The case of two calcareous spring fens at the Carpathianpannonian interface in the North West of Slovakia

The study area is located in the part of Western Carpathians, where mountain ridges steeply rise from dry and warm Pannonian basin. In the Považský Inovec Mts, two small protected calcareous wetlands occur in different geographical position and contain suitable sediments. One represents a foothill site (initiated ca 13,000 cal. BP) while the other a low-mountain site (initiated ca 7400 cal. BP). We investigated fossil pollen, spores, and macroscopic remains of plants and molluscs from their sediments. We further reviewed archaeological data, calculated Macrophysical Climate Model (MCM) and confronted it with other palaeoclimatic proxies. Temperate deciduous trees (Quercus, Corylus, and Ulmus) occurred since Allerod, but their expansion was blocked by harsh climate in Younger Dryas when Larix, Pinus, and Betula nana still occurred. The climate firstly moistened at ca 9500 cal. BP and more distinctly at ca 8500 cal. BP, which was reflected by a strong calcium carbonate precipitation and expansion of Tilia cordata t., Hedera helix, and Ustulina. Although the MCM predicted rather stable climate since 8000 cal. BP, certain changes in aquatic mollusc abundances may indicate hydrological fluctuations Younger hydrological fluctuations may be alternatively explained by human activities as they correspond with macro-charcoal abundance and indicators of wetland openness. During existence of both fens they harboured only few fen plant and mollusc species specialised to low-productive sedge-moss fens. In the Middle Holocene both sites were encroached by woody plants (Alnus, Picea, and Salix) as most of the other spring fens in the Western Carpathians. Few fen specialists established there even since deforestation, presumably because of a high isolation of these fens and maybe also severe disturbances caused by grazing and/or hemp retting instead of mowing.