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The following articles were lead or co-authored by Dr. Bestelmeyer, Research Ecologist at USDA-ARS, Jornada Experimental Range.

Description

My work addresses the causes and management implications of ecosystem dynamics in drylands and other ecological systems. I study processes at several spatial scales as a basis for understanding the formation and maintenance of alternative ecosystem states. I link research to management applications including “ecological site” land classifications, assessment and monitoring tools, and evaluations of restoration effects. This work has involved measurements and analysis of plant and animal community pattern and dynamics, plant growth/reproduction, characterization of soil surface and soil profile properties, mapping of vegetation, and social-ecological system perspectives. Applications are focused on US land management agencies and institutions in Mongolia, China, and Argentina.

latest article added on January 2015

ArticleFirst AuthorPublished
Scavenging ant foraging behavior and variation in the scale of nutrient redistribution among semi-arid grasslandsBestelmeyer, BT2003

Scavenging ant foraging behavior and variation in the scale of nutrient redistribution among semi-arid grasslands

Keywords

ants; desert grassland; ecosystem function; foraging; Formicidae; microclimate; scavenging; shortgrass steppe; vapor pressure deficit

Abstract

The scavenging of arthropod carrion by ants can be an important mechanism of nutrient redistribution in grasslands. By removing materials to nests over different sized areas, scavenging ants may contribute to differences in ecosystem patchiness. We asked how variation in overall ant foraging activity among three desert/grassland Long-Term Ecological Research sites creates differences in the distances that scavenged material is laterally redistributed. 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. Mean removal distance across all ants increased from the shortgrass steppe to the Chihuahuan desert grassland, creating a seven-fold variation in the spatial scale of nutrient concentration by ants. The dominant species creating this pattern are inconspicuous and little-known when compared to the harvester ants that have been emphasized in ecosystem studies. (C) 2002 Elsevier Science Ltd.

Authors

Bestelmeyer, BT; Wiens, JA

Year Published

2003

Publication

Journal of Arid Environments

Locations
DOI

10.1006/jare.2002.1044

Spatiotemporal Patterns of Production Can Be Used to Detect State Change Across an Arid LandscapeWilliamson, Jeb C.2012

Spatiotemporal Patterns of Production Can Be Used to Detect State Change Across an Arid Landscape

Keywords

aboveground net primary production; normalized difference vegetation index; precipitation; remote sensing; Chihuahuan Desert; state change; shrub encroachment; grassland; shrubland

Abstract

Methods to detect and quantify shifts in the state of ecosystems are increasingly important as global change drivers push more systems toward thresholds of change. Temporal relationships between precipitation and aboveground net primary production (ANPP) have been studied extensively in arid and semiarid ecosystems, but rarely has spatial variation in these relationships been investigated at a landscape scale, and rarely has such information been viewed as a resource for mapping the distribution of different ecological states. We examined the broad-scale effects of a shift from grassland to shrubland states on spatiotemporal patterns of remotely sensed ANPP proxies in the northern Chihuahuan Desert. We found that the normalized difference vegetation index (NDVI), when averaged across an eight-year period, did not vary significantly between these states, despite changes in ecosystem attributes likely to influence water availability to plants. In contrast, temporal relationships between precipitation and time-integrated NDVI (NDVI-I) modeled on a per-pixel basis were sensitive to spatial variation in shrub canopy cover, a key attribute differentiating ecological states in the region. The slope of the relationship between annual NDVI-I and 2-year cumulative precipitation was negatively related to, and accounted for 71% of variation in, shrub canopy cover estimated at validation sites using high spatial resolution satellite imagery. These results suggest that remote sensing studies of temporal precipitation-NDVI relationships may be useful for deriving shrub canopy cover estimates in the region, as well as for mapping other ecological state changes characterized by shifts in long-term ANPP, plant functional type dominance, or both.

Authors

Williamson, Jeb C.; Bestelmeyer, Brandon T.; Peters, Debra P. C.

