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Earthquake recurrence intervals, surface-rupture extents, and interactions between faults provide insight into how faults behave and are critical for seismic hazard mitigation and earthquake forecasting. Investigating the paleoseismology of spatially related faults can reveal strain distribution and whether faults rupture as a system or independently. Summer Lake basin, a graben in the northwestern Basin and Range with four active faults (three of which have prior paleoseismic investigations), provides an opportunity to investigate fault interactions. To expand the paleoseismic record, two trenches were excavated across the previously undocumented Thousand Springs fault, exposing a normal fault zone that offsets a sequence of deep- to shallow-water lake sediments, sand dunes containing reworked Mazama ash, and other Cascades-sourced tephra. Tephra units were correlated to known units by their physical characteristics, stratigraphic sequence, glass chemistry, and two new radiocarbon dates from the uppermost lake sediments. Using trench exposures, measured vertical separations through auguring, colluvial wedges, and extrapolated offsets based on a constant sedimentation rate, we identified at least five surface-rupturing earthquakes with a total offset of 3.4 + 2/-1 m in the past ~65 ka. The oldest event (EH5) occurred at 63.8 ± 1.5 ka, event horizon 4 at 36.2 ± 12.7 ka (which could be more than one event), and event horizon 3 at 24.6 ± 0.3 ka. Event horizon 2, a warping event at our site, is likely more than one event and occurred between 7.5 and 10 ka; and the most recent event (EH1+), most likely more than one event, occurred between 3.3 and 7.7 ka. Several events correlate, within error, with events on other faults in the Summer Lake basin, suggesting that (1) the faults generally rupture together as a system, (2) the most recent earthquake may have ruptured all faults in the region, and (3) fault rupture is influenced by the rapid regression of Lake Chewaucan (~13 ka). [ABSTRACT FROM AUTHOR]

Modern approaches with advanced technology can automate and expand the extent and resolution of biodiversity monitoring. We present the development of an innovative system for automated wildlife monitoring in a coastal Natura 2000 nature reserve of the Netherlands with 65 wireless 4G wildlife cameras which are deployed autonomously in the field with 12 V/2A solar panels, i.e. without the need to replace batteries or manually retrieve SD cards. The cameras transmit images automatically (through a mobile network) to a sensor portal, which contains a PostgreSQL database and functionalities for automated task scheduling and data management, allowing scientists and site managers via a web interface to view images and remotely monitor sensor performance (e.g. number of uploaded files, battery status and SD card storage of cameras). The camera trap sampling design combines a grid-based sampling stratified by major habitats with the camera placement along a traditional monitoring route, and with an experimental set-up inside and outside large herbivore exclosures. This provides opportunities for studying the distribution, habitat use, activity, phenology, population structure and community composition of wildlife species and allows comparison of traditional with novel monitoring approaches. Images are transferred via application programming interfaces to external services for automated species identification and long-term data storage. A deep learning model for species identification was tested and showed promising results for identifying focal species. Furthermore, a detailed cost analysis revealed that establishment costs of the automated system are higher but the annual operating costs much lower than those for traditional camera trapping, resulting in the automated system being >40 % more cost-efficient. The developed end-to-end data pipeline demonstrates that continuous monitoring with automated wildlife camera networks is feasible and cost-efficient, with multiple benefits for extending the current monitoring methods. The system can be applied in open habitats of other nature reserves with mobile network coverage.

In North‐West Europe and throughout the world, dune systems are increasingly stabilised by vegetation, due to both human intervention and changes in climate. Blowouts are erosional hollows produced by wind erosion in vegetated or semi‐vegetated dune systems. Where active blowouts are present in vegetated dunes, they provide a source of dynamism and sediment in an otherwise fixed environment. The transition from a fixed vegetated dune to an active blowout is poorly understood, however, and anthropogenic attempts to reactivate areas of bare sand in dunes are often unsuccessful. In this study, we measured topographic change at a monthly resolution in the deflation basins of one bowl and one trough blowout over a 23‐month period in Ainsdale Sand Dunes National Nature Reserve, North‐West England. Our results show that monthly surface change in the blowouts did not correlate strongly with the transport capacity of winds measured at a meteorological station 10 km south of the site. Precipitation was found to have a moderate negative correlation with all indices of surface change, that is, the more it rained the less the surface changed. Inter‐annual (23 months) patterns of topographic change in the bowl and trough blowouts were distinctly different. In the deflation basin of the bowl blowout erosion predominantly took place on the erosional walls facing into the prevailing winds, while minimal change occurred on the erosional walls facing away from the prevailing wind direction. This produced a moderate negative correlation between surface change and slope, that is, the steeper the slope, the more erosion occurred. In the trough blowout, erosion took place in the centre of the deflation basin and minimal change was measured on the easternmost erosional wall, which faced the prevailing winds. Patterns of monthly topographic change were highly variable and demonstrated that changes in the direction of above‐threshold winds can cause blowout walls and floors to 'flip' from erosional to depositional surfaces. These findings highlight the variability and complexity of surface change in blowouts and demonstrate that patterns vary because of landform morphology and climatic conditions. [ABSTRACT FROM AUTHOR]

The Deliblato (Banat) Sand Sea, which is one of the largest areas of аeolian sand in Europe, is located near the Iron Gate, which marks the crossing of the Danube River through the biggest gorge of this river. Here, Danubian alluvium has served as the sand source for the Banat Sand Sea, which was formed primarily through southeasterly (Košava) winds. Utilizing a multi-proxy approach, the objective of this study is to gain a better understanding of the environmental dynamics of the Banat Sand Sea. To achieve this goal, we conducted an analysis of an archive representing an approximately 20-m-thick dune formation on the northern edge of this dune field. Using optically stimulated luminescence (OSL) dating, we calculated aeolian sedimentation rates and dune ages. Sand was deposited here approximately between 17 ka and 13 ka. Magnetic susceptibility, grain size, and colorimetric analyses were interpreted in terms of local paleoenvironmental conditions. Calculated sedimentation rates (SR) indicate intensive aeolian deposition during the study period that range from 483 cm/ka to 502 cm/ka. We compared our data with regional and other European archives, as well as with climatic variations recorded in the Greenland ice core North Greenland Ice Core Project (NGRIP). [ABSTRACT FROM AUTHOR]

