THE WARI OCCUPATION IN THE VALLEYS OF PALPA, PERU SOUTH COAST

Recientes investigaciones en los valles de Palpa, en la parte norte de la cuenca del Río Grande de Nasca, han puesto al descubierto numerosas evidencias arqueológicas (asentamientos, estructuras funerarias, diversos materiales y restos de la vida cotidiana) que están brindando nuevas luces sobre la intensidad y la naturaleza que tuvo la ocupación Wari en la costa sur del Perú. Excavaciones puntuales realizadas en varios sitios con evidencias de ocupación Wari en los valles de Palpa, los cuales están localizados en la costa, la yunga desértica y la sierra, nos ayudan a entender el fuerte grado de integración existente entre diferentes zonas ecológicas y el interés que tuvieron los Wari para ocupar los valles de Palpa y Nasca. En este sentido, las evidencias documentadas hasta hoy en los valles de Palpa indican que la costa sur, y de modo especial la cuenca del Río Grande, tuvo un rol importante en el desarrollo de las estrategias de expansión y control de Wari en la región, lo que le permitió el acceso a recursos no existentes en la zona de Ayacucho.Recent research in the Palpa valleys, in the northern section of the Rio Grande of Nasca drainage, has revealed many archaeological evidences (settlements, funerary structures, diverse materials and remains of daily life). This evidence is shedding new light on the intensity and nature of the Wari occupation in the south coast of Peru. Excavations in many sites with evidence of Wari occupation in the coast, the Yunga Desertica, and the highlands, help us to understand the strong integration that existed amongst different ecological zones and the interest that motivated the Wari to occupy the Palpa and Nasca valleys. In this context, the evidence registered until now in the Palpa valleys indicated that the south coast, and specially the Rio Grande drainage, had an important role in the Wari strategy of expansion and control in the region, allowing the access to resources not existent in the Ayacucho area

Climate change underlies global demographic, genetic, and cultural transitions in pre-Columbian southern Peru

Several archaeological studies in the Central Andes have pointed at the temporal coincidence of climatic fluctuations (both long- and short-term) and episodes of cultural transition and changes of socioeconomic structures throughout the pre-Columbian period. Although most scholars explain the connection between environmental and cultural changes by the impact of climatic alterations on the capacities of the ecosystems inhabited by pre-Columbian cultures, direct evidence for assumed demographic consequences is missing so far. In this study, we address directly the impact of climatic changes on the spatial population dynamics of the Central Andes. We use a large dataset of pre-Columbian mitochondrial DNA sequences from the northern Rio Grande de Nasca drainage (RGND) in southern Peru, dating from similar to 840 BC to 1450 AD. Alternative demographic scenarios are tested using Bayesian serial coalescent simulations in an approximate Bayesian computational framework. Our results indicate migrations from the lower coastal valleys of southern Peru into the Andean highlands coincident with increasing climate variability at the end of the Nasca culture at similar to 640 AD. We also find support for a back-migration from the highlands to the coast coincident with droughts in the southeastern Andean highlands and improvement of climatic conditions on the coast after the decline of the Wari and Tiwanaku empires (similar to 1200 AD), leading to a genetic homogenization in the RGND and probably southern Peru as a whole