The Sundarbans is the world’s most extensive natural mangrove forest and home to various natural resources. The population in the vicinity has increased, causing more dependency on the resources of the Sundarbans. Th...The Sundarbans is the world’s most extensive natural mangrove forest and home to various natural resources. The population in the vicinity has increased, causing more dependency on the resources of the Sundarbans. The increasing industrialization, urbanization, aquaculture, intensive agricultural practices, seaports, tourism facilities, and so on in the peripheral areas of the Sundarbans have made significant changes in the surrounding and upstream land uses of the Sundarbans. This situation may have detrimental influences on the ecosystem components of the Sundarbans. Therefore, it is highly demanded to prepare a piece of baseline information or database of different sources of pollution and their present status in the various components of the Sundarbans. This effort helps to identify issues and concerns, determine the key elements of the ecosystem to monitor the level or overall quality of the Sundarbans ecosystem. The present study systematically collects the potential sources of pollution, types, and current levels in the ecosystem components of the Sundarbans using academic databases, libraries, and online resources. Discharge of industrial waste into water, soil and air, heavy metal pollution, use of agrochemicals, oil (refined and crude) pollution, plastic materials from urban areas, and tourism are the major issues and concerns related to the sustainability of the Sundarbans ecosystem. The air quality of the Sundarbans is in good condition with 0 - 50 AQI of Bangladesh. While BOD, COD, TDS, TSS varied from 2.0 to 3.8 mg/L, 21.6 to 416 mg/L, 146.9 to 24,100 mg/L and 54 to 155 mg/L, respectively. Soil EC, organic carbon, total nitrogen, and total phosphorus ranged from 3.01 - 5.82 mS/cm, 1.41% - 2.69%, 0.51 - 1.05 mg/g, and 0.32 - 0.51 mg/g respectively. The air, water and soil quality parameters varied with the sites and seasons and not much at the state of contamination. Indeed, we must pay much attention to the Sundarbans’ air, water and soil quality with the massive and progressive change of the nearby land use pattern.展开更多
Rich genetic polymorphism is important for plants to adapt to changes because it enables the plant to make anatomical,physiological and biochemical changes in response to abiotic stress.Geomorphologic characteristics,...Rich genetic polymorphism is important for plants to adapt to changes because it enables the plant to make anatomical,physiological and biochemical changes in response to abiotic stress.Geomorphologic characteristics,demographic interference and a cumulative decrease in freshwater influx in the Indian Sundarbans region have proved detrimental to some economically important plants.In this study,genetic polymorphism of three mangrove species,Xylocarpus granatum,Excoecaria agallocha,and Phoenix paludosa,was assessed using RAPD and ISSR molecular markers.X.granatum,already in distress in the Sundarbans,had the least genetic polymorphism,14.56%in the RAPD analysis and 12.92% in the ISSR.Relatively higher genetic polymorphism was recorded for the profusely growing E.agallocha and P.paludosa: 24.66 and26.4% in RAPD; 24.87 and 20.32% in ISSR analysis respectively.A UPGMA dendrogram constructed using the similarity matrix from RAPD,ISSR and combined datashowed that for X.granatum,the least and highest salinity zones clustered together,whereas for E.agallocha and P.paludosa,higher and lower salinity areas clustered in different clades.Nei’s genetic diversity,calculated from RAPD and ISSR data,was also in accordance with 0.0637 and 0.0583 for X.granatum,respectively,much lower than0.0794 and 0.0818 for E.agallocha and 0.0799 and 0.0688 for P.paludosa.This opposing degree of polymorphism might be attributed to the profusely growing E.agallocha and P.paludosa and precarious status of X.granatum throughout the Indian Sundarbans.展开更多
Vertical occurrence of soil urease activity along with ammonia content from three distinct regions viz. Deep forest region (No tidal action and wave attack occurs as it is furthest from river shore and it contains max...Vertical occurrence of soil urease activity along with ammonia content from three distinct regions viz. Deep forest region (No tidal action and wave attack occurs as it is furthest from river shore and it contains maximum content of organic carbon and minimum soil salinity and silicate concentration. In this zone plenty of pneumatophores, below ground root and dense vegetation are found), Rooted region (It is situated in between Deep forest region and Un-rooted region. This region contains only pneumatophores but it is devoid of long roots and vegetations. It faces wave attack and tidal action less than that of Un-rooted region) and Un-rooted region (It is closest to river shore and faces maximum wave attack and tidal action;it contains minimum organic carbon but maximum soil salinity and silicate concentration. This zone is totally devoid of any roots, pneumatophores and vegetations) of Sundarban mangrove forest ecosystem, India revealed an interesting explanation. Soil urease activity showed a decreasing pattern with increase in depth from the deep forest region of the Sundarban forest ecosystem. Soil urease activity was found to be more sensitive to soil temperature and pH rather than soil salinity. This ensured that soil urease along with the microbes present in the Sundarban forest ecosystem are more tolerant to fluctuation in salinity than that of temperature. Soil ammonia concentration was found to be directly governed by the soil urease activity [The regression equation is Ammonia in soil = -1.64 + 0.0402 Urease Activity (R-Sq = 62.9%, P < 0.001, n = 41)].展开更多
Background: The article presents the first estimates of biomass and productivity for mangrove forests along the Oligohaline zone of the Sundarbans Reserve Forest (SRF), Bangladesh. This study was conducted overone ...Background: The article presents the first estimates of biomass and productivity for mangrove forests along the Oligohaline zone of the Sundarbans Reserve Forest (SRF), Bangladesh. This study was conducted overone year from March 2016 to April 20] 7. Stand structure, above and below-ground biomass changes, and litterfall production were measured within a 2100 m2 sample plot. Methods: All trees in the study plots were numbered and height (H) and diameter at breast height (DBH) were measured. Tree height (H) and DBH for each tree were measured in March 2016 and 2017. We apply the above and belowground biomass equation for estimating the biomass of the mangrove tree species (Chave et al. Oecologia 145:87-99, 2005; Komiyama et al. J Trop Ecol 21:471-477, 2005). Litterfall was collected using 1-mm mesh litter traps with collection area of 0.42 m2. Net Primary Production (NPP) was estimated by the summation method of Ogawa Primary productivity of Japanese forests: productivity of terrestrial communities, JIBP synthesis (1977) and Matsuura and Kajimoto Carbon dynamics of terrestrial ecosystem: Systems approach to global environment (2013). Results: Heritiero fomes has maintained its dominance of the stand and also suffered the highest tree mortality (2.4%) in the suppressed crown class. The