Search Results (171)

The global decline in biodiversity, mainly caused by human activities such as land use change, agricultural intensification, habitat degradation, and climate change, is impacting many species, including raptors. The lesser kestrel (Falco naumanni), a threatened colonial raptor strongly associated with traditional agricultural landscapes, has experienced marked distributional and demographic changes across Spain. Understanding the environmental and anthropogenic factors shaping its occurrence is essential for guiding effective conservation actions. In this study, we combined national-scale presence data with local breeding information to identify the main drivers influencing the species’ spatial patterns and potential causes of local population change. Nationally, the lesser kestrel showed positive associations with prey availability, grasslands, and non-irrigated croplands, while urban areas, water bodies, and higher altitudes negatively affected its occurrence. Climatic variables, particularly precipitation during the warmest quarter and temperature seasonality, were also significant predictors. At the local scale (Córdoba province), colony abundance increased in non-irrigated agricultural areas and certain human-modified habitats, but declined in woodlands, open natural areas, and landscapes characterised by larger patch sizes. Overall, our findings highlight the relevance of preserving heterogeneous, traditional agricultural mosaics and maintaining prey-rich open habitats. By integrating national and local perspectives, this study identifies priority areas for conservation and provides actionable insights to support efforts aimed at halting the decline of the lesser kestrel in Spain. Full article

Symplocos is an ecologically important genus that plays vital roles in subtropical evergreen broad-leaved mountain forests, including contributing to nutrient cycling, providing shelter and habitats for various organisms, and supporting overall plant diversity across East and Southeast Asia. Many species exhibit high levels of endemism and sensitivity to environmental change. China, with its wide range of ecosystems and climatic zones, is home to 18 endemic Symplocos species. Studies revealed that global warming is driving shifts in species diversity, particularly in mountains. Our study explores the current and projected richness patterns of endemic Symplocos species in China under climate change scenarios, emphasizing the implications for conservation planning. We applied stacked species distribution models (SSDMs), using key bioclimatic and environmental variables to predict current and future habitat suitability for endemic Symplocos species, evaluated model performance through multiple accuracy metrics, and generated ensemble projections to assess richness patterns under climate change scenarios. To assess the spatial configuration and fragmentation patterns of the endemic species richness under current and future climate scenarios, landscape metrics were calculated based on classified richness maps. The produced models demonstrated high accuracy with AUC > 0.9 and TSS > 0.75, highlighting the critical role of bioclimatic variables, particularly precipitation and temperature, in shaping endemic Symplocos distribution. Our analysis identifies the current hotspots of Symplocos endemism along southeastern China, particularly in Zhejiang, Fujian, Jiangxi, Hunan, southern Anhui, and northern Guangdong and Guangxi. These areas are at high risk, with up to 35% of endemic Symplocos species richness predicted to be lost over the next 60 years due to climate change. The study predicts a high decrease in endemic Symplocos species richness, especially in South China (e.g., Fujian, Guangdong, Guizhou, Yunnan, southern Shaanxi), and mid-level decreases in East China (e.g., Heilongjiang, Jilin, eastern Inner Mongolia, Liaoning). Conversely, potential increases in endemic Symplocos species richness are projected in northern and western Xinjiang, western Tibet, and parts of eastern Sichuan, Guangxi, Hunan, Hebei, and Anhui, suggesting these regions may serve as future refugia for endemic Symplocos species. The analysis of the landscape structure and configuration revealed relatively minor but notable variations in the spatial structure of endemic Symplocos richness patterns under current and future climate scenarios. However, under the SSP585 scenario by 2080, the medium richness class showed a more pronounced decrease in aggregation index and increase in number of patches relative to other richness classes, suggesting that higher emissions may drive fragmentation of moderately rich areas, potentially isolating populations of Symplocos. These structural changes suggest a potential reduction in habitat quality and connectivity, posing significant risks to the persistence of endemic Symplocos populations, which underscores the urgent need for targeted smart-climate conservation strategies that prioritize both current hotspots and potential future refugia to enhance the resilience of endemic Symplocos forests and their ecosystems in the face of climate change. Full article

