Effect of topographic position on differential biotic and lithological responses to the late glacial–early Holocene climatic oscillations recorded in sediments of two landslide fens (the Outer Western Carpathians,S Poland)

Abstract

Landslide fens are characteristic landforms of the Beskid Makowski Mountains area in the Outer Western Carpathians (S Poland) and contain rarely occurring late glacial and Holocene organic-minerogenic sedimentary sequences. Multi-proxy study (radiocarbon dating, loss on ignition, plant macrofossil and pollen analyses) was applied to verify whether the late glacial-early Holocene climatic and paleoenvironmental changes were recorded differently between two sites varying in topographic position within the same mountain massif: the Kotoń landslide fen characterized by the southern exposure and near-ridge position and the Klaklowo landslide fen characterized by the northern exposure and mid-slope position. Results revealed that the responses of biotic and lithological proxies to the climatic phases differs between the Klaklowo and Kotoń landslide fens mostly in relation to the smaller-scale climatic oscillations. The characteristics of the Klaklowo fen catchment, including area, shape, relief, bedrock geology and specific local landforms, could contribute to the much more pronounced signal of the GI-1b/Gerzensee oscillation and Preboreal oscillation at this site than in the Kotoń site. Expansion and/or decline of the dominating vegetation taxa (Pinus, Betula sect. Albae, Carex, Bryopsida) and changes in minerogenic matter delivery induced by the global-scale climatic reversals: GI-1a‒c /Allerød, GS-1/Younger Dryas and Holocene, occur approximately at the same time in both Klaklowo and Kotoń landslide fens and show no striking dependency on exposure or elevation. An exception is the longer survival of Larix decidua, Pinus sylvestris and Coniferae during the early Holocene at the Klaklowo site, probably facilitated by its northern exposure and diversified landslide relief.