Spatial pattern and driving factors of carbon storage in mangroves along Leizhou Peninsula, China

• Mangrove carbon storage in Leizhou Peninsula displayed a pattern of being higher along the western coastline. • The relative abundance of Rhizophoraceae species facilitated carbon stocks in mangroves. • Mangrove carbon storage increased with vegetation diversity, particularly in high intertidal zones. • Soil physical mineral protection played significant roles in the accumulation of soil carbon pool. Mangrove ecosystem is known for its productivity with high carbon density. However, the mechanisms controlling carbon storage in mangroves remain poorly understood. Therefore, a field survey was conducted to explore mangrove carbon storage and driving factors based on 11 transects and 90 plots along the coastline of Leizhou Peninsula. The results showed an average ecosystem carbon density of 170.93 t/ha, with the highest values observed in Gaoqiao and Shiwei (transects D1 and D6), both situated along the western coastline. The capacity for carbon storage by mangroves was highly correlated with the performances of vegetation and stand structure. A positive association was observed between soil and vegetation carbon densities, whereas vegetation biomass production increased with tree stem diameter and tree height but decreased with tree density. Notably, carbon densities in mangrove stands were positively correlated with the relative abundance of Rhizophoraceae species. The data also demonstrated a significant promotional effect on carbon storage, particularly in high intertidal zones, attributed to vegetation diversity. In addition, the abundances of soil reactive minerals (e.g., clay and amorphous iron oxides) were also found to be positively correlated with soil carbon storage. In conclusion, these findings not only deepen the understanding of the function of carbon storage by mangroves, but also provide guidance for blue carbon management in mangroves.