@proceedings {JRN55396, title = {Field testing of LoRa-WAN sensors for real-time tracking and biosensing of Brangus and Raramuri Criollo cattle foraging on a small pasture}, year = {2022}, month = {3/21/2022}, abstract = {The study{\textquoteright}s objective was to investigate the use of Internet of Things (IoT) biosensors using Long Range Wide Area Network (LoRa-WAN) communication to compare the foraging behavior of two desert adapted cattle breeds. Two groups of mature Brangus (BA) and Raramuri Criollo (RC) cows were introduced into a small pasture (38ha) of native grassland and irrigated winter wheat at the New Mexico State University Clayton Livestock Research Center during Dec-Jan, 2021 (41-days). The real-time position and activity count data (15- and 1-minute interval, respectively) were retrieved continuously from 4 BA and 5 RC cows collared with commercially available trackers. Response variables derived from GPS records included daily distance traveled (Dist) and daily area explored (Area). Response variables derived from accelerometers included daily percentage motion (\%Act) and cumulative activity data (CumAct). All variables were grouped into six consecutive weekly periods and analyzed by a repeated measures mixed model that included the fixed effects of BREED, WEEK, and the BREED*WEEK interaction in a completely randomized design. A significant BREED*WEEK interaction was detected on all GPS-derived variables, with RC exhibiting a trend to explore larger areas than BA (P=0.06). For the accelerometer-derived variables, the BREED*WEEK interaction was only significant for CumAct. Overall, BA spent a larger percentage of the day active (\%Act), while investing a significantly~ greater overall activity (CumAct) compared to RC cows. The lack of sensitivity of GPS-derived variables is hypothesized to be the result of aggregating errors associated with less frequent GPS location measurements coupled with position errors (~5m) and a low success rate of data packet transmission (~40\%). In contrast, the more frequent inherent data packaging of successive accelerometer data represented as cumulative guaranteed low data loss rates. The spatial scale of the study is hypothesized to have influenced the differences in foraging behavior observed between breeds and the better performance of the accelerometer vs. GPS-derived variables. }, author = {S. Nyamuryekung{\textquoteright}e and G. Duff and Andr{\'e}s F. Cibils and Richard E. Estell and S. A. Utsumi and M. Funk and Andrew Cox and Qixu Gong and S. Spiegal and V. Gouvea and Carolina Brandani} } @proceedings {JRN55364, title = {From desert pasture to dinner plate: Evaluating the sustainability of supply chains for beef cattle coming from ranches of the Southwest}, year = {2022}, month = {2/10/2022}, abstract = {Consumers and producers worldwide are paying attention to the environmental and social outcomes of beef production. The Society for Range Management knows that rangeland cattle production can impart a light environmental footprint, and sometimes even improve ecosystem services from rangelands, while being central to rural livelihoods. However, the environmental and social outcomes of beef that originates on grazinglands is integrally tied with processing, distribution, and consumption beyond ranch gates. In this symposium we will explore the connections among the links of the supply chains originating on ranches of the southwestern US and evaluate strategies for sustainability from pasture to plate, even in the face of a warming and drying climate. To encourage audience participation, we will provide a whiteboard or sticky note activity after each presentation to solicit feedback from the audience about applicability of the topic to their work, as well as suggestions for improving applicability more broadly.}, keywords = {beef cattle, desert, dinner plate, evaluating, pasture, ranches, Southwest, supply chains, sustainability}, author = {S. Spiegal and Jean Steiner and Skye Aney and Matthew M. McIntosh} } @proceedings {JRN55357, title = {Facilitating knowledge exchange around strategies for sustainability}, year = {2021}, month = {12/9/2021}, abstract = {Economic and environmental stresses on cattle producers in the Southwest, already operating on very narrow margins, are predicted to intensify under a warmer, drier, future (Spiegal et al. 2020). Reduction in carrying capacity of some rangeland sites has already been documented (McIntosh et al. 2019), spurring the need to find new ways to adapt to old but intensifying problems of aridity and frequent drought in the region. Over the course of the past year, the Sustainable Southwest Beef Project{\textquoteright}s extension team has undertaken a number of activities to facilitate knowledge exchange around strategies which may enhance cattle production in the southwest under future conditions. Here we present highlights from these efforts. All products described here can be accessed at https://southwestbeef.org/.}, keywords = {cattle producers, Economic, environmental stresses, sustainability}, url = {files/bibliography/21-060.pdf}, author = {Skye Aney and Emile H. Elias and Reanna Burnett and Craig Gifford and G. Duff and BW Auvermann and Jean Steiner} } @conference {JRN55304, title = {Feeding habits of Brangus and Raramuri Criollo cows grazing Chihuahuan Desert rangeland}, booktitle = {Society for Range Management Meeting Abstracts}, year = {2021}, month = {02/15/2021}, abstract = {Heritage cattle breeds may help improve sustainability of ranching in the arid Southwest. Foraging behavior of Raramuri Criollo (RC, heritage breed) and Brangus (BR) cows was observed to determine whether breeds differ in the amount of browse included in their diets. Cattle were monitored by a single observer who scan sampled groups of 3 to 16 animals at 30 second intervals for 30 minutes during morning and afternoon foraging bouts to determine frequency of grazing vs. browsing. To the best of the observer{\textquoteright}s ability cattle were undisturbed while monitoring. Observations were conducted on 29 or 23 days in spring and summer, respectively. A total of 5,824 (3,521 RC, 2,303 BR) and 7,120 (3,429 RC, 3,691 BR) in spring and summer, respectively, were summarized and analyzed. Analysis of Variance using PROC GLM in SAS 9.4 to determine the effect of breed and season on frequency of browsing and grazing of cattle in this study. LS means were compared using the Tukey-Kramer test. We found a significant breed-by-season interaction for browsing (P< 0.01) and grazing (P< 0.01) frequency, therefore breed differences in feeding habits depended on the season considered. In spring, RC cows were observed browsing more often (64.4 \%; P = 0.08) and grazing less often (35.6\%; P = 0.08) than BR cows (browsing: 29.7\%; grazing: 70.3\%). In summer, no differences between breeds were observed (P > 0.10). RC were observed browsing more often (P=0.02) and grazing less often (P= 0.02) in spring than in summer whereas BR showed no statistically detectable seasonal differences in grazing and browsing frequency (P > 0.1). Our results, while preliminary, suggest that relative to BR, heritage cows grazing Chihuahuan Desert rangeland include more browse in their diets during spring and exhibit higher seasonal plasticity of feeding habits.}, author = {Danielle Duni and Andr{\'e}s F. Cibils and Richard E. Estell and Andrew Cox and Matthew M. McIntosh and S. Spiegal} } @article {JRN55328, title = {Foraging behavior and body temperature of heritage vs. commercial beef cows in relation to desert ambient heat}, journal = {Journal of Arid Environments}, volume = {193}, year = {2021}, month = {6/20/2021}, pages = {104565}, abstract = {We studied foraging patterns of Raramuri Criollo (heritage breed, {\textquotedblleft}RC{\textquotedblright}) and Angus x Hereford (commercial beef breed, {\textquotedblleft}AH{\textquotedblright}) cows in relation to ambient heat and body temperature during summer (2016 and 2017) and winter (2017 and 2018) in the Chihuahuan Desert. Cows of each breed grazed separately in two adjacent pastures (~1100 ha) in a crossover design for four weeks in each season/year. Animals were fitted with temperature loggers attached to blank CIDRs (Controlled Internal Drug Release device) devoid of hormones that recorded body temperature (BodyT), and GPS collars that recorded position and ambient temperature (CollarT). All sensor data were logged at 10 min intervals. A landscape thermal map (LandT) was developed from Landsat satellite imagery for habitat analysis using GPS locations chosen by individual collared cows, and air temperature (AirT) was recorded by a nearby weather station. Data were analyzed within four daytime segments: dawn (sunrise {\textendash} 9AM); pre-noon (9AM {\textendash} noon); post-noon (noon {\textendash} 3PM); and dusk (3PM {\textendash} sunset). ANOVA was used to determine whether BodyT, CollarT, LandT selection, or animal movement variables within each of the four daily segments differed (P < 0.05) for RC vs. AH cows. BodyT and CollarT increased as day progressed in both seasons. During summer, RC had lower BodyT and higher CollarT than AH (P < 0.05) during the hottest hours of the day. Increasing AirT throughout the day was associated with selection of cooler LandT in RC but not AH during summer. In winter, both breeds selected warmer landscape locations as the day progressed. Compared to AH, RC cows traveled farther, at higher velocities, and spent more time grazing and traveling and less time resting, with largest breed differences observed during the hottest hours of summer days. These results suggest that Raramuri Criollo cows exhibited higher thermotolerance than did AH. Elevated ambient summer temperatures in the Chihuahuan Desert appear to impose fewer constraints on heritage RC movement patterns compared to mainstream commercial AH cows.}, keywords = {Chihuahuan Desert, climate change, Raramuri Criollo, thermotolerance}, doi = {10.1016/j.jaridenv.2021.104565}, url = {files/bibliography/21-038.pdf}, author = {S. Nyamuryekung{\textquoteright}e and Andr{\'e}s F. Cibils and Richard E. Estell and Matthew M. McIntosh and D. VanLeeuwen and Caitriana Steele and Amy L. Gonzalez and S. Spiegal and Leonel Avenda{\~n}o Reyes and Felipe A. Rodr{\'\i}g Almeida and Martha Anderson} } @article {JRN55271, title = {Foraging Behavior of Heritage versus Desert-Adapted Commercial Rangeland Beef Cows in Relation to Dam-Offspring Contact Patterns}, journal = {Rangeland Ecology \& Management}, volume = {74}, year = {2021}, month = {11-02-2021}, pages = {43-49}, abstract = {We compared cow-calf contacts, as well as movement, activity, and pasture use patterns of heritage Raramuri Criollo (RC) and desert-adapted commercial Angus Hereford crossbred (AH) beef cattle grazing Chihuahuan Desert pastures during 4 wk in the summers of 2016 and 2017. Within each herd of 11 cow-calf pairs, a group of 7 -9 randomly elected cows were fitted with Global Positioning System collars that recorded animal position at 10-min intervals. Proximity loggers configured to record contact events ( < 1-m radius) were fitted on a subset of five cow-calf pairs of each breed. The effect of breed on cow-calf contacts, as well as the dams{\textquoteright} movement, activity, and pasture use patterns were analyzed via mixed analysis of variance models. A higher number of RC cow-calf contacts occurred while the dam was grazing and traveling compared with AH counterparts ( P <=0.05). No breed-related differences were observed in the overall number and duration of cow-calf contact events. Compared with AH dams, RC cows traveled farther each day (RC: 7.51 vs. AH: 4.85 km, P < 0.01) at higher movement velocities (5.46 vs. 3.53 m. min -1 , P < 0.01) and spent more time traveling (1.05 vs. 0.48 h, P < 0.01), more time grazing (9.37 vs. 7.45 h, P < 0.01), and less time resting (13.07 vs. 15.68 h, P < 0.01). RC cows explored almost three times more daily area than AH (152.30 vs. 57.69 ha, P = 0.01) but spent similar amounts of time within 200 m and 100 m of a drinker. RC calves explored larger daily areas than their AH counterparts (83.0 vs. 20.8 ha, P = 0.05), but no breed differences were detected in the number of contact events near drinkers. RC calves possibly impose fewer constraints on their dams{\textquoteright} movement and activity patterns compared with commonly used British crossbreds when grazing the Chihuahuan Desert during summer.}, keywords = {Angus, grazing behavior, Heritage genetics, range cattle, Raramuri Criollo}, doi = {10.1016/j.rama.2020.11.001}, url = {files/bibliography/21-002.pdf}, author = {S. Nyamuryekung{\textquoteright}e and Andr{\'e}s F. Cibils and Richard E. Estell and Matthew M. McIntosh and D. VanLeeuwen and Caitriana Steele and Amy L. Gonzalez and S. Spiegal and F. G. Continanza} } @article {JRN55415, title = {A framework for sustainable management of ecosystem services and disservices in perennial grassland agroecosystems}, journal = {Ecosphere}, volume = {12}, year = {2021}, month = {11/24/2021}, pages = {e03837}, abstract = {Increasing demand for agricultural products is driving grassland management intensification with subsequent impacts on ecosystem services and disservices. Key questions related to grassland production as well as environmental and social concerns must be addressed to ensure sustainability. We propose a unified perspective, addressing numerous trade-offs and synergies between grassland ecosystem services and disservices, and considering an array of ecological and human consequences associated with history and ongoing shifts in management strategies. Much of our discussion utilizes evidence from humid grasslands; however, our examples and recommendations have global implications for the future of grassland management. We characterize four categories of ecosystem services and disservices (provisioning, supporting, regulating, and cultural) provided by perennial grasslands that are extensively managed (low or no input, never cultivated) or intensively managed (high-input, cultivated). We explore a range of potential outcomes following transition from extensive to intensive agroecosystems around the globe. Additionally, we suggest specific research priorities to better evaluate ecosystem services and disservices across management intensities. Finally, we highlight potential benefits of landscape mosaics that include grasslands across a continuum of extensive to intensive strategies.}, keywords = {biodiversity; conservation and production; extensively managed; greenhouse gases; intensively managed; pasture; rangeland; semi-natural; trade-offs}, doi = {10.1002/ecs2.3837}, url = {files/bibliography/21-065.pdf}, author = {Shishir Paudel and Adam B. Cobb and Elizabeth H. Boughton and S. Spiegal and Maria L. Silveira and Hilary M. Swain and Ryan Reuter and Laura E. Goodman and Jean Steiner} } @conference {JRN55203, title = {fDNA-based diet selection by Raramuri Criollo and Angus crossbreeds in the Chihuahuan Desert}, booktitle = {Society for Range Management}, year = {2020}, month = {02/2020}, address = {Denver, CO}, abstract = {A 3-year diet study was conducted in two pastures on the Jornada Experimental Range in the northern Chihuahuan Desert, Dona Ana County, New Mexico, USA to compare diets of Raramuri Criollo and Angus x Hereford crossbreed cattle. Fecal samples were collected directly from cattle and analyzed with both Operational Taxonimic Units (OTUs) and Exact Sequence Variants (ESVs). ESVs performed better than OTUs at discriminating between plant taxa. Although patterns of plant preference between the two breeds were not necessarily constant over time, Criollo diets were were found to have proportionally more Honey mesquite (Prosopis glandulosa) and proportionally less Black grama (Bouteloua eripoda) than Angus x Hereford crossbreeds. In general, both breeds consumed proportionally more grass in the winter than in the summer. However, the grass component for both breeds decreased over time, likely due to persistent drought which caused less grass production and availability. Both breeds behaved the same way by replacing the grass component with forbs in the summer and with shrubs in the winter. This study is an example of how fecal DNA analyses can illustrate how livestock alter their diets to cope with drought.}, author = {D. K. James and Richard E. Estell and Andr{\'e}s F. Cibils and S. Spiegal and S. Nyamuryekung{\textquoteright}e and Matthew M. McIntosh and Amy L. Gonzalez and Kirsten B. Romig} } @conference {JRN55251, title = {Feast or famine: Climate impacts on agriculture using crop insurance data}, booktitle = {American Geophysical Union}, year = {2019}, month = {12/2019}, address = {San Francisco, California}, abstract = {The federal crop insurance program has paid out over $120 billion between 1989 and 2017 due to weather and climate-driven events. Operated by the U.S. Department of Agriculture Risk Management Agency, the taxpayer-subsidized program is an important financial safety net to our farmers, ranchers, and landowners. However, climate change is expected to increase programmatic costs, decrease agricultural production, and threaten rural communities{\textquoteright} economic livelihoods and wellbeing. Our objectives are to: (1) present methods to analyze and visualize long-term crop insurance losses, (2) report on significant patterns and trends of crop loss, and (3) share an online tool used to engage stakeholders using these data to enhance their risk management decision making. We performed a retrospective analysis of crop insurance loss data from 1989 to 2017 at multiple spatial and temporal scales. We found that drought and excess moisture were the leading two causes of crop loss across the Nation resulting in $79.6 billion in indemnities, or insurance payouts, and comprising 61\% of total indemnities. Monthly and regional patterns of crop loss demonstrated the capability of crop insurance loss data to act as an integrator of environmental, socio-economic, and management factors. Trend analyses revealed divergent patterns of risk and a {\textquoteleft}feast or famine{\textquoteright} storyline of water with either too much, or too little, causing significant crop loss. These also suggested areas of higher production risk related to different weather and climate-driven events. Some areas may perceive hail as a greater risk, and therefore increase insurance coverage to hedge and minimize risk. In other areas, adaptive capacity of producers may be limiting losses. Finally, we developed the AgRisk Viewer, a web-based platform to make these data accessible, discoverable, and usable to our agricultural stakeholders. This information helps to identify high production risk areas, and thus enables climate-informed agricultural risk management ensuring viable and sustainable landscapes. Poster $\#$528860.}, author = {J.T. Reyes and Emile H. Elias} } @proceedings {JRN55176, title = {Factors determining spread of Vesicular Stomatitis across heterogeneous landscapes: an application of landscape connectivity and AI in disease ecology}, year = {2019}, month = {August 11-16, 20}, address = {Louisville, Kentucky}, abstract = {

Background/Question/Methods

Vesicular Stomatitis (VS) is a vector-borne livestock disease that emerges in the United States (US) approximately every 10 years. After emerging, this disease spreads across the western US in a generally northward direction from spring to winter with the possibility of over-wintering and then continuing to spread the following year. To characterize the spatiotemporal dynamics of this disease in relation to the landscape heterogeneity over which it spreads, we used a landscape connectivity approach in five regions of the western US. The landscapes are represented by a diverse set of geospatial data, including flowing and standing surface water, soil properties, land use and land cover, and topography. VS incidence records from 2004-2006 and 2014-2015 were used in conjunction with landscape properties data to build a resistance surface, i.e. a geospatial data layer representing the lack of suitability for the disease, and then to predict the connected corridors of VS spread where the cumulative cost to travel between incidences is minimized. We also devised an adaptive artificial intelligence (AI) system to integrate the knowledge gained from the multiple regions and incidence years to improve predictions of future emergence patterns. \  Results/Conclusions The models indicate that suitability of VS spread is primarily driven by proximity to surface water, but that the relative importance of landscape properties varies between (i) the time of year, and (ii) the landscape region. The connected corridors estimated from these resistance surfaces indicate the likelihood of VS between known incidences. Cross-validation from withheld testing sets supports the estimated corridors. The AI system successfully integrated the collection of predicted corridors into an evolving system of VS spread. By predicting the likely routes of disease spread, mitigation strategies in future emergence cases can be designed to mitigate spread in these corridors.

}, author = {Heather Savoy and Debra C. Peters and Emile H. Elias and Angela Pelzel-McCluskey and Luis L Rodriguez and J. D. Derner and David McVey} } @proceedings {JRN55168, title = {The fourth national climate assessment, Chapter 25: Southwest}, year = {2018}, month = {12/10/2018}, abstract = {

Assessing regional-scale vulnerability of agricultural systems to climate change and variability is vital in securing food and fiber systems, as well as sustaining rural livelihoods. Farmers, ranchers, and forest landowners rely on science-based, decision-relevant, and localized information to maintain production, ecological viability, and economic returns. This paper synthesizes the collection of research on the future of agricultural production in the Southwestern United States. The American Southwest is a region of highly variable precipitation. Researchers expect warmer and drier conditions resulting in extended droughts.\  A variety of assessment methods indicate the diverse impacts and risks across the Southwest, often related to water availability, which drives adaptive measures in this region. Sector- or species-specific adaptive measures have long been practiced in this region, and will continue to support agricultural production as a regional enterprise. Diversification of crop selection and income source imparts climate resilience for both producers and consumers. Using alternate livestock breeds may offer another adaptive measure to cope with warming temperatures. Amid hotter and drier conditions shared goals of natural resources stewardship and sustainable production have yielded collaborative partnerships poised to adaptively manage resources, such as the Malpai Borderland Group. The persistence and adaptive capacity of agriculture in the water-limited Southwest serves as an instructive example for producers outside the region expecting drier and warmer conditions, and may offer solutions to reduce future climate risk.

}, author = {Gonzalez, P. and Garfin, G. and David D. Breshears and Broks, K. and Emile H. Elias and Huntly, N. and Maldonado, J. and Mantua, N. and Margolis, H. and Udall, B.} } @article {JRN54821, title = {Fine-Resolution Repeat Topographic Surveying of Dryland Landscapes Using UAS-Based Structure-from-Motion Photogrammetry: Assessing Accuracy and Precision against Traditional Ground-Based Erosion Measurements}, journal = {Remote Sensing }, volume = {9}, year = {2017}, month = {2017}, pages = {1-24}, type = {Journal Article}, chapter = {437}, abstract = {

Structure-from-motion (SfM) photogrammetry from unmanned aerial system (UAS) imagery is an emerging tool for repeat topographic surveying of dryland erosion. These methods are particularly appealing due to the ability to cover large landscapes compared to field methods and at reduced costs and finer spatial resolution compared to airborne laser scanning. Accuracy and precision of high-resolution digital terrain models (DTMs) derived from UAS imagery have been explored in many studies, typically by comparing image coordinates to surveyed check points or LiDAR datasets. In addition to traditional check points, this study compared 5 cm resolution DTMs derived from fixed-wing UAS imagery with a traditional ground-based method of measuring soil surface change called erosion bridges. We assessed accuracy by comparing the elevation values between DTMs and erosion bridges along thirty topographic transects each 6.1 m long. Comparisons occurred at two points in time (June 2014, February 2015) which enabled us to assess vertical accuracy with 3314 data points and vertical precision (i.e., repeatability) with 1657 data points. We found strong vertical agreement (accuracy) between the methods (RMSE 2.9 and 3.2 cm in June 2014 and February 2015, respectively) and high vertical precision for the DTMs (RMSE 2.8 cm). Our results from comparing SfM-generated DTMs to check points, and strong agreement with erosion bridge measurements suggests repeat UAS imagery and SfM processing could replace erosion bridges for a more synoptic landscape assessment of shifting soil surfaces for some studies. However, while collecting the UAS imagery and generating the SfM DTMs for this study was faster than collecting erosion bridge measurements, technical challenges related to the need for ground control networks and image processing requirements must be addressed before this technique could be applied effectively to large landscapes.

}, keywords = {dryland erosion, erosion bridge, photogrammetry, road network disturbance, UAS}, doi = {10.3390/rs9050437}, author = {Jeffrey K. Gillan}, editor = {Jason W. Karl} } @article {JRN54844, title = {Fine-Resolution Repeat Topographic Surveying of Dryland Landscapes Using UAS-Based Structure-from-Motion Photogrammetry: Assessing Accuracy and Precision against Traditional Ground-Based Erosion Measurements}, journal = {Remote Sensing}, volume = {9:437}, year = {2017}, month = {05/2017}, abstract = {

Structure-from-motion (SfM) photogrammetry from unmanned aircraft system (UAS) imagery is an emerging tool for repeat topographic surveying of dryland erosion. These methods are particularly appealing due to the ability to cover large landscapes compared to field methods and at reduced costs and higher spatial resolution compared to airborne laser scanning. However, a systematic comparison between aerial SfM and ground-based methods at multiple points in time has not been investigated. Here we compare the measurement of topographic profiles between erosion bridges and very-high resolution digital elevation models (DEMs) reconstructed with SfM methods from a fixed-wing UAS. In addition to accuracy, we investigated the repeatability of the DEMs which determined the level of detectable change in a survey time-series. Finally, we tested the effect of ground control point (GCP) spacing and quantity on accuracy and precision of the DEMs. We found strong vertical agreement (accuracy) between the methods and virtually no differences using 12 GCPs (RMSE 2.9 cm) and 3 GCPs (RMSE 3.0 cm) to reconstruct DEMs. Vertical repeatability was found to have RMSE 2.7 cm using 12 GCPs and RMSE 2.8 cm using 3 GCPs. The results from repeat UAS imagery, SfM processing, and strong agreement and precision compared with ground-based measures here suggests these technologies can help increase our understanding of soil loss patterns over large landscapes. Applications of this method could include unpaved road network monitoring, compliance monitoring for oil and gas exploration and development, pipeline installation, and other land management challenges.

}, doi = {10.3390/rs9050437}, url = {files/bibliography/17-028.pdf}, author = {Jeffrey K. Gillan and Jason W. Karl and Ahmed Elaksher and Danielle Duni} } @article {JRN54918, title = {Factors associated with nest survival of Black-throated Sparrows, desert-breeding nest-site generalists.}, journal = {Journal Of Field Ornithology}, volume = {88(3):274-287}, year = {2017}, month = {09/2017}, abstract = {

Black-throated Sparrows (Amphispiza bilineata) are common breeding birds throughout thedesert regions of North America and can be considered nest-site generalists. Information about how spatial(e.g., vegetation) and temporal factors in{\textquoteright}uence nest survival of these sparrows is lacking throughout their range. Our objective was to examine the spatial and temporal factors associated with nest survival of Black-throated Sparrows at the nest and nest-patch scales in the predator-rich environment of the northern Chihuahuan Desert of New Mexico. We used a logistic-exposure model {\textquoteright}t within a Bayesian framework to model the daily survival probability of Black-throated Sparrow nests. Predation was the leading cause of nest failure, accounting for 86\% of failed nests. We found evidence of negative associations between nest survival and both vegetative cover above nests and shrub density within 5 m of nests. We found no support for other habitat covariates, but did {\textquoteright}nd strong evidence that daily survival rate was higher earlier in the breeding season and during the egg-laying stage. A decline in nest survival later in the breeding period may be due to increased predator activity due to warmer ambient temperatures, whereas lower survival during the incubation and nestling stages could be a result of increased activity at nests. A generalist approach to nest-site selection may be an adaptive response to the presence of a diverse assemblage of nest predators that results in the reduced in{\textquoteright}uence of spatial factors on nest survival for Black-throated Sparrows.

