A GIS Model for Identifying Potential Breeding Habitat for the Houston Toad (Bufo houstonensis)




Buzo, Daniela

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Identification and characterization of suitable habitat is fundamental for modern conservation biology and wildlife management. Threatened and endangered species are excellent candidates for a landscape level approach to habitat suitability predictive models. I used soil type, canopy cover, and distance to water source as environmental variables to predict potential habitat for the endemic and highly endangered amphibian Bufo houstonensis. The accuracy of the models was evaluated by overlaying species occurrence data onto predictive habitat suitability maps. I used a chi-square goodness of fit test to examine whether the observed frequencies of occurrence in each habitat category were different than would be expected if they occurred in the categories relative to their availability. These categories were: High, Medium, Low, Very Low and None. Overall, model evaluation demonstrated that habitat suitability models performed well when predicting species occurrence in High and Medium suitable habitat categories and species absence in Very Low and None categories. This study provides important information for the recovery of Houston Toad. It enables the evaluation of surveys, identifies localities that are not currently occupied but appear to have suitable habitat, and aids in the selection of suitable re-introduction sites.



Bufo, habitat conservation, geographic information systems, amphibian declines


Buzo, D. (2008). A GIS model for identifying potential breeding habitat for the Houston Toad (Bufo houstonensis) (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.


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