Relation of Floodplain Lake Fish Communities and River Connectivity in the Lower White River, Arkansas PDF Download

Author: Sandra J.. Clark
Publisher:
ISBN:
Category : Fish communities
Languages : en
Pages : 324

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Book Description
Abstract: Floodplain lakes have been extensively studied in tropical systems, but little is known about the influence of connectivity on floodplain lake fish communities in temperate systems. Relationships between floodplain lake connectivity and fish community dynamics within the White River National Wildlife Refuge, Arkansas were investigated and temporal patterns of fish communities were characterized. In 2002,2004, and 2005, a total of 41 floodplain lakes were sampled using various combinations of gears including: boat electrofishing, experimental gill nets, mini-fyke nets, and large-mesh gill nets. Environmental variables including water quality, lake morphometrics, and quantitative measures of connectivity were measured for each lake. Canonical correspondence analysis identified temperature, lake shape, type of connection, and start date of connection as most important in the structuring of floodplain lake fish communities. Three floodplain lake classification types were generated with large, deep, long, and narrow lakes with great temporal connection via a slough or bayou having greater abundances of rheophilic species. Intermediate size, shape, depth, and connectivity lakes were associated with rheophilic and more lacustrine species; while small, shallow, round lakes with low temporal connection due to overbank connection were associated with more lacustrine species. Five floodplain lakes followed over the entire 4-year period (2002,2004, and 2005) demonstrated a shift from cyprinid to cyprinid/centrarchid dominated systems; however, no temporal changes in richness or diversity were found. Previous year's connectivity may have influenced dominance shifts more rheophilic species toward more lacustrine species in subsequent years as connectivity conditions changed. Eight floodplain lakes were sampled during periods of documented with some lakes becoming completely inundated during high stage conditions while others were only connected via a ditch. During connection, lakes with complete inundation had lower catch per unit effort and diversity than lakes with ditch connection. It seems likely that fish dispersed from inundated lakes into the floodplain for spawning. Additionally, measured spatial and temporal connection gradients appeared to influence fish communities in floodplain lakes during periods of connection and disconnection. Connectivity is more important in influencing floodplain lake fish communities than previously documented.