"Where on earth is Sundaland?" I hear you ask, since it isn't usually shown on the map. Sundaland encompasses many of Indonesia’s large tropical islands such as Borneo, Sumatra, Java and Bali as well as the western part of Malaysia, Brunei and the southern tip of Thailand, all of which lie on the Sunda Plate.
Before the last Ice Age
around 26,000 to 19,000 years ago,
plants and animals could move freely between Indo -Burma and Sundaland which is why they share some common ancestors. However, once the ice
melted and sea levels rose - around 8,000 and 6,000 years ago, they could no
longer do so, resulting in the high degree of endemicity as the now trapped
species evolved in isolation from one another.
Sundaland
ought to be called Wonderland for its astonishing array of plants and animals. Despite only occupying 4% of the world's land
area, it contains 25% of its biodiversity. It has more than 25,000 plant
species, almost twice as
many as Indo -Burma and 15,000 found nowhere else.
It also has 380 types of mammals, 170 of which are endemic, including the critically endangered Bornean and Javan Orangutans, the Bornean Bearded Pig and its very own Sun Bear, although a larger species common to Sundaland and Indo Burma, also exists.
Sundaland’s wet forests also support 450 species of reptiles 250 of which are endemic and 240 amphibians of which 200 only exist here. Below are just a few. Note also how endangered many of them are.
🌿 Iconic Species of Sundaland
Click on any name to learn more
- Bornean Orangutan (Pongo pygmaeus) – Critically Endangered – Borneo
- Sumatran Orangutan (Pongo abelii) – Critically Endangered – Sumatra
- Javan Rhino (Rhinoceros sondaicus) – Critically Endangered – Java
- Sumatran Rhino (Dicerorhinus sumatrensis) – Critically Endangered – Sumatra, Borneo
- Proboscis Monkey – Endangered – Borneo
- Bali Myna – Critically Endangered – Bali
- Rafflesia arnoldii – Largest flower on Earth – Sumatra, Borneo
- Dipterocarps – Keystone tree family – Lowland forests across Sundaland
Meet Some Forest Dwellers
Orangutans
Orangutans are often called 'gardeners of the forest' because they play a crucial role in seed dispersal since they
are known to consume more than 500 types of plants. Sadly, Bornean Orangutans have
declined by more than 50% in the last 60 years and their habitat has declined
by 55% in the last 20 years, so that some subspecies are now on the critically
endangered list.
Groups such as the World Wildlife Fund are working hard to
restore habitat and retain corridors even in timber concessions and palm
plantations, reducing human and orangutan conflict by locating agricultural
activities further from orangutan forests and helping groups such as TRAFFIC,
local authorities and customs in destination ports to crack down on the illegal
wildlife trade.
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| Bornean Orangutan |
© Photo: | | Source: Wikimedia Commons
Sun Bears
A Sun Bear Conservation Centre has now been established at Sabah in Malaysian Borneo to rehabilitate those which have been orphaned, injured or been kept captive with a view to returning them to the wild. It also conducts research and seeks to educate the public both locally and internationally.
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| Bornean Sun Bear |
© Photo: | | Source: Flickr
Meet the Plants
Dipterocarps (Dipterocarpae) are tall, broad leafed trees with winged seeds and there are around 695 species scatttered around the world. Borneo and the Malay Peninsula have the greatest diversity of such trees with Borneo alone having 155 endemic species. Some may be as much as 1000 years old.
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| Dipterocarp and its Winged Seeds |
© Photo: | | Source: Flickr
Almost as tall as a California Redwood and a prized hardwood, they are extensively exploited. They dominate the rainforest canopy, providing food and shelter for countless species including orangutans and also create a microclimate which supports many exotic plants. Lowland dipterocarp forests of Sumatra and the Malay Peninsula each host dozens of rare orchids as well as the world’s largest flower – the one metre wide Rafflesia arnoldii.
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| Raffelesia arnoldii |
The Rafflesia is also known as ‘the stinking corpse lily,’ because of its pungent smell, but it isn't the only forest flower in Sundaland with that reputation. There is another flower -the Titan Arum Lily found in Sumatra which is known as 'the rotting flesh lily.' Fortunately both prefer insects rather than humans though I can see where 1960s SciFi movies such as the "Day of the Triffids"or the "The Little Shop of Horrors" could have gotten their inspiration.
The Titan Arum Lily has no petals and is also around one metre across and can be up to three metres high. It only flowers every 7-10 years. Unlike Rafflesia, the Titan Arum Lily can be cultivated outside its home range, so they have found their way into several Botanic Gardens around the world. There is great excitement when one is about to bloom.
When one began to open at the Geelong Botanic Gardens in regional Australia recently, it attracted 20,000 visitors and a global livestream audience of 350,000. A further 32 million people followed the proceedings on global media. After all that anticipation, the flower only lasts 24 -48 hours, but such are the wonders which you might encounter in Sundaland.
