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Stalter, R. and Lonard, R.I., 2024. Biological flora of sand dunes on the northwest Pacific coastline of North America: Ammophila arenaria (L.) Link and Ammophila breviligulata Fernald. Journal of Coastal Research, 40(5), 994–1000. Charlotte (North Carolina), ISSN 0749-0208. Ammophila arenaria, native to European coastal dunes, was initially introduced on the Pacific coast of North America in 1868, while A. breviligulata was introduced to temperate regions along the Pacific coast in 1935. Both rhizomatous taxa are often dominant on coastal foredunes. Ammophila arenaria has short, thick rhizomes, while A. breviligulata has a spreading rhizome system. Both species have been introduced for sand stabilization and shoreline protection. The primary method of reproduction for both taxa is fragmentation of rhizomes. Ammophila breviligulata aggressively competes with A. arenaria and is now dominant over A. arenaria at many sites. The introduction of A. arenaria and A. breviligulata has contributed to dense cover on foredunes and a concomitant decline of native plants and animals, especially those dependent on open sand habitats. Ammophila breviligulata successfully competes with A. arenaria, which has reduced dune heights, increasing the number of areas vulnerable to storm surges and dune erosion. [ABSTRACT FROM AUTHOR]

Wang, P.; Royer, E.L.; Jackson, K., and Gutierrez, S., 2024. Impacts of Hurricane Ian along the low-lying southwest Florida coast (USA) in 2022: Lessons learned. Journal of Coastal Research, 40(5), 827–851. Charlotte (North Carolina), ISSN 0749-0208. Hurricane Ian made landfall in the low-lying, densely populated, and developed southwestern Florida coast on 28 September 2022 as a large and slow-moving category 4 hurricane. Various U.S. federal and state agencies collected a large and comprehensive data set, including pre- and poststorm airborne LIDAR topography, in situ water level and wave measurements at numerous locations before, during, and after the storm, and poststorm high-water marks over a large area. This study reports results from a series of poststorm field investigations including ground observations of beach-dune erosion and deposition, catastrophic damage to various infrastructure, and widespread distribution of non-biodegradable materials washed into the estuary and numerous mangrove islands. Hurricane Ian induced large-scale inundation in low-lying southwest Florida, submerging all the barrier islands bordering Charlotte Harbor estuary, all the islands within the estuary, and up to 5 km into the mainland. Dense tree-type vegetation limited the landward penetration of beach-dune erosion and overwash deposition along the barrier islands. Net sand-volume loss from the beach-dune system ranged 10–25 m3/m and was controlled by the deep submergence of the system during the peak of the storm. The extremely high storm surge of up to 5.2 m above mean sea level generated by Hurricane Ian caused severe damage to the built environments over a large area. High storm waves superimposed on the elevated water level, reaching 1.2 m at the seaward edge of vegetated dunes, contributed to the destruction along the barrier islands. Hurricane Ian distributed a tremendous amount of non-biodegradable artificial debris over a large area and into sensitive natural environments, including numerous mangrove islands, barrier-island interior wetlands, and the estuary waterbody. Measures to prevent materials such as single-use plastics, insulation fibers, and household appliances from being washed into sensitive environments should be a significant part of prestorm preparation. [ABSTRACT FROM AUTHOR]

Greipsson, S.; Stover, K.; Whitney, S., and McElroy, T., 2024. Arbuscular mycorrhizal fungi and soil fungi associated with Uniola paniculata L. (sea oats) on restored and natural sand dunes on the Georgia Coast, U.S.A. Journal of Coastal Research, 40(5), 875–886. Charlotte (North Carolina), ISSN 0749-0208. Coastal sand dunes are fragile ecosystems that serve as natural defenses to protect barrier islands and the adjacent mainland during severe storms. A high frequency of disturbances may result in dune erosion. Several strategies have been used for coastal restoration; however, previous practices often lack the connection between plants and below-ground microbial communities. Symbiotic arbuscular mycorrhizal fungi (AMF) are beneficial in supplying a range of limiting nutrients to the host plant while improving dune stability. This study assessed the diversity of the indigenous AMF and soil fungal communities associated with Uniola paniculata L. (sea oats) on natural dunes and restored dunes at Jekyll and Tybee Islands on U.S. Georgia's coast. The phosphorus (P) concentrations of dune sand were also analyzed. At each site, samples were collected from 10 dune ridges that were randomly selected along a 100-m transect where sea oats were growing. The genomic DNA was extracted from 60 sand and sea oats root samples. A total of 13 amplicon sequence variants of AMF were identified; seven were classifiable to the species level. The most abundant genera of AMF were Glomus; the most abundant species were unclassified Glomus spp., followed by Glomus custos and G. deserticola. Using the Sorensen-Dice coefficient, the study showed that AMF assemblages of the natural dunes of both sites shared a high similarity (0.73). However, AMF assemblages of the Jekyll Island natural site had no (0) similarity to Jekyll Island restored site 1. The greatest number of classes of soil fungi were found at Jekyll Island's restored site 1 (18 classes); conversely, the lowest number was found at Jekyll Island's natural site (nine classes). Natural dunes contained significantly greater levels of P in the sand compared with restored dunes. These findings demonstrate the need to manage sand material and AMF assemblages during coastal dune restoration. [ABSTRACT FROM AUTHOR]

This article provides information about Wyoming jade, specifically the two types of rock it is composed of: jadeitite and nephrite. Nephrite is the more common type and is known for its toughness and ability to be carved into delicate shapes. Wyoming jade is found in various mountain ranges in central and eastern Wyoming, particularly in areas where crustal plates have collided. The formation of jade in this region is believed to be a result of hydrothermal fluids interacting with amphiboles and crystallizing rapidly in a tectonically active environment. Detrital jade, or jade float, is also found in alluvial deposits downstream from primary deposits. [Extracted from the article]

Despite their undeniable potential for promoting sustainability in construction materials, the characteristics of recycled aggregates (RCA), seawater, and sea sand may vary significantly, thereby affecting their use in structural concrete. This study exploits these materials to investigate their performance in producing sustainable concrete and establishing its mechanical and fracture behavior. The so produced material, referred to as seawater sea sand recycled aggregate concrete (SSRAC) could lend a hand in widening the usage of RCA and sea sand in a variety of applications where the use of ever-depleting natural materials as concrete constituents becomes an issue. Consequently, the variables of the study include the type of water (fresh versus seawater), type of coarse aggregate (RCA versus natural coarse aggregate, NCA), and the type of fine aggregate (dune sand versus sea sand). For each water type, three concrete mixtures are produced using NCA-dune sand, RCA-dune sand, and RCA-sea sand combinations. Analyses of the mechanical characteristics of the concrete, including compressive strength, flexural strength, modulus of elasticity, and fracture toughness, were conducted based on experimental tests. X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses were also conducted on the designed specimens to investigate their microstructure. In terms of fracture characteristics, the use of seawater resulted in improvement in the fracture toughness. The use of recycled aggregate along with seawater resulted in improved compressive strength. However, natural aggregate concrete (NAC) showed higher flexural strengths than recycled aggregate concrete (RAC). The results also revealed that the addition of sea sand had a detrimental impact on all mechanical characteristics. Thus, optimizing the concrete composition in which the investigated materials partially replace the conventional concrete constituents is required in order to consider alternative constituents to generate sustainable concrete for practical applications. [ABSTRACT FROM AUTHOR]

