Date of Award

Spring 1-1-2010

Document Type


Degree Name

Master of Science (MS)


Museum and Field Studies

First Advisor

Robert P. Guralnick

Second Advisor

David M. Armstrong

Third Advisor

Carol A. Wessman


Although it is acknowledged that species' occupancy at geographic range edges is likely dynamic and driven by shorter or longer-term extreme climate events, quantitative approaches that integrate spatiotemporal environmental dynamics with patterns in species' occupancy have been lacking. Here I show the utility of such integration. In this study I utilize data on climatic variability, previous records of occurrence, results from field surveys, and modeled spatial projections of climate suitability through time to make inferences about range edge dynamics for kit fox (Vulpes macrotis) at the north and east-most extent of the species' distribution in east-central Utah and west-central Colorado for the 27-year period, 1983 to 2009. My results elucidate the roles of mean climate suitability, spatial gradients in climate, and interannual weather variation on range limit formation and occupancy persistence. The novel approach used here is relevant to studies of population and range limit dynamics elsewhere.