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| Captive Titan Arum Lily |
© Photo: | | Source: Flickr
Why Islands are Especially Vulnerable
- High endemism: Islands like Java, Sumatra, and Borneo host species found nowhere else. Once their habitat is gone, extinction is often irreversible. As it stands the Javan Rhino is confined to only one park and the habitat for Sumatran Tigers and Sumatran Orangutans is shrinking, made worse by peat fires which release vast quantities of CO2. Endemic birds such as the Javan Hawk Eagle are declining.
- Limited dispersal: Species can’t easily migrate to new habitats when forests are fragmented or cleared — especially true for flightless birds, amphibians, and forest-dependent mammals. The Bornean Orangutan and Bornean Sun Bear already have a very limited range and are extremely isolated.
- Small
population sizes: Many island species already exist in low numbers,
making them more vulnerable to habitat loss and unexpected events such as sudden floods, fires or disease outbreaks.
- Edge effects: Fragmentation increases exposure to wind, heat, and invasive species, including humans, degrading remaining forest patches faster.
- Isolation amplifies extinction risk: Unlike continental forests, islands don’t have nearby refugia or corridors for recolonisation.
Lesson from the Mentawai Islands
The Mentawai Islands, 150 km off the coast of Sumatra, illustrate what happens when plant and animal communities become isolated and their habitat diminishes. Separated from the ‘mainland’ around 500,000 years ago, no less than 17 endemic mammals evolved—particularly unique primates that are also hunted for food. In the last two decades, clearing for plantations has reduced the forest area by 50% and also reduced their numbers by 50%, with at least four now endangered or critically endangered, especially the striking Mentawai Langur and the Pig-Tailed Snub-Nosed Monkey.
| Region | Forest Loss Trends | Key Drivers | Conservation & Restoration Activity |
|---|---|---|---|
| Peninsular Malaysia | Substantial loss of lowland dipterocarp forests ~2.7 million ha primary forest lost (2002–2020) or 33% Fragmentation of protected areas |
Oil palm expansion Logging (legal & illegal) Infrastructure and mining |
Central Forest Spine connectivity plan Revised National Forestry Bill (2022) Strengthened forest reserve protection |
| Sumatra | ~56% forest cover lost since 1985 Rapid peat swamp degradation Highly fragmented lowland forests |
Palm oil and pulpwood plantations Peatland fires and drainage Illegal logging |
Thirty Hills restoration concession (PT ABT) Merang peatland rewetting project REDD+ pilots and community partnerships |
| Java | Extensive historical deforestation High population pressure |
Agricultural expansion Urban development Mountain encroachment |
Community forest management Protection of Javan Hawk-Eagle and gibbons Reforestation in degraded uplands |
| Bali | ~11% natural forest cover remains Low recent loss Vulnerable to erosion and tourism pressure |
Tourism development Agroforestry expansion Clearing of steep slopes increases landslip risks |
West Bali National Park conservation Perancak mangrove restoration Village-led reforestation (e.g. Penyaringan) Forest zoning and disaster mitigation planning |
Malaysia
Between 2002 and 2021 Malaysia lost 2.77 million ha of primary humid forest – around 33% of its tree cover with timber plantations accounting for around 40% of the loss.
With a further 16% of it’s remaining forest cover threatened by expansion of monocultures and other developments, Malaysia is at risk of breaching its 1994 pledge at the Rio Earth Summit to retain at least 50% of its forest cover, so its Government is beginning to take stronger action to address these issues.
It hopes it hopes to reverse this trend its new Forestry Bill (2022) calling for harsher penalties for illegal activities as well as public hearings prior to degazetting forest reserves.
Jewel in the crown in conservation terms is the Central Forest Spine Project which seeks to restore and reunite four major forest segments with “corridors of connectivity” down the length of Peninsular Malaysia so that animals can once again move more freely. For a rather lovely presentation about this, click here.
Conservation organisations such as World Wildlife Fund
Malaysia continue to advocate for species protection, research and by encouraging community forestry.
However, progress is slow and challenges remain. There is little data and little transparency around the matter of forestry concessions and indigenous communities continue to advocate for ancestral lands though these may overlap with forested areas under threat.
Borneo
Borneo is the world's third largest island. Both Borneo and Sumatra have had the highest proportional forest loss since 2000. Since the 1980s, over half of Kalimantan’s lowland forests—the Indonesian part of Borneo—have been cleared, mostly for palm oil plantations, which expanded from 600,000 hectares in 1985 to 6 million hectares by 2007. In South Kalimantan, 2,220 hectares were lost in 2024 alone.
Logging, both legal and illegal, has opened previously inaccessible regions to settlement, further degradation and poaching. Mining for coal and gold is also expanding with little environmental oversight. Unique species such as sun bears, which depend on tall trees and intact forests, are increasingly pushed into fragmented habitat.
