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One new 8,4’-oxyneolignan (1) and one new 7,8-dihydrobenzofuranone (2), together with twenty-one known compounds (3‒23) were isolated from the methanol extract of Rhizophora apiculata leaves. The structures of new compounds, as well as their absolute configuration, were determined by a combination of spectroscopic methods and quantum chemical calculations of NMR and ECD data. All isolated compounds were evaluated for their cytotoxicity, and only 2,6-dimethoxy-1,4-benzoquinone (8) exhibited inhibitory effects against SK-LU-1, HepG2, and MCF7 cells with IC50 values in the range of 8.33–14.82 μM.

In many tropical nations, mangrove forests are essential ecosystems for climate change mitigation and adaptation in coastal regions as they provide important forest resources as well as a suite of other benefits to communities including carbon sequestration. Empirical growth and yield modelling methods derived from terrestrial forestry, which are often robust with respect to forestry forecasting and management, have not often been assessed in mangrove forests yet they are important for underpinning sustainable forest management. We surveyed 89 Rhizophora apiculata mangrove plantations with age ranges from 4 to 26 year old in Vietnam, destructively harvesting 25 trees for biomass measurements and 70 for stem analyses, to assess increments in biomass and standing timber. Systems of equations were developed to model site index, mean diameter, dominant height, stocking, biomass and timber volume. We found that conventional forest growth modelling methods fitted the observed data well. Similar to terrestrial forests, stand height is a good indicator of site productivity. Mean errors for stand volume and biomass estimated from yield tables were both less than 5.3%. The root mean square error (RMSE) of the biomass model was 12 and RMSE of the volume model was 10.8, suggesting that these methods are applicable to evenly aged monoculture mangrove plantations in Vietnam. Our research also indicated high variation in mean annual increment of biomass (MAI) in the surveyed plantations due to a wide range of age and site conditions. Some R. apiculata plantations in Vietnam can reach a peak aboveground biomass MAI of 22.7 Mg ha−1 year−1, which is among the highest of published values from plantations of the same species worldwide. Further studies addressing the application of terrestrial forest growth methods to mangrove systems are suggested in order to develop reliable and useful tools for sustainable management of this important ecosystem.

Hazards in coastal areas such as tsunamis, abrasion and sea level rise may cause ecosystem degradation, building damage, and human death. One strategy to mitigate the possible impacts of such risks is to design mangrove landscaping. This design uses the wood properties of modulus of elasticity (MoE), modulus of rupture (MoR), and other properties. MoE and MoR reflect the strength of wood to reduce the impact of hydrodynamic forces in coastal areas. The destructive method was used to analyze the MoE and MoR of mangrove trees from two stations (West Segara Anakan and East Segara Anakan), which have 20 sampling plots (size 10 m × 10 m) as replicates for each station. The results showed that mangrove species have MoE score ranging from 50.000 kg cm−3 to 171.802 kg cm−3 and MoR score ranging from 400 kg cm−3 to 1503.44 kg cm−3. Accordingly, mangrove landscaping design in West and East Segara Anakan based on MoE and MoR properties were proposed with the following classes: class 1 Rhizophora apiculata and Bruguiera parviflora, class 2 B. gymnorrhiza, B. sexangula, R. stylosa and R. mucronata, class 3 Avicennia alba, Sonneratia alba, Xylocarpus granatum and X. moluccensis and class 4 Nypa frutican and Casuarina equisetifolia.

This study aimed to determine the role of mangroves as a biofilter of heavy metals. The concentrations of heavy metals, namely copper, mercury, cadmium, zinc, and lead, in the mangroves Rhizophora apiculata, Ceriops tagal, Bruguiera gymnorrhiza, Lumnitzera racemosa, Xylocarpus granatum, Sonneratia alba, and Bruguiera parviflora at RAWN Park were determined using a Flame atomic absorption spectrophotometer. High concentrations of Cu (83.85μgg-1) and Hg (0.52μgg-1) were found in the tissues of L. racemosa, while high concentrations of Cd (10.81μgg-1), Zn (70.41μgg-1), and Pb (1.36μgg-1) were found in the tissues of B. gymnorrhiza, B. parviflora and C. tagal, respectively. The translocation and bioaccumulation factors of heavy metals by mangroves showed a variety of trends, which indicated the different partitioning and uptake capability of heavy metals in the tissues of various mangrove species. Thus, maintaining high diversity of mangroves is crucial to ensure the health and productivity of coastal zones.

The ability of mangrove ecosystem to accumulate carbon from air, water and soil as sinker carbon is very important to reduce carbon emission in coastal ecosystem. Carbon sink represent role of mangrove ecosystem to sequestrate carbon emission is developed by a system of mangrove zone and demonstrative activities system. These paper purposes to develop system of carbon conservation in mangrove ecosystem to apply REDD program and demonstrative activities. The research methods used Komiyama equation tCer analysis and demonstrative activities formulation. The research results showed that the carbon percentage of mangrove species between 35.97%–53.98% with Bruguiera gymnorrhiza (52.54%) and Rhizophora apiculata (52.38%) as the biggest carbon sinker of mangrove species. The carbon of mangrove ecosystem were 79.2 tonC/ha −242.2 tonC/ha, with the economic value between 396.2 US$/ha (price 5 U$/tonC) −4360.4 US$/ha, (price 18 US$). The best choice of demonstrative activities in REDD framework to reduce the degradation of mangrove ecosystem was the fish pond. And the best carbon sequestration of mangrove species were Bruguiera praviflora, Rhizophora mucronata, Bruguiera sexangula, Rhizophora apiculata and Bruguiera gymnorrhiza (first mangrove zone).

Wetlands are important ecosystems that provide many critical services for ecology and human communities. In the Mekong Delta (MD), Vietnam, the combined effects of climate change and sea level rise (SLR) threaten coastal mangrove forest wetlands, while inland Melaleuca forest wetlands are affected by regional changes in climate. Hence, it is essential to understand the impacts of climate change and SLR on these wetlands, particularly on the dominant species, which are integral to the structure and function of each wetland type. However, future climate suitability for wetland species is not yet well documented and well researched for the region. Therefore, this study examines the potential impacts of climate change and SLR on the three dominant species of these wetland types, Avicennia alba (A. alba) and Rhizophora apiculata (R. apiculata) in coastal mangrove forest wetlands and Melaleuca cajuputi (M. cajuputi) in inland Melaleuca forest wetlands, utilizing an ensemble modelling approach. The species occurrence points, bioclimatic and eco-physiological variables were used to model habitat suitability for the three species under current and future climate scenarios, RCP4.5 and 8.5 for 2050 and 2070. The projected reduction in habitat suitability of A. alba, R. apiculata, and M. cajuputi by mean values of 27.9%, 28.7% and 30.0%, respectively by the year 2070 indicates the vulnerability of the wetland species to climate change impacts. Increases in temperature, and in seasonal variation in precipitation and temperature, and SLR were key driving factors responsible for the losses of suitable habitat. Our findings provide useful information and data sources for development of plans and strategies to protect and conserve the wetlands from future climate change impacts.

Mangrove leaves form a large pool of carbon, nitrogen and energy that is a major driver of element cycles and detrital food webs inside mangrove forests as well as in adjacent coastal waters. However, there are large gaps in knowledge on the transformation pathways and ultimate fate of leaf nitrogen. Therefore, the main objective of this study was to determine the amount and composition of nitrogenous organic matter and possible species-specific differences during the decomposition of mangrove leaf litter. For that purpose a three month decomposition experiment with litterbags was conducted using leaves of Aegiceras corniculatum, Avicennia alba, Ceriops decandra, Rhizophora apiculata, and Sonneratia caseolaris in the mangrove forest of the Segara Anakan Lagoon, Java, Indonesia. Detrital leaves were analyzed for bulk carbon and total nitrogen (N), stable carbon and nitrogen isotope composition (δ13C, δ15N), total hydrolyzable amino acids (THAA) and total hydrolyzable hexosamines (THHA). Decomposition rates (k d−1) were highest and tM50 values (when 50% of the original mass had been degraded) lowest in S. caseolaris (k = 0.0382 d−1; tM50 = 18 days), followed by A. alba, C. decandra, A. corniculatum, and R. apiculata (k = 0.0098 d−1; tM50 = 71 days). The biochemical composition of detrital leaves differed significantly among species and over time. S. caseolaris and A. alba had higher concentrations of N, THAA and THHA and a lower C/N ratio than the other three species. For most of the species concentrations of N, THAA and THHA increased during decomposition. The hexosamine galactosamine, indicative of bacterial cell walls, was first found in leaves after 5–7 days of decomposition and increased afterwards. Our findings suggest an increasing, but species-specific varying, portion of labile nitrogenous OM and total N in decomposing leaves over time that is partly related to the activity of leaf-colonizing bacteria. Despite a higher relative nitrogen content in the remaining litter of the fast decomposing S. caseolaris and A. alba as compared to the other three species, the total loss of nitrogen was even higher because of the much higher mass loss after three months of decomposition. It is inferred that the amount of labile nitrogenous organic matter plays a major role in determining the rate of decomposition of leaf litter in mangroves.