total above-ground biomass (AGB) and below-ground biomass (BGB) of the studied stand was ]54.8 and 84.2 Mg.ha-1, respectively. Among the total biomass of the trees, 64.8% was allocated to AGB and 35.2% to BGB. In case of species-wise contribution of biomass allocation, Avicennia officinalis showed the highest score and Aglaia cucullota the lowest. Mean annual total litterfall was 10.1 Mg-ha 1.yr-1, with the maximum litterfall in winter or dry season and late summer or rainy season. The mean AGB increment and above-ground net primary productivity (AGNPP) were 7.1 and 17.2 Mg.ha-1.yr-1, respectively. Total net primary productivity (NPP) was estimated to be 21.0 Mg.ha Lyr-1 over the observed period. The results in the Sundarbans mangrove forests exhibited that mangrove communities with similar height and diameter produced different biomass production with the different basal area. The present analysis revealed that the root biomass was large enough and the mean ratio of above-/below-ground biomass was estimated to be 1.84. Conclusions: Mangrove communities growing at the oligohaline zone of the Sundarbans, Bangladesh showed high biomass and net primary production indicating their ecological and conservation significance that may be considered in future decision making process for the area as well as in understanding the role of Sundarbans mangrove forest on mitigating the effect of global warming.展开更多
In the Sundarban Mangrove forest microbial activities are dominantly involved in both the mineralization and decomposition processes that regulate nutrient profile in soil of different depth. It was found that besides...In the Sundarban Mangrove forest microbial activities are dominantly involved in both the mineralization and decomposition processes that regulate nutrient profile in soil of different depth. It was found that besides changing the water and soil quality, monsoonal cycle plays a crucial role in regulating microbial population distribution in the mangrove soil. Statistical analyses revealed that organic carbon was the most significant factor that regulated the total microbial population. The cellulose degrading bacteria, [mean value of CFU 14.32 × 106 (gm dry weight of soil)–1] was dominant throughout the year. The sulfate reducing bacteria showed an increasing trend along depth with a minimum value at the surface i.e. 6.113 × 106 (gm dry weight of soil)–1 and 12.312 × 106 (gm dry weight of soil)–1 at a depth of 60 cm. Intensification of monsoonal cycle could heavily affect microbe dominated soil biogeochemistry and subsequent change in the regional ecology of the Sundarban Mangrove Forest.展开更多
Tree biomass plays a key role in sustainable management by providing different aspects of ecosystem. Estimation of above ground biomass by non-destructive means requires the dex;elopment of allometric equations. Most ...Tree biomass plays a key role in sustainable management by providing different aspects of ecosystem. Estimation of above ground biomass by non-destructive means requires the dex;elopment of allometric equations. Most researchers used DBH (diameter at breast height) and TH (total height) to develop allometric equation for a tree. Very few spe- cies-specific allometric equations are currently available for shrubs to estimate of biomass from measured plant attributes. Therefore, we used some of readily measurable variables to develop allometric equations such as girth at collar-height (GcH) and height of girth measuring point (GMH) with total height (TH) for A. rotundifolia, a mangrove species of Sundarbans of Bangladesh, as it is too dwarf to take DBH and too ir- regular in base to take Girth at a fixed height. Linear, non-linear and logarithmic regression techniques were tried to determine the best re- gression model to estimate the above-ground biomass of stem, branch and leaf. A total of 186 regression equations were generated from the combination of independent variables. Best fit regression equations were determined by examining co-efficient of determination (R:), co-efficient of variation (Cv), mean-square of the error (Ms^r), residual mean error (Rmax), and F-value. Multiple linear regression models showed more efficient over other types of regression equation. The performance of regression equations was increased by inclusion of GMn as an independ- ent variable along with total height and GCH.展开更多
Populations of culturable microbes and activities of dehydrogenase & ?-D glucosidase were found maximum in surface soil and decreased with increase in depth in Sundarban mangrove environment.The maximum (13.529 X ...Populations of culturable microbes and activities of dehydrogenase & ?-D glucosidase were found maximum in surface soil and decreased with increase in depth in Sundarban mangrove environment.The maximum (13.529 X 106 C.F.U g-1 dry weight of soil) and minimum (11.547 X 106 C.F.U g-1 dry weight of soil) total microbial popu- lations in surface soil were recorded during po- st-monsoon and monsoon respectively. At 60 cm depth, the lower (6.396 X 106 C.F.U g-1 dry weight of soil) and higher (8.003 X 106 C.F.U g-1 dry weight of soil) numbers of total microbial populations were observed during monsoon and post-monsoon respectively. A decreasing trend of total microbial load, enzyme activities and nutrient status with organic carbon were found with increase in depth throughout the year. Present study revealed the relationship among depth integrated variations of physico-chemical compo- nents (viz. soil temperature, pH, moisture, orga- nic-C, .nitrogen, and available-P) and microbial populations as well as activity of dehydrogenase and ?-D glucosidase enzymes.展开更多
The ecosystem services provided by the Bangladesh Sundarbans contribute in various sectors especially to the livelihood of the surrounding peoples, but they are often overlooked in the valuation process. This study in...The ecosystem services provided by the Bangladesh Sundarbans contribute in various sectors especially to the livelihood of the surrounding peoples, but they are often overlooked in the valuation process. This study investigates the significance of ecosystem services on peoples' lives and how these services are affected by climate change and other factors. Here an economic valuation framework was used to list the ecosystem services provided by this mangrove forest. Direct uses included timber, gol- pata (Nypa fruticans), honey, beeswax, fish, shrimp larvae and tourism. Indirect uses included carbon storage, protection from cyclones and tidal surges, breeding and nursery grounds for the aquatic species, and biodiversity conservation. This work also found that the ecosystem services were diminished by fresh water flow reduction, overharvesting, sea level rise, salinity increase, poaching, and climate change. In the present context and future scenario, sea level rise will be an important contributor to changes in ecosystem services. But because many factors impact sea level rise, the impact of climate change takes on less importance than many other causes of ecosystem service degradation in the Bangladesh Sundarbans.展开更多
