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Tropical rainforests are rainforests that occur in areas of tropical rainforest climate in which there is no dry season – all months have an average precipitation of at least 60 mm – and may also be referred to as lowland equatorial evergreen rainforest. True rainforests are typically found between 10 degrees north and south of the equator (see map); they are a sub-set of the tropical forest biome that occurs roughly within the 28-degree latitudes (in the equatorial zone between the Tropic of Cancer and Tropic of Capricorn). Within the World Wildlife Fund's biome classification, tropical rainforests are a type of tropical moist broadleaf forest (or tropical wet forest) that also includes the more extensive seasonal tropical forests.

An area of the Amazon rainforest in Brazil. The tropical rainforests of South America contain the largest diversity of species on Earth.
Location of tropical (dark green) and temperate/subtropical (light green) rainforests in the world.
Tropical rainforest climate zones (Af).

Contents

Amazon River rain forest in Peru

Tropical rainforests are characterized by two words: hot and wet. Mean monthly temperatures exceed 18 °C (64 °F) during all months of the year. Average annual rainfall is no less than 1,680 mm (66 in) and can exceed 10 m (390 in) although it typically lies between 1,750 mm (69 in) and 3,000 mm (120 in). This high level of precipitation often results in poor soils due to leaching of soluble nutrients in the ground.

Tropical rainforests exhibit high levels of biodiversity. Around 40% to 75% of all biotic species are indigenous to the rainforests. Rainforests are home to half of all the living animal and plant species on the planet. Two-thirds of all flowering plants can be found in rainforests. A single hectare of rainforest may contain 42,000 different species of insect, up to 807 trees of 313 species and 1,500 species of higher plants. Tropical rainforests have been called the "world's largest pharmacy", because over one quarter of natural medicines have been discovered within them. It is likely that there may be many millions of species of plants, insects and microorganisms still undiscovered in tropical rainforests.

Tropical rainforests are among the most threatened ecosystems globally due to large-scale fragmentation as a result of human activity. Habitat fragmentation caused by geological processes such as volcanism and climate change occurred in the past, and have been identified as important drivers of speciation. However, fast human driven habitat destruction is suspected to be one of the major causes of species extinction. Tropical rain forests have been subjected to heavy logging and agricultural clearance throughout the 20th century, and the area covered by rainforests around the world is rapidly shrinking.

History

Tropical rainforests have existed on earth for hundreds of millions of years. Most tropical rainforests today are on fragments of the Mesozoic era supercontinent of Gondwana. The separation of the landmass resulted in a great loss of amphibian diversity while at the same time the drier climate spurred the diversification of reptiles. The division left tropical rainforests located in five major regions of the world: tropical America, Africa, Southeast Asia, Madagascar, and New Guinea, with smaller outliers in Australia. However, the specifics of the origin of rainforests remain uncertain due to an incomplete fossil record.

Other types of tropical forest

Main article: Tropical forest

Several biomes may appear similar-to, or merge via ecotones with, tropical rainforest:

Moist seasonal tropical forest
Daintree "rainforest" in Queensland is actually a seasonal tropical forest.

Moist seasonal tropical forests receive high overall rainfall with a warm summer wet season and a cooler winter dry season. Some trees in these forests drop some or all of their leaves during the winter dry season, thus they are sometimes called "tropical mixed forest". They are found in parts of South America, in Central America and around the Caribbean, in coastal West Africa, parts of the Indian subcontinent, and across much of Indochina.

Montane rainforests

These are found in cooler-climate mountainous areas, becoming known as cloud forests at higher elevations. Depending on latitude, the lower limit of montane rainforests on large mountains is generally between 1500 and 2500 m while the upper limit is usually from 2400 to 3300 m.

Flooded rainforests

Tropical freshwater swamp forests, or "flooded forests", are found in Amazon basin (the Várzea) and elsewhere.

Rainforests are divided into different strata, or layers, with vegetation organized into a vertical pattern from the top of the soil to the canopy. Each layer is a unique biotic community containing different plants and animals adapted for life in that particular strata. Only the emergent layer is unique to tropical rainforests, while the others are also found in temperate rainforests.

Forest floor

Western lowland gorilla

The forest floor, the bottom-most layer, receives only 2% of the sunlight. Only plants adapted to low light can grow in this region. Away from riverbanks, swamps and clearings, where dense undergrowth is found, the forest floor is relatively clear of vegetation because of the low sunlight penetration. This more open quality permits the easy movement of larger animals such as: ungulates like the okapi (Okapia johnstoni), tapir (Tapirus sp.), Sumatran rhinoceros (Dicerorhinus sumatrensis), and apes like the western lowland gorilla (Gorilla gorilla), as well as many species of reptiles, amphibians, and insects. The forest floor also contains decaying plant and animal matter, which disappears quickly, because the warm, humid conditions promote rapid decay. Many forms of fungi growing here help decay the animal and plant waste.

Understory layer

Main article: Understory

The understory layer lies between the canopy and the forest floor. The understory is home to a number of birds, small mammals, insects, reptiles, and predators. Examples include leopard (Panthera pardus), poison dart frogs (Dendrobates sp.), ring-tailed coati (Nasua nasua), boa constrictor (Boa constrictor), and many species of Coleoptera. The vegetation at this layer generally consists of shade-tolerant shrubs, herbs, small trees, and large woody vines which climb into the trees to capture sunlight. Only about 5% of sunlight breaches the canopy to arrive at the understory causing true understory plants to seldom grow to 3 m (10 feet). As an adaptation to these low light levels, understory plants have often evolved much larger leaves. Many seedlings that will grow to the canopy level are in the understory.

Canopy layer

Main article: Canopy (ecology)

The canopy is the primary layer of the forest, forming a roof over the two remaining layers. It contains the majority of the largest trees, typically 30–45 m in height. Tall, broad-leaved evergreen trees are the dominant plants. The densest areas of biodiversity are found in the forest canopy, as it often supports a rich flora of epiphytes, including orchids, bromeliads, mosses and lichens. These epiphytic plants attach to trunks and branches and obtain water and minerals from rain and debris that collects on the supporting plants. The fauna is similar to that found in the emergent layer, but more diverse. It is suggested that the total arthropod species richness of the tropical canopy might be as high as 20 million. Other species habituating this layer include many avian species such as the yellow-casqued wattled hornbill (Ceratogymna elata), collared sunbird (Anthreptes collaris), grey parrot (Psitacus erithacus), keel-billed toucan (Ramphastos sulfuratus), scarlet macaw (Ara macao) as well as other animals like the spider monkey (Ateles sp.), African giant swallowtail (Papilio antimachus), three-toed sloth (Bradypus tridactylus), kinkajou (Potos flavus), and tamandua (Tamandua tetradactyla).

Emergent layer

The emergent layer contains a small number of very large trees, called emergents, which grow above the general canopy, reaching heights of 45–55 m, although on occasion a few species will grow to 70–80 m tall. Some examples of emergents include: Balizia elegans, Dipteryx panamensis, Hieronyma alchorneoides, Hymenolobium mesoamericanum, Lecythis ampla and Terminalia oblonga. These trees need to be able to withstand the hot temperatures and strong winds that occur above the canopy in some areas. Several unique faunal species inhabit this layer such as the crowned eagle (Stephanoaetus coronatus), the king colobus (Colobus polykomos), and the large flying fox (Pteropus vampyrus).

However, stratification is not always clear. Rainforests are dynamic and many changes affect the structure of the forest. Emergent or canopy trees collapse, for example, causing gaps to form. Openings in the forest canopy are widely recognized as important for the establishment and growth of rainforest trees. It is estimated that perhaps 75% of the tree species at La Selva Biological Station, Costa Rica are dependent on canopy opening for seed germination or for growth beyond sapling size, for example.

Climates

Artificial tropical rainforest in Barcelona

Tropical rainforests are located around and near the equator, therefore having what is called an equatorial climate characterized by three major climatic parameters: temperature, rainfall, and dry season intensity. Other parameters that affect tropical rainforests are carbon dioxide concentrations, solar radiation, and nitrogen availability. In general, climatic patterns consist of warm temperatures and high annual rainfall. However, the abundance of rainfall changes throughout the year creating distinct moist and dry seasons. Tropical forests are classified by the amount of rainfall received each year, which has allowed ecologists to define differences in these forests that look so similar in structure. According to Holdridge's classification of tropical ecosystems, true tropical rainforests have an annual rainfall greater than 2 m and annual temperature greater than 24 degrees Celsius, with a potential evapotranspiration ratio (PET) value of <0.25. However, most lowland tropical forests can be classified as tropical moist or wet forests, which differ in regards to rainfall. Tropical forest ecology- dynamics, composition, and function- are sensitive to changes in climate especially changes in rainfall.

Soils

Soil types

Soil types are highly variable in the tropics and are the result of a combination of several variables such as climate, vegetation, topographic position, parent material, and soil age. Most tropical soils are characterized by significant leaching and poor nutrients, however there are some areas that contain fertile soils. Soils throughout the tropical rainforests fall into two classifications which include the ultisols and oxisols. Ultisols are known as well weathered, acidic red clay soils, deficient in major nutrients such as calcium and potassium. Similarly, oxisols are acidic, old, typically reddish, highly weathered and leached, however are well drained compared to ultisols. The clay content of ultisols is high, making it difficult for water to penetrate and flow through. The reddish color of both soils is the result of heavy heat and moisture forming oxides of iron and aluminium, which are insoluble in water and not taken up readily by plants.