• Automating wildlife monitoring with wireless 4G cameras and end-to-end data streams. • Remote monitoring of sensor performance, API handling and automated task management. • Deep learning for automated identification of focal species and human detection. • Total cost saving of >40 % through automation, AI and less regular site visits. • Enabling technologies allow scaling-up of a cost-efficient biodiversity monitoring. Modern approaches with advanced technology can automate and expand the extent and resolution of biodiversity monitoring. We present the development of an innovative system for automated wildlife monitoring in a coastal Natura 2000 nature reserve of the Netherlands with 65 wireless 4G wildlife cameras which are deployed autonomously in the field with 12 V/2A solar panels, i.e. without the need to replace batteries or manually retrieve SD cards. The cameras transmit images automatically (through a mobile network) to a sensor portal, which contains a PostgreSQL database and functionalities for automated task scheduling and data management, allowing scientists and site managers via a web interface to view images and remotely monitor sensor performance (e.g. number of uploaded files, battery status and SD card storage of cameras). The camera trap sampling design combines a grid-based sampling stratified by major habitats with the camera placement along a traditional monitoring route, and with an experimental set-up inside and outside large herbivore exclosures. This provides opportunities for studying the distribution, habitat use, activity, phenology, population structure and community composition of wildlife species and allows comparison of traditional with novel monitoring approaches. Images are transferred via application programming interfaces to external services for automated species identification and long-term data storage. A deep learning model for species identification was tested and showed promising results for identifying focal species. Furthermore, a detailed cost analysis revealed that establishment costs of the automated system are higher but the annual operating costs much lower than those for traditional camera trapping, resulting in the automated system being >40 % more cost-efficient. The developed end-to-end data pipeline demonstrates that continuous monitoring with automated wildlife camera networks is feasible and cost-efficient, with multiple benefits for extending the current monitoring methods. The system can be applied in open habitats of other nature reserves with mobile network coverage. [ABSTRACT FROM AUTHOR]

This article explores the potential for a broader, more integrated treatment of the long-term development of Latvia's coastal landscape, seeking avenues for conveying its dynamism. Various transformational processes are considered, with a particular focus on dune migration – formerly a major issue in Latvia but nowadays essentially resolved and forgotten. Relief features of the sandy, forested areas, as well as old pine trees, serve as cues to temporality in the present terrain, while historical and folkloric sources provide insights into past perceptions of the landscape and the experiences and imaginings of landscape change. [ABSTRACT FROM AUTHOR]

The article presents the features of the geomorphological landscape dominated by sand covers and dunes within the inactive middle Warta River valley. Detailed geological and geomorphological mapping, sedimentological analysis and age determinations using 14C and OSL methods allowed their formation to be placed in the late Weichselian/early Holocene and the late Holocene. It was found that the nature of aeolian processes is the result of local aerodynamic conditions, the presence of alluvia and fluvioglacial deposits, and substrate moisture. [ABSTRACT FROM AUTHOR]

Copyright of South African Journal of Cultural History is the property of South African Society for Cultural History and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: Arbuscular mycorrhizal fungi (AMF) are ubiquitous plant root symbionts, which can house two endobacteria: Ca. Moeniiplasma glomeromycotorum (CaMg) and Ca. Glomeribacter gigasporarum (CaGg). However, little is known about their distribution and population structure in natural AMF populations and whether AMF can harbour other endobacteria.We isolated AMF from two environments and conducted detailed analyses of endobacterial communities associated with surface‐sterilised AMF spores.Consistent with the previous reports, we found that CaMg were extremely abundant (80%) and CaGg were extremely rare (2%) in both environments. Unexpectedly, we discovered an additional and previously unknown level of bacterial diversity within AMF spores, which extended beyond the known endosymbionts, with bacteria belonging to 10 other phyla detected across our spore data set. Detailed analysis revealed that: CaGg were not limited in distribution to the Gigasporaceae family of AMF, as previously thought; CaMg population structure was driven by AMF host genotype; and a significant inverse correlation existed between the diversity of CaMg and diversity of all other endobacteria.Based on these data, we generate novel testable hypotheses regarding the function of CaMg in AMF biology by proposing that they might act as conditional mutualists of AMF. [ABSTRACT FROM AUTHOR]

The current paper deals with the navigable section of the Volga River tailwater of the Nizhny Novgorod Hydropower Plant. To ensure navigation in this area, the existing navigation structures are being reconstructed and an additional chamber of the Gorodets Navigation Lock is to be constructed, and an extended navigable channel in the Volga River is to be created. To assess the impact of the planned measures on hydrological and riverbed regimes, the hydromorphological situation has been analyzed, and the flow parameters and the water level regime in the tailwater pool of the hydro system have been studied. An analysis of the changes in the riverbed along the design channel path was done and the kinematics of the flow and sediment transport parameters were studied under conditions of unsteady water movement resulting from the daily regulation of the river flow. Numerical experiments have revealed the peculiarities of river sediment movement under conditions of unsteady water movement, and recommendations for modeling river bed deformation under such conditions have been developed. It was found that with daily and weekly regulation of river, discharge bedload transport becomes more active at the moment when a wave of daily release from the upper reaches of the hydrosystem passes through. The basic characteristics of bedload transport, i.e., dune velocity and bedload rate, increase in comparison with a steady water flow. Under the conditions of unsteady water movement due to the daily regulation of the river flow, there are no strong changes in the size of the bottom dunes, while their velocity, and, consequently, the bedload rate increases significantly during periods when the wave of daily water releases from upstream passes. The results obtained indicate that for hydraulic calculations of the characteristics of water movement and sediment transport, it is necessary to use data from hourly observations of flow rates and water levels. It was found that during the passage of release waves under daily flow regulation, there are short periods of increase in Froude number values. Similarly, the bedload rate increased during these periods compared to the average daily values. The result of this comparison ultimately led to the recommendation that daily flow regulation should be abandoned in order to reduce the intensity of bedload transport rate and channel erosion in the tailwater of the hydrosystem. [ABSTRACT FROM AUTHOR]

