Evaluating how stand level forest dynamics influence caribou winter range

• Other Authors: Hall, Erin (Author), Elkin, Che (Thesis advisor), Lilles, Erica (Committee member), Johnson, Chris (Committee member), University of Northern British Columbia (Degree granting institution)
• Format: Thesis
• Language: English
• Published: University of Northern British Columbia 2023
• Subjects: Alces alces; Rangifer tarandus
• Online Access: https://unbc.arcabc.ca/islandora/object/unbc%3A59425; https://doi.org/10.24124/2023/59425

Forest ecosystems and the ecological services they provide are complex and dynamic. Disturbance and successional processes impact habitat for animals such as caribou (Rangifer tarandus caribou Gmelin 1788, Banfield 1961, 1974) and moose (Alces alces L.). The forested winter habitat of the Tweedsmuir-Entiako caribou herd has been significantly affected by recent disturbance. In order to evaluate the mid- and long-term consequences for habitat, we require an understanding of how habitat attributes change as stand structure changes over time. I developed a framework to link a stand dynamics model (SORTIE-ND), via linker functions, to three ecosystem elements relevant to caribou populations: terrestrial forage lichen, moose forage, and vertical cover. I first used SORTIE-ND to model stand structure dynamics following mountain pine beetle (Dendroctonus ponderosae Hopkins) attack and clearcut harvesting. I developed linker functions and refined them with empirical data. These functions were applied to stand structure output from SORTIE-ND to project the response of habitat to the disturbance agents. I addressed three questions: 1. What is the influence of edaphic site on the provision of elements of caribou habitat over time? 2. What is the influence of stand type on the provision of elements of caribou habitat over time? 3. How do recovery trajectories of caribou habitat elements differ in response to disturbances such as mountain pine beetle and clearcut harvest? I found that site and stand type interacted to influence the suitability of terrestrial lichen, moose forage and vertical cover. Poor productivity sites were most favourable for terrestrial forage lichen. Higher productivity stands and broadleaf stands provided the greatest suitability for moose shrubs. Both mountain pine beetle attack and clearcut harvest improved stand suitability for lichen and moose browse though for different sites and stand types. Interestingly, I found that severe mountain pine beetle attack resulted in conditions that favoured ...