Humans settled in southwestern Amazonia and even experimented with agriculture much earlier than previously thought, according to an international team of researchers.

"We have long been aware that complex societies emerged in Llanos de Moxos in southwestern Amazonia, Bolivia, around 2,500 years ago, but our new evidence suggests that humans first settled in the region up to 10,000 years ago during the early Holocene period," said Jose Capriles, assistant professor of anthropology. "These groups of people were hunter gatherers; however, our data show that they were beginning to deplete their local resources and establish territorial behaviors, perhaps driving them to begin domesticating plants such as sweet potatoes, cassava, peanuts and chili peppers as a way to acquire food."

The archaeological team conducted its study on three forest islands—Isla del Tesoro, La Chacra and San Pablo—within the seasonally flooded savanna of the Llanos de Moxos in northern Bolivia.1

  • 1. Source: Pennsylvania State University vie phys.org

Persistent Early to Middle Holocene tropical foraging in southwestern Amazonia

José M. Capriles, Umberto Lombardo, Blaine Maley, Carlos Zuna, Heinz Veit and Douglas J. Kennett

Science Advances  24 Apr 2019:
Vol. 5, no. 4, eaav5449
DOI: 10.1126/sciadv.aav5449

Abstract: The Amazon witnessed the emergence of complex societies after 2500 years ago that altered tropical landscapes through intensive agriculture and managed aquatic systems. However, very little is known about the context and conditions that preceded these social and environmental transformations. Here, we demonstrate that forest islands in the Llanos de Moxos of southwestern Amazonia contain human burials and represent the earliest settlements in the region between 10,600 and 4000 years ago. These archaeological sites and their contents represent the earliest evidence of communities that experienced conditions conducive to engaging with food production such as environmental stability, resource disturbance, and increased territoriality in the Amazonian tropical lowlands.

Fig. 3 Stratigraphy of cores and excavations carried out at SM4.
Fig. 3 Stratigraphy of cores and excavations carried out at SM4. - SM4 is placed above fluvial sands that overlay clay deposits (A). Both the sand and clay show high levels of hydromorphism: red and yellow staining due to the formation of iron oxides. These hydromorphic conditions are typical of tropical soils subjected to repeated cycles of humid and dry conditions, as it happens in regions with strong seasonality. However, currently, these sediments are found below a wetland (B), suggesting that these iron oxides are a relict feature of the past, when the average water table was meters below its current depth. A view from the north (C) shows how today the forest island is surrounded by tall marsh vegetation and connected to the mainland by a modern causeway. Photo credits: (B) Source image: DigitalGlobe, Google Earth, and (C) José M. Capriles, PSU.