Ancient orogenic and monsoon-driven assembly of the world’s richest temperate alpine flora

• Published in: Science (American Association for the Advancement of Science) Vol. 369; no. 6503; pp. 578 - 581
• Main Authors: Ding, Wen-Na, Ree, Richard H., Spicer, Robert A., Xing, Yao-Wu
• Format: Journal Article
• Language: English
• Published: Washington The American Association for the Advancement of Science 31.07.2020
• Subjects: Alpine environments; Alpine regions; Climate change; Colonization; Environmental changes; Evolution; Flora; Global warming; Miocene; Monsoons; Mountains; Oligocene; Orogeny; Phylogeny; Species; Tectonics; Wind; Hengduan Mountains; Tibet
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.abb4484

Origins of an alpine flora The evolution of high mountain floras is strongly influenced by tectonic and climatic history. Ding et al. document the timing, tempo, and mode by which the world's most species-rich alpine flora, that of the Tibet-Himalaya-Hengduan region, was assembled. Alpine assemblages in the region are older than previously thought, with lineages tracing their alpine ancestry to the early Oligocene—older than any other modern alpine system. Alpine species diversified faster during periods of orogeny and intensification of the Asian monsoon, and the Hengduan Mountains—the most species-rich area in this region—played a key biogeographic role as the location of the earliest pulse of alpine diversification in the Oligocene. Science , this issue p. 578 Mountain formation and monsoon intensification drove species accumulation in the alpine flora of the Tibet-Himalaya-Hengduan region. 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.