 1998}, pages = {236}, address = {Florence, Italy}, abstract = {

The goal of this US-Hungarian collaborative work is to evaluate the importance of environmental constraints to the structure of arid and semiarid grasslands. For analyzing biodiversity, we use techniques based upon information statistics developed by Hungarian ecologists, while simulation models developed by U.S. ecologists are used to evaluate short- and long-term responses of vegetation to current and expected climatic conditions. Changes of diversity and spatial patterns of vegetation were studied along aridity gradients in both countries across a range of scales from 0.05m to 50m. In both cases, the diversity of species combinations and the strength of spatial associations decreased and the characteristic scale of maximum diversity of species combinations increased with increasing aridity. The spatial variation of estimated characteristics was higher at the arid end of the gradients.

}, author = {Kovacs-Lang, E. and Bartha, S. and Kertsz, M. and G. Kroel-Dulay and Hahn, I. and Redei, T. and Molnar, E. and Odor, P. and Hochstrasser, T. and Debra C. Peters} } @conference {51237, title = {Changes in grassland canopy structure across a productivity gradient}, booktitle = {83rd Annual Meeting, Bulletin of the Ecological Society of America}, volume = {79}, year = {1998}, month = {1998}, pages = {186}, abstract = {The canopy structure of a grassland community has important effects on ecological processes by influencing the availability of light for individual plants growing within the community. As productivity increases, belowground processes are predicted to decrease in relative importance for determining community structure while aboveground processes are predicted to increase. We quantified vertical profiles of light transmission, biomass, and leaf area for three natural grassland types in the Central Grassland region of the United States to examine how these properties varied with increased productivity. Overall, increased productivity across the study gradient was correlated with increased canopy height, decreased light availability at the soil surface, increased seasonal changes in light transmission, increased biomass and leaf area at higher canopy layers, and increased leaf area index. The changes in canopy structure that we documented support the prediction that aboveground processes related to capturing light increase in importance with increasing precipitation and productivity. These changes in canopy structure are likely to affect resource availability and successional dynamics across a productivity gradient.}, author = {D. R. Lane and D.P. Coffin and W. K. Lauenroth} } @article {51241, title = {Changes in mass and chemistry of plant roots during long-term decomposition on a Chihuahuan Desert watershed}, journal = {Biology and Fertility of Soils}, volume = {26}, year = {1998}, month = {1998}, pages = {16-22}, abstract = {

We studied the spatial and temporal patterns of decomposition of roots of a desert sub-shrub, a herbaceous annual, and four species of perennial grasses at several locations on nitrogen fertilized and unfertilized transects on a Chihuahuan Desert watershed for 3.5 years. There were few significant differences between the decomposition rates of roots on the NH4NO3 fertilized and unfertilized transects. Decomposition of all roots followed a two-phase pattern: early rapid mass loss followed by a long period of low mass loss. Rates of decomposition were negatively correlated with the initial lignin content of the roots (r=0.90). Mass loss rates of the roots of the herbaceous annual, Baileya multiradiata, were significantly higher than those of the grasses and the shrub, probably as a result of subterranean termites feeding on B. multiradiata root material. The only location where mass loss rates were significantly different was the dry lake bed, where mass loss rates were lower than those recorded on the upper watershed. The spatial differences in mass loss rates in the dry lake were attributable to the high clay content of the soils, which reduced water availability, and to the absence of termites. Non-polar substances in decomposing roots decreased rapidly during the first year, then decreased at a low but fairly constant rate. Water-soluble compounds decreased rapidly (50{\textendash}60\% of initial concentration) during the first 3{\textendash}6 months. Lignin concentrations of roots of perennial grasses were higher than those of herbaceous annual plants and woody shrubs. Lignin concentrations increased in all species during decomposition. The chemical changes in decomposing roots followed the patterns described for decomposing litter in mesic environments.

}, keywords = {Chihuahuan Desert, decomposition, Lignin, Mass loss, nitrogen immobilization}, doi = {10.1007/s003740050336}, url = {/files/bibliography/629.pdf}, author = {Hyeong-Tae Mun and Walter G. Whitford} } @article {51250, title = {Comparison of root distributions of species in North American grasslands using GIS}, journal = {Journal of Vegetation Science}, volume = {8}, year = {1998}, month = {1998}, pages = {587-596}, author = {Sun, G. and Coffin, E.P. and W. K. Lauenroth} } @article {51251, title = {Comparison of field methods to detect termite activity in the northern Chihuahuan Desert (Isoptera)}, journal = {Sociobiology}, volume = {32}, year = {1998}, month = {1998}, pages = {1-15}, abstract = {

The subterranean termites, Gnathamitermes tubiformans (Buckley) and Amitermes wheeleri (Desneux), play an essential role in terrestrial ecosystems of the northern Chihuahuan Desert. They regulate nutrient turnover, contribute to patterns of nutrient concentration, and determine the diversity and heterogeneity of desert plant communities. Therefore, they are considered keystone species in northern Chihuahuan Desert ecosystems. Our objectives were to compare the efficiency and cost effectiveness of six field procedures to detect termite activity. Efficiency was defined as the relative ability to attract termites during a given period of time. Cost effectiveness was based on the number of hours involved in preparing, handling and processing the samples. The methods included artificial baits, natural baits, and litter sweeps. The specific baits were: uncoated corrugated cardboard blocks, unscented generic rolls of toilet paper, cattle dung, fluff grass (Dasyochloa pulchella), and soap-tree yucca (Yucca elata) stalks. In addition, termites were collected with litter sweeps. Results show that cattle dung is the most efficient in detecting termite activity, and litter sweeps the most cost effective, although also least efficient. The results of this study will benefit future termite studies on consumption rates, and relative population densities.

}, url = {/files/bibliography/635.pdf}, author = {H. S. Taylor and William P. MacKay and Jeffrey E. Herrick and Guerrero, R.A. and Walter G. Whitford} } @article {51258, title = {Contribution of pits dug by goannas (Varanus gouldii) to the dynamics of banded mulga landscapes in eastern Australia}, journal = {Journal of Arid Environments}, volume = {40}, number = {4}, year = {1998}, month = {December 1, 1998}, pages = {453-457}, abstract = {

The densities of pits made by goannas Varanus gouldii were estimated in the three distinct zones of banded mulga landscapes (erosion slope, interception zone, and mulga grove) in paddocks of a grazing study in northwestern New South Wales, Australia. In lightly and moderately grazed paddocks, soil pits were significantly more abundant in the interception zones (M = 119{\textbullet}7m to the -2 degree) than in the groves and erosion slopes (M = 16{\textbullet}m to the -2 degree). In the overgrazed paddock, there were no differences in densities of pits in any of the zones. In the groves and erosion slopes, approximately 70-80\% of the pits contained litter, seeds, and fruits. However, on the erosion slopes, less than 20\% of the pits contained litter and seeds. The data support the hypothesis that soil disturbance by Varanus lizards produces a positive feedback mechanism for the viability of the interception zone and the functioning of banded vegetation landscapes.

}, keywords = {Australia, banded vegetation, goannas, grazing, landscapes, lizard, pits, seeds}, doi = {10.1006/jare.1998.0464}, url = {/files/bibliography/645.pdf}, author = {Walter G. Whitford} } @article {51270, title = {Carbon isotopes reveal soil organic matter dynamics following arid land shrub expansion}, journal = {Oecologia}, volume = {110}, year = {1997}, note = {//USDA//LTER III//}, month = {1997}, pages = {374-386}, abstract = {

Over the past century, overgrazing and drought in New Mexico{\textquoteright}s Jornada Basin has promoted the replacement of native black grama (Bouteloua eriopoda Torr.) grass communities by shrubs, primarily mesquite (Prosopis glandulosa Torr.). We investigated the effects of shrub expansion on the distribution, origin, turnover, and quality of light (LFC) and heavy (HFC) soil organic matter (SOM) fractions using δ13C natural abundance to partition SOM into C4 (grass) and C3 (shrub) sources. Soil organic matter beneath grasses and mesquite was isotopically distinct from associated plant litter, providing evidence of both recent shrub expansion and Holocene plant community changes. Our δ13C analyses indicated that SOM derived from mesquite was greatest beneath shrub canopies, but extended at least 3 m beyond canopy margins, similar to the distribution of fine roots. Specific 14C activities of LFC indicated that root litter is an important source of SOM at depth. Comparison of turnover rates for surface LFC pools in grass (7 or 40 years) and mesquite (11 or 28 years) soils and for HFC pools by soil depth (\~{}150{\textendash}280 years), suggest that mesquite may enhance soil C storage relative to grasses. We conclude that the replacement of semiarid grasslands by woody shrubs will effect changes in root biomass, litter production, and SOM cycling that influence nutrient availability and long-term soil C sequestration at the ecosystem level.

}, keywords = {article, articles, carbon dynamics, decomposition, carbon isotope ratios, carbon storage, soil, journal, journals, shrub encroachment, Prosopis, shrub, Prosopis, soil, organic carbon}, url = {files/bibliography/JRN00232.pdf}, author = {S. L. Connin and R. A. Virginia and Chamberlin, C. P.} } @conference {51279, title = {Coupling use-dependent and use-invariant data for simplified soil quality evaluation}, booktitle = {Annual Meeting, American Society of Agronomy}, year = {1997}, month = {October 26-31, 1}, pages = {Abstract 252}, address = {Anaheim, CA}, abstract = {The interpretive data base of the National Cooperative Soil Survey is largely use-invariant. The same data record applies irrespective of the present soil use. Soil quality requires a use-dependent data base and, commonly, point observations within components of map units. We present examples of point observations for the near surface combined with the use-invariant interpretive data base. The latter is applied below the depth of physical change caused by human activities or to properties at a shallower depth that are not affected by use. Both the use-dependent and the use-invariant properties are placed in quality classes. The class placements are integrated to form an overall quality assessment.}, author = {R. Grossman and D. E. Harms and Seybold, R.A. and Pytlik, L.A. and Jeffrey E. Herrick} } @conference {51283, title = {Contribution of soil termite activity to remediation of degraded rangeland}, booktitle = {Annual Meeting, American Society for Agronomy}, year = {1997}, month = {October 26-31, 1}, pages = {294-295}, address = {Anaheim, CA}, abstract = {The hypothesis that termite activity could be used to enhance infiltration capacity in degraded rangelands was tested at the Jomada Experimental Range by measuring infiltration rates at a variety of tensions beneath organic (cattle dung patches) and artificial (styrofoam) baits placed in highly impacted areas on two soils. There was no treatment effect on near-equilibrium infiltration rates into tlr.{\textquoteright} sandy loam under 120mm and 40mm of tension (approximate pore equivalent).}, author = {Jeffrey E. Herrick and Walter G. Whitford and Jones, T.L.} } @conference {51288, title = {Concepts and real issues of desertification and remediation in the Mediterranean and the southwestern United States: transcending local values through a focus on ecological functions}, booktitle = {International Symposium and Workshop Combating Desertification: Connecting Science with Community Action}, year = {1997}, month = {May 12-16, 1997}, pages = {Abstract 11}, address = {Tucson, AZ}, abstract = {Desertification is perceived to be a major problem in both the area surrounding the Mediterranean basin and in the southwest United States. A consensus exists in both regions that these regions are experiencing severe physical and biological land and socioeconomic degradation. There is also a consensus, arrived at during recent symposia (Tucson, October 1994), that the underlying causes and processes are similar. In attempting to further understand the similarities by comparing research results from field studies, however, it became clear that perceptions of desertification in these two regions are based on two completely different concepts. In Europe, there is the classic idea that the dry Mediterranean regions were once extensively forested and that a combination of grazing, fire, and cultivation have through history led to a loss of forests. In response, policy is often directed at restoring forest and woody vegetation irrespective of climate or the impact of restoration on key ecosystem functions. Grassland vegetation is seldom perceived as a potential and desirable objective. In the southwest U.S., by contrast, the loss of the desert grass ecosystem and invasion of woody species are regarded as signs of desertification. Consequently, U.S. policy is directed at reversing the development of ecosystems that in Europe are considered desirable. To develop appropriate remediation approaches, we need to clearly define the objectives and criteria to be used to assess the remediation. We believe that these criteria must be developed independently of preconceived notions of an "ideal" or "historic" vegetative community. Rather, these criteria should be based on the relative capacity of the current system to perform specific functions. These functions fall into two closely related categories: (1) functions that make the system sustainable, and (2) functions that provide a specific use-value for the broadly defined needs of human society. In desertified systems the first set of functions may be defined more specifically as those that contribute to the capacity of the system to retain soil and water and therefore to continue to support biological production. As such, they are relatively independent of specific human values. The second set of functions are germane only after the criteria for the first set of functions are satisfied. The second set may include a wide variety of value-related services that these systems provide, including production of food and fiber, conservation of biological species and/or communities, water management, carbon storage, and recreation opportunities.}, author = {Imeson, A.C. and Kris Havstad and Jeffrey E. Herrick} } @article {51289, title = {A comparative study of soil water dynamics in a desert ecosystem.}, journal = {Water Resources Research}, volume = {33}, year = {1997}, note = {//??//LTER III//}, month = {1997}, pages = {73-90}, abstract = {

We compared three different soil water models to evaluate the extent to which variation in plant growth form and cover and soil texture along a topographic gradient interact to affect relative rates of evaporation and transpiration under semiarid conditions. The models all incorporated one-dimensional distribution of water in the soil and had separate functions for loss of water through transpiration and soil evaporation but differed in the degree of mechanism and emphasis. PALS-SW (Patch Arid Lands Simulator-Soil Water) is a mechanistic model that includes soil water fluxes and emphasizes the physiological control of water loss by different plant life forms along the gradient. 2DSOIL is a mechanistic model that emphasizes the physical aspects of soil water fluxes. SWB (Soil Water Budget) is a simple water budget model that has no soil water redistribution and includes simplified schemes for soil evaporation and transpiration by different life forms. The model predictions were compared to observed soil water distributions at five positions along the gradient. All models predicted soil water distributions reasonably well and, for the most part, predicted similar trends along the transect in the fractions of water lost as soil evaporation versus transpiration. Transpiration was lowest (about 40\% of total evapotranspiration (ET)) for the creosote bush community, which had the lowest plant cover (30\% peak cover). The fraction of ET as transpiration increased with increasing plant cover, with 2DSOIL predicting the highest transpiration (60\% of total ET) for the mixed vegetation community (60\% peak cover) on relatively fine textured soil and PALSr SW predicting highest transpiration (69\% of total ET) for the mixed vegetation community (70\% peak cover) on relatively coarse textured soil. The community type had an effect on the amount of water lost as transpiration primarily via depth and distribution of roots. In this respect, PALS-SW predicted greatest differences among stations as related to differences in plant community types. However, since PALS-SW did not provide as good of fit with the soil moisture data as did 2DSOIL, the differences in the morphology and physiology of the life-forms may be secondary to the overall control of water loss by the primary factors accounted for in 2DSOIL: vertical distribution of soil moisture, degree of canopy cover, and evaporative energy budget of the canopy. Soil texture interacted with the amount and type of plant cover to affect evaporation and transpiration, but the effect was relatively minor.

}, keywords = {article, articles, journal, journals, soil, water dynamics, water dynamics, soil}, doi = {10.1029/96WR03015}, url = {files/bibliography/JRN00228.pdf}, author = {P. R. Kemp and J. F. Reynolds and Y. Pachepsky and J. Chen} } @conference {51301, title = {Canopy insect populations as indicators of exposure to acute stressors (drought and grazing) and chronic stressors (desertification and exotic plant species)}, booktitle = {International Symposium and Workshop Combating Desertification: Connecting Science with Community Action}, year = {1997}, month = {May 12-16, 1997}, pages = {Abstract 22}, address = {Tucson, AZ}, url = {/files/bibliography/596.pdf}, author = {W. E. Smith and Justin Van Zee and Walter G. Whitford} } @conference {51307, title = {Classification, ecological risk, and decision: assessing desertification in south-central New Mexico}, booktitle = {International Symposium and Workshop Combating Desertification: Connecting Science with Community Action}, year = {1997}, month = {May 12-16, 1997}, pages = {Abstract 44}, address = {Tucson, AZ}, abstract = {

Classification of remotely sensed and ground-based data is at the heart of landscape monitoring, calculating ecological risk, and decision making. The simplest classification may be a binary decision: the land is either degraded or it is not. This research investigates several problems that arise because of the subjective nature of that final decision and suggests a process for minimizing the least-desirable errors. We use a combination of field vegetation surveys, classified remotely sensed AVHRR images, and error analysis to answer questions about the impact of classification error on management decisions. We use our data to estimate (1) the probability that the classification of an arbitrary pixel is incorrect, (2) the rates of different types of mis-classification (Type I vs. Type II statistical errors), and (3) the implication of such errors for management and risk analysis. Although our study focuses on south-central New Mexico (USA), we expect the approach will be broadly applicable and have implications for other arid regions.

}, author = {S.J. Turner and A. R. Johnson and A.G. de Soyza and Justin Van Zee and M.D. Eve and Walter G. Whitford} } @article {51324, title = {Chemical composition of Flourensia cernua at four growth stages}, journal = {Grass and Forage Science}, volume = {51}, year = {1996}, month = {1996}, pages = {434-441}, abstract = {

Tarbush (Flourensia cernua DC) is an abundant Chihuahuan Desert shrub but is used sparingly by livestock. Leaves were removed from forty tarbush plants harvested in each of 3 years during four growth stages: (1) early, (2) mid-point, (3) late and (4) curtailed growth (ten plants per growth stage each year). Plants were air dried and all leaves were removed. In vitro dry-matter (DM) disappearance was greater for the early growth stage than other stages (P\<{\textperiodcentered}05). The fibrous fraction increased with maturity, with neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) contents all less for the early growth stage (P\<0-05) than other stages. The latter three growth stages did not differ in NDF or ADF content, but ADL content was lower for the mid-point growth stage than for the two later stages (P\<{\textperiodcentered}05). Calcium content increased with advancing season (P\<0-05), whereas phosphorus concentration exhibited an inverse pattern (P\<{\textperiodcentered}05). Nitrogen (N) content of tarbush was greatest in the early growth stage (P-cO-OS) and declined substantially thereafter. Soluble N content was greater and acid detergent insoluble N (ADIN) content was lower for early growth (P\<{\textperiodcentered}05) than other stages. Insoluble N concentration followed a pattern similar to N, declining with advancing season (P{\textperiodcentered}Q5). When expressed as a fraction of total N, insoluble N decreased and soluble N increased with maturity (P\<{\textperiodcentered}05). Condensed tannin concentration tended (P\<{\textperiodcentered}10) to increase with advancing season. Total phenolic content was lowest for early growth (P \<{\textperiodcentered}05), and did not differ among the other stages. Chemical analysis revealed tarbush to be relatively high in N concentration. Fibre fractions, ADIN, ADL and condensed tannins were all generally low whereas total phenolic content of tarbush was quite high. Early use by livestock would be most advantageous in terms of nutrient availability (N, P and in vitro digestibility) and lowest total phenolic concentration. Year-to-year variability in chemical composition of tarbush appears to be substantial. It remains to be seen whether overriding intake deterrents would be beneficial to livestock, given the high phenolic concentration in tarbush. Tarbush has several characteristics that make it a suitable model for studying plant-animal interactions of desert shrubs.

