@proceedings {JRN55398, title = {Ecological science infrastructure for sustainability transformations in rangelands}, year = {2022}, month = {1/28/2022}, abstract = {Sustainability transformations{\textemdash}deliberate and radical shifts in values, governance, and management regimes to achieve sustainability{\textemdash}are needed in rangelands as in other components of the Earth system. We review four concepts comprising an ecological science infrastructure to support such transformations. The foundation is standard measurement of rangeland conditions in the field, especially vegetation and soil properties that underpin the environmental aspects of sustainability. Big data resources, especially gridded spatial datasets produced by models and remote sensing, can be combined with field data and computational approaches to upscale information about rangeland conditions and produce additional indicators of ecosystem functions and services. State and transition models (STMs) linked to land types provide a means to interpret indicators and link interpretations to sustainable land management practices to manage change. Technologies for climate adaptation in rangelands also need to be linked to STM databases. Web and mobile technologies can put multifaceted science knowledge into the hands of pastoralists worldwide to support transformational changes in how rangelands are managed.}, author = {Brandon T Bestelmeyer and Jeffrey E. Herrick and Joel R. Brown and Dawn M. Browning and Bulgamaa Densambuu and Emile H. Elias and Sarah McCord and H. Raul Peinetti and S. Spiegal and Nicholas Webb and Jebediah C. Williamson} } @conference {JRN55350, title = {An extreme precipitation event, abrupt grass recovery, and soil processes in the Chihuahuan Desert}, booktitle = {Ecological Society of America (ESA)}, year = {2022}, month = {07/11/2022}, abstract = {Landscapes in the northern Chihuahuan Desert have been undergoing a gradual shift from perennial grassland to shrubland over the past century, driven primarily by the legacies of historical disturbance events and ongoing aridification. Nonetheless, extreme high rainfall periods can result in instances of remarkable grassland recovery, although they are highly patchy. In one area on the USDA-ARS Jornada Experimental Range, abrupt grass recovery occurred in an eroding Prosopis glandulosa shrubland state in response to a high rainfall period (2007-2009){\textemdash}an event that we did not imagine could happen. We are comparing ecosystem processes in this {\textquotedblleft}recovered savanna{\textquotedblright} to 1) patches of grassland that are in a relatively unaltered {\textquotedblleft}reference{\textquotedblright} state and 2) patches of shrubland state in which grass recovery did not occur. We asked a) is the recovered savanna similar to the reference grassland with respect to structure, composition, and vegetation-soil feedbacks and b) what led to spatial variation in grassland recovery? We compared vegetation and soil chemical and physical properties at twelve replicate study plots in each of the three states: recovered savanna, reference grassland, and shrubland. In addition, we are monitoring soil volumetric water content and aeolian sediment flux within each state. ~ We found that although the species composition of grasses differed strongly between reference grassland and recovered savanna, ecosystem functions measured were largely similar between these states but differed from shrubland states. Infiltration rate, soil aggregate stability, soil organic carbon, and soil C:N ratio were typically similar between reference grassland and recovered savanna but often far higher than in shrubland. Large bare gaps between plant canopies in the shrubland enabled far higher aeolian sediment fluxes than in the reference grassland and recovered savanna where bare gap connectivity was smaller. Static (edaphic) soil properties and volumetric water content in recovered savanna were intermediate between reference grassland and shrubland, suggesting that sites experiencing grass recovery may have been predisposed to grass establishment by virtue of their topoedaphic settings, yet were not resilient enough to avoid grass loss in the first place. The recovered savannas persist after a decade (including extreme dry years), provide ecosystem services comparable to the reference grasslands that originally occupied these sites, and are superior to the shrublands that they recently replaced. The question before us now is how to encourage more shrubland to savanna transitions.}, keywords = {abrupt grass recovery, Chihuahuan Desert, extreme precipitation event, soil, soil processes}, author = {Brandon T Bestelmeyer and Matthew Levi and Neeshia Macanowicz and Heather L. Throop and Nicholas Webb} } @article {JRN55278, title = {Assessing sustainability goals using big data: Collaborative adaptive management in the Malpai borderlands}, journal = {Rangeland Ecology \& Management}, volume = {77}, year = {2021}, month = {07/2021}, pages = {17-29}, chapter = {17}, abstract = {Collaborative adaptive management is a means to achieve social and ecological goals in complex natural resource management settings. Evaluation of collaborative management outcomes, however, is difficult at the scale of large landscapes. We developed an approach for such evaluations using long-term, spatiotemporal gridded or county-level datasets alongside local information on changes in ranch ownership. We applied this approach to evaluate the sustainability goals of the Malpai Borderlands Group (MBG) by comparing the MBG landscape to surrounding, similar desert grassland landscapes. We matched datasets, where possible, to management goals, including the preservation of ranching livelihoods, prevention of rangeland fragmentation by exurban development, sustaining the ecological role of fire, limiting or reversing woody plant encroachment into grasslands, sustaining rangeland productivity, and sustaining biodiversity. We found that the number of ranch families changed little since MBG was established, although several ranches were consolidated within some families or absentee owners, such that multiple families share other ranches. The number of beef cattle ranches declined within one MBG county, likely due to increasing depth to groundwater. Exurban development and rangeland-to-cropland conversion have been virtually nonexistent in the MBG landscape, while such conversions are common in adjacent landscapes. Coordinated fire planning with low fragmentation of rangeland has led to extensive fires in the MBG landscape, dwarfing the area burned in adjacent landscapes. The percent of land area exhibiting significant trends of increasing bare ground cover was intermediate in the MBG landscape compared with adjacent landscapes, while herbaceous and shrub cover exhibited significant trends in only a small fraction of the study region. Rangeland productivity exhibited significant declines in some landscapes, but declines were minimal in the MBG area. Our analysis suggests that collaborative adaptive management implemented by the MBG has aligned with their goals, but changing climate, water availability, and demography will become increasingly challenging.}, keywords = {big data, fire, plant production, ranch turnover, rangeland-cropland conversion, sustainability}, doi = {https://doi.org/10.1016/j.rama.2021.03.002}, url = {files/bibliography/21-012.pdf}, author = {Brandon T Bestelmeyer and S. Spiegal and Winkler, Rich and D. K. James and Matthew Levi and Jebediah C. Williamson} } @conference {JRN55404, title = {Ecological transformations in desert grasslands: resist, accept, or direct?}, booktitle = {Society for Range Management Meeting Abstracts}, year = {2021}, month = {12/05/2021}, abstract = {The transformation of many rangeland ecosystems is inevitable, necessitating new frameworks to guide management decisions. We describe ongoing transformation in desert grasslands of southwestern New Mexico using century-long vegetation monitoring and climate datasets from the Jornada Experimental Range and monitoring of recent restoration actions. These datasets indicate undesirable, irreversible changes from historical benchmarks but include some potentially desirable outcomes. We use these datasets to consider management decisions via the resist-accept-direct (RAD) framework. Considering directional changes in climate and ecological thresholds, managers can respond to the trajectory of change by resisting (working to maintain or restore based upon historical or acceptable current ecosystem conditions), accepting (allowing an ecosystem to change without intervening), or directing (actively shaping ecosystem change toward preferred new conditions). We describe a logic for RAD decisions in rangeland management and restoration based on a consideration of climate and ecological processes.}, author = {Brandon T Bestelmeyer and Erica M. Christensen and Laura M. Burkett and Matthew Levi and Leticia Lister and Neeshia Macanowicz and Nicholas Webb} } @article {JRN55287, title = {Effects of managed fire on a swale grassland in the Chihuahuan Desert}, journal = {Rangelands}, year = {2021}, month = {07/27/2021}, pages = {1-4}, abstract = {On the Ground {\textbullet} Fire is considered a critical process for limiting shrub encroachment and maintaining grassland structure and functions. {\textbullet} Fire can be detrimental to grasses in upland settings of arid desert grasslands, but no studies have been performed in more productive swale grasslands. {\textbullet} Monitoring of a prescribed fire treatment in a swale grassland in southern New Mexico indicated that perennial grasses had not recovered after 5 years, even with above-average rainfall. Furthermore, indicators of erosion susceptibility increased, and shrubs resprouted rapidly.}, keywords = {ecological site descriptions, prescribed fire, state and transition models, vegetation monitoring}, doi = {10.1016/j.rala.2021.05.001}, url = {files/bibliography/21-022.pdf}, author = {Brandon T Bestelmeyer and Laura M. Burkett and Leticia Lister} } @inbook {JRN55317, title = {State-and-transition modelling}, booktitle = {The Routledge Handbook of Research Methods for Social-Ecological Systems}, year = {2021}, pages = {371-382}, chapter = {27}, abstract = {Chapter 27 considers state-and-transition models (STMs), which are tools to explain the causes and consequences of ecosystem change. The chapter discusses general types of STMs, including conceptual STMs, spatial and non-spatial state-and-transition simulation models, process-based STMs and ecosystem service-based STMs. It goes on to discuss the types of social-ecological systems (SES) problems and research questions commonly addressed by this set of methods, as well as their limitations, resource implications and new emerging research directions. The chapter also includes an in-depth case study showcasing the application of STMs, and suggested further readings on these methods.}, keywords = {State-and-transition modelling}, isbn = {9781003021339}, doi = {10.4324/9781003021339-32}, url = {files/bibliography/21-032.pdf}, author = {Brandon T Bestelmeyer and Maria Fern{\'a}ndez-Gim{\'e}nez and Bulgamaa Densambuu and Retta Bruegger} } @conference {JRN55248, title = {Big data, local science: Not an oxymoron}, booktitle = {Ecological Society of America}, year = {2020}, month = {08/2020}, address = {Virtual Conference}, abstract = {Collaborative natural resource management (CNRM) projects are increasingly a common approach to link science to decision-making in rangelands, forests, and fisheries. Such approaches emphasize interactions among scientists from a variety of disciplines with stakeholders to manage adaptively. The availability of human and data resources, however, limit the initiation of CNRM projects and their benefits to stakeholders and ecosystems. We propose a {\textquotedblleft}big data{\textquotedblright} framework for catalyzing and supporting CNRM projects based on standardized monitoring, open access databases, gridded spatial data products, data-model integration, and mobile applications. Results/Conclusions We provide examples of information products used to support local decision-making from desert grassland areas of the Southwestern U.S. used for livestock production and that are experiencing widespread shrub encroachment. Products include 1) long-term evaluations of vegetation and wind erosion responses to shrub control using standard monitoring methods coupled to models and gridded spatial data and 2) remote sensing-based analyses of long-term trends in vegetation composition and forage production at 30m and 4 km resolutions, respectively, used to provide region-scale environmental context for a collaborative landscape management effort. A unified big data framework has yet to be fully developed, but its creation could help scale up CNRM activities that will be essential to promoting human well-being and conserving biodiversity. Poster $\#$81832.}, author = {Brandon T Bestelmeyer and Sarah McCord and Nicholas Webb and Joel R. Brown and Jeffrey E. Herrick and Debra C. Peters} } @article {JRN55237, title = {Scaling up agricultural research with artificial intelligence}, journal = {IEEE IT Professional}, volume = {22}, year = {2020}, pages = {32-38}, type = {05/2020}, chapter = {32}, abstract = {Agricultural systems are enormously variable in space and time. New and developing artificial intelligence (AI)-based tools can leverage site-based science and big data to help farmers and land managers make site-specific decisions. These tools are improving information about soils and vegetation that forms the basis for investments in management actions, provides early warning of pest and disease outbreaks, and facilitates the selection of sustainable cropland management practices. Continued progress with AI will require more observational data across a wide range of agricultural settings, over long time periods.}, issn = {1520-9202}, doi = {10.1109/MITP.2020.2986062}, url = {files/bibliography/20-023.pdf}, author = {Brandon T Bestelmeyer and Marcillo, Guillermo and Sarah McCord and Steven Mirsky and G. E. Moglen and Neven, Lisa and Debra C. Peters and Sohoulande Djebou, Dagbegnon and Wakie, Tewodros} } @article {JRN55170, title = {Collaborative Approaches to Strengthen the Role of Science in Rangeland Conservation}, journal = {Rangelands}, volume = {41}, year = {2019}, month = {October 2019}, pages = {218-226}, abstract = {The use of science to inform conservation practices is limited by broad generalities generated from limited sampling alongside narrow ecosystem service perspectives. Collaborative science approaches featuring {\textquotedblleft}social-ecological system{\textquotedblright} perspectives are being used as a means to improve the utility of science. We review our approach to collaborative science to improve brush management outcomes in rangelands in the Chihuahuan Desert. Expanding the use and utility of collaborative science requires stable support via targeted funding and technical expertise, as well as web-based tools and mobile applications that link specific locations to science information and conservation practice guidelines.}, keywords = {brush management, Collaborative adaptive management, ecological sites, monitoring, State transition models}, doi = {10.1016/j.rala.2019.08.001}, url = {files/bibliography/19-028.pdf}, author = {Brandon T Bestelmeyer and Laura M. Burkett and Leticia Lister and Joel R. Brown and Robert L. Schooley} } @article {JRN55253, title = {Twenty-five years and a wiser science}, year = {2019}, month = {11/2019}, pages = {Page 3}, abstract = {Scientists are now better equipped than ever to help unify communities and chart solutions to changing climate, aging ranchers, globalization, new technologies, and changing values. As we work on the next 25 years, we should be prepared to learn how much we have yet to understand about Nature, one another, and ourselves.}, author = {Brandon T Bestelmeyer} } @article {JRN54925, title = {The Grassland{\textendash}Shrubland Regime Shift in the Southwestern United States: Misconceptions and Their Implications for Management}, journal = {Bioscience}, volume = {68}, year = {2018}, month = {09/2018}, pages = {678-690}, chapter = {678}, abstract = {

Transitions from semiarid grassland to shrubland states are among the most widely recognized examples of regime shifts in terrestrial ecosystems. Nonetheless, the processes causing grassland{\textendash}shrubland transitions and their consequences are incompletely understood. We challenge several misconceptions about these transitions in desert grasslands, including that (a) they are currently controlled by local livestock grazing and drought events, (b) they represent severe land degradation, and (c) restoration of grassland states is impossible. Grassland{\textendash}shrubland transitions are the products of multiple drivers and feedback systems, both ecological and social, interacting at multiple scales of space and time. Grass recovery within shrubland states{\textemdash}with and without shrub removal{\textemdash}produces novel ecosystems that are dissimilar from historical grasslands but that provide important ecosystem services. Projected increases in climate variability are likely to promote the further displacement of perennial grasses by xerophytic shrubs. This article offers guidelines for managing grassland{\textendash}shrubland transitions in the face of changing biophysical and socioeconomic circumstances.

}, keywords = {long term data, novel ecosystems, restoration, social-ecological, state transition, threshold}, doi = {doi.org/10.1093/biosci/biy065}, url = {files/bibliography/18-016.pdf}, author = {Brandon T Bestelmeyer and Debra C. Peters and Steven R. Archer and Dawn M. Browning and Gregory S. Okin and Robert L. Schooley and Nicholas Webb} } @conference {JRN54913, title = {A Tale of Two Thresholds: Mistakes and Serendipity in a Desert Grassland}, booktitle = {Ecosystems}, year = {2018}, month = {08/2018}, publisher = {Ecological Society of America}, organization = {Ecological Society of America}, address = {New Orleans, LA}, abstract = {

Semiarid grasslands have crossed thresholds to shrub-dominated states due to heavy grazing episodes and their after-effects. Extreme weather events and restoration actions can catalyze varying degrees of grass recovery. While we understand these thresholds in biophysical terms, we have scarcely explored their ultimate societal causes. I will reconstruct thought processes underpinning historical desertification events on the Jornada Experimental Range, including some recent first-hand experiences. I also describe how such {\textquotedblleft}mental models{\textquotedblright} underpin restoration success. Given the large management extents and heterogeneity inherent to drylands, I argue that appropriate mental models are the most important tools we have to manage thresholds.

