REEF-BUILDING CORAL COMMUNITY AND EVOLUTIONARY CHARACTERISTICS OF THE FRINGING REEFS ON THE WEST COAST OF XUWEN COUNTY,LEIZHOU PENINSULA

Fringing reefs are well developed on the southwest coast of Xuwen County at the Leizhou Peninsula, southernmost tip of China mainland. They are the only fringing coral reefs remaining on the coast of the mainland. Living corals in the fringing coral reefs consist of Porites, Favia, Acropora, Favite, Montipora, Platygyra and Pavona, dominated by Acropora-Favia-Porites community. Molluscs and arthropods are the main dwelling organisms. According to the coral ecology and reef-flat topographic features, the Dengloujiao fringing reef on the west coast of Xuwen County can be divided into 4 zones from the shore to the sea:1) the intertidal zone covered by sand and gravel, 2) the subtidal inner reef-flat with coral fragment and bioclast deposits, 3) the subtidal outer reef-flat with sparse living corals, and 4) the subtidal reef-flat rim of living corals. Goniopora is the dominant species in subtidal outer reef-flat and reef-flat rim. Relative sea-level changes, sea surface temperature variations and coastal eutrophication influx significantly affect the growth of coral reefs. The fringing coral reefs are primarily formed in the mid-Holocene based on the analysis of reef development and evolution. Recent surveys on the coral reefs indicate that the environmental changes caused by climate changes, coastal civil construction and population increase resulted in the changes in dominant coral species in reefal area, and the dynamic changes in the coral community.