The large tracks of grasslands of Manas NP are some of the last remaining examples of Terai grasslands in the Indian sub-continent. These grasslands are the key sites for biodiversity conservation and are not only restricted as unique habitat but also support a wide range of endangered fauna (Lahkar 2008). About 43% area of Manas National Park is cover by grassland habitat.

Major Conspicuous Changes in the Habitat since Inception

 Due to shifting river courses:- Wildlife habitat has been destroyed due to recurrent flood in the floodplains of river Beki. Manas river having changed its course in 2004 during the high flood season. It has resulted into major changes in hydrology and compartmental change of habitat in Manas. An area of about 5 km belt of forest area along the Beki completely washed way in the flood. Usually, during the month of July and August when the monsoon is at its peak, the hilly streams and rivers are in spate. Trees, boulders, etc. are carried down and deposited at various places forming a barrier. These barriers sometimes gradually enlarge and act like partial dams. The courses of streams are diverted with the consequent erosion of banks. Earth movement is sometimes responsible for the change of big rivers course.