Río Pilcomayo

Río Pilcomayo National Park was created in 1951 in the north of Formosa province, on the right bank of the river that gives it its name and that marks the border with Paraguay, and protects some 470 km².

It preserves a representative sample of the eastern humid Chaco, a mosaic of permanent or seasonal marshes and channels, caranday palm groves, flooded grassland, islands of woodland and gallery forest along the watercourses. Laguna Blanca, of some seven hundred hectares, is the main body of water and the focus of the park's wildlife.

Its fauna includes emblematic Chaco species: the maned wolf, the largest canid in South America, the giant anteater, the giant armadillo, the marsh deer and the broad-snouted caiman, as well as an abundant waterbird fauna with southern screamers, storks and herons. The park was designated a Ramsar site in 1992. Its main threat is the alteration of the water regime of the Pilcomayo, a river of exceptional behaviour that loses its defined channel and silts up upstream, which has profoundly changed the water supply to the marshes.