Wolverines Boreal Biodiversity

Wolverine density, survival, and population trends in the Canadian boreal forest

Scrafford, M., Seguin, J., McCaw, L., Boyce, M. & Ray, J.


Abstract

There is limited information available on wolverine (Gulo gulo) population density and trends in the boreal forest of North America. We estimated wolverine density using spatial capture-recapture methods across 2 boreal forest study areas in Red Lake, Ontario (26,568 km2) and Rainbow Lake, Alberta (19,084 km2), Canada. We also used radio-telemetry data to estimate annual survival of adult and sub-adult wolverines and evaluated population trends with a stage-based matrix model. We used an array of run poles and live traps to detect wolverines. In Red Lake over 3 winter field seasons (2019–2022), we detected 56 individual wolverines (17 females, 32 males, and 7 unknown sex), and in Rainbow Lake over 2 field seasons (2014–2016), we detected 48 individuals (19 females, 18 males, and 11 of unknown sex). Average densities in Red Lake and Rainbow Lake were 3.64 and 6.74 wolverines/1,000 km2, respectively. Adults and sub-adults occurred at equal abundance. Spring snow cover, roads, and industrial developments were not associated with spatial patterns of wolverine density. Most deaths occurred near roads; wolverines were killed in fur traps set along roads, by wolves using roads to travel, and by vehicles. The largest source of death was from incidental (n = 6 in Red Lake) or licensed fur trapping (n = 8 in Rainbow Lake) and we report 8 injuries from fur trapping sets. Red Lake survival estimates for adults (0.87) and sub-adults (0.86) contributed to a stable population trend. Rainbow Lake survival estimates for adults (0.66) and sub-adults (0.50) contributed to a declining population trend based on a relatively low sample of radio-days. Red Lake and Rainbow Lake combined survival estimates for adults (0.77) and sub-adults (0.73) also contributed to a declining population trend.

Key points

Recommended citation

Scrafford, M., Seguin, J., McCaw, L., Boyce, M. & Ray, J. (2024). Wolverine density, survival, and population trends in the Canadian boreal forest. Journal of Wildlife Management. https://doi.org/10.1002/jwmg.22587

Matthew Scrafford

Matthew Scrafford

Wolverine Conservation Scientist

Laura McCaw

Laura McCaw

Wolverine Research Associate

Justina Ray

Justina Ray

President & Senior Scientist

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