Search

Banyuwangi is an area that has the longest coastline in East Java, with a length of 175.8 km. one of the coastal potentials is the mangrove ecosystem. Pantai Sari is one of the locations that has the potentials to be developed in Banyuwangi regency. This beach is a forest area in the city of Banyuwangi. In general, they have natural charateristics, many pine trees have been planted since 2015. The purpose of this study was to obtain data on the diversity of mangroves in river and coastal areas at Pantai Sari. The method used is descriptive quantitative, with data collection using nested plot method with a distance of 20 m between plots. The results showed that there are 7 species mangroves were found in the river, namely Avicennia officinalis , Rhizophora apiculata , Sonneratia caseolaris , Lannea coramandelica , Erythrina costaricensis , dan Thespesia populnea . The highest number of individuals was Rhizophora apiculata with number 1,291 individu, and the lowest number was Erythrina costaricensis and Thespesia populnea . The other hand, there was 5 species mangroves in the coastal area, namely Casuarina cunninghamiana , Casuarina equisetifolia , Lannea coramandelica , Terminalia catappa , dan Thespesia populnea . The highest number of individuals was pine beach ( Casuarina equisetifolia ) with number 122 individu, and the lowest number was waru laut ( Thespesia populnea ) with number 1 individu

In a tropical coastal environment, mangrove ecosystems store large amount of atmospheric carbon in biomass and soil. West coast of India host 29% of the mangrove ecosystems of the country. Putting aside the few scientific studies about the Indian mangroves system, there exist gaps in our scientific knowledge of Blue Carbon domain. This study aims to quantify the ecosystem carbon stocks potential and community structure of mangrove vegetation/ ecosystem species of Vypin– Cochin, a coastal region of the Southwest coast of India. The information on species-specific carbon storage will benefit to choose best species in the afforestation and conservation initiatives. Distribution, community structure and carbon pools of above and below ground biomass of the study area were assessed. From the analysis, it is evident that the amount of carbon stored in mangroves varies according to species, functional attributes (basal area, DBH, mean height etc.) and region. Avicennia officinalis, Rhizophora mucronata, Acanthus ilicifolius, Acrostichum aureum, Bruguiera cylindrica and Sonneratia caseolaris are the mangrove species observed from the study area. As per the community structure assessment, A. officinalis showed large number, frequency, density, and evenness. While considering biomass, R.mucronata species possess high value. The mean overall above ground biomass of the region was 69.55 ± 80.38 t ha−1. Ecosystem carbon stock of the area ranges from 17.7–138.8 with an average of 54.3 ± 36 t ha−1. Therefore, the findings described will serve as a baseline on carbon stock and mangrove stand structure of the region and their role in Blue Carbon dynamics of the Southwest Coast of India.

Mangroves adaptive plasticity in the changing environmental conditions is of vital importance for conservation management. Genetic diversity of mangrove brings about adaptive plasticity, enabling a species to cope with different habitat conditions. The Sundarbans of Bangladesh is the largest coastal wetland and mangrove forest with diversified habitat conditions that support a wide diversity of flora and fauna. Avicennia officinalis L. is the pioneer species in mangrove succession in the low-salinity, medium-salinity and high-salinity zones of the Sundarbans. Adopting RAPD-PCR analysis, the genetic diversity of A. officinalis was studied to explore the ecotypes of this species in the Sundarbans. The genetic distances of A. officinalis between the low-salinity and medium-salinity zones (0.50) and between the low-salinity and high-salinity zones (0.52) are significantly (p

Naturally grown mangrove forest is the south coastal community’s green barrier from any type of hydro-meteorological hazard and disasters. South-western coastal area of Bangladesh is covered by the Sundarbans, and mid-central zone is covered by Tengragiri wildlife sanctuary which is taken as a protected area in this recent era but not mapped properly with considering different species diversification and temporal changes pattern which is required for successful co-management of this mangrove forest. This study identifies species composition, plant diseases, degradation of the mangrove forests and further focuses on mapping mangroves by conducting plotting-based primary field visit, variability analysis using different indices and cross-matching with secondary databases. Existing mangrove forest boundary’s 200 m buffering with three-time series satellite imagery 2000, 2010 and 2017 is considered for further analysis. Including all buffering zone, this protected area considered 9 major classes that included four subclasses for presenting result like Baen (Avicennia officinalis), Gewa-Goran (Excoecaria agallocha, Ceriops decandra), Keora (Sonneratia apetala), Sundri (Heritiera fomes), Plantation trees Samanea Saman (Raintree), agriculture-grassland (agri-grass) and homestead settlement, sandbar and waterbody. Mapping accuracy assessment purpose automatically generated 996 points cross-matched with previously mangrove species level detailed survey results and found highest accuracy in Sundri species (70%) and all others above 50%. During 2000–2017, the Keora area showed the highest increase 129% over 2000 and increasing rate 13.17 ha/yr. About 26% Sundri and Baen–Passur increased around 13.45 ha/yr. In case of Sundri, 70% area coverage remained intact during 2000–2017, while other 25% classified in 2017 as Avicennia officinalis, Gewa-Goran classes. Furthermore, using refracted electromagnetic energy from various physical characteristics of plants application, four indices (NDVI, DVI, MSAVI-2, RVI) are usable where single-species-level crop density analysis has limitations, but identification of Sundri and Keora by MSAVI-2 and NDVI found significant and alternately lower accuracy values from RVI. Identification of dominant mangrove species groups as well as area gains and losses over 2000–2017 is a robust biophysical baseline for management of the sanctuary. Natural hearts of this area and working as first-step warriors against natural disasters originated from Indian Ocean and Bay of Bengal; so far, it is very much required to save this forest and the coastal communities as well. The results of the study and maps will be helpful for the scientific community, planners, government-international bodies and the activists, Forest Department and the local community in effective planning, monitoring the effectiveness of co-management in conservation of the sanctuary.

In Myanmar’s Ayeyarwady Delta, mangrove forests were widely converted to paddy fields, then abandoned. However, the mangrove ecosystems often fail to recover. To identify the mangrove restoration options in these fields, we conducted the current study in Pyindaye Forest Reserve, Pyapon Township of the Delta by examining the structural and functional responses to restoration for two common mangrove species (Avicennia officinalis and Bruguiera sexangula) after three post-abandonment periods (4, 8, and > 10 years), the natural recovery after these periods, and management to improve degraded forests dominated by the two species. Without replanting, we observed no mangrove cover or regeneration more than 10 years after abandonment. The sites were dominated by a perennial grass (Paspalum vaginatum), sparse climber, herbs, and spiny shrubs. With increasing the abandoned period, we observed decreasing soil quality and increasing vegetation cover by the grass, herbs, and spiny shrubs in response to increasingly harsh micro-environmental conditions for natural recovery of mangrove. Without human assistance, the abandoned paddy fields will not recover their productivity after more than 10 years. However, with increasing the period of establishing mangrove plantations in the abandoned fields, the ecosystem showed improved vegetation structure and regeneration of both planted and non-planted species. The soil conditions improved during mangrove recovery, and a well-developed canopy and aerial root system developed. By 8 years after mangrove establishment, the land could be used again as paddy fields due to suppression of P. vaginatum and the improved micro-environment. The managed forests showed the best structural attributes, conditions for regeneration, and micro-environmental conditions for plant growth and regeneration. Our results suggest three options for managing the abandoned paddy fields: paddy cultivation based on fallow periods with mangrove establishment, mangrove planting for wood production, and mangrove planting for environmental restoration.

