Spec ies Composition and D iversity in the Process of Na tura l Succession of KarstVegeta tion in Centra l Guizhou: Ca se Study of Pud ing Coun try in Gu izhou

The p rocess of natural succession of vegetation in Karst rocky desertification area in central Guizhou wasdivided into the herbosa stage, the stage of herbosa-shrub, the stage of vine-shrub, the stage of subaltern tree forestand the stage of evergreen broad-leaved forest according to the characteristic of p lant community. The speciesdiversities in the layers of herb, shrub, tree and community at different successional stages were measured by themethods of species abundance, Simp son index, Shannon-Wiener index and Pielou’s evenness index. The resultsshowed that the diversity indices in herb layer rose steadily after the succession developed from the herbosa stage,and reached the maximum in the stage of vine-shrub, then decreased gradually. The diversity indices in shrub layer, tree layer and community reached the maximum in the stage of subaltern tree forest. The diversity indices ofherb layer were higher than those of shrub layer in the herbosa stage and the stage of herbosa-shrub. There weredifference among the indices of the herb and shrub layers in the stage of vine-shrub, and the indices of tree layerwere the lowest. While in the stage of subaltern tree forest and climax stage, diversity indices of shrub layer werehigher than those of herb layer, which was greater than those of tree layer. In the case of litter artificial disturbingeffect, the advantage of herbage declined while that of shrub and arbor rose steadily in the natural succession ofvegetation in Karst rocky desertification area in central Guizhou. And the Karst forest formed finally.