A5000868264- Plant Water Relations and Carbon Dynamics
- Ecology and Vegetation Dynamics Studies
- Plant responses to elevated CO2
- Plant and animal studies
- Hydrology and Watershed Management Studies
- Tree-ring climate responses
- Climate variability and models
- Rangeland and Wildlife Management
- Geology and Paleoclimatology Research
- Forest ecology and management
- Species Distribution and Climate Change
- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Soil Carbon and Nitrogen Dynamics
- Fire effects on ecosystems
- Peatlands and Wetlands Ecology
- Soil erosion and sediment transport
- Soil and Unsaturated Flow
- Plant Parasitism and Resistance
- Aeolian processes and effects
- Cryospheric studies and observations
- Botany, Ecology, and Taxonomy Studies
- Botany and Plant Ecology Studies
- Plant Stress Responses and Tolerance
- Soil and Water Nutrient Dynamics
University of California, Irvine
2014-2024
University of Arizona
2007-2019
NSF National Center for Atmospheric Research
2010
Universidad de Antioquia
2009
United States Geological Survey
2007
Arizona Geological Survey
2007
University of Colorado Boulder
2000-2005
University of Tennessee at Knoxville
2005
University of Nevada, Las Vegas
1998-2001
University of Colorado System
2001
Large-scale biogeographical shifts in vegetation are predicted response to the altered precipitation and temperature regimes associated with global climate change. Vegetation have profound ecological impacts an important climate-ecosystem feedback through their alteration of carbon, water, energy exchanges land surface. Of particular concern is potential for warmer temperatures compound effects increasingly severe droughts by triggering widespread via woody plant mortality. The sensitivity...
Changes in Earth's surface temperatures caused by anthropogenic emissions of greenhouse gases are expected to affect global and regional precipitation regimes. Interactions between changing regimes other aspects change likely natural managed terrestrial ecosystems as well human society. Although much recent research has focused on assessing the responses rising carbon dioxide or temperature, relatively little understanding how respond changes Here we review predicted regimes, outline...
Increases in the abundance or density of woody plants historically semiarid and arid grassland ecosystems have important ecological, hydrological, socioeconomic implications. Using a simplified water-balance model, we propose framework for conceptualizing how plant encroachment is likely to affect components water cycle within these ecosystems. We focus particular on streamflow partitioning evapotranspiration into evaporation transpiration. On basis this framework, suggest that processes are...
How biological diversity is generated and maintained a fundamental question in ecology. Ecologists have delineated many mechanisms that can, principle, favor species coexistence hence maintain biodiversity. Most such require or imply tradeoffs between different aspects of performance. However, it remains unknown whether simple functional underlie diverse natural systems. We show explain differences long-term population dynamics are associated with recovery from low density (and coexistence)...
Leaf seasonality in Amazon forests Models assume that lower precipitation tropical means less plant-available water and photosynthesis. Direct measurements the Amazon, however, show production remains constant or increases dry season. To investigate this mismatch, Wu et al. use tower-based cameras to detect phenology (i.e., seasonal patterns) of leaf dynamics tree crowns Amazonia, Brazil, relate patterns CO 2 flux. Accounting for age-dependent variation among individual leaves is necessary...
Abstract We studied net ecosystem CO 2 exchange (NEE) dynamics in a high‐elevation, subalpine forest Colorado, USA, over two‐year period. Annual carbon sequestration for the was 6.71 mol C m −2 (80.5 g ) year between November 1, 1998 and October 31, 1999, 4.80 (57.6 1999 2000. Despite its evergreen nature, did not exhibit uptake during winter, even periods of favourable weather. The largest fraction annual occurred early growing‐season; first 30 days both years. Reductions rate after were...
The role of time in ecology has a long history investigation, but ecologists have largely restricted their attention to the influence concurrent abiotic conditions on rates and magnitudes important ecological processes. Recently, however, improved understanding processes by explicitly considering effects antecedent conditions. To broadly help studying time, we evaluate length, temporal pattern, strength memory with respect current dynamics. We developed stochastic modelling (SAM) framework...
Aeolian processes affect the biosphere in a wide variety of contexts, including landform evolution, biogeochemical cycles, regional climate, human health, and desertification. Collectively, research on aeolian is developing rapidly many diverse specialized areas, but integration these recent advances needed to better address management issues set future priorities. Here we review literature their interactions with biosphere, focusing (1) geography dust emissions, (2) impacts, interactions,...
ABSTRACT Widespread, rapid, drought‐, and infestation‐triggered tree mortality is emerging as a phenomenon affecting forests globally may be linked to increasing temperatures drought frequency severity. The ecohydrological consequences of forest die‐off have been little studied remain highly uncertain. To explore this knowledge gap, we apply the extensive literature on effects harvest in combination with limited existing ecohydrology research develop new, relevant hypotheses. Tree results...
Summary Vegetation change is expected with global climate change, potentially altering ecosystem function and feedbacks. However, causes of plant mortality, which are central to vegetation understudied, physiological mechanisms remain unclear, particularly the roles carbon metabolism xylem function. We report analysis foliar nonstructural carbohydrates ( NSC s) associated physiology from a previous experiment where earlier drought‐induced mortality P inus edulis at elevated temperatures was...
Abstract Many regions on Earth are expected to become drier with climate change, which may impact nitrogen (N) cycling rates and availability. We used a meta‐analytical approach the results of field experiments that reduced precipitation measured N supply (i.e., indices mineralization), soil microbial biomass, inorganic pools (ammonium (NH 4 + ) nitrate (NO 3 − )), nitrous oxide (N 2 O) emissions. hypothesized O emissions would be relatively insensitive reduction reducing increase...
Annual precipitation in the central and southern warm‐desert region of North America is distributed climatologically between summer winter periods with two prominent dry them. We used energy carbon dioxide (CO 2 ) fluxes from eddy covariance along standard meteorological soil moisture measurements at a semiarid savanna Arizona, United States, to better understand consequences warm or cool season drought on ecosystem CO exchange these bimodally forced water‐limited regions. Over last 100...
Abstract Across many dryland regions, historically grass‐dominated ecosystems have been encroached upon by woody‐plant species. In this paper, we compare ecosystem water and carbon dioxide (CO 2 ) fluxes over a grassland, grassland–shrubland mosaic, fully developed woodland to evaluate potential consequences of encroachment on important processes. All three sites were located in the riparian corridor river southwest US. As such, plants these may access moisture at capillary fringe...
In water‐limited ecosystems, partitioning ecosystem‐scale evapotranspiration fluxes between plant transpiration and soil/canopy evaporation remains a theoretical technical challenge. We used the Biosphere 2 glasshouse to assess of across an experimentally manipulated gradient woody cover using continuous measurements near‐surface variations in stable isotopic composition water vapor ( δ H). Our technique employs newly‐developed laser‐based isotope analyzer Keeling plot approach for surface...
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