Search Results (91)

Vegetation succession is a critical indicator of ecosystem structure and function and is often disrupted by the expansion of invasive species. However, ecosystem-scale studies elucidating invasion-driven succession mechanisms remain limited. This research focused on the Yancheng coastal salt marsh and analyzed the distribution variation of invasive species (Spartina alterniflora) and native species (Suaeda salsa and Phragmites australis) from 1987 to 2022 via the Google Earth Engine and random forest method. Logistic/Gaussian models were used to quantify land–sea distribution changes and vegetation succession trajectories. By integrating data on soil salinity, invasion duration, and fractional vegetation cover, generalized additive models (GAMs) were applied to identify the main factors influencing vegetation succession and to explore how Spartina alterniflora invasion affects the succession of salt marsh vegetation. The results indicated that the areas of Spartina alterniflora and Phragmites australis significantly increased by 3787.49 ha and 3452.60 ha in 35 years, respectively, contrasting with Suaeda salsa’s 82.46% decline. The FVC in the area has significantly increased by 42.10%, especially in the coexisted areas of different vegetation communities, indicating intensified interspecific competition. The overall trend of soil salinity was decreasing, with a decrease in soil salinity in native species areas from 0.72% to 0.37%. From the results of GAMs, soil salinity, tidal action, and invasion duration were significant factors influencing the distribution of native species, but salinity was not a significant factor affecting the Spartina alterniflora distribution. The findings revealed that the expansion of Spartina alterniflora changed the soil salinity and interspecific interactions, thereby altering the original plant community structure and establishing a new vegetation succession. This study enhances the understanding of the impacts of invasive species on ecosystems and offers theoretical support for salt marsh restoration. Full article

Soil saline–alkaline stress and water stress, exacerbated by anthropogenic activities and climate change, are major drivers of wetland vegetation degradation, severely affecting the function of wetland ecosystems. In this study, we conducted a simulation experiment with three water levels and four saline–alkaline concentration levels as stress factors to assess eight key functional traits of Phragmites australis and Bolboschoenus planiculmis, dominant species in the salt marsh wetlands in the western region of Jilin province, China. The study aimed to evaluate how these factors influence the functional traits of P. australis and B. planiculmis. Our results showed that the leaf area, root biomass, and clonal biomass of P. australis significantly increased, and the leaf area of B. planiculmis significantly decreased under low and medium saline–alkaline concentration treatments, while the plant height, ramet number, and aboveground biomass of P. australis and the root biomass, clonal biomass, and clonal/belowground biomass ratio of B. planiculmis were significantly reduced and the ratio of belowground to aboveground biomass of B. planiculmis significantly increased under high saline–alkaline concentration treatment. The combination of drought conditions with medium and high saline–alkaline treatments significantly reduced leaf area, ramet number, and clonal biomass in both species. The interaction between flooding water level and medium and high saline–alkaline treatments significantly suppressed the plant height, root biomass, and aboveground biomass of both species, with the number of ramets having the greatest contribution. These findings suggest that the effects of water levels and saline–alkaline stress on the functional traits of P. australis and B. planiculmis are species-specific, and the ramet number–plant height–root biomass (RHR) strategy may serve as an adaptive mechanism for wetland clones to environmental changes. This strategy could be useful for predicting plant productivity in saline–alkaline wetlands. Full article

Climate change and rising soil salinization pose significant challenges to agriculture and food security, particularly in coastal regions. Halophytes, salt-tolerant plants thriving in saline environments, offer promising solutions, as they show resilience to extreme conditions and provide nutritional and ecological benefits. This study investigates the potential of edible halophytes in the Mediterranean Basin, focusing on Tuscany’s salt marshes. A combination of literature reviews and field surveys identified 24 edible species among 60 recorded halophytes. These plants, mainly from the Amaranthaceae family, ranging from seasonal therophytes to perennial geophytes, display diverse life forms and adaptive strategies for saline habitats. The study highlights their nutritional and economic value, with edible parts such as leaves and shoots rich in essential minerals and antioxidants. Fieldwork and geospatial analyses revealed distinct patterns of species distribution, emphasizing the role of halophytes in maintaining ecosystem resilience and offering sustainable agricultural opportunities in degraded lands. By mapping their distribution and analyzing biodiversity indices, this research underscores the importance of conserving halophyte species as genetic resources and advancing their integration into agricultural systems. The findings provide a basis for developing innovative approaches to enhance food security in saline-affected areas. Full article

