Surrounded by the South China Sea to the north and northwest, the Sulu Sea to the north east, the Celebes Sea and the Makassar Strait to the east, and the Java Sea and Karimata Strait to the south, Borneo is, at 743,330 Km2, the world’s third largest island, and lies to the east of Sumatra. Borneo is divided between three countries; the state of Brunei-Darussalam, the Malaysian states of Sarawak and Sabah, and the Indonesian territory of Kalimantan, and has a human population of around 16,000,000 , with the majority of settlements and cities lying near to, or along, the coastline or Borneo’s extensive river system (Smith, 2007).


borneoforestcovermongabayLike Sumatra, Borneo is extraordinarily rich in biodiversity. The major forest type throughout the island is evergreen lowland diptercarp rainforest, with hill diptercarp, mangrove, fresh water, peat swamp, ironwood, heathland and montane forests all also found (Rautner at al, 2005), and harbouring 3,000 species of trees, 15,000 species of flowering plants, 221 species of terrestrial mammals, including 13 species of primate, and 420 species of birds (Mackinnon et al, 1997). However, also like Sumatra, widespread logging, which began under the period of European colonization and has accelerated in the last 40 years, and the growing palm oil industry and related forest conversion, has seen the islands forest cover decrease by around 50% (Matthews, 2002). It is now estimated that the area under concession for logging and oil palm cultivation in Borneo is larger than that of the remaining forest (Rijsken & Meijaard, 1999).


The most recent estimates put the population of Bornean orangutans at around 55,000 (Wich et al, 2008), and the species, better known and generally better studied than its Sumatran cousin, has benefited from both a strong international NGO presence, and Borneo’s series of national parks, which, despite massive incursions and continued threats, today harbor significant populations of orangutans.  In 2016, the IUCN reclassified the Bornean orangutan as "critically endangered" primarily due to the continued degradation of habitat (IUCN Redlist, 2016)


tanjungputingdeforestationmongabayKalimantan is divided in to four provinces, Central, West, East and South. The two national parks with the largest orangutan populations are found in Central Kalimantan. The most famous, Tanjung Puting, is a 400,000 hectare park renowned for its long term wild orangutan study and rehabilitation program. Despite its high profile and strong NGO presence, the park has been subjected to widespread illegal logging, conversion, for both palm oil production and agriculture, forest fires and illegal gold mining, and studies conducted in 2009 showed that just 66% of the park remains under some kind of forest cover (Infinite Earth, 2009). If current plans by the local government to decrease the size of the park by 25% take place, thousands of orangutans will be lost. Sebangau National Park was created as a national park in 2004 and covers an area of 568,700 hectares. Like Tanjung Puting, the park has been subjected to incursions, and historic draining of the parks’ peat swamps, to aid the extraction of logs from the forest, has left it prone to almost annual fires. Despite this, the two parks have a combined orangutan population of around 12,000 orangutans (Singleton et al, 2004).

An ambitious, multi-stakeholder and multi-national plan to conserve 91,000 hectares on the border of Tanjung Puting National Park was, in September 2011, in the final stages of development, and would have formed Indonesia’s first REDD reserve, whereby outside investors agree to fund conservation of carbon rich peat forests in return for offsetting their own carbon emissions. However, despite international support and hopes that the project would act as an example to other such efforts, at the last minute, the national government decided to cut the size of the reserve, known as Rimba Raya, in half, handing one side to a palm oil company. Since then, conservatinists have tried hard to convince the government of the project's worth, and in December 2012, their efforts seemed to have paid off; the government announced 80,000 hectares would be set aside as a reserve. Although the implementation of such a project, the first of its kind in Indonesia, remains challenging, and many remain convinced its goals are unrealisic, it is hoped that over a 30 year period, the reserve will generate between $390 to 650 million worth of carbon offset credits, providing a financial incentive for local people, businesses and governments to protect the reserve.


gunungpalungdeforestationusccspGunung Palung National Park is a 90,000 hectare park in West Kalimantan known for its high biodiversity and mixture of habitat types. Despite being the site of a long term wild orangutan study, having a strong international NGO presence and being one of the provinces most popular tourist destinations, the park has been heavily logged, and its 2500 wild orangutans are under constant threat.  In November 2011, illegal logging in the park was so bad it had reached the study area of a well-known long term scientific research project, and all scientific researchers were told to leave the park. Two other national parks in West Kalimantan, Danau Sentarum and Betung Kerihun , have also suffered from logging, and studies indicate that the former contains an orangutan population of just 500 individuals (Singleton et al, 2004), and the latter has suffered from widespread poaching, with an unknown population (WWF, 2010). Although NGO presence and conservation initiatives in these parks are increasing, efforts are hampered by the fact that large numbers of orangutans occur in legally unprotected forests outside the park borders.


