Effects of small impoundments on the fish assemblages in low-order streams.

摘要

Impoundments have been constructed across a wide range of stream orders. I sought to identify the effect that impoundments in low-order streams have on the fish assemblages. I examined how fish assemblages, instream habitat, and water quality conditions differed among sites above and below impoundments and among sites in unimpounded streams.; Four impounded and three unimpounded streams were sampled for this study. Impoundments affected upstream and downstream fish assemblages. The loss of community connectivity influenced the fish assemblages in stream sites above impoundments. Short distances downstream from impoundments, fish assemblages were affected by alterations to instream habitat conditions. Alterations to water quality conditions below impoundments were not severe enough to impact fish assemblages. The downstream impacts of impoundments were restricted to sections of streams immediately below the impoundments. At a site farther downstream, the impact of the impoundments on environmental conditions were minimal.