The Importance of Large Carnivores to Healthy Ecosystems

Brian Miller
Denver Zoological Foundation, 2900 E. 23rd Avenue, Denver CO 80205; (303) 376-4944;
zooconservation@denverzoo.org

Barb Dugelby
The Wildlands Project, PO Box 455, Richmond VT 05477

Dave Foreman
The Wildlands Project, PO Box 455, Richmond VT 05477

Carlos Martinez del Río
Department of Zoology, University of Wyoming, Laramie WY 82071

Reed Noss
Conservation Science, Inc., 7310 NW Acorn Ridge, Corvallis, OR 97330

Mike Phillips
Turner Endangered Species Fund, 1123 Research Drive, Bozeman, MT 59718

Rich Reading
Denver Zoological Foundation, 2900 E. 23rd Avenue, Denver CO 80205

Michael E. Soulé
The Wildlands Project, PO Box 455, Richmond VT 05477

John Terborgh
Center for Tropical Conservation, Box 90381, Duke University, Durham NC 27708

Louisa Willcox
Sierra Club, 97 Suce Cr. Road, Livingston MT 59047

Abstract

Land managers often are responsible for the maintenance of species diversity and resilience.

This requires knowledge of ecosystem dynamics over decades and centuries. Resource-driven

(bottom-up) models have guided early thought on managing species and ecosystems. Under this

paradigm, carnivores have little ecological value, and throughout the 20th Century carnivore

management strategies (often extirpation) have reflected that concept. An alternative hypothesis,

however, states that herbivores reduce the biomass of plants, but in turn, the biomass of herbivores

is checked by the presence of carnivores. As such, carnivores have great ecological value.

Their predation activities create impacts that ripple downward through the trophic levels of an

ecosystem. Here we discuss some potential pathways through which carnivores contribute to

ecosystem processes and species diversity. The subtleties of these interactions have strong implications

for management strategies of carnivores. Without considering these indirect impacts,

short-sighted management strategies to reduce carnivores might cause extensive and long-term

changes in ecosystem structure and function.