Search Results (359)

To evaluate the early-stage effects of different mangrove species on macrobenthic communities along the southern coast of Quanzhou Bay, this study examined restoration sites dominated by K. obovata (Q), A. corniculatum (T), and A. marina (B), together with an adjacent unvegetated mudflat (Y). Sediment physicochemical properties, species composition, density, biomass, diversity indices, abundance-biomass comparison (ABC) curves, and cluster/NMDS results were compared before mangrove planting and during the spring and autumn after planting. The results showed that sediment backgrounds were relatively similar among sites before planting. After planting, total carbon (TC) and total nitrogen (TN) increased in autumn, and the number of macrobenthic species increased from 13 before planting to 24 after planting. Species number, density, and diversity were generally higher in autumn than in spring. Redundancy analysis (RDA) further showed that the relationships between sediment environmental variables and macrobenthic community metrics varied across restoration stages. Before planting, the three original sites showed relatively weak separation along the environmental gradients. After planting, the ordination pattern became more structured. In spring, biomass was mainly associated with the A. marina site, whereas TC and TN were more closely related to the K. obovata site. In autumn, TN and biomass were more closely associated with the A. corniculatum and A. marina sites, while TC, TP, and salinity were more strongly related to the K. obovata site. These results indicate that sediment carbon and nitrogen dynamics, together with salinity and pH gradients, jointly shaped macrobenthic community recovery during the early restoration stage. The A. corniculatum site had the highest density and biomass in autumn and showed relatively high abundance-biomass comparison (ABC)-based community stability, as indicated by positive W values and biomass curves generally lying above abundance curves. The A. marina site had relatively high species richness and diversity, whereas the recovery performance of the K. obovata site was comparatively weaker. Overall, A. corniculatum and A. marina are more suitable as the main species for mangrove restoration along the southern coast of Quanzhou Bay, while K. obovata can be used as an auxiliary species in mixed planting. Full article

Hyblaea puera is a major pest of teak and mangroves. Reliable RT-qPCR normalization requires stable reference genes, none of which have been validated in H. puera. In this study, we assessed the expression stability of ten candidate reference genes under different experimental conditions. Stability was evaluated using the ΔCt method, BestKeeper, NormFinder, and geNorm, and a comprehensive stability ranking was generated using the RefFinder online tool. Our results indicated that amplification efficiencies ranged from 91.67% to 100.82%, with R² values exceeding 0.9901. The optimal reference gene combinations varied by condition: Ribosomal Protein L27 (RPL27) and Ribosomal Protein L10 (RPL10) for temperature treatments; Actin and RPL10 for larval instars; Ribosomal protein S5 (RPS5) and Elongation factor-1α (EF-1a) for adult sexes; RPL10 and EF-1a for tall developmental stages; RPL10 and RPS5 for tissues; as well as EF-1α and Actin for all combined conditions. Finally, the expression profiles of target gene Lethal were evaluated, and the outcomes further confirm the importance of selecting fitting reference genes for normalization of qRT-PCR data. These results provide the evaluated reference gene sets for H. puera, facilitating more accurate RT-qPCR normalization in future molecular studies of host plant adaptation (teak vs. mangroves), temperature tolerance, and larval development in this pest. Full article

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

Reliable nursery production is essential for producing ex situ planting stock of the locally threatened mangrove Lumnitzera littorea in Can Gio, Vietnam. We evaluated 12-month seedling performance using two nursery substrates—CTI (topsoil) and CTII (mixed substrate)—and salinity-structured irrigation regimes: C, a dynamic river/tidal water plus freshwater reference regime and seven fixed-salinity treatments (E1–E7: 0, 10, 15, 20, 25, 30, and 35‰). Each substrate–regime combination comprised three replicate cells of 40 seedlings (N = 1920). The primary endpoints were month 12 survival (SR12), seedling height among survivors (H12), and root collar diameter among survivors (Do12). Statistical inference was confined to E1–E7; C was retained as a descriptive operational reference. For E1–E7, substrate and regime significantly affected SR12 and H12, whereas Do12 varied by regime but not by substrate; no substrate × regime interaction was detected. SR12 declined sharply at 30–35‰, especially under CTI, and the high-salinity H12 and Do12 estimates were based on few survivors. CTII outperformed topsoil alone, particularly for survival and survivor-conditioned height. The findings support conservative nursery guidance for Can Gio: use a mixed substrate and avoid sustained high fixed-salinity irrigation, without extending the inference to a species-wide salinity optimum or post-planting field performance. Full article

