Search Results (413)

Accurate mapping of thermokarst lakes in the Qinghai–Tibet Engineering Corridor is important for understanding permafrost degradation and assessing environmental risks to major infrastructure. However, thermokarst lake extraction from medium-resolution satellite imagery remains challenging because these lakes are often small, fragmented, seasonally variable, and spectrally confused with wetlands, shadows, and other surface water bodies. In this study, Sentinel-2 imagery from the 2020 thaw season was used to map thermokarst lakes in the Qinghai–Tibet Engineering Corridor. A 16-feature dataset was constructed by integrating spectral bands, water indices, texture features, and topographic variables, and a convolutional neural network (CNN) was compared with five conventional machine learning classifiers. In the pixel-based validation, the CNN slightly outperformed the other evaluated models, achieving the overall accuracy of 98.04% and an F1-score of 97.18%. Independent polygon-based validation using the Jilin-1 visual interpretation reference showed that the final CNN-derived inventory achieved an IoU of 0.79, with omission and commission ratios of 0.15 and 0.09, respectively. The CNN more effectively suppressed salt-and-pepper noise, reduced fragmented and serrated lake boundaries, and improved the spatial continuity of mapped water bodies compared with traditional machine learning classifiers. SHAP-based attribution suggested that CNN predictions were more strongly associated with water indices and texture features, whereas Random Forest predictions were mainly associated with near-infrared and shortwave-infrared bands. Thermokarst lakes showed higher lake area proportions and densities in areas with relatively high ground ice content, gentle slopes, thicker active layers, warmer permafrost, and unstable permafrost conditions. These results demonstrate the potential of Sentinel-2 imagery and convolutional models for regional thermokarst lake mapping and permafrost degradation monitoring. Full article

Biogenic or microbial methane (CH₄) emissions, believed to be the main driver of the recent surge in global atmospheric CH₄ emissions, have altered monitoring, measurement, and mitigation of fossil-fuel emissions. As of 1981, over 20% of the world’s natural gas reserves were biogenic in origin. Additional biogenic CH₄ reserves from coal have been discovered since 1981 mixed (40–80%) with thermogenic CH₄. Biogenic CH₄ accumulates up to 100% in coal reservoirs in the Powder River Basin (PRB), USA. Biogenic CH₄ is generated by microbial breakdown of fossil organic matter as an early-stage (primary) type during burial over geologic time and is rarely preserved. Also, biogenic CH₄ is generated as a late-stage (secondary) type from recent geologic to present times and is commonly preserved. Late-stage biogenic CH₄ is sustained by nutrients and microbes in meteoric/surface waters discharged into coal aquifers. Groundwater is pumped from wells in coal aquifers to desorb and produce CH₄ and dewater coal mines. The co-produced water with dissolved CH₄ is discharged into diverse surface aquatic systems. The emission factors (EFs) of co-produced water are 2.0522 × 10⁻⁹ Gg CH₄/gal of water in the PRB and 2.0694 × 10⁻³ Gg CH₄/well in the Black Warrior Basin, U.S. Accurate data on biogenic CH₄ emissions from coal sources is a major gap in the accounting of current global groundwater-driven CH₄ whose average flux is estimated to be 3.9 ± 6.2 mmol/m²/day or accounting for up to 70% of CH₄ emissions from surface aquatic systems. Biogenic CH₄ emissions from coal mining and coalbed gas extractions and related infrastructures are overlooked because the focus has been on coalmine methane (CMM) emissions. CMM data from ground-based measurements is highly variable and used by the Intergovernmental Panel on Climate Change three-tier system to estimate EFs for national inventories. However, 90% of CMM emissions are attributable to a small group of the most coal-consuming-and-producing countries but fails to capture other coal sources worldwide. This created gaps and “blind spots” in “unstructured” low-concentration, diffused biogenic CH₄ emission data. These key “blind spots” include sources from flooded, abandoned coal mines; coalbed methane (CBM) co-produced water with dissolved CH₄ and infrastructures/facilities; and groundwater drawdown from water withdrawals during coal mining and CBM extraction. Also, a critical “blind spot” is the mixing of biogenic CH₄ emissions from subsurface coals with biogenic CH₄ generated at the surface from wetlands, agriculture, and landfills/wastes, which grew 85% from 2008 to 2020. Limited understanding of the mixing of biogenic CH₄ from diverse sources and their contributions to global methane requires accurate attribution of overlapping isotopic signatures (δ¹³C_CH4 and δD). This paper addresses knowledge gaps in coalbed biogenic CH₄ emissions by a systematic review of the literature and specific study cases, which provided insights on key “blind spots” in their mitigation. Full article

