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Spaceborne spectroscopic imaging offers the potential to improve our understanding of biodiversity and ecosystem services, particularly for challenging and rich environments like mangroves. Understanding the signals present in large volumes of high-dimensional spectroscopic observations of vegetation communities requires the characterization of seasonal phenology and response to environmental conditions. This analysis leverages both spectroscopic and phenological information to characterize vegetation communities in the Sundarban riverine mangrove forest of the Ganges–Brahmaputra delta. Parallel analyses of surface reflectance spectra from NASA's EMIT imaging spectrometer and MODIS vegetation abundance time series (2000–2022) reveal the spectroscopic and phenological diversity of the Sundarban mangrove communities. A comparison of spectral and temporal feature spaces rendered with low-order principal components and 3D embeddings from Uniform Manifold Approximation and Projection (UMAP) reveals similar structures with multiple spectral and temporal endmembers and multiple internal amplitude continua for both EMIT reflectance and MODIS Enhanced Vegetation Index (EVI) phenology. The spectral and temporal feature spaces of the Sundarban represent independent observations sharing a common structure that is driven by the physical processes controlling tree canopy spectral properties and their temporal evolution. Spectral and phenological endmembers reside at the peripheries of the mangrove forest with multiple outward gradients in amplitude of reflectance and phenology within the forest. Longitudinal gradients of both phenology and reflectance amplitude coincide with LiDAR-derived gradients in tree canopy height and sub-canopy ground elevation, suggesting the influence of surface hydrology and sediment deposition. RGB composite maps of both linear (PC) and nonlinear (UMAP) 3D feature spaces reveal a strong contrast between the phenological and spectroscopic diversity of the eastern Sundarban and the less diverse western Sundarban. [ABSTRACT FROM AUTHOR]

Spanning across Bangladesh and India, the Sundarban Delta consists of over a thousand islands, the majority of which are protected. These islands are important for the rich biodiversity and unique species found here. However, these islands are also at the forefront of climate change due to the impact of rising sea levels and extreme weather events. Therefore, we analyzed the long-term transformations in the land use land cover (LULC) between 1999 and 2020. We used a variety of geostatistical methods, including optimized hot spots cold spots and join count statistics, to examine the spatial patterns of changes in LULC across the study area. The results of our analysis revealed substantial changes in the spatial patterns of mangroves and pond aquaculture. The changes revealed a distinct north–south demarcation in spatial patterns, in the form of clustering of mangroves in the uninhabited islands located in the south and pond aquaculture clustered in the northern inhabited islands. The loss of area under mangroves was concentrated in the southern edges of the islands, which were most exposed to erosion in the open ocean. Nevertheless, we observed an increase in the area under mangroves in some of the northern riverine islands (17 km2). In the case of pond aquaculture, it was mostly concentrated in inhabited islands in the north. Most of the expansions were concentrated in the Indian part of the delta (631 km2). It is noteworthy that because of effective conservation measures, there was very limited overlap between mangroves and pond aquaculture, denoting the conversion of agricultural land to pond aquaculture instead of mangroves. Thus, the results of our study revealed the importance of local level conservation policies and anthropogenic activities, such as deforestation and local level disturbance like over-extraction of water and pollution, on the changing patterns of LULC across this unique, fragile ecosystem. Future studies may incorporate a finer resolution time series of LULC changes over time and space to enable more detailed analysis. [ABSTRACT FROM AUTHOR]

