The Leuser Ecosystem is named after the next highest mountain in Sumatra, namely Mount Leuser (3,404 m). Leuser origins from the Gayo word Leusoh meaning “covered by clouds”. Another meaning of the word is “the last wildlife paradise”.

1. Dimensions of the Leuser Ecosystem

The Leuser Ecosystem constitutes the third largest tropical rainforest complex in the world, after the Amazon forest in Brazil and the Zaire forest in Africa. Located in the northern part of the Sumatran island, authoritatively this area belongs to the provinces of Aceh and North Sumatra. More precisely the geographical position of the Leuser Ecosystem is 2.250 – 4.950 North and 96.350 – 98.550 East. The average rainfall per year is 2544 mm and the average temperature is 26 degrees Celsius during the day and 21 degrees Celsius at night.

The Leuser Ecosystem covers an area of 2,634,874 hectares. The bigger part is located in Aceh (2,255,577 hectares) and the rest in North Sumatra (384,297 hectares). The area stretches over 13 districts including 875 villages in Aceh and 4 districts including 128 villages in North Sumatra.

The Leuser Ecosystem landscape consists of a wide range of habitats including beaches, swamps, rivers, lowlands, highlands and mountains covered in clouds. According to the decree of the Minister of Forestry concerning the borders of the Leuser Ecosystem, the area consists of:

- Protected forests (± 941,713 hectares)
- The Mount Leuser National Park (± 602,582 hectares)
- Rawa Singkil Wildlife Reserve (± 102,370 hectares)
- Lingga Isaq Hunting Park (± 29,090 hectares)
- Limited production forest (± 8,066 hectares)
- Production forest (± 245,676 hectares)
- Other Uses Area (± 326.080 hectare)- Lakes (± 145 hectare)
- Ocean/rivers/water (± 3.721 hectare)

2. Biodiversity

Research conducted by experts show that at least 45% of the total estimated number of plant species in the West Indo-Malay region, 85% of the total estimated number of bird species and 54% of the total estimated number of animal species in Sumatra can be found in the Leuser Ecosystem. The Leuser Ecosystem stores 4,500 flora and fauna species comprising a huge germ plasm resource.

The documented species includes 710 animal species (including 128 mammalian species, 424 bird species, 96 amphibian species and 24 fish species) amongst which 180 varieties have been declared as endangered species. Leuser is unique as it is the only ecosystem in the world where five rare wildlife species live side by side in the same region, i.e. the Sumatran Elephant (Elephas maximus), the Kappi, Sikundur and Sembala highlands into the Mount Leuser Wildlife Reserve (1970’s), reassigning the Mount Leuser Wildlife Reserve as a National Park (1980), and initiating collaboration between the Indonesian Government and the European Union to conserve Leuser (1991).

The Leuser Ecosystem was legalised through a decree of the Minister of Forestry No. 227/KPTS-II/1995 and was further strengthened by Presidential Decree No. 33/1998, the Minister of Forestry’s Decree No. 190/Kpts-II/2001 (concerning the Leuser Ecosystem boundary in Aceh), the Minister of Forestry’s Decree No. 10193/KPTS-II/2002 (concerning the Leuser Ecosystem boundary in North Sumatra), law No. 11/2006 concerning the Acehnese Government and the Government Regulation No. 26/2008 establishing the Leuser Ecosystem as a national strategic area.

The founders of the LIF include H. Bustanil Arifin, SH, H. Abdul Rachman Ramly, Prof. Dr. Ibrahim Hasan, MBA, Prof. Dr. Syamsuddin Mahmud, Drs. H. Sayed Mudhahar Ahmad, Drs. Nurdin Abdul Rachman, Drs. H. Teuku Iskandar and Mike Griffiths.