Spatio-temporal variation of water salinity in mangroves revealed by continuous monitoring and its relationship to floristic diversity

Salinity is among the most critical factors limiting the growth and species distribution of coastal plants.Water salinity in estuarine ecosystems varies temporally and spatially,but the variation patterns across different time scales and salinity fluctuation have rarely been quantified.The effects of salinity on floristic diversity in mangroves are not fully understood due to the temporal and spatial heterogeneity of salinity.In this study,we monitored water salinity at an interval of 10-min over one year in three mangrove catchment areas representing the outer part,middle part,and inner part respectively of Dongzhai Bay,Hainan,China.The number of mangrove community types and dominant mangrove species of the three catchment areas were also investigated.We found that the diurnal variation and dry-season intra-month variation in water salinity were driven by tidal cycles.The seasonal variation in water salinity was mainly driven by rainfall with higher salinity occurring in the dry season and lower salinity occurring in the wet season.Spatially,water salinity was highest at the outer part,intermediate at the middle part,and lowest at the inner part of the bay.The intra-month and annual fluctuations of water salinity were highest at the middle part and lowest at the outer part of the bay.The number of mangrove community types and dominant species were lowest at the outer part,intermediate at the middle part,and highest at the inner part of the bay.These results suggest that the temporal variation of water salinity in mangroves is driven by different factors at different time scales and therefore it is necessary to measure water salinity at different time scales to get a complete picture of the saline environment that mangroves experience.Spatially,lower salinity levels benefit mangrove species richness within a bay landscape,however,further research is needed to distinguish the effects of salinity fluctuation and salinity level in affecting mangrove species richness.

Comprehensive Risk Assessment of Sea Level Rise and Tropical Cyclones in Dongzhaigang Mangroves,China

Mangroves play a pivotal role in tropical and subtropical coastal ecosystem,yet they are highly vulnerable to the effects of climate change,particularly the accelerated global sea level rise(SLR)and stronger tropical cyclones(TCs).However,there is a lack of research addressing future simultaneous combined impacts of the slow-onset of SLR and rapid-onset of TCs on China's mangroves.In order to develop a comprehensive risk assessment method considering the superimposed effects of these two factors and analyze risk for mangroves in Dongzhaigang,Hainan Island,China,we used observational and climate model data to assess the risks to mangroves under low,intermediate,and very high greenhouse gas(GHG)emission scenarios(such as SSP1-2.6,SSP2-4.5,and SSP5-8.5)in 2030,2050,and 2100,and compiled a risk assessment scheme for mangroves in Dongzhaigang,China.The results showed that the combined risks from SLR and TCs will continue to rise;however,SLRs will increase in intensity,and TCs will decrease.The comprehensive risk of the Dongzhaigang mangroves posed by climate change will remain low under SSP1-2.6 and SSP2-4.5 scenarios by 2030,but it will increase substantially by 2100.While under SSP5-8.5 scenario,the risks to mangroves in Dongzhaigang are projected to increase considerably by 2050,and approximately 68.8%of mangroves will be at very high risk by 2100.The risk to the Dongzhaigang mangroves is not only influenced by the hazards but also closely linked to their exposure and vulnerability.We therefore propose climate resilience developmental responses for mangroves to address the effects of climate change.This study for the combined impact of TCs and SLR on mangroves in Dongzhaigang,China can enrich the method system of mangrove risk assessment and provide references for scientific management.

The Toxic Effects of Strong Chlorin Disinfectant on Mangroves and Emission Thresholds

