@proceedings {JRN55420, title = {WRF-Chem simulation of a Southwest United States dust-on-snow episode }, year = {2022}, month = {12- 9 to14- 2022}, address = {Chicago, IL}, abstract = {Every year in spring (March-May) a large amount of dust is mobilized across the southwest United States and transported to the mountains that make up the Upper Colorado River Basin. The dust degrades air quality and influences snow hydrology when deposited on mountain snowpack. During 8-17 April 2013, three strong dust events transported a large amount of dust from the southwest drylands to the San Juan Mountains in Colorado where it subsequently accelerated snow melt and runoff. Despite the relevance of these repeated southwest dryland to mountain dust-on-snow episodes to regional hydrology, simulating dust emission and transport to the mountain snowpack accurately remains a challenge. Accurate prediction of dust-on-snow episodes at the scales that impact snowmelt rates would support water resource management in the southwest where communities and agriculture face critical water shortages, compounded by a regional megadrought. In this study, we analyzed the 15-17 April 2013 dust-on-snow event. The objectives of our analysis were to examine: 1) the meteorological setup that organized the dust episode; and 2) the capability of the Weather Research and Forecasting model with Chemistry (WRF-Chem) to simulate the dust episode. To simulate dust emission, we incorporate a satellite albedo-based drag partition parameterization into the Air Force Weather Agency (AFWA) dust emission module to improve the representation of wind stress on the erodible surface. We used reanalysis datasets, satellite and surface observations, upper-air observations, and high-resolution WRF-Chem simulations with horizontal resolutions of 18 km down to 2 km. Our analysis revealed that the coupled effect of strong upper-level divergence accompanying anti-cyclonic Rossby wave breaking and a strong low-level pressure gradient set up between the Colorado Plateau and its upwind region favored strong low-level southwesterly winds capable of emitting dust from the source region. Additionally, our simulation suggests that WRF-Chem dust transport simulation with the albedo-based drag partition in the AFWA dust emission module may be a viable tool for resolving dynamic processes and simulating dust-on-snow episodes in the southwest US. }, keywords = {dust emission, dust-on-snow, episode, simulation, snowpack, Southwest United States, Upper Colorado River Basin, WRF-Chem}, author = {Saroj Dhital and Nicholas Webb and Michael L. Kaplan and Travis W. Nauman and Danielle Duni and Susan LeGrand and Theodore W. Letcher and S. McKenzie Skiles and Patrick Naple and Nathaniel W. Chaney and Jiaxuan Cai} } @conference {JRN55356, title = {A web interface for exploring and setting land management benchmarks}, booktitle = {Society for Range Management Annual Meeting 2022}, year = {2022}, month = {2022}, abstract = {Land managers make their decisions informed by ~the best available data. Data require interpretation in order to be applied to management decisions, however. One method for interpreting quantitative data is the application of quantitative benchmarks. Benchmarks are values or ranges of values for a given measured indicator of landscape function which can be used to classify the data into management categories such as {\textquotedblleft}meeting{\textquotedblright} and {\textquotedblleft}not meeting{\textquotedblright} objectives or {\textquotedblleft}unsuitable,{\textquotedblright} {\textquotedblleft}marginal,{\textquotedblright} and {\textquotedblleft}suitable{\textquotedblright} habitat. Importantly, benchmarks can be tied to covariates like soils, landforms, or ecological sites, which then enables the application of benchmarks as a layer of interpretation. This practice is already widespread with applications like the Sage-Grouse Habitat Assessment Framework which uses benchmarks tied to season of use to classify measured indicator values according to habitat suitability classes. However, most potential use cases for benchmarks start with the difficult determination of the benchmark values for each classification category. In order to empower land managers to set their benchmarks, we have created a web application, the Benchmark Exploration Tool. This tool allows users to upload their own monitoring data or download data from the Landscape Data Commons and visualize them as histograms. Users are able to set quantiles to plot in the generated figures in order to better intuit the distribution of their data. Users can also set and apply benchmarks, based on policy, local knowledge of ecosystem structure and function, or other sources. This allows users to see how different benchmark values might affect their interpretation of the data. All figures and tables produced by the tool can be downloaded for use in reports or other documentation. With this tool, land managers can better understand their data and establish data-driven benchmarks for their management efforts.}, author = {Nelson Stauffer and Alexander Laurance-Traynor and Sarah McCord} } @article {JRN55338, title = {Water requirements for oil palm grown on marginal lands: A simulation approach}, journal = {Agricultural Water Management}, volume = {260}, year = {2021}, month = {11/6/2021}, pages = {107292}, abstract = {Oil palm is one of the most rapidly growing tree crops in the tropics. It is long-lasting and high yielding, serving as an input for a number of profitable industries. The rapid expansion of oil palm has triggered environmental change. Historically, the focus has been on the impact of biodiversity loss. However, the water requirements of oil palm plantations, which traditionally depended on rainfall only, are also changing, partly because environmental concerns are directing oil palm expansion and cultivation into marginal areas. According to some estimates, these lands with cultivable marginal soils{\textemdash} having an acid pyrite layer in the soil profile{\textemdash} comprise about 7.5 million ha in Indonesia. Here, we employed the Agricultural Production Systems sIMulator (APSIM) to simulate the growth of oil palm on marginal lands within Indonesia over an eight year period. APSIM-Oil palm was used to estimate the irrigation water requirement at different stages of plant growth for actual weather and soil conditions. Traditionally, water footprint accounting of oil palm plantations at the field level considers one uniform value of evapotranspiration. Our analysis shows that considering a single value for the entire period of oil palm growth underestimates the water requirement at the field scale. Annual irrigation needs were found to range from 2543 mm to 3865 mm for the plantation ages examined (0-8 years). We approximate that 8800 m3 of blue water and 6200 m3 of green water is required per ton of fresh fruit bunch produced from the study plantation occupying marginal lands, where water requirements were largely governed by maintenance of a high water table. Similarly high volumes are likely to be required where oil palm is cultivated on pyritic soils. Thus, the irrigation water requirement can no longer be neglected as oil palm plantations continue to expand onto marginal soils.}, keywords = {APSIM-Oil palm simulation, expansion, Marginal lands, Oil palm, Water footprint}, doi = {10.1016/j.agwat.2021.107292}, url = {files/bibliography/21-050.pdf}, author = {Humayoun Akram and Delphis F. Levia and Jeffrey E. Herrick and Henny Lydiasari and Niels Sch{\"u}tze} } @conference {JRN55400, title = {Where management and climate variability matter most: An evaluation of metrics for monitoring agroecosystem production and phenology}, booktitle = {2021 Fall Meeting of the American Geophysical Union}, year = {2021}, month = {8/5/2021}, abstract = {Effective measurement of seasonal variations in the timing and amount of production are critical to managing spatially heterogeneous agroecosystems in a changing climate. Although many technologies for such measurements are available, their relationships to one another at a continental extent are unknown. Using data collected from across the Long-Term Agroecosystem Research (LTAR) and other networks, we investigated correlations among key metrics representing primary production, phenology, and carbon fluxes in 34 cropland, grazingland, and crop-grazing integrated systems across the continental U.S. Metrics we examined included gross primary productivity (GPP) estimated from eddy covariance (EC) towers and modelled from the Landsat satellite, Landsat NDVI, and vegetation greenness (Green Chromatic Coordinate, GCC) from tower-mounted PhenoCams for 2017 and 2018. We analyzed production dynamics estimated from three independent ground and remote platforms for 51 site-years of co-located time series. We found that when similar methods were applied across the four metrics, pairwise sensor comparisons revealed stronger correlation and lower root mean square error (RMSE) between end of season (EOS) dates (Pearson R ranged from 0.6 to 0.7 and RMSE from 32.5 to 67.8) than start of season (SOS) dates (0.46 to 0.69 and 40.4 to 66.2). Overall, moderate to high correlations between SOS and EOS metrics complemented one another except at some lower productivity grazingland sites where estimating SOS can be challenging and inter-annual variability in production is high. Growing season length estimates derived from 16-day Satellite GPP (179.1 days) were significantly longer than those from PhenoCam GCC (70.4 days, padj < 0.0001) and EC GPP (79.6 days, padj < 0.0001). Landscape heterogeneity did not explain differences in SOS and EOS estimates. Annual integrated estimates of productivity from EC GPP and PhenoCam GCC diverged from those estimated by Landsat GPP and NDVI at sites where annual production exceeds 1000 gC m-2 yr-1. We identified production systems where management and climate variability mattered most and offered ideas we feel can advance our capacity to better integrate management decision-making into long- and short-term forecasting for drought and climate scenarios at multiple spatial scales.}, author = {Dawn M. Browning and Eric S. Russell and Guillermo E. Ponce-Campos and N. E. Kaplan and Andrew D. Richardson and Bijan Seyednasrollah and S. Spiegal and Nicanor Z. Saliendra and Joseph G. Alfieri and J. M. Baker and Carl Bernacchi and Brandon T Bestelmeyer and David D. Bosch and Elizabeth H. Boughton and Raoul K. Boughton and Patrick E. Clark and Gerald N. Flerchinger and Nuria Gomez-Casanovas and Sarah Goslee and Nick Haddad and David L. Hoover and Marguerite Mauritz and Gretchen R. Miller and John Sadler and Amartya Saha and Russell L. Scott and Andrew Suyker and Craig Tweedie and Jeffrey D. Wood and Xukai Zhang and Shawn D. Taylor} } @article {JRN55286, title = {Weight gain, grazing behavior and carcass quality of desert grass-fed Rar{\'a}muri Criollo vs. crossbred steers}, journal = {Livestock Science}, volume = {249}, year = {2021}, month = {10 April 2021}, abstract = {Rar{\'a}muri Criollo cattle producers often crossbreed their cows with improved beef-breed bulls and/or retain and develop their yearlings on rangeland because of limited weaned calf markets, however it is unknown if Rar{\'a}muri Criollo steers exhibit marketable weight gains and carcass qualities, or desirable grazing behaviors documented in cows of this biotype. We evaluated two cohorts (cohort: 1 = 31, 2 = 26) of Rar{\'a}muri Criollo (JRC), Mexican Criollo (MC) and Criollo {\texttimes} beef-breed crossbred (XC) steers to investigate effects of biotype on growth, carcass traits, and landscape utilization. Steers were weighed approximately once every 2-mo and average daily gains (ADG) calculated. Nine JRC and XC steers per cohort were monitored at 5-min intervals via global positioning systems (GPS) for 1-mo during winter (2015{\textendash}16) and late-summer (2016{\textendash}17). Weight and carcass data were analyzed using mixed measures procedures to identify differences between biotype through time. Discriminant analyses were conducted to determine whether grazing behaviors could be discriminated among: 1) JRC and XC steers and JRC cows; 2) steers by season (winter vs. summer); and 3) steers of cohort 1 and 2. Final live and carcass weights of XC were greater than JRC and MC, but all were market ready at 30-mo following a grass-finishing protocol. Carcass quality and ADG were not different among biotypes. Steers were discriminated into different season or cohort groups based on grazing behavior differences but JRC and XC steers exhibited grazing patterns that were similar to those previously observed in JRC cows. Our results suggest that JRC, MC, and XC steers can be developed to slaughter weights in 30-mo using a rangeland-based grass-fed protocol, and that JRC and XC steers exhibit desirable grazing behaviors previously observed in JRC cows.}, keywords = {beef cattle, climate change, Grass finished steers, Grass-fed supply-chain, Heritage genetics, livestock behavior}, issn = {1871-1413}, doi = {10.1016/j.livsci.2021.104511}, url = {files/bibliography/21-020.pdf}, author = {Matthew M. McIntosh and Andr{\'e}s F. Cibils and Richard E. Estell and S. Nyamuryekung{\textquoteright}e and Amy L. Gonzalez and Qixu Gong and Huiping Cao and S. Spiegal and S. Soto-Navarro and Amanda D.Blair} } @article {JRN55348, title = {Wind erosion response to past and future agro-pastoral trajectories in the Sahel (Niger)}, journal = {Landscape Ecology}, year = {2021}, month = {11/09/2021}, abstract = {Context Wind erosion plays a major role in land degradation in semi-arid areas, especially in the Sahel. There, wind erosion is as sensitive to land use and land management as to climate factors. Future land use intensification may increase wind erosion and induce regional land degradation. Objective We aimed to estimate wind erosion responses to changing land management in a Sahelian region. Methods We defined land use intensification scenarios for a study site in southwestern Niger for two historical situations (1950s and 1990s), and two alternative prospective scenarios (2030s: extensive or intensive). We simulated vegetation growth and horizontal sediment flux of wind erosion for the corresponding landscapes. Results Annual amounts of horizontal sediment flux increased with land management changes from 1950s (nil flux) to 1990s (176 kg m-1 yr-1) and 2030s (452 to 520 kg m-1 yr-1), mostly because of differences in land use, declining soil fertility, and practices decreasing the dry vegetation. For 2030s, intensive scenario exhibited larger vegetation yields than extensive conditions, but similar large values of horizontal sediment flux, thus questioning the sustainability of both scenarios. Realistic sets of practices had as large an influence as the largest theoretical range of practices on the variability of annual horizontal sediment flux. This variability was as large as that due to meteorological conditions. Conclusions This study demonstrates that the environmental impact of land use and management practices, of which wind erosion is an aspect, must be assessed at the landscape scale to account for the variability in land cover and associated land management.}, keywords = {Agro-pastoral practices, Land management scenarios, land use, modelling, Sahel, wind erosion}, doi = {10.1007/s10980-021-01359-8}, url = {files/bibliography/21-057.pdf}, author = {C. Pierre and P. Hiernaux and Jean-Louis Rajot and L. Kergoat and Nicholas Webb and A. Abdourhamane Tour{\'e} and B{\'e}atrice Marticorena and C. Bouet} } @article {JRN55288, title = {Water footprint of rangeland beef production in New Mexico}, journal = {Water}, volume = {13}, year = {2021}, month = {7/15/2021}, pages = {1950}, abstract = {New Mexico (NM) has been identified as the state in the US that will be most adversely impacted by climate change and associated water stress. Roughly 92\% of NM is rangeland, most of which is grazed by beef cattle. We calculated the blue (surface and ground) and green (precipitation) water footprints (WF) of NM beef cattle industry (cow-calf, backgrounding, and feedlot). This analysis indicated that the weighted average WF of NM beef cattle was 28,203 L/kg meat. The majority of the WF was accounted for green water (82\%; 23,063 L/kg meat) used by rangeland forages. Blue water accounted for only 18\% (5140 L/kg meat) of the total beef WF estimate. The relative contribution of green vs. blue water varied significantly among the different phases of beef production. In cow-calf, green water accounted for 99.5\% of the WF whereas blue water, accounted for 100\% of beef WF during backgrounding and feedlot. Based on our estimate, NM cow-calf operations is about a third or a quarter of the blue water (m3/year) used to produce corn or wheat, and only 5\% or less of the water used to produce cotton or hay. In NM, irrigation accounts for about 84\% of freshwater use followed by public/domestic use of 10\%. Mining, thermo-electric, livestock production, aquaculture, and industrial uses collectively account for the other 6\%.}, keywords = {blue water; green water; drought; forage crops; climate change; New Mexico}, doi = {10.3390/w13141950}, url = {files/bibliography/21-023.pdf}, author = {Mohammed N. Sawalhah and Hatim M. E. Geli and Jerry L. Holechek and Andr{\'e}s F. Cibils and S. Spiegal and Craig Gifford} } @conference {JRN55401, title = {What would it take to detect land surface phenology in sparsely vegetated drylands?}, booktitle = {Ecological Society of American Conference 2021}, year = {2021}, month = {3/3/2021}, abstract = {Land surface phenology (LSP) enables ecosystem scale tracking of the drivers and consequences of a changing climate, but it{\textquoteright}s useability is limited in some areas. In dryland ecosystems low vegetation cover is the primary limitation in LSP detection. Low vegetation cover can cause the growing season vegetation index (VI) to be indistinguishable from the dormant season VI, making phenology extraction impossible. Here, using both simulated data and multi-temporal drone imagery of a desert shrubland, we explore the feasibility of detecting LSP with respect to fractional vegetation cover, plant functional types, and sensor observation error. We found that plants with distinct VI signals, such as deciduous shrubs with a high leaf area index, require at least 30-40\% fractional cover on the landscape to consistently detect pixel level phenology. Evergreen plants, which have lower VI amplitude between dormant and growing seasons, require considerably higher cover and can sometimes have undetectable phenology even with 100\% fractional cover. We also found that even with adequate cover, biases in phenological metrics can still be up to 20 days, and can never be 100\% accurate due to observation error from shadows, viewing angle, and atmospheric interference. Our work also highlights some understudied limitations in drylands LSP. For example some areas may have the occasional season which meets a minimum VI threshold for detecting phenology, potentially indicating a higher than normal productive year. Our results show that these years may happen solely due to chance as opposed to increased productivity.~ The ability to detect phenology in drylands with current satellite sensors is severely limited in many areas with low vegetation cover, such as the Sonoran and Mojave desert regions, as well as areas with large amounts of evergreen vegetation, such as sagebrush ecosystems in the Wyoming and Columbia basins. Along with recent studies our work suggests that the timing and amplitude of peak productivity is the best way to study dryland LSP with current satellite based sensors. Future sensor technologies with sub-meter resolution will allow for identification of individual plants and are the best path forward for studying large scale phenological trends in drylands. }, author = {Shawn D. Taylor and Dawn M. Browning and Ruben Baca} } @article {JRN55211, title = {Woody Plant Encroachment has a Larger Impact than Climate Change on Dryland Water Budgets}, journal = {Scientific Reports}, volume = {10}, year = {2020}, month = {05/2020}, abstract = {Woody plant encroachment (WPE) into grasslands is a global phenomenon that is associated with land degradation via xerifcation, which replaces grasses with shrubs and bare soil patches. It remains uncertain how the global processes of WPE and climate change may combine to impact water availability for ecosystems. Using a process-based model constrained by watershed observations, our results suggest that both xerifcation and climate change augment groundwater recharge by increasing channel transmission losses at the expense of plant available water. Conversion from grasslands to shrublands without creating additional bare soil, however, reduces transmission losses. Model simulations considering both WPE and climate change are used to assess their relative roles in a late 21st century condition. Results indicate that changes in focused channel recharge are determined primarily by the WPE pathway. As a result, WPE should be given consideration when assessing the vulnerability of groundwater aquifers to climate change.}, doi = {doi.org/10.1038/s41598-020-65094-x}, url = {files/bibliography/20-018.pdf}, author = {A. P. Schreiner-McGraw and Enrique Vivoni and Ajami, Hoori and O. E. Sala and Heather L. Throop and Debra C. Peters} } @conference {JRN55059, title = {Wind erosion as a footprint of evolving Sahelian agro-pastoral systems: A case study in southwestern Niger}, booktitle = {European Geoscience Union General Assembly}, year = {2019}, month = {04/2019}, address = {Vienna, Austria}, abstract = {