Floral biochemistry and stress physiology is an underexplored aspect of mangroves, which should be investigated as part of preservation and restoration efforts. A thriving true mangrove tree (Bruguiera gymnorrhiza (L.) Lamk.) and a threatened mangrove-associate species (Heritiera fomes Buch. Ham.) were studied in the Sundarban region of India for seasonal variations in floral odours, non-volatile phytochemicals, antioxidant enzyme activities, and surface water chemistry in surrounding habitat. Both species were found to exhibit significant differences in floral volatilomes, protein contents, antioxidant enzyme activities, total flavonoids, and total phenolic contents between spring and autumn blooms. The bird-pollinated flowers of B. gymnorrhiza also showed considerable seasonal differences in floral anthocyanin and proline contents, indicating vulnerability of the post-anthesis open flowers to environmental factors. Contrarily to previous findings, B. gymnorrhiza floral bouquet appeared to be enriched in various classes of volatiles – dominated by sulphurous compounds in bud stage and terpenoids in open stage. Floral anthocyanins, contributing to the striking colouration of the calyx, were found to comprise cyanidin and delphinidin derivatives. Other glycosides of cyanidin and delphinidin were detected in H. fomes flowers, contributing to visual guides to potential food rewards for pollinating insects. Floral tissue in H. fomes was found to be protected by densely overlapping layers of stellate trichomes containing sesquiterpenoids as phytoprotectants. Comparison of the two floral species suggested that H. fomes flowering is optimized to oligohaline (but not freshwater) vernal conditions; whereas B. gymnorrhiza blooms are adapted for biologically enriched (including abundant herbivores and microbial growth), mesohaline forest habitats. [ABSTRACT FROM AUTHOR]

This study focuses on the successful mixed cultivation of exotic strawberries (Fragaria × ananassa) from the Rosaceae family and dragon fruits (Hylocereus lemairei) in the southern regions of the Sundarbans, West Bengal, India. By leveraging the available agricultural land in the challenging Sundarbans ecosystem, this innovative approach optimizes production through a harmonious mixed cropping system. A decade ago, strawberry farming was predominantly confined to the hill areas of India (Awasthi, 2010)[1]. The agricultural landscape in South 24 Parganas, Sundarbans, is undergoing a transformative shift with the simultaneous cultivation of dragon fruits and strawberries in the same field. This paper explores the evolving trend of this mixed cultivation system, with a specific focus on determining the optimal soil mixture through experimentation in various pots. The identified optimal soil mixture is then implemented in the field after successful trials in different parts of Sundarbans. Additionally, the paper discusses the benefits, challenges, and opportunities associated with this innovative farming model. By showcasing the advantages of integrating these two commercially viable crops and highlighting the refined soil mixture, the study aims to inspire farmers and stakeholders to adopt similar approaches. This collective effort contributes to the sustainability and economic prosperity of the Sundarbans region. [ABSTRACT FROM AUTHOR]

Spaceborne spectroscopic imaging offers the potential to improve our understanding of biodiversity and ecosystem services, particularly for challenging and rich environments like mangroves. Understanding the signals present in large volumes of high-dimensional spectroscopic observations of vegetation communities requires the characterization of seasonal phenology and response to environmental conditions. This analysis leverages both spectroscopic and phenological information to characterize vegetation communities in the Sundarban riverine mangrove forest of the Ganges–Brahmaputra delta. Parallel analyses of surface reflectance spectra from NASA’s EMIT imaging spectrometer and MODIS vegetation abundance time series (2000–2022) reveal the spectroscopic and phenological diversity of the Sundarban mangrove communities. A comparison of spectral and temporal feature spaces rendered with low-order principal components and 3D embeddings from Uniform Manifold Approximation and Projection (UMAP) reveals similar structures with multiple spectral and temporal endmembers and multiple internal amplitude continua for both EMIT reflectance and MODIS Enhanced Vegetation Index (EVI) phenology. The spectral and temporal feature spaces of the Sundarban represent independent observations sharing a common structure that is driven by the physical processes controlling tree canopy spectral properties and their temporal evolution. Spectral and phenological endmembers reside at the peripheries of the mangrove forest with multiple outward gradients in amplitude of reflectance and phenology within the forest. Longitudinal gradients of both phenology and reflectance amplitude coincide with LiDAR-derived gradients in tree canopy height and sub-canopy ground elevation, suggesting the influence of surface hydrology and sediment deposition. RGB composite maps of both linear (PC) and nonlinear (UMAP) 3D feature spaces reveal a strong contrast between the phenological and spectroscopic diversity of the eastern Sundarban and the less diverse western Sundarban.

