Wolverine Harvest Summary from Registered Traplines in Alberta, 1985 - 2011
Shevenell Webb, Doug Manzer, Robert Anderson, and Michael Jokinen
Wolverines are among the most rare and least understood carnivores in the world. Lack of data has classified the status of wolverines as Data Deficient in Alberta. Large home ranges, low densities, and remote habitat use make wolverines challenging to study. Long-term trapping records are valuable and can be used to assess distribution and relative abundance. Previous studies have suggested that wolverine harvests and potential populations may be declining, but more recent data have not been analyzed. Thus, we completed a comprehensive update on long-term wolverine harvest trends in Alberta.
We used wolverine harvest data collected from fur affidavits (1985-2011), fur registrations (1989-2011), and Statistics Canada pelt export records (1971-2010). Our results show that the total number of registered traplines harvesting a wolverine in a year, and the average number of harvested wolverines, has increased since the early 1990s. The distribution of harvest data suggest that wolverines primarily occur in the Rocky Mountains, Foothills, Boreal Forest, and Canadian Shield natural regions of Alberta. When comparing two time periods (1989-1999; 2000-2011), wolverine harvests have more than doubled in the Northwest Boreal (105%) and increased in the Northeast Boreal (47%) and Foothills (33%), while declining in the Canadian Shield (40%) and Rocky Mountains (32%). However, it is not clear whether these results are related to changes in trapper effort, wolverine population, or other factors.
Some registered traplines in the Rocky Mountains had the highest wolverine harvest densities, but wolverines have been harvested the most consistently, over the past 23 years, in the Boreal Forest, primarily north of 58 degrees latitude (WMU 530, 536, 539). Despite a lack of consistent spring snow cover (thought to be a critical factor for wolverine occurrence), wolverine harvest success on some traplines in the Boreal Forest was moderately high, indicating that other factors may be responsible for wolverine persistence.
We also found a high spatial and temporal overlap between lynx and wolverine harvests, indicating that the number of lynx is possibly associated with the number of wolverine harvested each year. However, these results may also be related to trapper effort or other factors. We will be working with trappers to further investigate these trends as part of a larger project to determine wolverine occupancy and gene flow across Alberta.