Effects of channel incision on base flow stream habitats and fishes |
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Authors: | F D Shields Jr S S Knight C M Cooper |
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Institution: | (1) US Department of Agriculture Agricultural Research Service, National Sedimentation Laboratory, P.O. Box 1157, 38655-1157 Oxford, Mississippi, USA |
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Abstract: | Channel incision is a widespread phenomenon that results in stream and riparian habitat degradation. Fishes and physical habitat
variables were sampled at base flow from three incised stream channels and one reference stream in northwest Mississippi,
USA, to quantify incision effects on fish habitat and provide a basis for habitat rehabilitation planning and design. Incised
channels were sampled in spring and autumn; the reference channel was sampled only in the autumn. Incised channel habitat
quality was inferior to the reference channel despite the presence of structures designed to restore channel stability. Incised
channels had physical habitat diversity levels similar to a nonincised reference channel, but contained fewer types of habitat.
At base flow, incised channels were dominated by shallow, sandy habitats, moderate to high mean local Froude numbers, and
had relatively little organic debris in their beds. In contrast, the reference stream had greater mean water depth, contained
more woody debris, and provided more deep pool habitat. Fish assemblages in incised channels were composed of smaller fishes
representing fewer species relative to the reference site. Fish species richness was directly proportional to the mean local
Froude number, an indicator of the availability of pool habitat. |
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Keywords: | Streams Erosion Sediment Woody debris Channel degradation Habitat restoration Fish Diversity indices |
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