Kutai National Park in East Kalimantan was once one of the most pristine and bio-diverse parks in Indonesia, but in the last few decades, the park has been invaded by logging concessions, industrial complexes, open pit coalmines and settlements, ravaged by forest fires, and it is likely that just 10% of the park remains forested, with an orangutan population of just 500 (Singleton et al, 2004). Media reports in 2009 suggested the population could be even lower, and reported that the park now contains an airport, gas stations and even a prostitution complex (Mongabay, 2009).  A new project set up by the University of Toronto has found that, despite these threats, orangutans are living in parts of the park in high densities, and that habitat is recovering well from damage. Although the project is in its early stages, increased conservation efforts should hopefully bring increased awareness to this area.


As national parks throughout the island continue to struggle against the onslaught of huge palm oil expansion and logging, attention is being increasingly focused on the areas of forest outside of the national park system. In Central Kalimantan, conservationists are working to protect the 76,000 hectare Lamandau Nature Reserve, an expired logging concession comprised mainly of peat swamp, which acts as an rehabilitated orangutan release site, and the Belantikan Hulu region, which is home to an estimated 6,000 orangutans, the largest population outside of a protected area. NGO’s have also been working to protect the 377,000 hectare Mawas Reserve, home to 3,500 orangutans, in Central Kalimantan, and an ambitious plan by WWF to conserve 22 million hectares of land, an area that encompasses protected areas, reserves, sustainably managed buffer zones and wildlife corridors, called the ‘Heart of Borneo’, would, if successful, protect thousands of orangutans in the centre of the island. The publicity surrounding this scheme seems to have thwarted a plan by the Indonesian and Malaysian governments to establish the world’s largest palm oil plantation in this area, but the threat remains ever present.


lowerkinabatanganworldlandtrustLike Kalimantan, the orangutans in the Malaysian states of Sarawak and Sabah have long faced rapidly decreasing forests, and the spread of palm oil plantations has forced remaining orangutans in to small, isolated populations in heavily degraded forests. Sabah contains a population of just 11,000 orangutans, and around 60% of this number are living outside of protected areas, in secondary forests often exploited by indigenous communities and forest industries (Ancrenaz at al, 2007). In depth studies in the Kinabatangan flood plain, which harbors 1,100 orangutans, has shown that they can survive in high numbers in degraded secondary forest (Ancrenaz et al, 2007), and the formation of the Lower Kinabatangan Wildlife Sanctuary in this area is a promising step for the survival of orangutans in Sabah.


The Batang Ai National Park, a 24,281 hectare tropical rainforest, and the nearby Lanjak Entimau Wildlife Sanctuary are two of the last strongholds of the orangutan in Sarawak, with a combined population of around 1,500 (Singleton et al, 2004). Although these parks are generally well protected, hunting and illegal logging remains a problem in this area (Caldecott & McConkey, 2006), and the threat of these forests being converted in future to facilitate palm oil expansion remains strong.


The threats facing the forests of Kalimantan, Sabah and Sarawak, and the animals and people who depend on them, have never been greater. However, with continued environmental awareness, growing prosperity in both Malaysia and Indonesia and international pressure, it is hoped the future of these great forests can be ensured.




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Caldecott, J. & McConkey, K. R, (2006). Orangutan Overview. In J. Caldecott and L. Miles, editors. World Atlas of Great Apes and their Conservation. UNEP-WCMC and University of California Press, London

Mongabay (2009). Orangutan population in Borneo park plunges 90% in 5 years.

Rautner, M., Hardiono, M. & Alfred, R.J. (2002). Borneo: Treasure island at risk. WWF

Rijksen H. & Meijaard E. (1999). Our vanishing relative. The status of wild orangutans at the turn of the 20th century. Kluwer academic Publishers, Netherlands.

Singleton, I., Wich, S., Husson, S., Stephens, S., Utami Atmoko, S., Leighton, M., Rosen, N., Traylor-Holzer, K., Lacy, R. & Byers, O. (2004). Orangutan population and habitat viability assessment: Final report. IUCN/SSC Conservation Breeding Specialist Group, Apple Valley, MN

Smith D.A. (2007). The conservation status of the primates of Borneo. Oxford Brookes University MSc Dissertation

Wich S.A., Maijaard, E., Marshall, A.J., Husson, S., Ancrenaz, M., Lacy, R.C., Van Schaik, C.P., Sugardjito, J., Simorangkir, T., Traylor-Holzer, K., Doughty, M., Supriatna, J., Dennis, R., Gumal, M., Knott, C.D. & Singleton, I. (2008). Distribution and conservation status of the orangutan on Borneo and Sumatra. How many remain?. Oryx, vol 42, issue 3, pp. 329-339

WWF (2010). Borneo. WWF