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Map of the Amazon rainforest ecoregions as delineated by the WWF. Yellow line encloses the Amazon rainforest. National boundaries shown in black. Satellite image from NASA.
River in the Brazilian Amazon Rainforest.

The Amazon Rainforest (Portuguese: Floresta Amazônica or Amazônia; Spanish: Selva Amazónica or Amazonía) is a moist broadleaf forest in the Amazon Basin of South America. The area, also known as Amazonia or the Amazon Basin encompasses seven million kilometers (1.2 billion acres), though the forest itself occupies some 5.5 million kilometers, located within eight nations: Brazil (with 60 percent of the rainforest), Colombia, Peru, Venezuela, Ecuador, Bolivia, Guyana, Suriname, and French Guiana. States or departments in four nations bear the name Amazonas after it. The Amazon represents over half of the planet's remaining rainforests and comprises the largest and most species-rich tract of tropical rainforest in the world.

Etymology

The name Amazon is said to arise from a battle which Francisco de Orellana had with a tribe of Tapuyas where the women of the tribe fought alongside the men, as was the custom among the entire tribe. Orellana derived the name Amazonas from the ancient Amazons of Asia and Africa described by Herodotus and Diodorus in Greek legends.

Biodiversity

The Amazon River flowing through the rainforest
Deforestation in the Amazon Rainforest threatens many species of tree frogs, which are very sensitive to environmental changes (pictured: Red-eyed Tree Frog)

Wet tropical forests are the most species-rich biome, and tropical forests in the Americas are consistently more species rich than the wet forests in Africa and Asia.[1] As the largest tract of tropical rainforest in the Americas, the Amazonian rainforests have unparalleled biodiversity.

The region is home to about 2.5 million insect species, tens of thousands of plants, and some 2000 birds and mammals. To date, at least 40,000 plant species, 3,000 fish, 1,294 birds, 427 mammals, 427 amphibians, and 378 reptiles have been scientifically classified in the region [2]. Scientists have described between 96,660 and 128,843 invertebrate species in Brazil alone.[3]

The diversity of plant species is the highest on earth with some experts estimating that one square kilometer may contain over 75,000 types of trees and 150,000 species of higher plants.[citation needed] One square kilometer of Amazon rainforest can contain about 90,790 tons of living plants. This constitutes the largest collection of living plants and animal species in the world. One in five of all the birds in the world live in the rainforests of the Amazon.[citation needed] To date, an estimated 438,000 species of plants of economic and social interest have been registered in the region with many more remaining to be discovered or catalogued.[citation needed]

Deforestation

Deforestation is the conversion of forested areas to non-forested areas. The main sources of deforestation in the Amazon are human settlement and development of the land.[4] Between 1991 and 2000, the total area of forest lost in the Amazon rose from 415,000 to 587,000 km² - an area twice the size of Portugal, with most of the lost forest becoming pasture for cattle.[5]

History of Deforestation in the Amazon

Prior to the early 1960’s, access to the Amazon was incredibly restricted and aside from partial clearing along rivers the forest remained basically intact.[6] The key point in deforestation of the Amazon was when the colonists established farms within the forest during the 1600s. Their farming system was based on crop cultivation and the slash and burn method. The colonists were unable to successfully manage their fields and the crops due to the loss of soil fertility and weed invasion[7]. The soils in the Amazon are productive for just a short period of time, and the farmers are therefore constantly moving and clearing more and more land[8]. Amazonian colonization was ruled by cattle raising because ranching required little labor, generated decent profits, and awarded social status in the community. However the results of the farming lead to extensive deforestation and caused extensive environmental damage[9]. An estimated 30% of the deforestation is due to small farmers and the intensity within the area that they inhabit is greater than the area occupied by the medium and large ranchers who possess 89% of the Legal Amazon’s private land. This emphasizes the importance of using previously cleared land for agricultural use, rather the typical easiest political path of distributing still-forested areas[10]. In the Brazilian Amazon, the amount of small farmers versus large landholders changes frequently with economic and demographic pressures.[11]

