Abstract:

Species diversity of plant communities in Baotianman was studied in this paper.Distribution trends of species richness indices,species diversity indices and species evenness indices along the community gradient were almost the same.They reflected the different species composition of different plant communities.Species richness indices of herb layer were higher than that of both tree and shrub layer,and its variations along the community gradient were higher than that of shurb layer,while shrub layer were higher than of tree layer.Species diversity indices of tree layer were lower than that of shrub and herb layer,variations of shrub layer along the community gradient were lower than that of both herb and tree layer obviously.Species evenness indices of shrub layer were higher than that of both tree and herb layer,and its variations along the community gradient were lower than that of both tree and herb layer.Species richness indices and diversity indices of the plant communities that distribute at both high and low altitude were higher than the plant communities at middle altitude.The plant communities at middle altitude had lower species evenness indices mostly,but higher values occurred in the plant communites at all altitude.The higher species richness indices and diversity indices of herb layer occurred at low altitude,the lower occurred at middle altitude.The patterns of all kinds of indices of tree and shrub layer and species evenness indices of herb layer along altitude gradient were variable.

Key words: Plant community, Species diversity, Community gradient, Altitude gradient, Baotianman