RESEARCH STARTER

Sundarbans wetlands

The Sundarbans wetlands are among the largest contiguous tidal mangrove forests in the world, spanning over 2,510 square miles (6,500 square kilometers) across Bangladesh and India. Situated on the Ganges-Brahmaputra-Meghna delta along the Bay of Bengal, this unique ecosystem features a humid tropical climate with significant rainfall concentrated during the monsoon months. The Sundarbans is renowned for its rich biodiversity, supporting numerous species, including the Bengal tiger, Ganges river dolphin, saltwater crocodile, and hundreds of bird and fish species.

The region's mangrove trees, particularly the sundari and gewa species, play critical roles in erosion prevention and provide essential resources for local communities. However, the area faces significant challenges due to human activities such as fishing, logging, and agriculture, as well as climate-related threats like cyclones and rising sea levels. Conservation efforts, including the establishment of the Sundarbans National Park and its designation as a UNESCO World Heritage Site, aim to protect this vital ecosystem. Despite these initiatives, ongoing habitat loss and the impacts of human population pressures continue to pose substantial risks to the Sundarbans' ecological integrity.

Full Article

  • Category: Marine and Oceanic Biomes.
  • Geographic Location: Asia.
  • Summary: Characterized by one of the world’s largest tidal mangrove forests, the Sundarbans wetlands is a biodiversity hotspot under threat from sea-level rise.

The Sundarbans—beautiful forests in Bengali—is among the world’s largest contiguous tidal mangrove forests. The biome covers more than 3,810 square miles (10,000 square kilometers), split between Bangladesh (60 percent) and India (40 percent). The Sundarbans is located on the vast Ganges-Brahmaputra-Meghna alluvial delta on the Bay of Bengal, a lush and extensive low-lying coastal area.

The climate here is humid tropical, with monsoon effects, with an average maximum temperature of 93.2 degrees F (34 degrees C).

Most precipitation occurs in the May-to-October monsoon season, with heavier rain tending to fall in the eastern areas of the biome. Major storms often bring massive inundation, erosion-causing storm surges, and tidal waves.

Biodiversity

The Sundarbans wetlands form a coastal biodiversity hotspot, supporting several mammal species, with such hallmark species as the Ganges river dolphin (Platanista gangetica gangetica); 35 reptile species, including the saltwater crocodile (Crocodylus porosus); and roughly 334 plant species, 120 fish species, 270 bird species, and 42 mammal species.

The mangrove types of sundari (Heritiera fomes) and gewa (Excoecaria agallocha) are the dominant tree species here. The former is an exceptional hardwood used in furniture, flooring, and boat building, and it is a strong erosion preventer in its tidal environment, while the latter is used for more common commercial functions such as making paper pulp and charcoal—but it also has a growing number of medicinal uses.

The vegetation community of the Sundarbans Wetlands biome also includes Avicennia spp., Sonneratia apetala, Bruguiera gymnorhiza, Aegiceras corniculatum, and Rhizophora mucronata. The golpata palm (Nypa fruticans) is distributed throughout the ecosystem; its dense root system, underground stem, trunkless structure, and moderate salt tolerance are extremely well-adapted to this wetland habitat. Dozens of types of grass, reed, and sedge are found here, as well.

The Sundarbans is perhaps most renowned for its population of Bengal tigers (Panthera tigris tigris), thought to be the only tiger population in the world adapted to living within mangrove forests. The presence of large fauna and increasing human population densities in the Sundarbans mean that human-tiger conflicts are an important social issue. An average of 57 people per year were killed by tiger attacks between 1975 and 1984. However, the average death count in the twenty-first century dropped significantly, with unofficial reports indicating between ten and twenty-five deaths per year. One step to help both the tiger and the people has been the establishment of the Sundarbans National Park and Tiger Reserve, a major conservation area that comprises some 1,000 square miles (2,585 square kilometers) in the Indian portion of the biome.

Another mammal that benefits from the sanctuary of the reserve is the muntjac or barking deer (Muntiacus muntjak). Reptiles sheltering here include the northern river terrapin (Batagur baska), olive ridley sea turtle (Lepidochelys olivacea), water monitor (Varanus salvator), saltwater crocodile (Crocodylus porosus), and king cobra (Ophiophagus hannah). Amphibians found either here or in the Bangladesh portion of the Sundarbans include the tree frog (Polypedates maculatus), skipper frog (Euphlyctis cyanophlyctis), and green frog (E. hexadactylus). The Sundarbans wetlands are rife with such crustaceans as fiddler crab (Uca spp.), shrimp (Penaeus monodon, Metapenaeus monoceros), and mangrove mud crab (Scylla serrata). Hundreds of spider species have also been identified here.

