Key Habitats
Tropical Rainforest
With an area of between 5.5 and 6.2 million square kilometers, the Amazon is the largest rainforest in the world. It comprises a great variety of unique moist, broadleaf forests, including a portion of its southwest dominated by bamboo.
Riverine Systems
The Amazon river basin is the largest watershed in the world. It drains over 35 percent of the South American continent via 1,100 tributaries and a main river that extends for over 6,400 km (4,000 mi). A diversity of riverine biomes provide habitat for about 2,500 species of fish (not including an estimated 1,000 species not yet catalogued) and a unique array of mammalian species including the giant otter and the Amazon river dolphin.
Floodplain Forests
About 3-4% of the Amazon rainforest is routinely inundated by river floods up to 50 feet (12 to 15 metres) above low river, making a unique section of the forest which has much richer soils than the surrounding forest. Because these floodplain forests receive rich sediment from the Andes Mountains, they host an overall higher number of species along with unique niche ecosystems.
Savanna
Located alongside and to the south of the rainforest, the Brazilian “cerrado” or tropical savanna is itself an enormous ecosystem with over 4,800 endemic species. While greater attention has gone to the loss of rainforest, the Cerrado is also threatened by unsustainable agriculture and cattle ranching. Its fate is tied to that of the rainforest, as halting development the forest has often come at the expense of agribusiness degrading the Cerrado.
Most Pressing Issues
River Damming
Over 100 hydropower dams have been built in the Amazon basin to date, most notably the recent Belo Monte Dam—the world’s fourth-largest hydroelectric project—which now blocks the 1,000-mile Xingu River, a major tributary of the Amazon. Existing and proposed dams have the potential to trigger enormous hydrophysical and biotic disturbances in the region affecting the Amazon basin’s floodplains, estuary and sediment plume.
Deforestation
Over the last 50 years, the seemingly infinite Amazon forest has lost at least 17% of its forest cover. Deforestation on a large scale began in the 20th century, driven by industry, plantation agriculture, and ranching. Although conservation measures have since protected parts of the forest, deforestation (driven today by cattle ranching more than any other factor) fells thousands of acres per year.
Savannization
While the Cerrado itself suffers from destruction by agribusiness and other extractive economic activities, 40% of the Amazon rainforest is at risk of permanent transition into savannah.
Water Pollution
Water pollution is worsening in the Amazon as a result of extensive logging in the rainforest and the introduction of massive livestock operations. Mercury pollution from mining is also threatening wildlife including fish that are critical to the food security of indigenous, rural and urban communities.
