HR: 08:45h
AN: NB31E-02    [Abstracts]
TI: A rapid bioassessment of stream diversion effects
AU: * Pepin, D M
EM: dpepin@lamar.colostate.edu
AF: Colorado State University, Department of Biology, Fort Collins, CO 80523-1878 United States
AU: Albano, C M
EM: calbano@lamar.colostate.edu
AF: Colorado State University, Department of Biology, Fort Collins, CO 80523-1878 United States
AU: Poff, N L
EM: poff@lamar.colostate.edu
AF: Colorado State University, Department of Biology, Fort Collins, CO 80523-1878 United States
AB: Ecologists recognize that flow alterations imposed by dams impair water quality and many ecosystem processes. However, there is little empirical evidence addressing the ecological effects of stream dewatering through flow diversion. Intensive, multi-year sampling of macroinvertebrates and periphyton from streams in a single subalpine basin in Colorado has shown reduced abundance and diversity of macroinvertebrates and increased periphyton production in diverted reaches. This research suggests that ecosystem structure and function can be affected by diversion-mediated environmental changes. Our rapid bioassessment investigated the generality of the macroinvertebrate response to diversion. Following established EPA methods, we sampled 15 diverted streams across a range of watershed areas and diversion operation categories throughout Colorado and southern Wyoming over 4 days in September, 2004. Scoring of habitat variables demonstrated that diversion severely reduced habitat quality at all sites, compared to upstream reference sites, irrespective of the operational category of diversion. Macroinvertebrate abundance, richness, and evenness were reduced in poor-condition habitats. These results suggest that diversions of all types have the potential to depress basal food web members and thus likely diminish production of higher trophic levels in both the stream and adjacent riparian zone.
DE: 1803 Anthropogenic effects
DE: 9901 NABS Student Award - Basic Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly