Abstract
Leaf morphology is one of the important indicators for studying the response of plants to climate change. Gymnosperms play a crucial role in maintaining biodiversity and ecosystem stability in China. However, the geographical and altitudinal distribution patterns of gymnosperms with different leaf morphologies in China in response to climate change are not yet fully understood. This study utilized occurrence data for 71 rare gymnosperm species (including varieties) and 15 environmental variables to model the contemporary geographical distribution for the 2070s and the 2090s under two shared socioeconomic pathway scenarios (SSP2-4.5 and SSP5-8.5). Gymnosperm species were classified into five groups based on their leaf shapes (needle-shaped, scale-shaped, lanceolate-shaped, fan-shaped, and strip-shaped), and the analysis revealed that the primary climatic variable driving ecological niche differences among these groups was Bio15 (precipitation seasonality). Lanceolate-leaved gymnosperms exhibited an expansionary trend, whereas other groups generally showed range reductions under future climatic scenarios. The results indicated that approximately half of the gymnosperm species will experience notable range contractions and gradual migration to higher altitudes in northwestern regions from the present to the 2090s. Hotspots for species richness were identified in the eastern Yunnan-Guizhou Plateau, the Nanling Mountains, and the eastern Zhejiang-Fujian Hills. However, these hotspots showed limited overlap with existing nature reserves in China. The threat status of some species will be severely upgraded from vulnerable to critically endangered, such as Abies recurvata, highlighting the urgent need for enhanced conservation efforts. This study enhances understanding of the future distribution patterns of China's gymnosperms and provides valuable insights for developing targeted protection and conservation strategies.