Wind erosion is a key land degradation process that impacts agricultural sustainability in drylands like the Sahel. In such populated areas, agro-pastoral activities significantly affect soil susceptibility to wind erosion, especially through modification of protective vegetation cover. Over the last decades, Sahelian demographic growth induced a large cropland expansion along with changes in agrarian practices. At the same time, climate variability has been very large in the Sahel, with severe droughts and large fluctuations in annual rainfall, impacting crop production and ground cover. The dual stressors of demographic growth and highly variable rainfall potentially increased wind erosion and accelerated its feedbacks on agricultural production. This work investigates wind erosion responses to scenarios of change in agro-pastoral practices for a Sahelian study site in southwestern Niger. We use an ecological state change framework to provide context for assessing impacts of land use and management changes on aeolian sediment transport rates. Relying on local measurements of meteorological data and on simulations of vegetation cover and wind erosion, agro-pastoral practices are modelled for ecological sites (plant-soil complexes) typical of the area. The practices, derived from literature review and from expert knowledge, account for fallow shortening, decreasing soil fertility, change in cultivars, manuring, and crop residue management, that are typical in southwestern Niger. The simulated wind erosion fluxes are analyzed as integrated footprints of evolving agro-pastoral activities under a fast-growing demographic pressure and a large climate variability. These results provide a basis for investigating impacts of future land use, land cover and land management change on wind erosion in the Sahel.

}, author = {C. Pierre and Nicholas Webb and Jean-Louis Rajot and L. Kergoat and Amadou Abdourhamane} } @conference {JRN55241, title = {A web interface for creating random, spatially balanced landscape monitoring designs}, booktitle = {Society for Range Management}, year = {2019}, month = {02/2020}, address = {Denver, Colorado}, abstract = {In the monitoring and assessment of landscapes, randomly located sampling plots are often used to minimize sampling bias and enable inference to larger landscape units. In particular, spatially balanced random designs are more robust to spatial autocorrelation and therefore produce data usable for answering multiple management questions. The Generalized Random Tessellation Stratified (GRTS) approach is one technique for creating spatially balanced random designs in natural resources and has been widely adopted by multi-scale terrestrial and aquatic monitoring programs. While the parameters for a GRTS design are relatively simple to specify with stratification polygons and per-stratum sample sizes, generating a design from those inputs has historically required the ability to code using the R package spsurvey. As a result, technical skills have been a bottleneck for this statistical approach in resource monitoring programs. To remove this technological barrier, we have developed a web application, the {\textquotedblleft}Balanced Design Tool{\textquotedblright}, to create GRTS designs through a graphical interface. The tool prompts users to upload polygons describing their study area and stratification then to specify the number of points to draw per stratum before generating a spatially balanced design. Version 1.5, released in October 2019, added significant functionality. The point allocation process now supports three different approaches (manual, proportional by stratum area, and equally by stratum) through a more user-friendly interface. Users can now use an interactive, webmap to evaluate their designs without needing mapping software (e.g. ArcGIS). The final downloaded design now includes all the files (including an R script) to recreate the design and design documentation. With this tool, land managers can now create their own reproducible, spatially balanced designs to develop locally appropriate, statistically valid monitoring programs to suit a wide variety of objectives. Poster Pod 43, $\#$92.}, author = {Nelson Stauffer and Sarah McCord and Jason W. Karl} } @conference {JRN55252, title = {What makes southwestern communities resilient to climate change?}, booktitle = {American Geophysical Union}, year = {2019}, month = {12/2019}, address = {San Francisco, California}, abstract = {With multiple interpretations of resilience in the physical and social science literature, and little consensus on its measurement and evaluation, determining what makes communities resilient to climate change can be challenging. Our goal is to identify drivers of community resilience in the southwest United States to inform outreach needs. These drivers may be physical traits of the community infrastructure and the surrounding environment, socio-economic and demographic characteristics of the community itself, or actions taken by public or private entities, individuals or groups to build community resilience. In pursuit of this goal, we have stepped outside of the conventional literature review to inventory programs that aim to improve community climate change readiness. In doing so, we establish how practitioners see resilience and consider climate change not in isolation but as a problem that co-exists with multiple issues such as available energy, transport, employment, housing, health services, access to food etc. We highlight challenges specific to the southwest region, where water is scarce, population is concentrated in urban and exurban settlements, and agriculture is important both economically and culturally. Further, the southwest sees some of the highest levels of poverty and deprivation in the country, most notably in tribal communities which have long been subject to institutional inequities and discrimination. Economically-disadvantaged communities will be disproportionately impacted by climate change and this is an environmental justice issue. To conclude, we summarize the infrastructural, demographic and socio-economic characteristics of resilient communities and we identify priority actions for outreach to build greater resilience for vulnerable southwestern communities. Poster $\#$624120.}, author = {Caitriana Steele and Gutierrez, Paaul and Skye Aney and Emile H. Elias and J.T. Reyes and Helena Deswood} } @proceedings {JRN54869, title = {Weight gain and behavior of Raramuri Criollo versus Corriente steers developed on Chihuahuan Desert rangeland}, volume = {January 28-February 2, 2018}, year = {2018}, month = {01/28/2018}, publisher = {Society for Range Management Meeting Proceedings}, address = {Sparks, Nevada}, abstract = {

Ranchers that raise Criollo cattle must overcome the challenge of lack of markets for weaned calves. Raramuri Criollo (RC) steers are commonly raised for beef and finished on rangelands, while Corriente (CR) are often raised for rodeo sports. No data exist on weight gains and grazing behavior of rangeland-raised steers of either biotype. We conducted a study in the Chihuahuan Desert with two cohorts of RC and CR. Twenty-two 17-month (cohort 1) steers (10 RC, RC1; 12 CR, CR1) were weighed every 60 d between December 2015 and January 2017 and eighteen 8-month (cohort 2) steers (7 RC, RC2 and 11 CR, CR2) were weighed every 60 d between December 2015 and August 2017 to determine individual body weight (WT), average daily gain (ADG), and body condition score (BCS). 9 cohort 1 steers and 9 cohort 2 steers were monitored with Lotek 3300LR GPS collars that recorded location at 5 min intervals during December 2015 and December 2016, respectively, to compare landscape utilization patterns of 5 RC and 4 CR individuals. The influence of biotype on WT, ADG, BCS and behavior variables was analyzed using repeated measures mixed ANOVA that treated steers as the experimental unit. Separate analyses were conducted per age cohort. No differences in WT, ADG, or BCS between RC and CR in either cohort were detected throughout. RC1, CR1, RC2, and CR2 gained on average 0.2036, 0.1420, 0.1881, and 0.2419 kg/head/d, respectively. Daily distance traveled by RC1 and CR1 did not differ, but CR2 walked farther during day and night than RC2 (P \<0.01). CR1 followed more sinuous trajectories than RC1 counterparts from dusk to midnight (P\<0.01). CR2 followed more sinuous movement trajectories than RC2 at night (P\<0.01). \ Further research is needed to determine the benefits of developing RC vs CR steers on desert rangeland.