The mangroves of Andaman and Nicobar Islands are considered as one of the finest vegetation in India with respect to species composition as well as structure. However scientific information on the influence of edaphic attributes on the structure of Andaman mangroves are lacking. Hence, we assessed the floristic composition, structural attributes, zonation pattern and its relation to edaphic variables of mangroves of the Andaman islands. Quadrat method was employed to estimate the different structural variables and multiple regression analysis to explain the influence of edaphic variables over structural attributes. Floristic analysis of 420 quadrats (10x10m) revealed a mixed species composition with 28 true mangroves in Andamans, of which Avicennia officinalis, Rhizophora apiculata, and R. mucronata were designated as the most important species based on the importance value index. Stem density varied from 133 to 14,000 ha−1 and individual basal area 0.07–78.75 m2 ha−1, further, most of the mangrove habitats showed very high stand basal area. Relatively higher Maturity Index Value was observed indicating high structural maturity in Andamans. Species zonation pattern typically varies based on the tidal inundation. Multiple regression analysis revealed the importance of soil pH, silt, total carbon, total Nitrogen and salinity in shaping the structure of Andaman mangroves. The data evolved in the study would be valuable in the site-specific management and conservation approaches of mangroves in Andamans.

Mangrove sediment acts as a natural accumulator of potentially toxic metals (PTMs). Here, we have investigated the efficiency of mangrove species, e.g., Sonneratia caseolaris and Avicennia officinalis phytoremediation potential in a globally significant vulnerable river. The lower pH and anoxic conditions facilitate the elevated accumulation of PTMs in river Hooghly. The presence of PTMs in fine sediment fraction in greater proportion indicates a larger role of fine-grained silt and clay particles in the accumulation process. The estimated sediment quality indices indicate no significant change in the last 30 years. However, the ecotoxicological indices suggest a low level of ecological risks but can turn toxic because of the gradual accumulation of metals. The accumulations of PTMs in mangroves are regulated by the metal bio-availability. The result emphasizes mangrove pneumatophores, as a greater accumulator of PTMs than mangrove leaves. Higher translocation factors also indicate the applicability of mangroves as a phytoremediator of contaminated sediment.

Natural ecosystems are highly dynamic and exhibit a highly nonlinear nature. We attempt to detect and analyze changes in a coastal mangrove ecosystem to predict the dynamics of the system and its biodiversity. Multitemporal hyperspectral data have been used to analyze the competition among mangrove and saline blank endmembers and their dominance with time. We aim to predict the ecodynamics of the area through subpixel analysis of multitemporal hyperspectral imagery. The biodiverse coastal zone of Sunderban Biosphere Reserve, West Bengal (a world heritage site), is considered as a case study for predicting the mangrove ecodynamics of the area through Markov chain analysis. The mangrove species of Sunderban vary in their abundance with time due to dynamic weather conditions. The model is applied to hyperspectral data from 2011 and 2014, collected over Henry Island in the Sunderban to predict species dynamics in 2017 and 2020. An endmember transition matrix is framed to determine the endmember dynamics in the area in terms of degradation and regeneration of mangroves and saline blank cover in the area. Based on the transition probability matrix, the abundance values have been predicted for 2017 and 2020. The predicted abundance values have been validated by ground truth values extracted during field visits in 2017. It is observed that, in certain locations, the increase in saline blanks has led to an overall decrease in the proportion of Phoenix paludosa and Ceriops decandra (a salt-intolerant mangrove species) over the years. However, there is an increase in Avicennia marina and Avicennia officinalis, which are salt tolerant and can sustain in extreme saline conditions.

An experiment was conducted to assess the effect of NPK fertilizers on seedling growth and survival of five important mangrove species of Bangladesh for nine months. Seedlings were raised in the nursery using plastic pots. NPK fertilizers with three treatments (control, 4 gm and 8 gm doses) were used two times when seedlings age was 3 and 6 months. The result showed that seedlings height growth of Excoecaria agallocha was enhanced significantly with the application of NPK fertilizers but it was shown negatively significant effect on height growth of Xylocarpus mekongensis after second time fertilizer application. Moreover, NPK application enhanced mortality of Avicennia officinalis and Ceriops decandra seedlings in both times of fertilizer application. But no effect of NPK fertilizers on seedlings growth and survival of Heritiera fomes were observed.

Mangrove forests are ecosystems that make up coastal areas and river estuaries. The examples of mangrove ecosystems found in Indonesia are in Segara Anakan, Central Java. One of the aquatic biota with the economic value found in the mangrove forest ecosystem is the mud crab (Scylla spp.). The purpose of this study was to assess the distribution of mangrove crabs (Scylla spp.) to the presence of mangrove species in the mouth of the Donan River, Segara Anakan. A sampling of crabs and observations of mangrove vegetation were carried out at five stations spread from the river to the sea. The results showed that there were three types of mangrove crabs caught in the vicinity of the study, namely Scylla tranquebarica, S. olivacea, and S. serrata. The types of mangroves found include Rhizophora apiculata, R. mucronata, Avicennia rumphiana, A. alba, A. officinalis, and Nypa. Regression analysis showed that mangrove density correlated with the abundance of Scylla tranquebarica and Scylla olivacea, but contradicts the abundance of Scylla serrate. PCA analysis showed that the Crab species Scylla tranquebarica and Scylla olivacea were associated with mangroves of Avicennia alba, Avicennia rumphiana, and Rhizophora apiculata. Meanwhile, Scylla serrata crabs are associated with Avicennia officinalis.

The species composition and geospatial distribution of coastal ecosystems such as mangroves, mudflats, filtration ponds, backwaters, and so on and their associates in the southwest coast of India are studied through field mapping using high-precision GPS and incorporating information extracted from high-resolution world-view satellite images. Appropriate management strategies to protect and restore the mangrove and mudflat ecosystems under the provisions of Coastal Regulation Zone (2011) (INDIA) are discussed. The Kerala coast, located at the southwest peninsula of India, has one of the longest densely populated rural–urban agglomerated coastal plains in India. Being one of the highly populated states of India, its low-lying coastal areas (2.42% of its total geographical area) includes 8.25% of its total population, with an average coastal density of 2931/ km2. Kerala coastal plains were reported for 10 exclusive mangrove species: Avicennia officinalis, Avicennia marina, Rhizophora mucronata, Sonneratia alba, Acanthus ilicifolius, Excoecaria agallocha, Bruguiera gymnorrhiza, Lumnitzera racemosa, and Kandelia candel, Barringtonia are reported in the study area. Mangrove coverage in the Alappuzha district of Kerala is 1.43 km2. Spread of mangroves in the two major urban centers, Kochi corporation, Maradu municipality, and adjoining Vembanad, is 0.48 and 0.40 km2, respectively. Coverage of mangroves in Ashtamudi and a few other backwaters is 0.95 km2. Reclamation and destruction of coastal ecosystems have been taking place on a large scale in the urban areas of Kochi corporation and Maradu municipality. Proper intervention through a sustainable management plan like the Coastal Regulation Zone Notification of India will address the issue of conserving the mangroves and associated eco-morphological systems.

Shrimp based mangrove-aquaculture (silvo-aquaculture) is practiced in many countries of the world and leaf litter of different mangrove tree species is a potential nutrient source in these systems. The present study evaluated the effects of mangrove leaf litter from four mangrove species (Sonneratia apetala, S. caseolaris, Avicennia officinalis and Heritiera fomes) on the production of juvenile shrimp (Penaeus monodon) with and without supplemental feed. Fifteen-day-old post larvae (PL15) with an average weight of 0.01 g were reared in 1100 L fibre-reinforced polyethylene tanks containing 1000 L of 10 ppt saline water and a water depth of 0.9 m. Leaf litter with or without supplemental feed was applied to the tanks according to a 4 × 2 factorial design. The PLs were stocked at a density of 100 per tank and the experiment was conducted for 4 weeks without any exchange of water. Both mangrove species and feed application affected shrimp performance and water quality parameters except dissolved oxygen (DO), chemical oxygen demand (COD) and zoo-plankton concentration. The average survival rate of juvenile shrimp ranged from 86 to 94% in the treatments with both leaf litter and feed, 75–82% in the treatments with only leaf litter and 88% in the treatment with only feed. However, 100% mortality was observed in the treatment without any leaf litter or supplemental feed. Combined, leaf litter and feed resulted in 21 to 33% higher weight gain of shrimp PL than based on the combined contributions of leaf litter only or feed only, indicating synergism. Among the different mangrove species, S. apetala (23.1%) contributed the highest to total weight gain followed by A. officinalis (21.6%), S. caseolaris (21.6%) and H. fomes (10%). The lower feed conversion ratio (FCR) (0.18–0.27) in the treatments combining leaf litter and supplemental feed as compared to the feed-only treatment (0.41) indicated that leaf litter (directly or by stimulating natural food production) contributed to supplemental feeding. The growth of phytoplankton also appeared to contribute in low FCR as evidenced by a positive correlation (P < 0.001, r = 0.681⁎⁎) between phytoplankton concentration and shrimp weight gain. The synergistic effect between leaf litter and supplemental feed can help the farmer to minimize the shrimp production cost by lowering the feed input and enhancing mangrove three coverage on pond dikes as an inexpensive source of natural food.