Purpose: Wind-induced erosion is a serious problem that yields soil degradation and environmental pollution. Biocementation technologies have shown potential for sand fixation and wind erosion control in deserts and arid regions. The topic of this study is to investigate the effectiveness of biocementation against wind-induced erosion with different treatment processes. Methods: Biocementation was achieved through soybean-urease induced calcium carbonate precipitation. Three different volumes of treatment solution were used to treat sand specimens by spraying, mixing and the combination methods in this study. The characteristics of sprayed and mixed crust were shown, and the properties of all the biotreated specimens including CaCO3 distribution, wind erosion rate, and penetration resistance were measured. Results: The carbonate content in the soil increased with the amount of treatment solution. At the same dosage, the spraying method concentrated 1.0%-1.4% CaCO3 in the surface soil, while the mixing method generated 0.8% CaCO3 in a uniform spatial distribution. The top-concentrated CaCO3 resulted in a lower initial wind erosion rate of the sprayed specimen. The overall reinforcement of the soil by the mixing method produced higher penetration resistance and inhibited the development of wind erosion. The combination of the two methods increased penetration resistance to 200 N and reduced the wind erosion rate to almost 0 g·m−2·min−1. Conclusion: The spraying and mixing methods induced different distribution patterns of CaCO3 precipitations in soil, leading to varying biocementation effectiveness. To resist severe and continuous wind-induced erosion, a combination of the two methods can be considered to improve the uniformity and strength of biocementation within a certain depth of the soil. [ABSTRACT FROM AUTHOR]

Understanding long-term changes in topography and topsoil grain composition is crucial for the management of agricultural landscapes, especially in areas prone to wind erosion. This study investigates long-term changes in topography and topsoil grain composition within an agricultural landscape in south-western Slovakia. To analyse topographic changes over time, we used high-precision positioning measurements and airborne laser scanning to create digital terrain models (DTM) for the years 2011, 2017 and 2020. To assess changes in soil grain composition, we performed grain size analyses on soil samples collected during three different periods: M1 (1961-1970), M2 (2009-2015) and M3 (2015-2016). Changes in soil texture were evaluated to understand the impact of wind erosion on soil composition. The influence of windbreaks was also analysed by comparing the accumulation and deflation processes. The results showed significant changes in both topography and soil texture over the study period. The DTMs showed marked differences in the accumulation and deflation processes, highlighting areas affected by wind erosion. Comparisons of soil samples showed a shift in dominant soil types from loam and clay loam to silty loam, highlighting the effects of wind erosion. Analysis revealed a decrease in clay and silt content and an increase in sand content, indicating wind-induced soil degradation. The presence of windbreaks played a crucial role in reducing soil erosion by reducing wind speed, promoting soil accumulation and stabilising the landscape up to 80 m windward and 20 m leeward. The study highlights the complex interplay of climate and wind factors in shaping topography and soil properties and emphasises the protective role of windbreaks in agricultural landscapes over time. Our results show that wind erosion significantly alters soil texture, which can affect agricultural productivity. However, windbreaks have proven to be an effective measure in reducing soil erosion and maintaining soil quality. [ABSTRACT FROM AUTHOR]

In rivers worldwide, multiple scales of dunes coexist. It is unknown how the larger, primary dunes interact with secondary bedforms that are superimposed. We test the hypothesis that streamwise variability in the sediment flux inferred from the downstream migration of secondary bedforms explains migration of the host dune, based on bathymetric data from a lowland, sand‐bedded river. Results indicate that transport estimated from secondary bedform migration increases along the host dune stoss, eroding the stoss slope. When the superimposed bedforms disintegrate at the primary lee slopes, results indicate that all sediment transport associated to secondary bedform migration is arrested in the lee of the host dune, explaining migration of the host dune. When secondary dunes persist however, only part of the sediments transport linked to secondary dunes contributes to the migration of the host dune. This study gives novel insight into the fundamental mechanisms controlling the kinematics of compound dunes. Plain Language Summary: Dunes are undulating features that can develop on a sandy river bed. They migrate downstream as a result of sediments moving from the stoss, the upstream facing slope of the dune, to the lee, the downstream slope of the dune. Sometimes, multiple scales of dunes coexist, where trains of small dunes travel over larger dunes. In this study we investigate how two dune scales interact and how they contribute to the downstream transport of bed sediments. This is done based on a series of field campaigns in the River Waal. The results indicate that migrating secondary dunes contribute to the displacement of the host dune, the dune over which they migrating. In some cases, secondary dunes travel over the host dune stoss and disintegrate at the host dune lee, depositing sediment there. In other cases, secondary dunes travel over the full length of the host dune toward the next, downstream dune. In this case, part of the sediments transport linked to the secondary dunes contributes to the downstream displacement of the host dune, and part of the sediments are transported to the next primary dune. Key Points: Secondary bedforms are omnipresent and are key to understanding primary dune behaviorSediment transport rates linked to migration of superimposed river bedforms increase over the host dune stoss and decrease over the lee sideSecondary bedforms control migration of the host dune, both when they persist over the host dune and when they disintegrate at the lee side [ABSTRACT FROM AUTHOR]

River bedforms and their deposits—fluvial cross strata— respond to floods. However, it is unclear if all floods are equally represented in cross strata. Here, using a series of physical experiments in which bedforms were subjected to equivalent flood magnitudes over varying durations, we demonstrate the existence of a lower bound on flood durations that are represented in cross strata. We show that the scour depths and preserved set thickness are indistinguishable from baseflow conditions when the rising‐limb duration of floods is shorter than the baseflow‐equilibrated bedform turnover timescale—time required to displace the volume of a single bedform at baseflow conditions. In contrast, scour depth and preserved set thickness distributions deviate from baseflow conditions when flood rising‐limb duration exceeds the baseflow‐equilibrated bedform turnover timescale, causing preferential preservation of falling‐limb bedform dynamics. Our work provides a previously unrecognized quantitative bound on flood durations that are represented in fluvial cross strata. Plain Language Summary: Bedforms are routinely found on sandy riverbeds and their deposits, called fluvial cross strata, are the fundamental building blocks of river deposits. It has long been hypothesized that bedforms respond to floods by changing their shape and speed. In addition, fluvial cross strata are hypothesized to record past floods, thus, providing a key window into past hydrologic variability. However, it is unclear if floods of all durations are equally likely to be represented in bedform morphology and fluvial cross strata. Here, we investigate how floods of different durations are recorded in fluvial cross strata using four physical experiments of bedform evolution. We examine changes in bedform morphology (height, length, speed) and preservation with floods of equal magnitude but varying durations and compare the results with a control experiment with steady water and sediment discharge. Our results reveal a previously unrecognized lower limit on preserved flood duration in cross strata, corresponding to the time required to move a single bedform one wavelength (turnover timescale) in baseflow conditions. Only floods with durations longer than the turnover timescale led to identifiable changes in bedform morphology and fluvial cross strata. These findings advance our ability to better interpret geological records of past floods. Key Points: Experiments show that baseflow‐equilibrated bedform turnover timescale sets the lower bound on preserved flood duration in cross strataFloods with a duration less than this lower bound do not cause a detectable change in preserved set thickness and scour‐depth distributionFloods with duration longer than the lower bound cause scour‐depth deepening and preferential preservation of falling‐limb deposits [ABSTRACT FROM AUTHOR]

Aeolian sandy soil and loess soil of the Mu Us Sandy Land are used as the research material in this study to investigate the effect of soil compounding on the improvement of aeolian sandy soil and to provide a feasible approach for sand prevention and sand control. In particular, loess soils were compounded at 0%, 20%, 40%, 60%, 80%, and 100% by volume percentage of the compounded soils. The improvement benefits of compounded soils on their textural properties, water-holding capacity, and fertilizer-retention capacity at different blending ratios were evaluated. The results showed that following the compounding of aeolian sandy and loess soils, with the increase of the loess proportion, the texture type of the compounded soil transforms from sandy soil to loamy sandy soil to sandy loam to loamy soil to powdery loam. Moreover, granular gradation was observed, the bulk density gradually decreased, the capillary porosity gradually increased, and the performance of water- and fertilizer-holding properties gradually increased and strengthened. The spatial variability of compounded soil bulk density, capillary porosity, and the water-holding and fertilizer-retention properties was almost entirely controlled by the proportion of loess soil. A theoretical basis is provided in this study for aeolian sandy soil improvement in the Mu Us Sandy Land that can be extended to similar areas, providing a feasible sand management approach. [ABSTRACT FROM AUTHOR]

