Lucia Corral

Leibniz Institute for Zoo and Wildlife Research · Department of Ecological Dynamics

Understanding patterns of space-use by individuals, their distribution, and how they coexist with ecologically similar species is crucial to address various issues in ecology, evolution, conservation biology, and wildlife management. However, the study of such patterns challenging because the relationship among species and their environment is shaped by multiple ecological processes, many of which are acting at different scales, often in a hierarchical manner. In the Canidae family, for instance, where interference competition appears critical, larger species such as coyotes (Canis latrans), can often affect smaller species, such as red fox (Vulpes vulpes) and swift fox (Vulpes velox), by killing or displacing foxes. As such, increases in the abundance and distribution of coyote following the development of the western Nebraska may have inadvertently restricted the range of swift fox (state endangered species) despite the availability of suitable habitat. In this study we aimed (1) to understand how land cover variables were associated with species occurrence and test the effect that presence of intraguild competitors have on the predictive distribution of the focal species (swift fox); (2) to investigate if temporal segregation among species may be the mechanism allowing their coexistence; and (3) to assess the genetic structure and diversity of swift fox population in Nebraska and explored whether or not genetic structure could be influenced by landscape feature and habitat constraints. Overall, our results reiterated the importance of native shortgrass prairies, at small scale, for the occurrence and distribution of swift fox, and showed that increases of tree, row-crops, and developed areas, at larger scales, would have negative effects on the species’ occupancy. Intraguild interactions do not seemed to be a significant force affecting swift fox occupancy. We found seasonal differences in activity patterns overlap among species and that differences in canid body size can predict the degree of their temporal separation. Our result suggest that swift fox population in Nebraska is restricted to two subpopulations within its available habitat, but without clear genetic structure and geographic isolation; gene flow among populations is occurring within Nebraska and across the larger region. However, our findings draw attention to the potential for future reduction of genetic diversity due to swift fox small population size in light of increasingly diminished and fragmented suitable habitat.