Seasonal implications for taxonomic sufficiency to simplify M-AMBI methodology in the coastal area adjacent to a eutrophic estuary

Taxonomic sufficiency (TS) refers to identifying taxa to a taxonomic level sufficient to detect community changes in stressed environments and may provide a cost-effective approach in routine monitoring programs. However, there is still limited information regarding the seasonal impact of applying TS and its implications for the ecological quality evaluation in the estuarine ecosystem. This study investigated the relationship between the multivariate-AZTI’s Marine Biotic Index (M-AMBI) and environmental variables in three seasons (i.e., spring, summer, and autumn) in the Liaohe River Estuary. We tested the reliability of TS for simplifying the M-AMBI methodology. The results showed that family and genus level data could reproduce the spatial-temporal patterns of community structure at the species level. The M-AMBI values showed a consistent spatial distribution pattern in all sampling seasons, with a decreasing trend with the increasing distance from the estuary mouth. Both genus and family level data performed nearly as well as species level in detecting the seasonal variations of pollutants (i.e., nutrients and total organic content). The family level M-AMBI was feasible to discern stress in the Liaohe River Estuary because of the high aggregation ratios at different taxonomic levels in all sampling seasons. These findings suggest that applying taxonomic sufficiency based on the M-AMBI provides an efficient approach for evaluating ecological quality in the Liaohe River Estuary.