}, doi = {10.1111/jofo.12209}, url = {files/bibliography/17-034.pdf}, author = {Kozma, Jeffrey and Laura M. Burkett and Kroll, Andrew and Thornton, Jamie and Matthews, Nancy} } @article {JRN54576, title = {Few multiyear precipitation{\textendash}reduction experiments find a shift in the productivity{\textendash}precipitation relationship}, journal = {Global Change Biology}, volume = {22}, year = {2016}, pages = {2570-2581}, abstract = {

Well-defined productivity{\textendash}precipitation relationships of ecosystems are needed as benchmarks for the validation of land models used for future projections. The productivity{\textendash}precipitation relationship may be studied in two ways: the spatial approach relates differences in productivity to those in precipitation among sites along a precipitation gradient (the spatial fit, with a steeper slope); the temporal approach relates interannual productivity changes to variation in precipitation within sites (the temporal fits, with flatter slopes). Precipitation{\textendash}reduction experiments in natural ecosystems represent a complement to the fits, because they can reduce precipitation below the natural range and are thus well suited to study potential effects of climate drying. Here, we analyse the effects of dry treatments in eleven multiyear precipitation{\textendash}manipulation experiments, focusing on changes in the temporal fit. We expected that structural changes in the dry treatments would occur in some experiments, thereby reducing the intercept of the temporal fit and displacing the productivity{\textendash}precipitation relationship downward the spatial fit. The majority of experiments (72\%) showed that dry treatments did not alter the temporal fit. This implies that current temporal fits are to be preferred over the spatial fit to benchmark land-model projections of productivity under future climate within the precipitation ranges covered by the experiments. Moreover, in two experiments, the intercept of the temporal fit unexpectedly increased due to mechanisms that reduced either water loss or nutrient loss. The expected decrease of the intercept was observed in only one experiment, and only when distinguishing between the late and the early phases of the experiment. This implies that we currently do not know at which precipitation{\textendash}reduction level or at which experimental duration structural changes will start to alter ecosystem productivity. Our study highlights the need for experiments with multiple, including more extreme, dry treatments, to identify the precipitation boundaries within which the current temporal fits remain valid.

}, keywords = {aboveground productivity, ANPP, drought, precipitaiton, precipitation-reduction experiments, spatial fit, temporal fit}, doi = {10.1111/gcb.13269}, url = {files/bibliography/JRN54576.pdf}, author = {Marc Estiarte and Sara Vicca and Josep Pe{\~n}uelas and Michael Bahn and Claus Beier and Bridget A. Emmett and Philip A. Fay and Paul J . Hanson and Roland Hasibeder and Jaime Kigel and G. Kroel-Dulay and Klaus Steenberg Larsen and Lellei -Kov{\'a}cs, Eszter and Jean-Marc Limousin and Ogaya, Rom{\`a} and Jean-Marc Ourcival and Sabine Reinsch and O. E. Sala and Inger Kappel Schmidt and Marcelo Sternberg and Tielb{\"o}rger, Katja and Albert Tietema and Ivan A. Janssens} } @conference {JRN54644, title = {From wildlife biology to soil science, the USDA and the United Nations}, booktitle = {2016 Ecological Society of America Meeting}, year = {2016}, month = {08/2016}, publisher = {Ecological Society of America Meeting}, organization = {Ecological Society of America Meeting}, address = {Fort Lauderdale, FL}, abstract = {

It all(?) started at age 18, wearing a rented tuxedo at the Explorers Club in NYC. I tried to explain my high school research on pine marten to my dinner companions while perched nervously on the dais. I haven{\textquoteright}t worn a penguin suit since, but every year has been just as fascinating as I{\textquoteright}ve worked my way down the {\textquotedblleft}food chain{\textquotedblright} from predators to prey to plants to soils, and up from science to management to policy, all thanks to an incredible series of careers, and amazingly just one job, as a research scientist with the USDA Agricultural Research Service.

}, author = {Jeffrey E. Herrick} } @conference {JRN54625, title = {From linear to generalized linear mixed models: A case study in repeated measures}, booktitle = {2016 American Statistical Association (ASA) Conference on Statistical Practice}, year = {2016}, month = {02/2016}, publisher = {2016 American Statistical Association (ASA)}, organization = {2016 American Statistical Association (ASA)}, address = {San Diego, CA}, abstract = {

Compared to traditional linear mixed models, generalized linear mixed models (GLMMs) can offer better correspondence between response variables and explanatory models, yielding more efficient estimates and tests in the analysis of data from designed experiments. Using proportion data from a designed experiment with repeated measures, results from several candidate GLMMs implemented with different distributions (binomial and beta), likelihood estimation methods (integral approximation and PL), covariance structures, and bias correction methods, are compared. The results show that constructing an appropriate GLMM is not trivial, especially in the case of repeated measures. \ The numerical estimation procedures GLMMs utilize can easily produce intractable or nonsensical results that are difficult to diagnose and rectify. \ Many common adjustments and modeling decisions fundamentally change the model{\textquoteright}s inference space and alter appropriate interpretations of model parameters. \ Modelers must also confront mean-variance dependency, important differences between conditional ({\textquotedblleft}G-side{\textquotedblright}) and marginal ({\textquotedblleft}R-side{\textquotedblright}) formulations of random effects, and how to implement bias correction. \ 

}, author = {D. K. James} } @conference {JRN54516, title = {Fire in desert grassland region of the southwestern USA: where and why}, 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 = {

Fire is an important driver of ecological processes in semiarid systems and serves a vital role in shrub-grass interactions. In desert grasslands of the Southwestern US, the loss of fire has been implicated as a primary cause of shrub encroachment. Where fires can currently be re-introduced and managed given past state changes and recent restoration actions, however, is unknown and controversial. Biophysical variables that influence fuel load and quality are commonly employed to model fire distributions; however, soil-landscape properties like those captured by ecological site descriptions are rarely employed to model fire probability. We characterized the spatial distribution of fire in the Chihuahuan Desert and Madrean Archipelago ecoregions and investigated the influence of soil properties and ecological site groups compared to other commonly used biophysical variables using multi-model inference techniques.\  Soil-landscape properties significantly influenced the spatial distribution of fire ignitions. Bottomland ecological sites (i.e., soil-landscape classes) experienced more fires than expected in contrast to ecological sites with coarse soil textures and high fragment content that experienced fewer fire ignitions than expected. Influences of mean annual precipitation, distance to road/rail, soil available water holding capacity (AWHC) and topographic variables varied between ecoregions and by political jurisdictions and differed for peak and nonpeak fire seasons. AWHC explained more variability of fire ignitions in the Madrean Archipelago compared to the Chihuahuan Desert.\  Understanding the spatiotemporal distribution of recent fires in desert grasslands is needed to\  manage fire and predict responses to climate change. While climate variables have proven useful for predicting fire patterns in most systems, the use of landscape units such as ecological sites presents an opportunity to improve predictions at management scales. The application of soil property information readily available in soil survey is an important addition to the toolbox for predicting and managing fire.

}, author = {Matthew Levi and Brandon T Bestelmeyer} } @proceedings {JRN54573, title = {From landscape to domain: Soils role in landscape classifications}, year = {2016}, month = {3/2016}, publisher = {International Soil Modeling Consortium (ISMC) Inaugural Workshop}, address = {Austin, TX}, abstract = {Soil landscape classifications are designed to divide landscapes into units with significance for the provisioning and regulating of ecosystem services and the development of conservation plans for natural resources. More specifically, such classifications serve as the basis for stratifying management strategies relevant to any given ecosystem{\textquoteright}s biotic and abiotic properties. The purpose for delineating resource units is to identify geographical areas at different levels of resolution that have similar capabilities and potentials for management. As soil variability is scale-dependent in both space and time, it is important to understand spatial and temporal variables controlling soil and ecosystem function at specific scales of interest. Often soil geographic models at regional and domain scales are based on up-scaled data aggregated from the downscale soil properties. Yet at macroscales, soil ecosystems are controlled by macroclimatic properties that control daily and seasonal fluxes of energy and moisture, such as latitude (variability of soil energy), distance from the sea (continentality or oceanic influences), and elevation. It is only at mesoscale and microscale levels that landform properties (such as geology and topography) modify macroclimates by regulating the intensity of other key factors important to soil formation. Although results are preliminary, we show that landscape classification models identifying regional and domain scaled soil systems should be based on the more homogeneous macroclimate variables, as these systems lay above the local modifying influences of landforms. }, author = {S. W. Salley and Joel R. Brown} } @conference {JRN54450, title = {Facilitating knowledge discovery and visualization through mining contextual data from published studies: lessons from JournalMap}, booktitle = {100th Annual Meeting of the Ecological Society of America}, year = {2015}, month = {08/2015}, publisher = {Ecological Society of America}, organization = {Ecological Society of America}, address = {Baltimore, MD}, abstract = {

Valuable information on the location and context of ecological studies are locked up in publications in myriad formats that are not easily machine readable. This presents significant challenges to building geographic-based tools to search for and visualize sources of ecological knowledge. JournalMap is a scientific literature search engine that was created to enable discovery of relevant research based on location and biophysical attributes along with traditional keyword searching. We will present approaches developed in JournalMap for mining, mapping and visualizing study location information from scientific articles using pattern recognition algorithms and crowdsourcing tools.\  IGN 6-5.

}, author = {Jason W. Karl and Jeffrey K. Gillan} } @conference {JRN54425, title = {Forecasting regional grassland and shrubland responses to directional changes in climate using multi-year dry or wet period}, booktitle = {2015 LTER All Scientists Meeting}, year = {2015}, month = {08/2015}, address = {Estes Park, CO}, abstract = {

Ecologists are being challenged to predict ecosystem responses under changing climatic conditions. Although air temperatures are increasing, the magnitude and direction of change in precipitation (increase or decrease) are uncertain for many sites. Given that water availability is the primary driver of ecosystem processes in temperate grasslands and shrublands, these uncertainties in precipitation mean that ecologists must account for both possibilities. Long-term research sites (LTER, LTAR) provide natural experiments for ecological responses that occurred historically during multi-year drought or wet periods 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 seven sites in North America where precipitation showed sequences (\> 3 years) 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 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 or the equation using individual dry years. 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 rainfall 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 drought or number of wet years can be used to explain historic patterns, such as the 1930s drought or unusual grass recovery patterns, as well as improve future predictions under directional climate change.\  Paper No. 62.

}, 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} } @proceedings {JRN54570, title = {Forecasting regional grassland and shrubland responses to directional changes in climate using multi-year dry or wet periods}, year = {2015}, month = {07/2015}, publisher = {LTER}, address = {Estes Park, Colorado}, abstract = {Ecologists are being challenged to predict ecosystem responses under changing climatic conditions. Although air temperatures are increasing, the magnitude and direction of change in precipitation (increase or decrease) are uncertain for many sites. Given that water availability is the primary driver of ecosystem processes in temperate grasslands and shrublands, these uncertainties in precipitation mean that ecologists must account for both possibilities. Long-term research sites (LTER, LTAR) provide natural experiments for ecological responses that occurred historically during multi-year drought or wet periods 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 seven sites in North America where precipitation showed sequences (> 3 years) 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 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 or the equation using individual dry years. 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 rainfall 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 drought or number of wet years can be used to explain historic patterns, such as the 1930s drought or unusual grass recovery patterns, as well as improve future predictions under directional climate change.}, 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} } @article {JRN54038, title = {Functional response of U.S. grasslands to the early 21st-century drought}, journal = {Ecology}, volume = {95}, year = {2014}, month = {08/2014}, pages = {2121-2133}, chapter = {2121}, abstract = {

Grasslands across the United States play a key role in regional livelihood and national food security. Yet, it is still unclear how this important resource will respond to the prolonged warm droughts and more intense rainfall events predicted with climate change. The early 21st-century drought in the southwestern United States resulted in hydroclimatic conditions that are similar to those expected with future climate change. We investigated the impact of the early 21st-century drought on aboveground net primary production (ANPP) of six desert and plains grasslands dominated by C4 (warm season) grasses in terms of significant deviations between observed and expected ANPP. In desert grasslands, drought-induced grass mortality led to shifts in the functional response to annual total precipitation (PT), and in some cases, new species assemblages occurred that included invasive species. In contrast, the ANPP in plains grasslands exhibited a strong linear function of the current-year PT and the previous-year ANPP, despite prolonged warm drought. We used these results to disentangle the impacts of interannual total precipitation, intra-annual precipitation patterns, and grassland abundance on ANPP, and thus generalize the functional response of C4 grasslands to predicted climate change. This will allow managers to plan for predictable shifts in resources associated with climate change related to fire risk, loss of forage, and ecosystem services.

}, keywords = {climate change, desert, extreme events, grassland production, invasive species, plains, precipitation variability, resilience, warm drought}, doi = {10.1890/13-1687.1}, url = {/files/bibliography/14-025.pdf}, author = {S. Moran and Guillermo E. Ponce-Campos and Alfredo Huete and M.P. McClaran and Yongguang Zhang and Hamerlynck, Erik and D.J. Augustine and Stacey A. Gunter and S.G. Kitchen and Debra C. Peters and Paul F. Starrs and Mariano Hernandez} } @article {JRN54164, title = {A field test of a model for the stability of androdioecy in the freshwater shrimp, Eulimnadia texana}, journal = {Journal of Evolutionary Biology}, year = {2014}, pages = {1-16}, abstract = {

The evolution of hermaphroditism from dioecy is a poorly studied transition. Androdioecy (the coexistence of males and hermaphrodites) has been suggested as an intermediate step in this evolutionary transition or could be a stable reproductive mode. Freshwater crustaceans in the genus Eulimnadia have reproduced via androdioecy for 24+ million years and thus are excellent organisms to test models of the stability of androdioecy. Two related models that allow for the stable maintenance of males and hermaphrodites rely on the counterbalancing of three life history parameters. We tested these models in the field over three field seasons and compared the results to previous laboratory estimates of these three parameters. Male and hermaphroditic ratios within years were not well predicted using either the simpler original model or a version of this model updated to account for differences between hermaphroditic types (\‘monogenic\’ and \‘amphigenic\’ hermaphrodites). Using parameter estimates of the previous year to predict the next year\’s sex ratios revealed a much better fit to the original relative to the updated version of the model. Therefore, counter to expectations, accounting for differences between the two hermaphroditic types did not improve the fit of these models. At the moment, we lack strong evidence that the long-term maintenance of androdioecy in these crustaceans is the result of a balancing of life history parameters; other factors, such as metapopulation dynamics or evolutionary constraints, may better explain the 24+ million year maintenance of androdioecy in clam shrimp.

}, keywords = {clam shrimp, Eulimnadia, freshwater shrimp, hermaphroditism, inbreeding depression, mating system, self-fertilization, sexual systems, Study 204}, doi = {10.1111/jeb.12459}, author = {Weeks, S. C. and Benvenuo, C. and Reed, S. K. and Duff, R. J. and Duan, Z.-H. and David, P.} } @book {49877, title = {A Field Guide to Pedoderm and Pattern Classes Version 2.3}, year = {2012}, pages = {74}, publisher = {USDA-ARS Jornada Experimental Range}, organization = {USDA-ARS Jornada Experimental Range}, type = {field guide}, address = {Las Cruces, NM}, abstract = {Pedoderm and Pattern Classes (PPCs) describe the spatial arrangement of plants, the soil pedoderm (i.e., the air-soil interface) and soil redistribution. PPCs provide a record of soil surface features and plant patterns that influence ecosystem function and complement snapshot observations of plant community composition and soil profiles. In essence, PPCs provide a simple language to describe soil surface features and plant patterns much in the same way we recognize plant communities or soil types using standardized names. PPCs have categorical or ordinal values and are designed to be assessed quickly within field plots during inventory, soil survey, or when characterizing site conditions of monitoring plots. The class values provide a record of soil surface features and plant patterns that affect the site\&$\#$39;s ability to respond to management actions, restoration, and natural drivers. To date, obtaining information about these types of attributes has required highly technical and/or time-intensive procedures, so soil surface and plant pattern data have not been regularly collected. We developed PPCs to help remedy this limitation. PPCs closely correspond to several of the indicators described in Interpreting Indicators of Rangeland Health (IIRH; Pellant et al., 2005) and Landscape Function Analysis (LFA; Tongway and Hindley 2004). Unlike IIRH, PPCs are not based on deviation from site potential, but rather describe existing conditions. Furthermore, PPCs integrate observations of multiple attributes that are dealt with individually in IIRH and LFA (such as pedestals, water flow patterns, rills and coppicing) to arrive at a single class value. Thus, a trained observer can evaluate a site quickly without rating and interpreting numerous individual indicators. PPCs are especially useful when multiple observations must be gathered quickly over extensive areas.}, keywords = {field guide, pattern classes, pedoderm}, isbn = {0-9755552-4-3}, url = {files/FieldGuidePedodermPattern.pdf}, author = {Laura M. Burkett and Brandon T Bestelmeyer and A.J. Tugel} } @article {49938, title = {Forest structure and aboveground biomass in the southwestern United States from MODIS and MISR}, journal = {Remote Sensing of Environment}, volume = {115}, year = {2011}, month = {05/2011}, pages = {2943-2953}, chapter = {2943}, abstract = {Red band bidirectional reflectance factor data from the NASA MODerate resolution Imaging Spectroradiometer (MODIS) acquired over the southwestern United States were interpreted through a simple geometric\–optical (GO) canopy reflectance model to provide maps of fractional crown cover (dimensionless), mean canopy height (m), and aboveground woody biomass (Mg ha-1) on a 250 m grid. Model adjustment was performed after dynamic injection of a background contribution predicted via the kernel weights of a bidirectional reflectance distribution function (BRDF) model. Accuracy was assessed with respect to similar maps obtained with data from the NASA Multiangle Imaging Spectroradiometer (MISR) and to contemporaneous US Forest Service (USFS) maps based partly on Forest Inventory and Analysis (FIA) data. MODIS and MISR retrievals of forest fractional cover and mean height both showed compatibility with the USFS maps, with MODIS mean absolute errors (MAE) of 0.09 and 8.4 m respectively, compared with MISR MAE of 0.10 and 2.2 m, respectively. The respective MAE for aboveground woody biomass was ~10 Mg ha-1, the same as that from MISR, although the MODIS retrievals showed a much weaker correlation, noting that these statistics do not represent evaluation with respect to ground survey data. Good height retrieval accuracies with respect to averages from high resolution discrete return lidar data and matches between mean crown aspect ratio and mean crown radius maps and known vegetation type distributions both support the contention that the GO model results are not spurious when adjusted against MISR bidirectional reflectance factor data. These results highlight an alternative to empirical methods for the exploitation of moderate resolution remote sensing data in the mapping of woody plant canopies and assessment of woody biomass loss and recovery from disturbance in the southwestern United States and in parts of the world where similar environmental conditions prevail. \© 2011 Elsevier Inc. All rights reserved.}, keywords = {aboveground biomass, article, canopy reflectance model, carbon, Earth Observing System, forest structure, journal, MISR, model, modeling, MODIS, remote sensing}, doi = {10.1016/j.rse.2010.08.031}, url = {/files/bibliography/11-033.pdf}, author = {M. Chopping and C. Schaaf and F. Zhao and Zhongwu Wang and Nolin, Anne W. and Moisen, Gretchen G. and J. V. Martonchik and Michael Bull} } @article {49969, title = {Foraging behavior of heritage versus recently introduced herbivores on desert landscapes of the American Southwest}, journal = {Ecosphere}, volume = {2}, year = {2011}, month = {05/2011}, pages = {1-14}, chapter = {Article 57}, abstract = { Since the 1800s managed grasslands and shrublands of the arid American Southwest have been grazed predominantly by cattle originally bred for temperate climates in northern Europe. A heritage breed, the criollo cattle, has survived in northern Mexico for more than 400 years under desert-like conditions of low and variable rainfall, hot temperatures in the growing season, and both spatially and temporally scarce levels of primary production. We tested the hypothesis that the heritage breed has a broader spatial foraging distribution under harsh environmental conditions, and that its distribution is driven by environmental variables which differ from those that control the distribution of the introduced European breed. Movements of individual criollo and Angus breed animals were monitored autonomously in the northern Chihuahuan desert of southern New Mexico, USA. Georeferenced foraging locations acquired at 5-minute intervals for each animal were fit to a logistic regression using environmental factors as predictors. In the spring, when forage availability was high and more uniformly distributed across the landscape, animal foraging patterns were similar for both breeds. In the fall when forage availability was low and non-uniformly distributed, the two breeds exhibited very different foraging patterns: heritage animals foraged across a much larger spatial extent whereas their domestic counterparts remained in close proximity to the permanent source of water. These differences in foraging behavior driven by environmental variables have important implications for sustainability of rangelands in spatially and temporally variable environments. Heritage breeds of animals that are generalist foragers during unfavorable conditions can reduce environmental impacts compared to more recently introduced breeds.}, keywords = {Chihuahuan Desert, criollo cattle, GPS monitoring, herbivory, landscape foraging patterns, resource selection functions}, doi = {doi:10.1890/ES11-00021.1}, url = {/files/bibliography/11-009.pdf}, author = {H. Raul Peinetti and E.L. Fredrickson and Debra C. Peters and Andr{\'e}s F. Cibils and Roacho-Estrada, J.O. and Andrea S. Laliberte} } @conference {JRN54461, title = {Free-ranging cow behavior pre and post-weaning}, booktitle = {63rd Society for Range Management Annual Meetings}, year = {2010}, month = {02/2010}, publisher = {Sociiety for Range Management}, organization = {Sociiety for Range Management}, address = {Denver, CO}, abstract = {

The optimum husbandry of free-ranging cattle requires not only nutritional knowledge but also an understanding of how to manage and use behavioral information.\  With the advent of global positioning technology (GPS) it is now possible to monitor animal travel with relative ease over extended periods of time without the observer influencing the observation.\  Between March and April 2009 five cows in each of two similar large ({\textthreesuperior} 433 ha) arid rangeland pastures were individually monitored at a 1 Hz rate before as well as following weaning.\  The ten cows ranged in age between three and fifteen years with six of the cows suckling male calves while the remaining four calves were female.\  Accelerometer and magnetometer data used to quantify foraging and non-foraging behaviors together with animal travel will be discussed in light of directional virtual fencing (DVFTM) hardware and software that was used to obtain the data.

}, author = {D.M. Anderson and Craig Winters and Marek Doniec and D. Rus and B. Nolen} } @proceedings {50016, title = {Field validation of biomass retrieved from Landsat for rangeland assessment and monitoring}, year = {2010}, month = {July 25-30, 2010}, publisher = {International Symposium on Geoscience and Remote Sensing}, address = {Honolulu, HI}, abstract = {

Measures of terrestrial biomass that are accurate and repeatable are important to monitoring and modeling productivity in the world{\textquoteright}s grassland and savanna (i.e., rangeland) ecosystems. Remote sensing offers potential to characterize seasonal changes in biomass in a consistent non-destructive manner. We capitalized on long-term measurements of aboveground biomass at the Jornada Basin (JRN) Long-Term Ecological Research site in the northern Chihuahuan desert. We sought to answer two questions (1) Does Landsat 5 Thematic Mapper (TM) imagery serve as a reliable and accurate proxy for vegetation biomass in this highly heterogeneous arid ecosystem? and (2) How do differences in vegetation structure influence biomass/SVI relationships? For this pilot study, seven images corresponding to biomass sampling dates from Nov 2006 to Nov 2008 were selected from the Landsat image archive to relate biomass to image-based indicators of vegetative vigor. TM images were processed to yield top of atmosphere radiance values corrected for atmospheric effects using the image-based COST method. We evaluated the performance of four SVIs normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), soil-adjusted vegetation index (SAVI), and modified soil-adjusted vegetation index (MSAVI2). To facilitate comparison of results from Landsat and the MODIS sensor in this arid ecosystem, we report values for EVI. EVI values are reported as the mean of 25 TM pixel values corresponding to the 150-m X 150-m area centered on the fifteen 0.5-ha study sites. Relationships between EVI and biomass were linear and consistent for sites within each of five vegetation communities (i.e. creosote, mesquite, tarbush, grassland, and playas). Field measurements of biomass ranged widely over time and across sites (0 to 422.2 g/m2). EVI tracked changes in biomass reasonably well with R2 values ranging from 0.238 (for playa sites) to 0.789 (for mesquite sites). EVI exhibited a low dynamic range in values across large differences in plant biomass. Grassland EVI responses do not always clearly reflect changes in biomass which may be due to the prominence of senescent vegetation at grassland and playa sites or confounded by the prominence of bare soil in arid ecosystems. On-going analyses will evaluate the performance of other SVIs. The range in physiognomy and productivity at the JRN is well-suited for field validation exercises for biophysical parameters retrieved via remote sensing. Accurate and robust relationships between spectral vegetation indices derived from freely available satellite imagery and field measurements of biomass are powerful tools for monitoring landscape condition in arid and semi-arid rangelands.

