Search Results (164)

Flooding triggered by intense precipitation is a significant natural hazard affecting Mediterranean regions, where complex terrain, rapid hydrological response and increasing urbanization can amplify flood impacts. This study assesses flood susceptibility in two representative Mediterranean River catchments: the Koiliaris in Crete, Greece, and the Pediaios in Cyprus. A compact Flood Hazard Index (FHI) was developed by integrating the Topographic Wetness Index (TWI), Curve Number (CN), and R20 heavy rain frequency index, representing the principal geomorphological, hydrological and climatological controls of flood generation. Spatial datasets including EU-DEM elevation data, CORINE land cover, European soil databases, and Copernicus CERRA precipitation reanalysis were combined within a GIS-based multi-criteria framework using Analytic Hierarchy Process weighting. The resulting FHI maps identify high flood susceptibility along river corridors, low-lying accumulation zones, and urbanized areas. In the Koiliaris basin, 34% of the area fell within the high and very high susceptibility classes, mainly in downstream alluvial zones, whereas in the Pediaios basin, 29% of the area fell within the high and very high susceptibility classes, concentrated around the urbanized Nicosia corridor. The analysis of historical flood events provided a qualitative consistency assessment of the FHI patterns, acknowledging that the absence of spatially explicit flood-inundation footprints limits quantitative validation. Full article

PM2.5 and near-surface O₃ compound pollution is a major challenge for further air quality improvement in the Yangtze River Delta (YRD). Despite research on the chemical coupling mechanisms and concentration co-variation between PM2.5 and O₃, the directional linkages of compound pollution events among cities and the network mechanisms underlying their formation remain unclear. Here, we identified PM2.5–O₃ compound pollution events for 41 YRD cities from 2015 to 2024 using city-year-specific P80 dual-threshold criteria. We then constructed annual directed synchronization networks based on event-leading relationships and used temporal exponential random graph models to identify the formation mechanisms of significant leading ties. PM2.5–O₃ compound pollution events in the YRD generally decreased during 2015–2024, with characteristics shifting from high frequency, persistence, and strong intercity linkage in the early stage to lower frequency, weaker intensity, and continued episodic fluctuations. Directed event networks exhibited a clear stage-dependent evolution: network density, total edge weight, reciprocity, and local closure were relatively high during 2015–2018, networks became markedly sparse during 2020–2022, and a partial rebound occurred after 2023. Spatial backbone analysis indicated reorganization of the dominant linkage structure, shifting from the Shanghai–southern Jiangsu–northern Zhejiang coastal core toward the northern Jiangsu, Anhui, and interprovincial corridors. Key node analysis further revealed a clear functional differentiation among cities, with some cities acting as potential leading sources, some as receiving nodes, and several non-traditional core cities serving as cross-regional bridges. Significant leading ties were jointly shaped by reciprocity, local closures, temporal memory, economic development, industrial structure, and digital governance. Therefore, as well as a problem of co-occurrence, PM2.5–O₃ compound pollution in the YRD is a cross-city event-network process characterized by directionality, stage-dependent evolution, and differentiated urban roles. This study provides empirical evidence for dynamic joint prevention and control based on event linkages, urban roles, and cross-city coordination. Full article

Post-war Aleppo is often framed through destruction, legal constraints, and the technical demands of reconstruction. This article challenges that assumption by re-reading Aleppo’s pre-2011 municipal vision as an analytical resource for post-war recovery. The study adopts a qualitative interpretive methodology based on municipal archival material, including the City Council work programme, strategic planning presentations, project documents, and materials related to the City Development Strategy, Madinatuna initiative, the old city, Bab Antakiya, and major public-space and service initiatives. The analysis followed three steps: identifying repeated municipal priorities and planning concepts; organizing them into thematic axes; and interpreting flagship projects as spatial expressions of a broader municipal vision. To assess post-war relevance, the archive is also read against evidence of damage, displacement, urban functionality, and heritage loss. The results show that Aleppo’s pre-2011 municipal vision can be reconstructed through six interrelated axes: strategic urban development and managed growth; the old city as a living urban fabric; urban repair in the city centre; mobility and accessibility; culture and social development; and development partnerships and international cooperation. The findings reveal that these axes formed a partially integrated municipal urbanism rather than isolated projects, while flagship interventions such as Bab Antakiya, the Green Path, the river corridor, and the Citadel surroundings materialized this logic. The study also finds that this vision remained institutionally vulnerable because of political centralization and limited municipal autonomy. It concludes that post-war recovery should build on critical continuity rather than reconstruction from scratch. Full article

