Grizzly bear predation links the loss of native trout to the demography of migratory elk in Yellowstone

Middleton, A. D. et al. (2013) Grizzly bear predation links the loss of native trout to the demography of migratory elk in Yellowstone. Proceedings of the Royal Society of London Series B: Biological Sciences, 280(1762), 20130870. (doi: 10.1098/rspb.2013.0870) (PMID:23677350) (PMCID:PMC3673062)

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The loss of aquatic subsidies such as spawning salmonids is known to threaten a number of terrestrial predators, but the effects on alternative prey species are poorly understood. At the heart of the Greater Yellowstone ecosystem, an invasion of lake trout has driven a dramatic decline of native cutthroat trout that migrate up the shallow tributaries of Yellowstone Lake to spawn each spring. We explore whether this decline has amplified the effect of a generalist consumer, the grizzly bear, on populations of migratory elk that summer inside Yellowstone National Park (YNP). Recent studies of bear diets and elk populations indicate that the decline in cutthroat trout has contributed to increased predation by grizzly bears on the calves of migratory elk. Additionally, a demographic model that incorporates the increase in predation suggests that the magnitude of this diet shift has been sufficient to reduce elk calf recruitment (4–16%) and population growth (2–11%). The disruption of this aquatic–terrestrial linkage could permanently alter native species interactions in YNP. Although many recent ecological changes in YNP have been attributed to the recovery of large carnivores—particularly wolves—our work highlights a growing role of human impacts on the foraging behaviour of grizzly bears.

Item Type:Articles
Additional Information:A.D.M. and M.J.K. received support from the Wyoming Game and Fish Department, the Rocky Mountain Elk Foundation, the Wyoming Animal Damage Management Board and the Wyoming Governor's Big Game License Coalition. A.D.M. received additional support from the University of Wyoming's Program in Ecology, Biodiversity Institute, and NSF-EPSCoR programme (EPS-436 0447681).
Glasgow Author(s) Enlighten ID:Morrison, Dr Thomas
Authors: Middleton, A. D., Morrison, T. A., Fortin, J. K., Robbins, C. T., Proffitt, K. M., White, P.J., McWhirter, D. E., Koel, T. M., Brimeyer, D. G., Fairbanks, W. S., and Kauffman, M. J.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:Proceedings of the Royal Society of London Series B: Biological Sciences
Publisher:The Royal Society
ISSN (Online):1471-2954

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