Birds flock here by the millions. Nine species of kingfisher, multiple types of sandpipers, many varieties of heron, storks, terns, curlews, and numerous raptor species, including the sea eagle, rank among the most abundant.

Human Impacts

Tens of millions of people live in and not far upstream from the Sundarbans wetlands. Among the leading activities that most impinge upon the biota here are fishing, aquaculture, logging, and agriculture. Despite great exposure to the life-threatening dangers of major cyclones, many people live and work here—sometimes by their actions undermining the very protections against storm surge and flooding that the wetlands and their mangrove forests provide. It is far from a static situation: Cyclone Sidr in 2007 detrimentally affected 30 percent of the Sundarbans, while Cyclone Aila in 2009 destroyed up to 15 percent of the mangrove forest. In May 2020, Cyclone Amphan damaged more than 463 square miles (1,200 square kilometers) of the region’s mangroves. Cyclone Remal caused 38.1% loss in dense vegetation in the Sundarbans in 2024.

Sea-level rise is expected to significantly threaten the flora and fauna of the Sundarbans during this century. Most of the Sundarbans is less than 3 feet (1 meter) above sea level; sea levels are projected to rise by 0.5–1.5 m by the 2050s. A 2016 study published in the journal Climatic Change estimated that by the year 2100, the Sundarbans wetlands may lose between 31 square miles (81 square kilometers) and 538 square miles (1,393 square kilometers) of mangrove area. Additionally, projections indicate a 45 cm rise by the end of the twenty-first century, which could lead to the destruction of approximately 75% of mangrove ecosystems, as indicated in a 2016 study—the consequences would be more severe on the Bangladeshi side of the wetlands.

Conservation Efforts

The ecological and socioeconomic functions of the Sundarbans and the significant threats this ecosystem faces mean that protecting this ecosystem is important. In 2019, the wetlands were named a Wetland of International Importance by the Ramsar Convention, making them the largest protected wetlands region in India.

The Sundarbans is listed as two distinct United Nations Educational, Scientific and Cultural Organization (UNESCO) World Natural Heritage Sites: the Sundarbans National Park in India was inscribed in 1987 and the Sundarbans in Bangladesh in 1997. Remote sensing via satellite shows that, while the various forms of protective status have held down overall habitat loss in the Sundarbans over the past half-century, there has still been significant land-cover conversion, such as from mangrove to open water and barren land and mud flats.

Stepped-up protection measures include augmented patrols and enforcement, more strict permit requirements for the extraction of various products, and restricted extraction at identified key breeding grounds of certain animals. An Integrated Resource Management Plan (IRMP) was prepared in 1998 to sustainably manage the extraction of timber and non-timber products here. However, there is uncertainty whether the IRMP was successful. From 2019 to 2022, the forests and their resources were managed by the Sundarbans Management Project (SMP II). The 2025 State of Conservation Report from the UNESCO World Heritage Centre on the preservation efforts in the Bangladesh part of the Sundarbans confirmed that between 2001 and 2025 there was almost no loss of forest cover. Technologies such as drone-assisted patrols and SMART (Spatial Monitoring and Reporting Tools) have been deployed to strengthen monitoring and law enforcement in this ecosystem.


Bibliography

Banerjee, Anuradha. Environment, Population and Human Settlements of Sundarban Delta. Ashok Kumar Mittal, 1998.

Bhargava, Radhika, and Daniel A. Friess. “Previous Shoreline Dynamics Determine Future Susceptibility to Cyclone Impact in the Sundarban Mangrove Forest.” Frontiers in Marine Science, 11 Mar. 2022, doi:10.3389/fmars.2022.814577. Accessed 5 Aug. 2026.

Ghosh, Sahana. “Sundarban Reserve Forest Now a Wetland of International Importance.” Mongabay-India, 6 Feb. 2019, india.mongabay.com/2019/02/sundarban-reserve-forest-now-a-wetland-of-international-importance/. Accessed 5 Mar. 2026.

Giri, Chandra, et al. “Monitoring Mangrove Forest Dynamics of the Sundarbans in Bangladesh and India Using Multi-Temporal Satellite Data from 1973 to 2000.” Estuarine, Coastal and Shelf Science, vol. 73, 2007.

