Editing Borneo (section)

==Geography==
===Geology===
{{see also|Geological history of Borneo}}

[[File:Regional map of SE Asia with Borneo Highlighted.svg|thumb|upright 1.2|left|Location of Borneo in [[Maritime Southeast Asia]].]]
Borneo was formed through [[Mesozoic]] accretion of microcontinental fragments, [[ophiolite]] terranes and [[island arc]] crust onto a [[Paleozoic]] continental core. At the beginning of the [[Cenozoic]] Borneo formed a [[promontory]] of [[Sundaland]] which partly separated from Asian mainland by the [[Tectonics of the South China Sea|proto-South China Sea]].<ref name="Geology of Borneo">{{cite journal|url=https://gsm.org.my/products/702001-100637-PDF.pdf|title=The origin of the 'circular basins' of Sabah, Malaysia|author1=Allagu Balaguru|author2=Gary Nichols|author3=Robert Hall|journal=Bulletin of the Geological Society of Malaysia, Royal Holloway University of London|via=Geological Society of Malaysia|year=2003|access-date=24 May 2019|page=337|archive-url=https://web.archive.org/web/20190524033404/https://gsm.org.my/products/702001-100637-PDF.pdf|archive-date=24 May 2019|url-status=dead}}</ref> The oceanic part of the proto-South China Sea was [[subduction|subducted]] during the [[Paleogene]] period and a large [[accretionary complex]] formed along the northwestern of the island of Borneo. In the [[early Miocene]] uplift of the accretionary complex occurred as a result of underthrusting of thinned continental crust in northwest.<ref name="Geology of Borneo"/> The uplift may have also resulted from shortening due to the counter-clockwise rotation of Borneo between 20 and 10 [[mega-annum]] (Ma) as a consequence of [[Australia (continent)|Australia]]-Southeast Asia collision.<ref name="Geology of Borneo"/> Large volumes of [[sediment]] were shed into basins, which scattered offshore to the west, north and east of Borneo as well into a [[Neogene]] basin which is currently exposed in large areas of eastern and southern [[Sabah]]. In southeast Sabah, the [[Miocene]] to recent island arc terranes of the [[Sulu Archipelago]] extend onshore into Borneo with the older [[volcanic arc]] was the result of southeast dipping subduction while the younger volcanics are likely resulted from northwest dipping subduction the [[Celebes Sea]].<ref name="Geology of Borneo"/>

[[File:Jack fish and reef sharks.jpg|thumb|left|Marine life off the coast of Borneo, in the Sulu Sea]]

