Search Results (1,429)

Air quality in the Po Valley (Northern Italy), one of Europe’s most polluted regions, remains a major concern due to its unfavorable orographic setting and intense anthropogenic emissions. Climate change may further hinder progress by modifying meteorological conditions that regulate pollutant dispersion and chemistry. This study applies a modeling framework combining regional climate simulations and chemical transport models to assess the climate penalty, i.e., the adverse impact of climate-driven meteorology on air quality independent of emissions. Three scenarios were analyzed: Baseline Reference Scenario (SRB) (2011–2015), Near-Future Medium Scenario (NF) (2028–2032), and Mid-Future Medium Scenario (2048–2052), with emissions held constant. A mitigation scenario (SC_MF_2050) under the Current Legislation was also tested to accomplish the new EU Ambient Air Quality Directive. Results show that PM₁₀ and NO₂ increase under future climates, mainly due to reduced wind speed and precipitation, enhancing pollutant accumulation. Multivariate analyses confirm the strong association between stagnant conditions and higher concentrations. Even with projected emission reductions, compliance with stricter EU targets may not be achieved everywhere. Climate penalty zones, especially in lowland and transport corridors, underscore the need to integrate climate resilience into air quality planning and adopt adaptive strategies for long-term effectiveness. Full article

Disaster risk reduction requires efficient flood control in lowland and flood-prone areas, especially in agricultural areas like the Bang Rakam model area in Phitsanulok province, Thailand. In order to improve flood prediction and response, this study proposes the creation of a low-cost, real-time water-level monitoring integrated with spatial data analysis using Geographic Information System (GIS) technology. Ten ultrasonic sensor-equipped monitoring stations were installed thoughtfully around sub-catchment areas to provide highly accurate water-level readings. To define inundation zones and create flood depth maps, the sensors gather flood level data from each station, which is then processed using a 1-m Digital Elevation Model (DEM) and Python-based geospatial analysis. In order to create dynamic flood maps that offer information on flood extent, depth, and water volume within each sub-catchment, an automated method was created to use real-time water-level data. These results demonstrate the promise of low-cost IoT-based flood monitoring devices as an affordable and scalable remedy for communities that are at risk. This method improves knowledge of flood dynamics in the Bang Rakam model area by combining sensor technology and spatial data analysis. It also acts as a standard for flood management tactics in other lowland areas. The study emphasizes how crucial real-time data-driven flood monitoring is to enhancing early-warning systems, disaster preparedness, and water resource management. Full article

Wildfire behavior and post-fire effects are strongly modulated by terrain, yet the relative influence of individual topographic factors on burn severity remains incompletely quantified at landscape scales. The Composite Burn Index (CBI) provides a field-calibrated measure of severity, but large-area analyses have been hampered by limited plot density and cumbersome data extraction workflows. In this study, we paired 6150 CBI plots from 234 U.S. wildfire events (1994–2017) with 30 m SRTM DEM, extracting mean elevation, slope, and compass aspect within a 90 m buffer around each plot to minimize geolocation noise. Topographic variables were grouped into ecologically meaningful classes—six elevation belts (≤500 m to >2500 m), six slope bins (≤5° to >25°), and eight aspect octants—and their relationships with CBI were evaluated using Tukey HSD post hoc comparisons. Our findings show that all three factors exerted highly significant influences on severity (p < 0.001): mean CBI peaked in the 1500–2000 m belt (0.42 higher than lowlands), rose almost monotonically with steepness to slopes > 20° (0.37 higher than <5°), and was greatest on east- and northwest-facing slopes (0.19 higher than south-facing aspects). Further analysis revealed that burn severity emerges from strongly context-dependent synergies among elevation, slope, and aspect, rather than from simple additive effects. By demonstrating a rapid, reproducible workflow for terrain-aware severity assessment entirely within GEE, the study provides both methodological guidance and actionable insights for fuel-management planning, risk mapping, and post-fire restoration prioritization. Full article

