Search Results (111)

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

Revealing scale effects and the mechanisms underlying the relationships between plant species and functional diversity is crucial for understanding the stability of desert ecosystems and formulating multiscale conservation strategies. In this study, the spatial patterns of plant species and functional diversity in the Gurbantunggut Desert were analysed via multiscale grid sampling. The results indicated that (1) both species diversity and functional diversity indices exhibited high spatial heterogeneity. At the small scale (10 m × 10 m), the values of the Shannon–Wiener and Pielou indices for fixed dunes were higher in the south than in the north. At the medium and large scales (20 m × 20 m and 50 m × 50 m, respectively), the index values were highest in the southwest, with generally greater values in the south than in the north. For semifixed and mobile dunes, the Shannon–Wiener and Pielou index values exhibited an east-high–west-low pattern at the 10 m × 10 m scale. This differentiation decreased with increasing scale, with the highest values observed in the northeast and southwest at the 50 m × 50 m scale. The spatial differentiation in functional diversity indices (Rao’s second-order entropy index and functional evenness index) exhibited distinct characteristics across the different dune types. (2) The spatial variation in all the diversity indices monotonically decreased with increasing scale, with the variance in the species diversity indices indicating the following order: Shannon–Wiener index > Pielou index > Simpson index. (3) The relationships between species richness and diversity indices exhibited significant scale dependence. At the small and medium scales, species richness was significantly positively correlated with the Shannon–Wiener index, Simpson index, and Rao’s quadratic entropy index and significantly negatively correlated with the Pielou evenness index and functional evenness index. However, at the large scale, none of these correlations were significant. (4) The species diversity indices and Rao’s quadratic entropy index were significantly positively correlated at the small and medium scales (p < 0.01), whereas a significant positive correlation with the functional evenness index was observed only at the 10 m × 10 m scale (p < 0.01). At the larger scale, these correlations became insignificant. In fixed dunes, areas of high Simpson index values exhibited a spatially complementary distribution with areas of high Shannon–Wiener index and Pielou index values, providing evidence for the combined effect of local processes such as competitive exclusion and dispersal limitation. Through comprehensive multiscale analysis, this study revealed the mechanisms underlying the scale-dependent relationships between plant species and functional diversity, thereby providing a theoretical basis for protecting and restoring desert biodiversity. Full article

Aeolian sand bodies unrelated either to coastal barrier systems of Holocene or earlier age or to modern beaches have been identified along the central New South Wales coast of southeast Australia. Some of these deposits cap headlands or are located above high sea-cliffs. Others lie below modern sea-levels, whilst one substantial dune field extends 12 km inland. Many of these have previously been interpreted as Early Holocene cliff-top dunes, the product of the migration of beach sands up aeolian sand ramps at the foot of the sea-cliffs of the region and onto the cliff tops. The rising sea-levels of the Middle Holocene eroded the ramps and cut off the supply of sand to the dunes, allowing them to stabilise. But re-investigation shows that these dune fields accumulated at times of low Quaternary sea-levels, with a particle-size distribution suggestive of an inland rather than a coastal origin. We therefore propose an alternative model for the accumulation of these features. At times of low sea-level, sediments exposed on the inner shelf were reworked onto the adjacent coast by onshore winds, where they accumulated in locations unconnected to the modern or the earlier Holocene coastal aeolian sedimentary regime. This model challenges the conventional story that the dominant glacial maximum winds across southeastern Australia were from the west (and thus offshore). This pattern of sediment accumulation and its associated wind regime may have been more stable (continuing for over 30,000 years) and more long-lived (repeated through at least the last two glacial cycles) than has previously been believed. Although the cliff-top dune model has been widely applied, we question its suitability in its type location and suggest a more cautious approach to its application elsewhere. We argue that the products of the landward aeolian reworking of sediment exposed on the continental shelf have been overlooked, despite their potential for the preservation of long-term environmental records. Full article