}, doi = {10.1111/j.1365-2494.1996.tb02078.x}, url = {/files/bibliography/475.pdf}, author = {Richard E. Estell and E.L. Fredrickson and Kris Havstad} } @proceedings {51358, title = {Condition of New Mexico rangelands derived from multi-year AVHRR imagery and associated spatial variables}, year = {1996}, month = {1996}, pages = {I-247 to I-256}, address = {Las Vegas, NV}, abstract = {The Desert Research Institute in cooperation with the Environmental Protection Agency Characterization Research Division, Las Vegas, has been evaluating indicators of rangeland health derived from remote sensing technology. The primary objective of this project was to determine the ability of multi-date remote sensing imagery to detect variation in vegetation productivity, as a potential indicator of ecosystem condition in the western U.S. The conterminous U.S. AVHRR biweekly composites were acquired from EROS Data Center from the six year 1989-1994. Normalized Difference Vegetaqtion Index (NDVI) data for New Mexico were imported into a Geographical Information System. Using a digital vegetation map for the state, woodland and montane vegetation types were masked, leaving two grassland and four shrub-dominated vegetation classes. Average annual NDVI was calculated for each year, and a series of regression analysis were performed using 1989 as the reference year (independent variable), and each subsequent year as dependent variables. Outliers were identified as pixels two standard deviations from the calculated regression line, indicating 14 areas of change, three with lower productivity versus 1989, and 11 with higher productivity. Mining, military activity and irrigated agriculture were among the causes of change.}, keywords = {AVHRR, imagery, New Mexico, rangelands, spatial variables}, author = {J. Lancaster and T. Wade and T. Minor and Walter G. Whitford and B. Jones} } @mastersthesis {51360, title = {Changes in soil labile-C indicated by the ratio of microbial biomass-C to total Organic-C in a semi-arid grassland undergoing desertification}, year = {1996}, note = {//NMSU//NONE, LTER//}, month = {1996}, pages = {108}, school = {University of Nevada}, type = {M.S. Thesispp}, address = {Reno, Nevada}, abstract = {To study changes in labile-C in a Chihuahuan desert grassland in southern New Mexico, microbial biomass-C (Cmic) and total soil organic-C (Corg) were measured along a gradient of long-term grazing impacts, with an ungrazed site chosen to represent steady state conditions with respect to soil organic matter. The results of this study show that the Cmic and Corg ratio is a better indicator of soil labile-C in this semi-arid ecosystem than either variable alone, and that different areas of the soil landscape have responded to grazing impacts in different ways. The Cmic and Corg ratio may thus provide a tool for monitoring changes in soil productivity that occur with desertification.}, keywords = {carbon,soil, desertification, organic carbon, dissertation, dissertations, microbial biomass, grassland, soil, labile carbon, soil, microbial biomss, soil, organic carbon, soil, organic matter turnover, theses, thesis}, author = {Lassetter, W.L.} } @article {51364, title = {Clay mineralogy at the Desert Project and the Rincon surface study area}, year = {1996}, note = {//LOCAL//LTER III//ProCite field[12]: In File (01/10/2005)}, month = {1996}, pages = {155}, institution = {USDA Natural Resources Conservation Service}, type = {pp}, address = {National Soil Survey Center, Lincoln, NE}, abstract = {

Volume II of the Supplement to the Desert Project Soil Monograph is the second of a number of reports on soils in the Desert Project area. Volume II consists of two chapters, of which the first is a detailed study of a remnant of the Rincon surface and its soils. The Rincon surface is a remnant of one of the oldest basin landscapes in North America, and probably dates from late Pliocene time or earlier. The remnant consists of an ancient basin floor and an adjacent alluvial-fan piedmont, preserved in a bedrock-defended area 600 feet above the Rio Grande flood plain. Chapter 2 focuses on clay mineralogy of the Desert Project and the Rincon study area. It describes clay mineralogy as a function of age, parent material, and depth. It also compiles the narrative clay mineralogy information produced during the period from 1957 to 1972.

}, keywords = {book, books, chapter, chapters, landscape, soil, report, reports, Rincon, soil, clay mineralogy, soil, Desert Project, soil, landscape evolution}, isbn = {Soil Survey Investigations Report $\#$44}, url = {files/bibliography/JRN00206.pdf}, author = {Curtis H. Monger and Lynn, W. C.}, editor = {L. H. Gile and R. J. eds. Ahrens} } @conference {51399, title = {Contribution of ant activity to spatial variability in hydrologic properties in the Chihuahuan Desert}, booktitle = {American Society of Agronomy Meeting}, year = {1995}, month = {October 29-Novem}, pages = {Abstract 309}, abstract = {The activity of soil fauna is frequently cited as a factor contributing to the spatial variability of arid rangeland soils in the southwestern United States. However, few studies have correlated differences in soil physical properties with the activity of specific soil organisms. In order to quantify the contribution of ant activity to spatial variability in surface macroporosity, infiltration rates under ponding and under tension at the center and margins of harvester ant (Pogonomyrmexrugosus) nests were compared with rates in adjacent, nonvegetated control sites. Both saturated hydraulic conductivity and the difference between saturated and unsaturated conductivity were highest at the nest centers. These results illustrate the role of ants in the creation of macropores capable of conducting water under conditions of overland flow. The results will be discussed with respect to patterns and densities of ant nests in the Chihuahaun Desert.}, keywords = {ant activity, Chihuahuan Desert, hydrologic properties, macropores, spatial variability}, author = {Jeffrey E. Herrick and Walter G. Whitford} } @article {51424, title = {Cloning of nod gene regions from mesquite rhizobia and bradyrhizobia and nucleotide sequence of the nodD gene from mesquite rhizobia}, journal = {Applied and Environmental Microbiology}, volume = {61}, number = {9}, year = {1995}, note = {//OTHER//LTER III//}, month = {1995}, pages = {3422-3429}, abstract = {Nitrogen-fixing symbiosis between acteria and the tree legume mesquite (Prosopis glandulosa) is important for the maintenance of many desert ecosystems. Genes essential for nodulation and for extending the host range to mesquite were isolated from cosmid libraries of Rhizobium (mesquite) sp. strain HW17b and Bradyrhizobium (mesquite) sp. strain HW10h and were shown to be closely linked. All of the cosmid clones of rhizobia that extneded the host range of Rhizobium (Parasponia) sp. strain NGR234CS to mesquite also supported nodulatoin of a Sym- mesquite strain. The cosmid clones of bradyrhizobia that extended the host range of Rhizobium (Parasponia) sp. strain NGR234CS to mesquite were only able to confer nodulation ability in the Sym- mesquite strain if they also contained a nodD-hybridizing region. Subclones containing just the nodD genes of either genus did not extend the host range of Rhizobium (Parasponia) sp. to mesquite, indicating that the nodD gene is insufficient for mesquite nodulation. The nodD gene region is conserved among mesquite-nodulating rhizobia regardless of the soil depth from which they were collected, indicating descent from a common ancestor. In a tree of distance relationships. the NodD amino acid sequence from mesquite rhizobia clusters with homologs from symbionts that can infect both herbaceous and tree legumes, including Rhizobium tropici, Rhizobium leguminosarum bv. phaseoli, Rhizobium loti, and Bradyrhizobium japonicum.}, keywords = {article, articles, bradyrhizobia, genetics,bradyrhizobia, genetics,rhizobia, journal, journals, Prosopis,bradyrhizobia, Prosopis,rhizobia, rhizobia, root,Prosopis rhizobia, soil,bradyrhizobia, soil,rhizobia}, author = {P. M. Thomas and K. F. Golly and R. A. Virginia and Judith W. Zyskind} } @article {51566, title = {Creosotebush vegetation after 50 years of lagomorph exclusion}, journal = {Oecologia}, volume = {94}, year = {1993}, month = {1993}, pages = {210-217}, chapter = {210}, abstract = {

In 1939 an experiment was established on the Jornada Experimental Range to evaluate the effects of brush removal, rabbit exclusion, furrowing, and seeding in creosotebush. Sixteen plots (21.3 x 21.3 m) were established in four rows of four with a buffer zone of 7.6 m between plots. A barbed wire fence excluded cattle and poultry wire fencing excluded lagomorphs. The treatments were factorially applied at two levels, yielding a check plot, 4 single-factor plots, and 11 plots with varying degrees of interaction. In 1989 the plots were sampled for shrub canopy cover and grass basal area with randomly located, line-intercept transects. The noneffective furrowing and seedling treatments were excluded from analyses. Multivariate analysis of variance was conducted by plant groups (shrubs, subshrubs, and grasses) to determine the effect of shrub removal and lagomorph exclusion. Grass basal area was higher (P = 0.026) on cleared (4.8\%) than on noncleared plots (4.0\%). Grass basal area on lagomorph-excluded plots (4.3\%) was higher (P = 0.018) than on plots grazed by lagomorphs (3.7\%). Subshrub canopy cover was different (P = 0.029) on lagomorph-excluded and lagomorph-grazed plots with different species showing opposite responses. These results indicate that lagomorphs have a profound influence on the species composition of creosotebush vegetation.

}, keywords = {Black-tailed jackrabbit, Larrea tridentata, Parthenium incanum, Spike dropseed, Sporobulus contractus}, doi = {10.1007/BF00341319}, url = {/files/bibliography/404.pdf}, author = {Gibbens, Robert P. and Billheimer, D.D. and Kris Havstad and C.H. Herbel} } @article {51493, title = {Classification of paleosols}, journal = {Geological Society of America Bulletin}, volume = {105}, year = {1993}, note = {//LOCAL//NONE//}, month = {1993}, pages = {129-136}, abstract = {Despite increased interest in paleosols during the past decade, no satisfactory classification is in current use. Presented here is a largely descriptive classification system that utilizes those pedogenic features that have the highest perservation potential in the rock record. Emphasized in the classification are morphological and mineralogical features that are easily recognizable in the field and through the petrographic microscope. The classification is based on evaluation of the relative prominence in a plaeosol of six pedogenic features or processes: organic matter content, horizonation, redox conditions, in situ mineral alteration, illuviation of unsoluble minerals/compounds, and accumulation of soluable minerals. The most prominent of these six features/processes provides the key to classifying a paleosol into one of nine orders. Four of the order names are borrowed from Soil Taxonomy (Histosol, Spodosol, Oxisol, Vertisol), whereas the other five order names ore presented here for the first time (Calcisol, Gypsisol, Gleysol, Argillisol, Protosol). The orders may be preceded by one or more subordinate modifiers that describe other important features of the paleosol. The classification is relatively easy to apply to the rock record and should enhance communication and aid in the standardization of terminology.}, keywords = {article, articles, geomorphology, paleosols, journal, journals, paleosols, classification, soil, paleosols}, author = {Greg H. Mack and Calvin W. James and Curtis H. Monger} } @article {51496, title = {Changing carbon chemistry of buried creosote bush litter during decomposition in the northern Chihuahuan Desert}, journal = {The American Midland Naturalist}, volume = {130}, year = {1993}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1993}, pages = {83-89}, abstract = {

In a previous study, creosote bush (Larrea tridentata) fine litter that was buried 5 cm beneath the soil surface in the northern Chihuahuan Desert lost about 20\% of the original mass during the following three month summer-autumn period. A mathematical model was devised to elucidate the interactions between litter decay and decomposer microorganisms, using soil moisture and temperature as primary driving variables and litter quality as a controlling factor. Chemical analyses of the litter remaining at various stages of decay now provide additional insight to the decomposition process and another assessment of model behavior. As litter decayed, quantities of soluble and holocellulosic materials decreased by 41\% and 22\% (respectively), and acid-insolubles increased by 34\%. This is consistent with microbially mediated decay processes in which recalcitrant microbial products (e.g., cell wall materials) accumulate as total litter mass decreases. Simulation results were comparable to observed patterns of changing litter chemistry, corroborating a microbial based explanation for decay in desert soils that is very similar to decomposition processes in more mesic temperate ecosystems.

}, keywords = {article, articles, carbon chemistry, decomposition,litter, journal, journals, Larrea, carbon chemistry, Larrea, litter decompositionr, litter,Larrea decomposition, model, decomposition, Larrea, model, GENDEC}, doi = {10.2307/2426277 }, url = {files/bibliography/JRN00167.pdf}, author = {Daryl L. Moorhead and J. F. Reynolds} } @article {51517, title = {A computational study of episodic events and historical context in long-term ecological process: climate and grazing in the northern Chihuahuan Desert}, journal = {Coenoses}, volume = {7}, number = {1}, year = {1992}, note = {//NMSU,USDA//LTER II//Listed in LTER3 proposal as citing LTER2 support//spelling corrections to abstract on 6/11/2009}, month = {1992}, pages = {55-60}, abstract = {We examined recent climate data from the Mesilla Valley in southern New Mexico, USA. Monthly data for total precipitation, maximum and minimum temperatures, and mean annual temperatures were analyzed from the Jornada Experimental Range Headquarters station (July 1914-Dec 1984) and NMSU station (Jan 1892-Dec 1984). We examined data at monthly, seasonal, and annual intervals. Seasons were developed that corresponded to vegetation and animal phenologies from the study area. Our intent was to examine the hypothesis that changes in climate patterns over the past 100 years were the causal agent in the observed shift in vegetation of the Jornada Basin from perennial grasslands to shrublands. An alternate hypothesis was that this vegetation shift was caused by the introduction and effect of grazing by domestic livestock. We conducted statistical analyses that included descriptive and exploratory techniques, linear and quadratic regression, de-trended autocorrelation analyses, and Monte-Carlo simulation studies. There were no statistically significant trends in precipitation in 11 of 12 months, with only May showing a significant quadratic fit. There are no statistically significant linear or quadratic trends in seasonal or annual precipitation totals from either the Jornada headquarters or the NMSU stations. Significant autocorrelation terms were obtained for lag times of 2, 4, 16, and 17 years. Only lag 17 showed agreement between both the Jornada headquarters and the NMSU stations. Spatial variability was demonstrated between the Jornada and the NMSU stations for both precipitation and temperature. This is particularly so for the summer season, where the Jornada precipitation is quite different from that at the NMSU station. Simulation studies allowed the examination of probabilities of occurrence of segments of data that constituted climatic events in the sense of being of interest biologically. These analyses allowed us to examine such events in the context of the recent climate history of the valley. We were able to demonstrate any consistent statistical rationale for invoking climate as a causal mechanism in the observed vegetative change of the valley. An examination of the history of grazing by introduced livestock leads to acceptance of an alternate hypothesis that this vegetation shift was caused by grazing effects from introduced livestock. These analyses also demonstrate that the meteorological and environmental "context" within which ecological studies are conducted can have significant influence on the results obtained.}, keywords = {article, articles, cattle grazing, climate, temperature, climate, trends, desertification,climate, grassland,climate, journal, journals, livestock,also SEE , model,monte-carlo simulations, precipitation,effects on vegetation, shrub, increase of}, author = {W.H. Conley and Marsha R. Conley and Karl, Thomas R.} } @article {51523, title = {Carbon and nitrogen limitations of soil microbial biomass in desert ecosystems}, journal = {Biogeochemistry}, volume = {18}, year = {1992}, note = {//USDA//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1992}, pages = {1-17}, abstract = {

Microbial biomass nitrogen was measured in unamended (dry) and wetted soils in ten shrubland and grassland communities of the Chihuahuan desert, southern New Mexico, by the fumigation-extraction method. Microbial biomass-N in dry soils was undetectable. Average microbial biomass-N in wetted soils among all plant communities was 15.3 ug g-1 soil. Highest values were found in the communities with the lowest topographic positions, and the minimum values were detected in the spaces between shrubs. Microbial biomass was positively and significantly correlated to soil organic carbon and extractable nitrogen (NH4+ + NO3-). In a stepwise multiple regression, organic carbon and extractable nitrogen accounted for 40.9 and 5.6\%, respectively, of the variance in microbial biomass-N among the samples. Among communities, the soil microbial biomass was affected by the ration of carbon to extractable nitrogen. Our results suggest a succession in the control of microbial biomass from nitrogen to carbon when the ratio of carbon to nitrogen decreases during desertification.

}, keywords = {article, articles, biogeochemistry,carbon, biogeochemistry,nitrogen, biogeochemistry,nutrient immobilization, carbon,soil, grassland,microbial biomass, journal, journals, microbial biomass, nitrogen,soil, nutrient,soil, playa,microbial biomass, shrubland,microbial biomass, soil,nutrient immobilization}, url = {files/bibliography/JRN00154.pdf}, author = {Gallardo, Antonio and W. H. Schlesinger} } @proceedings {51526, title = {Conference Proceedings}, year = {1992}, note = { //OTHER//LTER II//}, month = {April 22-26, 199}, address = {W.K. Kellogg Biological Station, Michigan State University}, abstract = { This publication is the result of deliberations by 40 representatives from stations and laboratories of all sizes. Their object was to produce a usable decision-making tool for data management planning and implementation. It is hoped that their shared wisdom will benefit the researchers, administrators and data managers at all field stations and marine laboratories.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, data management, proceeding, proceedings}, author = {Gorentz, John B. (ed.)} } @article {51538, title = {Climatic Guide, Las Cruces, 1892-1991, 100 Years of Weather Records}, year = {1992}, note = {//LOCAL//NONE//}, month = {1992}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, abstract = {This report updates and expands several earlier NMSU AES publications regarding the climate of the Las Cruces area. Houghton (1972) first provided a concise and useful summary of the climate of Las Cruces. Malm and Houghton (1977) updated the earlier work, as did Kunkel, Malm, and Earl (1988). These publications, now out of print, were valuable for research and educational applications. This report updates and expands those earlier works.}, keywords = {book, books, chapter, chapters, climate guide, evaporation, history, climate, precipitation, relative humidity, report, reports, solar radiation, temperature, air, temperature, soil, wind}, isbn = {Research Report 682}, author = {Malm, Norman R.} } @article {51573, title = {Can multi-species grazing help protect stock from coyotes?}, journal = {National Wool Growers{\textquoteright} Magazine}, volume = {81}, number = {(3)}, year = {1991}, month = {1991}, pages = {32-33}, abstract = {

Stocking ranges or pastures with more than one animal species often \ contributes to a more uniform and complete use of the available while providing a higher net return to producer. Cattle prefer grass, sheep \ prefer forbs (weeds) and goats prefer browse (shrubs and trees).