Candida infections severely impact patients who are immunocompromised. Currently, there are limited options to treat fungal infections, especially drug-resistant-fungal infections. Therefore, investigating alternative or repurposed antifungals is paramount. Endophytic microbes (EMs) and rhizospheric microbes (RMs) emerge as promising reservoirs of bioactive natural compounds. Interestingly, plants that have adapted to various environmental conditions harbour a plethora of microbes producing a variety of bioactive natural products that can be assessed for potential antifungal activity. To date, EMs and RMs residing in coastal plants and their associated antifungals have not been extensively studied or reviewed. Therefore, this comprehensive review will focus on antifungal natural products, extracted from coastal-vegetation-associated microbiota to draw the attention of research in this field. A comprehensive literature search was conducted by examining both Scopus and Google Scholar databases during the period of 2013–2024 related to the following coastal vegetation: mangroves, sand dune plants, salt marsh plants, and seagrasses. To date, 65 novel antifungal compounds derived from coastal-plant EMs and RMs have been identified. Mangroves were found to be the most prominent host harbouring antifungal-producing EMs and RMs compared with other coastal plants. Coastal-plant-associated fungal partners were the most prominent producers of antifungals compared to their bacterial counterparts. Fifty-four fungal-EM/RM derived antifungals have been reported to demonstrate activities against plant pathogenic fungi as well as human fungal pathogens. Most of the bacterial-derived antifungals (11 antifungals) have previously been reported to have antifungal activity against Candida albicans. Full article

Reducing carbon emissions and increasing carbon sinks have become the core issues of the international community. Although coastal blue carbon ecosystems (such as mangroves, seagrass beds, coastal salt marshes and large algae) account for less than 0.5% of the seafloor area, they contain more than 50% of marine carbon reserves, occupying an important position in the global carbon cycle. However, with the rapid development of the economy and the continuous expansion of human activities, coastal wetlands have suffered serious damage, and their carbon sequestration capacity has been greatly limited. Ecological restoration has emerged as a key measure to reverse this trend. Through a series of measures, including restoring the hydrological conditions of damaged wetlands, cultivating suitable plant species, effectively managing invasive species and rebuilding habitats, ecological restoration is committed to restoring the ecological functions of wetlands and increasing their ecological service value. Therefore, this paper first reviews the research status and influencing factors of coastal wetland carbon sinks, discusses the objectives, types and measures of various coastal wetland ecological restoration projects, analyzes the impact of these ecological restoration projects on wetland carbon sink function, and proposes suggestions for incorporating carbon sink enhancement into wetland ecological restoration. Full article

Salt marshes are vital coastal ecosystems, increasingly threatened by rising sea level and human pressures, that provide essential services, including coastal protection, habitat support, and carbon sequestration. This study examines the effectiveness of different eco-engineering structures in restoring salt marshes in the Mondego Estuary, Portugal, by assessing their impacts on benthic macroinvertebrate communities as bioindicators of ecosystem health. The experimental design included five experimental cells: wood palisade (Fence), geotextile fabric (Geotextile), geotextile bags filled with sand (Bags), a cell with autochthonous vegetation (Plants), and a Control cell with bare soil. Monitoring took place from 2019 to 2021, with both before and after intervention sampling to evaluate species composition, biomass, and density. Key ecological indices, such as the AZTI’s Marine Biotic Index (AMBI), Shannon-Wiener Diversity, and Pielou’s Evenness, were calculated alongside measurements of environmental variables. The results indicated minimal impacts on biodiversity, with observed variations primarily attributed to seasonal dynamics. While the wood palisade enhanced species richness and density, geotextile provided better community stability. The findings emphasize the importance of long-term monitoring, stakeholder engagement, and sustainable use of materials to optimize restoration efforts and better inform coastal management strategies in the face of climate change. Full article