Eligmodontia dunaris is a small rodent endemic to the Atacama Desert, discovered in the Los Choros dunes (La Higuera, Coquimbo Region, Chile). This study documents new records of the distribution, as well as relevant data on the natural history of this species. Records of geographic distribution were obtained in the field and from published data. The standardized number of captures was calculated by the IDR index. The ability to concentrate urine was evaluated using the RMT renal index. Reproduction and development data were obtained from pregnant females in the field and from animals that mated in the laboratory. Fourteen new locations between the type locality “Los Choros” (Coquimbo Region) and “Diego de Almagro” (Atacama Region) were recorded. In all these localities, captures of E. dunaris were low, except during periods of the flowering desert. In the laboratory, this rodent had two to three consecutive litters in a single breeding season, producing three to five pups per litter. Renal indices measured in five adult specimens (RMT = 7.9 ± 0.8) indicated that E. dunaris can concentrate urine around 4059 ± 120 mOsm/kg. These results may suggest that this species has developed physiological and ecological strategies to colonize the extreme arid environments of northern Chile, allowing it to spread across 11,267 km² in the Atacama Desert. Full article

Oceanfront relief varies along coastlines and serves as the first barrier to wave and surge damage. However, forecasted increases in storm frequency and sea levels are anticipated to enhance coastal erosion, potentially weakening this protection. The land–sea transition is variable along the New England coast, USA, and this variability has produced a range of coastal morphologies that can vary over short distances. It is important to track the beach transition zone to better understand transformations of the system and related hazard risks. A combination of field and computer-based methods was used to evaluate the beach transition zone of southwestern Rhode Island to determine alongshore variability and dynamics. More specifically, a decadal-scale study was conducted to examine changes in morphology from 2011 to 2022, and a short-term study at South Kingstown Town Beach examined changes from November 2023 to January 2024 using time-series drone-derived elevations. Classification of over 500 cross-shore transects illustrated the dominance of sedimentary shorelines, with smaller areas of rocky outcrops and hardening. Analysis of four different years (2011, 2014, 2018, and 2022) determined that beaches with dune morphology were the most common type of transition zone (41–47% of the transects) and transects with a high bank upland were the next most frequent class (34–41%). Following Hurricane Sandy in 2012, a 6% decrease in the number of dune-classified transects was measured; however, one-third of those recovered dune morphology by 2022. The greatest beach transformations over the short-term study occurred in response to strong storms in the 2023–2024 winter season, during which lateral beach movement (erosion) exceeded 15 m in portions of South Kingstown Town Beach. Dune erosion was accompanied by overwash flooding and deposition, and the area remained low-lying and thus vulnerable to future impacts. The beach transition zone classification and insights from this research will be informative for future planning by coastal communities by determining at-risk shorelines based on underlying geology and the stability of morphological features. Full article

Successful escapes depend on many factors, including predator type and habitat characteristics. Examining escape usually entails directly pursuing an individual and then measuring flight initiation distance (FID), but the effect of prolonged pursuit has not been well studied. We examined escape sequences by blanched adult lesser earless lizards (Holbrookia maculata) in the Salt Basin Dunes (SBDs), testing the hypothesis that escape success and sequences would vary with sex and vegetation use. Their coloration is an adaptation to their sparsely vegetated white sand habitat. To evaluate escape behavior, we followed an individual directly until it disappeared (=successful escape), stopped moving, or 2 min elapsed. We recorded trial habitat (at the start and throughout), time to trial end, FID, length of moves, and total distance moved. FID varied with starting habitat—lizards beginning trials on exposed wood had the longest FID. The sexes differed in their move lengths: females made more short moves, while males made more long moves. The most important plant was sage (Artemisia filifolia), which was occupied at the start of 39% of trials, while 71% of trials ended in sage, and larger sage bushes supported longer escape sequences. Our study highlights the importance of vegetation for refuge and emphasizes the crucial role of the dune-plant landscape to lesser earless lizards. Full article

