Silurian-Devonian Vegetation Zonation: Integrating Fossil Records and Climate Modeling

We complied the Silurian-Devonian vascular plant macrofossil data and integrated them with paleoclimate simulations from the CESM model. By spatially aligning paleobotanical records and simulated climate variables, a unified paleo-vegetation-climate dataset was constructed. Köppen climate classification criteria were applied to derive key precipitation and temperature thresholds, allowing a preliminary reconstruction of Silurian-Devonian vegetation zonation. The results show that in the Silurian early vascular plants (e.g., Rhyniopsida and Zosterophyllopsida) were mainly distributed in tropical zones, with grassland as the dominant vegetation type. During the Early Devonian, Lycopsida expanded significantly into tropical and subtropical regions, and grassland remained predominant. By the Middle Devonian, Rhyniopsida and Zosterophyllopsida declined, whereas Lycopsida, Cladoxylopsida, and Progymnospermopsida diversified and spread. Vegetation types became more varied, including forests, shrublands, and grasslands. In the Late Devonian, the rise of Spermatopsida marked a key evolutionary event. Lycopsida and Progymnospermopsida forests became established in tropical and subtropical regions, with forests and shrublands dominating the landscape. The quantitative reconstruction of climatic adaptations in Silurian-Devonian vascular plants, combined with paleoclimate modeling, offers new insights into the development of early terrestrial ecosystem and its environmental drivers.