Influence of Tianjiaotan Hydraulic Project on Ecology of Mangrove Forest in Xinying Bay

The construction and operation of Tianjiaotan Reservoir have changed the hydrological characteristics of Beimen River channel under the dam and affect the area of dilution zone,salinity,saltwater intrusion distance,and sediments in Beimen River estuary,which will further affect the growth and reproduction of the mangrove forest in Xinying Bay.This article investigates the current ecological status of the mangrove forest in Xinying Bay of Beimen River and establishes a mathematic model for planar two-dimensional salinity diffusion in Beimen River estuary by adopting three key factors affecting the growth and reproduction of the mangrove forest,such as the area of dilution zone,salinity,and saltwater intrusion distance.In addition,the article analyzes the influence of Tianjiaotan hydraulic project on the ecology of the mangrove forest.The results show that the salinity change of the estuary has little effect on the adult plants in the mangrove forest (with growth stress mainly observed) but limits the growth and development of seedlings.The increase in saltwater intrusion distance in the flood season can stimulate the upward development of the mangrove forest along the river;the decrease in the area of dilution zone in Xinying Bay may change the structure of the mangrove community in the estuary in a way that benefits the growth of salt-tolerant mangrove plants such as Avicennia marina and Rhizophora stylosa and affects the growth and development of salt-intolerant mangroves plants.The research results can provide a theoretical basis for the ecological conservation of the mangrove forest in Xinying Bay.