The objective of this study is to investigate the effects of river vegetation and timber piling on the attenuation of ship-generated waves that cause erosion at river bank. A numerical model based on two-dimensional Boussinesq-type equations was developed to predict the ship wave prorogation through river vegetation and timber piling. The model was validated with the field data and found that the model can reproduce well the field data when the disturbances from tides and winds were minimal. The numerical model was then used to simulate ship wave propagation through a belt of river vegetation consist of Rhizophora apiculata, a dominant type of mangrove s planted in the Ca Mau River in the south Vietnam, and a timber piling. A 200 m long timber piling, parallel to the river bank, at 10 m from the bank reduced 51% and 89% of run-up height and wave force at the bank, respectively. If the timber piling combined with 20 m width of the vegetation the run-up height and wave force were reduced further 61% and 95%, respectively.

Phytoaccumulative capacity for heavy metals (Zn, Ni, Fe, Mn and Cr) of mangrove species (Rhizophora apiculata, Avicennia sp. Sonneratia alba) was evaluated on sediments collected along the riparian zone of mining-impacted river. Ni, Fe, Mn and Cr exceeded the probable effect level suggesting their potential adverse effects to aquatic organisms and ecosystem. Metal concentration in the sediments was in decreasing order of Fe>Cr>Ni>Mn>Zn. The potential for metal accumulation which was assessed using bioconcentration factor (BCF) and translocation factor was found to vary depending on metals, mangrove species and plant tissues. The tested metals highly accumulated in the roots except for Mn with higher uptake in the leaves. Highest BCF was recorded on Zn (0.7) in Avicennia sp. while metals with high mean level in sediments (4,244.1mg/kg Ni, 137,049.4mg/kg Fe and 13,985.9mg/kg dry weight Cr) registered lower BCF. Variations in metal uptake of the same species could be due to differences in metal bioavailability and sediment characteristics. Limited translocation of Cr in all species, Ni on S. alba, Fe in R. apiculata and Avicennia sp. suggests that they can potentially be used for remediation of Ni-Cr-Fe laden sediments particularly for phytostabilization. Enhancement of metal uptake by mangroves through increasing metal bioavailability should be explored in future studies.

Mangrove rehabilitation efforts regularly intend to re-establish the former canopy cover quickly by establishing even-aged monocultures. However, there are concerns that these stands are less resilient to disturbances than structurally diverse forests and cannot provide ecosystem services as effectively. The objective of this study was to identify silvicultural systems for the transformation of even-aged Rhizophora apiculata stands to more irregular and species-diverse stands. The individual-based forest model KiWi was used to simulate the dynamics of a 1-ha sized Rhizophora apiculata stand under (1) passive management without intervention, (2) stand clearcutting, (3) group clearcutting, (4) expanding-gap shelterwood, and (5) crown thinning. As observed in the field, seedlings of the less shade-tolerant tree species Avicennia marina regenerated naturally under the canopy of R. apiculata. The transformation process was considered complete at the onset of the steady state characterized by a multi-layered forest structure as well as a stable basal area and stem size distribution. Without intervention, stands entered a steady state, on average, after 226 years under poor site conditions, or 179 years under good conditions. Silvicultural systems that required multiple entries, specifically expanding-gap shelterwood and crown thinning, halved this time by creating multi-layered stand structures while retaining a partial canopy cover. Moreover, continuous crown thinnings were necessary to maintain a species-diverse upper canopy. In contrast, small group clearcuts developed into two-layered stands and were ineffective. The removal of the upperstory through a stand clearcut or a large group clearcut reversed the initial planting arrangement but could develop into irregular stand structure only if propagules were supplied uninterruptedly. Intense forest operations were necessary to accelerate the transformation of even-aged mangrove stands. Forest managers should consider the potential future costs of transformation when planting even-aged stands instead of assisting the natural regeneration of former mangrove sites. Silvicultural field trials are proposed for the development of detailed guidelines.

Three species of mangroves and six species of salt marshes were collected from various locations along the Tuticorin coast for the estimation of metals like Cu, Cd, Pb, and Zn. The bioaccumulation of metals in mangroves is in the order of Cu Pb Zn Cd, and the season-wise accumulation was higher in monsoon followed by summer, post-monsoon, and pre-monsoon seasons. The accumulation of metals in mangroves showed higher in Rhizophoraapiculata followed by Avicenniamarina, and Rhizophoramucronata. The concentration of metals in salt marshes is in the order of Pb Zn Cu Cd, and the species-wise accumulation showed in the order of Suaeda maritime Ipomoea sp. Suaeda sp. Spinifix littoreous Sesuvium portacastrum Ipomoea pes-capras. BAF in salt marhes and mangroves is as Cd Pb Cu Zn and Cd Cu Pb Zn, respectively.

Rhizophora apiculata is a less studied tannin-rich plant of the mangrove ecosystem with potent biomedical applications. Tannins have been known to reduce silver ions into silver nanoparticles which in particular are known to possess cytotoxic effects against a variety of cancer cells. The aqueous leaf extract was prepared and quantitatively analyzed for its phytochemical content. According to the quantitative phytochemical analysis, the extract was rich in tannins and other reducing sugars. The reducing sugar-rich extract was further used for the synthesis of silver nanoparticles. Taking these facts into consideration, in this study, an eco-friendly approach was followed to biosynthesize silver nanoparticles using a tannin-rich Rhizophora apiculata aqueous leaf extract. The synthesized nanoparticles were partially characterized by our previous reports. This report further characterizes the particles by determining its average size, polydispersity index and zeta potential using dynamic light scattering. After characterization, the nanoparticles were tested for cytotoxic effects against human osteosarcoma MG-63 cells. The effects were analyzed by microscopic observation and MTT assay. The results indicate that the tannin-rich extract reduced the precursor silver nitrate into silver nanoparticles of favorable size for tumor infiltration. The nanoparticles possessed significant cytotoxic effects against MG-63 cells which could be possibly attributed to the antioxidant activity of silver nanoparticles. Further studies at the molecular level can indicate its potential in nanomedicine for the treatment of bone cancer at the clinical level.

Pollen analyses of surface and core sediments from the Ranong Biosphere Reserve, Ranong Province, Thailand, were carried out to determine spatial and quantitative compositional fidelities of the pollen record to achieve more accuracy in the reconstruction of past mangroves. The results reveal that many taphonomic biases from both biological and physical variables can lead to misinterpretation of the pollen records. Autochthonous pollen from true mangrove species were predominant in forest sediments, suggesting that mangrove sporomorphs are potential indicators of mangrove environments, while the frequent occurrence in low numbers of allochthonous and parautochthonous palynomorphs in mangrove sediments can reflect the regional plant communities. Close relationships between pollen from Bruguiera, Rhizophora apiculata, and Sonneratia alba and their vegetation were observed. The spatial reliability of Avicennia alba, Aegiceras corniculatum, Ceriops tagal, and Xylocarpus sp. pollen was low. The sediment cores show that the mangrove forest with its plant zonation was prograding towards the sea over time. The decline in R. apiculata pollen concentrations recovered in the upper part of all sediment cores reflects a decrease in the population of this plant taxon in the forest possibly caused by logging.

