Impacts of Urbanization on Spring Fish Communities

The upper San Antonio River is a highly modified stream within Edwards Plateau region of Central Texas, primarily because of cessation of spring flow, stream channelization, and discharges from waste water effluents.  As such, sections of the upper San Antonio River are targeted for stream rehabilitation.  Purposes of this study were to quantify level of degradation in the fish community by comparing historical and contemporary fish collections related to urbanization effects and quantify fish community metrics (e.g., richness, abundance) and fish-habitat associations among rehabilitated and non-rehabilitated sections.  Compared to non-urbanized and moderately modified spring fish communities, upper San Antonio River fish community represents a system with fewest spring fishes.  Habitat guides of fishes were more diverse in rehabilitated sections, as predicted.  Upper San Antonio River fish community, along with communities in other spring systems, can be used as a model to predict or measure levels of fish community degradation related to levels of stream modification and urbanization.