Search Results (226)

Posidonia oceanica (Delile) is a Mediterranean seagrass species whose fallen leaves accumulate along shorelines, forming compact structures known as banquettes. Despite their ecological and protective functions, these deposits remain insufficiently documented across the Mediterranean and are frequently removed before the summer season due to tourism and aesthetic considerations. This study develops and tests a Geographic Information System (GIS)-based methodology for mapping and inventorying P. oceanica beach-casts across five representative pilot areas along the Italian coastline (Western Sardinia; Liguria; Northwestern Sicily; Elba and Giglio Islands, Tuscany; Gargano coast, Apulia). The approach integrates historical Google Earth imagery with spatial datasets to characterize beach-cast occurrence and persistence and to describe their distribution in relation to selected geomorphological, environmental, and anthropogenic variables. Based on historical Google Earth imagery covering approximately three decades (~1998–present), beach-casts were identified at least once on 94% of the 393 surveyed beaches, indicating that the phenomenon is widespread across the investigated areas, with permanent banquettes representing a substantial component (63%). The spatial distribution of beach-casts was also examined in relation to shoreline dynamics, beach surface type, coastal vulnerability, and beach use, providing a descriptive characterization of their environmental and anthropogenic context, while the relative influence of the considered factors requires further investigation. The resulting standardized and reproducible framework provides a basis for future monitoring and susceptibility assessments across broader coastal sectors and can support evidence-based management of P. oceanica beach-casts. Full article

Artisanal fisheries are fundamental to riverine socioecological systems, yet fishing communities remain underrepresented in environmental governance and decision-making. This gap constrains the incorporation of local knowledge into environmental decision-making and may reduce the effectiveness of governance strategies for addressing complex socioecological challenges. This study analyzes the socio-environmental characteristics of artisanal fisheries in the lower Magdalena River estuarine zone (Colombia) and discusses their implications for water governance and monitoring systems. Using a mixed-methods integrative design, we combined a PRISMA-guided literature review with a structured survey of 43 community members in the strategic territory of Bocas de Cenizas–Ciénaga de Mallorquín. The results reveal strong livelihood dependence on aquatic ecosystems, increasing environmental pressures, and limited institutional coordination. Respondents reported clear perceptions of environmental degradation, including declines in fish availability, vegetation cover, and water quality. Crucially, local actors possess detailed experiential knowledge of these transformations and show favorable conditions for participatory engagement. The integrative analysis indicates that artisanal fishers are not merely vulnerable populations, but key environmental observers whose knowledge can enhance adaptive and inclusive water governance. The findings identify a specific monitoring gap in the lower Magdalena estuarine zone: the environmental changes most consistently perceived by local actors—including declining fish availability, deteriorating water conditions, vegetation loss, and shoreline erosion—are directly linked to livelihood dependence but remain weakly connected to formal governance processes. These locally observed variables provide a context-specific basis for developing integrated socioecological and hydroenvironmental monitoring systems that combine conventional scientific indicators with community-based observations, thereby improving the territorial relevance of environmental information for water governance and decision-making. Full article

Shoreline determination is fundamental to coastal research, spatial planning, and legal boundary delineation but remains challenging in low-relief coastal areas where small sea-level variations can produce substantial horizontal shoreline displacements. This study compares shoreline determination methods based on tide gauge (TG) observations, LiDAR data, Sentinel-1 synthetic aperture radar (SAR) and Sentinel-2 optical satellite imagery using the low-relief coast of Pärnu Bay, Estonia, as a case study. The comparison was based on shorelines derived from Sentinel-1 and Sentinel-2 imagery acquired on selected common acquisition dates within the 2015–2025 study period, rather than on a temporally continuous annual dataset, and compared with temporally matched LiDAR-derived shorelines extracted from a Digital Terrain Model (DTM) generated from a 2021 LiDAR survey. The LiDAR-derived shorelines were extracted using the mean sea level (MSL) observed at the Pärnu and Häädemeeste TGs at the satellite overpass time, while the satellite-derived shorelines were additionally validated against RTK GNSS measurements. The results demonstrate that the evaluated methods produce substantially different shoreline positions. Sentinel-2-derived shorelines generally corresponded more closely to the temporally matched LiDAR-derived shorelines than Sentinel-1-derived shorelines and most accurately represented the instantaneous land–water boundary during field validation. These findings demonstrate that different shoreline determination methods represent different shoreline definitions. Consequently, shoreline datasets should be interpreted according to their intended purpose rather than treated as directly interchangeable. Full article

