Mangrove Associate Species Research Articles

Mangroves and their Associates in Metal-Rich Soils in Candelaria, Zambales Province, Philippines

The Philippines, an archipelagic nation in Southeast Asia, has a coastline of over 18,000 km. and hosts at least 50 % of the world’s 65 mangrove species. Mangrove ecosystems are vital in mitigating heavy metal pollution; however, their resilience is compromised in environments with excessive heavy metal contamination. The diversity of true mangrove species and their associates in San Vicente River, Candelaria, Zambales, Philippines was determined. With respect to the physico-chemical composition of the water and sediments. Twenty species of true mangroves were recorded belonging to 11 different families indicating moderate diversity, and 11 mangrove-associated species observed from 10 families. Acanthus ebracteatus was the most abundant species, while Osbornia octodonta was the rarest, found only in Station 1 with only 2 individuals. Sediment samples showed heavy metal concentrations exceeding limits for chromium, iron, nickel and copper. The study highlights the impact of heavy metal contamination on mangrove diversity and soil health, disseminating conservation and remediation efforts for mangrove ecosystem in polluted environments.

Caught in transition: changes in brachyuran diversity following mangrove encroachment into saltmarshes at a southern distribution limit

Mangroves are expanding polewards due to global change, often encroaching into adjacent temperate saltmarshes. In both vegetated ecosystems, brachyurans are responsible for ecological processes and functions such as nutrient cycling and sediment bioturbation. South African mangroves occur at a latitudinal limit and are establishing further south due to past planting events and global change, making these ideal study systems for the effects of mangrove expansion and encroachment. Here, we investigated the effect of mangrove encroachment on brachyuran community composition at two saltmarsh sites with planted mangrove stands of different ages. Transects were laid perpendicular to each estuary where three habitat types were demarcated (mangrove, ecotone, saltmarsh). Sediment samples were collected for analyses and quadrats were used to measure pneumatophore density, saltmarsh cover, and brachyuran abundance and diversity. We found that brachyuran community structure at each site has significantly changed over seven years, with two mangrove-associated fiddler crab species, Tubuca urvillei and Paraleptuca chlorophthalmus, now recorded at the younger planted site, indicating a new southern distributional limit. Community structure was also significantly different amongst habitat types (p < 0.05) with Parasesarma catenatum dominating saltmarshes while Danielella edwardsii was more prominent in mangroves. However, community composition did not differ significantly between the two (differently aged) sites (p > 0.05). Pneumatophore density had a proportional relationship with crab abundance, diversity and richness, while saltmarsh cover had an inversely proportional relationship with crab abundance, diversity and richness. It is likely that as mangroves continue to expand into saltmarshes, more mangrove-associated species will move into saltmarshes, potentially altering ecosystem processes in this unique habitat.

Floristic diversity of mangroves and mangrove associate species of Kali River Estuary, Karwar, Karnataka, India

This study assessed the mangrove flora of the Kali River estuary, Uttara Kannada district, Karnataka. Fourteen true mangrove species belonging to eight families and 11 genera were documented from four locations: Devbagh, Mavinhole, Kalimatha Island, and Halgejoog. The mangrove species show a discontinuous distribution pattern in the Kali River estuary. The highest IVI in true mangroves was recorded for Avicennia officinalis at Devbagh, Acanthus ilicifolius at Mavinhole, Sonneratia caseolaris (after Oryza coarctata) at Kalimatha Island, and S. caseolaris (after Derris trifoliata) at Halgejoog. Of the four sites, Devbagh has the highest Shannon-Wiener diversity index, and with regard to species composition, Devbagh and Kalimatha Island are the most similar sites. Kalimatha island has the most well-preserved mangrove community.

Floral scents, specialized metabolites and stress-response activities in Heritiera fomes and Bruguiera gymnorrhiza from Sundarban mangrove ecosystem.

