@article {JRN55312, title = {Use of PhenoCam Measurements and Image Analysis to Inform the ALMANAC Process-based Simulation Model}, journal = {Journal of Experimental Agriculture International}, volume = {43}, year = {2021}, month = {07/05/2021}, pages = {120-144}, abstract = {Near-surface remote sensing has been used to document seasonal growth patterns (i.e., phenology) for plant communities in diverse habitats. This study quantified greenness from PhenoCam image time series, and applied Beer{\textquoteright}s law with established extinction coefficients to compare leaf area index (LAI) development with the ALMANAC model. We examined patterns and modeled LAI at eight agroecosystem sites as part of the Long-Term Agroecosystem Research (LTAR) network selected for their diversity and amount of and quality of available data. Regions of interest (ROIs) in PhenoCam images were used to derived Green Chromatic Coordinate (GCC) at each site. Next, photos were analyzed in the L*A*B* color space in ImageJ to determine greenness and then the site was simulated in ALMANAC. Finally, the GCC and greenness data were converted to LAI and compared with modeled LAI. Results indicate that PhenoCam time series imagery can be used to improve parameters for leaf area development in ALMANAC by adjusting parameter values to better match LAI derived values in diverse environments. Soybeans, mesquite, and maize produced the most successful match between the model simulations and PhenoCam data out of the eight species simulated. This study represents, to our knowledge, the first independent evaluation of the ALMANAC process-based plant growth model with imagery in agroecosystems available from the PhenoCam network. The results show how PhenoCam data can make a valuable contribution to parameter determination in process-based models, making these models much more realistic. The impact of these conclusions can be increased as the methods are further refined.}, keywords = {PhenoCam Network; ALMANAC model; ImageJ; phenology; green chromatic coordinate; Leaf Area Index (LAI)}, url = {files/bibliography/21-029.pdf}, author = {Jacqueline Jacot and J.R. Kiniry and Amber S. Williams and Addison Coronel and Jianzhong Su and Gretchen R. Miller and Binayak Mohanty and Amartya Saha and Nuria Gomez-Casanovas and Jane M. F. Johnson and Dawn M. Browning} } @article {JRN55269, title = {The Hidden Costs of Land Degradation in US Maize Agriculture}, journal = {Earth{\textquoteright}s Future}, volume = {9}, year = {2021}, month = {02/2021}, pages = {1-19}, chapter = {1}, abstract = {The United States is a world leader in the production of maize and other crops and the agricultural success of the country is directly linked to the intensive use of fertilizers and irrigation. However, even in advanced agricultural systems, soils can become degraded over time due to factors such as soil organic matter (SOM) loss and erosion. Here, we use a series of scenario-based model analyses to show that about one-third of current annual US. N fertilizer use in maize agriculture is used to compensate for the long-term loss of soil fertility through erosion and organic matter loss. This leads to over a half billion dollars per year in extra fertilizer supply costs to US farmers. These results highlight the potential to reduce both the input costs and environmental impacts of agriculture through the restoration of SOM in agricultural soils.}, doi = {https://doi.org/10.1029/2020EF001641}, url = {files/bibliography/21-005.pdf}, author = {Jang, W.S. and J. Neff and Y. Im and Doro, L. and Jeffrey E. Herrick} } @conference {JRN55203, title = {fDNA-based diet selection by Raramuri Criollo and Angus crossbreeds in the Chihuahuan Desert}, booktitle = {Society for Range Management}, year = {2020}, month = {02/2020}, address = {Denver, CO}, abstract = {A 3-year diet study was conducted in two pastures on the Jornada Experimental Range in the northern Chihuahuan Desert, Dona Ana County, New Mexico, USA to compare diets of Raramuri Criollo and Angus x Hereford crossbreed cattle. Fecal samples were collected directly from cattle and analyzed with both Operational Taxonimic Units (OTUs) and Exact Sequence Variants (ESVs). ESVs performed better than OTUs at discriminating between plant taxa. Although patterns of plant preference between the two breeds were not necessarily constant over time, Criollo diets were were found to have proportionally more Honey mesquite (Prosopis glandulosa) and proportionally less Black grama (Bouteloua eripoda) than Angus x Hereford crossbreeds. In general, both breeds consumed proportionally more grass in the winter than in the summer. However, the grass component for both breeds decreased over time, likely due to persistent drought which caused less grass production and availability. Both breeds behaved the same way by replacing the grass component with forbs in the summer and with shrubs in the winter. This study is an example of how fecal DNA analyses can illustrate how livestock alter their diets to cope with drought.}, author = {D. K. James and Richard E. Estell and Andr{\'e}s F. Cibils and S. Spiegal and S. Nyamuryekung{\textquoteright}e and Matthew M. McIntosh and Amy L. Gonzalez and Kirsten B. Romig} } @article {JRN55133, title = {Constraints on shrub cover and shrub-shrub competition in a U.S. southwest desert}, journal = {Ecosphere}, volume = {10}, year = {2019}, month = {02/2019}, pages = {1-16}, chapter = {1}, abstract = {

