Environment and subsistence in north-western Europe during the Younger Dryas: An isotopic study of the human of Rhünda (Germany)

The human skull of Rhunda in Central Germany is one of the rare human remains belonging to the cold episode of the Younger Dryas or GS-1 based on direct radiocarbon dating (10,200 ± 60 uncal BP GrA-15947). The return of periglacial conditions from northern France to northern Germany favoured the expansion of the reindeer herds, as testified by their numerous remains found at the Ahrensburgian sites. The isotopic composition of the collagen (δ 13 C coll and δ 15 N coll ) of the Rhunda individual provides insight into the relative dietary contribution of terrestrial ungulates, such as reindeer, compared to the intake of aquatic resources. The systematic higher δ 13 C coll values found for reindeer compared to horse during the Younger Dryas in northern Germany, the Ardennes and south-western England result from a different diet specialization, i.e. the high consumption of lichen by reindeer. The isotopic pattern evidenced in the Pleniglacial reflects such a niche partitioning, while the isotopic pattern of the Late-Glacial Interstadial reveals overlapping ranges in 13 C abundances in the different ungulates species, resulting most likely from a decrease in niche diversity. Despite their isotopic variability linked to trophic position and habitat, the freshwater fishes of the Belgian Ardennes show systematic higher δ 15 N coll values (6.6 to 11.7‰) than those of the terrestrial ungulates ( 15 N coll value of the Rhunda human (13‰) can thus be explained by an important consumption of freshwater resources, while the δ 13 C coll value (− 20.5‰) is too low to consider a significant input of anadromous fishes and their marine-influenced isotopic signature. The application of a Bayesian model confirms this pattern with a minimum contribution of 40% of aquatic resources as protein source for the human diet. In contrast, the input of protein of terrestrial origin hardly exceeded 40% of horse and 20% of reindeer meat consumption. Although existing archaeological and isotopic evidence already suggests a significant use of aquatic resources during the Late-Glacial, the human of Rhunda illustrates an intensive exploitation of the freshwater ecosystem at a time and latitude where the access to palatable plants must have been challenging.