Before sea levels rose at the end of the [[Last Glacial Period|last ice age]], Borneo was part of the mainland of Asia, forming, with [[Java]] and [[Sumatra]], the upland regions of a peninsula that extended east from present day [[Indochina]]. The [[South China Sea]] and [[Gulf of Thailand]] now submerge the former low-lying areas of the peninsula. Deeper waters separating Borneo from neighbouring [[Sulawesi]] prevented a land connection to that island, creating the divide known as [[Wallace's Line]] between Asian and Australia-[[New Guinea]] biological regions.<ref>{{cite book|author=James Allan Taylor|title=Biogeography: Recent Advances and Future Directions|url=https://books.google.com/books?id=xz9dWjh_CAsC&pg=PA178|year=1984|publisher=Rowman & Littlefield|isbn=978-0-389-20507-4|pages=178–}}</ref><ref>{{cite web|url=http://www.starfish.ch/dive/Wallacea.html|title=Wallacea|author=Teresa Zubi|publisher=Starfish|date=25 October 2015|access-date=26 May 2017|archive-url=https://web.archive.org/web/20170525180130/http://www.starfish.ch/dive/Wallacea.html|archive-date=25 May 2017|url-status=dead}}</ref> The island today is surrounded by the [[South China Sea]] to the north and northwest, the [[Sulu Sea]] to the northeast, the Celebes Sea and the [[Makassar Strait]] to the east, and the [[Java Sea]] and [[Karimata Strait]] to the south. To the west of Borneo are the [[Malay Peninsula]] and [[Sumatra]]. To the south and east are islands of Indonesia: [[Java (island)|Java]] and [[Sulawesi]], respectively. To the northeast are the [[Philippines|Philippine Islands]]. With an area of {{convert|743330|km2|sqmi}}, it is the third-largest island in the world, and is the largest island of [[Asia]] (the largest continent). Its highest point is [[Mount Kinabalu]] in Sabah, Malaysia, with an elevation of {{convert|4095|m|ft|0|abbr=on}}.<ref name="highest summit"/>
[[File:Lahan basah Taman Nasional Danau Sentarum, Kalimantan Barat.jpg|thumb|[[Lake Sentarum National Park|Lake Sentarum]], Kapuas Hulu Regency, West Kalimantan]]
The largest river system is the [[Kapuas River|Kapuas]] in [[West Kalimantan]], with a length of {{convert|1143|km|mi|abbr=on}}.<ref name="TanMerdikawati2015"/> Other major rivers include the [[Mahakam River|Mahakam]] in [[East Kalimantan]] ({{convert|980|km|mi|abbr=on}} long),<ref>{{cite book|author=Tomas Tomascik|title=The Ecology of the Indonesian Seas|url=https://books.google.com/books?id=0Kc80Hd2HagC&pg=PP54|year=1997|publisher=Oxford University Press|isbn=978-0-19-850186-2|pages=54–}}</ref> the [[Barito River|Barito]], [[Kahayan River|Kahayan]], and [[Mendawai River|Mendawai]] in [[South Kalimantan]] ({{convert|1090|km|mi|abbr=on}}, {{convert|658|km|mi|abbr=on}}, and {{convert|616|km|mi|abbr=on}} long respectively),<ref>{{cite book|author1=Khee Giap Tan|author2=Mulya Amri|author3=Linda Low|author4=Kong Yam Tan|title=Competitiveness Analysis and Development Strategies for 33 Indonesian Provinces|url=https://books.google.com/books?id=Q526CgAAQBAJ&pg=PA338|year=2013|publisher=World Scientific|isbn=978-981-4504-86-7|pages=338–}}</ref> [[Rajang River|Rajang]] in Sarawak ({{convert|565|km|mi|abbr=on}} long)<ref>{{cite book|title=Tropical River Fisheries Valuation: Background Papers to a Global Synthesis|url=https://books.google.com/books?id=mmrmRVVSiIYC&pg=PT218|year=2008|publisher=WorldFish|isbn=978-983-2346-61-6|pages=218–}}</ref> and [[Kinabatangan River|Kinabatangan]] in Sabah ({{convert|560|km|mi|abbr=on}} long).<ref>{{cite book|author1=Uwe Tietze|author2=Food and Agriculture Organization of the United Nations|title=Credit and Microfinance Needs in Inland Capture Fisheries Development and Conservation in Asia|url=https://books.google.com/books?id=ihTrWUKDvLUC&pg=PA131|year=2007|publisher=Food & Agriculture Org.|isbn=978-92-5-105756-8|pages=131–}}</ref> Borneo has significant cave systems. In Sarawak, the Clearwater Cave has one of the world's longest underground rivers while [[Deer Cave]] is home to over three million [[bat]]s, with [[guano]] accumulated to over {{convert|100|m}} deep.<ref>{{cite web|url=http://www.sarawak.gov.my/ebook/Sarawak_Tourism/Visitor_Guide/files/basic-html/page100.html|title=Sarawak Visitors Guide|publisher=Sarawak State Government|access-date=26 May 2017|page=100}}</ref> The [[Gomantong Caves]] in Sabah has been dubbed as the "Cockroach Cave" due to the presence of millions of cockroaches inside the cave.<ref>{{cite web|url=http://voices.nationalgeographic.com/2015/10/29/billions-of-bugs-feast-on-flesh-and-dung-in-borneo/|archive-url=https://web.archive.org/web/20151030152107/http://voices.nationalgeographic.com/2015/10/29/billions-of-bugs-feast-on-flesh-and-dung-in-borneo/|url-status=dead|archive-date=30 October 2015|title=WATCH: Billions of Bugs Feast on Flesh and Dung in Borneo|author=Nora Rappaport|publisher=[[National Geographic Society|National Geographic]]|date=29 October 2015|access-date=26 May 2017}}</ref><ref>{{cite web|url=http://www.ibtimes.co.uk/cockroach-cave-where-billions-bugs-feed-dead-animals-dung-video-1526507|title=Cockroach cave: Where billions of bugs feed on dead animals and dung [Video]|author=Sean Martin|publisher=International Business Times (UK)|date=31 October 2015|access-date=26 May 2017}}</ref> The [[Gunung Mulu National Park]] in Sarawak and [[Sangkulirang-Mangkalihat Karst]] in East Kalimantan which particularly a [[karst]] areas contains thousands of smaller caves.<ref>{{cite book|author1=Quentin Phillipps|author2=Karen Phillipps|title=Phillipps' Field Guide to the Mammals of Borneo and Their Ecology: Sabah, Sarawak, Brunei, and Kalimantan|url=https://books.google.com/books?id=0SxzCwAAQBAJ&pg=PA31|date=10 May 2016|publisher=Princeton University Press|isbn=978-0-691-16941-5|pages=31–}}</ref>