Copyright of Arid Land Geography is the property of Chinese Academy of Sciences, Xinjiang Institute of Ecology & Geography and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dunes are important for bedload transport in almost all large river systems and exert an important control flow resistance. Investigating dunes is fundamental for simulating discharge, sediment transport, and flood routing. However, the spatiotemporal dynamics of dunes and flow resistance remain poorly understood in large alluvial river systems mainly due to the lack of high‐resolution data. Here we analyzed in‐field observed data on annual profiles of 450 cross‐sections, river bathymetry, discharge, water levels, and sediment in the Middle Yangtze River, and found that dunes developed and flow resistance increased (+10%) in the post‐Three Gorges Dam period. We ascertain that the development of dunes plays the dominant role in augmenting flow resistance, as evidenced by roughness height change (+29%) using a modified Van Rijn method. Ultimately, dune development was incorporated into a hydrogeomorphic numerical model of the Yangtze River to improve flow resistance quantification, and thus, the water level simulation. Our findings highlight the potential increase in flow resistance in response to upstream damming in large rivers and have important implications for flood management and riverine ecology. Key Points: Random wave analysis is utilized to evaluate dune characteristics and calculate flow resistanceAn amplificated flow resistance after upstream damming, declining with downstream distanceThe development of large dunes accompanied by riverbed grain coarsening jointly increases flow resistance [ABSTRACT FROM AUTHOR]

Dunes are ubiquitous features in alluvial channels, serve as major agents of sediment transport and contribute significantly to flow resistance. Research in the past decade has illustrated the complexity of dune geometry and widespread occurrence of dunes that have a low leeside angle. However, there is a debate concerning the occurrence of such dunes and their formative processes. This paper seeks to further our understanding of low‐angle dunes by utilizing data from a robust set of shallow flow laboratory experiments detailing equilibrium bedform morphology across a range of sediment transport conditions. Analysis of bedform morphology demonstrates that dunes with low‐angle leesides are generated in shallow laboratory flows and are not restricted to deep rivers. Of the possible processes that have been proposed to explain the formation of low‐angle dunes, this finding unequivocally shows that liquefied leeside avalanches, which rely on deep flows for their generation, are not a controlling mechanism. In addition, dunes formed under suspension‐dominated conditions possess lower leeside angles compared with those formed under bedload‐dominated conditions. However, where bedload transport dominates and sediment suspension is likely of lesser importance, low‐angle dunes are still present, and preliminary analysis shows that bedform superimposition can result in lowering of the dune leeside angle. Low and intermediate angle dunes formed under these various conditions also have a lower potential for large‐scale, permanent, leeside flow separation compared with angle‐of‐repose dunes, confirming the need to account for these differences in predictions of flow resistance associated with dune form roughness. Plain Language Summary: Dunes that form on a riverbed have often been thought to possess high‐angle sloping downstream faces. However, in deep rivers, it has been shown that dunes overwhelmingly have shallower sloping, low‐angle, downstream faces—forming low‐angle dunes. This finding has raised questions regarding the occurrence of low‐angle dunes within different depth rivers and the processes controlling their formation. In this paper, we analyze data from shallow‐depth laboratory experiments that detail 3D maps of dunes in order to examine their shape and help understand the processes that lead to their formation. We show that liquefied leeside avalanches are not a control because low‐angle dunes can form in shallow flows where such avalanches cannot be generated. Instead, we find that low and intermediate angle dunes are common when sediment transport is dominated by particles in suspension rather than in bedload transport, suggesting that sediment suspension is vital to their generation. However, when sediment transport is dominated by particles rolling along the bed in bedload transport, smaller superimposed bedforms can lower the leeside angle of the dune over which they are climbing. These findings suggest a balance between sediment suspension and bedform superimposition as mechanisms controlling the formation of low and intermediate angle dunes. Such characterization of dunes is important for predicting flow and flood height within river channels. Key Points: Low, intermediate, and high angle dunes form in shallow laboratory flowsSediment suspension and bedform superimposition are the key mechanisms controlling the formation of low‐angle dunesLiquefied leeside avalanches do not play a role in the formation of low‐angle dunes [ABSTRACT FROM AUTHOR]

Connectivity is a species- and landscape-specific measure that is key to species conservation in fragmented landscapes. However, information on connectivity is often lacking, especially for insects which are known to be severely declining. Patterns of gene flow constitute an indirect measure of functional landscape connectivity. We studied the population genetic structure of the rare digger wasp Bembix rostrata in coastal and inland regions in and near Belgium. The species is restricted to sandy pioneer vegetations for nesting and is well known for its philopatry as it does not easily colonize vacant habitat. It has markedly declined in the last century, especially in the inland region where open sand habitat has decreased in area and became highly fragmented. To assess within and between region connectivity, we used mating system independent population genetic methods suitable for haplodiploid species. We found more pronounced genetic structure in the small and isolated inland populations as compared to the well-connected coastal region. We also found a pattern of asymmetrical gene flow from coast to inland, including a few rare dispersal distances of potentially up to 200 to 300 km, based on assignment tests. We point to demography, wind and difference in dispersal capacities as possible underlying factors that can explain the discrepancy in connectivity and asymmetrical gene flow between the different regions. Overall, gene flow between existing populations appeared not highly restricted, especially at the coast. Therefore, to improve the conservation status of B. rostrata, the primary focus should be to preserve and create sufficient habitat for this species to increase the number and quality of (meta) populations, rather than focusing on landscape connectivity itself. [ABSTRACT FROM AUTHOR]

Harsh environmental conditions form habitats colonized by specialized primary microbial colonizers, e.g., biological soil crusts (biocrusts). These cryptogamic communities are well studied in drylands but much less in temperate coastal dunes, where they play a crucial role in ecological functions. Following two dune chronosequences, this study highlights the successional development of the biocrust's community composition on the Baltic Sea coast. A vegetation survey, followed by morphological species determination, was conducted. Sediment/soil cores of the different dune types were analyzed to uncover the potential impacts of the biocrust community on initial soil formation processes, with special emphasis on biogeochemical phosphorous (P) transformations. Biocrust succession was characterized by a dune type-specific community composition, shifting from thinner algae-dominated biocrusts in dynamic dunes to more stable moss-dominated biocrusts in mature dunes. The change in the biocrust community structure was accompanied by an increase in Chl a, water, and organic matter content. In total, 25 algal and cyanobacterial species, 16 mosses, and 26 lichens across all sampling sites were determined. The pedological characterization of these cores elucidated initial processes of soil genesis, such as decalcification, acidification, and the accumulation of organic matter with dune and biocrust development. Furthermore, the chemistry of iron (Fe)- containing compounds such as the Fedithionite/Fetotal ratios confirmed mineral weathering and the beginning of soil profile development. The biocrusts accumulated P over time, while the P content in the underlying sediment did not change. That implies that biocrusts take up P from the geological parent material in the dunes, thereby accumulating available P in the ecosystem, which gets transferred into subsoil horizons through leaching or redeposition. The relative proportion of the bioavailable P pool (56% to 74% of Pt) increased with dune succession. That happened at the expense of more stable bound P, which was transformed into labile P. Thus, the level of plant available P along the dune chronosequences increased due to the microbial activity of the biocrust organisms. It can be concluded that biocrusts of temperate coastal dunes play a crucial role in maintaining their habitat by accumulating nutrients and organic matter, supporting soil development and subsequent vegetation. [ABSTRACT FROM AUTHOR]