Spatial accurate mapping of land susceptibility to wind erosion is necessary to mitigate its destructive consequences. In this research, for the first time, we developed a novel methodology based on deep learning (DL) and active learning (AL) models, their combination (e.g., recurrent neural network (RNN), RNN-AL, gated recurrent units (GRU), and GRU-AL) and three interpretation techniques (e.g., synergy matrix, SHapley Additive exPlanations (SHAP) decision plot, and accumulated local effects (ALE) plot) to map global land susceptibility to wind erosion. In this respect, 13 variables were explored as controlling factors to wind erosion, and eight of them (e.g., wind speed, topsoil carbon content, topsoil clay content, elevation, topsoil gravel fragment, precipitation, topsoil sand content and soil moisture) were selected as important factors via the Harris Hawk Optimization (HHO) feature selection algorithm. The four models were applied to map land susceptibility to wind erosion, and their performance was assessed by three measures consisting of area under of receiver operating characteristic (AUROC) curve, cumulative gain and Kolmogorov Smirnov (KS) statistic plots. The results revealed that GRU-AL model was considered as the most accurate, revealing that 38.5%, 12.6%, 10.3%, 12.5% and 26.1% of the global lands are grouped at very low, low, moderate, high and very high susceptibility classes to wind erosion hazard, respectively. Interpretation techniques were applied to interpret the contribution and impact of the eight input variables on the model's output. Synergy plot revealed that the soil carbon content exhibited high synergy with DEM and soil moisture on the model's predictions. ALE plot showed that soil carbon content and precipitation had negative feedback on the prediction of land susceptibility to wind erosion. Based on SHAP decision plot, soil moisture and DEM presented the highest contribution on the model's output. Results highlighted new regions at high latitudes (southern Greenland coast, hotspots in Alaska and Siberia), which exhibited high and very high land susceptibility to wind erosion. [ABSTRACT FROM AUTHOR]

Introduction: The precipitation pattern has changed significantly in arid desert areas, yet it is not clear how the water use strategies of Tamarix ramosissima Ledeb. on coppice dunes along a natural precipitation gradient are affected. Methods: In this study, the hydrogen and oxygen isotope compositions of xylem water, soil water, precipitation, and groundwater were measured by stable isotope techniques in Huocheng, Mosuowan, and Tazhong. Additionally, the water use strategies of natural precipitation gradient were investigated in conjunction with the MixSIAR model. Results: The results indicated that the water sources of T. ramosissima exhibited significant variation from semi-arid to hyper-arid areas. In semi-arid areas, T. ramosissima mainly absorbed shallow, shallow-middle, and middle soil water; however, T. ramosissima shifted its primary water sources to middle and deep soil water in arid areas. In hyper-arid areas, it mainly utilized deep soil water and groundwater. In contrast, the water source contribution rate of T. ramosissima exhibited relative uniformity across each layer in an arid area. Notably, in hyper-arid areas, the proportion of groundwater by T. ramosissima was significantly high, reaching 60.2%. This is due to the relatively shallow groundwater supplementing the deep soil water content in the area. In conclusion, the proportion of shallow soil water decreased by 14.7% for T. ramosissima from semi-arid to hyper-arid areas, illustrating the occurrence of a gradual shift in potential water sources utilized by T. ramosissima from shallow to deep soil water and groundwater. Discussion: Therefore, T. ramosissima on coppice dunes shows flexible water use strategies in relation to precipitation and groundwater, reflecting its strong environmental adaptability. The findings hold significant implications for the conservation of water resources and vegetation restoration in arid areas. [ABSTRACT FROM AUTHOR]

This article is an editorial that discusses the development and ecological functions of biological soil crusts (biocrusts). Biocrusts are composed of microorganisms and play important roles in soil stabilization, microbial diversity, and ecosystem development. The editorial emphasizes the need for further research on biocrust communities and their impact on landscape-scale outcomes. It also highlights the ecological functions of biocrusts, such as reducing erosion and influencing biogeochemical cycles. The article concludes by discussing the importance of understanding biocrusts for ecological restoration and land management strategies. Another document provides a list of references for articles related to biological soil crusts, covering topics such as land degradation neutrality, ecological restoration, and the impact of biocrusts on microbial communities. The articles also explore the composition and response of biocrusts to climate change and physical disturbance, as well as their effects on soil properties and metabolic response to hydration. [Extracted from the article]

Aeolian concentration of iron-titanium oxides (black sand) is a common phenomenon on coasts around the world but associated aeolian detrital gold is relatively rare. In contrast, Holocene and active dunes at Waipapa beach on the coast of the southern South Island of New Zealand host aeolian black sand layers with locally abundant finely particulate (<200 µm) gold and platinum, some of which have been mined historically. Aeolian concentration of black sand, gold and platinum is driven by strong prevailing westerly winds (gusts >100 km/h) on annual or decadal time scales. Holocene fluvial recycling of aeolian sands has been important in upgrading the black sand, gold, and platinum contents. Surf concentration of black sand on the beach is minor and merely feeds the aeolian system, and this differs from other beach gold deposits around the world, which are surf-dominated. Most of the Waipapa beach gold (>90%) has flaky morphology with abundant superficial transport-related deformation reflective of fluvial transport, probably down the nearby Mataura River (∼200 km transport) between Miocene and Holocene. Minor distinctive wind-sculpted toroidal gold, and the platinum, arrived from the west (∼300 km transport) via the Waiau River and Foveaux Strait. [ABSTRACT FROM AUTHOR]

This article presents a study on the wind-sand dynamics of blowouts in the Xilingol sandy grassland in Inner Mongolia, China. The study investigates the changes in airflow and sediment transport within the blowouts. The results show that the wind direction inside the blowout is influenced by the direction of the incoming wind, and the rate of wind speed acceleration and sand transport is primarily influenced by wind direction and wind speed. The study provides insights into the formation and development of blowouts and their impact on land resources and human livelihoods. [Extracted from the article]

This paper presents a comprehensive three-dimensional numerical investigation of horizontal square anchors embedded in geogrid-reinforced sand. Prior experimental studies have demonstrated notable enhancements in anchor uplift capacity when placed below geogrid reinforcement in soil. However, these results are limited to small anchor plates tested in laboratory conditions with over-reinforced sand. In contrast, this study focuses on large field-scale anchors and explores the influence of anchor width, embedment depth, reinforcement size, stiffness, and tensile strength on uplift capacity. The findings reveal that the optimal size for geogrid reinforcement is three times the anchor width. A diminishing improvement in uplift capacity with increasing anchor width was observed. Additionally, deeper anchor embedment reduces the uplift capacity improvement in geogrid-reinforced sand. The geogrid reinforcement is found to be more efficient in the case of shallow anchors placed in loose sand. The major contribution of this paper lies in the response analysis of large anchors and providing a better understanding of the uplift mechanism in geogrid-reinforced sand. • This paper presents a three-dimensional numerical investigation of large field-scale horizontal square anchors embedded in geogrid-reinforced sand. • The findings reveal that the optimal size for geogrid reinforcement is three times the anchor width (B) in contrary to the 5B value reported in the previous literature. • A diminishing improvement in uplift capacity with increasing anchor width was observed. • Deeper anchor embedment reduced the uplift capacity improvement in geogrid-reinforced sand. • The geogrid reinforcement is found to be more efficient in the case of shallow anchors. [ABSTRACT FROM AUTHOR]

