Characteristics Of Secondary Forest Community In Lowland Area Of Country Changhao,Mountain Wuzhi,China

Located in the tropical rain forest area of central Hainan and rich in natural resources with many rare and endangered plants,the lowland secondary forest of Wuzhishan Mountain of Hainan is a key area for ecological protection in China.In recent years,many scholars have studied plant community characteristics and diversity in Wuzhishan,southern Jianfengling,Ganshiling in central Hainan Island,Yinggelingling in the south-central part,and Diaoluo Mountain in the southeastern mountainous area,while the study on the succession characteristics and diversity of the secondary forests in the lowland of Wuzhishan Mountain is rare.This paper focuses on the secondary forest vegetation in Wuzhishan,Hainan Province and the research on the fauna of secondary forest vegetation,the study of geographical composition,species change and species diversity in different succession stages,and the interspecific association of mature communities.The research shows:(1)Due to its good hydrothermal conditions,Wuzhishan area has formed a variety of vegetation ecosystems,resulting in a rich flora.According to statistics,there are 122 species of vascular bundles in the plot,belonging to 116 families and 116 genera,including 2 species of 2 families and 2 genera of ferns,2 families and 2 genera of gymnosperms and angiosperms in 56 families,118 species of 112 genera.There are some ancient relict species,rich in wild vascular plants.The region also has Aquilariaagallocha Roxb,Aquilaria sinensis,Euphorbiaceae,Rubiaceae,Leguminosae,Rosaceae,Sterculiaceae and Lauraceae,though the genera in species are rare with Weak differentiation.(2)The geographical composition of the fauna is complex,with obvious tropical nature and prominent transitionThere are 10 distribution types and 4 subtypes in 60 families,and 57 families in the tropical distribution account for the largest proportion of non-world distribution,accounting for 89.09%.The second is distribution of 7 families in temperate zone,accounting for 10.9%of the total number of families;184 genus is divided into 15 distribution types of 11 subtypes,of which the largest distribution of tropical distribution is 81.42%,the temperate distribution of the non-world 18.6%of the total number of distributions,determining the nature of the faunaThe complex and diverse geographical components and their proportional relationship show that the flora of the hilly area in central Hainan is widely connected with other areas.On the other hand,it shows the transitional and typical tropical feature of the flora of the hilly area in central Hainan.(3)This study shows the low-lying secondary forests of Wuzhishan Mountain have different succession stages in the process of becoming a top-level community.The diversity index first rises before the middle and preliminary stage of recovery,and then shows downward trend during middle-late stages of recovery.The dominant tree species in this study vary greatly.The oleander family in the early stage of development are the dominant arbor species,the dominant arbor species in the stage of middle and preliminary recovery are the Euphorbiaceae,and the dominant genus in the middle-late and late recovery stages are Cockroach.(4)The mature communities of the secondary forests in the lowland of Wuzhishan Mountain of Hainan showed no significant positive correlation.The dominant species of the community were loosely connected,and the interspecific relationships of dominant species were not tight overall,which was in the early stage of succession.(5)On basis of the connection analysis,the forests with high degree of connection must be strictly protected;the red line of tourism should be delineated to prohibit all human activities for sake of the climax community and its succession to the climax community.For forests with moderate connectivity,we should adopt mountain closure to protect the forest gaps and promote the growth of ecologically associated tree species in the secondary forest and increase the species diversity of the tree layer and shrub layer;protect the litter and coarse woody residues under the forest,increase the soil organic matter and Nitrogen input to promote successful succession of communities.For forests with low connectivity in low-altitude areas,operate in differentiation.The forests in the early stage of succession,strict enclosure measures will be taken to avoid the interference of human activities and accelerate the natural succession of forests.Strengthen the cultivation and reproduction of pairs of species with high correlation and improve the connection between tree species.(6)Meanwhile,on basis of the analysis of succession characteristics,the forest community with long recovery must be strictly protected with hill closure and ecological red line,all human activities should be prohibited to protect the top community and promote its succession to the top community.For forest communities with medium recovery length:adopt mountain closure to protect the forest gaps and promote the growth of ecologically associated tree species in the secondary forest and increase the species diversity of the tree layer and shrub layer;protect the litter and coarse woody residues under the forest;increase the soil organic matter and Nitrogen input to promote successful succession of communities.For forest communities with medium recovery length:strict enclosure measures will be taken to avoid the interference of human activities and accelerate the natural succession of forests.At the same time,take site conditions as well as stand density into full consideration,ensure regular thinning and trimming of branches,which will help the restoration of secondary forest plant diversity and the improvement of vegetation structure,thus promoting the restoration of ecosystem functions.