Soil chemical and physical characteristics are strongly related to above ground productivity and forest structure and dynamics. The physical properties of soil control the tree turnover rates whereas chemical properties such as available nitrogen and phosphorus control forest growth rates. The soils of the eastern and central Amazon as well as the Southeast Asian Rainforest are old and mineral poor whereas the soils of the western Amazon (Ecuador and Peru) and volcanic areas of Costa Rica are young and mineral rich. Primary productivity or wood production is highest in western Amazon and lowest in eastern Amazon which contains heavily weathered soils classified as oxisols. Additionally, Amazonian soils are greatly weathered, making them devoid of minerals like phosphorus, potassium, calcium, and magnesium, which come from rock sources. However, not all tropical rainforests occur on nutrient poor soils, but on nutrient rich floodplains and volcanic soils located in the Andean foothills, and volcanic areas of Southeast Asia, Africa, and Central America.

Oxisols, infertile, deeply weathered and severely leached, have developed on the ancient Gondwanan shields. Rapid bacterial decay prevents the accumulation of humus. The concentration of iron and aluminium oxides by the laterization process gives the oxisols a bright red color and sometimes produces minable deposits (e.g., bauxite). On younger substrates, especially of volcanic origin, tropical soils may be quite fertile.

Nutrient recycling

This high rate of decomposition is the result of phosphorus levels in the soils, precipitation, high temperatures and the extensive microorganism communities. In addition to the bacteria and other microorganisms, there are an abundance of other decomposers such as fungi and termites that aid in the process as well. Nutrient recycling is important because below ground resource availability controls the above ground biomass and community structure of tropical rainforests. These soils are typically phosphorus limited, which inhibits net primary productivity or the uptake of carbon. The soil contains microbial organisms such as bacteria, which break down leaf litter and other organic matter into inorganic forms of carbon usable by plants through a process called decomposition. During the decomposition process the microbial community is respiring, taking up oxygen and releasing carbon dioxide. The decomposition rate can be evaluated by measuring the uptake of oxygen. High temperatures and precipitation increase decomposition rate, which allows plant litter to rapidly decay in tropical regions, releasing nutrients that are immediately taken up by plants through surface or ground waters. The seasonal patterns in respiration are controlled by leaf litter fall and precipitation, the driving force moving the decomposable carbon from the litter to the soil. Respiration rates are highest early in the wet season because the recent dry season results in a large percentage of leaf litter and thus a higher percentage of organic matter being leached into the soil.

Buttress roots

A common feature of many tropical rainforests is the distinct buttress roots of trees. Instead of penetrating to deeper soil layers, buttress roots create a widespread root network at the surface for more efficient uptake of nutrients in a very nutrient poor and competitive environment. Most of the nutrients within the soil of a tropical rainforest occur near the surface because of the rapid turnover time and decomposition of organisms and leaves. Because of this, the buttress roots occur at the surface so the trees can maximize uptake and actively compete with the rapid uptake of other trees. These roots also aid in water uptake and storage, increase surface area for gas exchange, and collect leaf litter for added nutrition. Additionally, these roots reduce soil erosion and maximize nutrient acquisition during heavy rains by diverting nutrient rich water flowing down the trunk into several smaller flows while also acting as a barrier to ground flow. Also, the large surface areas these roots create provide support and stability to rainforests trees, which commonly grow to significant heights. This added stability allows these trees to withstand the impacts of severe storms, thus reducing the occurrence of fallen trees.

Forest succession

Succession is an ecological process that changes the biotic community structure over time towards a more stable, diverse community structure after an initial disturbance to the community. The initial disturbance is often a natural phenomenon or human caused event. Natural disturbances include hurricanes, volcanic eruptions, river movements or an event as small as a fallen tree that creates gaps in the forest. In tropical rainforests, these same natural disturbances have been well documented in the fossil record, and are credited with encouraging speciation and endemism. Human land use practices have led to large-scale deforestation. In many tropical countries such as Costa Rica these deforested lands have been abandoned and forests have been allowed to regenerate through ecological succession. These regenerating young successional forests are called secondary forests or second-growth forests.

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Young orangutan at Bukit Lawang, Sumatra

Tropical rainforests exhibit a vast diversity in plant and animal species. The root for this remarkable speciation has been a query of scientists and ecologists for years. A number of theories have been developed for why and how the tropics can be so diverse.

Interspecific competition

Interspecific competition results from a high density of species with similar niches in the tropics and limited resources available. Species which "lose" the competition may either become extinct or find a new niche. Direct competition will often lead to one species dominating another by some advantage, ultimately driving it to extinction. Niche partitioning is the other option for a species. This is the separation and rationing of necessary resources by utilizing different habitats, food sources, cover or general behavioral differences. A species with similar food items but different feeding times is an example of niche partitioning.

Pliestocene refugia

The theory of Pleistocene refugia was developed by Jürgen Haffer in 1969 with his article Speciation of Amazonian Forest Birds. Haffer proposed the explanation for speciation was the product of rainforest patches being separated by stretches of non-forest vegetation during the last glacial period. He called these patches of rainforest areas refuges and within these patches allopatric speciation occurred. With the end of the glacial period and increase in atmospheric humidity, rainforest began to expand and the refuges reconnected. This theory has been the subject of debate. Scientists are still skeptical of whether or not this theory is legitimate. Genetic evidence suggests speciation had occurred in certain taxa 1–2 million years ago, preceding the Pleistocene.

Habitation

Tropical rainforests have harboured human life for many millennia, with many Indian tribes in South- and Central America, who belong to the Indigenous peoples of the Americas, the Congo Pygmies in Central Africa, and several tribes in South-East Asia, like the Dayak people and the Penan people in Borneo. Food resources within the forest are extremely dispersed due to the high biological diversity and what food does exist is largely restricted to the canopy and requires considerable energy to obtain. Some groups of hunter-gatherers have exploited rainforest on a seasonal basis but dwelt primarily in adjacent savanna and open forest environments where food is much more abundant. Other people described as rainforest dwellers are hunter-gatherers who subsist in large part by trading high value forest products such as hides, feathers, and honey with agricultural people living outside the forest.

Indigenous peoples

Main article: Indigenous peoples
Members of an uncontacted tribe encountered in the Brazilian state of Acre in 2009

A variety of indigenous people live within the rainforest as hunter-gatherers, or subsist as part-time small scale farmers supplemented in large part by trading high-value forest products such as hides, feathers, and honey with agricultural people living outside the forest. Peoples have inhabited the rainforests for tens of thousands of years and have remained so elusive that only recently have some tribes been discovered. These indigenous peoples are greatly threatened by loggers in search for old-growth tropical hardwoods like Ipe, Cumaru and Wenge, and by farmers who are looking to expand their land, for cattle(meat), and soybeans, which are used to feed cattle in Europe and China. On 18 January 2007, FUNAI reported also that it had confirmed the presence of 67 different uncontacted tribes in Brazil, up from 40 in 2005. With this addition, Brazil has now overtaken the island of New Guinea as the country having the largest number of uncontacted tribes. The province of Irian Jaya or West Papua in the island of New Guinea is home to an estimated 44 uncontacted tribal groups.

Pygmy hunter-gatherers in the Congo Basin in 2014

The pygmy peoples are hunter-gatherer groups living in equatorial rainforests characterized by their short height (below one and a half meters, or 59 inches, on average). Amongst this group are the Efe, Aka, Twa, Baka, and Mbuti people of Central Africa. However, the term pygmy is considered pejorative so many tribes prefer not to be labeled as such.

Some notable indigenous peoples of the Americas, or Amerindians, include the Huaorani, Ya̧nomamö, and Kayapo people of the Amazon. The traditional agricultural system practiced by tribes in the Amazon is based on swidden cultivation (also known as slash-and-burn or shifting cultivation) and is considered a relatively benign disturbance. In fact, when looking at the level of individual swidden plots a number of traditional farming practices are considered beneficial. For example, the use of shade trees and fallowing all help preserve soil organic matter, which is a critical factor in the maintenance of soil fertility in the deeply weathered and leached soils common in the Amazon.

There is a diversity of forest people in Asia, including the Lumad peoples of the Philippines and the Penan and Dayak people of Borneo. The Dayaks are a particularly interesting group as they are noted for their traditional headhunting culture. Fresh human heads were required to perform certain rituals such as the Iban "kenyalang" and the Kenyah "mamat". Pygmies who live in Southeast Asia are, amongst others, referred to as "Negrito".

Resources

Cultivated foods and spices

Yam, coffee, chocolate, banana, mango, papaya, macadamia, avocado, and sugarcane all originally came from tropical rainforest and are still mostly grown on plantations in regions that were formerly primary forest. In the mid-1980s and 1990s, 40 million tons of bananas were consumed worldwide each year, along with 13 million tons of mango. Central American coffee exports were worth US$3 billion in 1970. Much of the genetic variation used in evading the damage caused by new pests is still derived from resistant wild stock. Tropical forests have supplied 250 cultivated kinds of fruit, compared to only 20 for temperate forests. Forests in New Guinea alone contain 251 tree species with edible fruits, of which only 43 had been established as cultivated crops by 1985.

