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

• Published in: The Journal of Wildlife Management
• Main Authors: Scrafford, Matthew A., Seguin, Jacob L., McCaw, Laura K., Boyce, Mark S., Ray, Justina C.
• Other Authors: Alberta Conservation Association, R. Howard Webster Foundation, Donner Canadian Foundation, Echo Foundation
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2024
• Subjects: Canada; Red Lake; Gulo gulo; Rainbow Lake
• Online Access: http://dx.doi.org/10.1002/jwmg.22587

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 km 2 ) and Rainbow Lake, Alberta (19,084 km 2 ), 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 km 2 , 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. Our survival and population modeling suggests that human‐caused mortality is a significant risk to these populations. Our results can be applied to wolverine status assessments and used as benchmarks for future monitoring. ...