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An environmental reconstruction of mid-late Holocene vegetation, climate and lake dynamics was inferred from pollen and diatom records of Lake Big Yarovoe in Kulunda, southern West Siberia. The reconstruction suggests a general prevalence of steppe during the last 4.4 ka. Under a relatively warm and dry climate, open semi-desert and dry steppes with patchy birch forest spread between 4.4 and 3.75 ka BP. The largest development of conifer forest started in Kulunda after 3.75 ka BP. The onset of the Late Holocene is characterised by the dominance of steppe with birch and pine forests in the lowlands and river valleys. After AD 1860, open steppe and semi-desert vegetation with fragmentary birch forest have been dominant in Kulunda, along with a sharp reduction of conifers. These results are in agreement with the general pattern of the Holocene environmental history of the surrounding areas, including the Baraba forest-steppe, Kazakh Upland and Altai Mountains. The penetration of coniferous forest into the Kulunda steppe after 3.75 ka BP was related to its geographical location northwest of the Altai Mountains. The economic activities of the ancient population of Kulunda depended on the environmental changes during the Holocene. (C) 2012 Elsevier Ltd. All rights reserved.