Spatiotemporal Patterns and Population Characteristics of Harvested Wolverine (Gulo gulo) in Yukon

• Author / Creator

  Kukka, Piia M.

• Wolverines (Gulo gulo) are harvested for fur in Yukon, Canada, but little is known about the sustainability of their harvest. In the absence of population data, harvest management relies on harvest data to assess the efficacy of regulations and harvest sustainability. I examined the spatiotemporal patterns of wolverine harvest in Yukon from 1988 to 2015. Overall, there was no significant trend in wolverine harvest over time, but harvest patterns varied regionally. Wolverine harvest was concentrated in southwestern Yukon, where mean annual harvest rates remained high (>10%) over time, indicating that harvest is likely sustained by immigration from harvest refugia. In contrast, wolverine harvest in eastern and northern Yukon was relatively low, and estimated harvest rates (<6%) suggest sustainable local harvest. Only 13% of licensed trappers, and 16% of traplines, reported wolverine harvest in a given year, indicating that wolverine was not a focal species for many trappers. Wolverine harvest is likely affected by the overall fur trapping and trapline utilization trends. However, individual behavior among trappers varied, with a few trappers appearing to focus on wolverines (25% of total wolverines were harvested by 3% of trappers), demonstrating that individual trappers have disproportionate effect on wolverine harvest patterns. Trapper motivation may be an important factor in wolverine harvest dynamics, particularly at regional scales. Demographic data collected from harvested wolverines provide information on the vulnerability and variability of different sex and age cohorts to harvest, which in turn, may have implications for harvest sustainability. I assessed the variability of different sex and age classes of harvested wolverines among years, and within the trapping season (early vs. late winter). I also documented basic reproductive parameters (e.g., litter size, pregnancy rates), and examined the potential implications of harvest timing on reproductive females. The overall harvest was skewed toward males and young individuals. The sex ratio of harvested animals did not fluctuate during the study, but I observed variation in the age structure among years. The age structure also varied within the harvest season, with a greater proportion of adults harvested in late winter. Most (81%) adult females were reproductively active when they were harvested. The timing of gestation varied, with expected parturition from mid-February to late March. The prominence of young males in the harvest suggests source-sink dynamics, where populations in harvested areas may largely consist of dispersing animals from harvest refugia in surrounding areas. Harvest during late winter is likely to have a more significant impact on populations than in the early winter, due to increased harvest of adults and susceptibility of denning females to harvest in late winter.

• Subjects / Keywords

  • Wolverine
  • Harvest management
  • Gulo
  • Yukon
  • Fur harvest

• Graduation date

  Spring 2017

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R30863J09

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.