“Wolverines are perhaps the most sensitive indicators of ecological integrity … due to biological characteristics and their dependence on large, connected ecosystems.” — Committee on the Status of Endangered Wildlife in Canada
Wolverine captured by citizen wildlife monitors in the North Cascades in 2012.
This tough and wide-ranging member of the weasel family is an iconic species that is recovering in our Cascadia region. As far back as the 1800s, records show that the Cascade Mountains were a home for wolverines. It is thought that wolverines disappeared from the America’s west coast in the early to mid-1900s, and that the North Cascades of Washington were later recolonized by individuals from British Columbia’s coastal ranges. At present, the Cascades is home to a resident population of wolverines with home ranges extending onto both sides of the Washington-BC border. Last spring researchers discovered reproducing wolverines south of I-90 in the Cascades, expanding our understanding of their distribution.
Inhabiting the area around the timberline, wolverines primarily restrict themselves to areas with spring snow cover. Estimates based on telemetry data suggest the Cascades population has significantly larger home ranges than other North American populations such as in the Rocky Mountains. Another difference between these two western mountain populations is their genetics – wolverines in the North Cascades share a genetic signature found in a number of Canadian populations, but missing from the American Rockies. Researchers in Washington and BC are working to better understand the genetics of our local population, and what they tell us about landscape scale connectivity patterns and needs for this species regionally.
Anticipated impacts from climate change are an obvious concern for the future of wolverine populations, given the close relationship between wolverine populations and deep, persistent snow depth. In addition to being a Priority Species of the Cascadia Partner Forum wolverines are a conservation target of the Great Northern Landscape Conservation Cooperative and a Climate WatchList Species in the Washington State Wildlife Action Plan (2015).
Models indicate this region is expected to maintain a well connected landscape with suitable habitat into the future, but much information is still needed on our transboundary resident population and habitat considerations to inform managers.
Activity areas of 7 radio-collared wolverines captured in the North Cascades of Washington (K. Aubry and C. Raley, U.S. Forest Service, unpubl. data).
Additional species resources
- Meet some of our Cascadian cast of wolverine characters (link downloads a PDF prepared by Cathy Raley of the PNW Research Station)
- North Cascades Wolverine video produced by the Skagit Environmental Endowment Commission on this unique transboundary species in the Cascades and coordinated transboundary research underway.
- February 2016 report: Wolverine distribution and ecology in the North Cascades ecosystem
- The Wolverine Foundation – a international website dedicate to sharing information on this species.
- US Fish and Wildlife Service wolverine webpage including proposed listing information.
- Climate change predicted to shift wolverine distributions, connectivity, and dispersal corridors. McKelvey et al, 2011.
- Course statewide scale connectivity models for wolverine produced by the Washington Wildlife Habitat Connectivity Working Group are available in the Washington Connected Landscapes Project: Statewide Analysis including maps, data layers, and a species background write up on wolverine (Pg. 127 of Appendix A).