 Below Alto Purus on the Piedras River is the Reserva Territorial Madre de Dios, which is the official territory of Masco-Piro indigenous people, who have been living in voluntary isolation since at least the time of the rubber boom that began in the 1860s.Downriver from the Reserva Territorial Madre de Dios are commercial timber concessions and the indigenous territories of Monte Salvado and Puerto Nuevo.Below the timber concessions and indigenous communities are Brazil nut concessions and several small indigenous and mestizo communities, including the mestizo communities of Lucerna and Sabaluyoc.