Search Results (4,991)

Soil nitrogen (N) and phosphorus (P) loss in watersheds is a critical source of water pollution. This study explores the spatial distribution, release potential, and environmental impacts of soil N and P in the downstream Daliao River basin by integrating field investigations and simulation experiments. Results showed that total nitrogen content in soils ranged from 256.09 to 3362.75 mg/kg, while that in sediments ranged from 114.85 to 1640.54 mg/kg. Total phosphorus content in soils varied from 250.18 to 1142.69 mg/kg, whereas in sediments it ranged from 327.23 to 586.24 mg/kg. The ammonia nitrogen release potentials of soils collected from rice paddies, corn farmlands, roadsides, and reed wetlands were 0.75, 0.86, 0.70, and 8.65 mg/L, respectively, with corresponding total phosphorus release potentials of 0.61, 1.01, 0.31, and 1.52 mg/L. For sediments, ammonia nitrogen and total phosphorus release potentials ranged from 0.96 to 1.21 mg/L and 0.44 to 0.52 mg/L, respectively. Temperature, pH, and dissolved oxygen were important factors influencing nitrogen and phosphorus release from soils and sediments. The export of nitrogen and phosphorus from soil reached 50.50 t/a and 21.63 t/a, respectively. During the soil erosion process in the Daliao River Basin, phosphorus exhibited a high release potential and served as the primary pollutant, whereas the release mechanism of ammonia nitrogen was more complex, showing seasonal variability. Soils in the downstream Daliao River basin have large specific surface areas and may pose a high pollution risk after discharge into water bodies due to prolonged adsorption of pollutants. It is recommended to propose promoting soil testing-based fertilization, constructing ecological engineering projects, developing sponge cities, and conducting environmental dredging to reduce N and P release from agricultural lands, construction areas, natural wastelands, and sediments. Full article

Urban wetlands are strategic socio-ecological systems that provide diverse cultural ecosystem services, including recreation, environmental education, and spiritual connections with nature. At the same time, they can generate ecosystem disservices, undermine human well-being, and challenge urban sustainability. This study investigates visitors’ perceptions of such disservices in three Ramsar-designated wetlands in Bogotá, Colombia (Santa María del Lago, Juan Amarillo, and Córdoba) to assess their influence on tourist experiences and their potential role in fostering urban peace. A mixed-methods approach was employed, combining structured surveys, quantitative analysis, and qualitative coding. The results reveal that pollution, insecurity, and unpleasant odors significantly reduce visitors’ willingness to return, with notable variations across gender groups and wetland sites. Visitors also emphasized the need to strengthen infrastructure, surveillance, and environmental education. These findings underscore the importance of incorporating disservice analysis into wetland governance as a strategy to advance regenerative tourism, promote environmental justice, and support peacebuilding in Latin American metropolitan contexts, with broader implications for global urban sustainability. Full article

Decontamination of wastewater, industrial effluents, stormwater, and graywater can be carried out through the use of natural or constructed wetlands. In either case, the natural functions of soil, vegetation, and organisms are widely applied for the treatment of contaminated water. In particular, in the physical design of a constructed wetland, several operational factors must be adjusted with the aim of reducing pollution levels. Although various fully customized design methodologies have been developed and reported in the literature, they often fail to meet the required decontamination objectives. In this context, the application of the NSGA-II evolutionary algorithm is adequate to optimize the physical design of a horizontal subsurface flow wetland for graywater treatment, focusing specifically on the removal of biodegradable organic matter (BOD${}_5$). Four competing objectives are considered: minimizing physical volume and total design cost, while maximizing contaminant removal efficiency and graywater flow rate. Five constraint functions are also incorporated: removal efficiency greater than 95%, physical volume below 1000 m${}^3$, flow rate above 10 m${}^3$/d, a limit on total construction cost of MXN 1,000,000, and maintaining a length-to-width ratio greater than or equal to 2 but less than or equal to 4. The proposed methodology generates a wide set of non-dominated solutions, visualized through Pareto surfaces, which highlight the trade-offs among different objectives. This approach offers the possibility of selecting optimal designs under specific conditions, which underscores the limitations of conventional single-solution models. The results show that the methodology consistently achieved removal efficiencies above 95%, with construction costs within budget and physical volumes below the established limit, offering a more versatile and cost-effective alternative. This work demonstrates that the integration of NSGA-II into wetland design is an effective and adaptable strategy, capable of providing sustainable alternatives for graywater treatment and constituting a valuable decision-making tool. Full article

