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
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
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
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
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
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.
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.
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.
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.
