北温带水青冈属的间断分布及其泛生物地理学解释

水青冈属(Fagus L.)在北温带呈间断分布, 已发现的丰富的第三纪化石为讨论其起源和演化提供了证据。该文采用泛生物地理学的轨迹分析方法对水青冈属的分布进行了研究, 试图分析水青冈属的分布格局, 进而讨论其进化问题。结果表明, 水青冈属在中国、日本、北美、欧洲的分布是完全间断的, 没有一个共有轨迹连接它们, 即使在毗邻的、且有植物亲缘关系的中国和日本, 也没有一个共有轨迹连接。完全间断的轨迹对分析水青冈属的起源、演化和扩散学说, 没有提供任何信息。仅有两条共有轨迹分别分布在中国东南部和日本, 分别代表了中国4种和日本3种水青冈属种类的连接, 说明水青冈属经历了漫长的历史演化, 扩散能力是有局限性的, 仅在分化和多样性中心进行了一些分化和演化, 整个属并未进行长距离的扩散, 或者长距离扩散早已销声匿迹了, 现代的分布格局完全是以间断为最主要特征的。间断分布的动力解释为古地中海西撤、青藏高原隆起、东亚季风活动等地质历史事件, 第三纪以来特别是第四纪冰期活动等气候波动, 以及水青冈属植物的生物学特性(特别是喜温喜湿)。

A panbiogeographical explanation of the disjunct distribution of Fagus(Fagaceae) in the northern temperate zone

Aims Fagus L.has a disjunct distribution in the northern temperate zone,and there is a rich collection of Tertiary fossils from East Asia,Europe and North America.A panbiogeographical analysis of Fagus was undertaken to analyze the distribution pattern and evolution of the genus.Methods Distribution data of 581 records of 10 species were obtained from herbaria and monographs.Track analysis of panbiogeography and software MartiTrack were used for data analysis.Important findings Results indicated that there was no generalized track linking the distributions among China,Japan,Europe and North America or even between China and Japan,two adjacent areas in East Asia.Two regional generalized tracks were only found within China and Japan.These facts imply that the Fagus distribution cannot be explained by dispersal.Dispersal probably only occurred in limited and/or local regions and not as dispersal across the northern temperate zone in the Tertiary.The disjunction most likely resulted from(1) geological historical events such as Tethys westward movement,Qinghai-Tibet Plateau uplift,and Asian monsoon action,(2) climate change since the Tertiary,especially climate fluctuation during Quaternary glaciation,and(3) Fagus biological characteristics with regard to humid and temperate climate and annual rainfall.