Cantão

Cantão is a tropical forest ecosystem located in the central Araguaia river basin, the southeastern edge of the Amazon biome, in the Brazilian state of . It is one of the biologically richest areas of the eastern Amazon, with over 700 species of birds, nearly 300 species of fish (more than in all of Europe), and large populations of endangered species such as the giant otter and the black cayman. About 90% of the Cantão ecosystem is protected within Cantão State Park.

Due to its geographical location and topography, the Cantão ecosystem combines several unique features that contribute to its high biodiversity and productivity:

Roughly in the middle of its course, the Araguaia river splits into two forks, with the western one retaining the name Araguaia and the eastern one being called Rio Javaés. They flow their separate ways for over 400 meandering kilometers before reuniting, thus forming the Ilha do Bananal, the world's largest river island. Where the Javaés pours back into the main Araguaia, it forms a broad inland delta where it pours back into the main Araguaia, a 100,000 hectare triangular expanse of igapó flooded forest, blackwater river channels, and oxbow lakes. This inland delta is called Cantão.

During the wet season, from December to May, the waters of the Araguaia and the Javaés rise between six and nine meters over their dry season levels. The Javaés then overflows its banks and fills its broad low floodplain, which becomes an immense mosaic of lakes, marshes, and gallery forest. The water becomes saturated with tannins from the submerged vegetation, and the Javaés becomes a typical blackwater river, its waters turning considerably darker than those of the Araguaia. All this water is funneled through the delta of the Javaés, and during the floods, almost all of the Cantão ecosystem is submerged by fast flowing black water, for in effect the Javaés now becomes a single sheet of water nearly twenty kilometers wide, running through the open channels and under the canopy of the flooded forests of its delta with equal swiftness.

Five distinct natural communities, each with its own unique species assemblages, occur within the Cantão ecosystem:

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