In this study, based on the simulated discharge results of chemical disinfectants, hypocotyl germination concentration gradient pre-test and concentration gradient determination experiment were set up respectively. Laboratory cultivation was conducted to compare and analyze the root germination and germination indexes, three mangrove hypocotyls of Kandelia candel (Linn.) Druce, Ceriopstagal C.B. Rob. and Bruguiera sexangula var. Rhynchopetalas’ efficiency of cumulative root germination, cumulative germination and the cumulative expansion of the second pair of leaves, one-way analysis of variance was used to obtain the tolerance threshold of three mangrove hypocotyls to strong chlorin disinfectant. The study determined that the by-products of strong chlorin disinfectant, the toxic threshold concentrations of Kandelia candel (Linn.) Druce, Ceriopstagal C.B. Rob. and Bruguiera sexangula var. rhynchopetala are close to 0.55 mg/L, 0.55 mg/L and 0.25 mg/L, respectively. This concentration range is lower than the average concentration of 1.183 mg/L of active chlorine emitted from strong chlorine concentrate during pond clearing in high-level shrimp ponds, indicating that transient emissions of strong chlorine concentrate during pond clearing can have a toxic effect on mangrove plants. The strength of tolerance of the embryonic axes of the three mangrove species to effective chlorine contamination was, Ceriopstagal C.B. Rob. stronger than Bruguiera sexangula var. rhynchopetala, and Kandelia candel (Linn.) Druce is the weakest.

Experimental study on the mitigation effect of mangroves during tsunami wave propagation

Mangroves are crucial for protecting coastal areas against extreme disasters such as tsunamis and storm surges.An experimental study was conducted to determine how mangroves can mitigate the tsunami wave propagation.The test was performed in a flume, where mangrove models were installed on a slope, and dam-burst waves were used to simulate tsunami waves. To study how mangrove forests reduce the impact of tsunamis, this paper measured the heights of the incoming waves under different initial conditions(tsunami wave intensity and initial water depth) and plant factors(arrangement and distribution density) and described the reduction process. The results show that, after passing through the mangrove, the tsunami bore height will decrease within a certain range as the initial water depth increases. However, there is no correlation between the increase of inundation level and the drop of water level. The bore height attenuation is more significant at higher density of mangroves,but after tsunami passing through the mangroves, the relative bore height will decrease. When the distribution density of mangroves is constant, the wave attenuation at different locations(before, on and after the slope)shows different relationships with the initial water depth and wave height for different models. The transmission coefficient(K_(i)) shows a parabolic correlation with its density. The proportion of the energy loss caused by the mangrove resistance to the total energy(E_(b)) is defined as C_(m2). The variation trend of C_(m2) corresponds to the tsunami wave energy attenuation rate(C_(a)) and K_(i).

Effects of Tropical Storm on Mangroves Forest Structure of Dongzhai Harbor in Hainan Island

The effects of tropical storm on the community structure of Sonneratia caseolaris-Sonneratia apetala(S.caseolaris-S.apetala) artificial mangroves and Ceriops tagal-Rhizophora stylosa(C.tagal-R.stylosa) natural mangroves were analyzed in Dongzhai Harbor in Hainan Island,and the results showed that the average tree height,crown width(CW) in east-west direction(E-W) and north-south direction(N-S) of S.caseolaris-S.apetala artificial mangroves were decreased by 2.8%,14.3% and 12.1% respectively,but the average clear bole height was increased by 60.0% after tropical storm.For C.tagal-R.stylosa natural mangroves,the average tree height and clear bole height were increased by 8.3% and 20.0%,but there was no change in CW(E-W) and CW(N-S).Therefore,tropical storm had greater effects on artificial mangroves than natural mangroves.After tropical storm,tree heights of different species increased in the following sequence:C.tagal>R.stylosa>S.apetala>S.caseolaris,and the sequence of effect degree on CW was C.tagal>R.stylosa>S.caseolaris>S.apetala,while it was C.tagal < R.stylosa < S.caseolaris < S.apetala for clear bole height.Under the effect of tropical storm,the average biomass loss and dry biomass loss of S.caseolaris-S.apetala artificial mangroves were 0.22 and 0.13 t/hm2 respectively,while there was a minimal biomass loss in C.tagal-R.stylosa natural mangroves.On the whole,the wind resistance of natural mangroves was better than artificial mangroves,and that of C.tagal was stronger than R.stylosa,while S.caseolaris was better than S.apetala.

Benthic Macrofaunal Assemblage in the Arid Zone Mangroves of Gulf of Kachchh-Gujarat

The total benthic macrofauna consisting of 62 species in 5 groups,viz. crustaceans(18),gastropods(17),bivalves(16),polychaetes(9) and fishes(2),was recorded in western Kachchh mangroves near Gujarat. The population densities of benthic macro-fauna ranged from 424 to 2393 ind.m-2,the diversity ranged from 1.84 to 2.45 bits ind.-1,the richness varied between 0.82 and 0.98,and the evenness varied between 0.64 and 0.81. Two maximum diversity values were recorded during winter and summer. The salin-ity ranged from 34 to 44,temperature varied between 17 and 37 ℃,and the acidity ranged from 7 to 8.9.

