Wetland Research Articles

Effects of High Salinity and Water Stress on Wetland Grasses from the Spanish Mediterranean Coast.

The impacts of climate change are reaching unprecedented levels, heightening the risk of species loss and ecosystem service degradation. Wetlands, highly threatened ecosystems, serve vital ecological functions by capturing carbon, filtering water, and harbouring diverse wildlife. Coastal wetlands encounter many challenges, such as increased drought periods and escalating salinity levels, severely impacting plant biodiversity. Assessing how plants respond to various environmental stress factors is imperative for devising successful conservation strategies. In the present study, we examined three representative grass species found in various habitats within the Albufera Natural Park, close to the city of Valencia on the Spanish Mediterranean coast: Imperata cylindrica, Phragmites australis, and Saccharum ravennae. High salinity and water stress conditions were induced by subjecting the plants to irrigation with solutions containing 200, 400, 600, and 800 mM NaCl or withholding irrigation altogether to mimic coastal flooding and drought scenarios. The treatments were maintained until noticeable wilting of the plants occurred, at which point a range of stress biomarkers were determined, including photosynthetic pigments, ions, osmolytes, oxidative stress markers, and antioxidant metabolites, as well as antioxidant enzyme activities. Saccharum ravennae displayed the highest sensitivity to salt stress, whereas I. cylindrica appeared to be the most tolerant. The primary salinity tolerance mechanism observed in I. cylindrica and P. australis was a blockage of ion transport from the root zone to the aerial part, together with the salt-induced accumulation of proline and soluble sugars to high concentrations in the former. No significant effects of the water deficit treatment on the growth or biochemical parameters were observed for any of the analysed species. These findings offer valuable information for the effective management and conservation of coastal wetlands facing the challenges posed by climate change.

Effects of Vegetation Restoration Age on Soil C: N: P Stoichiometry in Yellow River Delta Coastal Wetland of China

Effects of Vegetation Restoration Age on Soil C: N: P Stoichiometry in Yellow River Delta Coastal Wetland of China

Seasonal variations in drag coefficient of salt marsh vegetation

Understanding the seasonal variations of vegetation drag coefficients is crucial for improving wave attenuation predictions and adapting to climate impacts. This study explores the seasonal changes in drag coefficients within salt marsh vegetation, using data from a year-long series of field measurements at the Chongming Dongtan Wetland. It uncovers the complex seasonal variations of drag coefficients. Results demonstrate that incorporating a nonlinear equation for characteristic flow velocity and effective vegetation length significantly improves the precision of drag coefficient predictions, ensuring a closer match with field observations. Furthermore, it introduces a refined drag coefficient formula that incorporates adjustments for vegetation stiffness and relative submergence, offering a more accurate representation of the seasonal variability in drag forces exerted by salt marsh vegetation. This enhanced formula is crucial for accurately assessing vegetation's role in wave attenuation, providing critical insights for the design and implementation of coastal defense and wetland conservation initiatives.

Contamination status, source analysis and exposure assessments of quinolone antibiotics in the south of Yancheng Coastal Wetland, China.

Yancheng coastal wetland, the largest coastal wetland in the west coast of the Pacific Ocean and the margin of the Asian continent, has significant environmental, economic and social effects on local human beings. The extensive contamination and potential risk of quinolone antibiotics (QNs) on local aquaculture and human health are still not clear until now. In this study, 52 surface sediment samples were collected to investigate the contamination status and polluted sources, and evaluate ecological risks of QNs in the south of Yancheng coastal wetland. The total contents of QNs ranged from 0.33 to 21.60ng/g dw (mean value of 4.51ng/g dw), following the detection frequencies of QNs ranging from 19.23 to 94.23%. The highest content of QNs occurred around an aquaculture pond dominated by flumequine. The total organic carbon contents of sediment were positively correlated with sarafloxacin and lomefloxacin (p < 0.05), indicating the enhanced absorption of these QNs onto sediments. Partial QNs, such as lomefloxacin, enrofloxacin, sarafloxacin and flumequine, presented the homology features originating from the emission of medical treatment and aquaculture. There was no potential risk of QNs to human beings but a potential risk to aquatic organisms (algae > plant > invertebrate). Totally, the management and protection of Yancheng coastal wetland should be of concern with aquaculture as the important industry.

