Sundarbans

Sundarbans (pronounced ) is a mangrove area in the delta formed by the confluence of the Padma, Brahmaputra and Meghna Rivers in the Bay of Bengal. It spans the area from the Baleswar River in Bangladesh's division of Khulna to the Hooghly River in India's state of West Bengal. It comprises closed and open mangrove forests, land used for agricultural purpose, mudflats and barren land, and is intersected by multiple tidal streams and channels. Sundarbans is home to the world's largest area of mangrove forests. Four protected areas in the Sundarbans are enlisted as UNESCO World Heritage Sites, viz. Sundarbans West (Bangladesh), Sundarbans South (Bangladesh), Sundarbans East (Bangladesh) and Sundarbans National Park (India).

Despite these protections, the Indian Sundarbans were considered endangered in a 2020 assessment under the IUCN Red List of Ecosystems framework. The Sundarbans mangrove forest covers an area of about , of which forests in Bangladesh's Khulna Division extend over and in West Bengal, they extend over across the South 24 Parganas and North 24 Parganas districts. The most abundant tree species are sundri (''Heritiera fomes'') and gewa (''Excoecaria agallocha''). The forests provide habitat to 453 fauna wildlife, including 290 bird, 120 fish, 42 mammal, 35 reptile and eight amphibian species. Despite a total ban on all killing or capture of wildlife other than fish and some invertebrates, it appears that there is a consistent pattern of depleted biodiversity or loss of species in the 20th century, and that the ecological quality of the forest is declining.

Despite preservation commitments from both governments, the Sundarbans are under threat from both natural and human-made causes. In 2007, the landfall of Cyclone Sidr damaged around 40% of the Sundarbans. The forest is also suffering from increased salinity due to rising sea levels due to climate change and reduced freshwater supply. In May 2009 Cyclone Aila devastated the Sundarbans with massive casualties. At least 100,000 people were affected by this cyclone. The proposed coal-fired Rampal power station situated north of the Sundarbans at Rampal Upazila of Bagerhat District in Khulna, Bangladesh, is anticipated to further damage this unique mangrove forest according to a 2016 report by UNESCO. Climate change is expected to both continue to negatively effect both natural systems and human populations in the region, resulting in further ecosystem degradation and climate migration. Experts examining the region recommend further focus on mangrove restoration and management and advocating for adaptation of human populations, through processes like managed retreat and investments in resilient infrastructure.

Etymology

The literal meaning of Sundarbans ( bn, সুন্দরবন, Sundôrbôn) is "beautiful forest". Alternatively, it was proposed that the name is a corruption of ''Samudraban'', ''Shomudrobôn'' ("Sea Forest"), or ''Chandra-bandhe'', the name of a tribe. However, the likely origin of the word is ''Sundari'' or ''Sundri'', the local name of the mangrove species ''Heritiera fomes'' abundant in the area.

History

The history of human settlement in the Sundarbans area can be traced back to Mauryan era (4th-2nd century BCE). A ruin of an abandoned city was found in the Baghmara Forest Block that is attributed to Chand Sadagar, a pre-Mauryan semi-historical figure in Bengali folklore. Archaeological excavation at Kapilmuni, Paikgacha Upazilla, north of the Sundarbans in Bangladesh, revealed ruins of urban settlement dating back to the early middle ages. During the Mughal period, forest tracts were leased out by the local rulers for establishing settlements. In 1757, The British East India Company obtained proprietary rights over Sundarbans from the Mughal Emperor Alamgir II and completed mapping the area in 1764. However, systematic forest management started a century later. The first Forest Management Division to have jurisdiction over the Sundarbans was established in 1869. In 1875 a large portion of the mangrove forests was declared as reserved forests under the Indian Forest Act of 1865 (Act VIII of 1865). The remaining portions of the forests were declared a reserve forest the following year and the forest, which was so far administered by the civil administration district, was placed under the control of the Forest Department. A Forest Division, which is the basic forest management and administration unit, was created in 1879 with the headquarters in Khulna, Bangladesh. The first management plan was written for the period 1893–1898.

Geography

The Sundarban forest lies in the vast delta on the Bay of Bengal formed by the super confluence of the Hooghly, Padma (both are distributaries of Ganges), Brahmaputra and Meghna rivers across southern Bangladesh. The seasonally flooded Sundarbans freshwater swamp forests lie inland from the mangrove forests on the coastal fringe. The forest covers of which about are in Bangladesh. The Indian part of Sundarbans is estimated to be about , of which about is occupied by water bodies in the forms of river, canals and creeks of width varying from a few metres to several kilometres.

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 Bengal tiger (''Panthera 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, taken together with the Sundarbans mangroves, are important habitat for the endangered tiger. Additionally, the Mangroves species present in the Sundarban area serve a crucial function as a protective barrier for the millions of inhabitants in and around Khulna and Mongla against the floods that result from the cyclones. It also protects from Tsunami and soil erosion for the coastal population.

Physiography

The mangrove-dominated Ganges Delta – the Sundarbans – is a complex ecosystem comprising one of the three largest single tracts of mangrove forests of the world. The larger part is situated in Bangladesh, a smaller portion of it lies in India. The Indian part of the forest is estimated to be about 40 percent, while the Bangladeshi part is 60 percent. To the south the forest meets the Bay of Bengal; to the east it is bordered by the Baleswar River and to the north there is a sharp interface with intensively cultivated land. The natural drainage in the upstream areas, other than the main river channels, is everywhere impeded by extensive embankments and polders. The Sundarbans was originally measured (about 200 years ago) to be of about . Now it has dwindled into about one-third of its original size. The total land area today is , including exposed sandbars with a total area of ; the remaining water area of encompasses rivers, small streams and canals. Rivers in the Sundarbans are meeting places of salt water and freshwater. Thus, it is a region of transition between the freshwater of the rivers originating from the Ganges and the saline water of the Bay of Bengal.

The Sundarbans along the Bay of Bengal has evolved over the millennia through natural deposition of upstream sediments accompanied by intertidal segregation. The physiography is dominated by deltaic formations that include innumerable drainage lines associated with surface and subaqueous levees, splays and tidal flats. There are also marginal marshes above mean tide level, tidal sandbars and islands with their networks of tidal channels, subaqueous distal bars and proto-delta clays and silt sediments. The Sundarbans' floor varies from above sea level.

Biotic factors here play a significant role in physical coastal evolution, and for wildlife a variety of habitats have developed which include beaches, estuaries, permanent and semi-permanent swamps, tidal flats, tidal creeks, coastal dunes, back dunes and levees. The mangrove vegetation itself assists in the formation of new landmass and the intertidal vegetation plays a significant role in swamp morphology. The activities of mangrove fauna in the intertidal mudflats develop micromorphological