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Why Use Biological Indicators?
More than 30 years after it was passed, the Clean Water Act still challenges us to answer critical questions about the physical, chemical, and biological state of the nation's waters. One of the most meaningful ways of answering these questions is to observe directly the plants and animals that live in bodies of water. Because these biological indicators integrate, in themselves, the effects of various stressors, aquatic organisms and their communities reflect current conditions, as well as changes over time and cumulative effects. Biological indicators can show problems otherwise missed or underestimated.
The objective of the Clean Water Act is to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.
– Sec. 101 (a)
It is the national goal, that wherever attainable, an interim goal of water quality which provides for the protection and propagation of fish, shellfish, and wildlife and provides for recreation in and on the water be achieved by 1981.
– Sec. 101 (a)(2)
Assessing the condition of biological communities provides a basis both to determine ecological potential and to measure success in achieving that potential. Biological indicators and data are the hub for:
- setting protection or restoration goals;
- determining what to monitor and how to interpret what is found;
- prioritizing stressors and choosing control measures;
- and assessing and reporting the effectiveness of management actions.
The U.S. Environmental Protection Agency has endorsed biological integrity, through bioassessments, as an indicator of environmental condition and, more specifically, ecological health. It is unique among currently used indicators in that:
- it uses information gathered directly from the aquatic organisms and the biological community of which they are a part
- the biota that biological integrity is concerned with, is shaped by all environmental factors to which it is exposed over time, whether chemical, physical, or biological
- it combines multiple, community level, biological response characteristics into an indicator of cumulative environmental impacts
Links:
- Why Use Biocriteria and Bioassessment Data
- Uses of Biocriteria and Bioassessment Data
- 2003 National Workshop Modules
- Biocriteria Case Studies
- Rapid Bioassessment Protocols Training Module
- Biological Criteria Explained in the Federal Register (PDF) (pp, 28K, About PDF)
- Water Quality Program Highlights (PDF): Ohio EPA’s Use of Biological Survey Information by the Office of Water (pp, 736K, About PDF)
- EPA’s Final Policy (PDF) on the Use of Biological Assessments and Criteria in the Water Quality Programs (pp, 2.34MB, About PDF)