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Aquatic Life Use Support (ALUS)
Biocriteria Links
Additional Information
Habitat Structure
Interpretation of biological data in the context of habitat quality provides a mechanism for discerning the effects of physical habitat structure on biota from those of chemical toxicants. If habitat is of poor or somewhat degraded condition, expected biological values are lowered; conversely, if habitat is in good condition (relative to regional expectations), high biological condition values are expected. Poor habitat structure will prevent the attainment of the expected biological condition, even as water quality problems are ameliorated. If lowered biological values are indicated simultaneously with good habitat assessment rating scores, toxic or conventional contaminants in the system may have caused a suppression of community development. Additional chemical data may be needed to further define the probable causes (stressors). On the other hand, high biological metric scores in poor habitat could indicate a temporary response to organic enrichment, natural variation in colonization/mortality, change in predation pressures, change in food source/abundance, or other factors.