
PhysOrg reports:
Archaeologists examining the remains of the Nasca, who once flourished in the valleys of south coastal Peru, have uncovered a sequence of human-induced events which led to their "catastrophic" collapse around 500 AD.
Using plant remains gathered in the lower Ica Valley, the team found evidence that over the course of many generations, the Nasca cleared areas of forest to make way for their own agriculture. Studies of pollen samples taken by co-researcher Alex Chepstow-Lusty, of the French Institute of Andean Studies in Lima, showed that the huarango tree, which once covered what is now a desert area, was gradually replaced by crops such as cotton and maize.
As the paper explains, however, the huarango was more than just a tree - it was a crucial part of the desert's fragile ecosystem, which enhanced soil fertility and moisture and helped to hold the Nasca's narrow, vulnerable irrigation channels in place. READ MORE