Pharmaceuticals such as ibuprofen, paracetamol, and caffeine are commonly found in wastewater due to incomplete removal in conventional treatment systems. This study evaluated three vertical constructed wetland (V-CW) configurations: V1 (gravel–sand with vegetation), V2 (biochar–zeolite with vegetation), and V3 (biochar–zeolite without vegetation). All systems achieved high removal efficiencies for organic matter (Chemical Oxygen Demand (COD): 89.4–91.7%, Biochemical Oxygen Demand over 5 days (BOD₅): 93.3–93.8%, Total Suspended Solids (TSS): 94.5–96.6%) and pharmaceuticals (ibuprofen: 81.8–91.5%, paracetamol: 90.0–94.3%, caffeine: 93.1–97.2%). Statistical analysis showed that substrate type significantly influenced ibuprofen (p = 0.0035) and caffeine (p = 0.0436) removal, while vegetation had no significant effect (p > 0.266). The enhanced performance of biochar and zeolite can be attributed to their high adsorption capacity and microbial support, with adsorption and biodegradation identified as dominant removal mechanisms, as reported in previous research. These findings highlight the importance of engineered substrates in optimizing constructed wetlands for wastewater treatment to improve the removal of emerging contaminants. Future research should focus on long-term substrate performance, cost-effectiveness, and field-scale validation, particularly in regions with vulnerable groundwater systems such as the Yucatán Peninsula. Full article

Birds, as both wetland ecosystem health indicators and highly perceptible forms of wildlife, provide multi-sensory interaction opportunities shaping human health and well-being. However, most studies simplify birds into static landscape metrics, with limited attention to dynamic human–bird interactions and their mental health benefits. Grounded in landscape perception theory, this study constructs an “interaction–perception–restoration” framework and divides human–bird interactions into sensory, cognitive, and participatory levels based on cognitive resource investment. We collected 321 valid samples from Haizhu National Wetland Park. A mixed analytical strategy was adopted, using structural equation modeling to test the framework and moderated mediation models to examine differential pathways. The results showed the following: (1) Restorative environmental perception (REP) plays a partial mediating role between human–bird interactions and mental health, explaining 46.17% of the total effect. (2) All three interaction levels significantly enhance mental health, with cognitive interaction showing the strongest direct effect (β = 0.347 ***) and sensory interaction the largest indirect effect through REP (β = 0.194 ***). (3) Environmental characteristics directly improve REP (β = 0.51 ***) but do not significantly moderate the relationship between human–bird interactions and REP. This study highlights interaction quality and depth as core drivers of mental health, offering insights for optimizing ecological and recreational services in urban wetland parks. Full article

