The Amazon Basin is the part of South America drained by the Amazon River and its tributaries that drains an area of about 6,915,000 km2 (2,670,000 sq mi), or roughly 40 percent of South America. The basin is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela.
Most of the basin is covered by the Amazon rainforest, also known as Amazonia. With a 5,500,000 km2 (2,100,000 sq mi) area of dense tropical forest, this is the largest rainforest in the world.
As much of the Amazon is unexplored, many of its indigenous plants and animals are unknown. Plant growth is dense and its variety of animals inhabitants is comparatively high due to the heavy rainfall and the dense and extensive evergreen and coniferous forests. The forest cover is in fact so thick that a dense "roof" is created by the leaves and branches, which does not allow the sunlight to reach the ground. The ground remains dark and damp and only shade tolerant trees and vegetation will grow here. Orchids and bromeliads exploit trees and other plants to get closer to the sunlight. They grow hanging onto the branches or tree trunks with aerial roots, not as parasites but as epiphytes. One tropical fruit tree that is native to the Amazon is the abiu. The Amazon Basin contains thousands of plant species. The bromeliads are special in that they hold water, and frogs may use these plants to hatch their eggs, besides many other living organisms that have their homes in them.
More than 14,000 species of mammal are found in the Amazon, the majority of which are bats and rodents. Mammals include the Jaguar, Ocelot, Capybara and South America's largest mammal the Tapir.
About 1500 bird species inhabit the Amazon Basin. Macaws are famous for gathering by the hundreds, even thousands, along the clay cliffs of the Amazon river where they feed on minerals which help the birds process toxins found in the seeds they eat. The biodiversity of the Amazon and the sheer number of diverse bird species is given by the number of different bird families that reside in these humid forests. An example of such would be the cotinga family, to which the Guianan Cock-of-the-rock belong. Birds such as toucans, and hummingbirds are also found here.
Many reptiles species are illegally collected and exported for the international pet trade. Live animals are the fourth largest commodity in the smuggling industry after drugs, diamonds, and weapons. The worlds largest snake the Anaconda roams the shallow waters of the Amazon whilst the Emerald Tree Boa and Boa Constrictor live in the tree tops. Also the Basilisk Lizard lives in the Amazon Basin and it can walk across water.
More than 1,000 species of amphibians swim and are found in the Amazon. Unlike temperate frogs which are mostly limited to habitats near water, tropical frogs are most abundant in the trees and relatively few are found near bodies of water on the forest floor. The reason for this occurrence is quite simple: frogs must always keep their skin moist since almost half of their respiration in carried out through their skin. The high humidity of the rainforest and frequent rainstorms gives tropical frogs infinitely more freedom to move into the trees and escape the many predators of rainforest waters. The differences between temperate and tropical frogs extend beyond their habitat. Whereas nearly all temperate frogs lay their eggs in water, the majority of rainforest species place eggs in vegetation or lay them in the ground. By leaving the water, frogs avoid egg-predators like fish, shrimp, aquatic insects, and insect larvae. Among the best known of rainforest amphibians are the tiny, but brilliantly colored poison dart (arrow) frogs [members of the Dendrobatidae family]. These striking but slow-moving frogs secrete powerful toxins from glands on their backs and use their color to advertise their toxic composition to potential predators
With more than 2,200 species the Amazon Basin has a larger fish fauna than any other river basin on Earth, and Amazonia is the center of diversity for Neotropical fishes. The remarkable species richness can in part be explained by the large differences between the various parts of the Amazon Basin, resulting in many fish species that are endemic to small regions. For example, fauna in clearwater rivers differ from fauna in blackwater rivers, fauna in slow moving sections show distinct differences compared to that in rapids, fauna in small streams differ from that in major rivers, and fauna in shallow sections show distinct differences compared to that in deep parts.
Some of the major fish groups of the Amazon Basin include:
- Order Gymnotiformes: Neotropical electric fishes
- Family Characidae: tetras and allies
- Family Loricariidae: armoured catfishes
- Subfamily Cichlinae: Neotropical cichlids
- Subfamily Poeciliinae: guppies and relative
Over 90% of the animal species in the Amazon are insects. Whereas all of Europe has some 321 butterfly species, the Manu National Park in Peru (4000 hectare-survey) has 1300 species, while Tambopata National Park (5500 hectare-survey) has at least 1231 species . Around 25% of the world's 2 million described animals species are beetles (Coleoptera). The Titan beetle (Titanus giganteus) can have a body length (not including antennae) of over 6.5 inches (16 cm). A single square mile of rainforest often houses more than 50,000 insect species. Some scientists estimate that 30% of the animal biomass of the Amazon Basin is made up of ants.
Climate and seasons
The Amazon River Basin has low-water season, and a wet season during which the rivers flood adjacent low lying forests. The climate of the basin is generally hot and humid. In some areas, however, the winter months (June–September) can bring cold snaps, fueled by Antarctic winds travelling along the adjacent Andes mountain range. Such cold conditions can be devastating for some of the region's tropical plant and animal species.