}, author = {Brandon T Bestelmeyer} } @proceedings {JRN54863, title = {Understanding spatial variability in perennial grass restoration following shrub removal in the Chihuahuan Desert: The restore New Mexico collaborative monitoring program}, volume = {January 28-February 2, 2018}, year = {2018}, month = {01/28/2018}, publisher = {Society for Range Management Meeting Proceedings}, address = {Reno, NV}, abstract = {

Grassland to shrubland transitions are well documented throughout the desert grassland region of the Chihuahuan Desert. These transitions were triggered in the early 20th century by overgrazing of perennial grasses during drought periods, loss of fire regimes, and seed dispersal by livestock. Shrublands dominated by C3 species are highly resilient to natural disturbances, so herbicides specific to the C3 photosynthetic pathway are used to reduce the competitive preemption of soil water resources by shrubs and trigger the recovery of C4 perennial grasses. Anecdotally, there is evidence that shrub management treatments have been effective in some cases, but not in others, creating controversy about their value. As part of the Restore New Mexico partnership, we initiated a region-scale, long-term monitoring experiment embedded within shrub management treatments beginning in 2007. Within shrub management areas, we created treatment and control plots that were matched according to soils/ecological sites and initial state prior to treatments, such that control plots were excluded from treatment. Line-point intercept was used to measure cover prior to and after treatments. In addition, we sampled older treatments (2004 and earlier) using space-for-time substitution assumptions. Our records to date indicate that 1) treatments are generally effective in increasing perennial grass cover, 2) the composition of grasses that increase usually differs from that of putative reference states, creating {\textquotedblleft}novel ecosystems{\textquotedblright} and 3) soil and climate properties are related to the magnitude of grass response to treatments; specifically, loamy soils and drier climates yield reduced grass response. Experimental monitoring data can be used to refine restoration approaches and resolve controversies about them.

}, author = {Brandon T Bestelmeyer and Laura M. Burkett and Leticia Lister} } @conference {JRN54945, title = {Using ecological sites and state and transition models to support objective based conservation planning}, booktitle = {73rd Soil and Water Conservation Society International Conference}, year = {2018}, month = {07/2018}, address = {Albuquerque}, abstract = {

Use of Ecological Site Information, Ecological Site Descriptions (ESDs), and State and Transition Models (STMs) in the 9 Step Conservation Planning Process on all land uses will be covered to support objective based conservation planning. ESDs provide land managers the information needed for evaluating land use suitability, response to different management activities or disturbance processes, and ability to sustain productivity over the long term. Integrating ESDs is the most spatially and temporally relevant model for a conservation planner to use for multiple land uses when discussing client objectives, defining resource concerns, conducting inventories, selecting applicable practices/management measures, monitoring effects, and supplying feedback. Site specific use of STMs assure that conservation planners collect, organize, manage, and apply ecologically based conservation planning information. STMs describe a range of resource conditions (e.g., states and phases) and processes (e.g., time, triggers, succession, disturbances, management activities/practices) related to transitions in each land use. Development of hierarchical nested STMs for major land uses and sub-land uses that describe a common range of resource conditions, along with the conservation practices/management systems that can drive a desired resource change, allow the planner to focus on applicable land use(s) that apply. STMs can also be utilized to avoid making common conservation planning mistakes, such as utilizing practices that are not well-suited or applying practices that have negative effect on resource conditions.\  Transitions between states include information about conservation practices and adaptive management concepts that can achieve desired resource conditions. States and phases are explicitly connected to soil health, soil health indicators, and soil health management systems; and can be utilized across the country on a wide range conditions to guide conservation planning.

}, author = {Brandon T Bestelmeyer and Joel R. Brown and Strait, Richard} } @conference {JRN54789, title = {Apathy, ignorance, and poor governance: the three-headed Hydra of drylands}, booktitle = {Ecological Society of America Annual Meeting}, year = {2017}, month = {08/2017}, publisher = {Ecological Society of America Annual Meeting}, organization = {Ecological Society of America Annual Meeting}, address = {Portland, OR}, abstract = {

Proximate threats to drylands include drivers such as overharvesting or land conversion. I argue that these proximate threats are ultimately related to popular and scientific perceptions of drylands and, consequently, how investments translate into governance. First, what is degradation in drylands? Scientists debate this topic and the public often doesn{\textquoteright}t care. Second, if a dryland is judged to be degraded, what should we do about it? Ignorance of social and ecological processes can lead to actions (or inactions) that make things worse. To better manage drylands, we need to popularize their importance and improve models of how they function.

}, author = {Brandon T Bestelmeyer} } @conference {JRN54805, title = {A conceptual model of agroecosystem function as a basis for synthesis}, booktitle = {Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting}, year = {2017}, month = {10/2017}, publisher = {Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting}, organization = {Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting}, address = {Tampa, Florida}, abstract = {

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

}, author = {Brandon T Bestelmeyer and S. Spiegal and Timothy Strickland and Hilary Swain and Elizabeth H. Boughton} } @inbook {JRN54699, title = {State and transition models: Theory, applications, and challenges. In: Briske, D.D. Rangeland Systems: Processes, Management and Challenges}, booktitle = {Springer Series on Environmental Management}, year = {2017}, pages = {303-345}, publisher = {Rangeland Systems}, organization = {Rangeland Systems}, chapter = {9}, address = {Gewerbestrasee, Switzerland}, abstract = {

State and transition models (STMs) are used for communicating about ecosystem change in rangelands and other ecosystems, especially the implications for management. The fundamental premise that rangelands can exhibit multiple states is now widely accepted. The current application of STMs for management, however, has been limited by both the science and the ability of institutions to develop and use STMs. In this chapter, we provide a comprehensive and contemporary overview of STM concepts and applications at a global level. We first review in detail the ecological concepts underlying STMs with the goal of bridging STMs to the recent theoretical developments and debates in ecology. We then provide a synthesis of the history of STM development and current applications in rangelands of Australia, Argentina, the United States, and Mongolia, exploring why STMs have been limited in their application for management. Key challenges in the use of STMs for management are addressed and recent advances that may improve STMs, including participatory approaches in model development, the use of STMs within a structured decision-making process, and mapping of ecological states are described. We conclude a summary of actions that could increase the utility of STMs for collaborative adaptive management in the face of global change.

}, doi = {10.1007/978-3-319-46709-2_9}, url = {files/bibliography/17-010.pdf}, author = {Brandon T Bestelmeyer and A.J. Ash and Joel R. Brown and Densambuu, M. and Maria Fern{\'a}ndez-Gim{\'e}nez and Jane M. F. Johnson and Matthew Levi and Dardo Rub{\'e}n L{\'o}pez and Rumpff, L. and H. Raul Peinetti and P. L. Shaver} } @conference {JRN54646, title = {Is desertification a dirty word?}, booktitle = {Ecological Society of America}, year = {2016}, month = {08/2016}, publisher = {Ecological Society of America Abstracts}, organization = {Ecological Society of America Abstracts}, address = {Fort Lauderdale}, abstract = {

Desertification refers to land degradation in drylands. The term is widely used in ecology and is the basis for a United Nations convention. At best, it is a vague term. At worst, it has been referred to as the {\textquotedblleft}lie of the land{\textquotedblright} and a tool by which powerful actors disenfranchise less powerful ones. I argue that reference to specific state change processes can promote solutions. Desertification in reference to ecological processes should be stricken from scientific discourse. Nonetheless, like other dirty words, {\textquotedblleft}desertification{\textquotedblright} draws attention to critical problems.

}, author = {Brandon T Bestelmeyer} } @article {JRN54697, title = {Improving the effectiveness of ecological site descriptions: General state-and-transition models and the Ecosystem Dynamics Interpretive Tool (EDIT)}, journal = {Rangelands}, volume = {38:329-335}, year = {2016}, type = {12/2016}, abstract = {

State-and-transition models (STMs) were conceived as a means to organize and communicate information about ecosystem changes and how to manage them. Information within STMs applies to ecological land classes, such as ecological sites, that possess similar vegetation states. The value of STMs for rangeland managers is in fostering a general understanding of how rangelands function and respond to management actions, thereby leading to more efficient and effective allocation of management efforts. \ STMs can play an important role in most steps of conservation planning.

}, doi = {10.1016/j.rala.2016.10.001}, url = {files/bibliography/16-034.pdf}, author = {Brandon T Bestelmeyer and Jebediah C. Williamson and Curtis Talbot and Cates, Greg and Danielle Duni and Joel R. Brown} } @conference {JRN54647, title = {Tipping points in rangeland social-ecological systems of the Southwest US: Past and present}, booktitle = {Ecological Society of America}, year = {2016}, month = {08/2016}, publisher = {Ecological Society of America Abstracts}, organization = {Ecological Society of America Abstracts}, address = {Fort Lauderdale, FL}, abstract = {
Background/Question/Methods: \ The advent of social-ecological system perspectives has led to new questions about the causes and consequences of global change. Nearly all research in rangeland ecosystems of the U.S. has focused on transitions in vegetation (such as grasslands to shrublands) casting human activities (especially livestock production) as an external driver of change. Here, we consider abrupt change in Southwestern rangelands from a social-ecological systems perspective. We consider the theory that abrupt changes in societal organization and environment are due to changes in multiple slow variables, including social factors, government policy, markets, and technology, interacting with abrupt {\textquotedblleft}trigger{\textquotedblright} events, especially drought, that leads to acute limitations and longer-term reductions of perennial grass forage. We draw upon a number of data sources to characterize and explain social-ecological transitions over the last 160 years in southwestern New Mexico, and offer predictions about the next transition.
Results/Conclusions: In the late 1800s, government policies to encourage settlement as well as access to foreign capital, alongside the proliferation of railroads and water developments, led to a rapid increase in livestock numbers and large cattle ranches (transition 1). Subsequent multi-year droughts and overstocking led to catastrophic livestock losses, reductions of perennial grass cover, and new government policies that promoted a transition to smaller ranching enterprises in the 1930s (transition 2). Since that time, severe droughts have led to additional loss of perennial grasslands and gradual shrub encroachment, alongside increased urbanization and recognition of environmental degradation. Recent livestock numbers are considerably lower than carrying capacities estimated in the mid-20th century. Ranch ownership has been unstable in the least favorable landscapes, associated with only patchy ongoing reduction of perennial grass cover. Predicted declines in regional water balance and increased interannual precipitation variability will again accelerate loss of perennial grasses, increase dominance by unpalatable shrubs, and reduce availability of harvested forages (hay) necessary for sustaining small-scale ranching operations. We predict that the next social-ecological transition will involve 1) the dissolution of some small ranching enterprises and aggregation of private and leased land into larger, corporate operations that may not emphasize livestock production, 2) increased use of public lands for renewable energy production and wilderness, and possibly the reorganization of public land leasing strategies, 3) the transformation of most remaining grassland areas to shrublands, and 4) the potential for greatly increased wind erosion rates and declining air quality for urban centers.
}, author = {Brandon T Bestelmeyer and Kris Havstad and O. E. Sala and N. F. Sayre and Nicholas Webb} } @conference {JRN54442, title = {Collaborative adaptive landscape management (CALM) in rangelands: Discussion of general principles}, booktitle = {68th Annual Society for Range Management Meeting}, year = {2015}, month = {01/2015}, publisher = {Sociiety for Range Management}, organization = {Sociiety for Range Management}, address = {Sacramento, CA}, abstract = {

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

}, author = {Brandon T Bestelmeyer and J.R. Miller} } @article {JRN54148, title = {Desertification, land use, and the transformation of global drylands}, journal = {Frontiers in Ecology and the Environment}, volume = {13}, year = {2015}, month = {02/2015}, pages = {28-36}, chapter = {28}, abstract = {

Desertification is an escalating concern in global drylands, yet assessments to guide management and policy responses are limited by ambiguity concerning the definition of {\textquotedblleft}desertification{\textquotedblright} and what processes are involved. To improve clarity, we propose that assessments of desertification and land transformation be placed within a state change{\textendash}land-use change (SC{\textendash}LUC) framework. This framework considers desertification as state changes occurring within the context of particular land uses (eg rangeland, cropland) that interact with land-use change. State changes that can be readily reversed are distinguished from regime shifts, which are state changes involving persistent alterations to vegetation or soil properties. Pressures driving the transformation of rangelands to other types of land uses may be low, fluctuating, or high, and may influence and be influenced by state change. We discuss how the SC{\textendash}LUC perspective can guide more effective assessment of desertification and management of drylands.

}, keywords = {desertification, land management, land use, land use change, SC-LUC, state change}, doi = {10.1890/140162}, url = {/files/bibliography/15-004.pdf}, author = {Brandon T Bestelmeyer and Gregory S. Okin and Danielle Duni and Steven R. Archer and N. F. Sayre and Jebediah C. Williamson and Jeffrey E. Herrick} } @conference {JRN54423, title = {Geography as destiny? Social and ecological resilience in rangelands of the American southwest}, booktitle = {100th Annual Meeting, Ecological Society of America}, year = {2015}, month = {08/2015}, publisher = {ESA}, organization = {ESA}, address = {Baltimore, MD}, abstract = {

Background/Question/Methods:\  Social-ecological systems perspectives focus on the reciprocal relationships between human and natural ecosystem elements and how these interactions determine human well-being, ecological state change, and land use change. In the arid southwestern US, which is dominated by ranching, a deeper understanding of social-ecological relationships is critical because land use change is accelerating. Productive cattle ranches, for example, can remain within family ownership for generations, whereas limited ecological potential, ecological degradation, and the {\textquotedblleft}impermanence syndrome{\textquotedblright} can lead to repeated sales of other ranches. We asked whether we could predict expressions of social resilience (intrafamilial transfer of ownership vs. repeated ranch turnover to new owners) as a function of biophysical and geographic variables. In other words, are some ranches prone to failure? We studied an area dominated by federal public land (Bureau of Land Management grazing allotments) in southwestern New Mexico, USA. We examined the relationships of 1) frequency of ranch turnover and 2) intrafamilial transfer with variables related to 3) ecological resilience (soils, climate, departure from reference state) and 4) factors that may contribute to the perception of ranch impermanence (grazing allotment size and distance to the US-Mexico border and major cities). The dataset included 432 grazing allotments examined over a 70 year period.
Results/Conclusions: Our analysis supported the hypothesis that ranch ownership dynamics were related to ecological potential, ecological state, and ranch impermanence factors. The frequency of ranch turnover was positively related to the dominance of low-resilience (sandy) soils and degraded ecological states and negatively related to mean annual precipitation, distance from the US-Mexico border, and distance to major cities. Ranch turnover was positively related to grazing allotment size, perhaps because the largest allotments were established in the poorest soils under the Taylor Grazing Act (1934). In contrast, intrafamilial transfers were positively related to mean annual precipitation and distance from cities but negatively related to allotment size and the dominance of sandy soils. Thus, geographic position within the study area appears to be an important determinant of past land ownership dynamics. Future land use changes, including urban expansion, energy development, and establishment of conservation areas might also be predicted by ecological and impermanence factors.\  Abstract $\#$ LNG 1-8.

}, author = {Brandon T Bestelmeyer and R. K. Skaggs and Dawn M. Browning and Jebediah C. Williamson and Wojan, Chris} } @article {JRN54567, title = {Land Ecology Essay II: Thresholds, novel ecosystems, and the sanctity of history}, journal = {Rangelands}, volume = {37}, year = {2015}, month = {12/2015}, pages = {244-246}, chapter = {244}, abstract = {

Dr. Brandon Bestelmeyer is a research ecologist with the USDA Agricultural Research Service{\textquoteright}s Jornada Experimental Range and the Jornada Basin LTER at New Mexico State University in Las Cruces, New Mexico. He regularly writes about rangeland issues on the Land Ecology blog.