}, author = {Matthew M. McIntosh and Andr{\'e}s F. Cibils and Richard E. Estell and S. Soto-Navarro and Amy L. Gonzalez and S. Nyamuryekung{\textquoteright}e and S. Spiegal} } @conference {JRN54798, title = {Watching grass grow: Successes and limitations of image-based methods for monitoring grassland phenology}, booktitle = {12th International Congress of Ecology INTECOL 2017}, year = {2017}, month = {08/2017}, publisher = {International Congress of Ecology INTECOL }, organization = {International Congress of Ecology INTECOL }, address = {Beijing, China}, abstract = {

Seasonal changes in aboveground primary production (i.e. phenology) are influenced by environmental conditions with implications for land-atmosphere interactions, carbon cycling, and agricultural production. Monitoring phenology and quantifying seasonal patterns across spatially extensive grasslands and savannas require cost-effective, consistent, and accurate approaches for detecting changes in the growing season. Remotely sensed imagery offers capabilities to quantify growing season metrics via vegetation indices that have been linked to biomass and forage and net primary production. However, in many water-limited ecosystems contributions of exposed soil due to modest vegetation cover and susceptibility of vegetation to drought challenge these biophysical retrievals using moderate- and coarse-resolution satellite imagery. This challenge emphasizes the importance of verifying seasonal metrics derived from remotely sensed imagery (e.g., start, end, and length of growing season and timing of peak greenness) to identify limitations and uncertainty of said metrics used to forecast plant responses to climate and estimate biomass accrual and crop yields. We collected and evaluated data at multiple spatial and temporal scales from 2012 through 2016 to quantify the degree of correspondence between field and remotely sensed growing season metrics. This study was conducted at an ungrazed desert grassland site in southern New Mexico. Weekly field observations of plant phenology and canopy greenness were compared with metrics derived from MODIS satellite imagery and near-surface digital cameras (hereafter {\textquotedblleft}phenocams{\textquotedblright}). MODIS 250-m NDVI vegetation index data are acquired every 16 days while color images are acquired daily from phenocams mounted at a height of ca 6 meters providing data at finer spatial and temporal scales that those from satellite. In addition, phenocams offer the opportunity to identify individual plants in the image to extract species-specific patterns in greenness. Growing season metrics from both types of imagery were derived using Timesat software (v3.2).
Phenocam greenness curves for individual species indicated rapid canopy development for the widespread deciduous mesquite shrub (Prosopis glandulosa) over 14 to 16 d in the spring (April to May) whereas peaks in greenness for the dominant perennial black grama grass (Bouteloua eriopoda) occur with warm season rainfall in July. Weekly field estimates of canopy development were significantly correlated with greenness index values from phenocams for mesquite (r = 0.735) and black grama (r = 0.609). Start and end dates for growing season derived from MODIS NDVI corresponded well with phenocam greenness representing the landscape (R2 = 0.691) with better fit for end of season. These data demonstrate the utility of phenocams for reliably depicting species-specific patterns in phenology in this arid grassland although uncertainty with start of season for black grama was less than that for mesquite. The ability to distinguish contributions to landscape greenness between C3 shrubs and C4 grasses can dramatically enhance landscape monitoring efforts over spatially extensive grasslands and savannas where field monitoring is not feasible large areas. Future research will include additional grassland sites using image data from the Phenocam Network and online analytical tools that are in development to bolster opportunities to bridge satellite, camera, and field data to quantify and predict ecosystem productivity.

}, author = {Dawn M. Browning} } @conference {JRN54670, title = {Weight gain and behavior of Raramuri Criollo versus crossbred steers developed on Chihuahuan Desert rangeland}, booktitle = {70th Annual Society for Range Management Meeting}, volume = {Jan. 29 - Feb. 2, 2017}, year = {2017}, month = {01/2017}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Saint George, Utah}, abstract = {

Ranchers that raise Raramuri Criollo (RC) cattle must overcome the challenge of lack of markets for weaned calves. \ Growing and finishing RC or RC-crossbred steers on rangeland pastures is increasingly common; however, no data exist on their weight gains or grazing behavior. \ We tracked the weight and behavior of four groups of steers in the Chihuahuan Desert to understand the viability of this production approach. Nineteen 8-month steers (eleven RC, RC-8, and eight Brangus{\texttimes}Criollo, BRCR-8) and nineteen 17-month steers (ten RC, RC-17; nine Waguli{\texttimes}Criollo, WACR-17) were weighed every 60 days between 12/2015 and 10/2016 to determine individual body weight (WT), average daily gain (ADG), and body condition score (BCS). In addition, we used Lotek 3300 GPS collars to monitor location (at 5-minute intervals) of five RC-17 and five WACR-17 individuals in 12/2015. \ Influence of breed on WT, ADG, BCS and behavior was analyzed using repeated measures mixed ANOVA treating steers as experimental units. Separate comparisons were conducted within each age group. \ Crossbreds were heavier than their RC counterparts at the beginning of the study and WT differences in both groups persisted throughout (P\<0.01). \ ADG of RC-17 and WACR-17 were not detectably different, however BRCR-8 steers showed higher ADG than their RC-8 counterparts (P \< 0.014). BCS of crossbreds was significantly higher than that of RC steers in both age groups throughout (P\< 0.01). \ Overall, RC-8, BRCR-8, RC-17, and WACR-17 gained on average 158, 203, 166, and 156 lb head-1 11 months-1, respectively. \ Daily distance traveled by WACR-17 and RC-17 did not differ, however WACR-17 walked farther during nighttime hours (P \<0.01) and followed less sinuous movement trajectories (P\<0.01) than their RC-17 counterparts. Although WT gains at a younger age were improved by crossbreeding RC with Brangus, further research is needed to determine performance of older BRCR and younger WACR crossbreeds.

}, author = {Matthew M. McIntosh and Andr{\'e}s F. Cibils and Richard E. Estell and S. Soto-Navarro and Amy L. Gonzalez and S. Nyamuryekung{\textquoteright}e and S. Spiegal} } @article {JRN54801, title = {What the novel ecosystem concept provides: A reply to Kattan et al.}, journal = {Restoration Ecology}, volume = {25}, year = {2017}, month = {07/2017}, pages = {488-490}, chapter = {488}, abstract = {

The novel ecosystem concept expands the restoration palette by focusing our attention on what is possible when recovery to an historical pre-disturbance condition is not. Although some elements of the concept have long been accepted in restoration circles, the novel ecosystems framework brings these elements to the fore. There is a growing frustration with restoration prescriptions that above all else emphasize native species and historical trajectories, and there is a clear need for alternatives that recognize real limitations to achieving these goals in at least some instances. Though not perfect, the novel ecosystems framework represents such an alternative.

}, doi = {10.1111/rec.12530}, url = {files/bibliography/17-021.pdf}, author = {J.R. Miller and Brandon T Bestelmeyer} } @conference {JRN54445, title = {Weighing the costs of different errors when determining statistical significant during monitoring}, booktitle = {68th Annual Society for Range Management Meeting}, year = {2015}, month = {02/2015}, publisher = {Sociiety for Range Management}, organization = {Sociiety for Range Management}, address = {Sacramento, CA}, abstract = {

Selecting appropriate significance levels when constructing confidence intervals and performing statistical analyses with rangeland monitoring data is not a straightforward process. This process is burdened by the conventional selection of {\textquotedblleft}95\% confidence{\textquotedblright} (i.e., Type I error rate, a =0.05) as the default with no consideration as to whether, or in what circumstances, it is appropriate. The value of a =0.05 has its origins in hypothesis testing for scientific research where variation is controllable and the costs of making different errors are farily easily quantifiable. A core belief in scientific research is that the cost of committing a Type I error is much higher than committing a Type II error {\textendash} i.e., it is better to miss an experimental effect than to erroneously conclude that effect occurred. Yet, when managing rangeland resources, the costs of committing Type I and Type II errors are not the same as in research {\textendash} and often vary with objective and scale. In many rangeland resource applications making a Type II error (i.e., failing to detect a change) may actually be catastrophic {\textendash} e.g., failing to detect increases in bare ground cover may lead to continued overgrazing, soil loss and permanently decreased range health. Accordingly, for rangeland monitoring the selection of appropriate error rates should be based on: 1) the relative costs of making the two types of errors associated with statistical tests, and 2) the role the data analysis is to play in making management decisions and committing resources. We present a tiered framework for selecting appropriate error rates for rangeland monitoring designed to be sensitive to detecting change at its broadest level but have high specificity at finer levels depending on the costs of making errors at each of those levels. This approach enables statistical analyses that support proactive rather than reactive decision-making for natural resource management.

}, author = {Jason W. Karl and Unnasch, Robert S.} } @conference {JRN54497, title = {winderosionnetwork.org {\textendash} Portal to the National Wind Erosion Research Network}, booktitle = {AGU Fall Meeting}, year = {2015}, month = {12/2015}, publisher = {American Geophysical Union}, organization = {American Geophysical Union}, address = {San Francisco, CA}, abstract = {

The National Wind Erosion Research Network was established in 2014 as a collaborative effort led by the USDA Agricultural Research Service and Natural Resources Conservation Service, and USDI Bureau of Land Management, to address the need for standardized measurements of wind erosion and its controlling factors. Data will be used to support model development and identification of improved land management strategies that have global applications. By applying standard methods, the Network will overcome the common challenge of synthesizing independent studies to assess local-to-national scale wind erosion and dust emission. Twelve intensively instrumented Network sites will be operational by spring 2016, providing high-resolution measurements of aeolian sediment transport rates, meteorological conditions and soil and vegetation properties. These initial sites are located across rangelands and croplands in New Mexico, Texas, Arizona, California, Nevada, Colorado, Utah, North Dakota, Idaho and Washington. A primary objective of the Network is to facilitate collaboration among Network sites and the wider research community to address basic research questions about aeolian processes, model development, and evaluate practical management options. In support of Network activities, winderosionnetwork.org was developed to serve as a Network data portal, and provide online information about the National Wind Erosion Research Network including protocols and results. The website provides a comprehensive resource for scientists and managers interested in engaging with the Network and accessing Network products. The Network provides exciting opportunities to engage in a national long-term wind erosion research program that promises significant impact for our understanding and ability to predict and evaluate aeolian processes across land cover types and land use systems.

