Coastal Mangrove Research Articles

Wood in Pre-Columbian Funerary Rituals: A Case Study from El Caño (Panama, AD 880–1020)

ABSTRACT This research presents for the first time a comprehensive study of charcoal directly related to the multiple burials interred in Tomb 2 of El Caño (Coclé province, Panama). This funerary context, which dates to between AD 880 to AD 1020, contained three different burial levels accompanied by substantial ceramic offerings and rich mortuary assemblages. The challenge of taxonomically identifying charcoal from tropical areas was addressed by combining standard procedures in tandem with chemical analysis (Py-GC-MS) of archaeological charcoal and fresh wood from the reference collection. Nine charcoal types were identified at the genus level: Avicennia spp., Rhizophora spp., Handranthus/Tabebuia, cf. Copaifera spp., Inga spp., Guettarda spp., Roupala spp., Allophylus spp. and cf. Ryania spp. Charcoal of cf. Copaifera spp., Roupala spp., Guettarda spp., and probably Handroanthus/Tabebuia might be related to their use as firewood for producing smoke. The presence of Copaifera and Roupala indicates the selection of odorous woods for burning in the sahumerios. Diverse habitats, such as coastal mangroves, riverine and dry forests, were exploited to obtain wood, highlighting the complex management of wild plant resources developed by the hierarchical societies of the Isthmo-Colombian area.

Topography, drainage capability, and legacy of drought differentiate tropical ecosystem response to and recovery from major hurricanes

High-carbon sequestrations of tropical montane forests and coastal mangroves have been greatly disturbed by intensified extreme climate events such as alternating hurricanes and droughts. However, few studies of the hurricane impact have taken into consideration the legacy of past climate events and analyzed the heterogeneity of hurricane impacts between montane forests and coastal mangroves. Here, we studied the impact of Hurricanes Irma and Maria in 2017 on coastal mangroves and upland forests in Puerto Rico after a severe drought during 2015–2016. We investigated the island-wide immediate impact on greenness using fused vegetation index from Sentinel-2 and Landsat-8, and the impact on and the recovery of 62 homogeneous vegetation patches by deriving an impact index and one-year recovery ratio (RR). A linear mixed-effect model was applied to explore roles of hurricane wind, rainfall, topography, and biological components in the impact and the recovery. Island-wide, the immediate impact is highly spatial-heterogeneous. Although most of the island was browned, a green-up strip in the dry south showed benefits from the hurricane rain which relieved the prior drought stress. Coastal mangroves experienced the greatest impact and slowest recovery with relative recovery of 0.44 compared to recovery greater than 0.70 for upland forests, and evergreen forests sustained significantly more damage than deciduous forests. The recovery of evergreen forests was on average 11 days earlier and faster than that of mangroves. Mangrove recovery was mostly limited by inundation-related factors such as elevation, slope, and drainage capacity. While higher elevation relates to slower recovery for upland forests, it favors mangrove recovery. Particularly, mangrove recovery is facilitated by river presence, explaining 65% variation in RR. The differentiated response, recovery, and underlying mechanisms highlighted a complicated array of external forces, geophysical/ biological modulators, and legacy of past climate events in determining and understanding hurricanes’ impact on tropical ecosystems.

On the reappearance of the Indian grey wolf in Bangladesh after 70 years: what do we know?

The Indian grey wolf, Canis lupus pallipes Sykes, 1831, is a small, cryptic subspecies and the only wolf living in arid plains and deserts of the Indian subcontinent. Since 1950, it has been considered extinct beyond 88° east longitude. Herein, we report an instance from Bangladesh after 70 years. A solitary male of C. l. pallipes was killed in retaliation in June 2019 as livestock predation events erupted and lasted for a month after a severe cyclone had swept coastal Bangladesh. The specimen was about 119 cm from nose to tail tip with a skull length of 26.23 cm. Two molecular markers, mt d-loop control region and 16S rRNA, and 54 cranial parameters consolidated the identity. Bayesian inference and maximum-likelihood analyses indicated its intraspecies position. The locality of conflict, 450 km eastward of the easternmost population of C. l. pallipes, is adjacent to the Sundarbans in the Ganges estuary that presents formidable tidal rivers as dispersal barriers. In 2017, another wolf was sighted from the Indian Sundarbans vicinity. The present incident and the sighting of 2017 remarkably appeared from the farthest corners of a 10,000 km2 strong mangrove network that is rimmed by dense human settlements. The records surmise about the most challenging wolf dispersal route ever recorded. Additionally, the south-central coasts of Bangladesh, once home to wolves, bear old planted mangroves with open dunes but never surveyed for mammals. These facts necessitate a systematic camera-trapping in the coastal mangroves of Bangladesh exclusively intended for wolves.

