In this chapter, the Western Amazon refers to the basins of the Caquetá-Japurá, Putumayo-Içá, Napo, Marañón, Ucayali, Juruá, and Purus rivers. Together, they account for approximately 40% of the water discharge and approximately 70% of the sediment load of the mainstem Amazon. Rivers of the Western Amazon pass through at least 12 ecoregions, from the peak of Huascarán mountain (6770ma.s.l.) to the Juruá-Purus moist forest ecoregion (20-60ma.s.l.). These rivers run through Bolivia, Brazil, Colombia, Ecuador, and Perú, and nourish regions of vast biological and cultural diversity. While the main land use in the Western Amazon is favorable for conservation (for example, protected areas and Indigenous territories), economic activities broadly in the Western Amazon have been historically determined by boom and bust cycles. Currently, the boom is represented by extractive industries that focus on hydrocarbons, illicit crops, commercial fisheries, and gold mining.