Causes of Deforestation in the Amazon

The annual rate of deforestation in the Amazon region has continued to increase from 1990 to 2003 because of factors at local, national, and international levels.[12] Brazil is currently the second-largest global producer of soybeans after the United States, and as prices for soybeans rise, the soy farmers are pushing northwards into forested areas of the Amazon. As stated in Brazilian legislation, clearing land for crops or fields is considered an ‘effective use’ of land and is the beginning towards land ownership.[13] Cleared property is also valued 5-10 times more than forested land and for that reason valuable to the owner whose ultimate objective is resale. As stated by Michael Williams,“The people of Brazil have always thought of the Amazon as a communal possession which they felt free to hack, burn, and abandon at will.”[14] The soy industry is the principal source of foreign currency for Brazil; therefore, the needs of soy farmers have been used to validate many of the controversial transportation projects that are developing in the Amazon currently.[15] The first two highways: the Belém-Brasília (1958) and the Cuiaba-Porto Velho (1968) were the only federal highways in the Legal Amazon to be paved and passable year-round before the late 1990’s. These two highways are said to be “at the heart of the ‘arc of deforestation’,” which at present is the focal point area of deforestation in the Brazilian Amazon. The Belém-Brasilia highway attracted nearly two million settlers in the first twenty years. The success of the Belém-Brasilia highway in opening up the forest was re-enacted as paved roads continued to be developed unleashing the irrepressible spread of settlement. The completions of the roads were followed by a wave of resettlement and the settlers had a significant effect on the forest.[16]

Measured Rates of Deforestation in the Amazon

In 1996, the Amazon was reported to have shown a 34% increase in deforestation since 1992[17]. The mean annual deforestation rate from 2000 to 2005 (22,392 km² per year) was 18% higher than in the previous five years (19,018 km² per year) [18]. In Brazil, the Instituto Nacional de Pesquisas Espaciais (INPE, or National Institute of Space Research) produces deforestation figures annually. Their deforestation estimates are derived from 100 to 220 images taken during the dry season in the Amazon by the Landsat satellite, and only consider the loss of the Amazon rainforest biome – not the loss of natural fields or savannah within the rainforest. According to INPE, the original Amazon rainforest biome in Brazil of 4,100,000 km² was reduced to 3,403,000 km² by 2005 – representing a loss of 17.1% [19].

Period Estimated Remaining Forest Cover
in the Brazilian Amazon (sq. km)		 Annual forest
loss (sq. km)		 Percent of 1970
cover remaining		 Total forest loss
since 1970 (sq. km)
1970 3,684,675
1970-1979 3,473,375 21,130 94.3% 211,300
1980-1989 3,262,075 21,130 88.5% 422,600
1990 3,248,265 13,810 88.2% 436,410
1991 3,237,135 11,130 87.9% 447,540
1992 3,223,349 13,786 87.5% 461,326
1993 3,207,939 15,410 87.1% 476,736
1994 3,193,043 14,896 86.7% 491,632
1995 3,163,984 29,059 85.9% 520,691
1996 3,145,824 18,160 85.4% 538,851
1997 3,132,784 13,040 85.0% 551,891
1998 3,115,944 16,840 84.6% 568,731
1999 3,098,685 17,259 84.1% 585,990
2000 3,078,849 19,836 83.6% 605,826
2001 3,060,719 18,130 83.1% 623,956
2002 3,035,219 25,500 82.4% 649,456
2003 3,011,089 24,130 81.7% 673,586
2004 2,984,960 26,129 81.0% 699,715
2005 2,966,060 18,900 80.5% 718,615
[citation needed]


Future of Deforestation

At the current rate, in two decades the Amazon Rainforest will be deplenished by 40% (National Geographic, January 2007) The 2005-2006 year had a 41% drop in deforestation, This is the lowest figure since 1991. Deforestation rates are expected to go down as conservation has been at a very high rate in the past five years. At this rate, it is possible that the Amazon Rainforest will no longer exist by the end of the century.

