 The flood plain of the river is part of the Paraná Delta and Islands Ecoregion.The original ecosystem, especially in the Lower Delta, has been heavily modified by deforestation, hunting, fishing and the introduction of foreign species of flora, as well as damaged by domestic and industrial pollution.It hosts species such as the marsh deer, the capybara, the neotropical river otter, the Pampas cat, the jaguar, the coypu and the red-faced guan, some of them endangered.