To read more of Brandon{\textquoteright}s essays, visit http://landecology.org/.

{\textquotedblleft}Land ecology{\textquotedblright} honors the holistic approach to the knowledge needed to support land stewardship into our increasingly uncertain future. Here we share an expanded version of one of Brandon{\textquoteright}s recent essays.

}, keywords = {Land Ecology, novel ecosystems, Sanctity of History, thresholds}, doi = {10.1016/j.rala.2015.10.009}, url = {/files/bibliography/15-024.pdf}, author = {Brandon T Bestelmeyer} } @conference {JRN54429, title = {Operationalizing resilience using state and transition models}, booktitle = {68th World Congress on Ecological Restoration}, year = {2015}, month = {08/2015}, address = {Manchester, UK}, abstract = {

In management, restoration, and policy contexts, the notion of resilience can be confusing. Systematic development of conceptual models of ecological state change (state transition models; STMs) can help overcome semantic confusion and promote a mechanistic understanding of resilience. Drawing on examples from rangelands, I describe basic state change concepts (equilibrium, nonequilibrium, and regime shifts) and how they are matched (or mismatched) to specific ecosystems via historical, comparative, experimental, and monitoring evidence. A key issue is to distinguish regime shifts from other forms of state change. STMs should distinguish strategies used to prevent regime shifts vs. the restoration and management of historical/hybrid/novel ecosystems following a regime shift. Important challenges in the development of STMs include 1) defining reference conditions, 2) considering climate change, and 3) information delivery to users.\  Paper No. SY48.2.

}, author = {Brandon T Bestelmeyer} } @conference {JRN54438, title = {Spatial scaling concepts as applied to the assessment and restoration of drylands}, booktitle = {9th US IALE (Interantional Association of Landscape Ecology) World Congress}, year = {2015}, month = {07/2015}, address = {Portland, OR}, abstract = {

Scaling concepts are important because they induce people to think about processes and relationships that might otherwise be overlooked. For land management-related activities, the challenge is to incorporate scaling concepts into routine observation, evaluation, and planning. Drawing on experiences trying to incorporate ecological science into land management planning in drylands, I suggest that three basic scaling principles are becoming common knowledge (and sometimes conventional wisdom). 1) {\textquoteleft}The whole is greater than the sum of its parts{\textquoteright}: The arrangement of distinct land areas within a patch or landscape mosaic can produce emergent properties as a consequence of spatial interactions among adjacent land areas. 2) {\textquoteleft}Location matters{\textquoteright}: Spatial context provided by the landscape can influence the properties of specific locations. 3) {\textquoteleft}How (not to) lie with maps{\textquoteright}: the results of analyses conducted using geographic information systems software depend on the rules by which the map was produced and how the mapped units are interpreted. I will illustrate the importance of these principles for dryland management using examples and discuss how we might better incorporate the principles into routine management activities.\  Abstract $\#$ S33.

}, author = {Brandon T Bestelmeyer} } @article {JRN54150, title = {Deforestation of "degraded" rangelands: The Argentine Chaco enters the next state of the anthropocene}, journal = {Rangelands}, volume = {36}, year = {2014}, month = {08/2014}, pages = {36-39}, chapter = {36}, abstract = {

Twenty years ago I completed my Master\’s work in the Chaco forests of northern Argentina. The native forests are, in fact, rangelands. In addition to livestock grazing, there is timber extraction, wildlife harvest (think tegu lizard cowboy boots), and charcoal production. I took part in a project comparing biodiversity among production systems. A new system promised to reverse biodiversity loss and soil degradation. But it\’s a moot point now since much of that forest has been cleared for cropland\—the highest rate of tropical forest loss in the world.

}, doi = {10.2111/Rangelands-D-14-00026.1}, url = {/files/bibliography/14-033.pdf}, author = {Brandon T Bestelmeyer} } @conference {JRN54422, title = {Critical thresholds and recovery of Chihuahuan Desert grasslands: Insights from long-term data}, booktitle = {98th Annual Meeting, Ecological Society of America}, year = {2013}, month = {08/2013}, publisher = {ESA}, organization = {ESA}, address = {Minneapolis, MN}, abstract = {

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

}, author = {Brandon T Bestelmeyer and Kris Havstad and L.N. Svejcar and Danielle Duni and Gregory S. Okin and Debra C. Peters} } @proceedings {49837, title = {State-and-transition models as guides for adaptive management: What are the needs?}, year = {2013}, month = {04/2013}, pages = {27-33}, address = {Santa Rosa, La Pampa, Argentina}, abstract = {

State and transaction models (STMs) were conceived as a means to organize information about land potential and vegetation dynamics in rangelands to be used in their management. The basic idea is to describe the plant community states that can occur on a site and the causes of transitions between these states. STMs are not bound to any particular theory about how vegetation should change, so they are flexible and able to represent succession, event-driven change, and critical or abrupt transitions to alternative sites.\  The diagrammatic and narrative portions of STMs synthesize various sources of knowledge about an ecosystem, including scientific results, historical anecdotes, and local knowledge to resent a set of explanations and predictions for how ecosystems can respond to natural events and management actions.

}, url = {/files/bibliography/13-015.pdf}, author = {Brandon T Bestelmeyer and Joel R. Brown and Bulgamaa Densambuu and Kris Havstad and Jeffrey E. Herrick and H. Raul Peinetti} } @article {49838, title = {A test of critical thresholds and their indicators in a desertification-prone ecosystem: more resilience than we thought}, journal = {Ecology Letters}, volume = {16}, year = {2013}, month = {01/2013}, pages = {339-345}, chapter = {339}, abstract = {

Theoretical models predict that drylands can cross critical thresholds, but experimental manipulations to evaluate them are non-existent. We used a long-term (13-year) pulse-perturbation experiment featuring heavy grazing and shrub removal to determine if critical thresholds and their determinants can be demonstrated in Chihuahuan Desert grasslands. We asked if cover values or patch-size metrics could predict vegetation recovery, supporting their use as early-warning indicators. We found that season of grazing, but not the presence of competing shrubs, mediated the severity of grazing impacts on dominant grasses. Recovery occurred at the same rate irrespective of grazing history, suggesting that critical thresholds were not crossed, even at low cover levels. Grass cover, but not patch size metrics, predicted variation in recovery rates. Some transition-prone ecosystems are surprisingly resilient; management of grazing impacts and simple cover measurements can be used to avert undesired transitions and initiate restoration.

}, keywords = {desertification, early warning, grazing, long-term experiment, patch size, regime shift, resilience, state-transition model}, doi = {10.1111/ele.12045}, url = {/files/bibliography/13-005.pdf}, author = {Brandon T Bestelmeyer and Danielle Duni and D. K. James and Laura M. Burkett and Kris Havstad} } @article {49875, title = {Big questions emerging from a century of rangeland science and management}, journal = {Rangeland Ecology and Management}, volume = {65}, year = {2012}, month = {11/2012}, pages = {543-544}, chapter = {543}, abstract = {

This special feature commemorating the Jornada centennial addressed several big questions about the future of rangelands, including how livestock production can be sustained with reduced grass cover, responses to invasive species, and how to manage for diverse ecosystem services (among others).

}, doi = {10.2111/REM-D-12-00112.1}, url = {/files/bibliography/12-028.pdf}, author = {Brandon T Bestelmeyer and Richard E. Estell and Kris Havstad} } @conference {JRN54588, title = {Data support for a state-and-transition model: What have we learned?}, booktitle = {Society for Range Management, 65th Annual Meeting}, year = {2012}, month = {01/2012}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Spokane, WA}, abstract = {

State-and-transition models (STMs) were conceived as a means to synthesize knowledge about alternative plant communities and the processes that lead to transitions among them for specific land areas. STMs that have been developed over the past decade have often been limited by 1) a lack of detail on ecological mechanisms and management effects and 2) an over-reliance on expert knowledge and casual observations that are seldom critically evaluated. We used a state-and-transition model developed 10 years ago, in consultation with local experts, as a basis to examine how a model{\textquoteright}s structure would be changed via changes to model concepts, inclusion of a broad-scale, data-rich inventory dataset, and new experiments and monitoring. We found that elements of the initial model (Sandy ecological site, Chihuahuan Desert, Major Land Resource Area 42.2) were supported by the data, yet others were not. We found that the reference state was more resilient, an eroded shrubland state could attain higher grass cover, and that grasses and shrubs coexist over a wider range of values than previously assumed. We also found that the model could be simplified by reducing the number of states and quantitative criteria for ecological states and community phases were developed. This assessment suggests that a combination of local/expert knowledge and different kinds of data can be brought together to produce improved STMs. Even if this level of effort is not possible for all STMs in area, it should be possible for widespread or {\textquotedblleft}benchmark{\textquotedblright} ecological sites in most Major Land Resource Areas.

}, author = {Brandon T Bestelmeyer and D.D. Briske and Maria Fern{\'a}ndez-Gim{\'e}nez and Wu, X.B.} } @article {49873, title = {Grand challenges for resilience-based management of rangelands}, journal = {Rangeland Ecology and Management}, volume = {65}, year = {2012}, month = {11/2012}, pages = {654-663}, chapter = {654}, abstract = {

The social and ecological contexts for rangeland management are changing rapidly, prompting a reevaluation of science, management, and the linkages between them. Here, we argue that the recent transformation from a steady state to an ecosystem management model has served the rangeland profession well, but that further transformation to resilience-based management is required to ensure that rangeland services will continue to benefit society in an era of rapid change. Resilience-based management emphasizes collaborative management and social learning to guide adaptation and transformation in social-ecological systems. The objectives of this forum are to: 1) justify the need for adopting resilience-based management, 2) identify the challenges that will be encountered in its development and implementation, and 3) highlight approaches to overcoming these challenges. Five categories of challenges confronting the adoption of resilience-based management, based upon the insights of 55 of rangeland researchers that have contributed to this special issue, were identified as: a) development of knowledge systems to support resilience-based management, b) improvement of ecological models supporting science and management, c) protocols to assess and manage tradeoffs among ecosystem services, d) use of social-ecological system perspectives to achieve greater stakeholder participation, and e) reorganization of institutions to support resilience-based management. It has become clear that greater scientific knowledge by itself is insufficient to promote resilience-based management in rangelands. Resolving the challenges presented here will require the creation of stronger partnerships between ecosystem managers, science organizations, management agencies, and policymakers at local, regional, and national scales. The creation of social learning institutions tied to evolving knowledge systems is our best hope to guide adaptation and transformation in rangelands in the coming century.

}, keywords = {adaptive management, ecosystem services, knowledge systems, postmodern science, social-ecological systems, transformation}, doi = {10.2111/REM-D-12-00072.1}, url = {/files/bibliography/12-032.pdf}, author = {Brandon T Bestelmeyer and D.D. Briske} } @inbook {49874, title = {Is the historical range of variation relevant to rangeland management?}, booktitle = {Historical Environmental Variation in Conservation and Natural Resources Management: Past, Present, and Future}, year = {2012}, pages = {289-296}, publisher = {Wiley-Blackwell}, organization = {Wiley-Blackwell}, chapter = {21}, abstract = {

Rangelands occupy about 40\% of the Earth{\textquoteright}s terrestrial surface, comprising grasslands, shrublands, and deserts (Havstad et al., 2007). Over a billion people live in rangelands, engaged primarily in pastoralism and limited crop agriculture for subsistence. Rangelands can be ideal coupled human-natural systems. They can harbor great biodiversity and beauty, while at the same time providing food and soul-enriching connections between humans and the natural world. Resources can be exploited in grazing ecosystems such that most historical or natural elements are sustained (Brown and MacDonald 1995). The sustainable partnership of people and rangelands, however, has not been easy in many places. Recent estimates suggest that a large proportion of rangelands has become degraded, where degradation includes effects ranging from shifts in species composition to soil loss. These changes have been harmful for both biodiversity and human welfare. Worse, rangeland degradation is expected to accelerate with increases in human population and regional aridification (Millenium Ecosystem Assessment 2005). In this essay, I offer some thoughts on the utility of historical range of variation concepts (hereafter HRV) to address the core problem of managing change in rangelands. I argue that, although HRV has value, it is not by itself a firm basis for rangeland management.

}, keywords = {book, chapter, conservation, environmental variation, historical natural resource management, report}, doi = {10.1002/9781118329726.ch21}, author = {Brandon T Bestelmeyer}, editor = {J.A. Wiens and Regan, C. and Hayward, G. and Safford, H.} } @article {49931, title = {Analysis of abrupt transitions in ecological systems}, journal = {Ecosphere}, volume = {2}, year = {2011}, month = {12/2011}, pages = {1-26}, type = {Article 129}, chapter = {1}, abstract = {

The occurrence and causes of abrupt transitions, thresholds, or regime shifts between ecosystem states are of great concern and the likelihood of such transitions is increasing for many ecological systems. General understanding of abrupt transitions has been advanced by theory, but hindered by the lack of a common, accessible, and data-driven approach to characterizing them. We apply such an approach to 30 \– 60 years of data on environmental drivers, biological responses, and associated evidence from pelagic ocean, coastal benthic, polar marine, and semi-arid grassland ecosystems. Our analyses revealed one case in which the response (krill abundance) linearly tracked abrupt changes in the driver (Pacific Decadal Oscillation), but abrupt transitions detected in the three other cases (sea cucumber abundance, penguin abundance, and perennial grass production) exhibited hysteretic relationships with drivers (wave intensity, sea-ice duration, and amounts of monsoonal rainfall, respectively) through a variety of response mechanisms. The use of a common approach across these case studies illustrates that: the utility of leading indicators is often limited and can depend on the abruptness of a transition relative to the lifespan of responsive organisms and observation intervals; information on spatiotemporal context is useful for comparing transitions; and ancillary information from associated experiments and observations informs interpretations of response-driver relationships. The understanding of abrupt transitions offered by this approach provides information that can be used to manage state changes and underscores the utility of long-term observations in multiple sentinel sites across a variety of ecosystems.