Carbon dynamics

Aerial roots of red mangrove on an Amazonian river

Not only are environmentalists concerned about the loss of biodiversity which will result from destruction of the forest, they are also concerned about the release of the carbon contained within the vegetation, which could accelerate global warming[citation needed].

File:Amazon Plants.jpg
The many plants and scenery of the Amazon Rainforest

Amazonian evergreen forests account for about 10% of the world's terrestrial primary productivity and 10% of the carbon stores in ecosystems [20] — of the order of 1.1 x 1011 metric tonnes of carbon [21]. Amazonian forests are estimated to have accumulated 0.62 ± 0.37 tonnes of carbon per hectare per year between 1975 and 1996 [21]. Fires related to Amazonian deforestation have made Brazil one of the top greenhouse gas producers. Brazil produces about 300 million metric tonnes of carbon dioxide a year; 200 million of these come from logging and burning in the Amazon.

Conservation

Some environmentalists commonly state the fact that there is not only a biological incentive to protecting the rainforest, but also an economic one. One hectare in the Peruvian Amazon has been calculated to have a value of $6820 if intact forest is sustainably harvested for fruits, latex, and timber; $1000 if clear-cut for commercial timber (not sustainably harvested); or $148 if used as cattle pasture.[22] However, the assumptions of this study have been widely challenged.

The Força Aérea Brasileira has been using Embraer R-99 surveillance aircraft, as part of the SIVAM program, to monitor the forest. At a conference in July 2004, scientists warned that the rainforest will no longer be able to absorb the millions of tons of greenhouse gases annually, as it usually does, because of the increased pace of rainforest destruction. 9,169 square miles of rain forest were cut down in 2003 alone.

In Brazil alone, more than 90 indigenous groups have been destroyed by colonists since the 1900s, and with them have gone centuries of accumulated knowledge of the medicinal value of rainforest species. As indigenous territories continue to be destroyed by deforestation, and ecocide, such as in the Peruvian Amazon[23] indigenous peoples' rainforest communities continue to disappear, while others, like the Urarina continue to struggle to fight for their cultural survival and the fate of their forested territories. Meanwhile, the relationship between nonhuman primates in the subsistence and symbolism of indigenous lowland South American peoples has gained increased attention, as has ethno-biology and community-based conservation efforts.

Within the past four years, the conserved land in the Amazon Rainforest has almost tripled and deforestation rates have dropped up to 60%. About 100 million hectares, or 250 million acres have been put onto some sort of conservation, which adds up to a current amount of 173 million hectares or 432.5 million acres. [24]

Response to climate change

River in the Amazon rainforest.

There is evidence that there have been significant changes in Amazon rainforest vegetation over the last 21,000 years through the last glaciation (LGM) and subsequent deglaciation. Analyses of sediment deposits from Amazon basin paleolakes and from the Amazon Fan indicate that rainfall in the basin during the LGM was lower than for the present, and this was almost certainly associated with reduced moist tropical vegetation cover in the basin[25]. There is debate, however, over how extensive this reduction was. Some scientists argue that the rainforest was reduced to small, isolated refugia separated by open forest and grassland[26]; other scientists argue that the rainforest remained largely intact but extending less far to the North, South and East than is seen today [27]. This debate has proved difficult to resolve because the practical limitations of working in the rainforest mean that data sampling is biased away from the centre of the Amazon basin, and both explanations are reasonably well supported by the available data.

One computer model of future climate change due to greenhouse gas emissions shows that the Amazon rainforest could become unsustainable under conditions of severely reduced rainfall and increased temperatures, leading to an almost complete loss of rainforest cover in the basin by 2100.[28][29] However, simulations of Amazon basin climate change across many different models are not consistent in their estimation of any rainfall response, ranging from weak increases to strong decreases [30]. The result indicates that the rainforest could be threatened though the 21st century by climate change in addition to deforestation.