The Sundarbans, an UNESCO Heritage site has a large rural population which depends on natural resources for sustenance. The present paper deals with the management of the salt water intrusion of the Piyali River a tri...The Sundarbans, an UNESCO Heritage site has a large rural population which depends on natural resources for sustenance. The present paper deals with the management of the salt water intrusion of the Piyali River a tributary of the Matla River which empties into the Bay of Bengal. The study also delves into the population affected by the effects of the perennially saline river and their dependence on it for their livelihood. A look into the soil texture, seasonal variation in chloride content of soil along with pH and Electrical Conductivity (EC) levels of water sampled at different time and locations is analyzed in order to improve management options. With (EC) values of 17,000 mS and pH 8.94, sustaining the inhabitants in this area is quite challenging. Under the threat of climate change, increased levels of salinity arising from sea level rise and coastal flooding will pose a serious problem to the rural inhabitants of the Sundarbans. The predicted negative impacts of climate change are likely to bring new challenges in addition to magnifying existing problems, particularly in the Sundarbans community that already has limited capacity to adapt to these changes.展开更多
Sundarban Mangrove forest is highly productive marine ecosystem where halophilic microbes actively participate in bio-mineralization and biotransformation of minerals. The population of aerobic halophilic microbes was...Sundarban Mangrove forest is highly productive marine ecosystem where halophilic microbes actively participate in bio-mineralization and biotransformation of minerals. The population of aerobic halophilic microbes was studied to determine their distribution with the availability of different physicochemical parameters with increasing depth of this forest sediment. The present study revealed that microbes present in the top soil region were less tolerant to fluctuation in salinity than the middle and bottom segment. Microbes isolated from bottom segment showed higher growth rate in anaerobic condition. A decreasing trend of total microbial population and organic carbon content of soil were found with increase in depth. In contrary a reverse profile was found for salinity. A significant stratification was found to exist among microbial population and the salty nature of the soil of Sundarban Mangrove forest.展开更多
Aegiceras corniculatum grows as single-stemmed evergreen shrub or small tree in the Sundarbans mangrove forest of Bangladesh. The objectives of this study were to derive the allometric models for estimating above-grou...Aegiceras corniculatum grows as single-stemmed evergreen shrub or small tree in the Sundarbans mangrove forest of Bangladesh. The objectives of this study were to derive the allometric models for estimating above-ground biomass, nutrients (N, P and K) and carbon stock in A. corniclatum. A total of 8 linear models (y = aX + b, , y = aLogX + b, Logy = aX + b, Logy = aLogX + b, y = alnX + b, Lny = aX + b and Lny = alnX + b) with 64 regression equations were tested to derive the allometric model for biomass of each plant part;and nutrients and carbon stock in total aboveground biomass. The best fit allometric models were selected by considering the values of R<sup>2</sup>, CV, R<sub>mse</sub>, MS<sub>error</sub>, S<sub>a</sub>, S<sub>b</sub>, F value, AICc and Furnival Index. The selected allometric models were Logbiomass = 0.76LogDBH<sup>2</sup> - 1.39;Biomass = 0.07DBH<sup>2</sup> - 0.49;Logbiomass = 1.04LogDBH<sup>2</sup> - 1.80;Logbiomass = 1.04LogDBH<sup>2</sup> - 0.99;= 0.48DBH - 0.13 for leaves, branches, bark, stem without bark and total above-ground biomass respectively. The selected allometric models for Nitrogen, Phosphorous, Potassium and Carbon stock in total above-ground biomass were = 0.67DBH + 0.11;= 0.94DBH + 0.08;= 1.06DBH - 0.18;= 0.33DBH - 0.09 respectively.展开更多
Mangrove soils are well known for their high capacity of storing organic carbon (SOC) in various pools;however, a relatively small change in SOC pools could cause significant impacts on greenhouse gas concentrations. ...Mangrove soils are well known for their high capacity of storing organic carbon (SOC) in various pools;however, a relatively small change in SOC pools could cause significant impacts on greenhouse gas concentrations. Thus, for an in-depth understanding of SOC distribution and stock to predict the role of Sundarbans mangrove in mitigating global warming and greenhouse effects, different extraction methods were employed to fractionate the SOC of Sundarbans soils into cold-water (CWSC) and hot-water (HWSC) soluble, moderately labile (MLF), microbial biomass carbon (MBC), and resistant fractions (RF) using a newly developed modified-method. A significant variation in total SOC (p < 0.001), SOC stock (p < 0.001) and soil bulk density (p < 0.05) at the Sundarbans mangrove forest were observed. In most soils, bulk density increased from the surface to 100 cm depth. The total SOC concentrations were higher in most surface soils and ranged from 1.21% ± 0.02% to 8.19% ± 0.09%. However, C in lower layers may be more resistant than that of upper soils because of differences in compositions, sources and environmental conditions. SOC was predominately associated with the resistant fraction (81% - 97%), followed by MLF (2% - 10%), HWSC (1% - 4%), MBC (~0% - 4%), and CWSC (~0% - 3%). The significant positive correlations between different C fractions suggested that C pools are interdependent and need proper management plans to increase these pools in Sundarbans soils. The SOC stock of the studied areas ranged between 16.75 ± 3.83 to 135.12 ± 28.61 kg·C·m<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>2</sup> in 1 m soil profile and has an average of 31.80 kg·C·m<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>2</sup>. The substratum soils had more carbon than the upper layers in the Sundarbans wetland due to burial and preservation of carbon by frequent tidal inundation. A higher SOC stock in the soil profile and its primary association in resistant fractions suggested that Sundarbans mangrove soil is sequestering carbon and thereby serving as a significant carbon sink in Bangladesh.展开更多
Dependency on forest resources poses a threat to the environment in Patharghata, Bangladesh. Therefore, this study explores the role of forest resource in the life and livelihood of coastal people as well as to unders...Dependency on forest resources poses a threat to the environment in Patharghata, Bangladesh. Therefore, this study explores the role of forest resource in the life and livelihood of coastal people as well as to understand the effectiveness of forest and status of forest dependency in and around south-central coast in Patharghata, Bangladesh. We collected data randomly from 105 household heads through both open and close-ended questionnaire. To investigate the forest dependency and people’s perception regarding alternative solutions, Microsoft excel software program has been applied. The findings reveal that usage of fuelwood in cooking, housing structure, fish catching, honey & fodder collection significantly contributes to household dependency on forest resources, while other variables seem to be insignificant. Our study amplifies that the share of forest income to the total household income was only 19% while other earning sources provide</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">d</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> 81% income. The result shows that respondent people collect forest resources primarily for cooking purpose with a share of 71% where 9% forest resources are collected as fodder followed by 8% forest resource collection as food and sheltering purposes. Moreover, the study found that using alternative cooking system, artificial instruments, declaring the forest as tourist spot, changes in housing structure, occupation are some effective options to reduce forest dependency. The study concludes that these alternative options need more financial and other support from the government, non-government and other civil society organizations to cut down forest resource dependency.展开更多
