Deep in northern Sumatra, Indonesia, is the Leuser Ecosystem, one of the world's most important remaining tropical rainforest landscapes. It covers nearly 2.6 million hectares across Aceh and North Sumatra provinces and has a wealth of threatened wildlife in it.
It is particularly important because it remains one of the few places where Sumatran orangutans, elephants, tigers and rhinos coexist in the wild. Conservation organisations say Leuser is the only place where these four iconic Sumatran species still live together in the same landscape.
As well as the conservation efforts of actor and environmentalist Leonardo DiCaprio.
Leonardo DiCaprio's support of Leuser Conservation
DiCaprio has been involved in conservation efforts in the Leuser Ecosystem for years through the Leonardo DiCaprio Foundation.
In 2016, his foundation provided funding to conservation groups working to protect the Leuser landscape. Mongabay reported that around $3.2 million was awarded to the Rainforest Action Network and HAkA to protect the ecosystem from deforestation and development.
In a 2016 trip to Sumatra, DiCaprio also visited the Leuser Ecosystem and met organisations working to protect the rainforest. At the time, the Leonardo DiCaprio Foundation was working with local partners to establish a large wildlife sanctuary in the region.
The conservation work focused on protecting habitat for some of Sumatra's most threatened species and addressing pressures from activities like palm oil expansion, logging, mining and infrastructure development.
Therefore, the support should be seen as part of DiCaprio’s wider environmental philanthropy rather than as a new fund announced in 2026.
Why The Leuser Ecosystem Is So Important
The Leuser Ecosystem is much larger than a traditional protected park. It includes lowland rainforests, montane forests, peatlands, rivers and other habitats across northern Sumatra.
The landscape also supports more than 130 mammal species and hundreds of bird species as well as thousands of plants. It also includes breeding populations of Sumatran orangutans, elephants, tigers and rhinos.
The importance of the ecosystem extends beyond wildlife.
The forests and peatlands provide water resources and support the livelihoods of millions of people in Aceh and North Sumatra. They also hold significant amounts of carbon and help regulate water flows, so their protection is important for biodiversity and local communities.
The United Nations has also described the Leuser landscape as a unique environment where elephants, rhinos, tigers and orangutans continue to roam together in the wild.
Tigers, Elephants And Orangutans face growing threats.
As important as it is to the ecological process, the Leuser Ecosystem is under ever-growing pressure.
Land conversion for plantations, illegal logging, mining, infrastructure development, agricultural expansion and poaching have all been identified as threats to the landscape. Human-wildlife conflict is another concern, particularly in areas where farms and settlements overlap with wildlife habitat.
For species such as the Sumatran tiger, elephant, orangutan and rhino, habitat fragmentation can make it harder to find food, reproduce and move safely between forest areas.
Conservation organizations are more involved in forest patrols, wildlife monitoring, habitat restoration, community development and avoiding conflict with animals.
The Leuser Conservation Forum, for example, has wildlife and elephant patrols and works with local communities on forest protection and restoration.
Why protecting Leuser matters beyond Indonesia
In spite of the wildlife in the Leuser ecosystem, it has a global biodiversity value in nature.
Sumatran orangutans, tigers, elephants and rhinos are all threatened species, and the survival of their remaining populations depends heavily on protecting their habitats.
Research published in Frontiers in Ecology and Evolution describes the 2.6-million-hectare Leuser Ecosystem as one of the most intact rainforest landscapes in Southeast Asia and mentions that it is the only place where the Sumatran tiger, Sumatran rhino, Sumatran orangutan and Sumatran elephant coexist.
The ecosystem is also part of the wider Tropical Rainforest Heritage of Sumatra, a UNESCO-recognised World Heritage landscape.
Because for environmental campaigners, protecting Leuser is so much more than just saving animals. It is protecting an interconnected rainforest system that supports wildlife, people, water resources and carbon storage.
Leonardo DiCaprio’s involvement helped bring international attention to that cause, but conservation in Leuser requires long-term work by local communities, Indonesian authorities and conservation organisations working on the ground.
As pressure on tropical forests and habitat is growing around the world, the Leuser Ecosystem is a good example of what is at stake when an intact environment is increasingly fragmented and why, for species that have absolutely no other option as a refuge, preserving such habitats is crucial.