Tibetan sheep are an important livestock breed adapted to the extreme environment of the Qinghai–Tibet Plateau (QTP). Their energy metabolism and environmental adaptability are highly dependent on the rumen microbiome. However, systematic comparisons of the rumen microbiome, its functions, and the resistome between plateau-adapted breeds and lowland breeds remain insufficient. In this study, 6 Tibetan sheep (TS) and 6 Hu sheep (HS) were selected. All the selected sheep had a body weight of 34 kg (±0.5 kg) and an age of 1 year (±1 month) and were all managed under local traditional natural grazing (without supplementary feeding). Using metagenomics and metabolomics techniques, systematic comparative analysis was conducted on the differences in rumen microbial community structure, functions, resistome, and metabolites between the two breeds. Metagenomic analysis showed that at the phylum level, the abundance of Bacteroidetes in the rumen of TS was significantly higher than that in HS (p < 0.05); at the genus level, the abundance of Bacteroides in TS was also significantly higher (p < 0.05). Carbohydrate-active enzymes (CAZy) analysis indicated that the abundance of Glycosyltransferases (GTs) and Carbohydrate-Binding Modules (CBMs) in the rumen of TS were significantly upregulated (p < 0.05), while HS was rich in various Glycoside Hydrolases (GHs). Comprehensive Antibiotic Resistance Database (CARD) analysis revealed that more than 60% of the Antibiotic Resistance Genes (ARGs) in the rumen of HS were present at higher levels than those in TS. Metabolomics identified a large number of differential metabolites, among which metabolites such as 2E,6Z,8Z,12E-hexadecatetraenoic acid, Leukotriene F4, and Tenurin were significantly upregulated in the rumen of TS. Correlation analysis showed that rumen microbial flora and their metabolites jointly act to regulate rumen ARGs. Specifically, microorganisms including Firmicutes and Succiniclasticum had a significantly positive correlation with ARGs such as rpoB2 (p < 0.05), while differential metabolites like endomorphin-1 and Purothionin AII exhibited a significantly negative correlation with ARGs such as rpoB2 (p < 0.05). Therefore, compared with HS, the synergistic effect of the rumen microbial flora, their metabolites, and the resistome in TS is an important characteristic and strategy for their adaptation to the hypoxic environment of the QTP, and also contributes to the formation of their unique rumen resistome. Despite being reared in the same plateau environment, the rumen microbiome of HS still retains low-altitude characteristics, which are manifested as high GHs activity and high ARGs abundance. Full article

Excessive nitrogen export from lowland polders is a key contributor to cultural eutrophication in downstream aquatic ecosystems. This study investigated the spatiotemporal characteristics, migration pathways, and sources of nitrogen pollution in a typical polder system. Eight surface water sampling campaigns were conducted at 13 sites in Quyuan Polder, Dongting Lake, from 2022 to 2023, combining ArcGIS spatial analysis, multivariate statistics, and dual-isotope (δ¹⁵N-NO⁻), δ¹⁸O-NO₃⁻) techniques. Nitrate and ammonium nitrogen dominated the nitrogen pool, accounting for ~76% of total nitrogen. Concentrations were higher in the dry season (2.48 mg/L) than in the wet season (1.89 mg/L) and differed significantly among hydrological periods (p < 0.05). Within the polder, total nitrogen and ammonium nitrogen were elevated, whereas nitrate nitrogen was higher at the outlet, reflecting distinct nitrogen profiles along the hydrological gradient. Nitrogen transport patterns were largely consistent with flow direction, driven by both upstream inputs and in situ generation. Isotopic signatures indicated that nitrate originated mainly from ammonium fertilizer and soil nitrogen, with contributions from manure and sewage. These findings enhance understanding of nitrogen dynamics in lowland catchments and provide a scientific basis for targeted pollution control in polder waters. Full article

Urban forests provide many ecosystem services in urbanized landscapes, including biodiversity conservation. The sustainable management of urban forests requires a thorough understanding of biodiversity changes in the context of rapid urbanization. As biodiversity in rapidly changing urban areas is very dynamic, we need a better understanding of long-term biodiversity changes in urban forests. Birds are very good bioindicators of urban forest biodiversity because they are strongly habitat-sensitive. However, a major knowledge gap exists in long-term trends in bird diversity in temperate urban forests. This study analyzed a comparison of bird-species richness in a temperate Central European urban forest over a time span of 37 years. Bird-counts using the standard line-transect method conducted in 2023–2024 were compared with older field data from 1987 gained using the same method in a lowland hardwood floodplain forest in the Czech Republic. The results revealed significant faunistic similarities in the bird-species diversity of an urban forest during the 1987–2024 period. The high local alpha diversity of the bird community (42 nesting bird species) as well as the relatively high long-term stability in bird richness indicated the importance of the studied urban forest as a stable biodiversity refugium in a dynamic urbanized landscape. Therefore, urban forests can be considered very stable biodiversity refugia in dynamically changing urban areas. Full article

