Publications
Turning Brackish: Salinity-Driven Mangrove and Fisheries Decline in the Bangladesh Sundarbans.
Reduced freshwater inflow from the Ganges, driven by upstream abstraction and regulation, has intensified salinity intrusion into the Bangladesh Sundarbans, threatening its biodiversity and livelihoods. This study quantifies how salinity exceeds physiological tolerance thresholds for high-value mangrove species like Heritiera fomes (Sundri), causing a 40% decline in suitable habitat while salt-tolerant but lower-value Excoecaria agallocha expands. Analysis of hydrological records, forest cover data, and fisheries statistics from 1996 to 2016 reveals a 54% drop in fish species richness at Mongla market and accelerating ecosystem degradation. Climate projections to 2050 confirm irreversible losses under current trends unless institutional reforms address Ganges water-sharing. The findings underscore the critical need for upstream freshwater management to sustain biodiversity and the livelihoods of 2.7 million dependent communities.
The Relentless Tide of History
Historical analysis reveals that the Sundarbans, initially perceived as a hostile environment by colonial powers, transitioned into a structured conservation and forest administration system between 1862 and 1943. The study highlights how land leases for agriculture and timber extraction were formalized during this period, culminating in the designation of the entire area as a reserved forest. This transformation underscores the intersection of colonial governance and environmental management, providing insights into the early stages of conservation efforts in one of the world's most significant mangrove ecosystems.
Functional composition outweighs taxonomic and functional diversity in maintaining ecosystem properties and processes of mangrove forests
A study on the Sundarbans mangrove forests reveals that functional composition (FC) of leaf area plays a more significant role in maintaining ecosystem properties and processes (MEPP) than species richness or functional diversity. This finding suggests that regionally dominant species with high leaf area and nitrogen content, along with functionally diverse species, are crucial for sustaining mangrove ecosystems as climate change mitigation solutions. Researchers analyzed data from 93 plots across the Sundarbans Reserved Forests in Bangladesh, examining forest inventory, plant traits, and environmental factors. They found that FC positively influenced total biomass, productivity, sediment organic carbon, and nutrient contents, while also mediating the negative impact of sediment salinity on MEPP. The study highlights the importance of prioritizing specific species in conservation efforts to support mangrove ecosystem services.
Climate change, multi-hazards and society: An empirical study on the coastal community of Indian Sundarban
A significant disparity exists in the coping strategies employed by coastal communities in the Indian Sundarbans to mitigate climate change-related multi-hazards. While island households utilize 4–6 adaptation techniques (78%), primarily asset-related, other regions rely on 1–3 methods (56%), often centered around food and finance safeguards. This variation underscores the differential impact of hazards across geographical locations. The study, based on a survey of 850 rural households in four distinct areas—islands, coastal, riverine, and inland—reveals that migration is also a notable tactic in the region. These findings highlight the urgent need for tailored mitigation and adaptation strategies to address the escalating threats posed by climate change in vulnerable coastal regions.
Do the Soil's Physiochemical Properties Fluctuate with Season and Soil Depth in the Ecological Critical Areas (ECA) of Sundarbans, Bangladesh?
Soil physiochemical properties in the Ecological Critical Areas (ECA) of the Sundarbans, Bangladesh, exhibit significant seasonal and depth-related fluctuations. Key parameters such as bulk density (1.05–1.18 g/cm³), pH (7.30–8.54), electrical conductivity (1.05–2.13 ms/cm), and nutrient levels (N: 0.5–0.72 mg/g, P: 0.03–0.06 mg/g, K: 10.5–12.88 mg/g, Na: 16.89–20.53 mg/g) vary across seasons and soil layers, with stock values for available nutrients ranging from 52.5 to 84.96 kg/ha (N), 3.15 to 7.08 kg/ha (P), 1.10 to 1.52 t/ha (K), and 1.77 to 2.42 t/ha (Na). These findings highlight the dynamic nature of ECA soils, critical for aquaculture productivity and dike greening initiatives. The study, conducted in Satkhira district during pre- and post-monsoon seasons, provides actionable insights for sustainable land management in this threatened region.
Livelihood, conflict and tourism: An assessment of livelihood impact in Sundarbans, West Bengal
A significant shift in livelihood patterns is occurring among communities residing near the Sundarbans, the world's largest mangrove forest reserve. This study reveals that while tourism is appreciated, unregulated and irresponsible tourist behavior poses a major threat to the ecosystem's flora and fauna. Additionally, rising water levels and increased salinity are submerging vast areas of the Sundarbans, exacerbating challenges such as tiger conservation and embankment erosion. The research employed primary surveys, secondary data collection, descriptive, and ethnographic methods to analyze community perceptions and livelihood impacts. It underscores the urgent need for a region-specific approach and regional planning to address these multifaceted threats effectively.
Microplastics pollution load in Sundarban delta of Bay of Bengal
A significant microplastics pollution load, exceeding 56 tons immediately after Cyclone Amphan in 2020 and an estimated 4 million tonnes annually from rivers, threatens the Sundarban mangrove forest. This study highlights the severe ecological risks posed by microplastic contamination, including trophic transfer and bioaccumulation, which can degrade natural resources, disrupt livelihoods, and exacerbate poverty. While governments of India and Bangladesh have implemented mitigation policies, urgent joint initiatives are needed to address pollution risks, conserve biodiversity, and promote sustainable development in this UNESCO World Heritage Site.
Significant reduction of carbon stocks and changes of ecosystem service valuation of Indian Sundarban
Over the past four and a half decades, the Sundarbans mangrove ecosystem has experienced a significant decline in both carbon stocks and ecosystem service values (ESVs), with total losses amounting to 3310.79 million USD and 6.31 Tg of carbon, respectively. This deterioration is attributed to natural and anthropogenic pressures, including illegal human encroachment. The study utilized time-series satellite data (1975, 2000, and 2020) alongside the InVEST model to analyze dynamic patterns of carbon sequestration and employed the Getis-Ord Gi* method to identify ESV change hotspots. These findings underscore the urgent need for stricter regulatory measures to protect this critical ecosystem, which is vital for millions of people.