}, keywords = {alternative states, Bouteloua eriopoda, desert grassland, krill, leading indicators, Nyctiphanes simplex, Pachythyone rubra, Penguins, Pygoscelis, regime shifts, sea cucumbers, thresholds}, doi = {10.1890/ES11-00216.1}, url = {/files/bibliography/11-036.pdf}, author = {Brandon T Bestelmeyer and Ellison, Aaron M. and William R. Fraser and Gorman, Kristen B. and Sally J. Holbrook and C. Laney and Mark D. Ohman and Debra C. Peters and Pillsbury, Finn C. and Andrew Rassweiler and Russell J. Schmitt and Sharma, Sapna} } @conference {JRN54586, title = {Grassland, shrubland and savanna stewardship: where do we go from here?}, booktitle = {96th Ecological Society of America Annual Meeting}, year = {2011}, month = {08/2011}, publisher = {Ecological Society of America}, organization = {Ecological Society of America}, address = {Austin, Texas}, abstract = {Scientific efforts to understand grasslands, shrublands and savannas and thereby develop sustainable management practices are roughly 100 years old. What have we learned in that time? Several assumptions made by scientists and policymakers early in the 20th century have proved mistaken, resulting in persistent degradation and many cases of unintended negative consequences. In particular, the belief that rangelands were only useful for livestock production no longer holds, and Clementsian ideas of succession and linear relations across scales of space and time have had to be replaced in light of empirical and theoretical advances in rangeland ecology.Successful stewardship in the 21st century will require policy revisions that address changing socio-economic conditions on rangelands in the US and abroad. Rapid land-use change{\textemdash}from livestock production to agriculture, urban development, and industry{\textemdash}requires policies that prevent fragmentation and preserve management options such as fire restoration. The discipline of rangeland ecology should partner with ranchers and pastoralists to study management effects at large spatial and long temporal scales, and to identify the times and places where opportunistic management practices can be implemented most effectively.}, author = {Brandon T Bestelmeyer and N. F. Sayre} } @inbook {49929, title = {Landscape approaches to rangeland conservation practices}, booktitle = {Conservation Benefits of Rangeland Practices: Assessment, Recommendations, and Knowledge Gaps}, year = {2011}, pages = {337-370}, publisher = {Allen Press}, organization = {Allen Press}, chapter = {8}, address = {Lawrence, KS}, abstract = {Our review indicates that landscape perspectives are needed to ensure the long-term success conservation practices in rangelands. We recommend that conservation practitioners consider several scales of spatial pattern and related spatial processes, including cumulative effects, each time a practice is applied. A large body of literature supports the utility of a landscape perspective. The core concepts include spatial heterogeneity, spatial pattern, and spatial scaling. Spatial heterogeneity is used to understand why a practice succeeds or fails in different areas. Spatial heterogeneity can also be a primary goal of practices. Spatial patterns are used to indicate critical processes that are not reflected in other measures, such as connectivity for wildlife movement or runoff and erosion potential. Patterns too can be a conservation objective. Spatial scaling is used to understand the dimensions of the land area over which spatial interactions link practices in one place to effects in other places, and conversely, how characteristics of the landscape affect the local success of a practice. The concepts are increasingly being connected to practical tools that can be used by planners. The tools can be used both to help design practices and to design the monitoring programs that evaluate their effects.\  A spatial hierarchy focuses attention on the data needed at each spatial scale governing ecological processes of interest. In order of decreasing scale, major land resource areas, soil geomorphic systems, watersheds, ecological sites, states or plant communities, and patches each relate to processes governing the management of rangelands. Furthermore, consideration of societal information such as land ownership is usually needed at broad scales. Each of these data sources can be consulted in a systematic way, which we described in nine steps, to design and evaluate practices in a landscape. While some of the tools are already used by conservation planners, the development of others will require a scientific and institutional investment by the federal government and support by universities and other science providers. Spatial data information systems should be developed that link maps, models, and pattern-based metrics to support planning and monitoring design. Databases are needed to house the resulting data alongside information on their landscape context. The interpretations of these data should be linked to ESDs. Foremost, we must invest in training and research to instill an understanding of the concepts and a capacity for reasoning about landscape processes. We suspect that such investments would pay for themselves, and then some, by improving conservation effectiveness in the millions of acres of rangelands that will be treated in years to come.}, keywords = {book, chapter, conservation practices, landscape approaches, rangeland, report}, isbn = {978-0-9849499-0-8}, url = {/files/bibliography/11-035.pdf}, author = {Brandon T Bestelmeyer and Wu, X.B. and Joel R. Brown and S. Fuhlendorf and G. Fults}, editor = {D.D. Briske} } @article {49928, title = {Spatial perspectives in state-and-transition models: A missing link to land management?}, journal = {Journal of Applied Ecology}, volume = {48}, year = {2011}, month = {03/2011}, pages = {746-757}, chapter = {746}, abstract = {Conceptual models of alternative states and thresholds are based largely on observations of ecosystem processes at a few points in space. Because the distribution of alternative states in spatially-structured ecosystems is the result of variations in pattern-process interactions at different scales, we argue that data and models need to explicitly consider ecosystem processes in the context of the spatial pattern of drivers, spatial dependence in responses to drivers, and the spatial structure of feedbacks. Here, we review the literature on spatial patterns and processes in the context of state transitions (or regime shifts) and draw upon examples from semiarid ecosystems to illustrate these linkages. We suggest three spatial perspectives be used to expand conceptual state-and-transition (S\&T) models to landscape systems. First, S\&T models should represent how spatial patterns of natural and anthropogenic drivers interact to initiate transitions. This would account for often observed situations wherein contrasting states occur along gradients of disturbance intensity or in different management units. Second, spatial dependence in response to drivers and triggers should be represented. This would help account for observed differences in ecological resilience tied to inherent spatial variation in environmental variables (e.g., soil and landform attributes) that mediate driver effects and lead to variation in the likelihood of state transitions. Third, the nature of feedbacks, how they propagate over time and space, and how they are conditioned by patterns of spatial dependence and drivers should be represented. At fine scales, changes in the nature and intensity of feedbacks may be associated with predictable changes in patch structure (e.g., fragmentation or coalescence processes foreshadowing thresholds). At coarser scales, feedbacks may be associated with the spatial extent and arrangement of land cover states, broad-scale resource redistribution (e.g., wind/water erosion/deposition) or land surface/climate interactions. S\&T conceptual models with a spatial component would make use of readily-obtainable patch-scale data to predict how the likelihood of transitions might vary across landscapes and to forecast changes leading to degradation or recovery. Such predictions would be valuable in the design of monitoring schemes aimed at adjusting management to avert crossing degradation thresholds and to take advantage of environmental conditions required to restore desired states.}, keywords = {Chihuahuan Desert, contagion, Iceland, monitoring, patch dynamics, regime shift, southern Great Plains, spatial dependence, thresholds}, doi = {doi: 10.1111/j.1365-2664.2011.01982.x}, url = {/files/bibliography/11-007.pdf}, author = {Brandon T Bestelmeyer and D. Goolsby and Steven R. Archer} } @proceedings {49930, title = {State-and-transition model archetypes: A global taxonomy of rangeland change}, volume = {IX}, year = {2011}, month = {04/2011}, pages = {60}, address = {Roxario, Argentina}, abstract = {State and transition models (STMs) synthesize science-based and local knowledge to formally represent the dynamics of rangeland and other ecosystems. Mental models or concepts of ecosystem dynamics implicitly underlie all management decisions in rangelands and thus how people influence rangeland sustainability. STMs use a combination of elements, including structured inventory and mapping, historical reconstruction, process-based comparisons and experiments, and local knowledge to develop formal models of ecosystem function. The models describe the mechanisms by which transitions among states occur and thus the interventions needed to achieve or sustain desired states. STMs are very useful tools, but are often difficult to construct. We ask whether we can identify a series of basic, archetypal models globally that could be matched to local ecosystems and assist in the development of local STMs.}, keywords = {conservation practices, ecological sites, monitoring, succession, thresholds}, author = {Brandon T Bestelmeyer and H. Raul Peinetti and Jeffrey E. Herrick and Diego Steinaker and Edgardo Adema} } @conference {JRN54457, title = {Degraded states, novel ecosystems, or reconfigured landscapes: How should we view ecosystem change in a changing world?}, booktitle = {63rd Society for Range Management Annual Meetings}, year = {2010}, month = {02/2010}, publisher = {Sociiety for Range Management}, organization = {Sociiety for Range Management}, address = {Denver, CO}, abstract = {

Climate change is predicted to cause gradual warming and changes in the amount and distribution of rainfall. Thus, the default assumption should be that attributes of rangelands will change, rather than stay as they have been. The talks in this symposium have described what may happen to rangeland communities and why. Here, we explore how managers and policymakers might evaluate and react to predicted ecosystem change. First, ecosystem change can be viewed as degradation to an alternative state in which the risks of transition have increased but managerial attention can preserve functions, and some essential services, of the original ecosystem. Second, ecosystem change may inevitably produce novel ecosystems with combinations of species, functions, and ecosystem services that are distinct from ancestral ecosystems (particularly via invasive species) and that should be accepted for what they are. Third, ecosystem change may reconfigure the relationships among attributes that existed in the ancestral landscape, such that adaptive management can be used to promote a combination of new and previously emphasized functions and services in different parts of a landscape. Depending on the nature of baseline, climate-driven ecosystem responses and managers{\textquoteright} ability to influence them, each of these reactions should be considered. We conclude by exploring how these distinct scenarios might be captured in state-and-transition models. Abstract $\#$ SYM-109.

}, author = {Brandon T Bestelmeyer and Joel R. Brown} } @article {50014, title = {An introduction to the special issue on ecological sites}, journal = {Rangeland}, volume = {32}, year = {2010}, month = {12/2010}, pages = {3-4}, chapter = {2}, abstract = {

The establishment of the Rangeland Interagency Ecological Site Manual by the Natural Resources Conservation Service (NRCS), Forest Service (FS), and the Bureau of Land Management (BLM) heralds a new era of rangeland management in the United States (http://www.fs.fed.us/biology/soil/Signed_RIESM_2010.pdf). The manual promises to establish a land stratification system and approaches for describing ecosystem structures, functions, and dynamics in the form of ecological site descriptions, such that they can be applied to all rangelands, no matter their jurisdiction or ownership. The common basis for decision-making will lead to improved coordination and more consistent, transparent, and useful application of science concepts in rangeland management. NRCS has had primary responsibility for the development of ecological site descriptions in the past. This responsibility will be now be shared by all three agencies. At this juncture, we summarize in this special issue the state of the art in the development of ecological site descriptions, recognizing that this art will evolve over the coming decades.

}, url = {/files/bibliography/10-041.pdf}, author = {Brandon T Bestelmeyer and Joel R. Brown} } @article {50013, title = {Practical guidance for developing state-and-transition models}, journal = {Rangelands}, volume = {32}, year = {2010}, month = {12/2010}, pages = {23-30}, chapter = {23}, abstract = {

State-and-transition models (STMs) are synthetic descriptions of the dynamics of vegetation and surface soils occurring within specific ecological sites. STMs consist of a diagram and narratives that describe the dynamics and its causes. STMs are developed using a broad array of evidence including historical information, local and professional knowledge, general ecological knowledge, and monitoring and experimental data from a specific ecological site or similar sites. We provide general guidance on the production of rangeland state-and-transition models with special attention to recent concepts. We describe preparation and a sequence of steps in the development of STMs that parallels the steps in ecological site development. STMs are usually developed alongside ecological site concepts because STMs help to define differences among sites. We follow the steps with a discussion of some common problems encountered by model developers and provide some advice for how to resolve them. We then conclude with some forward-looking ideas that bear upon the present-day development of STMs.

}, doi = {10.2111/RANGELANDS-D-10-00077.1}, url = {/files/bibliography/10-042.pdf}, author = {Brandon T Bestelmeyer and Moseley, Kendra and P. L. Shaver and H. Sanchez and D.D. Briske and Maria Fern{\'a}ndez-Gim{\'e}nez} } @conference {JRN54458, title = {Resilience mechanisms and recovery in a Chihuahuan Desert rangeland ecosystem}, booktitle = {95th Ecological Society of America Meeting}, year = {2010}, month = {08/2010}, address = {Pittsburga, PA}, abstract = {

Background: Desert grassland ecosystems of the Chihuahuan Desert, and other parts of the southwestern U.S., underwent significant changes from the late 1800s through the 1950s. Most often, grassland states were converted to shrubland states. Such transitions have been associated with diminished livestock production, erosion, reduced soil water retention and diminished net primary production, and biodiversity loss. Synthesizing across a number of data sources, we first describe the social and ecological mechanisms that precipitated transitions. We then describe several elements of resilience in the Chihuahuan Desert that have been discovered and their implications for ongoing management. Results/Conclusions: Evidence from the Jornada Basin LTER indicates that transitions from grassland to shrublands were triggered by a failure to reduce livestock numbers during periods of low rainfall. These events caused initial perennial grass mortality and subsequent feedbacks with soil degradation, paralleled by shrub establishment and survival. Theory and observation suggests that a threshold is crossed once sufficient grass biomass is lost and feedbacks with soil erosion and reduced water availability drive remaining grasses extinct. Recent work, however, indicates several factors that have contributed to grassland resilience in the face of these processes. First, the occurrence of transitions across the landscape was buffered by variation in soil and landscape properties that influence soil water availability such that grasses were preserved in many areas. Second, net primary productivity of eroding shrubland states is, remarkably, not lower than that of grasslands although the response of these states to rainfall differs. Third, a recent large precipitation event revealed that remnant and colonizing grasses can reverse perennial grass loss, even if temporarily, on what were thought to be irreversibly degraded soils. Finally, degradation episodes in the first half of the 20th century have radically transformed institutions and perceptions such that livestock management is more responsive to high-risk conditions. Here, as in other arid ecosystems, scientists have focused largely on the mechanisms of degradation rather than strategies to exploit resilience. Abstract $\#$ OOS 8-4

}, author = {Brandon T Bestelmeyer and Kris Havstad and Danielle Duni and Debra C. Peters} } @inbook {50074, title = {Resilience theory in models of rangeland ecology and restoration: the evolution and application of a paradigm}, booktitle = {New Models for Ecosystem Dynamics and Restoration}, year = {2009}, month = {2009}, pages = {78-95}, publisher = {Island Press}, organization = {Island Press}, address = {Washington, D.C}, abstract = {In this review, we will use our experiences and our ongoing collaborations to describe an approach that links new concepts regarding ecosystem dynamics to science, management and restoration activities in rangelands. First, we will review some novel elements and ideas connected to resilience theory that mark the evolution of an increasingly integrated paradigm for rangeland ecology. Lastly, we will present a sequence of science and management activities that we feel will allow the paradigm to gain traction in real-world management. It should be noted that our ideas are, in many cases, a work in progress and our hope is that readers are inspired to look more deeply into them, or to develop their own approaches.}, keywords = {ecology, models, paradigm, restoration}, author = {Brandon T Bestelmeyer and Kris Havstad and Damindsuren, B. and G. Han and Joel R. Brown and Jeffrey E. Herrick and Caitriana Steele and Debra C. Peters} } @conference {50070, title = {The spatial pattern of transition (spot): linking pattern, process, and scale to state-and-transition models}, booktitle = {62nd Society for Range Mangement Annual Meeting}, year = {2009}, month = {February 8-12, 2}, pages = {06-11}, publisher = {Society for Range Management}, organization = {Society for Range Management}, address = {Albuquerque, NM}, abstract = {Field implementation of conceptual state-and-transition models will benefit from explicit representations of spatial patterns of vegetation, soils and topography and the hydrological/eolian processes that link them. Here, we introduce the concept "spatial pattern of transition{\textquotedblright} (SPOT) as a means to understand the interrelationships and feedbacks among vegetation and soil spatial patterns, changes in those patterns over time, and the ecological processes governing that change. Patterns can vary with spatial scale and include vegetation patches in a matrix of bare ground or mosaics of alternative states or plant communities. Key concurrent processes include those affecting surface and subsurface hydrology, eolian transport, resource availability and plant response to stress and disturbance. We review the literature and our own work to establish general approaches to and insights from SPOT. First, we show that SPOT can be observed at multiple scales from remotely-sensed imagery and has been experimentally investigated and mathematically modeled. Second, we argue that SPOT is a consequence of three interacting factors: a) inherent, relative stable heterogeneity in soils, topography and geomorphology, b) disturbance processes such as grazing or fire, and c) feedbacks among plant attributes, surface soil properties, and material fluxes. Third, we show general classes of SPOT that are reliably associated with soil-geomorphic settings and climate zones. Finally, we demonstrate the consequences of SPOT for the development and practical use of state-and-transition models. In particular, we show that differences in SPOT influence (i) the scale at which state-and-transition models should defined, (ii) the ecosystem attributes we need to measure to define thresholds and monitor change, and hence, (iii) the appropriate spatial scale and frequency of observation.}, keywords = {SPOT, SRM, state and transition}, author = {Brandon T Bestelmeyer and D. Goolsby and Steven R. Archer} } @conference {JRN54456, title = {Spatial patterns in alternative states and thresholds: A missing link for management of landscapes?}, booktitle = {10th Biennial Conference for Research on the Colorado Plateau}, year = {2009}, month = {10/2009}, address = {Flagstaff, AZ}, abstract = {

The detection of threshold dynamics (and other dynamics of interest) would benefit from explicit representations of spatial patterns of disturbance, spatial dependence in responses to disturbance, and the spatial structure of feedbacks in the design of monitoring and management strategies. Spatially-structured ecosystems at landscape scales tend to exhibit signals of each of these processes and their interactions. The spatial pattern of disturbance is determined by natural or anthropogenic processes associated with land use. In the latter case, management units and resource use gradients within units often feature different states or indications of threshold risk. Spatial dependence in disturbance response accounts for differences in resilience caused by static environmental variations including soil and landform attributes. These factors determine the effect of disturbance on resource availability and species populations underlying transitions. The patterning of spatial dependence is detected via soil sampling and maps. Finally, the spatial structure of feedbacks accounts for how the initial state change in a location propagates over time and space, conditioned by the pattern of spatial dependence and disturbance. At fine scales, feedbacks may be detected via predictable changes in patch structure (e.g., fragmentation processes prior to crossing soil erosion thresholds). At broader scales, feedbacks may emerge between the distribution of states and broad-scale sediment redistribution (e.g., wind erosion) or even climate. We suggest that these three spatial patterns should be the basis for expanding conceptual state-and-transition models to landscape systems. These new conceptual models would contain predictions about how the likelihood of transition varies across a landscape as well as the patch-scale changes leading to, and determining the reversibility of, transitions. Both sets of predictions would be valuable guides in the design of monitoring to manage thresholds. A hierarchical approach to monitoring featuring ground-based observations coupled to remote-sensing is generally required.\  Pg. 40.