Riverbank erosion poses a significant threat to livelihoods and infrastructure in the Vietnamese Mekong Delta (VMD), necessitating innovative and sustainable solutions. This study explores the use of old tyres as a material for embankment construction to stabilize riverbanks, combining physical reinforcement with bioengineering techniques. A pilot project was conducted in Dinh My commune, An Giang Province, where an embankment was constructed using old tyres, geotextile, riprap, and vegetation. Field measurements using the Leica TS02 Plus Total Station and Finite Element Method (FEM) modeling were employed to assess the embankment’s performance. Results indicate that the embankment effectively stabilized the riverbank, with a maximum displacement of 18 mm observed after one year. The FEM predictions closely aligned with the measured data, achieving an accuracy of 68% or higher, validating the model’s accuracy. The integration of vegetation further enhanced stability, demonstrating the potential of this approach as a sustainable and cost-effective solution for riverbank protection. This study highlights the dual benefits of erosion control and waste management, offering a replicable strategy for addressing riverbank erosion across deltaic and lowland regions. The pilot offers a scalable model for climate-resilient infrastructure in deltaic regions globally, linking erosion control with circular economy strategies. Full article

Anthocyanins (ACNs) are flavonoid pigments that accumulate in plants and respond to environmental stimuli, including low phosphorus (LP). The synthesis and stable accumulation of ACNs rely on substantial carbohydrate investment, implying a potential role in carbon partitioning-mediated growth and resistance, in addition to the well-established antioxidant activity. To investigate cultivar-dependent differences in ACN accumulation and their relationship with photo-assimilate partitioning and growth adaptation under LP stress, seedlings of six representative maize cultivars were hydroponically cultured under both control and LP conditions. ACNs content, photosynthetic parameters, plant relative growth ratio, and tissue-specific carbohydrates were quantified. The results showed that LP reduced photosynthesis and biomass, while stimulating ACNs biosynthesis in leaves and sheaths. Cultivars were then classified as ACN-sensitive and -insensitive groups based on the ACNs accumulation in the newly unfolded leaves and corresponding sheaths. ACN-sensitive cultivars exhibited higher ACNs levels, which correlated positively with soluble sugars but negatively with starch reserves, suggesting preferential carbon partitioning to ACNs precursors rather than to starch. These cultivars also maintained higher relative growth ratios under LP, associated with less photosynthesis decline and starch accumulation compared with ACN-insensitive cultivars. We hypothesize that ACNs synthesis function as a diversion of photo-assimilates into secondary metabolism under LP, thereby improving photosynthetic efficiency by mitigating excess sugar accumulation that could impair plant growth. This carbon-partitioning adaptation could be exploited by selecting for ACNs accumulation as a breeding trait to enhance maize resilience to LP. Full article

Soils act as sources or sinks for three major greenhouse gases (CO₂, CH₄, and N₂O). Approximately 20% of global CO₂ emissions are released from soils through the soil respiration process. Soil respiration (soil CO₂ emission) can account for over 85% of ecosystem respiration. The aim of this study was to compare managed and unmanaged stands of pedunculate oak (Quercus robur L.) in order to investigate the impact of forest management on soil CO₂ emissions. We selected one managed and two unmanaged stands. The first stand (S1) represents a managed middle-aged stand, which is the optimal stage of development. The second stand (S2) belongs to the over-mature stage of development in an old-growth oak forest, while the third stand (S3) belongs to the decay stage of development in an old-growth oak forest. The closed chambers method was used for air sampling and the air samples were analyzed using gas chromatography (GC). Multiple regression models that include soil temperature (ST), soil moisture (SM), and their interaction provide a better explanation for variation in soil CO₂ emission (SCDE) (higher R² values) compared to regression models that only involve two variables (ST and SM). The study showed that SCDE in the decay stage of old-growth forest (S3) was significantly lower (p < 0.001) compared to the other two stands (S1 and S2). S3 is characterized by very low canopy cover and intensive natural regeneration, unlike S1 and S2. However, there were no significant differences in SCDE between the managed middle-aged stand (S1) and the over-mature (old-growth) stand (S2). Over a long-term rotation period in pedunculate oak forests, forest management practices that involve the periodic implementation of moderate silvicultural interventions can be deemed acceptable in terms of maintaining the carbon balance in the soil. Full article

