Scleractinian coral community structure and distribution in the coastal waters surrounding Hainan Island

Abstract

Based on the classical morphological and molecular taxonomy, 55 scleractinian coral species, belonging to 17 genera and 10 families, were recorded in five different coastal areas (Yunlong Bay, Wenchang; Dazhou Island, Wanning; Linqiangshi Island, Danzhou; Shayutang Village, Changjiang; Luhuitou, Sanya) of Hainan between 2014 and 2015. The dominant families included Acroporidae, Poritadae and Faviidae. The community structures of coral reefs in the five coastal areas were different. In Sanya, located in the south of Hainan, branching Acropora corals dominated the coral communities. In Wenchang and Wanning, on the eastern coast of Hainan, the laminar and branching Montipora corals were the dominant groups. In contrast, the mass corals Poritadae and Faviidae dominated the western coast in Danzhou and Changjiang. Analyses of community structure indicated that different geographic environments regulated successional differences. Coverage rates and diversity index values had a positive correlation and were as follows: Sanya > Wenchang > Changjiang > Wanning > Danzhou. Compared with the data obtained between 2005 and 2010, the coverage rates and diversity index values increased in Wenchang and Wanning and were relatively stable in Sanya and Changjiang, but showed an obvious decrease in Danzhou. However, the death rate of scleractinian corals was the highest in Changjiang, and most of the corals died within the last six months of 2015. In our opinion, human activities (including both protective and destructive activities) greatly affected coverage rates, death rates and diversity of the coral reefs.