Understanding how urbanisation shapes species distributions and ecological interactions requires long-term, spatially structured data. Using an exceptionally rare 40-year dataset (1986–2025) from 150 habitat patches and 102 downtown grid cells in St. Petersburg, Russia, we examined patterns in birch (Betula pendula and B. pubescens) persistence, ground conditions, woody vegetation, and the occurrence of Eriocrania leaf-mining moths. Birch presence, birch abundance, and ground quality declined both toward the city centre and over time, whereas woody plant cover showed no clear spatial or temporal pattern. Eriocrania occurrence within birch-containing patches was influenced primarily by habitat type, artificial ground, and birch abundance, while distance to the city centre, year, and woody cover exerted no consistent effects. Habitat characteristics offered only moderate predictive power for local extinction risk in both birches and Eriocrania, indicating that multiple drivers interact to shape patch dynamics. Contrary to the widespread declines observed in many insect taxa, Eriocrania populations exhibited no directional density trend across four decades. This long-term stability highlights the resilience of specialised herbivores in heterogeneous urban landscapes and underscores the value of extended temporal datasets for detecting subtle or unexpected ecological responses to urbanisation. Full article

Based on the two-dimensional reaction–diffusion model, the spatiotemporal dynamical characteristics of the semi-discrete pine–Monochamus alternatus system with cross-diffusion and convection effect were studied in this work. Firstly, the stability conditions of the equilibrium point were obtained through linear stability analysis and Lyapunov coefficients, as well as the Andronov–Hopf bifurcation, which explained the reason for the periodic outbursts of the Lyapunov population from a dynamic perspective. Subsequently, through the characteristic equations of the Laplace operator ${\mathrm{\nabla }}^2$ and the gradient operator ∇, the critical discrimination conditions for the occurrence of Turing instability in the system were obtained and revealed that the phenomenon of frequent damage to pine caused by the pink Monochamus is in the form of patches. Finally, the reliability of the theoretical analysis was verified through numerical simulation, and the dual effect of convection was clearly found in the system. Moderate convection can change the pattern shape, while strong convection produces a “washout effect”, completely inhibiting the formation of the pattern. This indicates that factors such as wind or the directional migration of Monochamus alternatus significantly affect the spatial distribution pattern of pests. Therefore, the theoretical research on Turing instability of models with convection terms may provide inspiration for subsequent studies. Full article

Turnouts represent a critical element of railway infrastructure, and are subjected to some of the highest mechanical stresses due to the discontinuity of the track geometry. Failures in this area generate high maintenance costs and may compromise traffic safety. This study investigates the effect of wheel profile geometry on the wheel–turnout interaction in the presence of multi-point contact. Two standard wheel profiles, S78 and S1002, are compared using numerical simulations based on Kalker’s three-dimensional rolling contact theory, implemented in the CONTACT program. The methodology includes parametric analysis of the contact stresses, adhesion/slip distribution, and frictional power density for typical operational conditions. It was observed that the choice of wheel profile significantly influences the shape and load distribution of contact patches, with direct implications for wear mechanisms and guidance safety. These findings provide valuable insight for optimizing wheel–rail interface design and for reducing turnout maintenance costs. Full article

