- 547 views
- 510 downloads
Grizzly bear population dynamics across productivity and human influence gradients
-
- Author / Creator
- Clayton T. Lamb
-
Coexistence with large carnivores is one of the greatest conservation challenges across the globe, in part because mechanisms of coexistence are unknown or contested. Large carnivores can be conflict-prone and pose real or perceived threats to human life and property. In North America, grizzly bears (Ursus arctos) typify the struggle to conserve and coexist with large carnivores amongst a matrix of competing land uses. Grizzly bears are a symbol of wildness to society, but the management of this species can divide communities, derail collaborative conservation initiatives, and are the focus of high-profile media coverage and lawsuits. At the center of this controversy is scientific uncertainty around population dynamics of the species, primarily relating to population size, limiting factors, and the ecology of conflict. The contemporary threats of wilderness loss, human population expansion, and climate change pose both a no-analog future for grizzly bears, but also opportunity. Leveraging novel ecological tools, and the ongoing human-induced landscape and climate change, considerable opportunity exists to investigate the mechanisms driving grizzly bear population dynamics and those promoting coexistence—enduring populations of wildlife in human-dominated landscapes. The goal of this dissertation was to test the factors limiting grizzly bear population dynamics across ecosystems, update local population estimates, and to identify the mechanisms promoting carnivore coexistence and those exacerbating it. Here I leverage 40 years of demographic data on grizzly bears collected across ecosystems to investigate hypotheses around grizzly bear population dynamics across productivity and human influence gradients in British Columbia (BC). This work provides multiple lines of evidence that grizzly bear populations purportedly coexisting in human-dominated landscapes are highly reliant on demographic rescue (immigrants) from adjacent wilderness areas. This source-sink dynamic is exacerbated when attractive habitat decouples the link between habitat quality and fitness, resulting in an ecological trap. Human influences such as human population density and road density have the potential to create strong, top-down limiting forces on bear populations that dwarf bottom-up influences. However, much of British Columbia is not permanently occupied by people, and the majority of grizzly populations across the province are bottom-up limited. Considerable potential exists to ensure the conservation and coexistence of bears is a success if evidence-based mitigation is executed collaboratively and equitably. I provide insight into the response of bear density to the mitigation measures for road density and highlight several cases where evidence from this dissertation lead to meaningful conservation action that will benefit bears and a variety of wildlife inhabiting similar areas. Collectively, this dissertation provides strong inference into the spatial structure and drivers of grizzly bear population dynamics across ecosystems and suggests that data generated for applied problems can be leveraged to test theory while informing applied problems at massive spatial extents.
-
- Graduation date
- Spring 2020
-
- Type of Item
- Thesis
-
- Degree
- Doctor of Philosophy
-
- License
- Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.