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February 28, 2019. Life / Islands


Nicholas D. Holmes, Olivier Langrand, Russell A. Mittermeier, Anthony B. Rylands, Thomas Brooks, Dena R. Spatz, James C. Russell, Wes Sechrest, Federico Mendez Sanchez

Sundaland is a biogeographic region of Southeast Asia. It covers the Malay Peninsula along with the three major islands of Borneo, Sumatra, and Java, besides multiple small islands in the Java Sea and to the west of Sumatra. Borneo is the third largest island on Earth and Sumatra the sixth, while Java is the most densely populated.

Borneo (725,500 km2) consists of extensive coastal plains in the south and west with a mountainous backbone running from the northeast into the central highlands. Borneo is dominated by tropical forest, from lowland rainforest to mountain heath forest. The rainforests are part of the most ancient forest on Earth, thought to be 130 million years old.

Sumatra (427,300 km2) is dominated by the Barisan Mountain range, a volcanic arc running the entire length of the island. Sumatra is the only place on Earth where tiger, rhinos, elephant and orangutans coexist.

Java (126,700 km2), like Sumatra, is a volcanic arc formed from the Java subduction zone. Its coastal zones are similarly broad on the Sunda Shelf side of the island and narrow on the Southern Australia Plate side.

The Mentawai Islands (6,011 km2) are a group of about 70 islands about 140 kilometers to the west of central Sumatra. There are four main islands, Siberut, Sipora, North Pagai, and South Pagai. These islands were separated from Sumatra more than half a million year ago, leading to the evolution of numerous endemic species.


This is an excerpt from the CEMEX Nature Series Book “Islands” (2018)

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