Himalayan subtropical broadleaf forests
Encyclopedia
The Himalayan subtropical broadleaf forests is an ecoregion that extends from the middle hills of central Nepal
through Darjeeling into Bhutan
and also into the India
n State of Uttar Pradesh
. It represents the east-west-directed band of subtropical broadleaf forest
at an altitude of between 500 to 1000 m (1,640.4 to 3,280.8 ft) along the Outer Himalayan Range, and includes several forest types traversing an east to west moisture gradient.
deposited over the ages by the rivers that drain this young mountain range.
At lower elevations, the ecoregion is flanked by the Terai-Duar savannas and grasslands. Above 1000 m (3,280.8 ft), it yields to the Himalayan subtropical pine forests
.
Rainfall varies from east to west, but annual rainfall can be as much as 2000 mm (78.7 in). The Himalayas capture moisture from the monsoon
s that sweep in from the Bay of Bengal
, and most of this rainfall is expended in the eastern Himalayas. Therefore, the western Himalayas are drier, a trend reflected in the timberline that declines from 4000 m (13,123.4 ft) in the east to about 3500 m (11,482.9 ft) in the west.
Two high-priority Tiger
Conservation Units (TCU) extend across adjacent ecoregions:
n and Palearctic
ecozone
s. The main forest types include Dodonaea
scrub, subtropical dry evergreen forests of Olea cuspidata, northern dry mixed deciduous forests, dry Siwalik sal (Shorea robusta) forests, moist mixed deciduous forests, subtropical broadleaf wet hill forests, northern tropical semi-evergreen forests, and northern tropical wet evergreen forests.
, including the Bengal tiger
, Indian elephant, smooth-coated otter
, clouded leopard, gaur, Sumatran serow, Irrawaddy squirrel, and particoloured flying squirrel. The endemic
golden langur is distributed in a small range and limited to the broadleaf forest north of the Brahmaputra River
. The bird fauna is very rich with more than 340 species. The chestnut-breasted partridge is endemic
; the globally threatened white-winged wood duck and five hornbill
species are found here.
Nepal
Nepal , officially the Federal Democratic Republic of Nepal, is a landlocked sovereign state located in South Asia. It is located in the Himalayas and bordered to the north by the People's Republic of China, and to the south, east, and west by the Republic of India...
through Darjeeling into Bhutan
Bhutan
Bhutan , officially the Kingdom of Bhutan, is a landlocked state in South Asia, located at the eastern end of the Himalayas and bordered to the south, east and west by the Republic of India and to the north by the People's Republic of China...
and also into the India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
n State of Uttar Pradesh
Uttar Pradesh
Uttar Pradesh abbreviation U.P. , is a state located in the northern part of India. With a population of over 200 million people, it is India's most populous state, as well as the world's most populous sub-national entity...
. It represents the east-west-directed band of subtropical broadleaf forest
Tropical and subtropical moist broadleaf forests
Tropical and subtropical moist broadleaf forests , also known as tropical moist forests, are a tropical and subtropical forest biome....
at an altitude of between 500 to 1000 m (1,640.4 to 3,280.8 ft) along the Outer Himalayan Range, and includes several forest types traversing an east to west moisture gradient.
Landscape
The ecoregion covers an area of 38200 sqkm and is bisected by the Kali Gandaki River, which has gouged the world's deepest river valley through the Himalayan Range. It forms a critical link in the chain of interconnected Himalayan ecosystems, where altitudinal connectivity between the habitat types is important for ecosystem function. The soil is composed of alluviumAlluvium
Alluvium is loose, unconsolidated soil or sediments, eroded, deposited, and reshaped by water in some form in a non-marine setting. Alluvium is typically made up of a variety of materials, including fine particles of silt and clay and larger particles of sand and gravel...
deposited over the ages by the rivers that drain this young mountain range.
At lower elevations, the ecoregion is flanked by the Terai-Duar savannas and grasslands. Above 1000 m (3,280.8 ft), it yields to the Himalayan subtropical pine forests
Himalayan subtropical pine forests
The Himalayan subtropical pine forests are a large subtropical coniferous forest ecoregion covering portions of Bhutan, India, Nepal, and Pakistan....
.
Rainfall varies from east to west, but annual rainfall can be as much as 2000 mm (78.7 in). The Himalayas capture moisture from the monsoon
Monsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...
s that sweep in from the Bay of Bengal
Bay of Bengal
The Bay of Bengal , the largest bay in the world, forms the northeastern part of the Indian Ocean. It resembles a triangle in shape, and is bordered mostly by the Eastern Coast of India, southern coast of Bangladesh and Sri Lanka to the west and Burma and the Andaman and Nicobar Islands to the...
, and most of this rainfall is expended in the eastern Himalayas. Therefore, the western Himalayas are drier, a trend reflected in the timberline that declines from 4000 m (13,123.4 ft) in the east to about 3500 m (11,482.9 ft) in the west.