Blue-green spaces are critical for diversified landscape planning. However, rapid urbanization and habitat fragmentation continue to disrupt ecological connectivity in river-basin landscapes. This study focuses on the Xiu River Basin, a major tributary of Poyang Lake and a key node of the East Asian–Australasian Flyway. We developed a multi-guild avian ecological network framework to support biodiversity-oriented landscape planning. Birds were classified into four functional guilds: aquatic resident, aquatic wintering, forest resident, and forest wintering. For each guild, we designed a specific set of environmental variables. We integrated MaxEnt and InVEST to identify ecological sources by combining habitat suitability with habitat quality. The results showed that 68.75% of the basin qualifies as good-quality habitat, although suitable habitats remained highly heterogeneous and fragmented among guilds. We identified 1839.93 km² of ecological sources, 157 corridors, 215 pinchpoints, and 344 barriers, revealing clear differences in the connectivity requirements between aquatic and forest birds and between resident and wintering birds. We further delineated four ecological priority areas and proposed targeted restoration strategies for wetlands, river–lake systems, forested mountains, and urban–rural transition zones. Overall, this study demonstrates that multi-guild connectivity analysis can provide a spatial framework for informing urban forest conservation, blue-green infrastructure planning, and diversified landscape planning in complex basin landscapes. Full article

Peri-urban zones are critical interfaces where urban expansion, agricultural production, and ecological processes overlap. However, ecological-network planning in these areas is often constrained by uncertain boundary definition and insufficient integration between habitat quality and landscape connectivity. Taking Zhengzhou, China, as a case study, this paper proposes a resilience-oriented Ecological Security Membrane planning framework that links peri-urban boundary delineation with the prioritization of ecological sources, corridors, and critical points. A deep neural network was used to distinguish the urban core, urban fringe, and peri-urban zone from multi-source land-use and socioeconomic indicators, achieving an overall classification accuracy of 93.1%. Priority ecological sources were then identified by coupling biodiversity quality, patch morphology, area thresholds, and connectivity contribution, while corridors and critical points were prioritized to support network reinforcement. The results reveal a peri-urban ecological structure characterized by source concentration in the western mountainous and eastern agroforestry areas, insufficient ecological continuity along the Yellow River corridor, and key bottlenecks at transport and urban-expansion interfaces. The proposed framework advances peri-urban ecological planning by translating source–corridor–node analysis into a spatially explicit planning structure. Future research should test the robustness of this framework under multi-year, multi-seasonal, and scenario-based urban-growth conditions. Full article

Intensifying climate change poses a major challenge to biodiversity conservation by weakening the ability of protected area systems to support species movement and ecological processes. However, protected area network planning has paid limited attention to the integration of climate connectivity and network resilience. Taking the highly urbanized Yangtze River Delta (YRD) as a case study, this study developed an integrated framework for climate-connected protected area network optimization. Specifically, climate refugia potential and species distribution probability were integrated to identify source areas, climate connectivity corridors were delineated by coupling landscape resistance with temperature gradients, and complex-network-based resilience analysis was applied to evaluate network responses under multiple disturbance and recovery scenarios. The results showed that: (1) climate stability, climate heterogeneity, and species distribution probability generally exhibited a south-to-north decreasing pattern, and 205 source areas were identified, mainly concentrated in the western and southern mountainous regions; (2) 459 climate connectivity corridors were extracted, forming a network backbone in the western and southern mountains, whereas corridors were relatively sparse in the plains and highly urbanized coastal areas; and (3) the network was highly vulnerable under critical-node-targeted, human-pressure-oriented, and climate-risk-oriented attack scenarios, while critical-node-priority recovery was the most effective strategy for restoring network function. These findings provide scientific support for cross-regional coordination, restoration prioritization, and long-term adaptive management in climate-connected protected area network planning. Full article