Contemporary distribution of benthic foraminiferal assemblages in coastal wetlands of south-eastern Australia

Benthic foraminifera identified from the upper intertidal zone of coastal mangrove and saltmarsh wetlands of south-eastern Australia exhibit spatial zonation that varies with elevation and corresponds to position in the tidal frame. This study describes relationships between benthic foraminiferal assemblages and environmental variables, such as wetland elevation, pore-water salinity, substrate organic matter content and sediment grainsize. Agglutinated taxa dominated higher in the tidal frame, whereas calcareous taxa increased in both relative abundance and diversity lower in the tidal frame. Species composition varied within and between study sites, reflecting local differences in other environmental variables. Three major spatial clusters were identified in the upper intertidal zone from a dataset consisting of 111 contemporary samples: a high-to mid-elevation assemblage consisting of differing abundances of Entzia macrescens and Trochammina inflata; a mid-elevation assemblage comprised of Arenoparrella mexicana in association with Trochammina inflata and Quinqueloculina seminula; and mid-to low-elevation assemblage characterised by Cribroelphidium excavatum, Quinqueloculina seminula, Ammobaculites spp. and Miliammina fusca. Multivariate analysis correlated foraminiferal assemblages with environmental variables showing that foraminiferal distribution in the region is constrained primarily by wetland elevation, but also by pore-water salinity. Foraminiferal assemblages derived from cluster analysis correlated with vegetation zones, implying that both foraminifera and vegetation are influenced by elevation and salinity. This paper seeks to demonstrate that the consistency in spatial zonation of assemblages provides greater confidence that contemporary distribution of foraminiferal assemblages can assist with the interpretation of past depositional conditions and palaeo-environmental reconstructions, providing insights into the evolution of coastal wetlands of south-eastern Australia over the Holocene.

Salinity and rainfall as inducers of cell proliferation and apoptosis in mangrove oyster Crassostrea gasar spermatogenesis

The present study investigated the influence of physical–chemical​ variables on the development of male gonads, providing information on cell proliferation and apoptosis in cells of the spermatogenic lineage throughout the reproductive cycle. Seeds of oysters of the species Crassostrea gasar from the same population were grown in two cultivation areas with different seawater influences. The area I, located in the municipality of Nova Olinda and area II, in the municipality of Curuçá. The two areas are part of the mangrove coast of the Amazon region and are located approximately 5 and 25 km away from the Atlantic Ocean, respectively. A sample containing 20 specimens of oysters was collected monthly in each of the two areas, and the abiotic parameters were also measured in situ during the collections. Routine histological techniques were used for cell characterization, as well as the classification of gonadal stages and morphometric measurements. Immunohistochemistry was used to access cell proliferation and apoptosis. The abiotic parameters varied constantly during the study, however, precipitation and salinity were the variables that most differed between periods in both areas. The cells of the spermatogenic lineage of C. gasar did not differ from the morphological point of view, however, the analysis of the morphometric parameters showed significant differences both in the cell diameters between maturation periods and between the study areas. Proliferative and apoptotic activities also varied throughout the study, and the quantification of positively labeled cells showed statistically significant differences between the study areas. The animals in the area I showed greater proliferative activity in relation to individuals in area II and using a regression model, we demonstrated that both cell proliferation and apoptosis are related to environmental conditions. It seems likely that animals in area I, exposed to a salinity of ∼25–35, find more favorable environmental conditions for their reproduction since the reduction in cell proliferation observed in area II was negatively related to the salinity of this environment (∼15– 25). Changes in the dynamics of mangrove interstitial waters contribute to changes in the salinity of the environment and can directly impact the physiology of oysters. These findings indicate that oyster farming systems in estuarine environments should be in areas as close to the ocean as possible.