This article provides a synthesis of the virtual Coastal Dunes for Resilience Workshop held on December 8th and 9th, 2021. In an effort to foster knowledge-sharing across these sites and disseminate information and lessons learned, the California Dune Science Network hosted the Workshop that featured recent dune research, information about nature-based dune and resilience projects, and collaborative learning opportunities at California's pilot project and natural dune sites. It also engaged diverse perspectives on coastal resource stewardship, public access, and culturally inclusive climate adaptation approaches and how these play a role in the success of coastal dune resilience efforts. The Coastal Dunes for Resiliency Workshop provided an initial opportunity for ideas and strategies to be shared amongst the many practitioners working in the coastal resilience space. The workshop highlighted common challenges, needs, and four emerging themes for implementing coastal dunes for resilience in California: (1) there is no one-size-fits-all approach to designing dunes for resilience, (2) defining resilience goals and expectations are key to selecting an effective dunes approach, (3) importance of socio-cultural engagement and perceptions in dune project success, and (4) evaluating project and shoreline resilience is key to optimizing project designs and developing best practices.These initial recommendations will allow for further conversations on how to evaluate strategies and move forward in a more unified and efficient way to meet the needs of our coastal communities and ecosystems. The Network will continue to build its base of knowledge and contribute to best practices that make sense for the California landscape. Further workshops should dig into the details of how to effectively design dune resilience projects and monitoring and management strategies, while meeting the changing and unique needs of beach users and coastal community members and infrastructure impacted by sea-level rise.

Depositional and erosional bedforms can be used to reconstruct sedimentary processes and aid palaeoenvironmental interpretations. Using exhumed deep-marine strata in the Eocene Aínsa Basin, Spain, we document a 3-dimensional package of dunes, a rarely identified bedform in deep-marine environments. Our analysis shows that the dunes have curvilinear crests in planform, with smaller superimposed oblique dunes and ripples across the stoss sides. Beds containing these dunes have two main internal divisions: a lower inversely-graded (fine-to-coarse sandstone) and predominantly structureless division, and an upper coarse-grained sandstone division with well-developed cross-stratification, which is scoured and mantled with mudclasts and coarse-grains on the stoss-side. The rugose remnant relief of the bedforms controls the location of subsequent bedforms. Following recently reported direct measurements of natural turbidity currents, we interpret the basal division as recording deposition from the dense basal head of a high-velocity turbidity current, followed by the development of dunes beneath the more sustained but relatively high-velocity and unsteady flow body that reworked the initial sandy deposit into downstream migrating dunes and scours. These dune-forming beds have been identified in different deep-water environments in the Aínsa Basin stratigraphy, including channel overbank and channel mouth settings and scour-fills. These locations suggest that the dunes were intimately tied to high-velocity flows that bypassed through channel axes before expanding and depositing in less confined channel overbank or channel mouth settings. Preservation of these dunes in the Aínsa Basin was likely enhanced by tectonically-forced lateral migration of channels, which prevented cannibalisation of bypass-dominated zones, in combination with high aggradation rates due to confinement. Where identified these dune-like bedforms are considered diagnostic of substantial sediment bypass downslope to deep-water basins. This article has a related Corrigendum

Harsh environmental conditions form habitats colonized by specialized primary microbial colonizers, e.g., biological soil crusts (biocrusts). These cryptogamic communities are well studied in drylands but much less in temperate coastal dunes, where they play a crucial role in ecological functions. Following two dune chronosequences, this study highlights the successional development of the biocrust’s community composition on the Baltic Sea coast. A vegetation survey, followed by morphological species determination, was conducted. Sediment/soil cores of the different dune types were analyzed to uncover the potential impacts of the biocrust community on initial soil formation processes, with special emphasis on biogeochemical phosphorous (P) transformations. Biocrust succession was characterized by a dune type-specific community composition, shifting from thinner algae-dominated biocrusts in dynamic dunes to more stable moss-dominated biocrusts in mature dunes. The change in the biocrust community structure was accompanied by an increase in Chl a, water, and organic matter content. In total, 25 algal and cyanobacterial species, 16 mosses, and 26 lichens across all sampling sites were determined. The pedological characterization of these cores elucidated initial processes of soil genesis, such as decalcification, acidification, and the accumulation of organic matter with dune and biocrust development. Furthermore, the chemistry of iron (Fe)-containing compounds such as the Fedithionite/Fetotal ratios confirmed mineral weathering and the beginning of soil profile development. The biocrusts accumulated P over time, while the P content in the underlying sediment did not change. That implies that biocrusts take up P from the geological parent material in the dunes, thereby accumulating available P in the ecosystem, which gets transferred into subsoil horizons through leaching or redeposition. The relative proportion of the bioavailable P pool (56% to 74% of Pt) increased with dune succession. That happened at the expense of more stable bound P, which was transformed into labile P. Thus, the level of plant available P along the dune chronosequences increased due to the microbial activity of the biocrust organisms. It can be concluded that biocrusts of temperate coastal dunes play a crucial role in maintaining their habitat by accumulating nutrients and organic matter, supporting soil development and subsequent vegetation.