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

}, keywords = {Jornada Basin Long-Term Ecological Research (LTER), shrub-shrub competition, Southwest U.S. drylands, Special Feature: Dynamic Deserts, woody plant encroachment}, doi = {doi.org/10.1002/ecs2.2590}, url = {files/bibliography/19-014.pdf}, author = {W Ji and Niall Hanan and Dawn M. Browning and Curtis H. Monger and Debra C. Peters and Brandon T Bestelmeyer and Steven R. Archer and Ross, C. Wade and Lind, Brianna M. and Julius Anchang and Kumar, Sanath S. and Prihodko, Lara} } @article {JRN54903, title = {Make a difference: ecology careers in federal agencies}, journal = {Frontiers in Ecology and the Environment}, year = {2018}, month = {01 August 2018}, doi = {https://doi.org/10.1002/fee.1926}, author = {Mari-Vaughn V. Johnson and J Strickland and Jeffrey E. Herrick} } @article {JRN54949, title = {Innovation in rangeland monitoring: annual, 30 m, plant functional type percent cover maps for U.S. rangelands, 1984{\textendash}2017}, journal = {Ecosphere}, volume = {9}, year = {2018}, month = {09/2018}, pages = {1-19}, chapter = {1}, abstract = {

Innovations in machine learning and cloud-based computing were merged with historical
remote sensing and field data to provide the first moderate resolution, annual, percent cover maps of plant
functional types across rangeland ecosystems to effectively and efficiently respond to pressing challenges
facing conservation of biodiversity and ecosystem services. We utilized the historical Landsat satellite
record, gridded meteorology, abiotic land surface data, and over 30,000 field plots within a Random
Forests model to predict per-pixel percent cover of annual forbs and grasses, perennial forbs and grasses,
shrubs, and bare ground over the western United States from 1984 to 2017. Results were validated using
three independent collections of plot-level measurements, and resulting maps display land cover variation
in response to changes in climate, disturbance, and management. The maps, which will be updated annually
at the end of each year, provide exciting opportunities to expand and improve rangeland conservation,
monitoring, and management. The data open new doors for scientific investigation at an unprecedented
blend of temporal fidelity, spatial resolution, and geographic scale.

}, keywords = {cloud computing, conservation, Google Earth Engine, grazing, land cover, landsat, machine learning, rangeland, remote sensing, Time series, wildfire}, doi = {doi.org/10.1002/ecs2.2430}, url = {files/bibliography/18-021.pdf}, author = {Matthew O. Jones and Brady W. Allred and David E. Naugle and J. Maestas and Donnelly, Patrick and Loretta Metz and Jason W. Karl and Smith, Rob and Brandon T Bestelmeyer and Chad S. Boyd and Kerby, Jay D. and McIver, James D.} } @conference {JRN54625, title = {From linear to generalized linear mixed models: A case study in repeated measures}, booktitle = {2016 American Statistical Association (ASA) Conference on Statistical Practice}, year = {2016}, month = {02/2016}, publisher = {2016 American Statistical Association (ASA)}, organization = {2016 American Statistical Association (ASA)}, address = {San Diego, CA}, abstract = {

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

}, author = {D. K. James} } @conference {JRN54444, title = {Implementing AIM-based monitoring for natural resource management}, booktitle = {68th Annual Meeting of the Society for Range Management}, year = {2015}, month = {02/2015}, publisher = {Sociiety for Range Management}, organization = {Sociiety for Range Management}, address = {Sacramento, CA}, abstract = {