Human recreation is an increasingly popular activity; however, an increase in recreational pressure in wilderness areas can contribute to issues such as human–wildlife conflict, introduction of invasive species, vegetation and soil degradation, riparian area impacts, and anthropogenic waste. While remote camera studies are frequently used to assess the response of wildlife species (i.e., grizzly bears) or ecosites (i.e., coastal sand dunes) to human recreational disturbance, classifying and quantifying human recreational behavior, including differences in spatial, temporal, and recreation types, is less common and presents unique design challenges. Here, we present our practical design considerations and lessons learned from a study quantifying human recreation along trails in the northern Rocky Mountains of Alberta, Canada. We describe our standardized protocol to deploy our camera array, and image classification and analysis of recreation use by type and group size. Finally, we provide practical recommendations for future work attempting to evaluate human recreation in wilderness settings relative to landscape management outcomes. Full article

Functional properties of coastal halophytes are important for development of salt-tolerant cash crop cultures. The study of salt tolerance in coastal dune-building grass Leymus arenarius holds significant importance for its application in land reclamation, soil stabilization, and enhancing crop resilience to salinity stress. We used two accessions (LA1 and LA2) of L. arenarius to compare effects of salinity caused by NaCl and NaNO₃ on growth, ion accumulation and mineral nutrition in controlled conditions. L. arenarius plants exhibited high tolerance to sodium salts, with distinct effects on growth and development observed between chloride and nitrate treatments. While both salts negatively impacted root biomass, nitrate treatment (50–100 mmol L⁻¹) increased leaf number and biomass in LA2 plants, whereas chloride treatment decreased tiller and leaf sheath biomass. Despite individual variations, salinity treatments showed comparable effects on traits like tiller and leaf count, as well as leaf blade and sheath biomass. Salinity increased water content in leaf blades, sheaths, and roots, with LA2 plants showing the most pronounced effects. Chlorophyll a fluorescence measurements indicated a positive impact of NaNO₃ treatment on photosynthesis at intermediate salt concentrations, but a decrease at high salinity, particularly in LA2 plants. The accumulation capacity for Na⁺ in nitrate-treated plants reached 30 and 20 g kg⁻¹ in leaves and roots, respectively. In contrast, the accumulation capacity in chloride-treated plants was significantly lower, approximately 10 g kg⁻¹, in both leaves and roots. Both treatments increased nitrogen, phosphorus, and manganese concentrations in leaves and roots, with varying effects on calcium, magnesium, iron, zinc, and copper concentrations depending on the type of salt and tissue. These findings highlight the potential of L. arenarius for restoring saline and nitrogen-contaminated environments and position it as a valuable model for advancing research on salt tolerance mechanisms to improve cereal crop resilience. Full article

The interaction between freshwater and saline water in coastal wetlands generates an interface zone where vertical and horizontal salinity gradients develop. This interface has been investigated through geophysical, hydrochemical, and isotopic studies, which constitute useful tools that provide different types of information whose combined interpretation allows for a more comprehensive understanding of the processes associated with this interaction. This work assessed, through an integrated geophysical (electrical resistivity tomography), hydrochemical (major ions), and isotopic (δ²H, δ¹⁸O, and ²²²Rn) study, the freshwater–saline water interaction between marsh and dune environments in the Punta Rasa Natural Reserve (Argentina). Results show that salinity gradients occurring between dune and marsh environments are associated with fresh groundwater discharge and rainwater infiltration. Fresh groundwater discharge takes place in topographically elevated dunes, where freshwater lenses form. This discharge generates vertical and horizontal salinity gradients because the hydraulic gradient causes the interface to migrate with the groundwater flow. In low-relief dunes, lenses do not develop and the salinity gradient that develops within the interface due to rainwater infiltration is vertical. The findings clarify plant zonation linked to freshwater–saline water interfaces and provide environmental data to assess wetland resilience to climate-driven changes. Full article

