Sundarbans, a mangrove forest in Bangladesh

The Sundarbans, the largest mangrove forest in the world, is one of nature’s most spectacular wonders. Spanning over 10,000 square kilometers, this vast delta lies at the intersection of land and sea, where the mighty Ganges, Brahmaputra, and Meghna rivers converge before flowing into the Bay of Bengal. Approximately 60% of the forest lies in Bangladesh, with the rest in the Indian state of West Bengal. Recognized as a UNESCO World Heritage Site, the Sundarbans is not just a biological treasure trove but also a vital lifeline for millions of people. It is a place where biodiversity, culture, and human resilience intersect in powerful and often precarious ways.

Geographic and Ecological Overview. Sundarbans is a mangrove forest area in the Ganges Delta formed by the confluence of the Ganges, Brahmaputra and Meghna Rivers in the Bay of Bengal. It spans the area from the Hooghly River in India's state of West Bengal to the Baleswar River in Bangladesh's Khulna Division. 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. Spread across 10,000 km2 (3,900 sq mi), it is the world's largest mangrove forest. The islands are also of great economic importance as a storm barrier, shore stabiliser, nutrient and sediment trap, a source of timber and natural resources, and support a wide variety of aquatic, beneficent and terrestrial organisms. They are an excellent example of the ecological processes of monsoon rain flooding, delta formation, tidal influence and plant colonization. Covering 133,010 ha, the area is estimated to comprise about 55% forest land and 45% wetlands in the form of tidal rivers, creeks, canals and vast estuarine mouths of the river. About 66% of the entire mangrove forest area is estimated to occur in Bangladesh, with the remaining 34% in India. Four protected areas in the Sundarbans are enlisted as UNESCO World Heritage Sites, viz. Sundarbans West, Sundarbans South, Sundarbans East in Bangladesh and Sundarbans National Park in India. The Indian Sundarbans were considered endangered in a 2020 assessment under the IUCN Red List of Ecosystems framework. The most abundant tree species are sundri (Heritiera fomes) and gewa (Excoecaria allocate). 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, there has been a consistent pattern of depleted biodiversity or loss of species in the 20th century, with the ecological quality of the forest declining. 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 caused by sea level rise due to effects of 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. Climate change is expected to continue to negatively affect 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. The proposed coal-fired Rampal power station is anticipated to further damage this unique mangrove forest according to a 2016 report by UNESCO. 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 today Khulna, Bangladesh. The first management plan was written for the period 1893–1898. The Sundarban forest lies in the vast delta on the Bay of Bengal formed by the super-confluence of the Hooghly, Padma (both are distributes of Ganges), Brahmaputra and Meghna rivers across southern Bangladesh. The seasonally flooded Sundarbans freshwater swamp forest lies inland from the mangrove forests on the coastal fringe. The forest covers 10,277 km2 (3,968 sq mi) of which about 6,517 km2 (2,516 sq mi) are in Bangladesh. The Indian part of Sundarbans is estimated to be about 4,260 km2 (1,640 sq mi), of which about 1,700 km2 (660 sq mi) is occupied by water bodies in the forms of river, canals and creeks of width varying from a few metres 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 Bengal tiger (Panthera tigris), as well as numerous fauna including species of birds, chital, 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 Kolkata, Khulna and Port of Mongla against the floods that result from the cyclones. It also protects from tsunami and soil erosion for the coastal population.

The Sundarbans is part of the lower Ganges delta, characterized by a network of tidal waterways, mudflats, and small islands. The name "Sundarbans" is thought to derive from the “Sundari” tree (Heritage fomes), which is prevalent throughout the forest and known for its high-quality timber. The region is crisscrossed by a dense lattice of rivers, creeks, and estuaries, many of which are saline or brackish due to the proximity of the Bay of Bengal and tidal influences.The Sundarbans Mangroves correction on the coast forms the seaward fringe of the delta and is the world's largest mangrove ecosystem, with 20,400 square kilometers (7,900 sq mi) of an area covered. The dominant mangrove species Heritiera fomes is locally known as sundri or sundari. Mangrove forests are not home to a great variety of plants. They have a thick canopy, and the undergrowth is mostly seedlings of the mangrove trees.

Besides the sundari, other tree species in the forest include Avicennia, Xylocarpus mekongensis, Xylocarpus granatum, Sonneratia apetala, Bruguiera gymnosperm, Ceriops decandra, Aegiceras corniculatum, Rhizophora mucronata, and Nypa fruticans palms. Twenty-six of the fifty broad mangrove species found in the world grow well in the Sundarbans. The commonly identifiable vegetation types in the dense Sundarbans mangrove forests are salt water mixed forest, mangrove scrub, brackish water mixed forest, littoral forest, wet forest and wet alluvial grass forests. The Bangladesh mangrove vegetation of the Sundarbans differs greatly from other non-delta coastal mangrove forests and upland forests associations. Unlike the former, the Schizophrenia are of minor importance.

The Sundarbans supports about 4 million people directly or indirectly. Key economic activities include:

 Fishing and Aquaculture

 Honey and Wax Collection

 Timber and Fuel Wood Extraction

 Tourism and Handicrafts

Challenges

o Heavy biotic pressure on forests by fringe villagers for fuelwood, collection of crab, honey and tiger prawn seeds, catching fishes as the socio-economic condition of villagers is very poor.

o Natural calamities like cyclones, 'Sidr', 'Aila' etc.

o Global warming and climate change.

o Straying of Tigers & consequent Human-Tiger conflicts.

o Difficult terrain, unstable soil, corrosive nature.

o Lack of inter-agency co-ordination, poor intelligence sharing and lack of awareness.