Floral biochemistry and stress physiology is an underexplored aspect of mangroves, which should be investigated as part of preservation and restoration efforts. A thriving true mangrove tree (Bruguiera gymnorrhiza (L.) Lamk.) and a threatened mangrove-associate species (Heritiera fomes Buch. Ham.) were studied in the Sundarban region of India for seasonal variations in floral odours, non-volatile phytochemicals, antioxidant enzyme activities, and surface water chemistry in surrounding habitat. Both species were found to exhibit significant differences in floral volatilomes, protein contents, antioxidant enzyme activities, total flavonoids, and total phenolic contents between spring and autumn blooms. The bird-pollinated flowers of B. gymnorrhiza also showed considerable seasonal differences in floral anthocyanin and proline contents, indicating vulnerability of the post-anthesis open flowers to environmental factors. Contrarily to previous findings, B. gymnorrhiza floral bouquet appeared to be enriched in various classes of volatiles - dominated by sulphurous compounds in bud stage and terpenoids in open stage. Floral anthocyanins, contributing to the striking colouration of the calyx, were found to comprise cyanidin and delphinidin derivatives. Other glycosides of cyanidin and delphinidin were detected in H. fomes flowers, contributing to visual guides to potential food rewards for pollinating insects. Floral tissue in H. fomes was found to be protected by densely overlapping layers of stellate trichomes containing sesquiterpenoids as phytoprotectants. Comparison of the two floral species suggested that H. fomes flowering is optimized to oligohaline (but not freshwater) vernal conditions; whereas B. gymnorrhiza blooms are adapted for biologically enriched (including abundant herbivores and microbial growth), mesohaline forest habitats.

Detection of a bibenzyl core scaffold in 28 common mangrove and associate species of the Indian Sundarbans: potential signature molecule for mangrove salinity stress acclimation.

Bibenzyl derivatives comprising two benzene rings are secondary plant metabolites with significant therapeutic value. To date, bibenzyl derivatives in the Plant kingdom have been primarily identified in bryophytes, orchids, and Cannabis sativa. The metabolic cost investment by plant species for the synthesis of these bioactive secondary metabolites is rationalized as a mechanism of plant defense in response to oxidative stress induced by biotic/abiotic factors. Bibenzyl derivatives are synthesized from core phenylpropanoid biosynthetic pathway offshoots in plant species. Mangrove and mangrove associate species thrive under extreme ecological niches such as a hypersaline intertidal environment through unique adaptive and acclimative characteristics, primarily involving osmotic adjustments followed by oxidative stress abatement. Several primary/secondary bioactive metabolites in mangrove species have been identified as components of salinity stress adaptation/acclimation/mitigation; however, the existence of a bibenzyl scaffold in mangrove species functioning in this context remains unknown. We here report the confirmed detection of a core bibenzyl scaffold from extensive gas chromatography-mass spectrometry and gas chromatography-flame ionization detection analyses of 28 mangrove and mangrove associate species from the Indian Sundarbans. We speculate that the common presence of this bibenzyl core molecule in 28 mangrove and associate species may be related to its synthesis via branches of the phenylpropanoid biosynthetic pathway induced under high salinity, which functions to detoxify reactive oxygen species as a protection for the maintenance of plant metabolic processes. This finding reveals a new eco-physiological functional role of bibenzyls in unique mangrove ecosystem.

Mangrove species structure at the Tuntang Estuary, Demak, Central Java

The Tuntang estuary is located in the coastal area of the Demak Regency, which has a considerable mangrove ecosystem potential. However, their persistence is degraded due to land conversion, deforestation, and climate change. Hence, to provide the basis for mangrove conservation in that area, it is essential to gain insight into the mangroves’ composition and structure. Vegetation data were obtained by using a quadratic transect survey method with plot sizes for categories of the tree (10x10 m), sapling (5x5 m), and seedling (2x2 m). The results showed that eleven true mangroves and three mangrove-associated species were found in the mangrove ecosystem of the Tuntang estuary. All true mangrove species are included in the International Union for Conservation of Nature and Natural Resources (IUCN) Red List of threatened species. The dominant species was Rhizophora mucronata, which showed the most significant important value index of each growth stage. The research area’s biodiversity and dominance index were categorized as very low, but the evenness index was relatively high. The standing structure in the reverse “J” shape is formed by the number of trees and regeneration ratios. The vulnerability to degradation level on density and dominance index parameters was low, while the diversity index parameter was classified as moderate, which displays a potential vulnerability to disturbances. This study highlights that conserving mangrove ecosystems on the coast around the Tuntang estuary is essential to defend the coastal area from abrasion and tidal flooding, which have been problems in the area for long periods.