Successful monitoring programs are built on clearly-defined objectives, thorough planning, and organized implementation. However, natural resource management decisions need to be made at many different organizational levels and scales {\textendash} from local to national. Developing separate monitoring programs to address each of these levels can be an inefficient and costly approach. We present the monitoring process model that is used for design and implementation of Bureau of Land Management{\textquoteright}s (BLM) Assessment, Inventory, and Monitoring (AIM) monitoring projects. The AIM program provides a framework for collecting monitoring data which can be used many times for many objectives (e.g., land health assessments, Sage-grouse [Centrocercus urophasianus] habitat monitoring, grazing management). This framework places an emphasis on designing and implementing robust monitoring programs. While coordinated monitoring across scales is not always possible, the basic AIM principles (standardized core indicators and methods, statistically-valid sample designs, effective data management, and thorough documentation of the monitoring process) facilitate the use of monitoring data to answer the original objectives and allow for merging of monitoring data between efforts to meet additional objectives. The AIM monitoring implementation framework breaks the development and implementation of monitoring down into a series of achievable, iterative and documentable steps. These steps include: developing management and monitoring objectives; defining the monitoring area, stratification approach, and reporting requirements; selecting indicators and methods; developing data management and quality assurance/control procedures; establishing monitoring locations and collecting and evaluating monitoring data; and analyzing and interpreting monitoring results. Further, we discuss the various roles and skills needed for implementing a monitoring program. We illustrate the implementation steps and roles with examples from AIM projects in northern California and southern Idaho designed to inform land health assessments and evaluations of Sage-grouse habitat. Finally, we showcase tools, databases, and best practices available to assist in implementing AIM monitoring.

}, author = {D. K. James and Sarah McCord and Emily Kachergis and Jeffrey E. Herrick} } @proceedings {JRN54574, title = {Investigating biochar as a tool for mine soil remediation}, year = {2014}, month = {08/2014}, publisher = {National Conference on Mining-Influenced Waters}, address = {Albuquerque, New Mexico}, abstract = {Biochar is a cost-effective, carbon negative soil amendment that can lead to improved soil quality. Research has also demonstrated the efficacy of biochar to sorb heavy metals and agricultural chemicals from contaminated soils, thus effectively reducing the potential for metal and chemical contamination of surface and ground waters. In this study we investigated the ability of biochar produced from a single feedstock (Doulas fir wood chips) across a range of charring temperatures (300 {\textendash} 700 {\textdegree}C) to bind with metals. Our goal in this research is to link metal sorption to specific biochar properties, and then use these relationships to engineer biochar with specific properties to achieve various remediation and soil quality outcomes. We characterized our biochars using a variety of techniques including total elemental analysis, pH, FTIR spectroscopy, surface area and pore size analysis, and proximal carbon analysis. We used batch experiments of biochar with either Cu (II) solutions or simulated rainwater extracts of soils contaminated with mine tailings to investigate metal sorption. Sorbed metals were characterized using synchrotron-based XAS, XANES, EXAFS and XRF-Tomography. We found that higher temperature biochars, while having a decreased abundance of oxygen containing functional groups, had an increased capacity for metal sorption over biochar produced at lower temperatures. Concomitantly, these biochars also have greater ash contents, surface areas, abundance of small pores and higher pH values. Results of our sorption studies indicate that metal sorption on biochar may be competitive and preferential, and that as the charring temperature goes up, physisorption may become more important as a mechanism of metal sorption to biochar. }, author = {Mark Johnson and Jonathan Maynard and Nico, Peter} } @article {50229, title = {Landscape position moderates how ant nests affect hydrology and soil chemistry across a Chihuahuan Desert watershed}, journal = {Landscape Ecology}, volume = {23}, year = {2008}, month = {11/2008}, pages = {961-975}, chapter = {961}, abstract = {

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

}, keywords = {infiltration, Landscape scale, macropores, soil nutrients, Sorptivity}, doi = {10.1007/s10980-008-9251-6}, url = {/files/bibliography/08-039.pdf}, author = {Angela James and Edridge, D.J. and T. B. Koen and Walter G. Whitford} } @article {50674, title = {Comparison of land surface emissivity and radiometric temperature derived from MODIS and ASTER sensors}, journal = {Remote Sensing of Environment}, volume = {90}, number = {2}, year = {2004}, month = {March 30, 2004}, pages = {137-152}, abstract = {

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

}, doi = {10.1016/j.rse.2003.11.015}, author = {Jacob, F. and Petitcolin, F. and T. J. Schmugge and Vermote, E. and A.N. French and Ogawa, K.} } @article {50789, title = {Desertification and biopedturbation in the northern Chihuahuan Desert}, journal = {Journal of Arid Environments}, volume = {53}, number = {1}, year = {2003}, month = {January 1, 2003}, pages = {1-14}, abstract = {

We examined the relationship between biopedturbation (animal-caused soil disturbance) and several vegetation and soil-based indicators of rangeland condition to evaluate the effects of desertification on animal soil disturbance. The area, volume, and abundance of various biopedturbation types were assessed at 117 sites in south-central New Mexico where vegetative cover and composition had previously been measured. There were significant relationships between biopedturbation and selected rangeland condition indicators. Increasing percentages of grass cover were positively associated with increasing total area of biopedturbation. Increasing percentages of shrub cover and mean bare patch size were negatively associated with total biopedturbation area. Biopedturbation area and volume were related to indicators of rangeland condition and percent shrub cover best predicts the area of soil disturbed by animals. This relationship, however, cannot reliably predict total biopedturbation area or the area of soil disturbance types.

