CALCULATING AN INDEX OF BIOTIC INTEGRITY IBI BRIEF
CALCULATING AN INDEX OF BIOTIC INTEGRITY (IBI) BRIEF OVERVIEW OF PROCEEDURE Metrics measured based on predicted response to stress Sub-set selected based on applicability to study (usually 8 -12) Scored according to predetermined criteria (often 0 -10) Aggregated by predetermined equations METRICS USED BY DIFFERENT STATES Taxa Richness-Based Metrics Composition-Based Metrics Tolerance-Based Metrics Based on Trophic Structure or other habits
CALCULATING AN INDEX OF BIOTIC INTEGRITY (IBI) METRICS CALCULATED FOR MACROINVERTEBRATES Taxa Richness-Based Metrics Metric Total taxa EPT taxa Ephemeroptera taxa Plecoptera taxa Trichoptera taxa Dipteran taxa Chironomidae taxa Long lived taxa POET taxa Odonata taxa Predicted response to Stress Decrease Decrease Increase Decrease
Composition-Based Metrics Abundance % Oligochaetes % Chironomidae % very tolerant % legless % Crustacea + Mollusca % Tanytarsini to Chironomidae % other Diptera and non-insect % dominant taxa (1 or 2 taxa) % Diptera % Corbicula % Ephemeroptera % Trichoptera % Plecoptera Variable Increase Decrease Increase Variable Decrease
Tolerance-Based Metrics Intolerant taxa Sediment-intolerant % sediment tolerant Hilsenhoff Biotic Index (HBI) Intolerant snail and Mussel taxa Decrease Increase Decrease Metrics Based on Trophic Structure or other habits % predators % scrapers % gatherers % filterers % omnivores % shredders % mud burrowers Clinger taxa Ratio of scrapper/filterer Decrease Variable Increase Decrease
Taxa Richness-Based Metrics Metric Predicted response to Stress EPT taxa Chironomidae taxa Odonata taxa Decrease Composition-Based Metrics % very tolerant % other Diptera and non-insect % dominant taxa (1 or 2 taxa) Increase Tolerance-Based Metrics % sediment tolerant Hilsenhoff Biotic Index (HBI) Increase Metrics Based on Trophic Structure or other habits % shredders Decrease Ratio of scrapper/filterer Decrease
CALCULATING AN INDEX OF BIOTIC INTEGRITY (IBI) BRIEF OVERVIEW OF PROCEEDURE Metrics measured based on predicted response to stress Sub-set selected based on applicability to study (usually 8 -12) Scored according to predetermined criteria (often 0 -10) Aggregated by predetermined equations METRICS USED BY DIFFERENT STATES Taxa Richness-Based Metrics Composition-Based Metrics Tolerance-Based Metrics Based on Trophic Structure or other habits
Taxa Richness-Based Metrics Metric Predicted response to Stress EPT taxa Chironomidae taxa Odonata taxa Decrease Composition-Based Metrics % very tolerant % other Diptera and non-insect % dominant taxa (1 or 2 taxa) Increase Tolerance-Based Metrics % sediment tolerant Hilsenhoff Biotic Index (HBI) Increase Metrics Based on Trophic Structure or other habits % shredders Decrease Ratio of scrapper/filterer Decrease
CALCULATING AN INDEX OF BIOTIC INTEGRITY (IBI) BRIEF OVERVIEW OF PROCEEDURE Scored according to predetermined criteria (often 0 -10) Examples of differing criteria Species richness Percent dominance
Taxa Richness-Based Metrics Metric Chironomidae taxa Predicted response to Stress Decrease USE EMPIRICAL DATA TO DEVELOP SCORING CRITERIA Observed richness 120 112 102 83 61 47 35 24 18 2 Frequency Exceeded 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Score 10 9 8 7 6 5 4 3 2 1
Taxa Richness-Based Metrics Metric Chironomidae taxa Predicted response to Stress Decrease USE EMPIRICAL DATA TO DEVELOP SCORING CRITERIA Observed richness 140 125 110 102 83 61 47 32 18 11 3 Frequency Exceeded 1% 5% 10% 25% 40% 50% 60% 75% 90% 95% 99% Score 10 9 8 7 6 5 4 3 2 1 0
Taxa Richness-Based Metrics Metric Predicted response to Stress % Dominant Taxa (2 most abundant) Increase USE EMPIRICAL DATA TO DEVELOP SCORING CRITERIA Observed Dominance 87% 85% 74% 68% 55% 42% 32% 28% 15% 12% Frequency Exceeded 1% 2% 4% 8% 16% 32% 64% 80% 88% 92% 94% Score 0 1 2 3 4 5 6 7 8 9 10
Taxa Richness-Based Metrics Metric Predicted response to Stress % Dominant Taxa (2 most abundant) Increase USE EMPIRICAL DATA TO DEVELOP SCORING CRITERIA Observed Dominance 87% 85% 74% 68% 55% 42% 32% 28% 15% 12% Frequency Exceeded 1% 2% 4% 8% 16% 32% 64% 80% 88% 92% 94% Score 0 1 0 2 3 4 3 5 6 6 7 8 9 9 10
CALCULATING AN INDEX OF BIOTIC INTEGRITY (IBI) BRIEF OVERVIEW OF PROCEEDURE Metrics measured based on predicted response to stress Sub-set selected based on applicability to study (usually 8 -12) Scored according to predetermined criteria (often 0 -10) Scores aggregated by predetermined equations METRICS USED BY DIFFERENT STATES Taxa Richness-Based Metrics Composition-Based Metrics Tolerance-Based Metrics Based on Trophic Structure or other habits
Taxa Richness-Based Metrics Metric Predicted response to Stress EPT taxa Chironomidae taxa Odonata taxa Decrease Composition-Based Metrics % very tolerant % other Diptera and non-insect % dominant taxa (1 or 2 taxa) Increase Tolerance-Based Metrics % sediment tolerant Hilsenhoff Biotic Index (HBI) Increase Metrics Based on Trophic Structure or other habits % shredders Decrease Ratio of scrapper/filterer Decrease
CALCULATING AN INDEX OF BIOTIC INTEGRITY (IBI) BRIEF OVERVIEW OF PROCEEDURE Metrics measured based on predicted response to stress Sub-set selected based on applicability to study (usually 8 -12) Scored according to predetermined criteria (often 0 -10) Scores aggregated by predetermined equations METRICS USED BY DIFFERENT STATES Taxa Richness-Based Metrics Composition-Based Metrics Tolerance-Based Metrics Based on Trophic Structure or other habits
The Interdisciplinary Nature of TMDL Science XXX Public Policy Aquatic Ecology TMDL Watershed Hydrology Fluvial Geomorphology
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