Ecosystem services

Main article: ecosystem services

In addition to extractive human uses, rain forests also have non-extractive uses that are frequently summarized as ecosystem services. Rain forests play an important role in maintaining biological diversity, sequestering and storing carbon, global climate regulation, disease control, and pollination. Half of the rainfall in the Amazon area is produced by the forests. The moisture from the forests is important to the rainfall in Brazil, Paraguay, Argentina Deforestation in the Amazon rainforest region was one of the main reason that cause the severe Drought of 2014–2015 in Brazil For the last three decades, the amount of carbon absorbed by the world's intact tropical forests has fallen, according to a study published in 2020 in the journal Nature. In 2019 they took up a third less carbon than they did in the 1990s, due to higher temperatures, droughts and deforestation. The typical tropical forest may become a carbon source by the 2060s.

Tourism

Canopy walkway for seeing the diverse tropical forest in Costa Rica

Despite the negative effects of tourism in the tropical rainforests, there are also several important positive effects.

  • In recent years ecotourism in the tropics has increased. While rainforests are becoming increasingly rare, people are travelling to nations that still have this diverse habitat. Locals are benefiting from the additional income brought in by visitors, as well areas deemed interesting for visitors are often conserved. Ecotourism can be an incentive for conservation, especially when it triggers positive economic change. Ecotourism can include a variety of activities including animal viewing, scenic jungle tours and even viewing cultural sights and native villages. If these practices are performed appropriately this can be beneficial for both locals and the present flora and fauna.
  • An increase in tourism has increased economic support, allowing more revenue to go into the protection of the habitat. Tourism can contribute directly to the conservation of sensitive areas and habitat. Revenue from park-entrance fees and similar sources can be utilised specifically to pay for the protection and management of environmentally sensitive areas. Revenue from taxation and tourism provides an additional incentive for governments to contribute revenue to the protection of the forest.
  • Tourism also has the potential to increase public appreciation of the environment and to spread awareness of environmental problems when it brings people into closer contact with the environment. Such increased awareness can induce more environmentally conscious behavior. Tourism has had a positive effect on wildlife preservation and protection efforts, notably in Africa but also in South America, Asia, Australia, and the South Pacific.
Loss of primary (old-growth) forest in the tropics has continued its upward trend, with fire-related losses contributing an increasing portion.

Threats

Deforestation

Further information: Rainforest § Deforestation
Mining and drilling
The Ok Tedi Mine in southwestern Papua New Guinea

Deposits of precious metals (gold, silver, coltan) and fossil fuels (oil and natural gas) occur underneath rainforests globally. These resources are important to developing nations and their extraction is often given priority to encourage economic growth. Mining and drilling can require large amounts of land development, directly causing deforestation. In Ghana, a West African nation, deforestation from decades of mining activity left about 12% of the country's original rainforest intact.

Conversion to agricultural land

With the invention of agriculture, humans were able to clear sections of rainforest to produce crops, converting it to open farmland. Such people, however, obtain their food primarily from farm plots cleared from the forest and hunt and forage within the forest to supplement this. The issue arising is between the independent farmer providing for his family and the needs and wants of the globe as a whole. This issue has seen little improvement because no plan has been established for all parties to be aided.

Agriculture on formerly forested land is not without difficulties. Rainforest soils are often thin and leached of many minerals, and the heavy rainfall can quickly leach nutrients from area cleared for cultivation. People such as the Yanomamo of the Amazon, utilize slash-and-burn agriculture to overcome these limitations and enable them to push deep into what were previously rainforest environments. However, these are not rainforest dwellers, rather they are dwellers in cleared farmland that make forays into the rainforest. Up to 90% of the typical Yanamomo diet comes from farmed plants.

Some action has been taken by suggesting fallow periods of the land allowing secondary forest to grow and replenish the soil. Beneficial practices like soil restoration and conservation can benefit the small farmer and allow better production on smaller parcels of land.

Climate change

Main article: Climate change

The tropics take a major role in reducing atmospheric carbon dioxide. The tropics (most notably the Amazon rainforest) are called carbon sinks.[citation needed] As major carbon reducers and carbon and soil methane storages, their destruction contributes to increasing global energy trapping, atmospheric gases.[citation needed] Climate change has been significantly contributed to by the destruction of the rainforests. A simulation was performed in which all rainforest in Africa were removed. The simulation showed an increase in atmospheric temperature by 2.5 to 5 degrees Celsius.

Declining populations

Some species of fauna show a trend towards declining populations in rainforests, for example, reptiles that feed on amphibians and reptiles. This trend requires close monitoring. The seasonality of rainforests affects the reproductive patterns of amphibians, and this in turn can directly affect the species of reptiles that feed on these groups, particularly species with specialized feeding, since these are less likely to use alternative resources.

Protection

Efforts to protect and conserve tropical rainforest habitats are diverse and widespread. Tropical rainforest conservation ranges from strict preservation of habitat to finding sustainable management techniques for people living in tropical rainforests. International policy has also introduced a market incentive program called Reducing Emissions from Deforestation and Forest Degradation (REDD) for companies and governments to outset their carbon emissions through financial investments into rainforest conservation.

