Showing papers on "Heritiera fomes published in 2017"

Climate change-induced salinity variation impacts on a stenoecious mangrove species in the Indian Sundarbans.

Abstract: The alterations in the salinity profile are an indirect, but potentially sensitive, indicator for detecting changes in precipitation, evaporation, river run-off, glacier retreat, and ice melt. These changes have a high impact on the growth of coastal plant species, such as mangroves. Here, we present estimates of the variability of salinity and the biomass of a stenoecious mangrove species (Heritiera fomes, commonly referred to as Sundari) in the aquatic subsystem of the lower Gangetic delta based on a dataset from 2004 to 2015. We highlight the impact of salinity alteration on the change in aboveground biomass of this endangered species that, due to different salinity profile in the western and central sectors of the lower Gangetic plain, shows an increase only in the former sector, where the salinity is dropping and low growth in the latter, where the salinity is increasing.

The impact of climate change and aquatic salinization on mangrove species in the Bangladesh Sundarbans.

Abstract: This paper investigates the possible impacts of climate change on aquatic salinity and mangrove species in the Bangladesh Sundarbans. The impact analysis combines the salinity tolerance ranges of predominant mangrove species with aquatic salinity measures in 27 scenarios of climate change by 2050. The estimates indicate significant overall losses for Heritiera fomes; substantial gains for Excoecaria agallocha; modest changes for Avicennia alba, A. marina, A. officinalis, Ceriops decandra, and Sonneratia apetala; and mixed results for species combinations. Changes in mangrove stocks are likely to change the prospects for forest-based livelihoods. The implications for neighboring communities are assessed by computing changes in high-value mangrove species for the five sub-districts in the Sundarbans. The results of the impact analysis indicate highly varied patterns of gain and loss across the five sub-districts. Overall, however, the results suggest that salinity-induced mangrove migration will have a strongly regressive impact on the value of timber stocks because of the loss of highest value timber species, Heritiera fomes. In addition, the augmented potential for honey production will likely increase conflicts between humans and wildlife in the region.

Climate Variability and Mangrove Cover Dynamics at Species Level in the Sundarbans, Bangladesh

Abstract: Mangrove ecosystems are complex in nature. For monitoring the impact of climate variability in this ecosystem, a multidisciplinary approach is a prerequisite. Changes in temperature and rainfall pattern have been suggested as an influential factor responsible for the change in mangrove species composition and spatial distribution. The main aim of this study was to assess the relationship between temperature, rainfall pattern and dynamics of mangrove species in the Sundarbans, Bangladesh, over a 38 year time period from 1977 to 2015. To assess the relationship, a three stage analytical process was employed. Primarily, the trend of temperature and rainfall over the study period were identified using a linear trend model; then, the supervised maximum likelihood classifier technique was employed to classify images recorded by Landsat series and post-classification comparison techniques were used to detect changes at species level. The rate of change of different mangrove species was also estimated in the second stage. Finally, the relationship between temperature, rainfall and the dynamics of mangroves at species level was determined using a simple linear regression model. The results show a significant statistical relationship between temperature, rainfall and the dynamics of mangrove species. The trends of change for Heritiera fomes and Sonneratia apelatala show a strong relationship with temperature and rainfall, while Ceriops decandra shows a weak relationship. In contrast, Excoecaria agallocha and Xylocarpus mekongensis do not show any significant relationship with temperature and rainfall. On the basis of our results, it can be concluded that temperature and rainfall are important climatic factors influencing the dynamics of three major mangrove species viz. H. fomes, S. apelatala and C. decandra in the Sundarbans.