São Luís Island in Maranhão State, Brazil, has a vegetational mosaic where sandbanks with shrubs, small dunes, and mangroves are common. Due to its geography, the urbanization process in this area tends to form agglomerations that suffocate small rivers and streams. Based on a floristic survey of the family Malpighiaceae, we discuss the importance of taxonomic knowledge for the preservation of the flora of São Luís Island. We list 18 species of Malpighiaceae that occur in the area. Among them, only four have herbarium collections from the 21st century. Byrsonima intermedia and Heteropterys mathewsiana are new records for Maranhão State and Bunchosia apiculata is a new record for São Luís Island. Although they have not been formally assessed, most species are under threat, especially from disorderly urban growth and the unregulated discard of waste. Maintaining natural habitats and controlling threats might reveal relevant new findings about the diversity of Maranhão and contribute significantly to the preservation of the biodiversity on São Luís Island. [ABSTRACT FROM AUTHOR]

In Australia as elsewhere in the world, coastal archaeological sites are increasingly threatened by rising seas and changing storm patterns, along with encroaching human activities. Understanding the geomorphological context is key to understanding the positioning of archaeological deposits in or on coastal landforms, their vulnerability to erosion and their resilience and capacity for longer-term management and preservation. Here we review the dynamics of beach-barrier systems to contextualise the potential of archaeological deposits to survive erosional processes, especially those associated with current and anticipated impacts of climate change. In doing so, we outline a practical logic for zoning coastal landforms and processes by their proclivity to either erode or preserve archaeological deposits, to assist in the planning of management agendas. It is the sediment budgets and how they change in relation to variation in sea level that fundamentally determine the potential preservation of archaeological deposits in coastal beach-barrier environments. We advocate close transdisciplinary collaboration between archaeology, geomorphology and site managers (i.e. Traditional Owners and land-and-sea management agencies) to better understand the wider landscape dynamics of coastal archaeological sites and landscapes. [ABSTRACT FROM AUTHOR]

The paleopedological record documented in aeolian dunes of the eastern European Sand Belt comprises predominantly Arenosols and only occasionally well-developed Podzols. There are several Late Pleistocene pedostratigraphic marker horizons of varied soil types designated in the European dune and loess deposits, but none falls within the range of the Holocene. Buried Podzol occurrences found recently in 10 inland dune sites dispersed throughout Central and Eastern Poland share similar pedological properties, geomorphological setting, and age in the 5th–15th century AD range of the historical Middle Ages. Therefore, they meet the criteria for distinction as a pedostratigraphic marker under the name Grębociny soil, after a locality with the most advanced podzolization of the paleosol dated to the High Middle Ages (1000–1300 AD). Preservation of the soils was enabled by burial during anthropogenically induced dune remobilization. At least some of the investigated dunes were used as pasture during soil development, as evidenced by tetrapod hoofprints recorded in and above the buried Podzols. Prevalent podzolization during the Middle Ages, in contrast to preceding and later times, could be facilitated by not only an impact of agriculture and forestry, but also relative warmth and humidity of the Medieval Climatic Optimum (ca. 900–1400 AD). [ABSTRACT FROM AUTHOR]

Burrow excavation by mammals generates heterogeneity within landscapes. Globally, these disturbances are known to provide significant ecosystem benefits. Most investigations of native Australian burrowing mammal disturbances has focused on the role of burrows in landscape function and interspecific thermal refugia. Herein, we present a novel observation of the fossorial skink Lerista bougainvillii utilizing burrow mounds of the common wombat (Vombatus ursinus) for possible thermoregulatory gains. In the early morning, when thermoregulatory opportunities were limited, L. bougainvillii were detected in mounds that appeared hotter than adjoining vegetation. These observations suggest that in densely vegetated habitats thermal heterogeneity caused by mammal burrows may offer important thermoregulatory opportunities for fossorial species with limited climbing capacity. [ABSTRACT FROM AUTHOR]

Background: The present research aims to investigate the relationship between the phenomenon of desertification of agricultural lands and the expansion of the phenomenon of dunes in Iraqi Mesopotamia (central and southern Iraq), the phenomenon of global climate change, and the regional policies of the upstream countries neighboring Iraq. Method: The study uses, a monitoring process carried out using the data of satellite images of the Landsat series, for the period from 1984 to 2022, by ArcGIS program, with the tool of supervised classification. Results: Obviously, the danger of climate change and its effects on Iraq is shown in the results of this study, which showed that the fertile agricultural lands that were deserted constituted about 45% of the total lands until July 2022, including (16.67% of the total region) dunes or heavily decertified lands. The percentage of cultivated agricultural lands has deteriorated to 42%, a very serious decline compared to 1998 when the rate was more than 80%. Moreover, the most dangerous environmental situation right now is represented by the loss of more than half of its water bodies, as it currently (2022) constitutes only 12.47% of the study area, while it represented 26.9% of the study area in 1984. Conclusion: Based on the study results, we find out the annual precipitation rates are the climatic factor strongly affecting, the decline or expansion of the phenomenon of dunes, besides the neighboring country policies (Türkiye and Iran). [ABSTRACT FROM AUTHOR]

The movement of active dunes is tightly linked to climatic conditions (e.g., wind regime, temperature and precipitation) as well as human influence (e.g., grazing, dune fixation and greening). Dune migration rates can be studied to draw conclusions of changing wind conditions over time. The Gonghe Basin (GB), located on the north‐eastern Tibetan Plateau (TP), offers a good testing ground for these assumptions. The intramontane basin is highly influenced by two major wind regimes: the mid‐latitude Westerlies and the East Asian summer monsoon. To investigate environmental changes, this study combines optical remote sensing techniques with climatic datasets. High‐resolution satellite images of the last five decades, such as CORONA KH‐4B, are used to map dunes and calculate their respective migration rates. Further, height information was extracted as well. Climatic changes from the ERA‐5 reanalysis dataset and normalized difference vegetation index (NDVI) values were processed alongside. Relating the dunes' surface processes to climate model data shows an accordance between slowing migration, expanding vegetation and a decrease in sand drift potential. From 1968 to present time, an average dune migration rate of 7.3 m a−1 was extracted from the satellite images, with an overall reduction of −1.81 m a−1. The resultant drift potential (RDP) values for the GB are calculated to be below 10 m3 s−3 with a spatial decrease, following a direction from the NW to the SE, fitting well with a corresponding decrease in the migration rates. Our results indicate a good agreement between the development of aeolian landforms and the ERA‐5 climate reanalysis model data, even in a high‐altitude setting with complex topography, which is known to influence such datasets. [ABSTRACT FROM AUTHOR]