  1. Why the Amazon Rainforest is So Rich in Species Archived 25 February 2011 at the Wayback Machine. Earthobservatory.nasa.gov (5 December 2005). Retrieved on 28 March 2013.
  2. Why The Amazon Rainforest Is So Rich In Species. ScienceDaily.com (5 December 2005). Retrieved on 28 March 2013.
  3. Olson, David M.; Dinerstein, Eric; Wikramanayake, Eric D.; Burgess, Neil D.; Powell, George V. N.; Underwood, Emma C.; d'Amico, Jennifer A.; Itoua, Illanga; et al. (2001). "Terrestrial Ecoregions of the World: A New Map of Life on Earth". BioScience. 51 (11): 933–938. doi:10.1641/0006-3568(2001)051[0933:TEOTWA]2.0.CO;2.
  4. Woodward, Susan. Tropical broadleaf Evergreen Forest: The rainforest. Archived 25 February 2008 at the Wayback Machine Retrieved on 14 March 2009.
  5. Newman, Arnold (2002). Tropical Rainforest: Our Most Valuable and Endangered Habitat With a Blueprint for Its Survival into the Third Millennium (2 ed.). Checkmark. ISBN 0816039739.
  6. "Rainforests.net – Variables and Math". Archived from the original on 5 December 2008. Retrieved4 January 2009.
  7. The Regents of the University of Michigan. The Tropical Rain Forest. Retrieved on 14 March 2008.
  8. Rainforests Archived 8 July 2012 at the Wayback Machine. Animalcorner.co.uk (1 January 2004). Retrieved on 28 March 2013.
  9. The bite that heals. Ngm.nationalgeographic.com (25 February 2013). Retrieved on 24 June 2016.
  10. Sahney, S., Benton, M.J. & Falcon-Lang, H.J. (2010). "Rainforest collapse triggered Pennsylvanian tetrapod diversification in Euramerica". Geology. 38 (12): 1079–1082. Bibcode:2010Geo....38.1079S. doi:10.1130/G31182.1.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  11. Brazil: Deforestation rises sharply as farmers push into Amazon, The Guardian, 1 September 2008
  12. China is black hole of Asia's deforestation, Asia News, 24 March 2008
  13. Corlett, R. & Primack, R. (2006). "Tropical Rainforests and the Need for Cross-continental Comparisons". Trends in Ecology & Evolution. 21 (2): 104–110. doi:10.1016/j.tree.2005.12.002. PMID 16701482.
  14. Bruijnzeel, L. A. & Veneklaas, E. J. (1998). "Climatic Conditions and Tropical Montane Forest Productivity: The Fog Has Not Lifted Yet". Ecology. 79 (1): 3. doi:10.1890/0012-9658(1998)079[0003:CCATMF]2.0.CO;2.
  15. Bourgeron, Patrick S. (1983). "Spatial Aspects of Vegetation Structure". In Frank B. Golley (ed.). Tropical Rain Forest Ecosystems. Structure and Function. Ecosystems of the World (14A ed.). Elsevier Scientific. pp. 29–47. ISBN 0-444-41986-1.
  16. Webb, Len (1 October 1959). "A Physiognomic Classification of Australian Rain Forests". Journal of Ecology. British Ecological Society : Journal of Ecology Vol. 47, No. 3, pp. 551-570. 47 (3): 551–570. doi:10.2307/2257290. JSTOR 2257290.
  17. Erwin, T.L. (1982). "Tropical forests: Their richness in Coleoptera and other arthropod species"(PDF). The Coleopterists Bulletin. 36 (1): 74–75. JSTOR 4007977.
  18. "Sabah". Eastern Native Tree Society. Retrieved14 November 2007.
  19. King, David A. & Clark, Deborah A. (2011). "Allometry of Emergent Tree Species from Saplings to Above-canopy Adults in a Costa Rican Rain Forest". Journal of Tropical Ecology. 27 (6): 573–79. doi:10.1017/S0266467411000319. S2CID 8799184.
  20. Denslow, J S (1987). "Tropical Rainforest Gaps and Tree Species Diversity". Annual Review of Ecology and Systematics. 18: 431. doi:10.1146/annurev.es.18.110187.002243.
  21. Malhi, Yadvinder & Wright, James (2004). "Spatial patterns and recent trends in the climate of tropical rainforest regions". Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences. 359 (1443): 311–329. doi:10.1098/rstb.2003.1433. PMC1693325. PMID 15212087.
  22. Aragao, L. E. O. C. (2009). "Above- and below-ground net primary productivity across ten Amazonian forests on contrasting soils". Biogeosciences. 6 (12): 2759–2778. Bibcode:2009BGeo....6.2759A. doi:10.5194/bg-6-2759-2009.
  23. Moreira, A.; Fageria, N. K.; Garcia y Garcia, A. (2011). "Soil Fertility, Mineral Nitrogen, and Microbial Biomass in Upland Soils of the Central Amazon under Different Plant Covers"(PDF). Communications in Soil Science and Plant Analysis. 42 (6): 694–705. doi:10.1080/00103624.2011.550376. S2CID 73689568.
  24. Environmental news and information. mongabay.com. Retrieved on 28 March 2013.
  25. Cleveland, Cory C. & Townsend, Alan R. (2006). "Nutrient additions to a tropical rain forest drive substantial soil carbon dioxide losses to the atmosphere". PNAS. 103 (27): 10316–10321. Bibcode:2006PNAS..10310316C. doi:10.1073/pnas.0600989103. PMC1502455. PMID 16793925.
  26. Tang, Yong; Yang, Xiaofei; Cao, Min; Baskin, Carol C.; Baskin, Jerry M. (2010). "Buttress Trees Elevate Soil Heterogeneity and Regulate Seedling Diversity in a Tropical Rainforest"(PDF). Plant and Soil. 338 (1–2): 301–309. doi:10.1007/s11104-010-0546-4. S2CID 34892121.
  27. Sahney, S., Benton, M.J. and Ferry, P.A. (2010). "Links between global taxonomic diversity, ecological diversity and the expansion of vertebrates on land". Biology Letters. 6 (4): 544–547. doi:10.1098/rsbl.2009.1024. PMC2936204. PMID 20106856.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  28. Haffer, J. (1969). "Speciation in Amazonian Forest Birds". Science. 165 (131): 131–7. Bibcode:1969Sci...165..131H. doi:10.1126/science.165.3889.131. PMID 17834730.
  29. Moritz, C.; Patton, J. L.; Schneider, C. J.; Smith, T. B. (2000). "DIVERSIFICATION OF RAINFOREST FAUNAS: An Integrated Molecular Approach". Annu. Rev. Ecol. Syst. 31: 533. doi:10.1146/annurev.ecolsys.31.1.533.
  30. Barton, Huw; Denham, Tim; Neumann, Katharina; Arroyo-Kalin, Manuel (2012). "Long-term perspectives on human occupation of tropical rainforests: An introductory overview". Quaternary International. 249: 1–3. Bibcode:2012QuInt.249....1B. doi:10.1016/j.quaint.2011.07.044.
  31. Bailey, R.C., Head, G., Jenike, M., Owen, B., Rechtman, R., Zechenter, E. (1989). "Hunting and gathering in tropical rainforest: is it possible". American Anthropologist. 91 (1): 59–82. doi:10.1525/aa.1989.91.1.02a00040.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  32. 'They're killing us': world's most endangered tribe cries for help. The Guardian (22 April 2012). Retrieved on 24 June 2016.
  33. Sibaja, Marco (6 June 2012) Brazil's Indigenous Awa Tribe At Risk. Huffington Post
  34. González-Ruibal, Alfredo; Hernando, Almudena; Politis, Gustavo (2011). "Ontology of the self and material culture: Arrow-making among the Awá hunter–gatherers (Brazil)". Journal of Anthropological Archaeology. 30: 1. doi:10.1016/j.jaa.2010.10.001. hdl:10261/137811.
  35. Brazil sees traces of more isolated Amazon tribes. Reuters.com (17 January 2007). Retrieved on 28 March 2013.
  36. BBC: First contact with isolated tribes? survivalinternational.org (25 January 2007)
  37. "People of the Congo Rainforest". Mongabay.com. Retrieved11 August 2017.
  38. Forest peoples in the central African rain forest: focus on the pygmies. fao.org
  39. Dufour, D. R. (1990). "Use of tropical rainforest by native Amazonians"(PDF). BioScience. 40 (9): 652–659. doi:10.2307/1311432. JSTOR 1311432.
  40. Herrera, Rafael; Jordan, Carl F.; Medina, Ernesto & Klinge, Hans (1981). "How Human Activities Disturb the Nutrient Cycles of a Tropical Rainforest in Amazonia". Ambio. 10 (2/3, MAB: A Special Issue): 109–114. JSTOR 4312652.
  41. Ewel, J J (1986). "Designing Agricultural Ecosystems for the Humid Tropics". Annual Review of Ecology and Systematics. 17: 245–271. doi:10.1146/annurev.es.17.110186.001333. JSTOR 2096996.
  42. Jessup, T. C. & Vayda, A. P. (1988). "Dayaks and forests of interior Borneo"(PDF). Expedition. 30 (1): 5–17.
  43. Myers, N. (1985). The primary source, W. W. Norton and Co., New York, pp. 189–193, ISBN 0-393-30262-8
  44. Foley, Jonathan A.; Asner, Gregory P.; Costa, Marcos Heil; Coe, Michael T.; Defries, Ruth; Gibbs, Holly K.; Howard, Erica A.; Olson, Sarah; et al. (2007). "Amazonia revealed: forest degradation and loss of ecosystem goods and services in the Amazon Basin". Frontiers in Ecology and the Environment. 5 (1): 25–32. doi:10.1890/1540-9295(2007)5[25:ARFDAL]2.0.CO;2.
  45. E. Lovejoy, Thomas; Nobre, Carlos (21 February 2018). "Amazon Tipping Point". Science Advances. 4 (2): eaat2340. Bibcode:2018SciA....4.2340L. doi:10.1126/sciadv.aat2340. PMC5821491. PMID 29492460.
  46. Watts, Jonathan (28 November 2017). "The Amazon effect: how deforestation is starving São Paulo of water". The Guardian. Retrieved8 November 2018.
  47. VERCHOT, LOUIS (29 January 2015). "The science is clear: Forest loss behind Brazil's drought". Center for International Forestry Research (CIFOR). Retrieved8 November 2018.
  48. Harvey, Fiona (4 March 2020). "Tropical forests losing their ability to absorb carbon, study finds". The Guardian. ISSN 0261-3077. Retrieved5 March 2020.
  49. Stronza, A. & Gordillo, J. (2008). "Community views of ecotourism: Redefining benefits"(PDF). Annals of Tourism Research. 35 (2): 448. doi:10.1016/j.annals.2008.01.002.
  50. Fotiou, S. (October 2001). Environmental Impacts of Tourism. Retrieved 30 November 2007, from Uneptie.org Archived 28 December 2007 at the Wayback Machine
  51. "Forest Pulse: The Latest on the World's Forests". WRI.org. World Resources Institute. 28 April 2022. Archived from the original on 28 April 2022.
  52. Ismi, A. (1 October 2003), Canadian mining companies set to destroy Ghana’s forest reserves, Canadian Centre for Policy Alternatives Monitor, Ontario, Canada.
  53. Walker, Philip L.; Sugiyama, Larry and Chacon, Richard (1998) "Diet, Dental Health, and Cultural Change among Recently Contacted South American Indian Hunter-Horticulturalists", Ch. 17 in Human Dental Development, Morphology, and Pathology. University of Oregon Anthropological Papers, No. 54
  54. Tomich, P. T., Noordwijk, V. M., Vosti, A. S., Witcover, J (1998). "Agricultural development with rainforest conservation: methods for seeking best bet alternatives to slash-and-burn, with applications to Brazil and Indonesia"(PDF). Agricultural Economics. 19 (1–2): 159–174. doi:10.1016/S0169-5150(98)00032-2.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  55. De Jong, Wil; Freitas, Luis; Baluarte, Juan; Van De Kop, Petra; Salazar, Angel; Inga, Erminio; Melendez, Walter; Germaná, Camila (2001). "Secondary forest dynamics in the Amazon floodplain in Peru". Forest Ecology and Management. 150 (1–2): 135–146. doi:10.1016/S0378-1127(00)00687-3.
