LATE GLACIAL AND HOLOCENE VEGETATIONAL AND CLIMATIC CHANGES IN THE DONETS-AZOV AREA (UKRAINE), INDICATED BY POLLEN

Fourteen Holocene pollen successions (seven of them with the Late Glacial) were studied in steppe to the north of the Sea of Azov. They are natural sections of relief depressions and archaeological sites. During the Late Glacial interstadials, boreal forest-steppe existed – Betula-Pinus forest with few Picea, and meadow steppe. The climate was wetter than now, particularly during the Alleröd. The climate of Older and Younger Dryas was sub-periglacial – dry steppe dominated (especially during the Older Dryas), and shrub Betula appeared. At the warmer and wetter Early Preboreal (9.9-9.4 ¹⁴C ky BP), pine forest with admixture of broadleaf trees alternated with grassland. Xeric steppe spread during the cold Late Preboreal (9.4-9.0 ky BP), though shrub Betula was absent. An increase in warmth and humidity occurred at the Early Boreal (8.5-8.6 ky BP), when birch-broadleaf forest alternated with meadow steppe. The climate was cooler and wetter than now. During the cool and arid Late Boreal (around 8,110±120), broadleaf species declined and grassland spread. The Early Atlantic (8-6.1 ky BP) had the optimum climate for broadleaf forest expansion (wetter and warmer than now). Carpinus appeared for the first time. A short drier phase occurred 7.0-7.2 ky BP. At the Late Atlantic thermical optimum, a role of broadleaf trees in forest was the largest, though the areas of forest were reduced (an increase of evaporation in a warmer climate). At the end of AT-3 (5.2-5.0 ky BP), meadow steppe strongly dominated, and Carpinus disappeared. The Early Subboreal (4.6-4.2 ky BP) was wetter and cooler than nowadays (forest-steppe with predominance of boreal trees). The Middle Subboreal had dry climate (spread of Artemisia-Poaceae steppe at 3.8- 3.5 ky BP). During the Late Subboreal, the wet phase firstly occurred at 3.5-3.0 ky BP (the forest-steppe had less broadleaf trees than during the Atlantic), and then again the dry phase of xeric steppe happened at 2.9-2.7 ky BP. During the Subatlantic, forest-steppe vegetation existed for the last time at 2.6-2.2 ky BP. Later on, climatic oscillations were reflected in alternation of meadow steppe and grassland. As the tangible human impact on this steppe area appeared during the last 300 years, the reduction of broadleaf trees after 800 yr BP could be related to the ‘Little Ice Age'.