The legacy of 4,500 years of polyculture agroforestry in the eastern Amazon, Maezumi et al. 2018

This study combines archaeology, archaeobotany, palaeoecology and palaeoclimate investigation to shed light on the legacy of pre-Columbian land management practices on today’s Amazon rainforest. Evidence points to a millennial-scale cultivation practice that at once maintained ecosystem integrity while sustaining a large and growing human civilization.

Here, we show that persistent anthropogenic landscapes for the past 4,500 years have had an enduring legacy on the hyperdominance of edible plants in modern forests in the eastern Amazon. We found an abrupt enrichment of edible plant species in fossil lake and terrestrial records associated with pre-Columbian occupation. Our results demonstrate that, through closed-canopy forest enrichment, limited clearing for crop cultivation and low-severity fire management, long-term food security was attained despite climate and social changes. Our results suggest that, in the eastern Amazon, the subsistence basis for the development of complex societies began ~4,500 years ago with the adoption of polyculture agroforestry, combining the cultivation of multiple annual crops with the progressive enrichment of edible forest species and the exploitation of aquatic resources. This subsistence strategy intensified with the later development of Amazonian dark earths, enabling the expansion of maize cultivation to the Belterra Plateau, providing a food production system that sustained growing human populations in the eastern Amazon. Furthermore, these millennial-scale polyculture agroforestry systems have an enduring legacy on the hyperdominance of edible plants in modern forests in the eastern Amazon. Together, our data provide a long-term example of past anthropogenic land use that can inform management and conservation efforts in modern Amazonian ecosystems [Maezumi 2018: 540].

This largely hidden history of the Amazon illuminates a path forward today as humanity grapples with the combined challenges of maintaining food production for a growing global population, while preserving and restoring forests and curbing biodiversity collapse. As suggested here, ecological restoration and agricultural productivity to sustain growing populations are not mutually exclusive enterprises, but in fact can be synergistic.