Stable isotope analysis of a pre-Hispanic Andean community: Reconstructing pre-Wari and Wari era diets in the hinterland of the Wari empire, Peru

Objectives: Stable carbon and nitrogen isotope analysis is used to reconstruct diet among a pre-Hispanic population from the Peruvian Andes to evaluate whether local foodways changed with Wari imperial influence in the region. This study also compares local diet to other Wari-era sites. Materials and methods: Samples derive from the site of Beringa in Peru and correspond primarily to pre-Wari (200–600 CE) and Wari (600–1,000 CE). We examine stable carbon isotopes from enamel (n = 29) and bone apatite (n = 22), and stable carbon and nitrogen isotopes from bone collagen (n = 29), and we present stable carbon and nitrogen isotope data on archaeological and modern fauna (n = 37) and plants (n = 19) from the region. Results: There were no significant differences in either δ¹³C or δ¹⁵N from the pre-Wari to Wari era, indicating that those measurable aspects of diet did not change with Wari influence. There were no sex-based differences among juveniles (as inferred from δ¹³C from enamel carbonates) nor among adults (based on δ¹³C and δ¹⁵N from adult bone collagen). Comparisons to other Wari era sites show that Beringa individuals exhibited significantly lower δ¹³C values, suggesting that they consumed significantly less maize, a socially valued food. Further, the Froehle et al. (2012) stable isotope model suggests that the majority of the Beringa individuals consumed more C₃ than C₄ plants, and dietary protein was derived primarily from terrestrial animals and some marine resources. Conclusions: The similar diets from pre-Wari to Wari times hint at strong local dietary traditions and durable food trade networks during the period of Wari imperial influence. The presence of limited marine foods in the diet suggests a trade network with coastal groups or sojourns to the coast to gather marine resources.