Urban development is driving the loss and subsequent fragmentation of mangrove forests in Penang, Malaysia. However, little research has focused on the implications of urbanization onto the biodiversity within mangrove forests. This study investigates and compares both vegetation and crab assemblages between urban and rural mangrove forests. Collectively, 5853 trees were recorded including 15 species from six families: Acanthaceae, Arecaceae, Lythraceae, Malvaceae, Meliaceae, and Rhizophoraceae. Avicennia marina accounted for 88.6% of all trees in the study and held the highest species importance (IV). Although the total number of mangrove tree species varied significantly between urban (14) and rural (7) mangrove forests, the mangrove forest structure based on IV did not vary significantly. In total, 633 crabs were recorded comprising 13 different species from three superfamilies: Grapsoidea, Ocypodoidea, and Paguroidea. Crab species richness did not vary between urban and rural sites, but the biomasses of five and the densities of four crab species varied significantly. Redundancy analysis (RDA) indicated that land use, salinity, and abundance of Avicennia officinalis can best describe the distribution of crab species (r2 =32.7). This study indicates that smaller fragmented urban mangroves at the east coast of Penang have a relatively high tree and crab diversity and are worth protecting, in addition to the larger mangrove forests on the west coast. The preservation of small yet interconnected mangrove sites could be critical to the recruitment of their flora and fauna and should be considered in decision-making processes.

Salinity is an environmental stress that causes decline in crop yield. Avicennia officinalis and other mangroves have adaptations such as ultrafiltration at the roots aided by apoplastic cell wall barriers to thrive in saline conditions. We studied a cytochrome P450 gene from A. officinalis, AoCYP94B1, and its putative ortholog in Arabidopsis (Arabidopsis thaliana), AtCYP94B1, which are involved in apoplastic barrier formation. Both genes were induced by 30 min of salt treatment in the roots. Heterologous expression of AoCYP94B1 in the atcyp94b1 Arabidopsis mutant and wild-type rice (Oryza sativa) conferred increased NaCl tolerance to seedlings by enhancing root suberin deposition. Histochemical staining and gas chromatography-tandem mass spectrometry quantification of suberin precursors confirmed the role of CYP94B1 in suberin biosynthesis. Using chromatin immunoprecipitation and yeast one-hybrid and luciferase assays, we identified AtWRKY33 as the upstream regulator of AtCYP94B1 in Arabidopsis. In addition, atwrky33 mutants exhibited reduced suberin and salt-sensitive phenotypes, which were rescued by expressing 35S::AtCYP94B1 in the atwrky33 background. This further confirmed that AtWRKY33-mediated regulation of AtCYP94B1 is part of the salt tolerance mechanism. Our findings may help efforts aimed at generating salt-tolerant crops.

Sabdanawaty FP, Purnomo, Daryono BS. 2021. Species diversity and phenetic relationship among accessions of api-api (Avicennia spp.) in Java based on morphological characters and ISSR markers. Biodiversitas 22: 193-198. Api-api (Avicennia spp.) from mangrove groups is rich in economic and ecological benefits. Research on the potential of api-api has been extensively done, but no research is specifically focused on the identification of api-api. This study aims to identify species diversity and phenetic relationships of api-api in Java based on morphological and molecular characters. The morphological analysis was based on 35 characters and referred to the descriptor. The PCA analysis on the morphological characters of Avicennia spp. showed a high diversity. Morphological characters have a high effect on grouping patterns such as habitat, leaf shape, leaf tip, leaf base, and petal color. Molecular observations were done on the polymorphism of DNA bands. The ISSR primers used were ISSR02, ISSR04, and ISSR10. PCR amplification of DNA was separated and visualized using a doc gel electrophoresis. The results showed a high diversity based on the percentage of DNA polymorphism. The research resulted in three species of Avicennia spp. in Java, namely Avicennia officinalis, A. alba, and A. marina. Phenetic relationships between Avicennia spp. form was based on similarity in character, not based on the area of origin. The environmental conditions in this study slightly opposed the character of Avicennia spp., which presumably due to the similarity in various marine areas of Java such as temperature, pH, and the required salinity.

Mangroves are distributed along both the east and the west coasts of India, with more diversity reported from the west coast. More than 414 fungal species belonging to around 226 genera have been reported from the mangroves of India. The majority of them (325 species in 189 genera) belong to Ascomycota, and of those remaining, 35 species in 28 genera belong to Basidiomycota, and 54 species in 10 genera belong to Zygomycota. More than 80% of these fungi could be considered as obligate marine fungi, whereas several facultative marine fungi that are normally recorded from terrestrial environments were also recorded. While 306 fungi belonging to 170 genera were recorded from mangroves of the Indian west coast, 225 species in 131 genera were recorded from mangroves of the east coast. Of the 414 fungi reported from mangroves, 117 species in 75 genera were common to both the east and the west coasts. A total of 108 species in 56 genera were reported just from the east coast Indian mangroves. Likewise, a total of 189 species in 95 genera were recorded just from the west coast of Indian mangroves. From Zygomycota, Glomus was found to be the most speciose genus, having 20 species. Among the different fungal genera of Ascomycota, Corollospora is represented with 13 species, followed by Aspergillus and Aniptodera with 11 and 9 species, respectively. Phaeosphaeria, Leptosphaeria, and Lulworthia are represented with eight species, while many other genera of this group were recorded with fewer species. Among the anamorphic genera, Cirrenalia is found to be represented with six species. Among the different mangrove host plants prevailing in India, Rhizophora mucronata exhibited a large fungal species diversity, followed by Avicennia officinalis, A. marina, and Rhizophora apiculata. Moderate diversity has been reported on Brugueira gymnorrhiza, Sonneratia caseolaris, while other plants, such as Acanthus ilicifolius, Avicennia alba, Ceriops decandra, and so on, have shown a very low fungal diversity.

The purpose of this work was to assemble information with which to help identify and select mangrove species most likely to be useful and locally acceptable for use in transforming the dominant current non-mangrove shrimp culture practice in Bangladesh towards more sustainable shrimp silvo-aquaculture in the coastal regions of the country. We reviewed current mangrove use in the extensive aquaculture setting, compiled published evidence on mangrove properties and characteristics that influence their suitability for such use and assessed farmer preferences of the various species. Thirteen mangrove species (all of which are available in Bangladesh) were documented as being used in silvo-aquaculture system in the tropics. Followed by these already “established” mangrove species, Aegialitis rotundifolia, Heritiera fomes and Lumnitzera racemosa could be enlisted as additional “optional” mangrove species to consider, while Ceriops decandra, Excocaria agallocha and Phoenix paludosa were found to be unsuitable for silvo-aquaculture. Based on their experience and indigenous knowledge on mangroves, shrimp farmers ranked (in declining order of preference) Sonneratia apetala, S. caseolaris, Avicennia officinalis, Nypa fruticans, Bruguiera sexangula, Heritiera fomes, and also, the mangrove-associate wild rice species Oryza coarctata as the most suitable species to be used for promoting silvo-aquaculture in the coastal areas of Bangladesh. Thus, the focus group interviews with the farmers not only identified which mangroves enjoy most local support for use in transforming current shrimp culture towards more sustainable shrimp silvo-aquaculture but also provided additional leads for species interesting to further investigation into their suitability for silvo-aquaculture.