Blue-green space patterns and meteorological conditions jointly influence PM_2.5 concentrations. However, the nonlinear mechanisms and interactions among these key drivers remain insufficiently studied. To address this gap, this study applied an interpretable machine learning approach (XGBoost-SHAP) to detect seasonal nonlinearities, thresholds, and interaction effects of meteorological and landscape metrics on PM_2.5 distribution in Jiangsu Province, China. Structural Equation Model was further employed to quantify the direct and indirect effect pathways among these factors. Model explanatory power showed distinct seasonal variations, with the highest performance in summer (R² = 0.615) and the lowest in winter (R² = 0.316). Meteorological factors exerted stronger influences than blue-green space pattern metrics, with wind speed being the most critical meteorological factor across all seasons. Among landscape metrics, the proportion of green space and water body (G_PLAND and W_PLAND) was the key driver of PM_2.5 concentrations in spring, autumn, and winter, while its influence became insignificant in summer, replaced by the number and shape complexity of green space patches. This study further revealed that in spring, autumn, and winter, G_PLAND and W_PLAND not only exerted direct effects on PM_2.5 but also significantly influenced it indirectly by modulating land surface temperature. Additionally, green space shape complexity and land surface temperature were found to interact with other meteorological and landscape factors during these seasons; once exceeding specific thresholds, they reversed the direction of other factors’ effects on PM_2.5. No significant interactions were detected in summer, indicating that dominant factors primarily exerted independent effects during this season. Collectively, our findings provide important insights for formulating seasonally adaptive planning strategies to advance sustainable urban development and long-term air quality management. Full article

The construction of urban ecological security patterns (ESPs) is an effective approach for managing ecological space and preventing the uncontrolled expansion of urban areas, thereby safeguarding the ecological security of urban agglomerations. This study focuses on the Changsha–Zhuzhou–Xiangtan Urban Agglomeration (CZTUA), utilizing an ESP framework based on ecosystem services, ecological sensitivity, landscape connectivity, and resistance surfaces (SSCR). The spatio-temporal evolution and driving forces of ESP were analyzed for 2010, 2015, and 2020. Based on this, the ecological control zones of the CZTUA were delineated according to ecosystem importance, and appropriate ecological improvement strategies were proposed. The findings revealed the following: (1) The number of ecological sources in the CZTUA decreased from 26 to 23, while their total area expanded from 1113.6 km² to 3013.96 km², indicating a “point-to-patch” development trend. Ecological corridors showed a “decrease–increase”trend in number, but their total length consistently contracted from 1025.69 km to 536.25 km, with greater emphasis on the efficiency and effectiveness of connecting habitats. Ecological nodes decreased from 14 to 5, while their aggregate area increased from 290.6 km² to 1796.48 km², mirroring changes in ecological sources. (2) Ecological sources, corridors, and nodes in the CZTUA are primarily located in the eastern mountainous and hilly regions, with a trend of expansion toward the western areas. The spatial distribution of corridors and nodes is shaped by these sources, with dense areas exhibiting short-distance networks and dispersal areas showing long-distance linear patterns. Node distribution shifts from entry/exit areas of ecological sources and corridors to the sources themselves. (3) The spatio-temporal evolution of the ESP in the CZTUA is driven by a dual-wheel mechanism of “natural foundation-policy regulation,” where precipitation and potential evapotranspiration serve as the primary natural drivers, manifested through water conservation. (4) The region is divided into three control levels: the core protected areas focus on ecological protection in the eastern mountainous and hilly regions; the ecological buffer areas emphasize ecological coordination in transitional landforms such as hills, medium-undulating mountains, and platforms; the intensive development areas, mostly located in platform, plain, and some hilly areas, prioritize ecological optimization. The three-tier control zones implement strategies of strict protection, buffering and coordination, and optimized development, respectively, providing a direct basis for the refined management of ecological spaces. Full article

Ethnic villages are a multidimensional interactive space between cultural inheritance and modernization; analyzing their spatial reconstruction is fundamental for promoting agricultural and rural modernization and sustainable ethnic development. This study examined ethnic villages in Yongcong Township, Liping Country, from 2016 to 2022, focusing on changes in function and suitability under relocation through a function and suitability evaluation index. Case comparisons were made between administrative villages with high functional and suitability levels and those with resettlement sites. In 2016, ethnic villages followed a growth pattern of Yongcong–Dundong–Guantuan, with low patch density, dispersed distribution, and simple shapes. By 2022, functionality and suitability significantly improved, with an increase in village patches and larger patch areas shifting toward spatial aggregation. Horizontally, land use within reconstruction boundaries diversified by function, whereas vertically, housing structures were reorganized: non-settlement villages retained traditional and modern types while settlement villages combined both, leading to a shift from functional singularity to multifunctionality. Relocation-induced reconstruction may lag local knowledge systems and reduce well-being. Initially, government-led suitability enhancement dominates; gradually, villages increasingly internalize regional identity and competitiveness. By analyzing post-relocation village reconstruction, this study supports the integration of ethnic and regional dynamics, achieving high-quality sustainable development in minority regions. Full article

