Species diversity of forest communities in Pangquangou Nature Reserve,Shanxi of China

Based on the numerical classification of the forest communities in Pangquangou Nature Reserve of Shanxi by Two-Way Indicator Species Analysis(TWINSPAN),and by using the indices of richness,species diversity,and evenness,this paper studied the species diversity of the forest communities within the Reserve,and by using Spearman’s rank correlation coefficient,analyzed the relationships among the species diversity in the tree,shrub,and herbaceous layers of the communities.The richness,species diversity,and evenness indices of the 15 associations of the communities well reflected the diversity differences of all the associations.Overall,the richness and species diversity indices of most associations presented the sequence of herbaceous layer shrub layer tree layer,and the evenness index was the lowest in herb layer but had less difference in tree and shrub layers.There existed significant differences(P 0.01) among the Patrick index,Simpson index,and Shannon index and between the Pielou index and Alatalo index.In Ass.3(Larix principis-rupprechtii-Spiraea pubescens +Rosa bella-Fragaria orientalis),there was a significant negative correlation(r =-0.643,P0.05) between shrub and herbaceous layers;in Ass.8(Betula platyphylla+Populus davidiana-Cotoneaster acutifolius+R.bella-Carex stenophylloides),shrub layer had a significant negative correlation(r =-0.458,P0.05) with tree layer but a significant positive correlation(r = 0.404,P 0.05) with herbaceous layer;in Ass.11(Picea meyeri-C.stenophylloides+Carpesium cernuum),tree layer was significantly negatively correlated with herbaceous layer(r =-0.949,P0.05).