The ability of mangrove trees to reproduce and disperse in highly dynamic tidal environments is reflected in the contemporary genetic diversity and structure of their populations. Resilience and establishment may occur through either local recruitment (propagule pool model) or over longer distances with mixed origins (migrant pool model), thereby affecting the connectivity between natural populations. Anthropogenic activities such as encroachment and fragmentation or from mitigating reforestation could cause strategy switches and thus the connectivity and genetic structure of populations. In this study, we considered Avicennia officinalis, a dominant component of the Sundarban mangrove forest in Bangladesh to estimate dispersal dynamics over various distances within estuaries. A total of 423 individuals of A. officinalis, distributed over thirteen sites in the Sundarbans were sampled at both large and fine-scaled spatial level, the latter for comparison of natural and dense with fragmented sites. Up to 62 alleles showed a comparable level of allele diversity and gene diversities at both juvenile and adult life stages, assuming overall high levels of outcrossing. Significant inbreeding levels and high kinship values were solely observed at a reforested A. officinalis site. Genetic variables revealed high levels of connectivity between sites at close vicinity, with only a weak structure over larger geographic distances, between natural core Sundarban and coastal edge populations. Kinship coefficients were mostly low though significant up to several kilometers along estuarine branches, thereby suggesting propagule dispersal beyond each site. A fine-scaled analysis of kinship levels estimated for fragmented and natural forest plots along both sides of a river revealed that fragmentation induced higher kinship levels over 25–50 m distance, whereas dense natural populations were composed of less related individuals at shortest distances. A. officinalis populations might stay resilient through a mixture of unrelated propagules, clearly adhering a migrant pool model in natural sites and propagule pool model in fragmented sites. A poor gene diversity of planted trees might jeopardize the sustainability of mangrove plantation practices. Furthermore, high levels of diversity and connectivity indicated that the core Sundarban populations are a relevant source of germplasm in afforestation programmes.

Basyuni M, Sagami H, Baba S, Oku H. 2019. Response of polyisoprenoid concentration and profile in three groups of mangrove seedlings of coping with long-term salinity. Biodiversitas 20: 320-326. The response of polyisoprenoid (polyprenol and dolichol) concentration and distribution was investigated with three groups mechanism of coping with salinity: a secreting mangrove species of Avicennia officinalis, a non-secreting species (excluder) of Bruguiera cylindrica, and a salt-accumulating species of Xylocarpus granatum. The seedlings of three mangroves were grown under 0 and 3% salinity concentration for five months. Polyisoprenoids in the lipid extracts were examined by two-dimensional thin layer chromatography (2D-TLC). The pattern of the polyprenols and dolichols in the leaves and roots were categorized as two types (I and II). In category I, dolichols dominated over polyprenols, however, in category II, the existence of both polyprenols and dolichols was found. In the leaves, type-I was observed in A. officinalis under 0 and 3% salinity. On the other hand, type-II was found in B. cylindrica and X. granatum under 0 and 3% salt concentrations. A similar pattern was found in the roots, A. officinalis (type-I), and that in B. cylindrica and X. granatum was type-II. This finding depicted that the seedlings of A. officinalis, B. cylindrica, and X. granatum leaves and roots imply no change in the distribution type: the categories were distributed as type I or II under 0% salt concentrations, as well as type-I or II under 3% salt concentrations. This study implied that polyisoprenoids may play a protective function against salinity in the mangrove leaves and roots of three groups scheme (secreting, excluding, and accumulating) of salt management.

Nutrient resorption efficiency is an important nutrient conservation and ecophysiological mechanism of mangroves growing in saline environments. This study investigated the nitrogen, phosphorus, and potassium resorption efficiency of Avicennia officinalis L. growing across a salinity gradient with seasonal variations in the Sundarbans of Bangladesh. Due to decreasing salinity during the monsoon and postmonsoon seasons, the nutrient availability in soil and nutrient resorption efficiency did not vary significantly among the low-salinity, medium-salinity, and high-salinity zones. However, the nutrient availability in the medium-salinity and high-salinity zones was significantly lower than that in the low-salinity zone during the premonsoon season due to increased salinity. Consequently, nutrient resorption efficiency in the medium-salinity and high-salinity zones was significantly higher than that in the low-salinity zone during the premonsoon. Further, leaf vein density of A. officinalis in the medium-salinity and high-salinity zones was significantly higher than that in the low-salinity zone. This modification in vein density was the mechanism for the higher nutrient resorption efficiency of A. officinalis in the medium-salinity and high-salinity zones than that in the low-salinity zone. This plasticity in nutrient resorption efficiency is a physiologically adaptive mechanism that enables A. officinalis to persist in increasingly saline environments due to climate change.

Spatial distribution of potentially toxic metals (PTMs) and their accumulation in mangrove Avicennia officinalis L. were studied along 8 locations in and around Sundarban mangrove wetland, India. Among 8 locations, S3 (Chemaguri) and S5 (Ghushighata) showed higher concentration of PTMs (Cd, Cr, Cu, Ni, Pb, Zn) characterized by higher enrichment factors (3.45-10.03), geo-accumulation indices (0.04-1.22), contamination factors (1.14-3.51) and pollution load indices (1.3-1.45) indicating progressive deterioration of estuarine quality and considerable ecotoxicological risk. Metal concentration in A. officinalis leaves showed significant correlation with sediment metals implying elevated level of bioaccumulation. Significant statistical correlation between photosynthetic pigments (Chlorophyll a, Chlorophyll b), antioxidant response (free radical scavenging and reducing ability) and stress enzymatic activity (Peroxidase, Catalase, Super-oxide dismutase) of A. officinalis with increasing metal concentration in the contaminated locations reflects active detoxification mechanism of the plant. The study indicates the potentiality of biomonitoring metal pollution using studied biochemical markers in mangrove habitats.

This aim of the research is to know the condition of the ecology of mangrove forests in the Waisai Raja Ampat District, West Papua. This research was carried out during the year, from April 2012-April 2013. Research locations include three (3) stations which were Moko, Kimindores and the tourist port area. The method was line transect with quadratic plot along a 100-meter at the seaside. The plots were created in size of 1 x 1m 2 ; 5 x 5 m 2 ; 10 x 10 m 2 and 20 x 20 m 2 . The observations showed that there were 8 types of mangrove in the town of Waisai consisting of Avicennia officinalis, Sonneratia alba, Rhizophora stylosa, R. mangle, R. mucronata, Aegricecas floridum, Bruguiera gymnnorhiza , and Nypa fruticans. The distribution of mangrove types in Waisai is spread unevenly. A. floridum was found only at Moko; R. mucronata was at the area of the tourist Port only; and Nypa has a wider distribution since they were found at the three stations of observations. Key words : biota, diversity, mangrove, Raja Ampat.

In a mangrove environment, several groups of organisms are symbiotically associated with pneumatophores (aerial roots). But whether these organisms are exclusively found in this habitat (uniqueness) or accidentally settled here from water or sedimentary habitat, is not clearly understood. This hampers our understanding of their functional ecology. Hence the present study aimed to characterise the epibiotic microalga and meiofauna from the pneumatophores of mangrove Avicennia officinalis . To determine the habitat influence, these communities were also compared with those found in water and sedimentary habitat. Four estuarine mangrove sites represented by brackish water (salinity varying from 5 to 12) and located at different spatial scales (5–50 km distance) were chosen to determine whether these communities are consistent or vary with sites. Overall, the microalgal community was found to vary both among the habitats as well as sites. In the pneumatophore habitat, several tychoplanktons such as Coscinodiscus, Thalassionema , Cyclotella, Fragilariopsis, and Biddulphia were observed instead of benthic ones. These diatoms are planktonic genera and might have settled on pneumatophores from the water column. The observed variability in the microalgal composition among the sites is possibly due to predatory interactions or the dominance of particular species of macroalga that govern the diatom community. On the other hand, among the meiofaunal community, diptera, halacarida, tanaidacea, and foraminifera were mainly found in the pneumatophore habitat than in the sediment. Because pneumatophores either provide refugee to meiofauna against predators or are saturated with oxygen that meiofauna can utilize for respiration. Pneumatophores were also found to harbour several rare (abundance