Facing the intensifying challenges of global climate change, research on urban ecosystem sustainability and resilience has become increasingly urgent. This study constructs a hybrid assessment framework integrating emergy analysis, GIS, carbon accounting, and neural networks to systematically evaluate the sustainability evolution of Zhenjiang City from 2000 to 2020 and project its resilience trajectory to 2050. The results show that Zhenjiang experienced a resilience tipping point around 2015. From 2000 to 2015, the built-up area expanded by 17.5 times, droving PM_2.5 concentration to exceed 200 μg/m³ and the emergy sustainability index to decline by 59%. From 2015 to 2020, under strong policy interventions, PM_2.5 dropped sharply by 85.6%, forest area expanded by 3.5 times, and wetland emerged from none, with an accumulation–release asymmetry index greater than 2, validating the characteristics of slow accumulation and rapid recovery. Rainwater emergy accounts for more than 94% of total emergy, making it the dominant factor in the sustainability of small and medium-sized cities. Built-up areas have achieved relative carbon–emergy decoupling, while farmland faces a high carbon emission dilemma. SHAP analysis shows that the contribution of spatial ecological indicators is 3.5 times that of population density, and policy benefits exhibit a time lag of approximately 6 years. Neural network projections indicate that the comprehensive sustainability score can improve by approximately 58% by 2050, though this improvement depends on the continuous optimization of ecological space. This study provides a quantifiable assessment tool and decision-making basis for resilience management in small and medium-sized cities. Full article

Mankyua chejuense (Ophioglossaceae) is an endangered fern restricted to basaltic ephemeral wetlands on Jejudo-Island. However, its capacity to establish in transplantation habitats remains poorly understood. Its occurrence is shaped by rainfall-driven short-term inundation, rapid drying, basaltic microtopography, and seasonal light availability. We assessed its reintroduction potential through a two-year transplantation experiment using ramets collected from a natural population. Ramets were planted in two wetland-type recipient habitats: a small, microtopographically isolated wetland (WS) and a larger wetland with a steep inundation depth gradient (WL). During the 24-month monitoring period, transplanted ramets survived in both transplantation habitats, with establishment ratios of approximately 80% in WS and 55% in WL. Ramets maintained aboveground growth and reproductive structure formation, including stipe production, ramet height, vegetative pinna production, fertile segment formation, and reproductive ratio. Along the water-depth gradient in WL, deeper or fully inundated conditions tended to increase vegetative growth, particularly stipe production, whereas reproductive ratio was relatively lower under these conditions. These contrasting responses suggest a possible shift in growth–reproductive allocation along the inundation gradient. Overall, these findings indicate that M. chejuense can establish in environmentally suitable transplantation habitats when ramets are artificially introduced. Therefore, the absence of natural individuals in nearby unoccupied wetlands should not be interpreted as direct evidence of habitat unsuitability, but may instead reflect limitations in natural colonization processes, including dispersal arrival, germination, early establishment bottlenecks, and fine-scale microtopographic or hydrological filtering. Full article