}, url = {/files/bibliography/372.pdf}, author = {Clarence V. Hulet and D.M. Anderson} } @proceedings {51590, title = {Climate, environment and ecology}, year = {1991}, note = {//OTHER//NONE//ProCite field[6]: In}, month = {1991}, keywords = {abstract, abstracts, climate, conference, conference proceedings, conferences, ecology, environment, proceeding, proceedings}, author = {W. H. Schlesinger}, editor = {Jager, J. (ed.)} } @proceedings {51608, title = {Composition and digestia kinetics of diets selected by suckling range calves}, volume = {41}, year = {1990}, month = {1990}, pages = {264-267}, keywords = {composition, digestia kinetics, suckling range calves}, author = {Bryan, K.S. and Ansotegui, R.P. and J. Lacey and Marlow, C.B. and Kris Havstad} } @proceedings {51644, title = {A comparison of runoff and sediment yields from bare and vegetated plots using rainfall simulation}, year = {1990}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//ProCite field[6]: In}, month = {1990}, pages = {245-255}, publisher = {American Society of Civil Engineers}, abstract = {The overall effects of vegetative cover on runoff and sediment yields are well known. Many references to the qualitative and quantitative effects can be found throughout the natural science and engineering literature. What is lacking are studies which detail the effects of cover on specific hydrologic and hydraulic processes or their representative parameters so that the results may be used for simulation modeling. Data from 108 small plot rainfall simulator experiments on pinyon-juniper woodlands in Arizona and New Mexico were analyzed to determine quantifiable effects of cover on hydrologic and sediment yield parameters. Significant effects were identified and linear models were developed to quantify them. Other published techniques for rangelands were applied to the data with limited success.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, hydrology,rainfall simulation, hydrology,runoff, hydrology,runoff plots, hydrology,sediment yield, proceeding, proceedings, rainfall simulation,hydrology, runoff,SEE , sediment,SEE }, author = {Timothy J. Ward and Asce, M. and Krammes, J. Sam and S. M. Bolton and Asce, A. M.}, editor = {R. Riggins and B. Jones and Ranvir Singh and Rechard, Paul A. (eds.)} } @article {51648, title = {Cattle liveweight sampled on a continuous vs. intermittent basis}, journal = {Livestock Production Science}, volume = {23}, year = {1989}, note = {Reprinted with permission from Elsevier, Copyright {\textcopyright} 1989. (http://www.sciencedirect.com/science/journal/03016226)}, month = {1989}, pages = {117-135}, abstract = {

The liveweight of a free-ranging cow is constantly changing. If she is weighed automatically upon entering a corral before drinking water, a liveweight profile results which can be used to manage her individual performance. Using a manual procedure and weighing the same cow every 28 days also results in a liveweight profile. To determine how the amount of information contained in the 2 weighing procedures differed, the same cows of an experimental herd were weighed using both procedures. The resulting data referred to 1281 manual and some 40 000 automatic weighings, which were then classified into the phenological stage of the grazed plants and the physiological stage of the cow. By assuming that a cow is biologically the same within a 7-day period, and with as little as 1 weeks{\textquoteright} data, an 11\% change in a cow{\textquoteright}s liveweight can be detected 90\% of the time with only one additional automatic weighing. Real changes in liveweight as little as 5\% can be detected at the same rate if more than a single weighing is observed. Therefore, automatic weighing not only can be used to estimate the effects of past management practices, but also can be useful in making sound day-to-day livestock management decisions on individual animals.

}, doi = {10.1016/0301-6226(89)90010-9}, url = {/files/bibliography/341.pdf}, author = {D.M. Anderson and Weeks, D.L.} } @article {51657, title = {Containment of free-ranging goats using pulsed-radio-wave-activated shock collars}, journal = {Applied Animal Behavior Science}, volume = {23}, year = {1989}, note = {Reprinted with permission from Elsevier, Copyright {\textcopyright} 1989. (http://www.sciencedirect.com/science/journal/01681591)}, month = {1989}, pages = {165-171}, abstract = {

Goats (Caprahircus) are useful for brush and weed control. Their usefulness would be enhanced if their distribution on grazing land could be controlled without herders or permanent fencing. The feasibility of using electric shock collars to restrict the range of grazing goats was evaluated. Electric shock collars developed for canine control were tested as an alternative method for unattended containment. Shock collars effectively contained goats within the designated test area. Goats not wearing the shock collars remained close to the collared goats due to herd instinct and, thus, also remained within the test area. Preliminary results indicate that the non-visual fence may make it feasible to develop commercial weed-grazing goat herds restricted to weed infestations by electric collars.

}, doi = {10.1016/0168-1591(89)90016-6}, url = {/files/bibliography/700.pdf}, author = {Philip A. Fay and McElligott, V.T. and Kris Havstad} } @mastersthesis {51676, title = {A comparison of three different techniques for determining diet composition}, year = {1989}, note = {//??//NONE//}, month = {1989}, pages = {51}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, theses, thesis}, author = {Mofarreh, Mohammed Mogbel} } @article {51677, title = {The contribution of abiotic processes to buried litter decomposition in the northern Chihuahuan Desert}, journal = {Oecologia}, volume = {79}, year = {1989}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1989}, pages = {133-135}, abstract = {

Creosotebush (Larrea tridentata) fine litter was treated with either the general biocide HgCl2 and CuSO4 or water (controls) and buried 5 cm beneath the soil surface in the northern Chihuahuan Desert. The treated litter showed significantly less mass loss than controls during the three month summer-autumn field study; controls lost about 20\% of the original mass while treated litter lost less than 2\%. In addition, the total nitrogen content of the control litter increased from and initial concentrations of about 14.08 g kg-1 to 17.62 g kg-1 dry weight by the end of the study, while treated litter nitrogen content decreased to 13.30 g kg-1. Results suggest abiotic processes other than leaching have little effect on the decomposition of buried litter in this environment.

}, keywords = {abiotic processes,decomposition, article, articles, biocide, HgCl2 and CaSO4, biocide,also SEE , copper sulfate, decomposition, abiotic processes, decomposition, litter, journal, journals, Larrea,decomposition, litter,Larrea, mercuric chloride}, doi = {10.1007/BF00378250}, url = {files/bibliography/JRN00109.pdf}, author = {Daryl L. Moorhead and J. F. Reynolds} } @article {51688, title = {Carbon balance of Panicum coloratum during drought and non-drought in the northern Chihuahuan desert}, journal = {Journal of Ecology}, volume = {77}, year = {1989}, month = {1989}, pages = {799-810}, abstract = {

(1) The daily C02 flux of above-ground and below-ground components of Panicum coloratum growing in the northern Chihuahuan desert was determined during a spring drought and following the autumn reproductive phase of growth. The objectives were (i) to determine the whole-plant carbon balance after a fifty-two day drought when photosynthetic capacity was severely repressed, and (ii) to determine the whole-plant carbon balance during favourable soil-water conditions prevalent after the autumn reproductive period. (2) Water stress severely repressed diurnal photosynthetic capacity during drought. The below-ground biomass, however, consisted of suberized roots with low respiratory activity. The net result was a positive whole-plant carbon gain of 2{\textperiodcentered}6 mg C g dry wt -1 day -1. \ (3) Precipitation, amounting to 1{\textperiodcentered}12 cm, ended the fifty-two-day drought, and increased the whole-plant carbon gain approximately six-fold. (4) The mean root/shoot quotient was 1{\textperiodcentered}9 during the spring drought and 0{\textperiodcentered}6 in the autumn. Reproductive tissue accounted for 13-34\% (mean= 22\%) of the above-ground biomass in the autumn. (5) Following reproductive growth, when soil-moisture conditions were favourable, the root system comprised suberized roots, non suberized nodal roots and other nonsuberized roots. Although the last two root types had high respiration rates, their presence in low quantities and low soil temperatures resulted in below-ground respiration approximately equal to that during drought. The whole-plant carbon gain during September was 17{\textperiodcentered}2 mg C g dry wt -1 day -1.

}, doi = {10.2307/2260986 }, url = {/files/bibliography/351.pdf}, author = {Sisson, W.B.} } @article {51697, title = {Contributions of soil fauna to decomposition and mineralization processes in semiarid and arid ecosystems}, journal = {Arid Soil Research and Rehabilitation}, volume = {3}, year = {1989}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1989}, pages = {199-215}, abstract = {

This review examines the following questions: (1) do soil fauna play an important regulatory role in decomposition and mineralization processes in arid and semiarid ecosystems? (2) if important, what are the mechanisms of the rate regulation, and (3) what are the management implications of these relationships? Because termites process more than half of the surface litter in hot deserts, this review focuses on faunal effects on buried litter and roots. Elimination of soil arthropods reduced rates of mass loss and coupled mass loss to soil moisture. With arthropods present soil moisture accounted for less than 50\% of the variation in mass loss. Other experiments demonstrated that regulation of mass loss results from predatory mites regulating the population density of grazers, thereby preventing overgrazing of the fungi and bacteria. The regulation of microbial grazers by soil microarthropods also affects rates of mineralization and nutrient immobilization. Populations of small fungus grazing mites (Tarsonomidae) affect mineralization directly. Microarthropods tend to uncouple mineralization from abiotic constraints. Fluctuations in microbial populations and soil fauna are more a function of substrate availability than of abiotic regulation. Pulses in organic matter inputs result in periods of nutrient immobilization, the extent of which is a function of the rate of recovery of populations of key soil microarthropods.

}, keywords = {article, articles, decomposition, belowground, decomposition,soil fauna, journal, journals, microarthropod, also SEE , soil fauna,decomposition, soil fauna,mineralization processes, soil, microarthropods, soil, microbial, soil, mites}, doi = {10.1080/15324988909381199}, url = {files/bibliography/JRN00092.pdf}, author = {Walter G. Whitford and L. W. Parker} } @article {51714, title = {Changes in grass basal area and forb densities over a 64-year period on grassland types of the Jornada Experimental Range}, journal = {Journal of Range Management}, volume = {41}, number = {3}, year = {1988}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {May 1, 1988}, pages = {186-192}, abstract = {

Between 1915 and 1932, permanent 1 X 1-m quadrats were established on grasslands of the Jornada Experimental Range in southern New Mexico. Quadrat records accumulated from 1915 to 1979 on grasslands dominated by black grama [Bouteloua eriopoda (Torr.) Torr.], poverty threeawn (Aristida divaricata Willd.), tobosa [Hiltuia mutica (Buckl.) Benth.], and burrograss (Scleropogon brevifolius Phil.) were used to examine changes in perennial grass basal area and forb densities. Quadrats originally dominated by black grama had large reductions in basal area during droughts, and basal area increased slowly following droughts. By 1979, black grama no longer occurred on 77\% of the quadrats. Quadrats originally dominated by poverty threeawn changed to a mesquite (Prosopis glandulosa Torr. var. glandulosa) type. Perennial grass basal area on quadrats dominated by tobosa and burrograss decreased during droughts, but recovery was relatively rapid. Antecedent precipitation was associated with only 10 to 38\% of the variation in perennial grass basal area. Perennial forb densities were low and fluctuated among years in all types. Annual forbs and grasses displayed large fluctuations in densities among years. The necessity of basing management of Chihuahuan Desert ranges on the perennial grass component is borne out by the low densities of palatable perennial forbs, and the extreme fluctuation and unpredictability in densities of annual forbs and grasses.

}, keywords = {arid rangeland, black grama, burrograss, poverty threeawn, tobosa}, doi = {10.2307/3899165 }, url = {/files/bibliography/329.pdf}, author = {Gibbens, Robert P. and Reldon F. Beck} } @article {51739, title = {Cover of spring annuals on nitrogen-rich kangaroo rat mounds in a Chihuahuan Desert grassland}, journal = {The American Midland Naturalist}, volume = {120}, number = {2}, year = {1988}, note = {//NMSU//LTER I//}, month = {1988}, pages = {443-447}, abstract = {

Species composition and cover of spring annual plant communities on banner-tailed kangaroo rat (Dipodomys spectabilis) mounds in a northern Chihuahuan Desert grassland differed from those on intermound areas. After seasons of adequate precipitation, cover of annual plants was greater on mounds than on adjacent areas; dominant species on mounds were those known to increase with nitrogen fertilization. Soil nitrogen content was consistently higher on mound soils than in intermound soils; however, plant cover on mounds was not different from intermound areas following periods of limited precipitation despite differences in nitrogen levels. Patterns of species composition and cover of annual plants on kangaroo rat mounds are attributed to differential species responses to water and nutrient availabilities.

}, keywords = {article, articles, Dipodomys, disturbance, annual plants, grassland, journal, journals, kangaroo rat mounds, kangaroo rat mounds, annual plants, kangaroo rat mounds, nitrogen, kangaroo rat mounds, plant cover, kangaroo rat mounds, species composition, nitrogen, plant cover, rodent, Dipodomys, spring annuals}, doi = {10.2307/2426018 }, url = {files/bibliography/JRN00070.pdf}, author = {Daryl L. Moorhead and F. M. Fisher and Walter G. Whitford} } @article {51740, title = {Canopy architecture of Larrea tridentata (D. C.) Cov., a desert shrub: foliage orientation and direct beam radiation interception}, journal = {Oecologia (Berlin)}, volume = {75}, year = {1988}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1988}, pages = {54-60}, abstract = {At sites in the United States, creosote bushes (Larrea tridentata (DC.) Cov.) orient foliage clusters predominantly toward the southeast . Foliage of bushes at the southernmost distribution extreme in Mexico shows no predominant orientation. Clusters at all sites are inclined between 33 degrees and 71 degrees form the horizontal. Inclinations are steeper in the drier and hotter Mojave Desert than in the Chihuahuan Desert. Individual leaflets, though not measured, appear more randomly oriented than foliage clusters. In several populations studied, branches were shorter in the southeastern sectors of the crown, reducing self-shading early in the morning. Measurements of direct beam radiation interception by detached branches, using digital image processing, indicated that foliage clusters oriented toward the southeast exhibited less self-shading during spring mornings than clusters oriented northeast. This effect was not apparent at the summer solstice. This type of canopy architecture may tend to minimize self-shading during the morning hours when conditions are more favorable for photosynthesis, resulting in an improved daily water use efficiency.}, keywords = {article, articles, journal, journals, Larrea,canopy architecture, Larrea,leaf orientation, Larrea,light interception}, author = {Neufeld, Howard S. and Meinzer, Frederick C. and Wisdom, Charles S. and Sharifi, M. Rasoul and P. Rundel and Neufeld, Mollie S. and Goldring, Yoram and Gary L. Cunningham} } @article {51774, title = {Chihuahuan Desert annuals: importance of water and nitrogen}, journal = {Ecology}, volume = {68}, number = {6}, year = {1987}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1987}, pages = {2032-2045}, abstract = {

We examined the effects of water supplementation and nitrogen amendment on biomass, cover, and density of annual plants on a termite-free and a termite-present area in the Chihuahuan Desert. Soil moisture was higher in the termite than in the termite-free plots, and in the watered than in the unwatered plots during the spring and summer. There were no differences in soil moisture among plots during the winter. Soil nitrogen was higher in the termite-free than in the termite plots. There were no differences in total plant biomass produced in termite and termite-free areas. There were significant differences in relative abundances of species among treatments. Natural rainfall was sufficient for maximum spring-annual biomass development on all plots except for the termite-free unfertilized, unwatered plots. there were the direst plots but had high soil nitrogen. Most of the herbaceous species responded to the water amendments by lengthening growing seasons, increasing density, or increasing biomass. When there was sufficient water for most of the spring annuals, high soil nitrogen levels favored increased densities and biomasses of Descurainia pinnata and Lepidium lasiocarpum. The absence of C4 summer annuals in the high-nitrogen plots suggests that relatively high soil nitrogen adversely affected the summer annuals. Termite-free watered plots had higher soil moisture than the termite-unwatered plots, but summer annuals were relatively abundant in the latter. Water amendments had a greater effect on the species abundances in the termite-free area than in the one with termites. In the area with termites, nitrogen amendments had a greater effect on species abundances. Species diversity and richness were affected by site fertility as was species composition. This study demonstrates that we must understand patterns of soil nitrogen availability and processes affecting nitrogen availability in addition to water availability, in order to understand productivity and species composition of Chihuahuan Desert annual plants.

}, keywords = {annual plant, density, annual plant, phenology, annual plant,productivity, annual plant,soil moisture, annual plant,soil nitrogen, annual plant,termite, article, articles, irrigation, also SEE , journal, journals, nitrogen, amendment, phenology,annual plant, plant community, composition, soil moisture, soil, nitrogen, termite}, doi = {10.2307/1939894}, url = {files/bibliography/JRN00052.pdf}, author = {Julio R. Gutierrez and Walter G. Whitford} } @article {51778, title = {Coyotes, guard dogs and electric fences}, journal = {Rangelands}, volume = {9}, year = {1987}, month = {1987}, pages = {102-105}, abstract = {

In 1983 sheep were introduced on the Jornada Experimental Range (JER) in southwest New Mexico to determine if cattle and sheep grazing would lead to more efficient utilization of the range. It was rumored that there were many coyotes in the area and predation was expected to be a serious problem. A year after the sheep were introduced, the Fishery and Wildlife Sciences Department at New Mexico State University (NMSU) in cooperation with USDA estimated from scent-post visitations and helicopter gunning that coyote density was 1 per 2.7 square miles (Kumm 1985).

}, keywords = {fencing, predation, sheep}, url = {/files/bibliography/319.pdf}, author = {Clarence V. Hulet and Shupe, W. Larry and V. W. Howard Jr.} } @mastersthesis {51796, title = {Canopy manipulations, gas exchange and water relations of a perennial bunchgrass}, year = {1987}, note = {//??//NONE//}, month = {1987}, pages = {93}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, grass,physiology, physiology,grass, plant,physiology, theses, thesis}, author = {R.S. Senock} } @conference {51808, title = {Cattle and sheep activities under simultaneous stocking of arid rangeland}, booktitle = {39th Annual Meeting, Society for Range Management}, year = {1986}, month = {1986}, pages = {141}, abstract = {Within each of three seasons (i.e., dormancy, ephemeral and perennial growth) a series of observations were made on cattle and sheep between sunrise and sunset. Grazing, walking, standing, and lying events were recorded with an electronic, hand-held data logger that contained a real-time clock. Discussion of the data includes evaluating the locations within the paddock where the various activities took place and the implications this type of data has in developing mixed species grazing strategies.}, keywords = {activities, arid rangeland, cattle, sheep, simultaneous stocking}, author = {D.M. Anderson and J. N. Smith and Clarence V. Hulet} } @proceedings {51811, title = {Conference Proceedings}, year = {1986}, note = { //OTHER//NONE//}, month = {October 20-21, 1}, publisher = {Allen Press}, address = {Chihuahuan Desert Research Institute, Sul Ross State University}, keywords = {abstract, abstracts, archaeology, Chihuahuan desert, vegetation, climate,pleistocene, conference, conference proceedings, conferences, pesticide, pleistocene,climate, proceeding, proceedings}, author = {Barlow, Jon C. and Michael A. Powell and Timmermann, Barbara N. (eds.)} } @article {51813, title = {The conditions required to isolate and maintain viable cotton (Gossypium hirsutum L.) microspores}, journal = {Plant Cell Reports}, volume = {5}, year = {1986}, month = {1986}, pages = {405-408}, abstract = {

Cultural systems developed for the successful production of haploid plants from anther and microspore culture of a number of species are lethal to cotton microspores. Components of these systems were examined individually and in simple combinations to determine their specific effect on cotton microspore viability during isolation and culture. An organically buffered pH of 7.0 was critical for survival. The addition of potassium salts, near standard concentrations used for other species, enhanced survival and the cytoplasmic appearance of isolated microspores. Severe toxicity resulted from ammonium, calcium and magnesium salts, and these ions were tolerated only at very low concentrations. Iron, glutamine, serine, inositol, vitamins, and trace minerals were generally not detrimental to microspores at standard concentrations. An isolation and cultural maintenance system was developed that yields large quantities of healthy, viable cotton microspores. This initial step allows for further research in inducing cotton microspores to divide and undergo embryogenesis.