Environmental monitoring of freshwater ecosystems faces significant challenges in detecting illicit wastewater discharges, which often remain unrecognized due to their intermittent nature and limited spatial footprint. This study presents a novel integrated strategy combining satellite remote sensing, Unmanned Aerial Vehicle (UAV)-based proximal sensing, and in situ measurements to enhance pollution detection in vulnerable aquatic environments. The methodology was applied to Lake Avernus (Italy), a volcanic lake historically affected by eutrophication and toxic cyanobacterial blooms. Landsat 8–9 thermal analysis revealed no detectable anomalies, reflecting the limitations of its coarse spatial resolution. Sentinel-2 multispectral imagery was then analyzed through spectral indices, band ratios, and reflectance signatures, revealing localized variations in surface reflectance and spatial heterogeneity in water optical properties. These satellite-derived anomalies guided targeted high-resolution UAV surveys. UAV-based thermal imaging revealed an elevated-temperature zone along the adjacent shoreline. In situ field screening flagged a candidate chemical anomaly at this location. The hierarchical framework demonstrates that satellite screening effectively identifies areas of concern, while UAV thermal imaging enables high-resolution localization of features invisible to satellite sensors, and in situ measurements provide essential ground-truth validation. This replicable, low-cost methodology offers a powerful tool for early warning, surveillance, and sustainable management of sensitive freshwater ecosystems. Full article

Coastal litter accumulates along urban shorelines, yet the floating and stranded litter compartments of tourism-intensive coastal cities are rarely characterised side by side. We conducted monthly macro-litter surveys over one year (April 2023–March 2024) at two Dubrovnik sites less than 200 m apart, each representing a different litter compartment: Porat harbour, a semi-enclosed basin retaining floating litter, and Posat, an urban beach collecting stranded debris. Surveys followed the updated European MSFD marine litter monitoring guidance. In total, 1325 items were recorded at Porat and 1768 at Posat. The harbour was far more variable month to month (coefficient of variation 135% versus 77%), consistent with episodic basin retention. Artificial polymers dominated both compartments (84.9% at Porat; 79.2% at Posat), but the leading category differed: plastic fragments in the harbour and expanded polystyrene on the beach. Composition differed significantly between the two compartments (PERMANOVA, p = 0.038), though the separation was modest. Because each compartment requires a different sampling method, compartment and sampling method are fully confounded; absolute magnitudes are therefore reported separately and not compared. At Posat, where cleaning was suspended, the Clean Coast Index averaged 7.1 (moderate) but ranged from 1.5 to 21.9 between months, spanning all five cleanliness classes. These distinct signatures indicate that single-compartment monitoring may overlook urban coastal heterogeneity, and that mitigation requires compartment-specific measures. Full article

Living shorelines are widely promoted as nature-based solutions to coastal erosion and wetland protection, yet hardened shoreline structures continue to dominate even in jurisdictions with explicit policy mandates prioritizing living shorelines. In this research, we examine why non-optimal shoreline modification outcomes persist in Virginia (USA) despite a regulatory framework designed to promote ecological alternatives. We use primary data from interviews with wetlands board members, marine contractors, and nonprofit organizations and findings from a secondary survey of shoreline property owners to analyze shoreline management as a multi-sector collaborative decision-making process. Findings show that shoreline outcomes are shaped less by individual regulatory decisions than by recurrent interaction mechanisms across sectors that operate upstream of permit review. Contractors play a critical agenda-setting role by shaping the alternatives presented to property owners, while social norms, anticipatory adaptation to regulatory expectations, and informal decision heuristics constrain option sets before projects reach wetlands boards. Formal co-management institutions are therefore asked to arbitrate projects that are already highly constrained, limiting their ability to advance policy goals. Improving policy fidelity requires attention to decision sequencing, intermediary incentives, and structural feedback dynamics, rather than simply refining permitting guidance. Targeting upstream decision points and interaction mechanisms offers greater potential to align shoreline management outcomes with living shoreline policy objectives. Full article