Year Published

2012

Publication

Ecosystems

Locations
DOI

10.1007/s10021-011-9490-2

A multi-scale classification of vegetation dynamics in arid lands: What is the right scale for models, monitoring, and restoration?Bestelmeyer, BT2006

A multi-scale classification of vegetation dynamics in arid lands: What is the right scale for models, monitoring, and restoration?

Keywords

Chihuahuan Desert; geomorphology; soil quality; state-and-transition models; thresholds

Abstract

Measurements of vegetation and soil dynamics used to anticipate (or reverse) catastrophic transitions in arid and semi-arid 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 multi-temporal 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 semi-arid ecosystems and links spatial and temporal patterns in vegetation with ecological and geomorphic processes, monitoring, and restoration strategies. (c) 2005 Elsevier Ltd. All rights reserved.

Authors

Bestelmeyer, BT; Trujillo, DA; Tugel, AJ; Havstad, KM

Year Published

2006

Publication

Journal of Arid Environments

Locations
DOI

10.1016/j.jaridenv.2005.06.028

Spatial perspectives in state-and-transition models: a missing link to land management?Bestelmeyer, Brandon T.2011

Spatial perspectives in state-and-transition models: a missing link to land management?

Keywords

Chihuahuan Desert; contagion; Iceland; monitoring; patch dynamics; regime shift; southern Great Plains; spatial dependence; thresholds

Abstract

P>1. State-and-transition models (STMs) synthesize and communicate knowledge about the alternative states of an ecosystem and causes of state transitions. Data supported narrative descriptions within STMs are used to select or justify management actions. State transitions are characteristically heterogeneous in space and time, but spatial heterogeneity is seldom described in STMs, thereby limiting their utility. 2. We conducted a review that indicates how spatially explicit data can be used to improve STMs. We first identified three spatial scales at which spatial patterns and processes are manifest: patches, sites and landscapes. We then identified three classes of spatial processes that govern heterogeneity in state transitions at each scale and that can be considered in empirical studies, STM narratives and management interpretations. 3. First, spatial variations in land-use driver history (e.g. grazing use) can explain differences in the occurrence of state transitions within land areas that are otherwise uniform. Secondly, spatial dependence in response to drivers imposed by variations in soils, landforms and climate can explain how the likelihood of state transition varies along relatively static environmental gradients. Thirdly, state transition processes can be contagious, under control of vegetation-environment feedbacks, such that the spatiotemporal evolution of state transitions is predictable. 4. We suggest a strategy for considering each of the three spatial processes in the development of STM narratives. We illustrate how spatial data can be employed for describing early warning indicators of state transition, identifying areas that are most susceptible to state transitions, and designing and implementing monitoring schemes. 5. Synthesis and applications. State-and-transition models are increasingly important tools for guiding land-management activities. However, failure to adequately represent spatial processes in STMs can limit their ability to identify the initiation, risk and causes of state transitions and, therefore, the appropriate management responses. We suggest that multi-scaled studies targeted to different kinds of ecosystems can be used to uncover evidence of spatial processes. Such evidence should be included in STM narratives and can lead to novel interpretations of land change and improved management.

Authors

Bestelmeyer, Brandon T.; Goolsby, Darroc P.; Archer, Steven R.

Year Published

2011

Publication

Journal of Applied Ecology

Locations
DOI

10.1111/j.1365-2664.2011.01982.x

Does desertification diminish biodiversity? Enhancement of ant diversity by shrub invasion in south-western USABestelmeyer, BT2005

Does desertification diminish biodiversity? Enhancement of ant diversity by shrub invasion in south-western USA

Keywords

desert grassland; Dorymyrmex bicolor; Forelius; Formicidae; functional group; Prosopis glandulosa

Abstract

The conversion of desert grasslands to shrublands is a long-standing concern in the south-western 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 harboured four times the number of ant foragers found at the relatively 'pristine' Sevilleta site, with several ecologically dominant taxa driving this pattern, especially Dorymyrmex bicolor. Species richness and ecological dominance were 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.