}, url = {/files/bibliography/10-028.pdf}, author = {Dawn M. Browning and Debra C. Peters and Caitriana Steele and A. Rango} } @article {50033, title = {Fine gravel controls hydrologic and erodibility responses to trampling disturbance for coarse-textured soils with weak cyanobacterial crusts}, journal = {CATENA}, volume = {83}, year = {2010}, month = {08/2010}, pages = {119-126}, chapter = {119}, abstract = {We compared short-term effects of lug-soled boot trampling disturbance on water infiltration and soil erodibility on coarse-textured soils covered by a mixture of fine gravel and coarse sand over weak cyanobacterially-dominated biological soil crusts. Trampling significantly reduced final infiltration rate and total infiltration and increased sediment generation from small (0.5 m2) rainfall simulation plots (p\<0.01). Trampling had no effect on time to runoff or time to peak runoff. Trampling had similar effects at sites with both low and very low levels of cyanobacterial biomass, as indicated chlorophyll a concentrations. We concluded that trampling effects are relatively independent of differences in the relatively low levels of cyanobacterial biomass in this environment. Instead, trampling appears to reduce infiltration by significantly reducing the cover of gravel and coarse sand on the soil surface, facilitating the development of a physical crust during rainfall events. The results of this study underscore the importance of carefully characterizing both soil physical and biological properties to understand how disturbance affects ecosystem processes.}, keywords = {arid soils, Biological soil crusts, erosion, hydrology, land degradation, recreation}, doi = {10.1016/j.catena.2010.08.007}, url = {/files/bibliography/10-032.pdf}, author = {Jeffrey E. Herrick and Justin Van Zee and Jayne Belnap and J. Johansen} } @proceedings {50045, title = {Feature selection methods for object-based classification of sub-decimeter resolution digital aerial imagery}, volume = {XXXVIII}, year = {2010}, pages = {4/C7}, address = {Ghent, Belgium}, abstract = {Due to the availability of numerous spectral, spatial, and contextual features, the determination of optimal features and class separabilities can be a time consuming process in object-based image analysis (OBIA). While several feature selection methods have been developed to assist OBIA, a robust comparison of the utility and efficiency of approaches could facilitate broader application. In this study, we tested feature selection methods and assessments of class separability for object-based classifications of arid land vegetation in the southwestern U.S. using sub-decimeter digital aerial imagery with a 6 cm ground resolved distance. Using Definiens Developer software, we evaluated 1) classification tree analysis (CTA), 2) feature space optimization (FSO), and 3) SEparability and THreshold (SEaTH). We assessed strengths, weaknesses and best uses for each approach using the criteria of ease of use, ability to rank and/or reduce input features, ability to obtain feature thresholds and class separation distances, and underlying statistical assumptions. We conclude that CTA is best suited for reducing a large number of input features, either for nearest neighbor classification or for deriving rules for rule-based classification. FSO is most appropriate for determining a suitable group of features relatively quickly, because it operates within the Definiens software. However, the features are not ranked and feature thresholds cannot be determined. SEaTH interfaces well with outputs from Definiens and is most appropriate for ranking input features based on class separation distances for two-class comparisons, but has the disadvantage of assuming normality, unlike the non-parametric CTA. All methods offered an objective approach for determining suitable features for classifications of hyperspatial aerial imagery. Limitations, assumptions, and appropriate uses for this and other datasets are discussed.}, keywords = {accuracy, aerial photography, classification, feature selection, high resolution, object-based image analysis (OBIA), vegetation}, url = {/files/bibliography/10-048.pdf}, author = {Andrea S. Laliberte and Dawn M. Browning and A. Rango} } @conference {50066, title = {Free-ranging cow behavior pre and post-weaning}, booktitle = {Society for Range Management Meeting Abstracts}, year = {2009}, abstract = {The optimum husbandry of free-ranging cattle requires not only nutritional knowledge but also an understanding of how to manage and use behavioral information. With the advent of global positioning technology (GPS) it is now possible to monitor animal travel with relative ease over extended periods of time without the observer influencing the observation. Between March and April 2009 five cows in each of two similar large (? 433 ha) arid rangeland pastures were individually monitored at a 1 Hz rate before as well as following weaning. The ten cows ranged in age between three and fifteen years with six of the cows suckling male calves while the remaining four calves were female. Accelerometer and magnetometer data used to quantify foraging and non-foraging behaviors together with animal travel will be discussed in light of directional virtual fencing (DVF{\texttrademark}) hardware and software that was used to obtain the data.}, keywords = {free-ranging}, author = {D.M. Anderson and R. Libeau and D. Rus and Detweiler, C. and B. Nolen} } @article {50083, title = {Field validation of 1930s aerial photography: What are we missing?}, journal = {Journal of Arid Environments}, volume = {73}, year = {2009}, month = {06/2009}, pages = {844-853}, chapter = {844}, abstract = {

Aerial photography from the 1930s serves as the earliest synoptic depiction of vegetation cover. We generated a spatially explicit database of shrub (Prosopis velutina) stand structure within two 1.8 ha field plots established in 1932 to address two questions: (1) What are the detection limits of panchromatic 1936 aerial photography?, and (2) How do these influence P. velutina biomass estimates? Shrub polygons were manually digitized on 1936 imagery and linked to 1932 field measurements of P. velutina canopy area. Aboveground 1932 P. velutina biomass was estimated using a site-specific allometric relationship for field-measured canopy area. Shrub canopy detection limits on the 1936 imagery were comparable to those reported for contemporary imagery. Based on a conservative shrub size detection threshold of 3.8 m2, 5.8\% of P. velutina biomass was missed. Spatial resolution (0.6 vs. 1.0 m) did not influence detection limits, but the overall accuracy of shrub cover estimates was greater on 1.0 m images. Presence of the sub-shrub Isocoma tenuisecta may also have significantly influenced estimates of P. velutina canopy area. These analyses illustrate the importance of standardizing aerial photo interpretation protocols, accounting for uncertainty estimating shrub biomass, and caution species-specific interpretations for historic aerial photography.

}, keywords = {aboveground woody biomass, detection limites, error assessment, historid aerial photography, land cover, panchromatic, retrospective ground truth, retrospective mapping, Santa Rita, Sonoran Desert}, doi = {10.1016/j.jaridenv.2009.04.003}, url = {/files/bibliography/09-019.pdf}, author = {Dawn M. Browning and Steven R. Archer and Byrne, A.T.} } @article {50108, title = {Fire in Chihuahuan Desert grassland: Short-term effects on vegetation, small mammal populations, and faunal pedoturbation}, journal = {Journal of Arid Environments}, volume = {73}, year = {2009}, month = {07/2009}, pages = {1029-1034}, chapter = {1029}, abstract = {A prescribed burn resulted in significant decreases in canopy cover of the grasses: Bouteloua eriopoda, Sporobolus flexuosus, and Aristida purpurea. One year post-burn, basal cover of B. eriopoda remained significantly lower in burned patches than in unburned areas but there were no differences in basal cover of the other perennial grasses. Only one species of the 14 summer annual species occurred in both burned and unburned plots. There were six species of spring annuals in burned patches but no spring annuals in the unburned grassland ten months post-burn. Fire killed 100\% of the snakeweed shrubs (Gutierrezia sarothrae), 77\% of the Ephedra torreyana shrubs, and 36\% of the Yucca elata. All mesquite shrubs that were top-killed by fire, resprouted one month post-burn. Fire had no effect on abundance and species richness of rodents. There were fewer wolf spider, Geolycosa spp. burrows in burned areas than in unburned grassland. The area and volume of soil in termite galleries and sheeting were significantly larger in the unburned grassland than in the burned areas.}, keywords = {aggregate stability, Bouteloua eriopoda, cache pits, heteromyid rodents, resilience, sporobolus spp.}, doi = {10.1016/j.jaridenv.2009.04.016}, url = {/files/bibliography/09-021.pdf}, author = {Aaron Killgore and E. Jackson and Walter G. Whitford} } @article {50128, title = {First Flight, New Test Center open airspace to UAS research}, volume = {Spring}, year = {2009}, note = {Magazine article promoting UAV research w/PSL}, month = {2009}, pages = {18-19}, publisher = {New Mexico State University}, url = {http://researchmag.nmsu.edu/2009_SP/feature_first.html}, author = {Pehr, D.J.} } @article {50149, title = {Faunalpedturbation effects of soil microarthropods in the Negev Desert}, journal = {Journal of Arid Environments}, volume = {73}, year = {2009}, month = {2009}, pages = {907-911}, chapter = {907}, abstract = {

Soil microarthropod communities in seed-harvester ant-nest (Messor spp.) soils and pits excavated by porcupines (Hystrix indica) were examined on a hill-slope catena in the Negev Desert to test the hypothesis that animal-produced soil disturbances increase abundance and diversity of soil biota. There were significantly fewer arthropods and lower taxonomic diversity of soil microarthropods at the top and mid-slope locations, with no consistent patterns of abundance between cool-wet and hot-dry seasons. Some prostigmatids, cryptostigmatids, and other arthropods in ant-nest, porcupine-pit, and undisturbed soils were more abundant in wet than dry seasons at some locations but more abundant in the hot-dry season at other locations and sample sites. Seven prostigmatid mite families that were relatively abundant in undisturbed soils were absent or of low abundance in ant-nest modified and porcupine-pit soils at mid- and low-slope catena locations. The data result in rejection of the hypothesis. However, the significant effects of topographic position on the catena on soil microarthropod communities emphasize the importance of examining broad spatial patterns and temporal variation before making generalizations about the effects of ecological engineers on arid ecosystem structure and function.

}, keywords = {catena, cryptostigmatids, ecological engineers, prostigmatids, soil mites, taxonomic diversity, taxonomic richness}, doi = {10.1016/j.jaridenv.2009.04.001}, url = {/files/bibliography/09-015.pdf}, author = {Ukabi, S. and Walter G. Whitford and Yosef Steinberger} } @proceedings {50158, title = {Fluorometry - an evolving methodology for range animal ecologist}, volume = {1}, year = {2008}, month = {July 1, 2008}, pages = {572}, publisher = {Guangdong People{\textquoteright}s Publishing House}, address = {Hohhot, China}, abstract = {Fluorometry is an optically based technique that has only recently (1996) been shown to be useful in identifying pre-as well as post-digested plant material found in free-ranging animal diets. This article traces the evolution of this methodology as a tool to determine the botanical composition, a key to understanding and subsequently managing range animal ecology. Several instruments have successfully been used as sources of illumination including a neodymium:yttrium aluminum garnet laser, Xenon-arc lamps and most recently light emitting diodes (LED{\textquoteright}s). Furthermore, several organic and inorganic solvents have been used to extract fluorophores principally in the blue, green and red regions of the visible spectrum. The resulting data from the emission spectrums produced have been analyzed in a variety of ways to establish statistical differences among plant species and mixtures with multi-way principal component analysis (MPCA) appearing to hold the greatest promise in teasing apart differences among species and specie mixtures that have visually similar spectral signatures.}, keywords = {digested, fluorometry, free-ranging}, author = {D.M. Anderson and G.D. Rayson} } @conference {50250, title = {Feedbacks between aeolian processes, vegetation productivity, and nutrient flux in deserts}, booktitle = {Geological Society of America Meetings}, series = {Geological Society of America Meetings}, year = {2008}, abstract = {Wind is a key abiotic factor that influences the dynamics of arid and semiarid systems. A series of experiments and models will be presented that show the important feedbacks that exist between Aeolian processes and biotic process in deserts. Wind impacts vegetation by both changing the composition of the soils, mainly by winnowing fines from erosional areas and redeposition of fines in deposition areas, and by direct physical effects on plants. The former leads to significant loss and redistribution of soil organic matter and plant nutrients as well as the disruption of nutrient cycling process. The latter leads to burial, pedestaling, leaf stripping and branch abrasion that lead to increased plant mortality. There is significant evidence that this leads to state changes in deserts, namely replacement of grasses by shrubs, which in turn create landscapes that are far larger emitters of dust. Changes in aridity have, in the past, caused changes variations in dust emission associated with vegetation state changes and, models suggest, aeolian processes will be increasingly important in vegetation change and dust emissions in deserts.}, keywords = {abstract, aeolian, arid, biotic, semiarid, wind}, author = {Gregory S. Okin and Junran Li and Lorelei Alvarez and Debra C. Peters and Paolo D{\textquoteright}Odorico} } @proceedings {50310, title = {Fungal genomes that influence basic physiological processes that enhance survival of black grama and fourwing saltbush in arid southwestern rangelands}, number = {RMRS-P-47}, year = {2007}, month = {August 10-12, 20}, pages = {123-131}, address = {Lubbock, TX}, abstract = {Symbiotic fungi confer multiple benefits such as enhanced photosynthetic rates and drought tolerance in host plants. Shrubs and grasses of southwestern deserts are colonized by symbiotic fungi that cannot be removed by conventional sterilization methods. These fungi were extensively studied in Bouteloua eriopoda (Torr.) Torr. and Atriplex canescens (Pursh) Nutt. over a wide range of locations and environmental conditions. Fungi were intrinsically integrated with cells, tissues, and regenerated plant cultures. These composite plant-fungus organisms are comprised of more than one fungal species. Fungal association with photosynthetic cells, accumulation of lipids provided evidence for carbon management. Fungal biofilms that coat cells, tissues, roots, and leaves suggest that they protect cells, roots, and leaves from direct exposure to stressed environments. Associations with vascular tissues suggested a role in resource transport. Association with stomata indicates an influence in gas exchange, photosynthesis, and evapotranspiration. Transfer of fungal endophytes from native plants to nonhost plants resulted in substantial modifications in root, shoot morphology and biomass, chlorophyll content, and fruiting. Host plants are modified by fungi at the genetic, cellular, and physiological levels and positively enhance ecological fitness.}, keywords = {associations, composite, fungi, manipulation, native plants}, url = {http://www.fs.fed.us/rm/pubs/rmrs_p047/rmrs_p047_123_131.pdf}, author = {J.R. Barrow and M.E. Lucero and P. Osuna and Reyes, I. and Aaltonen, R.E.} } @conference {50324, title = {The functional role of carbonate-cemented soil horizons in desert ecosystems: Spatial and temporal dynamics of plant water availability}, booktitle = {Ecological Society of America }, year = {2007}, month = {August 5-10, 200}, pages = {COS 147-6}, address = {San Jose, CA}, abstract = {In water limited ecosystems, soil profile characteristics can control plant community composition and production through their effects on spatial and temporal patterns of plant available water. Little is known, however, about water availability in soil horizons cemented with carbonates (petrocalcic horizons), which occur extensively in arid ecosystems. To investigate petrocalcic water retention and dynamics, a series of replicated experiments at multiple spatial scales was conducted in a mixed shrub-grass community in southern New Mexico, USA. A laboratory study was conducted evaluating the water holding capacity of a variety of petrocalcic material. Petrocalcic temporal water availability and dynamics were monitored in two multiyear field studies: a pasture scale study comparing water availability across soils with differing degrees of petrocalcic development and a companion patch-interspace scale study investigating soil-water dynamics associated with woody shrub encroachment in a petrocalcic soil. Petrocalcic available water holding capacities were up to four times those of the sandy loam parent material. Calcic and petrocalcic horizons retained much greater amounts of available soil water for several months following above-normal winter and summer precipitation than similar depths in a non-carbonate sand. The companion study in the petrocalcic soil showed that unvegetated interspaces absorbed significantly more soil water during a wet winter and retained more available soil water into the spring than soils under shrubs. Wetting and drying dynamics indicate petrocalcic horizons release stored water into the grass rooting zone. Furthermore, patterns of water availability suggest soils with shallow petrocalcic horizons are beneficial to the establishment and persistence of grasses.}, keywords = {carbonate-cemented, spatial, temporal}, author = {Danielle Duni and Jeffrey E. Herrick and Curtis H. Monger} } @proceedings {50374, title = {Future climate change impacts on New Mexico{\textquoteright}s mountain sources of water}, year = {2007}, month = {11/2007}, pages = {CDROM}, publisher = {Water Resources Research Institute}, edition = {2008}, address = {Santa Fe, New Mexico}, abstract = {The Rio Grande is one of the most important rivers in the western U.S. and is representative of mountain snowmelt basins in arid and semiarid regions around the world. As is true for many arid and semiarid rivers, the total available water supply is already exceeded by water demands. Dependable water supply comes from high elevation snowpacks that contribute 50-75\% of the annual streamflow. Summer rainfall, which is sporadic and frequently of high intensity, supplies the remaining streamflow. Rapid changes in many mountain regions of the world are being experienced due to global climate change and anthropogenic effects. New Mexico water managers and decision makers urgently need knowledge of the potential effects of climate change on the state{\textquoteright}s water resources. Research being done addresses this topic through the development of improved sensing and modeling infrastructure to estimate future changes in water supply from snow-dominated headwater basins. Existing climate change scenarios generated by general circulation and regional climate models are being utilized to develop reasonable forcing variables for basin hydrologic models which will be used as decision-making tools to evaluate the impact of climate changes in the basin. The hydrologic models being employed include the basin-wide Semi-distributed Land Use and Runoff Processes (SLURP) model that serves to integrate models operating on sub-catchments throughout the Rio Grande basin. The Snowmelt Runoff Model (SRM) is used to simulate and forecast flow in the mountainous snowmelt sub-basins and is directly linked to SLURP. SRM also has a formalized climate change algorithm useful in this study. Operating on smaller Rio Grande sub-basins, the TIN-based Real-Time Integrated Basin Simulator (tRIBS) is a distributed hydrologic model for streamflow forecasting and better understanding of processes active in producing runoff. Finally, the RioGEM hydro-economics model is being used to evaluate the benefits from different management strategies in response to hydrologic changes generated by SLURP, SRM, and tRIBS. The results of this project will address the important problem of how global warming will reduce our already overcommitted water supply and what economic and societal impacts will result.}, keywords = {arid, climate, New Mexico, proceedings, Rio Grande, semiarid rivers, sources, water}, url = {/files/bibliography/08-054.pdf}, author = {A. Rango and Enrique Vivoni and Gutzler, D. and Hurd, B. and Brandon T Bestelmeyer} } @article {50419, title = {Fragmentation Effects on Soil Aggregate Stability in a Patchy Arid Grassland}, journal = {Rangeland Ecology and Management}, volume = {59}, year = {2006}, month = {July 2006}, pages = {406-415}, abstract = {Soil aggregate stability (AS) has been promoted as a primary indicator of soil-surface function and a key metric in state-and-transition models. There are few studies, however, that relate indices of AS to the process of grassland degradation. In a Chihuahuan Desert rangeland, we measured variation in AS across vegetated-bare patch boundaries within six plot types reflecting a hypothesized fragmentation/transition sequence. We also examined wetting front depth and pH along this sequence. We found that AS exhibited consistent and interpretable variation across the patch boundaries of the different plot types. Average AS was highest in grass patches adjacent to small to medium-sized (0.5-1.5 m) bare patches and was low in grass patches adjacent to large (\> 3 m) bare patches. AS of bare ground was also lowest when bare patches in continuous grassland were large and when bare ground formed an interconnected matrix. Wetting depth after a large storm decreased and pH increased along the fragmentation sequence. The results suggest that AS has interpretable relationships with grassland fragmentation and transitions among states. Careful attention to patchiness within states and stratification, however, is important and simple classifications of strata, such as \“bare interspace\” and \“plant\”, may not be sufficient to document variation in soil function. http://www.bioone.org/perlserv/?request=get-pdf\&doi=10.2111\%2F05-180R1.1}, keywords = {aggregate stability, soil-surface, state-and-transition}, url = {/files/bibliography/06-027.pdf}, author = {Brandon T Bestelmeyer and J.P. Ward and Jeffrey E. Herrick and A.J. Tugel} } @inbook {50486, title = {A Framework and Methods for Simplifying Complex Landscapes to Reduce Uncertainty in Predictions}, booktitle = {Scaling and Uncertainty Analysis in Ecology: Methods and Applications}, year = {2006}, month = {2006}, pages = {131-146}, publisher = {Springer, Dordrecht}, organization = {Springer, Dordrecht}, address = {The Netherlands}, abstract = {

Many of our most pressing ecological problems, such as the conservation of biodiversity, spread of invasive species, patterns in carbon sequestration, and impacts of disturbances (e.g., fire) must be addressed at the landscape scale (see Law et al., Chapter 9, Groffman et al., Chapter 10, Urban et al., Chapter 13). However, much of our information about these problems comes from plot-scale studies that must be extrapolated to the landscape. Because landscapes are complex, this extrapolation is not always straightforward or easy to accomplish (Turner et al. 1989a, Wu and Li, Chapter 2, Braford and Reynolds,Chapter 6). Landscape complexity results from the processes, factors, and their interactions that occur across a range of spatial and temporal scales. The problem is further complicated by the presence of contagious or neighborhood processes that connect different parts of a landscape. Dispersal of seeds by wind or animals, fire, and erosion and deposition of soil and nutrients by wind and water are examples of spatial or contagious processes that influence ecosystem dynamics. Landscape complexity makes it difficult to understand and predict ecosystem dynamics across spatial scales with high levels of confidence or certainty. Our goal is to develop a conceptual framework and operational approach to simplifying complex landscapes in order to minimize both prediction errors and costs associated with measurement, analysis, and prediction.

}, keywords = {ecosystems, linear, spatial temp oral heterogeneous}, doi = {10.1007/1-4020-4663-4_7}, url = {/files/bibliography/06-051.pdf}, author = {Debra C. Peters and Jin Yao and L. Huenneke and Kris Havstad and Jeffrey E. Herrick and A. Rango and W. H. Schlesinger} } @inbook {50490, title = {Future Directions in Jornada Research: Applying an Interactive Landscape Model to Solve Problems}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {369-386}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {18}, address = {New York, NY}, abstract = {In this book chapter, we propose a new model of arid and semiarid landscapes that focuses explicitly on the processes and properties that generate spatial variation in ecosystem dynamics. We are specifically interested in three interrelated aspects of landscapes: (1) feedbacks among plants, animals, and soils generated from interactions among biotic processes, a heterogeneous physical template, and the disturbance regime across a range of spatial and temporal scales, (2) neighborhood or contagious processes that generate fluxes and flows within and among spatial units, and (3) the landscape context and the condition of the study area of interest relative to its surroundings that modifies the transfers of materials. We first describe our spatially interactive model and compare it to previous models then introduce an approach to identify the landscape locations where spatial processes and information are needed in order to understand and predict ecosystem dynamics. The local, regional, and global implications of our interactive landscape model are also discussed.}, keywords = {Chihuahuan Desert, Jornada Basin, LTER, synthesis book}, url = {/files/bibliography/06-069.pdf}, author = {Debra C. Peters and W. H. Schlesinger and Jeffrey E. Herrick and L. Huenneke and Kris Havstad}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @article {50517, title = {The future of vascular plant diversity under four global scenarios}, journal = {Ecology and Society}, volume = {11}, number = {2}, year = {2006}, note = {//Other//LTER-V//entered 08/15/2007}, month = {2006}, pages = {19 pages}, abstract = {

Biodiversity is of crucial importance for ecosystem functioning and human well-being. Using quantitative projections of changes in land use and climate from the four Millennium Ecosystem Assessment (MA) scenarios, we project that reduction of habitat by year 2050 will result in a loss of global vascular plant diversity ranging from 7{\textendash}24\% relative to 1995, after populations have reached equilibrium with the reduced habitat. This range includes both the impact of different scenarios and uncertainty in the SAR relationship. Biomes projected to lose the most species are warm mixed forest, savannahs, shrub, tropical forest, and tropical woodlands. In the 2000{\textendash}2050 period, land-use change contributes more on a global scale to species diversity loss than does climate change, 7{\textendash}13\% vs. 2{\textendash}4\% loss at equilibrium for different scenarios, respectively. However, after 2050, climate change will become increasingly important.

