Fish Assemblage Associations with Floodplain Connectivity Following Restoration to Benefit an Endangered Catostomid

Abstract

The dynamics of stream and floodplain connectivity are a growing consideration for restoration projects. Restoration of a tributary stream to Utah Lake was undertaken in 2008 with the intent of increasing available spawning and nursery habitat for the endangered June Sucker Chasmistes liorus. Restoration efforts provided an opportunity to evaluate relationships between fish assemblages and variables related to the physiochemical environment, vegetation, and habitat connectivity at floodplain ponds. Fish were collected with beach seines and habitat variables were measured each month at 12 floodplain ponds during March 2010 to March 2011. Total catch was predominated by nonnative species: Green Sunfish Lepomis cyanellus, Western Mosquitofish Gambusia affinis, Black Bullhead Ameiurus melas, Fathead Minnow Pimephales promelas, and Bluegill Lepomis macrochirus. Both indirect and direct gradient analyses indicated a significant correlation between fish assemblages and site connectivity. The percentage and type of macrophyte cover (e.g., emergent, submergent) also played a significant role in structuring fish assemblages. Species richness was generally higher at sites with intermediate to high connectivity than at sites with lower connectivity. Sites with lower connectivity were predominated by Green Sunfish, Mosquitofish, and Fathead Minnow. June Suckers were collected from sites with intermediate values of connectivity and vegetation. Observed patterns suggested connectivity structured initial fish assemblages and macrophyte colonization dynamics; subsequent interactions between local habitat (i.e., percent vegetation) and biotic factors (e.g., competition, predation, etc.) provided site-specific interactions and structure. The results of this study indicate connectivity dynamics should be an important consideration in stream and floodplain restoration efforts.

Received March 1, 2015; accepted September 30, 2015

ACKNOWLEDGMENTS

I am grateful for the extensive field assistance of David Tinsley, Mark Grover, and Jackie Watson. I also thank Mark Grover for comments provided during the development of this manuscript, as well as a helpful review. I give many thanks to numerous Utah Division of Wildlife Resources personnel for field assistance. The June Sucker Recovery Implementation Program provided financial support for this project. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the author, the U.S. Department of Agriculture, or the Utah Division of Wildlife Resources.