Earth

This study investigates temporal and spatial variation in torrential flood hazards and sediment dynamics in two ungauged watersheds in southeastern Serbia from 1991 to 2023. By integrating classical hydrological models with modern geospatial and photogrammetric techniques, watershed responses to environmental and anthropogenic changes are quantified. Torrential flood potential was estimated and peak discharges were calculated using both the rational and SCS-Unit hydrograph methods, while sediment transport was assessed through Gavrilović’s erosion potential model and a modified Poljakov model. A key innovation is the use of UAV-based and close-range photogrammetry for 3D grain-size analysis, marking the first such application in Serbia. The mean torrential flood potential decreased by 4.4% in the Petrova Watershed and 4.2% in the Rasnička Watershed. Specific peak discharges for a 100-year return period declined from 1.62 to 1.07 m³·s⁻¹·km⁻² in Petrova and from 1.60 to 1.34 m³·s⁻¹·km⁻² in Rasnička. Sediment transport during a 1% probability flood was reduced from 4.97 to 2.53 m³·s⁻¹ in Petrova and from 13.87 to 9.48 m³·s⁻¹ in Rasnička. Grain-size analyses revealed immobile coarse bedload in the Petrova and active sediment transport in the Rasnička River, where D50 and D90 decreased between 2023 and 2024. The findings highlight the effectiveness of a synergistic methodological approach for analyzing complex watershed processes in data-scarce regions. The study provides a replicable model for flood hazard assessment and erosion control planning in similar mountainous environments undergoing socio-environmental transitions.

The growing pressure on global cropland resources has become increasingly evident. Reconciling the urgency of cropland protection with long-term food demand is crucial for achieving resilient and sustainable cropland management. Here, we develop a comprehensive agricultural dataset and a five-dimensional evaluation framework encompassing quantity, quality, structure, ecology, and sustainability. Through synergy–trade-off analysis and structural equation modeling, we elucidate the interrelationships among these dimensions and their external drivers. By projecting future cropland retention under the Shared Socioeconomic Pathways (SSPs) and integrating multi-dimensional urgency, we propose a spatially explicit framework for resilient cropland management. The results show that (1) cropland protection urgency in the Chengdu–Chongqing Economic Circle exhibits a clear spatial gradient—low in the core areas and high along the periphery, where high-urgency zones are typically characterized by fragmentation, lower quality, and weaker ecological functions. (2) Eleven biophysical and socioeconomic factors collectively explain 23–50% of the variance in cropland protection urgency, with terrain conditions and urbanization levels exerting the strongest influence on cropland quantity, structure, and sustainability. (3) Under the SSPs, the maximum cropland retention reaches 6.944 million ha, with a future fallow ratio not exceeding 6.05%, and 45.05% of cropland designated as reserve resources. (4) Cropland within core protection zones demonstrates multi-dimensional advantages but accounts for less than 5%, highlighting the need for targeted conservation strategies. By integrating cropland protection urgency with long-term food security constraints, this study proposes a multi-level, multizonal resilience management strategy that offers practical guidance for cropland-stressed regions undergoing rapid urbanization worldwide.

This study investigates the morphodynamic evolution of an embayed cobble beach located on a mesotidal cliff coast in northern Spain. La Maruca/Pinquel beach was selected for its distinctive geomorphological setting, perched on a well-sorted cobble substrate and bordered by a slightly elevated (less than 1 m) wave-cut platform. Firstly, the availability of orthophotos and the achievement of field surveys enabled a detailed topographic mapping of morphological features. Sedimentological analyses based on grain size and clast shape revealed characteristics indicative of prolonged low-energy wave conditions. A permanent sharply crested ridge and ephemeral staggered tidal berms define the morphology of the beach. Additional depositional features such as washovers, tabular structures, and lobes are also well developed. Sediment accumulation is most pronounced in the western sector, where overwash lobes migrate landward. A W-to-E gradient in cobble size and the presence of boulders in the lower foreshore can be observed. Secondly, a morphosedimentary model was developed based on the obtained data to interpret the beach’s dynamic behavior under current and projected coastal forcing. Finally, by analyzing orthophotographs spanning a 40-year period (1984–2024), the long-term geomorphological evolution of the beach was documented. The results reveal significant morphological transformations, notably a shoreline retreat of approximately 12 m and a reduction in the cobble-covered surface area, among other findings. Future analyses of sediment transport processes and lithological responses to erosion will be able to offer a deeper understanding of the complex behavior and resilience of pebble beach systems in response to changing environmental conditions.