Search Results (280)

The role of mangrove root exudates in mediating the nitrogen cycle, particularly under high dissolved inorganic nitrogen (DIN) input, in coastal ecosystems remains unclear. This research investigated variation in the root exudates, and nitrogen transformation and output, in constructed mangrove wetlands planted with Kandelia obovata under high, moderate, and low nitrogen-input levels (PCWs-H, PCWs-M, and PCWs-L, respectively). PCWs-H promoted increased root density and biomass accumulation, enhancing soil nitrogen sequestration, whereas PCWs-L induced greater specific root length, specific root surface area, and number of root tips. These changes directly influenced denitrification efficiency. Hydroxymethoxyphenylcarboxylic acid-O-sulfate and Arg-Ser released in root exudates under PCWs-H might act as potential denitrification inhibitors, thereby suppressing denitrifiers and impairing dissolved nitrogen purification. Elevated nitrogen loading predominantly limited denitrification, resulting in relative NO₃⁻-N removal rates of PCWs-H < PCWs-M < PCWs-L (p < 0.05). Compared with PCWs-H and PCWs-L, the enhanced soil organic nitrogen storage under PCWs-M was associated with flavonoids in root exudates. Metagenomic analysis showed that denitrification was the dominant nitrogen removal pathway. Nitrogen loading influenced the effects of root exudates on the microbial community. Under PCWs-H, triterpenoids promoted norBC and nirK/S abundance but depressed amoABC abundance. Sterols and flavonoids in exudates under PCWs-L depressed nosZ abundance, instead activating dissimilatory nitrate reduction to ammonium. Compared with PCWs-H and PCWs-L, N₂O emissions were minimal under PCWs-M. This study revealed that mangrove root exudates mediate the nitrogen cycle in mangrove wetlands, providing a theoretical basis for local authorities to manage DIN inputs and mitigate N₂O emissions. Full article

As coastal communities face escalating climate risks driven by climate change and biodiversity loss, integrating mangrove ecosystems into sustainability-oriented governance frameworks spanning ecological conservation, climate adaptation, and natural capital accounting has become a global priority. However, quantifying their protection values based on spatiotemporal shoreline dynamics under extreme disturbance remains challenging. Focusing on Dongzhai Harbor (China), this study integrates multi-temporal remote sensing (2010–2021), shoreline evolution analysis, and the Replacement Cost Method to assess ecosystem resilience against Super Typhoon Rammasun in 2014. Results show mangroves exhibited substantial post-disturbance resilience, with only 6.10% area loss following Typhoon Rammasun and 46% natural recovery within six years. Bootstrap confidence intervals for the mangrove-shoreline association overlapped zero across all three temporal periods, indicating that the observational data do not support a statistically confirmed causal protection effect at the landscape scale. This finding underscores that spatially co-occurring ecosystem services do not automatically imply causation, reinforcing the need for empirically grounded valuation in sustainable land-use planning. Because mangroves naturally establish in sheltered environments, the observed spatial overlap between mangroves and the shoreline cannot be interpreted as direct evidence of causal shoreline stabilization. Based on this framework, the potential protection value reached 907.65 × 10⁴ CNY yr⁻¹ across 32.57 km of weighted coastline aligned with mangroves. Notably, erosional segments contributed 50.5% of this value despite comprising only 27.3% of the length, indicating that the replacement-cost estimate is concentrated in erosional segments under the assumed parameters. While acknowledging the need for local biophysical validation and uncertainty analysis in scaling, these findings support integrating dynamic nature-based solutions into territorial planning and Gross Ecosystem Product accounting. The resulting valuation framework offers a replicable pathway for advancing multi-dimensional sustainability encompassing climate-adaptive coastal governance, natural capital integration, and evidence-based coastal spatial planning. Full article

