@article {JRN55414, title = {Cross-Site comparisons of dryland ecosystem response to climate change in the US Long-Term Ecological Research Network}, journal = {BioScience}, volume = {72}, year = {2022}, month = {8/16/2022}, pages = {889-907}, abstract = {Long-term observations and experiments in diverse drylands reveal how ecosystems and services are responding to climate change. To develop generalities about climate change impacts at dryland sites, we compared broadscale patterns in climate and synthesized primary production responses among the eight terrestrial, nonforested sites of the United States Long-Term Ecological Research (US LTER) Network located in temperate (Southwest and Midwest) and polar (Arctic and Antarctic) regions. All sites experienced warming in recent decades, whereas drought varied regionally with multidecadal phases. Multiple years of wet or dry conditions had larger effects than single years on primary production. Droughts, floods, and wildfires altered resource availability and restructured plant communities, with greater impacts on primary production than warming alone. During severe regional droughts, air pollution from wildfire and dust events peaked. Studies at US LTER drylands over more than 40 years demonstrate reciprocal links and feedbacks among dryland ecosystems, climate-driven disturbance events, and climate change.}, keywords = {ANPP, climate change, disturbance, drought, LTER, wildfire}, doi = {https://doi.org/10.1093/biosci/biab134}, url = {files/bibliography/22-023.pdf}, author = {Amy R Hudson and Debra P C Peters and John M Blair and Daniel L. Childers and Peter T Doran and Kerrie Geil and Micheal Gooseff and Katherine L Gross and Nick Haddad and Melissa A Pastore and Jennifer A Rudgers and Osvaldo Sala and Eric W Seabloom and Gaius Shaver} } @article {JRN55199, title = {Long-term ecological research and evolving frameworks of disturbance ecology}, journal = {BioScience}, volume = {70}, year = {2020}, month = {02/2020}, pages = {141-156}, chapter = {141}, abstract = {Detecting and understanding disturbance is a challenge in ecology that has grown more critical with global environmental change and the emergence of research on social{\textendash}ecological systems. We identify three areas of research need: developing a flexible framework that\  incorporates feedback loops between social and ecological systems, anticipating whether a disturbance will change vulnerability to other environmental drivers,\ and incorporating changes in system sensitivity to disturbance in the face of global changes in environmental drivers. In the present article, we\ review how discoveries from the US Long Term Ecological Research (LTER) Network have influenced theoretical paradigms in disturbance\ ecology, and we refine a framework for describing social{\textendash}ecological disturbance that addresses these three challenges. By operationalizing this\ framework for seven LTER sites spanning distinct biomes, we show how disturbance can maintain or alter ecosystem state, drive spatial patterns\ at landscape scales, influence social{\textendash}ecological interactions, and cause divergent outcomes depending on other environmental changes. }, keywords = {disturbance, ecological research networks, ecological theory, LTER, social{\textendash}ecological studies}, doi = {10.1093/biosci/biz162}, url = {files/bibliography/20-009.pdf}, author = {Gaiser, Evelyn E. and Bell, David M. and Max Castoroni and Daniel L. Childers and Peter M. Groffman and Rhett G. Jackson and Kominoski, John S. and Debra C. Peters and Steward T.A. Pickett and Ripplinger, Julie and Zinnert, Julie C.} } @article {JRN54650, title = {Nematode exclusion and recovery in experimental soil microcosms}, journal = {Soil Biology and Biochemistry}, volume = {108}, year = {2017}, pages = {78-83}, abstract = {

Experimental manipulations of soil fauna are a powerful tool for assessing causal relationships between belowground biodiversity and key ecosystem properties. However, preparing soil microcosm treatments without soil fauna for ecological experiments can be problematic. Methods to exclude nematodes, a ubiquitous and functionally important component of terrestrial ecosystems, have been developed for a few specific ecosystems, some of them involving the application of nematicides that may have interactive effects throughout the soil food web. Our goal was to develop a method to remove nematodes from soils of three Long Term Ecological Research (LTER) grassland sites, ranging from desert to moist, without use of chemicals and with moderate disturbance. Moreover, we aimed at testing whether the nematode removal would remain effective up to several weeks later. The following treatments were applied to ~3- kg soil microcosms in the laboratory: (1) a 72 h heating (65 C) - freezing (-20 C) - heating (65 C) cycle using soil maintained at its original water content, and pre-wetting soil 24 h before heating (65 C) for either (2A) 48 h or (2B) 24 h.We measured treatment effects on total abundance and trophic structure of the nematode community. To investigate whether nematodes would recolonize eight weeks after treatments, we conducted a greenhouse experiment where individual seedlings of the dominant grass species for each ecosystem were transplanted to treated and non-treated (control) soils. A heat-freezeheat cycle of 72 h using soil in its original field water content killed 60, 95, and 99\% of the nematodes for the desert, semi-arid, and moist tallgrass prairie soils, respectively. Pre-wetting soil before heating increased mortality to 99\% for all ecosystems after only 24 h at 65 C. Root-feeders were the most resistant nematode trophic group. Eight weeks after treatments, there was no significant nematode recolonization for the pre-wetted 48 h heated soils from the three sites, while for the semi-arid and moist sites there was a slight recovery in abundance in soil from the 24 h heating treatment. Therefore, a treatment at 65 C for 48 h using pre-wetted soil is recommended for eight-week long manipulative experiments in order to assure the effectiveness of the nematode removal throughout the experiment. {\textcopyright} 2017 Elsevier Ltd. All rights reserved.