Mangroves in India and Climate Change: An Overview

Abstract: In India, mangroves occupy an area of 4740 km2, accounting for about 3 % of the world’s mangrove cover. Sundarbans in India and Bangladesh is the largest single block of mangrove forest in the world, and is the only mangrove forest in the world, colonized with Royal Bengal tigers and other globally threatened animal species. Indian mangroves in Bhitarkanika of Odisha are the one among the two mangrove genetic paradises of the world. India’s mangroves can be broadly categorized into deltaic, backwater-estuarine, and insular types. About 58 % of the mangroves occur on the east coast along the Bay of Bengal, 29 % on the west coast bordering the Arabian Sea, and 13 % on Andaman and Nicobar Islands. Most spectacular mangroves are found in Sundarbans in West Bengal (44 %), followed by Gujarat (23 %) and Andaman and Nicobar Islands (13 %). The mangrove forests are very dense in 1472 km2 (31 %), moderate in 1391 km2 (29 %), and sparse in 1877 km2 (40 %). Mangrove forest ecosystems in India support diverse groups of organisms comprising about 4000 floral and faunal species, and mangrove forests harbor 39 mangrove plant species that is 56 % of world’s mangrove species. Two globally threatened species, namely, Heritiera fomes and Sonneratia griffithii, are found to be present in India, in addition to Rhizophora x annamalayana Kathir., which is endemic to the Pichavaram mangrove in southeast India. In the last two decades, mangroves in India have been well maintained without any drastic changes, as a result of effective conservation measures being implemented in mangrove areas along the country, in spite of growing threats by man and natural calamities. What is required for the future of mangroves in India is restoration of ecosystem services of the mangroves with strong involvement of community participation to mitigate the impacts of climate change.

Astaxanthin level of dominant mangrove floral species in Indian sundarbans

Abstract: Astaxanthin level of dominant mangrove floral species in Indian sundarbansThe astaxanthin level in the leaves of five dominant mangrove species sampled from twodifferent stations of Sager Island in western Indian Sundarbans region was studied during April The two sampling stations selected at the northern and southern tips of theisland exhibited drastic variation with respect to aquatic salinity although other parameters like surface water temperature pH D O and nutrients were more or less uniform Relatively higher astaxanthin level was observed in the high saline zone southern tip of the island which indicates the regulation of astaxanthin level in the mangrove plants byambient aquatic salinity The inundated leaves of the selected mangrove plants showed more astaxanthin level in comparison to the exposed ones The astaxanthin content of themangrove leaves was in the order Heritiera fomes gt Avicennia alba gt Avicennia marina gt Avicennia officinalis gt Sonneratia apetala in both the sampling stations which points towards the species specificity of the carotenoid pigment

Impact of Aquatic Salinity on Mangrove Seedlings: A Case Study on Heritiera fomes (Common Name: Sundari)

Abstract: Mangroves are the characteristic littoral plant formation of tropical and subtropical sheltered coastlines [1]. Being on the land sea interface, they are always associated with and subjected to saline seawater. However saline condition is not a prerequisite for their development, rather mangroves choose saline condition to avoid the competition with the more vigorous terrestrial plants. Based on the physiological studies, Bowman [2] and Davis [3] concluded that mangroves are not salt lovers, rather salt tolerants. But excessive saline conditions retard seed germination, impede growth and development of mangroves. Indian Sundarbans, the famous mangrove chunk of the tropics is gradually losing Heritiera fomes (commonly known as Sundari) owing to increase of salinity in the central sector of the delta complex around the Matla River. Reports of alteration of growth in mangroves due to difference in salinity between western and central sectors of Indian Sundarbans are available [4]. However no study has yet been carried on the effect of salinity fluctuation on the photosynthetic pigments and carotenoid level of mangroves under culture conditions from this part of the Indian sub-continent. The effects of salinity on mangroves have been studied in relation to antioxidative enzymes [5,6], leaf structure, rates of transpiration, stomatal conductance and rates of photosynthesis [7,8] and changes in chloroplast structure and function [5,9]. Reported that Na+/H+ antiport catalyzed exchange of Na+ for H+ across the vacuolar membrane of the cells of Bruguiera sexangula offered tolerance to ionic stress imposed by NaCl and this mechanism was important for cellular salinity adjustments. Also, the mechanism of acclimation to salt in mangroves was suggested to be linked to the changes in the vacuolar size in B. sexangula [10]. Further, one of the biochemical mechanisms by which mangroves counter the high osmolarity of salt was accumulation of compatible solutes [5].

