Fernando J. Astudillo, 2011, Phytoliths, Palaeoenvironment and Human Settlement of the Northern Ecuadorian Andes, M.A. thesis, Department of Archaeology, University of Calgary.

Absract:

Ancient agricultural terracing, middle Holocene grassland composition, weather change, and vegetation dynamics in Andean Páramos and montane forest were studied based on quantitative phytolith analysis. Palaeoecological samples from terraces were taken at the archaeological site of Palo Blanco in the highlands of northern Ecuador, which reflect the presence of permanent grass vegetation with changes in its composition. Minor changes in the frequencies of grass vegetation of the Panicoideae subfamily are related to a weather change about 3 640 BP. Human impact is observed in the modification of natural slopes creating terraces. The results indicate that the weather variation might be the cause of an early modification of the landscape, perhaps for agriculture.