}, author = {Brandon T Bestelmeyer and D. Goolsby and Steven R. Archer} } @article {50071, title = {State-and-Transition models for heterogeneous landscapes: A strategy for development and application}, journal = {Rangeland Ecology and Management}, volume = {62}, year = {2009}, month = {01/2009}, pages = {1-15}, abstract = {

Interpretation of assessment and monitoring data requires information about reference conditions and ecological resilience. Reference conditions used as benchmarks can be specified via potential-based land classifications (e.g., ecological sites) that describe the plant communities potentially observed in an area based on soil and climate. State-and-transition models (STMs) coupled to ecological sites can specify indicators of ecological resilience and thresholds. Although general concepts surrounding STMs and ecological sites have received increasing attention, strategies for their data-driven development have not. In this paper, we outline concepts and a practical approach to potential-based land classification and STM development. Quantification emphasizes inventory techniques readily available to natural resource professionals and that can reveal processes interacting across spatial scales. We recommend a sequence of 8 steps for the co-development of land classes and STMs including 1) creation of initial ecological site concepts and STMs based on literature and workshops; 2) extensive, low-intensity traverses to assist in generating initial concepts and to plan inventory; 3) development of a spatial hierarchy for sampling based on climate, geomorphology, and soils; 4) stratified medium-intensity inventory of plant communities and soils across a broad extent and with large sample sizes; 5) storage of plant and soil data in a database; 6) model-building and analysis of inventory data to test initial concepts; 7) support and/or refinement of concepts; and 8) high-intensity characterization and monitoring of states. Second, we offer a simple example of how data assembled via our sequence can be used to refine ecological site classes and STMs. The linkage of inventory to expert knowledge and site-based mechanistic experiments and monitoring provides a powerful means for specifying management hypotheses and, ultimately, promoting resilience in grassland, shrubland, savanna and forest ecosystems.

}, keywords = {assessment, ecological resilience, monitoring, quantitative, state-and-transition}, doi = {10.2111/08-146}, url = {/files/bibliography/09-004.pdf}, author = {Brandon T Bestelmeyer and A.J. Tugel and G. Peacock and D. Robinett and P. L. Shaver and Joel R. Brown and Jeffrey E. Herrick and H. Sanchez and Kris Havstad} } @conference {50073, title = {Threshold models in restoration - can we ever predict threshold responses?}, booktitle = {19th Conference of Society for Ecological Restoration International}, year = {2009}, month = {08/2009}, address = {Perth, Western Australia, Australia}, abstract = {

Land managers and scientists often ask: \“How do I identify the threshold?\” or \“Where is the threshold?\” Such questions presume a great deal about the nature of thresholds that are, as yet, not generally understood and not necessarily general at all. In this talk, I review how the threshold concept has been considered in land management and argue five points. 1) Attempting to predict threshold responses is likely to be a waste of time in many cases. 2) We have not yet produced an adequate number of case histories about the consequences, scales, rates, and mechanisms of threshold behavior within different kinds of ecosystems, so it is difficult to structure monitoring programs to detect threshold responses. 3) Managing for resilient conditions, with attention to slow social and ecological variables, to minimize the risk of crossing a threshold is potentially useful but is controversial for managers. 4) We have a dim understanding of how inherent (i.e., not management-related) variations in landscapes influence threshold responses, but such understanding can be used to guide planning. 5) Recognizing the consequences of post-threshold states for restoration actions is the most straightforward use of the threshold concept at present. Examples are drawn from restoration approaches in the southwestern United States and elsewhere to support these assertions.

}, keywords = {restoration, threshold}, author = {Brandon T Bestelmeyer} } @conference {50072, title = {Threshold models linked to land classification and indicators as guides to restoration - propsects and pitfalls}, booktitle = {10th International Congress of Ecology: Ecology in a Changing Climate}, year = {2009}, month = {08/2009}, address = {Brisbane, Queensland, Australia}, abstract = {Threshold (or regime shift) models are useful for restoration because they match actions to conditions where benefits are likely to be maximized. The procedures by which threshold models should be applied, however, are in the early stages of development. Here, we describe ecological concepts and derivative elements of an approach to applying threshold models including 1) combining experiments, simulations, and local ecological knowledge to develop conceptual state-and-transition models representing specific geographic areas; 2) linking the models to soil, plant, and landscape process-based indicators detected in ground-based or remotely-sensed assessment; 3) recognizing model contingency with respect to varying land-use, soils and geomorphology, and climate; and 4) cooperative planning of restoration actions integrated with model-based experimentation and monitoring. We describe several tools that have been used for each element and limitations of the tools and concepts revealed in applications in the United States and Mongolia. We suggest that the integration of threshold/resilience concepts with scale-specific models, process-based indicators, spatial data on the biophysical and social environment, and restoration experiments is becoming an increasingly common solution to connecting abstract ideas with real-world restoration applications.}, keywords = {restoration, state-and-transition, STM, threshold}, author = {Brandon T Bestelmeyer and Jeffrey E. Herrick and D.D. Briske and Maria Fern{\'a}ndez-Gim{\'e}nez and Wu, X.B. and Joel R. Brown and Kris Havstad} } @proceedings {50168, title = {The regional ecology of alternative states and thresholds: Strategies for ecological site descriptions}, volume = {1}, year = {2008}, month = {June 30 -July 5,}, pages = {644}, publisher = {Guangdong People{\textquoteright}s Publishing House}, address = {Hohhot, China}, abstract = {Land dynamics, ecosystem resilience, and the interaction of management decisions with them vary significantly across space. One-size-fits-all applications across distinct land types have been responsible for many failures in rangeland management. Ecological Site Descriptions (ESDs) and similar land unit classification systems specify the characteristics of different land areas associated with variation in rangeland potential, ecological dynamics, vulnerabilities, and monitoring needs. State-and-transition models (STMs) embedded within ESDs specify the plant community phases, alternative states, and characteristics of thresholds observed within particular land areas. In spite of considerable conceptual advances with regard to general STM structure and mechanisms, strategies for data-driven development of ESDs and STMs have been poorly developed.}, keywords = {ecological side descritions, ESD, state-and-transition, STM}, author = {Brandon T Bestelmeyer and A.J. Tugel and G. Peacock and D. Robinett and D.D. Briske and T.K. Stringham and P. L. Shaver and Joel R. Brown and Jeffrey E. Herrick and H. Sanchez and Kris Havstad} } @conference {50165, title = {Social-biophysical feedbacks and land change in an arid rangeland region}, booktitle = {93rd Ecological Society of America Annual Meetings}, year = {2008}, month = {August 3, 2008}, pages = {PS 51-157}, address = {Milwaukee, WI}, abstract = {Studies of human-dominated ecosystems have traditionally externalized human agents and their behavior. Rangelands of the southwestern U.S. are no exception: in spite of century-long studies of vegetation change, the specific role of human decisions and their feedbacks with land condition are unknown. It is likely that prevention of future land degradation as well as opportunities for restoration will depend largely on our ability to manipulate these feedbacks. To support this perspective, we undertook a region-scale study of the relationships between the geophysical setting, land condition, and the history and current attributes of Bureau of Land Management (BLM) grazing allotments in south-central New Mexico. National Cooperative Soil Survey soil maps coupled to Ecological Site Descriptions were used to characterize the geophysical setting and inherent resilience, expert-supported, remote-sensed maps of vegetation states were used to characterize land condition, and BLM allotment records were used to characterize human dimensions variables including frequency of allotment turnover, the sense of impermanence, agency conflict, ranch type (trophy or dependent family) and management type (cautious vs. incautious). BLM allotment polygons were then attributed with human dimensions and geophysical/land condition data for analysis.}, keywords = {human, human-domiated, vegetationchange}, author = {Brandon T Bestelmeyer and R. K. Skaggs} } @conference {50164, title = {Teachers in the desert: Creating ecological reserech opportunities for teachres and students on the US Mexico border}, booktitle = {93rd Ecological Society of America Annual Meeting}, year = {2008}, month = {August 3-8, 2008}, pages = {OOS 17-8}, address = {Milwaukee, WI}, abstract = {Considerable research provides evidence for the value of teaching science using enhanced context strategies. These strategies include making learning relevant to students by using real-world examples and problems as well as taking students out of the classroom to learn about the topic. Unfortunately, these best practices are seldom used in the border region of southern New Mexico and west Texas due to a lack of funding, few teachers trained in inquiry-based science practices, and a lack of locally relevant curriculum. Ecological science here is often taught only from a textbook, a method that fails to demonstrate the excitement inherent in inquiry-based ecological science research. As part of the Teaching Ecological Complexity project funded by NSF, the Asombro Institute for Science Education and the Jornada Basin Long-Term Ecological Research Program conducted a two-week teacher professional development workshop in July 2008. High school teachers were immersed in their own ecological research projects, and they presented their hypotheses and results with the use of qualitative conceptual models. They also had opportunities to share and compare data collected by teachers and students at five other LTER sites. All workshop activities and research projects were correlated with state science and math education standards, making them instantly relevant and useful for teachers in the upcoming school year.}, keywords = {Asombro, student, teacher}, author = {Brandon T Bestelmeyer and R. Somerday} } @conference {50166, title = {Variation in ecological resilience: a fundamental concept for rangeland ecology}, booktitle = {Society for Range Management}, series = {Building Bridges: Grasslands to Rangelands}, year = {2008}, month = {Janury 26-31, 20}, pages = {1480}, address = {Louisville, KY}, abstract = {The concepts and terminology associated with ecological resilience are fast becoming a common language for the study of global change. We review the application of the broad concept of resilience to rangeland ecology, connecting it to several well-established rangeland concepts including equilibrial/nonequilibrial rangeland systems, ecological sites, succession, and state-and-transition models. We argue that resilience concepts have the potential to provide a holistic framework for rangeland ecology that links advances across disciplines including pedology, plant ecology, landscape ecology, rural sociology, and economics, and we illustrate this linkage. In order to realize this potential, however, we will need to move beyond vague metaphors to produce real-world examples and then general strategies that practitioners and scientists find worthwhile to emulate.}, keywords = {ecological, rangeland ecology, resilience}, author = {Brandon T Bestelmeyer and D.D. Briske and Joel R. Brown and Kris Havstad and R. K. Skaggs} } @conference {50167, title = {Vulnerability and triggers in threshold development: models from the Chihuahuan Desert}, booktitle = {Society for Range Management}, year = {2008}, month = {January 26-31, 2}, pages = {1487}, address = {Louisville, KY}, abstract = {We review models developed for the Draw and Loamy ecological sites in Major Land Resource Area 42.2 in southwestern New Mexico and review empirical support obtained for parts of the model. We describe evidence for 1) vulnerability to transitions and associated triggers and 2) the characteristics of alternative states. Remote-sensing based evidence supports the notion that fragmentation of grass cover creates vulnerability to transition, and anecdotal evidence supports the notion that high intensity storms serve as triggers that initiate erosion and gully formation. Field measurements indicate that degradation of soil structure, increased run-off, and reduced water infiltration are important feedbacks components driving the transition and reinforcing state changes. These relationships are strongly mediated by soil horizon development differences within the ecological site. The state-and-transition model thus links these scientific studies and provides indicators that can be used by managers to gauge the likelihood of threshold development.}, keywords = {threshold development}, author = {Brandon T Bestelmeyer and Jeffrey E. Herrick and Caitriana Steele} } @article {50313, title = {Does shrub invasion indirectly limit grass establishment via seedling herbivory? A test at grassland-shrubland ecotones}, journal = {Journal of Vegetation Science}, volume = {18}, year = {2007}, month = {March 1, 2007}, pages = {363-370}, abstract = {Does shrub invasion at ecotones indirectly limit grass establishment by increasing mammalian seedling herbivory, Chihuahuan Desert, New Mexico? We tested the hypothesis that herbivore-related mortality of seedlings of the dominant perennial grass Bouteloua eriopoda would be highest in shrub-dominated portions of grassland-shrubland ecotones. We tested the hypothesis in two Chihuahuan Desert sites featuring similar shrub encroachment patterns but different shrub species, grass cover, and different abundances of small mammals. Within each site we transplanted B. eriopoda seedlings to grass-dominated, middle, and shrub-dominated positions of replicate ecotones during the time of year (mid-summer) when they would naturally appear and monitored seedling fates. We estimated population size/activity of putative small mammal herbivores. Seedlings were killed by mammals in greater number in shrubland than in grassland or middle ecotone positions at the site withlarge herbivore numbers. At the site with low herbivore numbers, most seedlings were killed in middle ecotone positions. The abundance patterns of herbivores did not parallel patterns of seedling herbivory across the ecotones or between sites. Seedling herbivory is an improtant process and is related to vegetation composition, but the mechanisms underlying the relationship are not clear. We speculate that variation in small mammal foraging behvior may contribute to seedling herbivory patterns. Restoration strategies in the Chihuahuan Desert need to account for the abundance and/or behavior of native herbivores.}, keywords = {alternative state, Bouteloua eriopoda, Chihuahuan Desert, desertifiction, Dipodomys, foraging behavior, Lepus californicus, restoration, small mammal}, url = {/files/bibliography/07-005.pdf}, author = {Brandon T Bestelmeyer and Khalil, N.I. and Debra C. Peters} } @conference {50312, title = {Tipping points in rangelands: The scales of social-biophysical interactions}, booktitle = {Ecological Society of America Abstracts}, year = {2007}, note = {Duplicate of 215186. Use 215042 for reporting purposes}, month = {August 5-10, 200}, pages = {SYMP 2-7}, address = {San Jose, CA}, abstract = {Ecological and socio-economic processes are driving many of the world{\textquoteright}s rangelands beyond {\textquotedblleft}tipping points{\textquotedblright} to degraded states, but we have a poor understanding of the mechanisms by which these processes are linked to each other. We argue that this is due largely to the lack of data on region-scale patterns. We review three key concepts guiding our approach to investigating rangeland degradation at regional scales. First, a mechanistic understanding of tipping points must be based on understanding cross-scale relationships in pattern-process interactions. One insight is that the scales at which we should look for significant patterns/processes (e.g., those that explain variation in vegetation and soil degradation) vary with context and are often broader than we implicitly recognize. Second, transitions to degraded states are strongly conditioned by climo-edaphic heterogeneity. We are only beginning to identify and quantify the key attributes that govern transitions and know little about how climate change will modify those relationships. Finally, it is widely held that human behaviors underlie the approach to tipping points and loss of resilience, but we have little systematic understanding of how variations in behavior affect them. In the U.S., for example, spatial patterns of control of public grazing lands established under the Taylor Grazing Act, the adoption of more stringent rangeland oversight policies (e.g., the National Environmental Policy Act), and changing motivations of landowners may have large and unrecognized impacts on transitions. Improvements to the tools and policies we use to react to tipping points in rangelands will require broad-scale, social-ecological approaches that are still nascent.}, keywords = {socio-economic, tipping points}, author = {Brandon T Bestelmeyer and R. K. Skaggs and Debra C. Peters and Kris Havstad} } @article {50419, title = {Fragmentation Effects on Soil Aggregate Stability in a Patchy Arid Grassland}, journal = {Rangeland Ecology and Management}, volume = {59}, year = {2006}, month = {July 2006}, pages = {406-415}, abstract = {Soil aggregate stability (AS) has been promoted as a primary indicator of soil-surface function and a key metric in state-and-transition models. There are few studies, however, that relate indices of AS to the process of grassland degradation. In a Chihuahuan Desert rangeland, we measured variation in AS across vegetated-bare patch boundaries within six plot types reflecting a hypothesized fragmentation/transition sequence. We also examined wetting front depth and pH along this sequence. We found that AS exhibited consistent and interpretable variation across the patch boundaries of the different plot types. Average AS was highest in grass patches adjacent to small to medium-sized (0.5-1.5 m) bare patches and was low in grass patches adjacent to large (\> 3 m) bare patches. AS of bare ground was also lowest when bare patches in continuous grassland were large and when bare ground formed an interconnected matrix. Wetting depth after a large storm decreased and pH increased along the fragmentation sequence. The results suggest that AS has interpretable relationships with grassland fragmentation and transitions among states. Careful attention to patchiness within states and stratification, however, is important and simple classifications of strata, such as \“bare interspace\” and \“plant\”, may not be sufficient to document variation in soil function. http://www.bioone.org/perlserv/?request=get-pdf\&doi=10.2111\%2F05-180R1.1}, keywords = {aggregate stability, soil-surface, state-and-transition}, url = {/files/bibliography/06-027.pdf}, author = {Brandon T Bestelmeyer and J.P. Ward and Jeffrey E. Herrick and A.J. Tugel} } @inbook {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} } @conference {50418, title = {Managing Vegetation Dynamics: Soil-geomorphic Maps, State-and-Transition Models, and Remote Sensing}, booktitle = {2005 Ecological Society International Meeting, Ecological Society of America Abstracts}, year = {2006}, month = {January 2006}, pages = {133}, address = {Merida, Yucatan, MX}, abstract = {Vegetation mapping via remote sensing tools is a useful and cost-effective approach for understanding current land use and species habitat patterns, but has limited utility in predicting the future state of vegetation. We describe an approach that couples data-supported, conceptual state-and-transition models with soil-geomorphic mapping and remote sensing of vegetation states to provide maps of potential vegetation and their likely future state under different management scenarios. Soil maps are critical components of this approach that are often unattainable, so we describe an approach to classifying geomorphology-based land types based on landforms and remote-sensed imagery in arid to semiarid zones. The resulting maps reflect management hazards and opportunities for restoration that are not addressed in conventional vegetation maps.}, keywords = {patterns, sensing, soil-geomorphic, species habitat, vegetation}, author = {Brandon T Bestelmeyer and C. T. Monger and Fores Ancira, E. and Jeffrey E. Herrick and Caitriana Steele and Trevino, R.} } @article {50416, title = {A multi-scale classification of vegetation dynamics in arid lands: What is the right scale for models, monitoring, and restoration?}, journal = {Journal of Arid Environments}, volume = {65}, year = {2006}, month = {April 2006}, pages = {296-318}, abstract = {