}, keywords = {Biopedturbation, Chihuahuan Desert, condition indicators, desertification, disturbance, rangeland, soil}, doi = {10.1006/jare.2002.1022}, url = {/files/bibliography/03-009.pdf}, author = {E. Jackson and Krogh, S.N. and Walter G. Whitford} } @conference {50897, title = {Desertification and biopedturbation in the Chihuahuan Desert}, booktitle = {87th Annual Meeting, Ecological Society of America}, year = {2002}, month = {August 4-9, 2002}, pages = {369}, address = {Tucson, AZ}, abstract = {We examined the relationship between biopedturbation (animal-caused soil disturbance) and several vegetation- and soil-based indicators of rangeland health to evaluate the effects of desertification on animal soil disturbance. The area, volume and abundance of various disturbance types were assessed at 117 sites in south-central New Mexico where vegetative cover and composition had been previously measured. There were significant relationships between biopedturbation and selected rangeland health indicators. Increasing percentage of shrub cover and bare patch size were both negatively associated with total soil disturbance area. Shrub cover best predicted the area of soild disturbed by animals. This relationship, however, cannot reliably predict total biopedturbation area or the area of soil disturbance types.}, author = {E. Jackson and Walter G. Whitford} } @conference {51012, title = {Managing rangelands: Implications of a paradigm shift in the ecology of arid and semiarid ecosystems}, booktitle = {86th Annual Meeting, Ecological Society of America}, year = {2001}, month = {August 5-10, 200}, pages = {21}, address = {Madison, WI}, abstract = {Arid and semiarid ecosystems often exhibit unanticipated, nonlinear responses to environmental events and to management activities. While the importance of nonlinear dynamics and thresholds has been widely documented, most rangeland management is still based on the classical Clementsian understanding of succession and retrogression. The objectives of this talk kare to review how recent ecological theory has been integrated into resource management, to identify the scientific and nonscientific limitations of this integration and, based on these limitations, to define types of research land managers need to effectively apply modern ecological theory. The concept of multiple states and transitions is being integrated into revisions of the ecological site descriptions of the Natural Resource Conservation Service. The Bureau of Land Management is implementing the concept of thresholds in their qualitative rangeland health assessments. A Amore complete integration into resource management is limited by a poor understanding of states, transitions and thresholds in many arid and semi-arid ecosystems, and the lack of scientifically-based protocols for selecting management options when uncertainty exists about the presence and relationship to one or more thresholds. These limitations are compounded by administrative structures and competing resource demands. Ecological research is needed to clearly define environmental factors that control states, transitions, and thresholds for the variety of rangeland ecosystems. Adaptive management is paramount and will require collaboration among scientists and managers to successfully apply these increasingly complex models.}, author = {L. A. Joyce and D.A. Pyke and Jeffrey E. Herrick} } @article {51087, title = {Multivariate characterization of perennial vegetation in the northern Chihuahuan Desert}, journal = {Journal of Arid Environments}, volume = {44}, number = {3}, year = {2000}, month = {March 1, 2000}, pages = {305-325}, abstract = {

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

}, keywords = {Chihuahuan Desert, Larrea tridentata, perennial vegetation, prosopis glandulosa}, doi = {10.1006/jare.1999.0597}, url = {/files/bibliography/00-005.pdf}, author = {A. R. Johnson and S.J. Turner and Walter G. Whitford and A.G. de Soyza and Justin Van Zee} } @inbook {51162, title = {Soil water and temperature status}, booktitle = {LTER Soil Methods Standardization}, year = {1999}, note = {// //LTER III//ProCite field[6]: In}, month = {1999}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {Oxford}, abstract = {

Soil water status and temperature are critical factors that affect the activity of organisms in soils. Soil water content also has important effects on the quantity of water that eventually becomes available to surface water, both through its influence on infiltration/runoff relationships (wet soils have lower infiltration rates) and because of its potential contribution to the groundwater. Soil temperature influences soil water availability, the growth rates of plants and microorganisms, and rates of chemical/biochemical reactions.

A number of useful soil physics texts are available that cover the general theory and application of soil water and temperature (e.g., Baver et al. 1972; Hillel 1980a, 1980b; Marshall and Holmes 1988).\  In addition, several books contain detailed summaries of current measurement techniques (Klute 1986; Smith and Mullins 1991; Topp et al. 1992). These references should be used to supplement material in this chapter.