Fishery Resources in Arid Zone Mangroves in Gulf of Kachchh, Gujarat, Northwest Coast of India

The finfish and shellfish resources were assessed quantitatively and qualitatively in regard to their abundance in creek waters at three sites within a period of two years, fi＇om January 1999 to December 2000, in the western mangrove areas of Kachchh. The catch rate varied from 0.69 to 6.99kg·h^-1. It was low during monsoon （July to October）, which could be due to the freshwater-flow-induced salinity reduction in all the sites. Among 38 species recorded, 5 were shellfish and 33 were finfish. The spawning period of fishes was found to be during summer and early monsoon period （May to August）. Surface water temperatures varied from 17℃ to 37 ℃. Salinity values varied from 34 to 44 and the pH ranged between 7 and 8.9. Variation in dissolved oxygen content was from 3.42 to 5.85 mL L^-1. The high fishery densities in these semi arid mangrove creek areas were recorded during monsoon and early winter season.

Effect of cigarette smoking on human health and promising remedy by mangroves

This article reviews the evils of cigarette smoking and the promise of mangroves to cure them.Chemicals in cigarette smoke are leading cause of death to both smokers and nonsmokers.Plant is the potential source to produce medicine for almost all the diseases.Mangroves are promising as a novel source of anti-cancer drugs in regulating the cancer pathways and stimulating immunity in the body system.Research on medicine from mangroves for the treatment of cancer has not only been shown to have an effect on cancer,but also provided important methods for the study of cancer therapy and mechanism.This report may help to explore the medicinal properties of the mangroves.

Status,structure and environmental variations in semi-arid mangroves of India

The semi-arid mangroves of the Gulf of Kachchh,the largest ecosystems on the west coast of India,are poorly studied in terms of vegetation structure and environmental parameters in spite of their conservation significance.Therefore,it is necessary to document the structural features of these mangroves in view of ongoing coastal industrial development.Mangrove forest structure in 10 locations on the northern and southern coasts of the Gulf of Kachchh were assessed using the line intercept transect method.Descriptions included density of young and mature age classes,tree heights,diameters at breast height(DBH)and aboveground biomass,along with seven significant environmental variables.Mature tree densities ranged from 350 to 1567 ind.ha-1,while average height and girth at breast height ranged from 1.0 to 6.8 m and 3.0 to 137.0 cm,respectively.The majority of trees(55.6%)were in B 1.8 m height class followed by a 1.9 to 2.4 m class(25.1%).DBH was most often in class 2 cm or lower than that.Among the canopy index classes,more trees were recorded in class ≤2 cm.The regeneration density was greater than the recruitment class.This study indicates that the poor structural attributes of Avicennia marina Vierth.var.acutissima Stapf and Mold dominated mangroves are largely due to aridity induced by scarce and erratic rainfall and high soil and water salinities.The results should be valuable in conserving and sustainably managing these mangroves in the face of developmental activities.

Heavy Metal Distribution in Sediments of Muthupettai Mangroves, South East Coast of India

Core sediments from the Muthupettai mangroves on the southeast coast of India were analyzed for soil texture,total nitrogen,organic carbon,phosphorus and heavy metals(Fe,Mn,Cr,Cu,Ni,Pb,Zn and Cd).The distinct seasonal variation in the distribution of metals in the sediments was observed.The minimum concentration was recorded in river mouth and the maximum was in lagoon.High metal concentration in sediment was observed during monsoon and low concentration in summer.The total nu-trient in lagoon and river mouth was recorded in the range of 4.528 to 8.526 mg g-1 for organic carbon,2.213 to 10.5 mg g-1 for nitro-gen and 0.824 to 7.22 mg g-1.