}, keywords = {article, biodiversity scenarios, journal, model,, model, biodiversity scenarios, model, MA, model, Millenium Ecosystem Assessment}, doi = {10.5751/ES-01818-110225 }, url = {files/bibliography/JRN00462.pdf}, author = {Detlef P. Van Vuuren and O. E. Sala and Pereira, Henrique M.} } @article {50621, title = {Flocks and herds or flerds--the choice is yours}, journal = {Grassroots, Newsletter of the Grassland Society of Southern Africa}, volume = {14}, number = {2}, year = {2004}, month = {June 2004}, pages = {16-22}, abstract = {A novel approach for managing mixed species stocking groups involves bonding small ruminants (sheep and goats) to cattle; so, when the animal species are put into a pasture, they remain in close proximity to each other, forming what has been termed a flerd. This close association offers several management benefits, including: protection of the smaller ruminants from canine predation, ease in locating animals at pasture, reducing the need for fencing and utilizing the landscape more uniformly than do flocks and herds. The major emphasis of the manuscript is presenting a {\textquoteright}how to{\textquoteright} approach to creating and maintaining flerds.}, keywords = {bonding, cattle, creating and maintaining, flerds, flocks, herds, ruminants}, url = {/files/bibliography/04-080.pdf}, author = {D.M. Anderson} } @article {50629, title = {Fungal endophytes intrinsically associated with micropropagated plants regenerated from native Bouteloua eriopoda Torr. and Atriplex canescens (Pursh) Nutt.}, journal = {In Vitro Cellular and Developmental Biology-Plant}, volume = {40}, number = {6}, year = {2004}, month = {November 1, 2004}, pages = {608-612}, abstract = {Black grama (Bouteloua eriopoda) and fourwing saltbush (Atriplex canescens) are important grass and shrub species in arid rangelands of the northern Chihuahuan Desert. They are naturally colonized by dark septate endophytic fungi that cannot be eliminated by seed disinfestation. Plants were regenerated from both species and appeared to be fungus free in axenic cultures. Analysis of callus and regenerated plants of both species using dual staining with light and scanning electron microscopy revealed fungal endophytes intrinsically associated with cells, roots and leaves of regenerated plants that are also associated with native plants. Fungal layers and biofilms prevent direct exposure of callus, root or leaf tissues to the external environment. Micropropagation is a valuable tool for identifying key fungal endophytes that enhance drought tolerance in native desert plants.}, keywords = {arid, biofilms, drought, mycorrhizae, symbiosis}, url = {/files/bibliography/04-008.pdf}, author = {J.R. Barrow and P. Osuna-Avila and I. Reyes-Vera} } @conference {50627, title = {Fungal genomes that influence basic physiological processes that enhance survival of black grama and forwing saltbush in arid Southwestern rangelands}, booktitle = {13th Wildland Shrub Symposium, Shrubland Dynamics: Fire and Water}, year = {2004}, month = {August 10-12, 20}, address = {Lubbock, TX}, abstract = {Symbiotic fungi are generally known to enhance photosynthetic rates and drought tolerance in host plants, but mechanisms are currently unresolved. Shrubs and grasses of southwestern deserts are colonized by symbiotic fungi that cannot be removed by conventional sterilization methods. These fungi were extensively studied in native plants over a wide range of locations and environmental conditions. Fungi associated with native plants were also found to be intrinsically integrated with cells, tissues and regenerated plant cultures. Native grasses and shrubs were found to be composite plant-fungus organisms comprised of at least two fungal species. It is suggested that these inherent associations modify their hosts at the genetic, cell and physiological levels and positively enhance ecological fitness. Colonization of photosynthetic cells, encapsulation of chloroplasts and accumulation of lipids provided evidence for host modification and performance. Carbon management is suggested by the substantial quantities of high energy lipids that are stored and transported in sieve elements. Lipids converted to biofilms protected cells, tissues, roots and leaves from direct exposure to the external environment. Unique associations with xylem vessels suggested that fungi may actively transport water during drought. Colonization of the stomatal complex indicated a role in regulating gas exchange, photosynthesis and water loss by transpiration. We suggest that symbiotic fungi have a multifunctional role of enhancing drought tolerance of native desert plants. Improvement of native plants by conventional breeding or gene transfers is expensive and time-consuming. Manipulation of fungi rather than plants may provide a more efficient alternative for their improvement.}, keywords = {associations, composite, fungi, manipulation, native plants}, author = {J.R. Barrow and P. Osuna-Avila and I. Reyes-Vera} } @conference {50630, title = {Fungal genomes that influence basic physiological processes that enhance survival of black grama and fourwing saltbush in arid Southwestern rangelands}, booktitle = {13th Wildland Shrub Symposium, Shrubland Dynamics: Fire and Water}, year = {2004}, month = {August 10-12, 20}, address = {Lubbock, TX}, abstract = {Symbiotic fungi are generally known to enhance photosynthetic rates and drought tolerance in host plants, but mechanisms are currently unresolved. Shrubs and grasses of southwestern deserts are colonized by symbiotic fungi that cannot be removed by conventional sterilization methods. These fungi were extensively studied in native plants over a wide range of locations and environmental conditions. Fungi associated with native plants were also found to be intrinsically integrated with cells, tissues and regenerated plant cultures. Native grasses and shrubs were found to be composite plant-fungus organisms comprised of at least two fungal species. It is suggested that these inherent associations modify their hosts at the genetic, cell and physiological levels and positively enhance ecological fitness. Colonization of photosynthetic cells, encapsulation of chloroplasts and accumulation of lipids provided evidence for host modification and performance. Carbon management is suggested by the substantial quantities of high energy lipids that are stored and transported in sieve elements. Lipids converted to biofilms protected cells, tissues, roots and leaves from direct exposure to the external environment. Unique associations with xylem vessels suggested that fungi may actively transport water during drought. Colonization of the stomatal complex indicated a role in regulating gas exchange, photosynthesis and water loss by transpiration. We suggest that symbiotic fungi have a multifunctional role of enhancing drought tolerance of native desert plants. Improvement of native plants by conventional breeding or gene transfers is expensive and time-consuming. Manipulation of fungi rather than plants may provide a more efficient alternative for their improvement.}, keywords = {associations, composite, fungi, manipulation, native plants}, author = {J.R. Barrow and P. Osuna-Avila and I. Reyes-Vera} } @conference {50666, title = {Field application of the portable soil penetrometer and the soil erosion bridge}, booktitle = {57th Annual Meeting, Society for Range Management}, year = {2004}, month = {January 25, 2004}, pages = {141}, address = {Salt Lake City, UT}, abstract = {Two portable soil monitoring tools were developed to increase efficiency and repeatability of soildensity and soil erosion measurements. The soil penetrometer is well-suited for measuring soil densityin the highly compacted range soils of the Western United States. Soil density is measured by thenumber of strokes needed to push the penetrometer a certain distance in the soil. Constant weight andfalling height insure the repeatability of the method. The soil erosion bridge measures the depth of soileroded in a certain time period by comparing the position of medal rods on two digital images. Thedigital images are taken with a camera mounted onto the soil erosion bridge to ensure an exact position.Each of these commercially available devices has been refined to be carried and used by one person.This paper details the field application, data collection, and suggested protocol of the penetrometer andthe soil erosion bridge.}, author = {Jeffrey E. Herrick and J. Alexander and Kluck, J.} } @conference {50676, title = {Fire in Chihuahuan Desert grassland: effects on vegetation, small mammal populations, and biopedoturbation}, booktitle = {Sixth Symposium on the Natural Resources of the Chihuahuan Desert Region}, year = {2004}, month = {October 15, 2004}, pages = {30}, address = {Alpine, TX}, abstract = {We studied the effect of a prescribed burn in a black-grama-(Bouteloua eriopoda)-dominated desert grassland on vegetation, small mammals and biopedoturbation (soil disturbance by animals). The burn was conducted during the hot-dry season just prior to monsoon rains. One month post-burn, there were significant decreases in canopy cover of the grasses (Bouteloua eriopoda, Sporobolusflexuosus, and Aristida purpurea). One year post-burn, percent cover of B. eriopoda remained significantly lower than in unburned areas. There were no differences in cover of all other grass species in burned and unburned plots 1 year after the burn. Fire killed 100\% of the snakeweed shrubs (Gutierrezia sarothrae), 77\% of the Torrey ephedra (Ephedra torreyana), and 36\% of the soap tree yucca (Yucca elata). One year post-burn, the surviving Y. elata were significantly smaller than the soap tree yucca in the unburned sites. The fire resulted in top kill of all P. glandulosa in the burn areas but all of the mesquite resprouted from root crowns within 1 month after the burn. Fire had no effect on the abundance and diversity of small mammals. Area and volume of soil disturbed by animals (ant nest soil mounds, burrowing spider tunnels and ejected soil, and excavations by small mammals) were not significantly different in burned areas and unburned areas. The area and volume of soil in termite galleries and sheeting were significantly larger in the unburned grassland than in the burned areas.}, keywords = {biopedoturbation, Chihuahuan Desert, effects, fire, grassland, small mammal populations, vegetation}, author = {Aaron Killgore and E. Jackson and Walter G. Whitford} } @conference {50711, title = {Factors influencing the spatial variability of runoff at differing scales in the Jornada Basin}, booktitle = {Sixth Symposium on the Natural Resources of the Chihuahuan Desert Region}, year = {2004}, month = {October 15, 2004}, pages = {39}, address = {Alpine, TX}, abstract = {
Factors that cause high spatial variability of water in arid regions include precipitation, soil, physiographic, and vegetation characteristics. The inherent heterogeneity of arid lands causes areas of runoff and run-on at the individual plant scale as well as in large area patterns of banded vegetation and beaded drainage networks where run-on and infiltration spur vegetation growth. To rehabilitate degraded rangeland, it is wise to mimic nature by diverting water to target areas to create islands of hydrologically enhanced productivity or by installing structures, such as water ponding dikes, to promote a landscape change to resemble natural vegetation patterns
Note: This paper is an executive summary of the full length manuscript: Rango, A., S.L.
Tartowski, A. Laliberte, J. Wainwright, and A. Parsons. 2006. Islands of hydrologically enhanced
biotic productivity in natural and manged arid ecosystems. Journal of Arid Environments 65(2):235-252.
}, keywords = {arid climates, hydrologically enhanced productivity, Jornada Basin, physiographic, precipitation, runoff, soil, spatial variability}, author = {A. Rango and S. Tartowski and Andrea S. Laliberte and John Wainwright and A.J. Parsons} } @conference {50737, title = {Fluorometry as a tool for real-time botanical analysis}, booktitle = {VIIth International Rangeland Congress}, volume = {20}, year = {2003}, note = {Published in special section of Journal of Range and Forage Science--additional abstracts--from VIIth International Rangeland Congress, Africa}, month = {July 26, 2003}, pages = {132}, abstract = {Determining the botanical composition of forage and free-ranging animal diets is essential for accurate rangeland management and optimum economic returns. Multidimensional fluorometry offers a unique, real-time optical approach for accurately determining the composition of plant materials based on their chemical properties. By focusing on electronic transitions between 190 and 800 nm, specific chemical structures within dietary extrusa and fecal matter can be determined using trainable intelligent algorithms. During November 1991 we began investigating fluorometry as a tool to evaluate both pre- and post-digested plant materials. In the ensuing 12 years, light sources such as lasers and xenon arc lamps have been successfully used to excite fluorescence from plant and fecal extracts in both polar and nonpolar solvents. Unique spectral signatures in the blue, green and red regions of the visible spectrum were obtained. Prior research has concentrated on the acquisition and post-processing of excitation/emission matrices obtained from individual plant species as well as postdigested plant materials. Similarities have been shown among different plants within the same species of grass, forb and shrub as well as differences among grasses, forbs and shrubs. Statistical differences have also been found among simple diets containing varying amounts of one of the components. Previous research suggests fluorometry can become a promising method to differentiate between both pre- and postdigested plant materials. Current research using intelligent algorithms such as neural net processing to characterize three-dimensional spectral signatures among plants, including some poisonous to livestock, will be discussed.}, author = {D.M. Anderson and E. Parker and M. Ralphs and Gray, P. and G.D. Rayson and Richard E. Estell and Daniel, D. and E.L. Fredrickson and Kris Havstad and Wagner, J.} } @conference {50747, title = {A field guide to land: User-friendly interpretations of rangeland communities}, booktitle = {Second National Conference on Grazing Lands}, year = {2003}, month = {December 7-10, 2}, address = {Nashville, TN}, abstract = {The Ecological Site Descriptions (ESDs) of the USDA Natural Resources Conservation Service are a series of publically-available reports that provide interpretations of plant community composition and change that are based on climate, soil development, surface soil characteristics and fertility, and competition and disturbance to key plant species. A single ESD report is associated with several soil series occurring within climatic region. These reports can be used to help evaluate questions about land condition, such as: why is there so little black grama (Bouteloua eriopoda) on this site? The answer will be different depending on the location and history of the site: the climate may be too wet or the soil too clayey to support much black grama; black grama may have been abundant but was reduced due to historical degradation of the soil; or black grama has recently declined due to heavy grazing or drought, but can recover its former abundance. Choosing the right answer is critical for identifying real management options and avoiding needless controversy. ESDs are increasingly able to assist the analysis of plant and soil patterns but are difficult for the public to use. We provide an example and format for user-friendly versions of ESDs that features a range of decision support tools, including a series of keys and supplemental photographs, to guide interpretations of land condition in defined geographic areas.}, author = {Brandon T Bestelmeyer and Chavez, G. and Joel R. Brown and D. Trujillo} } @proceedings {50750, title = {Future directions in soil-vegetation descriptions: Systematizing dynamics}, year = {2003}, month = {June 16-20, 2003}, pages = {35-36}, address = {Plymouth, MA}, abstract = {State-and-transition models are being used to describe the coupled plant-soil dynamics in ecological site descriptions. Major challenges in producing these models include 1) distinguishing transient dynamics from changes persistent (and significant) enough to qualify as {\textquoteright}transitions{\textquoteright} as recently defined; 2) distinguishing true, self-reinforcing transitions from {\textquoteright}pseudo-transitions{\textquoteright} caused by persistent perturbation of a system due to continuous heavy grazing, for example, and that will return to the original state once the perturbation ceases; and 3) isolating present-day spatial heterogeneity within ecological sites that is attributable to transient or threshold dynamics from static patterns caused by differences among the soils grouped within ecological sites. If we are to foster a science-based understanding of rangeland ecosystems using ESDs, we must carefully consider how we treat these phenomena in models. We briefly review these challenges.}, author = {Brandon T Bestelmeyer and Joel R. Brown} } @article {50764, title = {Functional diversity revealed by removal experiments}, journal = {Trends in Ecology \& Evolution}, volume = {18}, year = {2003}, note = {//NMSU//LTER IV//}, month = {2003}, pages = {140-146}, abstract = {

The dominant protocol to study the effects of plant diversity on ecosystem functioning has involved synthetically assembled communities, in which the experimental design determines species composition. By contrast, the composition of naturally assembled communities is determined by environmental filters, species recruitment and dispersal, and other assembly processes. Consequently, natural communities and ecosystems can differ from synthetic systems in their reaction to changes in diversity. Removal experiments, in which the diversity of naturally assembled communities is manipulated by removing various components, complement synthetic-assemblage experiments in exploring the relationship between diversity and ecosystem functioning. Results of recent removal experiments suggest that they are more useful for understanding the ecosystem effects of local, nonrandom extinctions, changes in the natural abundance of species, and complex interspecific interactions. This makes removal experiments a promising avenue for progress in ecological theory and an important source of information for those involved in making land-use and conservation decisions.

}, keywords = {article, biodiversity, removal experiments, ecosystem function, biodiversity, journal}, doi = {10.1016/S0169-5347(03)00007-7}, url = {files/bibliography/JRN00385.pdf}, author = {Diaz, S. and A.J. Symstad and F.S. Chapin III and Wardle, D. A. and L. Huenneke} } @proceedings {50781, title = {Future directions: Using ESD{\textquoteright}s for assessment, monitoring and decision making}, year = {2003}, month = {June 16-20, 2003}, pages = {39-40}, address = {Plymouth, MA}, abstract = {Seven conclusions relevant to assessing and monitoring soil change can be drawn from developing these two protocols: (1) Emphasize properties important for ecosystem function and sensitive to a wide variety of uses, rather than those most sensitive to a particular land use. Individual land uses may no longer exist 100 or even 20 years from now and new ones will be developed. (2) Emphasize qualitative indicators for assessment and qualitative indicators for monitoring. (3) Include both current status and early warning indicators that reflect a change in the capacity of the system to resist (resistance) and recover from (resilience) degradation. (4) Use the cover, composition, condition and spatial distribution of vegetation to generate more cost-effective indicators that are potentially correlated with remote sensing indicators. (5) Generate reference data for a group of soils (ecological site) with a similar potential to conserve soil, capture and release water, and support plant communities that are resistant and resilient to degradation. (6) Use the threshold concept to help focus limited resources on those areas with the highest probability of relatively irreversible change. (7) Apply the following criteria to measurement and indicator selection: (a) clearly related to the properties and processes they are intended to reflect, (b) easy to measure repeatedly, ideally in the field, (c) minimal time is needed to complete the number of measurements required to detect a functionally significant difference at a specified level of statistical precision. Research and applied trials are clearly needed to address all three criteria. Additionally, because ecological site potential is defined as a function of climate and (relatively) static soil properties, we need to develop a better understanding of (1) the effects of spatial variability in relatively static soil properties on relatively dynamic soil properties, and (2) the effects of interactions between different soil properties (static/dynamic) and climate on ecological processes. This requires reference data for both relatively static and dynamic soil properties.}, author = {Jeffrey E. Herrick and A.J. Tugel} } @proceedings {50833, title = {Future directions in soil data applications: Assessment and monitoring}, year = {2003}, month = {June 16-20, 2003}, pages = {34-36}, address = {Plymouth, MA}, abstract = {Evaluations made through assessment and monitoring provide information about the functional status of the soil-plant system. Soil Survey can support assessment and monitoring activities of land managers by providing data to serve as standards or reference values using an objective-based approach for selection. The properties/indicators chosen should reflect the processes and functions to be assessed or monitored and the scale (e.g., management unit, ranch, watershed, eco-region, national) at which the information is needed. Good indicators are strongly related to the function and scale of interest, sensitive to change, compatible with time and resource availability and technical expertise, and relatively easy to observe or measure in a reliable manner.}, author = {A.J. Tugel and Jeffrey E. Herrick} } @article {50836, title = {The functional significance of cemented nest caps of the harvester ant, Pogonomyrmex maricopa}, journal = {Journal of Arid Environments}, volume = {53}, year = {2003}, note = {//USDA//LTER IV//}, month = {2003}, pages = {281-284}, abstract = {

Harvester ants, Pogonomyrmex maricopa, construct cemented caps on the sand mound nests in a fine sand dune area. The caps are approximately 60\% calcium carbonate that is transported from the underlying calcium carbonate layers. The caps protect the nest structure from being eroded away during high-wind periods. Partial erosion of the cemented caps adds calcium carbonate to the sand dune soils.

}, keywords = {ant nest, soil effects, ant, calcium carbonate, ant, harvester ant, ant, Pogonomyrmex, article, articles, calcium carbonate, ants, journal, journals, wind erosion, ants}, doi = {10.1006/jare.2002.1039}, url = {files/bibliography/JRN00399.pdf}, author = {Walter G. Whitford} } @article {50855, title = {Fire effects on resprouting of shrubs in headwaters of southeastern longleaf pine savannas}, journal = {Ecology}, volume = {83}, number = {3}, year = {2002}, month = {July 1, 2002}, pages = {755-767}, abstract = {

Woody plants in fire-frequented ecosystems commonly resprout from underground organs after fires. Responses to variation in characteristics of fire regimes may be a function of plant physiological status or fire intensity. Although these hypotheses have been explored for trees in southeastern longleaf pine (Pinus palustris) savannas, responses of other life forms and stages have not been studied. We examined effects of fire season and frequency, geography, habitat, and underground organ morphology on resprouting of shrubs. In 1994, we located replicated sites, each containing two habitats, upslope savannas and downslope seepages, in Louisiana and Florida. Each site, which contained quadrats located along transects within a 30 {\texttimes} 60 m plot, was burned either during the dormant or growing season and then reburned similarly two years later. Maximum fire temperatures were measured, and densities of shrub stems were censused in quadrats before and after fires. Shrubs collectively resprouted more following dormant than growing-season fires, regardless of habitat or geographic region. After repeated dormant-season fires, collective densities in seepages of both regions and densities of root-crown-bearing shrubs in Florida seepages were greater than those initially and after repeated growing-season fires. Shrub responses were generally unrelated to fire temperatures, supporting the hypothesis that resprouting of shrubs may be more dependent on their physiological status at the time of fires. There was, nonetheless, an inverse relationship between collective and root-crown-bearing shrub densities following repeated fires and maximum fire temperatures in Florida seepages. Anthropogenic dormant-season fires over many decades may have resulted in increases in shrub densities in longleaf pine savannas, especially seepages. Repeated growing-season fires, however, neither increased nor reduced densities of established shrubs. Long-term shifts in characteristics of fire regimes, even in fire-frequented habitats, may produce effects that are not reversible in the short term (\<10 yr) by simply reintroducing prescribed fires that resemble those that occurred naturally during the growing season.

}, keywords = {bogs; downslope seepages; fire frequency; fire season; fire temperature; Florida; Louisiana; rhizomes; root crowns; shrubs; upslope savannas}, doi = {10.1890/0012-9658(2002)083[0755:FEOROS]2.0.CO;2}, url = {/files/bibliography/02-104.pdf}, author = {Drewa, P.B. and Platt, W.J. and Moser, E.B.} } @conference {50862, title = {Fire as a management tool to facilitate expansion of reintroduced black-tailed prairie dog colonies in Chihuahuan Desert grasslands}, booktitle = {16th Annual Meeting, Society for Conservation Biology}, year = {2002}, month = {July 14, 2002}, pages = {3}, address = {Canterbury, UK}, abstract = {Within the last hundred years, public and private control programs and plague have reduced black-tailed prairie dog (Cynomys ludovicianus) population numbers by 98\%, causing localized extinctions. Black-tailed prairie dogs significantly alter grassland ecosystems and are considered a "keystone" species requiring active conservation efforts. We report on an experimental study evaluating fire vs. mowing for facilitating expansion of reintroduced colonies. We used three northern Chihuahuan Desert (Sporobolus/Scleropogon grassland association) colonies reestablished in 1998-99 ranging from 1.27 to 8 ha. Contiguous taller grasses limited expansion of these colonies. We established six 50x50m experimental plots adjacent to each colony randomly assigned to burn or mow treatments. All burrows in each colony were mapped immediately preceding treatment and 4-months after treatment. Numbers of newly established burrows in each plot were used as a measure of habitat preference. Results indicate no significant differences in the number of new burrows on burn (mean = 13, SD = 8) vs. mow (mean = 13, SD = 5) plots. In conclusion, fire can be used in lieu of mowing as a tool. Persistence of these treatments will depend on prairie dog population dynamics and impact of treatments on the foraging dynamics of associated large ungulates.}, author = {P. L. Ford and E.L. Fredrickson and C.A. Anderson and J. Truett} } @article {50873, title = {Forest carbon balance under elevated CO2}, journal = {Oecologia}, volume = {131}, year = {2002}, note = {//??//LTER IV//}, month = {2002}, pages = {250-260}, abstract = {

Free-air CO2 enrichment (FACE) technology was used to expose a loblolly pine (Pinus taeda L.) forest to elevated atmospheric CO2 (ambient + 200\ {\textmu}l l{\textendash}1). After 4\ years, basal area of pine trees was 9.2\% larger in elevated than in ambient CO2 plots. During the first 3\ years the growth rate of pine was stimulated by ~26\%. In the fourth year this stimulation declined to 23\%. The average net ecosystem production (NEP) in the ambient plots was 428\ gC\ m{\textendash}2\ year{\textendash}1, indicating that the forest was a net sink for atmospheric CO2. Elevated atmospheric CO2 stimulated NEP by 41\%. This increase was primarily an increase in plant biomass increment (57\%), and secondarily increased accumulation of carbon in the forest floor (35\%) and fine root increment (8\%). Net primary production (NPP) was stimulated by 27\%, driven primarily by increases in the growth rate of the pines. Total heterotrophic respiration (R h) increased by 165\%, but total autotrophic respiration (R a) was unaffected. Gross primary production was increased by 18\%. The largest uncertainties in the carbon budget remain in separating belowground heterotrophic (soil microbes) and autotrophic (root) respiration. If applied to temperate forests globally, the increase in NEP that we measured would fix less than 10\% of the anthropogenic CO2 projected to be released into the atmosphere in the year 2050. This may represent an upper limit because rising global temperatures, land disturbance, and heterotrophic decomposition of woody tissues will ultimately cause an increased flux of carbon back to the atmosphere.