Additive biomass model for Heritiera fomes (Buch.-Hum.) in the Sundarbans Reserved Forest, Bangladesh
Researchers developed a highly accurate, non-destructive additive biomass model for Heritiera fomes, the dominant mangrove species in Bangladesh's Sundarbans Reserved Forest. The model, validated against independent datasets, demonstrated superior efficiency with lower error metrics (AIC, RMSE%, MAE, MPE) compared to existing pan-tropical models. It effectively estimates biomass and carbon stocks by leveraging diameter at breast height (D) for leaves and branches, while combining D and total tree height (H) for stem and bark. This approach ensures precise carbon sequestration assessments, critical for understanding the Sundarbans' ecological role.
Assessment and Attribution of Mangrove Forest Changes in the Indian Sundarbans from 2000 to 2020
Between 2000 and 2020, the Indian Sundarbans lost approximately 110 km² of mangrove forest to erosion within its reserve areas, while gaining about 81 km² through plantation and regeneration in inhabited zones. Despite these gains—primarily outside contiguous mangroves—satellite-derived health indicators (EVI and NDVI) reveal a pronounced deterioration in mangrove condition, especially in sea-facing regions. This decline correlates with rising salinity, temperature increases, and reduced rainfall during pre- and post-monsoon periods. The study, using supervised classification of Landsat and MODIS imagery, also documents shifts toward salt-tolerant species while freshwater-loving genera like Heritiera, Nypa, and Sonneratia decline. These findings underscore the Sundarbans' vulnerability to climate change, threatening its ecological integrity and carbon storage capacity.
Co-benefits of protecting mangroves for biodiversity conservation and carbon storage
Functional distinctiveness of mangrove biodiversity is the strongest predictor of carbon storage, explaining up to 61% of variation in total ecosystem carbon in the Sundarbans Reserved Forest. This study reveals that protecting and restoring mangroves with diverse functional traits can maximize their climate mitigation potential through enhanced blue carbon storage. Researchers analyzed sediment salinity, taxonomic diversity, and functional diversity to assess their influence on above- and belowground plant biomass carbon, sediment organic carbon, and total ecosystem carbon storage. The findings underscore the co-benefits of biodiversity conservation for both local communities and global climate change mitigation efforts.
Ecologies of capture in Bangladesh's Sundarbans
A dramatic surge in banditry and kidnapping in Bangladesh's Sundarbans, the world's largest mangrove forest, is linked to climate change-driven disruptions. This study introduces the concept of an 'ecology of capture' to illustrate how global conservation efforts and new political economies intersect with long-standing practices, creating new forms of expropriation and exploitation. The research examines the complex interplay between climate hot spots, resource control, and criminal predation, highlighting the unintended consequences of conservation interventions in fragile ecosystems.
Livelihoods dependence on mangrove ecosystems: Empirical evidence from the Sundarbans
A substantial relationship between socioeconomic factors and resource extraction from mangrove ecosystems was identified, highlighting the need for policy interventions that promote less-extractive livelihood diversification strategies such as ecotourism to mitigate environmental impact. The study analyzed data from 1188 households across 35 villages in the Sundarbans, using structured interviews and focus group discussions, complemented by logistic regression analysis. This research contributes to a limited body of work on household dependence on mangrove ecosystems in Asia, providing empirical evidence that could inform sustainable livelihood strategies for coastal communities.
Paradigm shift in the management of the Sundarbans mangrove forest of Bangladesh: Issues and challenges
A paradigm shift towards community co-management is essential for the protection and conservation of the Sundarbans mangrove forest, the world's largest continuous mangrove ecosystem. This study synthesizes 240 years of management interventions in Bangladesh, categorizing them into four distinct periods: conversion for agriculture (1780-1875), timber production and theft control (1876-1951), inventory-based management (1952-1992), and integrated co-management with overlapping projects (1993-2020). While local community involvement has become a cornerstone of modern conservation efforts, significant challenges persist, including resource over-exploitation, vegetation changes, habitat degradation, invasive species, poaching, salinity, extreme weather events, uncontrolled tourism, and pollution. These dynamic issues require strategic attention to ensure the long-term sustainability of this globally significant ecosystem.
Insights on aquatic microbiome of the Indian Sundarbans mangrove areas
A first-of-its-kind study reveals how environmental stressors such as salinity, pollution, eutrophication, and land-use changes shape microbial communities in the Indian Sundarbans mangrove areas. Researchers analyzed bacterial and archaeal communities in estuarine water from Matla River and Thakuran River using 16S rRNA gene-based amplicon approaches, finding that halophilic marine bacteria like Flavobacteriaceae and OM1 clade dominate in low-nutrient coastal waters, while hydrocarbon-degrading bacteria such as Oceanospirillaceae and Spongiibacteraceae thrive under higher eutrophic conditions. Rhodobacteracea emerged as a consistently abundant family across both sites. Redundancy analysis showed that total nitrogen and dissolved inorganic nutrients influenced microbial composition in open marine water, whereas salinity and total nitrogen drove changes in island site microbes. This study underscores the complex interplay between anthropogenic pressures and mangrove microbiome dynamics, though it calls for more systematic sampling to fully assess pollution impacts.
Remote Sensing-Based Mapping of Senescent Leaf C:N Ratio in the Sundarbans Reserved Forest Using Machine Learning Techniques
Research demonstrates that remote sensing data, specifically Landsat TM and Landsat 8 imagery, can accurately map the carbon to nitrogen (C:N) ratio of senescent leaves in mangroves, including the Sundarbans Reserved Forest. The study compared four machine learning models—Stochastic Gradient Boosting, Random Forest, Support Vector Machine, and Partial Least Square Regression—and found that SGB, RF, and SVM outperformed PLSR with statistically significant accuracy (p < 0.05). This breakthrough enables the spatial and temporal monitoring of litter quality, a critical factor in soil decomposition and biogeochemical cycles. The findings highlight the potential for integrating remote sensing techniques into ecosystem modeling to better understand mangrove dynamics.