Introduction:Seasonal and tidal variations in nutrient concentration and water quality were investigated in the western Sundarbans of Bangladesh during the post-monsoon,winter and monsoon seasons during 2010–2011.Met...Introduction:Seasonal and tidal variations in nutrient concentration and water quality were investigated in the western Sundarbans of Bangladesh during the post-monsoon,winter and monsoon seasons during 2010–2011.Methods:Water collected from the surface,middle and bottom layers at six locations of the Kholpetua-Arpangashia river system during high and low tides was analyzed for temperature,salinity,pH,dissolved oxygen(DO),total dissolved solids(TDS),electrical conductivity(EC)and dissolved nutrients(NO3–N,PO4–P,SO4 and NH3–N).Results:The study revealed that nutrient concentrations were influenced by seasonal changes.Mean nutrient levels during post-monsoon,winter and monsoon seasons,respectively,were in the following ranges:nitrate(0.06–0.40,0.06–0.46 and 0.08–0.46 mg/L);phosphate(0.09–0.18,0.05–0.42 and 0.10–0.16 mg/L);sulphate(58.71–86.14,68.68–119.01 and 78.15–136.47 mg/L)and ammonia(0.02–0.08,0.02–0.04 and 0.26–0.38 mg/L).Increased levels of PO4–P,SO4 and NH3–N and lower DO and salinity were recorded during the monsoon period.Most of the experimental sites showed higher NO3–N content during monsoon,whereas few elevated concentrations were observed during post-monsoon and winter periods.High and low tidal waters contained mean nutrient levels in the following ranges:nitrate(0.05–0.46 and 0.04–0.40 mg/L);phosphate(0.05–0.42 and 0.07–0.18 mg/L);sulphate(63.63–125.36 and 58.71–136.47 mg/L)and ammonia(0.02–0.38 and 0.02–0.37 mg/L)without following any distinct fluctuation patterns.The western part of the Sundarbans receives less freshwater input during the monsoon season than other areas of the ecosystem,which reduces the variability of nutrient levels and water quality components.Conclusions:This study provides considerable advances in understanding the seasonality of nutrient distribution with possible tidal influence.The data generated from this study will guide continuing efforts to support a sound management for coastal mangrove ecosystems.展开更多
Introduction:Mangrove forests are highly productive ecosystems distributed along the tropical coast line.Nutrient biogeochemistry of mangroves are primarly driven by both allochthonous and autochthonous sources.Charac...Introduction:Mangrove forests are highly productive ecosystems distributed along the tropical coast line.Nutrient biogeochemistry of mangroves are primarly driven by both allochthonous and autochthonous sources.Characterization of organic matter in coastal ecosystems enables to understand the biogeochemical transformation of organic matter and its influence on ecosystem productivity in response to various changing environmental conditions.Therefore,the elemental and stable carbon and nitrogen levels were employed to understand the organic matter(OM)dynamics in the Sundarban mangrove ecosystem(India-Bangladesh).Results:Differences in stable isotope values indicate that variable sources influence the OM dynamics in Sundarban sediments.The progressive enrichment inδ13C levels along the land-coastal continuum indicates that the terrestrial and marine inputs are dominant at the landward and seaward ends,respectively.The CuO oxidationderived lignin phenol monomers describe significant levels of total lignin are preserved in Sundarban mangrove sediments during diagenesis.The phenol monomer ratios are lower than the plant litter explaining that aromatic ring cleavage is the dominant mechanism for the lignin degradation.Furthermore,the Ad/Al ratios were higher than the plant litter explaining the oxidation of propyl side chain of vascular OM influencing the carbon cycling in Sundarban sediments.Largely,the Ad/Al ratios describe the vascular OM degradation is through the oxidation of propyl side chain.Conclusions:The regional variability in land-use regulates the spatial variability in C,N,OC/TN ratio,δ13C andδ15N between the Indian and the Bangladesh Sundarban mangroves and indicates that in the upstream terrestrial organic matter and/or mangrove plant litter contribute significant amount of organic matter,whereas the marine POC influences the organic matter dynamics in downstream.The three end-member mixing model applying terrestrial plant litter,seston,and marine POC as end-members explains the relative contribution of OM from various sources,and marine inputs were dominant in Sundarban sediments.展开更多
The Sundarban Mangrove Forest(SMF)is an intricate ecosystem containing the most varied and profuse natural resources of Bangladesh.This study presents empirical research,based on primary and secondary data,regarding t...The Sundarban Mangrove Forest(SMF)is an intricate ecosystem containing the most varied and profuse natural resources of Bangladesh.This study presents empirical research,based on primary and secondary data,regarding the social-ecological system(SES),social-ecological dynamics,different stakeholders and relevant management policies of small-scale or artisanal fisheries such as the SMF;showing how,despite extensive diversification,the livelihood activities of the artisanal fishers in the SMF all depend on the forest itself.Regardless of this critical importance of mangroves,however,deforestation continues due to immature death of mangroves,illegal logging,increased salinity,natural disasters and significant household consumption of mangrove wood by local people.As the mangroves are destroyed fish stocks,and other fishery resources are reduced,leading to moves of desperation among those whose livelihood has traditionally been fishing.The present study also considers several risks and shock factors in the fishers'livelihood:attacks by wild animals(especially tigers)and local bandits,illness,natural disasters,river bank erosion,and the cost of paying off corrupt officials.The artisanal fishers of the SMF have adopted different strategies for coping with these problems:developing partnerships,violating the fisheries management laws and regulations,migrating,placing greater responsibility on women,and bartering fishing knowledge and information.This study shows how the social component(human),the ecological component(mangrove resources)and the interphase aspects(local ecological knowledge,stakeholder's interest,and money lenders or middle man roles)of the SMF as an SES are linked in mutual interaction.It furthermore considers how the social-ecological dynamics of the SMF have negative impacts on artisanal fishermen's livelihoods.Hence there is an urgency to update existing policies and management issues for the sustainable utilization of the SMF resources,eventually contributing to the improvement of the artisanal fishers'livelihoods.展开更多
