Spatiotemporal characteristics of carbon storage in mangrove communities at different restoration stages and its influencing factors in Hainan Province

The mangrove ecosystem is notable for its high carbon storage capacity and strong carbon sequestration potential. Optimizing carbon storage requires selecting mangrove species with high carbon density and ideal carbon sink environments. This study investigates coastal mangroves restored near the Tielu Port Mangrove Protection Area in Sanya, Hainan Province, by comparing carbon storage across mangrove communities of different ages, tidal elevations, and planting patterns. The aim is to understand the impact of various biological and environmental factors on mangrove carbon storage. Carbon storage in this study includes both plant and soil carbon storage. Plant carbon storage is estimated by measuring the biomass of above-ground and below-ground vegetation, as well as litter, while soil carbon storage is calculated by determining soil organic carbon. Results indicate that mangrove carbon storage typically increases with tree age, primarily due to the continuous accumulation of soil carbon. Additionally, mangroves at higher tidal elevations exhibit greater carbon storage compared to those at lower elevations. There is an interaction between tidal elevation and species, with tidal elevation influencing different species to varying extents. For 10-year-old mangrove and repaired communities in the study area, the carbon storage hierarchy is as follows: Sonneratia apetala > Avicennia corniculatum > Avicennia corniculatum + Laguncularia racemosa > Sonneratia apetala > Avicennia marina > Laguncularia racemosa, with respective carbon storage values of 305.52, 236.26, 178.15, 172.96, 145.99, 136.98, and 97.42 t hm⁻². This research provides a scientific basis for formulating effective mangrove carbon sink afforestation strategies.