Inventory of plants in the Mangrove Botanic Garden of Gunung Anyar and their potential as medicinal plants

Mangrove forest is located along the coastal area and regularly waterlogged because it is influenced by the tides, and has an important ecological function for life. Mangrove forest, especially in urban areas, is the most threatened and damaged ecosystem. Surabaya has a mangrove forest in the Mangrove Botanic Garden of Gunung Anyar (MBGGA) with an area of 32,761 m2 and has the potential for educational tourism. Scientific information concerning plant species in MBGGA is needed to support this potential. This study aimed to inventory the mangrove plants and their associated species in MBGGA and their potential as medicinal plants. The inventory was carried out by tracking method while information on medicinal potential was obtained through literature study. The results showed that MBGGA had 14 mangrove species and 11 mangrove-associated species. Around 18 species are included in the least concern category and one in the vulnerable category of the IUCN red list. All plant species in MBGGA also have potential as medicinal plants and almost all their parts, including leaves, fruit, bark, and roots, can be used for that purpose. This study showed that MBGGA was rich in mangrove species and their associated plants which were potential as medicine.

Establishing community-wide DNA barcode references for conserving mangrove forests in China

BackgroundMangrove ecosystems have been the focus of global attention for their crucial role in sheltering coastal communities and retarding global climate change by sequestering ‘blue carbon’. China is relatively rich in mangrove diversity, with one-third of the ca. 70 true mangrove species and a number of mangrove associate species occurring naturally along the country’s coasts. Mangrove ecosystems, however, are widely threatened by intensifying human disturbances and rising sea levels. DNA barcoding technology may help protect mangrove ecosystems by providing rapid species identification.ResultsTo investigate this potential, 898 plant specimens were collected from 33 major mangrove sites in China. Based on the morphologic diagnosis, the specimens were assigned to 72 species, including all 28 true mangrove species and all 12 mangrove associate species recorded in China. Three chloroplast DNA markers rbcL, trnH-psbA, matK, and one nuclear marker ITS2 were chosen to investigate the utility of using barcoding to identify these species. According to the criteria of barcoding gaps in genetic distance, sequence similarity, and phylogenetic monophyly, we propose that a single marker, ITS2, is sufficient to barcode the species of mangroves and their associates in China. Furthermore, rbcL or trnH-psbA can also be used to gather supplement confirming data. In using these barcodes, we revealed a very low level of genetic variation among geographic locations in the mangrove species, which is an alert to their vulnerability to climate and anthropogenic disturbances.ConclusionWe suggest using ITS2 to barcode mangrove species and terrestrial coastal plants in South China. The DNA barcode sequences we obtained would be valuable in monitoring biodiversity and the restoration of ecosystems, which are essential for mangrove conservation.

PHYTOREMEDIATION OF HEAVY METALS BY THE DOMINANT MANGROVE ASSOCIATE SPECIES OF INDIAN SUNDARBANS

The present study aims to investigate the phytoremediation potential of zinc (Zn), copper (Cu), and lead (Pb) by two dominant mangrove associate species, Suaeda maritima, and Salicornia brachiata, found in the high saline supralittoral zone of Indian Sundarbans in four stations of the Hooghly-Matla estuarine complex during the premonsoon season (May 2019). We found that concentrations of biologically available heavy metals (HMs) in the ambient soil and bioaccumulated HMs within the vegetative plant parts occurred as per the order: Sagar South > Bakkhali > Jharkhali > Bali Island. The order of biologically available and bioaccumulated HMs was Zn > Cu > Pb. Interestingly, the selected HMs display high organ-specificity for both species with the highest enrichment in roots, followed by stems and leaves. We propose that these halophytes could be used as agents of phytoremediation and their farming would be effective in the ecorestoration of this deltaic complex in context to conservative pollutants.

