The Site is a complex of estuaries, rivers, lagoons, permanent freshwater swamps and seasonally flooded grasslands, interspersed with riparian forests and gallery forests. It provides support and shelter for dozens of species. It is the park with the greatest diversity of amphibian species in the region, including notable species such as the waxy monkey tree frog (Phyllomedusa sauvagii) and the dotted tree frog (Boana punctata). Within the federal system of protected areas, the park ranks second in terms of the total diversity of species. It provides habitat to a significant number of vulnerable species including the marsh deer (Blastocerus dichotomus), the lowland tapir (Tapirus terrestris), the white-lipped peccary (Tayassu pecari), the giant armadillo (Priodontes maximus) and the giant anteater (Myrmecophaga tridactyla). The Site is also listed as an Important Bird Area (IBA); it shelters hundreds of bird species during the nesting season, including the turquoise-fronted Amazon (Amazona aestiva), the great white egret (Ardea alba) and the bare-faced curassow (Crax fasciolata). It has suffered the impacts of illegal hunting, change in its vegetation cover because of grassland burning, and the advance of the agricultural frontier for cotton and banana crops.