Comparison of fish assemblages in two disjoined segments of an oxbow lake in relation to connectivity

Transactions of the American Fisheries Society
By:  and 

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Abstract

Disconnection between adjacent habitat patches is one of the most notable factors contributing to the decreased biotic integrity of global ecosystems. Connectivity is especially threatened in river–floodplain ecosystems in which channel modifications have disrupted the lateral links between the main river channel and floodplain lakes. In this study, we examined the interaction between the interconnectedness of floodplain lakes and main river channels and fish assemblage descriptors. Fish assemblages in two segments of an oxbow lake, one connected to and the other isolated from the Yazoo River, Mississippi, were estimated with daytime boat electrofishing during 2007–2010. The frequency of connection for the connected segment ranged from zero to seven individual events per year (mean, ∼2). The timing of most connection events reflected regional precipitation patterns. Greater species richness, diversity, and evenness were observed in the connected segment. Additionally, the connected segment had a greater abundance of piscivores and periodic life history strategists. All fishes collected solely in the connected segment were typically riverine in nature, whereas fishes collected only in the disconnected segment were more lacustrine adapted. These results suggest that periodic connection and the associated habitat heterogeneity that it provides are important for maintaining fish species richness and diversity in large-river floodplain lakes. We suggest that maintenance or restoration of connection be an integral part of fluvial ecosystem management plans.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Comparison of fish assemblages in two disjoined segments of an oxbow lake in relation to connectivity
Series title Transactions of the American Fisheries Society
DOI 10.1080/00028487.2011.607044
Volume 140
Issue 4
Year Published 2011
Language English
Publisher Taylor & Francis
Contributing office(s) Coop Res Unit Atlanta
Description 10 p.
First page 1060
Last page 1069
Country United States
State Mississippi
Other Geospatial Hard Cash Lake
Online Only (Y/N) N
Additional Online Files (Y/N) N