Rising seas could cross thresholds for initiating coastal wetland drowning within decades across much of the United States

Accelerated sea-level rise is an existential threat to coastal wetlands, but the timing and extent of wetland drowning are debated. Recent data syntheses have clarified future relative sea-level rise exposure and sensitivity thresholds for drowning. Here, we integrate these advances to estimate when and where rising sea levels could cross thresholds for initiating wetland drowning across the conterminous United States. Our results show that there is much spatial variation in relative sea-level rise rates, which impacts the potential timing and extent of wetlands crossing thresholds. High rates of relative sea-level rise along wetland-rich parts of the Gulf of Mexico and Atlantic coasts highlight areas where wetlands are already drowning or could begin to drown within decades, including large wetland landscapes within the Mississippi River delta, Greater Everglades, Chesapeake Bay, Texas, Georgia, and the Carolinas. Collectively, our results underscore the need to prepare for transformative coastal change.

Green and Sustainable Biochar for Coastal Wetlands Management: A Review to Achieve In Situ Remediation by Artificial Intelligence

Green and Sustainable Biochar for Coastal Wetlands Management: A Review to Achieve In Situ Remediation by Artificial Intelligence

Response of dissolved inorganic carbon dynamics to simulated tidal hydrological processes in coastal wetlands

To clarify the impacts of tidal hydrological process shifts caused by sea level rise on the blue carbon cycle, a typical coastal wetland in Jiaozhou Bay was selected for this study. The soils of Suaeda salsa (SS) and Phragmites australis (PA) wetlands were collected to simulate the effects of three types of tidal hydrological processes (Neap tide group, NT; Middle tide group, MT; Spring tide group, ST) on the soil-water dissolved inorganic carbon (DIC) dynamic. The results showed that the concentration of water dissolved inorganic carbon (WDIC) increased rapidly (115% higher) at early stage (days 0–4) under the influence of the tidal hydrological processes. Significant differences were found in WDIC concentration during different tidal hydrological processes (P < 0.05), which were expressed as MT (52.7 ± 13.3 mg L−1) > ST (52.5 ± 12.9 mg L−1) > NT (48.4 ± 10.1 mg L−1). After experiencing the tidal hydrological processes, the soil DIC content showed a net accumulation (55.1 ± 1.29 mg L−1vs. 46.7 ± 1.76 mg L−1, P < 0.001), whereas the soil inorganic carbon (SIC) decreased (2.73 ± 1.64 mg L−1vs. 4.61 ± 1.71 mg L−1), which may be attributed to the dissolution of SIC caused by the uptake of CO2 to form DIC. The accumulation of soil DIC was directly related to the SIC (λ = 1.03, P < 0.01), and indirectly related to soil nutrients (SOC substrate, λ = −0.003) and microbes (microbial biomass, λ = −0.10), and was mainly dominated by abiotic processes (abiotic: 58.1 ± 1.8% to 82.7 ± 2.46% vs. biotic: 17.4 ± 2.46% to 41.9 ± 1.76%). The increase of tidal frequency generally inhibited the accumulation of soil DIC content and promoted the output of WDIC. However, the response of soil DIC in different wetland types to tidal frequency was divergent, which was mainly regulated by the trade-off between soil nutrients and SIC content. Taken together, tidal hydrological processes and their frequency changes reshaped DIC dynamics, promoted the dissolution of SIC and the potential uptake of CO2. These findings enhance the comprehension of the inorganic carbon cycle within coastal wetlands, particularly amidst the backdrop of climate change and the rising sea levels.