Impact of Amazon drought

In 2005, parts of the Amazon basin experienced the worst drought in 100 years[31], and there are indications that 2006 could be a second successive year of drought[32]. A 23 July 2006 article in the UK newspaper The Independent reported Woods Hole Research Center results showing that the forest in its present form could survive only three years of drought.[33][34] Scientists at the Brazilian National Institute of Amazonian Research argue in the article that this drought response, coupled with the effects of deforestation on regional climate, are pushing the rainforest towards a "tipping point" where it would irreversibly start to die. It concludes that the forest is on the brink of being turned into savanna or desert, with catastrophic consequences for the world's climate. According to the WWF, the combination of climate change and deforestation increases the drying effect of dead trees that fuels forests fires.[35]

See also

References and footnotes

Urarina shaman, 1988
  1. ^ Turner, I.M. 2001. The ecology of trees in the tropical rain forest. Cambridge University Press, Cambridge. ISBN 0-521-80183-4
  2. ^ Da Silva et al. 2005. The Fate of the Amazonian Areas of Endemism. Conservation Biology 19 (3), 689-694
  3. ^ Lewinsohn T. M.and Prado P.I. 2005. How Many Species Are There in Brazil? Conservation Biology. Volume 19 (3), 619
  4. ^ Bierregaard Jr, R. O., Gascon, C., Lovejoy, T. E., & Mesquita, R. C. (2001). Lessons From Amazonia: the Ecology and Conservation of a Fragmented Forest. Ann Arbor, Michigan: Yale University.
  5. ^ Centre for International Forestry Research (CIFOR) (2004)
  6. ^ Kirby, K. R., Laurance, W. F., Albernaz, A. K., Schroth, G., Fearnside, P. M., Bergen, S., Venticinque, E. M., & De Costa, C. (2006). The future of deforestation in the Brazilian Amazon. Futures of Bioregions, 38, 432-453. Retrieved November 26, 2006, from Science Direct database.
  7. ^ Watkins and Griffiths, J. (2000). Forest Destruction and Sustainable Agriculture in the Brazilian Amazon: a Literature Review (Doctoral dissertation, The University of Reading, 2000). Dissertation Abstracts International, 15-17
  8. ^ Watkins and Griffiths, J. (2000). Forest Destruction and Sustainable Agriculture in the Brazilian Amazon: a Literature Review (Doctoral dissertation, The University of Reading, 2000). Dissertation Abstracts International, 15-17.
  9. ^ Williams, M. (2006). Deforesting the Earth: From Prehistory to Global Crisis. Chicago, IL: The University of Chicago Press.
  10. ^ Fernside, P. M. (2005). Deforestation in Brazilian Amazonia: History, Rates, and Consequences. Conservation Biology, 19, 680-688.
  11. ^ Fernside, P. M. (2005). Deforestation in Brazilian Amazonia: History, Rates, and Consequences. Conservation Biology, 19, 680-688.
  12. ^ Kirby, K. R., Laurance, W. F., Albernaz, A. K., Schroth, G., Fearnside, P. M., Bergen, S., Venticinque, E. M., & De Costa, C. (2006). The future of deforestation in the Brazilian Amazon. Futures of Bioregions, 38, 432-453. Retrieved November 26, 2006, from Science Direct database.
  13. ^ Kirby, K. R., Laurance, W. F., Albernaz, A. K., Schroth, G., Fearnside, P. M., Bergen, S., Venticinque, E. M., & De Costa, C. (2006). The future of deforestation in the Brazilian Amazon. Futures of Bioregions, 38, 432-453. Retrieved November 26, 2006, from Science Direct database.
  14. ^ Williams, M. (2006). Deforesting the Earth: From Prehistory to Global Crisis. Chicago, IL: The University of Chicago Press.