As the driving force of China’s green development, cities play a pivotal role in carbon sequestration, with their green and blue spaces jointly influencing both carbon sequestrations and carbon emissions. Yet, most existing studies rely on linear analyses, limiting the capture of nonlinear characteristics and overlooking cross-city differences in spatial configurations. Variations in spatial structures, morphology, and distribution of blue–green spaces may lead to divergent sequestration mechanisms, highlighting the need for comparative research. This study selects five high-density cities in the middle and lower Yangtze River Basin (2000, 2010, 2020) as case studies. Using the XGBoost-SHAP model, we investigate the correlations between blue–green space patterns and carbon sequestration benefits across cities. Results show that key indicators vary by city: patch shape complexity, patch area, and connectivity significantly affect sequestration benefits across all cases, while patch proximity, size, shape, and spatial aggregation matter in specific cities. This study provides a reference for optimizing urban blue–green space configurations from the perspective of carbon sequestration benefits and offers a direction for further exploration of their underlying mechanisms. At the planning level, the study identifies key indicators influencing carbon sequestration across different urban forms, providing a scientific basis for context-specific optimization of blue–green space structures and for promoting low-carbon and resilient urban development. Full article

In-depth exploration of the spatial heterogeneity patterns of urban carbon emissions holds significant scientific importance for regional sustainable development. However, few scholars have examined the spatiotemporal characteristics of county-level carbon emissions in Inner Mongolia. This study focuses on the three major cities of Hohhot, Baotou, and Ordos in Inner Mongolia. By integrating NPP-VIIRS nighttime light data, the CLCD (China Land Cover Dataset) dataset, and statistical yearbooks, it quantifies county-level carbon emissions and establishes a spatiotemporal analysis framework of urban morphology–carbon emissions from 2013 to 2021. Six morphological indicators—Class Area (CA), Landscape Shape Index (LSI), Largest Patch Index (LPI), Patch Cohesion Index (COHESION), Patch Density (PD), and Interspersion Juxtaposition Index (IJI)—are employed to represent urban scale, complexity, centrality, compactness, fragmentation, and adjacency, respectively, and their impacts on regional carbon emissions are examined. Using a geographically and temporally weighted regression (GTWR) model, the results indicate the following: (1) from 2013 to 2021, The high-value areas of carbon emissions in the three cities show a clustered distribution centered on the urban districts. The total carbon emissions increased from 20,670 (10⁴ t/CO₂) to 37,788 (10⁴ t/CO₂). The overall spatial pattern exhibits a north-to-south increasing gradient, and most areas are projected to experience accelerated carbon emission growth in the future; (2) the global Moran’s I values were all greater than zero and passed the significance tests, indicating that carbon emissions exhibit clustering characteristics; (3) the GTWR analysis revealed significant spatiotemporal heterogeneity in influencing factors, with different cities exhibiting varying directions and strengths of influence at different development stages. The ranking of influencing factors by degree of impact is: CA > LSI > COHESION > LPI > IJI > PD. This study explores urban carbon emissions and their heterogeneity from both temporal and spatial dimensions, providing a novel, more detailed regional perspective for urban carbon emission analysis. The findings enrich research on carbon emissions in Inner Mongolia and offer theoretical support for regional carbon reduction strategies. Full article