Sundarban is a designated world heritage with world’s largest contiguous mangrove forest cover, shared by India and Bangladesh. The Indian part is divided into two morphological units: reclaimed section and non-reclaimed mangrove forests. Here alarming changes are reported in light of erratic monsoons, increasing sea levels, salinity, frequent cyclones and coastal flooding, vanishing islands, and socio-economic crisis; leading to growing numbers of ecological refugees. It is one of the most cyclone prone areas in the world. Though there are piecemeal efforts in tackling the menace of cyclone, a holistic cyclone preparedness plan with bottom-up approach is still missing. This lacuna was glaringly highlighted during cyclone Amphan on May 20, 2020, when the state was reeling under the COVID-19 pandemic. To minimize the loopholes in the existing cyclone mitigation practices, the paper tries to prepare a process prototype by involving (a) Occurrence-Resistance-Resilience Analysis and (b) Preparedness-Risk Reduction-Capacity Assessment: encompassing physical and socio-economic parameters. For the first part, vulnerable zone identification through data mining of cyclone occurrence and identification of eroding and stable sections; analysing land use change; studying hydrographic and hydrologic condition affecting the embankment stability; and scrutinising the socio-economic condition and infrastructural amenities present needs to be conducted. The second part entails devising effective management strategies through the following: upgradation of disaster warning system; optimising the location of cyclone shelters and relief distribution centres; efficient relief distribution; and viability checking of insurance cover. This proactive approach reflecting the ground reality would be beneficial for formulating an effective Cyclone Preparedness Plan with a participatory approach. [ABSTRACT FROM AUTHOR]

Climatic disasters and ecological threats lead to migrations of people with transitions in livelihood as displaced communities. Climatic changes and demographic pressures are harshly hampering the ecological balance of the Sundarbans delta region. Western Indian Ocean region's industrial spaces and town economies are alternatives of livelihood for migrants from Sundarbans delta. Historically, the two littorals and hinterland of Arabian Sea and Bay of Bengal of the Indian Ocean remain connected through trade networks. The Colonial State connected these two hinterlands of South Asia through railway networks. Since the late nineteenth century migrations within the regions for livelihood increased. With the twenty-first century the severity of the migration increased because of climatic change. In this research, I investigated the patterns of migration from the Sundarbans delta to the Western Indian Ocean region hinterland city of 'Aurangabad.' This empirical study situates the transitions and impacts on livelihood fragility of the communities displaced. [ABSTRACT FROM AUTHOR]

To evaluate the growth performance of 3495 Black Bengal kids from Jatirampur village of Sunderban area of South 24 Parganas, West Bengal, the data were collected for a period of 15 years (2008-2022) to ascertain the effect of various environmental factors on growth traits and their genetic control over growth performance. Least-squares analysis of variance was applied to determine the effect of nongenetic factors on different growth traits of kids. The heritability of growth traits was estimated by the paternal half-sib method and animal model. The overall least-squares means for weights at birth, 3-, 6-, 9- and 12-months of age were 1.19±0.004, 5.44 ± 0.01, 7.74 ± 0.01, 10.68±0.01 and 13.37 ± 0.01 kg., respectively. The study revealed the periods of birth had a significant (P<0.01) effect on all the growth traits under the study. The kids born in different seasons showed significant variation in body weights recorded in various intervals except in 3rd month. Similarly, a significant effect was shown by the sex of kids on the 3-month body weight of kids. Parity of dam and type of birth showed significant (P<0.05) effects on all traits except the birth weight of kids. Kids born from does of third or later parities had significantly (P<0.05) higher body weights than kids born from does of earlier parities. Single-born kids exhibited significantly (P<0.01) higher body weights at all ages except weight at birth than kids born as twins or triplets. The study also revealed that estimates of heritabilities for all growth traits were low in magnitude, ranging from 0.04 to 0.48, indicating the scope of slow to moderate genetic progress of these traits through selection under the prevalent managemental condition at the region. [ABSTRACT FROM AUTHOR]