Authors

Bestelmeyer, BT

Year Published

2005

Publication

Diversity And Distributions

Locations
DOI

10.1111/j.1366-9516.2005.00122.x

Does shrub invasion indirectly limit grass establishment via seedling herbivory? A test at grassland-shrubland ecotonesBestelmeyer, Brandon T.2007

Does shrub invasion indirectly limit grass establishment via seedling herbivory? A test at grassland-shrubland ecotones

Keywords

alternative state; Bouteloua eriopoda; Chihuahuan Desert; desertification; Dipodomys; foraging behavior; Lepus californicus; restoration; small mammal

Abstract

Question: Does shrub invasion at ecotones indirectly limit grass establishment by increasing mammalian seedling herbivory? Location: Chihuahuan Desert, New Mexico, USA. Methods: 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. Results: Seedlings were killed by mammals in greater numbers in shrubland than in grassland or middle ecotone positions at the site with large 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. Conclusions: Seedling herbivory is an important process and is related to vegetation composition, but the mechanisms underlying the relationship are not clear. We speculate that variation in small mammal foraging behavior may contribute to seedling herbivory patterns. Restoration strategies in the Chihuahuan Desert need to account for the abundance and/or behavior of native herbivores.

Authors

Bestelmeyer, Brandon T.; Kalil, N. I.; Peters, Debra P. C.

Year Published

2007

Publication

Journal of Vegetation Science

Locations
DOI

10.1111/j.1654-1103.2007.tb02548.x

Soil-geomorphic heterogeneity governs patchy vegetation dynamics at an arid ecotoneBestelmeyer, BT2006

Soil-geomorphic heterogeneity governs patchy vegetation dynamics at an arid ecotone

Keywords

autocorrelation; Chihuahuan Desert; patch dynamics; rangeland; self-organization; state-and-transition model; threshold

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 over a 60-year period, but shifts between bare and vegetated states, as well as persistently vegetated and bare states, occurred largely in small (< 40 m(2)) 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 carbonate and positively related to subsurface clay content. Thus, only a fraction of the landscape was Susceptible to vegetation change, and the sparsely vegetated area probably featured a higher frequency of susceptible soil patches. Patch dynamics and self-organizing processes can be constrained by subtle (and often unrecognized) soil heterogeneity.

Authors

Bestelmeyer, BT; Ward, JP; Havstad, KM

Year Published

2006

Publication

Ecology

Locations
DOI

10.1890/0012-9658(2006)87[963:SHGPVD]2.0.CO;2

This article contributed by:

Ecological Society of America

Local and regional-scale responses of ant diversity to a semiarid biome transitionBestelmeyer, BT2001

Local and regional-scale responses of ant diversity to a semiarid biome transition

Keywords

No keywords available

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 in 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 north 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.

Authors

Bestelmeyer, BT; Wiens, JA

Year Published

2001

Publication

Ecography

Locations
Using Unmanned Aerial Vehicles for Rangelands: Current Applications and Future PotentialsRango, Albert2006

Using Unmanned Aerial Vehicles for Rangelands: Current Applications and Future Potentials

Keywords

No keywords available

Abstract

High resolution aerial photographs have important rangeland applications, such as monitoring vegetation change, developing grazing strategies, determining rangeland health, and assessing remediation treatment effectiveness. Acquisition of high resolution images by Unmanned Aerial Vehicles (UAVs) has certain advantages over piloted aircraft missions, including lower cost, improved safety, flexibility in mission planning, and closer proximity to the target. Different levels of remote sensing data can be combined to provide more comprehensive information: 15–30 m resolution imaging from space-borne sensors for determining uniform landscape units; < 1 m satellite or aircraft data to assess the pattern of ecological states in an area of interest; 5 cm UAV images to measure gap and patch sizes as well as percent bare soil and vegetation ground cover; and < 1 cm ground-based boom photography for ground truth or reference data. Two parallel tracks of investigation are necessary: one that emphasizes the utilization of the most technically advanced sensors for research, and a second that emphasizes the minimization of costs and the maximization of simplicity for monitoring purposes. We envision that in the future, resource management agencies, rangeland consultants, and private land managers should be able to use small, lightweight UAVs to satisfy their needs for acquiring improved data at a reasonable cost, and for making appropriate management decisions.

