Environmental changes in the highlands of the western Andean Cordillera, southern Peru, during the Holocene

Abstract

In the tropical Andes, impacts of both natural and anthropogenic disturbances have been detected over a period exceeding 4000 years. However, the history of the environment remains unknown in most Andean regions. To infer possible interactions between climate and humans, we analysed the pollen content of an 8.5 m deep peat core extracted from a peat bog located near the Nevado Coropuna volcano on the slope of the Western Cordillera in southern Peru (15°30S, 72°40W, 6380 m). Results showed that taxa of the upper Puna expanded when cooler and moister climatic conditions prevailed during a time period that includes the early and the mid Holocene (9700–5200 cal. yr BP). An increase in shrub pollen frequencies and a decrease in the Poaceae/Asteraceae ratio are attributed to a drier climate during the late Holocene (5200–3000 cal. yr BP). After 3000 cal. yr BP, the vegetation cover resembled that of today. Both archaeological and pollen data attest to the beginning of agriculture from 2200 cal. yr BP. Around 900 cal. yr BP, the vegetation cover suddenly changed, probably because of a colder and drier climate. Past societies continued their agricultural activities despite this abrupt change. Our results emphasize the specific geographical location of Nevado Coropuna astride the Western Cordillera and the western edge of the Altiplano, which is consequently subject to both Pacific and Atlantic influences.

Prospecting Glacial Ages and Paleoclimatic Reconstructions Northeastward of Nevado Coropuna (16° S, 73° W, 6377 m), Arid Tropical Andes

“…However, pollen within the Coropuna glaciers reveal different air masses fluxes. Herreros et al [59] drilled an ice core at 6080 m altitude, on the Coropuna northern slope, identifying pollen taxa that currently do not exist in that volcanic complex [60,61]: -Quercus and Podocarpus: from the Amazon basin, ~300 km northeastward. -Nothofagus: native of Patagonia, >3000 km toward the south.…”

The Medieval Climate Anomaly and the Little Ice Age in the eastern Ecuadorian Andes

“…Continuous terrestrial records over the last millennium are still rare in the Andes. In southern Peru, a pollen record confirmed the presence of a sustained drought between 900 AD and the early 17th century (Chepstow-Lusty et al, 2009) that allowed the Incas to expand their Andean territory due to their ability to use new drought-adapted agricultural practices up to high elevations (Kuentz et al, 2012). Recently, tree-ring climate reconstructions of the last 700 yr from the central Andes also revealed a persistent drought from the 14th to the 16th century and a return to wetter conditions at the beginning of the 17th century, which was then again followed by another long-term drought (Morales et al, 2012).…”

El surgimiento del paisaje monumentalizado pensado desde los datos de la cuenca del lago Titicaca, Andes Centro-Sur

“…Esto es una muestra de una distinta relación del ser humano con la producción y reproducción de su paisaje, cuando los aldeanos empezaron a desherbar sus chacras y deshacerse de la quinua negra, para quedarse solo con el Chenopodium quinua (Bruno 2008), clara evidencia de especialización de la domesticación de este especie y el inicio de la agricultura como tal, en la región. Esta fecha también concuerda con los rastros de huella ecológica que la sociedad empezó a impregnar en el paisaje puneño (Kuentz et al 2012;Paduano et al 2003).…”