To enhance the mechanical properties and stability of desert railway embankments, the utilization of geogrids has proven to be an effective measure. The article conducted field tests and discrete element simulations to thoroughly examine the static performance of embankments reinforced with geogrids. The study systematically explored the macroscopic and microscopic characteristics of the geogrid-reinforced embankment under static loading. Various factors were investigated, including the horizontal laying arrangements and depth to the top layer of the geogrid, as well as key design parameters such as the number of geogrid layers, geogrid width, and vertical spacing between geogrid layers. The findings indicate a progressive enhancement in the ultimate bearing capacity of the embankment with an increase in both the number of geogrid layers and the geogrid width. Conversely, there is a decrease in ultimate bearing capacity as the depth to the top layer increases. In comparison to unreinforced embankments, reinforced embankments exhibit a reduced contact anisotropy, signifying that the geogrid effectively disperses static loads, resulting in a more uniform contact distribution. The geogrid restrains both displacement and rotation of the aeolian sand, and this restraining effect progressively strengthens with an increase in the number of geogrid layers or the geogrid width. The research findings can serve as a reference for the design and application of aeolian sand railway embankments. • We conducted triaxial tests on aeolian sand, single rib strip tests on geogrids, and field tests of geogrids reinforced aeolian sand embankments. • Additionally, we developed a two-dimensional discrete element embankment model to investigate the impact of geogrid parameters on the macro and micro performance of reinforced embankments. [ABSTRACT FROM AUTHOR]

Sand rice (Agriophyllum squarrosum), widely distributed in Central Arid Asia and prevalent in the sand dunes of northern China, presents a promising potential as a climate‐resilient crop. The plasticity of hypocotyl growth is the key trait for sand rice to cope with wind erosion and sand burial, ensure seedling emergence, and determine plant architecture. In this study, we assessed the overall hypocotyl phenotype of six sand rice elite lines, which were collected from different regions of northern China, and selected by our group over past decade through common garden trials. Significant phenotypic variations were observed in thousand‐seed weight (TSW), seedling emergence percentage, hypocotyl length and diameter, and seedling fresh weight among the lines. The elite line Aerxiang (AEX) exhibited excellent agronomic performance with superior and synchronous emergence, and high survival percentage, distinguishing itself as a prime candidate for further large‐scale cultivation. Contrastingly, the lines from the arid regions showed markedly lower performance. Partial Least Squares Path Modeling (PLSPM) was used to assess the impact of seed provenance climate factors, including annual mean temperature (AMT) and annual mean precipitation (AMP), on trait variability among lines. The findings indicate a significant correlation between climate factors and hypocotyl length, highlighting the intricate adaptation of sand rice to local climate. The comprehensive understanding of the mechanisms behind phenotypic variations offers valuable insights for sand rice de novo domestication and innovative germplasm resources, and lays the foundation for ecological restoration in sandy areas. [ABSTRACT FROM AUTHOR]

Dunes are the primary geomorphological type in deserts, and the distribution of dune morphologies is of significant importance for studying regional characteristics, formation mechanisms, and evolutionary processes. Traditional dune morphology classification methods rely on visual interpretation by humans, which is not only time-consuming and inefficient but also subjective in classification judgment. These issues have impeded the intelligent development of dune morphology classification. However, convolutional neural network (CNN) models exhibit robust feature representation capabilities for images and have achieved excellent results in image classification, providing a new method for studying dune morphology classification. Therefore, this paper summarizes five typical dune morphologies in the deserts of western Inner Mongolia, which can be used to define and describe most of the dune types in Chinese deserts. Subsequently, field surveys and the experimental collection of unmanned aerial vehicle (UAV) orthoimages for different dune types were conducted. Five different types of dune morphology datasets were constructed through manual segmentation, automatic rule segmentation, random screening, and data augmentation. Finally, the classification of dune morphologies and the exploration of dataset construction methods were conducted using the VGG16 and VGG19 CNN models. The classification results of dune morphologies were comprehensively analyzed using different evaluation metrics. The experimental results indicate that when the regular segmentation scale of UAV orthoimages is 1024 × 1024 pixels with an overlap of 100 pixels, the classification accuracy, precision, recall, and F1-Score of the VGG16 model reached 97.05%, 96.91%, 96.76%, and 96.82%, respectively. The method for constructing a dune morphology dataset from automatically segmented UAV orthoimages provides a reference value for the study of large-scale dune morphology classification. [ABSTRACT FROM AUTHOR]

Background and aims: Windblown sand movements, i.e., wind denudation and sand burial, pose a strong selective pressure on dune vegetation. Dune plants commonly receive repeated wind denudation or sand burial. Therefore, simultaneously examining the role of sand movement intensity and frequency in shaping dune vegetation is critical for dune biodiversity conservation and ecological restoration. However, studies of this nature are rare. Methods: We studied the integrated effects of sand movement intensity and frequency on the seedling performance of a dominant semi-shrub, Artemisia ordosica, in the Mu Us sandland. We subjected A. ordosica seedlings to a total intensity of 10 cm wind denudation or sand burial treatments conducted once, twice or four times. Key results: We found, given that the total intensity of sand movement remains the same, increasing frequency and decreasing intensity per time largely improved seedling survival. Furthermore, increasing frequency and decreasing intensity per time significantly alleviated the negative effects of wind denudation, although such alleviation effect was not detected for sand burial. Seedlings of A. ordosica increased specific leaf area, root length, and biomass allocation to root to adapt to wind denudation, while they developed adventitious roots to adapt to sand burial. Conclusions: Our results demonstrate that a single heavy sand movement is more detrimental than multiple light ones to the performance of A. ordosica seedlings. Our findings suggest that windproof measures to prevent severe sand movements is necessary to allow the establishment of A. ordosica during the dune restoration process. [ABSTRACT FROM AUTHOR]

Hurricane Fiona made landfall as an extra-tropical storm along the north shore of Prince Edward Island (PEI), Canada, in October 2022. The state of the beach and dune immediately before and after the storm was captured through the Coastie citizen science beach and dune photo monitoring initiative, as part of the global CoastSnap Community Beach Monitoring program. Coastie monitoring sites within Prince Edward Island National Park (PEINP) revealed extensive dune scarping, capturing a 12–17 m retreat of the foredune at Brackley and Cavendish Beaches. Using foredune scarp and post-storm shoreline positions, volumetric losses between 28 and 76 m3 m−1 are estimated from profiles located within the first 150 m of the stations. The average horizontal position of the projected foredune scarp position was within 2.8 m of the position identified from high accuracy unoccupied aerial system (UAS) surveys, corresponding to a mean absolute difference of 15.3 m3 m−1 or 45.3% for dune volume changes estimated from the images. Continued monitoring will yield further improvements to the volume loss estimation methodology, and insight on the timing and mechanisms of beach and dune recovery. [ABSTRACT FROM AUTHOR]

An overview of modern bed load measurement methods in rivers with fine alluvium is performed. Four groups of the methods are identified: measuring with bed load samplers, dune-tracking with a single-beam echo-sounder, dune-tracking with a multi-beam echo-sounder and measurement using acoustic Doppler current profilers. Strengths and weaknesses of each method are considered. Due to the fact that bed load transport occurs in the form of dunes the most promising methods seem to be based on the use of echo-sounders since they make it possible to take into account the integrity of bed forms directly. [ABSTRACT FROM AUTHOR]