Amazonia is very sparsely populated. There are scattered settlements inland, but most of the population lives in a few larger cities on the banks of the Amazon and other major rivers, such as in Iquitos (Peru), Manaus and Belém (Brazil). In many regions, the forest has been cleared for soy bean plantations and ranching (the most extensive non-forest use of the land) and some of the inhabitants harvest wild rubber latex and Brazil nuts. This is a form of extractive farms, where the trees are not cut down, and thus this is a relatively sustainable human impact.
The largest organization fighting for the indigenous peoples in this area is COICA, which is a supraorganization emcompassing all indigenous rights organizations working in the Amazon Basin area, living in several countries.
The river is the principal path of transportation for people and produce in the regions, with transport ranging from balsa rafts and dugout canoes to hand built wooden river craft and modern steel hulled craft.
Sustainable opportunistic agriculture in undeveloped areas
Seasonal floods excavate and redistribute nutrient-rich silt onto beaches and islands, enabling dry-season riverside agriculture of rice, beans, and corn on the river's shoreline without the addition of fertilizer, with additional slash and burn agriculture on higher floodplains. Fishing provides additional food year round, and free-range chickens need little or no food beyond what they can forage locally. Charcoal made largely from forest and shoreline deadfall is produced for use in urban areas. Exploitation of bush meat, particularly deer and turtles is common.
Non-sustainable agriculture in developed areas
Extensive deforestation, particularly in Brazil, is of considerable worldwide concern as it is leading to the extinction of known and unknown species, reducing biological diversity and negatively impacting soil, water, and air quality. A final part of the deforestation process is the large-scale production of charcoal for industrial processes such as steel manufacturing. Soils within the region are generally shallow and cannot be used for more than a few seasons without the addition of imported fertilizers.
The Amazon Basin is bounded by the Guiana Highlands to the north and the Brazilian Highlands to the south. The Amazon, which rises in the Andes Mountains at the west of the basin, is the second longest river in the world. It covers a distance of about 6,400 km before draining into the Atlantic Ocean. The Amazon and its tributaries form the largest volume of water. The Amazon accounts for about 20% of the total water carried to the oceans by rivers. Some of the Amazon Rainforest is deforested because of a growing interest in hardwood products.
The highest point in the watershed of the Amazon is the peak of Yerupajá at 6,635 m (21,768 ft).
The most widely spoken language in the Amazon is Portuguese, followed closely by Spanish. On the Brazilian side Portuguese is spoken by at least 98% of the population, whilst in the Spanish-speaking countries a large number of speakers of indigenous languages are present, though Spanish is predominant.
There are hundreds of native languages still spoken in the Amazon, most of which are spoken by only a handful of people, and thus are critically endangered. One of the most widely spoken languages in the Amazon is Nheengatu, which is descended from the ancient Tupi language, originally spoken in the coastal and central regions of Brazil. It was brought to its present location along the Rio Negro by Brazilian colonizers who, until the mid-17th century, who primarily used Tupi rather than the official Portuguese to communicate. Besides modern Nheengatu, other languages of the Tupi family are spoken there, along with other language families like Jê (with its important sub-branch Jayapura spoken in the Xingu River region and elsewhere), Arawak, Karib, Arawá, Yanomamo, Matsés and others.
- Roach, John (18 June 2007). "Amazon Longer Than Nile River, Scientists Say". National Geographic.
- Goulding, M., Barthem, R. B. and Duenas, R. (2003). The Smithsonian Atlas of the Amazon, Smithsonian Books ISBN 1588341356
- Butler, Rhett A. (9 January 2006) “Diversities of Image – Rainforest Biodiversity.” Mongabay.com.
- James S. Albert; Roberto E. Reis (8 March 2011). Historical Biogeography of Neotropical Freshwater Fishes. p. 308. ISBN 9780520268685. Retrieved 28 June 2011.
- Stewart, D. J., M. Ibarra, and R.. Barriga-Salazar (2002). Comparison of Deep-River and Adjacent Sandy-Beach Fish Assemblages in the Napo River Basin, Eastern Ecuador. Copeia 2002(2): 333-343
- Mendonça, F. P., W. E. Magnusson, J. Zuanon and C. M. Taylor. (2005) Relationships between habitat characteristics and fish assemblages in small streams of Central Amazonia. Copeia 2005(4): 751-764
- Petherick, Anna (2010). "Cold empties Bolivian rivers of fish". Nature. doi:10.1038/news.2010.437.
- Dematteis, Lou; Szymczak, Kayana (June 2008). Crude Reflections/Cruda Realidad: Oil, Ruin and Resistance in the Amazon Rainforest. City Lights Publishers. ISBN 978-0-87286-472-6.
- Herndon and Gibbon Lieutenants United States Navy The First North American Explorers of the Amazon Valley, by Historian Normand E. Klare. Actual Reports from the explorers are compared with present Amazon Basin conditions.
- Scientists find Evidence Discrediting Theory Amazon was Virtually Unlivable by The Washington Post
- "The Course of the River of the Amazons, Based on the Account of Christopher d’Acugna" from 1680