A detailed study on potential sources, variation, and environmental effects of the rainwater ions was carried out at Lothian Island, Sundarban mangrove forest, India, during the southwest monsoon (June–September) in 2019. On an event basis, the maximum rainwater precipitation was observed 17.65 mm Day −1 and a minimum of 1.02 mm Day −1. The maximum amount of total precipitation was recorded in the month of July (237 mm). The volume weighted mean (VWM) concentration shows that the total ionic composition was 93.7 μeq L−1, whereas the percentage contribution of the total ionic concentration is found to be 45.97% to anions and 54.02% to the cations. Temporal variation was observed between early (June- July) and late monsoon (August—September), which shows a high concentration of major ions in early monsoon and low concentration in late monsoon due to the washout of atmospheric particles with the frequent and increasing precipitation. The pH values of the 78% samples show neutral pH and neutralization factors (NF) followed a sequence of NFCa ˃NFMg ˃ NFNH4 with factors of 0.77, 0.34, and 0.14 indicating Ca2+ was the most potential species to balance the acidic ions (NO3−, SO42−) over the study area. Source apportionment study indicates the significant influence of marine actions (long-range transport by monsoonal wind from marine origin, Sea spray, salty soil profile of mangrove) as the major source of ions over Sundarban. The rate of nutrient wet deposition in the form of rainwater was estimated and average monsoonal nitrogen flux was observed 0.87 kg ha−1where NO3 contributes the most (0.60 kg ha−1). N and P deposition flux also showed a simultaneous pattern with the seasonal nutrient concentration of surrounding river water, which may be an indication of a possible contribution of atmospheric wet deposition in the spike of monsoonal nutrient concentration in river water. [ABSTRACT FROM AUTHOR]

Coastal areas play an important role in the global food and economic system, but are vulnerable to a number of coastal hazards such as cyclones and storm surges. The Sundarban Biosphere Reserve (SBR) is located on the east coast of India and has a rich diversity of aquatic and terrestrial flora and fauna. The region is frequently affected by coastal hazards such as cyclones and storm surges. The objective of this study is to investigate the impact of Super Cyclone Amphan on land use land cover (LULC) in SBR. For this purpose, the land use land cover (LULC) map of the study area before and after the cyclone was first constructed using four machine learning algorithms: Support Vector Machine (SVM), Spectral Angle Mapper and Maximum Likelihood Classifier. In addition, the accuracy of these methods was evaluated using the confusion matrix. The result shows that the SVM basis provides better accuracy than the other methods. After evaluating the accuracy, the detection of changes in the LULC was analysed. The result shows that forest cover in the region decreased significantly (about 38.8%) due to super cyclone Amphan. In addition, agricultural land, swamps, sandbanks and beaches increased by 49.51%, 39.57%, 17.40% and 6.93% respectively. The findings of this study can be used by local and state disaster management authorities to prepare the effective disaster management plans for the region. [ABSTRACT FROM AUTHOR]

This study was conducted among communities surrounding the Sundarban mangrove forest in Bangladesh with the aim of assessing farmers' participation in agroforestry systems, as well as the opportunities it provides for enhancing sustainable and resilient livelihoods. However, field work was conducted between July 2014 and July 2015 to collect data from 120 respondents who were selected using a multistage sampling technique in four sub-districts (Debhata, Tala, Kalaroa and Kaliganj) in Satkhira, Bangladesh. The results showed that almost 100% of the respondents practiced homestead agroforestry traditionally and more than 56% practiced aquasilviculture. Besides, majority of the farmers (40%) practiced boundary plantation, 31% practiced alley cropping and the rest (29%) practiced random and mixed plantations. Farmers' reported improved opportunities for livelihood diversification by working with agroforestry as of possessing benefits from trees, fruits, medicinal plants, fuel wood and fish as well as opportunities for the rearing of livestock and the cultivation of food crops. The results also showed that these livelihood activities resulted in an enhanced ability of respondents to construct and repair housing (physical capital), purchase land (natural capital), save money (economic capital), fund children's education (human capital) among others. In all, these results suggest that agroforestry is a sustainable alternative livelihood option which provides opportunities for reduced dependency on protected forests, in addition to increased potential for livelihood diversification and ability to cope with climate change impacts and other change drivers. [ABSTRACT FROM AUTHOR]

