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Document Type

Research

Keywords

Vertebrates, Community Ecology, Ecosystem Simplification, Coralville Reservoir in Iowa, Cone Marsh in Iowa

Abstract

The vertebrates in communities comprising a habitat with unpredictable water levels (the Coralville Reservoir) were compared to those present in communities comprising a habitat without severely fluctuating water levels (Cone Marsh). From data on the species of vertebrates and their relative abundance, it was determined that extensive ecosystem simplification had occurred in communities along the Coralville Reservoir. The major characteristics of this simplification were the following: 1) several species with similar modes of feeding were present at Cone Marsh but only species with generalized food habits were present along the Coralville Reservoir; 2) species at the top of food chains often were very rare or absent in communities along the Coralville Reservoir flood plain, and 3) food chains that were dominant at Cone Marsh often were less important on the Coralville Reservoir flood plain. On these characteristics is based the following hypothesis of ecosystem simplification: 1) a massive trophic simplification and reduction in the number of species present; 2) alterations in the trophic structure so that major food chains are different; 3) the replacement of specialized species by more generalized species capable of adapting to the environmental stresses imposed; and 4) severe reductions in, or elimination of, top trophic levels, which eliminates a mechanism for binding together communities in the same habitat.

Publication Date

September 1973

Journal Title

Proceedings of the Iowa Academy of Science

Volume

80

Issue

3

First Page

117

Last Page

128

Copyright

© Copyright 1973 by the Iowa Academy of Science, Inc.

Language

EN

File Format

application/pdf

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