The Brahmaputra Valley semi-evergreen forests is a tropical moist broadleaf forest

ecoregion An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and c ...

Northeastern India Northeast India, officially the North Eastern Region (NER), is the easternmost region of India representing both a geographic and political administrative division of the country. It comprises eight states—Arunachal Pradesh, Assam, Manipur, M ...

, southern

Bhutan Bhutan, officially the Kingdom of Bhutan, is a landlocked country in South Asia, in the Eastern Himalayas between China to the north and northwest and India to the south and southeast. With a population of over 727,145 and a territory of , ...

and adjacent

Bangladesh Bangladesh, officially the People's Republic of Bangladesh, is a country in South Asia. It is the List of countries and dependencies by population, eighth-most populous country in the world and among the List of countries and dependencies by ...

Location and description

The ecoregion covers and encompasses the

alluvial plain An alluvial plain is a plain (an essentially flat landform) created by the deposition of sediment over a long period by one or more rivers coming from highland regions, from which alluvial soil forms. A ''floodplain'' is part of the process, bei ...

of the upper

Brahmaputra River The Brahmaputra is a trans-boundary river which flows through Southwestern China, Northeastern India, and Bangladesh. It is known as Brahmaputra or Luit in Assamese language, Assamese, Yarlung Tsangpo in Lhasa Tibetan, Tibetan, the Siang/Dihan ...

as it moves westward through India's

Assam Assam (, , ) is a state in Northeast India, northeastern India, south of the eastern Himalayas along the Brahmaputra Valley, Brahmaputra and Barak River valleys. Assam covers an area of . It is the second largest state in Northeast India, nor ...

state (with small parts of the ecoregion in the states of

Arunachal Pradesh Arunachal Pradesh (; ) is a States and union territories of India, state in northeast India. It was formed from the North-East Frontier Agency (NEFA) region, and India declared it as a state on 20 February 1987. Itanagar is its capital and la ...

and

Nagaland Nagaland () is a States and union territories of India, state in the northeast India, north-eastern region of India. It is bordered by the Indian states of Arunachal Pradesh to the north, Assam to the west, Manipur to the south, and the Naga Sel ...

and also south

and northern

). The valley lies between the

Himalaya The Himalayas, or Himalaya ( ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the Earth's highest peaks, including the highest, Mount Everest. More than 100 pea ...

s to the north and the Lushai hills to the south and when the river floods during the June to September monsoon it brings up to 300 cm of water onto the plain carrying rich soils to create a fertile environment which has been extensively farmed for thousands of years. Other rivers that water the plains as well as the Brahmaputra include the Manas and the Subansiri.

Flora

The extensive farming has meant that the original semi-evergreen forest now exists only in patches. Typical canopy trees include the evergreen '' Syzygium,

Cinnamomum ''Cinnamomum'' is a genus of evergreen aromatic trees and shrubs belonging to the laurel family, Lauraceae. The species of ''Cinnamomum'' have aromatic oils in their leaves and bark. The genus contains approximately 234 species, distributed in ...

'' and

Magnoliaceae The Magnoliaceae () are a flowering plant family, the magnolia family, in the order Magnoliales. It consists of two genera: '' Magnolia'' and ''Liriodendron'' (tulip trees). Unlike most angiosperms, whose flower parts are in whorls (rings), ...

along with deciduous '' Terminalia myriocarpa, Terminalia citrina, Terminalia tomentosa,

Tetrameles ''Tetrameles'' is a genus of flowering plants in the family Tetramelaceae with one species, ''Tetrameles nudiflora''. It grows as a large deciduous tree and is found across southern Asia from India through southeast Asia, Malesia, and into northe ...

'' species. Understory trees and shrubs include the

laurels ''Laurus nobilis'' is an aromatic evergreen tree or large shrub with green, glabrous (smooth) leaves. It is in the flowering plant family Lauraceae. According to Flora Cretica (Kleinsteuber Books, 2024, ISBN 978-3-9818110-5-6) the stem can be 1 ...

'' Phoebe,

Machilus ''Machilus'' is a genus of flowering plants in the family Lauraceae. It is found in temperate, subtropical, and tropical forest, occurring in China, Korea, Japan, Taiwan, Indochina, the Indian subcontinent, Malaysia, Indonesia, and the Phili ...

