Distribution patterns of three Pyrus species under climate change in China based on ensemble modeling

Climate change is profoundly affecting global ecosystems and biodiversity, with fruit trees being one of the plant groups relatively sensitive to climate change. China is one of the centers of diversity for the genus Pyrus, harboring abundant wild and cultivated germplasm resources. However, systematic assessments of the responses of Pyrus species to future climate change at the national scale in China using species distribution modelling remain limited. In this study, we compiled 153 occurrence records of Pyrus betulifolia, 47 of Pyrus pyrifolia, and 117 of Pyrus ussuriensis, and integrated climatic, soil, topographic, and anthropogenic variables. A biomod2-based ensemble modelling framework was used to predict potential suitable habitats under current and future climate scenarios and to identify key environmental drivers. The results showed that temperature seasonality (Bio4) was the dominant factor influencing the distributions of P. betulifolia and P. ussuriensis, whereas precipitation of the warmest quarter (Bio18) was the primary driver of P. pyrifolia. Under current climatic conditions, highly suitable habitats accounted for 4.04%, 10.93%, and 13.07% of China's land area for the three species, respectively. Under future climate scenarios, the suitable distributions of P. betulifolia and P. pyrifolia shift northward, whereas the suitable distribution of P. ussuriensis shifts westward. Meanwhile, the suitable habitat areas of all three species are projected to expand to varying degrees.