About

Osvaldo Sala is the Julie A. Wrigley, Regents, and Foundation Professor at Arizona State University, contributing to the School of Life Sciences, School of Sustainability, and School of Transborder Studies. He is the Founding Director of the Global Drylands Center and serves as Special Advisor to the Provost. Prior to joining ASU in 2010, he was at Brown University where he was the founding Director of the Environmental Change Initiative and the Sloan Lindemann Professor of Biology. His work is highly cited in ecology, sustainability, and biology, with 260 publications, over 72,000 citations, and an H-index of 114. His influential 2000 Science paper "Global Biodiversity Scenarios for the year 2100" has been cited more than 12,000 times. Sala's research is interdisciplinary, collaborating with geologists, social scientists, mathematicians, and humanists, and employs a variety of methods from experimentation to simulation modeling. He is well known for his field experiments in drylands conducted worldwide, including Patagonia, the Kalahari Desert, the Loess Plateau in China, and various U.S. ecosystems such as the Shortgrass steppe and Chihuahuan Desert. He maintains active scientific collaborations globally and leads a research lab at ASU supported by grants from the National Science Foundation, USDA, and Department of Energy. Sala's research interests focus on the functioning of arid ecosystems, ecosystem services, biodiversity, and the impacts of climate change, particularly changes in water availability. He has contributed to understanding biogeochemical and structural mechanisms underlying ecosystem responses to water availability changes and has explored how biodiversity changes affect ecosystem functioning. At a global scale, he has developed biodiversity change scenarios for the next 50 to 100 years, using scenarios to simplify and communicate complex social-ecological system relationships. His research employs manipulative field experiments, data synthesis, and simulation modeling across diverse ecosystems including the Patagonian steppe, California grasslands, Colorado steppes, Southern African deserts, and the Chihuahuan Desert. Throughout his career, Sala has demonstrated strong leadership and commitment to environmental problem solving. Internationally, he has served as President of the Scientific Committee on Problems of the Environment (SCOPE), contributed to the Millennium Ecosystem Assessment and the Intergovernmental Panel on Climate Change, and participated in the International Geosphere-Biosphere Program. He was President of the Ecological Society of America, the first Latin American and Hispanic scholar to hold this position, and currently serves on the National Academies Committee overseeing the US Global Change Research Program. In Latin America, he led the Ecological Society of Argentina and the Latin American Association of Botany. His contributions have been recognized by election to the American Academy of Arts and Sciences, the Argentinean National Academy of Sciences, and the Argentinean National Academy of Physical and Natural Sciences, and he is a Fellow of the Guggenheim Foundation, AAAS, ESA, and the American Geophysical Union.

Research topics

• Ecology
• Biology
• Environmental science
• Geography
• Political Science
• Environmental resource management
• Geology
• Environmental planning
• Agroforestry
• Soil science
• Mathematics
• Atmospheric sciences
• Agronomy

Selected publications

• Jornada Basin LTER (2018-2019) data and code for the Ecology publication “Shrub and grass soil-resource partitioning as modulated by precipitation amount and size of individual"

  Open MIND · 2026-01-01

  datasetOpen accessSenior author

  This data package contains data and code associated with a plant root tracer experiment (Study 469) conducted at the Jornada Basin LTER site in southern New Mexico, U.S.A, associated with the Ecology journal article “Shrub and grass soil-resource partitioning as modulated by precipitation amount and size of individual". The study was designed to investigate the root absorption profiles of dominant Prosopis glandulosa shrub and Bouteloua eriopoda grass. In September 2018 and September 2019, either LiCl tracer (treatment) or water (control) was injected to beneath 64 Prosopis glandulosa shrubs with co-located Bouteloua eripoda grasses. Injection depths ranged from 10 to 120 cm beneath the soil surface. Aboveground photosynthetic plant tissue was collected from target shrubs and grasses 21 days following each injection. Milled plant tissue samples were analyzed for Li content (concentration in ppm) using ICP-OES techniques in order to quantify plant root uptake activity. R scripts included in this package duplicate the data preparation and statistical analyses performed to model the soil-resource uptake of shrubs and grasses under divergent soil moisture conditions. This study and the dataset are completed.

