Sukcesja roślin interglacjału mazowieckiego w Białej Podlaskiej

Abstract

PLANT SUCCESSION OF THE MAZOVIAN INTERGLACIAL AGE AT BIAŁA PODLASKA Summary Results of palynologic studies of sediments from five sections of the Biała Podlaska site (14, 16, 17) allowed to distinguish 6 periods of plane evolution, preceded by deposition of material with plant remains of mainly secondary deposit. 13 pollen zones and one of the secondary bed were also distinguished. Floristic elements noted in sediments of this geologic horizon enable its correlation with the first phases of development of pioneer vegetation, containing numerous heliophytes. The period I comprisses two pollen zones BP - A and B. It presents phases of development of firstly forestless plant communities and then of thin, finally compact and well modelled forests of a boreal zone: pine-birch ones with spruce, alder, larch and appearing elm, oak, ash and occasionally linden. The period II indicates the main stage of well developed and compact boreal forests. It can be subdivided into two phases (pollen zones BP-C and D). Spruce and alder were the main trees; pine and birch still existed but were less important, the same as arising mesocratic trees (oak, elm, ash, linden). Hazel appeared too, accompanied in the younger part by yew. The area of Biała Podlaska was occupied by floristicly rich and well developed communities of a boreal forest type but with certain atlantic features. Bushes of slightly greater climatic demands (Hedera, Viscum) appeared and Salvinia in a lake water. The period III was considered for a climatic optimem sensu lato of this interglacial. It indicates a floristic variability and can be subdivided in to at least four pollen zones: BP-E - Taxus, Picea, Alnus (Pinus), BP-F - Pinus, Picea, Alnus (Carpinus, Taxus), BP-G - Carpinus, Abies, Quercus, Corylus (Pinus, Alnus) and BP-H - Carpinus, Quercus, Corylus, Abies (Alnus). The pollen zones BP-G and H represent forest communities of the atlantic type. Warm, wet and mild climate of this period was indicated by Vitis, Buxus, Ilex, Ligustrum and development of previously present Hedera, Viscum and Salvinia (see Fig. 1). The period IV presents a vegetation development in the final part of the interglacial. It is subdivided into two pollen zones: BP-J - Pinus, Betula, Sphagnum (Picea, Carpinus, Abies) and BP-K - Pinus, Picea, NAP (Larix). Trends of climatic-floristic changes noted in these zones were also distinguished in sediments of other synchronous section, coming among others from Komarno (13, 15) and Adamówka (1). The period V presents the flora of an interstadiał warming, defined as the pollen zone BP-L - Pinus, Abies, Carpinus (Quercus, Alnus). Within this zone Pterocarya reaches its maximum. Bushes of slightly greater climatic demands, among others Buxus and Viscum appeared. Forest communities were dense, mainly with pine and admixture of larch and spruce. More fertile habitats could be vastly occupied by fir, hornbeam, oak, hazel, linden, elm and ash. The period VI of younger scarce and forestless communities was indicated by two pollen zones: BP-M - Pinus, Betula, NAP and BP-N - Betula, NAP, Artemisia (Pinus). A climate during the final part of this period is to be defined as arctic or subarctic one. Lake waters were commonly occupied by algae of the genus Pediastrum, not indicated in the pollen diagram (Fig. 1, see 14, 16, 17).