Vegetation and climate of southern Siberia in the Late Holocene at decadal resolution: a multiproxy study of the Lake Shira lacustrine sediments, Minusa Basin

Abstract

New AMS¹⁴C-dated records of changes in the natural environment of southern Siberia from varve sediments of Lake Shira (Minusinsk Basin) are presented. The results allow reconstructing the history of vegetation, biomes, climate, relative productivity of the lake system, changes in the lake catchment erosion, and water levels in the lake itself over the past 2980 cal. years with an average temporal resolution of 21 years. The new reconstructions indicate a wet regional climate between 2980 and 2650 cal yr BP and its gradual aridization later. At the same time, the climate of the basin itself was more arid, thus providing the development of steppe and meadow-steppe communities around the lake in the last 2980 years. Variations in the Artemisia/Chenopodiaceae pollen ratio, considered as an indicator of moisture available to plants, suggest a slight increase in the moisture level in the Minusa Basin from 2980 to 50 cal yr BP and its noticeable decrease in the last 50 years. Reconstructions show that changes in vegetation around Lake Shira in the Late Holocene were mainly caused by large-scale circulation processes that changed the regional moisture balance. Steppe vegetation turned out to be very sensitive to moisture changes on a decadal scale. No clear pollen indicators of anthropogenic impact on vegetation were found in the new pollen record.