Species compositions in the mangrove habitats of China and India, especially on Hainan Island (China) and on the Sun- darbans and the Andaman & Nicobar Islands (India), are of interest, showing several similariti...Species compositions in the mangrove habitats of China and India, especially on Hainan Island (China) and on the Sun- darbans and the Andaman & Nicobar Islands (India), are of interest, showing several similarities and differences. The total mangrove areas of India cover about 6419 km^2 with 43 species (23 major and 20 minor species), while the mangrove areas of China cover about 150 km^2 with 26 speices (19 major and 7 minor speices). We carried out a comparison of mangrove floras in the Indian Sundarbans, Andaman & Nicobar Islands and in Hainan Island. The mangrove areas of the Indian Sundarbans comprise about 66.5% of the total Indian mangroves, presently covering an area of 4267 km^2 with 35 species from 22 genera and 16 families. There are 34 species from 17 genera and l 3 families in the Andaman & Nicobar Islands. Hainan Island is considered a distribution center of mangroves; it has the largest number of mangrove species in China, i.e., 25 species from 15 genera and 12 families, accounting for about 96% of the total number of mangrove species in China. The mangroves of Hainan Island and the Andaman & Nicobar Islands belong to island types, while those of Sundarbans belong to inter-tidal deltaic types. Differences in soil type, rainfall, temperature, tidal fluctuation and other climatic features possibly cause variations in floristic composition of these regions.展开更多
孙德尔本斯湿地(Sundarbans Wetland of International Importance)是世界面积最大的红树林连续分布区,1992年被列为世界自然保护联盟(IUCN)国际重要湿地名录,编号为560。孙德尔本斯湿地位于孟加拉共和国西南海滨,濒临孟加拉湾,地处恒...孙德尔本斯湿地(Sundarbans Wetland of International Importance)是世界面积最大的红树林连续分布区,1992年被列为世界自然保护联盟(IUCN)国际重要湿地名录,编号为560。孙德尔本斯湿地位于孟加拉共和国西南海滨,濒临孟加拉湾,地处恒河、布拉马普特拉河与梅克纳河三河交汇处,也是恒河三角洲的组成部分。展开更多
文摘The Sundarbans is the world’s most extensive natural mangrove forest and home to various natural resources. The population in the vicinity has increased, causing more dependency on the resources of the Sundarbans. The increasing industrialization, urbanization, aquaculture, intensive agricultural practices, seaports, tourism facilities, and so on in the peripheral areas of the Sundarbans have made significant changes in the surrounding and upstream land uses of the Sundarbans. This situation may have detrimental influences on the ecosystem components of the Sundarbans. Therefore, it is highly demanded to prepare a piece of baseline information or database of different sources of pollution and their present status in the various components of the Sundarbans. This effort helps to identify issues and concerns, determine the key elements of the ecosystem to monitor the level or overall quality of the Sundarbans ecosystem. The present study systematically collects the potential sources of pollution, types, and current levels in the ecosystem components of the Sundarbans using academic databases, libraries, and online resources. Discharge of industrial waste into water, soil and air, heavy metal pollution, use of agrochemicals, oil (refined and crude) pollution, plastic materials from urban areas, and tourism are the major issues and concerns related to the sustainability of the Sundarbans ecosystem. The air quality of the Sundarbans is in good condition with 0 - 50 AQI of Bangladesh. While BOD, COD, TDS, TSS varied from 2.0 to 3.8 mg/L, 21.6 to 416 mg/L, 146.9 to 24,100 mg/L and 54 to 155 mg/L, respectively. Soil EC, organic carbon, total nitrogen, and total phosphorus ranged from 3.01 - 5.82 mS/cm, 1.41% - 2.69%, 0.51 - 1.05 mg/g, and 0.32 - 0.51 mg/g respectively. The air, water and soil quality parameters varied with the sites and seasons and not much at the state of contamination. Indeed, we must pay much attention to the Sundarbans’ air, water and soil quality with the massive and progressive change of the nearby land use pattern.
基金funded by the Indian Statistical Institute,Kolkata
文摘Rich genetic polymorphism is important for plants to adapt to changes because it enables the plant to make anatomical,physiological and biochemical changes in response to abiotic stress.Geomorphologic characteristics,demographic interference and a cumulative decrease in freshwater influx in the Indian Sundarbans region have proved detrimental to some economically important plants.In this study,genetic polymorphism of three mangrove species,Xylocarpus granatum,Excoecaria agallocha,and Phoenix paludosa,was assessed using RAPD and ISSR molecular markers.X.granatum,already in distress in the Sundarbans,had the least genetic polymorphism,14.56%in the RAPD analysis and 12.92% in the ISSR.Relatively higher genetic polymorphism was recorded for the profusely growing E.agallocha and P.paludosa: 24.66 and26.4% in RAPD; 24.87 and 20.32% in ISSR analysis respectively.A UPGMA dendrogram constructed using the similarity matrix from RAPD,ISSR and combined datashowed that for X.granatum,the least and highest salinity zones clustered together,whereas for E.agallocha and P.paludosa,higher and lower salinity areas clustered in different clades.Nei’s genetic diversity,calculated from RAPD and ISSR data,was also in accordance with 0.0637 and 0.0583 for X.granatum,respectively,much lower than0.0794 and 0.0818 for E.agallocha and 0.0799 and 0.0688 for P.paludosa.This opposing degree of polymorphism might be attributed to the profusely growing E.agallocha and P.paludosa and precarious status of X.granatum throughout the Indian Sundarbans.
文摘Vertical occurrence of soil urease activity along with ammonia content from three distinct regions viz. Deep forest region (No tidal action and wave attack occurs as it is furthest from river shore and it contains maximum content of organic carbon and minimum soil salinity and silicate concentration. In this zone plenty of pneumatophores, below ground root and dense vegetation are found), Rooted region (It is situated in between Deep forest region and Un-rooted region. This region contains only pneumatophores but it is devoid of long roots and vegetations. It faces wave attack and tidal action less than that of Un-rooted region) and Un-rooted region (It is closest to river shore and faces maximum wave attack and tidal action;it contains minimum organic carbon but maximum soil salinity and silicate concentration. This zone is totally devoid of any roots, pneumatophores and vegetations) of Sundarban mangrove forest ecosystem, India revealed an interesting explanation. Soil urease activity showed a decreasing pattern with increase in depth from the deep forest region of the Sundarban forest ecosystem. Soil urease activity was found to be more sensitive to soil temperature and pH rather than soil salinity. This ensured that soil urease along with the microbes present in the Sundarban forest ecosystem are more tolerant to fluctuation in salinity than that of temperature. Soil ammonia concentration was found to be directly governed by the soil urease activity [The regression equation is Ammonia in soil = -1.64 + 0.0402 Urease Activity (R-Sq = 62.9%, P < 0.001, n = 41)].