  PublisherOA PDFDOI

• Acclimation of the Nitrogen Cycle to Changes in Precipitation

  Ecosystems · 2026-01-29

  articleOpen accessSenior author

  Abstract Climate change drivers elicit ecosystem responses that vary through time. We propose that the mismatch between equilibrium and transient ecosystem response defines ecological acclimation. As precipitation is expected to shift under climate change, we asked how both increases and decreases in water availability elicit ecological acclimation of the N cycle and how long does this acclimation take. Using foliar δ 15 N as a proxy for N cycling processes, we found that the slope of foliar δ 15 N decreases with mean annual precipitation across continents. However, within a desert grassland, slopes of interannual foliar and soil δ 15 N increased with precipitation amount. Using precipitation manipulation field experiments, we then assessed trends in foliar and soil δ 15 N as duration of the precipitation manipulation increased, from 5 to 14 years. When parsed temporally, the δ 15 N-precipitation slopes showed initially increasing trends that decreased after 14 years of precipitation manipulation. The difference in directionality of spatial δ 15 N-precipitation slope compared to within-site, experimental δ 15 N-precipitation slopes revealed potential acclimation of the N cycle. Furthermore, we estimated rates of ecological acclimation—defined as convergence time for within-site δ 15 N-precipitation slopes to match the global model—to range from 11 to 18 years. We conclude N cycling is changing with precipitation amount and duration of the altered precipitation regime. We hypothesize that fast and slow ecological mechanisms—such as microbial processes and shifts in plant species dominance, respectively—explain ecological acclimation of N cycling responses to climate change. As a result, spatial models must be interpreted with caution when forecasting future responses to climate change.

  PublisherOA PDFDOI

• Shrub and grass soil‐resource partitioning as modulated by precipitation amount and size of individual

  Ecology · 2026-05-01

  articleSenior author

  Plant-root uptake underpins the flow of water and nutrients through terrestrial ecosystems. Water and nutrients are heterogeneously distributed in soil and vary among wet and dry years. Shrubs and grasses have different root distributions extending to different soil depths. We asked three questions: (1) What are the depth profiles of root absorption of the dominant shrub and grass species of the northern Chihuahuan drylands? (2) How do their absorption profiles change from wet to dry years? (3) How does the absorption profile of the dominant shrub Prosopis glandulosa change with shrub size? Using a tracer, we measured soil-resource uptake by neighboring shrubs and grasses in the top 120 cm of the soil. Grass absorption profiles were shallower and more flexible than those of shrubs, which showed little change between dry and wet years. Shrub-rooting depth increased swiftly with size; all shrubs above the 20th percentile of aboveground volume displayed deeper absorption than grasses. We showed that shrub-grass competition for soil resources is minimal and limited to early shrub establishment stages. Our results assist in understanding woody-plant encroachment and future plant community structure and ecosystem functioning under a hotter, drier, and more variable climate.

  PublisherDOI

• Global destocking of extensive livestock: An overlooked trend with Earth system consequences

  Proceedings of the National Academy of Sciences · 2026-01-12 · 2 citations

  articleOpen accessSenior author

  Managed grazing is the most extensive land use on Earth. The prevailing narrative is that global rangelands, from grasslands to deserts, are being degraded by overgrazing due to overstocking. This perception arises from scientific literature, which contains an order of magnitude more studies on overstocking than on reductions in stocking rates. In contrast, over the past 25 y, regions representing almost half (42%) of global livestock have experienced reductions in stocking rates rather than the expected increases. We evaluated socioeconomic, technological, and climatic direct drivers, as well as indirect drivers, of global stocking patterns. Trade and climate had no detectable effects, whereas technological shifts and meat consumption had an impact on stocking rates. Direct drivers were largely controlled by human population and gross domestic product. Wealthier regions, with slower population growth, greater feed supplementation, and reliance on nongrazing livestock, reduced stocking rates. Less affluent regions, facing rapid population growth and rising meat demand but limited technological and feed resources, increased stocking rates. The overlooked reductions in stocking rates may have major ecological consequences at regional and global scales. Destocking can impact biodiversity, fire regimes, potentially increase carbon sequestration, and modify land-atmosphere fluxes. These effects are not simply the reverse of overstocking, as some consequences are irreversible, including state transitions and local extinctions. The skewed pattern of publications toward overstocking and overgrazing led to a perception of widespread degradation and had consequences on research direction and policy.

