Implications of the Early-Middle-Pleistocene transition in Central Europe: The Arternian interglacial macroflora near Voigtstedt, Thuringia, Central Germany

Only little information on flora and vegetation in Central Europe during the late Early Pleistocene is so far available. In the present article, macroscopic plant remains preserved in lacustrine Muschelton sediments near Voigtstedt, Thuringia, Central Germany during the Arternian interglacial are described in detail. More than 16,000 plant remains representing 119 taxa were recovered, dominated by aquatic, marshland, and riparian species indicative of eutrophic, lime-rich, and locally brackish lake water conditions. The assemblage reflects a mosaic of habitats colonized by aquatic macrophytes, reed beds, alder swamps, and floodplain forests. A small proportion of terrestrial taxa indicates the presence of xerothermic shrub and grassland vegetation in the surroundings of the palaeo-lake indicating at least seasonally arid, continental climate influences. Only five Tertiary relict taxa were identified, including Stratiotes brevispermus, Scirpus atroviroides, Alisma plantago-minima, Ranunculus gailensis, and Oenanthe mazovica, a conspicuously low number compared with other Early Pleistocene floras, supporting initial, preliminary palynological inferences that many thermophilous Tertiary species became extinct during an exceptionally harsh cold phase preceding the Arternian interglacial. Floristic affinities with the Augustovian and Korchevian macrofloras, which both overlie the oldest till in their respective study area, suggest deposition in the aftermath of the first advance of Northern ice sheets in Eastern Europe correlated with the 0.9 Ma event. However, partly differing species compositions and palaeomagnetic signals among the compared sites highlight uncertainties in correlating individual interglacials across Europe. Therefore, a precise correlation with Marine Isotope Stages remains unresolved due to the lack of high-resolution palynological data. • Detailed analysis of plant macro-remains found in late Early Pleistocene lake deposits. • Floristic resemblance to Augustovian (Poland) and Korchevian (Belarus) macrofloras. • Lack of Tertiary relict species suggests deposition after the 0.9 Ma event. • Correlation with MIS remains unresolved due to the lack of high-resolution palynological data.