Researchers from the Chinese Academy of Sciences, in collaboration with international institutions, have uncovered significant insights into how mountain building and climate change over the last 30 million years have influenced alpine biodiversity. Their findings, published in the journal Science Advances on December 19, 2025, highlight the critical roles of geological and climatic processes in shaping plant diversity within mountain ecosystems across the Northern Hemisphere.
The study focused on five major mountain systems and examined the evolutionary history of 34 groups of flowering plants, encompassing a total of 8,456 species. By integrating phylogenetic analyses with geological context and paleoclimate reconstructions, the researchers were able to determine how mountain uplift and climatic cooling contributed to the development of diverse alpine floras.
Key Findings on Plant Evolution
According to Xing Yaowu, co-corresponding author of the study at the Xishuangbanna Tropical Botanical Garden (XTBG), “Our work links plant evolution with Earth’s geological and climate history.” The study reveals that both the uplift of mountains and cooler global temperatures have been vital for the expansion and diversification of alpine plant groups, irrespective of their origins.
For instance, the formation of new habitats through rising mountains provided opportunities for plants to evolve into distinct species. Meanwhile, the cooling climate connected previously isolated high-altitude regions, facilitating the dispersal and mixing of plant species across different mountain ranges.
The research also identified varying evolutionary mechanisms across different mountain systems. In the Tibeto-Himalayan-Hengduan (THH) region, over half of new species emerged through in-situ diversification, acting as a “cradle” for plant evolution. Conversely, European and Irano-Turanian alpine floras primarily formed from adaptations of local mid- to low-elevation lineages. The Tianshan Mountains were found to import many species from the THH region, showcasing another layer of complexity in plant migration and evolution.
Implications for Global Biodiversity
The study emphasizes how distinct assembly dynamics contribute to the differences observed in alpine plant communities across regions. Ding Wenna, the first author of the study, noted that “these asynchronous yet predictable assembly dynamics help explain why alpine plant communities differ so much from one region to another today.”
Over the last five million years, global cooling has intensified connections between cold Arctic and alpine habitats, transforming the boreal-arctic region into a “biogeographic crossroads.” This has allowed for significant floristic exchanges between Eurasia and North America.
The research provides a coherent understanding of why mountain regions support such extraordinarily high biodiversity. These findings not only advance our knowledge of plant evolution but also underscore the importance of geological and climatic factors in shaping the natural world.
More information on this study can be found in the article titled “The asynchronous rise of Northern Hemisphere alpine floras reveals general responses of biotic assembly to orogeny and climate change,” in Science Advances. The article can be accessed at DOI: 10.1126/sciadv.adz1888.