}, keywords = {grasslands, intersite, LTER, nematode removal, soil defaunation, soil microcosm}, doi = {10.1016/j.soilbio.2017.02.001}, url = {files/bibliography/JRN00658.pdf}, author = {A. C. Franco and Knox, Matthew A. and Andriuzzi, Walter S. and Cecilia M. de Tomasel} } @conference {50115, title = {EcoTrends: Learning how to support synthetic research through innovative solutions}, booktitle = {LTER All Scientists Meeting}, year = {2009}, month = {09/11/2009}, address = {Estes Park, Colorado}, abstract = {The EcoTrends project is an LTER network-level synthesis program geared toward making long-term ecological data highly explorable, accessible and comparable for cross-site synthesis research. Five years of working with 50 sites (LTER, USDA ARS, USFS, and other agencies) have offered many lessons that can be utilized as we strive to improve and upgrade EcoTrends services. Here, we describe the project{\textquoteright}s goals and products, discuss lessons learned, and lay out plans for a future system that will better serve the ecological research and information management community.}, keywords = {cross-site, EcoTrends, LTER}, author = {C. Laney and Debra C. Peters} } @conference {50133, title = {Shifts in species dominance at a biome transition zone: Importance of asymmetric competition to long-term trends}, booktitle = {2009 LTER All Scientist Meeting}, year = {2009}, abstract = {Landscapes at the Sevilleta LTER site are dominated or codominated by two perennial grasses from different biomes, Bouteloua eriopoda (black grama) from the Chihuahuan Desert and B. gracilis (blue grama) from the shortgrass steppe, and the Chihuahuan Desert shrub Larrea tridentata (creosotebush). We used a long-term removal study to examine inter-specific interactions between these dominant species, and to determine which species would eventually dominate following the removal of the others. Plants of the dominant species were removed from 5 3m x 4m plots in 1995 at five sites that were either dominated by one of the three species (blue grama grasslands, black grama grasslands, cresootebush shrublands) or at ecotones codominated by two species (blue grama/black grama; black grama/creosotebush). Plant cover is estimated annually, and removals have been conducted annually since that time. Results show that removal of black grama has little effect on cover of blue grama whereas removal of blue grama or creosotebush results in marked increases in cover of black grama. Our results show that competition between black grama and either blue grama or creosotebush is asymmetric. These interactions suggest that black grama dominance may be reduced in the future under climate conditions that favor growth of either blue grama or creosotebush since these species can outcompete black grama. Landscape patterns associated with soil texture can also be explained by these interspecific interactions for soil water in this semiarid environment.}, keywords = {asymmetric, B. gracilis, black grama, Bouteloua eriopoda, creosotebush, LTER, Sevilleta}, author = {Debra C. Peters and Jin Yao} } @inbook {50420, title = {A Holistic View of an Arid Ecosystem: A Synthesis of Research and Its Applications}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {354-368}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {17}, address = {New York}, abstract = {A primary objective of the Jornada Long-Term Ecological Research (LTER) program has been to provide a broad view of desert grassland ecology. Early architects of the LTER program felt that existing ecological datasets were usually of too short a duration and represented too few ecosystem components to provide a foundation for predicting dynamics in response to disturbances (NSF 1979). This recognition gave rise to the LTER approach{\textemdash}using long-term and multidisciplinary research at particular places to advance a holistic and broad-scale, but also mechanistic, view of ecological dynamics. Such a view is essential to applying ecological research to natural resources management (Golley 1993; Li 2000). In this synthesis chapter we ask: What has this approach taught us about the structure and function of a desert grassland ecosystem? How should this knowledge change the way we manage arid ecosystems? What gaps in our knowledge still exist and why?}, keywords = {Chihuahuan Desert, desert grassland ecosystem, holistic view, Jornada Basin, LTER, multidisciplinary, patch-based correlations, research, synthesis book}, url = {/files/bibliography/06-068.pdf}, author = {Brandon T Bestelmeyer and Joel R. Brown and Kris Havstad and E.L. Fredrickson}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @conference {50421, title = {How can LTER data contribute to ecosystem management}, booktitle = {LTER All Scientists Meeting}, year = {2006}, month = {September 21, 20}, pages = {Paper No. 35}, address = {Estes Park, CO}, abstract = {Research conducted at LTER sites has great potential for use by natural resource managers and policymakers within the surrounding regions, but in many cases the link between LTER data and management policy is limited. We use examples from the Jornada Basin LTER to illustrate some general steps and research questions that can connect LTER research to whole-ecosystem management (e.g., the Bureau of Land Management, Forest Service, ranchers). The steps/questions include 1) what are spatial extents, often defined by climate and physiography, within which ecological patterns and processes are similar, 2) what are the key gradients and thresholds in soil and climate within regions governing ecological processes, 3) what is the distribution of potential and alternative ecosystem states along the gradients, 4) what are the mechanisms of transition among states, 5) what patterns and tools can be used to recognize and map states within the region, and 6) how should recognition of states be used to generate management decisions?