Holocene recolonization and extinction of the pond turtle, Emys orbicularis (L., 1758), in Europe

Abstract

We reconstruct the Holocene range fluctuations of the European pond turtle (Emys orbicularis) for northern and Central Europe. Based on 529 subfossil records and radiocarbon dating of critical finds, we provide evidence that E. orbicularis experienced a rapid range expansion with Holocene warming. Phylogeographic data argue for a colonization of northern and Central Europe from a glacial refuge located in the south-eastern Balkans. Already in the Late Preboreal (9100–8600calBC) the species occurred in northern Central Europe and was widespread in Denmark and southern Sweden (Skåne) during the Boreal (8600–7100calBC). The maximum range extension occurred during the Holocene climatic optimum (Atlantic: 7100–3750calBC), with records in southern England, middle Sweden, and northern Estonia. After the early Subboreal (3750–1750calBC) northern populations collapsed, coinciding with a climatic cooling and oceanization. Northern populations were most likely established via long distance dispersal (rafting using rivers debouching in the North and Baltic Seas); after northern Europe was reached, a minimum dispersal of 50km per 100 years may be hypothesized for the Boreal.