Multiple-stressor effects of warming and acidification on the embryonic development of an estuarine fiddler crab

Predicted effects of anthropogenic climate change on estuarine and coastal organisms are complex, and early life history stages of calcified ectotherms are amongst the most sensitive groups. Despite the importance of understanding their vulnerability, we lack information on the effects of multiple stressors on the embryonic development of estuarine and burrowing organisms, mainly mangrove-associated species. Here, we determined the combined effects of elevated temperature and decreased pH on the embryonic development of the estuarine fiddler crab Leptuca thayeri. Initially, the microhabitat (burrow) of ovigerous (egg-bearing) females was measured for temperature, pH, and salinity, which provided control values in our laboratory experiment. Embryos at the early stage of development were subjected to cross-factored treatments of predicted temperature and pH and evaluated for development rate, survivorship, and volume until their later embryonic stage. Embryo development was faster at early and later stages of development, and survivorship was lower under elevated temperature. Embryos under reduced pH showed advanced embryonic stages at their late development stage. Higher egg volume was observed in a warmer and acidified environment, and lower volume in warmer and non-acidified conditions, indicating that embryo development is synergistically affected by warming and acidification. More than 70% of embryos developed until late stages under the multiple-stressors treatment, giving insights on the effects of a warm and acidified environment on burrowing estuarine organisms and their early stages of development.

Population dynamics of a Sonneratia caseolaris stand in the Lam River estuary of Vietnam: a restoration perspective

Species composition, age distribution, and their relationship with land height from the datum line (LH) of the Sonneratia caseolaris stand, which grows in the Lam River estuary in Vietnam, were surveyed to obtain fundamental knowledge that aimed at contributing to mangrove restoration. The data gathered on the sandbar consists of three mangrove species and one mangrove associate species, with one non-mangrove species, and were divided into three communities. In terms of the age distribution of the S. caseolaris–Aegiceras corniculatum community, the tree-phase densities for both species are lower than those exhibited by younger phases. In its succession, the seedlings of S. caseolaris and A. corniculatum are primarily recruited at the mean tide level (MWL) in the early stages. Then, A. corniculatum expands to the lower tide zone primarily on mud flat bare land. For both species, full irradiance on the bare land in the low tide zone below MWL is crucial for growth, but S. caseolaris, which propagates by releasing small seeds, can barely survive in the low tide zone because its seeds are easily flushed away. In contrast, A. corniculatum, which propagates using crypto-viviparous seedlings, has a higher survival rate in the low tide zone. As a result, the LH of seedlings of A. corniculatum distribution is significantly lower than that of the distribution of S. caseolaris trees (p < 0.05). It is important to provide appropriate environmental conditions for forest restoration in order to promote succession. The findings from the current study on population dynamics related to LH and tidal conditions are expected to be applied to platforms for S. caseolaris stands and mangrove restoration.

Rehabilitation of Sandy Coastal Areas in Kuala Rompin, Pahang

After the tsunami incident that hit the coasts of several countries including Southeast Asia in December 2004, effort to protect the coastal areas has been immense. In Malaysia, a committee focusing in rehabilitation of coastal areas were established since 2007 to conduct planting and rehabilitation of coastal areas nationwide. In this study, mixed mangrove associate species namely Callophyllum inophyllum (Bintangor laut), Casuarina equisetifolia (Rhu), Syzygium grandis (Kelat jambu laut), Terminalia catappa (Ketapang) and Fagraea fragrans (Tembusu padang) were planted in Kuala Rompin, Pahang. The main objective of this study is to rehabilitate coastal areas with mixed species. Combinations of organic soil and slow-release fertilizer were applied as part of the improved fertilising technique. The initial growth and survival of saplings planted were measured and data obtained were analyzed using SPSS program. After 17 months of planting, the survival was 66% and Casuarina equisetifolia recorded the highest mean annual increment for height and diameter.

Measuring mangrove-fishery benefits in the Peam Krasaop Fishing Community, Cambodia

Whilst previous studies have applied economic value to the ecosystem services mangroves provide to fisheries, most quantitative studies in the peer reviewed literature have limited their measurements to the value provided through a single fishing sector, gear or particular target species group. It can be argued that present research into mangrove-fisheries has not yet represented the full complexity that mangrove-fisheries can encompass in terms of the wide range of people and activities that benefit from the mangrove ecosystem. The reported values of mangroves to fishing livelihoods are therefore likely to fall short of a full valuation. The study provides an all-encompassing value of mangrove benefits to fishing, purposefully investigating the value gained from mangroves through all fishing sectors, fishing activities and target species existing in the Peam Krasaop Fishing Community (PKFC), Koh Kong Province, southwest Cambodia. The ecosystem service value of mangroves for fishing to households in the PKFC was calculated using daily landings volumes collected through semi-structured interviews with fishers, scaled to approximated annual catches. Catch figures were converted to economic value, based on the local market prices given by respondents. Results suggested that the PKFC derives approximately 90% of fishing catch, and 85% of gross income, from mangrove-associated species. Fishing activities are diverse within households; they conduct between 1 and 8 different seasonal fishing activities, spread across mangrove gathering, fishing by boat and mariculture. This study provides a higher estimated proportion of mangrove-associated catches than many studies of fishing communities elsewhere. It may be the case that the PKFC does not have higher levels of mangrove dependency than other mangrove-fisheries. Rather, this study may provide a better quantification of mangrove value than has previously been achieved. Further studies along the same lines, taking a similarly holistic approach to mangrove-fishery valuation, are necessary to test this proposition.

