| Brahmaputra Valley semi-evergreen forests | |
|---|---|
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| Ecology | |
| Realm | Indomalayan realm |
| Biome | tropical and subtropical moist broadleaf forests |
| Borders | |
| Bird species | 370 [1] |
| Mammal species | 122 [1] |
| Geography | |
| Area | 56,700 km2 (21,900 sq mi) |
| Countries | |
| States | |
| Conservation | |
| Protected | 5% [1] |
The Brahmaputra Valley semi-evergreen forests is a tropical moist broadleaf forest ecoregion of Northeastern India, southern Bhutan and adjacent Bangladesh.
The ecoregion covers 56,700 square kilometers (21,900 sq mi) and encompasses the alluvial plain of the upper Brahmaputra River as it moves westward through India's Assam state (with small parts of the ecoregion in the states of Arunachal Pradesh and Nagaland and also south Bhutan and northern Bangladesh). The valley lies between the Himalayas 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. [1]
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The extensive farming has meant that the original semi-evergreen forest now exists only in patches. Typical canopy trees include the evergreen Syzygium, Cinnamomum and Magnoliaceae along with deciduous Terminalia myriocarpa, Terminalia citrina, Terminalia tomentosa , Cinnamomum cassia , Durio zibethinus , Artocarpus heterophyllus , Ficus benghalensis , Gnetum gnemon , Mangifera indica , Toona ciliata , Toona sinensis , Cocos nucifera , Ginkgo biloba , Prunus serrulata , Camphora officinarum , Cathaya argyrophylla , Taiwania cryptomerioides , Cyathea spinulosa , Sassafras tzumu , Davidia involucrata , Metasequoia glyptostroboides , Glyptostrobus pensilis , Castanea mollissima , Quercus myrsinifolia , Quercus acuta , Quercus glauca , Machilus thunbergii , Tetracentron , Tsuga dumosa , Ulmus lanceifolia , Tectona grandis , Larix gmelinii , Larix sibirica , Larix × czekanowskii , Betula dahurica , Betula pendula , Pinus koraiensis , Pinus sibirica , Pinus sylvestris , Picea obovata , Abies sibirica , Quercus acutissima , Quercus mongolica , Prunus padus , Tilia amurensis , Salix babylonica , Acer palmatum , Acer campbellii , Populus tremula , Ulmus davidiana , Ulmus pumila , Pinus pumila , Haloxylon ammodendron , Elaeagnus angustifolia , Tamarix ramosissima , Pinus roxburghii , Pinus hwangshanensis , Juniperus tibetica , Olea europaea subsp. cuspidata , Shorea robusta , Taxus sumatrana , Juglans regia , Alnus nepalensis , Betula alnoides , Betula utilis , Larix griffithii , Picea brachytyla , Prunus sibirica , Tetrameles species. Understory trees and shrubs include the laurels Phoebe, Machilus , and Actinodaphne , Polyalthias, Aphanamixis , and cultivated Mesua ferrea and species of mahogany, cashews, nutmegs and magnolias, with bamboos such as Bambusa arundinaria and Melocanna bambusoides .
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 (Panthera tigris), clouded leopard (Pardofelis nebulosa), capped langur (Semnopithecus pileatus), gaur (Bos gaurus), barasingha deer (Cervus duvaucelii), sloth bear (Melursus ursinus), wild water buffalo (Bubalus arnee), India's largest population of Asian elephants (Elephas maximus) and the world's largest population of Indian rhinoceros, while Asian black bears 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, hispid hare, or the Malayan sun bear, pig-tailed macaque, golden langur, stump-tailed macaque, 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, grey hornbill, peacock pheasant and tragopan are quite common.
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 Parks in India. In Bhutan, these areas are part of Royal Manas National Park.[ citation needed ]
In 1997, the World Wildlife Fund identified twelve protected areas in the ecoregion, with a combined area of approximately 2,560 km2, that include 5% of the ecoregion's area. [2]
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 vultures as of December 2018. 40 million vultures have died in last 20 years. [3]
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The Taiwan subtropical evergreen forests is an ecoregion that covers most of the island of Taiwan, with the exception of the southern tip of the island, which constitutes the South Taiwan monsoon rain forests ecoregion. The island's concentrated steep mountains host a range of forest types, from subtropical forests in the lowlands to temperate and alpine or montane forests.
