Amazonian Dark Earths in Western Amazonia?

Western Amazonia is a large region that includes a global biodiversity hotspot (the Yasuni National Park) and which still retains large tracts of intact native rainforest. Along the Napo River (Fig. 1), which originates in the Ecuadorian eastern lowlands and discharges into the Peruvian reaches of the Amazon River, current human settlement is uneven and highly dispersed. In Ecuador, towns are associated with the encroachment of oil extraction activities and the expansion of the agricultural frontier; small villages are found along an expanding road network and also dot the banks of the main rivers; and small groups of nomadic peoples, some in voluntary isolation from our industrialised society, inhabit the rugged interfluvial terrain beyond the main rivers. In Peru, small villages dot the middle reaches of the Napo River and its main tributaries, and there are also reports of indigenous groups in voluntary isolation. Larger settlements become more prevalent in the lower Napo, closer to the Amazon River and within reach of the road network leading to the Peruvian city of Iquitos