Holocene vegetation evolution and climatic dynamics inferred from an ombrotrophic peat sequence in the southern Altai Mountains within China

Based on pollen data of 274 samples from a 550-cm core at Kelashazi Peat in the southern Altai Mountains within China, we reconstructed the Holocene vegetation dynamics and climatic change. The pollen assemblages and the associated biome scores indicate that the vegetation in Kelashazi valley was dominated by alpine meadows during the early Holocene (before ~8.2 cal. kyr BP) and by taiga forests in the middle Holocene (~8.2-~5.6 cal. kyr BP) that was followed by an expansion of alpine meadows (~5.6-~3.2 cal. kyr BP). The pollen-based temperature index-indicated thermal maximum lasting from ~8.0 to ~5.6 cal. kyr BP was consistent with temperature stack for 60–30°N and the later onset warming at Kelashazi Peat was associated with the cooling influence of remnant ice sheets in the early Holocene. The pollen-based increasing moisture index curve from Kelashazi Peat is in a good agreement with the synthesized decreasing aridity index curve in low-elevation regions of the Altai Mountains and the surrounding areas during the data-overlapping period between ~12.0 and ~3.2 cal. kyr BP. The Holocene wetting trend at Kelashazi Peat might have resulted not only from the increasing trend of NAO-related winter precipitation but also from the increasing trend of AMO-modulated summer precipitation.