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bioRxiv · 10.64898/2026.10.12.758598

Borealization: a biodiversity refugium and evolutionary cradle during the Permian-Triassic climate crisis

Shatwell, A.·Foster, W. J.
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Abstract

Understanding how organisms track suitable environments during rapid climate change is constrained by the brevity of modern observations. Using the fossil record, we identify the mid- to high-latitude Boreal Ocean as a regional biodiversity refugium during the Permian-Triassic climate crisis. Additional Boreal successions indicate sustained diversity and comparatively hospitable conditions. Biogeographic reconstructions reveal that 30% of Sassendalen taxa survived the extinction event, with two-thirds expanding or shifting their latitudinal ranges into the Boreal Ocean. More than 90% of newly evolved species originated there, and their lineages subsequently dispersed at differing rates into other regions throughout the Early Triassic. These findings identify poleward migration and high-latitude refugia as key drivers of biodiversity persistence and evolutionary recovery during climate crises.

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Shatwell, A., Foster, W. J.. 2026-10-16. Borealization: a biodiversity refugium and evolutionary cradle during the Permian-Triassic climate crisis. https://doi.org/10.64898/2026.10.12.758598

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