The identification and quantification of aeolian sand contributions are essential for understanding the formation of dune fields and mechanisms of modern surface processes. In the present study, we take aeolian sand in the Otindag dune field (hereafter, often referred to as, simply, Otindag) as the research object. The dune field's immediate source is quantitatively identified based on heavy minerals and the Conservativeness Index (CI), Consensus Ranking (CR), and the Consistent Tracer Selection (CTS) method. The primary source area of the aeolian sand was found to be from the northwestern, upwind area of the Otindag (59 ± 14%), followed by the Yinshan Mountain (17 ± 10%) and the lake basin (23 ± 12%). The proposed sediment transport model elucidates that sediments from the upwind of the Otindag are directly transported from the northwest to the Otindag, where they are deposited. Materials from the southern Yinshan Mountains are carried by rivers to the southern edge of the Otindag, where they are subsequently transported by wind and ultimately deposited. The lake deposits within the Otindag also contribute to the aeolian sand supply under the influence of wind. This study demonstrates that the fingerprinting techniques of CI, CR, and CTS serve as successful strategies for conducting quantitative provenance research in dune fields. [ABSTRACT FROM AUTHOR]

Some of the most severe aeolian damage occurs along the middle reaches of the Yarlung Zangbo River in Tibet. Dust emission amounts (DEAs) are often used to assess aeolian damage; however, the research on DEAs in this area is currently almost blank. This article uses field-measured wind speed data from 2021 to 2022 in the Shannan wide valley area, combined with the Gillette dust emission estimation model to quantitatively determine the contributions of three surface types (riverbank quicksand area, foothill sand dunes, and the river floodplain vegetation area) to DEAs in the research area. The influence of surface characteristics on DEAs is analyzed and discussed. The results show the following: (1) The threshold friction velocity ( u * t ) in the riverbank quicksand area, foothill sand dunes, and the river floodplain vegetation area is 30.6 cm/s, 71.2 cm/s, and 85.6 cm/s, respectively, the threshold velocity ( u t ) is 6.1 m/s, 7.0 m/s, and 7.5 m/s, respectively, and the vegetation area is 2.8 times and 1.3 times that of the quicksand area, respectively. (2) The DEAs were in the following order: the riverbank quicksand area (652.9 t/km2) > foothill sand dunes (326.5 t/km2) > the river floodplain vegetation area (107.8 t/km2), the riverbank quicksand area is about 6.1 times that of the river floodplain vegetation area, and DEAs are a significant seasonal distribution: winter (44.7%) > spring (28.3%) > autumn (15.7%) > summer (11.3%). (3) The DEAs from the dusty weather were in the following order: blowing sand (60.2%) > sandstorms (28.6%) > gusty winds (11.2%). (4) The DEAs increase with the increase in the average wind speed greater than 6.1 m/s, but the increase rate is obviously different, which showed that Changguo and Azha are greater than Sangyesi, Duopazhang, Sangri, and Senburi. At approximately the same average wind speed greater than 6.1 m/s, the DEAs in the quicksand area are much greater than in the vegetation area. [ABSTRACT FROM AUTHOR]

The Asiatic raccoon dog (Nyctereutes procyonoides) has successfully colonized Northern, Eastern, and Central Europe, following 20th century introductions. While subject to eradication campaigns, its ecological impacts remain incompletely understood and debated. This study aims to examine the habitat preference and movement patterns of raccoon dogs in Denmark using GPS telemetry data. Habitat selection patterns were examined seasonally using Jacob's electivity index. Movement intensity (travel speed) was examined according to temporal and environmental predictors such as time of day, time of year and habitat type. Raccoon dogs showed an overall preference for peatbogs, marshes, and broadleaf tree cover, and an overall avoidance of water bodies (per se), artificial surfaces and constructions, natural material surfaces (e.g., river pebble banks, beaches, sand dunes), cultivated areas, coniferous tree cover and herbaceous vegetation, and a close to neutral selection pattern for moors and heathland. Habitat usage was generally consistent throughout the seasons for all habitat types, apart from minor shifts observed, particularly from November to February. The raccoon dog exhibited a unimodal nocturnal activity pattern throughout all seasons, with highest mean travel speeds occurring during spring and lowest during winter. Prolonged periods of higher mean daily speeds were observed during autumn. Mean speed levels also varied according to habitat type, with raccoon dogs moving slower in habitats they preferred and faster in those they did not prefer. These results indicate that raccoon dogs in Denmark adjust their habitat selection and movement patterns throughout the year, with a general preference for moist and high tree coverage areas. This information can be utilized in forecasting models for their potential future range and area use in different regions. [ABSTRACT FROM AUTHOR]

Sediment constitutes the fundamental basis for forming and evolving aeolian geomorphology. The characteristics of sediment particle size offer insights into the development and evolution of sandy terrain, making their study critical to understanding aeolian geomorphology and sand control. In this study, we combined high-density collection of surface sediments in the Uzhumqin sand dunes and GIS spatial analysis to analyze the particle size parameters and changes in the spatial distribution of surface sediments in this region. In addition, we used an end-member analysis to identify the potential sources of the sediments. The results showed that surface sediments in the Uzhumqin sand dunes had distinct spatial distributions. Medium and coarse grain sands dominated the sediments in the dunes, and the mean grain size and the sorting coefficient generally increased along the prevailing wind direction, with high values in individual areas related to factors such as material sources and vegetation cover. Skewness was strongly influenced by factors such as landform change and human activity, and spatial variability became more complex. Kurtosis and the soil fractal dimension showed generally decreasing trends along the prevailing wind direction. With dune fixation, the contents of clay and powder particles in the soil increased; the mean particle size, the sorting coefficient, and the fractal dimension of the soil gradually increased, and the skewness and kurtosis gradually decreased. The end-member analysis results indicated the existence of five end-members (EM) in the dune sediments. EM 1 was a mixed component of wind-deposited fine sands and nearby fluvial sediments. EM 2 was the main component of sediments in the study area and was the result of sorting lake sediments by wind action and by the local topography. EM 3 may be a product of river flood deposition. EM 4 and EM 5 had coarser grain sizes. EM 4 was a lake-phase sediment product influenced by topographic and vegetation cover factors, and EM 5 was primarily a river and lake sediment product modified by weathering. The sediment particle size results from the study area indicate that the sediment in the sandy region is generally coarse due to multiple factors, including topography, climate, hydrology, and human activity. Sandy material in the study area originated from nearby, with very little sand being transported from long distances. [ABSTRACT FROM AUTHOR]

Foredunes constitute a fundamental part of the coastal environment, acting as a buffer against storm erosion and natural coastal defence. Foredune size and volume play a pivotal role in determining coastal vulnerability to marine hazards, and the governing processes driving variations in foredune morphology, particularly over regional, or larger spatial scales, are still relatively poorly understood. This paper presents a regional‐scale investigation into foredune morphology along the New South Wales (NSW) coast (SE Australia), comprising not only a state‐wide inventory of foredune morphology for use in management/hazard assessment, but also testing long‐standing hypotheses and conceptual models of the physical processes that are driving, or influencing, foredune size. We applied a remote sensing protocol to 47 foredune environments, covering the length of the NSW coastline, comparing morphology (including dune height, width, shape, and volume) of established and incipient foredunes both along, and between, sandy embayments. Results, at regional spatial scales, show that the largest foredunes (volumes up to 850 m3 m−1) occur along the central coast as large, steep landforms; intermediate‐sized dunes (550–650 m3 m−1) were found on both the Mid‐north and Far North coast, and the smallest foredunes (334–380 m3 m−1) occur on the south coast as wider dunes with steep stoss slopes. Surfzone–beach state was found to be the most significant factor influencing foredune size and volume. The more energetic and more dissipative/high‐energy intermediate surfzone–beach states were correlated with larger foredunes (i.e. greater dune volume, width and crest elevation), whereas the lower‐energy surfzone–beach states generally had smaller dunes. Changes in vegetation cover, shoreline orientation and associated onshore (and alongshore) wind systems were also demonstrated to be important factors in determining foredune morphology. The largest foredunes in NSW generally occur to the north of embayments, with dune size decreasing southward with decreasing exposure to wind/wave energy. [ABSTRACT FROM AUTHOR]