Utilization Pattern of Medicinal Plants by Different Tribes of Garo Hills of Meghalaya,North-East India

Abstract: Background: Hyperlipidemia is one of the leading causes of death in developed as well as in developing countries like Bangladesh. Hyperlipidemia is a major risk factor for early development of atherosclerosis and its cardiovascular complications. The objective of the study was to evaluate antihyperlipidemic, antiathersclerotic and cardio-protective activities of the leaves (LE) and aerial root (AR) extracts of Heritiera fomes (Family: Malvaceae, local name: Sundari) which is a common species in the world’s largest mangrove forest, Sundarbans, major part of which is located in Bangladesh. Methods and findings: Extracts of the powdered LE and AR of Heritiera fomes were obtained using methanol, and the extracts were applied at doses of 250 and 500 mg/kg of body weight, to treat the diabetic rats. Alloxan Monohydrate was used to induce diabetic condition in Sprague dawley rats. Metformin Hydrochloride was also used as a standard drug to treat the diabetic rats in order to compare the efficacy of the plant extracts with that of the standard drug. After 21 days of treatment, the animals were sacrificed and lipid profiles were estimated. The lipid levels were elevated in alloxan-induced diabetic rats as compared to the control rats. Total cholesterol, triglycerides, LDL and VLDL were increased in diabetic rats and the HDL level was significantly (P<0.001) decreased. After treatment with Heritiera fomes (LE and AR), the lipid levels of diabetic rats were returned to normal level and this reduction was dose-dependent, whereas HDL level was significantly (P<0.001) increased. LE and AR extracts also reduced atherosclerotic index and increased cardio-protective index as compared to the diabetic rats. Conclusion: Conventional drugs available for the treatment of hyperlipidemia carry the risks that may lead to many adverse effects such as weight loss, hypoglycemia, muscle pain, muscle damage, liver damage etc. So, medicinal plants having antihyperlipidemic, antiathersclerotic and cardio-protective properties should be given importance to avoid the adverse effects associated with modern allopathic lipid-lowering drugs. This study demonstrated that Heritiera fomes can be an excellent medicinal plant for the treatment of hyperlipidaemia, atherosclerosis and cardiovascular complications.

Spatial and temporal patterns of mangrove abundance, diversity and functions in the Sundarbans

Abstract: Mangroves are a group of woody plants that occur in the dynamic tropical and subtropical intertidal zones. Mangrove forests offer numerous ecosystem services (e.g. nutrient cycling, coastal protection and fisheries production) and support costal livelihoods worldwide. Rapid environmental changes and historical anthropogenic pressures have turned mangrove forests into one of the most threatened and rapidly vanishing habitats on Earth. Yet, we have a restricted understanding of how these pressures have influenced mangrove abundance, composition and functions, mostly due to limited availability of mangrove field data. Such knowledge gaps have obstructed mangrove conservation programs across the tropics. This thesis focuses on the plants of Earth’s largest continuous mangrove forest — the Sundarbans — which is under serious threat from historical and future habitat degradation, human exploitation and sea level rise. Using species, environmental, and functional trait data that I collected from a network of 110 permanent sample plots (PSPs), this thesis aims to understand habitat preferences of threatened mangroves, to explore spatial and temporal dynamics and the key drivers of mangrove diversity and composition, and to develop an integrated approach for predicting functional trait responses of plants under current and potential future environmental scenarios. I found serious detrimental effects of increasing soil salinity and historical tree harvesting on the abundance of the climax species Heritiera fomes. All species showed clear habitat preferences along the downstream-upstream gradient. The magnitude of species abundance responses to nutrients, elevation, and stem density varied between species. Species-specific density maps suggest that the existing protected area network (PAN) does not cover the density hotspots of any of the threatened mangrove species. Using tree data collected from different salinity zones in the Sundarbans (hypo-, meso-, and hypersaline) at four historical time points: 1986, 1994, 1999 and 2014, I found that the hyposaline mangrove communities were the most diverse and heterogeneous in species composition in all historical time points while the hypersaline communities were the least diverse and most homogeneous. I detected a clear trend of declining compositional heterogeneity in all ecological zones since 1986, suggesting ecosystem-wide biotic homogenization. Over the 28 years, the hypersaline communities have experienced radical shifts in species composition due to population increase and range expansion of the disturbance specialist Ceriops decandra and local extinction or range contraction of many endemics including the globally endangered H. fomes. Applying habitat-based biodiversity modelling approach, I found historical tree harvesting, siltation, disease and soil alkalinity as the key stressors that negatively influenced the diversity and distinctness of the mangrove communities. In contrast, species diversity increased along the downstream – upstream, and riverbank — forest interior gradients, suggesting late successional upstream and forest interior communities were more diverse than the early successional downstream and riverbank communities. Like the species density hotspots, the existing PAN does not cover the remaining biodiversity hotspots. Using a novel integrated Bayesian modelling approach, I was able to generate trait-based predictions through simultaneously modelling trait-environment correlations (for multiple traits such as tree canopy height, specific leaf area, wood density and leaf succulence for multiple species, and multiple environmental drivers) and trait-trait trade-offs at organismal, community and ecosystem levels, thus proposing a resolution to the ‘fourth-corner problem’ in community ecology. Applying this approach to the Sundarbans, I found substantial intraspecific trade-offs among the functional traits in many tree species, detrimental effects of increasing salinity, siltation and soil alkalinity on growth related traits and parallel plastic enhancement of traits related to stress tolerance. My model predicts an ecosystem-wide drop in total biomass productivity under all anticipated stress scenarios while the worst stress scenario (a 50% rise in salinity and siltation) is predicted to push the ecosystem to lose 30% of its current total productivity by 2050. Finally, I present an overview of the key results across the work, the study’s limitations and proposals for future work.

