Late Quaternary history of Siberian stone pine as revealed by genetic and paleoecological data

Current climatic trends raise concerns about the fate of boreal forests and associated communities. To understand forest vegetation dynamics in the face of future changes, it is necessary to know how trees have responded to past climatic fluctuations. We investigated genetic data and a past distribution based on paleorecords and species distribution modeling data to determine refugia and migration routes of Siberian stone pine ( Pinus sibirica ) from the late Pleistocene to the present. Thus, we gained a deep insight into the past of Siberian stone pine. We revealed four genetic clusters of Siberian stone pine located in the following mountain systems of Siberia: the West Sayan and the Altai (WSA), the East Sayan (ES), the Kuznetsk Alatau (KA), and the Urals (U). Paleorecords and species distribution modeling indicated preservation of Siberian stone pine in these mountains and near big lakes (Lake Baikal and Lake Teletskoe) during the Last Glacial Maximum (LGM). Nonetheless, processes of migration from these refugia were heterogeneous: WSA has never expanded after the LGM beyond its current range; ES occupied the eastern geographic range of the species; KA and U had common history before the LGM and got isolated during LGM. Moreover, refugia and migration routes of Siberian forest species ( Larix sibirica and Abies sibirica ) were different from those of P. sibirica despite similar ecological preferences. Pinus sibirica occupied the West Siberian Plain from the Urals and Kuznetsk Alatau, whereas A. sibirica and L. sibirica expanded from Lake Baikal and the Sayan Mountains, respectively. Thus, our results substantially complement existing notions of South Siberia Mountains, Lake Baikal area, and Urals as glacial refugia for Siberian stone pine.