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Bronze Age diet and farming strategy reconstructed using integrative isotope analysis

Cross-sectional study suggests similar diets but different management of livestock among communities and a larger share of animal protein restricted to very few members of the elite

PLOS

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Credit: Dani Méndez-REVIVES

The El Algar society thrived in complex hilltop settlements across the Iberian Peninsula from 2200-1550 cal BCE, and gravesites and settlement layouts provide strong evidence of a marked social hierarchy.

Knipper and colleagues conducted carbon and nitrogen isotope analysis at two different El Algar hilltop settlements: the large fortified urban site La Bastida (in present-day Totana, Murcia), and the smaller settlement Gatas (Turre, Almería). Their sample included remains of 75 human individuals from across social strata, 28 bones from domestic animals and wild deer, charred barley (75 grains total), and charred wheat (29 grains) from the middle and late phases of El Algar civilization across the two sites.

The sampled human individuals showed no significant difference between isotope values for males and for females, suggesting that diets may have been similar between genders. However, "elite" individuals at La Bastida showed higher levels of both carbon and nitrogen. This might have implied that the people of La Bastida consumed higher levels of animal-based food, but the authors suggest that the isotope value differences between La Bastida and Gatas could in fact have resulted from similar dietary compositions. Nitrogen values are similar at both sites for barley, but higher for the domestic animals at La Bastida, meaning that diets with similar relative contributions of barley and meat/dairy products would have led to higher nitrogen values in the humans at La Bastida compared to Gatas.

The researchers found a strong reliance on cereal farming, supplemented by livestock, in the El Algar economy. The range and values of carbon in the barley and wheat sample reflect what was likely a dry, unirrigated landscape, though nitrogen levels in the cereal crops suggest the El Algar people applied animal manure to their fields. Cereals and their by-products appear to have contributed substantially to the forage of domesticated sheep/goats, cattle and pigs.

Though the sample used in this study is relatively small, and there are limitations to what can be sampled with this type of isotope analysis, this study shows the importance of considering the complete trophic chain in order to adequately interpret isotope data from human remains--and also demonstrates the sophistication of El Algar farming techniques.

Knipper adds: "It is essential to not only investigate human remains, but also comparative samples of different former food stuffs as well as to interpret the data in the light of the archaeological and social historical context."

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In your coverage please use this URL to provide access to the freely available article in PLOS ONE: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0229398

Citation: Knipper C, Rihuete-Herrada C, Voltas J, Held P, Lull V, Micó R, et al. (2020) Reconstructing Bronze Age diets and farming strategies at the early Bronze Age sites of La Bastida and Gatas (southeast Iberia) using stable isotope analysis. PLoS ONE 15(3): e0229398. https://doi.org/10.1371/journal.pone.0229398

Funding: CRH, RM, VL and RR received financial support from the Ministry of Economy and Competitiveness, Spain (grant numbers: HAR2014-53860-P and HAR2017-85962-P; URL: https://sede.micinn.gob.es/) and Direcció General de Recerca (grant number: 2017SGR1044; URL: http://agaur.gencat.cat/ca/beques-i-ajuts/). KWA received financial support from the German Research Foundation (grant number: AL 287/14-1; URL: https://www.dfg.de/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.

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