Under the dual pressures of global climate change and rapid urbanization, the spatial contradiction between urban expansion and flash flood disasters in mountainous dam areas is increasingly evident. However, the mechanisms by which the multi-dimensional characteristics of urban expansion affect regional flash flood susceptibility (FFS) remain unclear, limiting scientific guidance for source-level disaster prevention. This study uses Zhaotong City, a flash flood-prone area in the lower Jinsha River basin of southwestern China, as a case study. Using land use and multi-source remote sensing data from 2000 and 2025, we identify urban expansion patterns and morphological characteristics, apply the XGBoost-SHAP model to evaluate flash flood susceptibility and determine dominant factors, and employ the generalized additive model (GAM) to quantify the nonlinear responses of expansion dimensions to FFS. Results show the following: (1) Urban expansion in Zhaotong City is primarily edge (51%) and leapfrog (46%), clustering along river valleys, dam areas, and transportation corridors. (2) The XGBoost model performs well (AUC = 0.877). Elevation, slope, normalized difference vegetation index (NDVI), and precipitation are the primary natural factors influencing FFS. About 15.66% of the city falls within the high/very high FFS zones, mainly in the Zhaolu Dam area, riverbanks of main and tributary streams, and the urban built-up area. (3) Urban expansion-related indicators explain 28.6% of the spatial variation in FFS, with leapfrog expansion as the primary driver (contribution rate 32.75%). Disorderly urban growth and morphological imbalance significantly increase flash flood susceptibility. This study provides a scientific basis for spatial planning, flash flood prevention and control, and climate-adaptive urban development in similar mountainous dam areas in Southwest China and Asia, supporting regional sustainable development goals. Full article

Tourism safety in high altitude destinations is strongly affected by the combined effects of environmental constraints, tourism exposure, and safety support capacity. The Qinghai–Tibet Plateau (QTP), characterized by high altitude, complex terrain, sparse settlements, and limited emergency accessibility in remote areas, provides a representative case for tourism risk assessment in extreme plateau environments. To predict and interpret the spatial pattern of tourism risk on the QTP, this study constructs an assessment framework based on “Hazard–formative factors + Risk exposure + Safety security” and integrates XGBoost with SHAP interpretable machine learning. Eleven indicators representing environmental conditions, tourism exposure, and safety support capacity were used to model tourism risk at a 1 km × 1 km spatial resolution. The optimized XGBoost model achieved an AUC of 0.877, indicating good predictive performance. The results show that tourism risk on the QTP presents a spatial pattern of “high in the northwest and low in the southeast”. High risk and relatively high risk areas account for approximately 74.98% of the study area and are mainly distributed in remote hinterlands and northwestern plateau regions, whereas low risk areas are concentrated around southeastern river valleys, towns, mature scenic areas, and major transport corridors. SHAP analysis indicates that Distance to towns is the most important factor influencing predicted tourism risk, followed by Reception facility kernel density, Relief degree of land surface, and Scenic spot kernel density. Nonlinear and interaction analyses further suggest that remoteness, tourism facilities, terrain relief, and scenic area concentration jointly shape the predicted risk pattern. The findings provide spatial evidence for differentiated tourism risk management, including regular tourism development in relatively safe urban and scenic nodes, controlled management of medium risk tourism corridors, and stricter access management in remote high risk areas. Full article

Water ecosystem service flows (WESFs) help address spatial mismatches in water resources and support basin resilience. However, their dynamic evolution and nonlinear drivers under climate change and intensive human activities remain poorly understood. This study evaluates the spatiotemporal dynamics of WESFs in the Yangtze River Basin (YRB) from 2005 to 2022 by integrating dynamic flow analysis with mechanism interpretation. We developed an integrated framework coupling SWAT hydrological simulations with a proxy-based spatial allocation approach for social water demand. Using the Water Stress Index (WSI) and river topology, dynamic inter-regional WESFs were simulated. Furthermore, an interpretable machine learning approach was employed to identify the nonlinear effects of multiple driving factors. Results reveal a persistent supply–demand mismatch: supply exhibited a northwest–southeast gradient (averaging 567.21 mm annually), while demand concentrated in mid-lower plains and urban corridors. The flow network, which accounts for accumulated upstream inflow, demonstrated a stable “upstream supply, mid-reach transmission, and downstream benefit” pattern, highlighting downstream reliance on upstream inputs. Driving analysis identified land surface and vegetation as the largest associated driver category, while climate–hydrology and human activity were not cleanly separable. Climate provided the hydro-climatic conditions for redistribution. Nonlinear responses and blue–green interactions were also identified, informing transboundary ecological compensation and regional water-resilience management. Full article

Climate-driven intensification of pluvial and fluvial flooding increasingly challenges lowland cities in Central Europe, while conventional protection and land-use controls offer limited flexibility under growing hydrological variability. A planning-oriented framework is developed and tested to integrate hydro-adaptive housing into climate-resilient urban development using three typologies: elevated foundations, amphibious dwellings and modular floating platforms. The framework links hazard profiles and site-enabling conditions to typology selection and considers supporting blue–green measures within the broader adaptation context. It is applied to three flood-prone settings in northern Poland representing a coastal delta, a river confluence and a lower-river terrace. The methodology combines GIS-based hazard mapping; one-dimensional unsteady-flow HEC-RAS simulations for 50-, 100- and 500-year design events; and parametric structural modelling in Rhino–Grasshopper. Performance is assessed using maximum inundation depth, surface-water retention time, and a probabilistic building damage index. Amphibious dwellings reduce modelled 100-year flood damage by 62% relative to slab-on-grade construction, while modular floating platforms maintain habitability under water-level rises exceeding 5.0 m. In addition, bioretention and blue–green corridors reduce retention time by 18–31%. The results provide a planning-oriented decision logic for expanding adaptive housing options in flood-prone lowland settings under increasing hydrological variability. Full article

