Wetland Research Articles

Comparative metagenomics reveals the metabolic flexibility of coastal prokaryotic microbiomes contributing to lignin degradation

Coastal wetlands are rich in terrestrial organic carbon. Recent studies suggest that microbial consortia play a role in lignin degradation in coastal wetlands, where lignin turnover rates are likely underestimated. However, the metabolic potentials of these consortia remain elusive. This greatly hinders our understanding of the global carbon cycle and the “bottom-up” design of synthetic consortia to enhance lignin conversion. Here, we developed two groups of lignin degrading consortia, L6 and L18, through the 6- and 18-month in situ lignin enrichments in the coastal East China Sea, respectively. Lignin degradation by L18 was 3.6-fold higher than L6. Using read-based analysis, 16S rRNA amplicon and metagenomic sequencing suggested that these consortia possessed varied taxonomic compositions, yet similar functional traits. Further comparative metagenomic analysis, based on metagenomic assembly, revealed that L18 harbored abundant metagenome-assembled genomes (MAGs) that encoded diverse and unique lignin degradation gene clusters (LDGCs). Importantly, anaerobic MAGs were significantly enriched in L18, highlighting the role of anaerobic lignin degradation. Furthermore, the generalist taxa, which possess metabolic flexibility, increased during the extended enrichment period, indicating the advantage of generalists in adapting to heterogenous resources. This study advances our understanding of the metabolic strategies of coastal prokaryotic consortia and lays a foundation for the design of synthetic communities for sustainable lignocellulose biorefining.

Will Olive Groves have a Future Under Climate Change Conditions in The North Aegean Sub-Region, a Mediterranean Agricultural Ecosystem of Türkiye?

The study is aimed at investigating future changes in sustainability of olive farming by means of climate change, and changes in agricultural climatic suitableness and phenology of olive tree cultivation in the North Aegean sub-region of Türkiye mainly characterised with dry summer subtropical Mediterranean climate. According to projected changes based on RCP8.5 scenario, projected warming reaches an average of 5-6°C increase indicating most negative condition on olive cultivation. According to RCP8.5 scenario annual precipitation projections, present suitable areas of olive groves will decrease in the period of 2049-2073, and almost the entire study area will be in the category of medium suitable. With respect to projected Emberger Bioclimate classification, for RCP 8.5 scenario, there will be a significant increase in dry-sub humid areas in the period of 2049-2073. This increase will cover up the coastal areas in the period of 2074-2098, and even all the study region will be very likely characterised with dry-sub humid and semi-arid Mediterranean bioclimatic types except for some coastal areas. An increase of about 6°C is expected in maximum values of maximum air temperatures during the bud swelling periods in the spring, especially after 2050 under RCP8.5 scenario. This increase in extreme maximum temperatures may cause olive trees to bloom earlier and prolong the growth period. By regarding the high vernalization requirement of main olive variety in the study area, a 6°C temperature increase may significantly decrease olive yields and will force farmers to transition to new varieties with relatively low vernalization requirements. According to both RCP scenarios, there is a possibility of extension of suitable areas for olive cultivation towards low to mid-elevation plateaus and mid-elevation slopes of mountainous areas and high plateaus particularly facing suitable aspects to lower negative effects of projected future warming and dryness.

Exploration and Empirical Study on Spatial Distribution of SOC at the Core Area in Coastal Tamarix Forests’ Inland Side of Changyi National Marine Ecological Area