Using nexus thinking to identify opportunities for mangrove management in the Klang Islands, Malaysia

Despite wide recognition of the multiple ecosystem services provided by mangroves, they continue to experience decline and degradation especially in the face of urbanization. Given the interplay between multiple resources and stakeholders in the fate of mangroves, mangrove management can be framed as a nexus challenge and nexus thinking used to identify potential solutions. Using the Klang Islands, Malaysia, as a case study site, this paper characterizes the mangrove nexus and stakeholders' visions for the future to identify potential options for future management. Through a series of stakeholder workshops and focus group discussions conducted over two years, results show that local communities can identify benefits from mangroves beyond the provisioning of goods and significant impacts to their lives from mangrove loss. While better protected and managed mangroves remained a central part of participants' visions for the islands, participants foresaw a limited future for fishing around the islands, preferring instead alternative livelihood opportunities such as eco-tourism. The network of influencers of the Klang Islands’ mangroves extends far beyond the local communities and many of these actors were part of the visions put forward. Stakeholders with a high interest in the mangroves typically have a low influence over their management and many high influence stakeholders (e.g. private sector actors) were missing from the engagement. Future nexus action should focus on integrating stakeholders and include deliberate and concerted engagement with high influence stakeholders while at the same time ensuring a platform for high interest/low influence groups. Fortifying existing plans to include mangroves more explicitly will also be essential. Lessons learnt from this study are highly relevant for coastal mangrove systems elsewhere in the Southeast Asian region.

Experimental Assessment of the Flow Resistance of Coastal Wooden Fences

Wooden fences are applied as a nature-based solution to support mangrove restoration along mangrove coasts in general and the Mekong Delta coast in particular. The simple structure uses vertical bamboo poles as a frame to store horizontal bamboo and tree branches (brushwood). Fence resistance is quantitatively determined by the drag coefficient exerted by the fence material on the flow; however, the behaviour of drag is predictable only when the arrangement of the cylinders is homogeneous. Therefore, for more arbitrary arrangements, the Darcy–Forchheimer equations need to be considered. In this study, the law of fluid flow was applied by forcing a constant flow of water through the fence material and measuring the loss of hydraulic pressure over a fence thickness. Fences, mainly using bamboo sticks, were installed with model-scale and full-scale diameters applying two main arrangements, inhomogeneous and staggered. Our empirical findings led to several conclusions. The bulk drag coefficient ( C D ¯ ) is influenced by the flow regime represented by Reynolds number. The drag coefficient decreases with the increase of the porosity, which strongly depends on fence arrangements. Finally, the Forchheimer coefficients can be linked to the drag coefficient through a related porosity parameter at high turbulent conditions. The staggered arrangement is well-predicted by the Ergun-relations for the Darcy–Forchheimer coefficients when an inhomogeneous arrangement with equal porosity and diameter leads to a large drag and flow resistance.

Anoxygenic phototroph pufLM gene sequences derived from tropical aquatic sampling sites: Diversity, distribution, and phylogenetics

Purple sulfur bacteria (PSB) and purple non-sulfur bacteria (PNSB) are characterized by their ability to perform anoxygenic photosynthesis. PSB and PNSB are ubiquitously found in coastal waters, enclosed lagoons, stagnant water, mangrove soils, estuaries, and similar environments. In this study, we examine microbial diversity in PSB enrichments derived from a variety of tropical sampling sites (e.g., Thailand, Puerto Rico) associated with shrimp ponds, coastal mangroves, fresh water ponds, and Nymphaeaceae (i.e., water lily) plant tissue. Since 16S rRNA-based analyses are inadequate to describe the diversity of phototrophic bacteria, other biomarkers (e.g., pufLM) are used to construct phylogenies and elucidate biogeography. Our samples indicate that the majority of sequences associated with freshwater pond PSB were related to known marine, halophilic, or salt-tolerant PSB (e.g., Marichromatium, Allochromatium, Thiococcus, and Thiohalocapsa). Phylotypes not closely-associated with known species of PSB (or PNSB) were also found. PNSB gene sequences, which appear to be related to Rhodopseudomonas and Rhodoplanes, were mostly found in freshwater samples and from Nymphaeaceae plant tissues, suggesting a difference in the ecology and distribution of these two broader bacterial groups. This difference is likely due to differences in habitat such as physical (e.g., temperature) and chemical parameters (e.g., salinity). Our preliminary analyses demonstrate a rich diversity of anoxygenic phototrophic bacteria from tropical sampling sites. Few studies have described the diversity of purple bacteria in tropical environments using full pufLM gene sequences. Employing next-generation sequencing (NGS) appears to provide greater resolution towards a deeper understanding of the global diversity and distribution of these anoxygenic phototrophs.

