The Man and Biosphere Programme (MAB) of UNESCO declared Pilon Lajas a Biosphere Reserve in 1977. Since that international recognition, Pilon Lajas was the subject of increased interest from researchers and the Bolivian government. In 1992 Pilón Lajas was recognized by Supreme Decree Nº 23110 as an Indigenous Territory for the T’simane Mosetene peoples, and the Biosphere Reserve was created within the indigenous territory limits with the objective of preserving the genetic integrity of the existing fauna and flora biodiversity. In 1997, within the framework of the INRA Law (1996), the Indigenous Territory was formally submitted for land titling according to the land sanitation results. Finally, in 2007, the area was titled to the T'simane Mosetene Regional Council (CRTM), representing 24 communities (T'simane, Mosetene and Tacana) of Pilón Lajas, with a population of 1,394 inhabitants (238 families).
Pilon Lajas is located east of the La Paz Department in the Sud Yungas and Franz Tamayo provinces, and the southwest of the Beni Department in the Ballivián province, covering an area of 400,000 ha. Pilon Lajas presents a mosaic of different types of vegetation (sub Andean rainforests, mainland Amazonian forests, varzea forest of bajio and palms) within a diversity of climatic, topographic and geological conditions.
The Reserve plays a fundamental role in the conservation of species with large spatial requirements, such as the spectacled bear (Tremarctos ornatus), the jaguar (Panthera onca) and the giant otter (Pteronura brasiliensis). It also protects threatened species, including the spider monkey (Ateles chamek) and the harpy eagle (Harpy harpyja).