中国西南地区与台湾种子植物间断分布现象

中国西南地区和台湾植物的间断分布是东亚生物地理学上一个十分有趣的研究课题。该文对种子植物进行了统计,发现有50属具有该分布式样的种对或种（包括变种和亚种）;30属呈台-琼（至粤南）-西南间断分布,而其中大多数类群的分布区在粤南-桂南-滇南,即中国热带线以南。统计结果显示,有41属被子植物在台湾和西南之间呈连续分布;有35属从台湾分布至海南（和/或华南）或至福建（和华南）。中国台湾和大陆之间类群的连续分布,以及两者植物区系的巨大相似性表明,台湾作为大陆性岛屿,与中国大陆曾经属于一个统一的植物区系。新近纪以来台湾中央山脉和中国西南至东喜马拉雅地区均经历了海拔升高的过程,形成相似的低至中、高山生境;在第四纪冰期,一些类群在这两个地区之间形成连续的分布区。后来全球气温升高,这些植物类群从低海拔向高海拔山区迁移,由于华东至华中和华南缺少高山生境,使得原来连续分布的某些类群或其祖先类群在中国西南和台湾两地之间灭绝,从而形成间断分布。同时,台湾与大陆失去陆地连接后造成分类群在台湾和西南地区的隔离分化,以及中国南端热带生境的不连续性导致热带植物属种分布区的破碎也是形成台湾和西南间断分布的重要因素。最后将西南和台湾间断分布类群归纳为3种类型：孑遗型、分化型和热带型。

Disjunct Distribution of Seed Plants Between Southwestern China and Taiwan Island of China

The disjunct distribution of plant taxa from southwestern China to Taiwan is of interest in East Asian biogeographic studies. It has received more attention since the publication of all volumes of the F/ora of Taiwan （the first and second editions, both in English） and Flora Reipublicae Popu/aris Sinicae （in Chinese）. In total, 50 genera of seed plants show disjunct distribution of species pairs or a species （including subspecies and variety） between southwestern China and Taiwan and 30 show disjunct distribution among Taiwan, Hainan island （through southern Guangdong Province） and southwest China. In all, 41 genera of angiosperms show continuous distribution from Taiwan to southwest China and 35 show continuous distribution from Taiwan to Hainan （and/or South China） or to Fujian Province （and South China）. As a continental island, Taiwan had several events of land connection with the Chinese mainland, which resulted in their inte- grated flora. The uplift of both the Central Montane Region of Taiwan and southwest China through the eastern Himalayan region since the Neogene resulted in mountainous habitats from low, to medium and high altitudes in the 2 regions, with similar physical environmental factors. Therefore, some taxa show a distribution continuum from Taiwan to eastern Hi- malaya （or vice versa） during the Quaternary glacial period, when the Taiwan Strait landbridge appeared. Later as the earth became warmer, taxa migrated from low to high altitudes. The disjunct distribution of species between Taiwan and southwest China resulted from the extinction of the taxa in eastern to central and South China, which contain no high mountainous habitats for survival. In addition, the vicariance of taxa after the Taiwan Strait landbridge disappeared and the fragmentation of tropical habitats in the most southern China explain this disjunct distribution. Therefore, the taxa with disjunct distribution were divided into 3 types： survival, vicariant and tropical.