The LGM refugia of deciduous oak and distribution development since the LGM in China

The distribution development of oak has significant effects on ecosystems and society. Long-term forest distribution studies can help to better understand the vegetation dynamics under climate change or human activities in the future. In this study, we integrated different methods (i.e., palaeoecology, phylogeography, and species distribution models) to investigate the likely locations of glacial refugia and the postglacial development of the main deciduous oak species (i.e., Quercus variabilis, Q. mongolica, Q. dentata, Q. aliena, Q. acutissima and Q. liaotungensis). The results indicated that mountains such as the Changbai, Qinling, and Dabie Mountains acted as the refugia in northern and central China during the Last Glacial Maximum (LGM). The present Quercus in northern China could be the result of local dispersal during the postglacial period rather than only that of long-distance migration from south to north. Climate was the main influencing factor for oak migration, while human activities did not show much influence on this widespread genus. The topography acted as a buffer and made the mountains to act as refugia under a deteriorated climate. Compared with other main tree genera (e.g., Pinus and Betula), the refugia locations and migration routes of deciduous oak species were different because of their physiological differences. The individual migration dynamics of these three genera need to be considered when modelling their dynamics.

Automated summary

This study integrated different methods to investigate the distribution development of main deciduous oak species in China. The results revealed that certain mountains served as refugia during the Last Glacial Maximum, and present oak distribution may be influenced by local dispersal rather than long-distance migration. Climate was identified as the main influencing factor for oak migration, while human activities had limited impact. The study highlights the importance of considering physiological differences and migration dynamics when modeling the dynamics of different tree genera.