BIOASSESSMENT INFORMATION

Bioassessments using benthic invertebrate communities in freshwater habitats has received a great deal of recent attention. Advantages to this approach, include:

Being a direct or definitive measure of biotic integrity.....not an indirect (or predictive) measure, as are physical/chemical parameters.

Benthic invertebrates can be used as a barometer of overall biodiversity in aquatic ecosystems.

Invertebrate communities respond to changes in water/habitat quality, and integrate impacts over time because of their extended residency period in the stream.

Presence or absence of specific taxa can be indicative of specific environmental and habitat factors.

Invertebrates are abundant and diverse in most streams and rivers, and are relatively easy to sample and analyze.

They are relatively immobile and cannot avoid "events" or "pulses" of pollutants or other forms of stress often missed by conventional water or habitat quality sampling.

Aquatic invertebrates serve as the primary food source for many stream fishes.

For further information e-mail Robert W. Wisseman at aquaticbio@mac.com.

Additional web sites containing bioassessment and biomonitoring information are:

1. Northwest Bioassessment Work Group at www.epa.gov/r10earth/offices/oea/aqbioass.html

2. Oregon Department of Environmental Quality at www.deq.state.or.us/lab/lab.htm

3. North American Benthological Society at www.benthos.org