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Grand Teton National Park Report

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The abundance and diversity of mammals will be greatly affected by a number of factors, including plant productivity, climate, natural disturbance, and disease. Of particular interest to conservation strategies, there is little known about the ecological role that carnivores play in maintaining ecosystem structure. Large carnivores were essentially eliminated from much of their range during the last century. Yet, a growing body of experimental evidence indicates that top carnivores are keystone species, and they play important roles in maintaining the health of Nature. The predatory activities of large carnivores produce effects that ripple through the trophic levels of an ecosystem and affect organisms that seem distantly removed, ecologically and taxonomically. But, few studies have examined the indirect impacts of predation across those trophic levels. Such studies have been deemed a high priority in the Greater Yellowstone Ecosystem. Presently, we are assessing the abundance of selected species of mammals at sites representing five major vegetation types found in the Grand Teton National Park. The five vegetation sites are sampled in areas with and without wolves. The size range of these mammals extends from voles/mice to coyotes. Small rodents are being assessed through standard capture/recapture techniques using Sherman traps. Carnivores are being estimated by genetic identification of scat. That method is non-invasive, and by walking transects two times, we can essentially estimate populations sizes using the Lincoln-Peterson statistical technique. Mammals that can not be easily trapped or identified through scat will be followed over time using indices of abundance.