A comprehensive study published on December 19, 2025, in the journal Science Advances, reveals how mountain building and climate change over the past 30 million years have significantly influenced the biodiversity of alpine regions. Researchers from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences, alongside international collaborators, focused on five major mountain systems in the Northern Hemisphere to understand the factors contributing to rich plant diversity in these high-altitude ecosystems.
Mountain regions are known to host a disproportionately high number of plant species. Yet, the specific processes that have led to this remarkable biodiversity remained largely unclear. By employing phylogenetic analyses, geological context, and paleoclimate reconstructions, the researchers were able to shed light on the evolutionary assembly of alpine floras. They examined the evolutionary history of 34 groups of flowering plants, encompassing a total of 8,456 species, to trace their diversification across various mountain ranges.
Key Findings on Plant Evolution
According to Xing Yaowu, co-corresponding author of the study, “Our work links plant evolution with Earth’s geological and climate history, showing how ancient mountains and climate changes have shaped alpine life in clear, predictable ways.” The study indicates that the expansion and diversification of alpine plant groups were influenced by both mountain uplift and cooler global temperatures, regardless of the origin of these groups.
For instance, the rising mountains created new habitats conducive to the evolution of new plant species. Concurrently, cooler climates facilitated the connection of once-isolated mountain areas, allowing for the dispersal and mixing of plant species across different ranges. The research also revealed that distinct mountain systems exhibit unique evolutionary mechanisms. The Tibeto-Himalayan-Hengduan (THH) region, for example, served as a “cradle” for new species, with over half arising from in-situ diversification. In contrast, European and Irano-Turanian alpine floras developed primarily from local mid- to low-elevation lineages adapting to alpine conditions. The Tianshan Mountains, on the other hand, predominantly “imported” species from the THH region.
Implications for Global Biodiversity
The findings reveal important dynamics in how alpine plant communities differ across regions. Ding Wenna, the first author of the study, noted, “These asynchronous yet predictable assembly dynamics help explain why alpine plant communities differ so much from one region to another today.” Over the past five million years, global cooling has intensified connections between cold Arctic and alpine habitats, effectively transforming the boreal-arctic region into a “biogeographic crossroads” for the exchange of plant species between Eurasia and North America.
In summary, this research provides a coherent explanation for the high biodiversity observed in mountain regions. The interplay between geological processes and climate change has created a rich tapestry of alpine flora, underscoring the importance of understanding these dynamics in the context of global biodiversity conservation. The study, conducted by a team of dedicated researchers, continues to illuminate the intricate relationship between Earth’s geological history and the diversity of life it supports.
For more information, refer to the article by Wen-Na Ding et al, titled “The asynchronous rise of Northern Hemisphere alpine floras reveals general responses of biotic assembly to orogeny and climate change,” published in Science Advances. The DOI is 10.1126/sciadv.adz1888.
