Spatial Ecology of Bobcats in a Texas High Plains Ecosystem

ABSTRACT
I studied bobcats on and around the 7,289 ha Pantex Plant in Carson County, Texas. This region of the Southern High Plains is primarily shortgrass prairie and agricultural lands with minor topographic relief and little natural structure or vertical cover. I captured 23 individual bobcats a total of 34 times. Eleven of these individuals were females (8 adults) and 12 of the individuals were males (10 adults). Adults (age > 1 year) were fitted with a GPS-GSM collar. Radiotelemetry efforts resulted in 17,478 viable locations for the 13 bobcats used in home range and habitat selection analyses. Female 100% minimum convex polygon (MCP) home ranges ranged from 5,496 - 20,406 ha. Male home ranges ranged from 6,969 - 40,748 ha. There was no statistical difference between seasonal home range sizes (P = 0.779). I used compositional analysis to evaluate habitat selection at 2 spatial scales. For second-order selection, use was defined as the habitat within 100% MCPs generated around each bobcat’s radiolocations. Availability was defined as habitat within the study area which was an MCP that included all bobcat radiolocations. For third-order selection, use was defined by the habitat composition at each bobcat’s radiolocations and availability was defined as the habitat within each bobcat’s 100% MCP. I also investigated both second and third-order habitat selection for proximity to defined habitat types by calculating buffer increments for each habitat. For second-order selection, use was defined as the buffer increments within each bobcat’s 100% MCP while the habitat available was defined as the buffer increments within the study area. For third-order, use was defined as the proportion of relocations within each buffer increment while the buffer increments within the 100% MCP served as the habitat available. Bobcats demonstrated high preference for anthropogenically-impacted areas in third-order selection and high preference for prairie dog towns in second-order selection. They exhibited avoidance of roads and railroads in both second and third-order selection. Preference for anthropogenic areas is likely a response to the lack of natural structure in the area. The selection preferences for artificial habitat features and relatively large home range sizes may indicate a lower quality habitat for bobcats.