Application of two indices of benthic community condition in Chesapeake Bay

摘要: SUMMARY The Chesapeake Bay Benthic Index of Biotic Integrity (B-IBI) and the Environmental Monitoring Assessment Program’s Virginian Province (EMAP-VP BI) were applied to 294 sampling events in results compared. These estuarine benthic indices are intended identify invertebrate assemblages that have been degraded by low dissolved oxygen concentrations or high chemical contaminants. B-IBI includes several community measures weights them equally using a simple scoring system compares against values expected for undegraded sites. It 11 species diversity, productivity, indicator trophic composition. EMAP-VP BI uses discriminant function coefficients weight contributions diversity abundances two families. agreed on classifications benthos at 81.3% This level agreement is within accuracy achieved during index development and, therefore, may approach limits can be achieved. strongly associated (Pearson’s r ¼ 0.75). was more conservative than BI, classifying 72.7% disagreements as degraded. 55 sites where disagreed distributed different habitats throughout except polyhaline sand. Many classification with close to, but opposite sides of, degraded–undegraded thresholds, 49.1% 0.5 units 81.8% 1.0 units; corresponding both only 23.4% 62.7%, respectively. pattern similar, 61.8% 74.6% 18.8% 38.9% agreements threshold. Although suggests either suitable evaluating condition, offers some additional advantages. Copyright # 2002 John Wiley & Sons, Ltd.