IBI’s: An Introduction

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.

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

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

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

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

Fish as Environmental Indicators

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)

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)

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)

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