白水江自然保护区植被区系特征分析

The Analysis of Flora Characteristics Baishuijiang Natural Sanctuary in Gansu

分析了白水江自然保护区植被区系特征．其结果是：该区系具明显的温带性质；起源古老，具有第三纪亚热带亚高山森林植物区系在第四纪冰期前的历史联系及冰期后的分化特征；地理成分复杂，替代过渡现象明显．同时用主成分分析（Ｐ．Ｃ．Ａ．）和信息聚类分析（Ｉ．Ｃ．Ａ．）方法对本区系与国内其它１３个具有代表性地区的种子植物区系进行了比较分析，将１４个地区可分为５组．实践证明。

The flora characteristics of Baishuijiang natural sanctuary are discussed. principal components analysis(P.C.A.) and information cluster analysis(I.C.A.). They are comparatively studied between the flora of this area and those of other 3 floristics. The results show:The seedplant species are comparatively rich. There are 1 810 species in the area, which belong to 813 genera and 136 families; Among the areal types of Chinese genera of flora plants, there are 15 types and 22 subtypes in the area, the types of temperate zone account for more than twothirds; The geographical elements of the area are very complex, the transition and replacement are obvious; Its flora originated from Tertiary ancient subtropic, subalp forest, which was historically connected with the preice age and the differentiated traits of postice age in the Quaterary; With P.C.A. and I.C.A. 14 representative florestics can be divided into 5 groups. It is proved that the analysis can objectively reflect the similarities and differences of the flora.