The role of soil classification in geographic information system modeling of habitat pattern: Threatened calcareous ecosystems

Maps of potential habitat distribution are needed for regional population m odels of rare species, but reliable information from ground surveys is not always available. Existing data sources from disciplines other than ecologi cal research often are underused. In this article, we discuss the developme nt of a geographic information system (GIS) model that predicts potential h abitats from ecosystem information contained in the US soil classification and soil survey. Soil classification and survey were used in the GIS model in an earlier study on the US Department of Energy's Oak Ridge Reservation, Tennessee, to predict threatened calcareous habitats. The model predicts p otential habitats from the combination of (a) soil taxon as an indication o f long-term ecosystem processes; (b) geologic parent material; and (c) slop e class. Satellite imagery was added to indicate current successional state . In this study, we rested the model's predictive ability by using data fro m the Cedar Creek Slope Glades Preserve at the 44,000-ha US Department of D efense Fort Knox Military Reservation, Kentucky. We then used the model to predict occurrences of potential suitable habitat on the remainder of the F ort Knox reservation, including heavily impacted ordnance and tank training areas that are unsafe for public access; The soil component of the model a lso was applied to a 1.2 x 10(6)-km(2) region of the US, by using the US De partment of Agriculture-National Resources Conservation Service (USDA-NRCS) State Soil Geographic Database (STATSGO) combined with official soil serie s descriptions. Soil taxa from the USDA-NRCS Soil Taxonomy were demonstrate d to be associated with threatened calcareous habitats of rare plant specie s. These soil taxa were lithic mollisols (rendolls and udolls; Food and Agr iculture Organization of the United Nations (FAO) rendzinas and chernozems) and alfisols (udalfs; FAO luvisols). The combined soil/geology/slope GIS a pproach has potential for prediction of rare ecosystems with narrow edaphic constraints. The approach would be useful in long-term planning for conser vation management and restoration, especially where intensive ground survey s are expensive and/or impractical and where disturbance history obscures p atterns of historical distribution.