HR: 11:15h
AN: NB32C-04 INVITED     [Abstracts]
TI: Site Classes, Reference Conditions, and Multimetric Indexes for Mississippi Wadeable Streams
AU: * Stribling, J B
EM: james.stribling@tetratech.com
AF: Tetra Tech, Inc., 400 Red Brook Blvd., Suite 200, Owings Mills, MD 21117-5159 United States
AU: Bressler, D W
EM: david.bressler@tetratech.com
AF: Tetra Tech, Inc., 400 Red Brook Blvd., Suite 200, Owings Mills, MD 21117-5159 United States
AU: Hicks, M B
EM: caddisman88@hotmail.com
AF: Mississippi Department of Environmental Quality, 2380 Highway 80 West, Jackson, MS 39204 United States
AU: Reed, R
EM: randy_reed@deq.state.ms.us
AF: Mississippi Department of Environmental Quality, 2380 Highway 80 West, Jackson, MS 39204 United States
AU: Beiser, M
EM: mike_beiser@deq.state.ms.us
AF: Mississippi Department of Environmental Quality, 2380 Highway 80 West, Jackson, MS 39204 United States
AB: In December 2000, Mississippi initiated a project to develop reference conditions for quantitative biological evaluation of the impairment status of its wadeable streams. Five hundred thirty-five (535) samples were collected from 475 sites and included field chemistry, laboratory analytical chemistry, physical habitat quality assessment (including particle size distribution), and benthic macroinvertebrates. Physical and chemical criteria were used to define sites as reference, subreference, and stressor sites; Bray-Curtis similarity coefficients and non-metric multidimensional scaling (NMDS) were used to group reference and subreference sites into five site classes, or bioregions. A suite of 82 metrics was calculated for all samples and tested for their capacity to detect stressor conditions; a final set of 20 metrics distributed among the five bioregions (6-7 per site class) was identified. Four alternate metric suites per bioregion were tested for discrimination efficiency (DE), and a single index (Mississippi-Benthic Index of Stream Quality [M-BISQ]) selected for each. The five separate multimetric indexes have an overall coefficient of variation of 10.6%, a 90% confidence interval of ±10 points on a 100-point scale, and a mean DE of 91.8%. The 25^th percentile of the reference site M-BISQ distribution for each site class is specified as the impairment/nonimpairment threshold.
DE: 1803 Anthropogenic effects
DE: 1806 Chemistry of fresh water
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
DE: 1871 Surface water quality
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly