Changes in mesopredator-community structure in response to urbanization

Common raccoons (Procyon lotor (L., 1758)), Virginia opossums (Didelphis virginiana Kerr, 1792), and striped skunks (Mephitis mephitis (Schreber, 1776)) are common urban inhabitants, yet their relative demographic response to urbanization is unknown. Urbanization often affects community structure, and understanding these effects is essential in rapidly changing landscapes. We examined mesopredator-community structure in small and large patches of natural habitat surrounded by urban, suburban, or rural matrices. We created generalized logit models using road-survey and livetrapping data to examine effects of surrounding land use on proportions of opossums and skunks relative to raccoons, while accounting for effects of season and year and their interactions. For large sites, the land use x season model was chosen for both data sets, and occurrence of opossums and skunks relative to raccoons was higher at the rural site (P < 0.001 for all tests). For small sites, the land-use model best fit the road-survey data, with a higher occurrence of skunks relative to raccoons at the rural site (chi(2) = 21.06, df = 1, P < 0.001). However, the season model best fit the trapping data for small sites. Our data indicated that raccoons exhibited a greater demographic response to urbanization, suggesting that they exploit anthropogenic resources more efficiently. Although numerous reasons exist for disparity in anthropogenic-resource use, differences in intraspecific tolerance and the role of learning in foraging behaviors were best supported by our observations.