Interstadial inland dune slacks in south-west Slovakia: a multi-proxy vegetation and landscape reconstruction

Abstract

Palaeoecological studies spanning back to the Bølling/Allerød (GI-1) Interstadial of the Late Glacial in the whole Western Carpathians and adjacent lowlands are extremely scarce. To improve our knowledge about the landscape structure and diversity of wetland habitats, we analysed two palaeoecological interstadial sequences of pollen and macrofossils (bryophytes, vascular plants and molluscs) from the sandy landscape of the Borská lowland (southwest Slovakia). The deposits differed between the two sequences analysed, consisting predominantly of lacustrine chalk or brown-moss sedge fen peat, respectively. The results showed that, during wetter and warmer conditions during the Interstadial, open large dunes had been stabilised by pine woodlands admixed by birch. Contrary to the Podunajská lowland, which is situated eastwards towards the centre of the Pannonian Plain, broadleaf thermophilous trees such as Ulmus, Quercus and Tilia were almost absent in the study region, which suggests an importance of the bedrock for Late-Glacial forest vegetation. Salix, Alnus and Betula nana scrubs were probably scattered across wetlands. Active dunes were occupied by Hippophaë rhamnoides and steppe vegetation with grasses, Artemisia and Helianthemum. Low abundance of Chenopodiaceae pollen suggests that the sandy bedrock was probably unfavourable for the development of salt-rich habitats. Wetland habitats were diverse and abundant in the inter-dune space, partly resembling recent coastal dune slack vegetation or alluvial salty grasslands in continental central Asia. The wetland habitats comprised aquatic habitats with Myriophyllum, Potamogeton filiformis, P. pectinatus, P. pussilus, Sparganium minimum and planktonic algae (Pediastrum and Botryococcus), strongly continental calcareous-fens with Blysmus rufus and Triglochin maritima, boreocontinental brown-moss sedge fen fens with Drepanocladus trifarius, Carex lasiocarpa, Menyanthes trifoliata and Scorpidium scorpioides) and reed beds with Cicuta virosa, Phragmites and Schoenoplectus tabernaemontani. Remains of these unique wetland mosaics have recently disappeared because of human activities including peat extraction and dune stabilisation by pine plantations, which have transformed the modern landscape.