}, keywords = {ecosystem, LTER, management}, author = {Brandon T Bestelmeyer and Caitriana Steele and Jeffrey E. Herrick and Curtis H. Monger} } @inbook {50451, title = {Grazing Livestock Management in an Arid Environment}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {266-277}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {13}, address = {New York}, abstract = {The history of livestock grazing in the Jornada Basin of southern New Mexico is a relatively recent story, but one of profound implications. For four centuries this region has supported a rangeland livestock industry, initially sheep, goats, and cattle, but primarily beef cattle for the past 130 years. Throughout this brief history of a domesticated ruminant in an ecosystem without a significant presence of large hoofed mammals as part of its evolutionary development, the livestock industry has continually grappled with high degrees of temporal and spatial variation in forage production. Management of this consumptive use, whether during Spanish, Mexican, United States Territorial, United States federal, or New Mexican governments, has constantly reaffirmed the need for grazing management to be flexible and responsive to the stress of droughts. The history of anecdotal experiences has been more recently augmented by scientific investigations first initiated in 1915. This chapter outlines the general history of livestock in this region, the historical specifics of ranching in the Jornada Basin, and resulting principles of grazing management derived from nearly a century of studies on grazing by large, domesticated herbivores.}, keywords = {Chihuahuan Desert, grazing, Jornada Basin, livestock management, LTER, synthesis book}, url = {/files/bibliography/06-064.pdf}, author = {Kris Havstad and E.L. Fredrickson and L. Huenneke}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @inbook {50448, title = {Introduction}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {3-14}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {1}, address = {New York, NY}, abstract = {Arid lands throughout the world, including lands at the border of arid regions, are increasingly subject to human impact, leading to degradation of soils, losses of plant production, and a diminished economic potential to support human populations. Focusing on the human impact and consequent losses in economic potential, we often call these changes \"desertification.\" With the potential for global climate change, however, the definition of desertification and its potential must be expanded. Indeed, the 1992 United Nations\’ Desertification Convention defined desertification as \"land degradation in arid, semiarid and dry subhumid areas resulting from various factors, including climatic variations and human activities.\" It is more recently recognized that desertification involves human and environmental drivers but is a symptom evident at regional spatial scales that emerges from degradation at finer spatial scales. Assertions relative to an updated and revised paradigm regarding desertification have been developed. In l981, a group of scientists based in Las Cruces, New Mexico, and associated with New Mexico State University proposed a program of long-term ecological research in the Jornada Basin of southern New Mexico (USA) to gain a better understanding of processes that determine the structure and function of desert ecosystems. To an extent, this book represents both a synthesis of that effort and a benchmark of our progress over the last 23 years. In addition, this book draws on a longer history of research in the Jornada Basin that dates back to the early part of the twentieth century. Both the group and its mission have evolved since 1981, but an initial motivation for our studies was the dramatic, historic records of vegetation change in the Jornada.}, keywords = {Chihuahuan Desert, introduction, Jornada Basin, LTER, synthesis book}, url = {/files/bibliography/06-052.pdf}, author = {Kris Havstad and W. H. Schlesinger}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @booklet {50450, title = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {492}, publisher = {Oxford University Press}, address = {New York, NY}, abstract = {

This book is a synthesis of the arid rangeland research conducted in southern New Mexico for nearly a century. The Jornada Basin is truly a long-term research site, and this history is reflected in the databases described in many of the chapters in this book. Research in this basin formally began in 1912 with the creation by Presidential Order within the US Department of Agriculture of the 77,000-ha Jornada Range Reserve. Early publications, primarily USDA bulletins or journal articles in Ecology and the Botanical Gazette, appeared in print beginning in 1917. Researchers such as C.L. Forsling, J.T. Jardine, R.S. Campbell, and R.H. Canfield authored many of these early works, which are both classics in rangeland management and part of the foundation of studies decades later. The creation in 1927 of the Chihuahuan Desert Rangeland Research Center (initially known as the College Ranch) under the jurisdiction of New Mexico State University on 24,000 ha adjacent to the