The Sundarbans (Bengali: সুন্দরবন, Shundorbôn) is the largest single block of tidal halophytic mangrove forest in the world.[1] The name Sundarban can be literally translated as "beautiful jungle" or "beautiful forest" in the Bengali language (Sundar, "beautiful" and ban, "forest" or "jungle"). The name may have been derived from the Sundari trees that are found in Sundarbans in large numbers. Alternatively, it has been proposed that the name is a corruption of Samudraban (Bengali: সমুদ্রবন Shomudrobôn "Sea Forest") or Chandra-bandhe (name of a primitive tribe). But the generally accepted view is the one associated with Sundari trees.
The forest lies in the vast delta on the Bay of Bengal formed by the super confluence of the Ganges, Brahmaputra and Meghna rivers across Saiyan southern Bangladesh and West Bengal, India. The seasonally-flooded Sundarbans freshwater swamp forests lie inland from the mangrove forests on the coastal fringe. The forest covers 10,000 sq.km. of which about 6,000 are in Bangladesh.[2] It became inscribed as a UNESCO world heritage site in 1997, but while the Bangladeshi and Indian portions constitute the same continuous ecotope, they are separately listed in the UNESCO world heritage list as the Sundarbans and Sundarbans National Park, respectively. The Bangladesh part of the Sundarbans is estimated to be about 4,110 km², of which about 1,700 km² is occupied by waterbodies in the forms of river, canals and creeks of width varying from a few meters to several kilometers.
The Sundarbans is intersected by a complex network of tidal waterways, mudflats and small islands of salt-tolerant mangrove forests. The interconnected network of waterways makes almost every corner of the forest accessible by boat. The area is known for the eponymous Royal Bengal Tiger (Panthera tigris tigris), as well as numerous fauna including species of birds, spotted deer, crocodiles and snakes. The fertile soils of the delta have been subject to intensive human use for centuries, and the ecoregion has been mostly converted to intensive agriculture, with few enclaves of forest remaining. The remaining forests, pain together with the Sundarbans mangroves, are important habitat for the endangered tiger. Additionally, the Sundarbans serves a crucial function as a protective barrier for the millions of inhabitants in and around Kolkata against the floods that result from the cyclones that are a regular occurrence on this coast. Sundarbans have also been enlisted amongst the finalist in the New7Wonders of Nature.
Flora
The Bangladesh mangrove vegetation of the Sundarbans differs greatly from other non-deltaic coastal mangrove forest and upland forests associations. Unlike the former, the Rhizophoraceae are of minor importance. Differences in vegetation have been explained in terms of freshwater and low salinity influences in the Northeast and variations in drainage and siltation. The Sundarbans has been classified as a moist tropical forest demonstrating a whole mosaic of seres, comprising primary colonization on new accretions to more mature beach forests, often conspicuously dominated by Keora (Sonneratia apetala) and tidal forests. Historically three principal vegetation types have been recognized in broad correlation with varying degrees of water salinity, freshwater flushing and physiography and which are represented in the wildlife sanctuaries:
Sundari and Gewa occur prominently throughout the area with discontinuous distribution of Dhundul (Xylocarpus granatum) and Kankra. Among grasses and Palms, Poresia coaractata, Myriostachya wightiana, Imperata cylindrica, Phragmites karka, Nypa fruticans are well distributed. Keora is an indicator species for newly accreted mudbanks and is an important species for wildlife, especially spotted deer (Axis axis). Besides the forest, there are extensive areas of brackish and freshwater marshes, intertidal mudflats, sandflats, sand dunes with typical dune vegetation, open grassland on sandy soils and raised areas supporting a variety of terrestrial shrubs and trees.
Succession is generally defined as the successive occupation of a site by different plant communities.[16] In an accreting mudflats the outer community along the sequence represents the pioneer community which is gradually replaced by the next community representing the seral stages and finally by a climax community typical of the climatic zone.Troup suggested that succession began in the newly accreted land created by fresh deposits of eroded soil.
The pioneer vegetation on these newly accreted site is Sonneratia, followed by Avicennia and Nypa. As the ground is elevated as a result of soil deposition, other trees make their appearance. The most prevalent, though one of the late species to appear, is Excoecaria. As the level of land rises through accretion and the land is only occasionally flooded by tides, Heritiera fomes begins to appear.
Mangrove plants live in hostile environmental conditions such as high salinity, hypoxic (oxygen deficient) waterlogged soil strata, tidal pressures, strong winds and sea waves. To cope up with such a hostile environment mangroves exhibit highly evolved morphological and physiological adaptations to extreme conditions.
The answer is no. Mangroves are facultative halophytes, i.e., the presence of salt in the environment is not necessary for the growth of mangroves and they can grow very well in freshwater. One particular advantage to growing in a salty environment is the lack of competition! Only a limited number of plants have invested evolutionary energy into adapting to intertidal conditions. In the optimum conditions of a tropical rainforest, diversity is great and competition fierce.
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