Primitive people did not live in harmony with nature, scientists say

A study of food remains from ancient sites along the lower Ica River in Peru has confirmed earlier suggestions that even early humans did not live in harmony with nature.

Researchers from the University of Cambridge (UK) and their colleagues analyzed food waste covering the period from 750 BC to 900 AD and found that in less than two thousand years, the valley's inhabitants went through three stages: first they were gatherers, then they devoted themselves to agriculture, after which they partially returned to gatherers again.

This supports the hypothesis that by removing too much natural vegetation to make room for crops, ancient farmers unwittingly contributed to flooding and erosion, which eventually caused a shortage of farmable land. “Farmers had inadvertently crossed a threshold where the ecological changes became irreversible,” says study author David Beresford-Jones.

Today it is a barren wasteland, but the remains of huarango trees and patches of loosened soil suggest that this was not always the case. Previous work by the same team has already shown that this was once an area of highly developed agriculture.

Scientists have taken samples of middens and washed out the sediment, leaving behind a mix of plant and animal remains. The earliest ones show no evidence of domesticated crops. People ate snails, sea urchins, and mussels collected from the Pacific coast, an eight-hour walk to the west. Samples from the last centuries BCE begin to show pumpkin seeds, cassava tubers, and corn cobs, and a few hundred years later there is evidence of agriculture, with a wide range of crops including corn, beans, squash, peanuts, and peppers. But 500 years later, the story has returned to normal: the middens are once again full of sea and land snails, mixed with wild plants.

Farming here would not have been possible without the huarango forest, which formed a physical barrier between the ocean and the valley and kept the soil fertile by fixing nitrogen and water. But as more land was needed to grow crops, more forest was destroyed, until the balance was lost forever. The valley was exposed to El Niño, floods, and erosion. Irrigation canals were destroyed, and piercing winds blew.

An indirect witness to this sad story is the indigo bush, which produces an intense blue dye. The seeds of this plant are a frequent find in early Nazca settlements (100–400 CE). Textiles from this period are easily recognizable by their generous use of the characteristic dye. In later periods, the deficiency of the dye becomes obvious. Since indigo grows in the forest shade along watercourses, the disappearance of the bush suggests that the same thing happened to the forest.

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