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TOWARDS AN INDEX OF AQUATIC VERTEBRATE ASSEMBLAGE INTEGRITY FOR STREAMS AND RIVERS IN OREGON AND WASHINGTON
Citation:
Lomnicky, G. A., R M. Hughes, AND P L. Ringold. TOWARDS AN INDEX OF AQUATIC VERTEBRATE ASSEMBLAGE INTEGRITY FOR STREAMS AND RIVERS IN OREGON AND WASHINGTON. Presented at Oregon Chapter of American Fisheries Society, Sunriver, OR, February 27-March 1, 2002.
Description:
This research expands upon earlier Indices of Biotic Integrity (IBI) efforts that have been developed for the Northwest including the Willamette Valley IBI and the Coast Range coldwater IBI. This Oregon/Washington IBI presently being developed encompasses a broader geographic scale, diversity of landscapes (e.g., mountains, plains, deserts, temperate rainforest, etc.) and stream size than previous IBI's, which presents considerable challenges to developing indicators of assemblage and stream condition. We have combined data from federal, state and university sources representing 545 site visits with 343 unique sites, towards developing an indice of aquatic vertebrate assemblage integrity for streams and rivers of Oregon and Washington. All sources used a common protocol. A preliminary set of metrics have been identified including percent coldwater species, percent sensitive individuals, number of native fish species, number of native anadromous species, number of tolerant species, percent nonnative individuals, percent amphibian individuals, and number of benthic species at each site. These 8 AVA metrics were selected from an initial set of 113 metrics. Retained metrics passed a range test ( r > 2), responded to indicators of human disturbance gradients at watershed and reach specific scales, passed redundancy checks (r<0.75), and had signal to noise ratios >3. The IBI metrics will be calibrated using 75% of the data set then tested using the remaining portion of the data set. The final product will be an assessment of all sites for AVA integrity by using the index to score each of the sites.