The Tibetan Plateau is a globally critical climate-sensitive and ecologically fragile region. Vegetation phenology serves as a key indicator of ecosystem responses to climate change and simultaneously influences regional carbon cycling, water regulation, and ecological security. However, systematic quantitative assessments of phenological responses under the combined effects of multiple climate factors remain limited. This study integrates multi-source remote sensing data (MODIS MCD12Q2) and ERA5-Land meteorological data from 2001 to 2023, leveraging the Google Earth Engine (GEE) cloud platform to extract key phenological metrics, including the start (SOS) and end (EOS) of the growing season, and growing season length (GSL). Sen’s slope estimation, Mann–Kendall trend tests, and partial correlation analyses were applied to quantify the independent effects and spatial heterogeneity of temperature, precipitation, solar radiation, and evapotranspiration (ET) on GSL. Results indicate that: (1) GSL on the Tibetan Plateau has significantly increased, averaging 0.24 days per year (Sen’s slope +0.183 days/yr, Z = 3.21, p < 0.001; linear regression +0.253 days/yr, decadal trend 2.53 days, p = 0.0007), primarily driven by earlier spring onset (SOS: Sen’s slope −0.183 days/yr, Z = −3.85, p < 0.001), while autumn dormancy (EOS) showed limited delay (Sen’s slope +0.051 days/yr, Z = 0.78, p = 0.435). (2) GSL changes exhibit pronounced spatial heterogeneity and ecosystem-specific responses: southeastern warm–wet regions display the strongest responses, with temperature as the dominant driver (mean partial correlation coefficient 0.62); in high–cold arid regions, warming substantially extends GSL (Z = 3.8, p < 0.001), whereas in warm–wet regions, growth may be constrained by water stress (Z = −2.3, p < 0.05). Grasslands (Z = 3.6, p < 0.001) and urban areas (Z = 3.2, p < 0.01) show the largest GSL extension, while evergreen forests and wetlands remain relatively stable, reflecting both the “climate sentinel” role of sensitive ecosystems and the carbon sequestration value of stable ecosystems. (3) Multi-factor interactions are complex and nonlinear; temperature, precipitation, radiation, and ET interact significantly, and extreme climate events may induce lagged effects, with clear thresholds and spatial dependence. (4) The use of GEE enables large-scale, multi-year, pixel-level GSL analysis, providing high-precision evidence for phenological quantification and critical parameters for carbon cycle modeling, ecosystem service assessment, and adaptive management. Overall, this study systematically reveals the lengthening and asymmetric patterns of GSL on the Tibetan Plateau, elucidates diverse land cover and climate responses, advances understanding of high-altitude ecosystem adaptability and climate resilience, and provides scientific guidance for regional ecological protection, sustainable management, and future phenology prediction. Full article

Low temperature combined with fluctuating irradiance frequently co-occurs and suppresses photosynthesis, with irreversible injury to photosystem I (PSI) recognized as a key constraint on growth and yield. To test whether exogenous hydrogen sulfide (H₂S) mitigates this “cold–fluctuating light” stress in mulberry, we established six treatment combinations (room temperature controls, sodium hydrosulfide, and hypotaurine, each with or without low temperature plus fluctuating light). We quantified PSI/PSII photochemical properties, gas exchange, reactive oxygen species (ROS), and antioxidant enzyme activities. Under cold with fluctuating light, PSI was strongly inhibited: Y_NA increased, whereas Y_I and ΔI/I_o decreased, and the P700 re-reduction half-time (t½) was prolonged (ANOVA, Tukey’s HSD, p < 0.05), indicating pronounced acceptor-side over-reduction and impaired electron transport. PSII performance also declined (lower F_v/F_m and PI_ABS, higher ΔV_J; p < 0.05). NaHS pretreatment significantly alleviated these effects relative to the stressed control: PSI/PSII metrics partly recovered, net photosynthetic rate (P_n) and water-use efficiency (WUE) increased, H₂O₂ and MDA decreased, and SOD/POD/CAT activities rose (p < 0.05). Notably, NPQ_high correlated negatively with Y_NA (Pearson r < 0, p < 0.001), consistent with the notion that enhanced energy dissipation relieves PSI acceptor-side limitation. We propose that exogenous H₂S stabilizes electron transport and supports carbon assimilation via a dual strategy—faster engagement of energy dissipation and activation of antioxidant defenses—highlighting its potential utility for managing stress in fruit crops under erratic early-season weather. Full article