Due to multiple anthropogenic drivers, coastal wetlands have lost roughly 50% of their historical coverage, and deterioration is accelerating with rising sea levels. Thin-layer placement (TLP), the spreading of sediment dredged from nearby water bodies across existing wetlands or shallow mudflats to raise surface elevation, has emerged as a viable approach to sustain and restore these habitats. Strategies for the prioritization of site selection and design elements for TLP interventions remain unclear; a gap that must be closed to coordinate dredging with wetland restoration efficiently, given time, financial, and sediment constraints. Here, we present a transferable workflow to plan TLP projects, including systematic assessment of restoration needs, development of sediment application options, and prioritization of project sites that leverage publicly available remote-sensing data products and stakeholder input. We demonstrate its applicability in a rapidly deteriorating salt marsh–mangrove co-dominated system on the Atlantic coast of Florida. Guided by stakeholder priorities for storm-surge mitigation and habitat improvement, we tracked long-term (1952–2023) changes in vegetated wetland coverage to quantify loss trends and establish historic habitat borders as restoration targets. We then summarized short-term (2010–2023) habitat-mosaic shifts to resolve plant-species composition changes. In our focal system, long-term analyses revealed hotspots (zones 1 and 7) of >35% vegetation loss, while short-term analyses showed a 180% mangrove expansion and cordgrass degradation across all zones, suggesting a nuanced, tailored approach to sediment application. Taken together, this workflow provides a data-driven, stakeholder-informed process for TLP site prioritization to restore threatened wetlands, bolster coastal resilience, and maximize stakeholder benefits in our demonstration system in northeast Florida and, more broadly, to other dynamic coastlines. Full article

In Luoyuan Bay, China, Sporobolus alterniflorus invasion has hindered mangrove restoration and disrupted faunal communities within mangrove habitats. This study investigated its impact on mollusk, crab, and fish assemblages across mangrove, mudflat, and invaded habitats from 2019 to 2020. Results showed that species diversity of three assemblages did not differ significantly between invaded and non-invaded mangrove habitats; however, assemblage structure was altered and functional traits declined markedly in invaded areas. Compared with non-invaded mangroves, invaded habitats showed decreases of 81.6% in mollusk density, 50.7% in mollusk biomass, 66.6% in crab density and 84.2% in crab biomass. Dominant fish species (Acanthogobius ommaturus, Liza carinata, Stolephorus chinensis) also exhibited lower body size, total size and biomass in invaded habitats. Given the close dependence of coastal residents on these faunal resources, a socioeconomic analysis of livelihood strategies was conducted, revealing Sinonovacula constricta aquaculture achieved the highest net income-to-investment ratio, 122.7% higher than nearshore fishery and 308.3% higher than shallow-sea oyster cultivation, while professional shellfish farming yielded the highest net income per hectare, 23.6% higher than oyster cultivation. Thus, both forms of shellfish aquaculture provide greater economic returns than other livelihood options. Based on these findings and niche theory, we propose a management framework: after removing S. alterniflorus, plant native mangroves (Kandelia obovata) in mid-to-high intertidal zones and lease lower flats for shellfish farming. This framework has the potential to integrate ecological restoration with local livelihoods and may inform similar efforts in other regions facing biological invasions and restoration challenges. Full article

Mangrove ecosystems in coastal wetland restoration areas are experiencing escalating nitrogen stress, yet the microbial metabolic mechanisms underlying soil carbon sequestration in Kandelia obovata systems under exogenous nitrogen input remain unclear. In this laboratory tidal simulation experiment, five nitrogen addition levels (N0–N4) were applied to two treatments, namely the planted group and the unplanted group. Results showed that total carbon (TC), microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN) were all higher under nitrogen addition than in the N0 control. TC showed a unimodal response to nitrogen addition, with the highest values observed at N2, while the planted group exhibited the greatest relative increase in TC over the unplanted group at N3 (53.49%). MBC and MBN contents initially increased and then decreased with elevated nitrogen addition, peaking at the N3 treatment. Compared with the N0 control, MBC and MBN contents under N3 increased by 31.83% and 206.24% in the planted group, and by 23.46% and 279.03% in the unplanted group, respectively. Microbial carbon source utilization was stronger in the planted group, where microorganisms preferred amino acid and lipid carbon sources. Microbial communities in the unplanted group fluctuated markedly under nitrogen input, whereas those in the planted group were more stable with higher evenness. In the planted group, nitrogen addition promoted carbon sequestration by enhancing microbial activity and biomass accumulation, while in the unplanted group, nitrogen input exerted complex effects and directly suppressed soil carbon sequestration. These findings suggest that the introduction of Kandelia obovata may enhance microbial biomass, stabilize microbial carbon-use strategies, and promote short-term soil carbon accumulation under moderate nitrogen addition in a laboratory tidal simulation system. Overall, the N3 treatment (20 g N m⁻² a⁻¹) serves as a key nitrogen threshold, and exceeding this addition level may weaken the beneficial effects on microbial biomass, metabolic activity, and the relative carbon accumulation advantage of the planting system. Full article

