Due to rapid human population growth and associated habitat
loss, a particularly dramatic decline has occurred in the north
and northwest of the Indian sub-continent, in the region commonly
referred to as the Terai. Covering almost 50,000 km2, the
Terai encompasses parts of Nepal and northern India, reaching from
the tall alluvial grasslands along the large tributaries of the Ganges
River to the sal (Shorea robusta) forests on the southern slopes
along the foothills of the Himalayas. This area used to harbour a
large and continuous elephant population, numbering thousands
of individuals. Today, there are only about 900–1500 elephants
left in the entire Terai (Sukumar 2006), distributed mainly among
two wildlife sanctuaries and three national parks in India and one
national park and one wildlife reserve in Nepal.