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Productivity, Consumers, and the Structure of a River Food Chain
J. Timothy Wootton and Mary E. Power
Proceedings of the National Academy of Sciences of the United States of America
Vol. 90, No. 4 (Feb. 15, 1993), pp. 1384-1387
Published by: National Academy of Sciences
Stable URL: http://www.jstor.org/stable/2361194
Page Count: 4
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We tested models of food chain dynamics in experimentally manipulated channels within a natural river. As light levels increased, primary productivity and the biomass of algae and primary predators increased, but the biomass of grazers remained relatively constant. In the presence of a fourth trophic level, algae and primary predators decreased, but grazers increased. These results match predictions of food chain models based on classical predator-prey theory and suggest that simple models of multitrophic level interactions are sometimes sufficient to predict the responses of natural communities to changes in environmental productivity and predators.
Proceedings of the National Academy of Sciences of the United States of America © 1993 National Academy of Sciences