The use of Satellite-Derived Bathymetry (SDB) constitutes an efficient, cost-effective, time-saving, and scalable approach for generating high-resolution shallow-water bathymetry. In this context, SDB can be proven to be a valuable method for supporting bathymetric surveys of submerged archaeological sites. This paper focuses on the ancient city of Asopos, located on the coast of the modern village of Plytra in Laconia, SE Peloponnese, Greece. The site occupies an extensive coastal area characterised by numerous ancient remains and geomorphological features distributed along the shoreline and within the nearshore zone. To achieve the objective of producing a very-high-resolution SDB map, one empirical and four machine learning approaches were evaluated: (a) the quadratic Stumpf band-ratio model; (b) Categorical Boosting; (c) Random Forest; (d) Extreme Gradient Boosting, with all models trained using the same three optimal spectral band ratios; and (e) the CatBoost model trained using principal components derived from a Principal Component Analysis of the multispectral dataset. These approaches were developed using multispectral WorldView-2 imagery and 208 in situ depth measurements as ground truth, collected across a different range of depths and distances from the coastline. Pan-sharpened imagery was used for visual interpretation. Model accuracy was assessed using an additional validation dataset of 57 depth measurements. This combined approach demonstrates that VHR SDB mapping of the nearshore zone is highly effective when employing three band ratios involving the blue, green, and yellow bands, achieving a root mean squared error of less than 1 m, and can therefore serve as a reliable method for shallow-water geoarchaeological investigations. Full article

Digital twins are increasingly adopted in geographic research as dynamic representations of environmental systems; however, their application to regulated river shorelines remains limited, particularly where bathymetric change, hydrological variability, and shoreline-state dynamics must be integrated within a single GIS-based framework. This study develops and validates a GIS-based spatiotemporal digital twin-oriented framework for the dam-affected shoreline downstream of the Włocławek Dam, Poland. The framework integrates four bathymetric surveys acquired in 2008–2011, water-level records, airborne laser scanning data, and three-dimensional hydrotechnical infrastructure within a unified geodatabase designed for dynamic shoreline-state reconstruction, multi-epoch analysis, and environmental monitoring. A key methodological element is the treatment of water level as a dynamic reference surface, enabling the automated delineation of inundation and exposure zones for observed and scenario-based hydrological conditions. The reconstructed bathymetric surfaces were organized as a multidimensional raster dataset with time as an explicit analytical dimension, supporting repeatable change detection, cross-sectional interpretation, and temporal trend analysis. To extend the framework beyond purely retrospective analysis, a near-real-time hydrological updating component was implemented through ingestion of operational water-level observations from the IMGW API into the geodatabase. Validation of the trend-based prediction for 2011 yielded R² = 0.967, RMSE = 0.44 m, MAE = 0.28 m, and bias = −0.06 m. The proposed framework provides a transferable geospatial basis for spatiotemporal modelling and monitoring of regulated river shoreline dynamics under changing hydrological conditions. Full article