Endophytic fungi of wild legume Sesbania bispinosa in coastal sand dunes and mangroves of the Southwest coast of India

Evaluation of 450 surface sterilized tissue segments of a seasonal wild legume, Sesbania bispinosa （Jacq.）, of coastal sand dunes and mangroves of southwest India yielded 546 isolates comprising 39 endophytic fungi with six dominant taxa （Aspergillus flavus, Aspergillus niger, Cladosporium tenuissimum, Fusarium moniliforme, Penicillium chrysogenum and morpho sp. 1）. A consortium of saprophytic, pathogenic and toxigenic fungi exists as endophytes in S. bispinosa. Number of segments colonized, number of isolates obtained, species richness and diversity were higher in S. bispinosa in mangroves compared to coastal sand dunes. Seeds yielded more fungal isolates, but species richness and diversity were low. In spite of low fungal colonization in root segments, the diversity was high. Up to 30-40 % endophytic fungi of S. bispinosa differed between coastal sand dunes and mangroves revealing partial host- and habitat-specificity. As S. bispi- nosa is extensively used as green manure and forage in southwest India, further studies especially on the bioactive compounds of its endophytic fungi might broaden its range of uses. In addition to conventional morphologicaltechniques, molecular tools would provide precise insight on the endophytic fungi of coastal sand dunes and mangroves.

Species and Distribution of Mangroves in the Fujian Coastal Area

On the basis of an investigation on the mangroves in Fujian from November 1998 to January 1999, the species composition, area, distribution, artificial afforestation of mangroves and the factors restricting the development of mangroves in Fujian are discussed in the paper. Some suggestions on how to develop mangroves in Fujian have been put forward.

Species diversity of birds in mangroves of Kundapura, Udupi District, Karnataka, Southwest Coast of India

We quantified species diversity of birds in mangroves at Kundapura from April-2010 to March-2013. We recorded 79 species of 36 families and 14 orders. Of these 71% are resident species, 22% are residential migrants and 8% are migratory. One endangered species, three near threatened species, and a few occasional visitors were re-corded. Species diversity and abundance of birds were greater during from October through May as there was availability of food, increased vegetation and the arrival of migratory birds. Minimum diversity was recorded from June through September owing to heavy rains, increased flow of water, limited availability of food and return of migratory birds.

Building a Methodology for the Design of an Environmental Services Payment Programme for the Mangroves of Mexico

Environmental Services Payment Programmes are not entirely new and they are more flexible than the usual command-and-control type of regulation. In the 1990s for example, an Environmental Services Payment programme was introduced to cope with the forestry system and pay benefits to farmers for the good that their forests would produce. This review examines the possibility of using Environmental Services Payment programmes for Mexican mangroves as they are an important resource against natural disasters, and reducing greenhouse gases in the Earth’s atmosphere, for example, and they are constantly invaded by the human race which impacts on their destruction. The review aims at constructing a methodology that can be applied to the implementation of Environmental Services Payment programmes. The value of this study is in aiming a straight arrow at the environmental problems outlined in this paper, problems that have not been fully resolved to date, especially in Mexico where it is not officially recognised that mangroves play an important role in the mitigation of greenhouse gases. Furthermore, Environmental Services Payment Programmes in Mexico have not pinpointed specific types of area. We conclude this paper with elaborating on our ten-point strategy for implementing Environmental Services Payment programmes which includes, in brief: 1) Fully accepting the importance of the mitigation of greenhouse gases via mangroves;2) designing a Environmental/Ecosystem Services Payment Programme with particular emphasis on Mexican mangroves;3) identifying specific environmental services and their level from local to international;4) formation and implementation of a system of “whoever benefits must pay”;5) building of a knowledge base of owners and others who benefit from environmental services;6) hypothetical models of particular Environmental Services Payment programmes must be constructed;7) clarifying who must pay;8) grouping all sectors that must pay;9) inspiring all actors to cooperate via 10) the impact of a Citizens’ Council, for example.