  PublisherDOI

• Effects of precipitation, competition, and predation on the germination and establishment of a drylands-invasive grass from 2016-2018

  Open MIND · 2026-01-01

  datasetOpen access

  This dataset was used to assess the germination and establishment of Eragrostis lehmanniana (Lehmann Lovegrass) under varied growing season precipitation, competition with native grasses, predator identity, and the interaction of these factors. Data were collected from 2016 to 2018 at a project area within the Jornada Experimental Range, a Long-Term Ecological Research site approximately 30 km north of Las Cruces, NM, USA (32 33037.4400 N, 106 46026.6500 W). The experimental site was dominated with Bouteloua eriopoda with scattered Neltuma glandulosa shrubs. Thirty plots were established based on similarity of native grass cover and size of a central N. glandulosa shrub. This experiment utilized a split-plot design: precipitation was altered at the plot-level, competition was altered within each plot at the half-plot level, and predation treatments were established within each half-plot at the subplot-level. Precipitation treatments altered growing season precipitation (June to the end of September) using an automatic rainfall manipulation system (ARMS; Gherardi and Sala 2013). One of three precipitation treatments were randomly assigned to plots: -80% of ambient, ambient, +80% of ambient. Within each plot, competition from native grasses was altered at two levels: "control" plot-halves were unaltered, and "reduced" plot-halves were repeatedly clipped to reduce the competitive ability of native grasses through defoliation. Predator identity was manipulated by installing different exclosures within subplots to create four levels of predator-identify treatments: all predators, ant access, lagomorph access, and no predators. There were a total of 10 replicates of each precipitation, competition, and predation treatment combination (3 precipitation treatments * 2 competition treatments * 4 predation treatments * 10 replicates = 240 total subplots).

  PublisherOA PDFDOI

• Hydrologic Dynamics of Ephemerally Flooded Playas in a Dryland Environment

  Water Resources Research · 2026-01-01

  articleOpen access

  Abstract Ephemerally flooded playas are common in the southwestern United States and globally in drylands. Often formed in closed basins, playas are depressions which inundate infrequently from local precipitation and streamflow produced near the playa or from upland areas. Few studies have quantified the hydrologic connectivity between upland catchments and playas using observations. Here, we used rain gauge‐corrected precipitation from weather radar and water level measurements in 18 playas of the Chihuahuan Desert to identify precipitation thresholds leading to playa inundation over a 6.4‐year period. Geospatial data sets on topography, soil properties, and vegetation cover were employed to determine the controls on inundation. Only 9.4% of all precipitation events above 1 mm led to inundation, with 69.8% of all inundations occurring during the North American monsoon (NAM, July‐September). Mean and standard deviations (Std) of runoff ratios at all playas were 2.74 ± 4.08% and 3.29 ± 5.19% for annual and NAM periods. At the annual scale, playa inundation occurred when mean precipitation thresholds of 18.3 ± 7.5 mm (event total) and 12.0 ± 4.5 mm/hr (60‐min intensity) were exceeded. Across all playas, inundation occurrence and volume were related most strongly to precipitation metrics and catchment area, with secondary controls of soil and terrain properties. The explanatory power of the derived regressions describing the inundation response across the playas were significantly improved when considering their geological origin. As a result, the inundation response classification system could be applied to ephemeral playas in other arid and semiarid landscapes.

  PublisherOA PDFDOI

• Global Destocking Trends and Their Consequences for Ecosystem Primary Productivity

  2026-03-14

  articleOpen accessCorresponding

  Grazing by livestock is the most extensive land use on Earth, covering nearly 40% of the terrestrial surface, and is commonly portrayed as a major driver of global land degradation in drylands through overgrazing. Yet, the role of grazing livestock as a driver of global environmental change remains poorly addressed in Earth-system research.In the first part of the presentation, we synthesize emerging global evidence to document the widespread and largely overlooked process of extensive livestock destocking and discuss its implications for ecosystem functioning. We show that regions containing 42% of grazing livestock species are experiencing reductions in stocking rates, while stocking rates continue to increase in other regions. This duality of increasing and decreasing stocking rates challenges the prevailing focus on overgrazing in research and calls for a more nuanced understanding of extensive livestock systems and their role in global environmental change.Because grazing livestock is the dominant consumer of terrestrial primary productivity, global destocking can affect biodiversity, fire regimes, carbon sequestration, and land–atmosphere fluxes at large scales. In the second part, we present a regional case study from peninsular Spain showing that recent changes in extensive stocking rates have modulated both greening and browning patterns at large scales. In the most common situation, declines in extensive livestock have produced measurable increases in ecosystem productivity. In medium-to-highly destocked rangelands, destocking accounts for approximately 6% of the observed increase in net primary productivity over the last two decades.Together, these findings demonstrate that extensive destocking is a relevant and underappreciated land-use driver of global change in drylands and highlight the need to rethink research and policy priorities around global grazing systems.