Prominent genetic structure across native and introduced ranges of Pluchea indica, a mangrove associate, as revealed by microsatellite markers

AbstractAimsPluchea indica is a mangrove-associate species, known for its medicinal properties in its native range and being invasive in part of its introduced range. This study aimed to assess geographic distribution of genetic variation of this species across its distribution range, identify the factors influencing its genetic structure and use this information to suggest conservation and management strategies in its native and introduced ranges, respectively.MethodsWe assessed the genetic diversity and population structure of 348 individuals from 31 populations across its native (Asia) and introduced (USA) ranges for 15 nuclear microsatellite loci. The spatial pattern of genetic variation was investigated at both large and regional spatial scales with the hypothesis that geographic distance and natural geographic barriers would influence the population structure with varying levels of differentiation across spatial scales.Important FindingsWe found relatively high genetic diversity at the population level and pronounced genetic differentiation in P. indica, as compared with the genetic diversity parameters of mangroves and mangrove associates in this region. Most of the populations showed heterozygote deficiency, primarily due to inbreeding and impediment of gene flow. Analysis of population structures at large spatial scale revealed the presence of two major clusters across the species’ natural range separating populations in China from those in Indonesia, Malaysia, Singapore, Thailand, Cambodia and Philippines, and that the USA population might have been introduced from the population cluster in China. Genetic differentiation between populations was also observed at the regional scale. A large number of populations showed evidence of genetic bottleneck, thereby emphasizing the risk of local extinction. Based on these findings, our study recommends in situ conservation strategies, such as to prioritize populations for conservation actions and to maintain genetic diversity.

Recolonization of mollusc assemblages in mangrove plantations damaged by Typhoon Chan-hom in the Philippines

We investigated the effects of a catastrophic typhoon on mollusc assemblages of damaged mangrove plantations of different ages. Molluscs were sampled from infaunal, epifaunal and arboreal assemblages of mangrove stands in Lingayen Gulf, northwest Philippines, and compared with assemblages of un-impacted areas. Prior to the occurrence of the typhoon, there were clear shifts in the species diversity (H’) and composition of mollusc assemblages with stand age of mangrove forests. This was observed in species composition through the succession in dominance from pioneer to seral or putative climax species, and assemblage type (as arboreal, epifaunal and infaunal). However, severe damage to vegetation structure and sediment properties (associated with a reduction in tree density and canopy cover resulting in increased temperatures and exposure) following the typhoon resulted in an alteration of trajectory patterns in the damaged stands. There were shifts in species composition and dominant species from having mature mangrove-associated species (pre-typhoon) to an abrupt return in dominance of pioneer species (post-typhoon). The damage was more evident in older stands than in intermediate-aged stands. Furthermore, the reduced presence of molluscs (and also probably their activities, i.e. burrowing) may have contributed to the delayed recovery of mangroves. The prospects for recovery of the system to pre-typhoon levels are therefore uncertain where the re-establishment of seral or edaphic mollusc assemblages appears to be related to the recovery of vegetation and sediment conditions.