Despite their size, small wetlands play a vital role in maintaining ecosystem stability. To clarify the pollution levels as well as potential ecological and health risks of potentially toxic elements (PTEs) in small wetlands, 85 water samples were collected from small wetlands in the Baghrash Lake Basin (BLB) of China, and six PTEs (As, Cd, Cu, Hg, Pb, and Zn) were determined for their contents. The Nemerow integrated pollution index (NPI) was adopted to evaluate PTE pollution levels. The ecological risk index (RI) and USEPA health risk assessment model were further applied to quantify potential ecological and health risks of PTEs, respectively. The results revealed that PTEs in small wetlands showed a slight pollution level, with an average NPI value of 0.73. Meanwhile, the integrated ecological risk index of PTEs showed a low ecological risk level, with an average RI value of 23.041. Health risk assessment results demonstrated that the non-carcinogenic risk of PTEs in small wetlands remained at a negligible level, while the carcinogenic risk stayed within acceptable limits for both local population groups: children and adults. Among all detected PTEs, Hg was identified as the primary pollutant and major ecological risk factor, while As posed the highest relative potential health risk while overall risks remained acceptable. The findings of this study can provide a scientific basis for the environmental protection of small wetlands in the BLB. Full article

Currently, in Catalonia, Spanish toothcarp (Apricaphanius iberus) has a discontinuous distribution, with its main populations located in the Ebro Delta and the Empordà wetlands. Along the Catalan coast, there are some small, isolated populations, most of which have been recently introduced. In the Empordà area, this species still maintains three isolated populations within two natural parks, where it currently occupies the northernmost site of its global distribution. Between 2017 and 2025, several fish sampling campaigns were carried out in the Empordà wetlands (Northeast Catalonia), gradually covering the entire area of potential distribution of this species in the area. In total, 228 points have been sampled, at least in one occasion, in all types of water bodies (rivers, canals, lagoons, marshes). In 106 points, more than two sampling events have been performed. Furthermore, in 2025, a specific diagnosis was carried out to better understand the current situation of the species in these protected spaces after a prolonged and severe drought. Sampling was carried out everywhere with fykenets, adding the use of nets and electrofishing in some stations located in large bodies of water. The known historical evolution of Spanish toothcarp distribution in the Empordà has been presented since the first data was made available at the beginning of the 1980s of the 20th century until now. Today, this fish only occupies approximately 10% of its potential distribution in the area. Over the last five decades, its distribution has expanded and contracted several times, but in 2025, it was once again in the worst possible situation of the analysis period. Therefore, the implementation of protected areas, or the execution of several large ecological restoration projects, have only succeeded in maintaining existing populations, but not in the expansion of its potential distribution to unoccupied areas. The main factors that explain this general situation are mainly (1) the proliferation of exotic species, (2) the loss of ecological status, and (3) hydrological alterations and increasingly severe droughts. Thus, the recovery and long-term conservation of Spanish toothcarp in the Empordà area inevitably requires the implementation of more extensive and decisive measures to reverse the incidence of these factors. Full article

The African jacana (Actophilornis africanus, family Jacanidae) is a sex-role-reversed waterbird inhabiting tropical and subtropical open wetlands across Africa. Identifying environmental factors that influence nest site distribution and suitable nesting habitats is crucial for protecting species and habitat management; however, studies addressing these factors remain limited for this species. This study aimed to map suitable nesting habitats and identify the main environmental variables influencing the nest site distribution of the African jacana in Lake Hawassa, Ethiopia. We mapped nesting habitat suitability using a Maximum Entropy (MaxEnt) model and ArcGIS Pro 3.2.2 based on 78 field-collected nest data points and ten environmental variables. The model predicted a total suitable nesting habitat area of 1.25 km² with high accuracy (AUC = 0.90, CBI = 0.8, and omission rate = 0.22), representing about 1.2% of Lake Hawassa’s total area. In general, suitable nesting habitats were relatively small, fragmented, and mainly clustered along the southeastern shore of Lake Hawassa. The mean precipitation and temperature during the breeding season, slope, elevation, and distance to shoreline were the main predictors of the African jacana’s nesting habitat suitability. The results of the present study provide valuable insights into local wetland management and the conservation of African jacanas and other breeding waterbirds in Lake Hawassa. Moreover, this study establishes baseline information for assessing how future climate and habitat changes may influence breeding habitat suitability in similar Ethiopian wetlands. The present study was limited to nesting habitat suitability based on limited environmental factors and did not include nest success, pollution parameters or predation; future studies incorporating these factors may improve ecological interpretation. Full article

