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APPLICATION OF TWO INDICES OF BENTHIC COMMUNITY CONDITION IN CHESAPEAKE BAY
Citation:
Ranasinghe, J. A., J. B. Frithsen, F W. Kutz, J F. Paul, D. E. Russell, R. Batiuk, J. L. Hyland, J. Scott, AND D. M. Dauer. APPLICATION OF TWO INDICES OF BENTHIC COMMUNITY CONDITION IN CHESAPEAKE BAY. ENVIRONMETRICS 13(5-6):499-511, (2002).
Impact/Purpose:
The primary objectives of this research are to:
Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;
Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;
Develop and validate multivariate models based on quantification studies;
Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;
Complete an initial draft (potentially web based) of a national landscape condition assessment.
This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.
Description:
The Chesapeake Bay Benthic Index of Biotic Integrity (B-161) and the Environmental Monitoring and Assessment Program's Virginian Province Benthic Index (EMAP-VP BI) were applied to 294 sampling events in Chesapeake Bay and the results were compared. These benthic indices are intended to identify benthic invertebrate assemblages that have been degraded by low bottom dissolved oxygen concentrations or high concentrations of sediment chemical contaminants, that are the most common effects of pollution in estuaries. The B-IBI includes several benthic community measures and weights them equally using a simple
scoring system that compares them against values expected in undegraded habitats. It includes eleven measures of species diversity, productivity, indicator species, and trophic composition that vary from habitat to habitat. The EMAP-VP BI uses discriminant function coefficients to weight contributions of another measure of species diversity and the abundance of two indicator families. In our comparisons, the two indices agreed on degraded or undegraded classifications for benthos at 81.3% of the sites. This level of agreement is within the level of accuracy achieved during benthic index development and, therefore, may
approach the limits that can be achieved. The indices were strongly associated with Pearson and Spearman correlation coefficients of 0.75 and 0.74, respectively.