Saving the Sundarbans from development
Development in the Sundarbans must align with ecosystem conservation and livelihood protection to ensure its long-term preservation. This study argues that current development plans risk undermining the region's unique biodiversity, including its endangered Bengal tiger population, and the livelihoods of local communities. Researchers analyzed existing policies and proposed a framework for sustainable development that integrates ecological safeguards with socio-economic needs. By prioritizing conservation in infrastructure projects, such as roads and agriculture, the Sundarbans can maintain its status as a UNESCO World Heritage Site while supporting local populations.
Valuing ecosystem services of Sundarbans Mangrove forest: Approach of choice experiment
Residents of the Sundarbans mangrove forest, Bangladesh, show significant willingness to pay for ecosystem services, with marginal willingness-to-pay (MWTP) values ranging from Tk. 0.015 to Tk. 0.329 across different options, indicating a potential demand despite lower MWTP in some cases. The study used a choice experiment approach, involving focus group discussions and surveys in seven villages, to measure MWTP and compensating surplus (CS) for services like fish, shrimp larvae, crab capture, and fruit/honey collection. Key factors influencing choices included age, income, education, family composition, and occupational status. The findings highlight the economic value of ecosystem services in the Sundarbans, with option 3 yielding the highest surplus (Tk. 0.551), suggesting strong local support for conservation efforts.
Assessing socio-economic vulnerability to climate change-induced disasters: evidence from Sundarban Biosphere Reserve, India
Communities in the Sundarban Biosphere Reserve (SBR), India, face very high socio-economic vulnerability to climate change-induced disasters such as cyclones and storm surges. The study identified Basanti, Gosaba, Kultali, Namkhana, and Patharpratima blocks as particularly vulnerable, while Kakdwip, Sagar, and Hingalganj showed high vulnerability. This finding was derived from a pragmatic analysis combining exposure metrics—like storm surge height, flood inundation, and drainage factors—with sensitivity and adaptation data from a field survey of 570 households. The research highlights that constant exposure to extreme weather events, coupled with weak infrastructure and poverty, hinders socio-economic progress. Recommendations for improvement include stronger infrastructure, early warning systems, disaster monitoring centers, better transport connectivity, and enhanced livelihood opportunities. This approach effectively demonstrates the impact of climate change on coastal communities and suggests adaptive measures to mitigate vulnerabilities.
Combined effects of climate change and sea-level rise project dramatic habitat loss of the globally endangered Bengal tiger in the Bangladesh Sundarbans
By 2070, the combined effects of climate change and sea-level rise will eliminate all suitable habitat for the globally endangered Bengal tiger in the Bangladesh Sundarbans. Using MaxEnt modeling with current distribution data, land-use/land cover, and bioclimatic variables—coupled with two IPCC climate scenarios (RCP6.0 and RCP8.5) and projected sea-level rise—the study predicts dramatic habitat loss. Sea-level rise is expected to have a substantial negative impact on this low-lying mangrove ecosystem. To ensure the long-term survival of the Bengal tiger, the authors recommend expanding terrestrial protected areas, strengthening law enforcement, and raising awareness among local communities.
Creation of Reserved and Protected Forests
By the late 19th century, the Sundarbans' reserved and protected forests had become a significant economic asset, generating annual revenues of Rs. 2,79,408 with minimal expenditure (Rs. 65,251). This transformation was driven by early conservation efforts initiated in 1862 under Dr. Brandis, which evolved into a more structured system by 1873 under Mr. Home and Dr. Schlich. Their approach focused on regulating timber exports while setting size limits for sundri tree felling (3 cubits girth) and establishing royalty rates for sundri wood (½ anna per maund) and firewood (¼ anna per maund). Dr. Schlich's recommendation to place the entire unleased area under Forest Department control proved successful, marking a pivotal shift in forest management that balanced conservation with economic benefits.
Flow Reorganization in an Anthropogenically Modified Tidal Channel Network: An Example From the Southwestern Ganges‐Brahmaputra‐Meghna Delta
A significant flow reorganization has been observed in the anthropogenically modified tidal channel network of the southwestern Ganges-Brahmaputra-Meghna Delta, with the Shibsa channel widening and deepening while the Pussur channel experiences rapid shoaling. This counterintuitive pattern is driven by the Shibsa's capture of a large portion of the Pussur's basin through transverse channels, enhancing its tidal prism despite embankment-driven reductions in basin volume. The study highlights previously unrecognized interactions within interconnected multichannel tidal networks, emphasizing the importance of flow reorganization in response to anthropogenic perturbations.
Forest Grant Rules from 1870-1879
A period of stagnation in the Sundarbans' forest management, intensified by policy declarations and lack of enforcement, marked the period from 1870 to 1879. The Forest Grant Rules during this decade, though applicable across the region, were largely ineffective due to minimal practical implementation. Leases for reclamation were restricted to lands adjacent to existing reclaimed blocks, with terms lasting up to 99 years and revenue exemptions for the first 20 years. This stagnation was exacerbated in 1874 by a policy declaration from Sir Richard Temple, Lieutenant-Governor at the time, following his tour through the Sundarbans. The study, based on historical records, sheds light on the administrative challenges and policy shifts that influenced forest management during this critical period.
Halomonas Rhizobacteria of Avicennia marina of Indian Sundarbans Promote Rice Growth Under Saline and Heavy Metal Stresses Through Exopolysaccharide Production
Researchers discovered that Halomonas rhizobacteria from the Sundarbans' Avicennia marina mangroves significantly promote rice growth under combined saline and arsenic stress conditions. The key mechanism involves the bacteria's production of exopolysaccharides (EPS), which enhances osmotic tolerance and sequesters arsenic, thereby mitigating toxicity. The study demonstrated a positive feedback loop where salt and arsenic stresses trigger EPS production, which in turn improves plant resilience. Through in vivo and in vitro assays, purified EPS was shown to effectively bind salt and arsenic, with characterization via FT-IR and SEM-EDX confirming its substrate-binding properties. Pot experiments further validated that both the bacteria and pure EPS individually enhance rice growth, underscoring EPS's direct role in stress mitigation and plant promotion.