Background: This study aims to measure Greenhouse Gas (GHG) emission fluxes at the soil–air and water–air interfaces in urban wetlands on the Qinghai–Tibet Plateau and identify the primary controlling factors. The objective is to elucidate the key drivers of carbon and nitrogen processes at different interface levels in wetlands within high-altitude urban settings, thereby providing a scientific basis for accurately estimating their contribution to greenhouse gas emissions. Results: In the wetlands of Xining City, with the exception of soil pH, bulk density, and moisture content (which showed no significant change over time), all other soil physicochemical properties differed significantly among the three wetlands and among the sampling periods (p < 0.05). Soil moisture content was less affected by variations across different wetlands and over time, and differences in soil physicochemical properties among different wetlands were small (p > 0.05). Significant differences were observed in the spatiotemporal variations in the physicochemical properties of water bodies in Xining’s wetlands (p < 0.05), although water pH and total organic carbon (TOC) were less affected by the interaction between different wetlands and time periods. There were no significant differences in the bulk density and moisture content of wetland sediments in Xining over time (p > 0.05), while all other physicochemical indicators of sediments showed significant differences (p < 0.05). The physicochemical properties of sediments were influenced by both different wetland types and different time periods. GHG fluxes at the water–air interface in Xining wetlands were greater than those at the soil–air interface; overall, GHG emissions from both interfaces acted as “sources.” Seasonal variations in wetland GHG emissions were pronounced, with emission peaks occurring from June to August. The study found that the primary soil factor influencing GHG emissions at the soil–air interface was total phosphorus (TP), while the primary sediment factors affecting emissions at the water–air interface were TP and nitrate nitrogen (NO₃⁻-N), and the primary water factor was TOC. The interannual cumulative emissions from both interfaces in the wetland totaled 705.88 g·m⁻². GHG emissions from the soil–air and water–air interfaces contributed 47.88% and 52.12%, respectively, to the global warming potential (GWP) of the wetland, while methane (CH₄), carbon dioxide (CO₂), and nitrous oxide (N₂O) contributed 32.55%, 62.33%, and 5.12%, respectively, to the GWP. Conclusions: Investigating the GHG emission patterns in Xining’s wetlands and identifying the primary factors influencing these emissions provides a scientific basis for the protection and restoration of these wetlands. This is of great significance for safeguarding the ecological security of Xining’s wetlands as well as the overall ecological security of high-altitude wetlands. Full article

Accurate prediction and assessment of carbon storage are crucial in the context of global climate change. However, existing research has largely focused on large-scale regions, while studies on small-scale ecologically fragile alpine regions remain insufficient. This study focuses on Zoige County, integrating the PLUS model, InVEST model, and Random Forest model to form a composite analysis workflow. Through this workflow, we simulated the distribution of land use types in 2030 and quantified carbon storage from 1990 to 2030, subsequently analyzing their spatial distribution and driving factors. The key findings include: (1) Under the natural development scenario (NDS) and the ecological protection scenario (EPS) for 2030, the primary land use transition involved the conversion of grassland to forest and wetland. Conversely, wetland was converted into cropland under the economic development scenario (EDS). (2) Under the NDS, EDS, and EPS, carbon storage would be 8.396 × 10⁷ t, 8.252 × 10⁷ t, and 8.432 × 10⁷ t, respectively. The EPS yielded the largest increase in carbon storage. (3) In all three scenarios, carbon storage showed a clustered distribution. Compared with 2020, the carbon storage hot spot areas under both NDS and EPS showed an expansion trend, whereas the cold spot areas also expanded in three scenarios. (4) The key drivers of carbon storage include slope, elevation, soil type, and mean annual temperature. This study concludes that the EPS represents the most favorable development pathway for carbon storage accumulation. This finding can provide a basis for future carbon storage dynamics and land use planning for Zoige County. Full article