Measurements of vegetation and soil dynamics used to anticipate (or reverse) catastrophic transitions in arid and semiarid rangelands are often difficult to interpret. This situation is due, in part, to a lack of empirically-based conceptual models that incorporate the effects of multiple processes, scale, spatio-temporal pattern, and soils. Using observations of multitemporal data from the Chihuahuan Desert, we describe a new approach to classifying vegetation dynamics based on multiple scales of vegetation and soil pattern as well as cross-scale interactions. We propose the existence of six types of mechanisms driving vegetation change including 1) stability, 2) size oscillation of plants, 3) loss and reestablishment of plants within functional groups, 4) loss of one plant functional group and replacement by another, 5) spatial reorganization of vegetation patches, and 6) cascading transitions that spread from small to broad scales. We provide evidence for the existence of these mechanisms, the species involved, and the geomorphic components on which they are observed in the Chihuahuan Desert. These mechanisms highlight the kinds of multi-scale observations that are needed to detect or interpret change and emphasize the importance of soil-surface properties for interpreting vegetation change. The classification is potentially general across arid and semiarid ecosystems and links spatial and temporal patterns in vegetation with ecological and geomorphic processes, monitoring, and restoration strategies.

}, keywords = {catastrophic, dynamics, measurements, multiple processes, scale, soil, spatiotermporal, transitions}, doi = {10.1016/j.jaridenv.2005.06.028}, url = {/files/bibliography/06-012.pdf}, author = {Brandon T Bestelmeyer and D. Trujillo and A.J. Tugel and Kris Havstad} } @article {50417, title = {Soil-Geomorphic Heterogeneity Governs Patchy Vegetation Dynamics at an Arid Ecotone}, journal = {Ecology}, volume = {87}, number = {4}, year = {2006}, month = {April 2006}, pages = {963-973}, abstract = {

Soil properties are well known to affect vegetation, but the role of soil heterogeneity in the patterning of vegetation dynamics is poorly documented. We asked whether the location of an ecotone separating grass-dominated and sparsely-vegetated areas reflected only historical variation in degradation or was related to variation in inherent soil properties. We then asked whether changes in the cover and spatial organization of vegetated and bare patches assessed using repeat aerial photography reflected self-organizing dynamics unrelated to soil variation or the stable patterning of soil variation. We found that the present-day ecotone was related to a shift from more weakly to more strongly developed soils. Parts of the ecotone were stable for over 60 year, but shifts between bare and vegetated states, as well as persistently vegetated and bare states, occurred largely in small (\<40 m2) patches throughout the study area. The probability that patches were presently vegetated or bare, as well as the probability that vegetation persisted and/or established over the 60 year period, was negatively related to surface calcium caronate and positively related to subsurface clay content. Thus, only a fraction of the landscape was susceptible to vegetation change and the sparesely-vegetated area likely featured a higher frequency of susceptible soil patches. Patch dynamics and self-organizing processes can be constrained by subtle (and often unrecognized) soil heterogeneity.

}, keywords = {autocorrelation, Chihuahuan Desert, patch dynamics, rangeland, self-organization, state-and-transition model, threshold}, doi = {10.1890/0012-9658(2006)87[963:SHGPVD]2.0.CO;2}, url = {/files/bibliography/06-015.pdf}, author = {Brandon T Bestelmeyer and J.P. Ward and Kris Havstad} } @proceedings {50414, title = {A three-tiered approach for coupled vegetation and soil sampling to develop ecological descriptions}, year = {2006}, month = {June 19-23, 2006}, abstract = {Ecological site descriptions (ESDs), alongside similar land classification systems, are used to describe the breadth of plant community types, community changes, and soil surface conditions that can occur within a particular land area. Vegetation dynamic processes and management may change the identity of plant communities over time, but there are a limited number of recognizable plant communities or vegetation states that are observed to occupy a given spatial position. Soil and climate variables are the key environmental attributes predicting the plant communities that can potentially occupy site. Consequently, soil survey products are tremendously useful for developing ESDs. Specifically, ecologically-similar soil map unit components are grouped to form ecological site classes. Soil maps can thus be used to anticipate the ecological sites and possible vegetation states present in a landscape. Ecological site descriptions have been developed by the NRCS alongside soil survey efforts and in soil survey updates. These efforts have resulted in the first generation of ESDs (formerly called range site descriptions). In spite of the great utility of these products, there are now a broader range of uses and users and increased scrutiny. Users have called for improvements in the clarity of classification criteria, increasing use and documentation of empirical data in developing classifications, and refinements to classifications in order accommodate state-and-transition models of vegetation dynamics. The latter issue is particularly important, as there is increasing evidence that the expression of vegetation dynamics and ecological thresholds may be governed by surprisingly subtle differences in soil properties that may or may not be distinguished in existing ESDs (e.g., Fuhlendorf and Smeins 1998, Bestelmeyer et al., 2006). Unfortunately, there are often few data available that can be used to investigate vegetation-soil relationships as a quantitative basis for producing or refining ESDs. The dearth of suitable data has many causes including 1) the lack of any vegetation data gathering associated with soil descriptions, 2) vegetation data that cannot be associated with soil pedon data, 3) too few samples of linked vegetation and soils to represent regional variation or to observe different vegetation states on the same soil types, 4)lack of geolocation and an inability to linked data to spatial layers such as modeled climate (e.g., Daly et al., 2002), 5) vegetation attributes are not sufficient to distinguish vegetation states or other important conditions, and 6) there are no data on surface soil attributes, and thus weak linkages to state-and-transition models and rangeland health. These limitations have precluded evaluation and refinement of ESDs by the science and management communities. In this presentation, we offer a comprehensive framework to overcome data limitations in the development of ESDs and other soil-vegetation-based land classification systems. The framework has four general components 1) training and employment vegetation/rangeland specialists who understand soils in soil survey and other efforts, 2) a set of vegetation sampling protocols that matches the pace of sampling in the field, 3) setting the goal of collecting data at many points with varying levels of precision rather than collecting data at a few points with unnecessarily high precision, and 4) systematic collection of data at georeferenced points and their storage in a database that links soil and vegetation properties. We provide details about these components and an example of how data can be used to generate inferences in an ESD context.}, keywords = {ecological descriptions, vegetation}, author = {Brandon T Bestelmeyer and A.J. Tugel and G. Peacock and H. Sanchez} } @article {50415, title = {Threshold Concepts and Their use in Rangeland Management and Restoration: The Good, The Bad and the Insidious}, journal = {Restoration Ecology}, volume = {14}, number = {3}, year = {2006}, month = {September 1, 200}, pages = {325-329}, chapter = {325}, abstract = {Ecological thresholds describe abrupt changes in ecological properties in time or space. In rangeland management, thresholds reflect changes in vegetation and soils that are expensive or impossible to reverse. The threshold concept has catalyzed important advances in rangeland management thinking, but it has also introduced two classes of drawbacks. First, the ambiguity of the term "threshold" and the desire for simplicity in its application has led to an over-emphasis on classification thresholds, such as vegetation cover values. Uncritical use of classification thresholds may lead to the abandonment of management efforts in land areas that would otherwise benefit from intervention. Second, it is possible that the invocation of thresholds and irreversible degradation may eventually result in the wholesale conversion of land areas that would have been recoverable or served important societal functions, such as biodiversity maintenance, that are not reflected in threshold definitions. I conclude with a recommendation to clarify the nature of thresholds by defining the relationships among pattern, process, and degradation and distinguishing preventive thresholds from restoration thresholds. We must also broaden the attributes used to define states and thresholds.}, keywords = {biodiversity, ecological thresholds, exurban development, grazing, landscape ecology, rangeland health, state-and-transition models, thresholds}, url = {/files/bibliography/06-030.pdf}, author = {Brandon T Bestelmeyer} } @article {50534, title = {Does desertification diminish biodiversity? Enhancement of ant diversity by shrub invasion in southwestern USA}, journal = {Diversity and Distributions}, volume = {11}, year = {2005}, month = {January 1, 2005}, pages = {45-55}, abstract = {

The conversion of desert grasslands to shrublands is a long-standing concern in the southwestern United States, but the effects of this change on native animals defy generalization. Here, I consider evidence that shrub invasion and encroachment, particularly that of honey mesquite (Prosopis glandulosa), has led to increasing ecological dominance and diversity of ants in general, as well as increases in specific native taxa. The effects of shrub invasion on ants were measured at two scales: (1) between Chihuahuan Desert landscapes that vary slightly in temperature and strongly in the dominance of mesquite, and (2) across variation in mesquite density occurring within a generally mesquite-dominated landscape. Ant richness and numerical dominance was measured at pitfall traps over 2 years and baits were used to assess ecological dominance across different temperatures. The mesquite-dominated Jornada site harbored four times the number of ant foragers found at the relatively \&$\#$39;pristine\&$\#$39; Sevilleta site with several ecologically-dominant taxa driving this pattern, especially Dorymyrmex bicolor. Species richness and ecological dominance was also greatest at the Jornada. Within the Jornada landscape, turnover in species composition was related to mesquite density, but local richness and abundance was unrelated to mesquite density. Coupled with the results of previous manipulative experiments and comparative studies, there is support for the notion that ant diversity is not negatively affected by shrub invasion but that several taxa prosper from it. The Jornada is uniquely saturated by dominant ant taxa, perhaps as a consequence of an overall high level of shrub availability that provides a reliable source of carbohydrate-rich plant exudates. This raises important questions about the relationship between environmental degradation, ecosystem productivity, and animal diversity.

}, doi = {10.1111/j.1366-9516.2005.00122.x}, url = {/files/bibliography/05-001.pdf}, author = {Brandon T Bestelmeyer} } @booklet {50533, title = {State and Transition Models 101: A Fresh Look at Vegetation Change}, howpublished = {Quivira Coalition Newsletter}, volume = {7}, number = {3}, year = {2005}, month = {August 3, 2005}, pages = {6-11}, abstract = {State-and-transition models are part of a new framework for evaluating the condition of rangelands, anticipating vegetation change, and planning land management. Government agencies, scientists, non-governmental organizations, and ranchers are involved in developing this framework. Why should you care? First, a clear understanding of vegetation change is critical. It lies at the center of the conflict (and cooperation) with which many of us are involved. It affects our bottom line, our interactions with others, and our ways of life. If you have ever wondered why vegetation has changed the way it has, what it used to look like, or what it could look like in the future, then you could probably use a state-and-transition model (hereafter, STM). Second. it is important to realize that both new scientific and policy developments will be connected to the concepts underlying STMs. Even an Undersecretary of the Interior Department and the director of the Bureau of Land Management (BLM) have publicly advocated the uses of STMs. The Nature Conservancy is also using STMs to prioritize conservation efforts. Alongside rangeland health, STM concepts will be part of the common language of natural resource management for years to come.}, keywords = {management, rangelands, state-and-transition, vegetation change}, url = {/files/bibliography/06-005.pdf}, author = {Brandon T Bestelmeyer and Joel R. Brown} } @conference {50631, title = {Applications of multi- and cross-scale analyses to management of dynamic systems}, booktitle = {Sixth Symposium on the Natural Resources of the Chihuahuan Desert Region}, year = {2004}, month = {October 15, 2004}, pages = {19}, address = {Alpine, TX}, abstract = {Decades of research on the management and monitoring of Chihuahuan Desert grasslands have emphasized (1) fine-scale patterns, (2) uniformity of dominant processes, and thus (3) standard, vegetation-based protocols for directing and measuring change. Although this was a necessary step, alone it is an insufficient approach to detecting and responding to degradation. We describe recent conceptual and empirical approaches to measuring the variety of pattern and process in vegetation transition based on soil-geomorphic-climate relationships, multiple scales of vegetation/soil pattern, and cross-scale interactions among grass loss in patches, patch connectivity and flux regulation, and climate-forcing functions. These approaches are being used to develop and refine tools that classify different pathways of vegetation response (state-and-transition models) according to soil and climate variables (ecological site descriptions). Pathways featuring cross-scale interactions can explain irreversible and nonlinear rates of change in time and space. These interactions indicate that different processes drive change at particular times and spatial locations, even within same vegetation type. Identification of the dominant processes governing vegetation change indicates the spatial pattern of change. In turn, this pattern indicates the appropriate scale and strategy for monitoring and designing and implementing management responses.}, keywords = {Chihuahuan Desert, climate, cross-scale, geomorphic, management, monitoring, multi-scale, soil, vegetation change}, author = {Brandon T Bestelmeyer and Jeffrey E. Herrick and Kris Havstad and E.L. Fredrickson and Joel R. Brown} } @proceedings {50635, title = {A general classification of vegetation dynamics for Chihuahuan Desert management models}, year = {2004}, month = {2004}, abstract = {We briefly describe a new conceptual approach to describing vegetation dynamics based on multiple scales of vegetation/soil pattern and processes and cross-scale interactions among grass loss in patches, patch connectivity and sediment/water flux regulation, and climate-forcing functions. This approach is based on a preliminary classification of transitions into five broad classes including: (1) size oscillation of grasses, (2) loss and recolonization of grasses, (3) loss of grasses with replacement by shrubs, (4) spatial reorganization of grass/shrub patches, and (5) cascading grass-shrub transitions that spread from small to broad scales. This classification links spatial and temporal patterns with ecological processes and monitoring strategies.}, author = {Brandon T Bestelmeyer and Jeffrey E. Herrick and Kris Havstad and Joel R. Brown} } @article {50637, title = {Land management in the American Southwest: A state-and-transition approach to ecosystem complexity}, journal = {Environmental Management}, volume = {34}, number = {1}, year = {2004}, month = {July 1, 2004}, pages = {38-51}, abstract = {

State-and-transition models are increasingly being used to guide rangeland management. These models provide a relatively simple, management-oriented way to classify land condition (state) and to describe the factors that might cause a shift to another state (a transition). There are many formulations of state-and-transition models in the literature. The version we endorse does not adhere to any particular generalities about ecosystem dynamics, but it includes consideration of several kinds of dynamics and management response to them. In contrast to previous uses of state-and-transition models, we propose that models can, at present, be most effectively used to specify and qualitatively compare the relative benefits and potential risks of different management actions (e.g., fire and grazing) and other factors (e.g., invasive species and climate change) on specified areas of land. High spatial and temporal variability and complex interactions preclude the meaningful use of general quantitative models. Forecasts can be made on a case-by-case basis by interpreting qualitative and quantitative indicators, historical data, and spatially structured monitoring data based on conceptual models. We illustrate how science- based conceptual models are created using several rangeland examples that vary in complexity. In doing so, we illustrate the implications of designating plant communities and states in models, accounting for varying scales of pattern in vegetation and soils, interpreting the presence of plant communities on different soils and dealing with our uncertainty about how those communities were assembled and how they will change in the future. We conclude with observations about how models have helped to improve management decision-making.