'', and '' Actinodaphne'',

Polyalthia ''Polyalthia'' is a genus of flowering plants in the family Annonaceae. There are approximately 90 species distributed from Africa to Asia and the Pacific.

s, '' Aphanamixis'', and cultivated ''

Mesua ferrea ''Mesua ferrea'', the Ceylon ironwood, or cobra saffron, is a species in the family Calophyllaceae native to the Indomalayan realm. This slow-growing tree is named after the heaviness and hardness of its timber. It is widely cultivated as an o ...

'' and species of

mahogany Mahogany is a straight- grained, reddish-brown timber of three tropical hardwood species of the genus ''Swietenia'', indigenous to the AmericasBridgewater, Samuel (2012). ''A Natural History of Belize: Inside the Maya Forest''. Austin: Universit ...

, cashews, nutmegs and magnolias, with

bamboo Bamboos are a diverse group of mostly evergreen perennial plant, perennial flowering plants making up the subfamily (biology), subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family, in th ...

s such as '' Bambusa arundinaria'' and '' Melocanna bambusoides''.

Fauna/animals

Despite the centuries of human clearance and exploitation, the forests and grasslands along the river remain a habitat for a variety of wildlife including

tiger The tiger (''Panthera tigris'') is a large Felidae, cat and a member of the genus ''Panthera'' native to Asia. It has a powerful, muscular body with a large head and paws, a long tail and orange fur with black, mostly vertical stripes. It is ...

(''Panthera tigris''), clouded leopard (''Pardofelis nebulosa''),

capped langur The capped langur (''Trachypithecus pileatus'') is a primate species in the family Cercopithecidae native to subtropical and tropical dry forests in northeast India, Bhutan, Bangladesh and Myanmar. It is arboreal and feeds on 43 plant species. ...

(''Semnopithecus pileatus''),

gaur The gaur (''Bos gaurus''; ) is a large bovine native to the Indian Subcontinent and Southeast Asia, and has been listed as Vulnerable species, Vulnerable on the IUCN Red List since 1986. The global population was estimated at a maximum of 21,000 ...

(''Bos gaurus''),

barasingha The barasingha (''Rucervus duvaucelii''), sometimes barasinghe, also known as the swamp deer, is a deer species distributed in the Indian subcontinent. Populations in northern and central India are fragmented, and two isolated populations occu ...

deer (''Cervus duvaucelii''),

sloth bear The sloth bear (''Melursus ursinus''), also known as the Indian bear, is a myrmecophagous bear species native to the Indian subcontinent. It feeds on fruits, ants and termites. It is listed as vulnerable on the IUCN Red List, mainly because of ...

(''Melursus ursinus''),

wild water buffalo The wild water buffalo (''Bubalus arnee''), also called Asian buffalo, Asiatic buffalo and wild buffalo, is a large bovine native to the Indian subcontinent and Southeast Asia. It has been listed as ''Endangered'' in the IUCN Red List since 198 ...

(''Bubalus arnee''), India's largest population of

Asian elephant The Asian elephant (''Elephas maximus''), also known as the Asiatic elephant, is the only living ''Elephas'' species. It is the largest living land animal in Asia and the second largest living Elephantidae, elephantid in the world. It is char ...

s (''Elephas maximus'') and the world's largest population of

Indian rhinoceros The Indian rhinoceros (''Rhinoceros unicornis''), also known as the greater one-horned rhinoceros, great Indian rhinoceros or Indian rhino, is a species of rhinoceros found in the Indian subcontinent. It is the second largest living rhinocer ...

, while

Asian black bear The Asian black bear (''Ursus thibetanus''), also known as the Asiatic black bear, moon bear and white-chested bear, is a medium-sized bear species native to Asia that is largely adapted to an arboreal lifestyle. It is distributed from southeast ...

s live in the higher slopes of the valley sides. Most of these mammals are threatened or endangered species. The Brahmaputra is a natural barrier to the migration of much wildlife and many species, such as the

pygmy hog The pygmy hog (''Porcula salvania'') is a very small and endangered species of pig and the only species in the genus ''Porcula''. Endemic to India, the pygmy hog is a suid native of the alluvial grasslands in the foothills of the Himalayas, at ...

hispid hare The hispid hare (''Caprolagus hispidus''), also known as the Assam rabbit and bristly rabbit, is a species of rabbit native to South Asia. It is the only species in the genus ''Caprolagus''. Named for its bristly fur coat, the hispid hare is a ...

, or the

Malayan sun bear The Malayan sun bear (''Helarctos malayanus malayanus'') is a subspecies of sun bear, occurring in southeast Asia. In 2025, Malayan sun bear along with the Bornean sun bear (''Helarctos malayanus euryspilus''), have been selected to be new campai ...

