The Sundarbans, covering about one million ha in the delta of the rivers Ganga, Brahmaputra and Meghna at the point where it merges with the Bay of Bengal, is the single largest block of tidal halophytic mangrove forest in the world shared between Bangladesh (62%) and India (38%), which supports a large, biodiversity-rich unique ecosystem.
With its array of trees and wildlife the forest is a showpiece of natural history. It is also a center of economic activities, such as extraction of timber, fishing and collection of honey. The area of Sundarban experiences a subtropical monsoonal climate with an annual rainfall of 1600-1800 mm and severe cyclonic storms. Enormous amount of sediments carried by the three rivers contribute to its expansion and dynamics.
Salinity gradients change over a wide range of spatial and temporal scales. Interestingly, the Bangladesh and Indian portion of the forest are listed in the UNESCO world heritage list separately as the Sundarbans, i.e. the “beautiful forest”, and Sundarban National Park respectively, though they are simply parts of the same forest.
The Sundarbans is intersected by a complex network of tidal waterways, mudflats and small islands of salt-tolerant mangrove forests, and presents an excellent example of ongoing ecological processes.
The area is known for its wide range of flora and fauna. The most famous among these are the man-eating Royal Bengal Tigers, but numerous species of birds, spotted deer, crocodiles and snakes also inhabit it. The mangroves have been extensively exploited over centuries for timber, fish and prawns, honey, fodder, or converted for paddy and aquaculture and now it faces the serious challenges for its existence.
Javan rhino, wild buffalo, hog deer, and barking deer are already extinct from the area. While conservation efforts have focused on wildlife, particularly tiger, through creation of several sanctuaries and a biosphere reserve, reduced freshwater inflows are a serious threat as salinity is rising. Heritiera fomes (from which Sundarban derives its name), Nypa fruticans and Phoenix paludosa are declining rapidly. Other threats to biodiversity come from the growing human population, pollution, and a rise in sea level.¨
By Md. Saidur Rahman