Strong winds and storm surges from Typhoon Haiyan caused damage of US$12-15billion and >10,000 human casualties in central Philippines in November 2013. To validate a proposed government US$22million mangrove replanting program, mangrove damage and short-term recovery were surveyed in seven natural and planted mangrove sites in Eastern Samar province at 2.5month and 4.5month post-Haiyan. The preliminary assessment showed that natural mangroves (except for those directly hit by the storm) were recovering by means of tree sprouts and surviving seedlings and saplings compared to the devastated plantation. Likewise, tree mortality was higher in the plantation and natural forests hit by the storm surge, compared to more undamaged and partially damaged trees in natural mangroves. Hence the main recommendations to government are (1) to protect recovering mangroves by not releasing rehabilitation funds (that will inadvertently pay for clearing of live trees and for removal of seedlings), (2) to only plant in totally damaged sites (e.g., plantations), and (3) to only plant naturally dominant species, e.g., Sonneratia alba and Avicennia marina (instead of the popular Rhizophora apiculata, R. mucronata and R. stylosa).

Phytoremediation studies were performed for the removal of chromium by young mangrove species Rhizophora apiculata. A pilot remediation system was constructed in a greenhouse consisting of aquaria with mangrove trees, which were flooded twice a day to simulate natural conditions of mangrove swamps. The effects of chromium loads, soil environment and fertilizer on the remediation process were studied in a three factorial experiment. From the obtained data, a mathematical model was derived capable of simulating the operation of a phytoremediation system in dependence on the control variables including number and size of the trees, soil type and chromium load. The model was applied to assess the performance of the system under different operation modes. The results obtained both by the experiments and simulation studies show that bioextraction of chromium using young mangrove trees is feasible. The inhibition of plant growth at high chromium concentrations causes a complex dynamic behavior of the system. Therefore, a careful choice of the control variables is necessary to ensure optimal performance of the system.

Mangroves are inundated through tidal action, which mobilizes a large quantity of suspended and dissolved particles, including both decomposed mangrove and terrigenous materials. Sediments brought in by tidal water and trapped by mangrove roots contribute to the productivity of coastal, tropical mangrove ecosystems. They play an important role in the nutrient cycling of these ecosystems. However, there is limited information on sediment properties, inclusive of nutrients levels in tidal-borne sediments affecting mangrove ecosystems. Selected properties of sediment, including cation exchange capacity (CEC), texture, organic matter (OM) content, organic carbon (OC) content, and nutrient content (C, N, S, P, K, Ca and Mg) were studied, in a seasonal pattern, in tidal-borne sediment from Sibuti estuary mangrove. Sediment showed a high proportion of sand (range: 60%–65%) with high mean values of CEC 17 cmol/kg, a sediment OM content of 15%, and OC content of 13%. The mean average content of C was 15%, and mean concentrations of N, S, P, K, Ca, Mg and Na were 12, 10, 2, 3, 34, 18 and 16 (mg/kg), respectively. Significant positive relationships were found among nutrient concentrations in sediment and nutrient concentrations in leaf, stipule, flower, propagule, stem, bark, and root of both Rhizophora apiculata (Blume) and Xylocarpus granatum (Koenig) trees and their saplings. Seedlings are indicative of the growth, health, and productivity of the mangrove ecosystem, and are largely dependent on the phenomenon of nutritive aspects of tidal-borne sediments. The results of this study provide baseline information on the roles of nutrient productivity of a less disturbed tropical mangrove forest, adjacent to the South China Sea.

Herbal tea is medicinally well-known for its biochemical composition and medicinal usages. The present study proved for the first time that tea would be extracted from mangroves, the plants other than commercial tea. Mangroves tea exhibitd good quality in the terms of theaflavin (TF), thearubigins (TR), total liquor colour (TLC) and highly polymerized substantce (HPS). Phytochemical screening of tea revealed the presence of phytochemical compounds such as protein, phenol and flavonoids etc. The antioxidant properties of Rhizophora mucronata, Rhizophora apiculata, and Rhizophora annamalayana showed dose dependent activities and were comparatively much higher in R. mucronata. R. mucronata (86.50 ± 0.35%) showed much higher total antioxidant activity followed by R. apiculata (73.34 ± 0.90%) and R. annamalayana (69.35 ± 0.56%) at 100 μg/mL concentration. The antimicrobial activity was higher in R. mucronata and R. apiculata than R. annamalayana as evident by the presences of phenolic N–H and OH components found in mangroves tea. Therefore mangroves are rich source of tea, biochemical constituent, phytochemical, antioxidant and antibacterial properties. The extract contained polyphenolic and other bioactive compounds can be used for herbal drug formulation and nutraceutical.

In order to examine pollen deterioration in mangrove sediments, surface sediment samples were collected from 4 different mangrove communities, placed in nylon gauze bags, and then buried back into their own vegetation in October 2010. At periods of 2, 4, and 6 months after burial, sediment bags were retrieved and examined. At each recovery, palynomorph percentages and concentrations were calculated as a means to investigate degradation rates of deposited palynomorphs and some physical factors affecting their preservation. It was found that although mangrove sediments are assumed to represent perfect depositional environments for the preservation of mangrove pollen due to the anoxic conditions, a high potential for loss of pollen was observed. Palynomorphs decayed more rapidly in the Ceriops tagal – Bruguiera spp. community, whereas this process seems to proceed at a slower rate in the Rhizophora apiculata – Bruguiera spp. community, possibly controlled by differences in sediment pH, salinity, grain size, and organic matter. The good pollen preservation of Rhizophora apiculata and Sonneratia alba in their own plant communites allow them to act as useful indicators of the forest communities in which they are dominant. On the other hand, quantitative compositional reliabilities of pollen from Avicennia alba , Bruguiera spp., and Ceriops tagal , tended to weaken by their progressive deterioration and poor preservation. However, a long term-experiment is still necessary to achieve a more accurate estimation of biases from such important taphonomic factors.

Aim α-Glucosidase is the key intestinal enzyme having clinical relevance in the treatment of diabetes mellitus. Therefore, in the present investigation an attempt was made to evaluate the inhibitory effect of medicinal mangrove species Rhizophora apiculata on α-glucosidase. Methods The leaf materials of R. apiculata were extracted with five different solvents viz., toluene, chloroform, ethyl acetate, ethanol, and methanol and their phytochemical constituents were qualitatively analyzed. Different concentrations of extracts (2.5, 10, 40, and 80 μg/ml) were used to determine the in vitro α-glucosidase inhibitory action. The enzyme kinetics of effective extract was determined by Lineweaver Burk plot analysis. The metabolites in the effective ethanolic extract of R. apiculata (EtOH-RA) were also fractionated and identified by HPLC–MS. Then, molecular interaction of these metabolites with modeled α-glucosidase was studied using Auto Dock. Results The quantitative phytochemical studies showed a huge amount of total alkaloids (250.53±0.51 mg/g) present in the EtOH-RA which exhibited significant α-glucosidase inhibitory activity compared to other extracts. The dichloromethane and acid aqueous fraction also showed significant inhibition (P Conclusion This study concludes that EtOH-RA and its dichloromethane fraction act as an effective α-glucosidase inhibitor and have a potential in the management of diabetes.

The effect of dietary supplementation with Rhizophora apiculata leaf extract on innate immune response, survival rate, and mortality of the economically important ornamental clownfish, Amphiprion sebae against Vibrio alginolyticus is reported. When fed with 1%, 5%, and 10% enriched diets the specific growth rate (SGR) of challenged A. sebae decreased progressively while the feed conversion ratio (FCR) increased from weeks 1 to 4. The lysozyme, respiratory burst, complement and phagocytic activities significantly increased when infected fish were fed with 5% or 10% supplementation diet on weeks 3 and 4. The superoxide anion production increased significantly with 1%, 5% and 10% diets on weeks 3 and 4 while the serum bactericidal activity significantly increased with all enriched diets. The anti-protease activity registered a significant increase with 5% and 10% diets on week 3 while with all enriched diets on week 4. The maximum survival rate was 85% and 80% when the challenged fish were fed with 5% and 10% enriched diets, but it declined to 65% with 1% diet. A lower cumulative mortality of 15% and 20% was registered when infected fish were fed with 5% or 10% diets. The results suggest that feeding 5% or 10% R. apiculata extract supplementation diet positively enhance the immune response and improve the growth and survival rate of A. sebae against V. alginolyticus .