Spatial-temporal impacts of invasive Spartina anglica on the rates and pathways of organic carbon mineralization and resulting C-Fe-S cycles in the intertidal wetland of the Han River Estuary, Yellow Sea

To elucidate the spatial-temporal impact of invasive saltmarsh plant Spartina anglica on the biogeochemical processes in coastal wetlands, we investigated the rates and partitioning of organic carbon (Corg) mineralization in three representative benthic habitats: (1) vegetated sediments inhabited by invasive S. anglica (SA); vegetated sediments by indigenous Suaeda japonica; and (3) unvegetated mud flats. Microbial metabolic rates were greatly stimulated at the SA site during the active growing seasons of Spartina, indicating that a substantial amount of organic substrates was supplied from the high below-ground biomass of Spartina. At the SA site, sulfate reduction dominated the Corg mineralization pathways during the plant growing season, whereas iron reduction dominated during the non-growing season. Overall, due to its greater biomass and longer growing season than native Suaeda, the expansion of invasive Spartina is likely to greatly alter the Corg-Fe-S cycles and carbon storage capacity in the coastal wetlands.

Agricultural Drought Model Based on Machine Learning Cubist Algorithm and its Evaluation

Soil moisture is the most direct evaluation index for agricultural drought. It is not only directly affected by meteorological conditions such as precipitation and temperature but is also indirectly influenced by environmental factors such as climate zone, surface vegetation type, soil type, elevation, and irrigation conditions. These influencing factors have a complex, nonlinear relationship with soil moisture. It is difficult to accurately describe this non-linear relationship using a single indicator constructed from meteorological data, remote sensing data, and other data. It is also difficult to fully consider environmental factors using a single drought index on a large scale. Machine learning (ML) models provide new technology for nonlinear problems such as soil moisture retrieval. Based on the multi-source drought indexes calculated by meteorological, remote sensing, and land surface model data, and environmental factors, and using the Cubist algorithm based on a classification decision tree (CART), a comprehensive agricultural drought monitoring model at 10 cm, 20 cm, and 50 cm depth in Gansu Province is established. The influence of environmental factors and meteorological factors on the accuracy of the comprehensive model is discussed, and the accuracy of the comprehensive model is evaluated. The results show that the comprehensive model has a significant improvement in accuracy compared to the single variable model, which is a decrease of about 26% and 28% in RMSE and MAPE, respectively, compared to the best MCI model. Environmental factors such as season, DEM, and climate zone, especially the DEM, play a crucial role in improving the accuracy of the integrated model. These three environmental factors can comprehensively reduce the average RMSE of the comprehensive model by about 25%. Compared to environmental factors, meteorological factors have a slightly weaker effect on improving the accuracy of comprehensive models, which is a decrease of about 6.5% in RMSE. The fitting accuracy of the comprehensive model in humid and semi-humid areas, as well as semi-arid and semi-humid areas, is significantly higher than that in arid and semi-arid areas. These research results have important guiding significance for improving the accuracy of agricultural drought monitoring in Gansu Province.

Evaluating the Effect of Common Carp Control on Restoration of a Coastal Wetland in the Laurentian Great Lakes

Great Lakes coastal wetlands are under considerable stress from numerous anthropogenic threats, including the introduction of invasive species. Common Carp, an invasive species in North America, has been well documented as an influential wetland stressor. This study documents the impact of Common Carp reintroduction on a restored wetland fish community and abiotic and vegetation variables. Oshawa Second Marsh was restored using an exclusion berm with a fish grate and manual water-level drawdown to re-establish vegetation. Five years into restoration monitoring, Common Carp regained access to the wetland after the fish grate was vandalized. Fish community health was monitored over time using multimetric and multivariate approaches based on abiotic and vegetation variables. Improvements in fish community health were observed during restoration monitoring, but after Common Carp reintroduction, fish community health decreased and the community homogenized. Seven of the ten abiotic and vegetation variables monitored changed significantly after Common Carp reintroduction. This study highlights the impact that Common Carp has on the functional integrity of coastal wetlands and the significance of its management for restoration.