Elevated human-induced activities have prompted significant uncontrolled release of potentially toxic metals (PTM) to the undisturbed ecosystem throughout the globe. Riparian mangrove vegetations act as a natural purifier of wastewaters and assist in maintaining a healthy ecosystem. We have investigated the elevated PTM-induced stress and biotic response of two riparian mangrove species e.g. Sonneratia caseolaris and Avicennia officinalis by river Hooghly. The increased PTM concentrations were observed throughout the river bank; with the maximum pollution load at Chemaguri (S9). Except Co, Cr and Pb, higher enrichment factor (1.97–8.89) and contamination factor (0.64–2.88) values were observed for Cd, Cu, Fe, Zn. Mn, and Ni. Geo-accumulation index (−2.2 – 0.92) values indicates natural geogenic accumulation of Cu in the riparian mangrove sediment. Thus, sediment quality indices suggest except Cu, enrichment of all studied PTMs was sourced from anthropogenic activities. The sediment of the region when compared with consensus-based sediment quality guidelines shows considerable ecotoxicological risks and threat towards human health considering Ni accumulation. The highest potential ecological risk index value was observed in Chemaguri (S9). The biotic response of riparian mangroves was characterized by reduced photosyhthetic pigments (Chlorophyll a and Chlorophyll b) and increased activity of antioxidative stress enzymes (POD, CAT and SOD). Significant statistical relationship between antioxidative enzyme activity, photosynthetic pigments and bioaccumulated PTMs reflects active functioning of detoxification mechanism in the riparian mangrove species.

Variations in stem biomass and carbon density in 12 mangrove species were studied to understand the potential of carbon storage in the live biomass of Bhitarkanika mangrove ecosystems, South-East Coast of India. The results highlighted significant inter-species variations (p C org / N tot ratios followed by Heritiera fomes. Further, the higher carbon sequestration capacity of these two mangrove species was confirmed through Principal Component Analysis (PCA). C org , C org / N tot and cellulose/protein ratio were strongly associated with the wood density of the studied mangrove species. Mangrove stem diameter (at breast height; DBH), wood density and tree height were used to estimate the above-ground biomass of all the species, which showed remarkably higher biomass for Avicennia officinalis. Possible adaptation of these species under extreme environmental conditions in addition to variations in vessel wall thickness caused by differential carbon fixation and storage in the form of biomass could explain the variability in elemental properties of mangrove stem wood. Heritiera littoralis and Kandelia candel with relatively higher lignin to cellulose content showed greater potentials to sustain biotic and abiotic stresses and indicated higher carbon sequestration as recalcitrant biomass. The lowest carbon density and highest ratio of cellulose/lignin in the Sonneratia apetala and Sonneratia caseolaris species indicated faster plant growth compared to the other studied species. FTIR analysis evidenced that the increase in the 1728–1733 cm −1 band height assigned to cellulose and decrease in the 1517–1519 cm −1 band height assigned to lignin.

The genetic assembly of Avicennia marina (Forsk.) Vierh, Avicenniaceae within and between the three natural mangrove forests of Kerala coast belonging to the districts of Kochi, Kozhikode and Kannur was investigated using Inter Simple Sequence Repeat (ISSR) markers to provide coherent scientific conservation practices. The ten selective ISSR primer combinations of 60 genotypes of Avicennia marina ensured a total of 171 bands of which 84.5% were polymorphic. Gene diversity index H varied from 0.142 Kochi to 0.195 Kozhikode. The mean gene diversity HS was 0.169 and the total gene diversity HT was 0.262 which showed a moderate level of genetic diversity in the studied population. The mangrove Avicennia marina populations showed large genetic difference GST = 0.3849, indicating that 38% of the total genetic diversity was among the populations and the rest 62% resides within the population. The gene flow estimates Nm = 0.79 shown that natural mangroves of Kerala are in the course of differentiation due to genetic drift. We investigated the genetic distinctiveness of taxonomically confusing species, Avicennia marina and Avicennia officinalis, and resulted in clear demarcation between the two. There is a significant correlation between dendrogram and PCoA designated that extensive distant spreading of seeds between populations of Avicennia marina is comparatively low. The genetic study contributed relatively high diversity and strong differentiation across the three eco-geographic locations. The best remedy to preserve coastal mangrove species like Avicennia marina is to plant the identical species in its respective habitat. Launch, on-site protection zones to safeguard the species and to decrease the impact of human activities would allow its habitats to increase in size through natural regeneration.

The species-specific potentiality of mangroves in terms of ecosystem services is not well understood. Therefore, this study addressed the carbon sequestration and litterfall production potentiality of six major species in Sundarbans, Bangladesh, by evaluating three consecutive years of inventory data, including the stand variables and weather events impacts on them. The total mean aboveground, belowground biomass, biomass accumulation, and carbon accumulation rate were 243.4 Mg ha−1, 132.2 Mg ha−1, and 14.3 Mg ha−1 yr−1, 7.2 Mg ha−1 yr−1, respectively. Carbon stocks and sequestration rates are significantly influenced by stand variables such as diameter, density, and species composition. Large-sized trees and stands with lower density sequester more carbon than small-sized trees, and higher density stands. Among species, Avicennia officinalis contributed higher carbon to carbon stocks and also significantly different from other species for sequestering carbon, whereas Aglaia cucullata was the lowest. Mean annual litterfall was 10.01 Mg ha−1 yr−1, with the maximum litterfall for Hereteira fomes (19.2 Mg ha−1 yr−1) during the late summer or wet season (e.g., April to August). Litterfall showed a significant positive (p

The release of nutrients and anti-nutrients from mangrove leaf litter plays an important role in the biogeochemical cycling in aquatic environments and directly or indirectly affects water quality and food availability to shrimp. In this study, we assessed nutrient and anti-nutrient loss during decomposition of leaf litter at a concentration of 1 g/L for four mangrove species (Avicennia officinalis, Heritiera fomes, Sonneratia apetala, Sonneratia caseolaris) to monitor water quality and to estimate how leaf litter influences shrimp post larvae (PL) growth and survival. There were significant differences (P < 0.05) between the studied species in terms of mass loss of the leaf litter during the investigation period. There were also significant differences (P < 0.05) between the studied species in terms of loss of nutrients and anti-nutrients in the shrimp PL rearing tank during the four-week experimental period. Decomposing mangrove leaves stimulated availability of natural food for shrimp PLs. There was a strong positive correlation between mass loss and PL production. At the concentrations of leaf litter used, the anti-nutritional factors did not affect the PLs. PL survival with mangrove leaf litter was 75–82%, whereas all the PL died without any leaf litter. PL weight gain ranged from 0.83–3.33 mg/d where S. apetala leaf litter resulted in the highest PL growth rate, followed by A. officinalis, S. caseolaris and H. fomes, in that order (P < 0.05). Overall, mangrove leaf litter had a positive effect on shrimp performance in terms of growth and survival and this effect was highest for S. apetala leaf litter.

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 2017. 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 Heritiera 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 154.8 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 cucullata 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−1∙yr−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.

Salinity affects growth and development of plants, but mangroves exhibit exceptional salt tolerance. With direct exposure to salinity, mangrove roots possess specific adaptations to tolerate salt stress. Therefore, studying the early effects of salt on mangrove roots can help us better understand the tolerance mechanisms. Using two-month-old greenhouse-grown seedlings of the mangrove tree Avicennia officinalis subjected to NaCl treatment, we profiled gene expression changes in the roots by RNA-sequencing. Of the 6547 genes that were differentially regulated in response to salt treatment, 1404 and 5213 genes were significantly up- and down-regulated, respectively. By comparative genomics, 93 key salt tolerance-related genes were identified of which 47 were up-regulated. Upon placing all the differentially expressed genes (DEG) in known signaling pathways, it was evident that most of the DEGs involved in ethylene and auxin signaling were up-regulated while those involved in ABA signaling were down-regulated. These results imply that ABA-independent signaling pathways also play a major role in salt tolerance of A. officinalis. Further, ethylene response factors (ERFs) were abundantly expressed upon salt treatment and the Arabidopsis mutant aterf115, a homolog of AoERF114 is characterized. Overall, our results would help in understanding the possible molecular mechanism underlying salt tolerance in plants.

