Neoholocene palaeoenvironmental changes in the Southern Roztocze region (SE Poland): The Kobyle Jezioro raised bog case study

The pollen diagram from the Kobyle Jezioro raised bog, situated in the source area of the Tanew River in the Roztocze region, covers the whole Neoholocene. The deposit thickness (about 3.5 m) has permitted high resolution pollen, peat (including macrofossils) and lithology analyses. Vegetational and palaeoenvironmental changes in this part of the Roztocze were recorded in pollen spectra and organic deposits. Palynological evidence shows the typical Neoholocene succession, which corresponds with the phenomena described from central Europe: from mixed deciduous forests at the decline of the climatic optimum, through hornbeam- and beech-dominated forests to pine forests. Peat accumulation in the Kobyle Jezioro peat-bog started during increased climatic humidity at the beginning of the Subboreal, and originally a fen peat was formed. Raised bog peat layers make up the uppermost 80 cm of the deposit. Within the fen deposits can be found layers of transitional peat, indicating short-term episodes of water deficiency in the early Subboreal phase (short-term climatic dryness) and towards its end (drainage of the bog resulting from the lowering of the groundwater table in the source area of the Tanew River). The growth of the raised bog started at the beginning of the climate deterioration in the Little Ice Age, and the unstable climatic conditions are reflected in the numerous periodical mineral (aeolian) material supplies in the developing ombrogenic bog. The accumulation of the younger section of transitional and raised peats during the Little Ice Age reflects the local hydrological changes in the source area of the Tanew River.