Vegetation response in the southern Lake Baikal region to abrupt climate events over the past 33 cal kyr

Abstract

We reconstructed vegetation changes and fire events in the southern Lake Baikal region over the past 33calkyr using a sediment core from the Buguldeika Saddle, southern Lake Baikal, to examine vegetation response to past short-term climate variations. Herbs, such as Artemisia and Asteraceae, were dominant just before the Last Glacial Maximum (LGM). Low pollen accumulation rates (PARs) with little herb pollen indicate sparse herbaceous vegetation cover during the LGM. Picea expanded after the Bølling interval, suggesting expansion of riparian areas, and shrub Alnus rapidly increased during the following Allerød interval. Abies and Pinus subgen. Haploxylon began to increase at the beginning of the Holocene and Pinus subgen. Diploxylon has been highly dominant since the middle Holocene. The vegetation change after the LGM is similar to that from other sites in the Lake Baikal region, but the responses to short-term climate events are pronounced. Fluctuations in herb elements and vegetation cover as indicated by the PAR correspond to the Younger Dryas (YD) cooling event. The decline in the PAR and increase in herb taxa were remarkable at the beginning of the YD, but Larix and Picea trees were distributed in river valleys near Lake Baikal in the latter half. The rapid expansion of Betula and Artemisia following frequent fires in the early Holocene may have been in response to the 8.2calkaBP cooling event. From these findings, the southern Lake Baikal region, including the Selenga River basin, may possibly have been more sensitive than other parts of the region to abrupt climate changes.