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Recoverability and Vulnerability of Desert Ecosystems
The USGS Recoverability and Vulnerability of Desert Ecosystems (RVDE) project is an interdisciplinary research effort designed to provide land managers with the scientific understanding needed to conserve and restore the threatened Mojave Desert ecosystem. Because it is home to numerous Department of Interior and Department of Defense land units and is near several large urban areas, the Mojave Desert has been under increasing pressure from recreational and military activities, mining, and grazing. This research project seeks to determine the influence of various environmental factors on ecosystem vulnerability and recovery and to provide a deeper understanding of the characteristics and dynamics of the arid land ecosystems in the Southwest United States, with results applicable to arid systems around the globe. Research activities have included (1) mapping and modeling current physical and biological conditions on the landscape; (2) studying historical conditions and disturbances to evaluate how the landscape has responded; (3) researching landscape processes to understand how the land responds to or recovers from disturbance; and (4) combining all of this knowledge into maps and models of the vulnerability of the land and the time required to recover from disturbance. Research to date has focused on soil processes (compaction, erosion, biological soil crusts), and vegetation dynamics (natural dynamics and recovery from disturbance).
Western Region Geography’s participation in this project includes the following activities:
 Land Use History – In order to understand the impacts of human activities on the Mojave Desert ecosystem, scientists need information on how the ecosystem has been used in the past. Information derived from historical maps was placed in a land use history database that includes data on roads, grazing, military impacts, mining, and water sources.
Remote Sensing Techniques for Model Development – Soil and vegetation processes related to recovery and vulnerability are dependent on specific landscape variables such as surficial geology, soil texture, soil moisture, and vegetation type and percent cover. Developing geospatial maps of these input variables requires a combination of collecting data on the ground, modeling, and use of remote sensing. WRG scientists are using various types of remotely sensed imagery to provide input data for soil moisture modeling (for example, MODIS snow cover) and mapping of percent vegetation cover (using, for example, Landsat TM and MODIS EVI). Remote sensing techniques will be developed to map landscape variables in areas of detailed ground-condition knowledge so that the recovery and vulnerability models can be applied in other areas where detailed mapping of certain variables may not exist.
Geospatial Modeling of Vulnerability and Recovery - The RVDE project is developing models of vulnerability for soil compaction, wind erosion, and biological soil crusts, and recovery times for vegetation (example) and soil compaction (example). Developing geospatial models of these processes involves applying quantitative equations derived from experimental studies of the processes to the relevant landscape variable maps. These models will be linked via a user-friendly interface into a tool that can be used by land managers to analyze the vulnerability of an area to disturbance, and predict landscape recovery times once disturbed.
Point of Contact: Leonard Gaydos
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