A comprehensive study published on December 19, 2025, in *Science Advances* reveals how mountain building and climate change have significantly influenced alpine biodiversity over the past 30 million years. Researchers from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences, in collaboration with international institutions, conducted a detailed analysis of five major mountain systems in the Northern Hemisphere, uncovering critical insights into the evolution of plant species in these regions.
This research addresses a longstanding question regarding the processes that have shaped the rich plant diversity found in alpine environments. By integrating phylogenetic analyses with geological contexts and paleoclimate reconstructions, the team examined the evolutionary history of 34 groups of flowering plants, encompassing a total of 8,456 species. Their findings highlight the interconnectedness of geological and climatic changes in the development of alpine floras.
Key Findings on Plant Evolution
According to Xing Yaowu, a 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 are closely tied to both mountain uplift and global cooling, regardless of the origins of these groups.
Mountain ranges, through the process of uplift, created novel habitats for plants to evolve into new species. Concurrently, cooler climates facilitated the connection of previously isolated high-altitude regions, allowing for the dispersal and mixing of plant species across diverse mountain ranges. The researchers also discovered that evolutionary mechanisms varied among mountain systems. For instance, the Tibeto-Himalayan-Hengduan (THH) region functioned as a “cradle” for biodiversity, with over half of new species emerging through in-situ diversification. In contrast, European and Irano-Turanian alpine floras primarily derived from local mid- to low-elevation lineages adapting to alpine habitats, while the Tianshan Mountains predominantly imported species from the THH region.
Implications for Global Biodiversity
The study’s first author, Ding Wenna, emphasized that these asynchronous yet predictable dynamics of species assembly help explain the significant regional differences in alpine plant communities today. After millions of years of diversification, the researchers noted that global cooling intensified the connections between cold Arctic and alpine habitats, transforming the boreal-arctic region into a “biogeographic crossroads” for flora exchange between Eurasia and North America.
Together, these findings contribute to a more coherent understanding of why mountain regions support exceptionally high biodiversity. The research offers crucial insights into the complex interactions between geological processes and climatic changes, which have shaped the plant life in these unique ecosystems over millions of years. The study is documented in detail in the article titled “The asynchronous rise of Northern Hemisphere alpine floras reveals general responses of biotic assembly to orogeny and climate change,” published in *Science Advances*.
For more information, readers can access the full study through the DOI: 10.1126/sciadv.adz1888.