Iftekhar, M. S., and P. Saenger. “Vegetation Dynamics in the Bangladesh Sundarbans Mangroves: A Review of Forest Inventories.” Wetland Ecology and Management, vol. 16, 2008.

Jabir, Abdullah-Al, et al. “Correlation between Temperature, Sea Level Rise and Land Loss: An Assessment along the Sundarbans Coast.” Journal of King Saud University – Engineering Sciences, 5 Aug. 2021, doi:10.1016/j.jksues.2021.07.012. Accessed 5 Mar. 2026.

Loucks, Colby, et al. “Sea-Level Rise and Tigers: Predicted Impacts to Bangladesh’s Sundarban Mangroves.” Climatic Change, vol. 98, 2010.

Mehtta, Megnaa. “Counting Tigers, Discounting Victims of Tiger Attacks.” The Indian Forum, 30 Oct. 2023, www.theindiaforum.in/environment/counting-tigers-discounting-victims-tiger-attacks. Accessed 5 Mar. 2026.

Mishra, Manoranjan, et al. “Geospatial Analysis of Cyclone Remal’s Impact on the Sundarbans Biosphere Reserve: Insights into Vegetation Loss, Shoreline Changes, and Flooding Dynamics.” Regional Studies in Marine Science, Jan. 2026, p. 104816, doi:10.1016/j.rsma.2026.104816. Accessed 5 Mar. 2026.

Navid Safiullah, Mohammad. “State of Conservation Report on the Decisions of 45 COM 7B.14 the World Heritage Committee on the Sundarbans World Heritage Site.” Ministry of Environment, Forest and Climate Change, Dec. 2025, whc.unesco.org/document/224143. Accessed 5 Mar. 2026.

Payo, Andres, et. al. “Projected Changes in Area of the Sundarban Mangrove Forest in Bangladesh Due to SLR by 2100.” Climatic Change, vol. 132, no. 2, 2016, pp. 279–91, doi:10.1007/s10584-016-1769-z. Accessed 5 Mar. 2026.

Roy, Shouraseni Sen, et al. “Transformation of Coastal Wetlands in the Sundarban Delta (1999–2020).” Environmental Monitoring and Assessment, 24 July 2024, link.springer.com/article/10.1007/s10661-024-12901-x. Accessed 5 Mar. 2026.

“The Sundarbans: A Unique Wilderness of the World.” U.S. Department of Agriculture, 2000, research.fs.usda.gov/treesearch/21939. Accessed 5 Mar. 2026.

“The Sundarbans (Bangladesh); Sundarbans National Park (India).” UNESCO World Heritage Convention, 1999, whc.unesco.org/en/decisions/5700/. Accessed 5 Mar. 2026.

Full Article

  • Category: Marine and Oceanic Biomes.
  • Geographic Location: Asia.
  • Summary: Characterized by one of the world’s largest tidal mangrove forests, the Sundarbans wetlands is a biodiversity hotspot under threat from sea-level rise.

The Sundarbans—beautiful forests in Bengali—is among the world’s largest contiguous tidal mangrove forests. The biome covers more than 3,810 square miles (10,000 square kilometers), split between Bangladesh (60 percent) and India (40 percent). The Sundarbans is located on the vast Ganges-Brahmaputra-Meghna alluvial delta on the Bay of Bengal, a lush and extensive low-lying coastal area.

The climate here is humid tropical, with monsoon effects, with an average maximum temperature of 93.2 degrees F (34 degrees C).

Most precipitation occurs in the May-to-October monsoon season, with heavier rain tending to fall in the eastern areas of the biome. Major storms often bring massive inundation, erosion-causing storm surges, and tidal waves.

Biodiversity

The Sundarbans wetlands form a coastal biodiversity hotspot, supporting several mammal species, with such hallmark species as the Ganges river dolphin (Platanista gangetica gangetica); 35 reptile species, including the saltwater crocodile (Crocodylus porosus); and roughly 334 plant species, 120 fish species, 270 bird species, and 42 mammal species.

The mangrove types of sundari (Heritiera fomes) and gewa (Excoecaria agallocha) are the dominant tree species here. The former is an exceptional hardwood used in furniture, flooring, and boat building, and it is a strong erosion preventer in its tidal environment, while the latter is used for more common commercial functions such as making paper pulp and charcoal—but it also has a growing number of medicinal uses.