Modeling and Prediction of Water Quality: Evidence of Benarpota Station of Sundarbans Region

The Sundarbans contain the world's largest coastal mangrove forest, with an area of about 10,000 km2 (3,900 sq mi), of which about 6,000 km2 (2,300 sq mi) are located in Bangladesh and about 4,000 km2 (1,500 sq mi) in India. Salinity will be the major issue in the future which could destroy the natural ecological balance. The major salinity components are electric conductivity (EC) at low tide and high tide with the corresponding chloride in low tide and high tide. This study develops a SARMA (2, 0, 2) (2, 0, 0) [4] model as it provides the minimum value of model selection criterion (AIC, BIC, SIC, RMSE) compare to all other models. It was found that the bestfitted model for EC in a high tide of study area follows a seasonal autoregressive moving average model of order (2, 0, 2)(2, 0, 0) [4] and chloride in high tide follows SARMA (1, 0, 1) (2, 0, 2) [4]. After fitting the time series model and forecasting the fitted model, the study showed that in both electric conductivity (EC) and salinity (Chloride ppm) increasing in the last three decades. EC crosses the poor water quality level which is more than 4 ppt or 2560 ppm. Salinity also crosses the poor water quality level which is more than 5 ppt or 3200 ppm. The findings of this study would be a potential contribution to make a comprehensive management plan for the long-term conservation and protection of the cultural landscape and mangrove wetlands ecosystem in the Sundarbans region.

Blue carbon from the past forecasts the future.

Coastal mangrove ecosystems must rise above sea level to survive

Vegetation Structure and Potential of Blue Carbon based on Hydromorphic Degraded Mangrove in the Northern Manokwari, West Papua

The mangrove forest in northern West Papua Province has important roles in both economic and ecological interests. This forest is facing various pressures so it is now degraded. The objective of this study was to ascertain the vegetation structure and potential for the blue carbon reserves. The bio-physical characteristic data were collected by establishing sampling plots at 2 locations representing coastal and estuarine mangrove forest. The results showed that the species diversity index in Saubeba Bay (estuarine mangrove) was low (H’= 1.26), while, the species diversity index in Saukori Bay (coastal mangrove) was very low (H’= 0.66). In Saubeba Bay,Bruguiera cyclindrica and Avicenialanatahad the largest IVI, namely 87.47% and 80.55% respectively, while in Bay SaukoriAegiceras floridumhad the highest IVI (139.01%). The total carbon stocks of AGB and BGB of mangrove forest in Saubeba Bay were 224,77 MgC/ha and 77,57 MgC/ha respectively, while those in Saukori Baywere 174,90 MgC/ha and 59,98 MgC/ha, respectively.

Monitoring Changes in Coastal Mangrove Extents Using Multi-Temporal Satellite Data in Selected Communes, Hai Phong City, Vietnam