Samosa and Kachuri from Mangrove Associate Species: An Innovative Utilization of Coastal Flora

Samosa and Kachuri from Mangrove Associate Species: An Innovative Utilization of Coastal Flora

Phytochemical, Antioxidant and Antimicrobial Screening of Suaeda maritima L (Dumort) against Human Pathogens and Multiple Drug Resistant Bacteria

In this study, antimicrobial property of Suaeda maritima, a mangrove associate species collected from lower Gangetic delta complex was evaluated. The antibacterial activity of the extract against a wide spectrum of Gram-negative and Gram-positive isolates and multiple antibiotic resistant strains suggested that it may be a potential antibacterial agent to control antibiotic resistant infections. Among the different solvent fractions examined, n-hexane extract of the shoot of S. maritima L (Dumort) was found to possess highest antibacterial activity against four Gram-positive (Bacillus subtilis, Staphylococcus haemolyticus, Staphylococcus aureus, Enterococcus faecalis) and six Gram-negative (Escherichia coli, Citrobacter sp., Klebsiella pneumoniae, KPC producing K. Pneumonia, Pseudomonas sp. and Stenotrophomonas maltophila) bacteria. Fungicidal activity was noted against Saccharomyces cerevisiae. Minimum inhibitory concentration and minimum bactericidal concentration values were determined in disc diffusion and macrodilution assays. The inhibition zones ranged between 13-20 mm. GC-MS analysis of the n-hexane fraction showed the presence of various fatty acid esters and essential oils. In addition, scytalone known for its antioxidant property, campesterol and ethanone were detected. Antioxidant activity was found having an IC50 value of 52.53 mg/ml.

Genetic diversity and population structure of Myoporum bontioides (Myoporaceae) in China revealed by AFLP analysis

Mangrove forests are one of the most special forest ecosystems as a hub for marine biotope, yet they are also one of the most threatened and vulnerable ecosystems. Field investigations showed that many populations of Myoporum bontioides (Myoporaceae), a mangrove associate species recorded in southern China, southern Japan and northern Vietnam, have disappeared in China during the recent decades. For the conservation of this species and other related coastal mangrove species, we here report the genetic diversity and population structure of M. bontioides using amplified fragment length polymorphism (AFLP). The analysis produced 1557 polymorphic bands across all the 143 investigated individuals. Our results revealed a relatively high level of genetic diversity (species level: P=98.90%, He=0.233, I=0.451; population level: P=59.61%, He=0.171, I=0.265) and a high level of genetic differentiation (GST=0.238 and ΦST=0.316) in M. bontioides. No correlation was observed between genetic distances and geographic distances. A mixed mating system and limited long-distance dispersal ability may partially account for the genetic differentiation. UPGMA dendrogram, PCoA and STRUCTURE analysis revealed a distinct structure of M. bontioides populations. These findings underline that populations of M. bontioides should be preserved in situ, and the Gaoqiao and Taiwan populations should be prioritized for conservation.

Reproductive Biology of Mangrove PlantsClerodendrum inerme, Derris trifoliata, Suaeda maritima, Suaeda monoica, Suaeda nudiflora

AbstractFloral biology, sexual system, breeding system, pollinators, fruiting and seed dispersal aspects of five mangrove associate species, namely,Clerodendrum inerme,Derris trifoliata,Suaeda maritima, S. monoica, andS. nudiflorawere studied. All these species are hermaphroditic, self-compatible, and exhibit mixed breeding systems adapted for pollination by external agents.C. inermeandD. trifoliataare principally entomophilous, whileSuaedaspecies are ambophilous. The study suggests that these plant species are important constituents of mangrove forests.C. inermeandD. trifoliataare useful in stabilizing the banks of back water creeks, whileSuaedaspecies are useful to carpet the saline areas and desalinate the soils which are subsequently useful for agricultural activities.

Cheсklist of gastropod molluscs in mangroves of Khanh Hoa province, Vietnam.

Gastropod molluscs are one of the most important components of mangrove ecosystem. Mangroves in Central Vietnam have a rather limited distribution due to peculiarities of the coastline morphology and presently their fauna remains understudied. Extensive surveys were conducted in both natural vegetation and artificial mangrove plantations in several localities in Nha Trang Bay from 2005 to 2015. In total 65 species of gastropod molluscs were found alive, 17 of which can be considered as predominantly mangrove-associated. An illustrated guide is provided, with short synonymies and data on ecology and distribution. The recorded molluscan diversity is compared with published data on mangrove gastropods in different regions of the Indo-Pacific. Total species number and the proportion of mangrove-associated species are similar to studied faunas in Hong Kong, Malaysia and Thailand, but the diversity is much lower than that of the mangal fauna of the Philippines.