The Con Dao archipelago hosts the oldest MPA in Vietnam and is recognized as a regional marine biodiversity hotspot. Here, we applied environmental DNA (eDNA) metabarcoding to assess coastal fish diversity across four major habitat types: coral reefs, seagrass beds, mangroves, and a harbour in the Con Dao archipelago. Using MiFish-U 12S primers at eight stations, we detected 282 operational taxonomic units, corresponding to 144 fish taxa. Fish assemblages exhibited strong habitat structuring: community composition differed markedly among habitats, with minimal overlap. Only three species were shared across all habitats. Multivariate analyses confirmed that habitat type, rather than spatial distance among sites, was the primary driver of community differentiation. Mangrove and seagrass supported distinct assemblages that were underrepresented in existing species checklists and MPA management frameworks. Notably, eDNA detected cryptic and non-commercial species overlooked by conventional survey methods. These results substantially expand the known fish diversity of the Con Dao Archipelago and highlight the need to incorporate habitat heterogeneity, particularly non-reef ecosystems, into MPA design and monitoring. Although eDNA metabarcoding is subject to amplification biases and limited taxonomic resolution in reference databases, it offers a powerful complement to traditional surveys for characterizing under-sampled habitats. Full article

Martinique sponge fauna was largely undocumented until 2017, when the first inventory of Porifera colonizing coral reefs, mangroves and caves around the island was published. We performed an integrative classification of sponges in the foraging area of hawksbill turtle (Eretmochelys imbricata) in Martinique. Sponge specimens were retrieved as direct or indirect diet items consumed by hawksbill turtles after video observations, and the feeding behaviors of these predators were tracked. Morphology was supplemented with molecular identification (DNA barcoding) based on a multi-locus approach using COI, 28S and ITS genetic markers. Seventeen different species were identified, belonging to seven orders: Poecilosclerida, Dictyoceratida, Verongiida, Agelasida, Haplosclerida, Clionaida, and Tetractinellida. Haplosclerida exhibited the greatest diversity and species abundance, followed by Verongiida. The 28S marker provided the highest confidence in species identification. We provided new barcode records for Hyattella cavernosa and Amphimedon caribica. Among the cataloged sponges, only four of them had been previously reported as food items of E. imbricata (Xestospongia muta, Iotrochota birotulata, Spirastrella coccinea and Cinachyrella kuekenthali). The rest represent newly documented items that are potentially preyed upon by this turtle predator. The characterization of sponges as being part of the feeding habitat of hawksbill turtles underpins management and protection plans for this critically endangered species, and the benthic community on which they feed, by providing criteria for generating networks of Marine Protected Areas (MPAs) in the Caribbean regions. Full article

