Spatial patterns of the mangrove along the riverine estuaries, Nanliujiang River and Dafengjiang River of the Beibu Gulf

Mangrove growing on the tidal flat is of important value for the estuarine plant community compositions and coastal protection against wind and wave. This study aims to explore the spatial distribution pattern and associated influencing factors of estuarine mangrove based on the soaking and sinking experiment of aboriginal Aegicer-as corniculatum embryo and observations on water salinity, plant community structure and geomorphology of the tidal flat along the estuaries of Nanliujiang River and Dafengjiang River. Our results show that the distribution pattern of mangrove along Nanliuujiang River and Dafengujiang River estuaries exhibits a mode of “pure mangrove (e.g. mixture of Aegiceras corniculatum, Kandelia candel, Sonneratia apetala)→mixture of mangrove and semi-mangrove (Hibiscus tiliaceus, Clerodendrum inerme Gaertn)→mixture of mangrove, semi-mangrove and non-man-grove→mangrove mosaic→sparse mangrove seedlings” from sea to land. However, mangrove at the landward limit-ation of the Dafeng River estuary is characterized by a mixture of mangrove, mangrove seedlings and semi-man-grove. Besides, the time length of mangrove socking dominates the spatial distribution pattern of the estuarine mangrove while the time length of landward transport of tidal current affects the extreme location of the mangrove landward growth. A suitable tidal flat is an essential condition for the mangrove development and growth.