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A collection of articles lead or co-authored by Debra Peters, Rangeland Ecologist, Range Management Research Unit, USDA-ARS Jornada Experimental Range.

Description

My research focuses on understanding and predicting the dynamics of arid and semiarid systems across a range of spatial and temporal scales. Much of my research involves interactions within and among various species of grasses and shrubs with a focus on extrapolating patterns and processes across scales, from individual plants to patches, landscapes, and regions. Current projects include (1) the examination of spatial variation in shrub invasion and grass persistence, (2) the study of ecotones and biotic transitions at multiple scales, (3) predicting nonlinear spatial dynamics of cascading systems, (4) using cross-site studies to generalize processes and patterns, and (5) integrating process-based experiments with simulation models (ECOTONE), geographic information systems (GIS), and remote sensed images. Research is conducted at a number of sites in Colorado, New Mexico, and Texas with most studies occurring at the Jornada Basin Long Term Ecological Research (LTER) site in southern NM and the Sevilleta National Wildlife Refuge LTER site in central NM. Collaborative research is being conducted at three sites in Hungary.

latest article added on October 2014

ArticleFirst AuthorPublished
Soil-vegetation-climate interactions in arid landscapes: Effects of the North American monsoon on grass recruitment.Peters, Debra P.C.2010

Soil-vegetation-climate interactions in arid landscapes: Effects of the North American monsoon on grass recruitment.

Keywords

Bouteloua eriopoda ; Chihuahuan Desert ; Perennial grass ; Plant-soil feedbacks ; Simulation model ; State change

Abstract

We used a daily time step, multi-layer simulation model of soil water dynamics to integrate effects of soils, vegetation, and climate on the recruitment of Bouteloua eriopoda (black grama), the historically dominant grass in the Chihuahuan Desert. We simulated landscapes at the Jornada ARS-LTER site with heterogeneous soil properties to compare: (1) a grass-dominated landscape in 1858 with the current shrub-dominated landscape (i.e., a change in vegetation structure), and (2) the current shrub-dominated landscape with future landscapes over a range of climate scenarios associated with the North American monsoon (i.e., a change in climate). A historic shift from high productivity grasslands to low productivity shrublands decreased simulated recruitment for most of the site; the amount of reduction depended on location-specific soil properties and changes in production. In some cases, soil properties interacted with vegetation structure: soils high in clay content maintained high recruitment even with a decrease in production. Wetter summers would increase recruitment in all vegetation types. Drier summers below 25% of current rainfall would decrease recruitment to negligible values (<0.03) throughout the landscape. We used our results to identify the conditions where recruitment of B. eriopoda is possible with and without significant modifications to soil and vegetation.

Authors

Debra P.C. Peters, Jeffrey E. Herrick, H. Curtis Monger, Haitao Huang

Year Published

2010

Publication

Journal of Arid Environments

Locations
DOI

10.1016/j.jaridenv.2009.09.015

Long-term data collection at USDA experimental sites for studies of ecohydrologyMoran, M. Susan2008

Long-term data collection at USDA experimental sites for studies of ecohydrology

Keywords

ecohydrology; watersheds; forests; ranges; USDA; long-term

Abstract

The science of ecohydrology is characterized by feedbacks, gradual trends and extreme events that are best revealed with long-term experimental studies of hydrological processes and biological communities. fit this review, we identified 81 US Department of Agriculture (USDA) experimental watersheds. forests and ranges with data records of more than 20 years measuring important ecosystem dynamics such as variations in vegetation, precipitation, climate, runoff, water quality and soil moisture. Through a series of examples, we showed how USDA long-term data have been used to understand key ecohydrological issues, including (1) time lag between cause and effects, (2) critical thresholds and cyclic trends, (3) context of rare and extreme events and (4) mechanistic feedbacks for simulation modelling. New analyses of network-wide, long-term data from USDA experimental sites were used to illustrate the potential for multi-year, multi-site ecohydrological research. Three areas of investigation were identified to best exploit the unique spatial distribution and long-term data of USDA experimental sites: convergence, cumulative synthesis and autocorrelation. This review underscored the need for continuous, interdisciplinary data records spanning more than 20 years across a wide range of ecosystems within and Outside the conterminous USA to address major crosscutting problems facing ecohydrology. Conversely, the heightened interest in ecohydrology has impacted USDA experimental sites by encouraging new long-term data collection efforts and adapting existing long-term data collection networks to address new science issues. Copyright (C) 2008 John Wiley & Sons, Ltd.

Authors

Moran, M. Susan; Peters, Debra P. C.; McClaran, Mitchel P.; Nichols, Mary H.; Adams, Mary B.