Soil water content has been measured for many years. Earliest measurements were semi quantitative. To the experienced fieldworker, the appearance and feel of the soil can provide valuable information on the amount of water it contains, especially the total water content. Wet soils are generally darker than dry soils and feel "smoother" and heavier. However, appearance and feel can be deceiving. Furthermore, they do not provide quantitative measures of soil water status. Earliest measures of soil water content involved collecting a moist field sample, weighing it, drying it in air or in an oven, and determining the weight loss. Weight loss on drying at 100- 110 {\textdegree}C is usually attributable to water evaporation. The ratio of weight loss to dry weight has been termed gravimetric soil water content.

}, keywords = {book, books, chapter, chapters, report, reports, soil temperature, soil, methods, soil, moisture, technique, soil methods, technique, soil temperature, technique, soil water}, author = {W. M. Jarrell and Armstrong, D. and D. Grigal and E. Kelly and Curtis H. Monger and D. Wedin}, editor = {Robertson, G. P. and Coleman, D. C. and Bledsoe, C. S. and P. Sollins} } @article {51454, title = {Fruit abortion in Yucca elata and its implications for the mutualistic association with yucca moths}, journal = {Oikos}, volume = {69}, year = {1994}, note = {//NMSU//LTER II//}, month = {1994}, pages = {207-216}, abstract = {

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

}, keywords = {article, articles, insect, Tegeticula, insect, yucca moth, journal, journals, Tegeticula, Yucca pollination, yucca moth, SEE , Yucca, fruit abortion, Yucca, mutualism, Yucca, pollination, Yucca, yucca moth}, doi = {10.2307/3546140}, url = {files/bibliography/94-Oikos-Whitford.pdf}, author = {Craig D. James and Hoffman, M. Timm and David C. Lightfoot and Gregory S. Forbes and Walter G. Whitford} } @article {51490, title = {Pollination ecology of Yucca elata: an experimental study of a mutualistic association}, journal = {Oecologia}, volume = {93}, year = {1993}, note = {//LOCAL//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1993}, pages = {512-517}, abstract = {

The pollination biology of a population of 250 Yucca elata and the prodoxid yucca moth Tegeticula yuccasella have a mutualistic association that is essential for the successful sexual reproduction of both species. However, a wide range of other invertebrate species visit flowers during the day and at night. Our aim was to quantify the role of yucca moths and other invertebrate visitors in pollination and fruit set, using manipulative field experiments. Inflorescences were bagged during the day or night (N= 12 Inflorescences) to restrict flower visitors to either nocturnal or diuranl groups. Yucca moths were active exclusively nocturnally during the flowering period and thus did not visit Inflorescences that were unbagged during the day. None of the 4022 flowers exposed only to diurnal visitors set fruit, whereas 4.6\% of the 4974 flowers exposed only to nocturnal visitors (including yucca moths) produced mature fruit. The proportion of flowers production fruit in the latter treatment was not significantly different from unbagged control Inflorescences. In a series of experimental manipulations we also determined that: (1) flowers opened at dusk and were open for tow days on average, but were only receptive to pollen on the first night of opening; (2) pollen must be pushed down the stigmatic tube to affect pollination; and (3) most plants require out-cross pollination to produce fruit. The combination of these results strongly suggests that yucca moths are the only species affecting pollination in Y. elata and that if another species was to affect pollination, it would be a rare event.

}, keywords = {article, articles, invertebrate, Tegeticula, invertebrate, yucca moth, journal, journals, mutualism, plant, Yucca, pollination ecology, Tegeticula, Yucca, yucca moth, Tegeticula, Yucca, pollination ecology}, doi = {10.1007/BF00328959}, url = {files/bibliography/93-Oecologia-Whitford.pdf}, author = {Craig D. James and Hoffman, M. Timm and David C. Lightfoot and Gregory S. Forbes and Walter G. Whitford} } @book {51534, title = {Desertification}, series = {Encyclopedia of Earth Science}, year = {1992}, note = {//??//LTER II//Listed in LTER3 proposal as citing LTER2 support// Updated 12/17/2005ProCite field[6]: In}, month = {1992}, publisher = {Academic Press}, organization = {Academic Press}, address = {San Diego}, keywords = {book, books, chapter, chapters, desertification, report, reports}, author = {W. M. Jarrell} } @mastersthesis {51574, title = {Evaluation of hydraulic roughness coefficient from field and laboratory data}, year = {1991}, note = {//NMSU//NONE//}, month = {1991}, pages = {147}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {Rainfall simulation experiments were performed on a number of 1 m by 1 m plots in the field using rainfall simulator at sites throughout New Mexico and eastern Arizona. Using a point frame device, data were collected on the roughness and cover of each plot. From equilibrium condition hydrographs, hydraulic roughness coefficients were calculated for each plot. The hydraulic roughness coefficient was then related to different surface characteristics and flow variables. Total surface cover density, surface random roughness, and flow Reynold{\textquoteright}s number were found to be the main variables affecting hydraulic roughness coefficient with total surface cover density as the single most important variable.}, keywords = {dissertation, dissertations, hydrology, hydraulic roughness, hydrology, rainfall simulation, rainfall simulation, hydraulic roughness, theses, thesis}, author = {Jorat, Saeed M.} } @article {51669, title = {Ecology of fast-growing and slow-growing mesquite nodulating rhizobia in Chihuahuan and Sonoran desert ecosystems}, journal = {Soil Science Society of America Journal}, volume = {53}, number = {2}, year = {1989}, note = {//NMSU, USDA//LTER II//Listed in LTER3 proposal as citing LTER2 support//}, month = {1989}, pages = {543-549}, abstract = {

