Ecology and conservation of cougars in the eastern Great Basin: effects of urbanization, habitat fragmentation, and exploitation
Author(s): David C. Stoner
Author(s): David C. Stoner
Description: This research was designed to investigate cougar response to urbanization, habitat fragmentation, and exploitation from behavioral, demographic, and landscape perspectives. The source-sink model has been proposed as an alternative framework for the management of exploited cougar populations. I addressed the basic question of whether cougars conform behaviorally to the predictions of the source-sink model, and consequently, the applied question of whether the model could be used for the conservation of this species. To achieve this I evaluated three scale-specific questions using radio-telemetry and hunter-harvest data collected from 1996-2010. At the subpopulation scale, I tested the hypothesis that cougars are wildland obligates by measuring cougar response to a suite of anthropogenic land uses. At the meso scale I compared cougar dispersal patterns from two populations under different management. Lastly, at the statewide scale I examined the distribution of human-induced de facto refugia and ecological traps in relation to the species range within Utah. Cougars show a strong proclivity for wildland over rural or suburban habitats, but all cougars used anthropogenic landscapes to some degree, and appear capable of surviving in highly disturbed, human-impacted environments. Cougar dispersal was correlated with maternal estrus; once young animals emigrated, natural and anthropogenic barriers directed movement into habitats marked by frequent human-caused mortality, with females selecting areas of lower conspecific density relative to males. Anthropogenic cougar mortality was disproportionately distributed in accessible, high quality habitats within the core of the species statewide range. Conversely, ecological traps were primarily situated within marginal habitats in remote settings on the periphery of the range. The source-sink model predicts that subordinate animals from saturated populations disperse to habitat with the highest suitability. Cougars of both sexes display behaviors that largely conform to these predictions. Based on the patchy but predictable distribution of cougar exploitation, Utah may already have a quasi source-sink system, which could be formalized through management action. In general, cougars are adaptable, behaviorally plastic, generalist carnivores, and as such defy broad habitat generalizations. These investigations have implications for sustainable hunting and long-term conservation of cougars in the multiple-use landscapes of the Intermountain West.