Thesis Defence: Informing the Management of Grizzly Bear (Ursus arctos horribilis) Viewing in the Declared Title Area of the Tŝilhqot’in Nation
February 27 at 2:00 pm - 6:00 pm
Levi Oostenbrink, supervised by Dr. Mathieu Bourbonnais, will defend their thesis titled “Informing the Management of Grizzly Bear (Ursus arctos horribilis) Viewing in the Declared Title Area of the Tŝilhqot’in Nation” in partial fulfillment of the requirements for the degree of Master of Science in Earth and Environmental Sciences.
An abstract for Levi Oostenbrink’s thesis is included below.
Defences are open to all members of the campus community as well as the general public. This defence will be offered in a hybrid format. Registration is not required to attend in person; however, please email mathieu.bourbonnais@ubc.ca to receive the Zoom link for this defence.
Abstract
Wildlife viewing is typically considered a non-consumptive ecotourism activity; however, it can significantly alter animal behaviour. Wildlife viewing can trigger antipredator responses and risk-avoidance strategies which may lead to displacement from high-quality habitat and increased human-wildlife conflict when recurrent. Being one of the most sought-after species in British Columbia, the viewing of grizzly bears (Ursus arctos horribilis) has attracted attention from researchers, land managers, and Indigenous nations who seek to understand how viewers may impact bears and their access to salmon. With limited research examining the impacts in British Columbia, managing the effects of bear viewing on grizzly bear populations remains challenging. This research quantifies the effects of boat-based bear viewing on grizzly bear family groups and solitary individuals in the upper Chilko River corridor, a critical salmon-bearing ecosystem within the Tŝilhqot’in Nation’s Declared Title Area. Using remote camera trap data from 2021 to 2023, we employed Generalized Additive Mixed Models to analyze grizzly bear detection rates in relation to bear viewing metrics (boat counts and boat recency), resource availability (salmon counts), and other environmental variables.
Our findings revealed significant, subgroup-dependent behavioural responses to bear viewing, indicating that bear viewing shapes divergent activity patterns between subgroups. Solitary bears shifted to crepuscular activity, being less active at times and in locations with bear viewing, indicating risk-avoidance strategies. In contrast, family groups (females with young) demonstrated tolerance, concentrating activity during midday hours when viewing peaked and were most active with recent boat activity and in bear viewing locations. This behaviour is consistent with the human shield hypothesis, wherein family groups use the predictable presence of humans as a refuge from potentially infanticidal solitary males, who actively avoid human activity. Furthermore, salmon availability mediated these responses; solitary bears were most active when salmon counts were low, despite boat activity, indicating risk-tolerance to wildlife viewing when resources are scarce. These findings provide an empirical foundation for the Tŝilhqot’in National Government and the Province of British Columbia to develop nuanced, evidence-based regulations that ensure the sustainability of both the grizzly bear population and the local bear viewing industry.