Hydrological drought in Central Europe is becoming an increasingly serious threat to agriculture, industry, and people due to climate change and the rising frequency and intensity of extreme weather events. The main aim of the paper was to assess the spatial variability of streamflow drought in Poland. The spatial analysis was conducted using daily streamflow series from 340 gauging stations for the period 1973–2022. Hydrological drought was defined as a period with a streamflow lower than Q_90%. The results show that, on average, hydrological droughts occur 52 times per year at a given gauging station. Drought duration and volume depend on the gauge elevation. At higher-altitude stations, shorter and smaller-volume droughts are most commonly observed. The longest droughts are recorded in Northern Poland, particularly in the Lakeland regions, which is a serious problem mainly for the agriculture sector. Hydrological droughts in Poland most frequently begin in summer and end in late summer or early autumn. Analyses showed that hydrological drought has a strong spatial distribution, and it is possible to identify five main regions with homogeneous drought duration and volume. Trend analysis of the annual number of low-flow days indicates no statistically significant trend at 46% of stations, while 54% exhibit statistically significant increases, with marked regional variability. The highest number of stations with statistically significant decreasing trends occurs in the Southern and Eastern Baltic Lake District and in the Central Poland Lowlands and Highlands with Polesie. The study highlights the necessity of enhancing water retention, particularly in the central, lowland regions of Poland. Full article

We used stable carbon and nitrogen isotope values in plants, fur, and bone to establish baseline isotopic variability and investigate food web dynamics for small mammals at Betampona Réserve Naturelle Intégrale (BRNI), which protects an isolated parcel of tropical lowland moist evergreen forest in central eastern Madagascar. We included foliage from four understory plant genera, 13 endemic mammal species (5 bats, 5 tenrecs, and 3 nesomyine rodents), and introduced Rattus rattus and Suncus murinus that were collected along a gradient of degraded to intact forest from the southern boundary to the interior of BRNI as well as nearby villages. Isotopic data indicate niche partitioning among mammal groups, as well as among species within each of the groups. Most species appear to have foraged in the forest understory, although some, bats in particular, may have foraged outside of the protected area. We did not find evidence for competition between introduced and endemic animals but caution that some sample sizes are small. These results provide previously unknown insight into dietary preferences for some of Madagascar’s least studied mammals and establish a foundation for future work at BRNI. Full article

The Qinghai-Tibet Plateau, known as the “third pole” of the Earth with an average elevation of approximately 4500 m, offers a unique natural laboratory for probing the dynamic behavior of the global electric circuit. In this study, we conduct a comprehensive analysis of near-surface vertical atmospheric electric field (AEF) measurements collected at the Gar Station (80.1° E, 32.5° N; 4259 m a.s.l.) on the western Tibetan Plateau, spanning the period from November 2021 to December 2024. Fair-weather conditions are imposed. The annual mean AEF at Gar is ∼0.331 kV/m, significantly higher than values observed at lowland and plain sites, indicating a pronounced enhancement in atmospheric electricity associated with high-altitude conditions. Moreover, the AEF exhibits marked seasonal variability, peaking in December (∼0.411–0.559 kV/m) and valleying around July–August (∼0.150–0.242 kV/m), yielding an overall amplitude of approximately 0.3 kV/m. We speculate that this seasonal pattern is primarily driven by variations in aerosol concentration. During winter, increased aerosol loading from residential heating and vehicle emissions due to incomplete combustion reduces atmospheric conductivity by depleting free ions and decreasing ion mobility, thereby enhancing the near-surface AEF. In contrast, lower aerosol concentrations in summer lead to weaker AEF. This seasonal decline in aerosol levels is likely facilitated by stronger winds and more frequent rainfall in summer, which enhance aerosol dispersion and wet scavenging, whereas weaker winds and limited precipitation in winter favor near-surface aerosol accumulation. On diurnal timescales, the Gar AEF curve deviates significantly from the classical Carnegie curve, showing a distinct double-peak and double-trough structure, with maxima at ∼03:00 and 14:00 UT and minima near 00:00 and 10:00 UT. This deviation may partly reflect local influences related to sunrise and sunset. This study presents the longest ground-based AEF observations over the Qinghai–Tibet Plateau, providing a unique reference for future studies on altitude-dependent AEF variations and their coupling with space weather and climate processes. Full article

