Abstract: From July 2015 to June 2016, macrobenthos samples from three sub-habitats, including tidal creek, bare beach, and salt marsh, were collected monthly in the salt marsh wetland in the Yangtze Estuary to analyze community composition and diversity. The results showed that 21 species of macrobenthos were recorded, belonging to four phyla, five classes and 15 families. Among them, seven species were from Malacostraca and four species from Polychaeta. There was no difference in dominant species between the tidal creek and salt marsh subhabitats. The richness of macrobenthos species was the highest in salt marsh, followed by the tidal creek and lowest in the bare beach. The density and biomass of macrobenthos in the salt marsh were higher than those in other subhabitats. The density of macrobenthos differed significantly among the three sub-habitats (P<0.05), but without difference in biomass among sub-habitats (P>0.05). The Shannon diversity index of macrobenthic community in the salt marsh was the highest (1.08), followed by the bare beach (1.03), and the lowest in the tidal ditch (0.63). Simpson species richness index and Pielou species evenness index were higher in the bare beach than those of the tidal creek and salt marsh, indicating that the species distribution of benthic communities in the bare beach was more even than in other sub-habitats. Results from community clustering and non-metric multidimensional scaling analysis showed that macrobenthos community structure in the salt marsh and tidal creek sub-habitats were similar, but differed from that in the bare beach. The main contributors to such differences were Ilyoplax deschampsi, Corbicula fluminea,andNotomastus latericeus.

Key words: leaf trait, grazing gradient, Stipa krylovii steppe., life-form functional group