Editing Tropical rainforest (section)

== Overview ==
[[File:Rio Madre de Dios, Peru.JPG|thumb|left|[[Amazon River]] rain forest in [[Peru]]]]

Tropical rainforests are hot and wet. Mean monthly temperatures exceed {{convert|18|C|F}} during all months of the year.<ref>Woodward, Susan. [http://www.radford.edu/~swoodwar/CLASSES/GEOG235/biomes/rainforest/rainfrst.html Tropical broadleaf Evergreen Forest: The rainforest.] {{webarchive|url=https://web.archive.org/web/20080225054655/http://www.radford.edu/~swoodwar/CLASSES/GEOG235/biomes/rainforest/rainfrst.html |date=25 February 2008 }} Retrieved on 14 March 2009.</ref> Average annual rainfall is no less than {{convert|1680|mm|in|abbr=on}} and can exceed {{convert|10|m|in|abbr=on}} although it typically lies between {{convert|1750|mm|in|abbr=on}} and {{convert|3000|mm|in|abbr=on}}.<ref name="Newman, Arnold 2002">{{cite book|last=Newman|first=Arnold|title=Tropical Rainforest: Our Most Valuable and Endangered Habitat With a Blueprint for Its Survival into the Third Millennium|year=2002|publisher=Checkmark|isbn=0816039739|edition=2|url=https://archive.org/details/tropicalrainfore00newm_0}}</ref> This high level of [[precipitation]] often results in poor [[soil]]s due to [[leaching (agriculture)|leaching]] of soluble nutrients in the ground.

Tropical rainforests exhibit high levels of biodiversity. Around 40% to 75% of all biotic [[species]] are [[Indigenous (ecology)|indigenous]] to the rainforests.<ref name=Variables>{{cite web|url=http://www.rainforests.net/variables.htm |title=Rainforests.net – Variables and Math |access-date=4 January 2009 |url-status=dead |archive-url=https://web.archive.org/web/20081205135329/http://www.rainforests.net/variables.htm |archive-date=5 December 2008 }}</ref> Rainforests are home to half of all the living animal and plant species on the planet.<ref name="MI">The Regents of the [[University of Michigan]]. [http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/rainforest/rainforest.html The Tropical Rain Forest.] Retrieved on 14 March 2008.</ref> Two-thirds of all flowering plants can be found in rainforests.<ref name="Newman, Arnold 2002" /> 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.<ref name="Newman, Arnold 2002" /> Tropical rainforests have been called the "[[World's largest pharmacy (idiom)|world's largest pharmacy]]", because over one quarter of natural [[medicine]]s have been discovered within them.<ref>[http://www.animalcorner.co.uk/rainforests/rainforests.html Rainforests] {{webarchive|url=https://web.archive.org/web/20120708045901/http://www.animalcorner.co.uk/rainforests/rainforests.html |date=8 July 2012 }}. Animalcorner.co.uk (1 January 2004). Retrieved on 28 March 2013.</ref><ref>[https://web.archive.org/web/20130117075557/http://ngm.nationalgeographic.com/2013/02/venom/holland-text The bite that heals]. Ngm.nationalgeographic.com (25 February 2013). Retrieved on 24 June 2016.</ref> It is likely that there may be many millions of species of plants, insects and [[microorganism]]s 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.<ref name="SahneyBentonFerry2010LinksDiversityVertebrates">{{cite journal | author= Sahney, S., Benton, M.J. & Falcon-Lang, H.J. | year=2010 | title= Rainforest collapse triggered Pennsylvanian tetrapod diversification in Euramerica | journal=Geology | volume = 38 | pages = 1079–1082| doi=10.1130/G31182.1 | issue=12|bibcode = 2010Geo....38.1079S }}</ref> 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 [[Deforestation|agricultural clearance]] throughout the 20th century, and the area covered by rainforests around the world is rapidly shrinking.<ref>[https://www.theguardian.com/environment/2008/sep/01/forests.brazil Brazil: Deforestation rises sharply as farmers push into Amazon], The Guardian, 1 September 2008</ref><ref>[http://www.asianews.it/index.php?l=en&art=5728 China is black hole of Asia's deforestation], Asia News, 24 March 2008</ref>

=== History ===
[[File:Dipterocarp Forest at Danum Valley (13997709808).jpg|thumb|The [[Dipterocarpaceae|dipterocarp]] tree group has dominated the [[Borneo lowland rain forests]] for millions of years]]
Tropical rainforests have existed on earth for hundreds of millions of years. Most tropical rainforests today are on fragments of the [[Mesozoic|Mesozoic era]] supercontinent of [[Gondwana]].<ref name="CorlettandPrimack2006"/> The breakup of Gondwana 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.<ref name="CorlettandPrimack2006" /> However, the specifics of the origin of rainforests remain uncertain due to an incomplete fossil record.

=== Other types of tropical forest ===
{{Main|Tropical forest}}
Several biomes may appear similar to, or merge via [[ecotone]]s with, tropical rainforest:
[[File:Hana Highway Overlook.jpg|thumb|[[Hawaiian tropical rainforests|Hawaiian tropical rainforest]] seen from the [[Hana Highway]]]]
;Moist seasonal tropical forest:
[[File:Rain Forest Daintree Australia.jpg|thumb|[[Daintree rainforest]] in Queensland is a [[seasonal tropical forest]].]]
Moist [[seasonal tropical forest]]s receive high overall rainfall with a warm summer wet season and a cooler winter dry season. These forests usually fall under [[Tropical monsoon climate|tropical monsoon]] or [[Tropical savanna climate|tropical savanna]] climates. 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 forest]]s at higher elevations. Depending on latitude, the lower limit of montane rainforests on large mountains is generally between 1500 and 2500{{nbs}}m while the upper limit is usually from 2400 to 3300{{nbs}}m.<ref name=Bruijnzeel/>

;Flooded rainforests:
Tropical [[freshwater swamp forests]], or "flooded forests", are found in Amazon basin (the [[Várzea forest|Várzea]]) and elsewhere.