Distributions of sympatric canid species are shaped by intraguild competition and landscape complexity as modified by human activities. Much of midwestern North America is comprised of agricultural land uses interspersed with remnant patches of grassland and forest cover that may affect canid species differently. Although coyotes (Canis latrans), gray foxes (Urocyon cineorargenteus) and red foxes (Vulpes vulpes) are sympatric in the Midwest and throughout much of North America, little is known about large-scale influences of landscape pattern on relative abundance. To address this gap in the literature, we assessed whether landscape patterns in Illinois influenced the relative abundance of sympatric canids at the county scale. We determined relative abundance of canids using hunter-sighting data and quantified class- and landscape-level habitat variables for each county. Regression models were developed to determine which habitat variables affected relative abundance for (1) gray foxes only, and (2) coyotes vs. red foxes; top models were chosen based on AIC values.
Results/Conclusions For gray foxes, relative abundance was high in 37 of 102 (36%) counties in Illinois. Four variables were most important in explaining relative abundance for gray foxes. A wider range of shapes and sizes of agricultural patches and lower patch richness of the landscape resulted in lower relative abundance of gray foxes. Gray fox abundance was higher in counties containing high interspersion of grassland patches and larger forest patches in close proximity to one another. These results indicate that fragmentation of important forest and grassland cover types by agricultural land use negatively affected gray foxes. For the coyote vs. red fox analysis, coyotes were more abundant than red foxes in Illinois. Habitat variables explaining relative abundance differed mildly between species, suggesting that competition, namely coyotes outcompeting red foxes, may be a greater influence on species distributions. Our research provides baseline information regarding how habitat affects relative abundance of sympatric canids in a representative midwestern state and provides insight into how these species may fare in the future as habitat changes occur.