Litterfall production, decomposition and nutrient accumulation in Sundarbans mangrove forests, Bangladesh
A study on the Sundarbans mangrove forests, Bangladesh, reveals that these ecosystems efficiently store and cycle carbon and nitrogen. The research found that annual litterfall production averages 1005.9 ± 7.0 g m−2 yr−1, with leaves being the primary contributor. During decomposition, litterfall loses 20% of its mass in the first 60 days and 50% by the end of 196 days, with no significant difference observed across different positions or sites. The study also highlights that mangroves growing along oligohaline zones show higher nutrient concentrations, indicating their ecological significance. The research analyzed litterfall production, decomposition patterns, and nutrient accumulation using field experiments to understand the role of Sundarbans in carbon and nitrogen cycling.
Seasonal influence of physicochemical parameters on phytoplankton diversity and assemblage pattern in Kailash Khal, a tropical wetland, Sundarbans, India
A year-long study in Kailash Khal, Sundarbans, revealed that phytoplankton diversity and abundance are significantly influenced by seasonal variations in physicochemical parameters. The research identified 36 genera of phytoplankton, with Bacillariophyceae being the most abundant, particularly during the pre-monsoon season (4.32 × 10³ cells l⁻¹). Statistical analysis showed significant seasonal differences in temperature, dissolved oxygen, conductivity, and other water quality parameters (p < 0.05), which correlated with phytoplankton distribution patterns. Margalef richness and Shannon–Wiener diversity indices indicated a moderately rich phytoplankton community, underscoring the wetland's ecological resilience.
The Problem of the Sundarbans
A complex fiscal system in the Sundarbans, previously chaotic, was successfully organized by 1904. The study highlights that unregulated reclamation had proceeded too rapidly, neglecting irrigation considerations critical for the stability of the port channel to Calcutta. It also underscores the significance of tidal spill in maintaining the ecological health of the Reserved Forest, contrasting it with the constraints imposed by embankments elsewhere. The research compares the problems faced by the 24-Parganas Sundarbans with those of Khulna and Bakarganj, suggesting that the former's issues are more intricate.
Using Continuous Change Detection and Classification of Landsat Data to Investigate Long-Term Mangrove Dynamics in the Sundarbans Region
A third of the Sundarbans mangrove forest, the world’s largest contiguous mangrove, shows long-term degradation despite overall stability in its extent. Using a novel Continuous Change Detection and Classification (CCDC) method on 30 years of Landsat data, researchers found that 25% of the area experienced negative greening trends—likely due to die-back in Heritiera fomes—and that 47.6% of areas damaged by Cyclone Sidr in 2007 had not recovered by mid-2018. While the Sundarbans demonstrates resilience to cyclones, climate-driven degradation may erode this over time. The CCDC method, though computationally intensive, offers a powerful tool for global mangrove monitoring by leveraging every available satellite observation, bypassing cloud cover limitations.
Drivers of mangrove ecosystem service change in the Sundarbans of Bangladesh
A significant decline in ecosystem services provided by the Sundarbans mangrove forest, driven by climatic change, rapid environmental shifts, global demand for mangrove products, infrastructure development, and governance failures, has been identified. The study, conducted through secondary data analysis and primary fieldwork across three districts in Bangladesh, reveals that most ecosystem services have deteriorated over the past two decades. Time series analysis and community perceptions highlighted these drivers, emphasizing the urgent need for transformative stewardship to mitigate irreversible environmental impacts.
Social-ecological dynamics of the small scale fisheries in Sundarban Mangrove Forest, Bangladesh
Small-scale fisheries in the Sundarban Mangrove Forest (SMF), a critical ecosystem for Bangladesh, are under severe threat due to mangrove degradation driven by deforestation, illegal logging, and environmental stressors. Despite diversification efforts, artisanal fishers' livelihoods remain intricately linked to the forest's health. The study reveals that these fishers face multiple risks—including tiger attacks, corruption, and natural disasters—which have compelled them to adopt adaptive strategies such as illegal fishing practices, migration, and reliance on women for household tasks. These coping mechanisms, while necessary, further strain the already fragile social-ecological system (SES). The research highlights urgent policy gaps in managing the SMF, emphasizing the need for sustainable resource utilization to protect both the ecosystem and the livelihoods of its dependent communities.
Biomass and net primary productivity of mangrove communities along the Oligohaline zone of Sundarbans, Bangladesh
Mangrove communities in the oligohaline zone of the Sundarbans, Bangladesh, exhibit high biomass and net primary productivity (NPP), with total above-ground biomass (AGB) and below-ground biomass (BGB) estimated at 154.8 and 84.2 Mg∙ha−1, respectively. The study, conducted over one year from March 2016 to April 2017, revealed a mean annual total litterfall of 10.1 Mg∙ha−1∙yr−1 and a total NPP of 21.0 Mg∙ha−1∙yr−1. The research applied biomass equations and the summation method for productivity estimation, highlighting species-specific variations in biomass allocation and significant root biomass. These findings underscore the ecological significance of Sundarbans mangroves, offering critical insights for conservation strategies and understanding their role in mitigating global warming.
Economic Valuation of the Sundarbans Reserved Forest of Bangladesh The Zonal Travel Cost Method
The Sundarbans Reserved Forest (SRF) in Bangladesh, home to the world's largest tidal mangrove ecosystem and rich biodiversity, including endangered species, has been economically valued at approximately 197 million Tk. per year using the zonal travel cost method. This study analyzed responses from 300 visitors over seven days, establishing a direct relationship between recreational value and travel costs. The findings suggest that an entrance fee of 50 Tk. per person could generate around 5,000,000 Tk. annually, sufficient for mangrove management and biodiversity conservation efforts. This approach provides a critical tool for balancing ecotourism development with environmental preservation in this UNESCO-recognized site.
Mangrove Methane Biogeochemistry in the Indian Sundarbans: A Proposed Budget
A comprehensive methane (CH₄) budget for the Sundarbans mangrove ecosystem reveals significant CH₄ production, transport, and atmospheric exchange. Intertidal sediments produce 3547 µmol m⁻³ wet sediment d⁻¹ of CH₄, with 8.2% advectively transported to adjacent estuaries—20 times more than diffusive flux. The study estimates 0.09 Gg yr⁻¹ of CH₄ released from Sundarbans estuaries to the regional atmosphere, while only 2.75% of forest atmospheric CH₄ reaches the upper atmosphere annually. Mean CH₄ mixing ratios over the forest were 2 ppmv, with photo-oxidation rates of 3.25 × 10⁻⁹ mg cm⁻³ d⁻¹. The research also identifies anaerobic CH₄ oxidation in mangrove sediments, contributing to a nuanced understanding of tropical mangrove biogeochemistry.