Coastal profile models are frequently used for the computation of storm-induced erosion at (nourished) beaches. Attention is focused on new developments and new validation exercises for the detailed process-based CROSMOR-model for the computation of storm-induced morphological changes in sand and gravel coasts. The following new model improvements are studied: (1) improved runup equations based on the available field data; (2) the inclusion of the uniformity coefficient (C_u = d₆₀/d₁₀) of the bed material affecting the settling velocity of the suspended sediment and thus the suspended sediment transport; (3) the inclusion of hard bottom layers, so that the effect of a submerged breakwater on the beach–dune morphology can be assessed; and (4) the determination of adequate model settings for the accretive and erosive conditions of coarse gravel–shingle types of coasts (sediment range of 2 to 40 mm). The improved model has been extensively validated for sand and gravel coasts using the available field data sets. Furthermore, a series of sensitivity computations have been made to study the numerical parameters (time step, grid size and bed-smoothing) and key physical parameters (sediment size, wave height, wave incidence angle, wave asymmetry and wave-induced undertow), conditions affecting the beach morphodynamic processes. Finally, the model has been used to study various alternative methods of reducing beach erosion. Full article

Trophic ecology is an important aspect to consider when studying interactions between species, especially in ecologically similar species. We studied the trophic ecology of three sympatric insectivorous lizards in a dune system in the Eastern Iberian Peninsula: Acanthodactylus erythrurus, Psammodromus algirus and Psammodromus edwardsianus. We obtained a total of 485 faecal samples and found 18 different prey groups. The trophic niche breath analysis showed that A. erythrurus was the most specialised species of the three. We also considered two different habitat types and, interestingly, both Psammodromus species had wider trophic niches in the more extreme habitat type where arthropod diversity is expected to be lower. Trophic niche overlaps were especially low between P. algirus and A. erythrurus, indicating resource partitioning, and higher between both Psammodromus species in the suboptimal habitat type. Our results lead to the conclusion that environmental stress could favour trophic generalism (increased trophic niche breadth). This is a very interesting result, especially in the context of climate change and habitat alteration. Full article

Coastal vegetated ecosystems, including tidal marshes, vegetated dunes, and shrub- and forest-dominated wetlands, can mitigate hurricane impacts such as coastal flooding and erosion by increasing surface roughness and reducing wave energy. Land cover maps can be used as input to improve simulations of surface roughness in advanced hydro-morphological models. Consequently, there is a need for efficient tools to develop up-to-date land cover maps that include the accurate distribution of vegetation types prior to an extreme storm. In response, we developed the RUSH tool (Rapid remote sensing Updates of land cover for Storm and Hurricane forecast models). RUSH delivers high-resolution maps of coastal vegetation for near-real-time or historical conditions via a Jupyter Notebook application and a graphical user interface (GUI). The application generates 3 m spatial resolution land cover maps with classes relevant to coastal settings, especially along mainland beaches, headlands, and barrier islands, as follows: (1) open water; (2) emergent wetlands; (3) dune grass; (4) woody wetlands; and (5) bare ground. These maps are developed by applying one of two seasonal random-forest machine learning models to Planet Labs SuperDove multispectral imagery. Cool Season and Warm Season Models were trained on 665 and 594 reference points, respectively, located across study regions in the North Carolina Outer Banks, the Mississippi Delta in Louisiana, and a portion of the Florida Gulf Coast near Apalachicola. Cool Season and Warm Season Models were tested with 666 and 595 independent points, with an overall accuracy of 93% and 94%, respectively. The Jupyter Notebook application provides users with a flexible platform for customization for advanced users, whereas the GUI, designed with user-experience feedback, provides non-experts access to remote sensing capabilities. This application can also be used for long-term coastal geomorphic and ecosystem change assessments. Full article