Prosopis glandulosa (mesquite) is effectively nodulated by both fast-growing (FG) and slow-growing (SG) rhizobia. The distribution of indigenous, free-living, FG and SG rhizobia, and their morphological and symbiotic characteristics associated with the rooting systems of mesquite were investigated. The three warm desert ecosystems studied were an arroyo, a sand dune, and a playa in the Chihuahuan Desert of New Mexico, and a sand dune and playa in the Sonoran Desert of southern California. The FG rhizobia dominated free-living rhizobial population from 0- to 8-m depth, at the New Mexico playa. In contrast to the New Mexico playa, the surface 1 m soil under mesquite at the California playa was dominated by SG rhizobia, otherwise FG rhizobia dominated to 9-m depth. Slow-growing rhizobia dominated the lowest depths of the mesquite rooting system in both playas. Slow-growing rhizobia dominated the entire rooting zone of both sand dune ecosystems. Fast-growing rhizobia dominated the upper 2 m and SG rhizobia dominated below 2 m in the mesquite rooting zone at the New Mexico arroyo. Regression analysis indicated that the distribution of FG and SG rhizobia was related to the concentration of total soil salts (electrical conductivity) (r2 = 0.20). Chi-square analysis of the distribution of colony morphologies indicated distinct rhizobial populations in each ecosystem. The FG rhizobial population at the New Mexico playa was highly effective and had a high frequency of Hup+ phenotypes. The FG rhizobia isolated from the arroyo were, in contrast, less effective and had a low frequency of Hup+ phenotypes. The SG rhizobial population at the New Mexico dune system was, in contrast, mainly ineffective and had a low frequency of Hup+ phenotypes. The relationship between the variable distribution of FG and SG rhizobia and environmental factors associated with the ecosystems is discussed.

}, keywords = {article, articles, journal, journals, Prosopis, rhizobia, rhizobia, Prosopis-nodulating}, url = {files/bibliography/JRN00093.pdf}, author = {Jenkins, Michael B. and R. A. Virginia and W. M. Jarrell} } @article {51725, title = {Depth distribution and seasonal populations of mesquite-nodulating rhizobia in warm desert ecosystems}, journal = {Soil Science Society of America Journal}, volume = {52}, number = {6}, year = {1988}, note = {//NMSU, USDA//LTER II//}, month = {1988}, pages = {1644-1650}, abstract = {

Deeply rooted woody legumes are common in desert ecosystems yet little is known about the distribution of their rhizobial symbionts in relation to their roots and soil properties of the systems. The distribution of mesquite (Prosopis glandulosa Torr.)- nodulating rhizobia was investigated to depths of 13 m in warm desert eco systems. Soils were collected under mesquite from sand dune and playa ecosystems in the California Sonoran Desert, and from sand dune, playa, arroyo, and grassland ecosystems in Ten Chihuahuan Desert of southern New Mexico. A Larrea tridentata (DC.) Coville (creosote bush) ecosystem in New Mexico, containing no mesquite, was sampled as a reference. Three intact soil cores from each ecosystem were removed during the winter, spring, and fall from the New Mexico sites, and the winter from the California sites. Significant rhizobial population densities were measured in soil from 1- to 4-m depths at the sand due, arroyo, and the playa ecosystems. Tat the playa ecosystem in New Mexico population densities \>105 cells kg-1 were measured in soils from 8-m depth, and root nodules containing rhizobia were recovered in soil samples from 3-, 4-, and 7-m depths. Multiple-regression analysis of rhizobial concentration against soil NH4-N, PO4-P, electrical conductivity, and gravimetric water content indicated that no single soil factor was related significantly to rhizobial concentration across the ecosystems. Rhizobial densities varied with season in the dune and arroyo ecosystems. In these desert ecosystems significant rhizobial populations, root nodules, and presumable symbiotic N2 fixation occur at soil depths rarely studied.