Halotolerant plant growth promoting rhizobacteria (PGPR) are beneficial microorganisms utilized to mitigate the biotic and abiotic stresses in plants. The areas of Sundarban mangroves of West Bengal, India have been reported to be rich in halotolerant microflora, yet major area remains unexplored. The present study, therefore, aims to map down the region-specific native microbial community potent of salt tolerance, plant growth promoting (PGP) activity and antagonistic activity against fungal pathogens. Bacterial samples were isolated from the saline soil of the Sundarban mangroves. A total of 156 bacterial samples were isolated and 20 were screened for their salt tolerance potential. These isolates were characterised using morphological, biochemical, and molecular approaches. Based on 16s rRNA sequencing, they were classified into 4 different genera, including Arthrobacter sp. (01 isolate), Pseudomonas plecoglossicida (01 isolate), Kocuria rosea (01 isolate), and Bacillus (17 isolates). The halotolerant isolates which possessed plant growth promoting traits including phosphate, and zinc solubilization, indole acetic acid production, siderophore, and ammonia generation were selected. Further, the effect of two halotolerant isolates GN-5 and JR-12 which showed most prominent PGP activities was evaluated in pea plant under high salinity conditions. The isolates improved survival by promoting germination (36 to 43%) and root-shoot growth and weight of pea plant in comparison to non-inoculated control plants. In a subsequent dual culture confrontation experiment, both these halo-tolerant isolates showed antagonistic activities against the aggressive root rot diseasecausing Macrophomina phaseolina (Tassi) Goid NAIMCC-F-02902. The identified isolates could be used as potential bioagents for saline soils, with potential antagonistic effect on root rot disease. However, further studies at the physiological and molecular level would help to delineate a detail mechanistic understanding of broad-spectrum defence against salinity and potential biotic pathogen. [ABSTRACT FROM AUTHOR]

Abstract Rapid impact assessment of cyclones on coastal ecosystems is critical for timely rescue and rehabilitation operations in highly human‐dominated landscapes. Such assessments should also include damage assessments of vegetation for restoration planning in impacted natural landscapes. Our objective is to develop a remote sensing‐based approach combining satellite data derived from optical (Sentinel‐2), radar (Sentinel‐1), and LiDAR (Global Ecosystem Dynamics Investigation) platforms for rapid assessment of post‐cyclone inundation in non‐forested areas and vegetation damage in a primarily forested ecosystem. We apply this multi‐scalar approach for assessing damages caused by the cyclone Amphan that hit coastal India and Bangladesh in May 2020, severely flooding several districts in the two countries, and causing destruction to the Sundarban mangrove forests. Our analysis shows that at least 6821 sq. km. land across the 39 study districts was inundated even after 10 days after the cyclone. We further calculated the change in forest greenness as the difference in normalized difference vegetation index (NDVI) pre‐ and post‐cyclone. Our findings indicate a

Effective mitigation and adaptation methods are critical for addressing multi-hazards in various parts of the world as a result of changing climate occurrences. Basically, coastal areas around the world have been proven to be particularly sensitive and at risk as a result of recent climate change, forcing people to relocate in order to survive. In the previous 2–3 years, cyclones such as Fani, Bulbul, Amphan, and Yass have wreaked havoc on eastern India's coastal region. The aim of this study is to look into the coastal population of Indian Sundarban's perceptions of hazards and their solutions for dealing with the growing threat of hazards. To measure perceptions of multi-hazard impact, a survey of 850 rural households was conducted in four different geographical regions (i.e. island, coastal, riverine, and inland). Several forms of coping techniques have been discovered, and the results differ from one geographical place to the next, demonstrating the different impact of risks in the studied area. It is obvious from the analysis that, with the exception of island households, other areas use a very limited number of adaptation mechanisms. When it comes to the amount of coping strategies used, it has been discovered that most inhabitants outside of islands use 1–3 techniques (nearly 56%) using food and finance as safeguard, but island dwellers use 4–6 strategies (nearly 78%) in form of asset related issues. Reducing the amount of food consumed, obtaining financing from various organizations, and migrating are some of the primary tactics used in the study region to combat the negative effects of climate change-related multi-hazards.

