Quantitative Vegetation Classification of Qichai Region in Hainan Island

After species data and environmetal information were obtained based on vegetation surveys in Li minority region in Qichai,Hainan Island,a classification and ordination were made with PC-ORD software.After referring to the classification principles of"Chinese Vegetation",reviewing related research data such as"Guangdong Vegetation",and artificially adjusting quantitative classification results,the vegetation classification system of Qichai region was established.It includes three vegetation type groups,eight vegetation types,two formation groups and six formations.The six formations are discribed as Form.Bombax ceiba+Lannea coromandelica+Terminalia nigrovenulosa,Form.Pinus latteri,Form.Imperata arundinacea,Form.L.coromandelica+Kleinhovia hospital+B.ceiba,Form.Dacrydium pierrei+Syzygium araiocladum+Cyclobalanopsis bambusaefolia and Form.Vatica mangavhapoi+Ameslodendron chinense+Ficus altissima+Koilodepas hainanensis.The first axis of NMDS ordination expresses the gradients of soil moisture,while the second one depicts the height change of elevation.Therefore,plot arrangements in the axes are fitted with their practical distributions in the fields.The vegetation formation,distribution and change in the region may be related to its special climatic conditions and unique human activities of Li minority.