National Water-Quality Assessment (NAWQA) Project
Assess the status and trends of aquatic ecological conditions (invertebrates, fish, algae and habitat) in rivers and wadeable streams.
Relate ecological conditions to chemical stressors (such as nutrients and pesticides), physical disturbances (such as habitat and hydrologic alterations) in the context of different environmental settings and land uses.
Enhance understanding of factors that influence the biological integrity of streams and how these stream ecosystems may respond to diverse natural and human factors.
Develop key ecological indicators of aquatic health.
Daren M. Carlisle, Michael R. Meador, Stephen R. Moulton II, and Peter M. Ruhl
National Water-Quality Assessment Program, US Geological Survey, 413 National Center, 12201 Sunrise Valley Drive, Reston, Virginia 20192, U.S.A.
ABSTRACT.- Tolerance of macroinvertebrate
taxa to chemical and physical stressors are widely
used in the analysis and interpretation of bioassessment
data, but many estimates lack empirical bases. Our main objective was to
estimate genus- and family-level indicator values (IVs) from a data set of macroinvertebrate communities, chemical, and physical
stressors collected in a consistent manner throughout the