Small urban mangrove remnants may undergo substantial spatial reorganization that regional land-cover products or endpoint area change alone poorly represent. Arboreal canopy dynamics were reconstructed in an urban estuarine sector within a common 12.75 ha cartographic region of interest (ROI) of the Estero Salado in Guayaquil, Ecuador, using twelve historical images with visually interpretable canopy boundaries accessed through Google Earth Pro v7.3.6 between 2003 and 2023. The mapped class represents a visible woody canopy rather than validated species-specific mangrove cover and may therefore include non-mangrove woody vegetation along terrestrial margins. Canopy polygons were quality-controlled and analyzed for area change, patch configuration, endpoint overlap, gain and loss, Jaccard similarity, and repeated presence; a December 2025 UAV orthomosaic provided an independent contemporary spatial reference. Mapped canopy area increased from 1.75 to 2.44 ha (+39.7%), but the trajectory was strongly non-monotonic. Between 2003 and 2023, 1.28 ha was mapped at both endpoints; 1.16 ha represented gain, and 0.472 ha represented loss, yielding 1.64 ha of gross mapped spatial turnover. The 2022–2023 interval alone accounted for 76.6% of the total net gain while including 0.303 ha of mapped loss. Patch configuration also changed substantially, and only 0.27 ha (7.6% of the 3.58 ha union footprint) were mapped as canopy at all twelve sampled dates, without implying uninterrupted presence between dates. By integrating canopy-area change with spatial turnover, patch configuration, and repeated canopy presence, this study provides a fine-scale monitoring framework capable of detecting internal spatial reorganization that endpoint area estimates alone may overlook in small urban mangrove remnants.
Aging concrete seawalls are increasingly exposed to deterioration and sea-level-rise (SLR)-related hydraulic demands, yet the fracture response of pre-existing water-accessible cracks under combined coastal loading remains insufficiently understood. A MATLAB R2025a-based coupled BEM-FEM framework is developed to evaluate a plain-concrete gravity seawall using linear-elastic fracture mechanics (LEFM) under plane-strain conditions. Quadratic boundary elements represent the uncracked seawall region, while a locally refined Q8 FEM patch with quarter-point elements represents the toe-crack response. Parametric analyses consider self-weight, 25% and 50% backfill-pressure reductions, seawater levels of 1.52, 1.82, and 3.05 m, crack-face hydrostatic pressure, and normalized crack lengths, a/W = 0.1–0.7. Benchmark and mesh-sensitivity studies demonstrate stable fracture parameters. Results show that a/W primarily governs the nonlinear increase in fracture response, whereas crack-face hydrostatic pressure reduces both the closure tendency and the J-integral-based equivalent stress-intensity magnitude, KJ. Elevated seawater levels and backfill reduction exert secondary influences. The toughness-normalized index remains below unity, and crack-face displacement is normal-component-dominant. Independent ANSYS 2021R1 analyses provide trend-level corroboration of reduced equivalent fracture magnitude and closure-directed displacement. Overall, the coupled BEM-FEM framework identifies crack length and assumed concrete fracture toughness as governing parameters for the screened response and provides an efficient numerical approach for coastal concrete fracture assessment.
The coastal wetland in the Nin Lagoon, Croatia, represents a valuable and ecologically sensitive transitional ecosystem between land and sea. The aim of this study was to determine the presence and distribution of halophytic communities and seagrasses and to create a detailed vegetation habitat distribution map of the study area. Field research was conducted through visual census, photographic documentation, GPS mapping of vegetation, and the use of an unmanned aerial vehicle (DJI Mavic Air 2; SZ DJI Technology Co., Ltd., Shenzhen, China) to generate high-resolution orthophoto imagery. Spatial data were processed in GIS to identify habitat types, calculate polygon areas, and perform descriptive statistical analyses. Three halophytic habitat types were identified: glasswort and saltwort saltmarshes, Mediterranean tall rush communities, and reed and cattail beds. The confirmed seagrass were Cymodocea nodosa and Ruppia sp. The finding of Ruppia sp. is particularly significant, as this species was not previously recorded in the national map of coastal and benthic marine habitats. The two seagrass species mostly occurred in mixed stands, with some isolated populations. A total of 17.12 ha of saltmarsh area was mapped, including 11.89 ha of halophytic habitats and 5.23 ha of seagrass communities. These results confirm the ecological importance of the studied wetland and provide essential spatial data for future monitoring, conservation, and sustainable management of this sensitive coastal ecosystem.
The morphodynamics of macro-tidal embayed sandy beaches were studied by numerical experiments. The focus was placed on the generation and evolution of morphological features on schematised plane-sloping embayed beaches subjected to both large semi-diurnal tides and energetic wave conditions through a spring–neap tidal cycle. We relied on the advanced process-based XBeach model to simulate coupled hydrodynamics, sediment transport and morphological changes. Two differently sized rectangular beaches were considered. The model predicted on both beaches an extensive longshore morphological system made of a subtidal bar and an intertidal runnel. Both features were found to be controlled by the ratio of wave height to tidal range and spring–neap tidal variation. Boundary effects were revealed by the occurrence of small transverse sand deposits along headlands and the accretion and curvation of the longshore bar ends. The impact of bordering headland features on predicted morphodynamic evolutions appeared mainly associated with overall and specific embayment characteristics. Topographic headland rips were revealed to be of primary importance in regulating these morphodynamics. A suite of involved processes and underlying mechanisms was furthermore proposed. The wave obliquity was thus found to asymmetrise the entire bar–runnel system in both alongshore and cross-shore directions. The level of asymmetrisation appeared positively correlated to the level of embaymentisation.
Sea-level rise may substantially reduce the dry space available on sandy beaches, although its effects depend strongly on local beach characteristics. This study evaluates the residual spatial functionality of five beaches in southern Spain using two normalized indicators: residual available surface area (FA) and residual available beach width (FW). Both express the proportion of dry beach space remaining relative to a common present-day reference condition without wave run-up. The analysis builds on previously calculated inundation results for present conditions and Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 scenarios for 2026–2045 and 2081–2100, including astronomical tide, meteorological residual, sea-level rise, and wave run-up. Marked differences are observed among the studied beaches across both time periods. Under RCP 4.5 in 2026–2045, Torreguadiaro retains 85.1% of its reference area and 79.8% of its reference mean width. Rinconcillo retains 31.9% and 38.7%, respectively. Under RCP 8.5 in 2081–2100, these values decrease to 75.6% and 65.3% at Torreguadiaro. At Rinconcillo, they decrease to 7.1% and 17.6%. FA and FW also evolve differently among sites: their values remain relatively close at Malagueta but diverge markedly at Rinconcillo under the most severe scenario. Joint consideration of FA and FW therefore provides complementary information on the amount and configuration of residual dry beach space and may support comparison among beaches from a coastal management perspective.
