KUNMING, Dec. 20 (Xinhua) -- A newly published study in the scientific journal Science Advances unveils the deep-time processes responsible for the exceptional plant diversity characterizing the world's mountain regions.
While the richness of alpine flora is well-documented, this research, spearheaded by scientists from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences, offers a comprehensive analysis of how geological forces and climate change have shaped this biodiversity over millions of years.
The study combined evolutionary biology with geological and paleoclimate data to trace the history of alpine plants across five major mountain systems in the Northern Hemisphere.
Focusing on 34 groups of flowering plants encompassing 8,456 species, the researchers reconstructed when and where these plants spread and diversified.
The findings demonstrate that the expansion and diversification of alpine plant groups relied consistently on two interconnected factors: mountain uplift and global cooling. The rise of mountains created new high-altitude habitats where plants could evolve into new species. At the same time, cooling climates expanded cold environments, effectively connecting once-separate mountain ranges and allowing plants to disperse and mix across vast distances over millions of years.
"We linked plant evolution with Earth's geological and climate history, revealing how ancient mountains and climate changes have shaped alpine life in clear, predictable ways," said Xing Yaowu of XTBG, co-corresponding author of the study.
The research also identified distinct evolutionary mechanisms across different mountain systems. The Tibeto-Himalayan-Hengduan (THH) region functioned as a "cradle," with over half of its new species originating from local diversification. In contrast, European and Irano-Turanian alpine floras were primarily assembled from local mid- to low-elevation lineages that adapted to higher elevations. Meanwhile, the Tianshan Mountains largely "imported" species from the THH region.
Across all areas, active mountain uplift was found to consistently accelerate the formation of new plant species. "It helps explain why alpine plant communities vary so much from one region to another today," said Ding Wenna from XTBG, first author of the study.
The study provides crucial scientific evidence for understanding global biodiversity patterns, and establishes a clear framework explaining why mountain regions support an exceptionally high proportion of the world's plant species, Ding said. ■
