Study on Species Diversity during the Succession of Plant Communities on Abandoned Farmlands in Guancen Mountains,Shanxi

The successive processes of plant communities were studied on abandoned farmlands in Guancen Mountain of Shanxi Province.Seven groups were divided by using TWINSPAN,representing seven associations and belonging to three vegetation succession stages separately—herbaceous communities stage,shrub communities stage and forest communities stage.The change regularity of the species richness,evenness,diversity and dominance were analyzed by using species diversity index.The results showed that the species richness and diversity were increasing,dominance and evenness were reducing with the succession time extending.The change regularity of composition,structure and life type of plant communities were analyzed by using DCA ordination.The results showed that the changes of plant communities were rapidness with environmental alteration during succession on abandoned farmlands and the forest community of Larix principis-rupprechtii turning into constructive species were formed in this area.It illustrated further that the richer species composition was,the higher species diversity was.The relationship of species diversity,elevation and abandoned time was analyzed further by using DCA,the conclusion was same with the foregoing tendency — species richness and diversity were increasing,dominance and evenness were reducing with elevation rising and the succession time extending.