1. IBI’s: An Introduction

2. Concept of IBI
Multimetric index based on biotic communities that compares the condition of a waterbody to regional reference conditions
Uses a variety of metrics to best capture biological integrity
Metrics are adjustable depending upon region, objectives, etc.

3. Management Implications / Uses of Bioassessment Data
Identification and understanding of important stressors
Identification of impaired stream reaches and watersheds
Trend assessment
Uses all types of biological data; adapted to coldwater, estuaries, lakes, large rivers, wetlands, and caves

4. Advantages of IBI’s
Provides a standardized protocol for stream sampling
Inexpensive and quick
Integrates physical, chemical, and biological properties
Ability to detect a variety of impairments
Elastic
Scores are easily comparable

5. Disadvantages of IBI’s
Loss of information
Reference condition (?????????)
Biotic communities are highly variable
Fails to account for temporal / spatial variation
Elastic / arbitrary
Typically do not account for biomass
Rare species often over emphasized

6. Components of IBI’s Water Chemistry Habitat Assessments
Biological Assessments
Periphyton
Macroinvertebrates
Fish

7. Fish as Environmental Indicators

8. Positive Attributes of Fish Communities
Accurate environmental assessment of health
Structure often constant during summer season
Persistent and resilient
Assess both regional and microhabitat condition
Long life span (3-10yrs)
Assimilate biological conditions predictably
(Simon, 1991)

9. Positive Attributes of Fish Communities
Visibility
Highly visible component of aquatic community
Aquatic life uses and regulation often characterized in terms of fish
(Simon, 1991)

10. Positive Attributes of Fish Communities
Ease of use and interpretation
Reduced effort for trend assessment
Reduced processing time
Distribution, life history, and tolerances for most fishes well documented
(Simon, 1991)

11. Fish IBI Metric Categories
Species Richness and Composition Metric
Indicator Species Metric
Trophic Function Metric
Reproductive Function Metric
Fish Abundance and Condition Metric