===Ecology===
{{see also|Biodiversity of Borneo|Fauna of Borneo|Flora of Borneo|List of endemic birds of Borneo|List of mammals of Borneo}}
[[File:Bornean orangutan (Pongo pygmaeus), Tanjung Putting National Park 01.jpg|thumb|left|The [[critically endangered]] [[Bornean orangutan]], a great ape [[endemic]] to Borneo]]

The Borneo [[rainforest]] is estimated to be around 140 million years old, making it one of the oldest rainforests in the world.<ref>{{cite book|author1=Andy Leeder|author2=Alan Brown|author3=Gregg Coleman|author4=Bob Digby|author5=Glyn Owen|author6=Val Davis|title=WJEC GCSE Geography|url=https://books.google.com/books?id=rDjEDAAAQBAJ&pg=PA199-IA444|date=22 August 2016|publisher=Hodder Education|isbn=978-1-4718-6130-7|pages=199–}}</ref> The current dominant tree group, the [[Dipterocarpaceae|dipterocarps]], has dominated the [[Borneo lowland rain forests]] for millions of years.<ref>{{cite news |title=A prehistoric forest grows in Brunei |url=https://www.sciencedaily.com/releases/2022/04/220428104015.htm |work=ScienceDaily |date=28 April 2022}}</ref> It is the centre of the evolution and distribution of many [[Endemism|endemic]] species of plants and animals, and the rainforest is one of the few remaining [[Habitat (ecology)|natural habitats]] for the endangered [[Bornean orangutan]]. It is an important refuge for many endemic forest species, including the [[Borneo elephant]], the [[eastern Sumatran rhinoceros]], the [[Bornean clouded leopard]], the [[Staurois tuberilinguis|Bornean rock frog]], the [[hose's palm civet]] and the [[dayak fruit bat]].<ref>{{cite web|url=http://wwf.panda.org/index.cfm?uNewsID=89620|title=Scientists find dozens of new species in Borneo rainforests|publisher=[[World Wide Fund for Nature]]|date=19 December 2006|access-date=26 May 2017}}</ref><ref>{{cite web|url=http://wwf.panda.org/what_we_do/where_we_work/borneo_forests/about_borneo_forests/borneo_animals/|title=Borneo wildlife|publisher=World Wide Fund for Nature|access-date=26 May 2017}}</ref>

[[File:Borneo 19 May 2002.jpg|thumb|[[NASA]] satellite image of Borneo on 19 May 2002]]

