Responses in Fish Community Structure to Restoration of Two Indiana Streams

Abstract

Stream restoration has accelerated in the Midwestern United States during the past decade, but the effects of restoration on stream biota are rarely evaluated. From 1997 to 2000, we studied the responses in fish communities to the attempted restoration of two channelized streams (Juday Creek and Potato Creek) in northwestern Indiana, each of which received two new meanders to a 1-km reach of stream length. The restored meanders of Juday Creek also received major improvement to instream habitat, bank stabilization, and silt control. In contrast, Potato Creek received only reconnection of the stream to historical meanders. Fish were monitored for 3 years after reconstruction by use of electroshocking and salmonid redd surveys. In Juday Creek, trout size-class distribution broadened and redd construction increased in the restored reaches. However, most fish metrics for reconstructed reaches did not surpass the levels in the channelized reaches after 3 years. Continued sedimentation from upstream sources, which reduced habitat quality, likely counteracted the positive effects of the restoration. In contrast, unanticipated geomorphic changes in Potato Creek led to decreased current velocity and highly altered fish community structure. The American brook lamprey Lampetra appendix, a sensitive species, was not collected after restoration, and the fish community changed from rheophilic species to highly tolerant, slow-water species. Overall, changes in fish community structure revealed strengths and weaknesses in contemporary stream restoration approaches, findings that will aid future restoration efforts.