Gunung Leuser, Indonesia

Gunung Leuser, Indonesia Photo
©Peter Clyne/WCS

The Leuser Ecosystem is one of the last remaining true wilderness areas in Indonesia. This vast landscape spans lowland evergreen dipterocarp forest, lower and upper montane rainforest, peat swamp forest, sub-alpine meadows and heathlands, freshwater lakes and rivers, and sulphur mineral pools. Sumatran rhinos, Asian elephants, and sun bears pad through the forests, orangutans and gibbons swing through the trees, and crocodiles and fish swim its waters. The landscape is also a refuge for hornbills and hundreds of other bird species.

Fast Facts

  • Gunung Leuser is without a doubt the most important landscape for the continued survival of the Sumatran tiger.
  • It is one of the three national parks within the Tropical Rainforest of Heritage of Sumatra—a UNESCO World Heritage site.
  • Walking across the Leuser Ecosystem could take a month, without ever leaving primary rainforest and without meeting a single road or village.


The mountainous forest-covered interior of the Leuser Ecosystem is protected by its geography and remoteness. The borders of the area are not so safe, however, and are threatened by agricultural encroachment and conversion to industrial agriculture. Hunting also poses a threat to the wildlife within the region and conflicts between local villagers and tigers and elephants sometimes erupt.

WCS Responds

WCS began working in the Leuser Ecosystem in 2007 and, by partnering with local groups, we have steadily increased our activities and impact. Much of our work is focused on tiger conservation, in particular stopping hunting and trade of the big cats and their prey, and reducing tiger-human conflicts. We also promote environmentally beneficial rural livelihoods, conduct conservation education programs, and conserve elephants. Finally, in the three years since its inception, the work of our northern Sumatra Wildlife Crime Unit has resulted in the greatest number of arrests for the illegal trade in tiger parts witnessed in Indonesia.

From the Newsroom

Sumatra’s Last TigersFebruary 29, 2012

In this TV news segment, WCS’s Joe Walston is interviewed about the reasons behind a 2009 spate of Sumatran tiger attacks.

Saving the Last Strongholds for TigersSeptember 14, 2010

WCS-Russia director Dale Miquelle discusses the unique challenges of conserving Siberian tigers.

Wild Tiger Report CardFebruary 17, 2010

As the world celebrates the Year of the Tiger, WCS assesses tiger habitat and populations across eight priority landscapes in Asia with a color-coded report.

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