Distribution Characteristics of Meiofaunal Community in Mangrove Wetland of Dongwei, Guangxi

To explore the distribution characteristics of meiofauna communities across mangrove vegetation types and internal microhabitats, an investigation was conducted in September 2021 at the Dongwei Mangrove Reserve in Guangxi Zhuang Autonomous Region. The spatial distribution of meiofauna in Kandelia obovata, Avicennia marina, Aegiceras corniculatum, Excoecaria agallocha, bare flat and internal microhabitats (sediment and leaf litter) was studied, and the influencing factors were analyzed. 10 and 11 meiofaunal taxa were identified from sediment and leaf litter, respectively. The average abundance of meiofauna in sediment was (577.22±448.52) ind.·10 cm^-2 with an average dry mass biomass of (502.33±379.25) μg·10 cm^-2. The average abundance of epiphytic meiofauna on leaf litter was (28.36±21.21) ind.·g^-1 with an average dry mass biomass of (26.14±5.57) μg·g^-1. The abundance and biomass of both sediment and leaf litter meiofauna varied significantly among habitats. No significant correlation was observed between the abundance and biomass of sediment meiofauna and the measured environmental factors. The abundance of epiphytic meiofauna on leaf litter was significantly and positively correlated with the chlorophyll a content and the pheophorbide a content of surface sediment, and biomass was significantly and positively correlated with the chlorophyll a content of surface sediment and the cellulose condensed tannins content of leaf litter. There were significant differences in meiofaunal community structure among habitats, with organic carbon content best explaining sediment meiofaunal community structure, and the combination of environmental factors, including chlorophyll a content and organic carbon content best explaining the community structure of meiofauna on leaf litter. Significant differences in meiofaunal communities between sediment and leaf litter were also observed. The results indicated that the spatial distribution of the meiofauna community in the wetlands was influenced by the combined effects of vegetation coverage, vegetation type and microhabitat type. The spatial heterogeneity of available food resources might be the primary environmental factor shaping the attributes of the meiofaunal community distribution.