Key Factors

1
Translating diverse bioassessment data to detect
impairment the Potomac Basin-wide Index of
Benthic Integrity (B-IBI) L.E. Astin, ICPRB, 51
Monroe St. Suite PE-08, Rockville, MD 20850
lastin_at_icprb.org
Key Factors
Composite Index
Assessment Process

• Procedural steps
• Protocol details
• Taxonomic resolution
• Enumerations
• Site classes
• Reference criteria
• Index period
• Methods gears
• Study design

Integrative tool (B-IBI) to detect biological
degradation in the nontidal Potomac R. developed

• Comparability issues addressed
• Consistent taxonomy (Family)
• Consistent reference/impairment criteria from
  common abiotic parameters/measures
• Consistent site classes identified confirmed
  using reference sites
• Judgment sites matched to bioregions (Overton
  et al. 1993)

• Outcomes
• Standardized indicators based on departure from
  reference condition
• Consistent metric expectations (10th 50th of
  reference)
• Consistent metric scaling (1, 3, 5)
• Same-scale index scores
• Consistent index thresholds (5th 50th of ref)
  narrative categories (Good, Fair, Poor)
• Confirmed B-IBI response to stress in Potomac
  bioregions