The entire forest landscape along the Indo-Bhutan Boundary is almost contiguous and its biogeography has Indo-Tibetan, Indo-Malayan and Indo-Gangetic influences. The rich biodiversity of this area is attributed to this factor. The alluvial grassland habitat for herbivors like the Great Indian One Horned Rhinoceros is within the administrative boundary of Bodoland Territorial Council.

MANAS NATIONAL PARK

The diverse associations of grassland ecosystems and tree land ecosystems form the mosaic of habitat giving rise to faunal diversity in Manas. The river Dang-Me-Chu becomes the picturesque Manas river before entering the Indian side of Manas National Park (MNP) and drains into the
Brahmaputra after giving rise to Beki river and rejoining with it. This river system with stunning natural view, biodiversity, and geomorphology earned Manas the inscription in the list of World Heritage Sites.
Earlier, an area of 2837 sq. km. landscape along the Indo-Bhutan tract came under Project Tiger Reserve with Manas, then a wild life sanctuary, as a core zone; this was one of the first nine important Project Tiger Reserves in the country.

21 faunal species of Schedule I of the Wildlife (Protection) Act 1972 are supported by the grassland ecosystem of MNP alone. Important mammalian species include Tiger (Panthera tigris tigris), Indian Elephant, One Horned Rhino, Golden Langur, Golden Cat, Hispid Hare, Swamp Deer, Indian Bison, Clouded Leopardetc. According to the latest census, there are 65 tigers, 657 elephants, 200 wild Asiatic Wild Water Buffalo (Bubalus bubalisJ in the MNP.
The last known population of the smallest Wild Pig Pygmy Hog, is present in its last and only home-Manas National Park. The project Tiger area is also a Biosphere Reserve by the same name, Ripu-Chirang Elephant Reserve, and a MIKE (Monitoring of Illegally Killed Elephant) site.