Sundarbans National Park

The average minimum and maximum temperature is 20 °C and 48 °C respectively. Rainfall is heavy with humidity as high as 80% as it is close to the Bay of Bengal. The monsoon lasts from mid-June to mid-September. Prevailing wind is from the north and north-east from October to mid-March and southwest westerlies prevails from mid-March to September. Storms which sometimes develop into cyclones are common during the months of May to October.

Seven main rivers and innumerable watercourses form a network of channels at this estuarine delta. All the rivers have a southward course towards the sea. The eco-geography of this area is totally dependent on the tidal effect of two flow tides and two ebb tides occurring within 24 hours with a tidal range of 3–5 m and up to 8 m[6][7] in normal spring tide, inundating the whole of Sundarban in varying depths. The tidal action deposits silts back on the channels and raising the bed, it forms new islands and creeks contributing to uncertain geomorphology.[8] There is a great natural depression called the Swatch of No Ground in the Bay of Bengal between 21°00' to 21°22' latitude where the depth of water changes suddenly from 20 m to 500 m.[6][9] This mysterious depression pushes back the silts towards south and/or further east to form new islands.

Mangrove trees in Sundarban and a small creek going inside the forest

The Sunderban mudflats[7] are found at the estuary and on the deltaic islands where low velocity of river and tidal current occurs. The flats are exposed in low tides and submerged in high tides, thus being changed morphologically even in one tidal cycle. The interior parts of the mudflats are the right environment for mangroves.

There are a number of mudflats outside the Sundarbans National Park is a mudflat that have the potential to be tourist spots in the Sundarbans. One can visit them and enjoy the beauty of the place during low tide. If one is lucky, one can see sea anemones, horseshoe crab (Nearing extinction)and small octopus.

A tiger looks out from a forest of mangrove date palms.

The coastal active delta of Sundarban at the mouth of Bay of Bengal in Bangladesh, having a complex geomorphologic and hydrological character with climatic hazards, has a vast area of mangrove forests with a variety of flora and diverse fauna in a unique ecosystem. The natural environment and coastal ecosystem of this Biosphere Reserve and World Heritage Site is under threat of physical disaster due to unscientific and excessive human interferences. Conservation and environmental management plan for safeguarding this unique coastal ecology and ecosystem is urgently required.

Sundarban has achieved its name from the Sundari tree. It is the most exquisite variety of tree that are found in this area, a special kind of mangrove tree. It has specialised roots called pneumatophores which emerge above ground and help in gaseous exchange i.e. respiration. During the rainy season when the entire forest is waterlogged, the spikes rising from the ground has their peak in the air and helps in the respiration process.

Salt-water crocodile at Sundarbans

Marsh crocodile

The Sundarbans National Park houses a large number of reptiles as well, including gharials, estuarine crocodiles, chameleons, monitor lizards, turtles, including olive ridley, hawksbill, and green turtles, and snakes, including python, king cobra, rat snake, Russell's viper, dog faced water snake, checkered keelback, red tailed bamboo pit viper, Taipan, Chinese Green viper(Trimeresurus stejnegeri), common krait, etc. Yearly 100-200 people are killed due to snake bites in Sunderbans.

The endangered species that lives within the Sundarbans are royal Bengal tiger, saltwater crocodile, river terrapin, olive ridley turtle, Ganges river dolphin, hawksbill turtle and mangrove horseshoe crab.

The proposed Sundarbans Cetacean Diversity Protected Area,[10] includes the coastal waters off Sundarbans that host critical habitats for endangered cetaceans;[11] resident groups of Bryde's whales, a newly rediscovered critical population of Irrawaddy dolphins,[12] Spinner dolphins, Ganges river dolphins,[13] and Chinese white dolphins. Indo-Pacific finless porpoises, Indo-Pacific bottlenose dolphins, and Pantropical spotted dolphins are also regularly found in this area,[14] while Minke whales and Rough-toothed dolphins and False killer whales are rarer.[15][16]

Though protection exists in the park, there are a few loopholes. The geographical topography with hostile terrain cris-crossed by several rivers and their tributaries, long international border with Bangladesh, fishing trawlers and launches enables poaching and the cutting of wood, affecting the mangrove forests. Lack of staff, infrastructure and lack of funds exacerbate the situation.

The Sunderban Tiger Reserve is located in the South 24 Parganas district of the Indian state of West Bengal, and has a total geographical area of 2585 km², with 1437.4 km² consisting of populated areas and forest covering the remaining 1474 km². The Sunderban landscape is contiguous with the mangrove habitat in Bangladesh.

Sunderban mangroves form part of the largest mangrove system of the Indian subcontinent with a tiger population in a distinct ecological setting. These forests have saltwater crocodiles, estuarine and marine turtles, and a number of bird species. The reserve also contains species of the fishing cat, spotted deer, rhesus monkey, and wild pig.

The Sunderban is isolated with no forest connection to other tiger-occupied mainlands. Due to this, there is heavy biotic pressure for forest resources. On average, 50 metric tonnes of honey and 3 metric tonnes of wax are collected each year by locals under licence from the Indian Forest Service. The habitat is traversed by many narrow tidal channels forming small to large islands. Tigers readily cross these islands and human-tiger interactions are common.

The estimation of tiger population in Sunderban, as a part of the all India tiger estimation using the refined methodology, could not be carried out owing to the unique habitat and obliteration of evidences due to high and low tides. Phase-I data collection has been completed and process is on for tiger estimation using a combination of radio telemetry and pugmark deposition rate from known tigers.

Cyclonic Storm Aila on 24 May 2009 (image by NASA)

Cyclone Aila struck Sunderban on 25 May 2009, causing damage to field camps and fringe villages bordering the reserve. Breaches in the embankments on the village side have caused large scale flooding, leaving lakhs of people marooned in the area. The field camps were under 12 to 15 feet of water for around seven hours, resulting in soil erosion and damage to staff quarters, generators and bamboo pilling. There was a report of a tiger wandering inside an abandoned cattle shed in a village, which was captured and released back in the wild. No tiger death has been reported, apart from the mortality of two spotted deer. Several NGOs have been involved in the relief operation.

The Forest Department of the State has constituted a Committee and has assessed damage of almost Rs. 11150,000. Central assistance amounting to Rs. 10 million under Project Tiger has been provided to the State for restoring the damage done to infrastructure.

Cyclone Amphan made landfall near Sagar Island of South 24 Parganas district on 20 May 2020. Lives have been lost and damage has been meted out to infrastructure.[17] The cyclone damaged "almost the entire nylon fencing" in the forest which prevents the tigers from entering the forest-fringe villages, thereby keeping a check on the man-animal conflict. Besides the fencing, the cyclone also damaged "dozens of forest camp offices, tents, watch towers and staff quarters".[18] The West Bengal Forest Department were initially apprehensive about tigers being harmed or killed by the cyclone but the post cyclone patrolling revealed no dead bodies of the tigers and instead offered glimpses of the animals roaming around in the forest.[19]

The Sunderban Tiger Reserve has several challenges to its future operations. Due to wandering tigers, human-tiger conflict continues to be an issue. Sunderban tigers hunt humans, and it is estimated that over a thousand of the local people have been killed by tigers over the past four decades.[20] An estimation of the number of tigers present in the reserve using the refined method has not yet been completed. A tiger conservation plan is awaited as are constitutions for the State level Steering Committee under the Chairmanship of the Chief Minister and the reserve-specific Tiger Conservation Foundation.