Vegetation Characteristics Of Riparian In Gan River

Using Braun—Blanquet field community investigation method to survey vegetation of Gan River riparian. As a mass of field survey, quantitative analysis of vegetation and environment, and quantitative analysis of vegetation succession, the aims were to known some character about the composition, distribution, succession of Gan River riparian communities. As the result following:1 708 species of seed plants affiliated to 405 genera in 119 families were discovered in riparian of Gan River based on field survey and analysis of geographical elements, where 32 species belonged to invasive plants were found. According to life-form classification of plants group, herbs (62.01%) are the dominants and deciduous component (71.67%) in woody plant, which reflects the characteristics of ecological environment in Gan River riparian. Further flora analysis indicated that there are intrazonal feature of vegetation in this distinct being of prevailing widespread families (39.50%) and genera (15.31%), and complex distribution types of plant genera. TTrop/TTemp value is 1.02 embodied a transitional flora trait. Cluster analysis, principal component analysis and formula fitting implied the intersection of aquatic and land.2 The TWINSPAN clustering and DCA of riparian plant communities showed that:the communities could be primarily divided into 6 communities types, the 6 types of communities are:A Bench grass communities; B Terraces deciduous communities; C Washland meadow; D Terraces evergreen broad-leaved forest; E Hillside mixed needle forest; F Hilllock redpine forest. At the same time, classify the plant communities as Classical approach, the communities could be divided into 84 of association, which belong to 8 vegetation type. Compared with two kinds of vegetation classification method, the result of quantitative classification has more ecological significance, and the result of Classical approach has more systematicness.3 The CCA and DCCA ordination result show that:man-kind disturb (DIS), degree of landform (GRA) were the main factors that influence the vegetation of Gan River riparian. And analyses the diversity of riparian communities, DIS, pH, GRA were the key factor.4 Analysis the succession of Gan River riparian communities by index of succession, degree of succession, and succession probability analysis, combined the result of TWINSPAN and DCA, the result show that:the broad-leaved forest which dominant species were Cinnamomum camphora, Celtis sinensis and so on, which is the topographic climax community. And the succession series was:A→C→B→D, which was a succession sere along with landform transformation. As the succession, Patrick richness index, Margalef richness index, and Simpson diversity index of community increase. In other words, along with succession, the species diversity of community was raise.