The present study examined fish biodiversity, livelihood dependence, cultural importance, and genetic connectivity in two ecologically linked habitats of the Sylhet region, Bangladesh: Hakaluki Haor and the Surma River. Surveys documented 60 fish species with distinct assemblage patterns between sites. Hakaluki Haor was dominated by floodplain spawners and small indigenous species that contribute to year-round subsistence harvests, whereas the Surma River supported a greater proportion of migratory and pelagic species, most notably Tenualosa ilisha. These ecological contrasts reflected differences in hydrology, habitat diversity, and fishing intensity. Household surveys confirmed the central role of fisheries in sustaining income and food security, while cultural practices surrounding hilsa consumption reinforced local stewardship norms. Mitochondrial cytochrome b sequence analysis of T. ilisha revealed low genetic differentiation between sites, indicating a single, well-connected stock maintained by seasonal flooding and the absence of major migration barriers. This convergence of ecological and genetic evidence supports treating the two sites as an integrated management unit. Effective conservation will require protecting hydrological connectivity, safeguarding dry season refugia, coordinating seasonal fishing restrictions across habitats, and incorporating cultural values into policy frameworks. The findings strengthen the scientific basis for national and regional conservation strategies and demonstrate the value of combining biological, socio-economic, and cultural dimensions in managing connected wetland–river systems. This approach can serve as a transferable model for other tropical floodplain–river complexes facing similar ecological and livelihood challenges. Full article

Ecological networks provide an important spatial framework for maintaining regional ecological security in fragmented landscapes. However, structural comparison of ecological network evolution at the provincial scale remains relatively limited, especially in cold-region contexts. Taking Heilongjiang Province in Northeast China as the study area, this study applies a structure-oriented workflow integrating ecological sensitivity assessment, the Minimum Cumulative Resistance (MCR) model, and edge-betweenness-based backbone corridor extraction to examine ecological network change in 2000, 2010, and 2020. The results show that 16, 18, and 17 ecological source areas were identified in 2000, 2010, and 2020, respectively, with a relatively stable spatial distribution concentrated in forest- and wetland-dominated regions. The total length of potential ecological corridors decreased from 12,634 km in 2000 to 11,985 km in 2020. Quantitative topological indicators further indicate that the 2010 ecological network was the most compact and densely connected of the three periods, whereas the 2020 network remained connected but exhibited lower structural compactness. Backbone ecological corridors retained only a limited proportion of the full corridor network while preserving overall connectivity, indicating that a relatively small subset of structurally important corridors supported the main network framework. Spatially, structural weakening was more evident in the Harbin–Daqing region, whereas the northwestern and southeastern parts of the province maintained relatively stable ecological foundations. These patterns were broadly consistent with land-use dynamics, particularly grassland decline and built-up land expansion. Overall, this study provides an applied structure-oriented workflow for examining ecological network evolution at the provincial scale and offers a spatial basis for ecological conservation and territorial planning in cold-region provinces. Full article

Microplastic (MP) contamination has become a widespread environmental concern in coastal and freshwater wetlands, ecosystems that play a crucial role in hydrological regulation, nutrient cycling, and biodiversity conservation. Despite their ecological importance, research on MPs in wetlands remains fragmented and comparatively underexplored. This study presents a comprehensive bibliometric and visualization analysis of global research on MPs in coastal wetlands. A total of 17,523 publications were retrieved from the Web of Science Core Collection (2002–2025) using predefined search strings and screening criteria. Analytical tools, including VOSviewer version 1.6.20, were employed to examine co-authorship networks, country contributions, and keyword co-occurrence patterns. The results indicate a significant increase in MP-related publications after 2016, with China, the United States, and India emerging as leading contributors. However, wetland-specific studies constitute only a small fraction compared to marine-focused MP research, highlighting a substantial research gap. Key research themes identified include MP sources, transport pathways, sediment–water interactions, and ecotoxicological impacts. Additionally, there is growing attention to remediation approaches, particularly those involving TiO₂, ZnO, Fe₃O₄, and graphene derivatives, employing photocatalytic, magnetic, and adsorptive mechanisms. Overall, the findings underscore the limited focus on wetland ecosystems in MP research and emphasize the urgent need for integrated research efforts and management strategies to address MP contamination in these vulnerable ecosystems. Full article