This study aimed to isolate salt-tolerant pectinolytic bacteria from the rhizosphere of a salt marsh plant and utilize their pectinases for the clarification of detox juice preparation. Sixteen halophilic bacterial strains were isolated from the rhizospheric soil of Arthrocnemum macrostachyum. The isolates were screened for pectinase activity, and two strains, ASA21 and ASA29, exhibited the highest pectinase production in the presence of 2.5% NaCl, reaching 13.3 and 14.1 IU mL⁻¹, respectively. The strains were identified as Bacillus paralicheniformis and Paenibacillus sp. by 16S rDNA sequencing and phylogenetic analysis. Growth kinetics and pectinase production studies revealed that both strains produced pectinase during the log phase, with ASA29 demonstrating higher growth and pectinase titers. The pectinase from ASA29 exhibited enhanced activity in the presence of 3% NaCl. The pectinases from both strains were applied for the clarification of detox juice prepared from beetroot, carrots, and apples. The use of 20 IU mL⁻¹ pectinase from ASA29 for 2–3 h yielded > 96% juice with high total phenolic content and antioxidant activities. This study highlights the potential of salt-tolerant pectinolytic bacteria from the rhizosphere for biotechnological applications, particularly in the clarification of juices with high salt content. Full article

Mangroves are one of the world’s most productive and ecologically important ecosystems, and they are threatened by the widespread invasion of Spartina alterniflora Loisel in China. As few studies have examined the spatial pattern differences of S. alterniflora invasion and the nearby mangroves in different latitudes, we chose the Zhangjiang Estuary and the Dandou Sea, two representative mangrove–salt marsh ecotones in the north and south of the Tropic of Cancer, as the study areas for comparison. The object-based image analysis and visual interpretation methods were combined to construct fine-scale mangrove and S. alterniflora maps using high-resolution satellite imagery from 2005 to 2019. We applied spatial analysis, centroid migration, and landscape indexes to analyze the spatio–temporal distribution changes of mangroves and S. alterniflora in these two ecotones over time. We used the landscape expansion index to investigate the S. alterniflora invasion process and expansion patterns. The annual change rates of mangrove and S. alterniflora areas in the Zhangjiang Estuary showed a continuous growth trend. However, the mangrove areas in the Dandou Sea showed a fluctuating trend of increasing, decreasing, and then increasing again, while S. alterniflora areas kept rising from 2005 to 2019. Spartina alterniflora showed larger annual change rates compared with mangroves, indicating rapid S. alterniflora invasion in the intertidal zones. The opposite centroid migration directions of mangroves and S. alterniflora and the decreasing distances between the mangrove and S. alterniflora centroids indirectly revealed the fierce competition between mangroves and S. alterniflora for habitat resources. Both regions saw a decrease in mangrove patch integrality and connectivity. The integrality of mangrove patches in the Zhangjiang Estuary was always higher than those in the Dandou Sea. We observed the growth stage (2011–2014) and outbreak stage (2014–2019) of S. alterniflora expansion in the Zhangjiang Estuary and the outbreak stage (2005–2009) and plateau stage (2009–2019) of S. alterniflora expansion in the Dandou Sea. The expansion pattern of S. alterniflora varies in time and place. Since the expansion of S. alterniflora in the outbreak stage is rapid, with a large annual change rate, early warning of S. alterniflora invasion is quite important for the efficient and economical removal of the invasive plant. Continuous and accurate monitoring of S. alterniflora is highly necessary and beneficial for the scientific management and sustainable development of coastal wetlands. Full article

Smooth cordgrass (Spartina alterniflora) is a native salt marsh plant along the Atlantic coast but has become an invasive species in coastal regions in China, as well as other areas. Utilizing it for resources has become a control measure in reducing the spread of S. alterniflora. This study assesses the nutritional and phytochemical properties of the edible stems of S. alterniflora collected from three locations in Fujian province, China. The tender stems of S. alterniflora exhibit a rich nutritional profile, with high levels of protein, carbohydrates, and fats, and significant amounts of essential vitamins, minerals, and antioxidants, indicating their potential as a nutritious addition to the diet or forage. In addition, the levels of potential contaminants, including nitrate, nitrite, cadmium, lead, and chromium, are below the established safe thresholds for consumption. Our results provide valuable information for the sustainable utilization of S. alterniflora resources and will contribute to the integrated control of S. alterniflora. Full article