Plastic pollution in marine environments is a globally recognized concern that poses ecological and economic threats. While 80% of plastic originates from land, 20% comes from sea-based sources like shipping and fishing. Comprehensive assessments of fishing-related plastics are limited but crucial for mitigation. This study analyzed the distribution and temporal evolution of three fishing-related items (EPS fish boxes, fragments, and buoys) along the Bocassette spit in the northern Adriatic Sea, a region with high fishing and aquaculture activity. UAV monitoring (November 2019, June/October 2020) and structured interviews with Po Delta fishermen were conducted. The collected debris was mainly EPS, with boxes (54.8%) and fragments (39.6%). Fishermen showed strong awareness of degradation, identifying plastic as the primary litter type and reporting gear loss. Litter concentrated in active dunes and the southern sector indicates human and riverine influence. Persistent items (61%) at higher elevations suggest longer residence times. Mapped EPS boxes could generate billions of micro-particles (e.g., ~10¹³). The results reveal a complex interaction between natural processes and human activities in litter distribution. This highlights the need for integrated management strategies, like improved waste management, targeted cleanup, and community involvement, to reduce long-term impacts on vulnerable coastal ecosystems. Full article

Changes in land use and agricultural practices have altered the resilience of plant communities and can lead to the emergence of invasive species. One of these is the perennial grass species Bothriochloa ischaemum (L.) Kleng., whose diversity-reducing effects are known from several studies. Our exploratory questions were as follows: How does the presence of B. ischaemum affect the diversity and ratio of the species of sandy grasslands? To what extent does this diversity change depend on site characteristics? The supporting studies were carried out in five low-lying sand dune slacks and six relatively higher areas in the upper-intermediate part of the dunes and on an abandoned old field located in the Hungarian Great Plain in the Carpathian Basin. The cover of vascular plant species was recorded in all sampling sites in twelve 2 by 2 m plots, and the dataset was analysed using agglomerative cluster analyses and a non-parametric Kruskal–Wallis test. Five significantly different groups were identified, separating the vegetation types of the sides of the sand dunes, the vegetation types of the dune slack and the old field, and a Stipa borysthenica Kolkov ex Prokudin-dominated vegetation type. Our results suggest that B. ischaemum is only present as small tussocks on the drier, more exposed sides of dunes, with 3.9–24.2% average coverage; is less able to outcompete Festuca vaginata Waldst. et Kit. ex Willd. and S. borysthenica; and is only able to form large tussocks mainly in the lower dune slacks, with 45.6–79.5% average coverage. Here, in the wetter areas, it achieves high cover with a considerable accumulation of litter, and it becomes a dominant species in this association. The diversity-reducing effect of B. ischaemum on old-field grasslands depends on the age of the site and on the stability of the vegetation. Full article

The discovery of an Aurignacian lithic assemblage along the northern coast of the Island of Lemnos in the northeastern Aegean Sea has opened new perspectives on the study of the beginning of the Upper Paleolithic in this region. The site is located some 93 m from the present seashore. It was discovered in the summer of 2020, ca. 2 km west of the Pournias Bay. The lithics were exposed in a well-defined oval concentration, ca. 25 × 10 m wide, buried by a Holocene sand dune. They were uncovered following sand removal by a bulldozer for the construction of a parking lot. The knapped stones are made almost exclusively from hydrothermal siliceous rocks, a raw material available on the island. Raman spectroscopy and optical observations confirmed that this raw material is chalcedony. The surfaces of most artefacts are weathered due to deposition in an environment rich in marine salt, which does not preserve any organic material suitable for radiocarbon dating. The knapped stone assemblage consists of diagnostic artefacts, among which are different types of carinated end scrapers, cores, and a few bladelets. The discovery of an Aurignacian site plays an important role in the study of the Paleolithic peopling of Lemnos and the Northeast Aegean in general, a period that was previously known only through Epipaleolithic sites discovered and excavated mainly along the eastern coast of the island. Full article