Mangroves Restoration and Observation in Kaohsiung Jhong-Dou Wetland

The ecosystems of Kaohsiung are rich and diverse. Examples of ecosystems include the tropical rainforest ecology, marine ecology of the coastal forests, and the estuary type ecology of mangrove forests. The Jhong-Dou Wetland Park is situated in the Jhong-Dou Redevelopment Zone, 2.5km from the Lover River Estuary. This area is defined by brackish aquatic environments--a mixture of fresh and salt water, and fulfills the criteria for mangrove restoration. It is expected that the current restoration project will recreate an epitome of the once-diverse, co-existing mangrove species of Kaohsiung＇s past, and improves upon the functions of environmental education. The initial mangrove species planned for restoration are the existing Kandelia obovata, Rhizophora stylosa, Avicennia marina and the Lumnitzera racemosa populations of the Kaohsiung area. These plants will be placed in experimental habitats that correspond to the unique micro-climates required for the growth of each species, and the mangrove-associated plants will also be restored concurrently in the terrestrial environments behind the mangrove forests. The process of restoration will be monitored by academia, as well as providing reference for subsequent mangrove environment restoration efforts. The main purpose of this research in these four mangrove species of this wetland park is to understand their adaptation to the rehabilitating environment, and be able to feedback these information to the design and maintenance team of the park. The research method is to observe and record their growing status, also execute a survey on the nearby mangrove habitation. The observation has started on December 1 st of 2010, and still has been continued carry on since then. From the research result, it shows that the A vicennia marina （Forsk.） Vierh. and Lumnitzera racemosa Willd. are the two species that had been well adapted to this wetland park. It was recommended to the Kaohsiung City Government that the restoration of the extinct Ceriops tagal and Bruguiera gymnorrhiza can be achieved through foreign species exchanges （the species must be identified before introduction）, and that plans for monitoring the flora and fauna in the park should be drafted to record the ecological alterations of the Jhong-Dou Wetlands. This will pronounce the ecological importance of Kaohsiung on a global, geographical scale. Lastly, the Government should draw up plans of mangrove forest maintenance in order to sustain the ecological and landscape recreational functions of the Jhong-Dou Wetland Park.

Geospatial Assessment for Sustainable Management of Mangroves in Kilifi Creek, Kenya

Mangroves are salt-tolerable trees that grow on zones parallel to the coastline along the creeks. They follow the mud flat accretions which are unvegetated areas consisting of sand or gravel that are either exposed or flooded by tides. They provide 70% of the wood requirement along the Kenyan Coast. Currently, there are no harvest plans of the mangroves and there is selective removal of suitable poles and most of the quality poles have been wiped out. This not only leaves the inferior species unsuitable for the market but also affects the quality of the forest. Moreover, areas that are suitable for mangroves growth have been occupied by human settlement and infrastructure, hence, there is a need of sustainable use of the mangroves so as to protect them from degradating and eventually extinction. To achieve this, geospatial techniques need to be employed in order to determine the spatial extent of the vegetation and devise methods and plans of managing them. The Kilifi Mangrove Forest creek is home to major six species: Avicennia marina, Ceriops tagal, Sonneratia alba J., Rhizophora mucronata, Lumnitzera racemosa and Bruguiera gymnorrhiza. This study showed that the most dominant species in the forest is Avicenna Marina which had a percentage stand of 25.6%. The less dominant species Lumnitzera racemosa and Heritiera littoralis had a stand of 0.10% which were restricted for harvesting in the analysis, they need to be protected so as to prevent its extinction in the forest which will affect the biodiversity and richness of the forest. Density and heights of the mangroves were considered so as to decide on which areas to do reforestation in order to protect the forest and help in preventing soil erosion. The final suitable area for harvesting after carrying out conditional and majority filter was 394 acres which are 9% of the total forest area. The total area most suitable for reforestation is 1151 acres which are 27% of the total Kilifi Mangrove Forest. A recommendation for proper harvesting plans should be made by identifying suitable sites for harvesting and areas which showed low mangrove stand density should be identified and necessary measures should be taken to restore them.

