Where we pass, we leave our mark, we change the landscape. Even what we consider a pristine paradise, the Amazon forests, not yet tainted by economic interests, have already been transformed by the first humans who inhabited them 10,000 years ago. And in a formidable way, as suggested by an international study in which the Pompeu Fabra University has participated. Researchers have discovered that these first inhabitants created 4,700 artificial mounds in the middle of the Bolivian Amazon savanna in which they cultivated wild plants such as cassava and squash for their consumption. The results appear published in the journal «Nature».
The discovery of these “forest islands” has occurred in what is now Llanos de Moxos, in northern Bolivia, a savanna area that floods from December to March and is extremely dry from July to October. However, the mounds remain above water level during the rainy season and allow trees to grow. Were they done that way on purpose, so the crops wouldn’t get flooded? Javier Ruiz-Pérez, from the Humanities department of the Pompeu Fabra and co-author of the article, believes that it is a possibility, although he acknowledges that the reasons and the way in which these artificial areas were built “are not yet known exactly.”
“They probably formed as a result of the inadvertent accumulation of waste (for example, remains of gastropod shells after consumption) and activities they carried out in the settlement, such as burning organic matter,” explains the researcher in an email. to ABC. “But we also cannot rule out the possibility that they intentionally accumulated sediment or even that it is a combination of both scenarios. The mounds could offer protection against floods during the wet season and were ideal spaces for farming while hunting and gathering outside the ‘islands’, ”he argues.
The study consisted of an unprecedented large-scale regional analysis of 61 archaeological sites, previously identified by satellite, now patches of forest surrounded by savanna. Samples were recovered from 30 forest islands and archaeological excavations were carried out on four of them.
Cassava, pumpkin and corn
Using well-preserved plant silicified cells, called phytoliths, which are well preserved in tropical forests, experts documented in the mounds the first evidence found in the Amazon of cassava (10,350 years ago), squash (10,250 years ago) and corn (ago 6,850 years).
The authors believe that these plants were chosen because they were rich in carbohydrates and easy to cook, and they probably provided a considerable part of the calories consumed by the first inhabitants of the region, who also fed on fish, some meat and fruits obtained by harvesting.
Many important crops such as cassava, squash, peanuts, some varieties of chili and jackbean are genetically very close to wild plants that live in the Amazon, so scientists already suspected that this area could be one of the first places in the world where plants were domesticated. However, until now this theory has not been documented with archaeological findings.
Now, finally, the new research places the Amazon as the fifth area in the world where humans first domesticated vegetables about 11,000 years ago. The other four are found in China (millet minor, rice), the Middle East (wheat, barley), southwestern Mexico (corn), and northwestern South America (squash).
Although little is known about the origin of the first settlers of the southwestern Amazon, the evidence found shows that they formed itinerant or semi-itinerant groups that were not only hunters and gatherers, but colonizers that considerably modified the landscape by constructing mounds where they grew plants.