Jornada Range established the 101,000-ha area for long-term research in the basin that operates today. This history of research during the early twentieth century had numerous themes. Much of the early emphasis was on management related to agricultural production. Many of the principles that have been developed about livestock grazing management and rangeland improvement practices in the southwestern US and for arid lands in general can be traced to studies in the Jornada Basin. Yet, during these earlier decades there were also classic papers published on vegetation dynamics, resource redistribution, and small-mammal ecology. Over 40 years ago the first interdisciplinary studies were initiated; these studies served as a forerunner for the collaborative studies of the International Biological Programme (IBP) of the 1970s and those of the Jornada Basin that continue today. This 18-chapter book concludes with a description of future research for important issues in the twenty-first century

}, keywords = {Chihuahuan Desert, ecosystem, Jornada Basin, LTER, synthesis book}, url = {files/bibliography/JRN00461.pdf}, author = {Kris Havstad and L. Huenneke and W. H. Schlesinger}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @inbook {50459, title = {Remediation Research in the Jornada Basin: Past and Future}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {278-304}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {14 }, address = {New York, NY}, abstract = {Land degradation in most of the Chihuahuan Desert is characterized by a shift from grass- to shrub-dominated plant communities. Consequently, most remediation efforts are focused on grassland restoration. Early experiments and trials focused on grazing management. Beginning in the 1930{\textquoteright}s and continuing through the 1980{\textquoteright}s, various methods of shrub control were evaluated. Early investigators had an intuitive and practical understanding of the system in which they worked. They saw the individual limitations to grassland recovery and attempted to address them. In order to be more successful than they were, we must begin to work at spatial and temporal scales relevant to the processes we hope to affect and target our interventions to those locations and during those periods when the processes are most susceptible to change. We must also, as the earlier workers did, simultaneously target multiple processes with the objective of increasing the resistance and resilience of the modified ecosystems.}, keywords = {Chihuahuan Desert, Jornada Basin, LTER, synthesis book}, url = {/files/bibliography/06-065.pdf}, author = {Jeffrey E. Herrick and Kris Havstad and A. Rango}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @inbook {50490, title = {Future Directions in Jornada Research: Applying an Interactive Landscape Model to Solve Problems}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {369-386}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {18}, address = {New York, NY}, abstract = {In this book chapter, we propose a new model of arid and semiarid landscapes that focuses explicitly on the processes and properties that generate spatial variation in ecosystem dynamics. We are specifically interested in three interrelated aspects of landscapes: (1) feedbacks among plants, animals, and soils generated from interactions among biotic processes, a heterogeneous physical template, and the disturbance regime across a range of spatial and temporal scales, (2) neighborhood or contagious processes that generate fluxes and flows within and among spatial units, and (3) the landscape context and the condition of the study area of interest relative to its surroundings that modifies the transfers of materials. We first describe our spatially interactive model and compare it to previous models then introduce an approach to identify the landscape locations where spatial processes and information are needed in order to understand and predict ecosystem dynamics. The local, regional, and global implications of our interactive landscape model are also discussed.}, keywords = {Chihuahuan Desert, Jornada Basin, LTER, synthesis book}, url = {/files/bibliography/06-069.pdf}, author = {Debra C. Peters and W. H. Schlesinger and Jeffrey E. Herrick and L. Huenneke and Kris Havstad}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @inbook {50487, title = {Plant Communities in the Jornada Basin: The Dynamic Landscape}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {211-231}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {10}, address = {New York, NY}, abstract = {Plant communities of the Jornada Basin LTER are characteristic of the northern Chihuahuan Desert, both in structure and dynamics. Five major vegetation types are often distinguished that differ in plant species cover and composition, as well as other factors, such as animal populations, soil properties, and elevation. Similar to many other parts of the Chihuahuan Desert, these plant communities have experienced major shifts in vegetation over the past 50-150 years. The most dramatic changes in vegetation have occurred as a result of woody plant encroachment into perennial grasslands. In this chapter, we describe the characteristics of each vegetation type and the documented changes in each type at the Jornada. We also discuss the key drivers (small and larger animal activity, drought, fire, and directional changes in climate) influencing these vegetation dynamics.}, keywords = {Chihuahuan Desert, Jornada Basin, LTER, synthesis book}, url = {/files/bibliography/06-061.pdf}, author = {Debra C. Peters and Gibbens, Robert P.