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Development of a National-Scale Indicator of Benthic Condition for the National Coastal Condition Assessment.
Citation:
Hansen, V., T. Grayson, A. Hamilton, E. Leppo, Peg Pelletier, AND D. Gillett. Development of a National-Scale Indicator of Benthic Condition for the National Coastal Condition Assessment. Presented at CERF 2013, San Diego, CA, November 03 - 07, 2013.
Impact/Purpose:
Present results of development of national-scale benthic indicator, based on European M-AMBI, that will be used by NCCA to assess benthic condition in estuaries.
Description:
The US EPA has evaluated the application of a national-scale indicator of estuarine benthic condition for the National Coastal Condition Assessment (NCCA). Historically, in the National Coastal Condition Reports (NCCR I-IV), estuarine benthic condition was assessed by applying multiple regional multimetric benthic indices that were developed using different statistical methods, component metrics, and numerical scales. Combining these regional indices to assess estuarine benthic condition nationally has been criticized in previous peer reviews of the NCCRs. The US EPA recognized the potential value of having an estuarine benthic indicator that could be applied uniformly for future NCCRs. The Multivariate AZTI Marine Biotic Index (M-AMBI), developed in Europe, is widely used across different waterbodies to assess marine benthic condition under the Water Framework Directive (WFD). The M-AMBI combines AMBI, taxa richness, and diversity in a factor analysis to explore the response of soft-bottom communities to natural and anthropogenic changes in water quality, integrating long-term environmental conditions. We evaluated the applicability of M-AMBI to the NCCA through statistical validation analyses to ensure reasonable correspondence with both the original regional benthic indices and environmental stressors. The advantages of using M-AMBI in the NCCA include 1) use of a common approach that can be applied nationally with regional calibration; 2) acceptance as a valid method of assessing benthic conditions in Europe; and 3) an assessment scale that is the same across the US. We will present the modifications we have made to M-AMBI for US estuaries and the results of validation analyses to test the applicability of M-AMBI for use by the NCCA.