}, doi = {10.1007/BF00269627}, url = {/files/bibliography/710.pdf}, author = {J.R. Barrow} } @mastersthesis {51819, title = {Comparative seasonal food habits of black-tailed jackrabbits and cattle on semidesert rangeland}, year = {1986}, note = {//NMSU//NONE//}, month = {1986}, pages = {68}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {Seasonal diets of black-tailed jackrabbit (Lepus Californicus) and dietary overlap between black-tailed jackrabbits and cattle were studied from May 1984 to May 1985 in three vegetation types in southwestern New Mexico. A microhistological technique was used to identify botanical composition of fecal samples....Although jackrabbit and cattle ate some of the same species, they did not eat them in similar proportions. Food overlap was slight during winter, and 36\% in spring. The diet overlap bwtween these animals was greater during early spring when both animal species preferred green forage.}, keywords = {cattle, food habit \& rabbits, cattle,food habits, dissertation, dissertations, food habits,cattle, food habits,Lepus, lagomorph, Lepus, Lepus, food habits, mammal, SEE , rabbit, SEE , theses, thesis}, author = {Fatehi, Mohammad} } @conference {51823, title = {Canopy and ground cover inside and outside of livestock exclosures on brush ranges in southern New Mexico with up to 50 years of protection}, booktitle = {39th Annual Meeting, Society for Range Management}, year = {1986}, month = {1986}, pages = {133}, keywords = {brush ranges, canopy, groundcover, inside, livestock exclosures, outside}, author = {Gibbens, Robert P. and Reldon F. Beck and T.L. Atwood} } @mastersthesis {51825, title = {Changes in vegetation following herbicidal control of honey mesquite (Prosopis juliflora) (Swartz) DC. var. glandulosa (Torrey) Cockerell) in southern New Mexico}, year = {1986}, note = {//NMSU//NONE//}, month = {1986}, pages = {123}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {Herbaceous and shrubby vegetation on New Mexico State University College Ranch was studied to find out changes resulting from herbicidal control of honey mesquite (Prosopis juliflora var. glandulosa). The soil of the study area belongs to Berino-Dona Ana Association. Density of all species, aerial cover of shrubs, and basal cover of herbaceous species were measured in summers of 1985 and 1986. Density and basal cover of cool season annual forbs were recorded in spring 1986. Vegetational patterns around honey mesquite shrubs were also studied and light intensity measured in different zones, beneath and outside the mesquite canopy.}, keywords = {brush control, Prosopis, dissertation, dissertations, herbicide, Prosopis, Prosopis, herbicidal control, Prosopis, vegetation patterns, theses, thesis, vegetation changes, Prosopis}, author = {Haque, Zahoorul} } @article {51843, title = {A conceptual model of primary productivity, decomposition, and nitrogen cycling in the Chihuahuan creosotebush desert}, journal = {Tree Physiology}, volume = {2}, year = {1986}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1986}, pages = {215-222}, abstract = {

The conceptual framework for a simulation model of primary productivity, decomposition and nitrogen cycling in a shrub-dominated desert ecosystem in southern New Mexico is presented. This model is based on our previous attempt to simulate carbon allocation patterns in the desert shrub Larrea tridentata Cov., which demonstrated that moisture patterns alone are insufficient to predict desert productivity. These results, as well as others, suggest that mineral nutrients, especially nitrogen, may also be an important determinant of productivity in arid environments. Our current research in the Chihuahuan desert is directed towards elucidating the numerous biotic and abiotic interactions that determine the rates and directions of carbon, nitrogen and water fluxes in this ecosystem. The development of this working model will serve as a tool to accomplish three major objectives: (1) to synthesize the large amounts of existing data on decomposition and nitrogen cycling in deserts, (2) to quantify our present state of knowledge about the structure and function of ecosystem components important in carbon and nitrogen dynamics in deserts, and (3) to address hypotheses concerning the complex mechanisms of interactions and feedbacks among the organisms involved in carbon and nitrogen exchanges in deserts.

}, keywords = {article, articles, creosotebush, decomposition, journal, journals, Larrea, decomposition, Larrea, productivity, Larrea,nitrogen cycling, model, conceptual, model, decomposition, model, Larrea, model, nitrogen cycling, model, primary production, nitrogen cycling, primary production, Larrea}, doi = {10.1093/treephys/2.1-2-3.215}, url = {files/bibliography/JRN00028.pdf}, author = {Daryl L. Moorhead and J. F. Reynolds and Walter G. Whitford} } @mastersthesis {51848, title = {Control of honey mesquite with triclopyr and picloram + clopyralid on the New Mexico State University College Ranch}, year = {1986}, note = {//NMSU//NONE//}, month = {1986}, pages = {55}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Mesquite (Prosopis glandulosa) and fourwing saltbush (Atriplex canescens) were two of the major shrubs occupying a study site on the New Mexico State University College Ranch. The objective of this study was to examine the effects of triclopyr, and picloram + clopyralid, for control of mesquite and fourwing saltbush. Triclopyr was effective in reducing the canopy cover of mesquite and fourwing saltbush at 0.56 kg ai/ha rate. The percentage of dead mesquite plants was 22.2\% and fourwing saltbush control was 12.5\%. Picloram + clopyralid, at a rate of 0.14 + 0.14 kg ai/ha was not an effective treatment. Piclorma + clopyralid, at a rate of 0.28 + 0.28 kg ai/ha, killed 34.37\% of mesquite and 59\% of fourwing saltbush plants.}, keywords = {Atriplex,herbicide, brush control, dissertation, dissertations, herbicide, picloram + clopyralid, herbicide, triclopyr, herbicide,clopyralid, herbicide,picloram, herbicide,triclopyr, plant,Atriplex, Prosopis,herbicide, theses, thesis}, author = {Poyga, Dambidie F.} } @proceedings {51852, title = {Chihuahuan Climate}, year = {1986}, note = { //LOCAL//NONE//ProCite field[6]: In}, month = {October 20-21, 1}, pages = {40-63}, publisher = {Allen Press}, address = {Chihuahuan Desert Research Institute, Sul Ross State University}, abstract = { As a result of increased pressure being exerted upon arid, and particularly semiarid zones to improve the use of renewable resources, a data base in excess of five megabytes representing monthly climate values has been verified and recorded on computer tape. The climate averages and generalizations used in this study are based upon information from approximately 140 weather stations in the desert. These data are being used to identify and characterize the features are generally homogenous, regional climatological analysis provides significant aid in identifying introduced plants with economic potential. One of the more dramatic findings of this study was the importance of tropical revolving storms, some to which reach hurricane intensity, as a source of perceptible water. Based upon a limited sample, it was found that approximately 55\% of the annual precipitation falling in El Paso, Texas, was the result of tropical revolving storms. A scenario using the de Martonne aridity indices with the mean and minimum and maximum extreme precipitation for stations in the State of Chihuahua clearly illustrates the potential for desertification and other problems with the use of natural resources.}, keywords = {abstract, abstracts, Chihuahuan Desert,climate, climate,Chihuahuan Desert, conference, conference proceedings, conferences, proceeding, proceedings}, author = {Schmidt, Robert H. Jr.}, editor = {Barlow, Jon C. and Michael A. Powell and Timmermann, Barbara N. (eds.)} } @article {51883, title = {Controlling shrubs in the arid Southwest with tebuthiuron}, journal = {Journal of Range Management}, volume = {38}, year = {1985}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {1985}, pages = {391-394}, abstract = {

Various rates of tebuthiuron pellets were aerially applied on rangelands in the Southwest to determine effects on noxious shrubs. Creosotebush (Larrea tridentata) and tarbush (Flourensia cernua) shrubs were controlled with 0.4 and 0.3 kg active ingredient (a.i.)/ha, respectively, of tebuthiuron pellets. About 1.1 kg a.i./ha of tebuthiuron pellets controlled honey mesquite (Prosopis glandulosa) growing on loamy sands or sandy loams. About 0.6 and 0.5 kg a.i./ha of tebuthiuron pellets controlled whitethorn acacia (Acacia constricta) and desert zinnia (Zinnia pumila), respectively. Higher rates of tebuthiuron are needed to control those shrubs on deep, fine textured soils than on shallow, coarse textured soils.

}, url = {/files/bibliography/281.pdf}, author = {C.H. Herbel and Morton, H.L. and Gibbens, Robert P.} } @article {51890, title = {CALDEP: a regional model for CaCO3 (caliche) deposition in southwestern deserts}, journal = {Soil Science}, volume = {139}, number = {5}, year = {1985}, note = {//NMSU//LTER I//}, month = {1985}, pages = {468-481}, abstract = {

Our objective was to develop and validate a regional model for CaCO3 deposition in desert soils of the southwestern United States. There were five major components in the simulation model, an evportranspiration model, chemical thermodynamic relationships, soil parameterization, and a soil water and CaCO3 flux model.

For the present climate, a cold-dry Pleistocene climate, and a cool-wet (summer) Pleistocene climate, the model predicted a shallower depth for the calcic horizon than was found in field soils. However, the model was compatible with field soils if one assumed that most pedogenic carbonate formed during a cool-wet (winter) Pleistocene climate. The model was highly sensitive to the frequency of extreme precipitation events and to soil water-holding capacity. The biotic factor played an important role in CaCO3 deposition through its control of soil CO2 concentrations and evapotranspiration rates. The range in predicted CaCO3 deposition rates agreed with the rates for most field studies (1 to 5 g/m2/yr); also, the model predicted an increasing rate of CaCO3 deposition with increasing precipitation, which agreed with field studies. The model is a valuable research tool for evaluating the role of state factors on soil CaCO3 deposition.

}, keywords = {article, articles, calcium carbonate,deposition model, caliche, deposition model, journal, journals, model, calcium carbonate deposition, model, CALDEP, model,regional}, doi = {10.1097/00010694-198505000-00014}, author = {G. M. Marion and W. H. Schlesinger and P. J. Fonteyn} } @proceedings {51896, title = {CO2 exchange of the above-ground and below-ground components of Kleingrass (Panicum coloratum L.) during drought in the northern Chihuahuan Desert}, year = {1985}, month = {1985}, pages = {336-338}, address = {Kyoto, Japan}, abstract = {

The effect a 52 day drought had on the die! whole-plant carbon balance of kleingrass (Panicum coloratum L.) growing in the northern Chihuahuan desert was determined. Whole-plant C02 inputs (photosynthesis) and outputs (belowground and aboveground respiration) were measured on day 52 of the drought (June 23, 1981) and 2 days following 1.12 cm of precipitation that occurred on June 24, 1981.

}, keywords = {carbon balance, desert, drought, photosynthesis, root respiration}, url = {/files/bibliography/282.pdf}, author = {Sisson, W.B.} } @article {51903, title = {Cytotype distribution of Atriplex canescens (Chenopodiaceae) of southern New Mexico and adjacent Texas}, journal = {The Southwestern Naturalist}, volume = {29}, number = {2}, year = {1984}, note = {//LOCAL//NONE//}, month = {1984}, pages = {223-228}, abstract = {Populations of Atriplex canescens in southern New Mexico and western Texas include diploids (2n = 18), tetraploids (2n = 36), and hexaploids (2n = 54). Tetraploids are the most common and widely distributed cytotype. Diploids are limited to specific areas and hexaploids are rare except in the Rio Grande Valley. Tetraploids occur primarily on finer textured soils on the slopes and mesas. Diploids are found on coarser sandy soils and sand dune areas. The hexaploids seem getter adapted to the silty clay flood plain soils of the Rio Grande Valley. The occurrence of hybridization between ploidy levels in demonstrated by 3x and 5x chromosome counts, indicating that gene exchange between ploidy levels occurs.}, keywords = {article, articles, Atriplex,genetics, genetics,Atriplex, journal, journals, plant,Atriplex}, author = {M.P. Dunford} } @article {51904, title = {Coordinated prey capture by Novomessor cockerelli (Hymenoptera: Formicidae)}, journal = {New York Entomological Society}, volume = {91}, number = {4}, year = {1984}, note = {//NMSU//NONE//}, month = {1984}, pages = {328-332}, abstract = {

Novomessor cockerelli uses coordinated behavior to subdue large orthopteran prey. When a partially disabled grasshopper is encountered, the first worker finding it mounts the dorsum of the grasshopper and clamps its mandibles over the wings, thus preventing escape by flight. Workers which arrive subsequently systematically remove or subjugate additional appendages. Behavioral coordination allows N. cockerelli to efficiently exploit large orthopterna prey which would otherwise escape if workers attempted to capture these individually.

}, keywords = {ant, prey capture, ant,Novomessor, article, articles, invertebrate,also SEE , journal, journals, Novomessor,foraging strategy, Novomessor, Novomessor,prey capture, Orthoptera, Novomessor prey}, url = {files/bibliography/84-NYEntmlgclScty-Whitford.pdf}, author = {Harold G. Fowler and Walter G. Whitford} } @article {51920, title = {Carbon and nitrogen dynamics during the decomposition of litter and roots of a Chihuahuan Desert annual Lepidium lasiocarpum}, journal = {Ecological Monographs}, volume = {54}, number = {3}, year = {1984}, note = {//NMSU//LTER ??//}, month = {1984}, pages = {339-360}, abstract = {

Carbon and nitrogen dynamics were analyzed during the decomposition of litter and roots of the desert ephemeral pepperweed (Lepidium lasciocarpum). We treated litter bags with the insecticide chlordane and the fungicides benomyl and captan to eliminate or restrict groups of soil biota. Data from this study re-emphasize the importance of microarthropods as regulators or decomposition in deserts and suggest that predation by nematodes or protozoa on bacteria and fungi contributes to rate regulation. Nitrogen flux data suggest that when spring ephemeral plant production is high, decomposition of ephemeral roots with attendant nitrogen immobilization can reduce the nitrogen available to creosotebush, Larrea tridentata, thus reducing shrub production. Higher taxa of soil biota, i.e., nematodes and miroarthropods, may thus be important regulators of nitrogen fluxes and of mass loss in decomposition.

}, keywords = {abiotic,decomposition, acarina, SEE , annual plant,decomposition, article, articles, bacteria,decomposition, carbon dynamics,decomposition, decomposition,Lepidium, decomposition,litter, decomposition,microarthropods, decomposition,root, fungi,decomposition, fungicide, Benomyl, fungicide, Captan, insecticide, Chlordane, journal, journals, Lepidium, microarthropod,decomposition, minerilization, nematode,decomposition, nitrogen dynamics,decomposition, nutrient cycling,decomposition, plant carbon,decomposition, plant nitrogen, protozoa,decomposition}, doi = {10.2307/1942501}, url = {files/bibliography/84-EcologicalMonographs-Whitford2.pdf}, author = {L. W. Parker and Perseu F. Santos and Janice Phillips and Walter G. Whitford} } @article {51923, title = {A comparison of surface and buried Larrea tridentata leaf litter decomposition in North American hot deserts}, journal = {Ecology}, volume = {65}, year = {1984}, note = {//NMSU//NONE, LTER//}, month = {1984}, pages = {278-284}, abstract = {

We conducted studies of mass losses from surface and buried litter bags in four North American hot desert areas to test the following hypotheses: (1) leaf litter disappearance in hot deserts is independent of actual evapotranspiration, (2) buried litter disappearance is a function of actual evapotranspiration, (3) the patter of microarthropod colonization of buried leaf litter is a function of the stage of decomposition, and (4) elimination of microarthropod results in reduced rates of decomposition and increased numbers of free-living nematodes.

}, keywords = {article, articles, decomposition,Larrea litter, insecticide, Chlordane, journal, journals, Larrea,litter decomposition, litter decomposition,Larrea, litter, microarthropods, microarthropod,decomposition, nematode,decomposition}, doi = {10.2307/1939480}, url = {files/bibliography/84-Ecology-Whitford.pdf}, author = {Perseu F. Santos and Ned Z. Elkins and Yosef Steinberger and Walter G. Whitford} } @proceedings {51929, title = {Concentration of water on rangeland for forage production}, year = {1984}, month = {1984}, address = {Gunnison, CO}, author = {J.M. Tromble} } @article {51935, title = {Comparisons among pollen viability measurments methods in cotton}, journal = {Crop Science}, volume = {23}, year = {1983}, month = {July-August 1983}, pages = {734-736}, keywords = {cotton, pollen, viability}, url = {/files/bibliography/99-010.pdf}, author = {J.R. Barrow} } @article {51971, title = {Carbon balance of Yucca elata Engelm. during a hot and cool period in situ}, journal = {Oecologia}, volume = {57}, year = {1983}, month = {1983}, pages = {352-360}, abstract = {

Respiratory activity of intact, attached roots was measured under field and controlled conditions. Root respiration of Yucca elata Engelm. was highly temperature dependent: Q10 values decreased from 2.1 (12-22{\textdegree} C) to 1.7 (26-36{\textdegree} C) as temperatures increased. Respiration ceased after 5 h at 42{\textdegree} C. In the field, in August, when net leaf photosynthesis was severely depressed, the die! fluctuation in the respiration rate of suberized and partially suberized roots was predominantly a function of temperature. A photoperiod-associated rise in respiration rates apart from temperature response occurred in February for nonsuberized, partially suberized, and suberized roots when active net photosynthesis occurred throughout the photoperiod. In whole-plant root systems, respiratory C02 was 3.2 and 4.3 mg C02. g Dw -1. d -1 in August and February, respectively, when adjusted for the proportion of suberized and nonsuberized lateral roots. On a whole-plant basis, 0.89 mg C {\textperiodcentered} g DW -1 {\textperiodcentered} d -1 was gained during February and 0.46 mg C {\textperiodcentered} g DW -1 {\textperiodcentered} d -1 was lost in August. The belowground: above ground ratio of whole-plants in situ was 0.42 on a shallow soil where vertical root growth was limited to a soil depth of 68 cm and ranged from 1.29 to 5.94 (.X= 3.31) in deep sands. No leaf dark fixation of C02 was observed in field plants during August and February, nor in well-watered plants or plants subjected to drought in laboratory studies. Although small die! fluctuations in leaf acidity occurred in both field and greenhouse-grown plants, results of this study suggest that Y. elata is a C3 plant.

}, url = {/files/bibliography/246.pdf}, author = {Sisson, W.B.} } @article {51973, title = {The contribution of rodents to decomposition processes in a desert ecosystem}, journal = {Journal of Arid Environments}, volume = {6}, year = {1983}, note = {//NMSU//NONE, LTER//}, month = {1983}, pages = {177-181}, abstract = {

Excavations made by desert rodents during the late non-growing season (April-August) accumulated litter amounts varying between 5.2 and 17.6 kg/ha and over a 1-year period 55.9 kg/ha of litter was buried in such excavations. There was a higher nitrogen content in litter in October, 17.6 +- 0.5 ug/g than the rest of the year, 1.5 +- 1.4 ug/g. Litter bag studies of decomposition of small quantities of buried litter similar to that accumulated in rodent excavations exhibited higher rates of decomposition than larger quantities of buried litter reported in the literature. Rodent excavating activity increases rates of decomposition and organic matter turnover and may effect the distribution of ephemeral plants in warm desert ecosystems.