The shift from the central place paradigm to the network paradigm in regional relation research emphasizes the need to elucidate the factors and mechanisms driving urban network dynamics. Leveraging firm-level big data—including a headquarters–branch relationships database (29,359 headquarters and 114,679 branches) and an investment relationships database (21,843 investing firms and 69,733 recipients)—this study constructs an urban network integrating both vertical and horizontal enterprise connections. Using exponential random graph models (ERGMs), it analyzes the influencing factors and driving mechanisms of urban network dynamics in the Yellow River Basin (YRB). This study found that the urban network in the YRB is characterized by multiple isolated “core–periphery” radial networks. Strong connections are concentrated within each province’s major cities and their immediate surroundings, while horizontal connections across provincial borders are weaker. From 2000 to 2020, the urban network has evolved from isolated “core–periphery” radial networks to corridor networks where some core nodes are interconnected. The urban network dynamics in the YRB result from the combined influences of the preferential attachment mechanism, the network self-organization mechanism, the multi-dimensional proximity mechanisms, and the geographical boundary effect. Enterprises tend to establish branches or investments in cities with spatial proximity and larger economic scales. Reciprocal and transitive structures significantly facilitate urban network formation. Additionally, institutional proximity, geographical proximity, cultural proximity, cognitive proximity, and geomorphological division all exert varying degrees of influence on enterprise connections between cities. Full article

Railways constitute a core component of China’s national comprehensive transportation network, and their spatial organization and temporal accessibility jointly shape transport integration and system efficiency. Identifying their evolution from the dual perspectives of spatial expansion and time compression is therefore of both theoretical and practical significance. Drawing on fractal theory, this study examines the structural characteristics, evolutionary trends, and driving factors of railway networks in China’s five major urban systems from 2014 to 2024 from a “space–time” dual perspective. The results show that railway networks exhibit a staged pattern of “spatial filling preceding temporal correlation”, with a lag of approximately 1–8 years—about 1 year in the Guangdong–Hong Kong–Macao Greater Bay Area (GBA), 5 years in the Middle Yangtze River (MYR) region and Beijing–Tianjin–Hebei (BTH), and up to 8 years in the Chengdu–Chongqing (CC) region. In addition, clear regional differences are observed: the Yangtze River Delta (YRD) is polycentric, with the greatest potential, projected to continue rapid spatial growth until 2027 and to remain in a fast-growth phase of temporal correlation; GBA is highly coordinated; BTH is developed but characterized by dual-core agglomeration; CC grows rapidly with lagging functionality; and MYR is corridor-dependent with limited potential. These findings indicate that network functionality does not emerge synchronously with infrastructure expansion, but depends on subsequent improvements in operational organization and service capacity. Compared with single-scale-based indicators, the “spatial distribution–temporal correlation” framework more effectively captures network performance and provides quantitative support for transport optimization and coordinated regional development. Full article

Urban districts along major rivers are undergoing rapid transformation, yet long-term evidence on how redevelopment reshapes land cover and vegetation structure remains limited in post-socialist cities. This study examines the spatio-temporal evolution of land use and land cover (LULC) and vegetation dynamics along the Sava River corridor in Belgrade from 1990 to 2024. CORINE Land Cover (CLC) datasets were combined with Landsat-derived NDVI and MSAVI time series, while high-resolution Esri Wayback imagery was used for visual interpretation and qualitative corroboration of the detected land-cover and vegetation patterns. Beyond conventional NDVI/LULC assessments, the study integrates multi-decadal spectral trends with functional vegetation structure classification to evaluate canopy continuity and ecological configuration under contrasting redevelopment models. Results reveal a pronounced divergence between the two riverbanks. The left bank (New Belgrade) maintains stable land-cover composition and consistently higher NDVI and MSAVI values, indicating preserved green infrastructure and sustained canopy continuity. In contrast, the right bank (Belgrade Waterfront) experienced substantial land-cover conversion after 2006, with a statistically significant decline in vegetation greenness (NDVI −0.020 dec⁻¹, p < 0.001) and a marked increase in impervious surfaces. MSAVI-based functional classes indicate a shift from mixed low vegetation to predominantly sealed land, while tree canopy remained persistently low throughout redevelopment. The findings demonstrate measurable ecological simplification and canopy loss, even where nominal green areas remain present. By providing a rare multi-decadal, spatially explicit comparison of two contrasting planning paradigms within the same river corridor, the study contributes new empirical evidence on how governance and redevelopment models shape riparian ecological trajectories and sustainable urbanism in post-socialist cities. Strengthening blue-green infrastructure and restoring native riparian vegetation are essential for enhancing climate resilience and ensuring long-term riverfront sustainability. Full article

