ИСТИНА

Reconstruction of the spatial landscape pattern during the Late Pleistocene loess accumu-lation in the central part of the East European Plain is one of the most interesting issues in pale-oenvironment of loess region. Our studies are based on combination of landscape approach and pollen data. We use map of current landscape structure of this area and results of pollen analysis from the Yudinovo Late Paleolithic site (Sapelko, 2014) supplemented by previously published evidences of fossil flora from loess sediment of the Desna River basin (Novenko, 2006). The Yudinovo section (and the Late Paleolithic site) is located in the Sudost’ River valley (tributary of the Desna R.) 15 km upstream of the town of Pogar (Bryansk Region), at the southwestern margin of the Yudinovo Village. The section is located on the right bank of the river, at the 2 floodplain terrace at about 7–10 m above the river bed. Two cultural layers were determined in the Yudinovo Late Paleolithic site. Dating of the lower cultural layer is 15000–13500 14C yr BP while dating of the upper layer is 12500–12000 14C yr BP (Khlopachev, 2015). Our spatial reconstructions was performed for the period previous to human occupation wthen the main natural processes were loess accumulation in the periglacial zone of the Late Valdai Glaciations. According to obtained results landscape of the study area during loess accumulation was characterized by mosaic structure and included combinations of various plant communities these belonged to particular landforms. The steppe and meadow-steppe communities seem to be domi-nant on flat interfluves (proportion of non arboreal pollen in the pollen assemblages is 80–90%). The fossil flora contains typical species of those communities — xerophytes and xerohal-ophytes (Eurotia ceratoides, Kochia .prostrata, Ephedra distachya, Artemisia); those plants are indifferent to temperatures and grow at present in southern steppes, deserts and semi-deserts. Besides, the periglacial steppe formations included Chenopodium viride, Ch. vulvaria, Kochia la-niflora, Thalictrum contortum, etc. Judging from ecological requirements of the species and char-acteristics of modern communities including those species, the periglacial steppes of the past suggest a rather simple structure, sparse ground cover, and reduced amount of grass as compared with dwarf shrubs. In typical assemblages with Eurotia, Kochia or Ephedra as edificators the de-gree of coverage is locally as low as 15–20%. Steppe meadow occurred in shaded and wetter local-ities on gentle slopes along with periglacial steppe communities. Plants of disturbed soils or bar-ren ground features noticeably in the vegetation, not only in river valleys, but also on flat inter-fluves. A considerable species diversity of this group suggests those communities were an im-portant component of periglacial environments and possibly covered large areas. The floodplain of Sudost’ valley was occupied by meadows, locally wet, with shrubs and isolated tree stands. The valley communities included microtherms which occur at present in tundra and forest–tundra (Betula nana, Botrychium boreale, and Selaginella selaginoides). The better protected habi-tats featured plant assemblages including patches of woodlands (Betula, Pinus), shrubs, and mes-ophilic meadow communities.