Dietary transition in native populations of northern Tierra del Fuego during the salesian missionary period: an isotopic approach

Abstract

The Salesian mission La Candelaria was run from 1893 to 1928 in the north of Tierra del Fuego, but its cemetery was in use until 1948. Historical sources suggest that the natives living there underwent marked dietary changes with respect to the hunter-gatherers of the area. The change can be characterized by a large increase in the consumption of flour, rice, potatoes, and sugar, in replacement of guanaco, as their main food source. Our objective is to evaluate the dietary transition experienced by the inhabitants of the mission through the analysis of stable isotopes of carbon and nitrogen on bones (collagen, apatite) and teeth (dentin, enamel) of 23 individuals exhumed from the cemetery. The δ¹⁵N values in collagen (δ¹⁵N_c), and δ¹³C values both in collagen (δ¹³C_c) and in apatite (δ¹³C_a) of samples from the cemetery were lower than the values published for the region in pre-contact periods. Within the cemetery, the δ¹⁵N_c, δ¹³C_c and δ¹³C_a values were lower than those of δ¹⁵N_d (dentin) and δ¹³C_e (enamel), but there were no differences between δ¹³C_c and δ¹³C_d values. The δ¹⁵N_d and δ¹³C_d values were significantly lower than the isotope values of collagen for pre-contact periods. The results are consistent with the hypothesis raised by historical sources and suggest an imbalance in the diet, with a higher proportion of carbohydrates and a lower proportion of animal proteins in the inhabitants of the mission in comparison with the hunter-gatherers of Tierra del Fuego of pre-contact periods.