Numerical classification and ordination of forest communities in Caohai basin

In this research,a typical sampling method was adopted to sample in forests of Caohai basin.And based on the data from 22 sample plots,forest communities in Caohai basin were investigated using TWINSPAN and DCA and CCA in order to analyze the structure of the communities.(1)The results of TWINSPAN classification indicated that these quadrate were classified into 7 types based on the species of Caohai basin,and they were further verified in the DCA two-dimensional ranking diagram.(2)CCA ordination results showed that the contribution in descending order was elevation,aspect,slope,and slope position.The first axis expressed the gradient of altitude among the communities,indicating the function of temperature.On the other hand,the second axis showed significant correlation with slop and aspect,which suggested that humidity,illumination and other things played key roles in community assembly.The results also indicated that the distribution of the vegetation communities was mainly impacted by two environment factors including elevation and aspect.At the same time,the vertical distribution character was obvious.