Abstract:One-foot resolution imagery is used to develop a detailed land cover map for part of Highway 99 in the San Joaquin Valley of California, US. The land cover map is used to model the probability of occurrence of 12 endangered or threatened species and as input to an urban growth model to examine the likelihood of development of every map unit. The combination of the two model predictions permits the categorization of every map unit with a potential endangered species richness index and predicted degree of development. Polygons with high potential endangered species richness were ranked according to the degree of development pressure. This planning approach is computationally intensive, but the input data are relatively easy to assemble, consisting of: a detailed, and fine-scale, land cover map; species presence locations; statewide climate and landcover maps; a parcel ownership map; population growth projections; and a digital map of the county general plan.