Assessment of Changes in Hydrometeorological Indicators and Intra-Annual River Runoff in the Ile River Basin

Water management strategies in the Ile River basin (Republic of Kazakhstan) have traditionally relied on historical data without fully considering the potential impacts of climate change. This gap can lead to underestimating the changes in temperature, precipitation patterns, and runoff, hindering effective water resource management. This study aimed to analyze how a changing climate is affecting the Ile River basin’s water regime. Specifically, it investigated trends in temperature, precipitation, and runoff within the basin, emphasizing the importance of incorporating these intra-annual variations when planning water management strategies and hydraulic structures. A detailed analysis of the long-term data was conducted, focusing on changes in meteorological indicators. This included average air temperatures and annual precipitation for elevations above and below 1500 m during cold and warm periods. The analysis aimed to identify and quantify trends of increase or decrease. Meteorological stations were strategically chosen to represent both arid and humid areas within the basin, accounting for the region’s significant altitude variations. The investigation revealed several key findings. Rising average annual air temperatures are leading to a larger area experiencing snowmelt and a longer warm period within the runoff formation zone. This directly impacts the water balance of the basin. Additionally, an increase in total annual precipitation, particularly during the cold season within the runoff formation zone, suggests a potential for future water resource growth, assuming that these trends persist. This study highlights the importance of considering intra-annual variations in water regimes when developing water management strategies. The observed changes in temperature and precipitation patterns within the Ile River basin necessitate adjustments to existing plans to ensure sustainable water resource management in a changing climate.

Reseeding inhibits grassland vegetation degradation – Global evidence

Global grassland faces different degradation degrees, and reseeding is commonly used to restore degraded grasslands. However, the factors affecting the results of reseeding restorations worldwide remain unclear. Here, we screened 141 independently published articles and performed a meta-analysis of the extracted 1386 data pairs. We selected five quantitative indices and four α diversity indices to analyze the effects of reseeding on the degraded grassland. Our results showed that reseeding significantly increased the quantitative indices and diversity index of degraded grasslands worldwide. Mixed reseeding has the best effect on improving the diversity of degraded grassland. A high mixed reseeding number was more conducive to restoring degraded grassland diversity. The more severe the grassland degradation, the better the restoration effect of reseeding. Short- and medium-term restorations significantly increased the diversity of degraded grassland. However, the restoration time increased the response proportion of aboveground biomass and cover. After reseeding, the proportion of aboveground biomass (AGB) response in humid areas was greater than in arid regions. This study explored the overall effect of reseeding restoration and the factors affecting reseeding restoration, providing a basis for the global restoration of degraded grassland and promoting the healthy development and sustainable use of grassland.

Comparison of coastal wetland inventories for representative sites in the United States and implications for change detection

Comparison of coastal wetland inventories for representative sites in the United States and implications for change detection

First evidence of plastics in coypu (Myocastor coypus)'s platforms.

Platforms are structures built by coypus for various purposes, such as reproduction, resting, and thermoregulation. In a coastal wetland of central Italy, during a study aimed at investigating the characteristics of coypu's platforms, it was recorded, for the first time worldwide, the presence of plastic in these structures. Through a transect survey, we censused 83 platforms, among which three (3.61%) were found with presence of macro- and megaplastics (polystyrene, polypropylene, and low-density polyethylene in film form; polyester, polyamide, and expanded polystyrene in fragments). Through the FTIR spectra, it was possible to highlight the degradation of the polymeric materials. To stimulate possible in-depth investigations at the level of the food chain (e.g., coypu predators, including canids) in wet habitats, we discussed possible causes and implications of plastic presence in coypus' nest structures.

Divergence in spatial patterns of leaf stoichiometry between native and non-native plants across coastal wetlands

The spatial pattern of leaf stoichiometry is critical in predicting plant palatability and ecosystem productivity and nutrient cycling rates and thus is a major focus of community ecological research. Coastal wetlands as vital blue carbon ecosystems, with high possibility to be vulnerable to plant invasion, studies focused on stoichiometry and its pattern are important to unveil the elements cycling process. However, previous studies have mainly focused on stoichiometry in terrestrial ecosystems, there are few studies conducted on coastal wetland ecosystems, especially the studies that compare leaf stoichiometry between native and non-native plants in coastal wetlands. In this study, we compared the latitudinal patterns of leaf nutrient contents and their stoichiometric ratios between native and non-native plant species across coastal wetland ecosystems and investigated whether leaf stoichiometric patterns were driven by climatic factors. We used a compiled global data set of 954 records to conduct a systematic meta-analysis. The results showed that there were significant differences in latitudinal patterns of leaf carbon (C) and nitrogen (N) contents and C:N ratio between native and non-native species, as well as significant differences in leaf C, N, and phosphorus (P) contents. For native species, we found significant latitudinal patterns in leaf C, N, and P contents and C:N and C:P ratios, whereas for non-native species, we found significant latitudinal patterns in leaf N content and C:P and N:P ratios. Mean annual temperature of the data collection site was a significant predictor of leaf stoichiometry of native plants but only of leaf N content and C:P ratio of non-native plants. Thus, we demonstrated spatial heterogeneity in leaf stoichiometries between native and non-native plants in coastal wetlands, indicating that such differences should be emphasized in future biogeochemical models and plant-herbivore interaction studies owing to the important role of wetland plants in global C, N, and P cycles. Our findings increase understanding of plant-related nutrient and elements cycling in coastal wetlands, as well as improve predictions of plant growth rates and vegetation productivity across large scales under plant invasion scenarios.

