A5003969258- Plant Water Relations and Carbon Dynamics
- Remote Sensing in Agriculture
- Rangeland and Wildlife Management
- Climate variability and models
- Species Distribution and Climate Change
- Remote Sensing and LiDAR Applications
- Atmospheric and Environmental Gas Dynamics
- Land Use and Ecosystem Services
- Hydrology and Watershed Management Studies
- Allergic Rhinitis and Sensitization
- Ecology and Vegetation Dynamics Studies
- Soil Carbon and Nitrogen Dynamics
- Agriculture Sustainability and Environmental Impact
- Plant Ecology and Soil Science
- Climate change impacts on agriculture
- Soil erosion and sediment transport
- Tree-ring climate responses
- Pasture and Agricultural Systems
- Plant responses to elevated CO2
- Hydrology and Drought Analysis
- Precipitation Measurement and Analysis
- Peatlands and Wetlands Ecology
- Water Quality Monitoring and Analysis
- Meteorological Phenomena and Simulations
- Phosphorus and nutrient management
University of Arizona
2011-2025
Louisiana Department of Natural Resources
2022
Southwest Watershed Research Center
2012-2020
Agricultural Research Service
2014-2019
United States Department of Agriculture
2014-2016
Chapman University
2011
University of Michigan
1969
Significance Global food and biofuel production their vulnerability in a changing climate are of paramount societal importance. However, current global model predictions crop photosynthesis highly uncertain. Here we demonstrate that new space-based observations chlorophyll fluorescence, an emission intrinsically linked to plant biochemistry, enable accurate, global, time-resolved measurement photosynthesis, which is not possible from any other remote vegetation measurement. Our results show...
Abstract Amplification of the hydrologic cycle as a consequence global warming is predicted to increase climate variability and frequency severity droughts. Recent large‐scale drought flooding over numerous continents provide unique opportunities understand ecosystem responses climatic extremes. In this study, we investigated impacts early 21st century extreme hydroclimatic variations in southeastern Australia on phenology vegetation productivity using Moderate Resolution Imaging...
Global-scale studies suggest that dryland ecosystems dominate an increasing trend in the magnitude and interannual variability of land CO2 sink. However, such analyses are poorly constrained by measured exchange drylands. Here we address this observation gap with eddy covariance data from 25 sites water-limited Southwest region North America observed ranges annual precipitation 100-1000 mm, temperatures 2-25°C, records 3-10 years (150 site-years total). Annual fluxes were integrated using...
Abstract Each year, terrestrial ecosystems absorb more than a quarter of the anthropogenic carbon emissions, termed as land sink. An exceptionally large sink anomaly was recorded in 2011, which half attributed to Australia. However, persistence and spatially attribution this remain largely unknown. Here we conducted an observation-based study characterize Australian through novel coupling satellite retrievals atmospheric CO 2 photosynthesis in-situ flux tower measures. We show 2010–11...
Rice is a staple food in East Asia and Southeast Asia—an area that accounts for more than half of the world’s population, 11% its cultivated land. Studies on rice monitoring can provide direct or indirect information security, water source management. Remote sensing has proven to be most effective method large-scale croplands, by using temporary spectral information. The Google Earth Engine (GEE) cloud-based platform providing access high-performance computing resources processing extremely...
Nutrient recycling is fundamental to sustainable agricultural systems, but few mechanisms exist ensure that surplus manure nutrients from animal feeding operations are transported for use on nutrient-deficient croplands. As a result, concentrate in locations where they can threaten environmental health and devalue as fertilizer resource. This study advances the concept of "manureshed" – lands surrounding onto which be redistributed meet environmental, production, economic goals. Manuresheds...
Most studies assessing chlorophyll fluorescence (ChlF) have examined leaf responses to environmental stress conditions using active techniques. Alternatively, passive techniques are able measure ChlF at both and canopy scales. However, the measurement principles of different, only a few datasets concerning relationships between them reported in literature. In this study, we investigated potential for interchanging measurements with different temporal spatial The ultimate objective was...