}, keywords = {Chihuahuan Desert, community dynamics, desert grassland, grazing management, rangeland, resilience, simulation models, soil maps, thresholds}, doi = {10.1007/s00267-004-0047-4 }, url = {/files/bibliography/04-015.pdf}, author = {Brandon T Bestelmeyer and Joel R. Brown and Jeffrey E. Herrick and D. Trujillo and Kris Havstad} } @conference {50636, title = {Managing land using ecological processes}, booktitle = {3rd Annual Conference, Quivira Coalition}, year = {2004}, month = {January 15-17, 2}, pages = {18-19}, address = {Albuquerque, NM}, abstract = {Ranching in nature{\textquoteright}s image requires not only an understanding of what ecological processes may be important, but also a well-developed working knowledge of how those processes occur in space and time. While the scientific and ranching communities have devoted much attention to describing and managing important ecological processes like energy flow, nutrient transformation and cycling, water cycling, seed dispersal, etc., we have not spent a great deal of effort putting these processes into a management context with clear links to on-the-ground decision making. In this session, we will cover three important concepts that serve as a framework for interpreting information about ecological processes and suggest a means of organizing and, more importantly, testing whether management actions are having the desired effects. First, we will discuss the importance of variability in space and time when interpreting general or site-specific information for management decisions. For instance, rainfall infiltration rate is a good indicator of plant community and soil health. However, the rate of infiltration can vary dramatically within a paddock, within a plant community or even around an individual plant even though the entire area is subject to the same management and may be described as the same soil or the same ecological site. Knowing where and when to gather information about ecological processes is a critical component of management planning and effective monitoring. Second, the concepts of resistance and resilience are fundamental to interpreting ecosystem behavior and making management decisions designed to achieve goals and objectives. Resistance is the degree of disturbance (for instance, grazing) a plant community or soil can tolerate before it changes to another state. Resilience is the time it takes for a plant community or soil to return to its original state when the disturbance (for example, drought) is suspended. A qualitative understanding of resistance and resilience for specific sites is fundamental for making effective decisions about management and interpreting monitoring data. Finally, we will discuss the importance of ecological thresholds in managing grazing lands. Ecological thresholds can be viewed as critical periods in time when plant community and soil processes undergo significant and persistent changes in response to particular management or natural factors. Such changes are common when resistance and resilience are compromised. Once processes have changed and a new state is indicated, there is a very low probability that the community/soil will return to its original state without costly management intervention. Management models and monitoring systems must be designed with ecological thresholds in mind. The concepts of spatial and temporal variability, ecosystem resistance and resilience, and ecological thresholds can be combined to interpret information about ecological patterns and processes occurring in a ranch. While these concepts are general, the complexity of landscapes precludes the development of general, management-oriented mathematical models of rangeland behavior. Site-specific application of the concepts is a key component of effective and successful range management.}, author = {Brandon T Bestelmeyer and Joel R. Brown and Kris Havstad and S. Tartowski} } @conference {50633, title = {Region-wide empirical testing of state-and-transition models}, booktitle = {57th Annual Meeting of Society for Range Management}, year = {2004}, month = {January 25-30, 2}, pages = {Abstract No. 31}, address = {Salt Lake City, UT}, abstract = {Conceptual state-and-transition models for southern New Mexico were developed from literature reviews and expert opinion. These models describe patterns and causes of succession and persistent transitions in vegetation for particular ecological sites (groups of soil types), as well as indicators of the mechanisms underlying those dynamics. Propositions in state-and-transition models are difficult to test because vegetation transitions and patterns of resilience are expressed over decades in semiarid environments and because valid tests must be conducted at regional scales. We are using long-term (up to 35 yr) trend-plot photographic records and other sources of repeat photography from throughout southern New Mexico, coupled with detailed soil and landscape characterization to evaluate several predictions arising from state-and-transition models. We report evidence that (1) vegetation on fine-textured and shallow, skeletal soils is comparatively resistant and resilient, while that on fine to coarse loamy soils continues to undergo transitions, (2) transitions may be caused by contagious processes, such as sand deposition from adjacent sites, that depend on landscape context rather than local management, (3) encroaching shrub species that are featured in current state-and-transition models may not be the shrub species that will cause future transitions, and (4) subtle variations in regional climate and soil properties may have a greater impact on the probability of transition than was previously recognized. We discuss the general problem of using localized historical studies to generate region-scale forecasts in rangelands.}, author = {Brandon T Bestelmeyer and Joel R. Brown and Kris Havstad and D. Trujillo} } @conference {50634, title = {Scales of pattern and process in the management of the Chihuahuan Desert biodiversity}, booktitle = {11th Annual Conference, The Wildlife Society}, year = {2004}, month = {September 18-22,}, address = {Calgary, Alberta, Canada}, abstract = {In the Chihuahuan Desert concern about both the loss of biodiversity and economic productivity centers on the loss of grasslands and their transition to shrublands (i.e., desertification). Decades of research on this process have emphasized relatively fine scales. Although this was a necessary step, alone it is insufficient to explain instances and broader patterns of change. Furthermore, these processes have been only tenuously linked to biodiversity. We describe recent conceptual and empirical approaches to describing the process of transition based on cross-scale interactions between grass-shrub relationships and losses of grass in patches, between-patch connectivity and interactions with climate forcing functions, and landscape to regional-level feedbacks to climate. These processes create nonlinear changes in time and space such that different processes are important at particular times and spatial locations. This notion has important implications for monitoring and management. The variety of dynamics and patterns in vegetation and soils these processes create drive spatial and temporal variation in biodiversity. We discuss ongoing work to link ecosystem models to biodiversity data and to integrate management strategies based on rangeland and wildlife concerns.}, keywords = {approaches, biodiversity, Chihuahuan Desert, cross-scale}, author = {Brandon T Bestelmeyer and Debra C. Peters and Kris Havstad} } @conference {50632, title = {Soil-geomorphic basis of divergent landscape trajectories in the Chihuahuan Desert}, booktitle = {89th Annual Meeting, Ecological Society of America}, year = {2004}, month = {August 1, 2004}, pages = {p. 45}, address = {Portland, OR}, abstract = {A major emphasis of rangeland ecology and management is to understand the factors that regulate rates of vegetation and soil change. Explanations of change have traditionally ignored subtle soil heterogeneity and emphasized single processes. We sought to employ a multiscale, multifactor framework to interpret variability in rates of vegetation change occurring within a Chihuahuan Desert grassland under similar management. We used a combination of ground-based measures and remote-sensed data from 1936 and 1996 to construct a scenario explaining different rates of grass loss in two adjacent grassland areas on a piedmont slope. The two areas now merge at sharp ecotone separating a high-grass, low-shrub cover state and a state with lowgrass, high-shrub, and high-bare ground cover. The basis for these divergent trajectories is related to differences in the spatial pattern of soil calcium carbonate content and argillic horizon development. Where high carbonate soils with weak argillic horizons are relatively continuous, single-crown and stoloniferous grasses dominate at the expense of a rhizomatous grass. Grazing appears to have contributed to higher connectivity of bare ground where single-crown grasses predominated, leading to increased susceptibility to erosion, lower soil aggregate stability, lower rainfall infiltration, and soil truncation leading to accelerated rates of grass and shrub mortality. Under these conditions, grass and shrub cover are positively correlated at fine scales even when they are negatively correlated at a broad scale. Eroded soil accumulates on the highgrass side of the ecotone, contributing to ecotone contrast. This example illustrates the need for multiscale perspectives in explaining ecosystem resistance and resilience.}, keywords = {Chihuahuan Desert, ecology, management, rangeland, vegetation and soil change}, author = {Brandon T Bestelmeyer and J.P. Ward and Jeffrey E. Herrick and A.J. Tugel} } @conference {50744, title = {Ants and termites: The little things that run your ranch}, booktitle = {56th Annual Meeting, Society for Range Management}, year = {2003}, month = {February 1-6, 20}, address = {Casper, WY}, abstract = {Ants and termites are very abundant, active, and species-rich animal groups in rangelands. One can hardly take a step without seeing evidence of their presence. As a consequence, these animals are intimately tied to many parts of rangeland functioning. The burrowing activities of ants and termites can be critical to maintaining soil quality and infiltration in the short-term and soil development over the long-term. These animals also have important effects on nutrient transport, retention, and availability in soils. The many species of inconspicuous, scavenging ants are largely responsible for removing dead animal matter into the soil. Where termites are abundant, their consumption of dead plant material may regulate, and actually decrease, the amount of organic matter in soils. But, ants and termites are also reservoirs of nutrients such as nitrogen and phosphorus. These nutrients are stored in their bodies and are released during nuptial flights after rains at points in time when they can be rapidly incorporated by other life forms. Ants are also important consumers of seeds and plants. Thus, the activities of ants and termites directly and indirectly affect plant production as well as the diversity of other rangeland organisms. Luckily, ants and termites are forgiving animal groups with respect to current and historical overgrazing in many rangelands. Nonetheless, observing the activities of these groups and understanding their significance can aid in gauging the health of rangelands as well as enjoying them.}, author = {Brandon T Bestelmeyer and Walter G. Whitford} } @article {50749, title = {Applying species diversity theory to land management}, journal = {Ecological Applications}, volume = {13}, number = {6}, year = {2003}, month = {December 1, 2003}, pages = {1750-1761}, abstract = {

Many theories and hypotheses have been proposed to explain patterns of species diversity and distribution/abundance at particular scales, but they are often unclear on how these ideas relate or how they apply across multiple scales. It has been difficult to use diversity theory to understand patterns at the intermediate scales at which biodiversity is managed. Here, we present a framework for studying diversity based on the ecological processes influencing distribution of organisms at different scales. We use this framework to organize diversity theories into several classes. The framework highlights that processes contributing to diversity patterns depend on the characteristics of the taxa considered, the spatial scales at which organisms respond to environment, and the scales and other characteristics of the particular environments in which investigators hope to explain variation in diversity. At the scales traditionally considered by land managers and conservation biologists, biodiversity is determined b the interactions among habitat occupancy, landscape distribution, and geographic range for a variety of taxa. The framework suggests that, in each case, managers should address the following general questions: 1) which groups of organisms will be considered, 2) how do their domains of scale relate to the land area under consideration, 3) what processes are likely to be important determinants of species distribution at management scales, and 4) how will the proposed management activities interact with these processes? We emphasize the value of considering species diversity theories in a pluralistic and case-specific way, rather than seeking singular explanations or "general laws" explaining diversity variations.

}, keywords = {Chihuahuan Desert, competition, conservation, dispersal, land management, landscape ecology, limitation geographic, macroecology, natural resources management, range habitat, Selection, species diversity}, doi = {10.1890/02-5089}, url = {files/bibliography/JRN00376.pdf}, author = {Brandon T Bestelmeyer and J.R. Miller and J.A. Wiens} } @article {50751, title = {Development and use of state-and-transition models for rangelands}, journal = {Journal of Range Management}, volume = {56}, number = {2}, year = {2003}, month = {March 1, 2003}, pages = {114-126}, abstract = {

State-and-transition models have received a great deal of attention since introduction of the to range management concept in 1989. Recently, sets of state-and-transition models have been produced that can be used by agency personnel and private citizens, but there is little guidance available for developing and interpreting models. Thus, we address the following questions: 1) how is information assembled to create site-specific models for entire regions, 2) how are models constructed, 3) what are the challenges to their validity, and 4) how should models be used? We review the general structure of state-and-transition models, emphasizing the distinction between the easily-reversible changes among communities within states and the more persistent, threshold behavior of changes among states (transitions). Both succession and transitions occur, so these models are complementary. Ecological sites serve as a framework for developing and selecting models. We illustrate the importance of clearly delineating ecological sites to produce models and describe how we have dealt with poorly-delineated sites. Producing specific models requires an understanding of ecological mechanisms underlying transitions. Mechanisms tend to fall within discrete categories based upon fundamental ecological processes and their relationships are readily understood. A knowledge of mechanisms is related to the use of ecological indicators to anticipate thresholds. We conclude models should include 1) reference values for quantitative indicators, 2) lists of key indicators and descriptions of changes suggesting an approach to a threshold, and 3) a rigorous documentation of the theory and assumptions (and their alternatives) underlying the structure of each model.

