Detection of the most probable Pleistocene microrefugia on the northern macroslope of the Khamar-Daban Ridge (Southern Prebaikalia)

Currently, the natural zone of the broad-leaved (nemoral) forests in Eurasia has a wide disjunction that falls on the most continental part of Siberia. However, there are several well-distinguished nemoral refugia on the foothills of some mountains in Southern Siberia where one can find a higher concentration of the preserved assembles of nemoral relict species. The eastern “outpost” of the Siberian refugia is the northern macroslope of the Khamar-Daban Ridge. We analyzed the present distribution of 27 nemoral relict plant species on the Khamar-Daban Ridge to detect the most probable Pleistocene microrefugia. Our results revealed that the microrefugia are most probably confined to the valleys of Utulik, Babkha, Snezhnaya, Pereemnaya, and Mishikha rivers. Based on the ranges of species distributions within the distinguished microrefugia, six groups of relicts were identified. Evidently, species from those groups differed in their survival strategies during glaciations, as well as subsequent reexpansion during the interglacial time.