Cheek, B.D. & T.B. Grabowski. 2014. Evaluating habitat associations of a fish assemblage at multiple scales in a minimally disturbed stream on the Edwards Plateau, central Texas. U.S. Department of Interior, Fish and Wildlife Service, Cooperator Science Series FWS/CSS-104-2014, Washington, D.C.
Understanding the influence that different spatial scales within a watershed have on instream habitat is essential for accurately quantifying fish habitat associations and developing effective means for assessing stream conservation and restoration activities. In this study, we used a combination of side scan sonar surveys, imagery collected by unmanned aerial vehicle, and fish collection to evaluate the effect of physicochemical and landscape variables at various spatial scales, e.g., micro-mesohabitat, mesohabitat, riffle-run-pool complex, stream reach, on the stream fish assemblage habitat associations in the South Llano River, a spring-fed second order stream on the Edwards Plateau in central Texas. We found that the mice-mesohabitat scale and the riffle-run-pool complex scale had the greatest explanatory power. Many of the fishes endemic to the streams of the Edwards Plateau, such a Guadalupe bass Micropterus treculii and Texas logperch Percina carbonaria, exhibited associations with similar physicochemical and landscape variables. Our results suggest that conservation and restoration efforts targeting single species, such as the Guadalupe Bass Initiative, can benefit a suite of species. However, our results did not demonstrate incontrovertibly that a single species, such as Guadalupe bass, can serve as an indicator of the status of the stream fish assemblage as a whole. These findings will help provide data on the habitat use patterns of a fish assemblage in a relatively undisturbed Edwards Plateau stream and potentially help prioritize future restoration efforts for other streams in the region.