Environmental variables measured at multiple spatial scales exert uneven influence on fish assemblages of floodplain lak
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PRIMARY RESEARCH PAPER
Environmental variables measured at multiple spatial scales exert uneven influence on fish assemblages of floodplain lakes Daniel J. Dembkowski • L. E. Miranda
Received: 12 August 2012 / Revised: 25 July 2013 / Accepted: 4 August 2013 / Published online: 13 August 2013 Ó Springer Science+Business Media Dordrecht 2013
Abstract We examined the interaction between environmental variables measured at three different scales (i.e., landscape, lake, and in-lake) and fish assemblage descriptors across a range of over 50 floodplain lakes in the Mississippi Alluvial Valley of Mississippi and Arkansas. Our goal was to identify important local- and landscape-level determinants of fish assemblage structure. Relationships between fish assemblage structure and variables measured at broader scales (i.e., landscape-level and lake-level) were hypothesized to be stronger than relationships with variables measured at finer scales (i.e., in-lake variables). Results suggest that fish assemblage structure in floodplain lakes was influenced by variables operating on three different scales. However, and contrary to expectations, canonical correlations between in-lake environmental characteristics and fish assemblage structure were generally stronger than correlations between landscape-level and lake-level
Handling editor: Koen Martens D. J. Dembkowski (&) Department of Natural Resource Management, South Dakota State University, Box 2140B, Brookings, SD 57007, USA e-mail: [email protected] L. E. Miranda U.S. Geological Survey, Mississippi Cooperative Fish and Wildlife Research Unit, Box 9691, Mississippi State, MS 39762, USA
variables and fish assemblage structure, suggesting a hierarchy of influence. From a resource management perspective, our study suggests that landscape-level and lake-level variables may be manipulated for conservation or restoration purposes, and in-lake variables and fish assemblage structure may be used to monitor the success of such efforts. Keywords Fish assemblage structure CAP analysis Floodplain lake Mississippi Alluvial Valley Depth
Introduction Floodplain lakes created by the meandering of rivers are dynamic systems with unique and diverse habitats and environmental conditions (Baker et al., 1991; Sabo & Kelso, 1991). Thus, floodplain lakes are excellent systems for examining relationships between abiotic and biotic factors and fish assemblage structure. Floodplain lakes and other extra-channel habitats are important components of river–floodplain ecosystems in view of the fact that floodplain habitats support reproduction, growth, and recruitment of many channel-dwelling fishes (Welcomme, 1979; Penczak et al., 2003; Zeug et al., 2005; Nunn et al., 2007). Moreover, floodplain lakes support their own unique fish assemblages and species. Thus, there is a direct relationship between fish assemblage characteristics in floodplain habitats and fish assemblage characteristics in the
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main channel (Welcomme, 1979), and a river system’s gamma diversity. Recognit
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