Mangrove pneumatophores (respiratory roots) form a unique habitat about which very little ecological information is available. In this study, epiphytic diatoms on the pneumatophore surface of Avicennia officinalis (L.) were investigated with a focus on their seasonal and vertical distribution. The results indicated that among the seasons, highest diatom abundance was observed in monsoon. Vertically, maximum abundance was observed on 0–5 cm of the pneumatophore during post-monsoon and pre-monsoon and then gradually decreased upwards, but during monsoon, 5–10 cm section hosted maximum abundance. There was a seasonal and vertical variation on the diatom abundance and their interactive effect. This is because diatoms probably avoid the basal section (0–5 cm) of the pneumatophore during monsoon due to excessive sediment burial caused by intense riverine flux and settlement of suspended material. Overall it was found that vertically, diatoms (>70%) are mainly concentrated on the lower 0–10 cm of the pneumatophore, probably because this section remains moist during emersion period (low tide). Among the diatoms, Melosira nummuloides and Bacillaria paradoxa exhibited dominance during the monsoon, whereas Thalassiosira spp., Navicula spp., and Nitzschia spp.were prevalent during post- and pre-monsoon. To the best of our knowledge, this is the first study describing the composition of epiphytic diatoms from the pneumatophore surface of A. officinalis. Keeping in mind that these aerial roots together greatly enhance the surface area for attachment of epiphytic diatoms, their cumulative primary production would probably surpass that of mangroves on a quantitative basis and needs future investigation.

Mangrove plants are endowed with various biologically active compounds which have potent antibacterial and antioxidant properties. In present study, a bioactivity-guided fractionation for antibacterial and antioxidant active metabolites from the twigs of Avicennia officinalis collected from Kuala Selangor Nature Park, Selangor, Malaysia gave 13 major fractions. The antibacterial activity of A. officinalis fractions using well-diffusion showed strong selectivity on the Gram-positive bacteria (Staphylococcus epidermidis, S. aureus and Bacillus subtilis) with minimum inhibition concentration (MIC) values of 0.156-5.00 mg/mL. However, no antibacterial activities were observed on the Gram-negative bacteria (Vibrio cholera, Enterobacter cloacae and Escherichia coli). The active antibacterial fractions were further isolated using several chromatographic techniques to give two naphthofuranquinones, namely, avicenol C (1) and stenocarpoquinone B (2). Meanwhile, the antioxidant activity of A. officinalis fractions were evaluated using DPPH radical scavenging assay exhibited low antioxidant activities. Molecular structure of the naphthofuranquinones was elucidated using 1 D and 2 D NMR spectroscopy.

Although studies on species-level classification and mapping using multisource data and machine learning approaches are plenty, the use of data with ideal placement of central wavelength and bandwidth at appropriate spatial resolution, for the classification of mangrove species is underreported. The species composition of a mangrove forest has been estimated utilising the red-edge spectral bands and chlorophyll absorption information from AVIRIS-NG and Sentinel-2 data. In this study, three dominant species, Heritiera fomes, Excoecaria agallocha and Avicennia officinalis, have been classified using the random forest (RF) model for a mangrove forest in Bhitarkanika Wildlife Sanctuary, India. Various combinations of reflectance/backscatter bands and vegetation indices derived from Sentinel-2, AVIRIS-NG, and Sentinel-1 were used for species-level discrimination and mapping. The RF model showed maximum accuracy using Sentinel-2, followed by the AVIRIS-NG, in discriminating three dominant species and two mixed compositions. This study indicates the potential of Sentinel-2 data for discriminating various mangrove species owing to the appropriate placement of central wavelength and bandwidth in Sentinel-2 at ≥10 m spatial resolution. The variable importance plots proved that species-level classification could be attempted using red edge and chlorophyll absorption information. This study has wider applicability in other mangrove forests around the world.

Mangrove forest are used widely for meeting fuelwood needs of local communities in the tropics. However, the implications of fuelwood extraction on mangrove ecology has received very little attention. In this study, we investigated the impact of such small-scale fuelwood harvesting practices on mangrove forest structure, composition, regeneration, and biomass and carbon stocks in a protected area on the east coast of India. We sampled vegetation plots in areas where harvesting was practised and where no harvesting was observed. We found that species composition differed across forest categories with Exoecaria aggalocha and Heriteria fomes dominating non-harvested forest types and Sonneratia apetela, Sonneratia caseolaris, Avicennia officinalis along with mangrove associates comprising a large proportion of harvested mangrove forests. Similarly, tree, sapling and seedling densities, basal area, and biomass and carbon stocks were also found to vary across forest categories, with overall lower values observed in harvested areas. Lastly, total aboveground (11%) and belowground (18%) biomass and carbon stocks were also lower in harvested forests than non-harvested forests. However, large DBH size-class trees were found in harvested areas implying selective cutting practices that conserved old-growth trees and contributed to larger mean carbon pools. As harvesting is selective, mainly for cooking fuel demands, integrated management plans are required to accommodate local cultural and economic needs of the communities in this region.

This study shows results on litterfall dynamics contributing to Net Primary Productivity (NPP) and phenology in three major mixed mangrove habitats in Cochin estuarine system, south-west coast of India. Eleven true mangrove species and three mangrove associates formed the plant biomass where Avicennia officinalis was abundant in Site 1, Excoecaria agallocha in Site 2 and Avicennia officinalis , Rhizophora mucronata were abundant in Site 3. Total tree density varied from 11760 stems ha −1 in Vypin Island (Site 2); 11440 stems ha −1 in Mangalavanam Bird sanctuary (Site 3) and 7680 stems ha −1 , Aroor (Site1). The average stands basal area of the three mangrove habitats were 75.54, 54.85 and 103.26 m 2 ha −1 . The mean annual litterfall production in Cochin mangroves was 16.57±6.58 t ha −1 y −1 in which leaves (53.90%) contributed more followed by flowers, propagules (28.66%) and twigs (17.44%). The spatial variability in litterfall recorded highest in lower latitudinal mangrove habitat, Site.1 followed by Site 2 and Site 3 (2413.36 ± 873.72, 1295.65 ± 401.09, 1263.28±255.28 g DW m −2 y −1 ). Site differences in litter production were statistically significant (one-way ANOVA p 0.001 for total litterfall and p 0.05 for litter components) between the three mangrove habitats. Litter components and total litterfall showed significant seasonality ( p 0.001 ). Highest litterfall was recorded in pre-monsoon period followed by post-monsoon and least in monsoon period. The temporal trend of litterfall was explained through rainfall and mean atmospheric temperature and a negative correlation was there to rainfall during the period. The mean carbon content in the litterfall was estimated as 42.96% of the dry weight and the primary productivity through litterfall in the study area was estimated to be 7.12±2.81 t C ha −1 y −1 . This will act as the major source of carbon input to the mangrove ecosystem and surrounding coastal ecosystems and in turn reflected in NPP.

There are few studies that dealt with species preference in seedling predation by sesarmid crabs in mangrove forests. We investigated predation preference of the sesarmid crab Neosarmatium malabaricum to the seedlings of Aegiceras corniculatum, Avicennia officinalis, Excoecaria agallocha and Rhizophora mucronata in Kunhimangalam mangrove forest in Kerala. Enclosure-exclosure experiments showed that the crab preferred seedlings of E. agallocha the most and that of R. mucronata the least. Reason for this preference was the cumulative effect of morphological and chemical factors of these seedlings. Morphological factors negatively and chemical factors positively influenced the predation preference. Species preference in seedling predation could be inversely proportional to relative abundance and density of saplings. Saplings of the most preferred A. corniculatum and E. agallocha registered low density, and the least preferred R. mucronata and A. officinalis recorded high density in Kunhimangalam mangrove forest. Species preference exhibited by N. malabaricum in seedling predation has been reflected in sapling density and composition. So, this preference can possibly influence the future forest composition.

