Aquatic Life Use Support (ALUS)

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Table 1. Hierarchy of Bioassessment Approaches for Evaluation of Aquatic Life Use Attainment Based on Resident Assemblages

Level of Info ^a Technical Components Spatial/Temporal Coverage Data Quality ^b

1 Visual observation of biota; reference conditions not used; simple documentation Limited monitoring; extrapolations from other sites Unknown or low precision and sensitivity; professional biologist not required

2 One assemblage (usually invertebrates); reference conditions pre-established by professional biologist; biotic index or narrative evaluation of historical records Limited to a single sampling; limited sampling for site-specific studies Low to moderate precision and sensitivity; professional biologist may provide oversight

3 Single assemblage usually the norm; reference condition may be site-specific, or composite of sites (e.g., regional); biotic index (interpretation may be supplemented by narrative evaluation of historical records) Monitoring of targeted sites during a single season; may be limited sampling for site-specific studies; may include limited spatial coverage for watershed-level assessments Moderate precision and sensitivity; professional biologist performs survey or provides training for sampling; professional biologist performs assessment.

4 Generally two assemblages, but may be one if high data quality; regional (usually based on sites) reference conditions used; biotic index (single dimension or multimetric index) Monitoring during 1-2 sampling seasons; broad coverage of sites for either site-specific or watershed assessments; conducive to regional assessments using targeted or probabilistic design High precision and sensitivity; professional biologist performs survey and assessment

NOTE: Table is based on use in lotic systems. With some modification, these approaches would apply to other waterbody types.

^a Level of information refers to rigor of bioassessment, where 1 = lowest and 4 = highest.

^b Refers to ability of the ecological endpoints to detect impairment or to differentiate along a gradient of environmental condition.

Biological Indicators

Level of Info ^a	Technical Components	Spatial/Temporal Coverage	Data Quality ^b
1	Visual observation of biota; reference conditions not used; simple documentation	Limited monitoring; extrapolations from other sites	Unknown or low precision and sensitivity; professional biologist not required
2	One assemblage (usually invertebrates); reference conditions pre-established by professional biologist; biotic index or narrative evaluation of historical records	Limited to a single sampling; limited sampling for site-specific studies	Low to moderate precision and sensitivity; professional biologist may provide oversight
3	Single assemblage usually the norm; reference condition may be site-specific, or composite of sites (e.g., regional); biotic index (interpretation may be supplemented by narrative evaluation of historical records)	Monitoring of targeted sites during a single season; may be limited sampling for site-specific studies; may include limited spatial coverage for watershed-level assessments	Moderate precision and sensitivity; professional biologist performs survey or provides training for sampling; professional biologist performs assessment.
4	Generally two assemblages, but may be one if high data quality; regional (usually based on sites) reference conditions used; biotic index (single dimension or multimetric index)	Monitoring during 1-2 sampling seasons; broad coverage of sites for either site-specific or watershed assessments; conducive to regional assessments using targeted or probabilistic design	High precision and sensitivity; professional biologist performs survey and assessment

Aquatic Life Use Support (ALUS)

Biocriteria Links

Table 1. Hierarchy of Bioassessment Approaches for Evaluation of Aquatic Life Use Attainment Based on Resident Assemblages

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