}, keywords = {article, articles, journal, journals, litter decomposition,rodents, litter,nitrogen, nitrogen,litter, rodent,decomposition processes}, doi = {10.1016/S0140-1963(18)31531-3}, url = {files/bibliography/JRN00009.pdf}, author = {Yosef Steinberger and Walter G. Whitford} } @article {51974, title = {The contribution of shrub pruning by jackrabbits to litter input in a Chihuahuan Desert ecosystem}, journal = {Journal of Arid Environments}, volume = {6}, year = {1983}, note = {//NMSU//NONE, LTER//}, month = {1983}, pages = {183-187}, abstract = {

Jackrabbits, Lepus californicus, prune stems from creostoesbushes Larrea tridentata during the dry winter months, eating the previous season new woody stems allowing the leaves and old wood to fall the the ground. This unconsumed material was 66 kg/ha/year of stem and 35 kg/ha/year of leaves; approximately one-fifth of the quantity of shrub litter input by natural infall. Jackrabbits preferentially pruned stems of shrubs with higher tissue moisture content. Rabbits tend to prune stems from the same shrubs in successive years.

}, keywords = {article, articles, journal, journals, Lagomorpha, Lepus, Larrea,rabbit pruning, litter,shrub pruning, rabbit,shrub pruning, shrub, litter input, shrub, rabbit pruning}, doi = {10.1016/S0140-1963(18)31532-5}, url = {files/bibliography/JRN00010.pdf}, author = {Yosef Steinberger and Walter G. Whitford} } @proceedings {51982, title = {The contributions of soil fauna to nutrient cycles in desert systems}, year = {1983}, note = { //NMSU//LTER I//ProCite field[6]: In}, month = {19821983}, pages = {49-59}, publisher = {Imprimeur Dieu-Brichart, Ottignies-Louvain-la-Neuve}, address = {Louvain-la-Neuve, Belgium}, abstract = { A significant fraction of the nitrogen turnover and of other nutrients in the Chihuahuan desert is through termites and back to the system by the termite predators. Important fluxes of N through termites include consumption of dead plant material, fixation of atmospheric N by gut symbionts and production of N enriched gallery carton. Use of biocides to eliminate soil fauna showed that nitrogen was immobilized in ephemeral plant roots and absence of microarthropods resulted in marked reduction of nitrogen turnover and increased soil organic nitrogen. In untreated roots, nitrogen fluxes were primarily a function of microarthropod activity but in the absence of microarthropods, bacteriophagous nematodes and protozoans accounted for most of the N fluxes.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, decomposition, nutrient cyling, nematode, nutrient cycling, nitrogen cycling, nutrient cycling, soil fauna, proceeding, proceedings, Prostigmata, soil fauna, nutrient cycling, termite, nutrient cycling}, author = {Walter G. Whitford and D. W. Freckman and L. W. Parker and Douglas Schaefer and Perseu F. Santos and Yosef Steinberger}, editor = {Lebrun, Ph. and Andr{\'e}, H. M. and De Medts, A. and C. Gr{\'e}goire-Wibo, C. and Wauthy, G. (eds.)} } @article {51994, title = {Carrion location efficiency in burying beetles, Nicrophorus carolinus (L.) (Silphidae)}, journal = {Southwest National}, volume = {27}, number = {1}, year = {1982}, note = {//USDA//NONE//}, month = {1982}, pages = {11-15}, abstract = {Efficiency of burying beetles in locating carrion was observed at 102 rat carcasses during June-July, 1980, at two study areas in Dona Ana County, New Mexico. Location time varied from 24 to 100 h, except where putrifying carrion already was present or had been removed recently from the site. In these situations, location time was reduced to less than or equal to 6 h, supporting an hypothesis for priming effects upon location efficiency. Location efficiency ranged from 10 to 80\% of available carcasses. Of 37 carcasses colonized, 38\% were occupied by single beetles and 27\% were occupied by two beetles. The largest assemblage observed at a single carcass was 14 beetles. Sex identification was obtained for 32 beetles collected from 11 carcasses during the final observation period. All single individuals collected were females and all pairs of beetles included at least one female. Larger assemblages were composed of both males and females.}, keywords = {article, articles, food habits, burying beetle, insect, burying beetle, insect, Nicrophorus,food habits, journal, journals, Nicrophorus,food habits}, author = {Marsha R. Conley} } @booklet {52003, title = {Causes and Effects of Stratosphereic Ozone Depletion: An Update}, year = {1982}, month = {1982}, pages = {352 pp}, publisher = {National Academies Press}, address = {Washington, D.C.}, keywords = {causes and effects, stratosphereic ozone depletion}, url = {http://www.nap.edu/openbook.php?record_id=319\&page=R1}, author = {Friend, J.P. and Henderson, M.M. and Jagger, J. and Klein, R.M. and Parrish, J.A. and Seliger, H.H. and Setlow, R.B. and Sisson, W.B.} } @proceedings {52007, title = {Copper, manganese and zinc status of beef cows grazing dormant forage on arid range, as affected by supplemental feeds}, volume = {33}, year = {1982}, month = {1982}, pages = {239-241}, keywords = {arid range, beef cattle, copper, dormat forage, manganese, supplemental feeds, zinc}, author = {Head, M.A. and Geoffrey Smith and Trujillo, P.A. and C.H. Herbel and Sanson, D.} } @article {52024, title = {Contributions of subterranean termites to the {\textquoteright}economy{\textquoteright} of Chihuahuan desert ecosystems}, journal = {Oecologia (Berlin)}, volume = {55}, year = {1982}, note = {//NMSU//US-IBP//}, month = {1982}, pages = {298-302}, abstract = {

We examined the role of subterranean termites in decomposition of cattle dung, various herbaceous plant species and wood in a Chihuahuan desert ecosystem. From July-September, termites removed dung at a rate of 0.63 g/day-1 accounting for a percent mass loss of 19.5-100\%. During the autumn subterranean termites consumed more than 50\% of the leaves of the shrub Larrea tridentata, the grass Erioneuron pulchellum and annual plant Lepidium lasiocarpum and Baileya multiradiata but used very little of two other annuals Eriastrum diffusum and Eriogonum trichopes. Yucca inflorescence stalks on plots with termites lost 23\% of their original mass in 30 months while those on termite free soils lost 11\%. Elimination of termites resulted in reduction of fluff grass, Erioneuron pulchellum biomass, thereby affecting the structure of the ecosystem.

}, keywords = {article, articles, decomposition,termites, journal, journals, pesticide, Chlordane, termite,decomposition}, doi = {10.1007/BF00376915}, url = {files/bibliography/82-Oecologia-Whitford.pdf}, author = {Walter G. Whitford and Yosef Steinberger and George Ettershank} } @proceedings {52048, title = {Consumption rates of desert grassland herbivores}, year = {1981}, note = {//USDA//US-IBP// Updated 12/17/2005ProCite field[6]: In}, month = {June 15-24, 1981}, pages = {465-467.}, publisher = {Westview Press}, address = {Lexington, Kentucky, U.S.A.}, abstract = {Studies were conducted on a desert grassland range in southern New Mexico for 3 years to determine relative consumption rates of the main herbivores utilizing these range areas. Consumption by all herbivores averaged less than 5\% of the above-ground net primary productivity for the 3 years of the study. Highest consumption rates among the herbivore groups were for cattle, which consumed an average of 4.3 g/m2 during the study. Consumption by rodents was fairly high during the first year of the study when rodent densities were high but declined during the second and third years in response to declines in rodent densities. In contrast, invertebrate consumption was highest during the third year of the study and actually exceeded that of rodents.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, grassland, herbivores, consumption rates, herbivores,consumption rates, proceeding, proceedings}, url = {NMSU, Branson Library, S401 In85p 14th 1981}, author = {Pieper, Rex D.}, editor = {Alistair Smith and V.W. Hays} } @mastersthesis {52101, title = {Creosotebush seed production and viability following herbicide treatment}, year = {1980}, note = {//NMSU//NONE//}, month = {1980}, pages = {49}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {The flower, green and mature schizocarp (fruit) production, and germination responses of creosotebush (Larrea tridentata (DC) Cov.) treated with four levels of three different herbicides were evaluated in this study. Additional data analyzed included herbivory on mature schizocarps and from other studies being conducted on the study site creosotebush mortality. This research was undertaken to assess the effect of low levels of herbicide, 0.28, 0.56 and 0.84 kilogram per hectare on creosotebush seed viability and fruit production. It asserts that if creosotebush were not totally removed, it could increase in density due to herbicide response or reinfest areas where herbicides have been used. Herbicide levels were found to differ significantly throughout this study, with the exception of the herbivory data. Flower, green and mature schizocarp productions were negatively correlated and creosotebush germination and death were positively correlated to herbicide levels. In this study, creosotebush demonstrated significantly progressive increases in seed viability for the 0.00, 0.28 and 0.56 kilogram per hectare herbicide level.}, keywords = {brush control, herbicide, brush control, Larrea, dissertation, dissertations, herbicide,Larrea, Larrea,herbicide treatment, seed success, Larrea,seed production, Larrea,seed viability, theses, thesis}, author = {Stewat C. Sanderson} } @inbook {52104, title = {Carbon dioxide exchange of Yucca elata Engelm: Effect of temperature on photosynthesis and root respiration}, booktitle = {Yucca}, year = {1980}, month = {1980}, pages = {35-50}, publisher = {Centro de Investigacion en Quimica Aplicada}, organization = {Centro de Investigacion en Quimica Aplicada}, address = {Saltillo, Coahuaca, Mexico}, keywords = {carbon dioxide exchange, photosynthesis, root respiration, Yucca elata Engelm}, author = {Sisson, W.B.} } @proceedings {52108, title = {Control of erosion and sedimentation by treatment of arid rangeland}, year = {1980}, month = {1980}, pages = {177-192}, abstract = {

The number one pollutant of the waters in the United States, by volume, \ is sediment. Annual sediment deposition is estimated at 10,489 x 105 m3.\  Rangeland treatments such as vegetation manipulation by mechanical and chemical treatments are \ ways of controlling and regulating surface runoff, reducing sediments and increasing water quality. The presence of vegetation can affect infiltration by reducing the direct impact of raindrops on the soil surface which reduces erosion and sediment loads.

Studies have shown that several factors can affect water yield and sediment production such as\  storm intensity, watershed size, and soil surface microrelief. Other important factors are soil depth and water storage capacity, rainfall amount and distribution, infiltration rates, and the type of vegetation, before and after site conversion.

Measurements of soil surface characteristics indicate a significant reduction in surface runoff with increased amounts of erosion pavements. Mechanical treatment is important in converting rangeland infested with shrubs to grass and is a prime consideration in controlling runoff and erosion and, reducing sediments. Ripping and seeding an area to grass and browse species reduced runoff by 97 and 83 percent the first and third years following treatment.

Also erosion was reduced 86 percent and 30 percent, the first and third years, after the ripping treatment. Contour furrowing retains water at onsite locations and significantly reduces surface runoff. Pitting significantly reduced runoff when compared to a \ control treatment. No significant differences were noted between pitting and rootplowing treatments. Additional detention storage is provided by pitting and rootplowing treatments although smoothing of the soil surface with time was very apparent for both treatments. Infiltration increased and subsequently runoff and erosion decreased after approximately four years following \ rootplow and seeding treatments

}, url = {/files/bibliography/188.pdf}, author = {J.M. Tromble and Wood, M. K.} } @proceedings {52114, title = {Conference Proceedings}, year = {1980}, note = { //NMSU//NONE//ProCite field[2]: Arthropods and detritus decomposition in desert ecosystemsProCite field[6]: In}, month = {July 29 - August}, pages = {770-778}, publisher = {Office of Pesticide and Toxic Substances, Environmental Protection Agency}, address = {Syracuse, New York}, abstract = { Studies of the soil fauna of the worlds\&$\#$39; deserts are limited (Wallwork, 1970, 1972; Wood, 1971; Freckman, Mankau, and Ferris, 1975) and there have been no quantitative studies of the role of soil fauna in decomposition and nutrient release from plant litter. In 1977 we initiated a series of studies to examine the roles of various taxa of desert soil fauna in decomposition and in mineral release processes. In this paper we review selected portions of these studies in order to illustrate the relationships of termites, microarthropods, nematodes and soil microflora in litter decomposition in North American desert ecosystems.}, keywords = {abstract, abstracts, arthropod, decomposition, litter, conference, conference proceedings, conferences, decomposition, litter, microarthropods, decomposition, litter, nematodes, decomposition, litter, soil microflora, decomposition, litter, termites, detritus decomposition, SEE , microarthropod, decomposition, nematode,decomposition, pesticide, Chlordane, proceeding, proceedings, soil microflora,decomposition, termite, decomposition}, author = {Walter G. Whitford and Perseu F. Santos}, editor = {Dindal, Daniel L. (ed.)} } @proceedings {52133, title = {Carbon dioxide exchange of Yucca elata Engelm: effect of temperature on photosynthesis and root respiration}, year = {1979}, month = {1979}, address = {Saltillo, Coahuaca, Mexico}, keywords = {carbon dioxide exchange, photosynthesis, root respiration, Yucca elata Engelm}, author = {Sisson, W.B.} } @article {52156, title = {Critical thermal limits of desert honey ants: possible ecological implications}, journal = {Physiological Zoology}, volume = {51}, year = {1978}, note = {//NMSU//US-IBP//}, month = {1978}, pages = {206-213}, abstract = {

Critical thermal maxima (CTMAX) and minima (CTMIN), approximate upper and lower lethal temperatures, and the temperature limits of activity were determined for workers of diurnal and nocturnal species of Myrmecocystus. The CTMIN of diurnal species were between 11.2 and 12.0 C, and that of the nocturnal species was -0.4 C. All species had CTMAX between 43.3 and 48.4 C. Lower lethal temperatures of individuals of all species exposed for 2 h were below -5 C, and upper lethal temperatures were between 40 and 45 C. Diurnal species were active at 13-46 C air temperature (Ta) and 13-60 C soil surface temperature (Ts), and the nocturnal species was active at Ta and Ts of 2-30 C.

}, keywords = {ant, honey ants, ant, Myrmecocystus, thermal limits, article, articles, invertebrate, SEE , journal, journals, Myrmecocystus, thermal limits}, url = {files/bibliography/78-physzool-Whitford.pdf}, author = {Carol Ann Kay and Walter G. Whitford} } @article {52163, title = {Crossbreeding Hereford and Brangus cattle in varied southwestern environments}, year = {1978}, note = {//NMSU//NONE//}, month = {1978}, pages = {20}, institution = {New Mexico Agricultural Experiment Station}, type = {pp}, address = {Las Cruces, New Mexico}, abstract = {This bulletin reports the results of a study concerning crossbreeding Hereford and Brangus cattle in semidesert and mountain-foothills ranch environments in southern New Mexico. Objectives of the research were to compare weaning weights and feeder grades of calves, and the percentages of calves born and weaned from mating of Hereford x Hereford, Hereford x Brangus, Brangus x Hereford, and Brangus x Brangus cattle at two ranches. The effects of breed of sire, breed of dam, ranch, year, heterosis, and genotype-environment interaction were examined. Another objective was to compare the feedlot performance and carcass characteristics of the steer progeny of these matings and to study the same sources of variation in the analyses.}, keywords = {book, books, cattle, breeding, cattle, productivity, chapter, chapters, manangement, cattle, report, reports}, isbn = {Bulletin 661}, author = {B. J. Rankin and Shaffer, S. M. and Steven Paul Neville and Holland, L.A.} } @article {52189, title = {Climatic Guide, Las Cruces, 1851-1976}, year = {1977}, note = {//LOCAL//NONE//}, month = {1977}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, chapter, chapters, climate guide, evaporation, history, climate, precipitation, relative humidity, report, reports, solar radiation, temperature, air, temperature, soil, wind}, isbn = {Research Report 350}, author = {Malm, Norman R. and Houghton, Frank E.} } @article {52216, title = {Carbon reduction pathways and standing crop in three Chihuahuan desert plant communities}, journal = {The Southwestern Naturalist}, volume = {21}, number = {3}, year = {1976}, note = {//NMSU//US-IBP//}, month = {1976}, pages = {311-320}, abstract = {The complete floras of three Chihuahuan desert plant communities were surveyed to determine the relative numbers of species that possess either the C3, C4 or CAM carbon reduction pathway. There were more C3 species in all three communities. Spring-flowering species were predominantly C3 and CAM; C4 species most commonly flowered in the summer. Plant standing crop data were used as an indication of the contribution of each pathway to the primary production of the communities. In the most geographically widespread of the three communities, an alluvial plain, CAM plants contributed 48\% of the total biomass while only representing 10\% of the possible species present. Less than 1\% of the biomass was contributed by C4 species although they comprised 24\% of the possible species present. The C4 pathway did make a substantial standing crop contribution in a very localized community, an ephemeral desert lake bottom, where one C4 grass species accounted for 90\% of the biomass present.}, keywords = {article, articles, carbon reduction pathway, journal, journals, list, photosynthesis pathways, photosynthesis, pathways, plant community, carbon reduction pathways, plant community, standing crop}, author = {J. P. Syvertsen and Nickell, G. L. and Spellenberg, R. W. and Gary L. Cunningham} } @article {52222, title = {Changes in O2 consumption, body water and lipid in burrowed desert juvenile anurans}, journal = {Herpetologica}, volume = {32}, number = {1}, year = {1976}, note = {//NMSU//US-IBP//}, month = {1976}, pages = {23-25}, abstract = {

Juvenile Scaphiopus hammondi, Bufo debilis and Bufo cognatus (1-6 weeks post-metamorphosis) were allowed to burrow in soil containers in an environment chamber adjusted to simulate soil temperature conditions in the field. Approximately 50\% of the S. hammondi survived 6 months during which time body H2O changed from 86\% to 75\% and body lipid from 3.2\% to 2.0\%. Bufo cognatus did not burrow and died within 1 month. Bufo debilis made shallow burrows after the soil was mechanically broken and survived 3 months. O2 consumption of burrowed juvenile S. hammondi was 25\% of nonburrowed. O2 consumption of S. hammondi and the bufonid juveniles was higher than that of adults proportionate to the body size differences.

}, keywords = {amphibian, physiology, anuran, physiology, article, articles, journal, journals}, url = {files/bibliography/76-Hptlg-Whitford.pdf}, author = {Walter G. Whitford and Kenneth H. Meltzer} } @article {52221, title = {Comparative ecology of the harvester ants Pogonomyrmex barbatus (F. Smith) and Pogonomyrmex rugosus (Emery)}, journal = {Insectes Sociaux}, volume = {23}, number = {2}, year = {1976}, note = {//NMSU//US-IBP//}, month = {1976}, pages = {117-132}, abstract = {

Factors affecting local geographic distribution, foraging behavior and activity, forage selection, numbers of foragers per colony, nest spacing and nest structure of Pogonomyrmex rugosus and Pogonomyrmex barbatus were studied. There were seasonal differences in foraging activity. P. barbatus was more active in early summer and foraged at night while P. rugosus was more active in mid-summer foraging at night during July. Both species exhibited forage preference for grass seeds but took a variety of other materials. Where both species inhabited the same area they had an index of overlap for forage of 0.7. The colonies of both species were randomly distributed. Colony density was approximately 20 per hectare in areas supporting one or both species. There was no evidence of intraspecific aggression and foraging areas of colonies of the same species overlapped considerably. P. barbatus and P. rugosus avoid competition by habitat selection. Interspecific aggression probably accounts for the lack of overlap in local distribution.

