Diversity of macrobenthos and evaluation of ecological quality in intertidal zone of Jiangshan Peninsula, Beibu Gulf

Intertidal zone is a transitional zone between marine and terrestrial ecosystems, which is sensitive to human activities. To explore the diversity of macrobenthos in the intertidal zone of Jiangshan Peninsula under different disturbances ofhuman activity and evaluate its benthic ecological quality, we carried out a survey on macrobenthos in November 2023(Autumn) and April 2024 (Spring) in two intertidal transects (Bailongwei and Bailangtan) in Jiangshan Peninsula, Beibu Gulf. We analyzed the species composition, density, biomass, dominant species and biodiversity of macrobenthos, and evaluated the ecological quality status of these two intertidal transects by using the AZTI Marine Biotic Index (AMBI) and multivariate AMBI (M-AMBI). The results showed that a total of 87 taxa of macrobenthos were collected, among which Mollusks were the most abundant (41 species), followed by Annelida (21 species), Arthropoda (19 species), and other groups (Six species). The average density, biomass and Shannon diversity index of macrobenthos in spring were lower than those in autumn. The results of therelative importance index (IRI) indicate that there was an obvious change in the dominant species of macrobenthos in the two intertidal transects across the season. The results of the AMBI and M-AMBI indexes show that although the disturbance at the Bailongwei transect is slightly higher than that at the Bailangtan transect, the overall ecological quality of both transects isgenerally at a good level.