The Matang Mangrove Forest is the largest single mangrove forest in Peninsular Malaysia, covering an area of more than 40,000 ha. As a national treasure, it lies under the jurisdiction of both the federal and state authorities. Monitoring temporal changes of mangrove area on a large scale requires a more efficient tool. Remote sensing is often a reliable alternative to ground-survey methods that provides useful source of information and coverage that is timely and complete especially in mangroves areas where accessibility is difficult. In this study, status and changes of land use and land cover in the Matang Mangrove Forest during the past 18 years (1993–1999, 1999 to 2011 and 1993 to 2011) were determined using multi temporal satellites, and threats to the ecosystems were also identified. Classification of land use and land cover approach was implemented using the maximum likelihood classifier (MLC) along with vegetation index differencing (NDVI) technique. Classification accuracy at 85.7%, 90%, and 88.9% with Kappa statistics of 0.82, 0.88, and 0.94 respectively for 1993, 1999 and 2011 image were obtained. The overall change in the area during the 18-year period indicated the loss of mangrove area at 8017.3 ha, while 2998 ha was newly planted or rehabilitated. The present study revealed that Rhizophora apiculata and Rhizophora mucronata are still being preserved, accounting to more than 80% of the total species. Temporal changes of the mangrove for the 18-year period showed that the mangroves were converted to water bodies at 31.1%, dry land forest at 30.6%, oil palm plantation at 18.9%, aquaculture at 11.1%, paddy plantation at 4.9%, horticulture at 3.1%, and urban settlement area at 0.3%. Threats towards the mangrove area were due to erosion, tree harvesting rotation, transitional forest, shrimp ponds, illegal agricultural activities and trespassing. The findings indicated an approach in collecting regular and appropriate mangrove forest area database and detection of activities that violate regulations. This will provide adequate information to the stakeholders in enhancing the management practise and for legislative purposes. Hence, combinations of these approaches has been proven to be adequate in detecting changes in the mangrove area and indicating the nature of the changes which will promote and enhance the management planning process towards sustainability of the Matang Mangrove Forest.

Natural hybridization is ubiquitous in flowering plants and it plays a crucial role in plant evolution and diversification. Among mangroves, the tribe Rhizophoreae (Rhizophoraceae) includes the largest taxonomic congregation exclusively of mangroves. However, the systemic distinction between two hybrids Rhizophora × annamalayana and Rhizophora × lamarckii remains imprecise, and their parental species are still uncertain. In the present study, AFLP analysis of Rhizophora genotypes namely Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa, R. × lamarckii and R. × annamalayana revealed 46.65% polymorphic bands. Jaccard similarity coefficient, Nei’s genetic diversity analysis (0.1851 ± 0.19) and Shannon’s diversity index (0.2790 ± 0.27) revealed low levels of genetic diversity among Rhizophora individuals. The cluster and phylogenetic analyses of AFLP and DNA sequence data evidently untangled the taxonomical controversy between R. × annamalayana and R. × lamarckii and demonstrated that the hybrids are simple F1s and there is no trace of backcrossing or introgression with their parental species. R. apiculata was found to be the maternal species of R. × annamalayana. Chloroplast (matK, rbcL) and nuclear (ITS) markers further substantiated the results of AFLP analysis.

Planting mangrove is an important work to respond to mangrove loss and erosion, a serious issue and exacerbated from climatic changes in coastal area of the Mekong Delta. However, the previous efforts have repeatedly been unsuccessful because planted seedlings have suffered complete loss due to the lack of protection from wave action and seasonal sediment movement. Two Melaleuca (Melaleuca cajuputi) fences (wave barrier and silt trap fences) were designed and set up for testing their effectiveness in assisting mangrove restoration in the erosion-prone area of the Kien Giang Province. The wave height of the shoreline behind the Melaleuca fence can reduced by 63% compared to the open coast. After 3 years, they retained from 45 to 47 cm of mud inside the fence line. The survival rate of Avicennia alba (62% and 44%) was much higher than that of Rhizophora apiculata (35% and 14%) in both two fenced treatments. Growth rate of Avicennia seedlings was also much higher than Rhizophora in both treatments. There was a significant statistical difference between live seedlings and growth of Rhizophora and Avicennia in the two fenced treatments. Wild seedlings of Avicennia started colonizing the fenced area after 1.5 years of fence construction and regenerated seedling density varied from 2300 seedlings/ha in to 7100 seedlings/ha after 3 years. Species richness of benthos inside 2 fenced areas approached that in the natural forest area 1.5 years after fence construction. The study demonstrates the high potential of using Melaleuca fences to facilitate regeneration of mangrove and improves coastal protection in Kien Giang Province.

Development of non-toxic or less toxic paints has become a target for researchers due to the awareness of the impacts from the use of toxic antifouling paints. One of the modern alternatives to produce an environmental friendly paint is by using natural products. This study investigated the mangrove, Rhizophora apiculata tannin derivatives (zinc tannate) for antifouling properties by incorporating the powdered extract with different amount in epoxy paint formulation. The antifouling activity of zinc tannate was proved by antifouling crystal violet assay and the specimens have been exposed in seawater environment. The initial and final weights of mild steel were recorded to obtain the mass accretion which indicates the weight of biofouling settlement over the specimen surface. The effectiveness of this antifouling agent depends on the amount of zinc tannate in the paint and their leaching rate in seawater. Low concentration of zinc tannate (2.736 mg/ml) was found sufficient to inhibit the growth of bacteria, Bacillus cereus .

The increase and accumulation of greenhouse gases such as CO2 was believed had caused global warming. Effort to decrease accumulation these gases is by increasing the role of mangrove forests with its ecological function as carbon sinks through good management system. To this date, very limited study on the mangrove carbon biomass using satellite data espescially in tropical region. Purpose of the research were to calculate the carbon biomass of mangrove vegetation above ground through allometric equations, and to build spatial model algorithms of each mangrove species in the region by remote sensing technology using Quickbird, Geo Eye and ALOS satellite data. The research use an exploratory field survey and purposive sampling method and was performed through the measurement of trunk diameter (DBH) of above ground mangrove biomass without damaging vegetation (non-destructive sampling). About 21 mangrove species in Kemujan Island with total mangrove biomass above ground consist of the trunk, branches, leaves: 182.4 ton or 91.2 tons of Carbon, with largest carbon storage in the trunk. The results of spatial algorithms mangrove carbon biomass for Kemujan island using Quickbird data are Ceriops tagal with Y= - 0.003(B2/B3)2 + 0.267(B2/B3) – 3.452; Rhizophora apiculata with the algorithm Y= 0.001(B2/B3)2 - 0.116(B2/B3) + 3.415; Bruguiera cylindrical with the algorithm Y= - 0.003(B2/B3)2 + 0.336(B2/B3) – 7.265; Xylocarpus granatum with algorithm Y= 0.000(B2/B3)2 - 0.058(B2/B3) + 2.101; Rhizophora mucronata with the algorithm Y= 0.000(B2/B3)2 - 0.022(B2/B3) + 1.941. Mangrove carbon biomass algorithm using Geo Eye satellite data at Parang island for Rhizophora mucronata Y = -0.0436(B2/B3)2 + 0.526 (B2/B3) – 1.4642; Bruguiera gymnorrhiza Y = - 0.0027 (B2/B3)2 + 0.0649 (B2/B3) – 0.2432 and Bruguiera cylindrical Y = - 0.0089 (B2/B3)2 + 0.0632 (B2/B3) – 0.0683. Total mangrove carbon biomass at Demak coastal area range from 2.9 – 44.74 ton. Algorithm of mangrove carbon biomass at Demak using ALOS-AVNIR satellite data for Avicennia marina was Y = - 79.18 ((B1-B2)/(B1+B2))2 + 31.35 ((B1-B2)/(B1+B2)) - 1.191. The research concluded that band rationing of Band-2 with Band-3 for Quickbird and GeoEye data and Band-1 with Band-2 for ALOS data as the spectral signature of mangrove chlorophyll pigment with wave length of 0.5 - 0.6μm as the best for mangrove carbon algorithms.