}, keywords = {article, articles, carbon dioxide, carbon sequestration, carbon-balance, Free-air CO2 enrichment, Global carbon cycle, journal, journals, Pinus taeda}, doi = {10.1007/s00442-002-0884-x }, url = {files/bibliography/JRN00356.pdf}, author = {Hamilton, J. G. and DeLucia, J. E. and George, K. and Naidu, S. L. and W. H. Schlesinger} } @conference {50947, title = {Flerds affect free-ranging animal distribution during foraging}, booktitle = {55th Annual Meeting, Society for Range Management}, year = {2002}, month = {February 13, 200}, pages = {No. 83}, abstract = {The uniform distribution of free-ranging animals is the second most important management goal to be attained once a proper stocking rate has been established. Various management tools have been used to improve forage utilization. However, nonuniform landscape utilization still characterizes the foraging pattern of many animals, especially sheep and goats. Preliminary data suggests if sheep, goats, and cattle remain together as a flerd during foraging, grazing pressure is spread more uniformly over the landscape compared to the foraging pattern of flocks.}, keywords = {distribution, flerds, foraging, free-ranging animals}, author = {Sun, P. and L. W. Murray and D.M. Anderson and V.B. Nakamatsu and E.L. Fredrickson and Kris Havstad} } @conference {50962, title = {Fluorometry as a tool for determining botanical composition}, booktitle = {54th Annual Meeting of Society for Range Management}, year = {2001}, month = {February 2, 2001}, pages = {Abstract No. 10}, address = {Kailua-Kona, HI}, abstract = {Multidimensional fluorometry measurements offer a unique chemical approach for determining botanical composition of animal diets. By focusing on electronic transitions between 190 and 800 nm specific chemical structures within materials such as fecal matter and dietary extrusa can be determined in real time using simple "trainable" algorithms. In November 1991, we began investigating fluorometry as a tool to evaluate pre- and post-digested diets of free-ranging animals. During the ensuing nine years, a laser as well as some xenon arc lamps have been used to excite fluorescence from plant and fecal extracts in polar as well as non-polar solvents. Unique spectral signatures in the blue, green and red regions of the visible spectrum were obtained. Research to date has concentrated on the acquisition and post-processing of excitation/emission matrices. Results suggest the technique has the ability to discriminate differences among pre-digested grasses, forbs and shrubs as well as reveal similarities among different plants within a species. In addition, simple diets containing varying amounts of one of the components can be statistically separated using distinct peaks as well as the entire fluorescence data set. Current and future research using fluorometry will be discussed.}, keywords = {animal diets, botanical composition, chemical approach, fluorometry, measurements}, author = {D.M. Anderson and G.D. Rayson and Richard E. Estell and E.L. Fredrickson and Kris Havstad and Tisone, G. and Daniel, D. and L. W. Murray} } @proceedings {50982, title = {Fire, grazing and honey mesquite invasion in black grama-dominated grasslands of the Chihuahuan Desert: a synthesis}, year = {2001}, month = {November 28-Dece}, pages = {31-39}, address = {Tallahassee, FL}, abstract = {Prior to European settlement, the Chihuahuan Desert was partly comprised of grasslands dominated by the perennial grass, black grama (Bouteloua eriopoda), as well as by other species of herbaceous vegetation. Honey mesquite (Prosopis glandulosa) was mostly abundant in adjacent lower lying areas of water runoff and intermittent streambeds. Since the late 19th century, however, cattle have been directly responsible for increased abundances and expanded distributions of honey mesquite through consumption and dissemination of seed. Additionally, a period of overgrazing and interactive effects with other factors, such as drought and small mammal herbivory, resulted in reduced abundances of black grama. As a result of decreased fuel abundance, lightning-initiated fires that likely occurred just prior and throughout the growing season have decreased in size, intensity, and frequency. Despite reductions in herbaceous fuels following gEuropean settlement, we hypothesize that fire remains effective in topkilling shrubs of honey mesquite and, in so doing, may directly interfere with its development toward reproductive maturity and its ability to set seed. Based on information from the literature and results from our research, complete kill of honey mesquite is rare. However, fire is effective in topkilling and returning shrubs to an immature life history stage. Fire remains an effective deterrent in slowing honey mesquite invasion. However, the recurrence of fire is highly contingent on the degree and rate of black grama recovery that may be determined by the timing and amount of precipitation immediately following fires, as well as the degree of livestock grazing.}, keywords = {Chihuahuan Desert, fire, grazing, honey mesquite, invasion}, url = {/files/bibliography/01-020.pdf}, author = {Drewa, P.B. and Debra C. Peters and Kris Havstad} } @proceedings {50984, title = {Fire, grazing, and shrub invasion in the Chihuahuan Desert}, year = {2001}, note = {//?//LTER IV//}, month = {2001}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, control, fire-control, grazing, proceeding, proceedings, shrub invasion}, author = {Drewa, P.B. and Debra C. Peters and Kris Havstad}, editor = {Wilson, T. P. and K. E. M. Galley} } @article {51006, title = {Field soil aggregate stability kit for soil quality and rangeland health evaluations}, journal = {CATENA}, volume = {44}, number = {1}, year = {2001}, note = {Full Article from CATENA posted on this website with permission from Elsevier Science (http://www.elsevier.com/locate/catena). Single copies of the article can be downloaded and printed for the reader{\textquoteright}s personal research and study.}, month = {May 18, 2001}, pages = {27-35}, abstract = {

Soil aggregate stability is widely recognized as a key indicator of soil quality and rangeland health. However, few standard methods exist for quantifying soil stability in the field. A stability kit is described which can be inexpensively and easily assembled with minimal tools. It permits up to 18 samples to be evaluated in under 10 minutes and eliminates the need for transportation, minimizing damage to soil structure. The kit consists of two 21 x 10.5 x 3.5 cm plastic boxes divided into eighteen 3.5 x 3.5 cm sections, eighteen 2.5 cm diameter sieves with 1.5 mm distance openings and a small spatula used for soil sampling. Soil samples are rated on a scale from 1 to 6 based on a combination of ocular observations of slaking during the first 5 minutes following immersion in distilled water, and the percent remaining on a 1.5 mm sieve after 5 dipping cycles at the end of the 5 minute period. A laboratory comparison yielded a highly significant linear correlation between the stability class and percent aggregate stability based on oven dry weight remaining after treatment using a mechanical sieve. The relationship was not statistically different for a sandy clay loam and a loamy sand. We have applied the method in a wide variety of agricultural and natural ecosystems throughout western North America, including northern Mexico, and have found that it is highly sensitive to differences in management and plant community composition. Although the field kit cannot replace careful laboratory-based measurements of soil aggregate stability, it can clearly provide valuable information when these more intensive procedures are not possible.

}, doi = {10.1016/S0341-8162(00)00173-9}, url = {/files/bibliography/01-032.pdf}, author = {Jeffrey E. Herrick and Walter G. Whitford and A.G. de Soyza and Justin Van Zee and Kris Havstad and C. Seybold and Walton, M.} } @article {51192, title = {Field and computer simulation experiments on the formation of desert pavement}, journal = {Earth Surface Processes and Landforms}, volume = {24}, year = {1999}, note = {//Walnut Gulch//NONE//PDF on file}, month = {1999}, pages = {1025-1037}, abstract = {A series of rainfall simulation experiments was carried out at the Walnut Gulch Experimental Watershed, Tombstone, Arizona, to observe the speed at which desert pavement surfaces could be re-established following disturbance. The results of these experiments, which consisted of repeated, 5 min rainfall events, demonstrate that pavements can reform within 10 events, which is compatible with observations of the recovery of surfaces under natural rainfall on an annual cycle. A model for the development of pavements by raindrop erosion processes had previously shown the importance of these processes. The rainfall simulation experiments were used to test the general applicability of this model. The model was able to reproduce the general characteristics of the regenerated surfaces and the timing of their development. However, details of the particle size fractions produced were less well simulated by the model. Testing of the sensitivity of the model to the sediment transport parameters suggests that this problem is not related to the soil characteristics, but is more likely to be an indication of a poor understanding of all the feedbacks operating in the raindrop erosion processes. Copyright {\textcopyright} John Wiley \& Sons, Ltd.}, keywords = {article, articles, desert pavement, erosion, raindrop, journal, journals, model, simulation, raindrop erosion, rainfall simulation, desert pavement, rainfall simulation,erosion, simulation model}, author = {John Wainwright and A.J. Parsons and Athol D. Abrahams} } @article {51260, title = {Fungal root endophytes in fourwing saltbush, Atriplex canescens, on arid rangelands of southwestern USA}, journal = {Arid Soil Research and Rehabilitation}, volume = {11}, year = {1997}, month = {1997}, pages = {177-185}, abstract = {

This research was conducted to determine the nature and incidence of fungal root endophytes on fourwing saltbush, Atriplex canescens (Pursh) Nutt. Root cortex cells of fourwing saltbush in arid rangelands of the southwestern United States were analyzed and found to be regularly colonized with three types of endophytic fungi: septate, vesicular-arbuscular mycorrhizae (VAM), and Chytridiomycetes. Septate fungi were 2.7 times more prevalent than VAM and formed intimate non-pathogenic associations characterized by inter- and intracellular hyphae, coils, microsclerotia, and occasional labyrinthine or "Hartig net" structures similar to those affiliated with ectendomy-corrhizae. External hyphae formed intimate associations with soil and sand panicles. Typically, VAM were characterized by hyphae, vesicles, and (at times) coils. VAM were 2.2 times more prevalent than chytrids. Chytrids were rather common and were expressed as resting and active sporangia found within root cortex cells. The widespread occurrence of these non-destructive fungal associations with plants implies that they have an important role in plant survival in arid environments.

}, keywords = {arid ecology, chytrids, land restoration, mutualism, mycorrhizae, range-land, saprophytic fungi, symbiosis, VAM}, doi = {10.1080/15324989709381470}, url = {/files/bibliography/468.pdf}, author = {J.R. Barrow and Kris Havstad and McCaslin, B D.} } @article {51293, title = {Factors controlling threshold friction velocity in semiarid and arid areas of the United States}, journal = {Journal of Geophysical Research}, volume = {102}, year = {1997}, note = {//??//LTER-III//}, month = {1997}, pages = {23277-23287}, abstract = {

A physical model was developed to explain threshold friction velocities u*t for particles of the size 60{\textendash}120 {\textmu}m lying on a rough surface in loose soils for semiarid and arid parts of the United States. The model corrected for the effect of momentum absorption by the nonerodible roughness. For loose or disturbed soils the most important parameter that controls u*t is the aerodynamic roughness height z0. For physical crusts damaged by wind the size of erodible crust pieces is important along with the roughness. The presence of cyanobacteriallichen soil crusts roughens the surface, and the biological fibrous growth aggregates soil particles. Only undisturbed sandy soils and disturbed soils of all types would be expected to be erodible in normal wind storms. Therefore disturbance of soils by both cattle and humans is very important in predicting wind erosion as confirmed by our measurements.

}, keywords = {eolian, physical model, soil crusts, soil disturbance, threshold friction velocity, wind erosion}, doi = {10.1029/97JD01303}, url = {files/bibliography/JRN00237.pdf}, author = {B{\'e}atrice Marticorena and Gilles Bergametti and D. E. Gillette and Jayne Belnap} } @article {51296, title = {Fractal modeling of airborne laser altimetry data}, journal = {Remote Sensing of Environment}, volume = {61}, year = {1997}, note = {//USDA//LTER III//}, month = {1997}, pages = {150-161}, abstract = {

Airborne laser altimetry is a remote sensing technique that can provide high resolution data on the roughness of the landscape both for estimating water balance components and for distinguishing between landscapes. Models of the scale-dependent roughness are needed to find scales most appropriate for these purposes. Our objectives were to apply fractal scaling to high-resolution profiling laser altimetry data and to determine fractal parameters fro differentiating land cover. Data were collected at the USDA-ARS Jornada Experimental Range in New Mexico over grass-dominated and shrub-dominated sites along four transects at each site. Scale-dependent root-mean-square (RMS) roughness and data power spectrums were computed from 100,000 data points (~2 km) from each transect. A linearity measure and piecewise linear approximation were applied to find intervals of the fractal scaling. The RMS roughness data had two intervals of self-affine fractal scaling on grass transects and four such intervals on shrub transects. Reduction in the number of data points did not lead to a decrease in roughness but caused a smoothing dependency of fractal dimension on scale. Ten- and hundred-meter scales were appropriate for distinguishing between grass and shrub transects on the basis of fractal dimensions. Published by Elsevier Science Inc.

}, keywords = {article, articles, JORNEX, remote sensing, journal, journals, landscape, surface roughness, laser altimetry, surface roughness, remote sensing, airborne laser altimetry, remote sensing, JORNEX, remote sensing, surface roughness, technique, airborne laser altimetry, technique, remote sensing, water balance, remote sensing}, doi = {10.1016/S0034-4257(96)00249-0}, url = {files/bibliography/JRN00238.pdf}, author = {Y. Pachepsky and Jerry Ritchie and Gimenex, Daniel} } @conference {51344, title = {Farmer needs and criteria for soil quality assessment tools}, booktitle = {American Society of Agronomy Meetings}, year = {1996}, month = {November 3-7, 19}, pages = {Abstract 50}, address = {Indianapolis, IN}, keywords = {assessment tools, soil quality}, author = {Jeffrey E. Herrick and Ericksen, P. and G. Johnson and Kohlmeier, L. and Morrone, V.L. and Scrimger, J.} } @article {51366, title = {Fire studies in Mallee (Eucaluptus spp.) communities of western New South Wales: Spatial and temporal fluxes in soil chemistry and soil biology following prescribed fire}, journal = {Pacific Conservation Biology}, volume = {2}, year = {1996}, month = {1996}, pages = {398-413}, abstract = {

The effects of prescribed fires on nutrient pools, soil-organisms, and vegetation patch dynamics were studied in three semi-arid mallee shrublands in western New South Wales. Repeated sampling of surface soil strata (0-2 and 2-4 cm) was undertaken at strategic times (immediately before and after the fire, after opening autumn rain, mid-season in the winter, and at the end of the spring) in five microsites (inner, middle and outer mallee litter zones, bare soil, and Triodia hummock). These samples were later analysed for pH, electrical conductivity, organic carbon and available nitrogen. The effect of fire on soil micro-organisms in these microsites was also examined by measuring nitrogenase activity and enumerating soil Acari. Carbon and nitrogen levels were consistently higher in the inner mallee microsites whereas bare soil sites provided the lowest values. Significant microsite times soil depth interactions were recorded in two shrubland sites while highly significant (P lt 0.001) depth times sampling time inteactions were recorded in three sites. The most sensitive soil parameter with respect to microsite was electrical conductivity, particularly in the surface 0-2 cm stratum. Highest values were again recorded from the inner mallee microsites and the lowest from bare soil sites. Nitrogenase activity was highest in soil samples associated with mallee litter and, where litter was removed by fire, activity decreased markedly except in the bare soil samples where activity was higher in the burnt samples. Soil microarthropod populations also declined notably following fire. Mites from the Prostigmata greatly outnumbered those from other suborders, a total of 12 familes (15 genera) being enumerated in control sites compared with three families (three genera) only of Cryptostigmata. Nonetheless the most abundant mites were cryptostigmatids (Aphelacarus spp.) found in unburnt hummocks beneath Triodia plants. The ecological and management implications of these spatial and temporal fluxes in soil chemistry and soil biology are discussed in relation to their effects on landscape processes, particularly water and nutrient redistribution.

}, keywords = {communities, Eucaluptus spp, Fire studies, New South Wales, prescribed fire, soil biology, soil chemistry, spatial, temporal fluxes}, doi = {10.1071/PC960398}, url = {files/bibliography/96-PacConsvtnBiology-Whitford.pdf}, author = {J. Noble and Tongway, D.J. and Roper, M.M. and Walter G. Whitford} } @article {51387, title = {Field simulation of wet and dry years in the Chihuahuan Desert: Soil moisture, N mineralization and ion exchange resin bags}, journal = {Biology and Fertility of Soils}, volume = {20}, year = {1995}, month = {1995}, pages = {137-146}, abstract = {

Irrigation and rain-out shelters were used to simulate precipitation patterns of wet and dry years in the northern Chihuahuan Desert. Irrigation provided approximately double the long-term average monthly precipitation. Rain was excluded during the wet season, July-October, to simulate a dry year. N net mineralization in laboratory incubations was undectable at calculated water potentials less than -1 MPa. With increasing moisture, mineralization gradually rose to the highest observed rates near field capacity. There was no mineralization maximum at moisture contents below field capacity. Irrigation significantly increased the water potential and rainfall exclusion reduced water potentials to less than -8 MPa. The general absence of important irrigation effects may have resulted from the high natural precipitation during the experiment or because irrigation inputs were insufficient to increase microbial activity during very dry periods. Precipitation exclusion reduced ion capture during the warm-wet season. After allowing precipitation inputs to resume, NH4-N capture was increased in the cool-dry seasons of both 1987-1988 and 1988-1989. NH4-N capture more than doubled that predicted from the overall covariance of moisture input and ion capture, suggesting increased availability of N. An unusually hot, dry period in May and June 1989 was followed by a three-to fourfold increase in the warm-wet season N03+N02-N capture compared to 1988. These data suggest that short droughts of about 3 months in length (both simulated and natural) increased N availability relative to moisture availability.

}, keywords = {Analysis of covariance, Chihuahan Desert, Field capacity, Larrea tridentata, Mineralization rate, Precipitation exclusion, simulated rainfall, Soil drying effects}, doi = { 10.1007/BF00336593}, url = {/files/bibliography/441.pdf}, author = {F. M. Fisher and Walter G. Whitford} } @article {51389, title = {Factors determining soil microbial biomass and nutrient immobilization in desert soils}, journal = {Biogeochemistry}, volume = {28}, year = {1995}, note = {//USDA//LTER III//}, month = {1995}, pages = {55-68}, abstract = {

We examined the 10-day response of soil microbial biomass-N to additions of carbon (dextrose) and nitrogen (NH4NO3) to water-amended soils in a factorial experiment in four plant communities of the Chihuahuan desert of New Mexico (U.S.A.). In each site, microbial biomass-N and soil carbohydrates increased and extractable soil N decreased in response to watering alone. Fertilization with N increased microbial biomass-N in grassland soils; whereas, fertilization with C increased microbial biomass-N and decreased extractable N and P in all communities dominated by shrubs, which have invaded large areas of grassland in the Chihuahuan desert during the last 100 years. Our results support the hypothesis that the control of soil microbial biomass shifts from N to C when the ratio of C to N decreases during desertification.

}, keywords = {article, articles, biogeochemistry,carbon, biogeochemistry,nitrogen, biogeochemistry,nutrient immobilization, carbon,soil, grassland,microbial biomass, journal, journals, nitrogen,soil, nutrient,soil, playa,microbial biomass, shrubland,microbial biomass, soil,microbial biomass, soil,nutrient immobilization}, url = {files/bibliography/JRN00189.pdf}, author = {Gallardo, Antonio and W. H. Schlesinger} } @article {51454, title = {Fruit abortion in Yucca elata and its implications for the mutualistic association with yucca moths}, journal = {Oikos}, volume = {69}, year = {1994}, note = {//NMSU//LTER II//}, month = {1994}, pages = {207-216}, abstract = {

The yucca moth Tegeticula yuccasella is the sole pollinator of Yucca elata, and relies on yucca fruits to complete its life cycle. A high percentage of pollinated flowers abort, killing the T. yuccasella eggs and larvae in them. We examined patterns of fruit production and abortion in Y. elata, and related these patterns to vegetative characteristics, moth abundance, and environmental conditions. We studied 38 inflorescences throughout their flowering period, during one season in southern New Mexico, USA. Each night we recorded the number of flowers opening, the number of fruit formed, the relative abundance of yucca moths, and climatic conditions. We monitored 11,786 flowers, resulting in 699 mature fruit. Large inforescences produced more, but proportionately fewer fruit than small inflorescences. Inflorescences flowering late in the season produced proportionately more fruit than inflorescences flowering early. Only 6.6\% (extremes 1.4-15.1\%) of flowers produced mature fruits. Hand-pollination of all flowers on inflorescences did not significantly increase the proportion of flowers that developed into mature fruit. Fruit production appeared to be resource-, not pollinator- limited. Ninety per cent of observed moth-pollinated flowers aborted (N=31), resulting in the death of moth eggs and larvae laid in the flowers. Neither yucca moth abundance or climatic conditions correlated with fruit production. Inflorescences usually developed mature fruit from flowers opening during a \"window\" of consecutive nights, lasting for five nights on average (36\% of the flowering period of an inflorescence). The timing of the window of fruit production was highly variable and unpredictable: mature fruits were produced from flowers opening at the beginning, in the middle, or at the end of the flowering period of an inflorescence. The results for Y. elata do not support existing hypotheses that attempt to explain patterns of selective fruit production. High rate of abortion of initiated fruit, and the apparently unpredictable pattern of fruit production by individual inflorescences, may stabilize the mutualistic interaction by preventing yucca moths from hyper-ovipositing flowers that have a high probability of developing into mature fruits. A risk-spreading strategy of oviposition is likely to be more successful for the moth than multiple ovipositions per flower.

}, keywords = {article, articles, insect, Tegeticula, insect, yucca moth, journal, journals, Tegeticula, Yucca pollination, yucca moth, SEE , Yucca, fruit abortion, Yucca, mutualism, Yucca, pollination, Yucca, yucca moth}, doi = {10.2307/3546140}, url = {files/bibliography/94-Oikos-Whitford.pdf}, author = {Craig D. James and Hoffman, M. Timm and David C. Lightfoot and Gregory S. Forbes and Walter G. Whitford} } @article {51457, title = {Factors affecting loss in mass of creosotebush leaf-litter on the soil surface in the northern Chihuahuan Desert}, journal = {The Southwestern Naturalist}, volume = {39}, number = {1}, year = {1994}, note = {//NMSU//LTER III//entered 04/14/2008; PDF available}, month = {1994}, pages = {78-82}, abstract = {

We examined the relative importance of biotic factors (microarthropods, termites, and fungi), and abiotic weathering on loss in mass of creosotebush leaf-litter on the soil surface in the northern Chihuahuan Desert. We treated litter with either an insecticide (chlordane), a fungicide (benomyl), a general biocide (HgCl2-CuSO4 solution or, as a control, distilled water. Our results suggest that microarthropods and fungi do not play significant roles in creosotebush litter decomposition in arid habitats. The rate of loss in mass from fungicide treated litter was not significantly different from control litter. Litter in fungicide treatment plots differed from that of the abiotic treatment plots in having higher rates of loss, suggesting that other components of the litter communities compensate for the lack of certain organismal groups. The rate of loss in litter treated with the general biocide during late summer was not significantly different from the rates for other litter, demonstrating that abiotic factors have an important effect. We suggest that these factors include intense sunlight and high UV-radiation and heat of the soil surface in summer. Actual evapotranspiration and decomposition rates of surface litter are uncorrelated in desert ecosystems. This may be due to abiotic fragmentation of the litter and the necessity of a threshold (amount or intensity) of rainfall which is necessary to fragment litter and wash it into the soil.

}, keywords = {article, decomposition, abiotic factors, decomposition, aboveground, decomposition, biotic factors, decomposition, Larrea litter, decomposition, leaf litter, decomposition, litter, nematodes, decomposition, litter, termites, decomposition, microarthropods, decomposition, organic matter turnover, decomposition, rates of, decomposition,fungal, journal}, doi = {10.2307/3672197 }, url = {files/bibliography/JRN00176.pdf}, author = {William P. MacKay and S. J. Loring and J. C. Zak and Solange Silva and F. M. Fisher and Walter G. Whitford} } @article {51461, title = {Free-ranging cattle water consumption in south-central New Mexico}, journal = {Applied Animal Behavior Science}, volume = {39}, year = {1994}, note = {Reprinted with permission from Elsevier, {\textcopyright} 1994. http://www.sciencedirect.com/science/journal/01681591}, month = {1994}, pages = {29-38}, abstract = {

Water-drinking behavior of 67 free-ranging protein supplemented and nonsupplemented beef cattle was examined between May 23 and 16 July 1986, in southcentral New Mexico. The lactating and nonlactating cows had a mean liveweight of 383 kg and were maintained as a single herd, and separated only during supplementation with an automated sorting and single animal electronic identification system. Mean daily water consumption was 57 1 day-1 ( 16 1 ( 100 kg liveweight)-1) at a rate of 20 1 min-1 under mean mid-range ambient air temperatures between 14 and 24{\textdegree}C. Water consumed by cows supplemented at 0.7 kg head-1 day-1 and 1.4 kg head-1 day-1 fed every 5.9 days and 3.5 days, respectively, was 14 1 (100 kg liveweight)-1 \ and 15 1 (100 kg liveweight)-1 (P=0.7238), respectively. In contrast, nonsupplemented cows consumed more (P<=0.0015) water (17 1 (100 kg liveweight)-1) than supplemented cows. Lactating cows consumed more water (P\<0.0001) than nonlactating cows ( 19 1 (100 kg liveweight)-1 and 12 1 (100 kg liveweight)-1, respectively). One drinking event every 24 h was sufficient to satisfy cows 94\% of the time. Neither supplement level nor lactation affected (P\>0.05) daily watering frequency. Water intake was negatively correlated to predrinking liveweight (r= -0.19; P\<0.01) and the current day{\textquoteright}s maximum ambient air temperature if greater than or equal to 30{\textdegree}C (r=-0.11; P\<0.02). Water intake was not correlated to temperatures <=30{\textdegree}C. Water consumption was positively correlated to relative humidities between 15 and 86\% (r=0.17; P\<0.01). Water consumption was not correlated (P\>0.05) with the mid-range or maximum ambient air temperatures of the current or previous day. Our findings indicate large feedings of protein reduced water consumption, probably as a consequence of lower forage intake. Lactation increased water requirements and liveweight was a poor predictor of water needs. Water consumption is affected by biotic and abiotic factors other than those we evaluated.

}, keywords = {cattle, Drinking behavior, feeding, grazing, nutrition}, doi = {10.1016/0168-1591(94)90013-2}, url = {/files/bibliography/432.pdf}, author = {R. R. Rouda and D.M. Anderson and Wallace, J.D. and L. W. Murray} } @conference {51469, title = {Facilitating mixed-species management of sheep with cattle through bonding}, booktitle = {Annual Meeting, Society for Range Management}, year = {1993}, month = {1993}, pages = {No. 96}, abstract = {If sheep are managed together with cattle under free-ranging conditions, the two species do not consistently stay together. However, by confining weaned lambs with cattle for 30 to 60 d, an affinity or bond develops that will endure over time. These bonded sheep will remain in close proximity to cattle under pasture conditions. Bonding research dating from 1985 is discussed with emphasis on how bonding has reduced coyote predation, eliminated additional time required to locate sheep under mixed-species stocking, acted as a nonwire fence to provide an alternative to conventional sheep-proof fencing and increased the spatial grazing pattern of free-ranging sheep without significantlymodifying sheep diets compared to nonbonded sheep. The cost to produce a bonded sheep using pen confinement in 1992 was approximately $0.55/hd/d.}, author = {D.M. Anderson and Kris Havstad and Shupe, W. Larry and R. Libeau} } @article {51521, title = {Feeding cull onions: The {\textquoteright}ins{\textquoteright} and {\textquoteright}outs{\textquoteright}}, journal = {Sheep Magazine}, year = {1992}, month = {October 1, 1992}, pages = {17,32}, abstract = {

The most costly aspect of any sheep operation is the cost associated with feed. Because of this, a resourceful operator is always looking for ways to cut feed costs as a means of increasing profits. One potential source of low cost, good quality, feed is cull onions.

