Rangeland Ecological and Physical Modeling in a Spatial Context

The Simulation of Production and Utilization of Rangelands (SPUR) model has been in use and revision since 1987 in diverse rangelands including Texas and the Great Plains. The model’s applicability to semi-arid rangelands of the southwest is under evaluation at the USDA-ARS Southwest Watershed Research Center in Tucson, Arizona. As part of this effort, a spatially explicit implementation of SPUR (SESPUR) has been developed with the long-term goal of incorporating distributed hydrologic information from GIS-based hydrologic models such as the Soil and Water Assessment Tool (SWAT) and KINEROS, as well as remotely sensed soil moisture. Ease of model use has been improved with the ability to display output with a GIS, and linkage to a database of input parameters will improve the user’s experience. Validation of the updated model is in progress with data obtained at the Walnut Gulch Experimental Watershed near Tombstone, Arizona. The original focus of SPUR included prediction of hydrologic and erosion changes resulting from management decisions, as well as simulation of forage growth and its utilization by grazing animals. Its usefulness for other biophysical and ecological modeling has been substantially enhanced with the SESPUR spatial implementation