Supposedly pristine South American forest had been pre-Columbian farmland

Enlarge / Lake Huila records centuries of environmental change in the Quijos Valley. (credit: Nicholas Laughlin)

On the slopes of northern Ecuador's Quijo Valley, perpetual clouds shroud the canopy of a seemingly pristine tropical forest. But the beauty of the cloud forest hides a violent, tragic history. A new study of sediments from the valley's Lake Huila reveals centuries of indigenous agriculture that came to an abrupt end in warfare and fire around 1588.

Population collapse

From about 1400 to 1532, the Quijos Valley marked the eastern frontier of the Incan Empire. Although they were subjects of the empire, the people of the Quijos Valley maintained a distinct cultural identity from the Incas, and historical and archaeological records show that the valley was a conduit for trade between Incan territory and the peoples of the Amazon Basin.

The first Europeans to set foot in the Quijos Valley were Spanish expeditions in 1538 and 1541, who arrived in search of gold and cinnamon. They estimated that about 35,000 indigenous people lived in the region. By 1577, about 11,400 people had clustered around the Spanish town of Baeza, which the colonizers built in 1559 alongside the indigenous community of Hatunquijos. But by 1600, three out of four of these people were dead.