Taxonomic resolution of benthic macroinvertebrate communities in bioassessments

BRIDGES is a recurring feature of J-NABS intended to provide a forum for the interchange of ideas and information between basic and applied researchers in benthic science. Articles in this series focus on topical research areas and linkages between basic and applied aspects of research, monitoring, policy, and education. Readers with ideas for topics should contact Associate Editors, Nick Aumen and Marty Gurtz.The issue of taxonomic resolution has been a topic of interest in benthological studies for a long time, but the increasing use of aquatic insects—and more recently algae—in assessing water quality has heightened the importance of understanding the tradeoffs associated with different levels of taxonomy. Bailey and co-authors lead off this set of papers with a review of the types of studies and questions for which species identifications are essential, but then examine whether there are circumstances—e.g., in some bioassessments—in which taxonomic information at a higher (e.g., family) level is sufficient, or may even be better. They propose a 2-tiered approach for taxonomy used in bioassessment studies: family-level identifications for multivariate analyses or index calculation, and species identification for a short list of indicator taxa that are appropriate for a particular study. Lenat and Resh review a variety of uses of taxonomic information for aquatic insects and recommend levels of taxonomy that are appropriate for different situations. They conclude that biological monitoring studies yield the greatest benefits using genus- or species-level taxonomy. Hill et al. examine issues of taxonomic resolution for diatom studies, using results from a large set of diatom assemblage data collected from 199 streams over a 3-y period. They found that genus-level taxonomy appears to adequately describe the response of some diatom assemblage attributes to environmental gradients, especially for those gradients that involve morphological (motility) or physiological (pH tolerance) adaptations that are related to evolved genus-level characteristics.Nick Aumen, [email protected]Marty Gurtz, [email protected]Co-editors