Application of Geospatial Modeling and Remotely Sensed Data for Rangeland Studies

The increasing availability of geospatial data and tools, including geographic information systems (GIS) for display and analysis, is providing opportunities to expand the use of computer models of rangeland production. One such model is SPUR (Simulation of Production and Utilization of Rangelands), which was initially released in 1987 and has subsequently been revised for use in a number of areas in the U.S., including rangelands of the Great Plains and the Great Basin. SPUR can be used as a decision support tool to evaluate hydrologic and erosion changes in response to management decisions, as well as vegetation growth and utilization by grazing animals. A spatially explicit implementation of SPUR (SESPUR) has been developed at the USDA-ARS Southwest Watershed Research Center in Tucson, Arizona, and is under evaluation for use in semi-arid rangelands of the southwest. The goal of SESPUR development is to utilize available geospatial information for accurate simulation of existing conditions and for development of scenarios of potential future conditions. Current work is focusing on the integration of remotely sensed data such as Landsat and MODIS-based LAI and soil moisture, as well as distributed hydrologic information from other spatial models such as SWAT (Soil and Water Assessment Tool) and KINEROS. Ongoing calibration and validation of SESPUR is based on historic and newly acquired data for the Walnut Gulch Experimental Watershed near Tombstone, Arizona.