Niche and interspecific association of dominant zooplankton species near the Taishan coastal area in the South China Sea

Marine zooplankton communities represent one of the most diverse and abundant species groups on earth. To investigate the ecological niche characteristics and interspecific interactions of marine zooplankton, and to elucidate their role in carbon deposition and biogeochemical cycling, we conducted a study on the zooplankton community near Taishan in the South China Sea between December 2015 and September 2016. Using niche breadth, niche overlap, the variance ratio method, chi-square tests, and linkage coefficients, we analyzed the interrelationships among the major zooplankton species. Over four sampling seasons, we identified 61 species of zooplankton spanning 11 taxonomic categories. Copepods were the most abundant, comprising 32 species and accounting for 66.67% of the total. The niche breadth and overlap of dominant species displayed seasonal variation, with niche breadth ranging from 2.04 to 2.82, and niche overlap between species pairs ranging from 0.31 to 0.85. Correlation and interspecies association analyses revealed that interspecies associations near the Taishan coastal area in autumn and winter were generally significantly positively correlated. However, the relationships among the 18 dominant species groups during these seasons were not statistically significant (p > 0.05), indicating weak interspecies connectivity within the zooplankton communities in this region. Our findings also suggest that anthropogenic disturbances and seasonal variations influenced the zooplankton community, contributing to its structural instability.