Mangrove forests are important and known as one of the most productive ecosystems in the tropics. They reduce the impacts of extreme events, provide important breeding grounds for aquatic species and build the resilience of ecosystem-dependent coastal communities. On the contrary, they are also known as one of the most threatened and vulnerable ecosystems worldwide, which have experienced a dramatic decline due to extensive coastal development during the last half-century. Remote sensing techniques have demonstrated a high potential to detect, identify, map, and monitor mangrove conditions and its changes, which is reflected by a large number of scientific papers published on this topic. The aim of this study was to investigate the multi-decadal changes of mangrove forests selected communes in Hai Phong city, North Vietnam, based on using Landsat and Sentinel 2 data from 2000 to 2018. The study used these continuous steps: 1) data pre-processing; 2) image classification using Normalized Difference Vegetation Index; 3) accuracy assessments; and 4) multi-temporal change detection and spatial analysis of mangrove forests. The classification maps in comparison with the ground reference data showed the satisfactory agreement with the overall accuracy was higher than 80.0%. From 2000 to 2018, the areas of mangrove forests in the study regions increased by 584.2 ha in Dai Hop and Bang La communes (Region 1) and by 124.2 ha in Tan Thanh, Ngoc Xuyen and Ngoc Hai communes (Region 2), mainly due to the boom of mangrove planting projects and good mangrove management at the local community level.

Mangrove benthic macrofauna: drivers of community structure and functional traits at multiple spatial scales

Environmental processes acting at multiple spatial scales influence the structure and function of macrofaunal communities in marine habitats. However, the relative contributions of small- and large-scale factors in shaping faunal communities are still poorly understood. We investigated the relative contributions of climate, geophysical and soil properties, and forest structure on structural and functional characteristics of Brazilian coastal mangrove macrofauna. We found that macrofaunal community structure is mainly driven by large-scale factors, such as minimum air temperature and runoff, which significantly differed among the coastal settings investigated. Conversely, annelid assemblage functional traits were correlated with small-scale factors such as aboveground biomass, subsurface root biomass, soil bulk density, and soil phosphorus. Annelids with diversified and more complex functional traits (e.g. with respect to appendages, segments, parapodia) preferentially inhabited sites with low subsurface root biomass, while annelids with a slender body plan were more common at sites with dense root mats. Thus, while climate and geophysical conditions drive benthic macrofaunal community structure at larger spatial scales (i.e. coastal setting) in this system, vegetation and soil factors at smaller spatial scales (i.e. site) were more related to annelid functional characteristics.

Anthropogenic Drivers of Relative Sea-Level Rise in the Mekong Delta – A Review

AbstractThe Mekong Delta is sinking and shrinking. This is because of the absolute sea-level rise, and because of the subsidence of the land. The absolute sea-level rise originates from the thermal expansion of the ocean waters and the melting of ice on land, plus other factors including changes in winds and ocean circulation patterns. The subsidence originates from the construction of dams in the river basin upstream of the Delta, that has dramatically reduced the flow of water and sediments, and excessive groundwater withdrawal, plus other factors including riverbed mining, infrastructural extension, and urbanization. The origin of alluvial delta created by a continuous supply of water and sediments and the natural subsidence of uncompacted soils is relevant background information to understand the current trends. Another factor affecting the sinking and shrinking include the degradation of the coastal mangrove belt. It is concluded that the subsidence due to the reduced flow of sediments and water, and the withdrawal of groundwater more than the replenishment of aquifers is more than one order of magnitude larger than the absolute sea-level rise estimated by satellite and climate models, or the value estimated from tide gauges, that is much less. The current sinking and shrinking trends are not sustainable, as the low-lying Delta may disappear before the end of this century.

Implications on food production of the changing water cycle in the Vietnamese Mekong Delta

The Mekong Delta is sinking and shrinking due to excessive groundwater withdrawal for growing agricultural and other uses, coupled to reduced flow of water and sediments caused by upstream dams, growing upstream water uses and riverbed mining, reduced replenishment of aquifers, soil compaction, infrastructural extension, and thermo-steric sea level rise. Salinization of soil and aquifers, depletion of aquifers, constraints to fish migration, increased pollution, reduced flow of nutrients, deterioration of the coastal mangrove belt, general degradation of the ecosystem, and loss of emerged land, make the production of food from agriculture and fisheries more difficult, while also limiting the availability of clean fresh water for domestic uses. The subsidence generated by excessive groundwater withdrawal is more than one order of magnitude larger than the thermo-steric sea level rise. Particularly relevant is also the effect of the reduced flow of water, and sediments caused by upstream dams and growing upstream water uses. These drivers are changing the low-lying Mekong Delta, with dramatic impacts on food security expected by as early as 2050, and the possible complete disappearance of the Mekong delta as we know by 2100. While technological developments and enforcement of mitigation and adaptation strategies expected to overcome the most part of the short term issues, with production from aquaculture actually expected to dramatically rise to 2050, but contemporary reduced growth, if not reduction in the agricultural output, these measures may not be enough by 2100. The current rates of development, in both economy and population, are, not sustainable.