  56. Semazzi, F. H., Song, Y (2001). "A GCM study of climate change induced by deforestation in Africa". Climate Research. 17: 169–182. Bibcode:2001ClRes..17..169S. doi:10.3354/cr017169.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  57. Barquero-González, J.P., Stice, T.L., Gómez, G., & Monge- Nájera, J. 2020). Are tropical reptiles really declining? A six-year survey of snakes in a tropical coastal rainforest: role of prey and environment. Revista de Biología Tropical, 68(1), 336-343.
  58. Oliveira, M.E., & Martins, M. (2001). When and where to find a pitviper: activity patterns and habitat use of the lancehead, Bothrops atrox, in central Amazonia, Brazil. Herpetological Natural History, 8(2), 101-110.
  59. Terborgh, J., & Winter, B. (1980). Some causes of extinction. Conservation Biology, 2, 119-133.
  60. Varghese, Paul (August 2009). "An Overview of REDD, REDD Plus and REDD Readiness"(PDF). Archived from the original(PDF) on 14 July 2010. Retrieved23 November 2009.
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Tropical rainforest Article Talk Language Watch Edit This article s lead section may be too short to adequately summarize the key points Please consider expanding the lead to provide an accessible overview of all important aspects of the article June 2020 Tropical rainforests are rainforests that occur in areas of tropical rainforest climate in which there is no dry season all months have an average precipitation of at least 60 mm and may also be referred to as lowland equatorial evergreen rainforest True rainforests are typically found between 10 degrees north and south of the equator see map they are a sub set of the tropical forest biome that occurs roughly within the 28 degree latitudes in the equatorial zone between the Tropic of Cancer and Tropic of Capricorn Within the World Wildlife Fund s biome classification tropical rainforests are a type of tropical moist broadleaf forest or tropical wet forest that also includes the more extensive seasonal tropical forests 3 An area of the Amazon rainforest in Brazil The tropical rainforests of South America contain the largest diversity of species on Earth 1 2 Location of tropical dark green and temperate subtropical light green rainforests in the world Tropical rainforest climate zones Af Contents 1 Overview 1 1 History 1 2 Other types of tropical forest 2 Forest structure 2 1 Forest floor 2 2 Understory layer 2 3 Canopy layer 2 4 Emergent layer 3 Ecology 3 1 Climates 3 2 Soils 3 2 1 Soil types 3 2 2 Nutrient recycling 3 2 3 Buttress roots 3 3 Forest succession 4 Biodiversity and speciation 4 1 Interspecific competition 4 2 Pliestocene refugia 5 Human dimensions 5 1 Habitation 5 2 Indigenous peoples 5 3 Resources 5 3 1 Cultivated foods and spices 5 4 Ecosystem services 5 5 Tourism 6 Conservation 6 1 Threats 6 1 1 Deforestation 6 1 1 1 Mining and drilling 6 1 1 2 Conversion to agricultural land 6 1 2 Climate change 6 1 3 Declining populations 6 2 Protection 7 See also 8 References 9 External linksOverview Amazon River rain forest in Peru Tropical rainforests are characterized by two words hot and wet Mean monthly temperatures exceed 18 C 64 F during all months of the year 4 Average annual rainfall is no less than 1 680 mm 66 in and can exceed 10 m 390 in although it typically lies between 1 750 mm 69 in and 3 000 mm 120 in 5 This high level of precipitation often results in poor soils due to leaching of soluble nutrients in the ground Tropical rainforests exhibit high levels of biodiversity Around 40 to 75 of all biotic species are indigenous to the rainforests 6 Rainforests are home to half of all the living animal and plant species on the planet 7 Two thirds of all flowering plants can be found in rainforests 5 A single hectare of rainforest may contain 42 000 different species of insect up to 807 trees of 313 species and 1 500 species of higher plants 5 Tropical rainforests have been called the world s largest pharmacy because over one quarter of natural medicines have been discovered within them 8 9 It is likely that there may be many millions of species of plants insects and microorganisms still undiscovered in tropical rainforests Tropical rainforests are among the most threatened ecosystems globally due to large scale fragmentation as a result of human activity Habitat fragmentation caused by geological processes such as volcanism and climate change occurred in the past and have been identified as important drivers of speciation 10 However fast human driven habitat destruction is suspected to be one of the major causes of species extinction Tropical rain forests have been subjected to heavy logging and agricultural clearance throughout the 20th century and the area covered by rainforests around the world is rapidly shrinking 11 12 History Tropical rainforests have existed on earth for hundreds of millions of years Most tropical rainforests today are on fragments of the Mesozoic era supercontinent of Gondwana 13 The separation of the landmass resulted in a great loss of amphibian diversity while at the same time the drier climate spurred the diversification of reptiles 10 The division left tropical rainforests located in five major regions of the world tropical America Africa Southeast Asia Madagascar and New Guinea with smaller outliers in Australia 13 However the specifics of the origin of rainforests remain uncertain due to an incomplete fossil record Other types of tropical forest Main article Tropical forest Several biomes may appear similar to or merge via ecotones with tropical rainforest Hillawe Falls in the Hawaiian tropical rainforests in the United States Moist seasonal tropical forest Daintree rainforest in Queensland is actually a seasonal tropical forest Moist seasonal tropical forests receive high overall rainfall with a warm summer wet season and a cooler winter dry season Some trees in these forests drop some or all of their leaves during the winter dry season thus they are sometimes called tropical mixed forest They are found in parts of South America in Central America and around the Caribbean in coastal West Africa parts of the Indian subcontinent and across much of Indochina Montane rainforests These are found in cooler climate mountainous areas becoming known as cloud forests at higher elevations Depending on latitude the lower limit of montane rainforests on large mountains is generally between 1500 and 2500 m while the upper limit is usually from 2400 to 3300 m 14 Flooded rainforests Tropical freshwater swamp forests or flooded forests are found in Amazon basin the Varzea and elsewhere Forest structureRainforests are divided into different strata or layers with vegetation organized into a vertical pattern from the top of the soil to the canopy 15 Each layer is a unique biotic community containing different plants and animals adapted for life in that particular strata Only the emergent layer is unique to tropical rainforests while the others are also found in temperate rainforests 16 Forest floor Western lowland gorilla The forest floor the bottom most layer receives only 2 of the sunlight Only plants adapted to low light can grow in this region Away from riverbanks swamps and clearings where dense undergrowth is found the forest floor is relatively clear of vegetation because of the low sunlight penetration This more open quality permits the easy movement of larger animals such as ungulates like the okapi Okapia johnstoni tapir Tapirus sp Sumatran rhinoceros Dicerorhinus sumatrensis and apes like the western lowland gorilla Gorilla gorilla as well as many species of reptiles amphibians and insects The forest floor also contains decaying plant and animal matter which disappears quickly because the warm humid conditions promote rapid decay Many forms of fungi growing here help decay the animal and plant waste Understory layer Main article Understory The understory layer lies between the canopy and the forest floor The understory is home to a number of birds small mammals insects reptiles and predators Examples include leopard Panthera pardus poison dart frogs Dendrobates sp ring tailed coati Nasua nasua boa constrictor Boa constrictor and many species of Coleoptera 5 The vegetation at this layer generally consists of shade tolerant shrubs herbs small trees and large woody vines which climb into the trees to capture sunlight Only about 5 of sunlight breaches the canopy to arrive at the understory causing true understory plants to seldom grow to 3 m 10 feet As an adaptation to these low light levels understory plants have often evolved much larger leaves Many seedlings that will grow to the canopy level are in the understory The canopy at the Forest Research Institute Malaysia Canopy layer Main article Canopy ecology The canopy is the primary layer of the forest forming a roof over the two remaining layers It contains the majority of the largest trees typically 30 45 m in height Tall broad leaved evergreen trees are the dominant plants The densest areas of biodiversity are found in the forest canopy as it often supports a rich flora of epiphytes including orchids bromeliads mosses and lichens These epiphytic plants attach to trunks and branches and obtain water and minerals from rain and debris that collects on the supporting plants The fauna is similar to that found in the emergent layer but more diverse It is suggested that the total arthropod species richness of the tropical canopy might be as high as 20 million 17 Other species habituating this layer include many avian species such as the yellow casqued wattled hornbill Ceratogymna elata collared sunbird Anthreptes collaris grey parrot Psitacus erithacus keel billed toucan Ramphastos sulfuratus scarlet macaw Ara macao as well as other animals like the spider monkey Ateles sp African giant swallowtail Papilio antimachus three toed sloth Bradypus tridactylus kinkajou Potos flavus and tamandua Tamandua tetradactyla 5 Emergent layer The emergent layer contains a small number of very large trees called emergents which grow above the general canopy reaching heights of 45 55 m although on occasion a few species will grow to 70 80 m tall 15 18 Some examples of emergents include Balizia elegans Dipteryx panamensis Hieronyma alchorneoides Hymenolobium mesoamericanum Lecythis ampla and Terminalia oblonga 19 These trees need to be able to withstand the hot temperatures and strong winds that occur above the canopy in some areas Several unique faunal species inhabit this layer such as the crowned eagle Stephanoaetus coronatus the king colobus Colobus polykomos and the large flying fox Pteropus vampyrus 5 However stratification is not always clear Rainforests are dynamic and many changes affect the structure of the forest Emergent or canopy trees collapse for example causing gaps to form Openings in the forest canopy are widely recognized as important for the establishment and growth of rainforest