Diet composition and prey selectivity of gray wolves (Canis lupus) in Prince Albert National Park, Saskatchewan

• Author / Creator

  Shave, Justin

• Plains bison (Bison bison bison) were nearly driven to extinction in the late 19th century due to overhunting and habitat loss, and populations occurring within their historic range and co-existing with natural predators are exceedingly rare. Studies examining gray wolf (Canis lupus) predation on wild, genetically-pure bison populations are limited to only a few areas in North America. We studied wolf predation on plains bison and other ungulates in Prince Albert National Park (PANP), Saskatchewan. The Sturgeon River plains bison (SRPB) are one of only a few wild populations of plains bison in their historical range in Canada, and have experienced a decline of around 50% since 2005. Disease and annual harvests contributed to past bison mortality, but the role of predation in the SRPB decline was unclear. We used stable isotope analysis to examine intra- and inter-annual variation in wolf diet to assess the importance of bison and other ungulates to wolves, relative to the decline of the SRPB. In addition, we measured hair cortisol concentrations (HCC) and marrow lipid content of wolf-killed prey to evaluate the link between chronic stress, body condition, and vulnerability to predation by gray wolves. We found greater variation in proportions of prey consumed by wolves during summer, in comparison to winter when white-tailed deer (Odocoileus virginianus) were the main prey. Wolves that had a higher degree of overlap with the SRPB range had more bison in their diet, particularly during winter. Wolf-killed bison had significantly higher HCC compared to human-harvested bison, and bison showed the strongest negative relationship between HCC and marrow lipid content in comparison to moose (Alces alces) and deer. Management of the SRPB population should be focused on reducing human-harvests, rather than wolf predation, to lower extinction risk and aid in population recovery.

• Subjects / Keywords

  • predator-prey dynamics
  • bison
  • diet
  • stress
  • gray wolf

• Graduation date

  Spring 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-tdt4-8h54

• License

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