太白山高山林线植被的数量分析

QUANTITATIVE ANALYSIS OF THE VEGETATION NEAR THE ALPINE TIMBERLINE OF TAIBAI MOUNTAIN

通过对太白山南坡高山林线（ａｌｐｉｎｅｔｉｍｂｅｒｌｉｎｅ） 及其附近的草本植物群落的聚类、排序、物种多样性以及生态种组等研究分析表明：１ ．太白山高山植物群落的物种多样性随着海拔高度的升高而增加；２ ．群落交错带（ｅｃｏｔｏｎｅ） 的物种多样性要比相邻群落内部高；３ ．在太白山高山带，随着海拔升高，种一面积相关值呈波动增加。

As an ecotone between the closed forest and the alpine meadow,the alpine tinbeline is regarded as sensitive to climate change and human interference.It is now one of the important aspects in the global change research.As an ecotone between the temperate zone and the subtropical zone as well as the highest mountain of East China,the Taibai Mountain,the peak of Qinling Range,is located in the sensitive regions to climate change in China.For identifying the vegetation boundaries at the high altitude in Taibai Mountain,and for the future study of the alpine timberline response to the climate change,the herbaceous species in the communities are quantitatively analyzed. By using community ordination,classification and analysis of plant species diversity of the vegetation striding the timberline of Taibai Mountain,following conclusions can be drawn: 1.The whole tendency of the plant species diversity increases with the ascent of the altitude.But there exists a wave:the diversities of the ecotones are higher than those of the adjacent communities; 2.The slope of the curve between species and logarithmic area is higher in the adjacent communities than that in the ecotones; 3.The upper limit of the closed forest is about 3 400 m while the treeline is about 3 500 m .Therefore the timberline transitional zone is located at the altiude between 3 400 m and 3 500 m.As for the ecotone between the sub-alpine shrub meadow and the alpine meadow (tree species line),it is situated between the altitude of 3 600 m and 3 700 m.