}, keywords = {article, articles, journal, journals, plant, Prosopis, Prosopis, nodulating rhizobia, rhizobia, Prosopis-nodulating}, doi = {10.2136/sssaj1988.03615995005200060026x}, url = {files/bibliography/JRN00073.pdf}, author = {Jenkins, Michael B. and R. A. Virginia and W. M. Jarrell} } @mastersthesis {52090, title = {Factors affecting seed germination and seedling establishment of broom snakeweed}, year = {1980}, note = {//NMSU//NONE//}, month = {1980}, pages = {101}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {A study was conducted to test the effects of scarification, stratification, scorching, leaching and soaking treatments on broom snakeweed (Xanthocephalum sarothrae) germination. Broom snakeweed litter and aqueous extracts of this litter were applied to seeds of broom snakeweed and associated species under growth chamber and greenhouse conditions. Broom snakeweed germination responded best when no physical modification of the seeds occurred. Mean germination of water-soaked seeds was 55\%. Scarification did not reduce germination, but all other physical treatments resulted in substantially lower germination. Results of broom snakeweed litter treatments were inconclusive, probably due to slow leaching of potential chemical inhibitors from the plant material. However, aqueous extracts of broom snakeweed litter reduced germination and shoot and root length of blue grama (Bouteloua gracilis) and sideoats grama (B. curtipendula), when applied at concentrations that represented natural litter fall from broom snakeweed canopy covers of 20\% or greater. Allelopathy may be a factor whereby broom snakeweed reduces grass production and enhances its own life cycle.}, keywords = {dissertation, dissertations, plant, snakeweed, plant, Xanthocephalum, toxicity, seed, germination, seedling establishment, snakeweed, SEE Xanthocephalum, theses, thesis, toxicity, snakeweed, Xanthocephalum, Xanthocephalum, germination}, author = {Jeffcoat, B. Lowell} } @mastersthesis {52155, title = {Thermal ecology of the nocturnal snake, Arizona elegans and the diurnal snake, Masticophis flagellum: Factors influencing activity}, year = {1978}, note = {//NMSU//NONE//}, month = {1978}, pages = {40}, school = {New Mexico State University}, type = {M.S. Thesispp}, address = {Las Cruces, New Mexico}, abstract = {There were significant differences in heat gain between live and dead Masticophis flagellum, but no difference in either heat loss or heat gain in Arizona elegans. Field observations of the daily activity patterns of M. flagellum showed that in habitat with sufficient shade (cover) snakes feed during mid-day but in habitats with sparse shade snakes retired to burrows during mid-day. M. flagellum was a sit-and-wait predator in the shaded environment, and an active-search predator in open habitat. Capture success was greater and handling time shorter in shaded habitat than in open habitat. A. elegans had similar activity patterns and feeding in shaded and sparsely shaded habitats. Feeding in borrows and rodent dens allowed A. elegans to feed on diurnal lizards. Activity patterns of A. elegans in the spring and fall were affected by substrate-air temperature differences.}, keywords = {dissertation, dissertations, snake, Arizona, snake, behavior, snake, Masticophis, snake, thermal ecology, theses, thesis}, author = {Jones, Kenneth Bruce} } @article {52235, title = {Foraging ecology and relative importance of subterranean termites in Chihuahuan desert ecosystem}, journal = {Environmental Entomology}, volume = {4}, number = {1}, year = {1975}, note = {//NMSU//US-IBP//}, month = {1975}, pages = {66-70}, abstract = {

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

}, keywords = {article, articles, decomposition, termites, foraging ecology, termites, journal, journals, termite, foraging ecology}, doi = {10.1093/ee/4.1.66}, url = {files/bibliography/75-EnvironEntom-Whitford.pdf}, author = {Johnson, Kimberly A. and Walter G. Whitford} } @article {52364, title = {Physiological responses to temperature in the patch-nosed snake, Salvadora hexalepis}, journal = {Herpetologica}, volume = {27}, number = {3}, year = {1971}, note = {//NMSU//NONE//}, month = {1971}, pages = {289-295}, abstract = {

Salvadora hexalepis had a mean preferred body temperature in the laboratory of 33.0 C, a mean critical thermal minimum of 7.0 C, and a mean critical thermal maximum of 43.8 C. Oxygen consumption and heart rate increased with temperature, and greatest changes in these parameters at high and low temperature extremes. Cardiac and metabolic responses area what would be predicted for a reptile the size of S. hexalepis. A wide range of thermal tolerance is suggested as an important adaptation for a snake that is primarily a lizard predator.

