The highest point in this area is peak of Gunung Leuser (3450 m), and also the second highest point in Sumatra. Beside that, there are some areas that have elevation above 3000 m . Lembah Alas, with the highest point of Gunung Bendahara (2997 m), is also part of this area.Orang Utan Rehabilitation Centre in Bahorok-Bukit Lawang (North Sumatra) is visited by many tourists. Research station in Ketambe and National Park Head office located near Kutacane. Other popular activities are birdwathing and rafting in Alas River from Ketambe to Singkil (Griffiths 1992, Rijksen & Griffiths 1995)
This area contains lowland and mountain bird species. However some mountain species recorded in Gunung Kerinci, such as Schneider's Pitta Pitta schneider, Black-crowned Pitta Pitta venusta, and Sumatran Cochoa Cochoa beccarii are not recorded in this area. Other two species from this site, Hoogerwerf's Pheasant Lophura hoogerwerfi and Mountain Serin Serinus estherae, are not distributed to southern part of Sumatra. Based on newest data, Mountain Serin Serinus estherae is also found at Samosir Island, Lake Toba, as a result the distribution range not only in Gunung Leuser peak as mentioned in Marle & Voous (1988).Bird information from Kluet as part of this area from C.P. van Scahik (in litt. to D. Holmes, March 1993), mentioned that this area probably important for White-winged Duck Cairina scutulata population. Masked Finfoot Heliopais personata also reported in this area (Holmes 1996).Three days survey at Besitang by Chris Shepherd not found any important species (April 1999), but with some additional survey time more species are expected to be found in this area. Tropicoperdix charltonii which has been found near Kuala Simpang (300 m asl) probably also lives in this area. Trichastoma buettikoferi found at 100 m elevation at Bahorok, near to this area.
Non-bird biodiversity: Other biodiversity include Cuon alpinus, Dicerorhinus sumatraensis, Elephas maximus, Helarctos malayanus, Naemorhidus (Capricornis) sumatrensis, Panthera tigris, Hylobates lar, Hylobates syndactylus, Macaca nemestrina, Pongo pygmaeus, Presbytis thomasi, Presbytis cristata, Neofelis nebulosa, Felis bengalensis, Felis marmorata, Felis planiceps, Felis temminckii, Felis viverrensis, Nesolasgus netscheri, Tomistoma schlegelii,Varanus salvator, and fish species such as Tor soro and Hampala macrolepidota(Griffiths 1992, Anon 1995, Rijksen & Griffiths 1995, Colijn 1999).
Habitat and land use
Lowland evergreen rainforest, lower mountain rainforest and upper mountain rainforest. There are wetlands and arable areas (5%) along the coast. There are sub-alpin shrubs on the mountains top (Griffiths 1992, Anon 1995, Rijksen & Griffiths 1995, Colijn 1999).
Pressure/threats to key biodiversity
Illegal logging at the end of southern area, deforestation for plantation and shifting agriculture activities along Lembah Alas and wild hunting for collection and trade.
792675 ha (573690 ha in Nanggroe Aceh Darussalam province and 218985 ha in Sumatra Utara province) of this area has been declared as Gunung Leuser National Park based on SK Mentan No. 913/Kpts/Um/10/1982 on 30 October 1982 and SK Mentan No. 165/Kpts/Um/3/1982 (Anon 1995).Based on SK Menhut No. 276/Kpts-VI/97 on 23 May 1997, the area has been extended to 1,094,692 ha (Anon 1998).