A Quantitative Study of Global Paleophytogeography During the Permian-Triassic Transition

The Permian-Triassic transition represents a pivotal episode in Phanerozoic biotic evolution, marked by the most catastrophic mass extinction in Earth's history, which dramatically reshaped terrestrial ecosystems. This study leverages a comprehensive global dataset of 21,585 plant fossil occurrence records (macrofloras and palynomorphs) from the Changhsingian to Induan stages to quantitatively analyze paleophytogeographical dynamics, latitudinal diversity gradients, and ecological responses during this critical interval. By integrating network analysis (Fast-Greedy, Spin-Glass algorithms), multivariate statistics (hCA, NMDS), and the Eco-Plant model, we systematically delineate paleophytogeographical units and reconstruct humidity (EPH) and temperature (EPT) indices. Our findings reveal a pronounced shift from high provincialism in the Changhsingian to post-extinction homogenization in the Induan, driven by the collapse of dispersal barriers and ecological niches. The latitudinal diversity center migrated northward, underscoring the role of mid- to high-latitude regions as climatic refugia during the crisis. Ecological reconstructions highlight a transition from mesophyte- and hygrophyte-dominated assemblages to xerophyte-dominated vegetation, with Central Siberia emerging as a key refugium. Notably, the surge in eurythermic elements during the Induan reflects intensified climatic fluctuations, supporting a “cooling-warming” duality linked to the Siberian Traps volcanism. This study advances our understanding of mass extinction impacts on terrestrial ecosystems, providing a quantitative framework to decipher the interplay between biotic crises, paleoclimate, and phytogeographical reorganization. The results offer critical insights into the resilience and adaptive strategies of plant communities under extreme environmental perturbations, with implications for predicting biodiversity responses to modern climate change.