trees It is estimated that perhaps 75 of the tree species at La Selva Biological Station Costa Rica are dependent on canopy opening for seed germination or for growth beyond sapling size for example 20 EcologyClimates Artificial tropical rainforest in Barcelona Tropical rainforests are located around and near the equator therefore having what is called an equatorial climate characterized by three major climatic parameters temperature rainfall and dry season intensity 21 Other parameters that affect tropical rainforests are carbon dioxide concentrations solar radiation and nitrogen availability In general climatic patterns consist of warm temperatures and high annual rainfall However the abundance of rainfall changes throughout the year creating distinct moist and dry seasons Tropical forests are classified by the amount of rainfall received each year which has allowed ecologists to define differences in these forests that look so similar in structure According to Holdridge s classification of tropical ecosystems true tropical rainforests have an annual rainfall greater than 2 m and annual temperature greater than 24 degrees Celsius with a potential evapotranspiration ratio PET value of lt 0 25 However most lowland tropical forests can be classified as tropical moist or wet forests which differ in regards to rainfall Tropical forest ecology dynamics composition and function are sensitive to changes in climate especially changes in rainfall 21 Soils Soil types Soil types are highly variable in the tropics and are the result of a combination of several variables such as climate vegetation topographic position parent material and soil age 22 Most tropical soils are characterized by significant leaching and poor nutrients however there are some areas that contain fertile soils Soils throughout the tropical rainforests fall into two classifications which include the ultisols and oxisols Ultisols are known as well weathered acidic red clay soils deficient in major nutrients such as calcium and potassium Similarly oxisols are acidic old typically reddish highly weathered and leached however are well drained compared to ultisols The clay content of ultisols is high making it difficult for water to penetrate and flow through The reddish color of both soils is the result of heavy heat and moisture forming oxides of iron and aluminium which are insoluble in water and not taken up readily by plants Soil chemical and physical characteristics are strongly related to above ground productivity and forest structure and dynamics The physical properties of soil control the tree turnover rates whereas chemical properties such as available nitrogen and phosphorus control forest growth rates 23 The soils of the eastern and central Amazon as well as the Southeast Asian Rainforest are old and mineral poor whereas the soils of the western Amazon Ecuador and Peru and volcanic areas of Costa Rica are young and mineral rich Primary productivity or wood production is highest in western Amazon and lowest in eastern Amazon which contains heavily weathered soils classified as oxisols 22 Additionally Amazonian soils are greatly weathered making them devoid of minerals like phosphorus potassium calcium and magnesium which come from rock sources However not all tropical rainforests occur on nutrient poor soils but on nutrient rich floodplains and volcanic soils located in the Andean foothills and volcanic areas of Southeast Asia Africa and Central America 24 Oxisols infertile deeply weathered and severely leached have developed on the ancient Gondwanan shields Rapid bacterial decay prevents the accumulation of humus The concentration of iron and aluminium oxides by the laterization process gives the oxisols a bright red color and sometimes produces minable deposits e g bauxite On younger substrates especially of volcanic origin tropical soils may be quite fertile Nutrient recycling This high rate of decomposition is the result of phosphorus levels in the soils precipitation high temperatures and the extensive microorganism communities 25 In addition to the bacteria and other microorganisms there are an abundance of other decomposers such as fungi and termites that aid in the process as well Nutrient recycling is important because below ground resource availability controls the above ground biomass and community structure of tropical rainforests These soils are typically phosphorus limited which inhibits net primary productivity or the uptake of carbon 22 The soil contains microbial organisms such as bacteria which break down leaf litter and other organic matter into inorganic forms of carbon usable by plants through a process called decomposition During the decomposition process the microbial community is respiring taking up oxygen and releasing carbon dioxide The decomposition rate can be evaluated by measuring the uptake of oxygen 25 High temperatures and precipitation increase decomposition rate which allows plant litter to rapidly decay in tropical regions releasing nutrients that are immediately taken up by plants through surface or ground waters The seasonal patterns in respiration are controlled by leaf litter fall and precipitation the driving force moving the decomposable carbon from the litter to the soil Respiration rates are highest early in the wet season because the recent dry season results in a large percentage of leaf litter and thus a higher percentage of organic matter being leached into the soil 25 Buttress roots A common feature of many tropical rainforests is the distinct buttress roots of trees Instead of penetrating to deeper soil layers buttress roots create a widespread root network at the surface for more efficient uptake of nutrients in a very nutrient poor and competitive environment Most of the nutrients within the soil of a tropical rainforest occur near the surface because of the rapid turnover time and decomposition of organisms and leaves 26 Because of this the buttress roots occur at the surface so the trees can maximize uptake and actively compete with the rapid uptake of other trees These roots also aid in water uptake and storage increase surface area for gas exchange and collect leaf litter for added nutrition 26 Additionally these roots reduce soil erosion and maximize nutrient acquisition during heavy rains by diverting nutrient rich water flowing down the trunk into several smaller flows while also acting as a barrier to ground flow Also the large surface areas these roots create provide support and stability to rainforests trees which commonly grow to significant heights This added stability allows these trees to withstand the impacts of severe storms thus reducing the occurrence of fallen trees 26 Forest succession Succession is an ecological process that changes the biotic community structure over time towards a more stable diverse community structure after an initial disturbance to the community The initial disturbance is often a natural phenomenon or human caused event Natural disturbances include hurricanes volcanic eruptions river movements or an event as small as a fallen tree that creates gaps in the forest In tropical rainforests these same natural disturbances have been well documented in the fossil record and are credited with encouraging speciation and endemism 10 Human land use practices have led to large scale deforestation In many tropical countries such as Costa Rica these deforested lands have been abandoned and forests have been allowed to regenerate through ecological succession These regenerating young successional forests are called secondary forests or second growth forests Biodiversity and speciationThis section needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed November 2013 Learn how and when to remove this template message Young orangutan at Bukit Lawang Sumatra Tropical rainforests exhibit a vast diversity in plant and animal species The root for this remarkable speciation has been a query of scientists and ecologists for years A number of theories have been developed for why and how the tropics can be so diverse Interspecific competition Interspecific competition results from a high density of species with similar niches in the tropics and limited resources available Species which lose the competition may either become extinct or find a new niche Direct competition will often lead to one species dominating another by some advantage ultimately driving it to extinction Niche partitioning is the other option for a species This is the separation and rationing of necessary resources by utilizing different habitats food sources cover or general behavioral differences A species with similar food items but different feeding times is an example of niche partitioning 27 Pliestocene refugia The theory of Pleistocene refugia was developed by Jurgen Haffer in 1969 with his article Speciation of Amazonian Forest Birds Haffer proposed the explanation for speciation was the product of rainforest patches being separated by stretches of non forest vegetation during the last glacial period He called these patches of rainforest areas refuges and within these patches allopatric speciation occurred With the end of the glacial period and increase in atmospheric humidity rainforest began to expand and the refuges reconnected 28 This theory has been the subject of debate Scientists are still skeptical of whether or not this theory is legitimate Genetic evidence suggests speciation had occurred in certain taxa 1 2 million years ago preceding the Pleistocene 29 Human dimensionsHabitation Tropical rainforests have harboured human life for many millennia with many Indian tribes in South and Central America who belong to the Indigenous peoples of the Americas the Congo Pygmies in Central Africa and several tribes in South East Asia like the Dayak people and the Penan people in Borneo 30 Food resources within the forest are extremely dispersed due to the high biological diversity and what food does exist is largely restricted to the canopy and requires considerable energy to obtain Some groups of hunter gatherers have exploited rainforest on a seasonal basis but dwelt primarily in adjacent savanna and open forest environments where food is much more abundant Other people described as rainforest dwellers are hunter gatherers who subsist in large part by trading high value forest products such as hides feathers and honey with agricultural people living outside the forest 31 Indigenous peoples Main article Indigenous peoples Members of an uncontacted tribe encountered in the Brazilian state of Acre in 2009 A variety of indigenous people live within the rainforest as hunter gatherers