Anti-Obesity Potential of Heritiera Fomes Leaves Methanolic Extract in a Preclinical Model

Abstract: Objective: This study was undertaken to evaluate the anti-obesity potential of the methanolic extract of leaves of Heritiera fomes. (MEHF) in high fat cafeteria diet (HFCD) fed obese rats. Methods: Wistar strain of albino rats were divided into six groups comprising of six rats each. Group I served as normal control fed with normal pellet chow, group II served as disease control fed with high fat cafeteria diet, group III, IV and V animals, received MEHF at a dose level of 100, 200 and 400mg/kg b.w along with HFCD for 40 days, while, group VI served as standard drug control, which received Orlistat at a dosage of 50mg/kg b.w along with HFCD. Results: Administration of HFCD for 40 successive days to experimental rats significantly increased the body weight, organ and fat pad weights, serum total cholesterol, LDL cholesterol, VLDL cholesterol, triglycerides and glucose levels; and decreased HDL cholesterol as compared to normal control. While treatment with MEHF showed a significant reduction in the body weight gain, organ weight of the liver, kidney, spleen, weight of fat pads and the levels of serum triglycerides, total cholesterol, LDL cholesterol, VLDL cholesterol, glucose and increase in HDL cholesterol in a dose dependent manner. Further, the levels of liver markers such as aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP), which were found to be elevated in the serum of obese rats, also resumed to normal on treatment with different concentrations of MEHF. Moreover, the consumption of MEHF reduced oxidative stress by enhancing the levels of glutathione (GSH), glutathione peroxidase (GPx), super oxide dismutase (SOD) and catalase in the hepatic tissue of rats with HFCD induced obesity. Conclusion: These results demonstrate clearly that repeated oral administration of Heritiera fomes methanolic extract can evoke a potent anti-obesity activity.

Nesting Ecology and Habitat Preference of the Masked Finfoot (Heliopais personatus) in Sundarbans, Bangladesh

Abstract: The Masked Finfoot (Heliopais personatus) has a global population estimated at 1,000 individuals, but very little is known about its ecology. Therefore, the nesting ecology of the Masked Finfoot was studied in the Sundarbans of Bangladesh between 2011 and 2014, and compared to nesting observations from the same area made in 2004. A total of 25 nests were detected in 2011–2014: 56% (n = 14) on blinding mangrove (Excoecaria agallocha), 36 % (n = 9) on sundri (Heritiera fomes) and 8% (n = 2) on cannonball mangrove (Xylocarpus granatum). Factor analysis revealed that 2004 nest characteristics differed from subsequent years. The 2011–2014 nests were built on the periphery of vegetation along narrow creeks of 12.66 ± 3.54 m and located 1.78 ± 0.53 m above water level at high tide. Diameter of nesting tree (2004 = 16.68 ± 5.82, 2011–2014 = 34.19 ± 3.96), nest depth (2004 =16.88 ± 3.09, 2011–2014 = 13.28 ± 3.32) and creek width (2004 = 21.26 ± 9.09, 2011–2014 =12.66 ± 3.54) was significantly different between 2004 and 2011–2014. Reasons for changes in nesting locations are important to determine given the conservation status of the species and altering conditions in the Sundarbans.