Mangrove forests are considered an important component of the coastal ecosystem. Despite the immense ecological and economic services provided by mangroves, their habitable area has been shrinking at an alarming rate throughout the world. In such circumstances, mapping of mangrove patches is necessary for the proper management of such a fragile but highly productive ecosystem. Most remote sensing-based mapping is limited to analysis of their spectral properties only. These approaches not only fail to improve the classification accuracy but are also unable to delineate small patches of mangroves which are equally important from a conservation perspective. The present study is carried out in coastal West Bengal, India, where land use/covers are intermingled with different types of mangrove and nonmangroves vegetations, which is difficult to separate. In this study, we have combined seven spectral indices along with Landsat-8 OLI spectral bands to delineate mangrove patches. Classified maps using eleven-layer combinations were analyzed by Jefferies-Matusita (JM) Distance separability and standard classification accuracy assessment measures. When multiple indices were used along with six spectral bands (Blue, Green, Red, NIR, SWIR-1, SWIR-2), mangrove delineation potential measured by user's accuracy reached up to 97.47%. Further analysis shows that additional 14,807 hectares of small mangrove patches outside Sundarban Biosphere Reserve could also be identified using the proposed methodology. Therefore, this approach may improve mangrove delineation potential through remote sensing and further help conservation and restoration programs. [ABSTRACT FROM AUTHOR]

Rapid impact assessment of cyclones on coastal ecosystems is critical for timely rescue and rehabilitation operations in highly human‐dominated landscapes. Such assessments should also include damage assessments of vegetation for restoration planning in impacted natural landscapes. Our objective is to develop a remote sensing‐based approach combining satellite data derived from optical (Sentinel‐2), radar (Sentinel‐1), and LiDAR (Global Ecosystem Dynamics Investigation) platforms for rapid assessment of post‐cyclone inundation in non‐forested areas and vegetation damage in a primarily forested ecosystem. We apply this multi‐scalar approach for assessing damages caused by the cyclone Amphan that hit coastal India and Bangladesh in May 2020, severely flooding several districts in the two countries, and causing destruction to the Sundarban mangrove forests. Our analysis shows that at least 6821 sq. km. land across the 39 study districts was inundated even after 10 days after the cyclone. We further calculated the change in forest greenness as the difference in normalized difference vegetation index (NDVI) pre‐ and post‐cyclone. Our findings indicate a <0.2 unit decline in NDVI in 3.45 sq. km. of the forest. Rapid assessment of post‐cyclone damage in mangroves is challenging due to limited navigability of waterways, but critical for planning of mitigation and recovery measures. We demonstrate the utility of Otsu method, an automated statistical approach of the Google Earth Engine platform to identify inundated areas within days after a cyclone. Our radar‐based inundation analysis advances current practices because it requires minimal user inputs, and is effective in the presence of high cloud cover. Such rapid assessment, when complemented with detailed information on species and vegetation composition, can inform appropriate restoration efforts in severely impacted regions and help decision makers efficiently manage resources for recovery and aid relief. We provide the datasets from this study on an open platform to aid in future research and planning endeavors. [ABSTRACT FROM AUTHOR]

COVID-19 lockdown enforced distressed reverse migration in Sundarban, which caused an unprecedented population addition to the already devastated fragile Sundarban ecosystem. Acute poverty and food crisis prompted many migrants to explore forest-based living, thus enhancing fatal human–tiger conflicts. Families of deceased migrants face significant mental health trauma and catastrophic psychosocial consequences. [ABSTRACT FROM AUTHOR]

