The Sumatran montane rain forests

ecoregion An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of l ...

(WWF ID: IM0159) covers the mountainous elevations (greater than 1,000 meters) of the

Barisan Mountains The Bukit Barisan or the Barisan Mountains are a mountain range on the western side of Sumatra, Indonesia, covering nearly 1,700 km (1,050 mi) from the north to the south of the island. The Bukit Barisan range consists primarily of volca ...

Range that runs the length of the southwestern side of the island of

Sumatra Sumatra is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the sixth-largest island in the world at 473,481 km2 (182,812 mi.2), not including adjacent i ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

. The ecoregion is almost completely surrounded by the lower elevation

Sumatran lowland rain forests The Sumatran lowland rain forests ecoregion (WWF ID: IM0158) covers the lowland forests running the length of the island of Sumatra in Indonesia. The region is one of exceptionally high biodiversity, similar to Borneo and New Guinea islands. Ma ...

. The area is one of very high biodiversity - because of the relative isolation, and variety of forest types, there are 7 endemic species of mammals and eight endemic species of birds.

Location and description

The Barisan Mountains stretch for 1,600 km along the southwest side of Sumatra, the product of the subducting Australia Plate and the overriding

Sunda Plate The Sunda Plate is a minor tectonic plate straddling the Equator in the Eastern Hemisphere on which the majority of Southeast Asia is located. The Sunda Plate was formerly considered a part of the Eurasian Plate, but the GPS measurements have ...

. The range averages less than 70 km wide, and rises from 44 meters to a maximum elevation of , with a mean elevation of . There are 35 active volcanoes in the region, with the western side steeper, and the eastern slide inclining to lowlands and plains.

Climate

The climate of the ecoregion is ''

Tropical rainforest climate A tropical rainforest climate, humid tropical climate or equatorial climate is a tropical climate sub-type usually found within 10 to 15 degrees latitude of the equator. There are some other areas at higher latitudes, such as the coast of southea ...

'' (

Köppen climate classification The Köppen climate classification is one of the most widely used climate classification systems. It was first published by German-Russian climatologist Wladimir Köppen (1846–1940) in 1884, with several later modifications by Köppen, notabl ...

(Af)). This climate is characterized as hot, humid, and having at least 60 mm of precipitation every month. Annual precipitation in the mountains averages 2,500 mm. The eastern side of the Barisan Mountains are in a rain shadow, and receive less precipitation than the west side.

Flora and fauna

75% of the ecoregion is covered with closed, broadleaf evergreen forest, another 15% in other types of closed forest, and 7% open forest. There are three main forest types in the ecoregion, based on elevation: the 'lower montane forest', 'upper montane forest', and 'sub-alpine forest'. The lower montane forest has tree species similar to the lowland rain forests, but they are shorter (up to 35 meters), buttresses are rare, llianas (woody vines) are rare,

epiphytes An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...

become more common, and the lowland domination of trees of the family

Dipterocarpaceae Dipterocarpaceae is a family of 16 genera and about 695 known species of mainly tropical lowland rainforest trees. The family name, from the type genus ''Dipterocarpus'', is derived from Greek (''di'' = two, ''pteron'' = wing and ''karpos'' = fru ...

gives way to more trees of the oak family

Fagaceae The Fagaceae are a family of flowering plants that includes beeches, chestnuts and oaks, and comprises eight genera with about 927 species. Fagaceae in temperate regions are mostly deciduous, whereas in the tropics, many species occur as evergre ...

, such as stone oaks ''(

Lithocarpus ''Lithocarpus'' is a genus in the beech family, Fagaceae. Trees in this genus are commonly known as the stone oaks and differ from ''Quercus'' primarily because they produce insect-pollinated flowers on erect spikes and the female flowers have ...

)'', and of the laurel family

Lauraceae Lauraceae, or the laurels, is a plant family that includes the true laurel and its closest relatives. This family comprises about 2850 known species in about 45 genera worldwide (Christenhusz & Byng 2016 ). They are dicotyledons, and occur ma ...

, such as ''

Cinnamomum burmannii ''Cinnamomum burmannii'' (or ''Cinnamomum burmanni''), also known as Indonesian cinnamon, Padang cassia, Batavia cassia, or korintje, is one of several plants in the genus ''Cinnamomum'' whose bark is sold as the spice cinnamon. The most common ...

''. The upper montane forest forms at higher elevations, depending on temperature and cloud level. The trees in this zone are shorter (up to 20 meters, and epiphytes, such as moss and lichens, are more common. The sub-alpine forest zone begins at higher elevations, and features grasses, heath, and bogs. Trees in the sub-alpine zone are scattered and stunted, typically under 10 meters in height. Mammals of conservation interest include the vulnerable Thomas's langur ''( Presbytis thomasi)'', the vulnerable Sumatran striped rabbit ''(

Nesolagus netscheri The Sumatran striped rabbit (''Nesolagus netscheri''), also known as the Sumatra short-eared rabbit or Sumatran rabbit, is a rabbit found only in forests in the Barisan Mountains in western Sumatra, Indonesia, and surrounding areas. It is threat ...

)'', and the Sumatran tiger ''(

Panthera tigris The tiger (''Panthera tigris'') is the largest living cat species and a member of the genus '' Panthera''. It is most recognisable for its dark vertical stripes on orange fur with a white underside. An apex predator, it primarily preys on u ...

)''.

Protected areas

Over 31% of the ecoregion is officially protected. The protected areas include: *

Mount Leuser National Park Gunung Leuser National Park is a national park covering 7,927 km2 in northern Sumatra, Indonesia, straddling the border of North Sumatra and Aceh provinces, a fourth portion and three-fourths portion, respectively. The national park, settled ...

Bukit Barisan Selatan National Park Bukit Barisan Selatan National Park is a national park in Sumatra, Indonesia. The park located along the Bukit Barisan mountain range, has a total area of 3,568 km2, and spans three provinces: Lampung, Bengkulu, and South Sumatra. Together ...

Kerinci Seblat National Park Kerinci Seblat National Park is the largest national park on the island of Sumatra, Indonesia. It has a total area of 13,791 km2, and spans four provinces: West Sumatra, Jambi, Bengkulu, and South Sumatra. Geography It is located between 1 ...

* Batang Gadis National Park

References

{{reflist Indomalayan ecoregions Ecoregions of Indonesia Tropical and subtropical moist broadleaf forests Montane forests Geography of Sumatra Flora of Sumatra Ecoregions of Malesia