Environmental status assessment using biological traits analyses and functional diversity indices of benthic ciliate communities.

In this study, we tested the hypothesis that the functional diversity of benthic ciliates has high potential to monitor marine ecological status. Therefore, we investigated the spatial and temporal variation of functional diversity of benthic ciliates in the Yangtze Estuary during one year using biological traits analyses and functional diversity indices. Traits and community compositions showed clear spatial and temporal variations. Among a variety of biological traits, feeding type and body size emerged as strongest predictable variables. Functional divergence (FDiv) had an advantage over two other functional diversity indices, as well as over classical diversity measures (i.e. richness, evenness, Shannon-Wiener) to infer environmental status. Significant correlations between biological traits, FDiv and environmental variables (i.e. nutrients, temperature, salinity) suggested that functional diversity of benthic ciliates might be used as a bio-indicator in environmental status assessments. Further mandatory researches need to implement functional diversity of ciliates in routine monitoring programs were discussed.