基金supported by a Grant-in-Aid for Scientific Research (JSPS KAKENHI 15F15389) from the Japan Society for the promotion of Science to Professor Akira Osawa and Md.Kamruzzaman
文摘Background: The article presents the first estimates of biomass and productivity for mangrove forests along the Oligohaline zone of the Sundarbans Reserve Forest (SRF), Bangladesh. This study was conducted overone year from March 2016 to April 20] 7. Stand structure, above and below-ground biomass changes, and litterfall production were measured within a 2100 m2 sample plot. Methods: All trees in the study plots were numbered and height (H) and diameter at breast height (DBH) were measured. Tree height (H) and DBH for each tree were measured in March 2016 and 2017. We apply the above and belowground biomass equation for estimating the biomass of the mangrove tree species (Chave et al. Oecologia 145:87-99, 2005; Komiyama et al. J Trop Ecol 21:471-477, 2005). Litterfall was collected using 1-mm mesh litter traps with collection area of 0.42 m2. Net Primary Production (NPP) was estimated by the summation method of Ogawa Primary productivity of Japanese forests: productivity of terrestrial communities, JIBP synthesis (1977) and Matsuura and Kajimoto Carbon dynamics of terrestrial ecosystem: Systems approach to global environment (2013). Results: Heritiero fomes has maintained its dominance of the stand and also suffered the highest tree mortality (2.4%) in the suppressed crown class. The total above-ground biomass (AGB) and below-ground biomass (BGB) of the studied stand was ]54.8 and 84.2 Mg.ha-1, respectively. Among the total biomass of the trees, 64.8% was allocated to AGB and 35.2% to BGB. In case of species-wise contribution of biomass allocation, Avicennia officinalis showed the highest score and Aglaia cucullota the lowest. Mean annual total litterfall was 10.1 Mg-ha 1.yr-1, with the maximum litterfall in winter or dry season and late summer or rainy season. The mean AGB increment and above-ground net primary productivity (AGNPP) were 7.1 and 17.2 Mg.ha-1.yr-1, respectively. Total net primary productivity (NPP) was estimated to be 21.0 Mg.ha Lyr-1 over the observed period. The results in the Sundarbans mangrove forests exhibited that mangrove communities with similar height and diameter produced different biomass production with the different basal area. The present analysis revealed that the root biomass was large enough and the mean ratio of above-/below-ground biomass was estimated to be 1.84. Conclusions: Mangrove communities growing at the oligohaline zone of the Sundarbans, Bangladesh showed high biomass and net primary production indicating their ecological and conservation significance that may be considered in future decision making process for the area as well as in understanding the role of Sundarbans mangrove forest on mitigating the effect of global warming.
文摘In the Sundarban Mangrove forest microbial activities are dominantly involved in both the mineralization and decomposition processes that regulate nutrient profile in soil of different depth. It was found that besides changing the water and soil quality, monsoonal cycle plays a crucial role in regulating microbial population distribution in the mangrove soil. Statistical analyses revealed that organic carbon was the most significant factor that regulated the total microbial population. The cellulose degrading bacteria, [mean value of CFU 14.32 × 106 (gm dry weight of soil)–1] was dominant throughout the year. The sulfate reducing bacteria showed an increasing trend along depth with a minimum value at the surface i.e. 6.113 × 106 (gm dry weight of soil)–1 and 12.312 × 106 (gm dry weight of soil)–1 at a depth of 60 cm. Intensification of monsoonal cycle could heavily affect microbe dominated soil biogeochemistry and subsequent change in the regional ecology of the Sundarban Mangrove Forest.
文摘Tree biomass plays a key role in sustainable management by providing different aspects of ecosystem. Estimation of above ground biomass by non-destructive means requires the dex;elopment of allometric equations. Most researchers used DBH (diameter at breast height) and TH (total height) to develop allometric equation for a tree. Very few spe- cies-specific allometric equations are currently available for shrubs to estimate of biomass from measured plant attributes. Therefore, we used some of readily measurable variables to develop allometric equations such as girth at collar-height (GcH) and height of girth measuring point (GMH) with total height (TH) for A. rotundifolia, a mangrove species of Sundarbans of Bangladesh, as it is too dwarf to take DBH and too ir- regular in base to take Girth at a fixed height. Linear, non-linear and logarithmic regression techniques were tried to determine the best re- gression model to estimate the above-ground biomass of stem, branch and leaf. A total of 186 regression equations were generated from the combination of independent variables. Best fit regression equations were determined by examining co-efficient of determination (R:), co-efficient of variation (Cv), mean-square of the error (Ms^r), residual mean error (Rmax), and F-value. Multiple linear regression models showed more efficient over other types of regression equation. The performance of regression equations was increased by inclusion of GMn as an independ- ent variable along with total height and GCH.
文摘Populations of culturable microbes and activities of dehydrogenase & ?-D glucosidase were found maximum in surface soil and decreased with increase in depth in Sundarban mangrove environment.The maximum (13.529 X 106 C.F.U g-1 dry weight of soil) and minimum (11.547 X 106 C.F.U g-1 dry weight of soil) total microbial popu- lations in surface soil were recorded during po- st-monsoon and monsoon respectively. At 60 cm depth, the lower (6.396 X 106 C.F.U g-1 dry weight of soil) and higher (8.003 X 106 C.F.U g-1 dry weight of soil) numbers of total microbial populations were observed during monsoon and post-monsoon respectively. A decreasing trend of total microbial load, enzyme activities and nutrient status with organic carbon were found with increase in depth throughout the year. Present study revealed the relationship among depth integrated variations of physico-chemical compo- nents (viz. soil temperature, pH, moisture, orga- nic-C, .nitrogen, and available-P) and microbial populations as well as activity of dehydrogenase and ?-D glucosidase enzymes.
基金the support of TWASUSM fellowship for funding the PhD study of the corresponding author
文摘The ecosystem services provided by the Bangladesh Sundarbans contribute in various sectors especially to the livelihood of the surrounding peoples, but they are often overlooked in the valuation process. This study investigates the significance of ecosystem services on peoples' lives and how these services are affected by climate change and other factors. Here an economic valuation framework was used to list the ecosystem services provided by this mangrove forest. Direct uses included timber, gol- pata (Nypa fruticans), honey, beeswax, fish, shrimp larvae and tourism. Indirect uses included carbon storage, protection from cyclones and tidal surges, breeding and nursery grounds for the aquatic species, and biodiversity conservation. This work also found that the ecosystem services were diminished by fresh water flow reduction, overharvesting, sea level rise, salinity increase, poaching, and climate change. In the present context and future scenario, sea level rise will be an important contributor to changes in ecosystem services. But because many factors impact sea level rise, the impact of climate change takes on less importance than many other causes of ecosystem service degradation in the Bangladesh Sundarbans.
文摘The Sundarbans, an UNESCO Heritage site has a large rural population which depends on natural resources for sustenance. The present paper deals with the management of the salt water intrusion of the Piyali River a tributary of the Matla River which empties into the Bay of Bengal. The study also delves into the population affected by the effects of the perennially saline river and their dependence on it for their livelihood. A look into the soil texture, seasonal variation in chloride content of soil along with pH and Electrical Conductivity (EC) levels of water sampled at different time and locations is analyzed in order to improve management options. With (EC) values of 17,000 mS and pH 8.94, sustaining the inhabitants in this area is quite challenging. Under the threat of climate change, increased levels of salinity arising from sea level rise and coastal flooding will pose a serious problem to the rural inhabitants of the Sundarbans. The predicted negative impacts of climate change are likely to bring new challenges in addition to magnifying existing problems, particularly in the Sundarbans community that already has limited capacity to adapt to these changes.