The forest soil carbon pool plays a vital role in terrestrial ecosystems, being of great significance for maintaining global balance, regulating the global carbon cycle, and facilitating ecological restoration. Shandong Changyi Marine Ecological Special Protection Area is the only state-level marine special protection area in China with tamarisk as the main object of protection, and it is the largest continuous and the best preserved natural tamarisk forest distribution area on the mainland coast of China. Compared to other forested areas, research on the spatial distribution of SOC at the core area in coastal Tamarix forests’ inland side appears to be relatively scarce. Based on this, this paper takes the core area of the Changyi National Marine Ecological Special Protection Zone, located on the southern coast of Laizhou Bay, as the research subject, based on the potassium dichromate oxidation-external heating, one-way ANOVA, and Bonferroni methods, analyzing the spatial distribution of the SOC content inland of coastal Tamarix forests. The research yielded the following conclusions: (1) The surface layer (0–10 cm) contributes significantly to the total SOC content within a 0–60 cm depth, accounting for at least 31% and shows notable surface accumulation. (2) The combined SOC content in the surface and subsurface layers (10–20 cm) accounts for at least 50% of the total SOC content within a 0–60 cm depth, indicating the dominance of these two soil layers in carbon storage. (3) The SOC content decreases with the soil depth at all six sampling points within the 0–60 cm range, with a marked drop from 0–10 cm to 10–20 cm. (4) One-way ANOVA and multiple comparisons reveal that the soil depth significantly affects the SOC distribution, particularly between the surface and 20–30 cm layers (p < 0.001), indicating high robustness and statistical significance. (5) Horizontally, the total SOC at 0 m is 45% lower than at 2 m in the 0–60 cm layer. The SOC in the 0–20 cm layer fluctuates significantly with distance from the shrub trunk, while the SOC in the 30–60 cm layers is low and stable, with minimal variations with depth. In addition, this study found that the SOC content in the core area of the protected area is lower than that in the common forest ecosystem. In the future, scientific ecological restoration projects and management protection methods should be used to improve soil’s carbon storage and carbon sink capacity. These findings not only validate the patterns of SOC’s spatial distribution in coastal Tamarix forest wetlands but also provide a scientific basis for carbon assessment and the formulation of ecological protection measures in coastal wetlands.

Rapid radiation of a plant lineage sheds light on the assembly of dry valley biomes.

Southwest China is characterized by high plateaus, large mountain systems, and deeply incised dry valleys formed by major rivers and their tributaries. Despite the considerable attention given to alpine plant radiations in this region, the timing and mode of diversification of the numerous dry valley plant lineages remain unknown. To address this knowledge gap, we investigated the macroevolution of Isodon (Lamiaceae), a lineage commonly distributed in the dry valleys in southwest China and wetter areas of Asia and Africa. We reconstructed a robust phylogeny encompassing nearly 90% of the approximately 140 extant Isodon species using transcriptome and genome-resequencing data. Our results suggest a rapid radiation of Isodon during the Pliocene that coincided with a habit shift from herbs to shrubs and a habitat shift from humid areas to dry valleys. The shrubby growth form likely acted as a preadaptation allowing for the movement of Isodon species into these dry valleys. Ecological analyses highlight drought-related factors as key drivers influencing the niche preferences of different growth forms and species richness of Isodon. The interplay between topography and the development of the East Asian monsoon since the middle Miocene likely contributed to the formation of the dry valley biome in southwest China. This study enhances our understanding of evolutionary dynamics and ecological drivers shaping the distinctive flora of southwest China and reveals the strategies employed by montane plants in response to climate change and dryland expansion, thus facilitating conservation efforts globally.

Relative forces of anthropogenic and natural factors on the evolution of "ecological cancer"-rocky desertification under different man-land relationships.

Rocky desertification (RD) is a severe phenomenon in karst areas, often referred to as "ecological cancer." However, studies on RD rarely include comparative analysis of different man-land relationship areas. This lack of analysis leads to difficulties in preventing and controlling RD in local areas with complex man-land relationships. To address this issue, we selected two typical karst areas, Guangnan County (with subtropical humid and agricultural peak-valley area) and Yulong County (with temperate semi-arid and ecological tourism alpine-canyon area), as comparative research areas. We analyzed the evolution of RD in these two typical areas and revealed the relative forces of anthropogenic and natural factors on RD at both a single and comprehensive level by using the geographical detector and the coupled principal component-structural equation model. The study found that (1) the RD in Yulong County was more severe than that in Guangnan County. From 2010 to 2020, RD in both counties showed a positive succession trends. The RD has a high degree of spatial fragmentation, and spatial evolution usually occurs in areas where the man-land relationship is complex. (2) In terms of single factor, the RD in the two counties was mainly affected by anthropogenic factors such as control, farming, behavioral disturbance, and social economy, and natural factors such as geology, soil, topography, and surface state. (3) Comprehensive effects show that forces of anthropogenic vs natural factors on formation/evolution of RD are different between Guangnan County (0.36 for anthropogenic factor vs -0.64 for natural factor) and Yulong County (higher with anthropogenic: 0.44 vs natural: 0.89). (4) Differentiated strategies should be adopted due to role played by anthropogenic and natural factors across different man-land relationship areas to explore suitable control measures for RD. The research creates a scientific basis for the control of RD, ecological restoration, and sustainable development in various regions. It can also be utilized as a valuable reference for comparative analysis of similar geographical phenomena.

