Sundaland Rainforest
The Sundaland rainforest stretches across thousands of islands in Southeast Asia, including Sumatra, Borneo, Java, the Malay Peninsula and many smaller ones. It is one of the most biodiverse regions on Earth, with three species of tiger and one of the last places where tigers and orangutans still live in the wild. Sadly, it is also one of the most threatened, having lost about half of its original forest cover.
- Areaapprox. 1 million km²Spread across many islands
- CountriesMalaysia, Indonesia, Brunei, SingaporePlus southern Thailand
- Famous animalsTiger, rhino, orangutanPlus tapirs, gibbons and sun bears
- Plant speciesOver 25,000About 10% of the world total
- Biggest threatPalm oil farmingPlus illegal logging and fires
- Forest lostapprox. 50%Mostly in the last 50 years
Where Sundaland fits in
Sundaland is roughly the same size as Western Europe. It is the western half of the great Southeast Asian rainforest region.
What is the Sundaland Rainforest?
Sundaland is a vast tropical rainforest spread across the islands of Sumatra, Borneo and Java, plus the Malay Peninsula (Peninsular Malaysia and southern Thailand) and Singapore. The name comes from the Sunda Shelf, the partly-submerged stretch of continental crust on which these islands sit. During the last ice age, the shelf was above sea level and all of these islands were connected to mainland Asia. The rainforest covered the whole region as one continuous block.
Critically endangered megafauna
Sundaland is the only place where rainforest tigers, rhinos and orangutans still live together in the wild. All of them are critically endangered.
- Sumatran tigers: only approx. 400 left in the wild, on the island of Sumatra. The other two species, the Javan and Bali tigers, are already extinct.
- Sumatran rhinos: fewer than 80 remain. Once spread across all of Sundaland, they are now restricted to a few protected areas on Sumatra and Borneo.
- Sumatran and Bornean orangutans: critically endangered. Sumatran orangutans number around 14,000, Bornean orangutans around 100,000.
The Malay Peninsula
The Malay Peninsula extends south from mainland Asia like a long thumb pointing towards Singapore. It is covered in dense tropical rainforest at its heart, much of it protected in national parks such as Taman Negara (one of the oldest rainforests in the world, around 130 million years old). The peninsula is also one of the most densely populated parts of Southeast Asia, and the forest competes with cities, palm oil plantations and roads.
Deforestation and palm oil
Sundaland has lost about half of its original forest cover, mostly in the last 50 years. The main driver is the same as on neighbouring Borneo: palm oil. Indonesia and Malaysia together produce around 85% of the world's palm oil, almost all of it on land that used to be rainforest. The annual "haze" of smoke from forest and peat fires used to clear land regularly chokes the cities of Singapore, Kuala Lumpur and Jakarta.
Deeper dive: ice-age Sundaland, Wallacea and the orangutan crisis
During the most recent ice ages (which ended approx. 12,000 years ago), so much of the world's water was locked up in glaciers that sea levels were around 120 metres lower than today. The shallow seas of the Sunda Shelf were dry land, and the islands of Sumatra, Java and Borneo were all connected to each other and to mainland Asia as a single huge peninsula. Plants and animals moved freely across this Sundaland. When the ice melted and sea levels rose, the lowlands were flooded and Sundaland broke apart into the islands we see today. The rainforest survived on each island but populations of many species (including orangutans, tigers and elephants) became isolated and gradually evolved into distinct subspecies and species.
Just east of Sundaland is the biogeographically unique region called Wallacea, the chain of islands stretching from Sulawesi to Timor. The deep-water trenches between these islands meant they were never connected to Sundaland, even at the lowest sea levels. As a result Wallacea has a unique fauna mixed from both the Asian (Sundaland) side and the Australian (Sahul) side, with a remarkable number of endemic species. Alfred Russel Wallace identified this division and proposed his "Wallace Line" through the region.
The orangutan situation in Sundaland is now considered one of the most urgent conservation crises in the world. Population genetics show that the Sumatran and Bornean orangutans split from each other around 700,000 years ago, and were recently joined by a third species (the Tapanuli orangutan, described from a tiny population in northern Sumatra in 2017). The Tapanuli population is the most endangered great ape on Earth, with fewer than 800 individuals and ongoing threats from a hydroelectric dam project in their only remaining habitat.
For Borneo specifically, see the Borneo Rainforest. The main country in Sundaland is Indonesia.