Barrier islands along Florida’s Atlantic coast are increasingly threatened by sea-level rise, intensified hurricanes, shoreline armoring, and rapid coastal development. This study examined how beach and dune configurations varied in relation to coastal elevation patterns, NDVI-based surface greenness, and stakeholder perceptions across the East Central Florida Atlantic coast. Light Detection and Ranging (LiDAR) elevation datasets (2016, 2022, 2024), National Agriculture Imagery Program (NAIP)-derived Normalized Difference Vegetation Index (NDVI) analyses (2015, 2019, 2023), and stakeholder survey data from two coastal resilience workshops conducted in Volusia County in November 2024 were assessed to evaluate geomorphic change, vegetation-greenness patterns, and public perceptions of shoreline management strategies. Results showed descriptive differences among shoreline-type groups. Seawall-backed sites experienced the greatest net elevation loss (−0.529 m averaged over two sites) and a small negative mean transect-level NDVI change (−0.034) between 2015 and 2023, while natural dune sites showed an overall elevation gain (0.255 m averaged over three sites), despite some site-level loss after the 2022 hurricanes, and no net mean transect-level NDVI change (0.000) over the same NDVI period. Because the LiDAR and NDVI datasets are not temporally matched, these patterns are interpreted as complementary rather than causal lines of evidence. Stakeholder survey responses demonstrated that most respondents recognized the importance of dunes and coastal vegetation for resilience, but also expressed concerns about effectiveness, long-term maintenance, and cost of natural or hybrid solutions. Overall, the findings suggest that natural and minimally armored shorelines may retain greater capacity for elevation and vegetation-greenness recovery than hardened coastal systems, while also emphasizing the need for adaptive, conservation-based coastal management strategies that account for both physical shoreline conditions and stakeholder concerns. Full article

Colombia hosts 28 species of freshwater and terrestrial turtles, yet anthropogenic pressures such as illegal trafficking and urban expansion have intensified risks. In Cali, non-native turtles are frequently introduced into wetlands through pet abandonment and confiscations, creating novel assemblages in urban ecosystems. To examine this issue, ecological surveys were conducted in three urban wetlands during December 2024, complemented by enforcement records from the Wildlife Rescue Center (WRC) spanning 2015–2023 and reports from environmental authorities. Turtles were captured manually using natural baits placed in floating containers or along shoreline areas to attract individuals, then identified morphologically, measured for standard morphometric parameters, and released at the site of capture. WRC records were reviewed to assess species composition and causes of admission. Field sampling yielded 109 individuals representing four species (Trachemys callirostris, Podocnemis unifilis, Kinosternon leucostomum, Rhinoclemmys melanosterna). WRC records documented 2751 individuals across 11 species, with five taxa accounting for over 96% of admissions. Both datasets revealed a predominance of Trachemys callirostris. Morphometric data indicated multiple size classes, suggesting demographic heterogeneity within the turtle populations inhabiting the sampled wetlands. The overlap between confiscation records and wetland observations suggests potential links between illegal trade and species presence in urban wetlands, while the predominance of voluntary surrenders reflect the influence of enforcement activity and pet abandonment. Collectively, these findings demonstrate how urban wetlands facilitate the persistence of non-native turtles, reshaping species composition and underscoring the urgency of integrated strategies that combine enforcement, habitat management, veterinary protocols, and citizen education to safeguard native biodiversity. Full article