}, keywords = {article, articles, journal, journals, snake, patch-nosed snake, Salvadora, snake, physiology, snake, Salvadora, physiology}, url = {files/bibliography/71-Herpetologica-Whitford.pdf}, author = {Jacobson, Elliot R. and Walter G. Whitford} } @mastersthesis {JRN54580, title = {Seed Germination in Certain New Mexico Range Grasses}, year = {1928}, month = {04/1928}, pages = {25}, school = {University of Chicago}, abstract = {

Much work has been carried on in recent years in regard to the viability and germination of seeds of various plants. Seed-testing studies are highly important, because the results obtained influence or affect the work of the farmer, the floriculturist, the amateur gardener, and the rancher or ranger. These people cannot afford to plant seeds, expecting a 95 per cent germination and then perhaps having only a 50 per cent germination, due to poor selection of seed, to its immaturity, or to its adulteration with weed seeds. Among the plants studied for germination the grasses have a
prominent part, and this is especially true of the range grasses of the west. It is necessary for the rancher or ranger to know about what percentage of the seeds of the grasses covering his grazing lands he can expect to germinate, since he can then estimate the amount of grazing his lands will tolerate without becoming depleted. He must know whether his grasses propagate themselves vegetatively or by seed, or by both means. Various studies have been made with reference to seed germination, and although they have no direct bearing upon the problem which the writer\  undertook, yet they gave ideas for some tests which were performed after the major problem was completed. The following are short summaries of the work of some of the investigators in the field of seed germination.

}, keywords = {botanical gazette, Jornada Range Reserve Station, Seed germination}, doi = {10.1086/333900}, url = {files/bibliography/1928-1.pdf}, author = {Jackson, Carola V.} } @article {52636, title = {Range and cattle management during drought}, year = {1922}, month = {May 15, 1922}, pages = {84 }, institution = {Government Printing Office}, abstract = {

In the past, cattle production on Southwestern ranges has been a business with \"ups and downs,\" with prosperity or adversity governed by climatic conditions, which brought seasons of plenty in range forage and stock water followed by seasons of restricted forage growth and scarcity of water. Soon after the cattle business became established on the open public range of the Southwest, the herds were built up during a period of good years until the developed ranges were stocked fully or beyond the number they could carry even in good years. Then, at intervals, came dry periods, series of dry years with much less forage produced than was required by the stock on the range and with heavy losses from starvation. During the early days, before all the ranges had been opened up, there was opportunity to develop new range during such emergencies and, thus, to relieve the situation to some extent. Such possibilities diminished more and more, however, as practically all the range came into use. During the drought that ended in 1910, there was little opportunity of this nature and practically none in the drought of 1916 to 1918. The setback to the livestock industry, caused by the combination of unfavorable climatic conditions and unwise range practice, comes about mainly through heavy losses of stock, low calf crop, interference with improvement of breeding herds, retarded growth of young stock and range deterioration. During the last drought (1916 to 1918), according to estimates based on the best data obtainable, losses were at an average rate of 20 per cent annually for the three-year period and reached as high as 35 per cent in 1918, the worst year of the drought. Individual losses were as high as 50 per cent. The large reduction in calf crop is probably next in importance to losses. Natural increase is the main source of income, and if greatly reduced at a time when expenses are high, the result is serious. The calf crop for some of the ranges affected by the last drought was estimated at 35 per cent in 1917, 25 per cent in 1918 and 35 per cent in 1919, the three years most influenced by the drought. These figures are probably not far from representing the true situation. Drought also has been a prime factor in retarding improvement in the grade of stock. Heavy losses and forced sales might wipe out years of effort in building up the herd or reduce the numbers to an extent that culling and selection necessary to maintain quality would not be consistent with the importance of increasing the herd to take advantage of good years; or, the set-back might be such that it left the stockman financially unable to purchase the right kind of bulls.

}, keywords = {cattle management, drought, government publication, range management}, url = {/files/bibliography/008.pdf}, author = {Jardine, J. T. and Forsling, C.L.} } @article {52644, title = {Increase cattle production on southwestern ranges}, year = {1917}, note = {//??//NONE//}, month = {1917}, keywords = {book, books, cattle,productivity, chapter, chapters, production,cattle, report, reports}, isbn = {U.S. Department of Agriculture Bulletin 588}, author = {Jardine, J. T. and Hurtt, L. C.} } @article {52643, title = {Increased cattle production on Southwestern ranges}, year = {1917}, month = {November 15, 191}, pages = {32 }, abstract = {This bulletin presents the results of experiments which bear directly on the problem of how to produce more and better cattle on western range lands, a matter of pressing importance in view of the present need for increasing the Nation{\textquoteright}s food supply.}, keywords = {cattle production, government publication, increased production, Southwestern ranges}, url = {/files/bibliography/005.pdf}, author = {Jardine, J. T. and Hurtt, L. C.} }