  PublisherDOI

• Drought intensity and duration interact to magnify losses in primary productivity

  Science · 2025-10-16 · 34 citations

  articleOpen access

  As droughts become longer and more intense, impacts on terrestrial primary productivity are expected to increase progressively. Yet, some ecosystems appear to acclimate to multiyear drought, with constant or diminishing reductions in productivity as drought duration increases. We quantified the combined effects of drought duration and intensity on aboveground productivity in 74 grasslands and shrublands distributed globally. Ecosystem acclimation with multiyear drought was observed overall, except when droughts were extreme (i.e., ≤1-in-100-year likelihood of occurrence). Productivity losses after four consecutive years of extreme drought increased by ~2.5-fold compared with those of the first year. These results portend a foundational shift in ecosystem behavior if drought duration and intensity increase, from maintenance of reduced functioning over time to progressive and profound losses of productivity when droughts are extreme.

  PublisherOA PDFDOI

• Data and metadata for: Tropical, arctic and anthropogenic biomes vary in key environmental threats: Expert perspective (Manuscript ID: FEE25-0297)

  Zenodo (CERN European Organization for Nuclear Research) · 2025-12-19

  datasetOpen accessSenior author

  This dataset contains the underlying data for the manuscript: "Tropical, arctic and anthropogenic biomes vary in key environmental threats: Expert perspective" (Manuscript ID: FEE25-0297), submitted to Frontiers in Ecology and the Environment. The repository includes the following files: Responses_Global_Survey - FEE25-0297: Anonymized raw data from the global expert survey. Metadata - FEE25-0297: A detailed data dictionary containing Variable IDs, survey section, full survey questions, and encoding notes. Respondents_by_country - FEE25-0297: A summary table of the geographic distribution of the experts who participated in the study. These files provide the necessary information to understand the survey structure and the resulting data used for the analysis of environmental threats across different biomes.

  PublisherDOI

• Author response for "Biocrust Mosses and Cyanobacteria Exhibit Distinct Carbon Uptake Responses to Variations in Precipitation Amount and Frequency"

  2025-03-12

  peer-review
  PublisherDOI

Recent grants

• Workshop: Abrupt grass-woodland transitions: Determinants and consequences for ecosystem services - December 15-17, 2012 in Maldonado, Uruguay

  NSF · $50k · 2012–2013

• Collabortive Research: Water availability controls on above-belowground productivity: Herbivory versus plant response

  NSF · $590k · 2015–2020

• LTREB: Long-term ecosystem responses to directional changes in precipitation amount and variability in an arid grassland

  NSF · $520k · 2018–2025

• DISSERTATION RESEARCH: Vegetation structure constraints on ANPP in arid ecosystems: Assessing the meristem limitation hypothesis

  NSF · $15k · 2009–2010

• Precipitation Controls of Carbon and Nitrogen Cycles in Arid-Semiarid Ecosystems

  NSF · $799k · 2009–2013

Frequent coauthors

• Laura Yahdjian

  Agricultural Plant Physiology and Ecology Research Institute

  58 shared

• Ana L. Scopel

  Institute of Astronomy and Space Physics

  58 shared

• Amy T. Austin

  Agricultural Plant Physiology and Ecology Research Institute

  46 shared

• Debra P. C. Peters

  Agricultural Research Service

  44 shared

• José M. Paruelo

  Instituto Nacional de Investigación Agropecuaria

  44 shared

• William K. Lauenroth

  Yale University

  40 shared

• Oumarou Malam Issa

  Sorbonne Université

  34 shared

• Carlos L. Ballaré

  Consejo Nacional de Investigaciones Científicas y Técnicas

  34 shared

Education

• Ph.D.

  Colorado State University

Awards & honors

• Elected member of the American Academy of Arts and Sciences
• Member of the Argentinean National Academy of Sciences
• Member of the Argentinean National Academy of Physical and N…
• Fellow of the Guggenheim Foundation
• Fellow of the American Association for the Advancement of Sc…