Antimicrobial prospective of dichloromethane and methanolic extracts of Rhizophora apiculata was to evaluate against urinary tract infective strains such as Escherichia coli , Staphylococcus aureus , Pseudomonas aeurginosa , Proteus mirabilis and Klebsiella pneumoniae , methanolic extract showed better quality results at 250–350 µg/ml against all strains. And minimum inhibitory concentration and minimum bactericidal concentration were recorded at 160 µg/ml concentration level against for four strains excluding S. aureus at 240 µg/ml. Six phytochemicals (cardiac glycosides, saponins, tannins, coumarins, quinines and steroids) present in methanolic extract. Two spots were separated in thin layer chromatography and identified as genistein and unidentified alkaloids in addition to showed antibacterial activity in the TLC bioautography overlay assay screening. Together with characterized the genistein and alkaloids for FT-IR spectrum and displayed the occurrence of active functional groups such as hydrogen, carbonyl, carboxylic and ketones. These findings advise that the mangrove metabolites might be a potential candidate for the individualization of novel templates for the development of new antimicrobial agents or combinations of drugs for chemotherapy.

Five new polyketide derivatives, 6′-hydroxypestalotiopsone C ( 1 ), acropyrone ( 2 ), bicytosporone D ( 3 ), waol acid ( 4 ), and pestalotiopene C ( 5 ), together with seven known metabolites ( 6 – 12 ), were obtained from extracts of the endophytic fungus Acremonium strictum , isolated from the mangrove tree Rhizophora apiculata . The structures of the isolated compounds were elucidated on the basis of comprehensive NMR and MS analysis. Compounds 6 , 7 , and 9 showed moderate cytotoxic activity against human cisplatin-sensitive (IC 50 values 27.1, 76.2, and 8.3 μM, respectively) and resistant A2780 cell lines (IC 50 values 12.6, 30.1, and 19.0 μM, respectively), whereas only 9 exhibited antibacterial activity against Staphylococcus aureus (MIC value 14.3 μM).

Pollen analysis supplemented with diatom and phytolith from the surface and sub surface sediments from Kanjani, Thrissur district, Kerala was analyzed to reconstruct the vegetation and climate during a major part of the Holocene. Prior to 7270 cal BP, core mangroves of the intertidal zone viz., Rhizophora apiculata, Rhizophora mucronata, Avicennia spp., and Ceriops decandra grew in the vicinity of the site as indicated by the presence of their pollen grains, although the sediments are devoid of phytoliths and diatoms. Mangroves expanded during 7270–3530 cal BP. The presence of diatoms and phytoliths (pooid, chloridoid and panicoid) indicate continuation of a warm and humid climate, and the monsoon reached its peak at this time span. Subsequently, mangroves declined but phytoliths and diatom were well represented. This phase might be linked with the decrease of southwest monsoon influence in this region. Differential preservation of pollen, diatoms, and phytoliths in the same profile at different depths suggests that analyses of more proxies would be useful for better understanding of climate and environmental change.

Indonesia has the largest area and the highest tree species richness but also one of the highest loss rates of mangroves worldwide. The Segara Anakan lagoon is a mangrove-fringed estuarine system in Java which is highly affected by deforestation, sedimentation, and land-use changes. The spatial variability of diversity, community composition, density, height, aboveground biomass and habitat complexity of the mangrove forest in relation to abiotic conditions was studied in 2014/2015. Vegetation characteristics were compared with those available from 2005/2006, and the effects of deforestation on the forest condition were assessed. In total, 15 mangrove tree species were recorded in 2015, six less than ten years ago. The two main areas of the lagoon, the central and eastern one, had a significantly different tree community composition. The central area was dominated by the palm Nypa fruticans and Aegiceras corniculatum and 74% of the ground was covered by the understorey plants Acanthus spp. and Derris trifoliata. Tree density, stand basal area, species number, aboveground biomass, and habitat complexity were significantly lower in the central area as a result of deforestation. Stand basal area and aboveground biomass decreased significantly over the 10 years as well as the density of Avicennia spp., Sonneratia spp., Ceriops spp., Aegiceras corniculatum, and Bruguiera spp. The eastern area was dominated by A. corniculatum and Rhizophora apiculata, and coverage with understorey plants was only 11%. The density of R. apiculata increased significantly over the 10 years as a result of natural regeneration and reforestation. The overall low tree height (2.8 m) and aboveground biomass (18.4 t dry mass ha−1) point to a young and degraded forest. In the central lagoon, mangrove reforestation is probably extremely difficult due to the strong expansion of understorey plants. It is assumed that ongoing deforestation will cause a further spread of understorey plants, a decrease in species number, tree density and habitat complexity. A decline in microhabitats and aboveground biomass can lead to a decrease of faunal species and biomass which in turn would influence nutrient cycling and impair the nursery function of the area. Also, important ecosystem services, particularly coastal protection against storms and prevention of coastal erosion are most likely affected.

Mangroves are natural halophytes confined to the tropical and subtropical coastal region of the world. Rhizophora apiculata is a small mangrove tree with a natural reservoir of many unknown salt tolerance mechanisms which is completely unexplored. In the present study, we cloned the full-length coding sequence of a putative vacuolar Na+/H+ exchanger from R. apiculata (RaNHX1). In-silico analysis predicted highly conserved signature domain, motifs such as cation/proton exchanger 1 (CPA1), Na+/H+ exchanger domain, amiloride-binding motif, and 12 transmembrane helices, which confirmed they are a member of plant NHX family. Transcript analysis of RaNHX1 revealed differential transcript regulation pattern in various tissues and under salt stress libraries. Total Na+ and K+ analysis in leaves, stem, and root tissues under salt stress revealed that leaves are major Na+ storage tissues in R. apiculata. The heterologous expression of pYES2.1-RaNHX1 construct in AXT3 yeast mutant strain showed partial complementation of sensitive phenotype under NaCl and KCl stress indicating their involvement in sequestering Na+ and K+. In slight alkaline condition, AXT3-RaNHX1 partially complemented the mutant phenotype under Na+ and K+ supplements, while at acidic pH phenotype was less conclusive. Total Na+ and K+ analysis of AXT3-RaNHX1 showed higher accumulation in yeast cells compared to AXT3 mutant in NaCl stress conditions. Taken together, this is a first attempt to functionally characterize RaNHX1 member from R. apiculata which may contribute to better understanding of salt tolerance mechanism in R. apiculata.

In order to accurately evaluate the contribution of mangrove forests in reducing the effects of climate change, a precise understanding of the carbon fixation capacity of mangrove trees is needed. However, a fully reliable method to estimate carbon fixation capacity has yet to be established. In this study, net carbon fixation of a representative mangrove tree in South-East Asia, Rhizophora apiculata, was estimated. It was calculated with two different procedures; the gas exchange analysis and the growth curve analysis methods. The gas exchange analysis method is based on calculated carbon values of the difference between photosynthetic absorption and respiratory emission. These two parameters were calculated by using photosynthetic rates of single-leaves in response to light and temperature and respiratory rates of trunk and branch in response to temperature. These monthly values were adjusted with monthly average measurements of light intensity and temperature to improve estimation accuracy. The value of annual net carbon fixation for 3, 4, 5 and 9 year-old forests was estimated to be 2.5–30.5 Mg C ha−1 yr−1. The values with the temperature modification increased by 9.3–21.3%, compared to those of 2.2–25.2 Mg C ha−1 yr−1 without the temperature modification. However, it was found that these estimated values were significantly higher than the results produced by the growth curve analysis method, which produced 1.1–35.2 Mg C ha−1 yr−1. Results of this study show that further work is required to improve the estimation accuracy for both the gas exchange analysis and growth curve analysis methods. There is a particular need to take into account the respiratory carbon emissions from the plant root for the former method and determination of the maximum biomass at the mature tree phase for the latter method.