  15. ^ Kirby, K. R., Laurance, W. F., Albernaz, A. K., Schroth, G., Fearnside, P. M., Bergen, S., Venticinque, E. M., & De Costa, C. (2006). The future of deforestation in the Brazilian Amazon. Futures of Bioregions, 38, 432-453. Retrieved November 26, 2006, from Science Direct database.
  16. ^ Williams, M. (2006). Deforesting the Earth: From Prehistory to Global Crisis. Chicago, IL: The University of Chicago Press.
  17. ^ Beef exports fuel loss of Amazonian Forest. CIFOR News Online, Number 36
  18. ^ Barreto, P.; Souza Jr. C.; Noguerón, R.; Anderson, A. & Salomão, R. 2006. Human Pressure on the Brazilian Amazon Forests. Imazon. Retrieved September 28, 2006. (The Imazon web site contains many resources relating to the Brazilian Amazonia.)
  19. ^ . National Institute for Space Research (INPE) (2005). The INPE deforestation figures for Brazil were cited on the WWF Websitein April 2006.
  20. ^ Melillo, J.M., A.D. McGuire, D.W. Kicklighter, B. Moore III, C.J. Vörösmarty and A.L. Schloss. 1993. Global climate change and terrestrial net primary production. Nature 363:234–240.
  21. ^ a b Tian, H., J.M. Melillo, D.W. Kicklighter, A.D. McGuire, J. Helfrich III, B. Moore III and C.J. Vörösmarty. 2000. Climatic and biotic controls on annual carbon storage in Amazonian ecosystems. Global Ecology and Biogeography 9:315–335.
  22. ^ Peters, C.M., Gentry, A.H. & Mendelsohn, R.O. (1989) Valuation of an Amazonian forest. Nature 339: 655-656.
  23. ^ Dean, Bartholomew. (2003) State Power and Indigenous Peoples in Peruvian Amazonia: A Lost Decade, 1990-2000. In The Politics of Ethnicity Indigenous Peoples in Latin American States David Maybury-Lewis, Ed. Harvard University Press
  24. ^ Cormier, L. 2006. A Preliminary Review of Neotropical Primates in the Subsistence and Symbolism of Indigenous Lowland South American Peoples. Ecological and Environmental Anthropology, University of Georgia, April 16, 2006. Retrieved September 28, 2006.
  25. ^ Colinvaux, P.A., De Oliveira, P.E. 2000. Palaeoecology and climate of the Amazon basin during the last glacial cycle. Wiley InterScience. (abstract)
  26. ^ Van der Hammen, T., Hooghiemstra, H.. 2002. Neogene and Quaternary history of vegetation, climate, and plant diversity in Amazonia. Elsevier Science Ltd. (abstract)
  27. ^ Colinvaux, P.A., De Oliveira, P.E., Bush, M.B. 2002. Amazonian and neotropical plant communities on glacial time-scales: The failure of the aridity and refuge hypotheses. Elsevier Science, Ltd. (abstract)
  28. ^ Cox, Betts, Jones, Spall and Totterdell. 2000. Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model. Nature, November 9, 2000. (subscription required)
  29. ^ Radford, T. 2002. World may be warming up even faster. The Guardian.
  30. ^ Houghton, J.T. et al. 2001. Climate Change 2001: The Scientific Basis. Intergovernmental Panel on Climate Change.
  31. ^ Environmental News Service - Amazon Drought Worst in 100 Years
  32. ^ Drought Threatens Amazon Basin - Extreme conditions felt for second year running
  33. ^ Amazon rainforest 'could become a desert' , The Independent, July 23, 2006. Retrieved September 28, 2006.
  34. ^ Dying Forest: One year to save the Amazon, The Independent, July 23, 2006. Retrieved September 28, 2006.
  35. ^ Climate change a threat to Amazon rainforest, warns WWF, World Wide Fund for Nature, March 22, 2006. Retrieved September 28, 2006.
  • Sheil, D. and S. Wunder. 2002. The value of tropical forest to local communities: complications, caveats, and cautions. Conservation Ecology 6(2): 9. [1]
  • "Deforestation." World Geography. Columbus, Ohio: McGraw-Hill/Glencoe, 2000. 202-204

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