, pig-tailed macaque, golden langur,

stump-tailed macaque The stump-tailed macaque (''Macaca arctoides''), also called the bear macaque, is a species of macaque native to South Asia and Southeast Asia. In India, it occurs south of the Brahmaputra River, in the northeastern part of the country. Its range ...

, western hoolock gibbon live on one side of the river only. The area is a meeting point of species of Indian and Malayan origin. The endemic mammals of the valley are the pygmy hog and the hispid hare, both of which inhabit the grasslands of the riverbanks. The valley is home to rich bird life with 370 species of which two are endemic, the Manipur bush quail (''Perdicula manipurensis'') and the marsh babbler (''Pellorneum palustre'') and one, the Bengal florican is very rare. Woodland birds like kalij pheasant, great hornbill, rufous necked hornbill, brown hornbill,

Oriental pied hornbill The oriental pied hornbill (''Anthracoceros albirostris'') is an Indo-Malayan pied hornbill, a large canopy-dwelling bird belonging to the family Bucerotidae. Two other common names for this species are Sunda pied hornbill (''convexus'') and Mala ...

, grey hornbill, peacock pheasant and

tragopan ''Tragopan'' is a bird genus in the pheasant family Phasianidae. Member of the genus are commonly called "horned pheasants" because males have two brightly colored, fleshy horns on their head that can be erected during courtship displays. The hab ...

are quite common.

Threats and preservation

This area has been densely populated for centuries and most of the valley has been and still are used for agriculture. Some blocks of natural habitat do remain, however, mainly in national parks the largest of which are Manas, Dibru-Saikhowa and

Kaziranga National Park Kaziranga National Park is a List of national parks of India, national park in the Golaghat district, Golaghat, Sonitpur district, Sonitpur, Biswanath district, Biswanath and Nagaon district, Nagaon districts of the state of Assam, Assam, India. ...

s in India. In Bhutan, these areas are part of Royal Manas National Park.

Protected areas

In 1997, the

World Wildlife Fund The World Wide Fund for Nature (WWF) is a Swiss-based international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the ...

identified twelve protected areas in the ecoregion, with a combined area of approximately 2,560 km², that include 5% of the ecoregion's area.Wikramanayake, Eric; Eric Dinerstein; Colby J. Loucks; et al. (2002). ''Terrestrial Ecoregions of the Indo-Pacific: a Conservation Assessment.'' Island Press;

Washington, DC Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and Federal district of the United States, federal district of the United States. The city is on the Potomac River, across from ...

. pp. 298-301 * Dehing Patkai Landscape, including Dehing Patkai National Park and Dehing Patkai Elephant Reserve * Mehao Wildlife Sanctuary,

(190 km², also includes portions of the Eastern Himalayan broadleaf forests and Himalayan subtropical pine forests) *

Manas National Park Manas National Park is a national park, Project Tiger reserve, and an elephant reserve in Assam, India. Located in the Himalayan foothills, it borders the Royal Manas National Park in Bhutan. The park is known for its rare and endangered ende ...

(560 km²) * Bornadi Wildlife Sanctuary, Assam (90 km²) *

, Assam (320 km²) * Orang National Park, Assam (110 km²) * Laokhowa Wildlife Sanctuary, Assam (170 km²) * Pobitora Wildlife Sanctuary, Assam (80 km²) * Sonai Rupai Wildlife Sanctuary, Assam (160 km²) * Nameri National Park, Assam (90 km²) * Dibru-Saikhowa National Park, Assam (490 km²) * D'Ering Memorial Wildlife Sanctuary, Arunachal Pradesh (190 km²) * Pabha Wildlife Sanctuary, Assam (110 km²)

Vulture breeding

Rani Vulture Breeding Centre was established in 2008 inside Brahmaputra Valley semi-evergreen forests at Rani in Kamprup district with the help of Jatayu Conservation Breeding Centre, Pinjore, which now houses 90

vulture A vulture is a bird of prey that scavenges on carrion. There are 23 extant species of vulture (including condors). Old World vultures include 16 living species native to Europe, Africa, and Asia; New World vultures are restricted to Nort ...

s as of December 2018. 40 million vultures have died in last 20 years.Haryana may host 6-nation vulture meet next Nov.
Times of India, 21 Dec 2018.

References

External links

* *
Geographical ecoregion maps and basic info. {{ecoregions of India Tropical and subtropical moist broadleaf forests Ecoregions of Bhutan Ecoregions of India Biota of Bhutan Biota of India Indomalayan ecoregions Environment of Assam