文摘Sundarban Mangrove forest is highly productive marine ecosystem where halophilic microbes actively participate in bio-mineralization and biotransformation of minerals. The population of aerobic halophilic microbes was studied to determine their distribution with the availability of different physicochemical parameters with increasing depth of this forest sediment. The present study revealed that microbes present in the top soil region were less tolerant to fluctuation in salinity than the middle and bottom segment. Microbes isolated from bottom segment showed higher growth rate in anaerobic condition. A decreasing trend of total microbial population and organic carbon content of soil were found with increase in depth. In contrary a reverse profile was found for salinity. A significant stratification was found to exist among microbial population and the salty nature of the soil of Sundarban Mangrove forest.
文摘Aegiceras corniculatum grows as single-stemmed evergreen shrub or small tree in the Sundarbans mangrove forest of Bangladesh. The objectives of this study were to derive the allometric models for estimating above-ground biomass, nutrients (N, P and K) and carbon stock in A. corniclatum. A total of 8 linear models (y = aX + b, , y = aLogX + b, Logy = aX + b, Logy = aLogX + b, y = alnX + b, Lny = aX + b and Lny = alnX + b) with 64 regression equations were tested to derive the allometric model for biomass of each plant part;and nutrients and carbon stock in total aboveground biomass. The best fit allometric models were selected by considering the values of R<sup>2</sup>, CV, R<sub>mse</sub>, MS<sub>error</sub>, S<sub>a</sub>, S<sub>b</sub>, F value, AICc and Furnival Index. The selected allometric models were Logbiomass = 0.76LogDBH<sup>2</sup> - 1.39;Biomass = 0.07DBH<sup>2</sup> - 0.49;Logbiomass = 1.04LogDBH<sup>2</sup> - 1.80;Logbiomass = 1.04LogDBH<sup>2</sup> - 0.99;= 0.48DBH - 0.13 for leaves, branches, bark, stem without bark and total above-ground biomass respectively. The selected allometric models for Nitrogen, Phosphorous, Potassium and Carbon stock in total above-ground biomass were = 0.67DBH + 0.11;= 0.94DBH + 0.08;= 1.06DBH - 0.18;= 0.33DBH - 0.09 respectively.
文摘Mangrove soils are well known for their high capacity of storing organic carbon (SOC) in various pools;however, a relatively small change in SOC pools could cause significant impacts on greenhouse gas concentrations. Thus, for an in-depth understanding of SOC distribution and stock to predict the role of Sundarbans mangrove in mitigating global warming and greenhouse effects, different extraction methods were employed to fractionate the SOC of Sundarbans soils into cold-water (CWSC) and hot-water (HWSC) soluble, moderately labile (MLF), microbial biomass carbon (MBC), and resistant fractions (RF) using a newly developed modified-method. A significant variation in total SOC (p < 0.001), SOC stock (p < 0.001) and soil bulk density (p < 0.05) at the Sundarbans mangrove forest were observed. In most soils, bulk density increased from the surface to 100 cm depth. The total SOC concentrations were higher in most surface soils and ranged from 1.21% ± 0.02% to 8.19% ± 0.09%. However, C in lower layers may be more resistant than that of upper soils because of differences in compositions, sources and environmental conditions. SOC was predominately associated with the resistant fraction (81% - 97%), followed by MLF (2% - 10%), HWSC (1% - 4%), MBC (~0% - 4%), and CWSC (~0% - 3%). The significant positive correlations between different C fractions suggested that C pools are interdependent and need proper management plans to increase these pools in Sundarbans soils. The SOC stock of the studied areas ranged between 16.75 ± 3.83 to 135.12 ± 28.61 kg·C·m<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>2</sup> in 1 m soil profile and has an average of 31.80 kg·C·m<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>2</sup>. The substratum soils had more carbon than the upper layers in the Sundarbans wetland due to burial and preservation of carbon by frequent tidal inundation. A higher SOC stock in the soil profile and its primary association in resistant fractions suggested that Sundarbans mangrove soil is sequestering carbon and thereby serving as a significant carbon sink in Bangladesh.
文摘Dependency on forest resources poses a threat to the environment in Patharghata, Bangladesh. Therefore, this study explores the role of forest resource in the life and livelihood of coastal people as well as to understand the effectiveness of forest and status of forest dependency in and around south-central coast in Patharghata, Bangladesh. We collected data randomly from 105 household heads through both open and close-ended questionnaire. To investigate the forest dependency and people’s perception regarding alternative solutions, Microsoft excel software program has been applied. The findings reveal that usage of fuelwood in cooking, housing structure, fish catching, honey & fodder collection significantly contributes to household dependency on forest resources, while other variables seem to be insignificant. Our study amplifies that the share of forest income to the total household income was only 19% while other earning sources provide</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">d</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> 81% income. The result shows that respondent people collect forest resources primarily for cooking purpose with a share of 71% where 9% forest resources are collected as fodder followed by 8% forest resource collection as food and sheltering purposes. Moreover, the study found that using alternative cooking system, artificial instruments, declaring the forest as tourist spot, changes in housing structure, occupation are some effective options to reduce forest dependency. The study concludes that these alternative options need more financial and other support from the government, non-government and other civil society organizations to cut down forest resource dependency.
基金Ministry of Education,Government of the Peoples’Republic of Bangladesh provided the necessary financial support under the Grants for Advanced Research in Science to carry out the present study.The authors would like to acknowledge the support of the laboratory staff of the Fisheries and Marine Resource Technology Discipline and Environmental Science Discipline of Khulna University during sample analysis in the laboratory.Thanks are due to the graduate and undergraduate students for their generous cooperation during field observation,in-situ measurement and laboratory analysis.Support of the authorities of the Forest Department of Bangladesh are appreciated.The authors would like to thank two anonymous reviewers for their valuable comments and suggestions that helped improve the manuscript.