}, keywords = {ant, distribution,Pogonomyrmex, ant,comparative ecology, ant,foraging behavior,Pogonomyrmex, article, articles, foraging,Pogonomyrmex, journal, journals, Pogonomyrmex,comparative ecology}, url = {files/bibliography/76-Insectes Sociaux-Whitford.pdf}, author = {Walter G. Whitford and P. Johnson and Ramirez, John} } @article {52231, title = {Causes of soil boundaries in an arid region: II. Dissection, moisture and faunal activity}, journal = {Soil Science Society of America Proceedings}, volume = {39}, year = {1975}, note = {//LOCAL//NONE//}, month = {1975}, pages = {324-330}, abstract = {Studies of soils in arid regions show similar boundaries between many soils. This paper illustrates some of the boundaries caused by differences in landscape dissection, soil moisture, and faunal activity. Some of the boundaries are apparent at the land surface and others are not. In dissected terrains a change from Argids to Orthids has been caused by slow, long-continued soil truncation associated with the dissection. The boundary occurs as a gradual, lateral change from a noncalcareous, reddish-brown, and red argillic horizon to a calcareous, brown cambic horizon. Differences in moisture movement in the past have caused soil differences resulting in boundaries between Typic Haplargids and Petrocalcic Paleargids. During Pleistocene pluvials, soil moisture moved deeply into reddish-brown pipes (preventing carbonate accumulation) but not in adjacent petrocalcic horizons. Typic Haplargids occur in the pipes whereas Petocalcic Paleargids occur adjacent to the pipes. Soil boundaries have also been caused by differences in moisture movement at present. Runoff from fan-piedmonts increases vegetation and organic carbon in and along margins of basin floors. This and associated increases in clay commonly result in a boundary between Typic Haplargids on the fan-piedmont and Ustollic Haplargids on the basin floors and adjacent toeslopes. In places, soil fauna have obliterated argillic horizons by mixing A and B horizons. This causes a boundary between Argids and Orthids.}, keywords = {article, articles, geomorphology, also SEE , journal, journals, soil, argillic horizon, soil, boundaries, soil, calcic horizon, soil, cambic horizon, soil, classification, soil, petrocalcic horizon}, author = {L. H. Gile} } @article {52246, title = {Cattle diets on semidesert grassland: botanical composition}, journal = {Journal of Range Management}, volume = {28}, year = {1975}, note = {//NMSU//NONE//}, month = {1975}, pages = {89-93}, abstract = {Botanical composition of cattle diets on semidesert rangeland was studied by microhistological techniques. Cattle consumed 56\% of all species available.... Composition of diets changed with seasons.... Perennial grasses represented dependable sources of forage, but never comprised more than 50\% of the steers{\textquoteright} diets in any season.... Shrub portions were highest in spring when soaptree yucca was grazed almost exclusively. Forb fractions of diets varied little among seasons but were highest in winter.}, keywords = {article, articles, cattle grazing,diet, cattle, esophageal-fistulated, cattle,diet, diet,cattle, journal, journals}, author = {R. E. Rosiere and Reldon F. Beck and Wallace, J.D.} } @article {52245, title = {Cattle diets on semidesert grassland: nutritive content}, journal = {Journal of Range Management}, volume = {28}, number = {2}, year = {1975}, note = {//NMSU//NONE//}, month = {1975}, pages = {94-96}, abstract = {A study of chemical composition and organic matter digestibility of cattle diets was conducted on semidesert grassland in southern New Mexico during different seasons. Forage quality was highest in the spring. Fall diets were lower in digestibility energy. Level of protein in fall diets was greater than requirements for dry cows but was less than recommended levels for lactating cows or growing calves. A stepwise regression equation showed that protein accounted for more variation in in vitro digestibility than did other components.}, keywords = {article, articles, bioenergetics,cattle, cattle diet,protein, cattle grazing,nutrition, cattle,diet, cattle,esophageal-fistulated, cattle,nutrition, journal, journals, nutrition,cattle}, author = {R. E. Rosiere and Reldon F. Beck and Wallace, J.D.} } @mastersthesis {52251, title = {A comparison between photointerpretation and field vegetation mapping methods on the Jornada Experimental Range}, year = {1975}, note = {//USDA//NONE//}, month = {1975}, pages = {47}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {A study was performed with the objective of observing differences between the photointerpretation and the field vegetation mapping procedure.... Differences in detail of delineating vegetation units were also found between the two mapping procedures. The field method showed more generalized mapping while the photointerpretation method showed more detailed mapping of boundaries between vegetation units.}, keywords = {community, vegetation mapping, dissertation, dissertations, mapping, field vegetation mapping, mapping, photointerpretation, photointerpretation, vegetation mapping, technique, photointerpretation, technique,vegetation mapping, theses, thesis, vegetation mapping, methods, vegetation mapping, photointerpretation}, author = {Vasquez-Aldape, Ricardo} } @article {52258, title = {Comparative ecology of the harvester ants Pogonomyrmex barbatus (F. Smith) and Pogonomyrmex rugosus (Emery)}, year = {1975}, note = {//??//US-IBP//}, month = {1975}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {ant,harvester, book, books, chapter, chapters, pogonomyrmex, report, reports}, isbn = {Research Memorandum 75-28}, author = {Walter G. Whitford and P. Johnson and Ramirez, John} } @article {52262, title = {Competitive relationships of the Common and Lesser Nighthawks}, journal = {The Condor}, volume = {76}, number = {1}, year = {1974}, note = {//USDA//NONE//}, month = {1974}, pages = {1-20}, abstract = {The study of competition and the resulting inferences, of necessity, have been often indirect. This is because the processes of competitions, as currently understood, are often quite ephemeral and subtle. On a basis of species interactions, there are three general situations for which competition often has been invoked as an explanation (Miller 1967): (1) the narrowing of a niche in sympatry (Lack 1944); (2) contiguous allopatry in the absences of environmental discontinuity (Miller 1964); and (3) character displacement (Brown and Wilson 1956; Hutchinson 1957; Mayr 1963). If these situations do indeed develop as a result of competition, then under certain circumstances their maintenance could require continuing competitive interactions. Thus such situations should provide the opportunity to study competition as a dynamic and vital process. Recent examples of studies performed under these conditions include Willis (1966), Brown (1971), Heller (1971), and Sheppard (1971). The distribution (fig. 1) and habitat relationships of the Common Nighthawk (Chordeiles minor) and the Lesser Nighthawk (C. acutipennis) are favorable for the study of factors involved with the competitive interactions of ecologically similar species. The two species are very similar in size, appearance, and general habits. The allopatric ranges of both species include habitats similar to those within the sympatric region. This combination provides a means of evaluating the impact of sympatry on the breadth of habitat utilization of both species. In addition, at several localities within the sympatric distribution, the habitat isolation breaks down, providing the means to study directly the competitive interactions between these species.}, keywords = {article, articles, Aves, Chordeiles, bird, also SEE , bird, Common Nighthawk, bird, competition, bird, diet, bird, Lesser Nighthawk, bird,distribution, journal, journals}, author = {Caccamise, Donald F.} } @mastersthesis {52263, title = {Comparative breeding ecology of the Western Kingbird (Tyrannus verticalis) in three habitat types}, year = {1974}, note = {//LOCAL//NONE//}, month = {1974}, pages = {39}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Breeding ecology of the Western Kingbird (Tyrannus verticalis) in a riparian habitat and an urban habitat was compared to that in a Chihuahuan Desert site during the summer of 1973 in southern New Mexico. Emphasis was placed upon the populations{\textquoteright} evironmental responses to differences in climate, food, and predation. These environmental responses were expressed as differences in length and timing of breeding season; breeding density; fledgling frequency; nest-success frequency; and fledglings per clutch, per pair, per hectare. Evidence indicates that the overall productivity of the desert population was reduced by the direct effect of a greater degree of climatic exposure, scarcity of food, and relatively greater vulnerability to predation. Among the ecological responses observed in the desert population were (1) an intermediate breeding season, (2) the lowest breeding density, (3) the highest fledgling frequency, (4) the lowest nest-success frequency, and (5) the lowest number of fledglings per clutch, per pair, per hectare.}, keywords = {bird, habitat, bird, Tyrannus verticalis, bird, Western Kingbird, breeding ecology,Western Kingbird, dissertation, dissertations, theses, thesis, Western Kingbird,breeding ecology}, author = {Cuesta, Lorenzo Rafael} } @conference {52270, title = {Cleaner air with chemical control of mesquite}, booktitle = {Weed Science Society of America Conference}, year = {1974}, month = {1974}, pages = {No. 63}, keywords = {chemical control, mesquite}, author = {W. L. Gould and C.H. Herbel} } @mastersthesis {52283, title = {Community process and structure}, year = {1974}, note = {//NMSU,USDA//US-IBP//}, month = {1974}, pages = {91}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {(1) This thesis presents three papers on community ecology. Preceding these, in the first chapter, is a review of current ecology.... The subsequent chapters consider (a) whether communities have properties (in Chapter II), (b) structure and diversity and its causes (in Chapter III) and (c) community stability (in Chapter IV).}, keywords = {bird community, community ecology, structure and process, dissertation, dissertations, model, bird communities, model,predator-prey, theses, thesis}, author = {Stuart L. Pimm} } @mastersthesis {52284, title = {A comparative modelling study of plant growth systems in a desert ecosystem}, year = {1974}, note = {//NMSU//NONE//}, month = {1974}, pages = {68}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {The use of modeling as a tool in ecosystem analysis has mushroomed in recent years.... Two possible modeling approaches are within quantitative and a qualitative formats. The quantitative approach in ecology usually incorporates the level-rate paradigm of Forrester, utilizing systems of differential equations to describe component relationships. A high level of model precision is one of the objectives. The qualitative approach, as used here, incorporated the pulse-reserve paradigm of Bridges, utilizing blocks of logic statements to test for the presence or absence of specific driving variables. A high level of model realism is one of the goals using this technique. Although void of functional relationships or mechanisms, the pulse-reserve model did offer long-term stability. The reserve-trigger-pulse sequence of the model is biologically real and represents an adaptive strategy for organisms in arid environments. The possibility of expanding this approach for and entire system is discussed. A model is proposed that incorporates the more precise level-rate formulation for primary producers and the pulse-reserve paradigm for higher trophic levels.}, keywords = {dissertation, dissertations, model, level-rate, model, pulse-reserve, model,comparative, model,plant growth, plant growth system,model, productivity,model, theses, thesis}, author = {J. F. Reynolds} } @article {52294, title = {Comparative investigations in the U.S. IBP Grassland Biome: decomposition section}, year = {1973}, note = {//USDA//US-IBP//}, month = {1973}, institution = {Colorado State University}, address = {Ft. Collins, Colorado}, keywords = {book, books, chapter, chapters, decomposition,grassland, report, reports}, isbn = {Technical Report 210}, author = {Coleman, D. C.} } @article {52297, title = {Critical thermal maxima in several life history stages in desert and montane populations of Ambystoma tigrinum}, journal = {Herpetologica}, volume = {29}, number = {4}, year = {1973}, note = {//LOCAL//NONE//}, month = {1973}, pages = {352-355}, abstract = {

Montane neotenic Ambystoma tigrinum had lower critical thermal maxima (CTM) than desert neotenic A. tigrinum. In all other life history stages studied there were no differences in CTM between montane and desert populations. Comparison of life history stages in a desert population showed that larvae and neotenic adults had higher CTM than transformed animals or animals in the process of transforming. The CTM differences on life history stages reflects the potential thermal stresses to which these stages may be subject.

}, keywords = {Ambystoma, life history, Ambystoma, physiology, amphibian, Ambystoma, article, articles, journal, journals}, url = {files/bibliography/73-Herp-Whitford.pdf}, author = {Jeff Delson and Walter G. Whitford} } @mastersthesis {52312, title = {Carcass performance of Brangus, Hereford and reciprocally crossbred steers}, year = {1973}, note = {//NMSU//NONE//}, month = {1973}, pages = {43}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Four breeding groups of purebred Brangus, Hereford and their reciprocal crosses raised at the New Mexico State University College Ranch and the Fort Stanton Experimental Range were evaluated for carcass characteristics.... Correlations among various live and carcass traits were calculated. As would be expected, quality grade and marbling were highly correlated. Slaughter weight was moderately related to weaning weight and average daily gain. Carcass weight per day of age was moderately related to average daily gain, weaning weight and slaughter weight. Significant correlations of rib eye area with slaughter weight and conformation were apparent. Cutability and yield grade were both strongly related to adjusted fat thickness along with moderate relationships to rib eye area and internal fat. Lean cuts per day of age was highly related to carcass weight per day of age and was moderately related to average daily gain, slaughter weight and rib eye area.}, keywords = {cattle, carcass performance, cattle,breeding, dissertation, dissertations, theses, thesis}, author = {Steven Paul Neville} } @mastersthesis {52313, title = {Cattle diets on semidesert grassland}, year = {1973}, note = {//NMSU//NONE//}, month = {1973}, pages = {139}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Botanical and nutritive composition of cattle diets on semidesert grassland was evaluated. Four esophageal-fistulated steers were used to collect forage during five seasons. The study was conducted on three seasonal suitability pastures and one year-long use pasture in southern New Mexico. It was found that excessive numbers of steers would be needed to adequately sample for dietary lignin. Sampling for other nutrient components and digestibility required six to eight steers.}, keywords = {cattle grazing,diet, cattle management, cattle, esophageal-fistulated, cattle, nutrition, cattle,diet, diet,cattle, dissertation, dissertations, theses, thesis}, author = {R. E. Rosiere} } @article {52324, title = {Combat in the horned lizard, Phrynosoma cornutum}, journal = {Herpetologica}, volume = {29}, number = {2}, year = {1973}, note = {//NMSU//US-IBP//}, month = {1973}, pages = {191-192}, abstract = {

Mark-recapture data on Phrynosoma cornutum from the Desert Biome Jornada Validation Sites since 1970 and our feeding behavior studies support the contention that these animals are not territorial. Individual lizards, followed for a day, have moved well over 100 meters and frequently approach within a meter of another P. cornutum. This type of encounter usually results in head bobbing and mutual retreat of the lizards. On 19 July 1972 the senior author observed physical combat between two male P. cornutum, hereafter designated A and B. The combat was not preceded by head bobbing display by either lizard and lasted for over an hour [(0851-1005 hours) mountain daylight time]... A detailed description of the combat follows.... To our knowledge this is the only report of combat in Phrynosoma although vigorous combat is common in inguanids.

