Study on the features of vegetation in different landforms of peak forest plain in the north Guangdong

Aims to find out the relationship between vegetation community feature,species diversity and different landforms in karst peak forest.Two peak which are typical karst peak forest plain system in Jiulong town,Yingde City of northern Guangdong Province were selected as the research area. Plants variety, soil thickness, coverage of vegetation，biomass were investigated respectively by quadrat method at summit, cliff, slope foot, and peak forest depression in two peak. The biodiversity，such as Shannon-Wiener index, Simpson index and Pielou index were analyze with SPSS 10.0 and compared with different landforms.The Jaccard correlation coefficient were adopted to discuss similarity among the different landforms.The results showed,(1)The coverage of rock and soil thickness are more different among the summit, cliff, slope foot, and peak forest depression,and the coverage of rock in cliff plots is bigger significantly than others plots, and the soil thickness in peak forest depression is bigger significantly than others plots;(2)The association of summit, cliff, slope foot, and peak forest depression is Ficus microcarpa - Zanthoxylum armatum + Loropetalum Chinese - Ischaemum indicum, Ficus microcarpa - Alchornea trewioides + Loropetalum chinese - Miscanthus floridulus, Pistacia chinensis - Rubus tephrodes - Ischaemum indicum, Alangium kurzii - Acacia sinuate + Lingnania chungii - Loropetalum chinese, dominant species and synusia structure are more different among the different landforms; (3)There are higher coverage of vegetation in karst peak forest due to adaptations of most plants for karst environment, but the standing biomass in summit and peak forest depression which have gently slopes and more thicker soil is bigger significantly than that of cliff and slope foot;(4)There are significantly negative correlation between coverage of rock and soil thickness, soil thickness and standing biomass;(5) The species in summit and peak forest depression are fewer significantly than that of cliff and slope foot. Shannon-Wiener index, Simpson index and Pielou index in summit are fewer than others, but those index in cliff are higher significantly than others. The diversity of karst landform is contribute to biodiversity;(6)Analysis of Jaccard similarity coefficient demonstrate that spatial heterogeneity is a deciding factor for species distribution, especially the separation distance of the space and differences of landform. In brief，different landform of karst peak forest is an important factor which lead to the differentiation of vegetation community and biodiversity, but the adaptability of plant in karst area can weaken the effection of landform in a certain extent.