A multiproxy study of a new Pleistocene locality at Ivantzevo, Moscow Region, was conducted to reconstruct paleoenvironments from the Middle Pleistocene to the Last Pleniglacial. Lacustrine deposits and peat accumulated in a wetland within a fluvioglacial depression formed during the Dnieper–Moscow glaciation. Silts and clays were deposited during MIS 7 and the Moscow (Saale) Glaciation (MIS 6), while peat accumulation began in the Mikulino (Eemian) (MIS 5e). The wetland persisted for approximately fifty millennia, until the Middle Valdai (Weichselian). Interglacial peat deposits contain well-preserved pollen and macrofossils, and the recovered fossil insect assemblage is unique for European Russia. Chronology was established using multiple OSL and ²³⁰Th/U dates, combined with pollen-based correlations to type sections north and west of the region. The reconstructed ecosystem dynamics are divided into eleven stages. The transition from the last interglacial to the second stadial of the Valdai involved seven phases: (1) expansion of boreal spruce forest, (2) spread of thermophilic broad-leaved forests with hazel, (3) development of open forest–steppe ecosystems with groves of deciduous trees, (4) re-establishment of forest cover with birch and, later, mixed pine, spruce, and birch forests, (5) emergence of cold steppe combined with shrub-dominated tundra, (6) return of boreal spruce forest, and (7) abrupt replacement of forest by cold steppe and shrub tundra. Climatic reconstructions indicate that these ecosystem dynamics closely corresponded to changes in precipitation and aridity. Full article

Arundo donax L. (common reed), a highly invasive species in Mediterranean wetlands such as the Albufera Natural Park, poses significant ecological and management challenges. Using Landsat-5 and Sentinel-2 NDVI data, this study quantified changes in its coverage between 1996 and 2024. The results reveal a significant expansion, showing a decreasing trend (91.4 ha in 1996 to 62.5 ha in 2011; −31.6%) followed by a clear rebound (83.5 ha in 2024; +33.6%), especially in the southern shrublands of the lagoon. A Mann–Kendall analysis confirmed a significant decreasing trend during 1996–2011 and an increasing trend during 2011–2024 (p < 0.05). The results indicate that previous control efforts reduced A. donax cover but that the species has recolonised after 2011, likely due to discontinuous management. These dynamics emphasise that long-term monitoring is required. Management strategies must focus on targeting the rhizome and implementing long-term monitoring programmes spanning three to five years. The utilisation of remote sensing methodologies proved effective in the monitoring of coverage, thereby facilitating the development of remediation strategies. It is imperative that actions accord primacy to critical areas such as the south and canals, complemented by native restoration and enhanced inter-administrative coordination, with the communication of benefits such as flood risk reduction. A balanced approach is required that considers ecological objectives, risks, and socio-political aspects. Full article

Landscape fragmentation is a dynamic process with multiple effects. In addition to reducing the area of priority ecosystems such as mangroves, it also generates alterations in ecological functions and environmental processes, with significant socioeconomic and ecological consequences. The objective of this research was to determine the impact of anthropic development on landscape fragmentation within the Environmental System (ES) that includes the Arroyo Moreno Ecological Reserve (REAM) and the Tembladeras-Laguna Olmeca Ecological Reserve (RETLO), located in central Veracruz Mexico. Fragstats V4.3 Beta software was used to analyze landscape metrics at the patch, class, and landscape levels, using nine indicator metrics for assessing fragmentation. The analysis of the metrics at the three levels showed a reduction in the total area for some classes such as Mangrove (MG), Water Bodies (WB), and Agricultural and Livestock (AL). Class-level metrics such as total area, percentage of landscape, and number of patches showed greater differences for some classes between 2001 and 2023. However, some values increased in 2015. However, this research is considered the first study conducted in the area to comprehensively use a set of landscape metrics at three organizational levels, offering a more accurate description of the status of priority ecosystems (RAMSAR sites) such as the wetlands of the coastal zone of Veracruz. It also demonstrated the importance of the constantly expanding anthropic development in the study area over the last 20 years and the potential pressure it exerts on biodiversity conservation sites such as wetlands. Full article

