The impending destruction of South East Asia’s tropical rainforests will impact one of the most biodiverse areas in the world, an area which remains poorly understood due its biological, geographical, cultural, and economic features. The Malay Archipelago has the third largest tract of tropical rainforest in the world, spread over 17,500 islands (Simantujak et al.,1997). However, this has decreased by over 50% to 94 million hectares in 2010. This unique geographical situation results in high endemism but easily accessible forests for deforestation, with the result that some of the world’s most iconic species are facing deforestation rates eclipsing all other countries. 


Tropical Rainforests are the single most biodiverse habitat in the world and require very specific climatic conditions to exist. They are characterised by being both hot and wet with mean monthly temperatures over 18 degrees Celsius (Woodward, 2008), and rainfall between 1.7m and 10m annually (Newman, 2002). The high rates of evapotranspiration produce 75% of the precipitation rainforests receive. The extremely high volume of rainfall annually causes significant mineral leaching hence the habitat is typified by poor soils, so plants have adapted to grow large buttress root systems which are shallow to absorb nutrients from the leaf litter. Microorganisms quickly decompose the leaf litter, recycling the nutrients, most of which is then re-absorbed by the vegetation. Most modern fragments of rainforest are remnants from the supercontinent Gondwana, from the Mesozoic Era between 252 mya and 66 mya (Corlett and Primack, 2006). The fragmentation of landmasses resulted in a loss in amphibian diversity and the drier climate drove reptile diversification (Sahney, 2010). Tropical Rainforests are also Earth’s oldest ecosystems, with some having existed continuously for 70 million years, allowing diverse and continuous speciation.  


Tropical Rainforests are home to over 50% of all biotic species (Butler, 2019), and half of all animal and plant species, yet cover less than 6% of the earth’s surface. This high biodiversity and high density of species leads to high interspecific competition over ecological niches and can lead to niche partitioning. Indonesia goes further than this, due to its insular and mountainous geography leading to 36% of its 1,531 species of bird and 39% of its 515 species of mammal being endemic (Lambertini, 2000). In comparison, Brazil has 1,622 bird species of which just 12% are endemic, being a third of the proportion of endemic species richness found in Indonesia (Lambertini, 2000). Furthermore, the extreme diversity of Indonesia’s species also is a result of the fact that it sits at the conjunction of the boundary between two major zoogeographical regions, between the Australasian and oriental regions, which Alfred Russell Wallace identified as being at its most striking between the islands of Lombok and Bali, a mere 22 miles apart. As Wallace observes in his book ‘The Malay Archipelago’, in Bali you have represented, the avian families Megalaimidae,Turdidae, and Picidae which are typical oriental families, whilst in Lombok you have CacatuidaeMeliphagidae, and Megapodiidaetypical Australasian families. 

New Guinea reflects this, no more clearly seen than in Lorentz National Park, which is South East Asia’s largest national park, and the world’s only one that has a full range of ecosystems from Mangroves through to Alpine tundra. The national park contains 500 species of cockatoos (Cacatuidae), of which Australasia is typified. The mammalian species in the archipelago also reflect Wallace’s Line, with Java and Borneo having monkeys, civets, deer and otters, whilst other islands such as the Moluccas having just the Cuscus as the only terrestrial mammal excluding introduced species such as wild pigs and deer. Sumatra is unique in that it is the only place in the world where Elephants, Rhinoceros, Tigers and Orangutans co-exist. Perhaps the most poignant of the extreme biodiversity of the area are the Birds of Paradise which evolved from Corvidae around 30 mya. The islands, mountain ranges and volcanoes have produced the extreme diversity in niche and physical appearance we see today in the 42 species (Gill, 2012), which are among the most endangered and spectacular bird species in the world. Indonesia also sits within the Coral Triangle and has the highest number of coral species in the world – 1650 (Tamindiel, 2011) and hence the most biodiverse coral reefs in the world. Tropical Rainforests also host a spectacular anthropogenic culture with Indonesia tribes being famed for their colourful traditions and extensive knowledge of the area. Indonesia has the second highest number of uncontacted tribes after Brazil with most of them, 44 being in Irian Jaya, New Guinea (BBC, 2007) 


However South East Asia’s Rainforests are facing the highest relative levels of habitat destruction and fragmentation of all major tropical areas worldwide (Achard et al. 2002; Mayaux et al. 2005), driven particularly by the rapid population growth and resultant demand for natural resources. The population was 273.5m in mid 2020; the fourth largest in the world. Indeed 75% of South East Asia’s original forest cover could be lost by 2100 if current deforestation rates continue (Achard et al. 2002). By 2012, deforestation stood at 840,000 hectares, which eclipsed deforestation in Brazil (UN, 2010), which is extraordinary considering Brazil is nearly four times the size. This trend has continued to make Indonesia the fastest deforesting country. Fires are often used to deforest, and they often become uncontrollable and burn surrounding old-growth forests and peatlands, both of which are significant carbon sinks. Hence Indonesia is the world’s third largest greenhouse gas emitter after China and the USA (Seeburg-Elverfeldt et al., 2009.) The major causes of deforestation are multinational pulp companies which deforest to create plantations, and loggers. Furthermore, the Transmigration Program created by the Dutch colonial government and continued by the Indonesian government which moves people from high density urban areas to rural areas has worsened the situation. Over 20 million transmigrants are thought to live in Indonesia, although official statistics are a state secret. Unfortunately, the insular nature of the nation makes it more easily accessible to both legal and illegal loggers. Recent studies estimate that up to 88% of Indonesia’s logging is in fact illegal (Greenpeace, 2003), and most of this is due to the rapidly growing palm oil market. 