In promoting the “dual-carbon goals” and sustainable development strategy, analyzing the spatio-temporal response mechanism of landscape patterns to carbon emissions is a critical foundation for achieving carbon emission reductions. However, existing research primarily targets urbanized zones or individual ecosystem types, often overlooking how landscape pattern affects carbon emissions across entire watersheds. This research examines spatial–temporal characteristics of carbon emissions and landscape patterns in China’s Yellow River Basin, utilizing Kernel Density Estimation, Moran’s I, and landscape indices. The Geographically and Temporally Weighted Regression model is used to analyze the impact of landscape patterns and their spatial–temporal changes, and recommendations for sustainable low-carbon development planning are made accordingly. The findings indicate the following: (1) The overall carbon emissions show a spatial pattern of “low upstream, high midstream and medium downstream”, with obvious spatial clustering characteristics. (2) The degree of fragmentation in the upstream area decreases, and the aggregation and heterogeneity increase; the landscape fragmentation in the midstream area increases, the aggregation decreases, and the diversity increases; the landscape pattern in the downstream area is generally stable, and the diversity increases. (3) The number of patches, staggered adjacency index, separation index, connectivity index and modified Simpson’s evenness index are positively correlated with carbon emissions; landscape area, patch density, maximum number of patches, and average shape index are negatively correlated with carbon emissions; the distribution of areas positively or negatively correlated with average patch area is more balanced, while the spread index shows a nonlinear relationship. (4) The effects of landscape pattern indices on carbon emissions exhibit substantial spatial heterogeneity. For example, the negative impact of landscape area expands upstream, patch density maintains a strengthened negative effect downstream, and the diversity index shifts from negative to positive in the upper reaches but remains stable downstream. This study offers scientific foundation and data support for optimizing landscape patterns and promoting low-carbon sustainable development in the basin, aiding in the establishment of carbon reduction strategies. Full article

Cold-climate cities remain poorly studied, yet their spontaneous flora is strongly shaped by severe winters and short growing seasons. Heilongjiang Province, the northernmost region of China, provides a valuable case study given its rapid urbanization. As an important component of urban biodiversity, the diversity distribution patterns of spontaneous plants and their underlying causes remain underexplored from multi-scale and multi-dimensional perspectives. Therefore, this study aimed to test how climatic subzones and habitat types jointly influence spontaneous plant diversity across urban landscapes in 14 cities of Heilongjiang Province. Based on vegetation surveys, we applied calculations of α- and β-diversity, along with hierarchical clustering, across climatic subzones, cities, and habitat types to elucidate the diversity patterns and their multi-scale driving mechanisms. The results showed the following: (1) A total of 778 spontaneous plant species were recorded, belonging to 98 families and 395 genera. Native plants accounted for 58.7%, and non-native plants accounted for 41.3% (including 77 invasive species). (2) Perennial herbs dominated overall (45.2%), consistent with winter filtering, whereas annual/biennial herbs were more common in warmer subzones such as II B2. (3) Forest gaps (FG) and shrub–grassland gaps (SG) supported the most diverse spontaneous plant communities, highlighting habitat heterogeneity. (4) Species richness peaked in subzone II B2 and was lowest in subzone I A1, while abandoned land (SA) and shrub–grassland gaps (SG) supported the richest communities. (5) β-diversity analyses indicated homogenization under extreme cold in subzone I A1 and greater turnover in warmer subzone II B2, reflecting contrasting climatic filters. The “light patches” in FG habitats and the “disturbance filtering” in LA habitats further shaped the differences in local communities. This study reveals the diversity distribution patterns and adaptation strategies of spontaneous plants in cold cities, emphasizing their integration into urban planning while addressing the dominance of invasive species. Full article