}, url = {/files/bibliography/383.pdf}, author = {E.L. Fredrickson} } @article {51522, title = {Feeding cull onions to sheep}, journal = {Ranch Magazine}, year = {1992}, month = {October 1, 1992}, pages = {44}, abstract = {Several years ago during a visit to the Las Cruces city landfill, we saw a small mountain of cull onions with several pickups parked around it. People were climbing over the pile looking for the best onions to load in their pickups to either eat or sell. While watching the people sort through the onions we wondered if we could use onions as a livestock feed. Sometime later we searched various journals to learn what is currently known about feeding cull onions to livestock. To our surprise, there was very little information. Most all the articles available only described a condition termed "oxlion poisoning," a condition where sulfur compounds in onions cause red blood cells to loose their ability to carry oxygen and eventually the red blood cells die. Despite these reports in the literature, we knew of a few sheep producers who were feeding cull onions. It became obvious to us that research designed to determine the amount of onions that could safely be fed to sheep might be useful to sheep producers and onion growers alike. Onions are potentially an inexpensive feed. Also, cull onions reentering the market place negatively affect market demand for onions and onion prices. With aid from the New Mexico Dry Onion Commission, we completed two studies using sheep.}, keywords = {cull onions, inexpensive feed, livestock feed, oxlion poisoning, sheep}, url = {/files/bibliography/384.pdf}, author = {E.L. Fredrickson and Shupe, W. Larry} } @article {51529, title = {Functional dioecy in Echinocereus coccineus (Cactaceae): Breeeding system, sex ratios, and geographic range of floral dimorphism}, journal = {American Journal of Botany}, volume = {79}, number = {12}, year = {1992}, note = {//NMSU//LTER-II//}, month = {1992}, pages = {1382-1388}, abstract = {The breeding system of the hedgehog cactus, Echinocereus coccineus Engelm. (Cactaceae), was studied at two sites in the northern Chihuahuan Desert, New Mexico. Two distinct flower types, restricted to separate plants, were observed. One was hermaphroditic and the other male-sterile. Hand-pollinations and field observations showed them to be functionally male and functionally female, respectively. There were significant quantitative intersexual differences in floral morphology. the main pollinators of the populations studied are probably two species of halictid bee. Sex ratios based on the number of plants and flowers at the two sites did not differ significantly from 1:1. Significant differences in fruit set existed between functional female plants from the two sites. The floral dimorphism described here appears confined to eastern and northwestern populations, at the periphery of the range of E. coccineus. Floral dimorphism was not observed in three closely related species.}, keywords = {article, articles, Cactaceae, Echinocereus, Echinocereus, reproduction, journal, journals, reproduction, Cactaceae}, author = {Hoffman, M. Timm} } @article {51533, title = {Field versus pen bonding lambs to cattle}, journal = {Sheep Research Journal}, volume = {8}, number = {2}, year = {1992}, month = {1992}, pages = {69-72}, abstract = {

Complementary grazing of cattle and sheep promotes more uniform and efficient utilization of forages, because of differences in dietary preferences (Stoddard and Smith, 1943; Baker, 1985). Therefore, it is possible to co-graze 2 or 3 sheep for each cow on many ranches without reducing cow numbers. However, coyote predation and locating sheep in shrub infested pastures conducive to coyote predation are two challenges that confront mixed-species management systems (Etchepare, 1985; Merrill, 1985).

}, keywords = {behavior, bonding, mixed-species stocking, predator, sheep}, url = {/files/bibliography/391.pdf}, author = {Clarence V. Hulet and D.M. Anderson and Shupe, W. Larry and L. W. Murray} } @conference {51546, title = {Fungal interactions of key Chihuahuan Desert grasses}, booktitle = {Annual Meeting, Society for Range Management}, year = {1992}, month = {1992}, pages = {Abstract No. P039}, abstract = {Fungal symbionts are recognized as important in the ecology of desert plant communities.Mycorrhizal associations can influence plant establishment, growth, and reproduction. In the Chihuahuan Desert two of the dominant shrubs (Larrea tridentata and Prosopis glandulosa) are recognized as endomycorrhizal, an attribute which may contribute to the competitiveness of these species in this environment. We hypothesize that principle native perennial grasses may not effectively exploit mycorrhizal associations. Our initial study objective was to examine the nature and extent of mycorrhizal infections of six key native perennial grass species found in association with these shrubs. Bouteloua eriopoda, Aristida longiseta. Sporobolus flexuosus,Hilana mutica, Muhlenbergia porteri, and Scleropogon brevifolius specimens were collected biweekly from June through September, a schedule which bracketed the summer growing season. Staining techniques identified histochemical activities as related to mycorrhizal structures, including vesicles and arbuscules. Separation techniques isolated fungal spores for inoculation of a nonendemic host and subsequent species identification. Data will be presented on the temporal nature of mycorrhizal infection of these perennial grasses. It is assumed that differential fungal symbiont activities may partly explain vegetation dynamics and soil microflora requirements for subsequent restoration of perennial grasses.}, keywords = {Chihuahuan Desert, desert plant communities, ecology, fungal interactions, grasses, mycorrhizal associations, symbionts}, author = {Saar, L.J. and J.R. Barrow and Kris Havstad} } @article {51589, title = {Factors controlling denitrification in a Chihuahuan Desert ecosystem}, journal = {Soil Science Society of America Journal}, volume = {55}, number = {6}, year = {1991}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1991}, pages = {1694-1701}, abstract = {

A factorial experiment was conducted to determine the factors controlling denitrification in the northern Chihuahuan Desert. Specifically, we measured the response of denitrification to additions of water, C, N, and C + N.... When denitrification rates were averaged across vegetation zones and patch types (between or under vegetation), the following treatment effects were significantly different: water + NO3 + C \>\>\> water + NO3 = water \>\> water + C \> control. These results indicate that denitrification at this site is limited by the availability of water. (The study was conducted along the LTER-I Control Transect.)

}, keywords = {article, articles, denitrification, journal, journals, soil, denitrification, transect, denitrification}, doi = {10.2136/sssaj1991.03615995005500060032x }, url = {files/bibliography/JRN00136.pdf}, author = {Peterjohn, William T. and W. H. Schlesinger} } @proceedings {51602, title = {Forage intake and utilization by suckling range calves}, volume = {41}, year = {1990}, month = {1990}, pages = {268-271}, keywords = {forage intake, forage utilization, range calves, suckling}, author = {Ansotegui, R.P. and Wallace, J.D. and Kris Havstad and M.K. Petersen and Galyean, M.L.} } @article {51626, title = {Factors affecting annual plant assemblages on banner-tailed kangaroo rat mounds}, journal = {Journal of Arid Environments}, volume = {18}, year = {1990}, note = {//NMSU//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1990}, pages = {165-173}, abstract = {

We studied patterns of annual plants assemblages and soil properties of banner-tailed kangaroo rat (Dipodomys spectabilis) mounds. The spring annual flora on mounds was dominated by Descuraina pinnata and Eschscholtzia mexicana; intermound areas were dominated by Eriastrum diffusum. The peak above-ground standing biomass of spring annuals on mounds and intermounds respectively was 133{\textperiodcentered}3 {\textpm} 5{\textperiodcentered}9 g m-2 and 25{\textperiodcentered}6 {\textpm} 6{\textperiodcentered}3 g m-2. In summer, the mounds had a high density and biomass of Tidestromia lanuginosa. Intermound areas were dominated by Haplopappus gracilis and Eriogonum abertianum. The peak above-ground standing biomass of summer annuals on mounds and intermounds respectively, was 172{\textperiodcentered}7 {\textpm} 7{\textperiodcentered}3 g m-2 and 98{\textperiodcentered}4 {\textpm} 2{\textperiodcentered}3 g m-2. The above-ground standing biomass of annual plants on irrigated mounds in spring and summer was greater than on non-irrigated mounds. Bulk density was lower on mounds; nitrate and total nitrogen contents of the mound soils were higher than those of intermound soils. Available nitrate measured by absorption on ion exchange resins was consistently higher in mound soils than in intermound soils except for the period from March to April. Mound soils dried faster than intermound soils. Soil water potentials on mounds and intermounds at depths of 20 and 30 cm decreased continuously from January until mid-May, and then fluctuated in response to individual rainstorms. Irrigation of 6 mm of water per week had little effect on the soil water potentials except at the 10-cm soil depth of intermound areas. Differences in species composition and biomass production of annual plants between kangaroo rat mounds and intermound areas are attributed to the differences in both soil physical properties and nitrogen availability.

}, keywords = {annual plant, on k-rat mounds, article, articles, biomass,annual plant, Dipodomys, mound ephemerals, Dipodomys,mound properties, journal, journals, rodent, Dipodomys, soil properties,rodent mounds, technique, ion exchange resin bag}, doi = {10.1016/S0140-1963(18)30850-4}, url = {files/bibliography/JRN00122.pdf}, author = {Hyeong-Tae Mun and Walter G. Whitford} } @article {51627, title = {Field evaluation of relationships between a vegetation structural parameter and sheltered against wind erosion}, journal = {Land Degradation and Rehabilitation}, volume = {2}, year = {1990}, note = {//USDA//LTER II//Listed in LTER3 proposal as citing LTER2 support//updated 08/19/2008}, month = {1990}, pages = {87-94}, abstract = {

Measurements of natural vegetation canopies and of threshold friction velocities for soil movement was made at three arid and semiarid field sites. Threshold friction velocities for the vegetated surface and for bare soil were used to evaluate the partitioning of shear stress between that absorbed by the plant canopies and that absorbed by the soil surface (this potentially causing movement of soil particles). Canopy measurements were used to estimate lateral cover (total frontal-silhouette area per unit ground area), a parameter shown by previous laboratory studies to be a good predictor of shear stress partitioning. The relationship between lateral cover and shear stress partitioning for the field sites agreed with the laboratory results of Gillette and Stockton (1989). Results indicate that the protective influence of vegetative cover against wind erosion can be successfully predicted using simply measurement s of vegetation canopy structure.

}, keywords = {aeolian processes, canopy structure, aeolian processes, roughness elements, aeolian processes, shear stress partitioning, article, articles, desert winds, erosion threshold, Geomet, journal, journals, shear stress partitioning, aeolian processes, soil erosion, wind erosion}, doi = {10.1002/ldr.3400020203}, url = {files/bibliography/JRN00123.pdf}, author = {Musick, H. B. and D. E. Gillette} } @article {51639, title = {Field measurements of the sheltering effect of vegetation on erodible land surfaces}, journal = {Land Degradation and Rehabilitation}, volume = {2}, year = {1990}, note = {//USDA//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1990}, pages = {77-85}, abstract = {

Natural vegetation on erodible land surfaces, such as the loose sandy soils found in the southwestern United States and in Soviet Central Asia, absorbs part of the wind momentum flux (stress) and thus protects the erodible soil to a degree that depends on the geometry of plant distribution and profile. The sheltering effect of natural plants may be expressed as the ration, R, of threshold friction velocity for the bare soil (determined in the laboratory or in specially prepared areas of bare soil in the field) to that for the naturally vegetated surfaced. We used new automated instrumentation to detect erosion thresholds in locations where erosion events are widely separated in time. Measured values of R were low for our most vegetated sites and nearer unity for the sparsely vegetated site.

}, keywords = {aeolian processes, degradation, aeolian processes, desertification, aeolian processes, thresholds, aeolian processes,vegetation effects, article, articles, desert winds, desertification, aeolian processes, Geomet, journal, journals, vegetation, wind erosion, wind erosion, vegetation}, doi = {10.1002/ldr.3400020202}, url = {files/bibliography/JRN00124.pdf}, author = {Stockton, P. H. and D. E. Gillette} } @article {51650, title = {Forage intake responses to winter cold exposure of free-ranging beef cows}, journal = {Applied Animal Behaviour Science}, volume = {23}, year = {1989}, month = {1989}, pages = {75-85}, abstract = {

Winter-foraging behaviors of pregnant, crossbred beef cows grazing Montana native rangelands were examined over a continuous 46-day period in January and February. The objective was to examine daily estimates of two principal grazing behaviorsforage intake and time spent grazingin response to fluctuations in acclimated thermal environments. Sixteen 5-year-old cows (525-575 kg) were fitted with vibracorders to monitor daily grazing time (DGT). Fecal organic matter output was estimated using total fecal collections and a Cr2O3-dilution technique. In vitro organic matter disappearance (IVOMD) was determined from extrusa obtained from four rumen-fistulated cows. Mean daily forage intake expressed as a percentage of body weight day (\% BW per day) increased (P\<0.05) when present day ambient air or wind-chill temperatures deviated (either an increase or a decrease) from temperature averages of 1, 2 or 3 previous days, but the magnitude of response was small (\<0.0005\% BW per day per {\textdegree}C deviation). Daily intake was unresponsive (P\>0.05) to deviations from acclimated temperatures calculated for the previous 4-20 days. Dietary extrusa IVOMD averaged 34.5\% and remained consistent (P\>0.05) during the winter grazing period. Daily grazing time decreased (P\<0.05) with ambient or wind-chill temperature deviations from acclimated thermal regimes of the past 1-3 days, and the magnitude of response was also small (\<0.01 h per day per {\textordmasculine}C deviation). The slight responses of these two principal foraging behaviors indicated thermal fluctuations (8 to -16{\textdegree}C) within a familiar winter environment were minimally stressful with no resulting adverse effects upon the animal.

}, doi = {10.1016/0168-1591(89)90008-7}, url = {/files/bibliography/699.pdf}, author = {Beverlin, S.K. and Kris Havstad and E.L. Ayers and M.K. Petersen} } @article {51702, title = {A field guide to the flora of the Jornada plain}, year = {1988}, note = {//NMSU,USDA//NONE//}, month = {1988}, pages = {145}, institution = {New Mexico Agricultural Experimental Station}, address = {Las Cruces, New Mexico}, abstract = {This field guide is intended as an aid in the indentification of the vascular plants of the College Ranch (New Mexico State University) and the Jornada Experimental Range (USDA). Lying at the southern end of the Jornada del Muerto (Journey of Death) in Dona Ana county, the area is bounded on the west by the Rio Grande and on the east by the San Andres Mountains. I have included the entire College Ranch (63,000 acres) but only the plains area of the Jornada Experimental Range (152,000 acres), and not the foothills of the San Andres Mountains. Elevation ranges from 3990 feet at the Rio Grande to 5835 feet at the peak of Summerford Mountain. Annual precipitation averages approximately 8-9 inches, with about half falling in July, August, and September. Average temperatures vary from 60 degrees farenheit in June to 40 degrees farenheit in January. The vegetation of the plains areas is characterized by honey mesquite (Prosopis glandulosa), snakeweeds (Gutierrezia species), and soaptree yucca (Yucca elata) on sandy soils, creosote-bush (Larrea tridentata) on gravely hills and uplands, and tarbush (Flourensia cernua) on the clay flats. On the uplands and hills of the Dona Ana Mountains, the steep, rocky terrain is dominated by sotol (Dasylirion wheeleri), ocotillo (Fouquieria splendens) and mariola (Parthenium icanum).}, keywords = {book, books, chapter, chapters, list,flora, plant,list, report, reports}, isbn = {Bulletin 739}, author = {Allred, Kelly} } @mastersthesis {51710, title = {Fire effects on vegetation of a northern Chihuahuan Desert grassland}, year = {1988}, note = {//NMSU//LTER I//}, month = {1988}, pages = {170}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {It has been hypthesized that fire was important in maintenance of southwestern US grasslands, and that decreased fire frequency and intensity caused by lower fuel levels from livestock grazing may be one cause of desertification of these desert grasslands. This research examines fire effects in a black gramma (Bouteloua eriopoda) grassland, and assesses the potential historical role that fire may have had in these grasslands.... The results suggest that fire was not important in maintenance of black gramma Chihuahuan Desert grasslands. Instead a widespread, intense fire would likely have been a severe disturbance that could have caused decreased abundance of grasses and increased abundance of shrubs, thus possibly enhancing desertification rather than preventing it.}, keywords = {Bouteloua,fire, dissertation, dissertations, fire,grassland, grassland,fire, theses, thesis}, author = {Joe M. Cornelius} } @article {51718, title = {Fecal indicators of cattle protein status on desert grassland range}, journal = {Nutrition Reports International}, volume = {37}, year = {1988}, month = {1988}, pages = {137-147}, abstract = {

Fecal indices. particularly fecal nitrogen concentration, have shown potential as indicators of diet quality of grazing cattle. Our study evaluated the utility of fecal nitrogen concentration and several other fecal chemical characteristics as indicators of protein status of cattle grazing southcentral New Mexico rangelands. Five esophageal fistulated steers and six steers equipped with fecal collection bags were used to evaluate diet quality. forage intake and fecal chemical composition for six collections during a 12-month period in 1984. Fecal phosphorus concentration was highly correlated with diet crude protein concentration (r2=.86). Fecal phosphorus appears to have potential for management decisions concerning protein supplementation. However. because of the lack of other research, we advocate further study before it is applied as a management tool to other ranges. Fecal nitrogen concentration was also correlated with diet crude protein concentration (r2=.67). Fecal phosphorus concentrations below 0.20\%, and fecal nitrogen concentrations below 1.20\% organic matter basis would indicate diet crude protein concentrations below those required for maintenance (7.7\%, organic matter basis) on the range studied. Soluble phenolics and tannins associated with some forbs and shrubs can elevate fecal nitrogen concentrations relative to those in the diet. Based on insoluble fecal nitrogen concentrations. this was not a problem during periods of high (more than 50\% of the diet) forb and shrub consumption in our study.

}, url = {/files/bibliography/331.pdf}, author = {M.D. Hakkila and Jerry L. Holechek and Wallace, J.D. and D.M. Anderson and Manual Cardenas} } @article {51728, title = {Factors affecting phosphate sorption and phosphate retention in a desert ecosystem}, journal = {Soil Science}, volume = {146}, number = {3}, year = {1988}, note = {//NMSU//LTER I//}, month = {1988}, pages = {160-167}, abstract = {

In a study of soils from a chronosequence in southern New Mexico, where CaCO3 accumulation is primarily derived from aeolian input, P adsorption was greatest in the most highly calcic horizons and least in horizons of clay and oxyhydroxide accumulation. Similarly, adsorption capacity was most highly correlated with CaCO3 content. Iron and Al oxyhydroxide contents increased with increasing soil age, and absolute levels were as high as in calcareous soils developed in more humid conditions. Calcium carbonate appears to be the primary geochemical agent capable of the fixation and retention of P within the soil profile in this ecosystem.

}, keywords = {article, articles, biogeochemistry, calcium carbonate, chronosequence, journal, journals, phosphate retention, phosphate sorption, phosphorous, soil, also SEE , soil, aluminim hydrous oxides, soil, chronosequence, soil, iron hydrous oxides}, url = {files/bibliography/JRN00079.pdf}, author = {Kate Lajtha and Bloomer, Sherman H.} } @article {51753, title = {Factors influencing infiltrability of semiarid mountain slopes}, 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 = {197-206}, abstract = {

The objective of this research was to determine the effects of selected vegetation, soil, rock, and slope variables on infiltration of semiarid rangelands with slope gradients ranging from 0-70\%. Analyses were made on 2 sets of data collected a year apart in the Guadalupe Mountains of New Mexico and consisted of Pearson and partial correlation analysis of the dependent infiltration variables and independent site variables. In addition, infiltration was regressed against uncorrelated factors produced by factor analysis. Vegetal cover and biomass strongly influenced infiltration. The relative importance of grasses, shrubs or litter was dependent on their respective abundance, especially grass. Soil depth also limited infiltration especially as soil water storage became satisfied. Infiltrability was negatively correlated with rock cover and the smallest rock size fragments were the most negatively related. When the effects of vegetal cover and slope were removed (using partial correlation analysis) however, the median sized rock fragments (26-150 mm) were positively related to infiltrability, and the smallest rock fragments (2-12 mm) were negatively related. Partial correlation analysis also suggested a positive correlation between infiltrability and slope gradient.

}, keywords = {infiltration, rangeland hydrology, soil water}, doi = {10.2307/3899167}, url = {/files/bibliography/340.pdf}, author = {Wilcox, B.P. and Wood, M. K. and J.M. Tromble} } @article {51772, title = {Field-scale tebuthiuron application on brush-infested rangeland}, journal = {Weed Technology}, volume = {1}, year = {1987}, month = {1987}, pages = {323-327}, abstract = {

The objective of this study was to determine the effectiveness of tebuthiuron \ {N- [5-(1,1-dimethylethyl)-1, 3,4- thiadiazol- 2- yl) -N,N{\textquoteright} -dimethylurea} to treat brush-infested arid rangeland under field-scale conditions. A 130- ha tract in southern New Mexico dominated by creosotebush \ [Larrea tridentata (Sesse \& Moe. ex DC.) Coville $\#$3 LARTR] was treated with pelleted tebuthiuron at 0.4 kg ai/ha. After the fourth season following treatment, control of creosotebush, honey mesquite (Prosopis glandulosa Torr. $\#$ PRCJG), and tarbush (Flourensia cernua DC. $\#$ FLOCE) was 87, 48, and 100\%, respectively. Total shrub density was reduced from 4440 plants/ha to 570 plants/ha. Grass basal area increased from 1.1 to 3.4\%. The treatment did not affect forbs greatly. Total herbaceous above-ground biomass production in the fourth season after treatment was 860 kg/ha compared to 140 kg/ha on an adjacent untreated area. Perennial grass production was nearly 11- fold greater on the treated area than on the untreated area.

}, keywords = {arid rangeland, FLOCE, Flourensia cernua, grass cover, Larrea tridentata, LARTR, PRCJG, prosopis glandulosa}, doi = {10.1017/S0890037X00029833}, url = {/files/bibliography/314.pdf}, author = {Gibbens, Robert P. and C.H. Herbel and J.M. Lenz} } @article {51793, title = {Foraging behavior of Uta stansburiana and Cnemidophorus tigris in two different habitats}, journal = {The Southwestern Naturalist}, volume = {32}, number = {4}, year = {1987}, note = {//USDA//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1987}, pages = {427-433}, abstract = {

Foraging behavior of Uta stansburiana and Cnemidophorus tigris was studied in two different habitats in the Chihuahuan Desert. One habitat was \"natural\" Chihuahuan Desert dominated by shrubs. The other habitat had been modified with herbicide and was dominated by sub-shrubs and grasses. Uta stansburiana exhibited no preference for plant species or life forms when foraging in either habitat. Foraging C. tigris preferentially used mesquite (Prosopis glandulosa) and, to a lesser extent, creosotebush (Larrea tridentata) in the natural habitat. In the grass dominated habitat, C. tigris used bush muhly (Muhlenbergis porteri). Cnemidophorus tigris spend more time foraging under plants with large litter accumulations. Shifts in vegetation from grassland to shrubland appear to favor C. tigris.

}, keywords = {article, articles, behavior,lizards, Cnemidophorus, journal, journals, lizard,behavior, lizard,Cnemidophorus, lizard,foraging behavior, lizard,habitat modification, lizard,Uta, Uta}, doi = {10.2307/3671474}, url = {files/bibliography/87-SWNat-Whitford.pdf}, author = {David K. Peterson and Walter G. Whitford} } @conference {51831, title = {Field water regimes of sandy loam soils on arid rangelands of southern New Mexico}, booktitle = {39th Annual Meeting, Society for Range Management}, year = {1986}, month = {1986}, pages = {361}, keywords = {arid rangelands, field water regimes, sandy loam soils}, author = {C.H. Herbel and Gibbens, Robert P.} } @article {JRN54831, title = {Forage intake of rangeland beef cows with varying degrees of crossbred influence }, journal = {Journal of Animal Science}, volume = {63}, year = {1986}, month = {05/30/1986}, pages = {1484-1490}, chapter = {1484}, abstract = {

Forage consumption of free-ranging beef cows for breeds differing in milk production potential was estimated in the summers of 1983 and 1984. Hereford (HH) and 75\% Simmental-25\% Hereford (3S1H) breed groups were used in 1983. In 1984, 25\% Simmental-75\% Hereford (1S3H), 50\% Simmental-50\% Hereford (SH), and 50\% Angus-50\% Hereford (AH) breed groups were added. Six mature (6-or 7-yr-old) lactating cows of these breed groups were used each year. Fecal output was estimated during June, July and August each year using the chromic oxide dilution technique. A correction factor was derived by comparing estimated fecal output values to actual measurements using fecal bags. Monthly forage extrusa collections for in vitro organic matter disappearance determinations were obtained using esophageal-cannulated cows. Breed groups did not differ in body weight (P\>.10) in either year and averaged 549kg. No significant difference in average mean intake expressed as a percentage of body weight per day (\%BW/d) was found between the breeds in 1983. In 1984, important breed group differences were detected (P\<.O1). Average mean intakes for 1S3H, HH, AH, SH and 3S1H were 2.2, 2.3, 2.5, 2.6 and 2.8\% Bw/d, respectively. These results provide an initial basis for evaluation of cow types of differing production potential that are foraging in a restrictive rangeland environment.

