宝兴陆栖脊椎动物区系的垂直分化及其原因的探讨

宝兴的91.13％陆生脊椎动物为恒温动物。鸟类季节相与我国东部南北均不相同,川滇及喜马拉雅山地的区系成分多达30.5％.根据其各植被带夏季的陆栖脊椎动物区系的相似率将分别为3个垂直带.探讨各垂直带的动物区系的现状和起源演变后认为:当地阔叶林带的动物区系的历史和现状与长江中下游地区大致相同;其余则受新构造运动和更新世冰川进退影响较大;生物进化过程的加快使之川滇喜马拉雅山区可能成为某些分类群的次级分布中心.

AN EXPLORATION ON THE VERTICAL DIFFERENTIATION OF TETRAPOD FAUNA AND ITS CAUSE IN BOAXING COUNTY, SICHUAN

So far 372 species of tetrapod have been known from Boaxing (formerly named Muping) county.On the ground of breeding region of 331 species, a classifiction of faunal composition has been made. The results indicate that the oriental species are 38.67% of the total, the species of Sichuan-Yunnan-Himalaya Mountains are 30.51%, and only 19.33% to the Palaca-rctic in this county. The fannal composition is different among 5 vegetations of various altitudes in summer. Using the clustering method, we divided this mountainous area into three vertical zones. Then, the composition of the fauna of each zone was staled, and the crigin and development relating to the faura of those zones were analysed.In basal zone, the ancient species are more abundant, and the faura, so far as the developmental history and situation, bears a resemblance to the medium and lower Yangtse Rever valley. In contrast, the endemics belonging to the Sichuan-Yunnan-Himalaya Mountains are more abundant in intermediate zone. Many endemics as above originated from the oriental taxa at first appearance, but it is a distinct difference between the ancestor and the descentant because the latter adapted itself highly to the cold and damp environment.In addition, we realize that the region of Sichuan-Yunnan-Himalaya Mountains may be the secondary centre of distribution of some taxa. Such centre seems to result from the acca-lerament of evolution as a consequence of the great change and complexity of environment in part of the ranges of those taxa.