Beach and sun tourism in the Colombian Caribbean is an extremely important activity that leads to social practices that generate recreational and economic activities directly impacting the environment. The research focuses on assessing the sensitivity to the loss of beaches as tourist resources in four locations within the Colombian Caribbean (Santa Verónica, Salinas del Rey, Bocatocino, and Las Arenas). The sensitivity indicator was developed using GIS to process variables such as the width of the usable beach, the presence of dunes, and rates of coastal erosion spanning from 2003 to 2019. Additionally, anthropic occupation was examined through satellite images. The results allowed for identifying vulnerability indices and recognizing the critical role of dunes in beach preservation. The study revealed that the analyzed beaches exhibited varying degrees of sensitivity. Notably, historical erosion rates and dunes were the most influential variables affecting sensitivity. In conclusion, understanding the sensitivity state concerning the loss of beach areas as tourist resources helps delineate stable sectors and those more susceptible to erosion processes. This knowledge proves invaluable in prioritizing the design and implementation of protective measures in areas requiring urgent attention. [ABSTRACT FROM AUTHOR]

The Samalayuca Dunes (SMD) (Médanos de Samalayuca), Chihuahua, México, are one of México's largest and least studied dune fields, now managed as a Protected Area for their ecological characteristics. We present a morphometric characterization of the dune field based on remote sensing and field studies, to advance under standing of its physical environment. SMD's generally-fine sands originate from shoreline deposits of Paleolake Palomas, transported eastward (downwind) along an aeolian corridor, accumulating primarily as echo dunes upwind of the sierras of Samalayuca and Presidio. A complex wind regime, with northerly and southerly winds complementing regionally-prevailing southwesterlies, modified by topographic effects, shapes the SMD's morphology. The sand sea covers ~139.7 km2, with ~113.8 km2 in the main eastern body and ~25.9 km2 in a northwester n subfield. We describe six major dune for ms: north to south straight-crested dunes, east to west straight-crested dunes, star dunes, vegetated parabolic dunes, relict transverse dunes, and "megastar" (draa) dunes. Mean interdune centroid spacing is 76.5 m. The active dunes, previously described as an "aklé" pattern, are predominantly straight-crested dune sets oriented near-perpendicular to each other with general north-south and east-west crest orientations, 4-5 m high, spaced ~67 m apart for north-south trending crests and ~53 m for east-west trending crests, representing a nearly perpendicular interference pattern in some locations. The active dunes are superimposed in a compound and complex arrangement on relict remnants of much larger north-northwest trending transverse dune ridges fanning out from south to north-northwest, spaced approximately ~1 km apart and ~50 m high. The easternmost dune ridge contains an active set of at least 15 active megastar and reversing dunes up to 120 m tall, increasing in size and complexity from south to north. As a protected area with historical and ecological value, additional geologic investigations should be performed at the SMD, to help conserve this remarkable geologic feature. [ABSTRACT FROM AUTHOR]

Coastal dunes along Lake Michigan's eastern shoreline are a unique system comprising perhaps the largest complex of freshwater coastal dunes in the world. Here, we examine the blowouts in this region and determine how they have evolved since the 1930s. We conducted a spatiotemporal analysis of 435 blowouts by comparing repeat aerial images of the coast beginning in 1938. Using an unsupervised machine learning classification known as iso-clustering, we mapped blowout morphologies at three timestamps: 1938, 1986-1988, and 2018.We then compared the blowout geographies through a technique known as a spatial-temporal analysis of moving polygons (STAMP) model, which allowed us to analyze how each blowout changed in time and space. Results show blowouts have contracted ~37% in size since 1938, mostly at the expense of vegetation, with many fragmenting. These findings comport with other regional and global studies detailing a trend in coastal dune stabilization from vegetation and suggest that an increase in precipitation or other environment drivers could be responsible. Moreover, we detected no new blowouts since 1938 along the ~500 km shoreline or on any of the Lake Michigan islands. This suggests blowouts here are artifacts of premodern conditions, perhaps the result of prior stormier or drier eras. [ABSTRACT FROM AUTHOR]

Ubiquitous Holocene dune systems are associated with major west-to-east flowing rivers across the Southern Great Plains (SGP), USA. Critical questions remain as to whether aeolian activity reflects multiple environmental signatures, including increased sand supply from riverine sources. This research focused on the western Red River where geomorphic mapping revealed three terrace levels up to 16 m, buried partially by up to 10 m of aeolian sediments. Pedosedimentary facies analyses of sections and Geoprobe cores extracted from terraces and close-interval optically stimulated luminescence dating of quartz grains revealed two periods of fluvial aggradation at ca. 80 ka to ~5 to 8m above the Red River forming the Vernon terrace, and at 30 to 13 ka to ~20-15 m, the highest identified Childress terrace. Net degradation of 20 m also occurred between 13 and 7 ka to 4 m below the current channel, reflecting regional fall in the groundwater level. The latest aggradation event, which built the lowest Luna terrace at ~2 m, ended 1.5 to 0.7 ka and was partially buried by fluvial-sourced dunes in the sixteenth and seventeenth centuries. This recent phase of aeolian deposition coincides with a comparatively wet period in the central United States during the Little Ice Age, rather than with regional drying. [ABSTRACT FROM AUTHOR]

The timeframes of Holocene anthropogenic dune remobilization in Central Europe remain less studied compared to those of Late Glacial climatically controlled dune formation. The present contribution aims to reinforce existing knowledge on the chronology of Late Glacial–Holocene dune activity and stability, as well as to reveal the scale of human impact on dune remobilization. Accelerator mass spectrometry radiocarbon (AMS 14C) dating and calibration of the results are reported from paleosol horizons buried in inland dune deposits that occur in Central and Eastern Poland. Twenty-three new dates are based on charcoal samples collected at 13 sites. From each of the investigated sites, at least one AD date is obtained, indicating that buried paleosols of such young age are far more widespread in Polish dunes than reflected in previous studies. The widespread preservation of these paleosols under cover of aeolian sand reflects the extent of the anthropogenic dune formation phase that peaked during the Medieval and Early Modern periods. [ABSTRACT FROM AUTHOR]

