Horticulturists and oxygen ecozones in the tropical and subtropical forests of Southeast South America

Abstract

We analyse the isotopic values (δ¹³C, δ¹⁵N) of the diet of pre-Columbian horticulturalist populations from tropical and subtropical areas of southeastern South America, belonging to the Guarani and Taquara archaeological units. The data indicate different trends in each one (T = 4.21; P = 0.0004), showing a mixed diet with maize consumption in the Guarani samples (δ¹³C_co = −15.5 ± 1.8‰; δ¹³C_ap −10.4 ± 0.8‰) and a depleted one in the Taquara ones (δ¹³C_co −18.2 ± 1.7‰; δ¹³C_ap −11.9 ± 0.9‰), with a significant internal dispersion in both populations. The first population has higher nitrogen values (δ¹⁵N 11.1 ± 0.6‰) compared to the Taquara samples (δ¹⁵N 9.3 ± 1‰), suggesting a more carnivorous diet. The recognition of these pre-Columbian mixed diets involves the identification of maize cultivation on the Atlantic side of the southernmost area of South America (Parana Delta, 34° SL). Through the analysis of δ¹⁸O we have identified two isotopic ecozones, the first along the Paraná River Valley, with an average value of δ¹⁸O −3.7 ± 0.5‰ (CV = 13.5%; CI = −3.83 / −3.16), and the second one, located in the Planalto of southern Brazil (Araucaria Forest), with a mean value of δ¹⁸O −1.5 ± 0.3‰ (CV = 16.5%; CI = −1.69 / −1.29). The isotopic data (δ¹³C, δ¹⁵N and δ¹⁸O) suggest human movements between these two ecozones.

Keywords:

• Carbon
• Nitrogen
• Oxygen
• Isotopes
• South America
• Horticulturalists
• Maize
• Guarani
• Taquara

Acknowledgements

This work would not have been possible without the contribution of Jairo Rogge and Pedro Ignacio Schmitz, who sent us the samples recovered from the Abrigo do Matemático site. We are also indebted to Christian Gates, who provided valuable opinions and helped us with the English translation. Francisco Cruz and Hector Panarello gave us significant opinions and bibliography. We would like to thank the four reviewers for their comments. Tim Mighall gave us a great help throughout the editorial process. The field work in the Corpus and 3 de Mayo Cave was made possible with the support of the Corpus and Garuhapé County governments, respectively. This research was funded by the National Agency for Scientific Promotion (PICT 2011-2035), CONICET (PIP 11220110100565), the Universidade da Região Comunitária de Chapecó (Santa Catarina, Brazil), and the National Institute of Anthropology of Argentina. This project is also implemented with the support of the State of Santa Catarina, the Department of Tourism, Culture, and Sport, the Santa Catarina Culture Foundation, FUNCULTURAL and the Elisabete Anderle Grant/2014. The ideas expressed are the sole responsibility of the authors.

ORCiD

Daniel Loponte http://orcid.org/0000-0002-3826-5595