- 19 views
- 46 downloads
Simulated impacts of black bear predation on neonatal loss in boreal caribou
-
- Author / Creator
- Horne, Liam Gleason
-
Boreal caribou (Rangifer tarandus caribou) populations are declining across their range and the direct cause is predation. Black bears (Ursus americanus) can be significant predators of caribou neonates, but at high black bear densities in the boreal forest only a small proportion of bears could kill neonates without extirpating them. Bear predation is likely driven by bear density and spatial overlap with caribou neonates, but the interactive effect of density and overlap on predation rates is poorly understood. Using a simulation parameterized by empirical black bear and caribou data, we assessed i) how bear movement, habitat use, and density interact to influence predation on caribou neonates, and ii) whether caribou spatially separate from bears during calving to reduce predation risk (spatial separation hypothesis). We placed simulated neonates (≤2 weeks old) in either high-quality calving habitat or throughout caribou range. Neonates remained immobile and were killed when the movement paths of GPS-collared bears came within a specified detection distance. Simulations indicated that individual bears rarely kill neonates, but high-density bear populations can cause high neonatal mortality. However, reducing bear density did not result in a proportional reduction in predation. Bears were less likely to kill neonates in high-quality calving habitat than neonates with no habitat preference, supporting the spatial separation hypothesis. We emphasize the importance of predator density estimates to understand and effectively manage predation in systems with low-density, secondary prey such as boreal caribou. Removing bears is likely not an effective strategy to reduce bear predation on boreal caribou neonates. Future studies should aim to improve our understanding of how landscape alteration may affect bear demography.
-
- Graduation date
- Spring 2024
-
- Type of Item
- Thesis
-
- Degree
- Master of Science
-
- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.