Sustainable crop production requires an innovative approach due to increasing soil salinisation and decreasing freshwater availability. One promising strategy is the domestication of naturally salt-tolerant plant species with commercial potential. Sarcocornia fruticosa is a highly salt-tolerant halophyte, common in Mediterranean marshes, which may hold promise for biosaline agriculture. This study included 11 populations of this species spread over the territory of the Valencian Community in eastern Spain. Climatic data for each locality were obtained from the nearest meteorological stations. Soil analyses included texture, pH, electroconductivity, organic carbon and organic matter. Biochemical analyses on wild-sampled plant material focused on antioxidant compounds, such as carotenoids, phenolics, flavonoids and proline with malondialdehyde (MDA) used as a marker of oxidative stress. All variables (climatic, edaphic and biochemical) were evaluated together using Principal Component Analysis and Spearman correlation. The results obtained indicated some climatic differences in terms of mean annual precipitation, with a clear N-S gradient and considerable edaphic variability. However, none of the environmental conditions showed a clear correlation with plant biochemical characteristics. Significant differences in the levels of phenolic compounds, flavonoids and MDA between populations were probably due to genetic factors and cannot be explained as a response to environmental conditions. Full article

Salt-sensitive trees in coastal wetlands are dying as forests transition to marsh and open water at a rapid pace. Forested wetlands are experiencing repeated saltwater exposure due to the frequency and severity of climatic events, sea-level rise, and human infrastructure expansion. Understanding the diverse responses of trees to saltwater exposure can help identify taxa that may provide early warning signals of salinity stress in forests at broader scales. To isolate the impacts of saltwater exposure on trees, we performed an experiment to investigate the leaf-level physiology of six tree species when exposed to oligohaline and mesohaline treatments. We found that species exposed to 3–6 parts per thousand (ppt) salinity had idiosyncratic responses of plant performance that were species-specific. Saltwater exposure impacted leaf photochemistry and caused early senescence in Acer rubrum, the most salt-sensitive species tested, but did not cause any impacts on plant water use in treatments with <6 ppt. Interestingly, leaf spectral reflectance was correlated with the operating efficiency of photosystem II (PSII) photochemistry in A. rubrum leaves before leaf physiological processes were impacted by salinity treatments. Our results suggest that the timing and frequency of saltwater intrusion events are likely to be more detrimental to wetland tree performance than salinity concentrations. Full article

The presence of anthropogenic compounds, including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), was studied in three salt marshes within the Tagus estuary, Portugal, along an anthropogenic pressure gradient. Results revealed differences in OCPs and PCBs among the marshes, with differing concentration levels. Specifically, one marsh, with surrounding agricultural activity, showed the highest OCP concentrations, while another, with a historical industrial past, exhibited elevated PCB levels. In contrast, a third marsh, part of a natural reserve, displayed comparatively lower concentrations of both substances. Sediment concentrations, likely influenced by agricultural practices, were found to be comparable to or higher than those observed in other Portuguese estuaries. The halophyte Spartina maritima was found to absorb OCPs, particularly in its aboveground tissues, suggesting bioaccumulation within the plant. Additionally, PCB levels appeared to be influenced by industrial history, with one marsh displaying notably higher concentrations. In conclusion, the persistence of organochlorine compounds in the salt marsh ecosystems notwithstanding the regulatory prohibitions implemented in the 1990s highlights the need for continuous monitoring and study of such sites and the necessity of remediation practices, which are imperative to mitigate ecological and health risks in these polluted salt marshes. Full article