}, keywords = {Beef Cows, breeds, rangelands, Voluntary Intake}, url = {https://dl.sciencesocieties.org/publications/jas/pdfs/63/5/JAN0630051484}, author = {M. W. Wagner and Kris Havstad and D. E. Doornbos and E.L. Ayers} } @proceedings {51882, title = {Field water regimes of sandy loam soils on arid rangelands of southern New Mexico}, year = {1985}, month = {1985}, pages = {514-516}, address = {Kyoto, Japan}, abstract = {

There is little information on field measurement of soil water on arid rangelands. Forage production is largely dependent upon adequate water. The soil water potential is characterized for three sandy loam soils during 1957-76 on arid rangelands of southwestern United States. Gypsum-impregnated resistance blocks were placed at soil depths of 10, 25, 41, 61, and 91 cm. The average annual precipitation during the study periods was 244, 265, and 233 mm. At the 10-cm soil depth, the probability of soil water >= -1.5 megapascals during December March was 66, 70, and 68\% at the three sites; during July-September, it was 40, 50, and 49\%, respectively. Factors affecting soil water were: 1) precipitation amount, 2) surface soil characteristics, 3) topography, 4) soil texture, and 5) vegetation type. This information is useful for modeling the range ecosystem.

}, keywords = {precipitaiton, probabilities, soil structure, soil water potential, vegetation}, url = {/files/bibliography/280.pdf}, author = {C.H. Herbel and Gibbens, Robert P.} } @article {51879, title = {Fruit production by Yucca elata Engelm. (Liliaceae) in four Chihuahuan Desert habitats}, journal = {The Southwestern Naturalist}, volume = {30}, number = {2}, year = {1985}, note = {//NMSU//US-IBP//}, month = {1985}, pages = {321-322}, abstract = {Objectives of this study were: 1) to examine the consistency of the reproductive pattern of Yucca elata in 1983 with that of 1973; 2) to compare fruit production in four habitats along a topographic-edaphic gradient, and ; 3) to determine the best means of predicting the number of fruits produced by Y. elata using caudex height, leaf volume, infructescence stalk volume, stalk height, and stalk diameter at base.}, keywords = {article, articles, journal, journals, plant,Yucca, Yucca, fruit production}, author = {Gilstrap Laslei, Roberta J. and J. Ludwig} } @article {51894, title = {The failure of nitrogen and lignin control of decomposition in a North American desert}, journal = {Oecologia}, volume = {65}, year = {1985}, note = {//NMSU//NONE, LTER//}, month = {1985}, pages = {382-386}, abstract = {

We measured mass losses of both buried and surface litter of six litter types: leaves of the perennial evergreen shrub, Larrea tridentata, leaves of the winter deciduous perennials Flourensia cernua, Prosopis glandulosa and Chilopsis linearis ( a desert riparian species), and evergreen monocot, Yucca elata, and a mixture of annual plants. These species differed in lignin content and carbon-nitrogen ratios. There was no correlation between rates of mass loss and percent lignin, carbon-nitrogen ration, or lignin-nitrogen ratio. The leaves of F. cernua and the mixed annuals exhibited the highest rates of mass loss. Surface litter of Y. elata, and the mixed annuals and C. linearis exhibited higher mass loss than buried litter of the same species. The patterns of mass loss occurring as a negative exponential and surface litter exhibiting low rates in winter and spring and high rates in summer. There was no correlation between mass loss in surface bags that were field exposed for 1 month and actual evapotranspiration (AET) but there was a correlation between AET and mass losses in buried litter. A model relating mass loss to AET and initial lignin content underestimated mass losses in all species examined.

}, keywords = {article, articles, decomposition,lignin, decomposition,litter, decomposition,nitrogen, journal, journals, lignin,decomposition, litter decomposition, model,mass loss, model,Meentemyer, nitrogen,decomposition}, doi = {10.1007/BF00378913}, url = {files/bibliography/JRN00026.pdf}, author = {Douglas Schaefer and Yosef Steinberger and Walter G. Whitford} } @mastersthesis {51987, title = {The foraging ecology of nesting black-throated sparrows}, year = {1983}, note = {//NMSU//NONE//}, month = {1983}, pages = {52}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {The foraging ecology of the Black-throated Sparrow (Amphispiza bilineata) was studied during the breeding season of 1982, on a site in the Chihuahuan Desert of southern New Mexico. Adult sparrows were color-banded and time-activity budgets and space-use were sampled at each of the 12 nests. I recorded distance and direction of foraging patches from the nest, time spent foraging, rate of feeding nestlings, time spent at the nest between trips, and prey type and load size delivered to the nest.}, keywords = {bird, Black-throated Sparrow, bird,Amphispiza,Black-throated sparrow, bird,foraging, Black-throated sparrow, foraging, Black-throated sparrow, nesting, Black-throated sparrow,food habits, dissertation, dissertations, theses, thesis}, author = {Zimmer, Kevin Jay} } @article {52000, title = {Factors affecting the applicability of the AET model for decomposition in arid environments}, journal = {Ecology}, volume = {63}, number = {2}, year = {1982}, note = {//OTHER//NONE//}, month = {1982}, pages = {579-580}, abstract = {

There is considerable interest in the applicability of the model developed by Meentemeyer (1978), which predicts decomposition as a function of actual evapotranspiration (AET) and lignin, to environments other than forests. Whitford et al. (1981b) discussed exceptions to the Meentemeyer AET model in deserts and clearcut forests and concluded that in these environments, biological activity of soil microarthropod and termites, accounts for the deviations (higher rates) from the model. We recently completed a study of decomposition in a semiarid desert-grassland transitional area that provides another independent test of the AET model.

}, keywords = {article, articles, decomposition, AET model, journal, journals, model,actual evapotranspiration, model,AET, model,decomposition}, doi = {10.2307/1938973}, url = {files/bibliography/82-Ecology-Whitford.pdf}, author = {Ned Z. Elkins and Yosef Steinberger and Walter G. Whitford} } @article {52002, title = {Floral visitation by Chihuahuan Desert ants}, journal = {Journal of Natural History}, volume = {16}, year = {1982}, note = {//NMSU//NONE//}, month = {1982}, pages = {879-881}, abstract = {

Experimental and observational tests with tropical lowland plant species and ants have generally rejected Janzen\&$\#$39;s (1977) hypothesis of deterrent chemicals in floral nectars.... Here we address the following two questions for desert plants: (1) do ants naturally visit desert flowers for floral nectar:, and (2) are floral nectars of desert plants repellent to ants?

}, keywords = {ant, floral nectar, ant, floral visitation, ant,foraging strategy, article, articles, journal, journals}, doi = {10.1080/00222938200770701}, url = {files/bibliography/82-JrnofNatHistry-Whitford.pdf}, author = {Harold G. Fowler and Walter G. Whitford} } @proceedings {52039, title = {Flexible grazing based on weather}, year = {1981}, month = {1981}, pages = {205-210}, publisher = {Texas Agriculture Extension Service}, address = {Del Rio, TX}, abstract = {

By grazing or browsing the forage produced on rangelands with livestock and wildlife in a planned and well managed scheme: the range resources enhanced animal production is optimized; and the soil, plant, and water resources are maintained or improved. If these resources are mismanaged to a point where plant cover is not providing sufficient soil cover, and species composition of the plant communities is changed, then productivity and soil protection on the unit is reduced. Continued abuse results in soil erosion problems. This does not imply that proper grazing is destructive. Some of our native range communities have evolved over thousands of years along with grazing use by native animals. However, the plant communities that have evolved are not always the most productive under intensive livestock grazing, e.g., production can be increased on some sites by the use of improved range plants.

}, url = {/files/bibliography/198.pdf}, author = {C.H. Herbel} } @article {52065, title = {Foraging ecology of seed-harvesting ants, Pheidole spp in a Chihuahuan Desert ecosystem}, journal = {The American Midland Naturalist}, volume = {105}, number = {1}, year = {1981}, note = {//NMSU//US-IBP//}, month = {1981}, pages = {159-167}, abstract = {

Seasonal activity, factors affecting foraging activity and forage selection were studied in three species of Pheidole (Hyminoptera: Formicidae) on a watershed in the southern New Mexico Chihuahuan Desert. Pheidole spp. exhibited a seasonal pattern in numbers of active colonies with most colonies active in July coincident with onset of summer rains and seed drop by annual plants. Pheidole militicida occurred only on the deeper soils of the lower watershed while Ph. rugulosa and Ph. xerophila occurred on the entire watershed. The three Pheidole spp. were active only at soil temperatures between 15-35C and were most active at sunrise. Analysis of factors affecting foraging intensity using a stepwise discriminant function and regression showed evaporation and soil surface temperature to be the strongest influences and seed availability to rank second. However, the factors included in the analysis accounted for less than 50\% of the variance in all three species. Pheidole militicida collected mostly forb seeds while Ph. xerophila utilized primarily grass seeds, especially the seeds of fluff grass Erioneuron pulchellum.

}, keywords = {ant, foraging, ant, Pheidole, ant, seed-harvesting, article, articles, journal, journals, Pheidole,foraging}, doi = {10.2307/2425021 }, url = {files/bibliography/81-TheAmMidNtlt-Whitford.pdf}, author = {Walter G. Whitford and D. J. DePree and Hamilton, Patrick and George Ettershank} } @mastersthesis {52067, title = {Feedlot performance and carcass characteristics of Charolais, Hereford and Brangus crossbred cattle}, year = {1981}, note = {//NMSU//NONE//}, month = {1981}, pages = {81}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {cattle,breeding, cattle,productivity, dissertation, dissertations, theses, thesis}, author = {Jamie Fred Williams} } @mastersthesis {52078, title = {Factors effecting production of Brangus under semi-desert conditions}, year = {1980}, note = {//??//NONE//}, month = {1980}, pages = {78}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {cattle,productivity, dissertation, dissertations, theses, thesis}, author = {Coulibaly, Mamadou} } @article {52079, title = {From truck to well puller}, journal = {Rangelands}, volume = {2}, number = {2}, year = {1980}, month = {April 1, 1980}, pages = {51-52}, abstract = {In south-central New Mexico, as in many arid areas, water wells are the main source of water for livestock. On the Jornada Experimental Range, a 190,000-acre range and livestock research facility located north of Las Cruces, NM, a major maintenance problem is the replacement of pump leathers and cylinders of the 14 water wells that are 300 to 400 feet deep. In former years, the wells were repaired by using sheave assemblies and a cable attached to a vehicle that provided lifting power when driven away from the well. Although effective, this method was neither efficient nor safe. Jornada personnel decided to build a winching apparatus that would reduce the time needed to pull a well, the safety hazards, and the physical strain on workers. The result of this endeavor is a well-pulling unit that can be constructed at low cost, saves labor, and is far less hazardous to use. The well-pulling unit was made by modifying a 1-ton truck chassis with cab and engine. The basic concept was to use the engine and transmission to supply power to a double-drum winch made from the rear axle assembly. The first step was to remove the rear axle and bolt it on top of the frame behind the cab. The axle was placed so the front part of the two-part drive line could be connected to the differential using parts of the original universal joints. To make both sides of the axle assembly pull simultaneously, the spider gears in the differential were welded together. Wheel mounts and brake assemblies were left intact since the wheel mounts provided an easy means of attaching winch drums and the brake assemblies provided a ready-made, winch drum-braking system. A cable spool was made from a 1-ft length of 12-inch pipe and two 5-inch flanges made from 1/4-inch plate steel. This spool was welded to the outside of one 20-inch truck wheel which was attached to the wheel mounts on one side of the axle assembly. The 12-inch spool holds 150 ft of 34-inch cable and the lips of the wheel itself form a drum which will hold 150 ft of reserve cable. This winch drum is used as the pipe and sucker rod lifter. Using a crown sheave in the well tower and a single line direct pull (1-1 lifting ratio), 5,000 lb can be raised safely.}, keywords = {livestock, truck chassis, water wells, well repair, well-pulling unit}, url = {/files/bibliography/179.pdf}, author = {Coupland, J.W. and Yarbrough, C.C. and E.L. Garcia} } @mastersthesis {52090, title = {Factors affecting seed germination and seedling establishment of broom snakeweed}, year = {1980}, note = {//NMSU//NONE//}, month = {1980}, pages = {101}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {A study was conducted to test the effects of scarification, stratification, scorching, leaching and soaking treatments on broom snakeweed (Xanthocephalum sarothrae) germination. Broom snakeweed litter and aqueous extracts of this litter were applied to seeds of broom snakeweed and associated species under growth chamber and greenhouse conditions. Broom snakeweed germination responded best when no physical modification of the seeds occurred. Mean germination of water-soaked seeds was 55\%. Scarification did not reduce germination, but all other physical treatments resulted in substantially lower germination. Results of broom snakeweed litter treatments were inconclusive, probably due to slow leaching of potential chemical inhibitors from the plant material. However, aqueous extracts of broom snakeweed litter reduced germination and shoot and root length of blue grama (Bouteloua gracilis) and sideoats grama (B. curtipendula), when applied at concentrations that represented natural litter fall from broom snakeweed canopy covers of 20\% or greater. Allelopathy may be a factor whereby broom snakeweed reduces grass production and enhances its own life cycle.}, keywords = {dissertation, dissertations, plant, snakeweed, plant, Xanthocephalum, toxicity, seed, germination, seedling establishment, snakeweed, SEE Xanthocephalum, theses, thesis, toxicity, snakeweed, Xanthocephalum, Xanthocephalum, germination}, author = {Jeffcoat, B. Lowell} } @inbook {52111, title = {Feed production}, booktitle = {Animal Agriculture, Research to Meet Human Needs in the 21st Century}, year = {1980}, month = {1980}, pages = {153-191}, publisher = {Westview Press}, organization = {Westview Press}, address = {Boulder, CO}, abstract = {

One of the primary constraints to animal production is an adequate supply of feed. As the world human population increases, with consequently increased demand for animal products (especially proteins) in the human diet, there must be increases and improvements in the supply of feed for animal production.

Much of the improvement in animal productivity of meat and milk that has taken place in the U.S. during the past 2 or 3 decades has resulted from extensive use of feed grains. Attention should continue to be given to feed grain production because of its importance, with emphasis on the potential for genetic improvement by plant breeders. There is evidence, however, which suggests that the importance of grain as a feed base maybe declining and that its place, especially for ruminant animals, will be taken, to an increasing degree, by forage or alternate feed sources. Other uses of grains, including their export as an international trade item and their domestic use as a fermentation base for liquid fuel production, as well as decreased demand for lean meat, all contribute to this trend.

There is also an increasing emphasis on conservation of resources, which will increase the cost of land and water and the inputs required for feed grain and forage production. Excessive soil loss from mismanaged cropping is coming under increasing criticism and regulation.

Given that animal production systems in the 21st century will be subject to higher energy costs and that instability will result from alternate demands for a limited supply of grain crops, the exact type of enterprise for the future cannot be predicted. Yet the forces impinging on feed production for animals could lead to a new era in which the animal production systems are part of the total resource conservation for nutrients, water, soil and energy, while producing the feed needed.

}, url = {/files/bibliography/189.pdf}, author = {Wedin, W.F. and Hodgson, H.J. and Oldfield, J.E. and Frey, K.J. and Deyoe, C.W. and Emery, R.S. and Hahn, L. and V.W. Hays and C.H. Herbel and Hillman, J. . and Klopfenstein, T.J. and Larson, W.E. and Lechtenberg, V.L. and Marten, G.C. and Moe, P.W. and Polin, D. and Sweeten, J.M. and Templeton, W.C. and Van Soest, P.J. and Vetter, R.L. and Waldrip, W.J.}, editor = {Pond, W.G. and Merkel, R.A. and McGilliard, L.D. and Rhodes, V.J.} } @article {52112, title = {Foraging ecology of two Chihuahuan Desert ant species: Novomessor cockerelli and Novomessor albisetosus}, journal = {Insectes Sociaux}, volume = {27}, number = {2}, year = {1980}, note = {//NMSU//US-IBP//}, month = {1980}, pages = {148-156}, abstract = {

Novomessor albisetosus and N. cockerelli foraged most intensively in the evening and morning at soil surface temperatures between 20 C and 40 C. They were not active in the middle of the night and mid-day. In both species, colonies provided with supplementary seeds increased their foraging intensity. N. cockerelli colonies which were provided with high protein food (tuna fish) extended their foraging time and remained active until soil surface temperatures reached lethal levels. Nearly half of the natural forage of N. cockerelli was insects or insect parts which accounted for only 6.6\% of the forage of N. albisetosus. Approximately 10\% of the workers of N cockerelli entered and were apparently accepted by colonies other then their \"home\" colony. This study demonstrates the importance of both forage availability and forage quality as determinants of activity and forage selection of Novomessor sp.

}, keywords = {ant, Novomessor, ant,foraging, article, articles, foraging,ant, journal, journals, Novomessor,foraging}, issn = {0020-1812}, doi = {10.1007/BF02229250}, url = {files/bibliography/80-Insectes Sociaux-Whitford.pdf}, author = {Walter G. Whitford and Elaine DePree and P. Johnson} } @article {52160, title = {Factors affecting growth curve parameters of Hereford and Brangus cows}, journal = {Journal of Animal Science}, volume = {46}, number = {3}, year = {1978}, note = {//NMSU//NONE//}, month = {1978}, pages = {604-613}, abstract = {Brody{\textquoteright}s model was used to fit individual growth curves to 74 Hereford and 83 Brangus cows, born in 2 consecutive years and located in two distinct New Mexico range environments. The effects of year of birth, ranch, breed, pregnancy status at 43 months of age and their interactions on growth curve parameters, weights and weight estimates were analyzed. A phenotypic antagonism between mature weight and rate of maturing was found in both breeds, indicating that earlier maturing heifers would have lighter mature weights than late maturing females.}, keywords = {article, articles, cattle, environmental factors, cattle, growth curve, journal, journals, model, Brody}, author = {Lopez de Torre, Guillermo and B. J. Rankin} } @proceedings {52152, title = {Factors affecting fruit fill and seed germination of fourwing saltbush (Atriplex canescens (Pursh) Nutt.)}, volume = {Volume 1}, year = {1978}, note = {//USDA//NONE//ProCite field[6]: In}, month = {1978}, pages = {403-405}, abstract = {Fourwing saltbush exhibits wide variation among plants and among sites in fruit fill, seed germination, and fruit germination. Total annual rainfall or combinations of rainfall by months did not serve to predict fruit fall, fruit germination, or seed germination. Abundance of fruit produced per plant was of no value in predicting these characteristics.}, keywords = {abstract, abstracts, Atriplex, germination, conference, conference proceedings, conferences, germination, Atriplex, plant, Atriplex, plant,fourwing saltbush, Atriplex, proceeding, proceedings, seed, Atriplex}, author = {J. B. Gerard}, editor = {D. H. (ed.) Hyder} } @article {52162, title = {Factors affecting fall weights of Brangus and Hereford cows in southern New Mexico}, year = {1978}, note = {//??//NONE//}, month = {1978}, institution = {New Mexico Agricultural Experiment Station}, keywords = {book, books, cattle grazing, chapter, chapters, grazing management, report, reports}, isbn = {Research Report 366}, author = {B. J. Rankin and Torres-Hernandez, C.} } @article {52167, title = {Factors affecting the nesting success of the large carpenter bee, Xylocopa californica arizonensis}, journal = {Environmental Entomology}, volume = {7}, year = {1978}, note = {//NMSU//US-IBP//}, month = {1978}, pages = {614-616}, abstract = {

The nesting success of Xylocopa californica arizonensis Cresson (Hymenoptera:Anthophoridae) is determined primarily by the availability of pollen and nectar and by the presence of a source of nest substrate. X. c. arizonensis appears to depend upon the pollen of Larrea tridentata or Prosopis spp. for larval food, when it is available. Predators, parasites and nest competitors are relatively unimportant in limiting nesting success.

}, keywords = {article, articles, insect,carpenter bee,Xylocopa, journal, journals, Xylocopa,nesting success}, url = {files/bibliography/78-EnvrmntlEntmlgy-Whitford.pdf}, author = {W. E. Smith and Walter G. Whitford} } @article {52166, title = {Further studies on growth patterns in Yucca elata Engelm (Liliaceae)}, journal = {The Southwestern Naturalist}, volume = {23}, number = {1}, year = {1978}, note = {//NMSU//US-IBP//}, month = {1978}, pages = {145-150}, abstract = {In a previous study on growth patterns in Yucca elata on the Jornada Range in southern New Mexico, it was observed that an individual Yucca elata grows in a cyclic pattern with respect to leaf and inflorescence production. Results of this study confirm that observation. A large individual plant does not produce an inflorescence stalk every year in the field, an influence of both climatic patterns and plant age and vigor. The cyclic pattern of growth is due to its ability to store large amounts of energy, which is then depleted during the production of the high energy-cost inflorescence. Because of this, intervening years of strictly vegetative growth are necessary, after which an individual plant will flower again give appropriate environmental conditions. A small, young plant must grow several years before it can reproduce. Other woody monocots in the northern Chihuahuan desert appear to exhibit similar growth patterns as Yucca elata.}, keywords = {article, articles, journal, journals, Yucca,growth patterns}, author = {Stanley D. Smith and J. Ludwig} } @proceedings {52172, title = {Foraging by seed-harvest ants}, year = {1978}, note = {//NMSU,USDA//NONE//ProCite field[6]: In}, month = {1978}, pages = {107-110}, publisher = {Cambridge University Press}, abstract = {A review of published studies on the foraging of seed-harvesting ants.}, keywords = {abstract, abstracts, ant, foraging, ant, Novomessor, ant, Pogonomyrmex, ant, Veromessor, conference, conference proceedings, conferences, food habits, also SEE , insect, also SEE , proceeding, proceedings}, author = {Walter G. Whitford}, editor = {Brian, M. V. (ed.)} } @article {52174, title = {Foraging in seed-harvester ants, Pogonomyrmex spp}, journal = {Ecology}, volume = {59}, number = {1}, year = {1978}, note = {//NMSU//US-IBP//}, month = {1978}, pages = {185-189}, abstract = {

Pogonomyrmex rugosus, a group forager, foraged preferentially on seeds of plant species which shed large quantities of seeds a 1 time. Pogonomyrmex desertorum, an individual forager took seeds in relation to their availability but concentrated on grass seeds late in the growing season. Pogonomyrmex californicus selected seed species which allowed it to avoid contact with its congeners. During a dry year, P. rugosus exhibited little selectivity, supporting the idea that selectivity should be decreased under conditions of low food abundance. Pogonomyrmex spp. removed a significant fraction of the seed production of only 1 species, Bouteloua barbata. It is suggested that Pogonomyrmex foraging may affect the relative abundance of plant species.

}, keywords = {ant, competition, ant, seed production, ant,foraging, ants, seed selection, article, articles, food habits,ants, journal, journals, Pogonomyrmex,competition, seed, production, seed, selection}, doi = {10.2307/1936647 }, url = {files/bibliography/78-Ecology-Whitford.pdf}, author = {Walter G. Whitford} } @article {52185, title = {Factors influencing the distributions of two species of Perognathus}, journal = {Ecology}, volume = {58}, year = {1977}, note = {//NMSU//US-IBP//}, month = {1977}, pages = {877-884}, abstract = {

Perognathus penicillatus and Perognathus intermedius were studied in two areas in Dona Ana County, New Mexico, from 1970-1972. Perognathus penicillatus was associated with sandy soils and P. intermedius with soils composed of predominantly larger particles. Soils from areas where P. intermedius was found had a lower heat buffering capacity than soils from areas occupied by P. penicillatus. Artificial burrows when occupied by either species had a higher concentration of CO2 in P. intermedius type soils. Perognathus penicillatus occupied burrows in cooler places, survived a narrower temperature range, and exhibited higher rates of evaporative H2O loss with increased ambient temperature and CO2 concentration than did P. intermedius. Perognathus penicillatus was the more aggressive species, and dominated P. intermedius in laboratory encounters.