We introduce a novel analytical model of the growth of barchan dunes in terms of their two flanks, from which we derive expressions for the size‐dependence of the bilateral asymmetry of these bedforms in three cases where different mechanisms dominate the growth process. Analysis of the morphology of barchans on Mars and Earth suggest that there may exist two distinct attractor states for the asymmetry distribution. By comparing our analytical results with the observations, we show that the growth of barchan dunes appears to be dominated by processes, which are proportional to the basal area or volume of the bedforms, rather than being linear to their width as is typically assumed. We propose hypotheses explaining area‐dominated growth as a result of variable wind regimes and volume‐dominated growth from collisions. These predictions appear to be in line with the available data for the terrestrial swarms and barchan‐like submarine bedforms and offer the potential of predicting patterns in inaccessible wind regimes from data on the morphology of the dunes. [ABSTRACT FROM AUTHOR]

Coastal regions globally face escalating challenges from climate change, including rising sea levels and intensified storm events. To address these threats, coastal resilience emerges as a critical paradigm advocating the integration of nature‐based solutions with traditional engineering approaches. Coastal dunes, acting as protective barriers, offer a promising avenue. This three‐year study assesses the efficacy of an artificial dune system to address local sand‐related nuisances on the adjacent seawall featuring planted marram grass in Oosteroever, Belgium. The focus is on understanding sediment accumulation, dune morphology and vegetation development. The results demonstrate a significant increase in dune height, reaching up to 2 m in the zones planted with marram grass, surpassing the height of the adjacent seawall. Comprehensive profiles and drone surveys revealed consistent dune growth of 27 m3/m, which contrasted with the substantial erosion in the adjacent unvegetated beach areas of up to 30 m3/m. One storm event caused dune toe erosion of 1.5 m3/m, but the dune demonstrated rapid recovery through natural aeolian processes. Marram grass development was not impacted by the initial planting configuration and density and was more pronounced at the perimeter edges of the dune. This study highlights the success of the 'dune‐in‐front‐of‐a‐dike' approach, offering insights for sustainable coastal resilience strategies. [ABSTRACT FROM AUTHOR]

Most natural sandy deposits contain low amounts of fine content (< 10%), which is usually anisotropic and characterized by complex microstructures. The present study investigates the influence of low silt content on the anisotropic behaviour of sand. For this purpose, 30 undrained tests were performed using a hollow cylindrical apparatus with constant α° and b values on Firoozkuh sand. The specimens had silt contents of 0, 3, 5, 7 and 10%, and the inclination angle (α°) was varied from 15° to 60°. The specimens were prepared with the dry deposition method and subjected to confining pressures of 100 and 200 kPa. The equivalent intergranular relative density parameter was then introduced in order to create a comparative basis for the specimens. The experimental results show that increasing α leads to more contractive behaviour in the pure sand. By adding silt particles to the host sand up to 5%, the peak strength of the specimen is increased (18.5%, 12% and 7.7% for α = 15°, 30° and 60°, respectively), and the strength of the specimen is decreased. It should be noted that with a silt content of 10%, the strength of the specimen was lower than that of the host sand (about 12%). On the other hand, it can be seen that with the increase of α, the influence of fine grains as an important parameter in sand-fine mixtures is decreased. [ABSTRACT FROM AUTHOR]

Barchans are eolian dunes of crescent shape found on Earth, Mars and other celestial bodies. Among the different types of barchan‐barchan interaction, there is one, known as chasing, in which the dunes remain close but without touching each other. In this paper, we investigate the origins of this barchan‐barchan dune repulsion by carrying out grain‐scale numerical computations in which a pair of granular heaps is deformed by the fluid flow into barchan dunes that interact with each other. In our simulations, data such as position, velocity and resultant force are computed for each individual particle at each time step, allowing us to measure details of both the fluid and grains that explain the repulsion. We show the trajectories of grains, time‐average resultant forces, and mass balances for each dune, and that the downstream barchan shrinks faster than the upstream one, keeping, thus, a relatively high velocity although in the wake of the upstream barchan. In its turn, this fast shrinkage is caused by the flow disturbance, which induces higher erosion on the downstream barchan and its circumvention by grains leaving the upstream dune. Our results help explaining the mechanisms behind the distribution of barchans in dune fields found on Earth and Mars. Plain Language Summary: Barchans are crescent‐shaped wind‐formed dunes that grow when the wind is roughly unidirectional and the amount of sand is limited (typically, over a non‐erodible ground). They are found in dune fields on Earth and Mars, where barchan dunes interact with each other, forming different field patterns. One first question that arises is why, in some cases, two nearby barchans do not touch each other. Is there a repulsion mechanism? In this paper, we investigate the barchan‐barchan dune repulsion by carrying out numerical computations of the motion of the fluid and each grain forming a pair of barchans. The outputs are detailed measurements of both fluid and grains, such as trajectories, forces, and mass balances, and they show that the downstream barchan shrinks faster than the upstream one. The results also show that the faster shrinkage is due to the fluid flow disturbance caused by the upstream barchan: the fluid impacts the downstream dune, increasing its erosion at the same time that it entrains further downstream part of grains coming from the upstream dune. As a result, the downstream barchan moves at the same pace or faster than the upstream dune, though receiving grains from the latter (which only loses grains). Key Points: We investigate numerically both the fluid flow and motion of grains for understanding the mechanisms behind barchan‐barchan dune repulsionWe measure the flow rate of grains and show that there is, indeed, greater erosion on the downstream barchanThe disturbed flow impacting the downstream barchan induces higher erosion (of its grains) and low accumulation (of upstream grains) [ABSTRACT FROM AUTHOR]

The Kalahari Basin in southern Africa, shaped by subsidence and epeirogeny, features the Okavango Rift Zone (ORZ) as a significant structural element characterized by diffused extensional deformation forming a prominent depocenter. This study elucidates the Pleistocene landscape evolution of the ORZ by examining the chronology of sediment formation and filling this incipient rift and its surroundings. Modeling of cosmogenic nuclide concentrations in surficial eolian sand from distinct structural blocks around the ORZ provides insights into sand's residence time on the surface. Sand formation occurred from ∼2.2 to 1.1 Ma, coinciding with regional tectonic events. Notably, provenance analyses of sand within ORZ's lowermost block where large alluvial fans are found indicate different source rocks and depositional environments than those of the eolian sands found at a higher elevation. This suggests that the major phase of rift subsidence and the following incision of alluvial systems into the rift occurred after eolian dune formation. Luminescence dating reveals that deposition in alluvial fan settings in the incised landscape began not later than ∼250 ka, and that a lacustrine environment existed since at least ∼140 ka. The established chronological framework constrains the geomorphological effects of the different tectono‐climatic forces that shaped this nascent rifting area. It highlights two pronounced stages of landscape development, with the most recent major deformation event in the evolving rift probably occurring during the middle Pleistocene transition (1.2–0.75 Ma). This event is reflected as a striking change in the depositional environments due to the configurational changes accompanying rift progression. Plain Language Summary: Early rifting stages mark the beginning of the breakup of continents, making them crucial for understanding plate tectonics and the formation of extensional landscapes. These stages involve seismic activity and create unique environments, helping to assess geological hazards and study past habitats and biodiversity. Early stages of continental rifting in the Okavango Rift Zone, centered in northern Botswana, are described in this work from the perspective of sediment dynamics by constructing a time frame for their evolution. Two major types of sediment and their corresponding time scales are studied. The older sediments are eolian sands that were formed between ∼2.2 and 1.1 million years ago and lie today on elevated structural surfaces above the incised rift. Within the subsiding rift that was significantly geomorphologically modified not earlier than 1 million years ago, sediments were deposited by alluvial fans at least since 250 thousand years ago and were followed by a lacustrine environment with alternating hydrological conditions since at least 140 thousand years ago. Key Points: Nascent continental rifting stages are reflected through sedimentological variationsEolian sand that was formed before alluvial incision into the rift is preserved on elevated surfacesDepositional environments in the incised rift have shifted into alluvial‐lacustrine conditions around the Middle Pleistocene Transition [ABSTRACT FROM AUTHOR]

