LAUSR

Abstract Mountainous areas of Central and Eastern Europe were crucial for the survival of temperate deciduous trees during the Weichselian glaciation. The distribution of these tree refugia was one of the key factors for the migration and composition of temperate forests during the Late Glacial and Holocene. In this article, a palaeoenvironmental reconstruction from the landslide palaeolake located within a lower montane zone in the northern part of the Western Carpathians (Beskid Makowski Mountains) is presented. A multiproxy approach, involving several biotic proxies, combined with organic carbon and nitrogen content and their isotopic ratio, supported by high stratigraphic accelerator mass spectrometry (AMS) 14 C dating was applied for the reconstruction of vegetation changes and their influence on the small lake ecosystem. The results revealed that forests dominated by Pinus sylvestris , Betula , and Picea abies , in which Pinus cembra and Larix decidua were an admixture, were present from at least ca. 11,240 cal BP. From ca. 11,130 cal BP, elm ( Ulmus ) started to spread, and ca. 70 (± 30) years later, it probably has become a prominent constituent of the local forests. This process was coincident with an increased fire activity and the retreat of P. cembra and L. decidua . The early spread of Ulmus in the lower mountainous forest ecosystem is an indirect evidence of the presence of its Late Glacial refugia in the Western Carpathians. The lake, functioning during that time, was characterised by high sedimentation rate (0.16–0.2 cm year − 1 ), low primary productivity, low Cladocera diversity mainly dominated by Chydorus sphaericus complex, and low Chironomidae concentration. The spread of aquatic vegetation, among them Potamogeton obtusifolius and Potamogeton friesii , in the lake was simultaneous to Ulmus expansion and the constant presence of P. abies macrofossils.