Tidal flats, as critical transitional ecosystems between land and sea, face significant threats from climate change and human activities, necessitating accurate monitoring for conservation and management. However, publicly available tidal flat datasets exhibit substantial discrepancies due to variations in data sources, spectral indices, and classification methods. This study systematically evaluates six widely used 2020 tidal flat datasets (GTF30, GWL_FCS30, MTWM-TP, DCTF, CTF, and TFMC) across China’s coastal zone, assessing their spatial consistency, area estimation differences, and edge classification accuracy. Using a novel edge validation point set (3150 samples) derived from tide gauge stations and low-tide imagery, we demonstrate that MTWM-TP (OA = 0.85) and TFMC (OA = 0.84) achieve the highest accuracy, while DCTF and GTF30 show systematic underestimation and overestimation, respectively. Spatial agreement is strongest in Jiangsu (49.8% unanimous pixels) but weak in turbid estuaries (e.g., Zhejiang). Key methodological divergences include sensor resolution (Sentinel-2 outperforms Landsat in low-tide coverage), spectral index selection (mNDWI reduces false positives in turbid waters), and boundary constraints (high-tide masks suppress inland misclassification). We propose establishing an automated multi-source framework integrating optical (Sentinel-2, Landsat) and radar (Sentinel-1) observation data to enhance low-tide coverage, constructing region-adaptive spectral indices and improving boundary accuracy through the combination of machine learning and thresholding algorithms. This study provides a critical benchmark for dataset selection and methodological advancements in coastal remote sensing. Full article

Accurate assessment of avian community structure and bird-strike risk within airport ecosystems is vital for balancing aviation safety with biodiversity conservation. From October 2019 to July 2020, we conducted systematic bird surveys at Lincang Boshang Airport (Yunnan, China) and its surrounding area. By integrating taxonomic, functional, and phylogenetic diversity analyses, we examined spatial–temporal patterns of bird diversity and characterized bird-strike risk. In total, 4859 individuals of 148 species were recorded, representing 51 families and 15 orders. The avifauna was dominated by broadly distributed Oriental–Palearctic species, reflecting the pronounced biogeographic transition of southwestern Yunnan. Functional diversity (FD) and phylogenetic diversity (PD) differed significantly among habitats: wetlands exhibited the highest FD and PD, indicating strong functional and lineage overdispersion driven by high environmental heterogeneity, whereas farmland showed the lowest FD and PD, consistent with stronger environmental filtering. Seasonal dynamics also shaped community structure, with the highest individual abundance in winter and the lowest species richness in spring. Standardized effect sizes (SES) revealed an overall tendency toward functional and phylogenetic clustering (SES < 0), most pronounced in forest and urban communities, while wetland assemblages consistently showed greater overdispersion across seasons. Risk evaluation indicated that low-risk species comprised 76.35% of the fauna, whereas high and very-high risk species accounted for only 3.38%, mainly large raptors (Accipitriformes) and pelicans/herons (Pelecaniformes). Integrating community patterns with risk distribution, we propose zone-specific management: remove standing water and tall grass in wetlands and farmland; optimize vegetation structure along forest–urban edges; and adopt acoustic/visual deterrents and dynamic management within core airport areas to reduce strike risk. Our findings provide a comprehensive baseline of airport bird diversity and bird-strike risk in southwestern China, offering evidence-based guidance for airport ecological safety management and regional biodiversity conservation. Full article

Wastewater generated by academic institutions poses an environmental burden due to its composition, including household, food-related waste, and potential microcontaminants such as pharmaceutical and laboratory chemicals. This study evaluated wastewater from eleven academic institutions. Horizontal subsurface flow constructed wetlands (HSFCWs) filled with locally sourced volcanic gravel were tested for treatment performance at a selected site, the University of Rwanda, College of Science and Technology (UR-CST). Six HSFCWs operated continuously for four months: two planted with Cyperus latifolius, two with Juncus effusus, and two unplanted. Academic wastewater showed average concentrations of 715 mg/L COD, 54 mg/L NH₄⁺-N, 9 mg/L NO₃⁻-N, and 32 mg/L PO₄³⁻-P. A 4-day hydraulic retention time was effective for the treatment process. The HSFCWs achieved removal efficiencies of 69–82% (COD), 66–87% (NH₄⁺-N), 69–90% (NO₃⁻-N), and over 90% for TSS and PO₄³⁻-P, emphasizing the strong physical and chemical purification capacity of volcanic gravel as confirmed by XRF analysis. Juncus effusus outperformed Cyperus latifolius in biomass (6667 vs. 4389 g/m²) and nutrient assimilation per unit area, removing 3.75× more TP and 1.46× more TN. The desorption capacity of the substrate enabled potential phosphorus recovery of up to 50%. Volcanic gravel-based CWs offer an effective, low-cost, and sustainable approach to wastewater treatment with potential for nutrient recovery. Full article