The intensification of port and tourist activities in the coastal region of the northern center of Santa Catarina, Brazil, has led to urban expansion and the loss of natural ecosystems, bringing the urban environment closer to the dune regions. Birds are sensitive to these changes, but some species, such as the burrowing owl (Athene cunicularia), have shown adaptability to urban environments. The aim of this study was to analyze the behavioral patterns of the burrowing owl in different urbanized areas near the dunes and assess the impact of local urbanization on alarm emission. The study focused on the beaches of Interpraias-Balneário Camboriú, Central-Navegantes, Península-Barra Velha, and Brava-Itajaí. The data analysis involved Kruskal–Wallis and Dunn's post hoc tests to compare alarm distances, as well as calculating relative frequencies of different behaviors. Discriminant Analysis (LDA), PERMANOVA, and SIMPER were also applied. A total of 214 h of observation were conducted across the sampled beaches. The results indicated significant differences in alarm behavior distances, with Barra Velha and Itajaí standing out from the other areas, highlighting the influence of urbanization on alarm behavior. Six categories of behavior were identified: rest, alarm, body maintenance, burrow maintenance, social interaction, and foraging, with distinct frequencies observed during the day and night. Notably, the frequency of foraging behavior was significantly higher during the night. [ABSTRACT FROM AUTHOR]

Local scour poses a grave threat to bridge foundations, potentially causing catastrophic collapses. This study uses FLOW-3D with the Reynolds-Averaged Navier-Stokes model to analyze pier scour and dune formation under bridges. It focuses on submerged debris shapes near the water's surface. Results closely match experiments when specific conditions are met. The study introduces an innovative approach to debris impact assessment. Instead of traditional methods, it proposes a novel equation accounting for debris's effective area and elevation. This enhances reliability by over 20%, improving scour depth assessment in debris-laden scenarios. This advances the understanding of debris's role in local scour, benefiting bridge design and management practices. [ABSTRACT FROM AUTHOR]

The climate change and extension of human activities are shedding more stresses on ecosystems. Ecological zoning could help manage the ecosystem and deal with environmental problems more effectively. Geology and topography could affect the ecology primarily and are vital perspectives on ecological zoning. It is worth preliminarily understanding the spatial-temporal patterns of ecologicalenvironmental attributes within various geological-topographical ecological zones (GTEZs). The objective of this study was to delineate GTEZs and present a spatial-temporal analysis on soil and land surface parameters within GTEZs. Firstly, Landsat imageries, high resolution satellite imagery products, digital elevation model, regional geological map, black soil thickness, soil bulk density, meteorological data, and ground survey were collected and conducted. Secondly, GTEZs in Hailun District were delineated according to geological and topographical background. Thirdly, soil composition, and monthly land surface temperature (LST), enhanced vegetation index (EVI), net primary productivity (NPP) were derived from ground survey and Landsat imageries. Finally, spatialtemporal patterns of various ecological-environmental attributes within different GTEZs were preliminarily revealed and analyzed. Results show that sand alluvial plain zone and silt-clay undulating plain zone mainly possess thick soil with finemedium granule and higher bulk density, and are mainly covered by crops and grass, vegetation flourish the most in August with the highest monthly EVI and NPP. While the sand-conglomerate hill zone, sandstone hill zone, and granite hill zone possess relatively thin soil with medium-coarse granule and lower bulk density, and are mainly covered by forest, vegetation flourish the most in June and July, and has the highest yearly total NPP. With thinner soil thickness and higher NPP, hill zones tend to have more vulnerability to disturbance and more contribution to carbon neutrality target. [ABSTRACT FROM AUTHOR]

Sediment grain size characterization is one of the main components of aeolian geomorphology research. Sand particle size can determine the basic form of sand movement. The distribution and form of grain size parameters of different types of sediments were calculated using six surface types of sediments around Qixing Lake in the Kubuqi Desert: Mobile dune Semi-fixed dune Fixed dune Lakeshore terrace Wetland and Grassy flat wetland The results showed that the surface sediments were mainly composed of medium sand and fine sand, and all types were negatively skewed. The differentiation pattern of the saltation component and suspended component of the surface sediment is characterized by a twostage pattern. The percentage contribution of suspended components in lakeshore terraces, wetlands, and Grassy flat wetlands (total average 21.07%) is more than twice that of mobile dunes, semifixed dunes, and fixed dunes (total average 9.47%). This suggests that mobile dunes, semi-fixed dunes, and fixed dunes are not the main contributing surface type of suspended material in the Qixing Lake area. [ABSTRACT FROM AUTHOR]

Tamarix ramosissima has an important role in stabilizing sand dunes in desert ecosystems. Understanding the water use strategies of T. ramosissima is essential to understand its adaptations on coppice dunes. We utilized the stable isotopes δ2H and δ18O in soil water, groundwater, and xylem water to identify monthly differences in water sources. Additionally. we explored rooting depth using 2H2O as an artificial tracer. In May, T. ramosissima derived 75% of its water from shallow and middle soil layers. In July, it absorbed 90% water from middle and deep soil layers. In August and September, it acquired approximately 80% of its water from deep soil layers. The labelling using 2H as an artificial tracer indicated that the root system of T. ramosissima could reach depths >500 cm in the coppice dunes. 2H absorption was observed at depths of 100, 200, 300 and 400 cm. Soil water is the dominant water source for T. ramosissima in the coppice dunes because groundwater is at depths >30 m. The flexible water‐use strategies of T. ramosissima enable it to effectively utilize different available water sources to adapt to the arid environment. These findings improve our understanding of water uptake patterns and drought adaptation strategies of T. ramosissima in the coppice dunes of desert ecosystems. [ABSTRACT FROM AUTHOR]

The maintenance of biological diversity is frequently enhanced in a heterogenous landscape by some level of disturbance. Thus, when a landscape becomes stabilized and homogenized through the spread of an invasive plant species, there may be consequences for native biodiversity, particularly for those biotas that depend on the pre‐existing, natural disturbance regime of that landscape. At Long Point, Ontario, Canada, a sandspit in Lake Erie, the community of anuran amphibians experienced the co‐incidence of 2 major disturbance events, 1 anthropogenic and 1 natural: an intervention to remove the invasive form of the common reed (Phragmites australis australis) and a spate of extensive dune washouts caused by high water levels and storms. As a result of the unequal distribution of disturbance in the landscape, different areas were affected by only the dune washouts, only the common reed treatment, both disturbances, or neither disturbance. From May to August 2021, we explored how the disturbances affected the resident frog and toad species habitat associations in the 4 different disturbance conditions in the landscape. By means of minnow traps, acoustic surveys, and visual surveys, we determined that the dune washouts had a greater influence on resident anurans than the common reed treatment. Ranid frogs (Ranidae) tended to inhabit non‐washout sites, whereas Fowler's toads (Anaxyrus fowleri) congregated in the newly formed, sand flats and shallow, de‐vegetated pools resulting from the washouts. Neither ranid frogs nor Fowler's toads demonstrated avoidance of the sites affected by the herbicide treatment and mechanical rollover of the common reed. This evidence of species sorting, which enables multiple species to persist in a dynamic and heterogeneous landscape, suggests that wildlife management in aid of threatened species recovery may find success by encouraging natural disturbance regimes in dynamic landscapes. Future management endeavors should consider refraining from complete dune stabilization in these landscapes to allow the natural washouts to occur at a higher frequency, while ensuring the continued effectiveness of the invasive common reed eradication. [ABSTRACT FROM AUTHOR]

