HOLOCENE VEGETATION AND CLIMATE HISTORY OF SOUTHWESTERN UKRAINE

The fossil pollen records of two swamps in the forest-steppe and steppe zones of southwestern Ukraine were studied to reconstruct the Holocene vegetation and climate history. At Dovjok swamp (forest-steppe) the record extends from the first half of the Atlantic at c. 8000 BP through the Subboreal and Subatlantic. Vegetation of the first half of Atlantic was more thermophilous, suggesting a warmer climate than at present. By the late Subboreal (3300-2800 BP) vegetation and climate became more similar to modern natural conditions. In the Subatlantic period human impact became the major factor in vegetation change. At about 800-900 BP increased erosion rates led to cessation of peat formation. At Kardashinski swamp (steppe zone) sedimentation started at c. 8000 BP. Increased moisture during the later Atlantic allowed broadleaved forests to expand in the lower Dniepr Valley and steppe cover to become more mesophilous. Comparison of the Kardashinski record with archaeological data confirms the location of the ''Hylaea'' forest described by Herodotus as being adjacent to the Dniepr. In general, the Dovjok and Kardashinski records suggest that the steppe-belt was more sensitive to moisture fluctuations than the forest-steppe belt. Anthropogenic pressures on soil and vegetation cover were much more severe in the forest-steppe belt. It can be concluded that major vegetation changes in the Subatlantic in the forest-steppe belt were related to agricultural development in the region. In the steppe belt vegetation changes were primarily under climatic control.