Mangrove crabs as key ecosystem engineers may play an important role in the recovery process of storm-damaged forests. Yet, their response to storm disturbance is largely unknown. Here we compare the ground-dwelling brachyuran crab community of intact mangrove stands with that of typhoon gaps having experienced 100% tree mortality. Field work was conducted in two adjacent areas in Can Gio Biosphere Reserve, southern Vietnam. In each area, an 18–20 yr old monoculture Rhizophora apiculata stand served as control and was compared with typhoon gaps where downed stems had been removed or left on-site. The gaps were 14 and 20 months old when studied in the dry and rainy season 2008, respectively. Time-based sampling of ground-dwelling crabs with hand or shovel was conducted by 4 persons inside 100 m2 plots for 30 min (7 replicate plots per area, treatment and month). Abiotic (sediment pH, salinity, temperature, grain size, water content, carbon and nitrogen content), and biotic measures (e.g. canopy coverage, woody debris, number of trees, leaf litter) were also taken. Despite complete canopy loss, total crab abundance has not changed significantly (in contrast to biomass) and all 12 species found in the forest were also found in the gaps, demonstrating their robustness. Another 9 gap-exclusive species were recorded and average species number and Shannon diversity were thus higher in the gaps. Perisesarma eumolpe was the most abundant species, both in the forest and in the gaps, and a shift from sesarmids (typical forest species) to ocypodids (generally more prominent in open areas) has not occurred. The persistence of litter-feeding sesarmid crabs prior to the re-establishment of a mangrove canopy is likely to depend on the availability of woody debris on the ground of the gaps, fuelling a mangrove detritus based food web, rather than one based on microphytobenthos and deposit-feeding ocypodids. The presence of burrowing crabs in the gaps suggests that important ecosystem engineering activities are still performed. However, bioturbation may be reduced as crab biomass and body size were smaller in the gaps. Follow-up assessments and field experiments are needed to understand the crabs' role in processing the woody debris, their long-term community dynamics and possible feed-backs between species shifts and gap regeneration.

Long terminal repeat (LTR) retrotransposons are predominant mobile elements that play important roles in plant genome evolution. Here, we isolated the first putative complete Ty1/ copia -like retrotransposon of 6303 bp in mangrove Rhizophora apiculata , named RARE-1 . RARE-1 was homologous to the soybean retroelement 1 ( SORE-1 ) and exhibited abundant cis -regulatory motifs involved in various stress responses in its LTRs. Using the sequence-specific amplification polymorphism (S-SAP) technique, we obtained a total of 112 bands for two R. apiculata populations from Hainan, China and Ranong, Thailand. The Hainan population showed slightly higher S-SAP polymorphism but fewer unique bands than the Ranong population. Moreover, the Hainan population also had significantly more copies of RARE-1 than the Ranong population as revealed by quantitative real-time PCR (qPCR). Our results suggested that RARE-1 might have been domesticated in the R. apiculata genome, as a result of the long-term evolution of mangroves under the extreme environment.

Mangroves in the Ayeyarwady Mega Delta of Myanmar are crucial for the ecology, society and economy of this country. At the beginning of May 2008, a severe cyclonic storm, Cyclone Nargis, struck the Ayeyarwady mangroves. Since that time, the present long-term study has been exploring the dynamics of post-cyclone mangrove vegetation. Every year since the 2008 cyclone, a census has been taken of 60 permanent plots (each measuring 10 m × 10 m) in six mangrove communities in order to predict trends in their long-term recovery. Each selected mangrove community was dominated by either Avicennia officinalis, Bruguiera sexangula, Excoecaria agallocha, Heritiera fomes, Rhizophora apiculata, or Sonneratia caseolaris. Mortality among the Rhizophoraceae group, including B. sexangula and R. apiculata adult individuals, was more than 90%, whereas for other species belonging to the non-Rhizophoraceae group, it was less than 20%. Based on the 5-year assessment, the mangroves showed considerable resilience after the catastrophic cyclone disturbance. However, the recovery potential of specific species varied. In particular, communities where R. apiculata dominated demonstrated slow recovery processes. The reasons for the vulnerability of this species of Rhizophora to cyclone disturbance is assumed to be the result of three indirect post-cyclone consequences: high mortality caused by limited sprouting ability after wind-induced disturbance; erosion that occurred in the stressful habitat on riverbank mud flats with frequent tidal inundation; and delayed phenology after the catastrophic disturbance. The attempt to generalise the recovery rate of mangroves based on the crown closure of the six dominant mangrove communities explored in this study showed a recovery rate of 61.06% during the 4 years after Cyclone Nargis. The demonstration of these patterns and processes among the most dominant mangrove species after the cyclone disturbance should therefore provide reliable information to forest managers, ecologists and local people, helping them make management decisions regarding measures for mangrove restoration.

The focus of the study is to compare the antibacterial efficacy of silver nanoparticles (AgNPs) fabricated by exploiting biological (a mangrove plant, Rhizophora apiculata) and chemical means (Glucose). The synthesized nanoparticles were characterised using UV-visible absorption spectrophotometry (UV-vis), Fourier transform Infra-red Spectroscopy (FTIR) and Transmission electron microscopy (TEM). Biologically synthesized silver nanoparticles (BAgNPs) were observed at 423 nm with particle sizes of 19-42 nm. The chemically synthesized silver nanoparticles (CAgNPs) showed a maximum peak at 422 nm with particle sizes of 13-19 nm. An obvious superiority of the antibacterial potency of BAgNPs compared to the CAgNPs as denoted by the zone of inhibition (ZoI) was noted when the nanoparticles were treated against seven different Microbial Type Culture Collection (MTCC) strains. The current study therefore elucidates that the synthesized AgNPs were efficient against the bacterial strains tested.

Avicennia marina saplings were established within a restoration area at Sg. Hj. Dorani, Malaysia between May and August 2010. Sapling establishment was achieved following the construction of segmented and hard breakwater as mitigating measure against coastal erosion. Geostructures known as brush faschines were installed within the restoration area as secondary sediment and seed traps. There was a steady increase in the sand content of the soil from 5% in November 2008 to 18% in May 2010. The dominant soil content was silt but it fluctuated and declined slightly over the same period, between 80% in November 2008 and 72% in May 2010. The accreting shoreline behind the breakwater had stabilised within 18 months. Subsequently, the first batch of A. marina wild seedlings or wildings was established on the mud surface in September 2009. Only about 10% of these wildings survived and showed high survival rate (90%) over the next eight months. Wildings that were naturally established near mother trees showed good growth performance. No wilding was established after the fruiting season in August 2010 as all seeds that were dispersed into the restoration area were washed away by September 2010. Tall, A. marina wild saplings (1 m) planted within the restoration area showed higher survival rate (80%) compared to planted saplings of Rhizophora apiculata (30%). Final planting of a thousand 1 m tall A. marina wild saplings was carried out from June 2010, in clumps of 20 and in 1 m × 1 m spacing. By the end of September 2010 clusters of regenerating A. marina mangroves about 1.5 m tall were successfully established on the accreting coastline.

The large amounts of leaf litter produced by tropical mangrove forests serve as a major food source for the benthic fauna. The reasons for the preferential consumption of mangrove leaves by crabs are unclear as yet. We investigated the diet, food preferences and consumption rates of 8 dominant grapsoid crab species ( Perisesarma spp., Episesarma spp., Metopograpsus latifrons , and Metaplax elegans ) in mangroves of Segara Anakan, Java, Indonesia, by means of stomach-content analysis and feeding experiments. Leaves from the five most abundant mangrove tree species ( Aegiceras corniculatum , Avicennia alba , Ceriops decandra , Rhizophora apiculata , and Sonneratia caseolaris ) were analyzed for organic carbon, total nitrogen, δ 13 C, δ 15 N and amino acids and hexosamines. This study is the first that investigated crab food preferences related to the nitrogen compound composition of leaves. Our results show that Episesarma spp. and Perisesarma spp. are omnivorous crabs which mainly feed on detritus, mangrove litter and bark, and on a small amount of roots, algae and animal matter whereas M. elegans is a detritus feeder. In feeding experiments with green, yellow and brown leaves Perisesarma spp. and E. singaporense had the highest consumption rates for brown leaves of R. apiculata and S. caseolaris , and for green leaves of A. alba . Preferred leaves were characterized by a high amount and/or freshness of nitrogenous compounds and their biochemical composition was significantly different from that of disliked leaves (all leaves of A. corniculatum and C. decandra , green and yellow leaves of R. apiculata and S. caseolaris ). The presence of the hexosamine galactosamine found only in brown leaves indicates that bacteria contribute to the amount of bioavailable nitrogen compounds. We infer that the nitrogen compound composition rather than the C/N ratio alone is a determinant for bioavailability of mangrove leaves and hence may partly explain the crabs' food preferences.

