Grizzly Bear Core Habitat and Corridors, Madison Valley, Montana

The Madison Valley is an important wildlife linkage zone between core habitats at the center of the Greater Yellowstone Ecosystem (GYE) and habitats at the western edge of the GYE and beyond. This report identifies lands in the Madison Valley watershed which are significant for conservation based on the common occurrence of key threats to wildlife and their critical habitats and migration corridors. The species emphasized in this report - grizzly bear, wolverine, and pronghorn antelope - were selected for their need to move across or along the valley to maintain traditional migration routes, enable genetic exchange across the valley, or expand into unoccupied habitat. The selected species are also intended to serve as umbrellas for other species with similar connectivity or habitat requirements, meaning that conservation efforts that are focused on these species will also likely benefit other species with similar needs. Connectivity models were derived using GIS, information gleaned from published literature, and expert opinion. The habitat models for grizzly bear and wolverine were used to develop least cost path (LCP) corridor maps to predict areas where animals were most likely to cross the valley from one mountain range to another. Pronghorn migration routes were mapped by Steve Primm using information collected from area land owners and wildlife experts.