Tropical cyclones rank among the most destructive natural hazards globally, posing significant threats to coastal ecosystems and communities. Mangrove forests, renowned for their ecological importance and coastal protection services, are vulnerable to these disturbances, suffering structural damage, habitat loss, and disruption of vital ecosystem functions. Conventional field-based assessment methods often fall short in capturing the rapid and widespread impacts of cyclones, particularly in remote or cloud-obscured regions. This review aims to provide a comprehensive synthesis of remote sensing applications for monitoring cyclone-induced impacts on mangrove and coastal ecosystems worldwide. Through a systematic literature review of 74 peer-reviewed articles from 1990 to 2025, the study evaluates the utility of optical sensors, radar systems, and multi-sensor platforms in assessing inundation, vegetation damage, and ecosystem service loss. Key methodological advances such as time-series analysis, machine learning, and UAV-based validation are highlighted, alongside critical gaps including limited geographic coverage, weak validation practices, and minimal socio-economic integration. Notably, 75.4% of reviewed studies are concentrated in Asia, with Bangladesh and India alone accounting for 44.6% of the total literature, underscoring a pronounced geographic bias. The findings underscore the need for robust, near-real-time monitoring frameworks that combine satellite technologies with ground data and community engagement. Ultimately, the review advocates for an integrated, multi-sensor, and participatory approach to cyclone resilience, offering valuable insights for future research, disaster response planning, and sustainable mangrove management. Full article

Nature-based Solutions (NbS) have emerged as transformative approaches to address societal challenges, support biodiversity, and enhance human well-being. Globally, NbS are recognized for their potential to mitigate climate change impacts such as coastal flooding. Despite growing policy interest, limited empirical evidence exists on their real-world effectiveness, particularly in Africa. The core objective of this study was to evaluate how community perceptions, awareness, and demographic factors influence the acceptance and effectiveness of NbS for flood risk reduction in selected coastal communities of Rivers State, Nigeria. Specifically, it aimed to assess community perceptions and awareness of NbS, identify demographic, geographic, and psychosocial factors influencing these perceptions, and analyze how risk perception and local knowledge affect acceptance. The study addressed three key questions: (1) How do community perceptions affect NbS acceptance and implementation? (2) What factors shape awareness and understanding of NbS in Kula, Oyorokoto, and Bonny? (3) How do perceptions vary across demographic groups? To answer these, a structured survey of 1224 respondents was conducted: 61% were male and 39% female, with most aged 31–50 years (80%). Education emerged as a key factor—about 49% of respondents had at least secondary or post-secondary education, which showed a significant link with positive perceptions of NbS (χ² = 460.98, p < 0.001, Cramer’s V = 0.434). Occupation also shaped views: traders (36.8%) and fishers (24.5%) formed the majority, with occupational patterns showing moderate influence (χ² = 112.68, p < 0.001, Cramer’s V = 0.215). Overall, awareness was the strongest predictor, with communities reporting higher NbS awareness demonstrating significantly greater acceptance (OR = 0.06, p < 0.001). These findings highlight that targeted awareness-raising, education, and community engagement are critical to promoting mangrove conservation, afforestation, and ecosystem restoration, ultimately strengthening resilience to climate-induced risks in coastal communities. Full article

Effective and cost-efficient monitoring is crucial in wetland management strategies. Large-scale surveys are time-consuming and uneconomical. Therefore, choosing between smaller-scale or alternative surveys is an important consideration in monitoring strategies. Indicator species (IS) are single species or a small number of target species that use specific characteristics as proxies or paradigms to represent community status or environmental indicators. To interpret and monitor changes caused by mangrove removal, we applied principal component analysis (PCA) and proposed a new concept to reveal the contribution of species to each principal component, thereby quantitatively identifying selectable ISs in environmental change. ISs were selected based on the total cumulative load of each species and the load of each species in each component. According to the load score algorithm in PCA, we identified five indicator species, namely, M. brevidactylus, M. banzai, U. arcuata, U. lacteal, and U. borealis. These ISs can clearly highlight changes during mangrove removal. PCA effectively reveals the relative changes of organisms across principal components by highlighting patterns and trends. It helps to detect environmental anomalies and assess their trends. Full article