The vegetation community of the Sundarbans Wetlands biome also includes Avicennia spp., Sonneratia apetala, Bruguiera gymnorhiza, Aegiceras corniculatum, and Rhizophora mucronata. The golpata palm (Nypa fruticans) is distributed throughout the ecosystem; its dense root system, underground stem, trunkless structure, and moderate salt tolerance are extremely well-adapted to this wetland habitat. Dozens of types of grass, reed, and sedge are found here, as well.

The Sundarbans is perhaps most renowned for its population of Bengal tigers (Panthera tigris tigris), thought to be the only tiger population in the world adapted to living within mangrove forests. The presence of large fauna and increasing human population densities in the Sundarbans mean that human-tiger conflicts are an important social issue. An average of 57 people per year were killed by tiger attacks between 1975 and 1984. However, the average death count in the twenty-first century dropped significantly, with unofficial reports indicating between ten and twenty-five deaths per year. One step to help both the tiger and the people has been the establishment of the Sundarbans National Park and Tiger Reserve, a major conservation area that comprises some 1,000 square miles (2,585 square kilometers) in the Indian portion of the biome.

Another mammal that benefits from the sanctuary of the reserve is the muntjac or barking deer (Muntiacus muntjak). Reptiles sheltering here include the northern river terrapin (Batagur baska), olive ridley sea turtle (Lepidochelys olivacea), water monitor (Varanus salvator), saltwater crocodile (Crocodylus porosus), and king cobra (Ophiophagus hannah). Amphibians found either here or in the Bangladesh portion of the Sundarbans include the tree frog (Polypedates maculatus), skipper frog (Euphlyctis cyanophlyctis), and green frog (E. hexadactylus). The Sundarbans wetlands are rife with such crustaceans as fiddler crab (Uca spp.), shrimp (Penaeus monodon, Metapenaeus monoceros), and mangrove mud crab (Scylla serrata). Hundreds of spider species have also been identified here.

Birds flock here by the millions. Nine species of kingfisher, multiple types of sandpipers, many varieties of heron, storks, terns, curlews, and numerous raptor species, including the sea eagle, rank among the most abundant.

Human Impacts

Tens of millions of people live in and not far upstream from the Sundarbans wetlands. Among the leading activities that most impinge upon the biota here are fishing, aquaculture, logging, and agriculture. Despite great exposure to the life-threatening dangers of major cyclones, many people live and work here—sometimes by their actions undermining the very protections against storm surge and flooding that the wetlands and their mangrove forests provide. It is far from a static situation: Cyclone Sidr in 2007 detrimentally affected 30 percent of the Sundarbans, while Cyclone Aila in 2009 destroyed up to 15 percent of the mangrove forest. In May 2020, Cyclone Amphan damaged more than 463 square miles (1,200 square kilometers) of the region’s mangroves. Cyclone Remal caused 38.1% loss in dense vegetation in the Sundarbans in 2024.

Sea-level rise is expected to significantly threaten the flora and fauna of the Sundarbans during this century. Most of the Sundarbans is less than 3 feet (1 meter) above sea level; sea levels are projected to rise by 0.5–1.5 m by the 2050s. A 2016 study published in the journal Climatic Change estimated that by the year 2100, the Sundarbans wetlands may lose between 31 square miles (81 square kilometers) and 538 square miles (1,393 square kilometers) of mangrove area. Additionally, projections indicate a 45 cm rise by the end of the twenty-first century, which could lead to the destruction of approximately 75% of mangrove ecosystems, as indicated in a 2016 study—the consequences would be more severe on the Bangladeshi side of the wetlands.

Conservation Efforts

The ecological and socioeconomic functions of the Sundarbans and the significant threats this ecosystem faces mean that protecting this ecosystem is important. In 2019, the wetlands were named a Wetland of International Importance by the Ramsar Convention, making them the largest protected wetlands region in India.

The Sundarbans is listed as two distinct United Nations Educational, Scientific and Cultural Organization (UNESCO) World Natural Heritage Sites: the Sundarbans National Park in India was inscribed in 1987 and the Sundarbans in Bangladesh in 1997. Remote sensing via satellite shows that, while the various forms of protective status have held down overall habitat loss in the Sundarbans over the past half-century, there has still been significant land-cover conversion, such as from mangrove to open water and barren land and mud flats.