The impact mechanism of human activities on the evolution of coastal wetlands in the Liaohe River Delta

IntroductionThis study aims to investigate the impact of human activities on the evolution of coastal wetlands in the Liaohe River Delta. Understanding these impacts is crucial for the management, protection, and sustainable development of the ecological environment in the region.MethodsQuantitative analysis of the evolution of coastal wetlands along the Liaohe River from 1995 to 2020 using Landsat series remote sensing images. This study examines the changes in different landscapes and explores the impact of human activities on wetlands through methods such as land transfer matrix, landscape pattern index, and human activity hotspots.ResultsThe results show that the area of coastal wetlands in the Liaohe River Delta exhibited a fluctuating downward trend from 1995 to 2020. The eastern and western parts of the delta experienced greater disturbance to wetland landscapes due to human activities, while the northern and southern parts were mostly waters and reed lands with a smaller degree of human disturbance. Human activities have led to significant changes in farmland, ponds, rice paddies, construction land, and reed fields, thereby promoting the evolution of coastal wetlands.DiscussionThis article discusses the characteristics of landscape pattern evolution in the study area, as well as the impact of human interference, economy, policies, and other factors on it, and compares it with the evolution patterns of other coastal wetlands in China. The changes in the landscape pattern of the study area are mainly reflected in the reduction and fragmentation of natural wetland areas, which are closely related to human activities, especially the development of construction and agriculture. The main economic manifestation is that the increase in land demand due to economic and urban development has led to the transformation of natural wetlands into construction land and other artificial landscapes. The implementation of regulations such as the Wetland Protection Law has contributed to the rational use and ecological restoration of wetlands, and also reflects the influence of policy factors. Compared with other studies, coastal wetlands in China generally face issues of degradation and loss, mainly caused by human activities, but also affected by natural factors such as rising sea levels, changes in coastlines, and climate change.

Food Sovereignty in Nepal : A Current Appraisal

Food sovereignty issue is integrated with agro ecology, climate and environmental justice, right of food workers, agrarian reform and justice to women and peasants. Despite of the promises of food security by the use of new practices and technologies global hunger has significantly increased. Industrial food production and indiscriminant use of chemical fertilizers pesticides have caused air, water and soil pollution and consequently environment and human health has been seriously impaired. Nepal being a developing economy could hardly endow all her possible resources just to address food security issue, hence the food sovereignty issue remained veiled till 2075B.S. Present study aims to enquire the working status of food sovereignty principal on real grounds in the country. The study is based on secondary data and is quantitative in nature. As pre design it is descriptive and prescriptive both. The study examines efficacy of food sovereignty principal on six pillar of it which are: focus on food for people; Value food providers; localize food system; puts control locally; builds knowledge and skills and work with nature. Examining through facts and figures, it is found that there is food crisis in the country with its quantity and nutritive value. The extended net works of cooperative throughout the country may play significant role in activating food sovereignty principals. Existences of middle man, poorer financial assistance, poorer insurance coverage, limitation of minimum price support policy to fewer crops are some of the major problems. In addition land fragmentation, diminishing wet and dry land area are additional bottlenecks. Indiscriminant use of chemical fertilizers and pesticides pose a crucial problem to practice organic farming. Activities as river bed farming, tharu alu cultivation, Jhol mal preparation, kitchen gardening, community seed bank and use of local biochar are working well with positive outcomes to support food sovereignty efforts.