Tidal wetlands, commonly known as salt marshes, are highly productive ecosystems in temperate regions worldwide. These environments constitute a unique flora composed primarily of salt-tolerant herbs, grasses, and shrubs. This study investigated the therapeutic properties of ten salt marsh plants collected mainly from Palk Bay and Mannar Gulf against Candida disease. This study examined the changes in natural plant products associated with their anti-Candida growth activity during two distinct seasonal changes—monsoon and summer. The potential of the salt marshes to inhibit the growth of five different Candida strains was assessed using four solvents. In phytochemical analysis, the extracts obtained from a Launaea sarmentosa exhibited the highest results compared to the other plant extracts. Fourier transform infrared spectroscopy revealed 12 peaks with alkane, aldehyde, amine, aromatic ester, phenol, secondary alcohol, and 1,2,3,4-tetrasubstituted. Gas-chromatography–mass spectrometry detected 30 compounds. Cyclotetracosane, lupeol, β-amyrin, and 12-oleanen-3-yl acetate showed the highest peak range. In particular, plant samples collected during the monsoon season were more effective in preventing Canda growth than the summer plant samples. In the monsoon season, the salt marsh plant extracted with ethyl acetate showed a high anti-Candida growth activity, while in the summer, the acetone extract exhibited a higher anti-Candida growth activity than the other solvents. The hexane extract of L. sarmentosa showed the highest inhibition zone against all Candidal strains. Furthermore, compounds, such as β-amyrin, lupeol, and oxirane, from the hexane extract of L. sarmentosa play a vital role in anti-Candida activity. This paper reports the potential of tidal marsh plant extracts for developing new antifungal agents for Candida infections. Full article

Salt marshes are highly dynamic and biologically diverse ecosystems that serve as natural habitats for numerous salt-tolerant plants (halophytes). We investigated the bacterial communities associated with the roots and leaves of plants growing in the coastal salt marshes of the Bayfront Beach, located in Mobile, Alabama, United States. We compared external (epiphytic) and internal (endophytic) communities of both leaf and root plant organs. Using 16S rDNA amplicon sequencing methods, we identified 10 bacterial phyla and 59 different amplicon sequence variants (ASVs) at the genus level. Bacterial strains belonging to the phyla Proteobacteria, Bacteroidetes, and Firmicutes were highly abundant in both leaf and root samples. At the genus level, sequences of the genus Pseudomonas were common across all four sample types, with the highest abundance found in the leaf endophytic community. Additionally, Pantoea was found to be dominant in leaf tissue compared to roots. Our study revealed that plant habitat (internal vs. external for leaves and roots) was a determinant of the bacterial community structure. Co-occurrence network analyses enabled us to discern the intricate characteristics of bacterial taxa. Our network analysis revealed varied levels of ASV complexity in the epiphytic networks of roots and leaves compared to the endophytic networks. Overall, this study advances our understanding of the intricate composition of the bacterial microbiota in habitats (epiphytic and endophytic) and organs (leaf and root) of coastal salt marsh plants and suggests that plants might recruit habitat- and organ-specific bacteria to enhance their tolerance to salt stress. Full article

Salt marsh grass (Sporobolus alterniflorus) plays a crucial role in Delaware coastal regions by serving as a physical barrier between land and water along the inland bays and beaches. This vegetation helps to stabilize the shoreline and prevent erosion, protecting the land from the powerful forces of the waves and tides. In addition to providing a physical barrier, salt marsh grass is responsible for filtering nutrients in the water, offering an environment for aquatic species and presenting a focal point of study for high salt tolerance in plants. As seawater concentrations vary along the Delaware coast from low to medium to high salinity, our study seeks to identify the impact of salt tolerance in marsh grass and to identify genes associated with salt tolerance levels. We developed more than 211,000 next-generation-sequencing (Illumina) transcriptomic reads to create a reference transcriptome from low-, medium-, and high-salinity marsh grass leaf samples collected from the Delaware coastline. Contiguous sequences were annotated based on a homology search using BLASTX against rice (Oryza sativa), foxtail millet (Setaria italica), and non-redundant species within the Viridiplantae database. Additionally, we identified differentially expressed genes related to salinity stress as candidates for salt stress qPCR analysis. The data generated from this study may help to elucidate the genetic signatures and physiological responses of plants to salinity stress, thereby offering valuable insight into the use of innovative approaches for gene expression studies in crops that are less salt tolerant. Full article