Paleodiets in hunter-gatherer groups of the Pampean-Eastern Patagonia transition (Argentina) during the last 6000 years

Our objective in this article is to assess paleodiets and subsistence patterns, through stable isotope (delta C-13(ap), delta C-13(col) and delta N-15) analyses, of hunter-gatherer groups from the eastern Pampa-Patagonia transition (Argentina) during the Middle-Late Holocene (ca. 6000-250 years BP). We analyzed 44 adult individuals of both sexes. During the Middle Holocene, terrestrial herbivores, marine fish, and possibly pinnipeds played an important role in the diet, whereas toward the Late Holocene terrestrial herbivores and freshwater fish became more important parts of the diet, with the consequent decline in the consumption of marine resources. We detected a higher intake of vegetables (mainly C-3 plants) beginning about 1000 years BP. There is a trend during the Middle and possibly initial Late Holocene in the spatial distribution of stable isotope values: the individuals buried at a distance of ca. 20 km from the Atlantic coast present marine and mixed diets, whereas those individuals located at greater distances (up to ca. 130 km) exhibit terrestrial diets. These differences could be related to restricted home ranges of these hunter-gatherer groups and/or a social demarcation of the landscape, indicating possible territorial behaviors. Changes in diet over time resemble those reported for the southeastern Humid Pampa, which likewise observes a more continental diet during the Late Holocene.