Predicting how vegetation–debris interactions reshape alternate sandbars under a steady subcritical flow remains poorly understood in laboratory-to-field scaling. This study quantified how vegetation density and layout interact with debris geometry to control scouring and deposition and developed an empirical tool to predict normalized bed-level changes. Flume experiments investigated how vegetation–debris interactions regulate the hydromorphodynamics of non-migrating alternate sandbars under a steady subcritical flow (Q = 0.003 m³/s; slope = 1/200). Vegetation patches were configured in two spatial layouts—upstream (apex) and river line (edge), at varying densities, with and without debris (I-type: wall-like; U-type: horseshoe-shaped). Results indicated that dense upstream vegetation combined with I-type debris produced the strongest morphodynamic response, generating maximum scour, corresponding to the maximum bed-elevation changes (Δz) normalized by water depth (h) (dimensionless Δz/h) values of −1.55 and 1.05, and sustaining more than 70% of the downstream morphodynamic amplitude. In contrast, U-type debris promoted distributed deposition with a milder scour, while sparse vegetation yielded weaker, more transient responses. Debris geometry-controlled flow partitioning: the I-type enhanced frontal acceleration, whereas the U-type facilitated partial penetration and redistribution. To integrate these findings into predictive frameworks, an empirical regression model was developed to estimate Δz/h from the vegetation density, distribution, and debris geometry, with an additional blockage index to capture synergistic effects. The model achieved 87.5% prediction within ±20% error, providing a practical tool for anticipating scour and deposition intensity across eco-hydraulic configurations. These insights advance intelligent water management by linking morphodynamic responses with predictive modeling, supporting flood-resilient river engineering, adaptive channel stability assessments, and nature-based solutions. Full article

Wetlands function as crucial transitional zones between land and water ecosystems worldwide, contributing significantly to the stability of local ecosystems. However, there is limited research on landscape changes in Xinjiang’s arid interior regions and the factors driving these changes. This study uses data reanalysis techniques to examine the spatial and temporal evolution and landscape patterns of wetlands, as well as their driving forces, in Xinjiang between 1990 and 2023. The results show that over the past three decades, the wetland area in Xinjiang has grown from 18,427 km² in 1990 to 21,532 km² in 2023, with an annual increase of about 94 km². The greatest growth in wetlands, particularly lakes, marshes, and rivers, has occurred around the periphery of the Tarim Basin and the Ili River Basin, while mountainous areas have seen slight reductions. The distribution pattern shows higher wetland coverage in southern Xinjiang and less coverage in the north, with the largest proportion of wetlands found in the south. Additionally, wetland expansion has led to improvements in the number, density, aggregation, and connectivity of wetland patches, while the complexity of their shapes has decreased. The overall habitat quality of wetlands has also improved over time. Attribution analysis highlights that the rise in runoff due to temperature increases over the past 30 years is a major driver of wetland expansion, with warming accounting for the largest share of expansion in lakes (36%) and in rivers (47.9%). Furthermore, the implementation of large-scale engineering measures, such as ecological water diversion, water-saving irrigation, and reservoir management, has contributed significantly to wetland expansion and ecological restoration. These results provide useful insights for the long-term conservation and management of wetland resources in the arid areas of Xinjiang. Full article

Nowadays, attempts to commercially apply non-pneumatic tires (NPTs) in a wide range of vehicles can be observed. These types of wheels use a specific structure and material selection to mimic the function of compressed air in pneumatic tires (PTs). This paper reviews the mechanical properties and vehicle applications of non-pneumatic tires. This review will provide information about the influence of the shape of the radial, longitudinal, and lateral characteristics, as well as the possibility of selecting contact pressure values at the wheel design stage and the influence of the type of elastic structure on the concentration of pressures in the contact length. The radial characteristics of non-pneumatic tires depend on the type of elastic structure. The spoked elastic structure will be characterized by greater displacements compared to the cellular structure, which will reduce radial stiffness. The radial stiffness of non-pneumatic tires is increased by increasing the number of elastic structure elements and their thickness and decreasing their length. The longitudinal stiffness of non-pneumatic tires increases with the number of elements forming the elastic structure and with the elastic structure’s lack of susceptibility to circumferential deformation. Spoked non-pneumatic tires will have lower longitudinal stiffness compared to cellular non-pneumatic tires. The elastic structure is characterized by a low susceptibility to lateral deformation, which contributes to the high lateral stiffness of the non-pneumatic tire. Non-pneumatic tires have a limited ability to shape the contact patch parameters, which mainly depend on the vertical load and the shape of the tread area. The type of band used will influence the formation of contact pressures. An isotropic elastomer used in a shear band will cause pressure concentration at the ends of the contact length. A more uniform pressure distribution is achieved by using a laminated elastomer. Full article