Assessment of the vulnerability of coastal mangrove ecosystems in Mozambique

Mangrove forests are among the most productive ecosystems on Earth. However, there is still insufficient information available for strategic prediction of conservation and management intervention, particularly in the case of Mozambique. This country has the longest coastline and mangrove forests of Eastern Africa, but is prone to global climate hazards. Using recent field data and environmental parameters subjected to the Variance Inflation Factor (VIF) collinearity test (bioclimatic variables, slop, salinity, land cover, and elevation), we ran MaxEnt to model the distribution of mangrove forests based on occurrence data of the most emblematic and representative mangrove species in Mozambique (Avicennia marina and Rhizophora mucronata). Moreover, in order to understand which areas should be prioritized for management interventions on mangroves and costal dunes, an Exposure Index (EI) to climate hazards and erosion was compared with the potential distribution of these species. Our results showed that average wind speed of summer season, land surface elevation, Mean Diurnal Range, and saltwater exposure (salinity) were determinant on the distribution models of both species. The central coastal region of Mozambique (so-called swamp coast) presents the largest potentially suitable areas for mangroves species occurrence, having the highest levels of exposure. We also found that A. marina presents a higher EI than R. mucronata. The scarcity of studies concerning the central region of Mozambique; which was recently devastated by cyclone Idai (category four, 2019), which hit Mozambique and the neighbouring countries, reinforce the urgency for management intervention. The findings of this study should be used by managers and decision makers to promote best practices to safeguard lives and people's livelihoods and assets threatened by coastal climate hazards and anthropogenic impacts.

Biogeographic pattern of the nirS gene-targeted anammox bacterial community and composition in the northern South China Sea and a coastal Mai Po mangrove wetland.

Functional genes, namely hzo/hao, nirS, hzs, and ccs gene, are efficient with high specificity for detecting anammox bacteria. Sc-nirS and An-nirS primer sets were proposed for targeting Scalindua/non-Scalindua anammox bacterial groups; previously, they have not been assessed for biogeographic study on marine-terrestrial transitional systems, specifically marine and terrestrial ecosystems. Here, we report phylogenetic distribution pattern of anammox bacteria in both northern South China Sea (nSCS) and Mai Po wetland (a coastal mangrove) using nirS gene-based primers. A well-delineated biogeographic distribution pattern from ocean to continental shelf was evident by combining both gene-based analyses as previously depicted using 16S rRNA as the biomarker. Furthermore, factors affecting the abundance and composition of An-nirS genes in Mai Po wetland were identified as substrate (NO3-/NO2- concentration) and anoxic/oxic condition in association to depth. An-nirS gene abundance was from 2.6 × 103 to 1.2-1.4 × 104 copies/g dry sediment in nSCS; and it was around 5 × 103 and 1-2 × 104 copies/g dry sediment in surface and subsurface sediments of Mai Po wetland, respectively. In addition, nirS gene abundance and distribution pattern of denitrifiers and anammox bacteria in the wetland indicates a competition relationship between them. Mangrove vegetation affected the community composition of An-nirS gene considerably, and a more homogeneous distribution pattern was observed in the mangrove forest than intertidal mudflats. Sc/An-nirS gene-based biogeographic insights on anammox bacteria have shed lights on the compositional and potential functional dynamics and emphasized the importance of molecular tools on refining the current microbial ecological patterns.

