Dietary changes across time: Studying the indigenous period of La Gomera using δ13C and δ15N stable isotope analysis and radiocarbon dating

Objectives This article presents new radiocarbon and isotopic data to provide further information about the diet of the indigenous population of La Gomera and its possible changes across time. Materials and methods delta C-13 and delta N-15 of 53 human and 19 faunal samples from different sites on the island have been obtained and analyzed. Of these, 52 have been radiocarbon dated to provide insight on chronological changes. Results Human dates range from the 3rd to 15th centuries AD, while faunal dates range from the 1st to 17th centuries AD. Stable carbon and nitrogen values are significantly different between the human and goat samples and have also a trophic increase of 3.4 parts per thousand. Although male and female delta N-15 data are not significantly different. Both delta C-13 and delta N-15 values of both human and animal samples tend to discretely decrease over time. Discussion Radiocarbon dates from humans correlate with other dates obtained in the rest of the archipelago. Animal radiocarbon dates generally coincide except for one date, which requires further study. Isotopic delta N-15 data suggest a mix of marine and terrestrial protein consumption in humans, the latter being more abundant given the seasonality of the first. delta C-13 data also suggest a possible mixed diet in humans, with a predominance of C-3 plants, like Hordeum vulgare, the only grain found in archaeological sites so far. Variations of both delta C-13 and delta N-15 over time suggest a slight modification on the diet, which could be related to environmental changes.

Automated summary

New radiocarbon and isotopic data provide insights into the diet of the indigenous population of La Gomera and suggest possible changes over time. Carbon and nitrogen values show differences between human and animal samples, with a decrease in values over time. The data also indicate a possible mixed diet in humans, with a predominance of C-3 plants.