高黎贡山北段东西坡种子植物区系的比较研究

A Comparative Floristic Study on the Seed Plants of the East Side and the West Side of the Northern Gaoligong Mts.in Northwestern Yunnan,China

高黎贡山北段的东西坡由于在降雨量和热量分配等方面存在着显著的差异,致使东西坡在植物的种类、组成及区系特征等方面表现出明显的差异。东坡记载野生种子植物152科,580属,1475种及192变种(亚种),西坡记载野生种子植物162科,659属,1804种及186变种(亚种)。东西坡种子植物科、属、种的对比分析表明:1)东西坡现代种子植物区系具有相同的历史渊源,但其区系联系减弱了,东西坡区系相似性程度,依科、属、种的顺序依次递减;2)西坡现代种子植物区系比东坡具有更为深刻的热带起源烙印。就科、属、种三个水平来说,东坡的热带成分低于西坡,温带成分高于西坡。许多典型的泛热带大科在西坡比东坡有着更为丰富的种类,其中有些泛热带科分子在东坡缺乏分布,而在西坡找到了合适的驻留之地;3)西坡现代种子植物区系与东喜马拉雅植物区系的联系比东坡紧密,而东坡与高黎贡山以东的区系联系比西坡密切,由于高黎贡山山脉的阻隔,近代植物物种的东西坡交流发生了障碍;4)西坡生态地理环境比东坡更有利于物种的生存、繁衍和分化,它既是古老成分的避难所,又是孕育新生成分的摇篮。

The differences in rainfall and temperature between the east and west sides of the northern Gaoligong Mts. leads to distinct differences in the plant diversity and floristic characteristics between the two sides. Recorded taxa on the east side include 1 475 native species and 192 varieties （or subspecies） belonging to 580 genera in 152 families and for the west side include 1 804 native species and 186 varieties （or subspecies） belonging to 659 gencra in 162 families. Based on the statistics and analysis of famihes, genera, and species, a comparative floristic study on the seed plants for the east side and the west side of the northern Gaoligeng Mts. was carried out. The results are as follows： 1） The present flora on the east and west sides of the northern Gaoligeng Mts. have the same floristic origins, but the relative contribution from these different sources has changed through time. The result is that the floristic similarity of families, genera, and species between the east side and the west side has decreased through time; 2） The floristic characteristic of seed plants for the west side has become more greatly influenced by tropical floristic elements than has that of the east side, and the influence by the temperate floristic elements has become less influenced on the west side but greater on the east side; 3） The flora of the west side is more closely linked with that of the eastern Himalayans than is the flora of the east side, and the tlora of the east side is more closely linked with the other floras farther to the east. Owing to the obstruct of the Gaoligong Mts. ridge itself, it is seemingly difficnlt for the species interchange between the two sides of the nots.hem Gaohgong Mts. ; 4） The ecological-geographical environment has made it more conducive to species conservation and the speciafion on the west side than on the east side, so the west side is not only a refuge for some ancient floristic elements but also as a cradle of some new species.