Year Published

2008

Publication

Ecohydrology

Locations
DOI

10.1002/eco.24

High-resolution images reveal rate and pattern of shrub encroachment over six decades in New Mexico, U.S.A.Goslee, SC2003

High-resolution images reveal rate and pattern of shrub encroachment over six decades in New Mexico, U.S.A.

Keywords

Chihuahuan desert grassland; Rrosopis glandulosa; remote sensing; shrub encroachment

Abstract

Encroachment of the shrub Prosopis glandulosa Torn (honey mesquite) into semi-arid grasslands is a serious concern in the south-western United States, yet little is known about the long-term dynamics of the invasion process. We used ten high-resolution aerial and satellite images taken from 1936 to 1996 to track the population dynamics and spatial pattern of all P glandulosa greater than 2 in in diameter on a 75 ha area in southern New Mexico. Shrub cover and patch numbers increased froth 1936 to the 1970s, then stabilized at 43% cover and 83 patches ha(-1). Individual patches were extremely persistent: 95% of the area occupied by shrub patches in 1936 was still occupied in 1996. Recruitment into the 2 in size class was more variable: 0.6-5.2% year(-1) (mean 0-8% year(-1)). Patch-shape complexity increased from 1936 to 1983 as adjacent shrubs merged, and then declined as those clusters filled in and became rounder. Spatial pattern of shrubs showed a distinct trend over time: strongly clustered in 1936 at lag distances up to 250 m, then random arrangement at all scales, and by 1983 pattern was regular at lag distances greater than 100 m. There was no clear relationship with precipitation. The use of remote sensing imagery allowed us to examine one site over time, and revealed patterns in population dynamics and spatial pattern that would not have been visible otherwise. Comparison of field estimates collected in 2001 with 1996 image data suggest that the canopy cover estimates were accurate, but shrub densities were seriously underestimated in the satellite photographs, which do not show shrubs smaller than 2 m diameter. As long as limitations of the imagery are understood, these methods can be applied over a larger and more heterogeneous area to examine environmental correlates of invasion success. (C) 2003 Elsevier Science Ltd.

Authors

Goslee, SC; Havstad, KM; Peters, DPC; Rango, A; Schlesinger, WH

Year Published

2003

Publication

Journal of Arid Environments

Locations
DOI

10.1006/jare.2002.1103

Population and clonal level responses of a perennial grass following fire in the northern Chihuahuan DesertDrewa, Paul B.2006

Population and clonal level responses of a perennial grass following fire in the northern Chihuahuan Desert

Keywords

Bouteloua eriopoda; fire intensity; grazing; precipitation; resprouting

Abstract

Relationships involving fire and perennial grasses are controversial in Chihuahuan Desert grasslands of southern New Mexico, USA. Research suggests that fire delays the resprouting of perennial grasses well after two growing seasons. However, such results are confounded by livestock grazing, soil erosion, and drought. Additionally, post-fire grass responses may depend on initial clone size. We evaluated the effects of fire, grazing, and clone size on Bouteloua eriopoda (black grama) in southern New Mexico grasslands. Four 2-ha plots were established in each of four sites. Fire and grazing were applied or not applied in 1999 such that four treatment combinations were assigned randomly to plots within each site. Within each plot, small (0-10 cm(2) basal area), medium (10-30 cm(2)), and large (> 30 cm(2)) clones were initially mapped in five 0.91-m(2) quadrats where grass attributes and litter cover were evaluated before and at the end of two growing seasons following fire. Maximum fire temperature was also measured. At a population level, canopy and litter cover were each approximately 50% less in burned than unburned areas. However, compared to initial levels, canopy height had increased by 10% at the end of the study, regardless of fire. At a clonal level, basal cover reductions were attributed mostly to large clones that survived fire. Smaller clone densities had decreased by as much as 19% in burned compared to unburned areas, and fire reduced the basal cover of medium clones. Basal and canopy cover, recruitment, and clone basal area decreased with increased fire temperatures. Almost all responses were independent of grazing, and interactive effects of grazing and fire were not detected. Fire did not kill all perennial grass clones, regardless of size. However, rapid responses were likely influenced by above-average precipitation after fire. Future studies in desert grasslands should examine how perennial grass dynamics are affected by fire, precipitation patterns, and interactions with grazing.

Authors

Drewa, Paul B.; Peters, Debra P. C.; Havstad, Kris M.

