A large-scale regional assessment of suitable habitat for pygmy rabbits in southwestern Idaho

We tested a GIS-model developed to predict habitat suitability for the pygmy rabbit in a regional-scale analysis in Southwestern Idaho. Habitat was predicted to be suitable if big sagebrush was the dominant shrub type, the soil was <12.5% clay, slope was <15%, and aspect was between 0-120degrees or 300-360degrees. To assess the accuracy of the GIS-model, 137 sites (72 within predicted suitable habitat and 65 within predicted unsuitable habitat) were groundtruthed for presence of predicted soil and vegetation types. The GIS-model predicted suitable habitat with 80.5% accuracy and unsuitable habitat with 76.9% accuracy. The main factor limiting GIS-model performance was the accuracy of the vegetation layer. We also checked the 137 sites for pygmy rabbit activity to determine how well the GIS-model predicted use and non-use areas. The model predicted areas unused by pygmy rabbits (74%) better than areas used (42%). We concluded that the model is robust in predicting non-use areas and works adequately for predicting suitable and unsuitable habitat, but stress the need for accurate vegetation maps. Application of this model over the whole range of the pygmy rabbit would provide managers with a valuable tool in conserving this species.