The Eastern Himalayan broadleaf forests is a temperate broadleaf forest ecoregion found in the middle elevations of the eastern Himalayas, including parts of Nepal, India, Bhutan, Myanmar and China. These forests have an outstanding richness of wildlife.
The Northern Indochina subtropical forests are a subtropical moist broadleaf forest ecoregion of northern Indochina, covering portions of Vietnam, Laos, Thailand, Myanmar, and China's Yunnan Province.
The Mizoram–Manipur–Kachin rain forests is a subtropical moist broadleaf forest ecoregion which occupies the lower hillsides of the mountainous border region joining Bangladesh, China's Yunnan Province, India, and Myanmar. The ecoregion covers an area of 135,600 square kilometres (52,400 sq mi). Located where the biotas of the Indian Subcontinent and the Indochinese Peninsula meet, and in the transition between subtropical and tropical regions of Asia, the Mizoram–Manipur–Kachin rain forests are home to great biodiversity. The WWF rates the ecoregion as "Globally Outstanding" in biological distinctiveness.
The Taiheiyo evergreen forests is a temperate broadleaf forest ecoregion of Japan.
The Western Himalayan broadleaf forests is a temperate broadleaf and mixed forest ecoregion which is found in the middle elevations of the western Himalayas, including parts of Nepal, India, and Pakistan.
The Southern Korea evergreen forests is a temperate broadleaf and mixed forests ecoregion at the southern end of the Korean Peninsula.
The Daba Mountains evergreen forests are a Global 200 endangered ecoregion located on the Daba Mountains in China. The forests are part of temperate broadleaf and mixed forests containing both coniferous and broadleaf trees covering a swath of Central China. Forests here provide a transitional area between evergreen forests to the south and deciduous forests to the north. The Daba Mountains evergreen forests cover areas of northeast Sichuan Province, southern Shaanxi Province, the northern half of Chongqing Municipality, and western Hubei Province.
The Yunnan Plateau subtropical evergreen forests is an endangered ecoregion in southwestern China. These forests once covered the western parts of the Yungui Plateau but have been significantly reduced and replaced with agricultural land uses. The Yunnan evergreen forests and the neighbouring Guizhou Plateau broadleaf and mixed forests are the only two ecoregions in the Palearctic realm to be classified as part of tropical and subtropical moist broadleaf forests biome.
The Guizhou Plateau broadleaf and mixed forests are a subtropical moist broadleaf forest ecoregion in the Yungui Plateau of China. Much of the original forest has been replaced by secondary forests.
The Changjiang Plain evergreen forests ecoregion covers the plain of the Yangtze River (Changjiang) from where it leaves the mountains at the Three Gorges in the west, to the mouth of the Yangtze at the East China Sea. This plain is one of the most densely populated areas on Earth, and most of the original oak and conifer forests have long been converted to agriculture. Extensive wetlands, however, provide habitat for migratory waterfowl and for diverse aquatic species.
The Jiang Nan subtropical evergreen forests ecoregion covers the mountainous divide between the lower Yangtze River and the coastal plain of South China. The region is also a climatic divide between the temperate valleys of the north and the subtropical forests of the south. The region is important for biodiversity and endemic species. The rugged limestone karst hills have been relatively protected from conversion to agriculture, and support specialized plant and animal communities.
The Northern Triangle subtropical forests ecoregion covers remote, mountainous terrain in the far north of Myanmar. Due to the regions isolation it is relatively untouched and unexplored by humans. Over 95% of the ecoregion is covered with closed evergreen forest, and importantly for conservation, these forests exist in large contiguous blocks. As of the late 1990s, 140 mammal species were known to be in the region, and new species, such the Leaf muntjac discovered in 1997, are still being found.
The Baluchistan xeric woodlands ecoregion covers the middle elevations of a series of mountain ranges of western Pakistan and northeastern Afghanistan, reaching 1,200 kilometres (750 mi) from the Arabian Sea in the south to the Hindu Kush Mountains and the Himalayas in the north. The characteristic vegetation is xeric (dry) woodlands of shrubs and herbaceous cover. The region has rich biodiversity but relatively few endemic species.
