The mouth of Arroyo Zabala, between the districts of Necochea and San Cayetano, is an area of coastal dunes with a great wealth of animal and plant species, which has not yet undergone serious environmental transformations, since it is far from populated centers and is difficult to access. In the Arroyo Zabala Natural Reserve, 105 species of higher plants, 115 species of birds, 10 species of terrestrial mammals, 5 species of reptiles, and 4 species of amphibians have been identified. Several of these species are considered endemic or of localized distribution. It is also an important refuge for species that were once widely distributed, but are now facing serious conservation problems, such as the Ruddy-headed goose, declared a Natural Monument (Law 12,250). It is also an important population corridor for some species that penetrate to the north, such as the yarará ñata and the escuercito chico, or to the south, such as the capybara.