The coastal and low-lying areas of the Indian Sundarban are highly vulnerable to multiple hazards. Cyclonic hazards and floods have become a regular phenomenon in this fragile region. The villages and their households of this region are very much vulnerable to embankment breaching. Embankments in this region have been built since 1770, but it was so much unsuccessful in coping with storm surges or flood hazards. The study focuses on assessing the vulnerability of households that are spatially affected by embankment breaching. The methodology is composed of four dimensions of vulnerability including social, economic, physical, and environmental, which cover thirty-four indicators. From dimension-wise vulnerability, the overall vulnerability of households has been estimated. Based on the proximity to the embankment breaching location and impact, 330 households from eleven villages were selected to conduct the household survey. The study also adopted the relative effect score method to delineate the influence of indicators on the vulnerability of each specific village. The result shows that households belonging to Patibunia, Lakshmipur Abad, and Ganeshnagar occupy a very high categorical position in overall household vulnerability. The higher degree of exposure due to embankment breaching, unequal infrastructure, unstable economic structure, and a low level of education is considered to be highly sensitive towards vulnerability. The method is flexible and can be replicated and modified in other spatial scales for rapid decision-making. [Display omitted] • Vulnerability at the household level has been assessed using the Vulnerability Index of individual households. • Each household with its specific ID can distinguish the level of vulnerability. • A large number of households fall under the moderate to high vulnerable category. • Easily demarcate the vulnerable households and can access emergency response. [ABSTRACT FROM AUTHOR]

Mangrove forests in many parts of the world are declining at an alarming rate, which intensifies vulnerability in coastal ecosystems. An area like coastal West Bengal, including the Sundarban delta, where the world's largest mangrove populations have flourished, has a substantial negative impact of anthropogenic pressure since the early 15–16th century. Frequent coastal hazards, sea-level rise, and ever-increasing anthropogenic pressure have complicated the growth and regeneration of mangroves. In this study, an attempt has been made to map the patches of mangrove available in the coastal region of West Bengal along with their spatio-temporal, zonal pattern of change and probable reasons for those changes. The study approaches have been achieved by the analysis of Landsat data using several buffer zones from the coastline during 1989–2018 through geospatial techniques. The result indicates that despite a reduction of mangrove populations in the pre-and post-colonial era, overall mangrove areas have a marginally positive growth of about 0.47% (68.06 sq. km) of the total area during the assessment period. Although the mangrove area along the shoreline is decreasing faster, many new mangrove patches have appeared towards the mainland. Simultaneously, mangrove areas are encroached in the northern periphery of Sundarban Biosphere Reserve to convert them into settlements, agriculture, and aquaculture. This study could help to protect mangrove populations and implement appropriate conservation measures.

Contamination of potentially toxic metals (PTMs) can be detrimental to ecological processes, diversity and physiology of biological components of the surrounding habitat of estuarine and coastal environment. In our study, an inclusive approach to measure ecotoxicological parameters was followed considering spatial concentration of PTMs in the sediment system, sediment quality status, ecological risk level, bioconcentration in mangrove tissue and resulting biochemical and antioxidative response in mangroves Avicenniaalba and Excoecariaagallocha in eight locations in and around Indian Sundarban. Sediments in location L4 and L8 showed highest concentration of PTMs having maximum enrichment factors, geo-accumulation indices, contamination factors and pollution load indices signifying progressively deteriorated sediment quality of the estuary and considerable ecological risk for cadmium. Significant statistical correlation observed between chlorophyll content, free radical scavenging activity, reducing ability and stress enzyme activity (peroxidase, catalase and super oxide dismutase) of mangroves with PTM concentration in respective study areas. This work will help to frame effective prediction, assessment and management policies in this extremely eco-sensitive region by envisioning the status of augmented human activities leading to considerable metal stress in the estuarine sediment and consequent ecotoxicological response as the coping up mechanisms. [ABSTRACT FROM AUTHOR]

Climate changes and anthropogenic activities have paved the way for the dislocation of native species into areas located far away from their natural habitats. To this end, the Bay of Bengal and its adjacent coast have experienced the invasion of many alien species coming from different oceans, seas and bays around the world. Recently, a single specimen of the Twoblotch ponyfish (Nuchequula blochii) was captured. It had a total length of 69 mm and bodyweight 0.98 g. The specimen was caught at a depth of 18 m in the world's largest mangrove habitat, Sundarban, with a soft sandy bottom. Because the species N. blochii was previously recorded for the first time in the water area of Bangladesh, the single captured species above was considered as the 'second record.' There are several potential factors responsible for the introduction of this species in the Bay of the Bengal coast, one being the similar habitat conditions available to them. Because this species was previously reported from the water area of Bangladesh and is still appearing now, there is a possibility that it may become established in the water area of Bangladesh. [ABSTRACT FROM AUTHOR]