[[Borneo peat swamp forests|Peat swamp forests]] occupy the entire coastline of Borneo.<ref>{{cite book|author1=Kathy MacKinnon|author2=Gusti Hatta|title=Ecology of Kalimantan: Indonesian Borneo|url=https://books.google.com/books?id=FFXRAgAAQBAJ&pg=PT148|date=5 February 2013|publisher=Tuttle Publishing|isbn=978-1-4629-0505-8|pages=148–}}</ref> The soil of the peat swamp is comparatively infertile, while it is known to be the home of various bird species such as the [[hook-billed bulbul]], [[helmeted hornbill]] and [[rhinoceros hornbill]].<ref name=birds /> There are about 15,000 species of [[flowering plant]]s with 3,000 species of trees (267 species are [[dipterocarp]]s), 221 species of terrestrial mammals and 420 species of resident birds in Borneo.<ref>{{cite book|last=MacKinnon, K|title=The Ecology of Kalimantan|year=1998|publisher=[[Oxford University Press]]|location=London|display-authors=etal}}</ref> There are about 440 freshwater fish species in Borneo (about the same as Sumatra and Java combined).<ref>Nguyen, T.T.T., and S. S. De Silva (2006). "Freshwater Finfish Biodiversity and Conservation: An Asian Perspective", ''Biodiversity & Conservation'' 15(11): 3543–3568</ref> The [[Glyphis fowlerae|Borneo river shark]] is known only from the [[Kinabatangan River]].<ref>{{cite journal |last1=Li |first1=C. |last2=Corrigan |first2=S. |last3=Yang |first3=L. |last4=Straube |first4=N. |last5=Harris |first5=M. |last6=Hofreiter |first6=M. |last7=White |first7=W.T. |last8=Naylor |first8=G.J.P. |title=DNA capture reveals transoceanic gene flow in endangered river sharks |journal=Proceedings of the National Academy of Sciences |year=2015 |volume=112 |issue=43 |pages=13302–13307|doi=10.1073/pnas.1508735112 |pmid=26460025 |pmc=4629339|bibcode=2015PNAS..11213302L |doi-access=free }}</ref> In 2010, the [[World Wide Fund for Nature]] (WWF) stated that 123 species have been discovered in Borneo since the "[[Heart of Borneo]]" agreement was signed in 2007.<ref>{{cite web|url=https://www.wwf.org.uk/updates/scientists-discover-new-species-heart-borneo|title=Scientists discover new species in Heart of Borneo|publisher=World Wide Fund for Nature|date=22 April 2010|access-date=26 May 2017|archive-url=https://web.archive.org/web/20200228162702/https://www.wwf.org.uk/updates/scientists-discover-new-species-heart-borneo|archive-date=28 February 2020|url-status=dead}}</ref>

[[File:Logging road East Kalimantan 2005.jpg|thumb|right|Logging road in [[East Kalimantan]], Indonesia]]

The WWF has classified the island into seven distinct [[ecoregion]]s. Most are lowland regions:<ref name="Borneo forests">{{cite web|url=http://wwf.panda.org/about_our_earth/ecoregions/borneo_lowland_forests.cfm|title=Borneo Lowland & Montane Forests – A Global Ecoregion|publisher=World Wide Fund for Nature|access-date=26 May 2017|url-status=dead|archive-url=https://web.archive.org/web/20170715021114/http://wwf.panda.org/about_our_earth/ecoregions/borneo_lowland_forests.cfm|archive-date=15 July 2017}}</ref><ref>{{cite web|url=https://www.worldwildlife.org/ecoregions/im0104|title=Southeastern Asia: Indonesia, Malaysia, and Brunei|author=Colby Loucks|publisher=World Wide Fund for Nature|access-date=26 May 2017}}</ref><ref>{{cite web|url=https://www.worldwildlife.org/ecoregions/im0161|title=Sundaland heath forests|publisher=World Wide Fund for Nature|access-date=26 May 2017}}</ref>
* [[Borneo lowland rain forests]] cover most of the island, with an area of {{convert|427500|km2}}.
* [[Borneo peat swamp forests]]
* ''[[Kerangas]]'' or Sundaland heath forests
* [[Southwest Borneo freshwater swamp forests]] are found in the island's western and southern lowlands
* [[Sunda Shelf mangroves]]
* The [[Borneo montane rain forests]] lie in the central highlands of the island, above the {{convert|1000|m}} elevation.
*The highest elevations of [[Mount Kinabalu]] are home to the [[Kinabalu montane alpine meadows]], a subalpine and alpine shrubland notable for its numerous endemic species, including many orchids.