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 prolonged warm droughts more intense rainfall events predicted with climate change. The early 21st-century drought southwestern resulted hydroclimatic conditions that are similar those expected future We investigated impact of on aboveground net primary production (ANPP) six desert plains grasslands dominated by C4 (warm...
Abstract In the southwest United States, current prolonged warm drought is similar to predicted future climate change scenarios for region. This study aimed determine patterns in vegetation response early 21st century across multiple biomes. We hypothesized that different biomes (forests, shrublands, and grasslands) would have relative sensitivities both drivers (precipitation temperature) legacy effects (previous‐year's productivity). tested this hypothesis at eight Ameriflux sites various...
DATA REPORT article Front. Sustain. Food Syst., 15 February 2021 | https://doi.org/10.3389/fsufs.2020.612785
Abstract Studies conducted at sites across ecological research networks usually strive to scale their results larger areas, trying reach conclusions that are valid throughout enclosing regions. Network representativeness and constituency can show how well conditions sampling locations represent also found elsewhere be used help scale-up over Multivariate statistical methods have been design select optimize regional representation, thereby maximizing the value of datasets research. However,...
Effective measurement of seasonal variations in the timing and amount production is critical to managing spatially heterogeneous agroecosystems a changing climate. Although numerous technologies for such measurements are available, their relationships one another at continental extent unknown. Using data collected from across Long-Term Agroecosystem Research (LTAR) network other networks, we investigated correlations among key metrics representing primary production, phenology, carbon fluxes...
Abstract Dryland ecosystems are dominant influences on both the trend and interannual variability of terrestrial carbon sink. Despite their importance, dryland dynamics not well-characterized by current models. Here, we present DryFlux, an upscaled product built a dense network eddy covariance sites in North American Southwest. To estimate gross primary productivity, fuse situ fluxes with remote sensing meteorological observations using machine learning. DryFlux explicitly accounts for...
Integrating fine-scale measurements with broad-scale monitoring is a challenge for environmental monitoring, but it critical advancement in the face of increasing climate variability. We addressed this by integrating measures from Unoccupied Aerial Systems (UAS) to train satellite imagery via machine learning algorithms. applied integration detect how spatial patchiness bare ground varies over five years across 100 km² semi-arid landscape southern Arizona, USA. used Largest Patch...
Abstract Intra-annual precipitation patterns are expected to shift toward more intense storms and longer dry periods because of changes in climate within future decades. Using satellite-derived estimates plant growth combined with situ measurements soil moisture between 1999 2013, this study quantified the relationship intra-annual patterns, annual average (at 5-cm depth), at nine grassland sites across southern United States. Results showed a fundamental difference response varying mesic...
Abstract In adaptive management of rangelands, monitoring is the vital link that connects actions with on‐the‐ground changes. Traditional field methods can provide detailed information for assessing health but cost often limits locations to a few key areas or random plots. Remotely sensed imagery, and drone‐based imagery in particular, observe larger than while retaining high enough spatial resolution estimate many rangeland indicators interest. However, geographic extent drone products...
Agriculture and natural systems interweave in the southeastern US, including Florida, Georgia, Alabama, where topographic, edaphic, hydrologic, climatic gradients form nuanced landscapes. These are largely working lands under private control, comprising mosaics of timberlands, grazinglands, croplands. According to “ecosystem services” framework, these landscapes multifunctional. Generally, highly valued for their provisioning services, some degree cultural while regulating supporting...
Abstract During the 21st century, human–environment interactions will increasingly expose both systems to risks, but also yield opportunities for improvement as we gain insight into these complex, coupled systems. Human–environment operate over multiple spatial and temporal scales, requiring large data volumes of multi‐resolution information analysis. Climate change, land‐use urbanization, wildfires, example, can affect regions differently depending on ecological socioeconomic structures....
The Walnut Gulch Experimental Watershed (WGEW) Long-Term Agroecosystem Research (LTAR) network common experiment addresses the aspirational practice of brush management (BM) to reverse prevailing condition woody plant encroachment (WPE) and increase perennial native grass production. Across western United States, decision implement BM includes consideration objectives, cost, expected impact on a diverse suite ecosystem services. Maintaining or restoring cover will help meet LTAR sustainable...