The Oasis is an artificial basin along the Sele River consisting of inundated meadows, riparian woodland, flooded forest, fens and swamps. The reservoir was created by the damming of the Sele in the first half of the 20th century. The dominant vegetation comprises floating and emergent vegetation typical of the Mediterranean Region. The Site hosts one of the largest populations in Italy of the the European otter (Lutra lutra) and is important as a resting and nesting site for waterfowl including the threatened common pochard (Aythya ferina). It features a rich diversity of amphibians including the endangered Appenine yellow-bellied toad (Bombina pachypus). Small-scale agriculture is practiced by local residents, and there is a visitor’s centre with nature trails and facilities for school visits. The Site is impacted by dam operation and invasive species.