}, author = {Nicholas Webb and Jeffrey E. Herrick and Clingan, Scott and Brad Cooper and Ericha Courtright and Valerie LaPlante and Justin Van Zee} } @article {JRN53909, title = {Wind speed and sediment transport recovery in the lee of a vegetated and denuded nebkha within a nebkha dune field}, journal = {Aeolian Research}, volume = {12}, year = {2014}, pages = {135-141}, abstract = {

Field observations of scaled wind speed and sand transport recovery in the lee of a nebka within a field of nebkhas and then subsequently for the nebkha denuded of its vegetation cover were collected. The measurements of wind speed at 0.4 times the element height indicate that for both conditions wind speed recovery in the lee is exponential. The porous vegetation cover influences the rate of this recovery being more gradual for the vegetated form. The return to equilibrium wind speed occurs in both cases at approximately eight element heights. For either case the recovery of shear stress and the return to a constant value occurs much closer to the bluff body form than has been described for porous fences. The recovery of sand transport in the lee appears to be more rapid for the un-vegetated condition, which corresponds to the observed faster rate of wind speed increase. The observations did not show a continual increase in saltation flux with increasing downwind distance due to the increasing shear stress downwind and the increase that may be expected due to the fetch effect. The change in saltation flux with downwind distance was controlled by the sediment supply, which diminished with downwind distance. The interaction of a changing shear stress and the zone of influence created by the wind as it interacts with the roughness dimensions, along with the distribution of sediment available for transport bring increased complexity to modeling sand flux for this type of environment over different temporal scales. \© 2014 Elsevier B.V. All rights reserved.

}, keywords = {aeolian, nebkha, recovery of wind, sediment transport, transport in obstacle lee}, author = {J. Gillies and Nield, Joanna M. and William Nickling} } @article {49847, title = {Within-plant distribution of volatile compounds on the leaf surface of Flourensia cernua}, journal = {Biochemical Systematics and Ecology}, volume = {48}, year = {2013}, month = {01/2013}, pages = {144-150}, chapter = {144}, abstract = {

We are using Flourensia cernua as a shrub model to study the role of terpenes on intake by livestock. Two experiments were conducted to examine distribution of volatile chemicals within a plant in an effort to minimize sample variability. In Exp. 1, leaves (current year\&$\#$39;s growth) were collected from 20 tarbush plants. Two leaders were sampled from each of three positions (outer canopy, subcanopy, and basal) in all four quadrants (based on ordinal direction). In Exp. 2, 10 leaders of current year\&$\#$39;s growth were removed from another 20 plants. Leaders were collected from the outer canopy of each quadrant and separated into thirds before removing leaves, thereby creating three leaf age categories. Volatile compounds were extracted with ethanol and analyzed with gas chromatography/mass spectrometry. Ninety-four chemicals (including 15 unknowns) were present on the leaf surface of F. cernua. Although 14 and 21 compounds differed (P \< 0.05) among quadrants in Exp. 1 and 2, respectively, no consistent quadrant effect was detected in either study. Leaf position differed (P \< 0.05) for 52 chemicals in Exp. 1 but outer canopy and subcanopy leaves differed for only 10 compounds. In Exp. 2, 63 compounds differed among leaf age categories. Immature leaves contained greater concentrations of 46 chemicals (P \< 0.05) than moderate or mature age categories, but moderate and mature leaves differed for only seven compounds. Estimated total concentration (i.e., cumulative concentration of all compounds) was not affected by leaf position but varied among leaf age categories (P \< 0.05; immature \> moderate \> mature). Differences in leaf position were attributed about equally to mono- and sesquiterpenes, whereas leaf age was affected to a greater extent by sesquiterpenes. Leaf position and maturity both affect terpene concentration and sampling variability for tarbush. However, little difference was detected between subcanopy and canopy positions. Thus, by avoiding basal sprouts and sampling from the mid-point of current year\&$\#$39;s growth, sampling variation should be minimal.

}, keywords = {Flourensia cernua, leaf age, plant secondary metabolites, terpenes, volatiles, within-plant distribution}, doi = {10.1016/j.bse.2012.11.020}, url = {/files/bibliography/13-002.pdf}, author = {Richard E. Estell and D. K. James and E.L. Fredrickson and D.M. Anderson} } @article {49861, title = {Water controls on nitrogen transformations and stocks in an arid ecosystem}, journal = {Ecosphere}, volume = {4}, year = {2013}, pages = {Article 11}, abstract = {

Following water, nitrogen (N) is the most frequent limiting factor to aboveground net primary production in arid ecosystems. Increased water availability can stimulate both plant nitrogen uptake and microbial nitrogen mineralization, but may also stimulate losses from the ecosystem. Here, we assess the effect of water availability on nitrogen stocks and transformations in an arid ecosystem. We conducted a field experiment with five levels of precipitation input (-80\%, -50\%, ambient, +50\%, +80\%) and two levels of N fertilization (ambient or 10 gm-2yr-1 NH4NO3) in a desert grassland of the Chihuahuan Desert. We measured in situ net N mineralization, plant N uptake, foliar N, N leaching under grass-rooting zone, and soil N availability during two years. Our results showed that increased water availability did not affect net N mineralization, but there was higher plant N uptake than with drought. Soil inorganic N pools were 2{\textendash}4 times lower with increased water availability compared to drought conditions. N leaching below grass-rooting zone was higher in dry than wet conditions because of higher available N. Increased water availability differentially affected N species significantly reducing the NO3:NH4 ratio. The accumulation of inorganic N during drought was the result of a decoupling between microbial and plant activity, and suggests that the cycling of N is more open in dry years than in wet years.

}, keywords = {arid ecosystems, Chihuahuan Desert, net N mineralization, nitrogen leaching, nitrogen-water interactions, soil inorganic N}, doi = {10.1890/ES12-00263.1}, url = {/files/bibliography/13-003.pdf}, author = {Lara Reichmann and O. E. Sala and Debra C. Peters} } @article {49908, title = {When bulk density methods matter: implications for estimating soil organic carbon pools in coarse soils}, journal = {Journal of Arid Environments}, volume = {77}, year = {2012}, month = {02/2012}, pages = {66-71}, chapter = {66}, abstract = {

Resolving uncertainty in the carbon cycle is paramount to refining climate predictions. Soil organic carbon (SOC) is a major component of terrestrial C pools, and accuracy of SOC estimates are only as good as the measurements and assumptions used to obtain them. Dryland soils account for a substantial portion of global SOC, but the pool dynamics are highly uncertain. One crucial component of accurate estimates of SOC on an areal basis is bulk density (ρb), the mass of soil per unit volume. Here, we review methods used for calculating ρb and assess their prevalence. We show how treatment of coarse fragments (particles \>2 mm diameter) influences ρb values and discuss the implications for SOC estimates in drylands. In four dryland examples, methods that varied in their treatment of coarse fragments led to substantial (up to 26\%) differences in ρb. Calculated SOC pools responded proportionally, with SOC differing by up to 518 g C m-2. We suggest a revised method for accounting for coarse fractions in ρb calculations. A large portion of the world{\textquoteright}s soils, particularly in drylands, are fine enough to allow ρb determination with cores, but contain coarse fragments that substantially impact SOC mass estimates if not explicitly considered.

}, keywords = {bulk density, carbon pool, SOC, soil organic carbon}, doi = {10.1016/j.jaridenv.2011.08.020}, url = {/files/bibliography/12-001.pdf}, author = {Heather L. Throop and Steven R. Archer and Curtis H. Monger and S. Waltman} } @article {49926, title = {Woody plant proliferation in North American drylands: a synthesis of impacts on ecosystem carbon balance}, journal = {Journal Geophysical Research - Biogeosciences}, volume = {116}, year = {2011}, month = {08/10/2011}, chapter = {G00K07}, abstract = {

Changes in the magnitude and direction of ecosystem carbon (C) balance accompanying woody plant encroachment are among the largest contributors to the uncertainty in the North American C budget. In this synthesis we identify the important species contributing to woody encroachment, summarize our current knowledge of aboveground and belowground C storage change with woody encroachment, and evaluate the range of human and natural disturbance factors that alter the course of C gains and losses within ecosystems experiencing woody encroachment. Available data indicate that relative to the historic vegetation, aboveground net primary production (ANPP) decreases with woody plant encroachment in arid regions (mean annual precipitation (MAP) \< 336 mm), but increases in semiarid and subhumid regions (on the order of 0.7 g C m-2 yr-1 per mm of MAP over 336 mm). Soil organic carbon response to woody plant encroachment ranged from losses of 6200 g C m-2 to gains of 2700 g C m-2 with an average accumulation of 385 g C m-2 across all studies and did not appear to be closely coupled to ANPP. Taken together, in the absence of disturbance, woody encroachment appears to result in a net ecosystem C gain across most species and ecoregions. However, disturbance associated with wildfire, land management practices, and drought may quickly and significantly offset these gains and should be explicitly factored into regional-scale C balance estimates. Our findings may be used to better constrain future estimates of woody plant encroachment influences on the North American C budget.