The microbes found in the rhizosphere, roots, leaves and stem surfaces and within the internal tissues of mangrove vegetation and their environment constitute the microbiome of the ecosystem. The organisms in the microbiome include bacteria, protozoa, fungi, algae, amoebas, and slime molds, which assist in maintaining and restoring mangrove ecosystems. This review explores the role of microbiomes in the maintenance of healthy mangrove ecosystems and in the successful restoration of degraded mangrove ecosystems. Microbes have important roles in several geomicrobiological cycles shaping mangrove ecosystems, including transforming nitrogen, phosphorus, carbon, sulfur and iron in biogeochemical cycles. Mangrove microbiomes contribute to the adaptation of vegetation to the harsh abiotic conditions in coastal areas, enhance nutrient uptake, produce plant-growth-promoting substances, and degrade the mangrove litter and the pollutants that can hinder restoration. Soil microbes function as biofertilizers, biopesticides, and bioremediation agents. The microbial diversity, composition, and functional capacity are important in the restoration of mangroves through their influence on voluntary recruitment following hydrologic restoration, on the establishment success of planted seeds and propagules, and on the survival of transplanted saplings and nursery-raised seedlings. The knowledge of the beneficial attributes of the microbiome can enhance the overall success of mangrove restoration. Identifying future needs, such as microbial inoculant validation, field-scale trials, and integration with hydrological restoration, are essential. 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

Rice (Oryza sativa L.) production is severely threatened by rice blast disease caused by the hemibiotrophic fungus Magnaporthe oryzae. Chemical fungicides, although effective, cause environmental pollution, disrupt soil microbiomes, and select for resistant pathogen populations, creating an urgent need for sustainable alternatives. In this study, we isolated Kitasatospora hibisci strain 21007 from mangrove soil and evaluated its biocontrol potential through integrated phenotypic and transcriptomic analyses. The cell-free culture filtrate (CFCF) extract showed potent antifungal activity, inhibiting M. oryzae mycelial growth and suppressing conidial germination as well as appressorium formation in a concentration-dependent manner via antibiosis. Fermentation optimization identified Gauze’s Synthetic Medium No. 1 as optimal for metabolite production. Both inoculation of M. oryzae spores with 21007 CFCF extract and pre-treatment of rice seedlings with 21007 CFCF significantly reduced disease severity under greenhouse conditions. Transcriptomic analysis revealed extensive reprogramming of gene expression in leaves of rice seedlings cultured with 21007 CFCF extract. KEGG pathway enrichment analysis indicated activation of the plant–pathogen interaction and MAPK signaling pathways in rice seedlings cultured with 5% and 10% CFCF extract, suggesting that 21007 CFCF induces host defense signaling. These results support the potential of K. hibisci 21007 as a candidate for sustainable biocontrol of rice blast disease and establish a foundation for future metabolomic and genomic investigations. 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

Mangroves are important coastal wetland ecosystems with high ecological service values and strong carbon sequestration capacity, serving as a crucial barrier for coastal ecological security. However, current afforestation efforts often ignore environmental suitability differences among mangrove species, while the applicability value and ecological risks of exotic species (Laguncularia racemosa and Sonneratia apetala) for restoration remain poorly understood. Five native and two exotic mangrove species along China’s coasts were selected in this study. Using the MaxEnt model, we identified key environmental factors governing their distribution, predicted their current and future suitable habitats (under the SSP245 scenario in the 2070s), and quantified niche overlap between native and exotic mangroves. The results showed that temperature-related factors (air and sea temperature) are the core climatic drivers shaping the typical mangrove distribution, followed by sea surface salinity, with precipitation contributing little. Currently, niche overlap between native and the two exotic species is low (D.overlap: 0.129–0.340), indicating certain niche differentiation. Under the SSP245 scenario in the 2070s, except for Rhizophora stylosa, other studied species appear to experience expanded suitable habitat areas and a northward latitudinal distribution shift. Compared with Sonneratia apetala, Laguncularia racemosa exhibits a more pronounced expansion of suitable habitats in the future, with its overall suitable area second only to the native Kandelia obovata, indicating its stronger adaptive potential to climate change. Clarifying niche differentiation and constructing species-specific management frameworks may facilitate biological invasion control, mangrove restoration, and species diversity improvement. Full article