According to analysis of data from [[Global Forest Watch]],<ref>{{cite web|url=https://www.globalforestwatch.org|title=Global Forest Watch|publisher=World Resources Institute|access-date=14 August 2020}}</ref> the Indonesian portion of Borneo lost {{convert|10.7|e6ha|abbr=off}} of tree cover between 2002 and 2019, of which {{convert|4|e6ha|abbr=off}} was [[primary forest]], compared with Malaysian Borneo's {{convert|4.4|e6ha|abbr=off}} of tree cover loss and {{convert|1.9|e6ha|abbr=off}} of primary forest cover loss. As of 2020, Indonesian Borneo accounts for 72% of the island's tree cover, Malaysian Borneo 27%, and Brunei 1%. Primary forest in Indonesia accounts for 44% of Borneo's overall tree cover.<ref>{{cite web|url=https://rainforests.mongabay.com/borneo/|title=Borneo|publisher=Mongabay.com|access-date=14 August 2020}}</ref>

====Conservation issues====
{{see also|Deforestation in Borneo|1997 Indonesian forest fires|1997 Southeast Asian haze|2006 Southeast Asian haze|2013 Southeast Asian haze|2015 Southeast Asian haze|2016 Southeast Asian haze|2019 Southeast Asian haze}}
[[File:Logging in Borneo (3540116932).jpg|thumb|Logging near [[Crocker Range National Park]]. Borneo has lost more than half of its rainforests in the past half century.<ref>{{cite news |title=What Causes Deforestation in Borneo and How Do We Stop It? |url=https://earth.org/deforestation-in-borneo/ |work=Earth.org |date=2 March 2023}}</ref>]]

The island historically had extensive rainforest cover, but the area was reduced due to heavy [[logging]] by the [[Indonesia|Indonesian]] and [[Malaysia|Malaysian]] [[wood industry]], especially with the large demands of raw materials from [[developed country|industrial countries]] along with the conversion of forest lands for large-scale agricultural purposes.<ref name="Borneo forests"/> Half of the annual global [[tropical timber]] acquisition comes from Borneo. [[Palm oil]] plantations have been widely developed and are rapidly encroaching on the last remnants of primary rainforest.<ref>{{cite web|url=http://wwf.panda.org/what_we_do/where_we_work/borneo_forests/borneo_deforestation/|title=Threats to Borneo forests|publisher=World Wide Fund for Nature|access-date=26 May 2017|url-status=dead|archive-url=https://web.archive.org/web/20160525051215/http://wwf.panda.org/what_we_do/where_we_work/borneo_forests/borneo_deforestation/|archive-date=25 May 2016}}</ref> [[Wildfire|Forest fires]] since [[1997]], started by the locals to clear the forests for plantations were exacerbated by an exceptionally dry [[El Niño]] season, worsening the annual shrinkage of the rainforest.<ref>{{cite news|url=http://www.latimes.com/world/asia/la-fg-great-haze-explainer-20151021-htmlstory.html|title=Fires in Southeast Asia may be emitting more greenhouse gases than the entire U.S.|author=Jonathan Kaiman|newspaper=[[Los Angeles Times]]|date=21 October 2015|access-date=27 May 2017}}</ref> During these fires, hotspots were visible on [[Satellite imagery|satellite images]] and the resulting [[haze]] frequently affected [[Brunei]], [[Indonesia]] and [[Malaysia]]. The haze could also reach southern [[Thailand]], [[Cambodia]], [[Vietnam]] and the [[Philippines]] as evidenced on the [[2015 Southeast Asian haze]].<ref>{{cite web|url=http://www.eria.org/ERIA-DP-2015-82.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.eria.org/ERIA-DP-2015-82.pdf |archive-date=9 October 2022 |url-status=live|title=Transboundary Haze Pollution Problem in Southeast Asia: Reframing ASEAN's Response|author=Apichal Sunchindah|publisher=Economic Research Institute for ASEAN and East Asia|date=December 2015|access-date=27 May 2017}}</ref>