Identifying the key drivers of plant community turnover under disturbance is essential for understanding ecological processes and informing conservation efforts. We investigated the Kangxi Grassland in the Yeyahu Wetland Nature Reserve, Beijing, using Generalized Dissimilarity Modeling (GDM) across two spatial scales and three areas, integrating soil properties, remote sensing data, and geographic distance. The models explained 25–49% of the deviance with low cross-validation error, showing a clear nonlinear turnover pattern. Pronounced species replacement occurred at short ecological distances, followed by slower change at greater distances. Although the overall patterns were similar, driver importance varied among areas: available nitrogen (AN) dominated in the Southeast Area, while soil water content (SWC) was the primary driver in the Northwest Area and across the entire Study Area; in all cases, geographic distance consistently ranked second. Texture indices, although weaker than geographic distance, still outperformed most vegetation indices and spectral bands. These results indicate that soil properties, geographic distance, and texture indices jointly shape spatial patterns of species turnover, with their relative importance varying by scale or area. Disturbances, such as drought, grazing, tourism, and fluctuations in inundated areas caused by variations in water levels in a nearby reservoir, influenced species turnover by directly or indirectly altering key drivers. In combination with a comparative analysis of species importance values (IVs) and ecological types, this study further demonstrates that the factors driving species turnover are influenced not only by scale but also by the complex and diverse ecological processes operating at their respective scales. It also shows the applicability of GDM in analyzing fine-scale turnover patterns and the factors driving them in disturbed grasslands. Full article

The latest climate change predictions indicate that the sea level will accelerate in the coming decades as a direct consequence of global warming. This is expected to seriously threaten low-lying coastal areas worldwide, resulting in severe coastal flooding with significant socio-economic impacts, leading to the loss of coastal settlements, exploitable land, and natural ecosystems. The main objective of this study is to provide a first-order preliminary estimation of potential inundation extents along the northern coastline of the Amvrakikos Gulf, a deltaic complex formed by the Arachthos, Louros, and Vouvos rivers in Western Greece, resulting from long-term sea-level rise induced by climate change, using the integrated Bathtub and Hydraulic Connectivity (HC) inundation method. A 2 m resolution Digital Elevation Model (DEM) was used, along with local long-term sea-level projections, for the years 2050 and 2100. Additionally, subsidence rates due to the compaction of deltaic sediments were taken into account. To assess the area’s proneness to inundation caused or enhanced by sea-level rise, the extent of each land cover type, the Natura 2000 Network protected area, the settlements, the total length of the road network, and the cultural assets located within the inundation zones under each climate change scenario were considered. The analysis revealed that under the optimistic SSP1-1.9 scenario of the Intergovernmental Panel on Climate Change (IPCC), areas of 40.81 km² (min 20.34 km², max 63.55 km²) and 69.10 km² (min 41.75 km², max 88.02 km²) could potentially be inundated by 2050 and 2100, respectively. Under the pessimistic SSP5-8.5 scenario, the inundation zone expands to 42.56 km² (min 37.05 km², max 66.31 km²) by 2050 and 84.55 km² (min 67.54 km², max 116.86 km²) by 2100, affecting a significant portion of ecologically valuable wetlands and water bodies within the Natura 2000 protected area. Specifically, the inundated Natura 2000 area is projected to range from 37.77 km² (min 20.30 km², max 46.82 km²) by 2050 to 50.74 km² (min 38.71 km², max 62.84 km²) by 2100 under the SSP1-1.9 scenario, and from 39.34 km² (min 34.53 km², max 49.09 km²) by 2050 to 60.48 km² (min 49.73 km², max 82.5 km²) by 2100 under the SSP5-8.5 scenario. Four settlements with a total population of approximately 800 people, as well as 32 economic facilities most of which operate in the secondary and tertiary sectors and are small to medium-sized economic units, such as olive mills, farms, gas stations, spare parts stores, construction companies, and food service establishments, are expected to experience significant exposure to coastal flooding and operational disruptions in the near future due to sea-level rise. Full article