Isotopic biogeochemistry and the palaeoecology of the mammoth steppe fauna

The ecological structure of the mammoth steppe fauna remains quite unclear. Stable isotope biogeochemistry of fossil collagen can help determining the discrimination in food resources among different herbivorous species, due to differences in carbon and nitrogen isotopic signatures in plants. Especially differences in nitrogen sources for different plants, such as grass, bushes and heather, lead to distinct isotopic signatures. Mammoths present more carbon-13-depleted and nitrogen- 15-enriched collagen when compared to other herbivorous species, in all studied sites in Europe, Siberia and Alaska. One interpretation is that these isotopic differences reflect different dietary choices by herbivores, reindeer browsing on lichens, horse, woolly rhinoceros and bison grazing fresh grass, and mammoth consuming dry grass, with higher nitrogen-15 content than other plant resources. The low carbon-13 amounts of mammoth collagen might be due to fat utilisation in this species. This distinction between different herbivorous species leads to the potential to identify prey species of predators, including humans.