Impact assessment of agricultural droughts on water use efficiency in different climatic regions of Punjab Province Pakistan using MODIS time series imagery

AbstractDrought is the most destructive phenomenon that distresses the terrestrial carbon cycle balance and crop production. The variation in evapotranspiration (ET) and gross primary productivity (GPP) is a significant cause of agricultural drought effects on water use efficiency. This study aims to evaluate the impact of agricultural drought on WUE and it's anomalies in different climate regions. The standard vegetation index was used to measure the extent of agricultural drought. WUE was calculated using the ratio of ET, GPP, and climate classification using the De Martonne method. This study was conducted over the last 22 years, from 2001 to 2022. Meanwhile, 2001, 2002, 2014, and 2018 were considered high drought years based on a 22‐year analysis. According to remote sensing analysis of ET and GPP, the WUE increased throughout drought in all climate regions and more strongly in the arid zone than in humid regions. Humid areas were more vital due to drought than arid ones. WUE anomalies badge with increased drought severity across all climates except the very humid zone. Humid climates saw faster recovery times than arid ones, and areas experienced severe droughts. The findings of this research are essential for understanding the carbon and water cycles for agriculture management. The analysis of drought severity and WUE across arid climate regions helped analyse the varying impact of drought on WUE due to climate change. The significance of this study includes informing agricultural, water resource, and drought management planning in the Punjab Province, an agricultural region vulnerable to climate change. This study holds important learnings for agricultural regions worldwide. It has practical and scientific importance regarding agricultural systems' specific stresses and responses to droughts.

Optimizing faade shading design for public buildings in China's hot and humid regions: A comprehensive analysis

This paper presents a comprehensive analysis of faade shading design methods tailored for public buildings in Chinas hot and humid regions. Through a multidisciplinary approach integrating climatic analysis, quantitative modeling, and architectural principles, the study investigates the critical role of shading in enhancing energy efficiency and occupant comfort. Highlighting the climatic characteristics and solar radiation impact specific to hot and humid areas, the analysis underscores the necessity of tailored shading solutions. A review of traditional and modern shading strategies, alongside case studies, elucidates successes, limitations, and emerging trends. The paper also delves into mathematical modeling techniques for optimizing shading efficiency and explores the integration of shading with architectural design and renewable energy systems. The findings advocate for a holistic approach to faade shading, emphasizing its significance in achieving sustainable building practices in hot and humid climates.

Morphology, Biochemistry and Distribution of Villorita cyprinoides and Meretrix casta (Bivalve) Shells in Vembanad Estuary, Kerala, India

Estuaries are among the most commercially significant ecosystems on the earth, and they provide different habitats for numerous bivalve species. The Clams are one of the most widely distributed and used aquatic bivalves, providing much more protein-rich food than mussels and oysters. The Vembanad Estuary is one of the richest clam fisheries coastal wetland in Kerala. The present study focusing on comparatives ofmorphology and biochemistry of Villorita cyprinoides and Meretrix casta shells in Vembanad Estuary. It also attempts to understand the variations in clam distribution caused by salinity fluctuations and sediment texture. According to the morphological and morphometric analysis, medium size shells were found in greater abundance in both species. Atotal of 306 shells of V. cyprinoides and 169 shells of M. casta were obtained from the ten sample locations of Vembanad Estuary. The density of V. cyprinoides shells (192) was higher in the southern part while the northern portion of Vembanad Estuary represented by M. casta shells (108) with comparatively lower density. V. cyprinoides has a negative linear correlation with salinity, as indicated by R2 of 0.96. M. casta, on the other hand, exhibits a positive correlation with salinity, with 0.94 linear coefficient. V. cyprinoides was more prevalent in clayey and silty sediments, while M. casta was more common in sandy sediments. The X-ray Fluorescence (XRF) analysis showed that the Calcium Oxide percentage of V. cyprinoides and M. casta shells were 39.47% and 38.72%, respectively, while all other metal oxides were present only in trace amount. Keywords: Bivalves, Villorita cyprinoides, Meretrix casta, Major Oxides, Vembanad Estuary