Mangroves are crucial for biodiversity conservation, coastal protection, and supporting local livelihoods. Mangroves may also protect coasts from storms and rising sea levels and can play a major role in climate mitigation. Threats to their health include activities such as infrastructural development, urban encroachment, aquaculture and crop farming, and oil and gas exploration. We review the threats and opportunities for the restoration of mangrove ecosystems on the coasts of Africa, which are highly impacted by oil spills. The most important challenge for mangrove restoration identified in this review is the restoration of appropriate hydrologic and salinity regimes prior to natural recruitment or the active planting of propagules. Full article

To explore the patterns of biomass accumulation and sediment carbon burial indicators in mangrove forests under different thinning intensities, a study was conducted on an 8-year-old Kandelia obovata Sheue & al. plantation on Shupaisha Island, Longwan District, Wenzhou City, Zhejiang Province. Three treatments were designed: no thinning (CK), 20% thinning, and 40% thinning. Stand growth and plant carbon density were evaluated for all three treatments at the initial thinning stage and two years later. Sediment carbon density and organic carbon burial rate were assessed only for CK and 20% thinning. Thinning significantly enhanced mangrove growth and plant carbon storage. Compared with unthinned stands, 20% and 40% thinning treatments significantly increased branch diameter and biomass (p < 0.05). The order of mangrove height was 20% thinning > 40% thinning > CK. The plant carbon densities in the 20% and 40% thinned stands were 16.31 Mg C·ha⁻¹ and 15.30 Mg C·ha⁻¹, respectively, far exceeding that of the control (4.80 Mg C·ha⁻¹). In contrast, sediment carbon responses were negative in the short term. After thinning, the sedimentation rate and organic carbon content in mangrove sediments decreased. Sediment carbon density decreased from 88.10 Mg C·ha⁻¹ in unthinned stands to 85.02 Mg C·ha⁻¹ under 20% thinning, accompanied by a reduction in carbon burial rate. Overall, these two-year results indicate increased plant carbon storage under thinning, whereas measured sediment carbon indicators under moderate thinning declined over the same period. Longer-term monitoring is needed to assess whether these short-term responses translate into net ecosystem carbon consequences. Full article

Subtropical forest ecosystems, especially evergreen broad-leaved forests in the East Asian monsoon region, are a crucial component of the global terrestrial carbon cycle and make a key contribution to the “missing carbon sequestration” in the Northern Hemisphere. This review systematically integrates recent research progress on the carbon pool patterns, aboveground-subsurface biogeochemical processes, and global change responses of subtropical forests, summarizing the potential mechanisms of their sustainable carbon sequestration capacity and identifying current cognitive bottlenecks. Studies have shown that subtropical mature forests have carbon sequestration potential that exceeds traditional theoretical expectations, but there are still significant shortcomings in terms of carbon stability in deep soil (>1 m), quantitative constraints on rhizosphere activating effects, and assessment of ecosystem resilience under extreme climate events. Furthermore, the nonlinear interactions between factors such as climate warming, precipitation changes, and nitrogen deposition may trigger a critical turning point in carbon sink functions, and the water-carbon-geological coupling processes in special habitats such as karst and mangrove forests are often underestimated. We further propose that future research should focus on developing coupled models of “plant–soil–microbe hydrology”, combining molecular and isotopic techniques to elucidate microbial carbon pump mechanisms and strengthening long-term in situ experiments under combined extreme events to provide scientific support for subtropical forest carbon sink management and prediction. Full article

Anthropogenic activities interact through multifactorial processes that generate harmful factors, hindering wastewater management (WWM) and causing environmental degradation, particularly in rapidly urbanizing coastal regions. Understanding how these processes operate is essential for identifying effective interventions under data-limited conditions. This study introduces a process-based and context-driven approach whose main contribution lies in the construction of semantic pathways that represent how indirect anthropogenic drivers give rise to direct harmful factors affecting WWM and the environmental state. Semantic networks are used as a formal representation tool to model these pathways, where nodes represent factors and directed arcs represent causal relationships. Harmful semantic pathways are evaluated within a multidisciplinary decision-making framework supported by multi-criteria decision-making (MCDM) methods that account for environmental, social, economic, and sustainability criteria. The approach is applied to a coastal tourist municipality on the Mexican Pacific coast, where rapid urban expansion and insufficient basic services have severely constrained wastewater management and contributed to environmental damage. Results show that constructing and analyzing semantic pathways enables decision-makers to identify critical harmful factors and prioritize viable pro-environmental actions. The resulting priorities (range 0–1) highlight the restoration of wastewater treatment plants and improved urban planning as the most effective interventions, followed by mangrove reforestation and changes in agricultural practices. The proposed approach supports transparent, context-sensitive decision-making and is transferable to coastal tourist municipalities facing similar wastewater management challenges. 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