| In order to provide scientific basis for Yellow Camellia and its ecosystem's plant diversity conservation,management and use,this paper studies comprehensively and systematically on the plant flora,classification of vegetation,structure of communities,interspecific association and niche of dominant species,etc,of Fangcheng Yellow Camellia National Natural Reserve in Guangxi.The main results are as follows:(1)There are 1387 species(including varieties,subspecies and forms) which belong to 662 genera and 182 families in Fangcheng Yellow Camellia National Natural Reserve.Of all the plants,there are 83 species of fern plants, belonging to 50 genera and 26 families;11 species of gymnosperm,belonging to 6 genera and 6 families;1293 species of angiosperm,belonging to 606 genera and 150 families(Of all the angiosperm,there are 1069 species of dicotyledonous,belonging to 473 genera and 128 families;224 species of monocotyledon,belonging to 22 genera and 133 families).(2)By the statistics and analysis on the floristic composition of spermatophytes in Natural Reserve,the results are shown that in all the 148 families of seed plants,the families belonging to tropic type(97 families)is on the top position,accounting for 65.54%of families.In the 554 genera,the pan-tropic type(136 genera)is on the top position,accounting for 24.55%of genera.That shown the flora of the area has a strong conspicuous characteristics of the tropical.(3)The plant flora of Fangcheng Yellow Camellia National Natural Reserve is analyzed,and the characteristics are concluded as following:①The flora of this area is characterized with rich species and the tropical ingredients have dominant position.②There are rich endemic elements in this area.③The flora derives from ancient origin,the components of geography are complex.④the rare and endangered plants are abundant and have a strong characteristic.⑤The flora are shown conspicuous characteristics of the tropical margin.⑥The vine and the forest landscape is remarkable.(4)The vegetation in Natural Reserve is classified according to the Chinese Vegetation Classification Unit and System,combining the characteristics of vegetation in this area,taking into account the community's appearance,structure,species composition,dynamic features and ecological environment.The vegetation can be divided into 5 vegetation type groups,8 vegetation type,and 27 formations.Then,the main characteristics of vegetation are studied and analysed.(5)The results of species richness,species diversity and species evenness of tree layer,shrub layer and herb layer of plant communities are:①The shrub layer has the highest species richness,tree layer is secondly,and the herb layer is the lowest;②The Shannon-Wiener index H' of species diversity is in the order:shrub＞herb＞tree,and also the Simpson index D of species diversity is in the order:shrub＞herb＞tree;③The Pielou index Jsw and Jsi of species evenness is in the order:shrub＞herb＞tree.(6)A series of techniques including the analysis of variance,x~2-test, association coefficient(AC),Jaccard index are used,based upon the 2×2 contingency table to examine the species association between 25 dominant species of Yellow Camellia communities in Fangcheng Yellow Camellia National Nature Reserve.The results are indicated that:the overall association between 25dominant species is significantly positive,which suggests that the community is stable.Among total 300 pairs in 25dominant species,4 species pairs exhibited extremely significantly positive association, 10 species pairs shown significantly positive association,5 species pairs shown extremely significantly negative association,8 species pairs exhibited significantly negative association.There are a low association degree among most pairs of species,they are relatively independent.(7)The niche breadth and niche overlapping of dominant species in Yellow Camellia communities are studied by using Shannon-Weaver index and Schoener index.The results are shown that:the more the niche breadths of populations are,the wider the adaptive range of species to ecological factors,the more extensive the distribution range of species.The more the niche overlapping of populations are,the more the ecological similarities between populations.The niche breadth of Camellia nitidissima,C.euphlebia and C.tunghinensis are shorter than other species,tending to specialized species,whose niche overlaps with other dominant species are short,and the competitions between them are not fierce.Some advices about conservation,management and use of Yellow Camellia and its ecosystem's plant diversity are put forward,based on the research on the present status and reasons for dying of Yellow Camellia in Natural Reserve.
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