Limited evidence for mesocarnivore release following wolf recovery in Wisconsin, USA

Restoration of top carnivore populations, such as gray wolves, may have many cascading effects on the ecosystems they inhabit. In many areas of North America without wolves, coyotes become dominant predators and can suppress the abundance of smaller carnivores such as foxes. Ecological theory and studies would suggest that recovering wolf populations could benefit foxes by limiting the abundance of coyotes and thus releasing foxes from the suppressive effects of coyotes. Using long-term (38 year) monitoring data, we evaluated the effects of recovering wolf populations on the abundance of coyotes and foxes in two regions of Wisconsin (USA). Overall, we found no evidence to support the hypothesis that increasing wolf populations limited coyote abundance, and instead found limited evidence that intrinsic density-dependence was more important to structuring coyote population growth based on model selection results. However, we did find some evidence to suggest that coyote populations are limiting fox population growth in one of our study regions. That wolves do not appear to limit coyote populations in Wisconsin could be the result of changing prey abundance and landscape configuration that favor coyotes, or the comparatively low wolf densities in Wisconsin as compared to areas where wolf effects on coyotes have been documented. We suggest that future research directly address the interactions among canids in the Great Lakes region, as there is large potential for cascading ecological effects as abundance of these species changes over time and space.