Abstract: In July and August, 2011, an investigation was conducted on the community structure of macrozoobenthos in the rocky intertidal zone of uninhabited islands in Dongtou County of Zhejiang. One sampling section was set up in each of the seven islands, including Dazhuyu Island, Hudong Island, Beipanshan Island, Luantou Island, Neiyuan Island, Xiaoqu Island, and Zhongqu Island. A total of 102 macrozoobenthos species were collected, including 58 species of mollusca (5 species of Polyplacophora, 33 species of Gastropoda, and 20 species of Bivalvia), 22 species of Crustacea, 7 species of Polychaeta, and 15 species of others. The average density and biomass of the macrozoobenthos were (864±126) ind·m^-2 and (1814.85±347.03) g·m^-2, respectively. One-way ANOVA showed that the average density and biomass of the macrozoobenthos differed significantly among different islands. The among-island differences in the average density and biomass of the macrozoobenthos were dependent on the lineages. There was a significant difference in the density of Polyplacophora, Gastropoda, and Crustacea, but not of Bivalvia, Polychaeta, and others among the islands. The biomass of Polyplacophora, Crustacea, and others, but not of Gastropoda, Bivalvia, and Polychaeta differed significantly among islands. The average density and biomass of the macrozoobenthos were greater in the mid-tide zone than in the low-tide zone or high-tide zone. There were significant among-zone differences in the density of Polyplacophora, Gastropoda, Bivalvia, Crustacea, Polychaeta, and others, and in the biomass of Bivalvia, Crustacea, and others, but no differences in the biomass of Polyplacophora, Gastropoda, and Polychaeta. The mean values of the Shannon diversity index, Margalef’s richness index, and Pielou evenness index were 2.79, 0.62, and 2.41, respectively. The results of clustering analysis on the community traits were consistent with those of nonmetric multidimensional scaling, suggesting that the community structure was mainly related to the substrate characteristics and wave-hitting degree.

Key words: monsoonal climate., random forest, integrity of biotic index (IBI), natural gradients