HR: 1330h
AN: B33E-03    [Abstracts]
TI: Hydrogeomorphic Classification of Benthic Macroinvertebrate Assemblages in the Pacific Northwest Mountains
AU: * Cuhaciyan, C O
EM: fluvial@engr.colostate.edu
AF: Department of Civil Engineering, Colorado State University, 1320 Campus Delivery Engineering Research Center, Fort Collins, Co 80523 United States
AU: Bledsoe, B P
EM: bbledsoe@engr.colostate.edu
AF: Department of Civil Engineering, Colorado State University, 1320 Campus Delivery Engineering Research Center, Fort Collins, Co 80523 United States
AU: Olden, J D
EM: olden@wisc.edu
AF: Center for Limnology, University of Wisconsin, Madison, WI 53706, Madison, WI 53706 United States
AU: Poff, N L
EM: poff@lamar.colostate.edu
AF: Department of Biology, Colorado State University, Fort Collins, CO 80523, Fort Collins, CO 80523 United States
AB: Existing physical classifications for streams do not explicitly include considerations of how primary environmental drivers such as flow regime, geophysical setting, intermediate-scale geomorphic processes, and anthropogenic impacts vary in importance across spatial scales in structuring biotic communities. We present a multi-scale hydrogeomorphic classification of 307 sites in 6 mountainous ecoregions of the Pacific Northwest. Innovative descriptors of flow regime, geophysical setting, valley geomorphology, and substrate are used to construct both a priori and a posteriori hydrogeomorphic classifications. Clusters based on benthic macroinvertebrate data from R/EMAP sites provide a neutral-model classification representing the best achievable classification of benthic invertebrate assemblages and the basis for a posteriori classification. Given the emphasis on geographically-dependent classifications in bioassessments, we also group sites by ecoregion. The relative strengths of the four classification schemes are assessed by the extent to which average within-class assemblage similarities exceed the average similarity between classes based on the Sorensen-Dice (presence / absence) similarity measure. A better understanding of the key hydrogeomorphic processes that filter benthic macroinvertebrate communities provides a process-based framework for interpreting biomonitoring information from diverse watershed contexts and systematically selecting reference streams that are similar with regard to the most relevant physical drivers within a region.
DE: 0400 Biogeosciences
DE: 1824 Geomorphology (1625)
SC: Biogeosciences [B]
MN: 2005 Joint Assembly