Present-day and mid-Holocene biomes reconstructed from pollen and plant macrofossil data from the former Soviet Union and Mongolia

Fossil pollen data supplemented by tree macrofossil records were used to re construct the vegetation of the Former Soviet Union and Mongolia at 6000 ye ars. Pollen spectra were assigned to biomes using the plant-functional-type method developed by Prentice ct al. (1996). Surface pollen data and a mode rn vegetation map provided a test of the method. This is the first time suc h a broad-scale vegetation reconstruction for the greater part of northern Eurasia has been attempted with objective techniques. The new results confi rm previous regional palaeoenvironmental studies of the mid-Holocene while providing a comprehensive synopsis and firmer conclusions. West of the Ural Mountains temperate deciduous forest extended both northward and southward from its modern range. The northern limits of cool mixed and cool conifer forests were also further north than present. Taiga was reduced in European Russia, but was extended into Yakutia where now there is cold deciduous fo rest. The northern limit of taiga was extended (as shown by increased Picea pollen percentages, and by tree macrofossil records north of the present-d ay forest limit) but tundra was still present in north-eastern Siberia. The boundary between forest and steppe in the continental interior did not shi ft substantially, and dry conditions similar to present existed in western Mongolia and north of the Aral Sea.