Monitoring the α-biodiversity indicators of mangrove forests and understanding their spatiotemporal trends can guide mangrove restoration strategies. Taking Qinglan Port in Hainan Province, China, as our study area, we compared multiple machine learning methods to predict the spatial distribution of α-biodiversity indicator Shannon’s diversity index (SHDI) by integrating LiDAR points and Worldview-2 images. In addition, the relationship between mangrove forests’ SHDI values and growth years was analyzed. The study extracted 28 spectral features and 99 LiDAR features from Worldview-2 and LiDAR data, respectively. The RReliefF method was adopted to select informative features. Four machine learning methods, including support vector machines (SVMs), extreme gradient boosting (XGBoost), deep neural networks (DNNs), and Gaussian process regression (GPR), were used to establish SHDI prediction models. The leave-one-out cross-validation (LOOCV) method was used to evaluate prediction accuracy, and the optimal model was adopted to generate a spatial map of SHDI. Based on Google Earth and Worldview-2 images, the spatial regions of mangrove forests in 2008, 2013, 2018, and 2023 were identified. The SHDI values within different restoration periods were statistically analyzed by using the mangroves’ spatiotemporal distributions. The results showed that RReliefF selected a total of 30 features, including 13 spectral features and 17 LiDAR features. Using preferred features, GPR had the highest prediction accuracy, with an LOOCV R² of 0.51, followed by SVM (R² = 0.44) and DNN (R² = 0.32); the accuracy of XGBoost (R² = 0.29) was relatively poor. The increased areas of rehabilitated mangrove forests in the periods of 2008–2013, 2013–2018, and 2018–2023 were 0.31 km², 0.13 km², and 1.35 km², respectively. Mangroves growing before 2008 owned the highest mean SHDI value of 0.74, followed by mangroves in 2008–2013 and 2013–2018; mangrove forests restored in 2018–2023 had the lowest mean SHDI value of 0.63. The results indicated that mangrove SHDI can be predicted by integrating LiDAR and Worldview-2. The mangrove population exhibited more diverse α-biodiversity characteristics as growth time increased. In subsequent mangrove restoration processes, planting mangroves of diverse species is beneficial to ensure the stability of the mangrove community. Full article

Coastal pond-to-mangrove restoration has become a prominent Nature-based Solution, yet its short-term ecological effects on waterbird communities remain unclear. We assessed taxonomic, functional, and compositional responses of waterbirds to large-scale restoration in Bamen Bay, Hainan Island, using BACI-style comparisons between restored and unrestored aquaculture ponds in 2021 and 2023. Restored areas exhibited higher taxonomic α diversity and functional richness (p < 0.001), coinciding with rapid habitat diversification following hydrological reconnection. Species richness (p < 0.001), Shannon diversity (p < 0.01), and functional richness (p < 0.01) were consistently higher in restored areas than in aquaculture ponds. In contrast, β diversity patterns diverged between habitats: restored areas remained relatively stable, whereas aquaculture ponds showed greater between-year compositional change (p < 0.05). Guild-specific responses revealed contrasting patterns: herons showed higher diversity in restored habitats (p < 0.05), whereas shorebirds exhibited no significant changes (p > 0.05), consistent with their dependence on open mudflats that were only partially retained. Although no significant declines were detected, functional richness tended to be lower in 2023 (p > 0.05), and ongoing mudflat loss suggests potential long-term risks for mudflat specialists, warranting extended monitoring. Taken together, our findings suggest that effective pond-to-mangrove restoration in Bamen Bay should balance mangrove expansion with the retention of tidal flats and managed shallow-water habitats to support diverse waterbird assemblages. Full article

