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Tuesday, May 27, 2008
200
Changes in the biological community of the Taylor River below Taylor Park Reservoir (Gunnison County, CO, U.S.A.) between 1989 and 2006
Kevin D. Alexander, Department of Natural and Environmental Sciences, Western State College of Colorado, Hurst Hall, Gunnison, CO 81231 and Tim Lapello, Bio-Environs, 114 N. Boulevard St., Suite 202, Gunnison, CO 81230.
In 2006, we inventoried and assessed the aquatic biological community in the Taylor River (Gunnison County, CO, U.S.A.) at three sites downstream from Taylor Park Dam and compared the results to those reported in 1989. We collected data on the physical conditions, habitat conditions, salmonid abundance, aquatic macroinvertebrates and periphyton during October and November, 2006. Our results show a loss in early age classes of salmonids, a decline of macroinvertebrate density of approximately 30% to 50% depending on site, a change in dominant macorinvertebrate taxa, but no major change in total macroinvertebrate diversity. Dominant periphyton taxa also dramatically changed and the periphyton community is now dominated by species that are less tolerant to fluctuating stream flows. These changes may be explained by a reduction in winter flows through Taylor Park Dam and the possible reduction in entrained Mysis relicta due to a change in the management of reservoir levels designed to reduce the density and vertical diel migrations of M. relicta in Taylor Park Reservoir.
Web Page: macroinvertebrates, salmonids, assessment
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See more of The Nabs 56th Annual Meeting (25-28 May, 2008)