After two years of research, the PACHAMAMA project is providing significant new data on the role of marine resources and plant-based diets in urban development on the PNCC and the Central Andes as a whole. Results indicate that the main source of dietary calories of the earliest PNCC urban centers were plants from the C3 photosynthetic pathway such as tubers, legumes, and fruits, even among coastal sites where protein intake derived primarily from marine resources. This trend, initiated at least 3000 years BCE, continued until the mid-first millennium BCE, when diets based on C3 plants gradually shifted to include C4 plants. Given that only two C4 species —amaranth and maize— were consumed in this region, the isotopic data from the latter half of the first millennium BCE and beyond (i.e. the Early Intermediate Period dated 1-600 CE), can reliably be attributed to maize. Additionally, climatic oscillations associated with the El Niño Southern Oscilation , which produced lower sea surface temperatures and increased marine productivity alongside declines in inland agricultural yields, appear to have significantly influenced dietary adaptations across different periods. Strontium and Oxygen isotopes, used to understand mobility patterns, yielded valuable insights into the movement of people across the PNCC and other areas of the Peruvian Central Coast.
In sum, PACHAMAMA project has successfully generated robust isotopic data that deepen our understanding of diet and social organization in early Andean urban centers, allowing us to trace dietary changes over time and reveal the economic foundations of early Andean civilization. After approximately 50 years of debate, it is now evident that the development of Andean civilization, including the earliest urban centers of the PNCC, was grounded in plant cultivation, complemented by marine protein where ecological and climatic conditions permitted. This agricultural development involved highly adapted practices suited to arid conditions, alongside high-risk farming characterized by sophisticated land and water management underpinned by a strong ideological system, a pattern widely supported for Formative-period populations in the Central Andes.
