ДИНАМИКА ЛАНДШАФТОВ И КЛИМАТА НА СЕВЕРО-ЗАПАДЕ СРЕДНЕРУССКОЙ ВОЗВЫШЕННОСТИ В ГОЛОЦЕНЕ

New results of complex palaeogeographical investigation of the Klyukva karst-suffosion bog (the Belev raion of theTulaoblast) and the reconstruction of the Holocene dynamics of vegetation resulting from climate changes and anthropogenic impact are presented. During the boreal period of the Holocene the territory under study was covered mainly by pine and birch forests, probably inherited from the periglacial vegetation cover of the Late Valdai Ice Age. The broadleaved forests appeared within theUpperOkaRiver basinabout 7800 years ago (the Atlantic period) and about 7500 years ago oak, lime and elm forests with birch became the dominant component of the vegetation cover. Changes in bog vegetation, testate amoebas, characteristics of peat stratum and surrounding vegetation cover suggest that climatic conditions of the late Atlantic period (thermal maximum of the Holocene) were warmer and dryer as compared to modern ones, probably due to lesser summer precipitation. During the second half of the Holocene the most radical changes, both local (in bog ecosystems) and regional (in the Upper Oka River basin, the north-western part of the Srednerusskaya Upland), occurred 5000 and 2500 years ago, in line with the principal milestones of the natural environment evolution. Profound changes of the vegetation cover took place in the historical time as a result of the anthropogenic activities. Wide distribution of spruce during that period could be probably attributed to the anthropogenic impact rather than to climate change, because after the clearing of broadleaved species the spruce has gained in competitiveness.