Spatial and Temporal Changes of Sundarbans Reserve Forest in Bangladesh
From 1973 to 2010, the Sundarbans Reserve Forest (SRF) in Bangladesh experienced minimal overall area loss but significant internal shifts in land cover. Water bodies, mudflats, and barren lands expanded by 0.45%, 19.69%, and 14.81% respectively, while vegetated land declined by 4.01%. This suggests a decline in evergreen vegetation density and canopy closure. Researchers used remote sensing and GIS tools, applying the Normalized Difference Vegetation Index (NDVI) to analyze these changes. The study recommends real-time monitoring systems for future spatial and temporal tracking of SRF's land cover dynamics.
Sundarban mangroves: diversity, ecosystem services and climate change impacts
Climate change poses severe threats to the Sundarbans mangroves, including salinity intrusion, increased cyclones, and erratic rainfall and temperature patterns, which are already disrupting livelihoods and exacerbating social vulnerabilities. This study systematically reviews the biodiversity, ecosystem dynamics, and services of the Sundarbans mangroves in relation to climatic variations, highlighting their critical role in carbon sequestration, sediment trapping, nutrient recycling, and supporting rich biodiversity through detritus-based food webs. The research underscores the urgent need for high-resolution scientific data to identify multidimensional vulnerabilities and integrate conservation strategies with climate change adaptation, including promoting alternative livelihoods. Interdisciplinary approaches are essential to mitigate future climatic disasters and protect the invaluable ecosystem services provided by this unique coastal wetland.
Are we failing to protect threatened mangroves in the Sundarbans world heritage ecosystem?
A critical analysis reveals that the existing protected area network in the Sundarbans, the world's largest mangrove ecosystem, fails to safeguard the most suitable habitats for four globally threatened mangrove species—Heritiera fomes, Excoecaria agallocha, Ceriops decandra, and Xylocarpus mekongensis. The study, the first of its kind, combines habitat suitability analyses and spatial density mapping to demonstrate that H. fomes and X. mekongensis thrive in upstream areas with lower salinity, while E. agallocha and C. decandra prefer mid- to downstream habitats. Historical harvesting has significantly reduced populations of three species, highlighting urgent conservation gaps. The research recommends reconfiguring the protected area network to include these critical habitats, offering a foundation for future spatial conservation planning and more effective protection of this vital ecosystem.
B. Bangladesh
A reactive monitoring mission by UNESCO and IUCN identified the Maitree Super Thermal Power Plant, proposed near the Sundarbans, as a significant threat to the world's largest unbroken mangrove system. The study highlighted four key concerns: air pollution from coal ash, wastewater and waste ash pollution, increased shipping and dredging activities, and cumulative impacts of industrial development infrastructure. The mission recommended cancelling and relocating the power plant project due to its potential adverse effects on the Sundarbans's outstanding universal value.
Investigating patterns of tiger and prey poaching in the Bangladesh Sundarbans: Implications for improved management
Recent research in the Bangladesh Sundarbans reveals alarming poaching patterns threatening tiger survival, with an estimated 6268 snare loops and six instances of Carbofuran-laced baits used to poison tigers. Poachers strategically target areas away from guard posts but near riverbanks, avoiding protected zones. This high intensity—147 snares per 100 km²—likely contributed to a decline in tiger abundance. The study recommends stricter regulation of Carbofuran and the use of remote camera traps to identify poachers. A simple yet effective method for assessing poaching threats, this approach could be replicated globally to guide conservation efforts.
Mapping Long-Term Changes in Mangrove Species Composition and Distribution in the Sundarbans
A 38-year study of the Sundarbans mangrove forest reveals significant shifts in species composition and distribution, driven by climate change and human activities. Heritiera fomes and Excoecaria agallocha declined by nearly 10%, while Ceriops decandra, Sonneratia apetala, and Xylocarpus mekongensis saw substantial increases of 12.9%, 380.4%, and 57.3%, respectively. Using Landsat satellite imagery and maximum likelihood classification techniques, researchers achieved accuracies ranging from 72% to 89% across four time points (1977–2015). These findings underscore the vulnerability of this critical ecosystem—essential for carbon sequestration, coastal protection, and biodiversity—to ongoing environmental pressures. The study highlights the need for adaptive management strategies to sustain mangrove resources amid accelerating degradation.
Projected changes in area of the Sundarban mangrove forest in Bangladesh due to SLR by 2100
Projected sea-level rise by 2100 may result in significantly smaller area losses for the Sundarbans mangrove forest in Bangladesh compared to previous estimates, with potential net losses ranging from 81–178 km² under a low scenario (0.46 m rise) to 583–1393 km² under a high scenario (1.48 m rise). The study used remote sensing, field measurements, geographic information systems, and simulation modeling with the Sea Level Affecting Marshes Model (SLAMM), which was calibrated against observed area losses from 2000 to 2010. Findings suggest that erosion may remain the dominant loss driver under certain scenarios, while inundation due to sea-level rise could become dominant only under the highest projected rises.
Ranging, Activity and Habitat Use by Tigers in the Mangrove Forests of the Sundarban
A tiger population of approximately 76 individuals, with a density of 4.6 tigers per 100 km², was estimated in the Indian Sundarbans using GPS and VHF radio-collars on six tigers (three males and three females). The study revealed that tigers exhibit strong habitat preference for Avicennia-Sonneratia over Phoenix, Ceriops, and barren areas, while avoiding crossing wide water channels (>400 meters), which serve as natural territory boundaries. Tiger activity peaks between 05:00 and 10:00 hours, overlapping with human activity in high-risk zones like Avicennia-Sonneratia and Phoenix habitats along wide channels. The research highlights the vulnerability of tiger movement due to increasing boat traffic and climate-induced sea-level rise, posing a significant threat to population connectivity.
