Pre-Columbian land use and its modern legacy in the Purus-Madeira Interfluve, Central Amazonia

Abstract

To combat environmental degradation and change, it is imperative that the rainforests are protected and sustainable land use practices are developed in Amazonia. A better understanding of the role of humans in shaping Amazonian environments and the extent to which the forests have been resilient to anthropogenic disturbance is critical to determining the current state of these ecosystems. This research provides the first reconstruction of late pre-Columbian to early post-Columbian land use and its environmental legacy in the Purus-Madeira Interfluve, Central Amazonia. Soil profile samples were collected across a transect approximately 600 km in length between Manaus and Humaitá, covering a large ecological gradient from dense canopy forests to open canopy forests, as well as dry, upland areas (terra firme) and small riverine settings. Archaeobotanical phytolith and terrestrial palaeoecological samples were analysed from four contexts: (i) primary forests; (ii) oligarchic forests dominated by economically useful trees in the terra firme rainforest on natural soils; (iii) an anthropogenic forest with Brazil nut trees on anthropogenic soil; and (iv) a previously undocumented archaeological site next to the Brazil nut stand. The outcome of this study provides evidence that the extent of the preColumbian environmental impact was larger than previously thought, and this shows that humans managed these forests in various ways to varying intensities. The data, therefore, helps to identify the long-term role of human-environment interactions in Central Amazonia and provides valuable information for future environmental and land use regulation policies.