 Indonesia is both the world largest producer and consumer of palm oil and produces nearly half of the world palm oil annually (McClanahan, 2013). These palm oil plantations are monocultures and support little to no biodiversity so both destroy the most biodiverse ecosystems which absorb carbon dioxide and replace them with a monoculture. Furthermore, the fires used to deforest produce vast quantities of particulates, and 2.5 tons of waste liquid is produced for every ton of palm oil produced (WWF). This and the fertilisers used pollutes freshwater systems. Additionally, the soil erosion caused by root system removal results in increased flooding and sedimentation in freshwater and saltwater systems, often destroying coral reefs. Moreover, the illegality of the industry in many cases results in significant human rights violations such as child and forced labour, and worker exploitation. Other significant causes of deforestation include mining, which is a particular problem in New Guinea, which has the world’s largest gold mine, the Grasberg mine that destroyed valuable equatorial alpine ecosystems as it is situated at 4270m. It produces 700,000 tonnes of waste a day which has covered 230 km2 of alluvial systems (Van Zyl et al., 2002). Pollution levels in the riverine systems downstream are 94 times higher than the maximum levels under Indonesian law, around 50km away from the mine (Perlez, 2005). 


Indonesia is one of the world’s most biodiverse countries, with the highest levels of endemism of species in many taxonomic classes. Some of the world’s most charismatic species call the tropical islands their home, and yet Indonesia has the highest level of deforestation in the world. However, there is hope. Lorentz National Park was established officially in 1997 and is among the most important and pristine national parks in the world, with the most unique ecosystems. Species are still being discovered for those intrepid scientists who can reach it. And the best part of it is that there have been as of this year no detectable threats to the national park. Yet it has no park guards, no park staff, and minimal funding. It is the indigenous tribes who are protecting the national park, who know it better than anyone. And they are doing exceptionally well.  


Achard., F., H.D Eva, H.J. Stibig, P. Mayaux, J. Gallago, T. Richards, and J.P Malingreau, 2002. Determination of the deforestation rates of the world’s humid tropical forests. Science 297: 999 – 1002. 

BBC, 2007: First contact with isolated tribes? <>, accessed 10/10/2020 

Butler, R.A., Why are rainforests so diverse? Mongabay, accessed 10/10/2020, <> 

Corlett, R.T. and Primack, R.B., 2006. Tropical rainforests and the need for cross-continental comparisons. Trends in Ecology & Evolution, 21(2), pp.104-110. 

Gill, F., 2012. IOC world bird names (v 2.11). http://www. worldbirdnames. org/

 Global Forest Resources Assessment 2010 – Trends in Extent of Forest 1990–2010 Food and Agriculture Organization of the United Nations, Media Centre, Accessed 5 March 2012 

Greenpeace, U.K., 2003. Partners in Crime: A Greenpeace Investigation of the links between the UK and Indonesia’s timber barons. Greenpeace UK, London

Lambertini, M., 2000. A Naturalist’s Guide to the Tropics. University of Chicago Press. 

Mayaux, P., P. Holmgren, F. Achard, H.D Eva, H.J. Stibig, and A. Branthomme, 2005. Tropical forest cover change and options for future monitoring. Philosophical transactions of the Royal Society B: Biological Sciences 360: 373 – 384. 

McClanahan, P., 2013. Can Indonesia increase palm oil output without destroying its forest? Environmentalists doubt the world’s biggest palm oil producer can implement ambitious plans without damaging woodland. The Guardian, September, 11

Newman, A., 2002. Tropical rainforest: our most valuable endangered habit with a blueprint for its survival into the third millennium (No. 577.34 N551t). Checkmark Books,. 

Perlez, J. and Bonner, R., 2005. Below a mountain of wealth, a river of waste. New York Times, 27

Sahney, S., Benton, M.J. and Falcon-Lang, H.J., 2010. Rainforest collapse triggered Carboniferous tetrapod diversification in Euramerica. Geology, 38(12), pp.1079-1082. 

Seeberg-Elverfeldt, C., Schwarze, S. and Zeller, M., 2009. Payments for environmental services–Carbon finance options for smallholders’ agroforestry in Indonesia. International Journal of the Commons, 3(1). 

Simanjuntak, G.M., Margono, S.S., Okamoto, M. and Ito, A., 1997. Taeniasis/cysticercosis in Indonesia as an emerging disease. Parasitology Today, 13(9), pp.321-323. 

Tamindiel, O., 2011. Coral reef destruction spells humanitarian disaster. Antara News 

Van Zyl, D., Sassoon, M., Digby, C., Fleury, A.M. and Kyeyune, S., 2002. Mining for the future. Appendix J. International Institute for Environment and Development, World Business Council for Sustainable Development, 68, p.31. 

Woodward, S., 2008. Tropical broadleaf Evergreen Forest: The rainforest. Retrieved on, pp.03-14. 

World Wildlife Fund, Palm Oil, accessed 10/10/2020 <> 

About the author

Cosmo Le Breton