}, keywords = {article, articles, journal, journals, Perognathus, respiration, rodent, behavior, rodent, competition, rodent, distribution, rodent, Perognathus, rodent, thermoregulation}, doi = {10.2307/1936223}, url = {files/bibliography/77-Ecology-Whitford.pdf}, author = {Kenneth D. Hoover and Walter G. Whitford and P. Flavill} } @mastersthesis {52192, title = {Factors affecting the nesting success of the large carpenter bee, Xylocopa californica arizonensis Cresson}, year = {1977}, note = {//NMSU//US-IBP//}, month = {1977}, pages = {25}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Nest density and nesting success of Xylocopa californica arizonensis is primarily determined by nest substrate availability and pollen and nectar availability. X. californica arizonensis appears to primarily depend on pollen from Larrea tridentata or Prosopis spp. for larval food. Principal predators and parasites are a little importance in determining nesting success. Nest competitors and nest inquilines are common but do not appear to have a limiting effect on nesting success.}, keywords = {dissertation, dissertations, insect,carpenter bee,Xylocopa, theses, thesis, Xylocopa,nesting success}, author = {W. E. Smith} } @article {52202, title = {Feeding-season production in the desert millipede Orthoporus ornatus (Girard) (Diplopoda)}, journal = {Oecologia}, volume = {24}, year = {1976}, note = {//??//NONE//}, month = {1976}, pages = {265-276}, keywords = {arthropod,millipede, arthropod,Orthoporus, article, articles, journal, journals, Orthoporus}, author = {Crawford, C. S.} } @mastersthesis {52225, title = {Factors affecting dystocia in range beef heifers}, year = {1975}, note = {//NMSU//NONE//}, month = {1975}, pages = {68}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Fifty-five primiparous heifers belonging to the Brangus, Hereford, Brangus X Hereford and Hereford X Brangus breeds were used to study factors affecting dystocia. Characteristics of the dam including height, weight, measurements between the hook bones, hook and pin bones, pin bones, horizontal and vertical pelvic dimensions and pelvic area were measured in October, December and February. Calf sex and individual calf measurements including head width, shoulder width and birth weight were determined within 24 hours after birth. Correlations for the three periods of measurement suggested less dystocia for progressively larger framed and heavier dams. Dam body weight had significant negative correlations (P<.05) to dystocia for the three times of measurement. Dam height was found to have significant negative correlations (P<.01) and (P<.05) to dystocia for December and February. Only when taken in December did the hook-pin measurement have a significant negative correlation (P<.05) to dystocia, and only when taken in February did the hook-hook measurement have a significant negative correlation (P<.01) to dystocia. Pelvic area was significantly correlated (P<.01) to dystocia when pelvic area was obtained in December or February. Stepwise regression for each of the three months of measurement indicated a more reliable prediction of dystocia the closer to term the variables are considered. Thirty-eight percent, 43\% and 45\% of the variation in dystocia score for October, December and February, respectively, was accounted for in the regression equations.}, keywords = {cattle breeding, dystocia, cattle reproduction, dystocia, disease,dystocia, dissertation, dissertations, dystocia, reproduction, also SEE , theses, thesis}, author = {Cadle, Joseph Mark , Jr.} } @article {52235, title = {Foraging ecology and relative importance of subterranean termites in Chihuahuan desert ecosystem}, journal = {Environmental Entomology}, volume = {4}, number = {1}, year = {1975}, note = {//NMSU//US-IBP//}, month = {1975}, pages = {66-70}, abstract = {

Foraging activity of subterranean termites was studied on grids of artificial food units (toilet paper rolls) and on natural foods on the surface using belt transects. Preferred forage items were portions of Yucca elata logs and cattle dung which provided large surface area contact with the soil. Foraging at the surface occurred at soil temperatures \> 3-5 degrees Celsius at 15 cm depth and at soil moisture tensions between 0 and minus 140 bars. Estimated foraging group densities were 440/ha and 61/ha for 2 areas. Differences in foraging group densities were related to soil texture and depth above the caliche. Mid-summer field determined consumption rates were 7.9+-2.8 and 1.2+-0.04 kg/ha on the 2 study areas. We concluded that termites account for the consumption of ca. 50\% of the production in creosotebush and mesquite-yucca grassland communities in the Chihuahuan desert.

}, keywords = {article, articles, decomposition, termites, foraging ecology, termites, journal, journals, termite, foraging ecology}, doi = {10.1093/ee/4.1.66}, url = {files/bibliography/75-EnvironEntom-Whitford.pdf}, author = {Johnson, Kimberly A. and Walter G. Whitford} } @mastersthesis {52250, title = {Foraging and breeding behavior of the black-tailed gnatcatcher (Polioptila melanura) in southern New Mexico}, year = {1975}, note = {//LOCAL//NONE//}, month = {1975}, pages = {36}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Black-tailed Gnatcatchers (Polioptila melanura) were studied throughout 1974 in a southern New Mexico desert and on several visits in a southern Arizona desert. The study concentrated on foraging ecology, reproduction, and vocalizations. Timed foraging activities totaled 35,704 sec for both areas combined. Foraging vegetation was apparently chosen according to the volume of foliage on a bush. Foraging beat was varied with changes in prey availability. Gleaning was the major foraging tactic, with hawking and hovering being used to a much lesser degree. The foliage-gleaning guild on the main study area consisted of three species, which apparently minimized competition by using different strata within a plant or different foraging tactics. Pairing began in early February although nesting did not begin until mid-day.... Gnatcatchers used the "tsh" call most of the time. This call was given in different contexts and apparently had different meanings. Males were also observed giving a song during pairing activities and attempted copulations.}, keywords = {behavior,birds, bird,Black-tailed gnatcatcher,behavior, Black-tailed gnatcatcher,behavior, dissertation, dissertations, Polioptila,behavior, theses, thesis}, author = {Thomas, Kenneth Gary} } @article {52257, title = {Factors affecting foraging activity in Chihuahuan Desert harvester ants}, journal = {Environmental Entomology}, volume = {4}, number = {5}, year = {1975}, note = {//NMSU//US-IBP//}, month = {1975}, pages = {689-696}, abstract = {

The foraging activity of 4 species of harvester ants as affected by soil surface temperature, saturation deficit at the soil surface, light and forage availability was studied in a desert grassland area 40 km NNE of Las Cruces, N.M. Pogonomyrmex sp. were capable of locomotor activity at temperatures between ca. 5 and 53 C and Novomessor cockerelli between 4 and 52 C. Pogonomyrmex sp. exhibited maximum foraging intensity at 45 C and N. cockerelli at 20 C. Forager population sizes varied among species: 1000-6000 in P. rugosus, ca. 1000 in P. californicus and N. cockerelli; and ca. 200-600 in P. desertorum. P. rugosus exhibited peak foraging activity and had the greatest number of colonies active following drought periods, ceasing foraging when granaries were filled, and foraged at night during midsummer. P. desertorum and P. californicus were strictly diurnal and did not exhibit hoarding behavior. P. desertorum responded to soil wetting by shifting activity between watered and unwatered controls directly in response to differences in soil surface temperature. Soil wetting stimulated intense activity in P. rugosus at a time when controls were inactive. Foraging in harvester ants seemed to be primarily affected by forage availability, secondarily by microclimate, with historical factors and interspecific competition as contributing parameters in some species.

}, keywords = {ant, foraging, article, articles, foraging,ants, journal, journals, Novomessor,foraging, Pogonomyrmex,foraging}, doi = {10.1093/ee/4.5.689}, url = {files/bibliography/75-EnvEnto-Whitford.pdf}, author = {Walter G. Whitford and George Ettershank} } @article {52256, title = {Foraging behavior of Chihuahuan Desert harvester ants}, journal = {The American Midland Naturalist}, volume = {95}, number = {2}, year = {1975}, note = {//USDA//US-IBP//}, month = {1975}, pages = {455-458}, abstract = {

Foraging behavior was studied on a desert grassland site 40 km NNE of Las Cruces, New Mexico. The number of workers foraging decrease logarithmically with distance from colony when individual seeds were evenly distributed and varied directly with seed density. Some colonies of Pogonomyrmex rugosus exhibited group foraging while others did not. Foraging territories of individual colonies of P. rugosus were irregular in shape and overlapped considerably with foraging territories of adjacent colonies of P. rugosus.

}, keywords = {ant,foraging behavior, article, articles, food habits, also SEE , foraging,Pogonomyrmex, harvester ant,SEE , journal, journals, Novomessor,foraging behavior, pogonomyrmex, Pogonomyrmex,foraging behavior}, doi = {10.2307/2424409 }, url = {files/bibliography/75-AmMidldNat-Whitford.pdf}, author = {Walter G. Whitford} } @article {52259, title = {Factors contributing to production and distribution of Chihuahuan desert annuals}, year = {1975}, note = {//??//US-IBP//}, month = {1975}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {annual plant,distribution, annual plant,production, book, books, chapter, chapters, plant, also SEE , report, reports}, isbn = {Research Memorandum 75-11}, author = {P. D. Whitson} } @article {52285, title = {The foraging ecology of two species of Chihuahuan desert ants: Formica perpilosa and Trachyrmyrmex smithi neomexicanus (Hymenoptera Formicidae)}, journal = {Insectes Sociaux}, volume = {21}, number = {3}, year = {1974}, note = {//NMSU//US-IBP//}, month = {1974}, pages = {317-330}, abstract = {

The foraging ecology of two ant species inhabiting the same area in the Chihuahuan desert was investigated by study of conditions and magnitude of forager activity, estimation of forager population numbers, determination of critical maximum and minimum temperatures, and observation of foraging behavior. The foraging activity of Formica perpilosa was relatively independent of soil temperature and saturation deficits probably because of their ability to lose water without detriment and the fact that they forage in plants. Foraging activity in Trachymyrmex smithi neomexicanus ceased at saturation deficits greater than 35 gms/m3 and soil surface temperatures greater than 50 C. The mean critical thermal maxima and minima in F. perpilosa were 45.2 C and 5.2 C and in T. s. neomexicanus were 36.7 C and 9.7 C. The estimated forager population size in F. perpilosa ranged from 2,000 to 3,500 per colony. We estimated that the average forager population size in T. s. neomexicanus was bout one half that of F. perpilosa.F. perpilosa forage on both honey dew and insects. T. s. neomexicanus forage on leaf litter, and appear to exhibit a seasonal change in forage preference.

}, keywords = {ant, foraging ecology, ant, Formica, ant, Trachyrmyrmex, article, articles, foraging ecology, Formica,foraging ecology, journal, journals, Trachyrmyrmex,foraging ecology}, doi = {10.1007/BF02226923}, author = {Aileen Schumacher and Walter G. Whitford} } @mastersthesis {52293, title = {Factors affecting calving interval of Hereford and Santa Gertrudis cows at the Jornada Experimental Range}, year = {1973}, note = {//USDA//NONE//}, month = {1973}, pages = {64}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Data collected on Hereford and Santa Gertrudis cows from 1959 through 1972, at the Jornada Experimental Range, were used for calving interval analyses. Different analyses with specific restrictions on ages and years were used to determine the effects of different factors. Analyses were made on all calving intervals and on consecutive calving intervals. The effect of age at first calving, analyzed separately, was found non-significant. The effects of age at calving, year and sex were analyzed within each breed. Age at calving had a significant effect on both breeds a while year effect was significant in the case of Herefords and not in the case of Santa Gertrudis. Sex did not have a significant effect on either breed. Breed, age and year effects were determined by combining the two breeds. Ages three through seven-year-olds and years 63 through 66 were considered for this analysis. There was a significant breed difference. Herefords averaged 417.08 days while Santa Gertrudis had an average of 461.08 days when all intervals were considered. The figures for the consecutive intervals were 391.45 days for Herefords and 405.53 days for Santa Gertrudis. Age and year had significant effects while sex and the two and three factor interactions were non-significant. Crossbreeding data collected during 1967-1972 were used to determined the effects of breed of sire, year, sex and their interactions. Breed of sire has a significant effects when the consecutive intervals were used but was non-significant in the case of all intervals. Yet, cows bred to bulls of their own breed has shorter intervals than cows bred to bulls of a different breed. Hereford cows bred to Brangus and Santa Gertrudis bulls had 30.4 days and 11.02 days longer intervals respectively than Hereford cows bred to Hereford bulls. Similarly, Santa Gertrudis cows bred to Hereford bulls had 31.93 days longer intervals than Santa Gertrudis cows bred to Santa Gertrudis bulls. Year, again, had a significant effect while there was no significant effect due to sex and the two and three factor interactions.}, keywords = {cattle, breeding, cattle, calving interval, dissertation, dissertations, theses, thesis}, author = {Arrefaine Berhe} } @inbook {52308, title = {Field moisture regimes and morphology of some arid-land soils in New Mexico}, series = {Field Soil Water Regimes}, volume = {Soil Science Society of America, Special Publication No. 5}, year = {1973}, month = {1973}, pages = {119-152}, address = {Madison, WI}, abstract = {Soil moisture, as well as other climatic features, have been recognized as an important factor in soil genesis and classification. Certain soils occur only in specific climatic zones. The water status of soil continually affects soil properties through its influence on weathering, profile development, friability and permeability (Slatyer, 1967). It is also an important factor in erosion on some soils (Russell, 1959). In the system of soil classification (Soil Survey Staff, 1960 and 1967) adopted by the National Cooperative Soil Survey, soil moisture characteristics are used as differentiating criteria. Soil moisture and precipitation data have been collected at a number of sites in an arid region of southern New Mexico. The effects of precipitation on soil moisture depends on such factors as (1) soil characteristics (structure, texture, etc.), (2) position on the landscape, (3) amount and intensity of precipitation event, (4) plant cover and (5) soil moisture status at time of storm. In this paper, we relate soil moisture to precipitation, soil morphology and landscape position.}, keywords = {classification, precipitation, soil moisture, soil morphology}, url = {/files/bibliography/143.pdf}, author = {C.H. Herbel and L. H. Gile}, editor = {Bruce, R.R. and Flach, K.W. and H. M. Taylor} } @article {JRN52694, title = {Factors restricting pronghorn increase on the Jornada Experimental Range}, number = {245}, year = {1973}, month = {1973}, pages = {1-12}, institution = {New Mexico State University}, address = {Las Cruces, NM}, abstract = {

The pronghorn (Antilocapra americana, Ord) is New Mexico\&$\#$39;s third most important game ungulate. In 1963, 90,000 big game hunters spent $16.6 million in New Mexico (26). Approximately $358,000 was spent in pursuit of pronghorns. These numbers may double by 1975 because of the expected increase in population and the increasing percentage of hunters. Because of these hunting increases and additional demands on all phases of outdoor recreation, wildlife managers will be forced to engage in more intensified game management programs. They must find ways to increase carrying capacity of game ranges and increase the production of game herds. The objective of this study was to determine the factors that were restricting pronghorn increase on the Jornada Experimental Range. Even though hunting is not allowed on the area, the basic information gained could be used to improve management of pronghorns on similar areas of the Southwest. If habitat requirements are known, it might be possible to increase pronghorn habitat and numbers through habitat manipulation.

}, keywords = {Jornada Experimental Range, management, pronghorn, Southwest}, issn = {245}, url = {/files/bibliography/146.pdf}, author = {V. W. Howard Jr. and C.T. Engelking and Elmo Dwain Glidewell and J. E. Wood} } @article {52322, title = {Food items foraged by herbivorous ants in a desert ecosystem}, year = {1973}, note = {//??//US-IBP//}, month = {1973}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {ant, herbivorous, ant,diet, book, books, chapter, chapters, herbivory,ants, report, reports}, isbn = {Research Memorandum 73-29}, author = {Walter G. Whitford} } @article {52320, title = {Forager population estimates in a desert ecosystem}, year = {1973}, note = {//??//US-IBP//}, month = {1973}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {book, books, chapter, chapters, forager population, population,forager, report, reports}, isbn = {Research Memorandum 73-29}, author = {Walter G. Whitford} } @article {52316, title = {Foraging intensity of herbivorous ants in a desert ecosystems}, year = {1973}, note = {//??//US-IBP//}, month = {1973}, institution = {Utah State University}, address = {Logan, Utah}, keywords = {ant,foraging, ant,herbivorous, book, books, chapter, chapters, herbivory,ants, report, reports}, isbn = {Research Memorandum 73-29}, author = {Walter G. Whitford} } @conference {52363, title = {Field moisture regimes of some arid-land soils in southern New Mexico}, booktitle = {Agronomy Abstracts}, year = {1971}, month = {1971}, pages = {107}, keywords = {arid land, field moisture regimes}, author = {C.H. Herbel and L. H. Gile} } @mastersthesis {52472, title = {Food habits, habitat preference, reproduction, and diurnal activity in four sympatric species of whiptail lizards (Cnemidophorus)}, year = {1966}, note = {//LOCAL//NONE//}, month = {1966}, school = {New Mexico State University}, type = {M.S. Thesis}, address = {Las Cruces, New Mexico}, abstract = {Niche relationships of four sympatric species of whiptail lizards, Cnemidophorus, were studied during 1964 and 1965, along the Rio Grande near Mesilla, Dona Ana County, New Mexico. Comparisons among Cnemidophorus tigris, C. perplexus, C. exsanguis and C. inornatus were based on size, habitat distribution, food habitats, reproduction, and temperature relationships. Significant size differences exist among the species as well as sexual dimorphism in C. tigris, with males the larger. The distribution of C. tigris and C. perplexus in 1964 remained separate from those of C. exsanguis and C. inornatus, but in 1965 all ranges overlapped. All expanded their ranges, except C. exsanguis, which remained the same. Increased in 1965 with more food probably permitted the increased of usable habitat. Competition for food was not evident between C. exsanguis and C. inornatus. There was a strong possibility of competition, however, between C. tigris and C. perplexus since they occupied the same habitat and had similar food preferences. All species favored Lepidoptera and Coleoptera, but in a dry year Hymenoptera were also ready eaten.Cnemidophorus exsanguis had shorter breeding season, from late June to the end of July, but the other three species are reproductively active from late May to the end of July. Preferred body temperatures of all Cnemidophorus studied were between 39.0 and 40.0 C. These temperatures were attained at different times during the early morning. There are a few differences between the species in seasonal and daily activity, but these differences do not seem to be great enough to allow habitat overlap without competition.}, keywords = {Cnemidophorus, diurnal activity, Cnemidophorus, food habits, Cnemidophorus, habitat preference, Cnemidophorus, reproduction, dissertation, dissertations, lizard, whiptail lizards, lizard,diurnal activity, lizard,food habits, lizard,habitat preference, lizard,reproduction, lizard,sympatric species, reptile, also SEE , theses, thesis}, author = {Medica, Philip Anthony} } @mastersthesis {52477, title = {Factors and treatments affecting fruit fill, seed germination and seedling emergence of fourwing saltbush (Atriplex canescens (Pursh) Nutt.)}, year = {1965}, note = {//NMSU, USDA//NONE//}, month = {1965}, pages = {60}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {The objectives of these studies were to determine factors and treatments affecting fruit fill, fruit and seed germination and seedling emergence of fourwing saltbush (Atriplex canescens (Pursh) Nutt.). These studies indicate that fourwing saltbush exhibits wide variation in fruit fill, seed and fruit germination from plant to plant and from site to site. Total annual rainfall or combinations of rainfall by months did not serve to predict either fruit fill or germinations of fruit fill or germination of fruit or seed. Abidance of fruit produced per plant is also of no value in predicting these characteristics.}, keywords = {Atriplex, germination, Atriplex,reproduction, dissertation, dissertations, germination, Atriplex, seed, Atriplex, theses, thesis}, author = {J. B. Gerard} } @mastersthesis {52481, title = {Form and function of song in a population of Amphispiza bilineata (Cassin)}, year = {1965}, note = {//LOCAL//NONE//}, month = {1965}, school = {New Mexico State University}, type = {M.S. Thesis}, address = {Las Cruces, New Mexico}, abstract = {Structure and function of song were studied in a population of twenty-two Black-throated Sparrows. Audiospectograms were made of eighty songs found in the population; seventy of the songs were used in most of the analyses. Song duration, duration and structure of the parts, frequency limits, and temporal ordering within the song were studied. Nine song types were the most recorded in an individual; the same individual had less variable song duration than the population as a whole. Black-throated Sparrows are highly variable singers, both as individuals and as a population. They are more variable than other emberizines in song duration and minimum frequency and less variable in detailed syllable characteristics. Factors apparently important in the song variation are the lack of closely related sympatric species and reduced numbers of bird species in desert scrub habitat. Large territories appear to encourage selection for overall pattern variation and for vocal versus visual communication maintaining territoriality. Experiments substantiated that territories are defended primarily by vocalization. Individual recognition appears to be through variation in the fine structure of the song, including duration; while species recognition is postulated as being through the overall format of the song and the presence of trills.}, keywords = {Aves, also SEE , Aves, Amphispiza, bird, Black-throated sparrow, song, dissertation, dissertations, theses, thesis}, author = {Heckenlively, Donald Bruce} } @article {52499, title = {Fertilizing tobosa on flood plains in the semidesert grassland}, journal = {Journal of Range Management}, volume = {16}, number = {3}, year = {1963}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {May 1, 1963}, pages = {133-138}, abstract = {Tobosa [Hilariamutica (Buckl.) Benth.], a drought-resistant grass of the arid Southwest, occurs primarily on heavier textured soils but is not limited to them. It is relatively unpalatable to livestock during the dormant season but is readily grazed during the growing season. Therefore, where possible, tobosa flood plains should be fenced separately and grazed during the growing season while the upland pastures are deferred. These flood plains supporting tobosa in high density and receiving additional water as run-in from adjacent mountains can produce several times the herbage of upland sites. On ranches where the area of tobosa flood plains is limited, increased yields of tobosa will enable the operator to defer the upland pastures more completely and for a longer time in the growing season. The objective of this study was to determine tobosa herbage yields and quality on flood plains as influenced by fertilizer treatments in relation to the effects of available moisture.}, keywords = {fertilizer treatments, flood plains, tobosa quality}, url = {/files/bibliography/088.pdf}, author = {C.H. Herbel} } @proceedings {52513, title = {A four-pronged mesquite control program}, year = {1961}, month = {1961}, pages = {20-29}, keywords = {control program, mesquite}, author = {C.H. Herbel} } @article {52569, title = {Flora of the Jornada Experimental Range, New Mexico}, journal = {Copeia}, volume = {4}, year = {1943}, note = {(also in Amer. Midl. Nat. 30:626-670. 1943)}, month = {1943}, pages = {216-222}, abstract = {Various members of the Forest Service made a collection of specimens of 528 species of ferns and seed plants and a few lower plants at Jornada Experimental Range in southern New Mexico during the twenty-five year period from 1915 to 1939. This local herbarium serves as a basis for analysis of the flora and vegetation of this representative semidesert area and has contributed several interesting state records and range extensions. Jornada Experimental Range is located in northeastern Dona Ana County with headquarters 23 miles north of Las Cruces. Occupying 302 square miles (193,394 acres), it is the largest experimental range in the United States. It lies at the southern end of Jornada del Muerto, a plain having a north-south extent of more than 100 miles. The Spanish name Jornada del Muerto means "the day{\textquoteright}s journey of the dead man" but is sometimes translated also as "journey of death." According to Wislizenus (1848), the name refers to an old tradition that the first person that attempted to cross the plain in one day perished. At this point, the banks of the Rio Grande become so rough and mountainous that early travelers going north to Santa Fe were forced to leave them and journey across the desolate, waterless plain a distance of 90 miles.}, keywords = {flora, Jornada Experimental Range, specimen collection}, url = {/files/bibliography/063.pdf}, author = {E. L. Little Jr. and R.S. Campbell} } @article {52645, title = {Factors affecting range management in New Mexico}, year = {1915}, month = {May 26, 1915}, pages = {39 }, publisher = {Government Printing Office}, abstract = {

Stock raising is more patently influenced by and dependent upon its physical environment than most other industries appear to be. The topographic and climatic conditions are fundamental because they determine the kind and quantity of feed the animals must eat, the temperature and other extremes they must endure, and the various dangers which they must avoid. The laws and customs of the region determine the character of the tenure and control of the land that produces the feed upon which the animals subsist. They are but the expression of public opinion that warrants the existence of that industry in that place. And not less important, but probably less often considered, is the relation that the business bears to other industries in operation in the same region. From this standpoint, the industry is to be considered as in a certain stage of development toward a better and more complex adjustment among all industries, and a statement of its present condition must be taken as in the nature of a report of progress. It is not what it once was, nor yet what it will be. Thus, while we are here mainly concerned with the details of the purely physical basis of the industry, the factors of control and relation to other industries are so closely connected with any proper kind of management that they must be considered somewhat at length. A study of range conditions is but preliminary to an understanding of methods of management and the requirements necessary for the further improvement of the industry.

}, keywords = {feed, government publication, range conditions, range management, stock raising}, url = {/files/bibliography/003-1.pdf}, author = {Wooton, E.O.} } @booklet {52646, title = {Flora of New Mexico}, volume = {19}, year = {1915}, month = {June 24, 1915}, pages = {794}, publisher = {Smithsonian Institution, United States National Museum, Contributions from the United States National Herbarium, Government Printing Office}, chapter = {794}, abstract = {This volume of contributions is devoted to flora of New Mexico; only the flowering plants and vascular cryptogams of New Mexico are contained in the present work. Keys are given for the determination of the species, as well as of the larger groups, so the volume may be used as a field manual. At the same time, the citations will enable those who have access to libraries to readily consult the original descriptions of the species. The number of species treated is approximately 3,000. Notwithstanding the large amount of fieldwork already accomplished, many remote districts in New Mexico are still imperfectly known botanically, so that eventually this number will doubtless be increased by several hundred species. The treatise in its present form, however, contains most of the plants growing spontaneously in those parts of the state thus far settled or frequently visited. This is the fourth volume of the contributions to be devoted to a state flora, the others being the Botany of Western Texas (volume 2), the Plant Life of Alabama (volume 6) and the Flora of Washington (volume I1).}, keywords = {field manual, flora, government publication, New Mexico, species}, url = {/files/bibliography/002.pdf}, author = {Wooton, E.O. and Standley, P. C.} } @mastersthesis {52653, title = {The Flora of the Mesilla Valley}, year = {1903}, month = {1903}, abstract = {The first and principal purpose of this article is a portrayal of the Mesilla Valley flora, and a portrayal of it as it is; not as I myself, anyone else, or any theory would have it, but as I have found it to exist and have sketched or noted it to the best of my ability. After having done this by relating carefully observed facts, with no view whatever of verifying any hypothesis, I purpose to offer a few thoughts in explanation of the several, and somewhat sharply marked life zones of this valley. }, keywords = {flora, Mesilla Valley, thesis}, url = {/files/bibliography/004.pdf}, author = {Metcalfe, O.B.} }