Tracing 4000 years of environmental history in the Cuzco area, Peru, from the pollen record

The Central Peruvian Andes stand out as a globally important center of cultural and biological evolution. This is supported by its location at the heart of the former dominating Inca civilization (AD 1440-1534), itself built on remarkable preceding civilizations. These civilizations have arisen in this area possibly because of its exceptional natural biodiversity and its prominence as a center of domestication for numerous high altitude crops growing between 2000-4500 m a.s.l. Continuous environmental records for the Holocene from lake basin deposits in the Cuzco area would provide valuable information on how early human impact occurred. They would also assist in determining when the transition to agriculture took place in the southern highlands of present day Peru. A pollen record from Marcacocha, an in-filled lake basin at 3300 m near Ollantaytambo indicates evidence of a deforested agricultural landscape earlier than 4000 years ago. Major local climatic events at about AD 100 and 1050 in the record separate three contrasting land-use phases and may be linked to climatic events of a wider geographical occurrence. Most importantly these data furnish valuable insight into which cultures in Peru appeared to manage these fragile mountainous environments with minimal impact, and even evidence of agro-forestry using Alnus on a major scale. These are numerous lakes in the Cuzco area to provide a complete regional overview. A selection of these sites is presented. It is suggested that a series of continuous records at different altitudes may fill the gaps in our understanding of the composition of natural vegetation communities, including the distribution of Polylepis forest in existence prior to human impact. All this information will be important to agronomists, archaeologists, ecologists, and palaeoclimatologists alike.