Document Type


Publication Title

Journal of the North American Benthological Society


The University of Chicago Press

Publication Date


Publisher location

Chicago, IL

First Page


Last Page


Issue Number


Volume Number


Abstract/ Summary

Many state water-quality agencies use biological assessment methods based on lotic fish and macroinvertebrate communities, but relatively few states have incorporated algal multimetric indices into monitoring programs. Algae are good indicators for monitoring water quality because they are sensitive to many environmental stressors. We evaluated benthic algal community attributes along a landuse gradient affecting wadeable streams and rivers in Maine, USA, to identify potential bioassessment metrics. We collected epilithic algal samples from 193 locations across the state. We computed weighted-average optima for common taxa for total P, total N, specific conductance, % impervious cover, and % developed watershed, which included all land use that is no longer forest or wetland. We assigned Maine stream tolerance values and categories (sensitive, intermediate, tolerant) to taxa based on their optima and responses to watershed disturbance. We evaluated performance of algal community metrics used in multimetric indices from other regions and novel metrics based on Maine data. Metrics specific to Maine data, such as the relative richness of species characterized as being sensitive in Maine, were more correlated with % developed watershed than most metrics used in other regions. Few community-structure attributes (e.g., species richness) were useful metrics in Maine. Performance of algal bioassessment models would be improved if metrics were evaluated with attributes of local data before inclusion in multimetric indices or statistical models.

Citation/Publisher Attribution

Danielson, T.J., Loftin, C.S., Tsomides, L., DiFranco, J.L., & Connors, B. 2011. Algal bioassessment metrics for wadeable streams and rivers of Maine, USA. J. North American Benthological Society 30:1033-1048.

Publisher Statement

© 2011 Society for Freshwater Science


DOI: 10.1899/10-162.1


publisher's version of the published document