}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @inbook {50507, title = {Patterns and Controls of Soil Water in the Jornada Basin}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {107-132}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {5}, address = {New York, NY}, abstract = {This chapter focuses on the controls and patterns of soil moisture in the Jornada Basin. First, we describe general properties that commonly contribute to soil water heterogeneity; secondly, we offer a brief overview of soil water research in the Jornada Basin; and lastly, we describe specific patterns of soil water content and availability observed in the Jornada Basin. Our goal is to describe general patterns of soil water that are likely to occur across the Chihuahuan Desert region.}, keywords = {Chihuahuan Desert, Jornada Basin, LTER, synthesis book}, url = {/files/bibliography/06-056.pdf}, author = {K. A. Snyder and K. A. Mitchell and Jeffrey E. Herrick}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @inbook {50522, title = {Chihuahuan Desert Fauna: Effects on Ecosystem Properties and Processes}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {247-265}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {12}, address = {New York, NY}, abstract = {This chapter addresses the direct and indirect effects of animals on ecosystem processes and/or their effects on ecosystem properties. This has been the primary focus of animal studies on the Jornada Experimental Range (JER) and the Chihuahuan Desert Rangeland Research Center (CDRRC) during the twentieth century. Early studies dealt with animal species that were thought to reduce the amount of primary production that was available to support livestock. With the establishment of the International Biological Programme (IBP) in the late 1960s and its premise that ecosystems could be modeled based on the energy flow conceptual model, animal studies were designed to measure energy flow through consumer populations. Those studies yielded estimates of consumption of live plant biomass between 1 and 10\% of the annual net primary production. It was concluded that, in most ecosystems, consumers process only a small fraction of the net primary production as live plant material and consumers play important roles in ecosystems as regulators of ecosystem processes and a less important role in energy flow. This hypothesis has been the focus of animal studies in the Jornada Basin for nearly 30 years. Studies of animals as regulators of ecosystem processes led to the expansion of this hypothesis to include the effects of animals on ecosystem properties. Expanding the spatial scale of studies from the patch to the watershed and landscape engendered hypotheses that animals have an effect on processes at those scales because of animal activities that affect redistribution of soil and organic matter.}, keywords = {Chihuahuan Desert, Jornada Basin, LTER, synthesis book}, url = {/files/bibliography/06-063.pdf}, author = {Walter G. Whitford and Brandon T Bestelmeyer}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @article {50641, title = {Scale dependence in the species-richness-productivity relationship: the role of species turnover}, journal = {Ecology}, volume = {85}, number = {10}, year = {2004}, note = {//NMSU,USDA//LTER IV//Entered 11/14/2006.}, month = {2004}, pages = {2701-2708}, abstract = {

Recent research in aquatic systems suggests that productivity{\textendash}richness relationships change with spatial scale and that species turnover (i.e., spatial and temporal variation in species composition) plays an important role in generating this scale dependence. The generality of such scale dependence and the effects of variation in temporal scale remain unknown. We examined the extent to which the richness{\textendash}productivity relationship in terrestrial plant communities depends on spatial or temporal scale and evaluated how spatial and temporal turnover (i.e., species turnover in space and time) generates scale dependence in these relationships using data from two Long-Term Ecological Research (LTER) sites (Jornada and Konza). We found a weak hump-shaped relationship (Jornada) and no relationship (Konza) between richness and productivity at the smallest focal scale (1 m2 at Jornada and 50 m2 at Konza) at each site, but strong hump-shaped relationships at the largest focal scale (49 m2 at Jornada and 200 m2 at Konza) for each site. Relationships between spatial turnover and productivity at each site mirrored the productivity{\textendash}richness relationships that emerged at the larger spatial scale (i.e., a significant hump-shaped pattern). In contrast, temporal turnover was unrelated to productivity, and hence increasing temporal scale did not appreciably change the form of the productivity{\textendash}richness relationship. Our study suggests that the way in which productivity{\textendash}richness relationships change with spatial or temporal scale depends on the form and strength of the underlying relationship between species turnover and productivity. Moreover, we contend that a dominant effect of increasing productivity is the generation of dissimilarity in species composition among localities that comprise a region, rather than increasing the number of species that occur within local communities. Thus, understanding the mechanisms that cause species turnover to vary with productivity is critical to understanding scale dependence in richness{\textendash}productivity relationships.