Coastal wetland resilience through local, regional and global conservation

Coastal wetland resilience through local, regional and global conservation

Root productivity contributes to carbon storage and surface elevation adjustments in coastal wetlands

Abstract Background and aims Organic matter additions in coastal wetlands contribute to blue carbon sequestration and adjustment to sea-level rise through vertical substrate growth, with accurate modelling of these dynamics requiring information of root mass and volume additions across tidal gradients. This study aims to characterise the influence of vegetation zonation and tidal position on root mass and volume dynamics within substrates. Methods The root ingrowth technique was coupled with sediment cores to quantify below-ground root mass and volume production, standing stocks and turnover across two years to 90 cm depth at Kooweerup, Victoria, Australia. Results We indicate a complex non-linear relationship between fine root mass production and tidal position, influenced by variable vegetation structures across mangrove (442–3427 g m−2 yr−1), saltmarsh (540–860 g m−2 yr−1) and supratidal forest (599 g m−2 yr−1) zones. Fine root volume additions ranged from 274 to 4055 cm3 m−2 yr−1 across sampling locations. Root production was greatest for older mangroves and tidally defined optimal zones of production were evident for mangrove and saltmarsh. Live roots extended deeper than typically studied, reaching depths of 1.0 m in forested zones. Conclusion This information of root mass and volume additions across wetland live rooting zones can be used to improve highly parameterised models accounting for carbon sequestration and substrate vertical adjustment along intertidal gradients. We recommend that future studies measure root production across the entire active rooting zone or to 1 m depth to align with standard carbon accounting measurement depths.

Nineteenth-century land use shapes the current occurrence of some plant species, but weakly affects the richness and total composition of Central European grasslands

ContextHistorical land use is thought to have influenced plant community diversity, composition and function through the local persistence of taxa that reflect ecological conditions of the past.ObjectivesWe tested for the effects of historical land use on contemporary plant species richness, composition, and ecological preferences in the grassland vegetation of Central Europe.MethodsWe analyzed 6975 vegetation plots sampled between 1946 and 2021 in dry, mesic, and wet grasslands in the borderland between Austria, the Czech Republic, and Slovakia. Using 1819–1853 military maps, we assigned each plot to a historical land-use category (arable land, forest, grassland, settlement, permanent crop, and water body). We modeled the response of species richness, composition, and plant ecological preferences to the historical land use including contemporary covariates.ResultsNineteenth-century land use explained little overall variation in species richness and composition, whereas more variation was explained by contemporary environmental conditions. However, we found that ecological preferences of some species were associated with specific historical land uses. Specifically, species more frequently occurring in historically forested grasslands showed lower light and disturbance frequency indicator values, while those associated with former settlements displayed higher disturbance severity indicator values.ConclusionsWe conclude that signatures of specific land-use conversions, including the restoration of grasslands in human-impacted areas, may still be detectable in grasslands even 200 years into the future. However, while local historical land use influences the occurrence of some species based on their ecological preferences, these effects do not significantly influence community species richness and total composition.

