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DEVELOPMENT OF A BIRD INTEGRITY INDEX: USING BIRD ASSEMBLAGES AS INDICATORS OF RIPARIAN CONDITION
Citation:
Bryce, S. A., R M. Hughes, AND P R. Kaufmann. DEVELOPMENT OF A BIRD INTEGRITY INDEX: USING BIRD ASSEMBLAGES AS INDICATORS OF RIPARIAN CONDITION. ENVIRONMENTAL MANAGEMENT. Springer-Verlag, New York, NY, 30(2):294-310, (2002).
Description:
We describe the development of a Bird Integrity Index (BII) that uses bird assemblage information to assess human impacts on 13 stream reaches in the Willamette Valley, Oregon. We used bird survey field data to test 62 candidate metrics representing aspects of bird taxonomic richness, tolerance or intolerance to human disturbance, dietary preferences, foraging techniques, and nesting strategies that were affected positively or negatively by human activities. Metrics were evaluated by plotting each one against a measure of site disturbance and eliminating unresponsive, highly correlated, or redundant measures. Ultimately 13 metrics were chosen for the index. Individual metric scores ranged continuously from 0 to 10, and index scores were weighted to range from 0 to 100. Scores were calibrated using historical species information to set expectations for the number of species expected under minimally disturbed conditions. Site scores varied from 82 for the least disturbed stream reach to 8.5 for an urban site. We compared the Bird Integrity Index site scores with other measures of biotic response developed during this study: a fish index of biointegrity (IBI) and two benthic macroinvertebrate metrics. The three assemblages agreed on the general level of disturbance; however, individual sites scored differently depending on specific indicator response to in-stream or riparian conditions.