Date of Award:
Master of Science (MS)
Mark C. McKinstry
Frank P. Howe
Stream fragmentation and non-native species introductions are among a suite of anthropogenic disturbances shaping the structure and function of freshwater ecosystems. The impacts of such alterations contribute to the global decline of stream fish biodiversity and may be synergistic in their effects. For example, the Colorado River basin’s unique native fish assemblage is imperiled not only by numerous dams and diversions, but also by threats of predation and competition for limited resources from non-native fish species. On the San Juan River, Utah, a recently formed fish barrier prevents upstream movement of native and non-native fish. The goal of this project is to weigh the relative benefit of excluding non-native species from the river upstream of the barrier versus the cost of also excluding native fish from their upstream populations. To accomplish this, we tested whether fish community metrics and species interactions differ between reaches above and below the waterfall to provide insight into how free movement of fishes may affect upstream native fish populations. Our results highlight the barrier shapes fish communities and limits potentially negative species interactions from propagating upstream.
Ahrens, Zachary T., "Fish Community Impacts and Conservation Implications of a Novel Barrier on the San Juan River, Utah" (2023). All Graduate Theses and Dissertations, Spring 1920 to Summer 2023. 8738.
Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .