Summary:
Mountain building and long-term climate cooling have played a central role in shaping alpine plant diversity across the Northern Hemisphere, according to a new study published in Science Advances. By tracing how plants responded to geological and climatic change over the past 30 million years, researchers provide one of the most detailed reconstructions to date of how mountain biodiversity formed.
The international team analysed the evolutionary history of 34 flowering plant groups, representing 8,456 species, across five major mountain systems. Combining phylogenetic data with geological records and palaeoclimate reconstructions, they tracked how tectonic uplift created new high-altitude habitats while progressive global cooling expanded cold environments. These changes altered how alpine regions were connected, allowing plants to diversify locally or move between mountain ranges.
The results show that alpine floras emerged at different times and through different processes, but followed shared biological responses to mountain uplift and climate change. Over the past five million years, increased links between Arctic and alpine habitats also turned northern regions into major corridors for plant exchange.
Researchers show impact of mountain building and climate change on alpine biodiversity
In a study published in Science Advances, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences, along with collaborators from international institutions, explored the impact of mountain building and climate cooling over 30 million years across five major mountain systems in the Northern Hemisphere and revealed that these processes are key drivers of the rich plant diversity found in the Earth’s alpine biome.
Mountain regions harbor a disproportional share of the world’s plant species, but the processes responsible for assembling this diversity over deep time have remained unclear. To address this question, the researchers combined phylogenetic analyses with geological context and paleoclimate reconstructions, allowing them to identify the roles of mountain building and climate change in the evolutionary assembly of alpine floras.
They examined the evolutionary history of 34 groups of flowering plants, covering 8,456 species. They reconstructed when and where these plants spread and diversified across different mountain ranges. Using paleoclimate reconstructions, they subsequently mapped how progressive climate cooling expanded cold habitats, thereby connecting once-separate high-altitude regions over millions of years.
According to XING Yaowu of XTBG, co-corresponding author of the study: “Our work links plant evolution with the Earth’s geological and climate history, showing how ancient mountains and climate changes have shaped alpine life in clear, predictable ways.”
Specifically, the results indicate that the expansion and diversification of alpine plant groups relied on both mountain uplift and cooler global temperatures regardless of where or when these groups originated. For example, rising mountains created new habitats where plants could evolve into new species, while cooling climates connected once-isolated mountain areas, enabling plants to disperse and mix across mountain ranges.
At the same time, the researchers found that different mountain systems exhibited distinct evolutionary mechanisms. For example, the Tibeto-Himalayan-Hengduan (THH) region acted as a “cradle” – with over half of new species arising from in situ diversification, while European and Irano-Turanian alpine floras were assembled mainly from local mid- to low-elevation lineages that adapted to alpine habitats. In contrast, the Tianshan Mountains largely “imported” species from the THH region.
Across all regions, active mountain uplift was found to consistently accelerate the formation of new plant species within the same area, highlighting the role of geological processes in shaping biodiversity.
“These asynchronous yet predictable assembly dynamics help explain why alpine plant communities differ so much from one region to another today,” said DING Wenna from XTBG, first author of the study.
After eons of alpine plant diversification, global cooling intensified connections between cold Arctic and alpine habitats over the last five million years, according to the researchers, turning the boreal-arctic region into a “biogeographic crossroads” for floristic exchange between Eurasia and North America. Together, these findings provide a coherent explanation for why mountain regions support exceptionally high biodiversity.
Journal Reference:
Wenna Ding, Richard H. Ree, Michael R. May, Philipp Brun, Oskar Hagen, Dirk N. Karger, Alexander Skeels, Loïc Pellissier, Yaowu Xing, and Niklaus E. Zimmermann, ‘The asynchronous rise of Northern Hemisphere alpine floras reveals general responses of biotic assembly to orogeny and climate change’, Science Advances 11, (51): eadz1888 (2025). DOI: 10.1126/sciadv.adz1888
Article Source:
Press Release/Material by Chinese Academy of Sciences (CAS)
Featured image credit: Ding Wenna