A Silurian shift in fluvial stratigraphic architecture, coincident with the appearance of terrestrial vegetation in the fossil record, is traditionally cited as evidence for exclusively shallow, braided planforms in pre‐vegetation rivers. While recent recognition of deep, single‐thread channels in pre‐Silurian strata challenge this paradigm, it is unclear how these rivers maintained stable banks. Here, we reconstruct paleohydraulics and channel planform from fluvial cross‐strata of the 1.2 Ga Stoer Group. These deposits are consistent with deep (4–7 m), low‐sloping rivers (2.7 × 10−4 to 4.5 × 10−5), similar in morphometry to modern single‐thread rivers. We show that reconstructed bank shear stresses approximate the cohesion provided by sand‐mud mixtures with 30%–45% mud—consistent with Stoer floodplain facies composition. These results indicate that sediment cohesion from mud alone could have fostered deep, single‐thread, pre‐vegetation rivers. We suggest that the Silurian stratigraphic shift could mark a kinematic change in channel migration rate rather than a diversification of planform. Plain Language Summary: The earliest appearance of rooted plant fossils coincides with widespread evidence of meandering rivers in the geologic record. This correlation has led researchers to suggest that meandering rivers only existed on our planet since terrestrial plants colonized the continents, and that pre‐vegetation rivers were predominantly characterized by shallow and multi‐thread channels. While there is growing evidence of deep, single‐thread rivers predating the rise of land plants, it is currently unclear how these rivers maintained stable banks. Here, we combine observations of 1.2‐billion‐year‐old river sediments in NW Scotland with mechanistic theories of river dune formation to constrain the geometry of pre‐vegetation rivers. We show that our field observations are consistent with deposition by deep, low‐sloping, and single‐thread rivers, whose reconstructed geometry is similar to modern‐day meandering, rather than braided, rivers. We also demonstrate that the mud fraction of the floodplain sediment could have provided sufficient cohesion to resist erosional forces in deep, low‐sloping rivers. Together, our results indicate that single‐thread rivers could have been prevalent before the rise of land plants, and that mud can provide sufficient bank strength for the development of deep rivers. Key Points: Quantitative paleohydraulic tools indicate that deep, low‐sloping rivers were characteristic of 1.2 Ga Stoer GroupPaleohydraulic data plot in the single‐thread river planform regime in mechanistic frameworks for discriminating channel planformField observations and theory indicate that the mud in bank sediments can provide sufficient cohesion to maintain deep flows [ABSTRACT FROM AUTHOR]

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Understanding the dynamics of beach–dune systems is crucial for effective coastal management. The cellular automata model DuBeVeg provides a powerful tool for simulating and understanding the bio-geomorphological evolution of these systems, capturing key interactions of aeolian, hydro-, and vegetation dynamics in a simplified manner. In this study, we present an alternative representation of the aeolian transport component in DuBeVeg, aiming to better capture the saltation transport mode that prevails on beaches. This new representation is compared with the original aeolian transport representation in DuBeVeg, which is inspired by ripple migration. For three beach width scenarios, we considered the effects of the different aeolian transport representations on the predicted foredune morphology after 50 years, as well as the spatio-temporal evolution of the beach–dune system leading to that morphologic state. The saltation transport representation resulted in a more realistic simulation of the seaward expansion of the foredune compared with the original representation, particularly in scenarios with wide and prograding beaches. The new representation also more accurately captured the amplitude of aeolian bedforms emerging across the beach. These findings highlight the importance of selecting the representative transport mode when simulating the transient bio-geomorphological evolution of beach–dune systems. [ABSTRACT FROM AUTHOR]

Sand grains are ubiquitous in the Earth’s system, and are found in different environmental settings globally, but sand itself as a physical object has multiple conflicting meanings with respect to both its agglomeration into landforms such as sand dunes and beaches, and how sand and its dynamics have cultural significance and meaning. This study takes a transdisciplinary approach towards examining the multiple meanings of sand, focusing on sand as a spatiotemporal pheneomenon that exists in different contexts within the Earth system. The nature and spatiotemporalities of sand are framed in this study through the concepts of presence, absence and transience, which are key interpretive approaches that lie at the interface of how the physical and phenomenological worlds interact with each other. This is a new and innovative approach to understanding people–environment relationships. These concepts are then discussed using the examples of the dynamics of and values ascribed to desert dune and sandy beach landscapes, drawn from locations globally. These examples show that the dynamic geomorphic changes taking place in sand landscapes (sandscapes) by erosion and deposition (determining the presence and absence of sand in such landscapes) pose challenges for the ways in which people make sense of, locate, interact with and value these landscapes. This uncertainty that arises from constant change (the transience of sandscapes) highlights the multiple meanings that sandscapes can hold, and this represents the comforting yet also unsettling nature of sand, as a vivid symbol of human–Earth relationships.

Intense aeolian processes in arid and semi-arid environments play an essential role in the preservation and destruction of archeological sites. This is especially the case in the lower basin of the Colorado River at the eastern Pampa-Patagonia Transition of Argentina, as is illustrated by geoarchaeological and chronostratigraphic studies at a mid-Holocene hunter-gatherer site, La Modesta, where aeolian processes strongly influence the archeological record in dune sediments. At La Modesta, surface archaeological materials are numerous and well preserved, although the stratigraphic record is incomplete. Optically stimulated luminescence (OSL) dating of sediments that contain cultural material provides a chronology dating from ca. 8.2 ka but shows one or more hiatuses from ca. 6–2 ka in the sedimentary succession. Intense morphogenesis related to arid climates likely caused gaps in sedimentation, affecting the integrity and resolution of the archaeological record. This study helps explain mid-Holocene archaeological discontinuities throughout central Argentina and highlights the importance of considering taphonomic and geologic biases when dealing with the absence or reduction of the archaeological record in dryland regions. [ABSTRACT FROM AUTHOR]

This paper discusses how ecological restoration has been pursued through projects financed by L'Instrument Financier pour l'Environnement (LIFE) of the European Commission in Mediterranean and Black Sea coastal lagoon sites affiliated with the Natura 2000 network. While the LIFE programme started in 1992, the first project focusing on ecological restoration in a coastal lagoon setting in this eco-region was attributed in 1995. In total, 50% (27) of the 54 LIFE projects in the Mediterranean and Black Sea coastal lagoons comprised a worksite on ecological restoration. Eighteen finalized projects, all realized after 2008, have been sufficiently documented for our analysis. The ecological restoration works included (i) removing solid waste and alien invasive species, (ii) re-building lagoons, (iii) creating islets for bird colonies, (iv) restoring the hydrodynamics of the lagoons, and (v) restoring and protecting vegetation. The latter includes submerged aquatic vegetation in the lagoons, halophytes on tidal flats and in fringing salt marshes, freshwater marsh plants, and dune vegetation. Abandoned salt works (Salinas), originally created within the coastal lagoons or on their shoreline, represent significant areas that can be managed for conservation or restoration. Coastal lagoons are transitional waters, and successful restoration of water quality and aquatic communities must include the concept of the aquatic continuum. Combating eutrophication requires managing the watersheds of the lagoons to drastically decrease nutrient loadings. Unfortunately, these issues have only been marginally addressed by the LIFE projects, as they were too often limited by the perimeter of the Natura 2000 sites. In principle, the Water Framework Directive takes care of these issues and, according to an integrative vision, links them with the protected Natura 2000 sites. In practice, however, the LIFE projects and the water policies in the member states still suffer from sectorial approaches. [ABSTRACT FROM AUTHOR]

