The impact of anthropogenic activities on intertidal macrobenthic biodiversity: A case study in northern Beibu Gulf, China

Abstract

Macrobenthos are crucial for maintaining the ecological balance of aquatic ecosystems. Given the high macrobenthic biodiversity of Beibu Gulf and its rapid economic development, this study evaluates the current state of the macrobenthic community and the impact of anthropogenic activities. The present study identified 82 macrobenthic species from the intertidal zones of northern Beibu Gulf, China, primarily mollusks (43.9%) and annelids (31.7%). The density and biomass of intertidal macrobenthos ranged from 113.45 ± 86.59 to 582.40 ± 179.07 ind./m² and 76.39 ± 111.46 to 786.12 ± 609.17 g/m², respectively. The Shannon-Weiner-Index, Margalef richness index, and Pielou evenness index ranged from 1.01 to 1.99, 1.38 to 2.52, and 0.80 to 1.38, respectively, suggested moderate anthropogenic influence. The dominant species were Pillucina vietnamica (Zorina, 1978), Cryptonetna producta (Kuroda & T. Habe, 1951), Praxillella cf. Affinis (M. Sars in G.O. Sars, 1872), Mictyris brevidactylus (Stimpson, 1858), and Cerithidea cingulata (Gmelin, 1791). One-way ANOSIM and MDS plots revealed that the intertidal macrobenthos formed three clusters: macrobenthos in the river mouth formed a single cluster, macrobenthos in areas with intensive human activity (factories, aquaculture, rural villages) formed another cluster, and macrobenthos in regions with less anthropogenic impact (near to urban city with sufficient sewage management system and nuclear power plant) formed a third cluster. Correlation analyses revealed that macrobenthos density, biomass, and biodiversity were mainly negatively associated with chlorophyll-a, total organic content, and sulfide levels. These findings provide valuable information on the current status of macrobenthic biodiversity in the northern Beibu Gulf, China. This information can serve as a guide for coastal planning and environmental management in the northern Beibu Gulf, China.