Patterns of assemblage change in prairie stream fishes in relation to urban stormwater impoundments

Abstract

The effects of stream urbanization on fishes have been well studied in general. Yet despite the wealth of knowledge available for streams in many different ecoregions, relatively little is known of the effects of urbanization on prairie stream fishes. Management of urban stormwater through impoundment has the potential to fragment streams, and habitat fragmentation on nonurban streams has been documented to relate to declines in small-bodied mobile minnow species. We asked whether urban habitat fragmentation through stormwater impoundment would relate to a similar decline in small-bodied fishes in Cottonwood Creek, a stream system partially managed by stormwater impoundment in central Oklahoma. Analyses with basic metrics of ecological tolerance, richness, community structure, and multivariate ordination found negative relationships between cyprinid richness and abundance and a metric of urban habitat fragmentation, as well as between Lepomis humilis, a small-bodied sunfish, and the metric of urban habitat fragmentation. We review potential hypotheses for these biological patterns in fragmented urban streams, including predation, lack of successful reproduction, and lack of ability to recolonize above barriers.