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

Shawn M. Crimmins,Timothy R. Van Deelen

doi:10.2981/wlb.00511

Abstract

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.

Highlights

BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research
We found no evidence to support the hypothesis that increasing wolf populations limited coyote abundance, and instead found limited evidence that intrinsic densitydependence was more important to structuring coyote population growth based on model selection results
Models for fox population growth in the southern region appeared to be strongly influenced by coyote and wolf abundance based on model weights (Table 1)

Summary

Introduction

BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Ecological theory and studies would suggest that recovering wolf populations could benefit foxes by limiting the abundance of coyotes and releasing foxes from the suppressive effects of coyotes. Top–down influences of upper trophic levels on lower trophic levels are a widely studied phenomenon in ecology (Terborgh and Estes 2010) These cascading effects often are among the most important factors in structuring many ecological communities (Ripple et al 2014). These effects are identified in systems that contain at least three distinct trophic levels, with species occupying the highest level providing positive, indirect effects to those species occupying the lowest trophic level through limitations on the abundance of organisms in the intermediate trophic level. This effect has been seen in numerous mesocarnivore systems across the globe (Elmhagen et al 2010)

Methods

Results

Conclusion