Comparative Adaptability Assessment of Two Mangroves from Indian Sundarbans: Some Biochemical Appearances

Comparative adaptability against salinity was assessed between the two wellknown mangroves (Avicennia marina and Heritiera fomes) from Indian Sundarbans in vitro. Occurrence of H. fomes is intermittent in and around of this mangrove swamp. A harmony has to maintain between ROS production and efficient scavenging of ROS by the plant itself for sustainability. In the present work, extent of salt tolerance was evaluated by mainly two ways: i) accumulation of free amino acids in the cytoplasm for proficient osmotic adjustment and ii) promoting elevated amount of antioxidants (both enzymes and secondary metabolites) with respect to substrate salinity. Occurrence of free amino acids (Alanine, Leucine and Proline) in A. marinaare well correlated (p ≤ 0.01) with the increasing salinity and H. fomes (Alanine and Phenyl Alanine) correlation value showed p ≤ 0.05. ROS scavenging reflected through ABTS, DPPH and Fe2+ chelating activity and results indicating that A. marina have some advantage over the other investigated taxa. Amount of phenols and flavonoids also designated the same. Additional number of isoforms of two antioxidant enzymes (peroxidase and super oxide dismutase) occurred in A. marina as the salinity enhanced, but in case of H. fomes, which was lacking. The experimental results might be designated towards the comfortable adaptability to A. marina, rather to H. fomes.

Inexpensive Method to Assess Mangroves Forest through the Use of Open Source Software and Data Available Freely in Public Domain

Mapping and assessment of mangrove environment are crucial since the mangrove has an important role in the process of human-environment interaction. In Indonesia alone, 25% of South East Asia's mangroves available are under threat. Recognizing the availability and the ability of new sensor of Landsat data, this study investigates the use of Landsat ETM + 7 and Landsat 8, acquired in 2002 and 2013 respectively, for assessing the extent of mangroves along the South Sulawesi’s coastline. For each year, a supervised classification of the mangrove was performed using open source GRASS GIS software. The resulting maps were then compared to quantify the change. Field work activities were conducted and confirmed with the changes that occurred in the study area.? Considering the accuracy assessment, our study shows that the RGB composite color-supervised classification is better than band ratio-supervised classification methods. By linking the open source software with the Landsat data and Google Earth satellite imagery that is available in public domain, mangroves forest conversion and changes can be observed remotely. Ground truth surveys confirmed that, decreases of mangroves forest is due to the expansion of fishpond activity. This technique could potentially allow rapid, inexpensive remote monitoring of cascading, indirect effects of human activities to mangroves forest.

Ecological Relationship between Mud Crab Scylla serrata (Forskal) and Mangroves and the Pattern of Utilization

The ecological relationship between mud crab Scylla serrata(Forskal)and mangroveswas described in this paper.Mangrove swamps are important reproductive places for mud crabs,where zoeae,megalopae,juveniles from 1st to 14th instar,adult crabs and ovigerous female crabswere found.Mangrove roots and the leaf litter are the shelters of the mud crab.The zoeae andmegalopae of mud crab can normally grow and develop on the plankton and debris that are well-supplied in mangrove swamps.There are a lot of Phascolesoma,Mollusca and Crustacea whichconstitute the delicious foods of the mud crab in mangrove swamps.The larger crabs have apreference for Ostrea,Balanus and Vignadula which usually amply adhere and endanger themangroves,so the mud crab is helpful for the development of the mangrove communties.Finallya pattern of ecological culture of the mud crab in mangrove swamps was suggested.

Study of Bacterial Diversity of Mangroves Rhizosphere

Microbial diversity has been an important facet of scientific research, since microbes promise a plethora of biomolecules which are otherwise not found in nature. Microbes are subjected to high level of competition for survival in the environment, and hence develop mechanisms of defense. The biomolecules produced by these microbes as part of their defense or survival mechanism, are of importance for human and animal drugs and many other industrial and environmental applications. The marine counterparts of these terrestrial microbes have yet higher potential, since the marine environment has higher biotic and abiotic stresses, leading to new molecule discovery. In the current study, a bacterial diversity study of the culturable bacteria of the mangrove rhizosphere of Avicennia marina has been undertaken, to understand the flora diversity. Mangroves are unique ecosystems which are under a combination of marine and terrestrial influence. Mangroves are seaward, inland and also found in creek areas. This diversity in their habitat, leads them to produce variable root exudates, which support the growth of different types of organisms. This study has revealed that certain species are dominant in these ecosystems irrespective of the biotic and abiotic stresses, whereas certain species appear only at neutral pH. The study will help select organisms for further biomolecule discovery programs, based on their environment of isolation and other growth parameters.