Abstract: This paper presented the investigation and analysis on the species diversity of shrub layer and herb layer in the main forest landscape types in West Dongting Lake.Comprehensive evaluation method and entropy weight method are combined to get the comprehensive indexes of species diversity,and the comprehensive level of species diversity in different forest landscapes was measured.According to the weight value of each index,the main factors affecting the level of species diversity in the study area were found out.The results show that the Simpson indexes of herb layer were 0.793 0~0.916 1.The Shannon-Wiener indexes of herb layer were 1.759 6~2.717 6.The young Chinese fir forest landscape is the highest and the bamboo forest landscape is the lowest.The Simpson indexes of shrub layer were 0.794 2~0.927 7.The Shannon-Wiener indexes of shrub layer were 1.869 9~2.909 0.The broad leaved forest landscape is the highest and the bamboo forest landscape is the lowest。The species diversity index of shrub layer was higher than that of the herb layer as a whole.The comprehensive index of species diversity in different forest landscapes was 0.012 3~0.829 4。The broad leaved forest landscape is the highest and the bamboo forest landscape is the lowest.The low level of species richness and evenness of herb layer was the main factors influencing the level of species diversity of different forest landscapes in the study area,such as bamboo forest,shrub forest,and so on.

Key words: West DongtingLake, forest landscape, species diversity, composite index