Late Pleistocene and Holocene palaeoenvironmental changes in the northern Carpathian foreland: A case study of mollusc-bearing cave deposits from the Shelter in Smoleń III (southern Poland)

Cave deposits are great archives of terrestrial palaeoenvironmental conditions, but in the northern Carpathian foreland only few sequences represent long and stratified Upper Pleistocene and Holocene series. In this paper we analyse a record from the Shelter in Smoleń III (southern Poland), which has been considered a regional stratigraphic stratotype of Holocene clastic cave sediments. With an approximately 2 m long mollusc-bearing sequence, this site provides a high-quality malacological record of past climate and environments that have developed in the region over the last 14,000 years. The landscape transformation during the Late Pleistocene and the entire Holocene was demonstrated. The oldest and the poorest malacofaunas represent the cool and dry continental climate of the Bølling-Allerød phases. A mosaic of open and forested habitats developed at that time. At the beginning of the Holocene, species of coniferous forests expanded in the region. The characteristic feature of the sequence is prolonged presence of the glacial relic Vallonia tenuilabris, which disappears in the Early Holocene. The Middle Holocene fauna is dominated by warmth-demanding species, which represent mixed and deciduous forests developed in a warm and humid climate with distinct oceanic influences. Some disturbance in the development of woodland assemblages, presumably connected with climate deterioration, is observed around 8200 cal. BP. The youngest (Late Holocene) fauna is characterized by increased numbers of snails with wider ecological tolerance and gradual deforestation in the studied region. The malacological record of Shelter in Smoleń III may serve as a reference for other sites with cave deposits on the northern side of Carpathian Mountains.