The intertidal beach profile provides a fundamental representation of beach morphology and serves as a key indicator of shoreline morphodynamics. To enable frequent and accurate mapping of intertidal beach profiles, this study proposes an automated reconstruction framework that integrates single-pixel image columns with a stacked bidirectional long short-term memory (Bi-LSTM) network. Time-exposure imagery, commonly referred to as Timex imagery, acquired from a shore-based video monitoring station at Xisha Bay, China, is used as the primary data source, while wave records obtained from a wave buoy are incorporated to assign elevations to the detected waterline breakpoints, thereby enabling automatic beach profile reconstruction. The stacked Bi-LSTM network is trained for land–sea segmentation and waterline breakpoint localization. achieving the best performance among the tested methods, with precision, recall, accuracy, and F1 score values of 0.951, 0.894, 0.978, and 0.903, respectively, and a mean breakpoint localization error of 2.23 pixels. Breakpoint elevations were then estimated using a local slope–wave setup attribution model. Validation against field-measured topographic data from four fixed profiles and three survey periods showed good agreement between the reconstructed and measured profiles, with a period-based root mean square error (RMSE) of 0.212 ± 0.080 m. When all validation points were combined, the reconstructed elevations showed strong agreement with the measured elevations, with a coefficient of determination (R²) of 0.988 and an overall RMSE of 0.24 m. The profile comparisons further showed that the reconstructed profiles generally captured the overall profile shape and cross-shore morphological pattern of the measured profiles, although reconstruction accuracy varied among the four fixed profiles. These differences demonstrate that camera viewing angle, field-of-view position, camera-to-profile distance, and image quality are important factors influencing video-derived beach profile reconstruction. These results indicate that the proposed method can directly reconstruct fixed intertidal beach profiles from shore-based Timex imagery without generating a digital elevation model of the entire intertidal zone. It provides a practical tool for high-frequency monitoring of intertidal profile morphology and supports the quantitative analysis of beach erosion–accretion dynamics. Full article

Oil Detection Canines (ODCs) have been proven to detect spilled oil in various environments, including targets and residual oil sequestered along shorelines. A limitation within the capability is that an ODC detects and responds to all types of stranded hydrocarbons, including any from historical spills or naturally occurring chronic oils, such as tarballs washed up from offshore seeps. In locations historically known for chronic tar deposits, the value of a K9-supported Shoreline Cleanup Assessment Technique (SCAT) survey is limited when large numbers of tar deposits are present, because the canine detects and responds to all of them. This thoroughness can slow down SCAT surveys, reduce efficiency by requiring investigation of each response, and fatigue the canines from the number of alerts. A project supported by the Texas General Land Office (TGLO) was designed to investigate the ability of a trained ODC to discriminate hydrocarbons on a beach that represent a newly spilled oil while ignoring other potential “background” oils. In 2021, Texas Tech University’s Canine Olfaction Lab conducted a laboratory-based study to investigate canines’ ability to respond to weathered oil samples. This research demonstrated that trained canines could effectively discriminate between weathered oils in a laboratory environment. This knowledge was used to design a field program to conduct monthly surveys with two teams: one involved deploying two canines trained on a sample representative of relatively unweathered spilled oils, handled by citizen-scientist volunteers, and the other involved an ODC trained on a range of oil types. The field survey results show that a Specific Oil Detection Canine (SODC) can discriminate between unweathered oil deposits and other background deposits typical of chronic oiling at the same location. Field surveys indicated that SODCs consistently responded exclusively to target oil samples and disregarded naturally occurring background hydrocarbons, while a generalist ODC responded to all hydrocarbon sources present. Full article

Bangladesh is an extremely climate-exposed country, with erosion, accretion, tidal surges, and cyclones continuously modifying coastal districts. Shoreline change in Bangladesh is crucial for sustainable coastal management and disaster resilience. Therefore, the objectives of this research are as follows: (i) to assess accretion- and erosion-based shoreline changes of the Bangladesh delta adjacent to the Bay of Bengal for 2021–2025 using a fixed 2021 reference shoreline and a 2025 shoreline proxy extracted from Landsat 8/9 imagery, and (ii) to explore onshore change dynamics from satellite-derived NDVI, NDBI, and NDWI for 2022–2025. The study covers 14 coastal districts and integrates the 2021 baseline shoreline, Survey of Bangladesh geospatial datasets, and 17,055 Ground Reference Points (GRPs) to support geometric consistency and spatially explicit reporting at the delta scale. Three spectral indices—Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), and Normalized Difference Built-up Index (NDBI)—were applied to assess vegetation health, surface water distribution, and built-up/exposed land characteristics. Results indicate spatial variability in coastal change, with 383.49 km² of land gained through accretion and 124.12 km² lost to erosion, resulting in a neat accretion of 259.37 km² between 2021 and 2025; 8747.91 km² remained geomorphologically stable. Spectral index trends show minimal inter-annual NDVI and NDWI variability, suggesting stable vegetation cover and no long-term expansion of surface water. In contrast, a slight increase in NDBI indicates localized exposure of new sediments or small-scale land-use transitions along emerging coastal zones. Spearman correlation analysis highlights consistent negative relationships between NDVI and NDWI and moderate contrasts between NDVI and NDBI, reinforcing the coexistence of vegetation recovery, water withdrawal, and sediment-driven land emergence. The novelty of this study lies in the provision of consistent, near-real-time coastal change inventory for the full ~710 km Bangladesh delta coastline by combining a common 2021 baseline shoreline with harmonized Landsat 8/9 OLI surface reflectance (2022–2025) and linked onshore spectral-index dynamics over the same period. Overall, this short-term assessment reveals a sedimentary system that is active but balanced, with accretion surpassing erosion despite cyclone-affected disturbances, underscoring the value of operational satellite monitoring for coastal management, hazard preparedness, and climate-adaptive planning. Full article

