Fish Responses to Alterations of a Transition Zone Stream

Borders of eco-regions contain blended habitats that share characteristics and ecological processes from the adjacent landscapes.  The transition zone between the Great Plains and the Rocky Mountains (The Front Range) contains ecosystems similar to the plains but at higher elevations, which creates habitat for both cold and warm water fishes. These regions are not only accommodating to diverse fish and wildlife communities; they are also appealing to humans.  To satisfy the growing population, development of these aquatic systems was two-fold: 1) Dams and diversions were built to supply water to Front Range communities and 2) nonnative sport-fish were stocked to benefit fishermen. The North Fork Cache la Poudre River has been developed for water resources since the 1900s and both reservoirs on it have been slated for expansion.  However, current management strategies seek to balance water needs with a functional native fish assemblage.  I designed a field study to investigate the fish community responses to anthropogenic modifications.  Extirpation of native fishes including common shiner (Luxilus cornutus) and bigmouth shiner (Notropis dorsalis) appear to have occurred along with an overall increase in species richness since the first sampling efforts in 1959. Mechanisms behind these changes and management implications are then explored.