A comparative study on the macrobenthic community over a half century in the Yellow Sea, China

Over the past few decades, the ecological environment in the Yellow Sea has changed greatly from the impacts of global climate change and anthropogenic activities. In the present study, the biodiversity and community structure of the macrobenthos in the Yellow Sea were examined and were compared with data from a half century ago. Both quantitative and qualitative (grab and trawl) data on the soft-sediment macrobenthos from 2007 were used to study and compare the composition, distribution, abundance and biomass. Agglomerative classification and multidimensional scaling methods were applied to identify the macrobenthic communities, and the structure of these communities was compared with characteristic species-designated communities that were sampled nearly 50 years ago. Multivariate methods were used to detect relationships among environmental variables and species distribution and community classifications. A total of 267 species were collected with 58 grab samples, and 311 species were collected at 32 trawl sites. Nine quantitative and five qualitative clusters from 2007 were identified. These were classified into two groups of communities: The deep-water communities remained Yellow Sea cold water mass communities in species composition and were dominated by cold water species. The shallow-water communities, including previously reported mixed communities and eurythermal communities, were dominated by widely distributed polychaetes, with most of the previously dominant species exhibiting decreased abundance or lack of presence. The depth, temperature and salinity were the major environmental variables influencing faunal patterns. The subset of depth and temperature exhibited the maximum correlation with the biotic matrix.