Evaluation of Risk Factors Influencing Tick-Borne Infections in Livestock Through Molecular Analyses

Climate changes and human-related activities are identified as major factors responsible for the increasing distribution and abundance of vectors worldwide and, consequently, of vector-borne diseases (VBDs). Farmed animals, during grazing or in establishments with the absence of biosecurity measures, can easily be exposed to wildlife showing high-risk of contagion of several infectious diseases, including VBDs. Furthermore, livestock represents an interface between wildlife and humans, and thus, promoting the transmission pathway of VBDs. Little is known about the presence and prevalence of VBDs in livestock in Southern Italy; therefore, the present study evaluated the circulation of zoonotic VBDs in livestock and potential risk of exposure. A total of 621 whole blood samples belonging to cattle and buffaloes (n = 345) and small ruminants (n = 276) were examined by molecular examinations for the detection of tick-borne pathogens (TBPs). High prevalence (66.3%) for at least one agent was observed. Moreover, the risk of exposure related to environmental features was assessed, as follows: presence of humid areas, high-density of animals, and sample collection during May. These results show a high circulation of TBPs among livestock and underline the need for surveillance in high-risk habitats for public health.

Glasswort as a Strategic Crop in Coastal Wetlands: Intercropping Results with Swiss Chard

The Mediterranean region is experiencing severe droughts and unprecedented high temperatures. In terms of salinity, about 18 million ha of land, or 25% of the total irrigated area in the Mediterranean, is salt affected. The use of halophytes as intercropping species to mitigate the effects of salt stress is attractive. Halophytes have a great capacity to maintain their productivity in this extreme environment, thus supporting climate-appropriate agriculture. The aim of this study was to evaluate the productivity of Salicornia europaea L. subsp. ramosissima (glasswort) under field conditions and high soil salinity, grown as a sole crop (monocropping) and as a companion crop (intercropping) with Beta vulgaris L. subsp. cicla (Swiss chard) in a 1:1 cropping pattern. The field trials were conducted in the coastal wetland “King’s Lagoon”, a private nature reserve in the Apulia/Puglia region (southern Italy), during two consecutive spring–summer seasons in 2023 and 2024 and under different management conditions of irrigation and fertilization. These were performed to test for possible interaction effects. The results showed that both glasswort and chard can be grown sustainably under slightly saline conditions (ECe range 4–8 dS m−1). In contrast, strongly saline conditions (ECe > 16 dS m−1) were prohibitive for chard, both as a sole crop and as an intercrop, but were largely beneficial for glasswort. Swiss chard can benefit from intercropping with glasswort when soil salinity is still tolerable (6.9 dS m−1), showing an LER (Land Equivalent Ratio) ≥ 1.19. Meanwhile, glasswort did not significantly improve the growth of the companion crop (Swiss chard) when the soil was considerably saline (16.6 dS m−1). Higher LER values were observed when the contribution of chard to the intercrop performance was significantly greater than that of glasswort, i.e., under slightly saline conditions. This means that glasswort can have a significant positive effect on chard growth and productivity as long as soil is still moderately saline. Glasswort can therefore be considered a valuable model crop in extreme environments. The integration of glasswort (possibly together with other local halophytes) into diversified cropping systems on saline marginal soils is a promising sustainable agricultural practice in environmentally fragile areas such as wetlands, swamps, brackish areas, and marshes.

Characteristics of Spatial and Temporal Evolution of Coastal Wetland Landscape Patterns and Prediction Analysis—A Case Study of Panjin Wetland, China

Characteristics of Spatial and Temporal Evolution of Coastal Wetland Landscape Patterns and Prediction Analysis—A Case Study of Panjin Wetland, China

Estimating soil organic carbon using UAV and Sentinel-2 images and multilayer perceptron regression in Coastal Wetland

