Diet and habitat selection of gray wolves (Canis lupus) during the boreal caribou (Rangifer tarandus caribou) calving season in the southern Northwest Territories

Understanding the dietary habits of a species is crucial for studying ecosystem dynamics, and it becomes particularly important to understand the role of predators when prey populations become threatened. Prey are affected by predators via direct predation, indirectly through trophic cascades, and ultimately through the element of fear which influences the behaviour of prey. As an opportunistic predator, the gray wolf (Canis lupus) will often consume prey that are both numerous and vulnerable; however, wolves also adapt their diet and focus hunting efforts on ungulate prey in most of their range. Wolves are territorial, have large yearly home ranges, and become central place foragers during the denning period when pups are less mobile, often seeking habitats of higher quality to access valuable resources. The distribution of prey, den site selection, shelter, and anthropogenic features are all factors that may influence both diet and habitat selection of wolves. Therefore, my main objectives were to: 1) examine the diet of wolves in the southern Northwest Territories, Canada during the boreal caribou (Rangifer tarandus caribou) calving period as they are considered a threatened species and 2) develop habitat selection models using resource selection functions for wolves during both the denning period and annually. For my diet analyses, I used two methods: macroscopic and genetic approaches to examine the variation in diet at den sites from 2016-2020. Beaver (Castor canadensis) was the main prey in both frequency of occurrence and biomass consumed from the macroscopic analysis. White-tailed deer (Odocoileus virginianus) was the main prey by frequency of occurrence and moose (Alces alces) composed the largest portion by biomass with the genetic analysis. Habitat selection models were developed using data combined from 16 wolves tracked by satellite telemetry from 2016-2021. I analysed habitat selection in two groups of wolves: those associated with a den and those not associated with a den. For denning wolves, the top-performing model was the combined model, indicating selection for broadleaf-dense forests, non-vegetated areas, mixed wood-dense forests, steeper slopes, lower densities of linear features, proximity to roads, proximity to water, lower elevations, and avoidance of human settlements. For non-denning wolves, the top-performing model was also the combined model, indicating selection for mixed-wood-open forests, broad-leaf-open forests, mixed-wood-dense forests, higher densities of linear features, steeper slopes, proximity to human settlements, lower elevations, proximity to water, and proximity to roads. Although the diet analysis did not indicate that boreal caribou is highly prevalent prey for wolves in the southern NT, my habitat selection analysis during the denning period did align with preferred caribou habitat, suggesting spatial overlap between wolves and caribou that could increase encounter rates. This study will inform wildlife managers about habitat selection by wolves and possible impacts on prey.

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