article For mangroves with almost no tidal influence and a subsequent mosaic vegetation structure we describe the relation between propagule predators and both vegetation structure and environmental factors on a vegetation assemblage or 'forest patch' level. We then report the interaction between natural propagule predation and human influence. In different forest patches dominated by Avicennia officinalis, Excoecaria agallocha, Lumnitzera racemosa, Rhizophora apiculata or R. mucronata or in open or mixed areas identified from aerial photographs, the predation on propagules of A. officinalis, B. gymnorrhiza, R. apiculata and R. mucronata was monitored in a total of 24 experimental plots (3 per forest patch). Relationships to environmental factors (topography, water level, rainfall and season) on the level of predation were investigated. The highest predation intensity by crabs was on A. officinalis propagules, and in E. agallocha forest patches. Predation by crabs, snails, insects and mammals was observed, and the significant differences in predation intensity across species and across forest patches were explained directly by propagule predator identity and abundance, and by the interaction between rainfall, water level and microtopography. We illustrated how hydrography changes alter the behaviour of propagule predators and play a role in the shaping of vegetation structure by reconstructing the lagoon water level of a site over a period of 50 years based on rainfall data. This time frame covered both a condition without and with human impacts, and past and present propagule predation settings were confronted with the simulated hydrology. The importance of spatial and temporal microhabitat variations in opening multiple successional pathways in vegetation dynamics is illustrated, and is highly relevant for ecosystems with unpredictable or short-lived (b20 years) patchy vegetation structures and microhabitats.

Experiments were conducted in an outdoor facility to quantify growth responses of six mangrove species to rates of dissolved inorganic nitrogen and phosphorus supply mimicking the range of N and P mineralization rates in natural soils. Growth of all six species on nitrogen was nonlinear. Stem extension rates of Rhizophora apiculata and Xylocarpus granatum were enhanced to the highest rate of N supply (50 mmol m − 2 d − 1 ); Bruguiera gymnorrhiza , Avicennia marina , and Xylocarpus moluccensis stem growth leveled off by 10 mmol m − 2 d − 1 . Stem growth of Ceriops tagal peaked at 24–26 mmol N m − 2 d − 1 . Except for A. marina and C. tagal , rates of biomass increase declined at the highest supply rate, indicating NH 4 + toxicity. At different rates of P supply, stem extension rates and rates of biomass increase of R. apiculata and C. tagal best-fit Gaussian curves and B. gymnorrhiza stem growth and biomass increase best-fit sigmoidal and Gaussian curves, respectively; X. moluccensis stem and biomass growth increased linearly, but stem and biomass growth rates of A. marina did not vary in relation to P supply. Stem growth of X. granatum was Gaussian but rates of biomass increase best-fit a quadratic equation. Changes in leaf and root N and P content mirrored the growth responses. As rates of N and P mineralization in natural mangrove soils overlap with the lowest rates of N and P supplied in these experiments, the growth responses imply that mangroves are intrinsically nutrient-limited at mineralization rates often encountered in nature. Such species specificity may have significant implications for recruitment success and the establishment of species gradients within mangrove forests.

The wasted barks of Rhizophora apiculata mangrove from charcoal industry were explored as a potential source in producing tannins-based adsorbent for heavy metal ions. The polyflavonoid tannins extracted from these barks were subjected to FTIR and solid-state NMR analysis. The mangrove tannins contain high proportion of procyanidins to prodelphinidins with predominant C4–C8 interflavonoid linkages. The performance of mangrove tannins in removing copper (II) and lead (II) were evaluated. Effecting parameters like initial pH, initial concentrations of metal ions and contact time were investigated. The adsorption equilibrium data was fitted with Langmuir, Freundlich, Sips and Dubinin–Radushkevich isotherm models. Mangrove tannins-based adsorbent showed monolayer adsorption capacity of 8.78 mg/g for copper (II) and 31.32 mg/g for lead (II) in which the adsorption processes were found to follow pseudo second-order kinetic reaction. The metal ions could interact with the hydroxyl groups of mangrove tannins through an ion exchange and/or complexation process.

A mathematical model was developed to simulate the growth dynamics of monospecific stands of the marine mangroves ( Rhizophora apiculata ), based on physiological and morphological processes. Six variables to describe the tree organs and three morphological variables to illustrate the growth pattern were selected and incorporated in the model. The growth pattern was described by using a series of mathematical relationships. Net tree growth was derived from the combined effect of photosynthesis, respiration, and mortality. Net primary production was allocated to the tree organs based on their allometric ratios. Coefficients reported in literature were used to simulate the life history and demographics of R. apiculata . Initial diameter at breast height ( DBH ), daily global radiation and mean air temperature are some of the inputs that were used to calculate the biomass and demographic parameters, using daily time steps. The model was capable of simulating the growth dynamics of R. apiculata stands at lower latitudes, with reasonable accuracy ( R 2 ≥ 0.80). However, the predictions at higher latitudes exhibited unsatisfactory model fits. This discrepancy in observations at higher latitudes is probably due to other factors like rainfall distribution, soil structure, which were not incorporated in the model structure.

Total DNA of Rhizophora apiculata , a salt-resistant seashore plant, was introduced into Capsicum annuum cv. via pollen tubes formed after self-pollination. The transformed progenies showed obvious stronger salt tolerance compared with the control. About 55% of the transgenes can survive, flower, and fruit when grown on the beach and watered directly with seawater. By contrast, no control survived under the same condition. Further analyses revealed a specific protein band of 17.5 kDa on protein SDS-PAGE gel and a specific DNA band of 1.1 kb in RAPD analyses. These results indicate that it is feasible to introduce exogenous DNA through pollen tubes, and that the improved salt tolerance of the progenies of transformed plants is related to genomic change.

Depolymerisation of mangrove Rhizophora apiculata bark extracts in the presence of phloroglucinol nucleophiles in ethanol was carried out. The flavan-3-ols and their phloroglucinol adducts were separated using reversed phase liquid chromatography (HPLC). The HPLC analysis of mangrove R. apiculata showed that catechin was the most common component of the flavanoid monomers. The antioxidant activities of these mangrove tannins were evaluated and compared with several commercial tannins by using reducing power, DPPH and ABTS assays with butylated hydroxytoluene, BHT and l -(+)-ascorbic acid as standards. All tannins had reducing power and percentage scavenging activities similar to the (+)-catechin and l -(+)-ascorbic acid standards. In the DPPH assay, >90% of the maximum scavenging activity was attained at 30 μg ml −1 . Mangrove tannins had stronger antioxidant activity than the BHT standard in the DPPH assay. The results of the ABTS assay were correlated with the DPPH assay. Scavenging activity in the ABTS assay increased as the tannin concentration increased, up to a plateau at 50 μg ml −1 .

The impact of small-scale cutting of mangroves by family groups was examined in three high-salinity forests on the dry tropical, north coast of Timor Leste. Before logging, these forests were characterized by moderately dense stands (3633–9610 stems ha−1) of Ceriops tagal, Rhizophora apiculata, Bruguiera gymnorrhiza, and Avicennia marina, with average basal areas of 13–34 m2 ha−1, total above-ground biomass of 51–221.5 t ha−1, canopy cover of 61–73%, and leaf area index (LAI) of 4.9–5.4 m2 leaf area m−2 ground area. Approximately 1 year after the start of harvesting, these forests experienced a 30–50% decline in live stems and a 46–86% loss of above-ground biomass with more canopy gaps between less dense, smaller trees. There was some evidence of selectivity of trees 5–15 cm dbh in size, interpreted as a trade-off between cutting trees small enough for women and children to carry but large enough to warrant cost/benefit of selling for firewood. Concentrations of most particulate nutrients increased in surface soils in the harvested stands, reflecting bark, leaves, twigs, and small branches discarded on the forest floor. Interstitial concentrations of dissolved sulfide, metals, and ammonium also increased due to enhanced soil desiccation (evidenced by increased salinity) and decline in solute uptake and O2 translocation to live roots. Rates of anaerobic soil metabolism (sulfate reduction) declined after the onset of cutting, attributed to the decline in live roots and their metabolic activities. These cutting operations, although small-scale, are unsustainable as these forests are likely to be slow-growing in such highly saline soils. A community-based approach to conservation and sustainable management of the remaining mangrove forests of Timor Leste is recommended.

