| The Tunchang area of central Hainan refers to the middle transition zone between the tropical rain forest area in central Hainan and the coastal area of Hainan.It is rich in natural resources and has a variety of rare and endangered protected plants.It is a key area of eco-environmental protection in China.In recent years,many scholars have studied the characteristics and diversity of plant communities in Wuzhi Mountain in the central part of Hainan Island,Jianfengling Mountain in the south,Ganshiling Mountain in the south,Yingjialing in the south-central part,and Diaoluo Mountain in the southeastern part of Hainan.But there are few studies on the characteristics and diversity of secondary forest communities in hilly areas of central Hainan.In this study,the secondary forest vegetation in hilly area of central Hainan is taken as the research object,and the research on secondary forest vegetation flora,geographic composition,species diversity,community diversity and interspecific association are carried out.The results of the study show that:(1)there were 79 families,184 genera and 258 species of vascular plants in the investigated plots,including 3 families,3 genera,4 species,gymnosperms,2 families,2 genera,2 species,and angiosperms 74 species.There are some ancient relic species,which are rich in wild vascular plants.At the same time,there are a variety of precious medicinal materials and tree species such as Madhuca haianensis?Heritiera parvifolia?Aguilaria sinensis?Dendrobenthamia Angustata.The dominant families were Euphorbiaceae?Rubiaceae?Leguminosae?Rosaceae?Sterculiaceae and Lauraceae,The main subjects are small families and single families,and the main constituents of genus and species are major subjects,large subjects,and medium subjects;small genera and single genera form the main body of the genus of seed flora in this area.(2)The tropics of the flora are obvious,with rich species diversity,complex geographical composition,the floristic origin is ancient,and the seed plants in the community can be divided into 10 distribution types and 4 subtypes,79 families.There are 15,57 and 7 families in the world distribution,tropical distribution and temperate distribution respectively.It shows that there are obviously 184 genera of tropical species,only one in the world,153 in the tropical and 30 in the temperate zone.The species composition of the family is 89.06%and 83.60%of the tropical components(not including the worldwide distribution of genera,the same below),and the temperate components are 10.93%and 16.39%respectively,indicating that the tropical distribution is the main component.(3)The vertical structure of community in hilly area of central Hainan is divided into arbor layer,shrub layer and herbaceous layer.R(Margalef index):shrub layer>tree layer>herb layer;H(Shannon-Wiener index):shrub layer>herb layer>tree layer;D(Simpson index):shrub layer>herb layer>tree layer;E(Pielou index):herb layer>shrub layer>tree layer,In the early stage of community succession,shrub layer the vegetation layer is compared with the local habitat.The comparison of species diversity among different community types shows that the 27-year-old secondary forest has the highest species diversity.(4)The secondary forest community in the hilly area of central Hainan Province shows no significant positive correlation.The dominant species in the community was loosely connected,and the interspecies relationship of the dominant species was not close as a whole,and it was in the early stage of succession.In the community,Schefflera octophylla?Cratoxylum cochinchinense?Aporusa dioica and Lasianthus Koi?Ormosia pinnata?Scleria hebecarpa Nees?Ottochloa nodosa?Merremia boisiana are associated with a large number of species and have a wide range of distribution.In practice,positive coupling should be strong.The tree species are protected to reduce the succession of forest communities in hilly areas of central Hainan. |
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