Multi-scale habitat selection model assessing potential gray wolf den habitat and dispersal corridors in Michigan, USA

Abstract

Following decades of absence, the gray wolf (Canis lupus) has recolonized much of the northern Great Lakes region from Canada and remnant populations in northern Minnesota. The wolf population in Michigan’s Upper Peninsula may now be reaching saturation, with evidence that some dispersing individuals have traversed the Straits of Mackinac during ice-over winter conditions indicating potential recolonization of northern Lower Michigan. While previous research suggests suitable habitat exists in northern Lower Michigan to support a small wolf population, habitat availability at other hierarchical levels, including den habitat and the ability of individuals to disperse successfully among suitable habitat patches, has not been assessed. We evaluated the den habitat availability and landscape connectivity using a multi-scale modeling approach that integrates hierarchical habitat selection theory as well as spatial structure to assess whether corridors exist for wolves to successfully recolonize and raise pups in northern Lower Michigan. We used expert opinion, scientific literature, and geographical information systems to develop models of landscape suitability, resistance, and least-cost path analysis to identify dispersal corridors throughout the Upper and northern Lower Peninsulas of Michigan. Based on our models, the Upper Peninsula was almost entirely amenable to wolves for both denning and dispersing, particularly in the western portion of the peninsula. Our estimates indicate that over 1900 km2 of high quality den habitat exists in northern Lower Michigan, but landscape permeability between these habitat patches appeared relatively low relative to Upper Michigan. We delineated several corridors of high quality habitat in the Upper Peninsula that may facilitate dispersal in to Lower Michigan. Dispersal corridors were of moderate quality in northern Lower Michigan, representing higher mortality risk but potentially capable of promoting recolonization of high-quality habitat areas. Conservation efforts within these identified corridors may further increase the potential for successful recolonization and establishment of viable long-term breeding populations of gray wolves in northern Lower Michigan.