The spatial variations of meiofauna population density and the assemblage of free-living marine nematodes in areas with Avicennia marina and Rhizophora apiculata cover of Pichavaram and Parangipettai (southeast coast of India) are described. Seven meiofauna taxa were recorded, with maximum density of meiofauna (890 ind. 10 cm −2 ) being recorded in an area with A. marina cover. Nematodes accounted for up to 93.1% of the total densities; other common taxa were foraminifera and polychaeta. A total of 44 species of nematodes belonging to 36 genera and 20 families were recorded. Of these, 37 species belonging to 30 genera and 17 families were recorded from Pichavaram mangrove and 14 species belonging to 10 families from a nearby artificial mangrove environment. While 16 species were common to both A. marina and R. apiculata cover, 15 species were restricted to areas with A. marina cover and 13 to areas with R. apiculata cover. Dorylaimopsis sp. was the abundant genera in areas with A. marina cover and Daptonema sp. in areas with R. apiculata cover. Only three species were common in all the five stations. Epistrate-feeders were the most abundant nematodes in areas with A. marina cover and deposit-feeders/ciliate feeders in areas with R. apiculata cover.

Annual variations from 1982 to 1999 of a wide range of trace elements and reconnaissance Pb isotopes (Pb-207/Pb-206 and Pb-208/Pb-206) were analyzed by solution ICP-MS on digested ash from mangrove Rhizophora apiculata, obtained from Leizhou Peninsula, along northern coast of South China Sea. The concentrations of the majority of elements show a weak, declining trend with growth from 1982 to 1999, punctuated by several high concentration spikes. The declining trends are positively correlated with ring width and negatively correlated with inferred water-use efficiency, suggesting a physiological control over metal-uptake in this species. The episodic metal concentration-peaks cannot be interpreted with lateral movement or growth activities and appear to be related to environmental pollution events. Pb isotope ratios for most samples plot along the 'Chinese Pb line' and clearly document the importance of gasoline Pb as a source of contaminant. Shale-normalised REE + Y patterns are relatively flat and consistent across the growth period, with all patterns showing a positive Cc anomaly and elevated Y/Ho ratio. The positive Ce anomaly is observed regardless of the choice of normaliser, in contrast to previously reported REE patterns for terrestrial and marine plants. This pilot study of trace element, REE + Y and Pb isotope distribution in mangrove tree rings indicates the potential use of mangroves as monitors of historical environmental change. (c) 2006 Elsevier B.V. All rights reserved.

Total phenolics content, free radical scavenging activity, reducing power, and antioxidant activity of the pyroligenous acid from a mangrove plant, Rhizophora apiculata were evaluated. Dichloromethane extraction of the raw pyroligneous acid successfully yield 2 extracts, i.e. concentrated pyroligneous acid (CPA) and concentrated pyroligneous acid extract (CPAE). Phenolic contents in CPAE and CPA, expressed as (±)-catechin equivalents/g of the sample were 5465 ± 367 mg and 2502 ± 152 mg, and expressed as gallic acid equivalents/g of the sample were 2919 ± 209 mg and 1348 ± 90 mg, respectively. CPAE exhibited superior free radical scavenging activity with EC 50 value = 0.1235 mg/ml, or 80.96% of free radical scavenging capability. The ferric reducing power of CPAE was approximately 3.7, 5.1, 6.1, and 21.3 times higher than that of ascorbic acid, BHA, BHT and alpha-tocopherol. In phosphomolybdenum assay, CPAE showed the greatest antioxidant efficacy ( A 695 = 1.278) compared to those of CPA and different standards. In addition, the free radical scavenging activity, ferric reducing power and total antioxidative activity of CPAE and CPA showed positive correlation with their total phenolic content with R 2 values ranging from 0.9624 to 0.9979.

An experiment was conducted for 8 weeks at the Cantho University, Vietnam, to determine the acceptable level of mangrove leaf litter load and its effect on water quality, growth and survival rate of tiger shrimp ( Penaeus monodon ). Shrimps were cultured in plastic tanks containing 50 L of brackish water (salinity of 15‰). Leaf litter of Rhizophora apiculata , Avicennia officinalis , Excoecaria agallocha and Acacia auriculiformis were loaded to tanks at rates of 0.0 (control), 0.125, 0.25, 0.5, 1.0 and 2.0 g L − 1 with and without aeration. Tiger shrimp post-larvae (PL; 0.05 ± 0.01 g) obtained from the shrimp hatchery of Cantho University were stocked at a density of 20 PL per tank and fed with pelleted feed containing 38% protein at a rate of 10% body weight (BW) day − 1 . The high leaf-loading rates significantly reduced dissolved oxygen (DO) and survival rates of shrimp in the non-aerated treatments, and all shrimps died after 2 days in the treatments with loading rates above 0.5 g L − 1 . Leaf litter loads significantly increased tannin content, chemical oxygen demand (COD), H 2 S and pH in the aerated treatments. Stepwise regression analysis showed COD, tannin and H 2 S concentrations had negative effects on shrimp growth in the aerated treatments. Tannin concentration was found to be highest in the treatments with Excoecaria (32 mg L − 1 ) and Avicennia (24 mg L − 1 ) leaves. However, there were no significant differences in growth and survival rates of shrimp among the aerobic treatments loaded with different leaf types. The results of this study showed that moderate load of mangrove leaves could play an important role in promoting shrimp growth and survival in aerobic condition. Mangrove leaves at a loading rate of 1 g L − 1 positively influenced both the survival and growth rate of shrimps.

Carbon and nitrogen budgets for the leaf-eating crab, Neoepisesarma versicolor, were established for individuals living on pure leaf diets. Crabs were fed fresh (green), senescent (yellow) and partly degraded (brown) leaves of the mangrove tree Rhizophora apiculata. Ingestion, egestion and metabolic loss of carbon and nitrogen were determined from laboratory experiments. In addition, bacterial abundance in various compartments of the crabs’ digestive tract was enumerated after dissection of live individuals. Ingestion and egestion rates (in terms of dry weight) were highest, while the assimilation efficiency was poorest for crabs fed on brown leaves. The low assimilation efficiency was more than counteracted by the high ingestion rate providing more carbon for growth than for crabs fed green and yellow leaves. In any case, the results show that all types of leaves can provide adequate carbon while nitrogen was insufficient to support both maintenance (yellow leaves) and growth (green, yellow and brown leaves). Leafeating crabs must therefore obtain supplementary nitrogen by other means in order to meet their nitrogen requirement. Three hypotheses were evaluated: (1) crabs supplement their diet with bacteria and benthic microalgae by ingesting own faeces and/or selective grazing at the sediment surface; (2) assimilation of symbiotic nitrogen-fixing bacteria in the crabs’ own intestinal system; and (3) nitrogen storage following occasional feeding on animal tissues (e.g. meiofauna and carcasses). It appears that hypothesis 1 is of limited importance for N. versicolor since faeces and sediment can only supply a minor fraction of the missing nitrogen due to physical constraints on the amount of material the crabs can consume. Hypothesis 2 can be ruled out because tests showed no nitrogen fixation activity in the intestinal system of N. versicolor. It is therefore likely that leaf-eating crabs provide most of their nitrogen requirement from intracellular deposits following occasionally ingestion of animal tissue (hypothesis 3). 2005 Elsevier Ltd. All rights reserved.

This allometric data set gives total biomass in kg (log total biomass =2.523 log GBH −1.943 ); total above-ground biomass (log above-ground biomass =2.420 log GBH −1.832 ); total below-ground biomass (log below-ground biomass =2.611 log GBH −3.454 ) as well as stilts (log stilt biomass =2.546 log GBH −2.945 ); trunk (log trunk biomass =2.477 log GBH −2.050 ) and leaf biomass (log leaf biomass =0.133 log GBH −0.728 ), from girth at breast height (GBH, in cm) of the mangrove Rhizophora apiculata Blume. A comparison is made with three other previous studies. The below-ground data set is unique: there is only one other study on root biomass but the stilts were not separated from the below-ground roots. This is the second reported data set for total biomass and the two allometric regression equations are almost identical. Based on the few direct comparisons available, it is suggested that allometric equations for R. apiculata may not be very site specific but further studies would be needed to confirm this. Partitioning of biomass is very variable for the smaller trees (GBH