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Eco-221: Lower Gangetic Plains moist deciduous forests

Source: Wikipedia

Lower Gangetic plains moist deciduous forests
Bhawal National Park
Ecoregion territory (in purple)
Ecology
RealmIndomalayan
Biometropical and subtropical moist broadleaf forests
Borders
List
Bird species380+
Mammal species126
Geography
Area254,100 km2 (98,100 sq mi)
Countries
States
Coordinates24°02′N 89°53′E / 24.033°N 89.883°E / 24.033; 89.883
Conservation
Conservation statusCritical/endangered[1]
Protected2.76%

The Lower Gangetic Plains moist deciduous forests is a tropical and subtropical moist broadleaf forests ecoregion of Bangladesh and India. The ecoregion covers an area of 254,100 square kilometres (98,100 sq mi), comprising most of Bangladesh and the Indian states of West Bengal, Bihar and Tripura, and extending into adjacent states of Odisha, Uttar Pradesh and a tiny part of Assam, as well as adjacent western Myanmar.

Geography

The Lower Gangetic Plains moist deciduous forests extends across the alluvial plain of the lower Ganges and Brahmaputra rivers, which form the world's largest river delta. The ecoregion is currently one of the most densely populated regions on earth, and the forests have largely been replaced with intensive agriculture.

The ecoregion is bounded on the east and northeast by montane tropical rain forests; the Mizoram–Manipur–Kachin rain forests covers the Chin Hills and Chittagong Hills to the east, extending into Myanmar and other states of Northeast India, while the Meghalaya subtropical forests covers the Garo-Khasi-Jaintia Hills of Meghalaya and southern Assam, and almost defines the Bangladesh border with Northeast India. To the north, the ecoregion extends to the base of the Himalayas, where it is bounded by the Terai–Duar savanna and grasslands. The upper portion of the Brahmaputra valley in Assam is home to the humid lowland Brahmaputra Valley semi-evergreen forests. To the northwest, the forests are bounded by the Upper Gangetic Plains moist deciduous forests. The dry Chota Nagpur dry deciduous forests lie on the Chota Nagpur Plateau to the southwest. The Sundarbans freshwater swamp forests and Sundarbans mangroves ecoregions lie in the swampy, semi-brackish and brackish southern reaches of the Ganges-Brahmaputra Delta bordering the Bay of Bengal.

The ecoregion is home to several large cities, including Kolkata, Dhaka, Patna, and Chittagong.

Climate

The climate of the ecoregion is tropical and humid. Most of the annual rainfall comes during the southwest monsoon from June to September.

Flora

The natural vegetation is mostly semi-evergreen forest.

The upper canopy is predominantly of deciduous trees, with a lower storey of evergreen trees. Characteristic trees in disturbed forests are Bombax ceiba together with Albizia procera, Duabanga sonneratioides, Cinnamomum cassia, Durio zibethinus, Garcinia mangostana, Artocarpus heterophyllus, Ficus benghalensis, Gnetum gnemon, Mangifera indica, Toona sinensis, Cocos nucifera, Tetrameles nudiflora, Ginkgo biloba, Prunus serrulata, Camphora officinarum, Tsuga dumosa, Ulmus lanceifolia, and Sterculia villosa. As forests mature sal (Shorea robusta) becomes predominant, but most of the remaining forests do not mature to climax stage because of human disturbance. Where annual fires occur frequently during the dry season, fire-hardy trees and shrubs Zizyphus mauritiana, Madhuca latifolia, Aegle marmelos, Butea monosperma, Terminalia tomentosa, Tectona grandis, and Ochna pumila are common.[1]

Riparian forests are typically an Acacia-Dalbergia association, with Acacia catechu, Dalbergia sissoo, Albizia procera, Bombax ceiba, and Sterculia villosa.[1]

Fauna

The ecoregion is home to 126 native mammal species. They include threatened species like the tiger (Panthera tigris), Asian elephant (Elephas maximus), gaur (Bos gaurus), sloth bear (Melursus ursinus), chousingha (Tetracerus quadricornis), smooth-coated otter (Lutrogale perspicillata), and great Indian civet (Viverra zibetha).[1]

The ecoregion is home to 380 species of birds species, including the Bengal florican (Houbaropsis bengalensis), lesser florican (Sypheotides indicus), Pallas's fish-eagle (Haliaeetus leucoryphus), swamp francolin (Francolinus gularis), Indian grey hornbill (Ocyceros birostris), and Oriental pied hornbill (Anthracoceros albirostris).

Conservation

The ecoregion has been densely settled for many centuries, yet much forest remained until the early 20th century. Forest clearance accelerated during the 20th century, and by the end of the century, only 3% of the ecoregion remained in natural forest. Remaining forest areas are mostly small patches, except for one large block of forest south of Varanasi.[2]

In 1997, the World Wildlife Fund identified over 40 protected areas in the ecoregion, with a combined area of about 7010 km², or approximately 3% of the ecoregion's area. Over half of these protected areas were smaller than 100 km²[2]

References

  1. 1 2 3 4 "Lower Gangetic plains moist deciduous forests". Terrestrial Ecoregions. World Wildlife Fund.
  2. 1 2 Wikramanayake, E.; Dinerstein, E.; Loucks, C. J.; et al. (2002). Terrestrial Ecoregions of the Indo-Pacific: a Conservation Assessment. Island Press; Washington, DC. pp. 303