Absorption, accumulation and translocation of 12 trace elements in nine dominant mangrove plants in the Indian Sundarban Wetland revealed both organ-specific and site-specific characteristics. An overall enrichment of elements was recorded in rhizosediment, exceeding the prescribed effects range-low (ER-L) of consensus based sediment quality guidelines (SQGs) for Cu and Pb. Avicennia officinalis, A. alba, Ceriops decandra and Excoecaria agallocha exhibited unique potential for accumulating Al, Cd, Co, Cr, Cu, Ni, Mn and Zn and could be considered efficient accumulators. Maximum element accumulation in trunk bark (As 6.16, Cr 49.9, Co 2.67, Cu 91.00 and Zn 85.5 mg kg−1) and root/pneumatophore (Al 1000 and Fe 2430 mg kg−1) was recorded. Maximum bioconcentration factor (6.23) in A. officinalis and translocation factor (17.5 for Mn) in C. decandra distinguished their phytoremediation capacity. These halophytes could be used for trace element phytoremediation in stressed sites of Sundarban.

The objective of this present attempt was to investigate the relationship between leaf quality and level of herbivory at study site during August 2010–July 2011. Total amino acids with a maximum of 9.47 mg g −1 during February 2011 in Rhizophora mucronata and a minimum of 4.671 mg g −1 in May 2011 in Avicennia officinalis were noticed. Tannin was maximum (6.844 mg g −1 ) during April 2011 and minimum (0.667 mg g −1 ) in July 2011 in A. officinalis . Total nitrogen showed a maximum of 9.851 mg g −1 during February 2011 in R. mucronata and a minimum of 2.158 mg g −1 in February 2011 in A. officinalis . Total sugars registered a maximum of 4.075 mg g −1 during March 2011 in A. officinalis and a minimum of 0.063 mg g −1 in March 2011 in R. mucronata . Total phosphorus recorded the maximum (4.321 mg g −1 ) during November 2010 in R. mucronata and minimum (0.258 mg g −1 ) during May 2011 in A. officinalis . Potassium content was maximum (3.710 mg g −1 ) during October 2010 in R. mucronata and minimum (0.039 mg g −1 ) in July 2011 in A. officinalis . These data suggest that artificially developed mangrove ecosystems may be an adaptive mechanism related to nutrient conservation, and that it is associated with mangrove survival in phosphorus-deficient soil rather than an adaptation to herbivory.

The Sundarbans, the largest mangrove forest in the world and a UNESCO world heritage site has been facing increasing pressure of habitat destruction. Yet, no study has been conducted to test how human disturbances are affecting plant-pollinator interactions in this unique ecosystem. Hence, we aimed to provide the first insight into the impact of habitat loss and human disturbances on the pollinator communities in the Sundarbans. We selected 12 sites in the North-Western region of the Sundarbans, along a gradient of decreasing habitat loss and human activities from forest fragments near human settlements to continuous pristine forest, where we studied insect pollinators of two mangrove plant species, Acanthus ilicifolius and Avicennia officinalis. Our results show that different pollinator groups responded to the disturbance gradient differently. For example, the abundance of Apis dorsata, one of the three local species of honey bees, increased gradually from the village area towards the deep pristine forest. On the other hand, A. cerana and A. florea were found in the village sites and completely absent in the deep forest. Although pollinator community composition changed along the disturbance gradient, their efficacy in pollination did not seem to be significantly affected. However, lower plant diversity and low understory plant cover in the forest patches nearby the village indicated that human disturbances not only affected pollinator community composition but also played a major negative role in the regeneration of the forest. Our study provides first insights into plant-pollinator interactions in the Sundarbans and demonstrates that more research is needed to imply conservation strategies for this unique habitat.

The forest structure and its relation to environmental parameters of Sundarbans, largest mangrove habitat in India, are presented. Quadrat method was used to analyze the vegetation-environment interaction and structural maturity of mangroves. Floristic studies revealed twenty-seven mangrove species including the critically endangered Sonneratia griffithii and endangered Heritiera fomes. Based on Importance Value Index, Avicennia marina, Excoecaria agallocha, Avicennia officinalis and Avicennia alba were designated as the most important species. Higher diversity indices were observed (Shannon index, ranged from 4.2-1.8; Pielou’s index, 0.96-0.91) revealing greater species diversity and even dispersion of mangroves in Sundarbans. Stem density varied from 133 to 19333 ha−1 and individual basal area 0.4 to 13.4m2ha−1. A very low Maturity Index Value was recorded indicating a low degree of structural maturity. Most of the vegetation parameters (density, species diversity index, β diversity) and few of the edaphic parameters (pH, grain size, total carbon) were found to be in better condition; however, salinity showed significant negative correlations with vegetation characteristics. The study revealed a mixed species composition with intermediate structural development indicating a growing forest in Sundarbans. The data evolved in the study would be fundamental in site-specific management and conservation efforts of mangroves in this world heritage site.

Mangrove forest ecosystems have a very important role for humans and the environment, so to prevent further damage needs to be done identification of tree species composition and structure of mangrove forest stands. For the purpose of this research is to know the composition of tree species from the level of seedling to the tree and to know the structure of its stand. Data collection methods used are Inventory of mangrove species using Indonesian mangrove determination keychain and data analysis by calculating important value index, Diversity index, relative frequency and horizontal structure analysis. The results showed that the largest tree density structure was Rhizophora mucronata of 225 trees / hectare, Avicennia marinna of 145 trees / hectare, Sonneratia alba of 65 trees / hectare and Avicennia officinalis of 65 trees / hectare and had only one crown layer namely strata A which is dominated by Rhizophora mucronata tree which has an average free height of 9 m branch with total height 12 m and diameter 29 cm. For this reason, planting efforts need to be increased to increase the number and composition for coastal protection.

The Ganges Delta and Sundarbans comprise the largest continuous mangrove area in the world. These mangroves are subjected to high riverine and tidal dynamics, and the coastline irregularity is characterized by many north-to-south oriented rivers that may hamper dispersal of mangrove propagules. Whereas connectivity levels and resulting population genetic structure often can be explained by ocean currents, other factors may control estuarine-scale mangrove genetic patterns and limit gene flow even between sites in close geographic proximity. We investigated whether the complex estuarine coastline in the Ganges Delta and Sundarbans shaped the genetic structure of Avicennia officinalis populations across regions and rivers at various distances (ca. 1 to 265 km). Using nine microsatellite loci, 433 individuals from 14 populations revealed predominant outcrossing and a high level of genetic variation when compared to other Avicennia species. A moderate but significant level of differentiation was detected among populations (F ST = 0.09), and a principal coordinate analysis clearly separated populations of the Chittagong coastline from the Sundarbans. An individual-based Bayesian analysis also indicated those two gene pools. Genetic distances across the whole region could best be explained by cumulative river width and geographical distance separating the populations. Within the Sundarban region, the low genetic differentiation of A. officinalis populations indicated a continuous distribution model with a smooth isolation-by-distance that gradually increased across large rivers shaping the genetic structure of A. officinalis in the Ganges Delta. These findings indicated that in addition to geographical distance, rivers might act as physical barriers, affect gene flow and shape genetic connectivity. This and detailed population genetic information should be incorporated into the ongoing afforestation or restoration strategies in and outside of the Sundarbans mangrove forest.

Mangroves are the plants adapted to strident environment with unvarying inundation of the soil and extremely diverse salinities, habitual in river banks, sand flats and coastlines of the tropics and subtropics of the world. Mangrove vegetation in six geographical regions of Kollam on the Southwest coast of India was selected to study the phytosociological characteristics and diversity indices. We analysed the pattern of mangrove species diversity, density and basal area and similarity parameters. Totally, 12 species of mangroves belonging to 8 genera and 6 families were identified; Rhizophoraceae and Avicenniaceae were the most dominant group represented. Highest density was recorded for Avicennia officinalis (3760stems/ha), followed by Avicennia marina (3721stems/ha). Avicennia officinalis is the most common mangrove counted with the highest Important value index (IVI) and Relative IVI; 64.19 and 21.40 respectively. Shannon- Weiner Index of diversity ranged from 2.002 to 3.11; species richness from 0.429 to 1.033 and the similarity in floral composition varied from 0.33 to 0.66. The sites selected were distinct from one another and the species diversity varied from one place to another; influenced by the climatic, biotic, anthropogenic stresses.

