长江上游玉龙雪山植物物种多样性形成的探讨

玉龙雪山位于云南省西北部的丽江市，是界于澜沧江和金沙江之间云岭山脉的主峰。南临丽江坝，东、西、北三面均为金沙江环绕,处于中国三大植物多样性中心之一的横断山区的核心地带，具有很高的植物物种多样性。该区有藻类植物31科72属196种，地衣植物17科20余种，在苔藓植物中有苔类45种、藓类130种，蕨类植物约有220 多种，种子植物有171科804属2 646种(不含栽培种及种下等级)，其中中国特有种1 631种，占本区种子植物总数的61.46%。对玉龙雪山植物物种多样性的形成进行了探讨，认为玉龙雪山丰富的植物物种多样性主要来源于3个第三纪古植物区系成分即古北大陆、古地中海以及古南大陆成分,其中以古北大陆成分为主。之后的新构造运动及第四纪冰期冰川的反复作用，形成了玉龙雪山复杂多样的生态环境。来源于以上3个古植物区系成分的植物物种在以后的进化过程中经过不断分化、发展以及与临近区域的交流，形成了现在丰富的植物物种多样性格局。

ANALYSIS ON THE FORMATION OF PLANT SPECIES DIVERSITY IN THE YULONG MOUNTAINS,UPPER REACHES OF YANGTZE RIVER

The Yulong Mountains located in Lijiang , northwest of Yunnan, is the highest peak in Yun ling Mountains range of Hengduan Mountains system. It is encircled by Jinsha River （the upper reaches of Yangtze River） from east, west and north . As one of the three plant diversity centers of plant species in China and according to preliminary statistics, there are about 196 species of algae (belonging to 72 genera and 31 families), 20 species of lichens (belonging to 17 families), 45 species of liverwort and 130 species of moss, 220 species of fern, 2 646 species of seed plant (representing 804 genera and 171 families). Among these seed plant, 1 631 species are endemic in China, there is about 61.64% of the total seed plants in this small area. The formation of plant species diversity in this region is discussed in this paper. Through paleobotanical data and paleogeologic analysis, it is considered that the richness of plant species diversity in this region is originated from three Tertiary flora——Arctic tertiary flora, Tethyan Tertiary flora and Boreotropical flora. with the elements of Arctic Tertiary flora having a most important place. Then under the repeating effects of Neotectonic movement and Quaternary glaciations, for the various climate and environment, these flora further developing, differentiation and evolution in this region, and exchanged with neighboring regional flora, formed the richness of plant species diversity in this area.