MADRID, 14 (EUROPA PRESS)
The inhabitants of the 'Lost City of the Amazon' in Ecuador's Upano River Valley cultivated maize and planted alder trees for more than 1,200 years, but a subsequent occupation, lasting just 300 years, transformed the forest's ecology.
A new study led by Florida Tech Professor Mark Bush and University of Amsterdam Professor Crystal McMichael used microfossils extracted from the sediment of Cormorant Lake to provide the first detailed, 2,700-year view of the changing landscapes of the Upano River Valley. The findings are published in Nature Communications.
Their work builds on existing archaeological studies that have documented more than 7,000 structures hidden in the forests of the Upano Valley, which some researchers have described as the Lost City of the Amazon.
"Our study provides an improved chronology of human activity in the valley, as we observe the movement of people in and out of the landscape and the movement of different farming styles," said Bush, who directs Florida Tech's Global Ecology Institute.
DISAPPEARED AROUND THE 6TH CENTURY AD
Around 750 BC, the Upano civilization began to occupy the valley. By 250 AD, its influence in the area began to weaken before disappearing around 550 AD. The authors refute the existing idea that a massive ash fall from Sangay Volcano caused the abandonment, and conclude that it was a gradual decline over several hundred years.
After abandonment, the forest closed in on traces of human presence until a new wave of occupants arrived around 1500 AD. These people cultivated maize until they too abandoned the land around 1800 AD. The forest that recovered after this abandonment was rich in tall palm trees, creating a type of forest that had not been seen in the previous millennia.
The authors conclude that a combination of climate change and human impact has shaped the current forests of the Upano River Valley and that, although these forests appear natural, they have only existed in their current form for about 200 years.