This study assesses the comparative performance of two geotechnologies for shoreline monitoring—Unmanned Aerial Vehicle (UAV) surveys and CoastSnap citizen-science imagery—at Guarita Beach, southern Brazil. The analysis was based on twelve paired monitoring dates distributed over a two-year interval. Shorelines were extracted from the wet–dry line, manually digitized from UAV orthomosaics, and automatically detected from CoastSnap images with subsequent quality control. Shoreline change was quantified in the Digital Shoreline Analysis System (DSAS) using the Shoreline Change Envelope (SCE) and the Linear Regression Rate (LRR). The SCE showed the highest equivalence between methods, with a mean difference close to zero (−0.14 m) and no evidence of systematic bias. For LRR, values derived from CoastSnap tended to be lower than those derived from UAVs (mean difference = −2.14 m year⁻¹), although without statistically significant divergence at the adopted significance level. The results demonstrate that the agreement between CoastSnap and UAV data depends directly on the metric analyzed: SCE was more robust for inter-method comparison, whereas LRR was useful for medium-term trend interpretation but more sensitive to uncertainty propagation. Overall, CoastSnap did not replace UAV surveys, but it proved to be a valuable complementary tool for expanding temporal coverage in coastal monitoring programs. Full article

In recent decades, the issue of marine litter has emerged as a major environmental concern, particularly with regard to plastic litter. The European Marine Strategy Framework Directive (MSFD, 2008/56/EC) requires member states to monitor marine litter along the coast, in the water, and on the seabed. Since 2014, beach litter monitoring has been carried out in Italy’s coastal regions, an activity entrusted to the Regional Environmental Agencies System (ARPA). ARPA Puglia is responsible for monitoring the Apulian coastline, and this paper summarizes the main results obtained from 2014 to 2023. The monitoring, which was repeated twice a year, consists of a visual census of litter items along a 100-meter stretch of beach in six different locations across the Puglia region. During this period, an average of 506 litter items per 100 m were observed on the six target beaches in Puglia, 90% of which were plastic ones. Among these, single-use plastic items (SUPs) accounted for 37%. A trend analysis reveals a decline in the aggregate quantity of marine litter on Apulian beaches over the past decade, a phenomenon that is particularly evident when considering the SUP subcategory in isolation. This decreasing trend is consistent with the overall pattern observed along the Italian coastline and the coastlines of European seas. Consequently, it can be hypothesized that an increase in awareness of the issue, in conjunction with the implementation of European Directive 2019/904 for the reduction in single-use plastics, has resulted in more responsible practices. However, further efforts are needed to achieve the goal of 20 litter items per 100 m of beach to attain the Good Environmental Status under the Marine Strategy Framework Directive. The findings emphasize the importance of constant monitoring of litter items along the shoreline, as well as the integration of new and alternative methodologies (e.g., drone surveys) to evaluate the efficacy of European regulatory implementation. Full article