HR: 1330h
AN: B33E-05    [Abstracts]
TI: Conditional Probability Approach for Assessing Fine Sediment Impacts on Aquatic Insects
AU: * Hurst, B E
EM: behurst@engr.colostate.edu
AF: Department of Civil Engineering, Colorado State University, Fort Collins, CO 80523
AU: Bledsoe, B P
EM: bbledsoe@engr.colostate.edu
AF: Department of Civil Engineering, Colorado State University, Fort Collins, CO 80523
AU: Poff, N L
EM: poff@lamar.colostate.edu
AF: Department of Biology, Colorado State University, Fort Collins, CO 80523
AU: Albano, C M
EM: calbano@lamar.colostate.edu
AF: Department of Biology, Colorado State University, Fort Collins, CO 80523
AB: We examine the response of benthic macroinvertebrates to deposited fine sediments using R/EMAP sites from the Southern Rockies Ecoregion of Colorado and data from a field experiment conducted in a gravel-bed mountain stream in Southern Wyoming in autumn 2004. A conditional probability approach based on selected benthic macroinvertebrate indices (EPT richness and others) is employed to express the likelihood of a reduced number of sensitive taxa given an exceedance of reach-scale percent sand and fines (less than or equal to 2mm), and deviation from regional mean levels of deposited fine sediments by stream type. We address natural variability in fine sediment resulting from differences in hydrogeomorphic context by stratifying R/EMAP sites according to relevant watershed-, valley-, and local-scale variables. This research demonstrates a transferable approach for 1) assessing the risk of impacts to stream biota associated with fine sediment deposition in various regional contexts, and 2) improving interpretation of qualitative sediment deposition standards.
DE: 0400 Biogeosciences
DE: 1871 Surface water quality
SC: Biogeosciences [B]
MN: 2005 Joint Assembly