Year Published

2006

Publication

Oecologia

Locations
DOI

10.1007/s00442-006-0502-4

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

Multi-scale factors and long-term responses of Chihuahuan Desert grasses to droughtYao, Jin2006

Multi-scale factors and long-term responses of Chihuahuan Desert grasses to drought

Keywords

arid grasslands; desertification; drought; grazing; perennial grasses; transport processes

Abstract

Factors with variation at broad (e.g., climate) and fine scales (e.g., soil texture) that influence local processes at the plant scale (e.g., competition) have often been used to infer controls on spatial patterns and temporal trends in vegetation. However, these factors can be insufficient to explain spatial and temporal variation in grass cover for and and semiarid grasslands during an extreme drought that promotes woody plant encroachment. Transport of materials among patches may also be important to this variation. We used long-term cover data (19152001) combined with recently collected field data and spatial databases from a site in the northern Chihuahuan Desert to assess temporal trends in cover and the relative importance of factors at three scales (plant. patch, landscape unit) in explaining spatial variation in grass cover. We examined cover of five important grass species from two topographic positions before, during, and after the extreme drought of the 1950s. Our results show that dynamics before, during, and after the drought varied by species rather than by topographic position. Different factors were related to cover of each species in each time period. Factors at the landscape unit scale (rainfall, stocking rate) were related to grass cover in the pre- and post-drought periods whereas only the plant-scale factor of soil texture was significantly related to cover of two upland species during the drought. Patch-scale factors associated with the redistribution of water (microtopography) were important for different species in the pre- and post-drought period. Another patch-scale factor, distance from historic shrub populations, was important to the persistence of the dominant grass in uplands (Bouteloua eriopoda) through time. Our results suggest the importance of local processes during the drought, and transport processes before and after the drought with different relationships for different species. Disentangling the relative importance of factors at different spatial scales to spatial patterns and long-term trends in grass cover can provide new insights into the key processes driving these historic patterns, and can be used to improve forecasts of vegetation change in and and semiarid areas.

Authors

Yao, Jin; Peters, Debra P. C.; Havstad, Kris M.; Gibbens, Robert P.; Herrick, Jeffrey E.

Year Published

2006

Publication

Landscape Ecology

Locations
DOI

10.1007/s10980-006-0025-8

Nonlinear dynamics in arid and semi-arid systems: Interactions among drivers and processes across scalesPeters, DPC2006

Nonlinear dynamics in arid and semi-arid systems: Interactions among drivers and processes across scales

Keywords

conceptual framework; cross scale interactions; historical legacies; landscape context; resource redistribution; threshold behavior; transport processes

Abstract

We discuss a new conceptual framework for arid and semi-arid systems that accounts for nonlinear dynamics and cross scale interactions in explaining landscape patterns and dynamics. Our framework includes a spatial and temporal hierarchy, and five key interacting components that connect scales of the hierarchy and generate threshold behaviors: (1) historical legacies that include climate, disturbance, and management regimes, (2) dynamic template of patterns in ecological variables and spatial context, (3) vertical and horizontal transport processes (fluvial, aeolian, animal), (4) rate, direction, and amount of resource redistribution between high and low resource areas, and (5) feedbacks among plants, animals, and soils. We illustrate how this framework can be used to understand, forecast, and manage ecological systems that exhibit nonlinear dynamics across a range of spatial and temporal scales. This paper provides the foundation for a series of papers from the Jornada Experimental Range ARS-LTER research site in southern New Mexico, USA that support this new conceptual framework. Published by Elsevier Ltd.

Authors

Peters, DPC; Havstad, KM

Year Published

2006

Publication

Journal of Arid Environments

Locations
DOI

10.1016/j.jaridenv.2005.05.010

Plant species dominance at a grassland-shrubland ecotone: an individual-based gap dynamics model of herbaceous and woody speciesPeters, DPC2002

Plant species dominance at a grassland-shrubland ecotone: an individual-based gap dynamics model of herbaceous and woody species

Keywords

Bouteloua species; Chihuahuan desert; climate change; creosotebush; ECOTONE; shortgrass steppe

Abstract

Transition zones or ecotones between biomes are predicted to be particularly sensitive areas to directional changes in climate. However, for many ecotones, there is little understanding of the key processes that allow dominant species from adjacent biomes to coexist at transition zones and how differences in these processes affect species responses to changes in environmental conditions. The objective of this study was to examine the relationship between plant life history traits and patterns in dominance and composition at a grassland-shrubland and transition zone in order to predict shifts in dominance with directional changes in climate. It was hypothesized that differences in life history traits allow species from adjacent biomes to coexist at this transition zone, and that these dominance patterns are dynamic through time as a result of species-specific responses to changes in climate. A mixed lifeform individual plant-based gap dynamics model (ECOTONE) was developed to examine consequences of differences in recruitment, resource acquisition, and mortality to patterns in species dominance and composition under a variety of soils and climatic conditions. This model is unique because it represents interactions among multiple potential dominant species that include congeneric species of one lifeform as well as herbaceous and woody lifeforms across multiple spatial scales. Similar to other gap models, ECOTONE simulates the recruitment, growth, and mortality of individual plants on a small plot through time at an annual timestep. ECOTONE differs from other gap models in the degree of detail involved in determining successful recruitment by each species and in the simulation of belowground resources. Individual plant root distributions and resource availability by depth are dynamic. Soil water content is simulated on a daily timestep and nitrogen is simulated monthly. Multiple spatial scales can be simulated using a grid of plots connected by seed dispersal. ECOTONE was parameterized for two soil types at the Sevilleta National Wildlife Refuge (SEV), a site located within the transition zone between two major biomes in North America. Shortgrass steppe communities are dominated by the perennial grass Bouteloua gracilis (blue grama) and Chihuahuan desert communities are dominated by the perennial grass Bouteloua eriopoda (black grama) or the shrub Larrea tridentata (creosotebush). Experiments were conducted to provide key parameters related to recruitment and growth that were supplemented with information from the literature for remaining parameters. Model output was verified using field estimates of cover and biomass for the three dominant species as well as other groups of species. Simulation analyses were conducted under current climate and for a directional change in climate. Nitrogen was assumed constant for all runs to allow a focus on water availability constraints as affected by climate. Under Current climatic conditions, Simulated biomass on sandy loam soils was dominated by B. eviopoda with smaller biomass of B. gracilis and other species groups. By contrast, simulated biomass on a loamy sand soil was codominated by B. eriopoda and L. tridentata with very small biomass attributed to other species groups. Under a GFDL climate change scenario of increased year-round temperatures and increased Summer precipitation. vegetation patterns shifted to a clear dominance of biomass by B. eriopoda on both soil types. These results show that temporal partitioning of soil water is important to codominance by the two Bouteloua species, and that spatial and temporal partitioning of soil water is important for grass-shrub interactions. The results also suggest that global climate change may provide a mechanism for the recovery of B. eriopoda following shrub invasion in the Southwestern U.S. Thus, an individual-based modeling approach is capable of representing complex interactions among herbaceous and woody species as well as between congeneric species with different life history traits at a biome transition zone. This modeling approach is useful in improving our understanding of key processes driving these vegetation dynamics as well in predicting shifts in dominance as environmental conditions change in the future. (C) 2002 Published by Elsevier Science B.V.

Authors

Peters, DPC

Year Published

2002

Publication

Ecological Modelling

Locations
DOI

10.1016/S0304-3800(01)00460-4

Shrub encroachment in North American grasslands: shifts in growth form dominance rapidly alters control of ecosystem carbon inputsKnapp, Alan K.2008

Shrub encroachment in North American grasslands: shifts in growth form dominance rapidly alters control of ecosystem carbon inputs

Keywords

aboveground net primary production; carbon; climate change; grasslands; growth form; LAI; MAP; shrublands

Abstract

Shrub encroachment into grass-dominated biomes is occurring globally due to a variety of anthropogenic activities, but the consequences for carbon (C) inputs, storage and cycling remain unclear. We studied eight North American graminoid-dominated ecosystems invaded by shrubs, from arctic tundra to Atlantic coastal dunes, to quantify patterns and controls of C inputs via aboveground net primary production (ANPP). Across a fourfold range in mean annual precipitation (MAP), a key regulator of ecosystem C input at the continental scale, shrub invasion decreased ANPP in xeric sites, but dramatically increased ANPP (> 1000 g m(-2)) at high MAP, where shrub patches maintained extraordinarily high leaf area. Concurrently, the relationship between MAP and ANPP shifted from being nonlinear in grasslands to linear in shrublands. Thus, relatively abrupt (< 50 years) shifts in growth form dominance, without changes in resource quantity, can fundamentally alter continental-scale pattern of C inputs and their control by MAP in ways that exceed the direct effects of climate change alone.

Authors

Knapp, Alan K.; Briggs, John M.; Collins, Scott L.; Archer, Steven R.; Bret-Harte, M. Syndonia; Ewers, Brent E.; Peters, Debra P.; Young, Donald R.; Shaver, Gaius R.; Pendall, Elise; Cleary, Meagan B.

Year Published

2008

Publication

Global Change Biology

Locations
DOI

10.1111/j.1365-2486.2007.01512.x

Directional climate change and potential reversal of desertification in arid and semiarid ecosystemsPeters, Debra P. C.2012

Directional climate change and potential reversal of desertification in arid and semiarid ecosystems

Keywords

extreme events; grasslands; regime shift; shrublands; spatial context; wet-dry climatic periods

Abstract

Our objective was to determine if long-term increases in precipitation can maintain grasslands susceptible to desertification, and initiate a reversal of historic regime shifts on desertified shrublands. Perennial grass production and species richness in a multi-year wet period were hypothesized to be greater than expected based on precipitation in a sequence of dry years. These responses were expected to differ for grasslands and shrublands with different dominant species and topo-edaphic properties. Long-term trends in desertification were documented using vegetation maps beginning in 1858, 1915, 1928, and 1998). These trends were compared with herbaceous and woody species responses to a sequence of dry (19942003) and wet years (20042008) for two grassland (uplands, playas) and three desertified shrubland types (honey mesquite, creosotebush, tarbush) in the Chihuahuan Desert. Analyses showed that both types of grasslands decreased in spatial extent since 1858 whereas areas dominated by mesquite or creosotebush increased. Production of upland grasslands in the wet period was greater than expected based on responses during the dry period whereas the relationships between species richness and precipitation was the same for both periods. Precipitation was not important to responses in playa grasslands in either period. For all ecosystem types, the production response in wet years primarily was an increase in herbaceous plants, and the most pronounced responses occurred on sandy sites (upland grasslands, mesquite shrubland). Results suggest that multiple wet years are needed to initiate a sequence of grass establishment and survival processes that can maintain upland grasslands without management inputs and lead to a state change reversal in desertified shrublands. Restoration strategies need to take advantage of opportunities provided by future climates while recognizing the importance of ecosystem type.

Authors

Peters, Debra P. C.; Yao, Jin; Sala, Osvaldo E.; Anderson, John P.

Year Published

2012

Publication

Global Change Biology

Locations
DOI

10.1111/j.1365-2486.2011.02498.x

Recent Articles

Functional Response of U.s. Grasslands to the Early 21st-Century Drought

by Moran, M. Susan, Ponce-Campos, Guillermo E., Huete, Alfredo, McClaran, Mitchel P., Zhang, Yongguang, Hamerlynck, Erik P., Augustine, David J., Gunter, Stacey A., Kitchen, Stanley G., Peters, Debra P. C., Starks, Patrick J. and Hernandez, Mariano

Grasslands across the United States play a key role in regional livelihood and national food security. Yet, it is still unclear how this important resource will respond to the prolonged warm droughts and more intense rainfall events predicted with climate change. The early 21st-century drought in the southwestern United States resulted in hydroclimatic conditions that are similar to those e...

published 2014 in Ecology

Mechanisms of Grass Response in Grasslands and Shrublands During Dry or Wet Periods

by Peters, Debra P. C., YAO, JIN, Browning, Dawn and Rango, Albert

Multi-year climatic periods are expected to increase with global change, yet long-term data are often insufficient to document factors leading to ecological responses. We used a suite of long-term datasets (1993– 2010) to examine the processes underlying different relationships between aboveground net primary production (ANPP) and precipitation in wet and dry rainfall periods in shrublands and...

published 2014 in Oecologia


Water Controls on Nitrogen Transformations and Stocks in an Arid Ecosystem

by Reichmann, Lara G., Sala, Osvaldo E. and Peters, Debra P. C.

Following water, nitrogen (N) is the most frequent limiting factor to aboveground net primary production in arid ecosystems. Increased water availability can stimulate both plant nitrogen uptake and microbial nitrogen mineralization, but may also stimulate losses from the ecosystem. Here, we assess the effect of water availability on nitrogen stocks and transformations in an arid ecosystem. We ...

published 2013 in Ecosphere

Regional Signatures of Plant Response to Drought and Elevated Temperature Across a Desert Ecosystem

by Munson, Seth M., Muldavin, Esteban H., Belnap, Jayne, Peters, Debra P. C., Anderson, John P., Reiser, M. Hildegard, Gallo, Kirsten, Melgoza-Castillo, Alicia, Herrick, Jeffrey E. and Christiansen, Tim A.

The performance of many desert plant species in North America may decline with the warmer and drier conditions predicted by climate change models, thereby accelerating land degradation and reducing ecosystem productivity. We paired repeat measurements of plant canopy cover with climate at multiple sites across the Chihuahuan Desert over the last century to determine which plant species and ...

published 2013 in Ecology