Protected areas
Eight protected areas extend into this ecoregion covering 2710 km² (1,046.3 sq mi), which is about 7% of the ecoregion's area:- in India: Sohagabarwa Wildlife Sanctuary and Valmiki National ParkValmiki National ParkValmiki National Park is located in the West Champaran district of Bihar, India. The extensive forest area of Valmikinagar was owned by the Bettiah Raj and Ramanagar Raj until early 1950s...
; - in Nepal: Bardia National Park, Chitwan National Park, Parsa Wildlife ReserveParsa Wildlife ReserveParsa Wildlife Reserve is a protected area in the Inner Terai lowlands of south-central Nepal. Established in 1984, it covers an area of in the Parsa, Makwanpur and Bara districts and is the largest wildlife reserve in the country...
; - in Bhutan: Royal Manas National ParkRoyal Manas National ParkRoyal Manas National Park is Bhutan's oldest national park, and the Royal government considers it the "conservation showpiece of the Kingdom" and a "genetic depository" for valuable plants. It has an area of and covers eastern Sarpang District, the western half of Zhemgang District, and western...
, Khaling Wildlife SanctuaryKhaling Wildlife SanctuaryKhaling Wildlife Sanctuary is the smallest protected area of Bhutan covering in Samdrup Jongkhar District along the southern border with Assam. Its elevations range between and . Khaling Wildlife Sanctuary is, despite its small acreage, an important habitat for elephants, gaur , and other...
and Phibsoo Wildlife SanctuaryPhibsoo Wildlife SanctuaryThe Phibsoo Wildlife Sanctuary is the second-smallest national park in Bhutan, covering in western Sarpang District and southeastern Dagana District along the border with West Bengal. It is connected to Jigme Singye Wangchuck National Park and Royal Manas National Park via a "biological corridor"...
.
Two high-priority Tiger
Bengal Tiger
The Bengal tiger is a tiger subspecies native to the Indian subcontinent that in 2010 has been classified as endangered by IUCN...
Conservation Units (TCU) extend across adjacent ecoregions:
- Chitwan-Parsa-Valmiki TCU covers a 3549 km² (1,370.3 sq mi) huge block of alluvial grasslands and subtropical moist deciduous forests;
- Bardia-Banke TCU covers 1518 km² (586.1 sq mi).
Vegetation
The ecoregion hosts a broad range of plant communities, based on its complex topography, differing soils, and variations in rainfall from the drier west to the more humid east. Its location on the south slope of the Himalaya allows the intermingling of plants and animals from the IndomalayaIndomalaya
The Indomalaya ecozone is one of the eight ecozones that cover the planet's land surface. It extends across most of South and Southeast Asia and into the southern parts of East Asia....
n and Palearctic
Palearctic
The Palearctic or Palaearctic is one of the eight ecozones dividing the Earth's surface.Physically, the Palearctic is the largest ecozone...
ecozone
Ecozone
An ecozone is the broadest biogeographic division of the Earth's land surface, based on distributional patterns of terrestrial organisms.Ecozones delineate large areas of the Earth's surface within which organisms have been evolving in relative isolation over long periods of time, separated from...
s. The main forest types include Dodonaea
Dodonaea
Dodonaea is a genus of about 70 species of flowering plants in the soapberry family, Sapindaceae, with a cosmopolitan distribution in tropical, subtropical and warm temperate regions of Africa, the Americas, southern Asia and Australasia. By far the highest species diversity is in Australia...
scrub, subtropical dry evergreen forests of Olea cuspidata, northern dry mixed deciduous forests, dry Siwalik sal (Shorea robusta) forests, moist mixed deciduous forests, subtropical broadleaf wet hill forests, northern tropical semi-evergreen forests, and northern tropical wet evergreen forests.
Fauna
Several mammals native to the ecoregion are threatenedThreatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...
, including the Bengal tiger
Bengal Tiger
The Bengal tiger is a tiger subspecies native to the Indian subcontinent that in 2010 has been classified as endangered by IUCN...
, Indian elephant, smooth-coated otter
Smooth-coated Otter
The Smooth-coated Otter is a species of otter, the only extant representative of the genus Lutrogale. The species is found from southern Pakistan and parts of the India east to Southeast Asia, and there is a disjunct population in Iraq...
, clouded leopard, gaur, Sumatran serow, Irrawaddy squirrel, and particoloured flying squirrel. The endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
golden langur is distributed in a small range and limited to the broadleaf forest north of the Brahmaputra River
Brahmaputra River
The Brahmaputra , also called Tsangpo-Brahmaputra, is a trans-boundary river and one of the major rivers of Asia. It is the only Indian river that is attributed the masculine gender and thus referred to as a in Indo-Aryan languages and languages with Indo-Aryan influence...
. The bird fauna is very rich with more than 340 species. The chestnut-breasted partridge is endemic
Endemism in birds
An endemic bird area is a region of the world that contains two or more restricted-range species, while a "secondary area" contains one or more restricted-range species. Both terms were devised by Birdlife International....
; the globally threatened white-winged wood duck and five hornbill
Hornbill
Hornbills are a family of bird found in tropical and subtropical Africa, Asia and Melanesia. They are characterized by a long, down-curved bill which is frequently brightly-colored and sometimes has a casque on the upper mandible. Both the common English and the scientific name of the family...
species are found here.