| Jinggang Mountain National Nature Reserve lies in the southwest of Jiangxi Province. It is situated at south part of Mid-subtropical zone (113° 39' -114° 23' Band 26° 27 1-26°40' N). It is a famous scenic spot, once played an important role in the revolution in China. Some species of Castanopsis are the major specie of zonal vegetation -evergreen broad-leaved forest in Jinggang Mountain area. There are many varieties of forests containing Castanopsis in this region, covering a large area of Jinggang Mountain. In this paper, floric analysis, numerical classification, analysis of species diversity and interspecific association of the major species were carried out for Castanopsis communities in Jinggang Mountain, by adopting quadrat method, regarding altitude as dominant factor.1. There are 214 species of vascular plants in the Castanopsis communities in Jinggang Mountion (including varieties), belonging to 75 families and 132 genera, in which the pteridophyte accounted for 14 families 19 genera and 24 species, the gymnosperm 3 families, 4 genera and 4 species, and the angiosperm 58 families, 109 genera and 186 species, they took the proportion of the total plants in Jinggang Mountion by 29.15%> 15.85% and 7.44%, respectively.2. The floric characteristics of the Castanopsis communities:(1) The flora is complicated and transitional. The tropical families dominated the whole vascular plants with the exception of 13 cosmopolitan families, there were 44 tropial families which accounted for 70.97% of the total families. Moreover, the majority of them were 33 pan-tropical, families;17 temperate families which accounted for 27.42%of the total familes, and 1 family endemic to China which accounted for 1.61% of the total families. The tropical genera were the dominaint genera with the exception of 9 comopolitan genera in Castanopsis communities, there were 77 tropical genera, which accounted for 62.6% of the total gonera. Moreover, the majority of them were pan-tropical and tropical Asian genera. There were 41 temperate genera, accounting for 33.33%, and 5 genera endemic to China, accountion for 4.07%.(2)The flora had come floristic constitents before Q uaterary and retains many floristic element before Quaternary.(3)There were many rare and endangered plants and endemic plants.3. A variety of methods including the tabular comparison of data, the tabular comparison of similarity coefficient, the nearest method and the group-average method of hierarchical agglomerative classification were used to carry out numerical analysis for Castanopsis communities in Jinggang Mountion. Based on the results. The 15 forest plots in Jinggang Mountion were divided into eight formations according to the important values of species in tree layer, they were Castanopsis eyrei formation, Castanopsis forgesii formation, Castanopsis fabri formation, Castanopsis tibetana formation, Castanopsis sclerophylla formation, Castanopsis lamontii formation, Castanopsis earless formation and Castanopsis fordii formation.Each formation of the castanopsis commnuities was in its stable stage, except that some plots had intruded deciduous trees due to human influence, these forests could resume their former stable states if management is enhanced.4. The species diversity of Castanopsis communities in Jinggang Mountion was analyzed, by using species richness, Simpson index, Shannon-wiener index and pielou index, the results are as follows.(1) Jinggang Mountion had high species diversity index, which did not alter too much between investigated plots, the variation patterns of species diversity of Castanopsis communities were similar whichever the index was used.(2) There was no significant variation in species diversity between formations.(3) Generally, the order of the magnitude of species diversity was: shrub layer > tree layer > herb layer. The variation of indices order was: herb layer>tree layer > shrub layer.(4) The species diversity of Castanopsis communities was not affected by...
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