A study in [[2018]] found that [[Bornean orangutan]]s declined by 148,500 individuals from [[1999]] to [[2015]].<ref>{{cite news |last1=Solly |first1=Meilan |title=Borneo's Orangutan Population Plummeted by Half in 16 Years |url=https://www.smithsonianmag.com/smart-news/borneos-orangutan-population-plummeted-half-16-years-180968189/ |work=[[Smithsonian (magazine)|Smithsonian]] |date=16 February 2018}}</ref>

===Topography===
[[File:MountKinabalu from CheSuiKhorPagodaKK-01.jpg|thumb|[[Mount Kinabalu]] in Malaysia, the highest summit of the island<ref name="highest summit">{{cite web|url=https://www.pbs.org/edens/borneo/awesome.html|title=An Awesome Island|work=Borneo: Island in the Clouds|publisher=PBS|access-date=11 November 2012}}</ref>]]

List of highest peaks in Borneo by elevation:

* [[Mount Kinabalu]] {{convert|13,435|ft|m|abbr=on}}
* [[Mount Trusmadi]] {{convert|8,668|ft|abbr=on}}
* [[:id:Bukit Raya|Raya Hill]] {{convert|7,474|ft|abbr=on}}
* Muruk Miau {{convert|6,837|ft|abbr=on}}
* Mount Wakid {{convert|6,778|ft|abbr=on}}
* Monkobo Hill {{convert|5,866|ft|abbr=on}}
* Mount Lotung {{convert|5,843|ft|abbr=on}}
* [[Mount Magdalena]] {{convert|4,288|ft|abbr=on}}
* Talibu Hill {{convert|4,144|ft|abbr=on}}

===River systems===
[[File:Scenery around Kapuas River.jpg|thumb|right|[[Kapuas River]] in Indonesia. At {{convert|1000|km|mi|abbr=on}} in length, it is the longest river in Borneo.<ref name="TanMerdikawati2015">{{cite book|author1=Khee Giap Tan|author2=Nurina Merdikawati|author3=Mulya Amri|author4=Blake Harley Berger|title=2014 Annual Competitiveness Analysis and Development Strategies for Indonesian Provinces|url=https://books.google.com/books?id=G1gGCwAAQBAJ&pg=PA286|date=8 September 2015|publisher=World Scientific|isbn=978-981-4730-43-3|pages=286–}}</ref>]]

List of rivers in Borneo by length:

* [[Kapuas River]] {{convert|1,143|km|abbr=on}}
* [[Barito River]] {{cvt|1,090|km|abbr=on}}
* [[Mahakam River]] {{convert|980|km|abbr=on}} 
* [[Kahayan River]] {{cvt|658|km|abbr=on}}
* [[Mendawai River]] {{convert|616|km|abbr=on}}
* [[Kayan River]] {{convert|576|km|abbr=on}}
* [[Rajang River]] {{convert|565|km|mi|abbr=on}}
* [[Kinabatangan River]] {{convert|560|km|abbr=on}}
* [[Baram River]] {{convert|400|km|abbr=on}}
* [[Sembakung River]] {{convert|352|km|abbr=on}}
* [[Sesayap River]] {{convert|279|km|abbr=on}}
* [[Pawan River]] {{convert|197|km|abbr=on}}