Stepped-up protection measures include augmented patrols and enforcement, more strict permit requirements for the extraction of various products, and restricted extraction at identified key breeding grounds of certain animals. An Integrated Resource Management Plan (IRMP) was prepared in 1998 to sustainably manage the extraction of timber and non-timber products here. However, there is uncertainty whether the IRMP was successful. From 2019 to 2022, the forests and their resources were managed by the Sundarbans Management Project (SMP II). The 2025 State of Conservation Report from the UNESCO World Heritage Centre on the preservation efforts in the Bangladesh part of the Sundarbans confirmed that between 2001 and 2025 there was almost no loss of forest cover. Technologies such as drone-assisted patrols and SMART (Spatial Monitoring and Reporting Tools) have been deployed to strengthen monitoring and law enforcement in this ecosystem.


Bibliography

Banerjee, Anuradha. Environment, Population and Human Settlements of Sundarban Delta. Ashok Kumar Mittal, 1998.

Bhargava, Radhika, and Daniel A. Friess. “Previous Shoreline Dynamics Determine Future Susceptibility to Cyclone Impact in the Sundarban Mangrove Forest.” Frontiers in Marine Science, 11 Mar. 2022, doi:10.3389/fmars.2022.814577. Accessed 5 Aug. 2026.

Ghosh, Sahana. “Sundarban Reserve Forest Now a Wetland of International Importance.” Mongabay-India, 6 Feb. 2019, india.mongabay.com/2019/02/sundarban-reserve-forest-now-a-wetland-of-international-importance/. Accessed 5 Mar. 2026.

Giri, Chandra, et al. “Monitoring Mangrove Forest Dynamics of the Sundarbans in Bangladesh and India Using Multi-Temporal Satellite Data from 1973 to 2000.” Estuarine, Coastal and Shelf Science, vol. 73, 2007.

Iftekhar, M. S., and P. Saenger. “Vegetation Dynamics in the Bangladesh Sundarbans Mangroves: A Review of Forest Inventories.” Wetland Ecology and Management, vol. 16, 2008.

Jabir, Abdullah-Al, et al. “Correlation between Temperature, Sea Level Rise and Land Loss: An Assessment along the Sundarbans Coast.” Journal of King Saud University – Engineering Sciences, 5 Aug. 2021, doi:10.1016/j.jksues.2021.07.012. Accessed 5 Mar. 2026.

Loucks, Colby, et al. “Sea-Level Rise and Tigers: Predicted Impacts to Bangladesh’s Sundarban Mangroves.” Climatic Change, vol. 98, 2010.

Mehtta, Megnaa. “Counting Tigers, Discounting Victims of Tiger Attacks.” The Indian Forum, 30 Oct. 2023, www.theindiaforum.in/environment/counting-tigers-discounting-victims-tiger-attacks. Accessed 5 Mar. 2026.

Mishra, Manoranjan, et al. “Geospatial Analysis of Cyclone Remal’s Impact on the Sundarbans Biosphere Reserve: Insights into Vegetation Loss, Shoreline Changes, and Flooding Dynamics.” Regional Studies in Marine Science, Jan. 2026, p. 104816, doi:10.1016/j.rsma.2026.104816. Accessed 5 Mar. 2026.

Navid Safiullah, Mohammad. “State of Conservation Report on the Decisions of 45 COM 7B.14 the World Heritage Committee on the Sundarbans World Heritage Site.” Ministry of Environment, Forest and Climate Change, Dec. 2025, whc.unesco.org/document/224143. Accessed 5 Mar. 2026.

Payo, Andres, et. al. “Projected Changes in Area of the Sundarban Mangrove Forest in Bangladesh Due to SLR by 2100.” Climatic Change, vol. 132, no. 2, 2016, pp. 279–91, doi:10.1007/s10584-016-1769-z. Accessed 5 Mar. 2026.

Roy, Shouraseni Sen, et al. “Transformation of Coastal Wetlands in the Sundarban Delta (1999–2020).” Environmental Monitoring and Assessment, 24 July 2024, link.springer.com/article/10.1007/s10661-024-12901-x. Accessed 5 Mar. 2026.

“The Sundarbans: A Unique Wilderness of the World.” U.S. Department of Agriculture, 2000, research.fs.usda.gov/treesearch/21939. Accessed 5 Mar. 2026.

“The Sundarbans (Bangladesh); Sundarbans National Park (India).” UNESCO World Heritage Convention, 1999, whc.unesco.org/en/decisions/5700/. Accessed 5 Mar. 2026.

More Like ThisRelated Articles

Related Articles (5)

Related Articles (5)