The Influence of Channelization on Fish Communities in an Agricultural Coldwater Stream System

We characterized coldwater stream fish community response to habitat degradation and channelization for agriculture. Coldwater streams are not common in the lower midwestern United States, and these streams differ from warmwater streams with respect to their diversity and community response to degradation. Six sites were sampled on the coldwater Mac-o-chee Creek in Ohio. Three reaches were classified as geomorphically constrained (by a roadway) and three as recovering (unconstrained and not channelized or cleaned for more than 100 y). Within each reach 31 mesohabitat units were sampled and were delineated as riffles, runs, or pools. Our goals were: (1) to examine how habitat and geomorphic impairment influences the abundance and community structure of coldwater fishes; and (2) to test whether the constraints on recovery from channelization were more influential in structuring communities than mesohabitat types. Our hypothesis was that we would find lower species diversity overall in the recoverin...