Cooperative Fish and Wildlife Research Units Program: Michigan
Education, Research and Technical Assistance for Managing Our Natural Resources

Human development has major implications for wildlife populations with urban-exploiters benefiting from human subsidized resources whereas urban-avoiders can vanish from the wildlife communities in highly developed areas. Therefore, understanding how the density of different species varies in response to landcover associated with human development can provide important insight into how wildlife communities are likely to change and provide a starting point for predicting the consequences of those changes. Here, we use estimated the population density of five common mesocarnivore species (coyote (Canis latrans), bobcat (Lynx rufus), red fox (Vulpes vulpes), raccoon (Procyon lotor), and Virginia opossum (Didelphis virginiana)) along an urban to rural gradient in a rapidly developing area of the United States. At each study site, we applied the random encounter model to data from motion-triggered cameras to calculate the density of our five focal species. We then evaluated variation in density for each species based on natural and anthropogenic landcover variables. Coyotes and raccoons occurred in the greatest densities in areas with high estimated anthropogenic noise, suggesting that both species are synanthropic and able to co-exist in areas of high human activity. High densities of these species in proximity to human activity has potential repercussions for wildlife-human conflict. Alternatively, Virginia opossum and red fox attained the greatest densities in open, developed areas (lawns, golf courses, cemeteries, and parks) and were absent (red fox) or rare (opossum) in natural areas. Opossum and red fox were capable of living alongside humans but did so by an association with these novel, human-created and maintained environments. We found no evidence that bobcat density varied along the urban to rural gradient studied but suggest that this may have been confounded by the small spatial scale of many of our sites in relation to this wide-ranging species. The density estimates we report here based on game camera data of unmarked animals were consistent with reports from the literature for these same species. Furthermore, our results show that several mesopredators attain very high densities in close proximity to humans which certainly has implications for increased conflict with humans and our pets, their role as predators in human-dominated environments, and the risk of disease transmission in and around people. Finally, our results show that the novel environments that spread with the human footprint support large numbers of mesopredators that may be absent or occur in low densities in undeveloped areas.