The Sunderban Biosphere Reserve of southern West Bengal, India offers an ideal locale where Hyperspectral Remote Sensing may be applied for mapping diverse range of mangrove plantations that are unique to this pristine ecological system. This delta is characterized by both ‘pure’ and ‘mixed’ mangrove forest patches where photons interact with multiple species within the instantaneous field of view of the hyperspectral sensor, and multiple scattering between the vegetation canopies becomes significantly nonlinear. This paper attempts to apply the principle of multiple scattering of light in naturally occurring conditions and see how best they describe the resultant mixed spectra for certain endmember distributions. It is observed that natural forests, mixed mangrove forest in this case, are better suited for non-linear scattering models as compared to linear models. The non-linear model has successfully identified areas of interaction of mangrove mixtures such as ceriops-excoecaria-phoenix, excoecaria- avicennia alba avicennia officinalis etc. in the study area.

The Indian Sundarbans region at the apex of the Bay of Bengal in Eastern India is impacted by industrial and urban development, including the discharge of large volumes of wastewater. We analyzed the concentrations of zinc (Zn), copper (Cu) and lead (Pb) in the root, stem and leaves of four dominant mangrove species, Avicennia officinalis, Avicennia marina, Avicennia alba and Excoecaria agallocha in samples collected from 12 different monitoring stations in the Indian Sundarbans. At all of the stations, the magnitude of accumulation of the metals in the vegetative parts of the mangroves was in the order, root > stem > leaf. The maximum concentrations of zinc in the roots (116.1 ± 4.2 μg/g dry weight) and the stems (100.4 ± 6.2 μg/g dry weight) was observed in A. officinalis collected at the Kakdwip site, whereas in leaf tissues, the maximum mean zinc concentration (66.8 ± 3.5 μg/g dry weight) was observed in A. marina collected at the Chemaguri site. The concentrations of copper were lower, with the maximum mean concentration (51.1 ± 3.0 μg/g dry weight) in the roots of A. officinalis at Kakdwip. In all vegetative parts, the concentrations of lead were lowest relative to the other metals, with the maximum mean concentration (30.4 ± 2.0 μg/g dry weight) observed in the roots of A. officinalis at Kakdwip. The concentrations of metals were generally lower in the vegetative parts of E. agallocha relative to the other mangrove species. Simultaneous analysis of dissolved metals in the surface waters at the monitoring stations revealed that zinc was present in high concentration, followed by copper and lead. Among the 12 selected stations, the highest concentrations of dissolved zinc, copper and lead were observed at Kakdwip at concentrations of 668.5 ± 5.4, 176.3 ± 4.6 and 48.4 ± 3.1 μg/L, respectively. This site is located in the western part of the Indian Sundarbans. The site at Bagmara in the eastern part of the study area had the lowest concentrations of dissolved heavy metals, as well as the lowest concentrations of the metals in sediments. High metal concentrations in sediments observed at the Frasergunj site (117.3 ± 4.3 μg/g dry weight for zinc, 37.7 ± 2.4 μg/g dry weight for copper and 10.8 ± 1.0 μg/g dry weight for lead) may be due to the presence of a fish landing station at this site. There were significant correlations between the levels of the metals in ambient media (i.e. water, sediments) and the concentrations of the metals in the vegetative parts of the mangroves; indicating that the levels of metals in mangroves reflect environmental exposures. The results indicate that mangrove species can accumulate these metals from the marine environment to ppm concentrations. Bioaccumulation factors for A. officinalis vegetation relative to sediment appeared to be >1 for lead, which is discussed in the context of using this species for bioremediation; a new dimension in the spectrum of ecosystem services offered by the mangroves.

Mangroves are a group of halophytic, evergreen, woody plants and shrubs that occupy the intertidal zone. The Jaffna peninsula has some of the major mangrove sites in Sri Lanka with large extents of undisturbed mangroves. As a result of the three-decade long armed conflict that prevailed in the entire northern part of the Island, mangrove diversity and distribution has never been evaluated since 1969. The objective of the present study was to identify the mangrove species and their distribution in the Jaffna peninsula. Five locations were selected based on the distribution of mangrove vegetation. These are Mandaitivu (East and West), Sirudivu, Kuruchidivu, Kurikadduwan, and Kaluthaipiddi. Random quadrat method was used to assess the abundance of mangrove species in the area. A total of 21 species of true mangrove plants have been recorded in Sri Lanka and the present study identified seven (07) species in the Jaffna peninsula. These are Bruguiera cylindrica, Avicennia marina, Avicennia officinalis, Rhizophora mucronata, Excoecaria agallocha, Lumnitzera racemosa, and Ceriops tagal. A mangrove associate, Acanthus ilicifolius was also recorded. Of these, Bruguiera cylindrica is a species with restricted distribution. In the present study it was recorded only from Sirudivu (density 169/km2). Avicennia marina is the dominant species on the Islands and Southern coastal line. The island of Mandaitivu had a high density of this species (293/km2 on East and 1208/km2 on West Mandaitivu). Kuruchidivu also had a higher density (2571/km2) of this species compared to other island areas. Avicennia officinalis was restricted to Sirudivu and Kuruchidivu (density 246/km2 and 100/km2 respectively). Mangroves are one of the most diverse ecosystems and they provide suitable habitats for a large number of migratory bird species and other aquatic species such as fishes, shrimps, crabs, etc. which are important to marine fisheries in Sri Lanka. They are one of the most productive ecosystems on the earth. The mangroves also protect the coasts from the impacts of storms. The study area has large extents of relatively undisturbed mangroves, found mainly on the Eastern side of the Jaffna peninsula along with the lagoon line and the Southern part of the peninsula along the coastal line. Hence the present area has a considerable conservation value. Keywords: True mangroves, Mangrove associates, Distribution, Islands, Jaffna Peninsula

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

Mangrove forests are a valuable economic resource as important breeding grounds and nursery sites for various animal species, stabilizing coastal lands and offering protection against storms, tsunamis, and sea level rise. Mangrove forest growing along the coastline of Serewe Gulf. The Serewe Gulf has great potential in tourism and sea cultivation sector. The research was conducted in the Serewe Gulf of Lombok Island, West Nusa Tenggara for 2 months (November up to December 2016). The objective of this research is to determine the diversity of mangrove in the Serewe Gulf, Lombok Island, West Nusa Tenggara using belt transect method. The identification result shows that there are 9 families with 9 types such as Rhizophoraceae (Rhizophora mucronata), Avicenniaceae (Avicennia officinalis), Sonneratiaceae (Sonneratia alba), Casuarinaceae (Casuarina equisetifolia), Bignoniaceae (Dilochnadrone sthaceae), Malvaceae (Hibiscus tiliaceus), Lythraceae (Pemphis adicula), Aizoaceae (Sesivium portulacastrum), and Euphorbiaceae (Ricinus communis). The diversity of mangrove types in the research area is in medium rate with H’ index of 1.668.

The aim of the study was to determine growth performance of planted mangroves at three beats of Mirersarai forest range in the Chittagong coastal afforestation division, Bangladesh. This 22–29-year-old mangrove plantation showed satisfactory growth and regeneration with variations among different study sites. The study revealed that individual species density and overall density (stem/ha) in the study sites varied significantly (p ≤ 0.05) where density of Sonneratia apetala was maximum among five species followed by Excoecaria agallocha, Avicennia officinalis, Ceriops decandra and Bruguiera sexangula. Sonneratia apetala attained the highest mean diameter at breast height (DBH) (cm) and height (m) among all the plantation species. It was found dominant at the middle section plantations of three beats, whereas Bruguiera sexangula and Ceriops decandra were found absent at seaside plantation sites. Overall tree density was found to be highest at the middle part (1880 stem/ha) followed by inland (1610 stem/ha)...