Temperate forest ecosystems in Korea are currently undergoing a successional transition from Pinus densiflora Siebold & Zucc. (evergreen conifer) communities to Quercus mongolica Fisch. ex Ledeb. (deciduous broadleaf) communities. This study aimed to assess interspecific differences in ecological responses to climate change [Representative Concentration Pathway (RCP) 4.5] by evaluating changes in ecological niche characteristics and species distribution. Controlled-environment experiments, principal component analysis (PCA), and MaxEnt species distribution modeling were employed to quantify and predict ecological shifts in the two dominant species under climate change scenarios. Both species exhibited increases in niche breadth and interspecific overlap under climate change conditions. However, Q. mongolica showed a more pronounced increase in niche breadth compared to P. densiflora, indicating greater ecological flexibility and adaptive potential to warming conditions. According to the MaxEnt model projections, climate change is expected to result in an approximate 30% reduction in suitable habitat for P. densiflora in lowland areas. In contrast, Q. mongolica is projected to expand its suitable habitat by over 80%, notably in both low-elevation (below 800 m) and high-elevation (above 1400 m) zones, without being restricted to any specific altitudinal range. Our findings suggest that climate change may increase ecological similarity between P. densiflora and Q. mongolica, thereby raising the potential for interspecific competition. This convergence in niche traits could contribute to an accelerated successional transition, although actual competitive interactions in natural ecosystems require further empirical validation. Consequently, Korean forests are likely to transform into predominantly deciduous forest ecosystems under future climate conditions. Full article

The cumulative impact of decades of oil and gas exploration has left Alberta’s boreal forests densely fragmented by seismic lines, which are expected to naturally regenerate; however, recovery is often highly variable and generally poor in peatlands due to increased wetness and reduced microtopography. In this study, we evaluated seismic lines in lowland ecosites with some degree of successful natural regeneration to gain a better understanding of the natural recovery process in these areas. We compared stand characteristics between the seismic line (23 to 48 years post-disturbance) and the adjacent undisturbed forest. We found that soil properties were similar, but seedling (height < 1.3 m) density was significantly higher on the seismic line, with 252% more tamarack and 65% more black spruce than in the adjacent forest. Relative to the adjacent forest, there were significantly fewer trees (height > 1.3 m) on the seismic line, with an 84% and 50% reduction in black spruce and tamarack, respectively. By analyzing tree ring data from seismic lines, we found that the length of time before tree establishment was 10 years for black spruce and 8 years for tamarack. On average, it took 12 years for tree density to reach 2000 stems per hectare (sph). We modeled growth rates for black spruce and tamarack and found that they were growing faster than their adjacent forest counterparts, reaching 3 m after an average of 38 and 33 years, respectively. Stands on seismic lines were projected to a final stand age of 61 years using the Mixedwood Growth Model (MGM) to evaluate future stand characteristics. Full article

The Nahuelbuta Mountain Range in the south-central zone of Chile is a biodiversity hotspot that has undergone intense land use/cover transformation. This study analyses two decades of land use change (1999–2018) in the watersheds of the Lebu and Leiva rivers. The magnitude and spatial configuration of these changes were assessed using detailed spatial information, transition matrices, and landscape metrics. The results show that between 1999 and 2018, temperate native forest decreased by 30.3% in Lebu and 22.8% in Leiva, being replaced mainly by exotic forest plantations, which increased by 20.2% and 13.5%, respectively. The spatiotemporal analysis revealed losses concentrated in the lowland and middle zones of both watersheds, with persistence of temperate native forest in higher elevations. Landscape metrics showed an increase in diversity (SIDI: Lebu 0.41–0.65; Leiva 0.29–0.57) and a decrease in aggregation (AI: 92–86%; 95–90%). At the class level, the temperate native forest presented greater fragmentation, with a reduction in size and proximity, an increase in density, and more irregular shapes. In contrast, exotic forest plantations increased in size and proximity, with a slight decrease in density and greater complexity of form, consolidating their expansion and spatial continuity in both watersheds. These findings emphasise the need to implement territorial planning and conservation strategies adapted to the Nahuelbuta context, through native forest management plans that promote ecological conservation, the recovery of degraded landscapes, and the strengthening of ecosystem services, thus contributing to the well-being of local communities and long-term environmental sustainability. Full article