Ganges - Ecology and Environment

Ecology and Environment

Human development, mostly agriculture, has replaced nearly all of the original natural vegetation of the Ganges basin. More than 95% of the upper Gangetic Plain has been degraded or converted to agriculture or urban areas. Only one large block of relatively intact habitat remains, running along the Himalayan foothills and including Rajaji National Park, Jim Corbett National Park, and Dudhwa National Park. As recently as the 16th and 17th centuries the upper Gangetic Plain harbored impressive populations of wild Asian elephants (Elephas maximus), tigers (Panthera tigris), Indian Rhinoceros (Rhinoceros unicornis), gaurs (Bos gaurus), barasinghas (Rucervus duvaucelii), sloth Bears (Melursus ursinus) and Indian lions. In the 21st century there are few large wild animals, mostly deer, boars, wildcats, and small numbers of wolves, jackals, and foxes. Bengal tigers survive only in the Sundarbans area of the Ganges Delta. Crocodiles and barasingha are also found in the Sundarbans. The Sundarbands freshwater swamp ecoregion, however, is nearly extinct. Threatened mammals in the upper Gangetic Plain include the tiger, elephant, sloth bear, and chousingha (Tetracerus quadricornis).

Fish are found in all the major rivers of the Ganges basin, and are a vital food source for many people. In the Bengal area common fish include featherbacks (Notopteridae family), barbs (Cyprinidae), walking catfish (Clarias batrachus), gouramis (Anabantidae), and milkfish (Chanos chanos). The critically endangered Ganges shark (Glyphis gangeticus) is also found in the river and other places in south Asia.

Many types of birds are found throughout the basin, such as myna, parrots, crows, kites, partridges, and fowls. Ducks and snipes migrate across the Himalayas during the winter, attracted in large numbers to wetland areas. There are no endemic birds in the upper Gangetic Plain. The Great Indian Bustard (Ardeotis nigriceps) and Lesser Florican (Sypheotides indicus) are considered globally threatened.

The natural forest of the upper Gangetic Plain has been so thoroughly eliminated it is difficult to assign a natural vegetation type with certainty. There are a few small patches of forest left, and they suggest that much of the upper plains may have supported a tropical moist deciduous forest with sal (Shorea robusta) as a climax species.

The Ganges River itself supports the mugger crocodile (Crocodylus palustris) and the gharial (Gavialis gangeticus). The river's most famed fauna is the freshwater dolphin Platanista gangetica gangetica, the Ganges River dolphin, recently declared India's national aquatic animal.

A similar situation is found in the lower Gangetic Plain, which includes the lower Brahmaputra River. The lower plains contain more open forests, which tend to be dominated by Bombax ceiba in association with Albizzia procera, Duabanga grandiflora, and Sterculia vilosa. There are early seral forest communities that would eventually become dominated by the climax species sal (Shorea robusta), if forest succession was allowed to proceed. In most places forests fail to reach climax conditions due to human causes. The forests of the lower Gangetic Plain, despite thousands of years of human settlement, remained largely intact until the early 20th century. Today only about 3% of the ecoregion is under natural forest and only one large block, south of Varanasi, remains. There are over forty protected areas in the ecoregion, but over half of these are less than 100 square kilometres (39 sq mi). The fauna of the lower Gangetic Plain is similar to the upper plains, with the addition of a number of other species such as the Smooth-coated Otter (Lutrogale perspicillata) and the Large Indian Civet (Viverra zibetha).