}, keywords = {aboveground net primary productivity, carbon cycle, ecosystem carbon balance, North America, soil organic carbon, woody encroachment}, doi = {10.1029/2010JG001506}, url = {files/bibliography/JRN00589.pdf}, author = {N. Barger and Steven R. Archer and J. L. Campbell and C. Huang and J. Morton and A. K. Knapp} } @article {49998, title = {When bulk density methods matter: Implications for estimating soil organic carbon pools in rocky soils}, journal = {Journal of Arid Environments}, volume = {77}, year = {2011}, pages = {66-71}, abstract = {Resolving uncertainty in the carbon cycle is paramount to refining climate predictions. Soil organic carbon (SOC) is a major component of terrestrial C pools, and accuracy of SOC estimates are only as good as the measurements and assumptions used to obtain them. Dryland soils account for a substantial portion of global SOC, but the pool dynamics are highly uncertain. One crucial component of accurate estimates of SOC on an areal basis is bulk density (pb), the mass of soil per unit volume. Here, we review methods used for calculating pb and assess their prevalence. We show how treatment of coarse fragments (particles \>2 mm diameter) influences pb values and discuss the implications for SOC estimates in drylands. In four dryland examples, methods that varied in their treatment of coarse fragments led to substantial (up to 26\%) differences in pb. Calculated SOC pools responded proportionally, with SOC differing by up to 518 g C m-2. We suggest a revised method for accounting for coarse fractions in pb calculations. A large portion of the world\’s soils, particularly in drylands, are fine enough to allow pb determination with cores, but contain coarse fragments that substantially impact SOC mass estimates if not explicitly considered.}, doi = {doi:10.1016/j.jaridenv.2011.08.020}, author = {Heather L. Throop and Steven R. Archer and Curtis H. Monger and S. Waltman} } @inbook {50101, title = {The western United States rangelands, a major resource}, booktitle = {Grassland, Quietness and Strength for a New American Agriculture}, year = {2009}, month = {June 2009}, chapter = {Chapter 5}, abstract = {Rangeland is a type of land found predominantly in arid and semiarid regions, and managed as a natural ecosystem supporting vegetation of grasses, grass-like plants, forbs, or shrubs. There are approximately 761 m ac of rangeland in the United States, about 31\% of the total land area. This land type is characterized by 4 features: 1) limited by water and nutrients, primarily nitrogen (N), 2) annual production is characterized by tremendous temporal and spatial variability, 3) a nested landscape of public and private ownership, and 4) throughout their history of use these lands have been uniquely coupled systems of both people and nature. In the U.S. Department of Agriculture{\textquoteright}s 1948 Yearbook of Agriculture, the chapter on rangelands focused on a description of these lands occurring by region across the western United States, and the principles, developed mostly in the early 20th century, to manage these lands to provide the provisioning services of food and fiber through livestock grazing. In the last 60 years, these western rangelands have undergone a transformation as the U.S. population has grown to over 300 million and relocated to urban areas within the western and southwestern states. This population dynamic, along with tremendous changes in agricultural production and a reduction in the population involved in agriculture have resulted in significant changes in the uses and emphases placed upon these western lands. This land type is now often looked to provide a multitude of goods and services not only to rural populations, but also to tens of millions of people in large urban areas located within these rangelands. In this chapter it is our intent to reflect on the extent and nature of this transformation over the last 60 years. We start with a description of this human dynamic, and its sociological implications. We describe the major regions of the western continental U.S., the focal point of U.S. rangelands.}, keywords = {natural, rangeland, resource, western U.S.}, url = {/files/bibliography/09-011.pdf}, author = {Kris Havstad and Debra C. Peters and Allen-Diaz, B. and Brandon T Bestelmeyer and D.D. Briske and Joel R. Brown and M. Brunson and Jeffrey E. Herrick and P. Johnson and L. A. Joyce and Pieper, Rex D. and Svejcar, A.J. and Jin Yao and James Bartolome and Lynn Huntsinger} } @proceedings {50136, title = {Water harvesting applictions for rangelands}, year = {2009}, month = {May 2-9, 2009}, address = {Ft. McDowell, AZ}, abstract = {Although water harvesting techniques have been used effectively in irrigated agriculture and domestic water supplies, there seems to have been little continued exploitation of the same techniques in arid and semiarid rangeland restoration. A review of the history of rangeland water harvesting allows identification of the methods that have been useful in the past and which would be likely effective in the future. It seems that relatively simple water harvesting approaches work best on rangelands, particularly water ponding dikes to stimulate vegetation growth, and possibly the use of larger-scale water spreaders. The complexity of larger scale applications, however, may lead to problems in operational use. Experience from rangeland water harvesting at the Jornada Experimental Range in the south central New Mexico and other locations in the Southwest indicates that the approach is a long-term solution that produces significant vegetation growth, generally 10-15 years after installation because of the sporadic and spatially distributed nature of the summer monsoon rainfall. Additionally, the use of water ponding dikes seems to most reliably produce an {\textquotedblleft}island{\textquotedblright} of enhanced soil moisture and increased habitat cover and forage. Water ponding dikes are easy and relatively inexpensive to construct and produce a pattern of vegetation similar to naturally occurring banded vegetation. Even very shallow dikes (7.5cm) are shown to produce ponds and a significant vegetation response. Research needs to be done to determine if the bands of vegetation behind the dikes will function like natural banded vegetation and expand to larger areas. Climate change continues to impact our water supplies, and the historical techniques of water harvesting that have been successfully used for over 9,000 years are a viable rangeland water conservation alternative now and in the future.}, keywords = {harvesting, rangeland restoration, water}, author = {A. Rango and Kris Havstad} } @article {50135, title = {Water-harvesting applications for rangelands revisited}, journal = {Environmental Practice}, volume = {11}, number = {2}, year = {2009}, month = {June 2009}, pages = {84-94}, abstract = {Although water harvesting techniques have been used effectively in irrigated agriculture and domestic water supplies, there seems to have been little exploitation of the same techniques in arid and semiarid rangeland restoration. A review of the history of rangeland water harvesting allows identification of the methods that have been useful in the past and which would be likely effective in the future. It seems that relatively simple water harvesting approaches work best on rangelands including water ponding dikes to stimulate vegetation growth, stock tanks for livestock watering, and possibly the use of larger-scale water spreaders, although their complexity sometimes can lead to problems in operational use. Rangeland water harvesting in the southwest U.S. indicates that the approach is a long-term solution that produces significant vegetation growth generally after 10-15 years because of the sporadic and spatially distributed nature of the summer monsoon rainfall. Additionally, the use of water ponding dikes seems to most reliably produce an island of increased soil moisture and increased forage. Water ponding dikes are easy and relatively inexpensive to construct and produce a pattern of vegetation similar to naturally occurring banded vegetation. Even very shallow dikes (7.5cm) produce ponds and a significant vegetation response. Research needs to be done to see if the bands of vegetation behind the dikes will function like banded vegetation and expand to larger areas. As climate change continues to impact our water supply, the techniques of water harvesting will become a viable rangeland water conservation alternative in the future.}, keywords = {harvesting, journal, water}, doi = {10.1017/S1466046609090140}, url = {/files/bibliography/09-017.pdf}, author = {A. Rango and Kris Havstad} } @conference {50147, title = {Weed management using goats: Effects on water infiltration rate}, booktitle = {Society for Range Management}, series = {62nd Society for Range Management Annual Meeting}, year = {2009}, month = {February 8-12, 2}, pages = {75-7}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Alb., NM}, abstract = {Goats are used increasingly for weed control, fire fuel reduction and ecological restoration. The high stocking rates typical of these applications have been reported to decrease the rate of water infiltration in goat pastures. The hypothesis that annual goat browsing for weed control decreases infiltration rate was tested in the Rio Grande River floodplain near Socorro, New Mexico (mean annual rainfall 200.9 {\textpm} 60.82 mm). Soils were coarse-loamy, mixed (calcareous), thermic Typic Torrifluvents with sandy loam surface texture. One plot (0.17-1.6 ha) from each of six pairs of plots was browsed at the end of the summer growing seasons. The 400-630 Boer/Spanish meat goats browsed the plots for 1-3 days at a mean stocking rate of 3.2{\textpm} 2.4 goat h m-2. Vegetation cover was measured using line point-intercept transects. Water infiltration rate was measured using a standardized saturated single-ring infiltration method. After four years of annual goat browsing and regrowth of vegetation, the rate of water infiltration was faster (P=0.036) in browsed areas (mean 1024 mm hr-1) than in unbrowsed areas (mean 896 mm hr-1). The increased cover of grasses and forbs, plus decreased cover of shrubs, increased mean infiltration rate in the browsed plots. Infiltration rate increased in unvegetated areas, probably due to disruption of the soil crust. The effects of goats on infiltration rate are probably influenced by climate, soil and vegetation characteristics, as well as season and stocking rate. The possible effects of goats on infiltration should be considered when designing weed management programs.}, keywords = {goats, management, SRM, water infiltration, weed}, author = {S. Tartowski and D. K. James} } @article {50180, title = {What can ant diversity-energy relationships tell us about land use and land change (Hymenoptera: Formicidae)?}, journal = {Myremecological News}, volume = {11}, year = {2008}, month = {June 28, 2008}, pages = {183-190}, abstract = {We identify and review an approach that views ant species diversity as a consequence of energy flux through an ecosystem. In this bottom-up view, energy apportioned to trophic guilds drives ant community responses to mesoscale variation generated by land-use and other processes. We introduce a conceptual model based upon this idea, and offer an interpretation of some data we have collected in the light of the model. Operationally, the concept focuses analysis upon the relationships between species richness/composition, trophic group identity, body size, and abundance. These attributes are compared among ecosystems that vary in total net primary productivity (NPP) and in how that productivity is divided among plant functional groups. We offer a brief example of how biomass and abundance of three ant trophic groups, large granivores, small granivores and scavengers, differed between two ecosystems that varied strongly in NPP patterns. We emphasize the value of linking ant measurements directly with NPP at mesoscales.}, keywords = {ant, diversity, energy flux, mesocale}, url = {/files/bibliography/08-031.pdf}, author = {Casanova, L.R. and Brandon T Bestelmeyer} } @article {50311, title = {Wind erodibility of soils at Fort Irwin, California (Mojave Desert), USA, before and after trampling disturbance: implications for land management}, journal = {Earth Surface Porcesses and Landforms}, volume = {32}, year = {2007}, note = {Originally submitted to Journal of Arid Environments, withdrawn for publication delay reasons. Submitted to Earth Surface Porcess and Landforms - published with different authors.Duplicate entries 183506-delete/159613-delete.}, month = {04/2007}, pages = {75-84}, publisher = {Wiley InterScience}, abstract = {We compared short-term effects of lug-soled-boot-trampling disturbance on water infiltration and soil erodibility on coarse-textured soils in the Mojave Desert. 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 also significantly reduced surface gravel cover. Trampling had similar effects at sites with both low and high chlorophyll a content, where chlorophyll a is used as an index of the level of microbiotic crust development. We concluded that trampling effects are relatively independent of the presence of microbiotic crusts in this environment. Instead, trampling appears to reduce infiltration by reducing gravel and coarse sand cover, facilitating the development of a sieving crust during rainfall simulation.}, url = {/files/bibliography/07-008.pdf}, author = {Jayne Belnap and Phillips, S.L. and Jeffrey E. Herrick and J. Johansen} } @article {50444, title = {Wind characteristics of mesquite streets in the northern Chihuahuan desert, New Mexico, USA}, journal = {Environmental Fluid Mechanics}, volume = {6}, year = {2006}, month = {June 1, 2006}, pages = {241-275}, abstract = {

Past research has shown that the most important areas for active sand movement in the northern part of the Chihuahuan Desert are mesquite-dominated desert ecosystems possessing sandy soil texture. The most active sand movement in the mesquite-dominated ecosystems has been shown to take place on elongated bare soil patches referred to as {\textquotedblleft}streets{\textquotedblright}. Aerodynamic properties of mesquite streets eroded by wind should be included in explaining how mesquite streets are more emissive sand sources than surrounding desert land. To understand the effects of wind properties, we measured them at two {\textquoteright}at mesquite sites having highly similar soil textures but very different con{\textquoteright}gurations of mesquite. The differences in wind properties at the two sites were caused by differences of size, orientation, and porosity of the mesquite, along with the presence of mesquite coppice dunes (sand dunes stabilized by mesquites growing in the dune and on its surface) found only at one of the two sites. Wind direction, u{\textquoteright} (friction velocity), z0 (aerodynamic roughness height) and D (zero plane displacement height) were estimated for 15-m tower and 3-m mast data. These aerodynamic data allowed us to distinguish {\textquoteright}ve categories with differing potentials for sediment transport. Sediment transport for the {\textquoteright}ve categories varied from unrestricted, free transport to virtually no transport caused by vegetation protection from wind forces. In addition, {\textquotedblleft}steering{\textquotedblright} of winds below the level of the tops of mesquite bushes and coppice dunes allowed longer parallel wind durations and increased wind erosion for streets that aligned roughly SW{\textendash}NE. http://www.springerlink.com/content/y572665mn2j7n828/fulltext.pdf

