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Diagnostic Capability
The diagnostic capacity of bioassessment data and results is dependent on the development of patterns and response signatures from a database that includes a variety of stressors and the full gradient of human disturbance and biological response. This increases the value of biological data beyond the determination of status (attainment/non-attainment) to include inferences and decisions about causal associations and elimination of candidate causes in a stressor identification process. The development and use of a diagnostic capability is only possible within programs that have specifically developed methods and for which precision and accuracy issues have been addressed.
Some Frequently Asked Questions
Question: What is required to use biological information as a basis for diagnosing problems?
Figure 1:
Answer: Appropriately detailed biological information is needed to discriminate between different categories of stressors; however, it requires underlying analyses of large datasets to reveal patterns of biological response. Tolerances of individual taxa within a family can differ; thus, diagnosis of biological impairment will rely heavily on genus level taxonomy. Family level tolerance values should be used with caution because they are a non-weighted average of a potentially wide range of tolerances (See Figure). The overall performance of weighted averaging models to develop tolerance values consistently showed that genus-level taxonomy had better precision and performance in predicting environmental conditions in streams.
Learn more about diagnostic capability:
- Causal Analysis/Diagnosis Decision Information System (CADDIS)
- Understanding Biological Responses in Lessons Learned for Bioassessment
- Development and Application of Multimetric Indexes in Developing Biological Indicators: Lessons Learned from Mid-Atlantic Streams
- Linking Human Disturbance To Biological Change in Developing Biological Indicators: Lessons Learned from Mid-Atlantic Streams
- The Stressor Identification Process module from the 2003 National Biocriteria Workshop
- Using Bioassessments and Biocriteria to Identify Impaired Waters and Causes of Impairment - Case Study