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Effects of two classification strategies on a Benthic Community Index for streams in the Northern Lakes and Forests Ecoregion

Jason T. Butcher·Paul M. Stewart·Thomas P. Simon
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Abstract

Ninety-four sites were used to analyze the effects of two different classification strategies on the Benthic Community Index (BCI). The first, a priori classification, reflected the wetland status of the streams; the second, a posteriori classification, used a bio-environmental analysis to select classification variables. Both classifications were examined by measuring classification strength and testing differences in metric values with respect to group membership. The a priori (wetland) classification strength (83.3%) was greater than the a posteriori (bio-environmental) classification strength (76.8%). Both classifications found one metric that had significant differences between groups. The original index was modified to reflect the wetland classification by re-calibrating the scoring criteria for percent Crustacea and Mollusca. A proposed refinement to the original Benthic Community Index is suggested. This study shows the importance of using hypothesis-driven classifications, as well as exploratory statistical analysis, to evaluate alternative ways to reveal environmental variability in biological assessment tools.

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Jason T. Butcher, Paul M. Stewart, Thomas P. Simon. 2003. Effects of two classification strategies on a Benthic Community Index for streams in the Northern Lakes and Forests Ecoregion. https://doi.org/10.1016/s1470-160x(03)00043-8

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