The northeastern margin of the Qinghai–Tibet Plateau is an ecologically fragile region that faces severe habitat fragmentation, which directly threatens regional biodiversity conservation and ecological security. To address this challenge, this study constructed a hierarchical “source-corridor-node” ecological network for the Gannan Tibetan Autonomous Prefecture by integrating Morphological Spatial Pattern Analysis (MSPA), the Minimum Cumulative Resistance (MCR) model, landscape connectivity assessment, and gravity modeling. The key results are as follows: (1) The Gannan Yellow River Water Source Replenishment Area contains 11 core ecological source regions, which are predominantly located in the southeastern regions of Diebu County and Zhouqu County, covering a total area of 4237.81 km²; (2) Ecological resistance analysis identifies high-resistance zones concentrated in anthropogenically active river valleys and urban belts (e.g., Hezuo urban area, Awanzang Town, and the G213 corridor). Low-resistance zones are predominantly situated in protected ecological enclaves (e.g., Zhagana Geopark and Gahai Wetland Reserve); (3) A total of 55 ecological corridors were identified, with a total length of 4355.77 km. Among these, 26 were classified as key ecological corridors, primarily distributed in Diebu and Zhouqu counties in the eastern part of Gannan Prefecture. These areas feature relatively concentrated ecological sources, and the key corridors play a critical role in connecting isolated ecological patches and maintaining regional ecological connectivity. (4) Across the entire territory of Gannan Prefecture, a total of 81 first-level ecological nodes and 53 second-level ecological nodes were delineated. As the core hub of the regional ecological network in Gannan Prefecture, Diebu County encompasses 60 First-level and 41 Second-level ecological nodes, respectively. The hierarchical “source-corridor-node” ecological network constructed in this study effectively enhances the overall landscape connectivity of the area. This progressive analytical framework—integrating source identification, corridor extraction, and node diagnosis—provides a scientific basis for biodiversity conservation, territorial ecological restoration, and sustainable development in high-altitude ecologically fragile zones. Full article

Coastal socio-ecological systems are increasingly exposed to the combined pressures of climate change, land-use intensification, hydrological alterations and expanding infrastructure networks. These pressures interact across the land–catchment–lagoon–sea continuum, generating complex feedbacks that challenge traditional planning instruments, which remain sectoral and fragmented. The Mar Menor (SE Spain), a semi-enclosed Mediterranean lagoon affected by intensive agriculture, urbanisation, hydrological modifications and recurrent extreme climatic events, exemplifies this systemic vulnerability. Existing planning frameworks—local urban plans, regional territorial plans, river basin management plans, maritime spatial plans and lagoon-specific strategies—operate independently, each addressing only a fragment of the system and none integrating climate change as a structuring axis. This article introduces Integrated Spatial Planning (ISP) as a novel territorial–climatic framework designed to overcome these limitations. ISP integrates climate forcing, land uses, catchment processes, lagoon dynamics, marine conditions, critical infrastructures, intermodal and energy corridors and multilevel governance into a single analytical structure. A central component of the methodology is a four-zone multilevel zoning system that connects municipal, regional, basin, marine and EEZ planning domains within a unified territorial–climatic logic. The ISP matrix is applied to the Mar Menor to produce the first holistic diagnosis of the system. Results reveal strong land–sea–catchment interactions, high climatic exposure, vulnerable infrastructures and structural governance fragmentation. The matrix exposes systemic incompatibilities and vulnerabilities that remain invisible in sectoral planning instruments. The discussion demonstrates how ISP clarifies the roles and responsibilities of each governance level, supports multilevel coherence and integrates critical infrastructures and intermodal corridors into climate-resilient planning. ISP reframes climate change as the organising principle of territorial planning and provides a replicable, scalable methodology for coastal socio-ecological systems facing accelerating climate pressures. The Mar Menor case illustrates the urgent need for integrated territorial–climatic governance and positions ISP as a scientifically robust and operationally viable pathway for long-term adaptation and resilience. Full article