Water scarcity and pollution from anthropogenic activities are major challenges, increasing the need for sustainable wastewater treatment solutions. Constructed wetlands mimic natural wetland ecosystems using macrophytes and substrates, representing a possible nature-based solution aligned with circular economy principles and the United Nations Sustainable Development Goals. So, this revision integrates recent literature, providing an overview of natural wetlands and examining the design and operation of constructed wetland systems. Also, incorporates a case study that focuses on a constructed wetland implemented at an eco-friendly dog shelter in Portugal—a unique example globally—demonstrating practical wastewater treatment and small-scale water reuse, and offering insights for sustainable management. Performance assessment based on previous work indicates that the system effectively reduces most water quality parameters to levels compliant with national and European irrigation standards. Removal efficiencies exceeded 97% for chemical oxygen demand, total suspended solids, and turbidity, while maintaining low energy consumption and minimal maintenance. Overall, constructed wetlands emerge as a sustainable alternative to conventional wastewater treatment systems; however, several challenges remain to be addressed. Future research should focus on improved aeration strategies, optimized substrate–macrophyte combinations, and long-term monitoring under climate variability, with floating wetlands offering promising opportunities to further enhance treatment efficiency. Full article

Wetlands are the largest natural source of atmospheric methane (CH₄), and their emissions are projected to increase during the 21st century in response to climate change. However, how extreme climate events such as extreme heat, extreme precipitation, and their compound occurrences modulate future wetland methane emissions, remains poorly constrained. Here, we quantify the impacts of extreme temperature, precipitation, and compound hot–wet events on global wetland methane emissions (eCH₄) using simulations from the dynamic global vegetation model LPJ-wsl driven by four CMIP5 climate models under a high-emission scenario (RCP8.5) for the period 2006–2099. Our results show that extreme heat events intensify and become substantially more frequent, with global occurrence increasing by more than 303% by the end of the century. Correspondingly, their contribution to global wetland methane emissions rises from ~26–28% in 2006 to ~73–83% by 2099, making extreme heat the dominant driver of future eCH₄ increases. Extreme precipitation events exhibit relatively modest changes in frequency and mixed intensity. In contrast, compound hot–wet events, despite their low baseline frequency, increase by more than 600% and are associated with disproportionately strong methane responses, driven by the combined effects of elevated temperatures and enhanced anaerobic conditions. Across all event types, tropical wetlands account for 75–90% of global methane emissions, while contributions from mid-latitudes increase modestly and high-latitude contributions remain comparatively small. These findings highlight the emerging importance of climate extremes—particularly extreme heat and compound hot–wet events—in shaping future wetland methane emissions. Explicit consideration of extreme-event dynamics is therefore essential for improving projections of methane–climate feedback under continued global warming. Full article

The Somyne lake-mire system is a unique wetland landscape complex in the Polissia region of Ukraine and forms part of the Rivne Nature Reserve. Its ecological importance is internationally recognised through its designation as the Ramsar wetland “Somyne Peatland Massif”. Effective conservation of this wetland requires an understanding of the factors controlling the functioning of the lake and its drainage basin, considered in this study as a lake-basin system (LBS). The aim of this study is to assess the geoecological condition of the Somyne LBS using the principles of landscape limnology and the basin approach. The research integrates morphological, morphometric, hydrological, landscape-metric, hydrochemical and geochemical analyses. These are complemented by bathymetric modelling, landscape mapping, and analysis of long-term meteorological observations. The results identify key natural and anthropogenic drivers shaping the functioning of the system, characterise the hydrochemical state of lake waters and the geochemical properties of bottom sediments, and describe the spatial distribution of bottom sediments and the bathymetric structure of the lake basin. A multivariate algorithm for the geoecological assessment of lake-basin systems is proposed, providing a framework for comparative analysis of small lakes in the Polissian lake region under climate change and increasing anthropogenic pressure. Full article