or subsist as part time small scale farmers supplemented in large part by trading high value forest products such as hides feathers and honey with agricultural people living outside the forest 30 31 Peoples have inhabited the rainforests for tens of thousands of years and have remained so elusive that only recently have some tribes been discovered 30 These indigenous peoples are greatly threatened by loggers in search for old growth tropical hardwoods like Ipe Cumaru and Wenge and by farmers who are looking to expand their land for cattle meat and soybeans which are used to feed cattle in Europe and China 30 32 33 34 On 18 January 2007 FUNAI reported also that it had confirmed the presence of 67 different uncontacted tribes in Brazil up from 40 in 2005 With this addition Brazil has now overtaken the island of New Guinea as the country having the largest number of uncontacted tribes 35 The province of Irian Jaya or West Papua in the island of New Guinea is home to an estimated 44 uncontacted tribal groups 36 Pygmy hunter gatherers in the Congo Basin in 2014 The pygmy peoples are hunter gatherer groups living in equatorial rainforests characterized by their short height below one and a half meters or 59 inches on average Amongst this group are the Efe Aka Twa Baka and Mbuti people of Central Africa 37 However the term pygmy is considered pejorative so many tribes prefer not to be labeled as such 38 Some notable indigenous peoples of the Americas or Amerindians include the Huaorani Ya nomamo and Kayapo people of the Amazon The traditional agricultural system practiced by tribes in the Amazon is based on swidden cultivation also known as slash and burn or shifting cultivation and is considered a relatively benign disturbance 39 40 In fact when looking at the level of individual swidden plots a number of traditional farming practices are considered beneficial For example the use of shade trees and fallowing all help preserve soil organic matter which is a critical factor in the maintenance of soil fertility in the deeply weathered and leached soils common in the Amazon 41 There is a diversity of forest people in Asia including the Lumad peoples of the Philippines and the Penan and Dayak people of Borneo The Dayaks are a particularly interesting group as they are noted for their traditional headhunting culture Fresh human heads were required to perform certain rituals such as the Iban kenyalang and the Kenyah mamat 42 Pygmies who live in Southeast Asia are amongst others referred to as Negrito Resources Cultivated foods and spices Yam coffee chocolate banana mango papaya macadamia avocado and sugarcane all originally came from tropical rainforest and are still mostly grown on plantations in regions that were formerly primary forest In the mid 1980s and 1990s 40 million tons of bananas were consumed worldwide each year along with 13 million tons of mango Central American coffee exports were worth US 3 billion in 1970 Much of the genetic variation used in evading the damage caused by new pests is still derived from resistant wild stock Tropical forests have supplied 250 cultivated kinds of fruit compared to only 20 for temperate forests Forests in New Guinea alone contain 251 tree species with edible fruits of which only 43 had been established as cultivated crops by 1985 43 Ecosystem services Main article ecosystem services In addition to extractive human uses rain forests also have non extractive uses that are frequently summarized as ecosystem services Rain forests play an important role in maintaining biological diversity sequestering and storing carbon global climate regulation disease control and pollination 44 Half of the rainfall in the Amazon area is produced by the forests The moisture from the forests is important to the rainfall in Brazil Paraguay Argentina 45 Deforestation in the Amazon rainforest region was one of the main reason that cause the severe Drought of 2014 2015 in Brazil 46 47 For the last three decades the amount of carbon absorbed by the world s intact tropical forests has fallen according to a study published in 2020 in the journal Nature In 2019 they took up a third less carbon than they did in the 1990s due to higher temperatures droughts and deforestation The typical tropical forest may become a carbon source by the 2060s 48 Tourism Canopy walkway for seeing the diverse tropical forest in Costa Rica Despite the negative effects of tourism in the tropical rainforests there are also several important positive effects In recent years ecotourism in the tropics has increased While rainforests are becoming increasingly rare people are travelling to nations that still have this diverse habitat Locals are benefiting from the additional income brought in by visitors as well areas deemed interesting for visitors are often conserved Ecotourism can be an incentive for conservation especially when it triggers positive economic change 49 Ecotourism can include a variety of activities including animal viewing scenic jungle tours and even viewing cultural sights and native villages If these practices are performed appropriately this can be beneficial for both locals and the present flora and fauna An increase in tourism has increased economic support allowing more revenue to go into the protection of the habitat Tourism can contribute directly to the conservation of sensitive areas and habitat Revenue from park entrance fees and similar sources can be utilised specifically to pay for the protection and management of environmentally sensitive areas Revenue from taxation and tourism provides an additional incentive for governments to contribute revenue to the protection of the forest Tourism also has the potential to increase public appreciation of the environment and to spread awareness of environmental problems when it brings people into closer contact with the environment Such increased awareness can induce more environmentally conscious behavior Tourism has had a positive effect on wildlife preservation and protection efforts notably in Africa but also in South America Asia Australia and the South Pacific 50 Conservation Loss of primary old growth forest in the tropics has continued its upward trend with fire related losses contributing an increasing portion 51 Threats Deforestation Further information Rainforest Deforestation Mining and drilling The Ok Tedi Mine in southwestern Papua New Guinea Deposits of precious metals gold silver coltan and fossil fuels oil and natural gas occur underneath rainforests globally These resources are important to developing nations and their extraction is often given priority to encourage economic growth Mining and drilling can require large amounts of land development directly causing deforestation In Ghana a West African nation deforestation from decades of mining activity left about 12 of the country s original rainforest intact 52 Conversion to agricultural land With the invention of agriculture humans were able to clear sections of rainforest to produce crops converting it to open farmland Such people however obtain their food primarily from farm plots cleared from the forest 31 53 and hunt and forage within the forest to supplement this The issue arising is between the independent farmer providing for his family and the needs and wants of the globe as a whole This issue has seen little improvement because no plan has been established for all parties to be aided 54 Agriculture on formerly forested land is not without difficulties Rainforest soils are often thin and leached of many minerals and the heavy rainfall can quickly leach nutrients from area cleared for cultivation People such as the Yanomamo of the Amazon utilize slash and burn agriculture to overcome these limitations and enable them to push deep into what were previously rainforest environments However these are not rainforest dwellers rather they are dwellers in cleared farmland 31 53 that make forays into the rainforest Up to 90 of the typical Yanamomo diet comes from farmed plants 53 Some action has been taken by suggesting fallow periods of the land allowing secondary forest to grow and replenish the soil 55 Beneficial practices like soil restoration and conservation can benefit the small farmer and allow better production on smaller parcels of land Climate change Main article Climate change The tropics take a major role in reducing atmospheric carbon dioxide The tropics most notably the Amazon rainforest are called carbon sinks citation needed As major carbon reducers and carbon and soil methane storages their destruction contributes to increasing global energy trapping atmospheric gases citation needed Climate change has been significantly contributed to by the destruction of the rainforests A simulation was performed in which all rainforest in Africa were removed The simulation showed an increase in atmospheric temperature by 2 5 to 5 degrees Celsius 56 Declining populations Some species of fauna show a trend towards declining populations in rainforests for example reptiles that feed on amphibians and reptiles This trend requires close monitoring 57 The seasonality of rainforests affects the reproductive patterns of amphibians and this in turn can directly affect the species of reptiles that feed on these groups 58 particularly species with specialized feeding since these are less likely to use alternative resources 59 Protection Efforts to protect and conserve tropical rainforest habitats are diverse and widespread Tropical rainforest conservation ranges from strict preservation of habitat to finding sustainable management techniques for people living in tropical rainforests International policy has also introduced a market incentive program called Reducing Emissions from Deforestation and Forest Degradation REDD for companies and governments to outset their carbon emissions through financial investments into rainforest conservation 60 See alsoInternational Tropical Timber Organization List of tropical and subtropical moist broadleaf forests ecoregions Palaeogeography Rainforest Temperate rainforest Tropical Africa Tropical Asia Tropical forest Tropical and subtropical moist broadleaf forests Tropical rainforest climate Tropical vegetationReferences Why the Amazon Rainforest is So Rich in Species Archived 25 February 2011 at the Wayback Machine Earthobservatory nasa gov 5 December 2005 Retrieved on 28 March 2013 Why The Amazon Rainforest Is So Rich In Species ScienceDaily com 5 December 2005 Retrieved on 28 March 2013 Olson David M Dinerstein Eric Wikramanayake Eric D Burgess Neil D Powell George V N Underwood Emma C d Amico Jennifer A Itoua Illanga et al 2001 Terrestrial Ecoregions