ABSTRACT Hyperspectral imagery from an Unmanned Aerial Vehicle (UAV) has been used to predict soil organic carbon (SOC) content. This study compared UAV hyperspectral imagery with Sentinel-2A multispectral imagery and soil spectra in the laboratory to predict the SOC content in Suaeda salsa (S. salsa) coastal wetland. Characteristic variables were determined through correlation analysis comparing observed SOC with constructed spectral indices of SOC, index variables, and spectral bands. Predict Models of SOC were constructed by multilayer perceptron (MLP), the prediction accuracy was evaluated and the spatial maps of SOC were produced. The results showed that estimating SOC using UAV, Sentinel imagery, and laboratory spectra has great potential when using MLP algorithm. The SOC content can be accurately predicted by the laboratory spectra without spatial map. The accuracy of SOC estimation was better when based on Sentinel-2A imagery than UAV imagery, with the model determination coefficients (R 2) of 0.838 and 0.638, the root mean square error (RMSE) of 0.398 and 0.596 g kg−1, ratio of performance to deviations (RPD) of 2.485 and 1.660, and bias of − 0.028 and 0.085 g kg−1, respectively. The SOC estimation model using Sentinel-2A imagery demonstrated better stability than that using UAV imagery, with the mean uncertainty standard deviations (SD) of 0.226 and 0.291 g kg−1, respectively. The spatial SOC maps generated from both UAV and Sentinel-2A imagery presented more subtle variation information when compared with the spatial interpolation results. Although the prediction accuracy of SOC from UAV was lower than that from Sentinel-2A, UAV imagery could disclose more fine distribution information of SOC at the local level. The UAV imagery can be used to estimate SOC in coastal wetlands but with a higher cost than freely available Sentinel images. We recommend using sentinel imagery to predict SOC at regional, national, or even global levels.

Population dynamics and the role of protected areas in China’s milu deer (Elaphurus davidianus) rewilding

Protected areas are refugia for wildlife and play a crucial role in biodiversity conservation, especially in the restoration of rare and endangered species. However, little attention has been paid to the long-term contribution of protected areas to rare species population rejuvenation. To identify the population growth of milu deer (Elaphurus davidianus)in protected areas and unprotected areas, we fitted the population dynamics curve of reintroduced free-ranging and wild populations based on long-term monitoring data in four protected areas: Jiangsu Dafeng Milu National Nature Reserve, Hubei Shishou Milu National Nature Reserve, Hunan East Dongting Lake National Nature Reserve, and Jiangxi Poyang Lake area. We also examined population dynamics in two unprotected areas: Yangbotan wetland and Sanheyuan wetland in Shishou County, Hubei province. We analyzed the habitat characteristics (coastal marshy wetland, riverine wetlands, and lake wetlands)in all these areas. The results showed that: (1) population growth in Dafeng, Shishou, Dongting, Sanheyuan and Yangbotan all followed an S-curve (p < 0.001); while population growth around Poyang Lake was linear (p < 0.001); (2) the population growth rate of Yangbotan wetland was significantly higher than that of Dongting Nature Reserve (p < 0.05); and (3) the two unprotected areas, Yangbotan and Sanheyuan wetlands, are important for the conservation of milu, as they have been facing the threats of urbanization and fragmentation in recent years. Our studies indicate that long-term conservation in protected areas has played an irreplaceable role in the reconstruction and rejuvenation of wild populations of milu deer over the past 30 years, and multiple reintroductions are an effective way to quickly restore wild milu populations in China.

Ensemble habitat suitability model predicts Suaeda salsa distribution and resilience to extreme climate events.

Climate anomalies lead to an increased occurrence of extreme temperature and drought events in coastal wetlands, resulting in heightened survival pressure on salt marsh plants. It is imperative to anticipate the effects of these events on the habitat suitability and resilience of coastal salt marsh vegetation to inform restoration efforts and management strategies. Herein, an ensemble model was developed to evaluate the recovery of Suaeda Salsa in the two subsequent years following the anomalously high temperatures and decreased precipitation experienced during the summer of 2018, potentially leading to a decline in this species in the eastern coast of Liaohe Estuary wetland (Bohai Sea, China). Additionally, the resilience of the ecosystem was evaluated based on the evolution of density and morphology metrics of S. salsa. The findings suggest that the ensemble model demonstrates exceptional predictive performance in assessing habitat suitability, as evidenced by True Skill Statistic (TSS) values of 0.94±0.02 and 0.96±0.03 for the years 2019 and 2020, respectively, and Area Under the Receiver Operating Characteristic Curve (AUC) values of 0.96±0.03 in 2019 and 0.97±0.02 in 2020. Tidal elevation and soil salinity were identified as the primary predictors for the habitat suitability of S. salsa, while sand content emerged as the most influential factor driving its expansion. The core and suitable habitat areas of S. salsa experienced a significant increase from 9.61±1.16km2 in 2019 to 15.66±2.24km2 in 2020, representing a 62.96±8.44 % growth. A notable increase in density and above-ground biomass was noted, indicating a potential recovery of salt marsh vegetation from multi-stresses. However, a decline in below-ground biomass, from 61.9gm-2 in August 2018 to 39.8gm-2 in August 2020, suggests a reduction in the resilience of S. salsa to future disturbances. This decrease in below-ground reserves, which were crucial for the tolerance of S. Salsa, may impact the vegetation's ability to withstand future challenges. The results highlight the effectiveness of optimizing freshwater irrigation and implementing artificially constructed tidal channels as strategies for future restoration efforts. Besides, the evaluation method of habitat suitability and bio-metrics proposed herein is applicable to the restoration and protection for other estuarine halophytes.