}, keywords = {Chihuahuan Desert, desert vegetation, desert winds, dunes, dust emissions, flow around and above roughness elements, friction velocity, sand transport, vegetation}, doi = {10.1007/s10652-005-6022-7}, url = {/files/bibliography/06-026.pdf}, author = {D. E. Gillette and Jeffrey E. Herrick and Herbert, G.A.} } @inbook {50446, title = {Water and energy balances within the Jornada Basin}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem. The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {176-188}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {8}, address = {New York}, abstract = {This chapter describes general characteristics and components of the energy and water balances in arid regions, with specific examples from the Jornada Basin. Various research efforts to characterize the energy and water balances and resultant carbon dioxide fluxes in the Jornada Basin are detailed. We provide a brief overview of how plant physiology interacts with energy and water balances in this region. The purpose of this chapter is to characterize the general abiotic conditions and some physiological traits of plants in this semiarid region.}, keywords = {arid, balances, carbon, dioxide, energy, Jornada, regions, water}, url = {/files/bibliography/06-059.pdf}, author = {V. P. Gutschick and K. A. Snyder}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @article {50485, title = {Woody Plant Invasion at a Semi-arid Transition Zone: Importance of Ecosystem Type to Colonization and Patch Expansion}, journal = {Journal of Vegetation Science}, volume = {17}, year = {2006}, note = {Duplicate of ARIS $\#$ 182512}, month = {June 15, 2006}, pages = {389-396}, abstract = {Our objective was to evaluate how patterns in colonization and patch expansion of an invasive woody plant, Larrea tridentata (creosotebush) differ between two grassland ecosystems at a biome transition zone. We sampled frequency of occurrence, height, and surface area of saplings (n=134) and patches of adult plants (n=247) of creosotebush within a mosaic of ecosystems dominated either by the Chihuahuan Desert species, black grama, or the shortgrass steppe species, blue grama, located within 1 km of the creosotebush-dominated ecosystem. Distances between patches and patch area were used to estimate connectivity and propagule pressure. Sapling height and distance to the creosotebush dominated ecosystem were used to estimate patterns in dispersal. Our results show that creosotebush saplings (<1\%) and patches of adults (15\%) occur less frequently in black grama than blue grama-dominated ecosystems. Propagule pressure did not differ with distance from the core creosotebush ecosystem. Evidence was found for both local and long distance dispersal. We conclude that spatial variation in creosotebush saplings and adults at this biome transition zone is related to the different susceptibilities to invasion by the two grassland ecosystems. The persistence of grasslands at this site despite region-wide expansion by creosotebush may be related to the spatial distribution of blue grama-dominated ecosystems that resist or deter invasion by this species.}, keywords = {colonization, ecosystem, semi-arid, transition, woody}, url = {/files/bibliography/06-024.pdf}, author = {Debra C. Peters and Jin Yao and J. R. Gosz} } @proceedings {50503, title = {What does an endophyte look like? Endophyte profiles of native grasses and shrubs}, year = {2006}, month = {June 6-8, 2006}, address = {Cedar City, UT}, abstract = {Obligate fungal endophytes often defy detection and isolation by conventional microbiology techniques. Staining methods, including the use of trypan blue and sudan IV have effectively detected endophytes in plant tissues. However, stains fail to distinguish one fungal endophyte from another, thus obscuring the complexity of plant-endophyte communities. We have successfully separated fungal and plant ribosomal DNA sequences by amplifying plant-extracted DNA with polymerase chain reactions, then separating similar sequences with denaturing gradient gel electrophoresis (DGGE). The resulting electrophoregrams produce specific bands unique for each organism present in a specific plant-endophyte community. DGGE also permits detection of bacterial endophytes. Here we compare the diversity of endophytes populations from in vitro cultures of eight Chihuahuan desert grasses and shrubs. These profiles illustrate the complexity of plant systems previously thought of as single organisms.}, keywords = {DNA, endophytes, fungi, plant tissues}, author = {Ruth L. Sedillo and M.E. Lucero and J.R. Barrow and I. Reyes-Vera} } @conference {50576, title = {Whose genes are we sequencing? Evidence for the presence of multiple genomes in native and regenerated high plants}, booktitle = {American Society of Plant Biologists}, year = {2005}, month = {October 12-16, 2}, pages = {Paper No. 33}, address = {Snowbird, Utah}, abstract = {Plant genome analysis has been traditionally based on an assumption that healthy plants are axenic organisms. With improved techniques for detecting microbial endophytes, evidence supporting the presence of microbial consortia associated with all major plant tissues is mounting. Herein, the isolation and/or detection of seven species of fungi associated with the desert grass, Bouteloua eriopoda are described. Also described are three species of fungi and one bacterium isolated from aseptically cultured Atriplex canescens. The detection of fungal lipids and chitin in more than 40 species, including surface sterilized Arabidopsis thailiana indicate symbioses with asymptomatic endophytes are well conserved in higher plants. In some cases, endophyte DNA sequences have aligned more closely with host plant sequences reported in Genbank than with DNA from related groups of endophytes. For example, a bacterial endophyte independently isolated from A. canescens and A. confertifolia contains a sequence similar to internal spacer rDNA reported for 131 species of the plant family Chenopodiacea. In grasses, teliospore producing endophytes are highly conserved. DNA hybridizing to one such endophyte in B. eriopoda aligns closely with sequences from rice. The overwhelming evidence that higher plants exist as communities interacting with populations of microbial endophytes has powerful implications for plant molecular biologists. It is inadequate to assume that DNA isolated from plant tissues is plant DNA.}, keywords = {DNA, endophytes, fungi, plant genome}, author = {M.E. Lucero and J.R. Barrow} } @proceedings {50745, title = {What does an ecological threshold look like?}, year = {2003}, month = {July 26 - August}, pages = {688-690}, address = {Durban, South Africa}, abstract = {Recent concepts in rangeland health and management emphasize that ecosystem structure may shift abruptly in time once a critical threshold is crossed. Transitions between grasslands and desert shrublands, for example, are thought to be triggered by a combination of high grazing pressure and drought. Once thresholds are crossed, novel constraints prevent reestablishment of historic ecosystem states. Thus, land management policy is being oriented towards identifying and avoiding these thresholds. One problem with implementing such policy is that land managers and ecologists are not sure what critical thresholds are; this stems in part from a lack of conceptual clarity. We argue that thresholds in rangeland structure are not singular phenomena but exist at several levels along a chain of causation. We illustrate this conceptual approach with a study of a grassland-shrubland transition in south-central New Mexico. At the broadest scale (25 km2), the shift from a grass-dominated area to a shrub-dominated area is coincident with a slight change in topographic position, a change in soil texture, and increased channelization. At intermediate scales (100-1000 m2), the maintenance of grass cover is promoted by the presence of patches oriented perpendicularly to the direction of slope, whereas shrubs dominate where patches are elongated in the direction of the slope. At the finest scales (1-10m2), grasses are associated with patches having sandier surface textures, low calcium carbonate at the surface, and higher infiltration rates than shrub-dominated patches. Thus, the causes of the shift from grassland to shrubland are scale-dependent and thresholds in several processes can be identified.}, keywords = {ecological, health, management, rangeland, threshold, transition}, url = {/files/bibliography/03-027Proc.pdf}, author = {Brandon T Bestelmeyer and Joel R. Brown and Jeffrey E. Herrick and Kris Havstad} } @proceedings {50806, title = {What is the standard for rangeland health assessments?}, year = {2003}, month = {July 26-August 1}, pages = {764-766}, address = {Durban, South Africa}, abstract = {Rangeland health encompasses the maintenance of complex ecological processes on rangelands over time. In an attempt to provide a rapid, moment-in-time assessment of rangeland health, we developed the Interpreting Indicators of Rangeland Health approach that uses 17 observable indicators to assess 3 attributes of rangeland health, soil and site stability, hydrologic functioning and biotic integrity. In the initial published version, the standard for comparison for assessing an evaluation area was the Ecological Site Description, the description of physical and biotic characteristics of lands that produce distinctive types and amounts of vegetation and that respond similarly to management. Multiple reference areas provided visual representations of the ecological site and were used to supplement ecological site descriptions or as the standard when ecological site descriptions were not available. We developed an ecological reference worksheet to provide a consistent standard for assessing rangeland health regardless of the availability of a formal ecological site description or a series of reference areas. This worksheet should be completed by a group of experts familiar with the range of variation in soil, hydrologic and biologic indicators. When possible, data similar to that found in ecological site descriptions should be used to generate the range of variation expected for a functioning site. Once the standard range of variation is described, the group should describe the four categories of expected deviations from this standard using generic descriptions of these categories as a guide. We believe this change will allow this technique to be used by experts throughout the world.}, keywords = {assessments, ecological processes, rangeland health, standard}, author = {D.A. Pyke and Jeffrey E. Herrick and P. L. Shaver and M. Pellant} } @conference {50840, title = {What does an ecological threshold look like? Scale-dependent causes of a grassland-shrubland transition}, booktitle = {87th Annual Meeting, Ecological Society of America}, year = {2002}, month = {August 4-9, 2002}, pages = {319}, address = {Tucson, AZ}, abstract = {Recent concepts in rangeland health and management emphasize that ecosystem structure may shift abruptly in time once a critical threshold is crossed. Transitions between grasslands and desert shrublands, for example, are thought to be triggered by a combination of high grazing pressure and drought. Once thresholds are crossed, novel constraints prevent reestablishment of historic ecosystem states. Thus, land management policy is being oriented towards identifying and avoiding these thresholds. One problem with implementing such policy is that land managers and ecologists are not sure what critical thresholds are; this stems in part from a lack of conceptual clarity. We argue that thresholds in rangeland structure are not singular phenomena but exist at several levels along a chain of causation. We illustrate this conceptual approach with a study of a grassland-shrubland transition in south-central New Mexico. At the broadest scale (25 km2), the shift from a grass-dominated area to a shrub-dominated area is coincident with a slight change in topographic position, a change in soil texture, and increased channelization. At intermediate scales (100-1000 m2), the maintenance of grass cover is promoted by the presence of patches oriented perpendicularly to the direction of slope, whereas shrubs dominate where patches are elongated in the direction of the slope. At the finest scales (1-10m2), grasses are associated with patches having sandier surface textures, low calcium carbonate at the surface, and higher infiltration rates than shrub-dominated patches. Thus, the causes of the shift from grassland to shrubland are scale-dependent and thresholds in several processes can be identified.}, author = {Brandon T Bestelmeyer and Joel R. Brown and Kris Havstad} } @inbook {51124, title = {The world beneath our feet: Soil biodiversity and ecosystem functioning}, booktitle = {Nature and Human Society: The Quest for a Sustainable World}, year = {2000}, note = {//??//LTER III// Total pages: 644ppProCite field[6]: In}, month = {2000}, pages = {225-241}, publisher = {National Academy of Sciences Press}, organization = {National Academy of Sciences Press}, address = {Washington, D.C.}, abstract = {

The wealth of soil biodiversity is poorly known on both local and global scales, and thus the importance of soil organisms (microbes to invertebrates) has been largely disregarded in assessments of biodiversity consequences for ecosystem functioning. The huge abundance and numbers of species in soils as well as the diversity of methods required for sampling, extraction and identification of the organisms, have made assessments of diversity of all taxa at even one location extremely difficult. Despite that, we suggest that a better understanding of soil biodiversity and its relationship to critical ecosystem services is vital for planning for sustainable soils for the long term. A multitude of microbes, protozoa, invertebrates and vertebrates interact to maintain soil fertility, decay, recycling of organic matter, the breakdown of hazardous wastes, cleansing of water, the biological control of agricultural and human pests and the composition of the atmosphere. However, we have yet to identify which species play key roles in these processes, even those that may most directly and immediately further the human enterprise through influencing carbon sequestration, erosion control, the quality of food supply and biocontrol of pests. Much of the functioning in soil is carried out by communities of organisms and we need to know more about their structures. Urgency is added to this task because humans, through land use change and pollution, are impacting the biodiversity and functioning of soil organisms as well as that of organisms in interconnected habitats such as groundwaters, riparian and wetland systems, and aboveground habitats. The biotic groups and the ecosystem services we need to understand cross international boundaries and expertise on them is internationally distributed. International efforts are required to (a) synthesize available information on global soil biodiversity and functioning across ecosystems and (b) develop integrated research approaches and new technologies necessary to examine soil biocomplexity, if we are to acquire the information necessary to sustainably manage the soil as a primary natural resource.

}, keywords = {biodiversity, soil, book, books, chapter, chapters, ecosystem function, biodiversity, report, reports, soil, biodiversity}, url = {files/bibliography/JRN00314_0.pdf}, author = {D.H. Wall and R. A. Virginia}, editor = {Raven, P. and Williams, T. A. (eds.)} } @article {51127, title = {Would managing a flerd benefit your bottom line?}, journal = {Pastoral Memo-Southern Rangelands, Agriculture, Western Australia}, volume = {5}, number = {1}, year = {1999}, month = {1999}, pages = {26-27}, abstract = {

Reducing predation losses, cutting conventional fencing costs, eliminating unproductive search time to locate animals and promoting uniform utilisation of the vegetation resource fee all resource managers who practise mixed-species stocking. These four management challenges can be turned into management opportunities when coupled with the ability to modify small ruminant behaviour so they remain close to cattle under free-ranging conditions. Sheep and goat flocks normally forage separate from cattle herds. However, if small ruminants, preferably young animals, are socialised with cattle the adults will form one or more flerds, i.e. small ruminants that consistently remain close to cattle under free-ranging conditions.

}, isbn = {0726-9382}, url = {/files/bibliography/642.pdf}, author = {D.M. Anderson} } @article {JRN54968, title = {Water storage in mountain basins from satellite snow cover monitoring }, journal = {Remote Sensing and Geographic Information Systems for Design and Operation of Water Resources Systems}, year = {1997}, month = {04/1997}, pages = {83-91}, chapter = {83}, abstract = {

The average areal water equivalent of the seasonal snow cover on 1 April in the basin of the Rio Grande at Del Norte, Colorado (3419 km3, 2432-4215 m a.s.l.) is evaluated from periodical snow cover mapping by Landsat. A dry, near-average and wet hydrological year are examined. Snow reserves in terms of water storage volumes are computed in three elevation zones for actual temperatures and for a projected climate change of +4{\textdegree}C. The decrease of snow accumulation in a warmer climate results in a significant increase of the winter runoff and a corresponding decrease of the summer runoff. The computed winter/summer proportions change from 24/76\% to 29/71\% in dry year 1977, from 13/87\% to 28/72\% in the average year 1976, and from 7.5/92.5\% to 12/88\% the wet year 1979. An assessment of the seasonal recession from winter to summer reveals that the actual climate effect is even greater.