The continuous degradation of mangrove ecosystems, considered among the most vulnerable worldwide, reveals multiple threats driven by human activities and climate change. In the Peruvian context, particularly in the Tumbes Mangrove ecosystem, these pressures are intensified by the absence of integrated spatial and educational infrastructures capable of supporting conservation efforts while engaging local communities. In response, this research proposes a Sustainable Interpretation Center for Conservation and Environmental Education in Ecologically Sensitive Areas of the Tumbes Mangrove, Peru. The methodology includes climate data analysis, identification of local flora and fauna, and site topography characterization, supported by digital tools such as Google Earth, AutoCAD 2025, Revit 2025, and 3D Sun Path. The results are reflected in an architectural proposal that incorporates sustainable materials compatible with sensitive ecosystems, including eco-friendly structural solutions based on algarrobo timber, together with resilient strategies addressing climatic variability, such as lightweight structures, elevated platforms, and passive environmental solutions that minimize impact on the mangrove. Furthermore, the proposal integrates a photovoltaic energy system consisting of 12 solar panels with a unit capacity of 450 W, providing a total installed capacity of 5.4 kWp, complemented by a 48 V LiFePO₄ battery storage system designed to ensure energy autonomy during periods of low solar availability. In conclusion, the proposal adheres to principles of sustainability and energy efficiency and aligns with the Sustainable Development Goals (SDGs) 7, 8, 12, 14, and 15, reinforcing the use of clean energy, responsible tourism, sustainable resource management, and the conservation of marine and terrestrial ecosystems. Full article

Sympatric species are closely related taxa that coexist within the same habitat through niche partitioning, and kingfishers serve as an ideal group for studying such ecological mechanisms. The present study examined the perch height in relation to foraging behaviour and hunting success of five kingfisher species: Common Kingfisher (Alcedo atthis), White-throated Kingfisher (Halcyon smyrnensis), Pied Kingfisher (Ceryle rudis), Stork-billed Kingfisher (Pelargopsis capensis), and Black-capped Kingfisher (Halcyon pileata). The study was conducted between 2021 and 2023, across seven habitat types in Kerala, India (Kadalundi–Vallikkunnu Community Reserve (KVCR) mangroves, Kallampara mangroves, Vadakkumpad mangroves, Vazhakkad agroecosystem, Mavoor wetland, Sanketham wetland, and Elathur beach). A generalized linear mixed model (GLMM) with a binomial distribution and logit link function was used to analyze hunting success across species. The model indicated that the effect of perch height on hunting success varied among species, though neither perch height nor species identity alone had a significant effect. Most species favored mid-height perches (2–5 m) for foraging, with the Common Kingfisher exhibiting moderate success across all heights and habitats. The Pied Kingfisher showed significantly reduced success at higher perches, while the Stork-billed Kingfisher achieved the highest success at mid-heights (2–5 m). The White-throated Kingfisher showed a non-significant negative association with capture success, whereas the Black-capped Kingfisher exhibited a neutral to positive relationship across perch heights. Among all variables tested, prey availability emerged as the sole significant predictor of hunting success, indicating that prey abundance is the principal determinant of foraging efficiency in tropical wetlands, rather than environmental conditions. Our findings confirm a pattern of vertical stratification in resource partitioning among sympatric kingfisher species and underscore the importance of conserving habitats that retain natural perch sites of varying heights. Full article

Sonneratia alba Sm. and Sonneratia caseolaris (L.) Engl. are two ecologically important components of mangrove communities in Thailand. However, their population genetic patterns in Thailand remain poorly understood. Here, we assessed the genetic diversity and population structure of 107 S. alba and 131 S. caseolaris individuals sampled across their full coastal range in Thailand using single-nucleotide polymorphism (SNP) markers. Population structure analyses consistently revealed strong genetic subdivision associated with geography: S. alba formed three clusters (including one admixed group), whereas S. caseolaris formed two clusters. In both species, populations were clearly separated between the Andaman Sea and the Gulf of Thailand, reflecting the isolating influence of the Malay Peninsula. Genetic differentiation between clusters was high (F_ST = 0.364 in S. alba and 0.321 in S. caseolaris). Genetic differentiation increased with geographic distance in S. caseolaris, whereas no such relationship was detected in S. alba. Both species exhibited low levels of genetic diversity (H_o = 0.173; H_e = 0.223 in S. alba and H_o = 0.290; H_e = 0.406 in S. caseolaris). Together, these results reveal pronounced spatial genetic structure and limited evolutionary connectivity between coastal regions, providing genome-wide insights into mangrove population differentiation with important implications for conservation and restoration. Full article