Humedales Chaco. 02/02/04; Chaco; 508,000 ha.; 27°20'S 058°50'W. Covering part of the Paraná and Paraguay Rivers floodplain complex in the eastern border of Chaco province, limited to the north by the Bermejo River and surrounding the city of Resistencia. The hydrological regimes of each river give rise to different pulses of flood and drought in these wetlands, regulating floods downstream and retaining water in times of drought. The landscape is a complex of open water, aquatic vegetation, grasslands and gallery forests. Wildlife in these forests shares traits with that of the Humid Chaco and the Amazon region, and representative tree species are the "Ibira-Pitá" Peltophorum vogelianum, the "Lapacho negro" Tabebuia ipe, Nectandra falcifolia and Enterolobium contortosilquum. Several endangered species inhabit the site, including the Marsh Deer Blastocerus dichotomus, the Neotropical Otter Lutra longicaudis, the Bare-faced Curassow Crax fasciolata. Crocodilians (Caiman latirostris, C. crocodylus), the Coscoroba Swan Coscoroba coscoroba, and the endemic South American lungfish Lepidosiren paradoxa are also found. Economically important fish species are the Sorubims Pseudoplatystoma coruscans and P. fasciatum and Manguruyu Paulicea lutkeni. Cattle raising and rice crops are important activities, followed by soybean and sorghum. Hydrological changes have been noticeable since the 1960s, with dam building in the Upper Paraná in Brazil, deforestation, and increase in precipitation. WWF and Fundación Proteger supported the site designation. Ramsar site no. 1366.