Balancing methane emission and alkalinity conservation: Insights from mineral amendments in coastal sediments.

With global climate warming and ocean acidification, mineral amendments in coastal areas have emerged as a promising strategy to bolster carbon sinks and alkalinity. However, most research has predominantly focused on carbon dioxide (CO2) absorption, with limited exploration of methane (CH4) reduction despite its more potent greenhouse effect. To address this gap, our study conducted a microcosm manipulative experiment employing coastal wetlands sediments to elucidate the regulatory effects of various mineral amendments on greenhouse gas emissions (including CO2 and CH4) and seawater alkalinity. The findings unveiled that olivine application effectively absorbed CO2, achieving a 175% reduction (-342.0mmolL-1h-1) in the late stage, while gypsum application significantly reduced CH4 by 53% (-6.06mmolL-1h-1) in the early stage. Nevertheless, applying gypsum led to a marked decrease in seawater alkalinity, potentially exacerbating ocean acidification and posing risks to marine ecosystems. Interestingly, the simultaneous application of both minerals showed promise in reducing CH4 emissions without compromising seawater alkalinity. This study presents a pioneering endeavor that contributes to the sustainable management of coastal wetlands and supports future initiatives at reducing CH4 emissions and alleviating ocean acidification.

Increased Mineral-Associated Organic Carbon and Persistent Molecules in Allochthonous Blue Carbon Ecosystems.

Coastal wetlands contain very large carbon (C) stocks-termed as blue C-and their management has emerged as a promising nature-based solution for climate adaptation and mitigation. The interactions among sources, pools, and molecular compositions of soil organic C (SOC) within blue C ecosystems (BCEs) remain elusive. Here, we explore these interactions along an 18,000 km long coastal line of salt marshes, mangroves, and seagrasses in China. We found that mineral-associated organic C (MAOC) is enriched in BCEs dominated by allochthonous inputs and abundant active minerals, leading to an increased proportion of persistent organic molecules. Specifically, soils with large allochthonous inputs (> 50%) are characterized by a substantial contribution of MAOC (> 70%) to total SOC with a notable preservation of lipids (36%) across salt marshes, mangroves, and seagrasses. The burial of allochthonous particles, derived from external sources such as rivers or tidal influxes, facilitates the formation of stable MAOC through binding to mineral surfaces or occlusion within microaggregates. The proportions of particulate organic C (POC) and MAOC are important predictors for molecular compositions of soil organic matter. Lipid proportions within molecular composition decrease as POC and autochthonous C proportions increase. These findings provide new insights into the coupled control over SOC sequestration in BCEs, emphasizing the role of allochthonous inputs, proportions of carbon pools, and persistent organic components.

Removal and ecological impact of sulfamethoxazole and N-acetyl sulfamethoxazole in mesocosmic wetlands dominated by submerged plants: Plant tolerance, microbial response, and nitrogen transformation.

