Abstract:

We completed a quantitative investigation of the macrobenthic community in the intertidal zone and offshore areas of Zhangzi Island in November 2011 to identify the distribution and potential anthropogenic impacts on this aquatic community. Four biodiversity indices, Bray-Curtis similarity, MDS ordination analyses, and ABC curves were used in the present work to analyze the community structure. We identified 39 total macrobenthic species in the intertidal zone of Maya Beach, of which the most dominant groups were the Polychaeta, followed by Crustacea, and Mollusca. We found four dominant species belonging to Polychaeta, including Capitella capitata, Lycastopsis augenari, Naineris laevigata, and Lumbrineris latreilli. Average biomass of the intertidal zone was 25.76 ± 41.08 g/m², of which Mollusca contributed most. Average density was 315.11 ± 160.73 ind./m², of which the Polychaeta contributed most. The average value of three biodiversity indices were relatively low (Richness index 1.17 ± 0.89, Evenness index 0.74 ± 0.17 and Shannon-Wiener index 1.80 ± 1.09). We identified 40 species in the offshore areas, of which the most dominant group was Polychaeta, followed by Crustacea, Mollusca and Echinodermata. We also identified five dominant species in offshore areas, including Ophiopholis mirabilis, Amphioplus japonicus, Lumbrineris latreilli, Echinocardium cordatum, and Ophiura sarsiivadicola. The average value of biomass and density was higher in the offshore areas compared to that of intertidal zone, with 218.86 ± 152.24 g/m² and 700.00 ± 471.51 ind./m², respectively. The average value of Richness index was 1.40 ± 0.60, Evenness index 0.64 ± 0.19 , and Shannon-Wiener index 2.04 ± 0.78. MDS ordination analysis showed that community structure was significantly different within the intertidal zone and the offshore areas. Lastly, the macrobenthos fauna in intertidal zone were impacted by a moderate anthropogenic disturbance, whereas the fauna in offshore areas was slightly disturbed.

Key words: macrobenthos, community structure, biodiversity, Zhangzi Island, Yellow Sea