Accumulation of Trace Metals by Mangrove Plants in Indian Sundarban Wetland: Prospects for Phytoremediation
Research identifies Excoecaria agallocha as a highly efficient mangrove species for cadmium (Cd) bioaccumulation, with the highest bioconcentration factor (BCF) of 15.5 among ten studied species in the Indian Sundarbans. The study reveals that Cd and zinc (Zn) are significantly accumulated in E. agallocha's aerial parts, particularly leaves, suggesting its potential as an effective phytoremediation agent. Investigations across two sites analyzed trace metal(loid) concentrations (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Zn) in plant tissues and sediments, highlighting the Sundarbans' unique sediment properties that enhance metal retention. The findings underscore E. agallocha's role as a 'metal trap,' offering promise for mitigating trace metal pollution through phytoremediation strategies.
An annotated checklist of the vascular plants of Sundarban Mangrove Forest of Bangladesh
A comprehensive annotated checklist identifies 528 vascular plant species in the Sundarban Mangrove Forest of Bangladesh, including 24 true mangroves and 70 mangrove associates. The study reveals a rich diversity with 356 genera across 111 families, dominated by Magnoliopsida (373 species) and Liliopsida (131 species). Notable findings include the dominance of Fabaceae (42 species) in Magnoliopsida and Poaceae (42 species) in Liliopsida, alongside a significant presence of economically important species. Eleven threatened species were also recorded, highlighting the ecological importance of this UNESCO World Heritage Site. The research employs taxonomic analysis to document plant life forms, distribution patterns, and conservation status, providing critical data for biodiversity studies.
Antimicrobial activities of actinomycetes isolated from unexplored regions of Sundarbans mangrove ecosystem
Researchers have identified a highly potent actinomycete strain, SMS_SU21, from the Sundarbans mangrove ecosystem, capable of producing antimicrobial compounds effective against a broad range of pathogens, including phytopathogens. This strain demonstrated remarkable antimicrobial activity with a minimum inhibitory concentration (MIC) value of 0.05 mg/ml and significant antioxidant activity (IC50: 0.242 ± 0.33 mg/ml). The bioactive compound responsible for these activities was purified using GC-MS analysis, highlighting the potential of this strain as a source of new broad-spectrum antimicrobial agents. The study involved isolating and screening 54 actinomycetes from unexplored regions of the Sundarbans, followed by polyphasic identification and metabolic profiling to determine their antimicrobial potential.
Bangladesh Sundarbans: Present Status of the Environment and Biota
A significant decline in sediment-laden freshwater discharge through the Bangladesh Sundarbans Mangrove Forests (BSMF) since the Farakka Barrage's operation in 1975 has led to increased polyhaline conditions, threatening the growth and distribution of Heritiera fomes (sundri), a commercially important mangrove. This study reveals that the BSMF has lost approximately 66 km² of forestland, with a decrease in tree cover from 296 plants per hectare in 1959 to 144 by 1996 and a projected further decline to 109 plants per hectare by 2020. The research utilized Landsat satellite data and GIS analysis from 1970s to 2010, demonstrating that reduced freshwater discharge has altered the mangrove ecosystem, favoring less commercially valuable species like Bruguiera sexangula, Excoecaria agallocha, and Sonneratia apetala. The study suggests restoring pre-1975 sediment flow conditions through water sharing agreements and dredging to mitigate salinity and erosion, potentially funding such efforts through carbon trading, given the BSMF's substantial carbon reserve of 56 million metric tons.
Conservation And Conflicts In The Sundarban Biosphere Reserve, India
A critical balance between conservation and local livelihoods emerges as the central finding of a study on the Sundarbans Biosphere Reserve, India's largest mangrove ecosystem and a UNESCO World Heritage Site. The research reveals that while conservation efforts to protect endangered Bengal tigers are crucial for global biodiversity amid climate change threats, they also intensify resource-access struggles for local fishermen in core and buffer areas. This conflict underscores the complex interplay between human activities and environmental protection, challenging traditional conservation strategies and highlighting the need for sustainable solutions that integrate local livelihoods with ecological preservation. The study employs qualitative analysis to examine these tensions, offering insights into the broader dynamics of human-environment relationships in the Sundarbans region.
Diversity and Distribution of Archaea in the Mangrove Sediment of Sundarbans
Archaeal communities in Sundarbans mangrove sediments exhibit distinct shifts influenced by environmental conditions, particularly pollution levels. Analysis of 16S rRNA gene amplicon sequencing data from three sites revealed dominance of Euryarchaeota and Thaumarchaeota (Marine Group I), with haloarchaea prevailing in polluted areas (Godkhali, Bonnie camp) compared to methanogens in the relatively pristine Dhulibhashani. Statistical analysis confirmed these patterns, highlighting the sensitivity of archaeal diversity to anthropogenic stressors. This study underscores the ecological significance of microbial communities in mangrove ecosystems and their role as indicators of environmental health.
The Indian Sundarban Mangrove Forests: History, Utilization, Conservation Strategies and Local Perception
Despite maintaining its vast extent, the Indian Sundarbans mangrove forest has experienced significant changes in health and structure over the past two-and-a-half centuries due to human interference, upstream development, extreme weather events, and climate change effects. This study reveals that while the areal coverage of the mangroves has remained relatively stable recently, their ecological integrity is under threat. Researchers used a multi-temporal and multi-scale approach, combining historical maps and remote sensing data, to trace these changes. The findings underscore the complex interplay between conservation strategies, local livelihoods, and environmental pressures, highlighting the need for adaptive management to protect this critical ecosystem.
Tigers of Sundarbans in India: Is the Population a Separate Conservation Unit?
Sundarbans tigers, though morphologically distinct from other Bengal tiger subspecies, are not genetically separate but should be managed as a unique 'evolutionarily significant unit' (ESU) due to their ecological non-exchangeability. The study analyzed nine microsatellites and 3 kb of mitochondrial DNA from four genes to assess genetic variability, population structure, and connectivity between Sundarbans tigers and mainland Indian populations. Findings revealed that while Sundarbans tigers are not a distinct subspecies, they exhibit stronger genetic differentiation in mitochondrial DNA compared to nuclear DNA, indicating recent divergence within the last 2000 years. The research suggests that historical habitat fragmentation has reduced gene flow, making these tigers ecologically distinct and warranting separate conservation strategies under the adaptive evolutionary conservation (AEC) concept.
