Download Definitions

An Introduction to
Indexes of Biotic Integrity
and the Use of Fish
Assemblages in Biological
Assessments
Definitions
Biological Integrity

The capability of supporting and
maintaining a balanced, integrated,
adaptive community of organisms
having a species composition, diversity,
and functional organization comparable
to that of natural habitats of the region
(Karr and Dudley 1981).
Bioassessment

Evaluation of the biological condition of
a waterbody that uses biological
surveys of the resident biota
Biosurvey

Collection,
processing, and
analysis of
representative
portions of a
resident biotic
community or
assemblage
Biocriteria


Numerical value or statement that
defines a desired biological condition for
a waterbody
Mandated under the Clean Water Act as
part of WQ standards
Reference Condition



“Best Available”
conditions where the
biological potential is
at its highest for a
particular region
Representative of
sustainable
ecosystem health
Provides a standard
for comparisons
Metric

Characteristic of the
biota that changes
predictably with
increased human
influence
Multimetric Index

Combines indicators, or metrics, into a
single index value. Each metric is
tested and calibrated to a scale and
transformed into a unit-less score prior
to being aggregated into a multi-metric
index. Both the index, and metrics, are
useful in assessing and diagnosing
ecological condition.