A recent study published on December 19, 2025, in Science Advances, reveals how the processes of mountain building and climate change have significantly influenced the biodiversity of alpine regions over the past 30 million years. Researchers from the Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences, collaborating with international institutions, conducted an extensive examination of five major mountain systems in the Northern Hemisphere.
The research addresses a crucial question: how do alpine regions, which host a remarkable variety of plant species, come to possess such rich biodiversity? The team combined phylogenetic analyses with geological context and paleoclimate reconstructions to elucidate the roles of mountain formation and climatic shifts in the evolutionary development of alpine floras.
The study focused on the evolutionary history of 34 groups of flowering plants, encompassing 8,456 species. The researchers traced the dispersal and diversification of these plants across various mountain ranges, mapping how climate cooling gradually expanded cold habitats. This expansion connected previously isolated high-altitude regions over millions of years.
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 findings indicate that the expansion and diversification of alpine plant groups relied on both mountain uplift and cooler global temperatures, regardless of their origin.
Specifically, rising mountains created new habitats conducive to plant evolution, while cooling climates facilitated the mixing of flora across mountain ranges. Distinct evolutionary mechanisms emerged across different mountain systems. The Tibeto-Himalayan-Hengduan (THH) region served as a “cradle” for biodiversity, with over half of new species arising from in-situ diversification. In contrast, European and Irano-Turanian alpine floras primarily evolved from local mid- to low-elevation lineages adapting to alpine conditions. Meanwhile, the Tianshan Mountains predominantly “imported” species from the THH region.
Across all examined regions, active mountain uplift consistently accelerated the formation of new plant species, underscoring the significant influence of geological processes on biodiversity.
Implications for Global Biodiversity
The study highlights the asynchronous yet predictable dynamics of plant community assembly, offering insights into why alpine flora varies significantly from one region to another. Ding Wenna, the study’s first author, noted that after extensive periods of diversification, global cooling intensified connections between cold Arctic and alpine habitats during the last five million years. This transformation established the boreal-arctic region as a “biogeographic crossroads” for floristic exchange between Eurasia and North America.
These findings provide a coherent framework explaining the exceptionally high biodiversity observed in mountain regions. The research not only enhances our understanding of alpine ecosystems but also emphasizes the interplay between geological and climatic factors in shaping the natural world.
For additional information, refer to Wen-Na Ding et al’s study titled, “The asynchronous rise of Northern Hemisphere alpine floras reveals general responses of biotic assembly to orogeny and climate change,” available in Science Advances.