}, keywords = {article, articles, behavior, Phrynosoma, journal, journals, Phrynosoma, behavior}, url = {files/bibliography/73-Herpetologica-Whitford.pdf}, author = {Whitford, W. Brett and Walter G. Whitford} } @mastersthesis {52334, title = {Comparative niche utilization by two species of kangaroo rats (Genus Dipodomys)}, year = {1972}, note = {//??//NONE//}, month = {1972}, pages = {71}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {Aspects of the niche requirements of Dipodomys merriami and Dipodomys ordii in southern New Mexico were compared. The parameters investigated included habitat, diet, microenvironment and comparative physiology.D. merriami inhabited rockier sites than D. ordii, and had burrows that were both shallower and simpler than those of D. ordii. A comparison of burrow microclimate revealed that the burrows of D. ordii were significantly more humid in the summer than were those of D. merriami, and that the maximum temperature in D. ordii burrows was lower than that in burrows of D. merriami. A comparison of the diets of these animals, based on the weight per cent, and a synthetic importance value for each food item showed that while there was some dietary overlap, the diets of these two species were quite different. A comparison of the evaporative water loss and metabolism showed that D. ordii was less tolerant to high heat than D. merriami. D. merriami eliminated excessive heat loads by smearing its body with saliva and evaporating its saliva. D. ordii was not observed to eliminate excess body heat in this way.D. merriami was found to have a higher metabolic rate at low temperatures than did D. ordii, as well as less tolerance to cold, which suggests that the physiological characteristics of these species are important factors affecting their overall distribution. It was concluded that these species were well separated ecologically, and that there was little or no reason to consider them to be competing with one another.}, keywords = {Dipodomys,diet, Dipodomys,habitat, Dipodomys,niche utilization, Dipodomys,physiology, dissertation, dissertations, kangaroo rat, SEE , rodent, Dipodomys, rodent, kangaroo rat, Dipodomys, theses, thesis}, author = {Gaby, Ronald} } @article {52352, title = {Computer processing of chart quadrat maps and their use in plant demographic studies}, journal = {Journal of Range Management}, volume = {25}, number = {6}, year = {1972}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {November 1, 1972}, pages = {476-478}, abstract = {Chart quadrat maps offer a unique source of data on long-term trends in grasslands. Through the use of film-scanning computer systems, this information can be more easily processed and used in plant demographic studies. There is a large and varied assemblage of data that has been collected over the years on the semiarid grasslands information that can be valuable in studying today{\textquoteright}s important natural resource management problems. To a large extent, however, much of this information has not been sufficiently utilized because of the time involved in the effort. One such source of data of this type is that available from chart quadrat mappings. This paper presents a method which enables one to more easily quantify and use the information on chart quadrat maps and some examples of how these data can be used in plant demographic work.}, keywords = {chart quadrat maps, film-scanning computer systems, grassland trends, plant demographic studies}, url = {/files/bibliography/137.pdf}, author = {R. G. Wright} } @mastersthesis {52357, title = {Competitive relationships of the Common and Lesser nighthawk}, year = {1971}, note = {//USDA//NONE//}, month = {1971}, pages = {79}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {Competitive relationships and mechanisms for the maintenance of habitat displacement were investigated in the Common Nighthawk (Chordeilesminor) and the Lesser Nighthawk (C. acutipennis) by studying habitat distributions, behavioral interactions, flight mechanisms and food habitats. A one-way habitat displacement results from the exclusion of C. minor from desert habitats occupied by C. acutipennis. Specific adaptations contribute to the competitive superiority of C. acutipennis in desert habitats; these include lack of pronounced territoriality, a slow maneuverable flight pattern, little aggressiveness, and the propensity for wandering great distances in search of food and water. C. minor is highly territorial, is capable of two distinct flight speeds, is highly aggressive, and generally feeds within territory boundaries. Analyses of stomach contents indicated much overlap between the species and similar levels of specialization; however, when, by inference, food became limiting the diet of C. minor became increasingly generalized while diet overlap declined. Arguments are presented to show that C. minor is best adapted to conditions where food is seldom limiting, while C. acutipennis is adapted to conditions where food resources may often be of low density and/or highly dispersed. Evidence indicates that aggressiveness may act to prevent co-occurance of the species in mutually suitable habitats. These aggressive interactions appeared to function in the form of aggressive neglect. In areas of co-occurrence the more aggressive and dominant C. minor spends a considerable amount of time excluding C. acutipennis from its territory. It is suggested that this time and energy is of sufficient magnitude to place C. minor at a competitive disadvantage in areas of co-occurence with C. acutipennis.}, keywords = {Aves, Chordeiles, bird, Common Nighthawk, bird, competition, bird, diet, bird, Lesser Nighthawk, bird,distribution, dissertation, dissertations, theses, thesis}, author = {Caccamise, Donald F.} } @article {52361, title = {Comparative temperature and moisture responses in Gambel and Scaled Quail}, journal = {The Condor}, volume = {73}, year = {1971}, note = {//LOCAL//NONE//}, month = {1971}, pages = {430-436}, abstract = {Gambel Quail (Lophortyx gambelii) range throughout the desert areas of the extreme southwestern United States and northern Mexico, while Scaled Quail (Callipepla squamata) generally inhabit the more mesic semiarid grass plains of the Southwest and much of Mexico. The ranges of the two species overlap in southeastern Arizona and southwestern New Mexico (A.O.U. 1957; Leopold 1959). The habitats of theses species are similar in the area of sympatry. The species are also similar in general body size, food habits, and in other parameters of their ecology. Comparative data relating to temperature and water relations would appear to be valuable in understanding these sympatric and closely related species. These data are also important in understanding adaptations of birds to hot, arid climates.}, keywords = {article, articles, Aves, Callipepla, Aves, Lophortyx, bird, Gambel Quail, metabolism, bird, physiology, bird, Scaled Quail, metabolism, journal, journals}, author = {Carl W. Henderson} } @article {52383, title = {Critical requirements for genetic expression of verticillium wilt tolerance in acala cotton}, journal = {Phytopathology}, volume = {60}, number = {3}, year = {1970}, month = {March 1970}, pages = {559-560}, keywords = {acala, cotton, verticillium}, url = {/files/bibliography/99-004.pdf}, author = {J.R. Barrow} } @mastersthesis {52385, title = {Comparative production of Larrea divaricata Cav. on three geomorphic surfaces in southern New Mexico}, year = {1970}, note = {//LOCAL//NONE//}, month = {1970}, pages = {40}, school = {New Mexico State University}, type = {Ph.D. Dissertationspp}, address = {Las Cruces, New Mexico}, abstract = {Net above ground productivity was measured for 3 years on creosotebush (Larrea divaricata Cav.) occurring on three geomorphic surfaces which differed in age and profile characteristics. Rates of stem elongation, fruit production, flower production, and accumulation of secondary wood were ascertained for each of the geomorphic surfaces. Growth rates varied among plants of the different surfaces, but when the net production of stands on each surface were compared the surfaces were remarkably similar. Statistically significant differences were present in both growth and net productivity between years. Creosotebush seems to have a great capacity for adjusting to sites of broad ecological amplitude with no apparent effect upon its ability to fix energy.}, keywords = {dissertation, dissertations, geomorphology,Larrea, Larrea,geomorphology, Larrea,phenology, Larrea,productivity, phenology,Larrea, productivity,Larrea, theses, thesis}, author = {J. H. Burk} } @article {52390, title = {Comparisons of small mammal biomass at eight U.S. IBP Grassland Biome Research Sites, 1970 season}, year = {1970}, note = {//??//US-IBP//}, month = {1970}, institution = {Colorado State University}, address = {Ft. Collins, Colorado}, keywords = {book, books, chapter, chapters, report, reports, rodent,biomass}, isbn = {Abstracts}, author = {Grant, W. E.} } @article {52393, title = {Comprehensive network site description, Jornada}, year = {1970}, month = {1970}, pages = {23}, institution = {Colorado State University}, address = {Ft. Collins, CO}, abstract = {The Jornada Experimental Range was withdrawn from the Public Lands for research in 1912 by presidential proclamation. From 1915 until 1953, it was under jurisdiction of the U.S. Forest Service. Following realignment of range research activities within the Department of Agriculture in 1953, the range was transferred to the Agricultural Research Service. Since 1953, the Jornada has been operated by the Arid Pasture and Range Sections, Crops Research Division, of ARS.}, keywords = {government publication, Jornada Experimental Range, site description}, url = {/files/bibliography/126.pdf}, author = {C.H. Herbel and Pieper, Rex D.} } @proceedings {52394, title = {Control of mesquite, creosotebush, and tarbush on arid rangelands of the southwestern United States}, year = {1970}, month = {1970}, pages = {38-41}, address = {Surfers Paradise, Australia}, abstract = {Sparse stands, up to 200 plants per ha, of mesquite, creosote bush and tarbush may be economically controlled with an individual plant treatment of fenuron pellets or other dry herbicides. Aerial spraying with 2, 4, 5-T is also an economical method of reclaiming mesquite-infested areas. The treatment also affords an excellent method of increasing production of perennial grasses.}, keywords = {aerial spraying, arid rangelands, control, creosotebush, fenuron pellets, mesquite, tarbush}, url = {/files/bibliography/125.pdf}, author = {C.H. Herbel and W. L. Gould} } @article {52397, title = {Chemical composition of forage species grazed by cattle on an arid New Mexico range}, year = {1970}, month = {1970}, pages = {33 }, abstract = {Range beef cattle performance depends greatly upon the level of nutrients in the forage consumed. Chemical composition indicates the nutritive value of plants, although the composition varies because of such factors as stage of plant maturity. Watkins reported chemical composition of several grasses on the New Mexico State University ranch (20 miles north of Las Cruces), by month of harvest, which reflected stage of maturity. Samples of grasses were clipped at specified heights above the ground in exclosures which}, keywords = {chemical composition, forage species, government publication, range cattle}, url = {/files/bibliography/127.pdf}, author = {Nelson, A.B. and C.H. Herbel and Jackson, H.M.} } @article {52400, title = {Creosotebush control with phenoxy herbicides, picloram, and fuel oil in southern New Mexico}, year = {1970}, note = {//USDA//NONE//}, month = {1970}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, abstract = {Creosotebush was sprayed with various formulations of 2, 4-D and 2,4,5-T, and with picloram and fuel oil, using ground spray equipment, on the University{\textquoteright}s Agricultural Experiment Station ranch, from 1962 to 1966. Results of spraying regrowth of mowed creosotebush at different seasons varied with herbicide used. With 2,4,5-T ester, highest kills were obtained in late summer, and lowest kills were obtained in spring and fall. Early summer results were not significantly different from those of the other seasons. Picloram gave lowest kills in spring, highest kills in fall. The intermediate-level early and late summer kills did not differ significantly from either spring or fall kills. Fuel oil gave lowest kills in spring, highest kills in fall, and intermediate-level kills in early and late summer.}, keywords = {book, books, brush control, herbicide, brush control, Larrea, chapter, chapters, herbicide, "2,4,5-T", herbicide, "2,4-D", herbicide, fuel oil, herbicide, phenoxy, herbicide, picloram, Larrea, herbicide, management, also SEE , report, reports}, isbn = {Bulletin 554}, author = {Valentine, K. A.} } @conference {52411, title = {Chemical control of mesquite as influenced by rate of 2, 4, 5-T, carrier type, and volume and type of aircraft}, booktitle = {Annual Meeting, Weed Science Society of America}, year = {1969}, month = {1969}, pages = {No. 63}, keywords = {chemical control, mesquite}, author = {W. L. Gould and C.H. Herbel} } @article {52421, title = {Chemical composition of tobosa grass collected by hand-plucking and esophageal-fistulated steers}, journal = {Journal of Range Management}, volume = {22}, number = {3}, year = {1969}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {May 1, 1969}, pages = {155-159}, abstract = {Organic matter recovery of seven feeds collected through esophageal fistulae of three steers averaged 90.4\%. Six of the seven fistula samples contained significantly more ash than the feeds offered. Fistula samples of grazed tobosa [Hilaria mutica (Buckl.) Benth.] contained less A.O.A.C. fiber but more silica, ash, protein, ether extract, detergent fiber and detergent lignin than hand-plucked grass. Except for ash, the differences in chemical composition between hand-plucked and esophageal-fistula samples were apparently due to selectivity by the grazing steers. We assume that samples collected by means of an esophageal fistula are more nearly representative of the forage consumed by grazing steers than samples hand-plucked by a technician.}, keywords = {chemical composition, esophageal-fistulated steers, hand-plucking, tobosa}, url = {/files/bibliography/118.pdf}, author = {H.E. Kiesling and Nelson, A.B. and C.H. Herbel} } @proceedings {52424, title = {Chemical composition of the diet of cows grazing on arid range}, volume = {20}, year = {1969}, month = {1969}, pages = {355-360}, abstract = {Chemical composition of range plants offers an indication of their nutritive value. The protein content of forages usually decreases as plants mature. The levels of fiber and lignin are generally reflections of the availability of energy from the plant because, as plants grow and mature, the level of fiber and degree of lignification increase and the digestibility of these fibrous portions decreases. Several New Mexico studies (Watkins, 1943; Watkins and Repp, 1964; and others) have reported the chemical composition of range plants collected throughout the state. These reports concern forage species found in a pasture without emphasis on proportions or quantities of each species grazed by livestock. Also, sampling has not included many forbs, which may constitute a major portion of the diet of grazing cows. The objective of this study was to determine the chemical composition of the plant species grazed by cattle on an arid range in southern New Mexico.}, keywords = {arid range, cattle, chemical composition, diet, forage species}, url = {/files/bibliography/119.pdf}, author = {Nelson, A.B. and C.H. Herbel and Jackson, H.M.} } @mastersthesis {52446, title = {Comparative temperature and moisture responses in Gambel and Scaled Quail}, year = {1967}, note = {//LOCAL//NONE//}, month = {1967}, school = {New Mexico State University}, type = {M.S. Thesis}, address = {Las Cruces, New Mexico}, abstract = {Various responses to high temperature and low moisture were studied in the laboratory in Gambel Quail (Lophortyx gambelii) and Scaled Quail (Callipepla squamata). The minimum daily water requirements of the two species were not found to differ significantly at 28 degrees - 29 degrees Celsius. Evaporative water loss rates were similar at 25 degrees, 30 degrees, and 35 degrees Celsius. At ambient temperatures of 40 degrees and 45 degrees Celsius, Gambel Quail lost significantly higher percentages of water through evaporation than Scaled Quail. The response of body temperature to increasing ambient temperatures was, in general, the same for both species. Body temperatures indicated that thermoneutrality probably existed between 25 degrees and 35 degrees Celsius for both species. Both species were able to tolerate an ambient temperature of 40 degrees Celsius without ill effects, but at 45 degrees Celsius Gambel Quail survived better than Scaled Quail. Gambel Quail exhibited gular flutter when body temperature exceeded 43 degrees Celsius. Oxygen consumption values were similar at 30 degrees Celsius, but the value for Gambel Quail was significantly higher at 40 degrees Celsius. Scaled Quail were more efficient in heat dissipation at 30 degrees and 40 degrees Celsius. These results show that Gambel Quail are better adapted physiologically to hot, arid environments than are Scaled Quail. This is quite plausible since Gambel Quail inhabit extreme desert areas, and Scaled Quail are confined to more mesic areas with more moderate temperatures. Comparisons were made towhee results of other workers on California Quail.}, keywords = {Aves, Callipepla, Aves, Lophortyx, bird, Gambel Quail, metabolism, bird, physiology, bird, Scaled Quail, metabolism, dissertation, dissertations, theses, thesis}, author = {Carl W. Henderson} } @conference {52448, title = {Creating a more favorable microenvironment for seeding Southwestern ranges}, booktitle = {Agronomy Abstracts}, year = {1967}, month = {1967}, pages = {36}, keywords = {microenvironment, seeding, Southwestern ranges}, author = {C.H. Herbel} } @mastersthesis {52454, title = {Cover biomass and root-shoot habit of Larrea divaricata on a selected site in southern New Mexico}, year = {1967}, note = {//LOCAL//NONE//}, month = {1967}, school = {New Mexico State University}, type = {M.S. Thesis}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, Larrea,biomass, Larrea,root-shoot, theses, thesis}, author = {Singh, S. P.} } @article {52464, title = {Cambic and certain noncambic horizons in desert soils of southern New Mexico}, journal = {Soil Science Society of America Proceedings}, volume = {30}, year = {1966}, note = {//LOCAL//NONE//}, month = {1966}, pages = {773-781}, abstract = {In a study area of southern New Mexico, horizons in the B position may be ordered in degrees of increasing development, and form and essentially continuous series closely related to age. No evidence of soil development is found in freshly deposited arroyo alluvium. Next in the development scale are horizons with some weak evidence of soil formation, but which are still too weakly developed to qualify as cabic horizons. With increasing age, cambic horizons and finally argillic horizons occur in the B position. The relationships of soil development to age are confounded in some older soils by such factors as soils truncation and soil mixing. Distinct cambic horizons have formed in soils that are less than about 5,000 years old. In various cambric horizons there has been sufficient alteration of the original parent material to destroy fine strata, form structure, develop redder color, redistribute carbonate, and accumulate slight amounts of silicate clay. Cambic horizons of old, polygenetic soils show evidence of prefound change in the B position since deposition of the parent materials and the start of soil formation. Argillic horizons apparently formed in some soils and were alter destroyed. some soils once had much thicker B horizons than they now have. The present climate of this desert regions is arid, but evidence of former glaciation and lakes indicates a climatic change. The present climate is apparently warmer and drier than the climates of Pleistocene pluvials. Soils formed mainly in the Pleistocene tend to have thicker, stronger horizons than do soils formed in the Recent; this is apparently caused in part by the Pleistocene pluvial climates.}, keywords = {article, articles, geomorphology, classification, journal, journals, soil, argillic horizon, soil, cambic horizon, soil, classification, soil, genesis}, author = {L. H. Gile} } @article {52468, title = {Creosotebush (Larrea tridentata [DC.] Coville)}, year = {1966}, month = {1966}, pages = {21 }, publisher = {U.S. Department of Agriculture and U.S. Department of the Interior, Chemical Control of Range Weeds, Interagency Report}, abstract = {Creosotebush, a member of the caltrops family, is a common evergreen shrub usually 3 to 6 feet tall. It occurs on an estimated 461/2 million acres in the arid Southwest from California to western Texas. It spreads from seed. This plant is worthless for browsing. Desirable perennial grasses cannot compete with creosotebush. After creosotebush becomes established on a site, it can gain dominance rather rapidly. When this occurs, the entire site deteriorates from wind and water erosion. Individual plant treatment with fenuron pellets have consistently given plant kills in excess of 90 percent. Monuron powder, monuron-trichloroacetate benzoic acid granules have been less effective. An effective rate is an individual plant treatment of 1 gram active ingredient of 25 percent fenuron pellets (1 level teaspoon = 1 gram active ingredient) for each 1{\textonehalf} feet of canopy diameter. The pellets should be scattered around the base of the plant. Since fenuron is desensitized by light and high temperatures, it is important that the materials be applied just prior to or in the early part of an expected rainy season. This is an economical method of controlling sparse stands (up to 75 plants per acre) of creosotebush. It would be especially beneficial where creosotebush is invading grassland. The work reported was done on gravelly sandy loams in southern New Mexico.}, keywords = {creosotebush, description, government publication, Larrea tridentata, plant treatment}, url = {/files/bibliography/095.pdf}, author = {C.H. Herbel} } @mastersthesis {52479, title = {Chromic oxide in paper as an indicator in digestion trials with steers}, year = {1965}, note = {//??//NONE//}, month = {1965}, pages = {49}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {cattle,chromic oxide, cattle,digestion, chromic oxide, cattle digestion, dissertation, dissertations, theses, thesis}, author = {Green, Geary Ray} } @article {52489, title = {Chirothrips falsus on Black Grama Grass}, year = {1965}, note = {//NMSU//NONE//}, month = {1965}, institution = {New Mexico Agricultural Experiment Station}, abstract = {

This study was undertaken to determine the biology and ecology of Chirothrips falsus Priesner and its relationship to the typically poor seed set of black grama. The work was conducted on native range, principally at the University Ranch near Las Cruces, and on irrigated plots at the Middle Rio Grande Branch Station near Los Lunas. Tests showed that seed yields can be significantly increased by thrips control. SD 4402 (Telodrin) gave the best control and the greatest increase in seed yield, although dieldrin and Guthion gave good control and substantial seed increases. The granulated systemics, di-syston and phosphamidon, were significantly inferior to dieldrin spray for thrips control and the resulting seed increase of black and blue grama. A series of three spray applications of Bidrin at weekly intervals, begun shortly before the grass began to bloom, reduced thrips numbers and increased seed yields more effectively than similar schedules begun one and two weeks earlier.

}, keywords = {book, books, Bouteloua, Chirothrips, Bouteloua, seed germination, chapter, chapters, Chirothrips,life history, germination, Bouteloua, insect, Chirothrips, insect, thrips, insecticide, thrip control, plant, Bouteloua, insect association, report, reports, thrip, SEE }, isbn = {Bulletin 499}, author = {Watts, J. G.} } @article {52496, title = {A comparative study of soils of selected creosotebush sites in southern New Mexico}, journal = {Journal of Range Management}, volume = {17}, year = {1964}, note = {//USDA//NONE//}, month = {1964}, pages = {23-32}, abstract = {This paper presents the results of a study of physical and chemical properties of soils of four selected creosotebush sites in southern New Mexico. The soils remain capable of supporting establishment and growth of the climax dominant grasses, although deterioration through erosion, and in one case loss of structure, has occurred. One site appeared to have lost soil to the extent that production capacity for the test species had been significantly reduced. At the same site, continuing erosion threatened to further reduce soil productivity by exposure of an underlying high gypsum substratum. Range management practices consisting of proper grazing management and control of creosotebush to preserve and improve these range areas were strongly indicated.}, keywords = {article, articles, biochemistry, Larrea soils, grassland,Larrea, journal, journals, Larrea, biochemistry, Larrea, soils, soil,Larrea}, author = {Valentine, K. A. and Norris, J. J.} } @article {52509, title = {Cry alarm . . . killer loose . . . }, journal = {New Mexico Stockman}, volume = {29}, number = {4}, year = {1961}, month = {1961}, pages = {26-27}, abstract = {Attractive as it appears, cattle ranching may sometimes be likened to gambling against a stacked deck. Uncertain markets plague the budget; the inevitable and dreaded drought, ever lurking around the corner, brings setbacks, death losses, extra feed, labor costs, and many other extraordinary burdens. On the other hand, when welcome rain does finally come and the hills and valleys take on that beautiful green color, elation is tempered by knowing that "tares must grow with the wheat," specifically, poisonousweeds. At any time, the lovely green expanse is likely to be seen flecked with the bloated bodies of dead cattle. This is a sight calculated to take the joy out of life. An ironical twist of this play from the stacked deck lies in the calamity stemming from a totally unexpected source. It can and oftendoes happen; an analogy is the death-dealing plague of 1918. A virulent form of a disease thought to be relatively harmless, the terrible "flu" epidemic swept the world, claiming more victims than the world war just preceding. So too in the plant kingdom a variety of subjects, usually weeds ordinarily harmless, grazed and relished by livestock as good forage, will suddenly turn traitor. Chemical changes occurring under climatic or other conditions affecting plant growth can transform these weeds overnight into deadly killers. Another deal from the stacked deck--the plant known to be toxic but by its infrequent and scattered occurrence presents no immediate threat. Comes a severe drought or some other disturbing factor and the inhibitor is removed. The erstwhile harmless plant then burgeons into dense colonies, its very abundance enhancing the hazard a thousandfold. It is then taken in lethal quantities by cattle; result, severe losses by a "new" killer plant.}, keywords = {cattle ranching, chemical changes, disease, drought, poisonous weeds}, url = {/files/bibliography/083.pdf}, author = {F.N. Ares} } @article {52511, title = {A classification of ca horizons in soils of a desert region, Dona Ana County, New Mexico}, journal = {Soil Science Society of America Proceedings}, volume = {25}, year = {1961}, note = {//LOCAL//NONE//}, month = {1961}, pages = {52-61}, abstract = {A ca horizon is defined in the Soil Survey Manual as an accumulation of calcium carbonate. Field study in Dona Ana County, New Mexico shows that ca horizons occur in soils on a variety of sediments and geomorphic surfaces. A broad fan piedmont extends from the Rio Grande Valley eastward to the igneous Organ Mountains. To the north there is a desert bolson. In soils on these surfaces and in paleosols underlying the fan piedmont, ca horizons occur and range from thin CaCO3 coatings on pebbles or few CaCO3 filaments to indurated horizons many feet thick. In soils of the study area, ca horizons have been classified as weak, moderate, strong and very strong. The classification is based on field morphology and pertinent laboratory data, including CaCO3 equivalent, particle size distribution, bulk density, unconfined compressive strength and infiltration rate.}, keywords = {article, articles, calcium carbonate ,classification, geomorphology,calcium carbonate horizon, journal, journals, soil, calcium carbonate horizon}, author = {L. H. Gile} } @article {52525, title = {Carotene, vitamin A, and inorganic phosphorus in the blood plasma of range cows}, year = {1958}, note = {//??//NONE//}, month = {1958}, institution = {New Mexico Agricultural Experiment Station}, keywords = {book, books, cattle,biochemistry, cattle,blood plasma, chapter, chapters, report, reports}, isbn = {Bulletin 420}, author = {Repp, W. W. and Watkins, W. E.} } @mastersthesis {52529, title = {Comparative efficiency of various lengths of belt transects in estimating forage production on semidesert grassland range}, year = {1954}, note = {//??//NONE//}, month = {1954}, pages = {32}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, forage production, technique,belt transect, theses, thesis, transect,forage production}, author = {Pino, R.} } @article {52539, title = {The correlation between gains made at different periods by cattle}, journal = {Journal of Animal Science}, volume = {10}, year = {1951}, note = {//??//NONE//(New Mexico Agr. Exp. Station Journal Article 67)//}, month = {1951}, pages = {760-763}, keywords = {article, articles, cattle, production, journal, journals}, author = {Koger, M. and Knox, J. H.} } @article {52543, title = {Carotene and Vitamin A in the blood plasma of range cows}, year = {1950}, note = {//??//NONE//}, month = {1950}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {biochemistry,blood plasma, book, books, carotene,cattle, cattle,biochemistry, cattle,carotene, cattle,Vitamin A, chapter, chapters, report, reports, Vitamin A,cattle}, isbn = {Bulletin 355}, author = {Watkins, W. E. and Knox, J. H. and Benner, J. W.} } @article {52547, title = {Control of noxious range plants in a range management program}, journal = {Journal of Range Management}, volume = {2}, number = {3}, year = {1949}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {July 1, 1949}, pages = {128-132}, abstract = {Plants which are undesirable in light of best land use are called "noxious." On rangelands a noxious plant may be one which competes with the growth of desirable species and reduces grazing capacity, which may be actually poisonous to livestock or which may increase handling costs by its presence. It is the purpose of this paper to point out the place of noxious plant control in a management program.}, keywords = {control, noxious range plants, range management program}, url = {/files/bibliography/072.pdf}, author = {Parker, K. W.} } @article {JRN54391, title = {The carnivores of the San Andres Mountains, New Mexico}, journal = {Journal of Mammalogy}, volume = {27}, year = {1946}, pages = {154-161}, abstract = {