}, url = {/files/bibliography/03-006.pdf}, author = {Brandon T Bestelmeyer and Joel R. Brown and Kris Havstad and Alexander, R. and Chavez, G. and Jeffrey E. Herrick} } @conference {50747, title = {A field guide to land: User-friendly interpretations of rangeland communities}, booktitle = {Second National Conference on Grazing Lands}, year = {2003}, month = {December 7-10, 2}, address = {Nashville, TN}, abstract = {The Ecological Site Descriptions (ESDs) of the USDA Natural Resources Conservation Service are a series of publically-available reports that provide interpretations of plant community composition and change that are based on climate, soil development, surface soil characteristics and fertility, and competition and disturbance to key plant species. A single ESD report is associated with several soil series occurring within climatic region. These reports can be used to help evaluate questions about land condition, such as: why is there so little black grama (Bouteloua eriopoda) on this site? The answer will be different depending on the location and history of the site: the climate may be too wet or the soil too clayey to support much black grama; black grama may have been abundant but was reduced due to historical degradation of the soil; or black grama has recently declined due to heavy grazing or drought, but can recover its former abundance. Choosing the right answer is critical for identifying real management options and avoiding needless controversy. ESDs are increasingly able to assist the analysis of plant and soil patterns but are difficult for the public to use. We provide an example and format for user-friendly versions of ESDs that features a range of decision support tools, including a series of keys and supplemental photographs, to guide interpretations of land condition in defined geographic areas.}, author = {Brandon T Bestelmeyer and Chavez, G. and Joel R. Brown and D. Trujillo} } @proceedings {50750, title = {Future directions in soil-vegetation descriptions: Systematizing dynamics}, year = {2003}, month = {June 16-20, 2003}, pages = {35-36}, address = {Plymouth, MA}, abstract = {State-and-transition models are being used to describe the coupled plant-soil dynamics in ecological site descriptions. Major challenges in producing these models include 1) distinguishing transient dynamics from changes persistent (and significant) enough to qualify as {\textquoteright}transitions{\textquoteright} as recently defined; 2) distinguishing true, self-reinforcing transitions from {\textquoteright}pseudo-transitions{\textquoteright} caused by persistent perturbation of a system due to continuous heavy grazing, for example, and that will return to the original state once the perturbation ceases; and 3) isolating present-day spatial heterogeneity within ecological sites that is attributable to transient or threshold dynamics from static patterns caused by differences among the soils grouped within ecological sites. If we are to foster a science-based understanding of rangeland ecosystems using ESDs, we must carefully consider how we treat these phenomena in models. We briefly review these challenges.}, author = {Brandon T Bestelmeyer and Joel R. Brown} } @proceedings {50746, title = {Grazing in complex environments: The details matter}, year = {2003}, month = {January 18-19, 2}, pages = {1-6}, address = {Albuquerque, NM}, abstract = {Rangeland ecosystems are complex environments. Their physical, biological, economic, and social elements are driven by thousands of variables with millions, if not billions, of interactions. Because our understanding of these systems is incomplete, at best, it has been very difficult to develop predictive models with sufficient precision to describe how these systems will behave in response to management. Within this setting, livestock grazing is a reasonable use on many rangelands, although it may not be appropriate in some environments. The sustainability of livestock grazing in western rangeland environments is dependent upon appropriate management of this activity and requires an understanding of the basic workings of these ecosystems{\textquestiondown}of key processes related to soils, plants, and animals. These processes vary with different environments, conditions, annual cycles, histories, production inputs, and other factors. Many of these considerations are subject to variations in space and time. Not all landscapes can be managed alike; good grazing management requires close attention to the details. In order to manage grazing in a truly adaptive and sustainable manner, we need to be able to recognize what is present in a given system, to understand what is possible for that system, and to monitor our effects.}, url = {http://quiviracoalition.org/Detailed/On-Line_Store/Conference...dings/The_New_Ranch_at_Work_198.html}, author = {Brandon T Bestelmeyer and Joel R. Brown and Kris Havstad} } @article {50748, title = {Scavenging ant foraging behavior and variation in the scale of nutrient redistribution in semiarid grasslands}, journal = {Journal of Arid Environments}, volume = {53}, number = {3}, year = {2003}, month = {March 1, 2003}, pages = {373-386}, abstract = {The scavenging of arthropod carrion by ants is an important mechanism of nutrient redistribution in grasslands. But, the foraging activities of scavenging ants have been scarcely documented. We examine variation in overall ant foraging activity among grassland regions differing in species composition and how this creates differences in the distances that scavenged material is redistributed among three semiarid grassland ecosystems. In order to consider the effects of the ant community as a whole on the disposition of nutrient resources, we focused on the fate of baits that appeared under different environmental conditions. Specifically, we asked 1) which ant species are the dominant scavengers in each grassland, 2) what ant characteristics determine the distance that baits are removed to nests, and 3) how do these patterns come together to create differences among grassland ecosystems in the distance that scavenged resources are removed? Species at a site differed widely in the microclimatic conditions that they removed baits and in the average distances they were removed. Generally, species with large-bodied workers and thermophilic species removed baits the farthest. Overall, this resulted in a positive relationship between removal distance and vapor pressure deficit (VPD). Controlling for intersite variation in habitat types and VPD, mean removal distance across all ants increased from the shortgrass steppe to the Chihuahuan Desert grassland. We conclude that differences in the foraging ecology and body size of the dominant scavengers among these grasslands can create a seven-fold variation in the spatial scale of nutrient concentration by ants. These species are little-known when compared to the harvester ants emphasized in ecosystem studies.}, url = {/files/bibliography/03-005.pdf}, author = {Brandon T Bestelmeyer and J.A. Wiens} } @conference {50743, title = {Using state-and-transition models: Tools for prophylaxis, diagnosis, or autopsy?}, booktitle = {56th Annual Meeting of Society for Range Management}, year = {2003}, month = {February 1, 2003}, pages = {16}, address = {Casper, Wyoming}, abstract = {As range managers and ecologists proceed with creating state-and-transition models, it is important to ask how they can be used to maintain rangeland health. We explore this question by examining how the Bureau of Land Management has used models, and by considering field studies of transitions in New Mexico. Models are often used in a {\textquoteright}post-mortem{\textquoteright} fashion to explain the existence of degraded states. It is difficult, however, to identify the ultimate causes of degradation. Another challenge is to identify indicators in models that can be used to alert managers to the initial stages of degradation and to guide management changes. This difficulty is illustrated by cases in which healthy-looking landscapes degrade without continued human impacts. In other cases, landscapes that exhibit clear warnings of an impending transition recover without grazing adjustments. A promising use of state-and-transition models is to illustrate how within- and among site variability in topography and inherent soil properties (e.g. texture and depth) predispose sites to transitions. In this application, emphasis is placed on the relative risks of an undesired transition associated with landscape position, soil properties and regional climate characteristics. Unrecorded, unpredictable, and interacting variables (such as climate and species introductions) restrict our ability to correctly interpret and predict transitions. Nonetheless, state-and-transition models provide a basis for prediction, management action, and tests of concepts. We will discuss research approaches to addressing the various uses of state-and-transition models.}, author = {Brandon T Bestelmeyer and Joel R. Brown and Jeffrey E. Herrick and Phil Smith and Kris Havstad} } @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} } @conference {50839, title = {Soil and spatial dependence of landscape dynamics in Chihuahuan Desert grasslands}, booktitle = {17th Annual Symposium, US-International Association for Landscape Ecology}, year = {2002}, month = {April 23-26, 200}, pages = {64}, address = {Lincoln, NE}, abstract = {It is clear that soil properties, landscape position, and nutrient transfers among landscape elements affect the properties of plant communities. Nonetheless, few studies have attempted to account for these variables in explaining plant community dynamics. We examine how changes in grass cover, grass patch structure, and shrub abundance varied on different soils within the southern Jornada del Muerto Basin of New Mexico, USA. Changes in vegetation patterns revealed by repeat photography over 30-40 years (from 1959-2001) were related to detailed measurements of soil properties and geomorphology taken at each photography site as part of the Desert Soil-Geomorphology Project of the Natural Resources Conservation Service. On heavy soils on basin floor or lower piedmont positions, grass patch structure was remarkably stable or patch size increased over the study period. Shrub abundance increased little or even declined. On loamy to sandy soils on upper piedmont positions that were not already devoid of grass, grass cover has declined and shrub abundance and size increased. It is likely that the translocation of water and other resources from degrading sites on upper fan piedmont positions lead to the stability or increases in grass cover observed in downslope landscape positions. These patterns indicate that interpretations of rangeland degradation must account for soils, geomorphology and landscape connectivity.}, author = {Brandon T Bestelmeyer and L. H. Gile and B. Nolen and Curtis H. Monger and Kris Havstad} } @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} } @article {50969, title = {Ant biodiversity in semiarid landscape mosaics: The consequences of grazing vs. natural heterogeneity}, journal = {Ecological Applications}, volume = {11}, number = {4}, year = {2001}, month = {August 1, 2001}, pages = {1123-1140}, abstract = {

Conservation of biodiversity in landscape mosaics requires us to understand the impacts of human land use within mosaic elements and an evaluation of the biological uniqueness of different elements. We examined patterns of ant diversity in three semiarid rangeland landscapes used predominantly for grazing. Within each landscape, we compared the effects of grazing and natural variation in soils and vegetation on ant diversity and community composition. Grazing had little effect on ant richness, diversity, or composition at the transitional zone or the desert grassland site; but, ungrazed areas at the shortgrass steppe site had a higher overall richness and favored the abundance of some species. Some samples of saltbush (Atriplex canescens) shrubland were similar to ungrazed samples in richness and species composition. In both the transitional zone and the desert grassland, creosotebush (Larrea tridentata)-dominated habitats harbored comparatively species-rich and distinct ant communities. Also, mesquite (Prosopis glandulosa) coppice dunes at the desert grassland site favored the abundance of several rare species. Canonical correspondence analysis revealed that variation in soil hardness and texture best explained community variation at the shortgrass steppe site, whereas soil texture and associated differences in shrub density best explained differences in composition at the transitional and desert grassland sites. While habitat characterization based on vegetation classification did not adequately reflect environmental variation important to ants in shortgrass steppe, it reflected important soil textural variation in the transitional and desert grassland sites. This suggests that ant conservation in these semiarid rangelands should emphasize patterns of variation in soil properties.

}, keywords = {ants, canonical correspondence analysis, desert grassland, diversity, formicidae, grazing, habitat classification, shortgrass steppe, soil texture}, doi = {10.1890/1051-0761(2001)011[1123:ABISLM]2.0.CO;2}, url = {/files/bibliography/01-014.pdf}, author = {Brandon T Bestelmeyer and J.A. Wiens} } @proceedings {50971, title = {An approach to managing landscape pattern and dynamics in southern New Mexico}, year = {2001}, month = {April 1, 2001}, address = {Las Cruces, NM}, abstract = {The ecological site concept of USDA Natural Resource Conservation Service provides a hierarchical framework for classifying and distinguishing landscape units differing in the processes that determine plant and animal community dynamics within units and that determine interactions among units. Ecological sites are based upon important differences in landscape position and inherent soil properties as defined by the responses of dominant plant species to variation in climate and management. Dominant plants, in turn, regulate several ecosystem attributes including dynamic soil properties. State-and-transition models represent theories about the positive feedbacks between plants and ecosystems and the causes of irreversible changes in plant and animal composition. An understanding of these causes is needed to avoid ecosystem degradation, to fairly evaluate and manage instances of degradation, and to promote remediation. Here, we describe our ongoing efforts to improve the ecological site classification system for the Chihuahuan Desert of southern New Mexico by integrating current approaches to community and landscape ecology with the historical perspective and practical experiences of land managers and ranchers. Our approach emphasizes an increased understanding of patterns of dispersal, establishment, and growth of dominant plants along landscape and climatic gradients.}, keywords = {classifying, dynamics, ecological site concept, landscape pattern, landscape units, management}, url = {http://agecon.nmsu.edu/nmsrm/}, author = {Brandon T Bestelmeyer and Joel R. Brown and Kris Havstad and Alexander, R. and Chavez, G. and Jeffrey E. Herrick} } @booklet {50973, title = {Buffelgrass invasion: What is the value of a desert?}, howpublished = {Chihuahuan Desert Nature Park Newsletter}, year = {2001}, month = {April 1, 2001}, pages = {1}, abstract = {This popular article summarizes the reasons why buffelgrass (Cenchrus ciliaris=Pennisetum ciliare) may threaten biodiversity in southern desert areas. This presents an interesting problem when you consider that this grass can be used to improve forage production and reduce erosion. Unfortunately, buffelgrass also introduces fire to areas in which this disturbance has not been common (at least in recent history). This proces can result in the transformation of species-rich shrublands to species-impoverished buffelgrass monocultures. More research is needed to evaluate the costs and benefits of buffelgrass cultivation.}, keywords = {buffelgrass, desert, invasion, value}, author = {Brandon T Bestelmeyer} } @conference {50972, title = {Developing and applying state-and-transition models to manage rangelands}, booktitle = {86th Annual Meeting, Ecological Society of America}, year = {2001}, month = {August 5-10, 200}, pages = {7}, address = {Madison, WI}, abstract = {State-and-transition models represent theories about the causes of threshold changes between ecosystem types in response to temporal changes in land use and/or climate. In contrast to the quantitative climax model that views ecosystem change as gradual and reversible, the state-and-transition concept holds that disturbances catalyze a shift in positive feedbacks between plants and ecosystem properties, such as nutrient availability and erosion potential, that may lead to irreversible changes in plant and animal composition. Applying this concept to rangeland management will require attention to the processes underlying threshold changes in varying contexts. We propose a set of standard definitions and a format for displaying individual state-and-transition models. We discuss how various sources of information on the processes underlying plant community pattern and dynamics can be brought together to develop predictive state-and-transition models. We argue the utility of models depends critically upon 1) the identification of appropriate spatial and temporal scales for measurement and management, 2) the identification of appropriate windows of climatic, topographic, and soil conditions within which systems behave similarly and that serve as a basis for model classification, 3) the recognition of system openness to landscape influences, and 4) acknowledgment of the case-contingent operation of different mechanisms. We illustrate how insights from community and landscape ecology can be blended with the historical perspective and practical experiences of land managers to build models.}, author = {Brandon T Bestelmeyer and T.K. Stringham and Joel R. Brown and Kris Havstad} } @conference {50970, title = {An integrated approach to managing landscape pattern and dynamics in southern New Mexico}, booktitle = {16th Annual Symposium, US-International Association for Landscape Ecology Meeting}, year = {2001}, month = {April 25-29, 200}, pages = {29}, address = {Tempe, AZ}, abstract = {The ecological site concept of USDA Natural Resource Conservation Service provides a hierarchical framework for classifying and distinguishing landscape units differing in the processes that determine plant and animal community dynamics within units and interactions among units. Ecological sites are based upon important differences in landscape position and inherent soil properties as defined by the responses of dominant plant species to variation in climate and management. Dominant plants, in turn, regulate several ecosystem attributes, including dynamic soil properties. State-and-transition models represent theories about the positive feedback between plants and ecosystems and the causes of irreversible changes in plant and animal composition. An understanding of these causes is needed to avoid ecosystem degradation, to fairly evaluate and manage instances of degradation, and to promote remediation. Here, we describe our ongoing efforts to improve the ecological site classification system for the Chihuahuan Desert of southern New Mexico by integrating current approaches to community and landscape ecology with the historical perspective and practical experiences of land managers and ranchers. Our approach emphasizes an increased understanding of patterns of dispersal, establishment, and growth of dominant plants along landscape and climatic gradients.}, author = {Brandon T Bestelmeyer and Joel R. Brown and Kris Havstad and Alexander, R. and Chavez, G. and Jeffrey E. Herrick} } @article {50974, title = {Local and regional-scale responses of ant diversity to a semiarid biome transition}, journal = {Ecography}, volume = {24}, number = {4}, year = {2001}, month = {December 1, 2001}, pages = {381-392}, abstract = {

The locations of biome transitions and ecotones are frequently defined by the rapid shift from one form of dominant vegetation to another. The composition of animal taxa is predicted to shift parallel with that of dominant plants, and species diversity is predicted to be greater in transitional zones than in adjacent areas. We asked whether ant species diversity and composition supported these predictions across a biome transition between shortgrass steppe and Chihuahuan Desert vegetation. Neither species richness nor diversity was highest at the biome transition region as a whole or within habitats in the biome transition. The biome transition region was not intermediate in ant species composition or in the representation of different faunal complexes. The community similarity between matched habitats shared between the biome transition zone and adjacent regions was less than that between distinct habitats occurring within regions. A zoogeographic transition for ants may occur to the nort of the phytogeographic transition and may be coincident with the northern limits of monsoonal precipitation patterns. In contrast, the phytogeographic transition may be related to less extreme climatic variation within the monsoonal region occurring further south.

}, keywords = {ants, Desert insects, grasslands, Habitats, Insect communities, shrublands, species diversity, Steppes, Taxa}, doi = {10.1034/j.1600-0587.2001.d01-194.x}, url = {/files/bibliography/01-015.pdf}, author = {Brandon T Bestelmeyer and J.A. Wiens} }