Habitat suitability models for desert amphibians
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A fundamental step in conserving biodiversity is identification of quality habitat needed to sustain populations of target species. We used coarse scale environmental features (soil water holding capacity, soil texture, slope, elevation, and proximity to drainage channels) to predict habitat suitability for four species of desert amphibians in Big Bend National Park, USA: Scaphiopus couchii, Bufo debilis, Bufo punctatus, and Gastrophryne olivacea. Habitat suitability models were evaluated using data from 7 years of breeding site surveys. Overall our models provide quantitative measures of reliability for where species are likely to occur; however, results varied among species. Suitable habitat for B. punctatus and G. olivacea extended over greater proportions of the study area and encompassed a wider variety of habitats compared to suitable habitat for S. couchii and B. debilis. Our models performed better at predicting where S. couchii and B. debilis were likely to occur compared to B. punctatus and G. olivacea. The variation in the predicted suitable habitat among these species, as well as the agreement between model output and breeding site use, elucidates the fact that developing single species habitat suitability models may be a more appropriate approach than trying to develop multi-species models. Our study provides the first habitat suitability models for desert amphibians and provides important information for conservation biologists and land managers concerned with preserving amphibian diversity in xeric landscapes. 2006 Elsevier Ltd. All rights reserved.