ИСТИНА

The late Holocene dynamics of forest-steppe landscapes of Central East European plain and the history of its agricultural land-use have been reconstructed on the base of pollen, plant macrofossil and radiocarbon data from a number of sections in the Upper Don River basin (the Kulikovo Battle-Field). The mire Bolsheberesovskoe and two sections of flood plain have been sampled and studied. The reconstruction of main parameters of past climate (mean July and January temperature and annual precipitation) was carried out with the use of Klimanov’s (1984) transfer function. The study of the key sections of the area of the Kulikovo Battle-field enabled us to follow up the evolution of landscapes in the forest and steppe ecotone in the Upper Don basin over the last 7 thousand years and also to assess the human impact on natural environment in the region. In the middle Holocene the territory was occupied by steppe landscapes. Significant changes in the plant cover of the Kulikovo Battle-field area are attributed to the termination of the Atlantic phase and the early Subboreal. The climate cooling in the Subboreal phase was favorable for forest expansion to the south and development of forest-steppe vegetation. The Subatlantic period was characterized by complex temporal dynamics of climate and vegetation. Relative reductions in annual precipitation at the beginning of the period, accompanied by the rise of summer temperature, from 20°-22°C to 22°-24°C, were sufficient to cause a shift from the forest-steppe to typical steppe communities. In the middle Subatlantic the climate became cooler and more humid that is induced a return of forests into the Upper Don River basin. In the latest phase of the Subatlantic the portion of forests in the vegetation is further increased. Climatic reconstructions have shown that landscape dynamics on the area of the Kulikovo Battle-field during the late Holocene were determined by changes in effective moisture (an excess of precipitation over evaporation). Probably, frequencies of fires are increased (early Subboreal, early Subatlantic) under growth of summer temperatures by 1-3°С comparing to their present values and keeping the amount of precipitation close to modern climate. On the other hand, an increase of precipitation could be a reason of catastrophic erosion and accumulation processes in river valleys and ravines. The high biodiversity of the forest-steppe area made this region a very attractive for early human groups. Signals of anthropogenic changes in the vegetation and clearly pronounced in the pollen spectra since the middle Atlantic. Neolithic hunter-gatherers were fully adapted to natural environments, and their impact on the vegetation was negligible. During the Bronze Age, several indices of agricultural activities are appeared in the pollen spectra, however the human-induces changes in the vegetation are remained very small until the medieval period. Large-scale landscape changes and the degradation of natural vegetation became conspicuous only over the past two of three centuries. The present-day state of plant communities in the Upper Don River basin is totally controlled by anthropogenic factors.