Habitat destruction and fragmentation are one of the main drivers of pollinator decline and biodiversity loss in general. However, the exact effects of habitat fragmentation on pollinator communities are still poorly understood, and it remains unclear which patch characteristics are most important in driving pollinator diversity and community composition.In this study, we inventoried plant and insect diversity in a total of 19 fragmented dune slacks in Belgium. Specifically, we assessed the effects of dune slack area and connectivity on plant and pollinator diversity and community composition. Additionally, we investigated to what extent plant diversity had an impact on insect pollinator communities.The results indicated that species richness of both plants and insects was significantly related to patch area, whereas patch connectivity only had a significant effect on plant diversity. Nestedness analyses showed that plant communities of small dune slacks were a subset of the communities of large patches, but no such patterns were found for insect communities. Turnover in pollinator communities was high and significantly related to the distance separating dune slacks.Overall, our results highlight the importance of large patches for sustaining both plant and pollinator communities. Additionally, enhancing connectivity has the potential to promote plant diversity and consequently benefit pollinator species. [ABSTRACT FROM AUTHOR]

In this study, centrifuge model tests were carried out to investigate the lateral response of single pile in coral sand foundation. The load–displacement relationships, pile deflections, bending moments, the changes in horizontal soil pressure, the predicted particle crushing behaviors, and p-y curves were compared and discussed in detail to study the influence of pile diameter and vertical load. Test results show that increasing diameter is the most direct and effective method to improve the horizontal bearing capacity of pile; the presence of vertical load would lead to an increase of bending moment and lateral displacement of the pile due to P-Δ effect and an improvement in soil resistance due to the vertical compression effect; the influence of particle breakage behavior of coral sand was not significant. In addition, the applicability of the existing p-y models for the coral sand foundation was systematically evaluated. According to the comprehensive analysis of the stress state of sand around pile, the evolution of soil resistance with depth was determined, which can be simulated by a power function. Based on the centrifuge test results, a modified p-y model for coral sand was proposed, and its rationality and applicability in predicting pile–soil responses were validated systematically. [ABSTRACT FROM AUTHOR]

The article explores the Spring Warrior civic-ceremonial center on Florida's Gulf Coast, which is one of the earliest centers of its kind in eastern North America. The site has recently been investigated, revealing evidence of village occupation, changes in subsistence, and a unique architectural feature using oyster shells for structural support. The findings highlight the significance of the Spring Warrior Complex in the ancient social landscape and ongoing research aims to nominate it for the National Register of Historic Places. The article provides insights into the origins and persistence of residential villages among hunter-gatherer-fishers in eastern North America, with unique local distinctions influenced by sociocultural, environmental, and climatic factors. [Extracted from the article]

In this study, the impacts to soil thermal properties during and after biocementation via microbially induced calcite precipitation (MICP) method on silty silica sand specimens with varying fines content (0%, 5%, and 15%) were investigated. Firstly, calcium conversion was measured after each pulse; then, the MICP-treated specimens were tested for cementation uniformity. The evolution of thermal conductivity of silty soils with the MICP treatment was assessed using a thermocouple probe. The results show that thermal conductivity of silty saturated sands increased by 17% for specimens treated to 9.7% CaCO3. The improvement in thermal conductivity was attributed to the formation of calcium carbonate bridges binding the soil grains together. The results suggested that the thermal conductivity of silty soil depends on water content, the number of treatment pulses, and the treatment uniformity through the soil specimen. Presence of fines content in the soil was found to play an important role in the distribution and uniformity of biocementation through the soil specimen. However, no statistically significant difference in the thermal conductivity values of MICP-treated specimens with different fines content was observed (p>0.05). The average calcium carbonate content ranged between 10.7% and 7.2% for the soils with 0% and 15% fines content, respectively. The findings of this research could be used to improve the efficiency of geothermal boreholes and other energy geostructures using MICP by improving thermal conductivity of dry and partially saturated soil. [ABSTRACT FROM AUTHOR]

The behavior of carbonate sand is different from that of siliceous sand in terms of high compressibility and crushability, specific particle shape, and physical properties. Thus, investigating the behavior of these soils is of great importance because of their prevalence in coastal areas. Nevertheless, a few studies have considered the presence of fines in the mixture with carbonate sand. The present study explores the influence of non-plastic fines on the undrained monotonic behavior of Bushehr carbonate sand. For this purpose, 30 undrained monotonic triaxial tests were performed on carbonate sand with silt ranges of 0% to 40% with two different void ratios. According to the results, the undrained shear strength of carbonate sand diminished with the addition of silt percentage up to 20%, and increased dramatically at 30% silt content. Also, the results of 40% silty sand revealed that this sample is stronger than samples with 10% and 20% silt content. By surveying the location of the phase transformation point in samples, it was observed that silt particles reduce the dilative phase. Also, confining pressure intensified the contractive phase while relative density had the opposite effect. The results showed that the effect of particle breakage is negligible in this study. [ABSTRACT FROM AUTHOR]

The Nikuradse roughness height for a river channel or, equivalently, the friction factor (f) or Manning's coefficient, are parameters required to calibrate hydrodynamic models used for flood risk management. In general, modeling hydraulic roughness includes the contributions of skin friction, related to sediment grain size, and bed-form roughness, related to bed-form geometry. Frequently, bed-form resistance is larger than the resistance due to skin friction. An empirical approach has been presented in the literature to estimating bed-form roughness, which is widely used for engineering purposes. This contribution presents an alternative physically based formulation for dune roughness estimation. Flow resistance generated by the bed form is assumed to arise from the drag force exerted by the bed, based on depth-averaged flow quantities. The new formulation agrees with existing experimental laboratory results and new field data from the Tercero (Ctalamochita) River, Córdoba, Argentina. [ABSTRACT FROM AUTHOR]

Amarasekara, K.; Perera, C.; Yatawara, M., and Jayasiri, H.B., 2024. Lesser-known species (Ipomoea imperati) from the Convolvulaceae family: First record from the Manalkaadu sand dunes of Jaffna, Sri Lanka. Journal of Coastal Research, 40(4), 803–808. Charlotte (North Carolina), ISSN 0749-0208. Coastal sand dunes are dynamic and fragile ecosystems found along some sandy shorelines. They are typically supported by a wide variety of specialized floral and faunal life. Coastal sand dunes are especially common in temperate coastal areas but are less abundant in tropical or subtropical coasts. A comprehensive study of flora in the Manalkaadu sand dune ecosystem was completed from August 2022 to May 2023, using 50-m × 5-m belt transects. The study area was divided into nine distinct locations for systematic sampling. Ipomoea imperati (Vahl) Griseb., a dicotyledonous flowering plant commonly known as fiddle-leaf morning-glory of the Convolvulaceae family, was recorded for the first time in the Manalkaadu sand dunes of the Northern Province in Sri Lanka during the study. Ipomoea imperati has smooth trailing stems that are covered with alternately arranged lanceolate, fleshy dark green leaves with a notched apex. Ipomoea imperati bloomed from September 2022 to March 2023 in the study area, and the funnel-shaped flowers were fused with white petals and yellow centers. In the area where it was discovered, the species withstood high substrate temperatures (about 29°C to 35°C), sand scouring, and moderate burial by accreted sand. Out of nine sampling locations, I. imperati was found in five locations. The plant density (two to six), plant percentage frequency (40% to 60%), Shannon Wiener diversity index (0.54 to 1.43), species evenness (0.50 to 0.90), and richness (2 to 5) were also analyzed. Thus, the density of I. imperati in five sampling locations was considered to be moderate, whereas the diversity was very low. It is designated as endangered in the National Red List 2020—Conservation Status of the Flora of Sri Lanka. [ABSTRACT FROM AUTHOR]