HR: 15:30h
AN: NB24A-01    [Abstracts]
TI: A RIVPACS Type Model for Wadeable Streams of Wyoming
AU: * Hargett, E G
EM: eharge@state.wy.us
AF: Wyoming Department of Environmental Quality - Water Quality Division, Herschler Bldg. 4W, 122 W. 25th St., Cheyenne, WY 82002 United States
AU: Zumberge, J R
EM: jzumbe@state.wy.us
AF: Wyoming Department of Environmental Quality - Water Quality Division, 1866 S. Sheridan Ave., Sheridan, WY 82801 United States
AU: Hawkins, C P
EM: chuck.hawkins@usu.edu
AF: Department of Aquatic, Watershed and Earth Resources, Utah State University , 5210 Old Main Hill, Logan, UT 84322 United States
AB: RIVPACS models produce a community-level measure of biological condition known as O/E, which is derived from a comparison of the observed (O) biota with those expected (E) to occur in the absence of anthropogenic stress. Benthic macroinvertebrate and environmental data collected at 739 stream monitoring stations, from 1993 to 1999, were used to develop, validate, and apply a RIVPACS model to assess the biological condition of wadeable streams in Wyoming. We used multivariate analyses to group 157 reference sites based on similarities in macroinvertebrate community structure as well as examine which environmental variables best discriminated among reference groups. A suite of fifteen categorical and continuous environmental variables best discriminated among fifteen reference groups and explained >75% of the natural variability in biota within the reference dataset. Mean reference site O/E values were near unity. Mean test site values ranged from 0 to 1.60 (mean =0.79). Our model was accurate and reasonably precise (SD of O/E values for validation data = 0.17). O/E responded to anthropogenic stressors and was robust both temporally and spatially. These results show that RIVPACS models can produce effective assessments of biological condition over broad, ecologically diverse, geographic regions of the intermountain west such as Wyoming.
DE: 9350 North America
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly