Science ( IF 41.845 ) Pub Date : 2020-07-31 , DOI: 10.1126/science.abb4484 Wen-Na Ding, Richard H. Ree, Robert A. Spicer, Yao-Wu Xing
Understanding how alpine biotas formed in response to historical environmental change may improve our ability to predict and mitigate the threats to alpine species posed by global warming. In the world’s richest temperate alpine ﬂora, that of the Tibet-Himalaya-Hengduan region, phylogenetic reconstructions of biome and geographic range evolution show that extant lineages emerged by the early Oligocene and diversiﬁed ﬁrst in the Hengduan Mountains. By the early to middle Miocene, accelerated diversiﬁcation and colonization of adjacent regions were likely driven jointly by mountain building and intensiﬁcation of the Asian monsoon. The alpine ﬂora of the Hengduan Mountains has continuously existed far longer than any other alpine flora on Earth and illustrates how modern biotas have been shaped by past geological and climatic events.