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.
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.
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.
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.
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.
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