True mangrove species of Sundarbans Delta, West Bengal, eastern India
A comprehensive revision of the Sundarbans mangrove species list identifies 24 true mangrove species, belonging to nine families, with Rhizophoraceae exhibiting the highest generic and specific richness. This study resolves long-standing debates about distinguishing true mangroves from minor or associate species by analyzing adaptive morpho-physiological traits suited for tidal-saline environments. The findings highlight the taxonomic diversity and ecological significance of the Sundarbans' mangrove flora, providing a critical framework for understanding its unique biodiversity.
Biological activities and chemical constituents of some mangrove species from Sundarban estuary: An overview
Mangrove species from the Sundarbans, spanning India and Bangladesh, exhibit significant medicinal potential with diverse biological activities. This review highlights seven key species—Ceriops decandra, Xylocarpus granatum, Xylocarpus moluccensis, Excoecaria agallocha, Sarcolobus globosus, Sonneratia caseolaris, and Acanthus ilicifolius—as rich sources of bioactive compounds used in traditional medicine. While these plants are integral to local livelihoods and folk remedies for various ailments, systematic studies on their chemical constituents and activity-structure relationships remain limited. The review synthesizes existing research to underscore the need for further exploration of these species as novel sources of medicinal agents while advocating for their conservation and sustainable utilization.
Cyclone Sidr Impacts on the Sundarbans Floristic Diversity
A severe tropical cyclone, Sidr, struck the Sundarbans in November 2007, causing significant damage to its floristic diversity. The study found that approximately 45% of the Bangladesh portion of this UNESCO World Heritage Site (about 2500 sq. km) was affected, with three key mangrove species—Heritiera fomes (Sundari), Excoecaria agallocha (Gewa), and Sonneratia apetala (Kewra)—showing notable declines in abundance. Remote sensing techniques, including unsupervised classification (ISODATA) and normalized difference vegetation index (NDVI) analysis of Landsat 7 ETM+ images from 2007 to 2010, revealed that post-cyclone regeneration occurred at a faster rate between 2009-2010 compared to 2008-2009. The findings highlight the Sundarbans' resilience but also underscore the temporary loss of diversity following extreme disturbances, which took three years to recover. This study demonstrates the efficiency of remote sensing in assessing and monitoring such ecological impacts.
Ecology of Sundarban, Bangladesh
The Sundarbans, the world's largest mangrove wetland spanning 1 million hectares (60% in Bangladesh and 40% in India), is a biodiversity hotspot with significant ecological roles. This study highlights its critical functions: coastal protection against erosion and tidal waves, fishery resource generation, and provision of forestry products. It supports an extraordinary diversity of flora—35 true mangrove species (out of 50 globally), 334 plant species, and rich faunal diversity, including the endangered Royal Bengal Tiger, wild buffalo, and 25 bird species. The dominant tree species are Sundry (Heritiera fomes, 73%) and Gewa (Excoecaria agallocha, 16%). The research provides a comprehensive assessment of the Sundarbans' ecological structure, emphasizing its global importance as a unique mangrove ecosystem.
Natural resources, livelihoods, and reserve management: a case study from sundarbans mangrove forests, bangladesh
Residents of the Sundarbans mangrove forests, a UNESCO World Heritage and Ramsar site, significantly depend on ecosystem services for both cash income and subsistence. The study reveals that local households generate income by selling products like fish, honey, and nipa palm, while also relying on natural resources for food, fresh water, and timber. However, improved resource management—such as reducing corruption and enforcing better laws—could substantially boost residents' livelihoods without compromising biodiversity conservation. This case study highlights the delicate balance between sustainable development and ecological preservation in one of the world's largest mangrove ecosystems.
Nutrient dynamics in the Sundarbans mangrove estuarine system of Bangladesh under different weather and tidal cycles
Nutrient levels in the Sundarbans mangrove estuarine system of Bangladesh exhibit significant seasonal and tidal variations, with monsoon periods characterized by elevated phosphate, sulfate, and ammonia concentrations alongside reduced dissolved oxygen and salinity. Unlike other areas, the western Sundarbans experiences limited freshwater input during monsoons, which mitigates variability in nutrient dynamics. The study analyzed water samples from six locations across high and low tides during post-monsoon, winter, and monsoon seasons (2010–2011), revealing distinct seasonal patterns in nitrate, phosphate, sulfate, and ammonia levels without consistent tidal fluctuations. These findings advance the understanding of nutrient distribution seasonality and its potential tidal influence, offering critical data for the sustainable management of coastal mangrove ecosystems.
The Range of Prey Size of the Royal Bengal Tiger of Sundarbans
A significant increase in the relative number of prey species consumed by Royal Bengal Tigers in the Sundarbans correlates with increased prey availability, suggesting a positive effect on tiger conservation. The study analyzed 214 tiger scat samples to identify undigested remains, revealing that tigers primarily consume spotted deer, wild boar, rhesus monkeys, and water monitors. While small prey species make up a low proportion of the diet, their importance is highlighted in the context of increased vigilance and habitat conservation efforts.
Assessing the threat of human consumption of tiger prey in the B angladesh S undarbans
A significant portion of households in the Bangladesh Sundarbans, approximately half, consume deer meat annually, with an estimated 11,195 deer being killed for this purpose each year. This consumption is driven by the perceived taste quality of deer meat and is more prevalent among households closer to the forest boundary and those with higher incomes. While most respondents are aware that deer consumption is illegal, a majority view the existing laws as ineffective. The study employed an interview survey to assess the scale and drivers of prey poaching, providing critical insights for designing targeted conservation strategies to mitigate this threat to tiger populations in the Sundarbans.
Role of Zooplankton Diversity in Vibrio cholerae Population Dynamics and in the Incidence of Cholera in the Bangladesh Sundarbans
Research in the Bangladesh Sundarbans reveals that rotifers and cladocerans, alongside copepods, are consistently associated with the presence of pathogenic Vibrio cholerae strains and the incidence of cholera. This finding highlights the role of zooplankton diversity in influencing V. cholerae population dynamics and disease outbreaks. The study analyzed chitinous zooplankton communities across different water bodies to understand their interaction with V. cholerae and cholera cases, uncovering subtle ecological factors that modulate these relationships.
