Dissertation Defence: Survival and Movements of Mule Deer (Odocoileus hemionus) in Southern British Columbia

Chloe Wright, supervised by Dr. Adam Ford, will defend their dissertation titled “Survival and Movements of Mule Deer (Odocoileus hemionus) in Southern British Columbia” in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biology.

An abstract for Chloe Wright’s dissertation is included below.

Examinations are open to all members of the campus community as well as the general public. Registration is not required for in person defences.

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ABSTRACT

Human induced landscape change has had a profound and lasting impact on the earth, leading to habitat destruction and biodiversity loss. Understanding and reversing the consequences of anthropogenic landscape change is a priority for wildlife managers. An important step in preserving biodiversity is protecting high quality habitat, which is often inferred through resource selection functions (RSFs) and does not include an explicit link between habitat and fitness, potentially leading to incorrect conclusions about what constitutes high quality habitat for a species.

In this dissertation, I evaluated the effects of landscape change on mule deer (Odocoileus hemionus) migration and survival in south-central British Columbia, Canada, and evaluated whether RSFs correlated with survival and therefore inferred habitat quality. Specifically, I studied deer spring migration in a forested ecosystem disturbed by timber harvesting, identified how exposure to landscape disturbances affected deer survival, and integrated resource selection functions and survival models to quantify habitat quality across seasons and ages. To meet these objectives, I placed global positioning system collars on 201 adult female mule deer, 270 fawns, and 134 neonates from 2018 – 2022.

I found that during spring migration, deer did not time their movements to match the pace of forage green-up, likely because green-up did not occur in a way that was conducive for tracking. Potentially, timber harvesting has created a mosaic of early and late green-up patches, affecting the order and timing of green-up. Additionally, I found mortality risk increased in the winter when deer used areas with higher road densities and deeper snow depths. I also found deer that used recent burns and cutblocks had a reduced mortality risk in the summer compared to those that used these disturbances less often.

Finally, I found that for neonates, fawns, and adults in the summer, selection positively correlated with survival, and RSFs accurately inferred habitat quality. However, for adults in the winter, I observed no relationship between predicted probabilities of use and survival. The common assumption that selection correlates with survival was not met for all deer, highlighting the importance of incorporating survival or fitness-based metrics into models that measure species habitat quality.