We studied the effect of an engineered flow disturbance on macroinvertebrates in an intermittent N Texas stream. To augment a drinking water supply, water is being diverted through the natural stream channel. Quantitative sampling of sediments and woody debris was conducted immediately before water diversion, immediately after and periodically during recovery, for three diversion events over a 2-yr period. Reduction in total density of macroinvertebrates was dependent on type of substrate, averaging 76% in sediments as compared with 66% on woody debris. Recovery was rapid for most taxa, which often reached predisturbance density in less than 1 mo. For the entire macroinvertebrate assemblage in 1992 and chironomids only in 1991, resilience was greater on woody debris than on sediments. Compared with sand, the common inorganic substrate in this stream, woody debris was more stable, due in part to its retention by debris dams. It appears that woody debris is an important refuge and source of recolonizers to this sandy prairie stream after flow disturbances.
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The American Midland Naturalist
Vol. 139 • No. 2
April 1998
Vol. 139 • No. 2
April 1998