Valuing the Land of Tigers: What Indian Visitors Reveal
Indian visitors to the Sundarbans, a UNESCO World Heritage Site and the world's only mangrove forest inhabited by Royal Bengal Tigers, place significant economic value on its biodiversity. This study reveals that visitors perceive the site not just as a tiger reserve but also as a critical habitat for other species like spotted deer, crocodiles, and snakes, contributing to its ecological importance. The research employs economic valuation techniques to quantify visitor preferences, highlighting the region's role in coastal evolution and conservation challenges posed by human encroachment. Findings underscore the need for balanced conservation efforts to protect both the tiger population and the broader ecosystem, which faces threats from rapid forest cover depletion despite recent conservation successes.
Water salinity investigation in the Sundarbans rivers in Bangladesh
Water salinity intrusion has significantly degraded the quality of rivers in the Sundarbans, Bangladesh, since the diversion of Ganges water at Farakka Barrage in 1975. This study reveals that increased salinity and siltation pose severe threats to mangrove ecosystems, which are vital for coastal protection against storm surges and cyclones. Using a four-year time series dataset from 13 rivers, researchers modeled water salinity to approximate its distribution, providing critical data for decision-making. The findings underscore the urgent need for interdisciplinary management strategies to ensure fresh water supply from the Ganges, thereby safeguarding this unique mangrove forest and its ecological functions.
Community-Based Tourism and Ecotourism Are Potential Means to Facilitate the Conservation of Natural Resources of the Sundarbans – a Theoretical Perspective
Community-based tourism (CBT) and ecotourism hold significant potential to facilitate the conservation of natural resources in the Sundarbans Reserved Forest (SRF), offering multiple benefits while addressing key challenges. These alternative tourism models can generate employment, support local enterprises, and promote environmental awareness through principles like eco-development, moderate development, and informative education. However, their implementation is hindered by gaps in government policy, limited knowledge among locals, poverty, and insufficient institutional support. The study identifies critical factors for success, including community participation, market engagement, capacity building, and collaborative partnerships. It underscores the need for scientific research and coordinated efforts from governments, NGOs, and private sector stakeholders to unlock the full potential of CBT and ecotourism in the Sundarbans, thereby enhancing both conservation efforts and local livelihoods.
Contribution of NTFPs in the Livelihood of Mangrove Forest Dwellers of Sundarban
Non-timber forest products (NTFPs) contribute significantly to the livelihoods of Sundarbans' mangrove forest dwellers, accounting for nearly 79% of their annual income. The study, conducted across four communities in Bally II, Bijoynagar, Dulki, and Hamiltanabad, identified key NTFPs such as firewood, prawn, fish, crab, honey, and bee wax, collected under high-risk conditions from man-eating tigers. It also revealed substantial livelihood vulnerability among the local population, with limited government support. The research highlights the need for sustainable livelihood frameworks that integrate NTFP collection to balance biodiversity conservation and community needs.
Culture independent molecular analysis of bacterial communities in the mangrove sediment of Sundarban, India
A culture-independent molecular analysis of the Sundarbans mangrove sediment revealed a diverse bacterial community, with Gammaproteobacteria being the most abundant group. The study identified at least eight bacterial phyla, including Proteobacteria, Flexibacteria (CFB group), Actinobacteria, Acidobacteria, Chloroflexi, Firmicutes, Planctomycetes, and Gammatimonadates. Notably, some clones showed similarity to bacteria linked to sulfur cycling in saline environments, suggesting their role in maintaining the S-cycle. The analysis also hinted at potential hydrocarbon or oil contamination in the sediment. This research employed 16S rRNA gene libraries and phylogenetic analysis to uncover the microbial diversity in this unique ecosystem, providing insights into its ecological functions and environmental health.
Dynamics of Sundarban estuarine ecosystem: eutrophication induced threat to mangroves
Eutrophication poses a significant threat to the Sundarbans, the world's largest mangrove forest and only tiger habitat. A 2010 study revealed that high nutrient levels, particularly during winter, led to eutrophic conditions (Chlorophyll-a ≥10 μg/L), which negatively impacted phytoplankton biomass and species diversity. The research identified diatoms as the dominant phytoplankton group, with 46 taxa recorded across six groups. Key findings included the presence of bio-indicator species such as Polykrikos schwartzil and Dinophysis norvegica, signaling moderately polluted water quality. The study also highlighted that high salinity levels (21.2PSU) in May favored more resilient phytoplankton species. These insights underscore the deteriorating marine status of the Sundarban estuary, which threatens the ecology of this UNESCO World Heritage Site and raises concerns about the sustainability of its mangroves.
Livelihood and Socio-Economic Aspects of the Sundarbans’ Dependent People: Case Studies on Nalian and Burigoalini Ranges of the Sundarbans
A significant portion of the Sundarbans Reserved Forest (SRF) supports the livelihoods of approximately 3.5 million people, contributing to both local and national economies while also providing coastal protection. This study highlights that the socio-economic conditions of these individuals—who engage in diverse activities such as fishing, salt farming, and resource collection—remain below standard due to seasonal labor dependencies. The research employs primary and secondary data sources to analyze livelihood patterns within the Nalian and Burigoalini Ranges, offering insights into the economic vulnerabilities and resilience strategies of Sundarbans-dependent communities.
Use of an Action‐Selection Framework for Human‐Carnivore Conflict in the Bangladesh Sundarbans
A structured framework for mitigating human-carnivore conflict, particularly in the Bangladesh Sundarbans, has been developed and applied to human-tiger interactions. The approach identifies and ranks potential actions based on their effectiveness and cost-effectiveness, prioritizing tiger-response teams and monitoring of problem tigers as the most impactful strategies. This framework builds on local knowledge, previous management efforts, and research insights, offering a scalable solution for addressing similar conflicts globally. By combining deterrents, education, direct management, and response mechanisms, it aims to reduce retaliatory killings and protect endangered carnivores while balancing economic considerations.
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