}, url = {files/bibliography/Rango1997-02.pdf}, author = {A. Rango and J. Martinec} } @conference {51331, title = {Working together to restore desert rangelands}, booktitle = {International Conference, Society for Ecological Restoration}, year = {1996}, month = {June 17-22, 1996}, pages = {54}, address = {New Brunswick, NJ}, abstract = {We have formed a partnership with local ranchers, environmental groups and government agencies to develop restoration technologies for desertified arid lands. The USDA Agricultural Research Service, Jornada Experimental Range, is a 78,266-hectare desert laboratory located in the northern Chihuahuan Desert. During the last 100 years, much of this area has undergone a transition from desert grasslands to desertified shrublands, a trend that is occurring in most of the world{\textquoteright}s arid lands. In addition to research examining basic ecosystem function, we have set aside 8,259 hectares to be managed by ranchers working with local environmental organizations. Presently, this group is using knowledge of desert ecosystems to create low-cost, restoration technologies for arid lands. Current projects are designed to promote natural restoration processes and include: (1) targeted application or organic waste to enhance soil stability and productivity, (2) placement of watering points that provide a seed source while attracting seed-dispersing wildlife, (3) creation of predator habitat to reduce herbivore pressure during vegetation establishment.}, author = {E.L. Fredrickson and Jeffrey E. Herrick and Kris Havstad and J. A. Winder} } @article {51433, title = {Windows of opportunity in desert ecosystems: Their implications to fungal community development}, journal = {Canadian Journal of Botany}, volume = {73S}, year = {1995}, note = {//??//LTER III//}, month = {1995}, pages = {1407-1414}, abstract = {

At the ecosystem level, all fungal activity in arid and semiarid systems is water regulated. However, as the observation scale is changed to allow for finer resolution of moisture effects, one finds that fungal community development in deserts may be influenced by either the temporal patterning of moisture pulses, or biotic factors that extend the benefits of moisture windows. When selected biocides were applied to the root region of a desert bunchgrass, Erioneuron pulchellum, to reduce microarthropod and nematode densities, fungal species numbers associated with the root surface were not altered. The temporal pattern in species numbers apparently reflect large scale seasonal responses of the fungi, microfauna, and plants to yearly differences in the occurrences of moisture windows. For wood on the soil surface, moisture windows of short duration coupled with high temperatures restrict fungal species composition in this habitat resulting in a lack of turnover in the dominant fungal species on surface wood. However, when wood was placed in the more amenable environment of a woodrat midden, patterns of fungal community development differed significantly from that observed for wood on the soil surface. These studies indicate that our understanding of the roles of fungi in the functioning of desert ecosystems is biased because the scale at which we usually make observations is too large to account for abiotic and biotic influences on fungal activity and community development. Moreover, we have to realize that the occurrence of favorable habitats for fungi in arid systems varies considerably in space and time. One consequence of the high spatial and temporal heterogeneity in favorable habitats is that functional diversity among fungi may be greater than would be predicted based solely on abiotic considerations. Key words: deserts, environmental heterogeneity, functional diversity, scale, wood.

}, keywords = {article, articles, community, fungal, ecosystem, fungal community, fungal community, journal, journals}, doi = {10.1139/b95-404}, url = {files/bibliography/JRN00200.pdf}, author = {J. C. Zak and Sinsabaugh, R. and William P. MacKay} } @mastersthesis {51530, title = {Waterbalance of a bare soil in an arid environment}, year = {1992}, note = {//NMSU//LTER-III//ProCite field[12]: In File}, month = {1992}, pages = {74}, school = {New Mexico Tech, Socorro and Agricultural University, The Netherlands}, type = {M.S. Thesis (DRAFT)pp}, abstract = { Groundwater recharge is the process whereby the surplus or infiltration over evapotranspiration drains from the root zone and continues to flow downward through the unsaturated or so called {\textquoteright}vadose{\textquoteright} zone toward the watertable where it replenishes the groundwater reservoir (Freeze and Cherry, 1979). Arid regions are commonly defined as areas where the potential evapotranspiration exceeds the precipitation most of the time. Because in general there is no excess of infiltration water in these areas and the groundwater table is very deep, the assumption is often made that recharge in desert areas is negligible or non-existing. This assumption has led to the deliberate placement of facilities for land disposals of toxic and radioactive wastes in desert regions, in the expectation that such wastes will remain immobile in the soil (Gee and Hillel, 1988). This might be true for certain areas at certain times, but even in deserts occasional short term periods with heavy rain, as well as the nature of the soil and its vegetative cover can particularly contribute to recharge. These days the need for quantitative determination of groundwater recharge in arid regions is increasing and the ability to efficiently model water flow through unsaturated soils is becoming more important. The objectives of this study are (1) the calibration of the computer program Swacrop for a bare soil and (2) a quantification of the precipitation-recharge process. Swacrop is a transient one-dimensional finite-difference model which simulates the water for the unsaturated zone, with possible root water uptake by vegetation. The water flow is calculated using the Richard{\textquoteright}s equation. Recharge is calculated as the potential recharge and is equal to the sum of the downward flux of water at the bottom of the simulated profile and the change of water storage in the profile.... For the calibration of the model a bare soil lysimeter experiment was used. To prevent the problems of infiltration into very dry soils, the simulation for the first 2 years of the long-term lysimeter experiment are skipped.}, keywords = {dissertation, dissertations, model, groundwater recharge, model, Swacrop, model, waterbalance, soil, groundwater recharge, theses, thesis, transect, groundwater recharge, water, ground recharge}, author = {Hollanders, Peter} } @article {51713, title = {Water and nitrogen effects on growth and allocation patterns of creosotebush in the northern Chihuahuan Desert}, journal = {Journal of Range Management}, volume = {41}, number = {5}, year = {1988}, note = {//NMSU//LTER I//Listed in LTER2 proposal as citing LTER1 support//}, month = {1988}, pages = {387-391}, abstract = {

A field experiment using 2 patterns of irrigation and 1 level of nitrogen fertilizer (10 g-N m-2) was conducted in order to discern water and nitrogen interactions that may control production of creosotebush (Larrea tridentata (D.C.) Cov.). The 2 patterns of irrigation simulated precipitation from small, frequent events (6 mm water added weekly) or large, infrequent events (25 mm water added monthly). Understnaing the factors controlling the production of this rangeland shrub may aid in the development of strategies for management. Vegatative growth occurred mostly during March-May (spring) and August-October (summer-fall). Fruit production occurred mainly in the spring and root growth ocurred mainly in the summer-fall. Irrigation increased vegetative growth and decreased fruit produciton. Responses to irrigation were greater during summer-fall than in the spring. Small, frequent water additions caused larger increases in vegetative plus fruit growth than did large, infrequent water additions. Nitrogen fertilization increased the growth of both vegetation and fruit in irrigated and unirrigated plots. Stem mortality and root growth were not significantly affected by irrigation or nitrogen fertilizer. These results suggest that creosotebush production is limited by both soil moisture and nitrogen availability and that temporal patterns of rainfall may be as important as total amounts.

}, keywords = {article, articles, journal, journals, Larrea,morphology, Larrea,nitrogen amendment, Larrea,phenology, Larrea,rainfall simulation, Larrea,reproduction, nitrogen amendment,Larrea, rainfall simulation,Larrea}, doi = {10.2307/3899572 }, url = {files/bibliography/JRN00088.pdf}, author = {F. M. Fisher and J. C. Zak and Gary L. Cunningham and Walter G. Whitford} } @article {51747, title = {Water budget for creosotebush-infested rangeland}, journal = {Journal of Arid Environment}, volume = {15}, year = {1988}, note = {Full Article from Journal of Arid Environments posted on this website with permission from Elsevier. http://www.sciencedirect.com/science/journal/01401963}, month = {1988}, pages = {71-74}, abstract = {

A water budget for creosotebush-infested rangeland was calculated using values determined from a water interception study, runoff from instrumented plots, and precipitation data. Combining data generated from precipitation events received for the study period showed that 20 per cent and 9 per cent of the rainfall contributed to runoff and interception, respectively. Abstraction of approximately 30 per cent of the precipitation by these two variables impacts the onsite water availability.

}, url = {/files/bibliography/338.pdf}, author = {J.M. Tromble} } @article {51746, title = {Water interception by two arid land shrubs}, journal = {Journal of Arid Environment}, volume = {15}, year = {1988}, note = {Full Article from Journal of Arid Environments posted on this website with permission from Elsevier. http://www.sciencedirect.com/science/journal/01401963}, month = {1988}, pages = {65-70}, abstract = {

Water is a critical commodity in short supply in arid environments. Therefore, its judicious use and disposition is critical for improving the environment both economically and esthetically. Two desert shrubs, creosotebush and tarbush, have invaded former productive grasslands and intercept rainfall that would normally enter the soil and be available for the growth of useful plants. A creosotebush community with 30 per cent crown cover would intercept 12 per cent of the summer rainfall. Native communities of tar bush with approximately 15 per cent crown cover would intercept 6 per cent of the average summer rainfall.

}, url = {/files/bibliography/339.pdf}, author = {J.M. Tromble} } @article {51949, title = {Water properties of caliche}, journal = {Journal of Range Management}, volume = {36}, number = {6}, year = {1983}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {November 1, 1983}, pages = {723-726}, abstract = {

Water absorption and retention by hard caliche nodules (rocks) collected from soils in southern New Mexico were determined. The rate of water uptake by the caliche rocks was rapid and water content at saturation was13.0\% by weight (24.7\% by volume). At a matrix potential of -0.7 MPa, the rocks retained 10.6\% water by weight, an 18\% loss from saturation. Water loss from saturated rocks to a dry atmosphere was slow, but most of the absorbed water was released. The rocks contained only 0.6\% water by weight (1.1\% by volume) after 34 days in a desiccator. Both laboratory and field trials indicated that, although indurated caliche layers will absorb large amounts of water, the water does not pass through the layers to the soil below.

}, url = {/files/bibliography/236.pdf}, author = {J.T. Hennessy and Gibbens, Robert P. and J.M. Tromble and Manual Cardenas} } @article {52004, title = {Wind erosion curtailed by controlling mesquite}, journal = {Journal of Range Management}, volume = {35}, number = {5}, year = {1982}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {September 1, 198}, pages = {563-566}, abstract = {

A sand-dune mesquite area with very \ little interdunal vegetation was treated aerially one to three times with 2,4,5-T at 0.56kg/ha in an oil: water \ emulsion. Four and five years after the initial treatment, the amount of blowing soil was evaluated using sandtraps locatedvarious distances from the \ boundary between sprayed and unsprayed mesquite. The amount of wind-blown particles was greatly reduced on the area chemically treated to control mesquite. During the \ windy season \ the \ amount \ of \ blowing soil \ in \ the unsprayed \ area was more than 15-fold greater than at \ 180 m \ into the sprayed area. Intermediate amounts were measured between boundary and 180 m \ into the treated area.

}, url = {/files/bibliography/217.pdf}, author = {W. L. Gould} } @article {52021, title = {Water ponding for increasing soil water on arid rangelands}, journal = {Journal of Range Management}, volume = {35}, number = {5}, year = {1982}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {September 1, 198}, pages = {601-603}, abstract = {

Ponding \ dikes constructed \ to slow and control the overland flow of runoff \ water were evaluated. \ Infiltration and \ runoff measure- ments from a sprinkling infiltrometer indicated \ no differences between the control \ and the water pending area. Examination of 20 \ years \ of \ precipitation\  \ records \ for \ June \ through \ September showed \ that \ enough \ pending \ events occurred \ to supply an ade- quate \ amount \ of water for \ wetting the soil profile to below the plant \ rooting \ zone. The control \ areas \ were low in available\  soil water even immediately \ following \ precipitation events.