The Effect of Vegetation on Surface Elevation in Coastal Mangrove Areas

Guo, Y.; Chen, Y.; Liao, B.; Huang, B.; Wu, F., and Jiang, Z., 2020. The effect of vegetation on surface elevation in coastal mangrove areas. Journal of Coastal Research, 36(3), 600–607. Coconut Creek (Florida), ISSN 0749-0208.Rising sea levels pose a serious threat to global coastal mangroves. The ability of surface elevation to change synchronously with rising sea level is the key to the survival of mangroves. Mangrove vegetation can have a variety of effects on surface and subsurface processes; therefore, it has an important role in surface elevation changes. In this study, rod surface elevation table–marker horizon (RSET-MH) technology was used to study changes in surface elevation and accretion between nonvegetated and vegetated mangrove areas at three different sites. The results showed that the existence of vegetation had a significant effect on elevation changes, with increased surface elevation in vegetation areas observed to be significantly greater than those in nonvegetation areas. In addition, the subsurface changes in vegetated area showed expansion, whereas the nonvegetation area showed subsidence. Surface accretion showed variable trends in different research sites, although these could be related to their geographical location and thus be affected by many factors. Moreover, there was a significant correlation between density of vegetation and elevation/subsurface changes (r = 0.763, p < 0.05; r = 0.714, p < 0.05 respectively), and there were no significant correlations between accretion and vegetation characteristics. The results indicate that mangrove vegetation has a positive effect on the increase of surface elevation, and vegetation density may be a key factor because of the high biomass and carbon storage rate in high-density areas. This study provides additional data with which to explore the elevation variation in mangroves and a scientific basis and technical support for strengthening wetland protection.

Coastal Mangrove Response to Marine Erosion: Evaluating the Impacts of Spatial Distribution and Vegetation Growth in Bangkok Bay from 1987 to 2017

Long time-series monitoring of mangroves to marine erosion in the Bay of Bangkok, using Landsat data from 1987 to 2017, shows responses including landward retreat and seaward extension. Quantitative assessment of these responses with respect to spatial distribution and vegetation growth shows differing relationships depending on mangrove growth stage. Using transects perpendicular to the shoreline, we calculated the cross-shore mangrove extent (width) to represent spatial distribution, and the normalized difference vegetation index (NDVI) was used to represent vegetation growth. Correlations were then compared between mangrove seaside changes and the two parameters—mangrove width and NDVI—at yearly and 10-year scales. Both spatial distribution and vegetation growth display positive impacts on mangrove ecosystem stability: At early growth stages, mangrove stability is positively related to spatial distribution, whereas at mature growth the impact of vegetation growth is greater. Thus, we conclude that at early growth stages, planting width and area are more critical for stability, whereas for mature mangroves, management activities should focus on sustaining vegetation health and density. This study provides new rapid insights into monitoring and managing mangroves, based on analyses of parameters from historical satellite-derived information, which succinctly capture the net effect of complex environmental and human disturbances.

Habitat Characterization of Juvenile Atlantic Tarpon (Megalops atlanticus) in Isle of Youth, Cuba

Tarpon is considered a ‘Vulnerable’ species by IUCN but is also a highly prized recreational species. It is reportedly abundant in Cuba and may be threatened by high levels of fishing pressure. However, the current knowledge about Tarpon habitat characteristics and ecology in Cuba is very poor, which limit any attempt for its management and conservation. Here we summarize abiotic characteristics of juvenile Tarpon habitats in Lanier Swamp, Isle of Youth, Cuba, which is a RAMSAR site and Faunal Refuge. Three locations in Lanier Swamp were sampled for juvenile Tarpon presence during 2015-2017: Colony Lagoon (CL), Punta Francés Lagoon (PFL) and San Pedro (SP) river system. Abiotic characteristics were sampled from these same sites in January 2017. The smallest Tarpon (~150 mm fork length (FL, n= 22) occurred at CL, characterized by shallower waters with extreme salinities (0.6 and 50.8), less connection with the sea, and more protection from sunlight. In contrast, larger juvenile Tarpon (~630 mm FL, n= 20) were captured at SP, the location with the greatest connectivity to the ocean and greatest depth (~353 cm). The main results suggest that water depth, salinity, sunlight exposure and spatial dimensions are important habitat characteristics. Additionally, this study demonstrates the importance of coastal mangroves as juvenile Tarpon habitat and highlights the potential of using Tarpon as an umbrella species with broader conservation benefits. This study is an important first step to understanding Tarpon habitat use patterns in Cuba and developing a comprehensive conservation plan.