Algal bioassessment metrics for wadeable streams and rivers of Maine, USA

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

TB208: Biological Water Quality Standards to Achieve Biological Condition Goals in Maine Rivers and Streams: Science and Policy

This publication describes the philosophy, history, methodology, and management applications of numeric biological criteria in water quality standards in Maine. The presentation describes the decision-making process used by the Maine Department of Environmental Protection (MDEP) for assessing attainment of aquatic life uses in water quality standards using benthic macroinvertebrates in Maine streams and rivers including eight case studies of management applications and the improved environmental outcomes that have resulted. The MDEP, University of Maine, and business and nonprofit stakeholders participated in the development and testing of Maine’s numeric biological criteria. This publication further discusses the broader relevance of numeric biological criteria in water quality management at both the state and federal levels and considers parallels and differences between Maine’s biological criteria and other biological assessment methods in the United States and the European Union.https://digitalcommons.library.umaine.edu/aes_techbulletin/1205/thumbnail.jp