Progress has been made in East Borneo, with deforestation declining in 2024 due to stronger governance and REDD+ programs. These World Bank-supported initiatives pay local communities to protect forests through emission reduction schemes. For details, see the Berau Province pilot program.
Begun in 2008 and covering 1.7 million hectares of primary forest and 0.5 million hectares of non-forest land, the initiative was backed by donors from Germany, Norway, Australia, the USA, and Indonesia. It has helped Berau Province retain 75% of its forest cover and enabled co-management opportunities through community forestry, rubber agroforestry, and forest patrols—benefiting about 1,500 orangutans and 80 threatened species.
Yet only 17% of Berau’s forests are formally protected. Pressures from palm oil, mining, and forestry continue to grow, and the program still relies on donor funding, as no carbon credits have been sold. A new threat is the relocation of Indonesia’s capital to Nusantara—its new “green city in the forest.” A toll road has already been cut from the coast through primary forest and buffer zones around protected areas, with speculation and land clearing occurring without regard to ownership.
Since 2009 Japanese Company Sumitomo Forestry has been working with Indonesian groups on fire prevention in its forestry concessions, particularly in peatlands which are widely distributed throughout Indonesia and especially in Kalimantan and Sumatra. Their approach focuses on maintaining groundwater levels and keeping peat moist and less flammable by careful zoning and canal maintenance. During the devastating 2015 fires, their managed areas reported no incidents thanks to careful hydrological zoning and canal maintenance.
More recently, they've introduced AI-based monitoring tools
to help predict fire risks and support local training in water control and
agroforestry—serving as a model for low-emission, community-led forestry.
Sumatra
Sumatra lost 56% of its forest cover between 1985 and 2016. However, the World Wildlife Fund Indonesia and partners have helped turn things around by establishing the Tesso Nilo National Park and ecosystem restoration concessions in the Thirty Hills (Bukit Tigapuluh) region. These restore former logging concessions beyond the park boundaries to safeguard Sumatra's endangered species, create livelihoods for local communities and preserve the estimated 11.5 million metric tons of CO2 stored by the forest.
Since 2023 57,000 seedlings have been planted on 502 ha of degraded land and 11,000 ha have been allowed to recover naturally, with help from anti -logging patrols and satellite monitoring. About half the villages now have access to improved medical care and some have been able to switch to sustainable production of honey and jungle rubber. Despite 'zero deforestation pledges,' pressure from pulp and palm oil industries continues.
Bird -Led Recovery
An interesting combination of local knowledge and modern technology is being applied in two projects in Sumatra. In Jambo Papeun Village in northern Sumatra, villagers noticed that crops of nutmeg began to decline once birds disappeared because insectivorous birds tended reduce disease outbreaks and keep forests healthy. They have since been working with conservation groups to monitor forests, stop poachers and restore 653 ha of previously logged forest. The birds in turn help to reseed the forest and support crop health. Villagers also have the right to use traditional punishments to those who break the rules, but forest law enforcement may be called in, should this fail. Public education in the importance of conserving both the birds and the forests is seen as another vital component in this strategy.
A similar program running at Harapan in the south of Sumatra has not been quite as successful. Although forests have recovered somewhat since 2007 when the project began, it is feared that continued trapping of birds has not allowed them or the forest to recover to the same extent. For more on what's happening to Sumatra see the Mongabay posts on this topic.
Java
Deforestation in Java’s forests began centuries ago for agriculture, colonial plantations and urban expansion. What remains is heavily fragmented and largely confined to a few isolated patches of natural forest in mountainous areas and some community managed patches.
Being home to its own set of endemic and endangered species, including the Javan Rhino, the Javan Hawk Eagle, several endangered primates including the Javan Gibbon and the Javan Slow Loris and some 30 species of birds, conservation efforts have focused on montane forests, where biodiversity remains relatively intact, though pressures for food security and forest products have increased and numbers of Javan Hawk Eagles have declined. Conserving Endangered Wildlife in Java – Rainforest Trust
For this reason, projects like those led by Rainforest Trust and Burung Indonesia – the Indonesian partner of Birdlife International, aim to create new protected areas in areas such as Gunung Gede and Gunung Patuha, to protect habitat for species such as the Javan Green Magpie and Rufous-fronted Laughingthrush, both of which are almost extinct due to trapping for the bird trade. Indonesia - Burung Indonesia - BirdLife International
Bali
Bali, that beloved home away from home for Australian tourists, has only 11% of its forest cover left. While mountain forests are officially protected, many forested areas are degraded, leading to increased risk of landslides.
Others are threatened by encroachment and fragmentation due to expansion of agriculture, roads and tourism developments, especially at the margins.
However, community led forest management and restoration are gaining traction. Recent attention to disaster preparation focuses on satellite mapping of fragile areas and promotes reforestation to help stabilise the slopes.
Many thanks to Microsoft Copilot for help with maps, tables formatting and information.
Next time: The even stranger world of Wallacea
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