Sulfamethoxazole (SMX) and its human metabolite N-acetylsulfamethoxazole (N-SMX) are frequently detected in aquatic environments, posing potential threats to freshwater ecosystem health. Constructed wetlands are pivotal for wastewater treatment, with plant species serving as key determinants of pollutant removal efficiency. In this study, wetlands dominated by three submerged plants (Myriophyllum verticillatum, Vallisneria spiralis, Hydrilla verticillata) were respectively constructed to investigate the removal of SMX and N-SMX, and the impact on wetland ecology regarding plant tolerance, microbial response, and nitrogen transformation. Results showed that wetlands removed N-SMX (82.3-99.8%) more effectively than SMX (54.3-80.2%), with the wetland dominated by Myriophyllum verticillatum showing the highest removal efficiency. However, high concentrations (5mg/L) of SMX and N-SMX significantly reduced NH4+-N and TN removal (p<0.05), accompanied by shifts in microbial communities, especially a decreased abundance of Proteobacteria and key nitrogen-transforming genes. A total of 22 different ARGs (antibiotic resistance genes) were detected. SMX significantly increased the relative abundance of sulfonamide resistance genes (sul1, sul2) (p<0.05), while major denitrifying genera, such as Thiobacillus, which were not the primary hosts of these genes, showed a significant negative correlation with sul1 and sul2 (p<0.05). This study provides a reference for ecological remediation of wetlands in response to antibiotic contamination.

Drimane-type sesquiterpenoids and triterpenoids from the whole plant of Limonium sinense with their antiproliferative and anti-inflammatory activities.

Saline-tolerant medicinal plants possess novel chemical constituents with high bioactivity because of their unique secondary metabolic pathways. Limonium sinense, an aquatic plant found in the coastal wetlands of the Yellow River Delta, was collected and studied in the present work. Ten drimane-type sesquiterpenoids and four triterpenoids, including six new ones (sinenseines A-F), were isolated from a whole plant of L. sinense for the first time. Their structures, including the absolute configurations, were determined by analyzing the comprehensive spectroscopic data. In addition, twelve terpenoids, including nine sesquiterpenoids, were identified using UPLC-MS/MS and GNPS methods. All isolates were evaluated for their antiproliferative and anti-inflammatory activities. Compounds 2-4, 6, 13, and 14 showed moderate anti-tumor effects on A549, H1299, HepG2 and A2780 cells with IC50 values ranging from 35.2 ± 2.0 to 90.5 ± 3.1 μM. Furthermore, compound 1 exhibited significant anti-inflammatory activity with an IC50 value of 8.3 ± 1.2 μM against NO production in LPS-induced RAW 264.7 macrophages.

Developing a new index with time series Sentinel-2 for accurate tidal flats mapping in China.

Tidal flats are essential habitats for a wide variety of plants and animals along the coast, contributing significantly to biodiversity preservation. Despite efforts to employ remote sensing technology for mapping these areas, misidentification remains a persistent issue. Within the context of tidal flat mapping, one of the primary challenges lies in distinguishing between tidal flats and turbid water bodies. This is primarily attributed to the high sediment content in turbid water bodies, which renders their spectral characteristics similar to those of tidal flats, consequently leading to confusion. To this end, this study developed a novel Tidal Flats-Water Difference Index (TWDI) with time series Sentinel-2 to accurately map tidal flats in China for the year 2020. The index demonstrates robust performance in distinguishing between tidal flats and water bodies, particularly in turbid water conditions. It reduces the likelihood of misclassifying water bodies as tidal flats, thus enhancing the accuracy of tidal flats mapping. Based on this index, we generated Tidal Flats Map of China at 10m (TFMC) in 2020 based on the GEE. With validation from 10,234 samples, the TFMC map attained an overall accuracy (OA) and F1 score of 0.97. Based on our calculations, the total area of tidal flats in China was 9195.80km2, with Jiangsu Province accounting the largest area at the provincial level (2467.71km2). This study is the first attempt to address the issue of misclassification of turbid water bodies as tidal flats. TWDI can serve as the spectral index in tidal flats mapping or as input features for training classification models of coastal wetland. The TFMC map can serve as foundational data to promote the protection of tidal flats and the sustainable development of coastal wetland ecosystems.

Waterbird diversity and its influencing factors in various types of coastal wetlands in the Bohai Rim region

Waterbird diversity and its influencing factors in various types of coastal wetlands in the Bohai Rim region