The role of fish predation and spatial heterogeneity in determining benthic community structure.

Abstract

Bluegill sunfish Lepomis macrochirus predation had a significant impact on both the number of benthic species and the densities of certain benthic macroinvertebrate groups. The predatory chironomid Clinotanypus pinguis showed a strong negative response to bluegill predation, with fish exclusion resulting in higher densities throughout the year. A group of herbivorous chironomids exhibited a response to fish predation that varied over the year, with predation resulting in elevated densities in the fall and winter but reduced densities in the summer. Many of the other species found in the littoral zone showed no significant response to bluegill predation. In addition, fish predation had no significant effect on densities of most macroinvertebrates occurring on the macrophytes. These complex responses of the various macroinvertebrates to fish predation are explainable in terms of seasonal changes in predation intensity and the importance of invertebrates vs. vertebrate predation.-from Author