}, url = {/files/bibliography/225.pdf}, author = {J.M. Tromble} } @article {52107, title = {Water-resources information available from New Mexico Bureau of Mines and Mineral Resources}, year = {1980}, note = {//LOCAL//NONE//}, month = {1980}, institution = {New Mexico Bureau of Mines and Mineral Resources}, address = {Socorro, New Mexico}, abstract = {The purpose of this pamphlet is to identify the water-resource information available so that it may be more readily located and used. Table 1 summarizes availability by area of interest. Fig. 1 shows areas covered by comprehensive water-resource reports. The kind of information included in these reports is categorized in table 2. Finally, reports that give only general water availability or very specialized water-resource information are listed in table 3.}, keywords = {book, books, chapter, chapters, report, reports, water resources}, author = {Stone, William J.} } @proceedings {52117, title = {Water quality control from livestock management}, year = {1980}, month = {1980}, pages = {21}, abstract = {Impacts of grazing management systems on watershed values have been determined in few ecosystems in the Southwest or the rest of the country. Generally, deferred-rotation systems increase infiltration rates and decrease runoff and sediment production compared to continuous grazing at comparable stocking rates. Short-duration grazing systems do not increase infiltration rates and decrease runoff and sediment production. "Proper grazing use" and "planned grazing systems" have been approved by the U.S. Environmental Protection Agency as Best Management Practices for New Mexico. Deferred-rotation grazing systems were as favorable for improving watershed values as the exclusion of livestock grazing in some situations.}, keywords = {deferred-rotation, livestock management, short-duration, water quality, watershed}, url = {/files/bibliography/190.pdf}, author = {Wood, M. K. and J.M. Tromble} } @proceedings {52196, title = {Water management on a semiarid native rangeland in the Southwest}, year = {1977}, month = {1977}, pages = {1071}, keywords = {semiarid rangeland, Southwest, water management}, author = {J.M. Tromble and Gibbens, Robert P.} } @conference {52198, title = {Water ponding for increasing soil water}, booktitle = {30th Annual Meeting, Society for Range Management}, year = {1977}, month = {1977}, pages = {51-52}, keywords = {increasing soil water, water ponding}, author = {J.M. Tromble and Gibbens, Robert P. and C.H. Herbel} } @article {52197, title = {Water requirements for mesquite (Prosopis juliflora)}, journal = {Journal of Hydrology}, volume = {34}, year = {1977}, note = {Full Article from Journal of Hydrology posted on this website with permission from Elsevier, Copyright {\textcopyright} 1977; http://www.sciencedirect.com/science/journal/00221694}, month = {1977}, pages = {171-179}, abstract = {Evapotranspiration (ET) determined by different investigators, compared with values determined by the White and Troxell methods, showed that their values provided reasonable estimates and that utilizing diurnal water table fluctuations furnishes a method of computing ET with less than 100\% vegetation density. Average daily maximum ET rates for June were calculated and ratios were compared with values from other independent studies. Since ET rates, determined by White and Troxell methods, indicated plausible values of water use when compared to other independent studies, they could be considered index values useful as guidelines for water abstracted by mesquite.}, keywords = {mesquite, Prosopis juliflora, water requirements}, url = {/files/bibliography/163.pdf}, author = {J.M. Tromble} } @article {52219, title = {Water loss in Chihuahuan Desert ants}, journal = {Physiological Zoology}, volume = {48}, number = {4}, year = {1976}, note = {//NMSU//US-IBP//}, month = {1976}, pages = {390-397}, abstract = {

This study was designed to evaluate differences in desiccation rates in six species of Chihuahuan desert ants as related to size, foraging behavior, and geographical distribution. During the first 8 h of exposure, all species of seed harvesters had similar desiccation rates, and Formica perpilosa, a plant-exudate feeder, had a higher desiccation rate and lower desiccation resistance than the harvesters. Desiccation rate and desiccation resistance were not correlated with foraging behavior in Pogonomyrmex sp. and Novomessor cockerelli but were similar to those of ants from the Sahara Desert. There was no relationship between body size and desiccation rate and resistance, but female sexuals of N. cockerelli had lower rates and greater resistance than workers and male sexuals of the same species.

}, keywords = {ant,behavior, ant,water loss, article, articles, journal, journals}, url = {files/bibliography/76-Physiological Zoology-Whitford.pdf}, author = {Walter G. Whitford and Carol Ann Kay and Aileen Schumacher} } @mastersthesis {52230, title = {Water balance and assimilation efficiency of the horned lizard, Phrynosoma cornutum: a field study}, year = {1975}, note = {//NMSU//NONE//}, month = {1975}, pages = {21}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {Assimilation efficiency, water gain and water loss were estimated for Texas horned lizards (Phrynosoma cornutum) studied in the field. Total water gain by the animals averaged 6.3 mg g-1day-1. The lizards obtained 5.6 mg g-1day-1 (89\%) as preformed water in the food, and metabolic water production amounted to 0.7 mg g-1day-1 (11\%). The combined urinary and fecal loss of 2.7 mg g-1day-1 averaged 43\% of the mean daily intake. Weight losses of the lizards during study periods were taken as evaporative water losses. These averaged 4.3 mg g-1day-1 which was 68\% of the total water intake. Water loss exceded gain by 0.7 mg g-1day-1 at the feeding rate which occurred during this study. The water turnover rate of lizards maintaining weight in the field was estimated at approximately 17.0 mg g-1day-1 by the regression of total water intake on weight change. This value and the assimilation efficiency estimated during this study (37.1\%) were used to calculate the number of harvester ants (Pogonomyrmex rugosus and P. desertorum) required per month by P. cornutum during the summer. This requirement was estimated at from 30,000 ha-1mo-1 to 34,000 ha-1mo-1, which is about 25\% to 28\% of the Autumn standing crop of these ants on the US IBP Jornada validation site (estimated at about 122,000 ha-1).}, keywords = {dissertation, dissertations, lizard, horned lizard,Phrynosoma, lizard,Phrynosoma, lizard,physiology, Phrynosoma,metabolism, Phrynosoma,physiology, theses, thesis}, author = {Edwards, James Wyatt} } @article {52329, title = {Water relations in a desert millipede Orthoporus ornatus (Girard) (Spirostreptidae)}, journal = {Comparative Biochemistry and Physiology}, volume = {42A}, year = {1972}, note = {//??//NONE//}, month = {1972}, pages = {521-535}, keywords = {article, articles, invertebrate,millipedes, journal, journals, metabolism,millipedes, millipede,metabolism, Orthoporus,metabolism}, author = {Crawford, C. S.} } @mastersthesis {52460, title = {Water balance and thermoneutrality in the grasshopper mouse (Onychomys leucogaster)}, year = {1966}, note = {//LOCAL//NONE//}, month = {1966}, school = {New Mexico University}, type = {M.S. Thesis}, address = {Las Cruces, New Mexico}, abstract = {Water balance and thermoneutrality were studied in the grasshopper mouse Onychomys leucogaster. The thermoneutral zone included ambient temperatures ranging from 28 degrees C - 35 degrees C. The upper critical temperature was near 37 degrees C. The mean minimum rate of matabolism was 1.582cc 02/gm./hr. at 10 degrees C. The minimum value of evaporative water loss wa 13 mg. H2O/gm./hr. at 25 degrees C; the mean maximum value was 41.7 mg./gm./hr. at 37 degrees C....Under conditions of total deprivation of water, grasshopper mice maintained weight on a beef liver diet, but weight losses occured on a ground beef diet. The mice lost 12.5\% of their body weight when fed ground beef and stabilized at this point. Behavioral adaptations are probably of greater importance than physiological ones in permitting the grasshopper mice to inhabit the desert.}, keywords = {dissertation, dissertations, Onychomys,physiology, physiology,Onychomys, rodent, grasshopper mouse,Onychomys, rodent,Onychomys, theses, thesis}, author = {Marsha R. Conley} } @mastersthesis {52461, title = {Water requirement and production of eight desert plant species under four soil levels}, year = {1966}, note = {//??//NONE//}, month = {1966}, pages = {45}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, plant, productivity, plant, water requirement, soil,plant productivity, theses, thesis}, author = {DeGarmo, Harlan Cecil , Jr.} } @article {52561, title = {What calf crop for profit?}, journal = {The New Mexico Stockman}, volume = {9}, year = {1944}, month = {June 1944}, pages = {3, 5, 6}, abstract = {Two visitors always welcomed by cattlemen are a good rain and a new born calf. Obviously, the occurrence of rain is beyond man{\textquoteright}s influence, but the number of curly-haired, wobbly-kneed calves that appear each spring is, to a considerable extent, within his control. During the early days of the cattle industry in the Southwest, when large numbers of cattle drifted at will on the open range, a 30 or 40 percent calf crop was considered fairly good. However, with the advent of barbed wire and more intensive ranching methods, including some reduced stocking, calf crops have steadily increased until an average of 75 percent or better for a locality is not uncommon and on some ranches even higher rates of increase are obtained. Like a manufacturing enterprise, the Southwestern cattle ranch, with its rangeland, saddle and work stock, improvements and equipment, and its carefully selected breeding herd represents a plant in which capital is invested to turn out a finished product--the calf. Whether the calf is turned into beef or is used for replacement, all the energies and efforts of the enterprise are dedicated to turning out the greatest possible number of high quality calves. For the ranch as well as the factory, the economic story is told by the quantity and quality of the product together with the cost of production and the price received. Profits on a cattle ranch are increased not so much by depending upon an increase in price of the product as by bettering the product quality, increasing the rate of production, and reducing costs.}, keywords = {calf crops, cattle industry, profits, quantity and quality}, url = {/files/bibliography/065.pdf}, author = {F.N. Ares and Martin, S.C.} } @article {52566, title = {What does a range calf cost?}, journal = {The New Mexico Stockman}, volume = {8}, number = {12}, year = {1943}, month = {December 1943}, pages = {3-4}, abstract = {Wartime demands for beef and hides are great. Market prices for live animals have been extremely favorable. How long they remain so is questionable in view of the dense numbers of livestock on hand and extreme shortages in feed supplies and protein supplements. Reduction of breeding to the point where they can be maintained entirely on range forage is imperative. In view of the present shortages of supplies and equipment and rising costs of labor and taxes, it is also imperative for the rancher to make a close scrutiny of his operational expenses. An analysis of operating expenses will give a detailed picture of the cost of each item produced. Such an analysis is often helpful in indicating the adjustments necessary in order to increase efficiency and economy.}, keywords = {beef, cattle, market prices, operating expenses, wartime}, url = {/files/bibliography/060.pdf}, author = {F.N. Ares} } @article {52568, title = {What is conservative grazing?}, journal = {The Cattleman}, volume = {29}, number = {12}, year = {1943}, month = {May 1943}, pages = {16, 18}, abstract = {Perhaps not in all the history of the western range has the wise use of forage been so vital as it is today. Increased marketing of beef are essential not only for our armed forces and Allies but also to sustain the home front. This requires an assured sustained output of beef. To this end, we must use our ranges to the greatest advantage for all. Conservative grazing is the practical answer. Considerable has been written regarding conservative grazing, particularly the benefits of this practice in terms of increased beef production. We have read about the Jim Black case in southern New Mexico--how his cattle numbers were reduced more than two-thirds from 18,819 to 6,190 head and yet, with a third as many animals in his herd, produced more pounds of beef, the result of stocking more in accordance with the forage supply (New Mexico Stockman, April 1942). We have also read about Al Dick in the Northwest and how, through judicious grazing, he has restored his range to a high state of productivity and has accomplished an outstanding feat in range management, both as regards livestock production and range productivity (The Cattleman, December 1942). Many other examples may be cited.}, keywords = {conservative grazing, increased beef production, judicious graziing, stocking}, url = {/files/bibliography/062.pdf}, author = {Canfield, R.H.} } @article {52589, title = {Ways and means to minimize the ill effects of drought on black grama ranges}, number = {Research Note 82}, year = {1939}, month = {1939}, pages = {7}, institution = {USDA, Forest Service, Southwest Forest and Range Experimental Range Station}, abstract = {Black grama ranges of southern New Mexico and adjacent portions of Arizona and Texas have the largely unmerited reputation of being excessively vulnerable to drought. Actually, a complete failure of the forage crop is as rare here as is the complete failure of crops in regions of higher rainfall. Climatic data support this statement and provide the best index to the frequency of lean years. Long-time precipitation records taken at the Jornada Experimental Range and supporting experience indicate that each 10-year period may be expected to include 1 year of drought and 2 or more critically dry years. During these dry years the forage growth is far below that of the average year. Forage estimates and grazing capacity figures indicate that the feed supply will vary 60 percent or more between good and poor years. With complete annual use, the current forage crop cannot always be depended on year in and year out to support an unvarying number of cattle. Clearly, if sustained grazing capacity is to be maintained, the feed produced in drought years must be supplemented in some manner.}, keywords = {black grama, drought, effects, research notes}, url = {/files/bibliography/051.pdf}, author = {Canfield, R.H.} } @mastersthesis {52632, title = {Water availability and grass root distribution in selected soils}, year = {1925}, note = {//??//NONE//}, month = {1925}, pages = {67}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, keywords = {dissertation, dissertations, grass,root distribution, grass,water availability, soil,grass root distribution, soil,water availability, theses, thesis}, author = {Bailey, Oran F.} }