Localised land-use and maize agriculture by the pre-Columbian Casarabe Culture in Lowland Bolivia

Multiple pre-Columbian (pre-1492 CE) archaeological sites now challenge the traditional portrayal of Amazonia as a ‘pristine wilderness’. This is especially true within the forest-savanna mosaic landscapes of lowland Bolivia, where the pre-Columbian Casarabe Culture constructed hundreds of settlement mounds, integrated with a dense causeway-canal network – one of the most complex, stratified societies yet discovered in Amazonia. Excavations at previous sites indicate that this culture sustained itself by practicing large-scale, maize-based agriculture. However, the Casarabe Culture’s mounds have also been found within the riparian forests abutting major river systems, where their inhabitants could have benefitted from greater access to forest resources and local fish species. To determine whether these differences influenced how the Casarabe Culture utilised the landscape, we conducted palaeoecological analysis on the sediments collected from Laguna Loma Suarez (LLS), an oxbow lake situated adjacent to a monumental habitation mound within these riparian forests. Our analysis reveals that, despite significant differences in natural resource availability, the Casarabe Culture continued to cultivate maize locally around LLS for over a millennium, between 280 BCE and 1130 CE, with anthropogenic fires largely restricted to the open savannas. Our record also suggests that the Casarabe Culture possibly delayed either forest recovery or natural forest encroachment until after the nearby settlement mound was abandoned. These findings, when compared with those of other sites in the region, show that maize was an important crop in pre-Columbian times, irrespective of major differences in natural resource availability across the complex forest-savanna mosaic settings of Amazonian Bolivia.