of the World A New Map of Life on Earth BioScience 51 11 933 938 doi 10 1641 0006 3568 2001 051 0933 TEOTWA 2 0 CO 2 Woodward Susan Tropical broadleaf Evergreen Forest The rainforest Archived 25 February 2008 at the Wayback Machine Retrieved on 14 March 2009 a b c d e f Newman Arnold 2002 Tropical Rainforest Our Most Valuable and Endangered Habitat With a Blueprint for Its Survival into the Third Millennium 2 ed Checkmark ISBN 0816039739 Rainforests net Variables and Math Archived from the original on 5 December 2008 Retrieved 4 January 2009 The Regents of the University of Michigan The Tropical Rain Forest Retrieved on 14 March 2008 Rainforests Archived 8 July 2012 at the Wayback Machine Animalcorner co uk 1 January 2004 Retrieved on 28 March 2013 The bite that heals Ngm nationalgeographic com 25 February 2013 Retrieved on 24 June 2016 a b c Sahney S Benton M J amp Falcon Lang H J 2010 Rainforest collapse triggered Pennsylvanian tetrapod diversification in Euramerica Geology 38 12 1079 1082 Bibcode 2010Geo 38 1079S doi 10 1130 G31182 1 a href wiki Template Cite journal title Template Cite journal cite journal a CS1 maint multiple names authors list link Brazil Deforestation rises sharply as farmers push into Amazon The Guardian 1 September 2008 China is black hole of Asia s deforestation Asia News 24 March 2008 a b Corlett R amp Primack R 2006 Tropical Rainforests and the Need for Cross continental Comparisons Trends in Ecology amp Evolution 21 2 104 110 doi 10 1016 j tree 2005 12 002 PMID 16701482 Bruijnzeel L A amp Veneklaas E J 1998 Climatic Conditions and Tropical Montane Forest Productivity The Fog Has Not Lifted Yet Ecology 79 1 3 doi 10 1890 0012 9658 1998 079 0003 CCATMF 2 0 CO 2 a b Bourgeron Patrick S 1983 Spatial Aspects of Vegetation Structure In Frank B Golley ed Tropical Rain Forest Ecosystems Structure and Function Ecosystems of the World 14A ed Elsevier Scientific pp 29 47 ISBN 0 444 41986 1 Webb Len 1 October 1959 A Physiognomic Classification of Australian Rain Forests Journal of Ecology British Ecological Society Journal of Ecology Vol 47 No 3 pp 551 570 47 3 551 570 doi 10 2307 2257290 JSTOR 2257290 Erwin T L 1982 Tropical forests Their richness in Coleoptera and other arthropod species PDF The Coleopterists Bulletin 36 1 74 75 JSTOR 4007977 Sabah Eastern Native Tree Society Retrieved 14 November 2007 King David A amp Clark Deborah A 2011 Allometry of Emergent Tree Species from Saplings to Above canopy Adults in a Costa Rican Rain Forest Journal of Tropical Ecology 27 6 573 79 doi 10 1017 S0266467411000319 S2CID 8799184 Denslow J S 1987 Tropical Rainforest Gaps and Tree Species Diversity Annual Review of Ecology and Systematics 18 431 doi 10 1146 annurev es 18 110187 002243 a b Malhi Yadvinder amp Wright James 2004 Spatial patterns and recent trends in the climate of tropical rainforest regions Philosophical Transactions of the Royal Society of London Series B Biological Sciences 359 1443 311 329 doi 10 1098 rstb 2003 1433 PMC 1693325 PMID 15212087 a b c Aragao L E O C 2009 Above and below ground net primary productivity across ten Amazonian forests on contrasting soils Biogeosciences 6 12 2759 2778 Bibcode 2009BGeo 6 2759A doi 10 5194 bg 6 2759 2009 Moreira A Fageria N K Garcia y Garcia A 2011 Soil Fertility Mineral Nitrogen and Microbial Biomass in Upland Soils of the Central Amazon under Different Plant Covers PDF Communications in Soil Science and Plant Analysis 42 6 694 705 doi 10 1080 00103624 2011 550376 S2CID 73689568 Environmental news and information mongabay com Retrieved on 28 March 2013 a b c Cleveland Cory C amp Townsend Alan R 2006 Nutrient additions to a tropical rain forest drive substantial soil carbon dioxide losses to the atmosphere PNAS 103 27 10316 10321 Bibcode 2006PNAS 10310316C doi 10 1073 pnas 0600989103 PMC 1502455 PMID 16793925 a b c Tang Yong Yang Xiaofei Cao Min Baskin Carol C Baskin Jerry M 2010 Buttress Trees Elevate Soil Heterogeneity and Regulate Seedling Diversity in a Tropical Rainforest PDF Plant and Soil 338 1 2 301 309 doi 10 1007 s11104 010 0546 4 S2CID 34892121 Sahney S Benton M J and Ferry P A 2010 Links between global taxonomic diversity ecological diversity and the expansion of vertebrates on land Biology Letters 6 4 544 547 doi 10 1098 rsbl 2009 1024 PMC 2936204 PMID 20106856 a href wiki Template Cite journal title Template Cite journal cite journal a CS1 maint multiple names authors list link Haffer J 1969 Speciation in Amazonian Forest Birds Science 165 131 131 7 Bibcode 1969Sci 165 131H doi 10 1126 science 165 3889 131 PMID 17834730 Moritz C Patton J L Schneider C J Smith T B 2000 DIVERSIFICATION OF RAINFOREST FAUNAS An Integrated Molecular Approach Annu Rev Ecol Syst 31 533 doi 10 1146 annurev ecolsys 31 1 533 a b c d Barton Huw Denham Tim Neumann Katharina Arroyo Kalin Manuel 2012 Long term perspectives on human occupation of tropical rainforests An introductory overview Quaternary International 249 1 3 Bibcode 2012QuInt 249 1B doi 10 1016 j quaint 2011 07 044 a b c d Bailey R C Head G Jenike M Owen B Rechtman R Zechenter E 1989 Hunting and gathering in tropical rainforest is it possible American Anthropologist 91 1 59 82 doi 10 1525 aa 1989 91 1 02a00040 a href wiki Template Cite journal title Template Cite journal cite journal a CS1 maint multiple names authors list link They re killing us world s most endangered tribe cries for help The Guardian 22 April 2012 Retrieved on 24 June 2016 Sibaja Marco 6 June 2012 Brazil s Indigenous Awa Tribe At Risk Huffington Post Gonzalez Ruibal Alfredo Hernando Almudena Politis Gustavo 2011 Ontology of the self and material culture Arrow making among the Awa hunter gatherers Brazil Journal of Anthropological Archaeology 30 1 doi 10 1016 j jaa 2010 10 001 hdl 10261 137811 Brazil sees traces of more isolated Amazon tribes Reuters com 17 January 2007 Retrieved on 28 March 2013 BBC First contact with isolated tribes survivalinternational org 25 January 2007 People of the Congo Rainforest Mongabay com Retrieved 11 August 2017 Forest peoples in the central African rain forest focus on the pygmies fao org Dufour D R 1990 Use of tropical rainforest by native Amazonians PDF BioScience 40 9 652 659 doi 10 2307 1311432 JSTOR 1311432 Herrera Rafael Jordan Carl F Medina Ernesto amp Klinge Hans 1981 How Human Activities Disturb the Nutrient Cycles of a Tropical Rainforest in Amazonia Ambio 10 2 3 MAB A Special Issue 109 114 JSTOR 4312652 Ewel J J 1986 Designing Agricultural Ecosystems for the Humid Tropics Annual Review of Ecology and Systematics 17 245 271 doi 10 1146 annurev es 17 110186 001333 JSTOR 2096996 Jessup T C amp Vayda A P 1988 Dayaks and forests of interior Borneo PDF Expedition 30 1 5 17 Myers N 1985 The primary source W W Norton and Co New York pp 189 193 ISBN 0 393 30262 8 Foley Jonathan A Asner Gregory P Costa Marcos Heil Coe Michael T Defries Ruth Gibbs Holly K Howard Erica A Olson Sarah et al 2007 Amazonia revealed forest degradation and loss of ecosystem goods and services in the Amazon Basin Frontiers in Ecology and the Environment 5 1 25 32 doi 10 1890 1540 9295 2007 5 25 ARFDAL 2 0 CO 2 E Lovejoy Thomas Nobre Carlos 21 February 2018 Amazon Tipping Point Science Advances 4 2 eaat2340 Bibcode 2018SciA 4 2340L doi 10 1126 sciadv aat2340 PMC 5821491 PMID 29492460 Watts Jonathan 28 November 2017 The Amazon effect how deforestation is starving Sao Paulo of water The Guardian Retrieved 8 November 2018 VERCHOT LOUIS 29 January 2015 The science is clear Forest loss behind Brazil s drought Center for International Forestry Research CIFOR Retrieved 8 November 2018 Harvey Fiona 4 March 2020 Tropical forests losing their ability to absorb carbon study finds The Guardian ISSN 0261 3077 Retrieved 5 March 2020 Stronza A amp Gordillo J 2008 Community views of ecotourism Redefining benefits PDF Annals of Tourism Research 35 2 448 doi 10 1016 j annals 2008 01 002 Fotiou S October 2001 Environmental Impacts of Tourism Retrieved 30 November 2007 from Uneptie org Archived 28 December 2007 at the Wayback Machine Forest Pulse The Latest on the World s Forests WRI org World Resources Institute 28 April 2022 Archived from the original on 28 April 2022 Ismi A 1 October 2003 Canadian mining companies set to destroy Ghana s forest reserves Canadian Centre for Policy Alternatives Monitor Ontario Canada a b c Walker Philip L Sugiyama Larry and Chacon Richard 1998 Diet Dental Health and Cultural Change among Recently Contacted South American Indian Hunter Horticulturalists Ch 17 in Human Dental Development Morphology and Pathology University of Oregon Anthropological Papers No 54 Tomich P T Noordwijk V M Vosti A S Witcover J 1998 Agricultural development with rainforest conservation methods for seeking best bet alternatives to slash and burn with applications to Brazil and Indonesia PDF Agricultural Economics 19 1 2 159 174 doi 10 1016 S0169 5150 98 00032 2 a href wiki Template Cite journal title Template Cite journal cite journal a CS1 maint multiple names authors list link De Jong Wil Freitas Luis Baluarte Juan Van De Kop Petra Salazar Angel Inga Erminio Melendez Walter Germana Camila 2001 Secondary forest dynamics in the Amazon floodplain in Peru Forest Ecology and Management 150 1 2 135 146 doi 10 1016 S0378 1127 00 00687 3 Semazzi F H Song Y 2001 A GCM study of climate change induced by deforestation in Africa Climate Research 17 169 182 Bibcode 2001ClRes 17 169S doi 10 3354 cr017169 a href wiki Template Cite journal title Template Cite journal cite journal a CS1 maint multiple names authors list link Barquero Gonzalez J P Stice T L Gomez G amp Monge Najera J 2020 Are tropical reptiles really declining A six year survey of snakes in a tropical coastal rainforest role of prey and environment Revista de Biologia Tropical 68 1 336 343 Oliveira M E amp Martins M 2001 When and where to find a pitviper activity patterns and habitat use of the lancehead Bothrops atrox in central Amazonia Brazil Herpetological Natural History 8 2 101 110 Terborgh J amp Winter B 1980 Some causes of extinction Conservation Biology 2 119 133 Varghese Paul August 2009 An Overview of REDD REDD Plus and REDD Readiness PDF Archived from the original PDF on 14 July 2010 Retrieved 23 November 2009 External linksWikimedia Commons has media related to Tropical rainforests Wikivoyage has a travel guide for Tropical rainforests Rainforest Action Network Rain Forest Info from Blue Planet Biomes Passport to Knowledge Rainforests Tropical Forests Project Regeneration 2021 Retrieved from https en wikipedia org w index php title Tropical rainforest amp oldid 1093929011, wikipedia, wiki, book,

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