Integrating Fine-Scale Soil Data into Species Distribution Models

Fine-scale soil (SSURGO) data were processed at the county level for 37 states within the eastern United States, initially for use as predictor variables in a species distribution model called DISTRIB II. Values from county polygon files converted into a continuous 30-m raster grid were aggregated to 4-km cells and integrated with other environmental and site condition values for use in the DISTRIB II model. In an effort to improve the prediction accuracy of DISTRIB II over our earlier version of DISTRIB, fine-scale soil attributes replaced those derived from coarse-scale soil (STATSGO) data. The methods used to prepare and process the SSURGO data are described and geoprocessing scripts are provided.