Change of vegetation and climate of Western Sayan Mountains and its interconnection with developmentof archeological cultures of area during second half of the Holocene according to spore-pollen data of peat deposits

Spore-pollen analysis of peat deposits of the Lugovoe mire inthe natural park Urochishe Ergaki located in the Western Sayan Mountains in the south of Central Siberia revealed 3 stages in developmentof vegetation cover during last 6000 years. During the first stage (6-5.1 ka B.P.) wet Abies forests had maximal spreading in theWestern Sayan Mountains. The second stage, the stage of birch forests (5.1-2.7 ka B.P.), was marked by wide spreading of birch on lowmountains north of the Western Sayan Mountains. Here birch forests (with Betula pendula) and birch forest-steppe existed on the placeof the current belt of chern forests (wet Abies sibirica-Populus tremula forests). In the mountain timberline was formed by Pinussibirica, above which a belt of subalpine thick shrublands from Duschekia fruticosa and shrub birches was wide spread. Wet Abies forestswith herb-fern under-layer were spread below the altitudinal belt of Pinus sibirica mountain forests and in intermountain valleys.During the third stage (from 2.7 ka B.P. till present time) pine (Pinus sylvestris) forests begin to dominate over birch forests on lowmountains north of the Western Sayan Mountains. In the mountains the altitudinal belt of subalpine thick shrublands decreased considerably,and the role of ferns in herbal under-layer of mountain forests also decreased. The characteristic feature of the spore-pollen diagramof the Lugovoe mire is that maxima of pollen of dry land plants Artemisia and Chenopodiaceae correlate well with dry intervals ofclimate reconstructed for the forest-steppe zone of Western Siberia by Levina and Orlova [9], which is the evidence of the regional natureof these events. The correlation of palaeopalynological data of the Lugovoe mire (performed on the basis of the linear interpolationof radiaocarbon data) with published palaeoreconstructions for the south of Western Siberia [9], and with the data of archaeologicalinvestigations in Khakassia [10] enabled us to reconstruct natural environments on the background of which different archaeologicalcultures developed and changed each other in Khakassia. Arriving of the first human tribes to Khakassia, blooming of first agriculturalcattle-breeding and later predominantly cattle-breeding cultures took place during the birch stage in the development of vegetation.Later, during the Iron Age (1000 B.C) the Scythian culture (Tagarskaya archeological culture of Dinlin) bloomed during the wet stage ofthe climate. It was changed by Kyrgyz archeological culture in the conditions of the drier climate. In the spore-pollen diagram of theLugovoe mire the pollen of anthropogenic indicators (Cannabis, Urtica and Hordeum) is more abundant during the time of bloom ofagricultural cultures and absent or rare during the dominance of cattle-breeding cultures. A characteristic feature is that spreading ofsheep breeding in Khakassia caused predominance of grasses in the steppe vegetation of intermountain depressions north of the SayanMountains. This global change in the vegetation cover of the steppe happened during one hundred years. The maxima of charcoal inpeat deposits of the Lugovoe mire mark well the bloom of different archeological cultures in Khakassia.

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