文摘Introduction:Seasonal and tidal variations in nutrient concentration and water quality were investigated in the western Sundarbans of Bangladesh during the post-monsoon,winter and monsoon seasons during 2010–2011.Methods:Water collected from the surface,middle and bottom layers at six locations of the Kholpetua-Arpangashia river system during high and low tides was analyzed for temperature,salinity,pH,dissolved oxygen(DO),total dissolved solids(TDS),electrical conductivity(EC)and dissolved nutrients(NO3–N,PO4–P,SO4 and NH3–N).Results:The study revealed that nutrient concentrations were influenced by seasonal changes.Mean nutrient levels during post-monsoon,winter and monsoon seasons,respectively,were in the following ranges:nitrate(0.06–0.40,0.06–0.46 and 0.08–0.46 mg/L);phosphate(0.09–0.18,0.05–0.42 and 0.10–0.16 mg/L);sulphate(58.71–86.14,68.68–119.01 and 78.15–136.47 mg/L)and ammonia(0.02–0.08,0.02–0.04 and 0.26–0.38 mg/L).Increased levels of PO4–P,SO4 and NH3–N and lower DO and salinity were recorded during the monsoon period.Most of the experimental sites showed higher NO3–N content during monsoon,whereas few elevated concentrations were observed during post-monsoon and winter periods.High and low tidal waters contained mean nutrient levels in the following ranges:nitrate(0.05–0.46 and 0.04–0.40 mg/L);phosphate(0.05–0.42 and 0.07–0.18 mg/L);sulphate(63.63–125.36 and 58.71–136.47 mg/L)and ammonia(0.02–0.38 and 0.02–0.37 mg/L)without following any distinct fluctuation patterns.The western part of the Sundarbans receives less freshwater input during the monsoon season than other areas of the ecosystem,which reduces the variability of nutrient levels and water quality components.Conclusions:This study provides considerable advances in understanding the seasonality of nutrient distribution with possible tidal influence.The data generated from this study will guide continuing efforts to support a sound management for coastal mangrove ecosystems.
文摘Introduction:Mangrove forests are highly productive ecosystems distributed along the tropical coast line.Nutrient biogeochemistry of mangroves are primarly driven by both allochthonous and autochthonous sources.Characterization of organic matter in coastal ecosystems enables to understand the biogeochemical transformation of organic matter and its influence on ecosystem productivity in response to various changing environmental conditions.Therefore,the elemental and stable carbon and nitrogen levels were employed to understand the organic matter(OM)dynamics in the Sundarban mangrove ecosystem(India-Bangladesh).Results:Differences in stable isotope values indicate that variable sources influence the OM dynamics in Sundarban sediments.The progressive enrichment inδ13C levels along the land-coastal continuum indicates that the terrestrial and marine inputs are dominant at the landward and seaward ends,respectively.The CuO oxidationderived lignin phenol monomers describe significant levels of total lignin are preserved in Sundarban mangrove sediments during diagenesis.The phenol monomer ratios are lower than the plant litter explaining that aromatic ring cleavage is the dominant mechanism for the lignin degradation.Furthermore,the Ad/Al ratios were higher than the plant litter explaining the oxidation of propyl side chain of vascular OM influencing the carbon cycling in Sundarban sediments.Largely,the Ad/Al ratios describe the vascular OM degradation is through the oxidation of propyl side chain.Conclusions:The regional variability in land-use regulates the spatial variability in C,N,OC/TN ratio,δ13C andδ15N between the Indian and the Bangladesh Sundarban mangroves and indicates that in the upstream terrestrial organic matter and/or mangrove plant litter contribute significant amount of organic matter,whereas the marine POC influences the organic matter dynamics in downstream.The three end-member mixing model applying terrestrial plant litter,seston,and marine POC as end-members explains the relative contribution of OM from various sources,and marine inputs were dominant in Sundarban sediments.
基金We thank the fishers and other stakeholders who generously shared their time and knowledge.We are grateful to DAAD(Deutscher Akademisher Austausdienst),for financial support to conduct the research.We thank the anonymous reviewers and the editorial board for their helpful comments and suggestions on earlier versions of the manuscript.Special thanks to David Huisjen for helping with the English edition.
文摘The Sundarban Mangrove Forest(SMF)is an intricate ecosystem containing the most varied and profuse natural resources of Bangladesh.This study presents empirical research,based on primary and secondary data,regarding the social-ecological system(SES),social-ecological dynamics,different stakeholders and relevant management policies of small-scale or artisanal fisheries such as the SMF;showing how,despite extensive diversification,the livelihood activities of the artisanal fishers in the SMF all depend on the forest itself.Regardless of this critical importance of mangroves,however,deforestation continues due to immature death of mangroves,illegal logging,increased salinity,natural disasters and significant household consumption of mangrove wood by local people.As the mangroves are destroyed fish stocks,and other fishery resources are reduced,leading to moves of desperation among those whose livelihood has traditionally been fishing.The present study also considers several risks and shock factors in the fishers'livelihood:attacks by wild animals(especially tigers)and local bandits,illness,natural disasters,river bank erosion,and the cost of paying off corrupt officials.The artisanal fishers of the SMF have adopted different strategies for coping with these problems:developing partnerships,violating the fisheries management laws and regulations,migrating,placing greater responsibility on women,and bartering fishing knowledge and information.This study shows how the social component(human),the ecological component(mangrove resources)and the interphase aspects(local ecological knowledge,stakeholder's interest,and money lenders or middle man roles)of the SMF as an SES are linked in mutual interaction.It furthermore considers how the social-ecological dynamics of the SMF have negative impacts on artisanal fishermen's livelihoods.Hence there is an urgency to update existing policies and management issues for the sustainable utilization of the SMF resources,eventually contributing to the improvement of the artisanal fishers'livelihoods.
基金supported by the National Natural Science Foundation of China (Grant No. 40701191)
文摘Species compositions in the mangrove habitats of China and India, especially on Hainan Island (China) and on the Sun- darbans and the Andaman & Nicobar Islands (India), are of interest, showing several similarities and differences. The total mangrove areas of India cover about 6419 km^2 with 43 species (23 major and 20 minor species), while the mangrove areas of China cover about 150 km^2 with 26 speices (19 major and 7 minor speices). We carried out a comparison of mangrove floras in the Indian Sundarbans, Andaman & Nicobar Islands and in Hainan Island. The mangrove areas of the Indian Sundarbans comprise about 66.5% of the total Indian mangroves, presently covering an area of 4267 km^2 with 35 species from 22 genera and 16 families. There are 34 species from 17 genera and l 3 families in the Andaman & Nicobar Islands. Hainan Island is considered a distribution center of mangroves; it has the largest number of mangrove species in China, i.e., 25 species from 15 genera and 12 families, accounting for about 96% of the total number of mangrove species in China. The mangroves of Hainan Island and the Andaman & Nicobar Islands belong to island types, while those of Sundarbans belong to inter-tidal deltaic types. Differences in soil type, rainfall, temperature, tidal fluctuation and other climatic features possibly cause variations in floristic composition of these regions.
文摘孙德尔本斯湿地(Sundarbans Wetland of International Importance)是世界面积最大的红树林连续分布区,1992年被列为世界自然保护联盟(IUCN)国际重要湿地名录,编号为560。孙德尔本斯湿地位于孟加拉共和国西南海滨,濒临孟加拉湾,地处恒河、布拉马普特拉河与梅克纳河三河交汇处,也是恒河三角洲的组成部分。