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The Effect of Predation Risk on Elk Populations

NSF Award:

Behavioral Responses of Elk to Wolves: Proximate Triggers, Response Strategies, Physiological Costs and Demographic Consequences.  (Montana State University)

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Scott Creel of Montana State University and his research team are studying the behavior of elk in response to the risk of predation by wolves. They are assessing the physiological costs of these responses, and their impact on elk reproduction, survival and population growth. Their study is one of the first to test the hypothesis that risk effects of predation are important to the way that predators structure ecosystems. Risk effects are the high costs prey face when they must alter their behavior in response to predators.

The research team has discovered that when wolves are present, elk alter their behavior by increasing vigilance while decreasing foraging, and changing their habitat preference by favoring wooded habitats. Elk have changed their grouping patterns by decreasing herd size and become more sensitive to environmental conditions. The reproductive rates of elk populations were inversely related to the local intensity of wolf predation. Elk in locations with relatively high numbers of wolves produced fewer young, so that elk populations with high wolf-to-elk ratios declined, while those with fewer wolves were growing.

The team has recently expanded their research to measure direct predation rates and behavioral responses to predation risk for prey of lions and spotted hyenas in the southern Rift Valley of Kenya. Understanding predator-prey dynamics in these populations is crucial to wildlife management and conservation efforts.

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  • Photo of elk
Elk will change their habitat preference, alter reproductive rates and decrease foraging in the presence of large wolf populations.
2010 Jupiterimages Corporation
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