Influence of nutrition on the habitat selection of the Ronald Lake wood bison (Bison bison athabascae) herd
Creators: Hecker, Lee
Publisher: name: University of Alberta Library
Year: 2022

<p>Acquiring food is a key component of what it means to be an animal. A significant portion of any animal’s life is spent locating, acquiring, consuming, and digesting food. Nearly every aspect of their life is influenced by it. The nutritional quality varies depending on foraging strategy and is a key component of what has led to the diversity of modern physiologies. The key factors influencing habitat selection are quantity, quality, and distribution of food, avoiding becoming food (i.e., predation), and competing with others for food. For wildlife managers, understanding how habitat selection results from making tradeoffs between these factors is key to making effective management decisions. In this dissertation, I explored how the nutritional components of food influence the habitat selection of an ungulate, wood bison, within a heterogeneous landscape to inform their management and conservation. The Ronald Lake wood bison (Bison bison athabascae) are a genetically distinct and disease-free wild population that are culturally significant to local Indigenous communities. They are located at the northern edge of Alberta’s oil-sands region subjecting their range to natural resource exploration and extraction. Since the herd’s diet is not well understood I started by conducting a review of the literature on bison diets and explored geographic trends in diet composition and macro-nutrition. I showed that at higher latitudes bison consume more woody plants and acquire more proteins and lipids. I then used this information to make predictions about the Ronald Lake bison’s diet and nutritional targets. The results demonstrate a seasonal switching from grazing in the winter and spring to more browsing during summer. Bison were able to maintain a specific nutrient composition between spring and summer despite differences in diet, demonstrating an ability to maintain nutritional targets. Next, I examined how selecting habitats for different behaviors is influenced by nutrition. Bison selected foraging sites with plants that had more crude protein and more digestible energy and while traveling they selected locations with plants that have more protein. Lastly, I assessed phenological factors motivating females to migrate to a distinct meadow during spring. This period likely aligns with parturition, which suggests the bison may be migrating to a calving site. I compared the non-mutually exclusive hypotheses that migration is a result of the green-up of vegetation (i.e., green-wave hypothesis) or that migration is a tactic to avoid predation pressure. I found support for the green-wave hypothesis as the timing of migration and habitat selection during migration were both influenced by the vegetation’s phenology. The start of migration to the meadow was most closely tied to peak of spring green-up and bison arrived at the meadow close to the end of green-up. Additionally, habitats selected during migration were closer to the peak of green-up at that location, suggesting selection for habitats with more readily digestible plants that contain more protein. Collectively, the results of my dissertation will inform the management of the Ronald Lake bison and help to mitigate the influence of future natural resource extraction on their range. Further, my work highlights the importance of considering the influence of nutrition on multiple components of an animal’s life, not just their foraging habits.</p>