Lateglacial and Holocene vegetational and climatic changes in the southern taiga zone of West Siberia according to pollen records from Zhukovskoye peat mire

Pollen analyses and radiocarbon dates from Zhukovskoye peat mire (56°20′N, 84°50′E), situated in the south-eastern part of the boreal forest (taiga) zone of West Siberia, suggest that climatic oscillations of the Lateglacial were well expressed in the region. These events are tentatively correlated with the Alleröd warming and the Younger Dryas cooling in Europe. In the Alleröd, complex vegetation combined larch copses with birch and spruce in wetter places with dry steppe communities dominated by Artemisia and Poaceae. The climate was cool and continental, with moderately warm summers. Due to the onset of colder and drier climate in the Younger Dryas the wooded areas were reduced, while xerophile herbaceous communities with periglacial steppe elements expanded. Following the warming in the Early Holocene, woody vegetation was established in the area. At the early stage the woods were dominated by birch, larch and Scots pine. Later an increase in moisture caused formation of Picea taiga forest with Abies and Pinus sibirica. In the relatively warm and humid climate the process of mire development spread over a major part of West Siberia. Comparison with the published data on other sites in West Siberian plain shows that the warmest conditions existed in the region approximately 6–5 ka BP (non-calibrated 14C age). The warming is indicated by spread of more heat-demanding forest communities in the taiga zone and by a shift of the forest/tundra boundary to the north. Cooling in the late Holocene caused a decline of the relatively thermophile species in the forests and a retreat of the northern tree line to the south. Development of the raised peat bogs in the southern taiga sub-zone of West Siberia reflected in pollen profiles shows that this cooling continued in Subatlantic time.