Some of Brazil’s most important rivers, including the Xingu, Tocantins, Araguaia, São Francisco, Parnaíba, Gurupi, Jequitinhonha, Paraná and Paraguay, rise in the Cerrado, the only savanna in the world with perennial rivers. This biome is at risk owing to rapid conversion to pasture and cropland, in conjunction with inadequate management of preserved areas, despite its tremendous importance as a natural resource to a country with the world’s third-largest technically usable hydroelectric potential and where hydropower accounts for 77.2 percent of the total supply of electricity.