}, keywords = {article, biodiversity, environmental heterogeneity, grasslands, journal, LTER, productivity, scale, species composition, species richness, species turnover, stability, terrestrial plants}, doi = {10.1890/03-0561}, url = {files/bibliography/JRN00418.pdf}, author = {Chalcraft, David R. and John W. Williams and M. D. Smith and Michael R. Willig} } @conference {51085, title = {Jornada Basin LTER: Linkages in semiarid landscapes}, booktitle = {85th Annual Meeting, Ecological Society of America}, year = {2000}, month = {August 8-10, 200}, pages = {Abstract p. 396}, address = {Snowbird, UT}, abstract = {Chihuahuan Desert landscapes exemplify the ecological conditions, vulnerability, and management issues found in semiarid regions around the globe. The goal of the JRN-LTER program is to identify the key factors controlling ecosystem dynamics in semiarid landscapes with the objective of understanding the causes and consequences of desertification. Previous work has focused primarily at the scale of a single plant-interspace and the redistribution of resources at that scale. Our central hypothesis for LTER IV is that landscape position and linkages among landscape units exert important influences on ecosystem dynamics and biotic patterns. We propose to build upon our understanding of resource redistribution at the plant-interspace scale in several ways. We will synthesize existing long-term data with new studies on linkages among landscape units. We will conduct simulation model analyses to test the relative importance of within- versus between-unit processes. We will initiate studies of landscape fluxes of water, nutrients, and organisms to evaluate key processes affecting ecosystem dynamics at this scale. We will also employ remote sensing to assess fluxes and processes at larger spatial scales. Cross-site studies will be used to test the generality of our hypotheses for application to management and remediation of semiarid ecosystems and desertified landscapes.}, keywords = {desertification, ecosystem dynamics, LTER, remote sensing, semiarid, simulation model}, author = {L. Huenneke and Kris Havstad and Jeffrey E. Herrick and David C. Lightfoot and Curtis H. Monger and Debra C. Peters and A. Rango} } @conference {51105, title = {Cross-site comparisons of climate and vegetation for two semiarid grasslands and their ECOTONE}, booktitle = {85th Annual Meeting, Ecological Society of America}, year = {2000}, month = {August 6-10, 200}, pages = {372}, address = {Snowbird, UT}, abstract = {The objective of this ongoing work is to compare ecosystem characteristics of three LTER grassland sites located along a north-south aridity gradient. These sites share some characteristics and differ in others that are expected to be important to their ability to respond to environmental drivers, including climate change and land use. The SGS-LTER in northern Colorado is representative of the shortgrass steppe and is dominated by th long-lived bunchgrass, Bouteloua gracilis (blue grama). Grasslands at the JER-LTER in southern New Mexico are dominated by the short-lived stoloniferous grass, Bouteloua eriopoda (black grama). Landscapes at the SEV-LTER in central New Mexico consist of patches that are dominated or codominated by these two species. Regional analyses of the climate and simulated recruitment showed important differences between biomes that may account, at least in part, for observed patterns in dominance and species diversity. Field studies of seed production and seed storage in the soil, as well as simulation analyses, showed the responses of these species at their ecotone are not predictable based on responses within the biomes where they dominate.}, keywords = {characteristics, ecosystem, grassland, LTER}, author = {Debra C. Peters} }