During the period April 14, 1941, to October 26, 1944, opportunities were presented to the writer as refuge manager of the San Andres National Wildlife Refuge to procure data on the Recent carnivores known to occur in the San Andres Mountains of south-central New Mexico. This federal refuge was created in 1941 to protect the Mexican bighorns indigenous to the range (Halloran, 1944). Part of the management work involved a study of the larger carnivores, which included the trapping of predatory mammals on parts of the area. Although Benson (1933) and others have reported in detail regarding the mammals of the adjacent White Sands area, their emphasis was on rodents. The presence of the Jornada Experimental Range, established in 1913 in the southern part of the mountains, has lightened the utilization of the forage by domestic stock, with the result that, in part of the range at least, a high percentage of the original flora and fauna remains. This is in sharp contrast to many other semi-desert ranges of New Mexico where close utilization of the available forage by domestic stock has, in many cases, radically changed the composition of the fauna and flora.

}, keywords = {carnivores, predators, San Andreas Mountains, San Andres Mountains}, author = {A.F. Halloran} } @article {52555, title = {A comparison of gains and carcasses produced by three types of feeder steers}, journal = {Journal of Animal Science}, volume = {5}, year = {1946}, note = {//??//NONE//(New Mexico Agr. Exp. Station Journal Article 40)//}, month = {1946}, pages = {331-337}, keywords = {article, articles, cattle,productivity, journal, journals, productivity,cattle}, author = {Knox, J. H. and Koger, M.} } @article {52570, title = {Control of mesquite on Southwestern ranges}, year = {1943}, month = {October 1943}, pages = {8 }, publisher = {Government Printing Office}, abstract = {Range owners and livestock producers in the Southwest, vitally interested at the present time in greater meat production, have reason to be concerned at the spread of the many-branched, deep-rooted shrubs or trees known as mesquites (Prosopis spp.). These are found in ever-increasing abundance on many grassland ranges of Arizona, New Mexico, Texas, and portions of adjoining states. Much of the original open mesquite woodland in valley bottoms has been converted into thickets (bosques), and many of these have had to be abandoned for grazing on account of the difficulty encountered in gathering and moving cattle. This is especially true wherever screwworms are troublesome. But of even greater concern is the very considerable loss in perennial grass forage that has resulted from the invasion of mesquite into open rangelands. In this respect, mesquite constitutes a menace that in some sections has aroused a determined effort to control the plant or at least to halt further intrusion. On the other hand, mesquite has three undeniable good qualities. Its 4- to 8-inch pods, generally borne in clusters near the branch tips, are relished by livestock, are highly nutritious, and in critical periods when other feed is scarce, have definite value; the leaves are sometimes grazed sparingly, especially in the spring and as emergency forage. Mesquite also supplies fuel wood and post material where other wood is scarce. Lastly, on scantily grassed sandy soils the shrubs and trees perform an important service in holding the soil against wind and water erosion. But here the record of favorable qualities ends, and on most southwestern grassland these are greatly outweighed by the persistent tendency of mesquite to spread and take over an ever-wider hold on the range. This tendency is well illustrated by the contrast between the cover illustration of an all-too-firmly established stand and the view in figure 1 of the same area 38 years earlier.}, keywords = {government publication, invasion, loss of perennial grass forage, meat production, mesquite}, url = {/files/bibliography/064.pdf}, author = {Parker, K. W.} } @article {52571, title = {Composition of range grasses and browse at varying stages of maturity}, year = {1943}, note = {//??//NONE//}, month = {1943}, institution = {New Mexico Agricultural Experiment Station}, keywords = {book, books, cattle grazing,forage composition, chapter, chapters, range grass, rangeland,forage, report, reports}, isbn = {Bulletin 311}, author = {Watkins, W. E.} } @article {52577, title = {Cattle losses reduced by grubbing poisonous drymaria, proven by tests on Jornada Experiment Range}, journal = {New Mexico Stockman}, volume = {6}, number = {10}, year = {1941}, month = {October 1941}, pages = {11-12}, abstract = {Previous to 1926, the cooperating stockmen attributed a large number of livestock deaths each year on the Jornada Experimental Range to lightning. This was thought to be the cause of death in as much as the deaths all occurred during therainy period and the position of the carcasses was such as to lead to the belief that the animals had been killed instantly. Investigation, however, disclosed the fact that practically all these losses, thought to be caused by lightning had been caused by the poisonous weed drymaria, commonly called inkweed because of the purple stain contained in the seed. Drymaria is a small summer annual growing 1 to 3 inches high in round clumps 3 to 6 inches in diameter. It is found mostly in heavy clay soils in adobe flats and along shallow washes or gullies in southwestern Texas, southern New Mexico, and southeastern Arizona. The solitary growth habit of theseplants within areas supporting few, if any other, plants possibly causes them to be grazed to a greater extent than they would if growing with other plants.}, keywords = {drymaria, inkweed, lightning, poisonous weed}, url = {/files/bibliography/055.pdf}, author = {F.N. Ares} } @article {52583, title = {Cutting tobosa grass for hay}, journal = {The Cattleman}, volume = {25}, number = {9}, year = {1939}, month = {1939}, pages = {47-50}, abstract = {Tobosa grass (Hilaria mutica) is one of the important Southwestern range grasses and is found on the plains of western Texas, New Mexico and Arizona. Given a fair amount of winter or early spring moisture, this grass begins its growth very early in the spring and provides a source of green feed highly relished by stock after a winter diet of dry forage. Unlike the highly prized grama grasses of this area, tobosa can withstand the low night temperatures of early spring and, under favorable moisture conditions, will produce a large amount of welcome feed at this critical time of year.}, keywords = {cutting for hay, tobosa grass}, url = {/files/bibliography/043.pdf}, author = {F.N. Ares} } @article {52601, title = {The calcium and phosphorus contents of important New Mexico range forages}, year = {1937}, note = {//??//NONE//}, month = {1937}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, chapter, chapters, nutrients,range forage, range forage,calcium, range forage,phosphorous, report, reports}, isbn = {Bulletin 246}, author = {Watkins, W. E.} } @article {52623, title = {A case of phyllody in Yucca elata}, journal = {Botanical Gazette}, volume = {88}, year = {1929}, month = {1929}, pages = {109-110}, abstract = {Yucca elata Engelm., an evergreen of the family Liliaceae, occurs abundantly over the grasslands of southern New Mexico. In the late spring, after favorable precipitation, the plant produces a long flower stalk surmounted by a great cluster of white- or cream-colored flowers. In observations made on the Jornada Range Reserve, a grazingexperiment station in southern New Mexicoconducted by the United States Forest Service, practically every plant of Yucca elata flowered during May or June of 1926. Later in that summer, several flower stalks were found with leaf clusters instead of flowers. In the summer of 1928, the excellent specimen of phyllody was found on the reserve. All the cases of phyllody have been found from 1-2 months after the regular flowering season for this plant. Observations to date have shown that such unusual flower stalks, as well as the ordinary ones, do not persist in a green condition longer than a year after production.}, keywords = {evergreen, flowering season, phyllody, Yucca elata}, url = {/files/bibliography/015.pdf}, author = {R.S. Campbell} } @article {52622, title = {Conservative grazing, a paying policy}, journal = {The Cattleman}, volume = {16}, number = {4}, year = {1929}, month = {September 1929}, pages = {32-33}, abstract = {

The present status of the range cattle industry in the Southwest is unusual in that the number of stock is relatively low, feed is generally abundant, which produces fat stock, and high prices are being obtained in sales. This combination of favorable circumstances has produced a desire to restock on the part of many ranchmen who feel their ranges might support more cattle than are now grazed. Experimental work on the Jornada Range Reserve in southern New Mexico has shown that the policy toward restocking should always be conservative. The range livestock industry ranks asone of the most important in the Southwest, and to make certain of a sustained, well-paying business, the permanent maintenance of range resources must be assured throughconservative grazing.

}, keywords = {conservative policy, maintenance, range cattle industry, range resources, restocking}, url = {/files/bibliography/018.pdf}, author = {R.S. Campbell and Canfield, R.H.} } @article {52630, title = {The cost of a range calf}, journal = {American Cattle Producer}, volume = {9}, number = {5}, year = {1927}, month = {1927}, pages = {3-6}, abstract = {The problem which first, last and always concerns the cowman, as well as any individual engaged in any line of business, is none other than the time-honored question of making the outfit pay. Owing to adverse conditions that have affectedthe range cattle business during the past 5 years, the cattle grower has not had to worry much about what to do with profits. It has been more a matter of drawing his belt up a little tighter from time to time to meet the demands of lean years. However, conditions have already shown enough improvement so that the cowman can at least begin to look his problems in the face with a full stomach. The cattle business in southern New Mexico has probably suffered more severely than the industry in general. The end of the war foundranges heavilystocked due to patriotic efforts ofcattlemen doing their bit by producing more beef. The drought that prevailed from 1916 to 1918 continued with only short respites through 1922 and 1924. Falling prices, often so low they would not pay freight to central markets, increased the difficulties of reducing herds to a sound basis of stocking the ranges. Through all of this, the cattleman has lived in hopes, but the combined forces of drought, overstocking, deteriorating ranges and depression have been a difficult combination with which to cope.}, keywords = {business, cattle, range}, url = {/files/bibliography/012.pdf}, author = {Schoeller, J.D.} } @article {52639, title = {Calf crop increases on the Jornada}, journal = {Organized Farming}, volume = {3}, number = {3}, year = {1922}, month = {1922}, pages = {1-2}, abstract = {

New Mexico has in the neighborhood of 70,000,000 acres of land chiefly valuable for grazing livestock. About 18,500,000 acres are found in the southern tier of low-rainfall counties. The importance of this vast area in the economic life of New Mexico may be realized when it\’s known that an estimate by the Bureau of Markets and Crop Estimates places the number of cattle in southern New Mexico at 435,000 head, or about 30 per cent of the total in the state. Investigations in range cattle management have been conducted at the Jornada Range Reserve since 1915 by the U.S. Forest Service in cooperation with C.T. Turney, a practical stockman of long experience in the Southwest. Periodic droughts, varying from 1 to 4 years in duration, may occur every 7 to 10 years and play such an important part in range production in the Southwest that any system of range management must take in consideration this factor. The investigators have endeavored to work out an economic system of management for range and stock which would maintain a good breeding herd, regardless of the drought factor and, at the same time, secure highest productivity of the forage and its proper use.

}, keywords = {cattle, forage productivity, management system, New Mexico, range}, url = {/files/bibliography/009.pdf}, author = {Nelson, E. W.} } @article {52640, title = {Chopped soapweed as emergency feed for cattle on Southwestern ranges}, year = {1919}, month = {January 29, 1919}, pages = {20 }, abstract = {Heavy losses of stock resulting from long periods of drought are the greatest handicap of the stock industry on Southwestern ranges. Such droughts have occurred at intervals of 3 to 10 years. When these droughts continue for more than a year, the situation becomes critical due to the lack of range forage or other available feed. Cottonseed products serve well as supplemental feed in times when enough range forage is available to provide the necessary roughage. During prolonged droughts like the present one, which began early in 1916 and continues unbroken to the present (June 15, 1918), the range forage crop may be so small as to require other roughage, as well as concentrated feeds. The problem may be solved in part in some of the less arid regions by raising fodder crops using dry farming. The ranges where this is practical at present, however, are not extensive. On a few ranges adjacent to irrigated districts, the necessary emergency feeds might be furnished by crops from those irrigated areas. But this supply, at best, would be restricted to ranges in the immediate vicinity of the irrigated areas and would not provide emergency feed for the larger portions of the Southwestern ranges where losses have been heavy and breeding herds established through years of effort have been sacrified. In hopes of meeting the problem on such ranges, at least to an extent which will make it possible to maintain the breeding herd over critical periods, the Department of Agriculture has been cooperating for a number of years with a practical stockman on the Jornada Range Reserve in southern New Mexico in working out a comprehensive plan of range management and supplemental feeding. For several years, this plan has included investigating the use of native vegetation as emergency feed. The results of range management with supplemental feeding and initial tests to determine the value of soapweed as ensilage were reported in Department of Agriculture Bulletin 588. Later investigations, including extensive experimental feeding, have shown conclusively that soapweed, if properly utilized, has great value as an emergency stock feed.}, keywords = {cattle, emergency, feed, government publication, soapweed, Southwestern ranges}, url = {/files/bibliography/007.pdf}, author = {Forsling, C.L.} } @article {52642, title = {Certain desert plants as emergency stock feed}, year = {1918}, month = {December 18, 191}, pages = {31 }, publisher = {Government Printing Office}, abstract = {It has been the practice for a long time in certain parts of the arid Southwest, mostly in what is known as the Big Bend region of southern Texas, to feed sotol to range stock during seasons when the usual range feed is scarce. This custom is probably one that originated in Mexico where this plant is used more or less extensively for human food, as well as for the production of an alcoholic beverage where, consequently, its qualities are well known. Hitherto, the usual method of preparing sotol for stock feed has been to cut the stem off at the ground and, with a machete or an axe, split open the head, which is formed of the enlarged leaf bases and the thickened top of the stem. This process exposes the soft tissue of the head to the animals, and either cattle or sheep may be expected to "do the rest." The past two seasons, 1916 and 1917, have been unusually dry in the whole of the arid Southwest from central Texas to the Pacific coast; and, in consequence, the normal crop of range feed did not grow. In many cases, farsighted stockmen sold off some of their animals or moved them to other places to adjust the number kept on their ranges to the amount of feed available. If present on their lands, many have successfully fed prickly pear to their animals. Notwithstanding the recognized necessity for a reduction in the numbers of animals upon the range, there were many men who, for one reason or another, were unable to sell or move their animals. Under such circumstances, the only possible alternatives were to feed the animals or let them die. The idea of feeding range stock is not new to most of the stockmen in western Texas and southern California. But for the men in southern New Mexico and southern Arizona, who are almost without exception cattlemen, the practice is largely a new one, though some have heard of using sotol as forage and some who have lived in Texas have practiced using sotol as feed. Sotol occurs only in a very small part of the country where feed was scarce this past year, but in much of this area, there{\textquoteright}s a greater or lesser amount of other usable plant species. Stimulated by the patriotic desire to avoid all possible losses of meat animals, as well as probable serious financial loss, the more enterprising men began casting about for feed of one kind or another. Many of the men in Texas had already laid in a supply of cottonseed cake or meal. Some were able to buy milo maize, kafir corn or hay of some kind. But the supply of many of these feeds was below normal for the region because of the drought, all were abnormally expensive and transportation systems were greatly overworked, hence, the need to use all kinds of feed available on the ranges. It is difficult to determine just who should be credited with the idea of using certain plants, other than sotol, that grow abundantly in some places in the region. The practice seemsto have arisen independently in several places at about the same time, both in Arizona and in New Mexico. The first to suggest using any of these plants for feed, of which the present writer is aware, was made to him in 1914 by Mr. C.T. Turney of Mesilla Park, NM. Mr. Turney{\textquoteright}s idea was to use the tops of a species of yucca (Yucca elata), locally known as soap weed, for silage. Mr. Turney was cooperating with the United States Department of Agriculture on the Jornada Range Reserve near Las Cruces, NM, in handling more than 5,000 cattle under the range conditions of that region. It was here, in 1915, that the first controlled experiments in feeding chopped soap weed to range cattle were begun. Cutting up the tops with an ordinary silage cutter was found to be difficult, and the chopped material was not altogether satisfactory because the machine used was too light for the work. Mr. Turney asked a firm of manufacturers at El Paso, TX, for a heavier machine, which they proceeded to design and make. This machine has been in use for some time in southern New Mexico and is the first of a number since made and now in use. It{\textquoteright}s heavy enough to cut up the stalks of the soap weed, and thus the discovery was made that the stalks are better feed than the tops.}, keywords = {emergency, forage, government publication, soapweed, sotol, stock feed}, url = {/files/bibliography/006.pdf}, author = {Wooton, E.O.} } @article {52650, title = {Cacti in New Mexico}, year = {1911}, note = {//??//NONE//updated 8/21/2006}, month = {1911}, institution = {New Mexico Agricultural Experiment Station}, address = {Las Cruces, New Mexico}, keywords = {book, books, cactus, chapter, chapters, report, reports}, isbn = {Bulletin 78}, url = {/files/bibliography/027.pdf}, author = {Wooton, E.O.} }