The
Terai ("moist land") is a belt of marshy
grasslands,
savannas, and
forests at the base of the
Himalaya range in
India,
Nepal, and
Bhutan, from the
Yamuna River in the west to the
Brahmaputra River in the east. Above the Terai belt lies the
Bhabhar, a forested belt of rock, gravel, and soil eroded from the Himalayas, where the water table lies from 5 to 37 meters deep. The Terai zone lies below the Bhabhar, and is composed of alternate layers of clay and sand, with a high water table that creates many springs and
wetlands. The Terai zone is inundated yearly by the
monsoon-swollen rivers of the Himalaya. Below the Terai lies the great
alluvial plain of the
Yamuna,
Ganges,
Brahmaputra, and their tributaries.
The Terai-Duar savanna and grasslands is an ecoregion that stretches across the middle of the Terai belt, from Uttarakhand state through southern Nepal to northern West Bengal. The Terai-Duar savanna and wetlands are a mosaic of tall grasslands, savannas and evergreen and deciduous forests. The grasslands are among the tallest in the world, and are maintained by silt deposited by the yearly monsoon floods. Important grasses include Kans grass (Saccharum spontaneum) and Baruwa grass (Saccharum benghalensis). The ecoregion is home to the endangered Indian Rhinoceros (Rhinoceros unicornis), as well as elephants, tigers, bears, leopards and other wild animals. Much of the ecoregion has been converted to farmland, although Royal Chitwan National Park and Royal Bardia National Park preserve significant sections of habitat, and are home to some of the greatest concentrations of rhinoceros and tiger remaining in South Asia.
In Nepal the Terai is differentiated There is an "outer" and an "inner" Terai.
"Outer Terai" refers to the alluvial, generally forested and often marshy terrain that is transitional between the 1,000 metre Siwalak Range -- the first and lowest range of Himalayan foothills -- and the Gangeatic plain proper. In Nepal, it is conventionally taken to include any extent of Gangeatic Plains proper extending from this transition zone south to the Indian border.