Authors

Bestelmeyer, Brandon, Herrick, Jeffrey E., Laliberte, Andrea, Rango, Albert, Steele, Caiti, Schmugge, Thomas, Roanhorse, Abigail and Jenkins, Vince

Year Published

2006

Publication

Environmental Practice

Locations
DOI

10.1017/S1466046606060224

State-and-Transition Models for Heterogeneous Landscapes: A Strategy for Development and ApplicationBestelmeyer, Brandon T.2009

State-and-Transition Models for Heterogeneous Landscapes: A Strategy for Development and Application

Keywords

climate, dynamic soil properties, ecological sites, inventory, monitoring, quantile regression, soils, state-and-transition models, threshold

Abstract

Interpretation of assessment and monitoring data requires information about how reference conditions and ecological resilience vary in space and time. Reference conditions used as benchmarks are often 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 specify indicators of ecological resilience and thresholds. Although general concepts surrounding STMs and ecological sites have received increasing attention, strategies to apply and quantify these concepts 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 that reveal processes interacting across spatial scales. We recommend a sequence of eight steps for the co-development of ecological sites and STMs, including 1) creation of initial concepts based on literature and workshops; 2) extensive, low-intensity traverses to refine 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 single 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. We offer a simple example of how data assembled via our sequence are 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.

Authors

Herrick, Jeffrey E., Bestelmeyer, Brandon T., Havstad, Kris M., Tugel, Arlene J., Peacock, George L., Robinett, Daniel G., Shaver, Pat L., Brown, Joel R. and Sanchez, Homer

Year Published

2009

Publication

Rangeland Ecology & Management

Locations
DOI

10.2111/08-146

Recent Articles

Constraints and Time Lags for Recovery of a Keystone Species (dipodomys Spectabilis) After Landscape Restoration

by Cosentino, Bradley J., Schooley, Robert L., Bestelmeyer, Brandon T., Kelly, Jeffrey F. and Coffman, John M.

Habitat restoration is typically focused on reestablishing suitable conditions at a local scale, but landscape constraints may be important for keystone species with limited dispersal. We tested for time lags and examined the relative importance of local and landscape constraints on the response of the banner-tailed kangaroo rat (Dipodomys spectabilis) to restoration of Chihuahuan Desert grassl...

published 2014 in Landscape Ecology

Effects of Grassland Restoration Efforts on Mound-Building Ants in the Chihuahuan Desert

by McAllister, Monica M., Schooley, Robert L., Bestelmeyer, Brandon T., Coffman, John M. and Cosentino, Bradley J.

Shrub encroachment is a serious problem in arid environments worldwide because of potential reductions in ecosystem services and negative effects on biodiversity. In southwestern USA, Chihuahuan Desert grasslands have experienced long-term encroachment by shrubs including creosotebush (Larrea tridentata). Land managers have attempted an ambitious intervention to control shrubs by spraying herbi...

published 2014 in Journal of Arid Environments


Restoration Practices Have Positive Effects on Breeding Bird Species of Concern in the Chihuahuan Desert

by Coffman, John M., Bestelmeyer, Brandon T., Kelly, Jeffrey F., Wright, Timothy F. and Schooley, Robert L.

Woody plant encroachment into grasslands is a global concern. Efforts to restore grasslands often assume that removal of woody plants benefits biodiversity but assumptions are rarely tested. In the Chihuahuan Desert of the Southwestern United States, we tested whether abundances of grassland specialist bird species would be greater in plant communities resulting from treatment with herbicides t...

published 2014 in Restoration Ecology

A Test of Critical Thresholds and Their Indicators in a Desertification-Prone Ecosystem: More Resilience than We Thought

by Bestelmeyer, Brandon T., Duniway, Michael C., James, Darren K., Burkett, Laura M. and Havstad, Kris M.

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 metric...

published 2013 in Ecology Letters