Adaptation and application of multivariate AMBI (M-AMBI) in US coastal waters

Abstract

The multivariate AMBI (M-AMBI) is an extension of the AZTI Marine Biotic Index (AMBI) that has been used extensively in Europe, but not in the United States. In a previous study, we adapted AMBI for use in US coastal waters (US AMBI), but saw biases in salinity and score distribution when compared to locally calibrated indices. In this study we modified M-AMBI for US waters and compared its performance to that of US AMBI. Index performance was evaluated in three ways: 1) concordance with local indices presently being used as management tools in three geographic regions of US coastal waters, 2) classification accuracy for sites defined as good or bad and 3) insensitivity to natural environmental gradients. US M-AMBI was highly correlated with all three local indices and removed the compression in response seen in moderately disturbed sites with US AMBI. US M-AMBI and US AMBI did a similar job correctly classifying sites as good or bad in local validation datasets (83 to 100% accuracy vs. 84 to 95%, respectively). US M-AMBI also removed the salinity bias of US AMBI so that lower salinity sites were not more likely to be incorrectly classified as impaired. The US M-AMBI appears to be an acceptable index for comparing condition across broad-scales such as estuarine and coastal waters surveyed by the US EPA's National Coastal Condition Assessment, and may be applicable to areas of the US coast that do not have a locally derived benthic index.

Adapting metabarcoding-based benthic biomonitoring into routine marine ecological status assessment networks

“…The WFD and MSFD directives, and the US EPA currently consider multivariate AMBI (M-AMBI) as a common approach to assess benthic conditions (Borja et al, 2009;Pelletier et al, 2018). The validation of a genomic-based M-AMBI (M-gAMBI) will favor the implementation of a common metabarcoding tool for such assessments worldwide.…”

Landscape structure and land use affect estuarine benthic invertebrates in the Virginian Biogeographic Province, USA

“…Although we know that estuaries tend to have distinct natural gradients from the mouth to the headwaters (Soetaert et al 1995, Rakocinski et al 1997, the benthic indices used in this study attempt to minimize some of the effects of these gradients by adjusting for salinity. U.S. M-AMBI is calculated for each salinity zone separately (Pelletier et al 2018) while the VP BI uses salinity-adjusted metrics ). Because we examined linkages between estuarine condition and the watershed, we needed to summarize estuarine condition for the entire estuary by taking the mean of all values within the estuary.…”

“…Invertebrates were summarized by two benthic indices -U.S. M-AMBI (Pelletier et al 2018) and the Virginian Province benthic index (VP BI; . U.S. M-AMBI consists of three metrics: the abundance-weighted tolerance index AMBI (Gillett et al 2015), Shannon's H' and species richness and was calculated separately for five salinity zones (i.e., tidal freshwater, oligohaline, polyhaline, euhaline, hyperhaline; Venice System 1958).…”

“…These assemblages have commonly been assessed using benthic indices that summarize aspects of the invertebrate community into a single number that can be used by environmental managers Summers 1999, Pinto et al 2009). For this study we used two benthic indices -the Virginian Province benthic index (VP BI; which was used by the U.S. EPA to assess estuarine condition from 1990 to 2010 and U.S. M-AMBI (Pelletier et al 2018) which was used to assess estuarine condition for the U.S. EPA's National Coastal Condition Assessment from 2015 onward. For both indices, we examined the mean estuary index value, as well as accounting for variation within the estuary.…”

Lessons Learned from 30 Years of Assessing U.S. Coastal Water

“…Because the different indices might not be comparable, combining the separate indices into a nationwide evaluation tool was problematic. In response, a nationalscale index called M-AMBI (multivariate-AZTI marine biotic index) was adapted to provide a single index applicable to all U.S. estuarine waters [48,49]. This index is based on benthic indices that were successfully deployed in Europe and elsewhere [50,51].…”