At midday on the road into Grünland, a Mennonite colony in the Bolivian department of Beni, the only sound is a distant chainsaw.
On either side, strips of deforested land extend into the distance. Underfoot, the soil is scattered with shards of ceramic and bone: remnants of the pre-Columbian peoples that this part of the Bolivian Amazon, known as the Llanos de Mojos, once supported.
Archaeologists are only just beginning to understand the scale and complexity of these societies, but all the while, the agricultural frontier keeps advancing, destroying sites before they can be studied. The environmental damage of deforestation is well-known, but the Llanos de Mojos reveals another side of its impact: the loss of human history.
Grünland was founded in 2005 by Mennonites, members of the tightly-nit Anabaptist Christian group that began arriving in South America in the early 20th century, in search of isolation and lands to cultivate.
In one field, a Mennonite man called Guillermo was resting in the shade of his tractor. He cheerfully acknowledged finding ceramics and bones while working the land.
Umberto Lombardo, an Italian earth scientist and one of a handful of academics who study the archaeology of Beni, probed gently with questions about the topography of the land when it was first deforested.
The Llanos de Mojos is an almost completely flat region, so any elevated areas are a sure sign of human activity. Lombardo walked about, stopping here and there to pick pieces from the earth of what was once a vast human-made mound, now partly flattened by the farmers.
“The surface of the site is completely destroyed, changed, because the earth has been moved, the pottery broken,” said Lombardo. “That part of the archaeological archive is lost.”
The Mennonites are just one facet of Bolivia’s booming agribusiness, and what is happening in Grünland is happening all over Beni.
The Bolivian government has big plans for the sector. Today, the country has roughly 4m hectares of cultivated land and 10 million cattle. By 2025, the government wants 13m hectares and 18 million cattle.
On the current trajectory the government will undershoot those targets substantially. Nonetheless it has boosted the sector’s growth by allowing more deforestation and reducing fines for illegal deforestation.
In 2021, Global Forest Watch placed Bolivia third in the world for loss of primary forest, behind Brazil and the Democratic Republic of Congo. Ranked by population, Bolivia is first by a distance.
Most of this deforestation is happening in two departments: Santa Cruz and Beni. But it is in Beni that a unique archaeological heritage is at risk.
“Archaeology is everywhere in Beni,” said Lombardo. “They say if you put up a roof, you have a museum.”
The Amazon basin was once considered to be pristine wilderness, but a growing body of research has found traces of a vast network of earthworks predating the arrival of Christopher Columbus in the Americas and implying the existence of large, complex societies.
In Bolivia the archaeologist Heiko Prümers and his team began flying over the Llanos de Mojos by helicopter in 2019, mapping the land beneath them with a laser. They then digitally stripped away the vegetation, revealing the topography of the ground underneath.
In a paper published in Nature, they described settlements built around monumental mounds, some 20 metres high. Smaller settlements surrounded the larger ones, linked by causeways running for kilometres. Canals and reservoirs show how the people shaped the land for agriculture.
It’s no accident that archaeology and agribusiness coincide in Beni: the pre-Columbian earthworks that made agriculture possible then continue to function today.
“The landscape that we have today is the result of pre-Columbian intervention,” said Lombardo. “The legacy remains – and farmers make the most of it.”
For most of the people that live here and work the land – whether Indigenous communities, settlers, Mennonites or agribusiness – the archaeological remains are so common they are barely remarked on, much less preserved.
Roads slice through monumental mounds. Farmers flatten them. People build huts on top of them. In one case near the Mennonite colony, the state road company was taking earth from a mound to fill in potholes.
“For most people here, these mounds don’t have any special value,” said Lombardo. “They know that there are bones and pottery in the earth, but they see them as part of the natural landscape.”
Even if they did know the value of the sites, there are no incentives for people to report them to the state – nor any experts that could readily be sent to study them. There are just a handful of archaeologists studying the Llanos de Mojos, and none lives in Bolivia.
“The gap between the wealth of archaeology and the human capital available to study it – it’s an abyss,” said Lombardo.
In an ideal world, he says, the government would educate locals about the importance of the mounds, pay to preserve them and set up an archaeological faculty in Beni.
For now, Lombardo takes a pragmatic view: archaeologists need to salvage what they can. “It’s utopian to think you can protect all the archaeology here: it would mean nobody doing anything.”
On the way back from Grünland, Lombardo encountered a local Indigenous man he knew, Bernardo, trying to kickstart his motorbike. They got talking. Bernardo mentioned another mound, in the forest, not far from the road.
Lombardo followed him in, swiping at vines with a machete, lifting his feet high to avoid tripping on roots. A path appeared – a pre-Columbian causeway, said Lombardo, over his shoulder – and rose, gradually, to an overgrown mound perhaps six metres high.
In the middle there was a gaping hole. Bernardo said it was dug by locals looking for gold. The mosquitoes began to gather round.
“There are so many things to study,” said Lombardo, in a moment of melancholy, on the edge of the crater. “If these sites are destroyed, we may never have the answers.”