Scanning electron microscopy (SEM) is the most modern technique for plankton research. The present paper deals with the taxonomy and morphology of some rare and endangered planktonic chlorophytes in relation to scanning electron microscopy. Water samples from the distinct water body of the Sundarbans have been concentrated and examined by scanning electron microscopy. A total of 45 species, of which 17 species of Scenedesmaceae, 10 species each of Hydrodictyaceae and Desmidiaceae, five species of Chlorococcaceae, two species of Selenastraceae and only one species of Chlorellaceae were recorded from the study site. Some species were recorded as new and rare from the study area. About 18 species including nine extremely rare, seven occasional, six frequent, four sporadic and one abundant was recorded in the present study. A detailed taxonomic description with line drawings is also included in the present communication.

Sundarban mangrove is the largest continuous mangrove forest in the world and is the habitat of an incredible amount of biodiversity. Biodiversity loss and degradation of this highly ecologically productive mangrove forest due to climate change will have a tremendous impact on the livelihood of the people living in the deltaic region. The present study was aimed to find out the dynamics of change in different land cover for the greater Sundarban region. The multi-temporal Landsat images were used to understand the dynamics in three decades from 1998 to 2018. The analysis revealed that Sundarban mangrove forest changed very insignificantly. The change between 1998 and 2008 was approximately 1.2%, i.e. around 26.2 km2, and the change between the year 2008 and 2018 was approximately 1.27%, which consists of 28 km2. However, the dynamics of open mangrove forest and dense mangrove forest were found very high. The human habitat and aquaculture were found as the most rapidly expanding land-use type in this landscape. Area under human habitat has increased approximately 80%, i.e. nearly 654 km2 between 1998 and 2018; area under aquaculture has increased approximately 116% (i.e. around 231 km2) between 1998 and 2008. The MLP-Markov Chain based modelling of land-use has shown an overwhelming increase in human habitat in near future. However, being situated in the close vicinity of dense human population of the city Kolkata, the mangrove habitat remained intact, which is largely due to great amount of conservation efforts that have been exercised by the Govt. and the local forest department. The landscape statistical analysis for understanding the ecological dynamics of every land cover types showed that in 2018, the human habitat became second dominant category in this study area. The aquaculture practice for high economic value has pushed down the native agricultural practice in the region.

Agriculture is the main economic activity in Sundarban to sustain the basic livelihood of rural people. In recent decades, the nature of agriculture mainly cropping patterns, crop productivity, and agricultural land use is gradually changing because of various natural as well as anthropogenic factors. The frequent occurrence of climatic extremes over the Bay of Bengal has been directly or indirectly affected the agricultural system of the delta. In the wake of the 2009 cyclone Aila, the crop production in Gosaba rapidly declined due to high salinity and low pH in the soil. Most of the agricultural land remains a seasonal fallow due to the shortage of freshwater during the dry season. The direction of the surface slope has been altered by the unsystematic construction of embankment and haphazard construction of closure in river channels. The saucer-shaped appearance of the island causes massive drainage congestion induced waterlogging problem in the agricultural field. Waterlogging causes crop damage and low productivity. Farmers continue to face substantial monetary loss and entrapping in poverty. To overcome these issues, climate-resilient cropping strategy, proper maintenance of the drainage system, and adaptation of modern land reshaping techniques for diversified agriculture systems are urgently needed for the profound agro-based economic future of the delta.

An odonate survey was conducted throughout the southwestern region of Bangladesh, concentrating on eight districts and the Sundarban, from August 2014 to August 2016. A total of 50 species under 30 genera belonging to six families was recorded during the study period. Among these, 31 species belonged to Anisoptera and 19 to Zygoptera suborders. Libellulidae and Coenagrionidae were the most dominant anisopteran and zygopteran families with 28 and 17 species, respectively. One Zygoptera species Mortonagrion varalli was newly added to the odonate fauna of Bangladesh.