Aeolian desertification is a severe ecological and environmental problem in arid regions. Research on its spatio‐temporal distribution, modelling and driving force is necessary to prevent the development of aeolian desertification. In this study, the Moltsog Dune Field in Mongolia and the Ujimqin Dune Field in China were selected as the study areas, as both contain dunes under similar physical conditions. Using LANDSAT data from 1988, 1995, 2002, 2009, 2016 and 2020, the spatial–temporal distribution and the degree of development of aeolian desertification in the two dune fields over the past 30 years were compared. Two periods of high‐resolution images were then used to compare the surface morphological changes induced by aeolian desertification in these dune fields. Climatic and socio‐economic data of the same period were used to compare and analyse the potential causes of changes in aeolian desertification in these regions. The results show that: (1) Over the last 30 years, the degree and development rate of aeolian desertification in the Ujimqin Dune Field were generally higher than those in the Moltsog Dune Field, and the former had a high degree of fragmented aeolian desertification patches with an expanding range. (2) The main form of aeolian desertification is the reactivation of fixed dunes, which includes the development of blowouts on the flat grassland under the influence of human activities in the Ujimqin Dune Field. (3) Desertification in Moltsog is mainly affected by climatic factors, while that in Ujimqin is mainly driven by anthropogenic activities. The latter is specifically affected by the high grazing intensity before 2000 and increased mining activities after 2000. These findings provide a reference for comparing the aeolian desertification process and meaningful information for preventing and controlling aeolian desertification and enabling the sustainable development of dune fields in arid regions. [ABSTRACT FROM AUTHOR]

This paper performs an analysis of aeolian activity on Herschel crater on Mars from two dune fields in different topographical settings. At East field, between small simple craters, and at West the dune field is located inside a large impact crater, near to uplifted central peak. As source of data will be employed high resolution images (spatial resolution 0.25 m/pixel) and digital terrain models (DTM), with 1m / pixel spatial resolution, generated by HiRISE sensor of orbital probe Mars Reconnaissance Orbiter (MRO). Were measured horizontal parameters (Area, Azimuth length, width, and length/width ratio) and vertical parameters (height of crest (HC), height of slipface (HS), slipface slope, curvature) of 10 dunes in each field. In Field Herschel East, it is characterized by the unimodal wind regime. They have fat and free barchans on the uphill. The evolution is for axial barchanoids, with the presence of transverse dunes. It consists of a megabarchan interrupted by an impact crater 947m in diameter. The wind shadow generated by the main impact crater stands out as a phenomenon. The dunes have little azimuth variation. Ripple marks occur in the interdune region influenced by night wind and topography. Similar conditions were identified in similar terrestrial environments such as White Sands (New Mexico), Wolfe Creek (Australia) and Lagoa da Conceição (Santa Catarina). In Herschel Field West Acute Bimodal. They present normal and thin sloping downhill dunes, some anchored in Yardangs, with lots of azimuth variation. As a terrestrial analogue, we have the Liwa Oasis (United Arab Emirates / Saudi Arabia). [ABSTRACT FROM AUTHOR]

The impacts of climate change on the relationship between fluvial processes and dune landform evolution have been studied. However, the chronology data used to examine this relationship are deficient. The Keriya River has a glacial origin in the Kunlun Mountains on the south margin of the Tarim Basin. The river flows into the Taklimakan Desert, the second largest shifting-dune desert in the world. The dry channels and shifting dunes in this area provide an ideal opportunity to investigate fluvial and aeolian landform evolution processes and their relationship with climate change. We investigated this area during 2008–2011 and obtained 18 fluvial sediment samples from 16 sections for optically stimulated luminescence (OSL) dating. The results show that the ages ranged from 3.4–44.1 ka. Most of the samples (13) were Holocene in age, around 11 ka, 8–9 ka, 5–6.5 ka, 4.6 ka, and 3.4–3.7 ka and were distributed along ancient river channels around sites of Yuansha and Karadun. Two samples close to the Hotan River (38–47 ka) fall within the Marine Isotope Stage 3 (MIS3). Three samples (from one section) were located near ancient channels flowing towards the Yuansha Site and had ages of around 14.5 ka, i.e., during the Last Glacial Maximum (LGM). The analyses of the sediment samples and OSL ages suggest that the Keriya River flooded in the Holocene, the LGM, and MIS3. Fluvial sediments provided the source material for the dunes, and fluvial processes affected the landform evolution in the lower Keriya River. Our results suggest that most of the dunes covered in fluvial sediments in the lower reaches and the area west of the Keriya River developed since the Holocene. This differs from the results of previous studies, which suggested that they developed since the Han (202BC–220AD) and Tang (618–907AD) dynasties. The OSL ages of the fluvial sediments are consistent with the reported deglaciation (after glacial advance) ages in the alpine mountains surrounding the Tarim Basin. This suggests that climate fluctuations may have affected the occurrence of floods and the formation of dunes in the Taklimakan Desert. [ABSTRACT FROM AUTHOR]

Wind flow over coastal foredunes adapts to vegetation, resulting in spatial gradients in bed shear stresses that contribute to the formation of localized bedforms. Understanding, and having the capability to numerically predict, the distribution of sediment deposited within sparsely vegetated dune complexes is critical for quantifying the ecological, protective, and economic benefits of dune management activities. Data from wind tunnel experiments have indicated that there is a spatial lag from the canopy leading edge to a downwind location where sediment deposition first occurs. The length scale of this deposition lag is further quantified here using new field measurements of aeolian sediment transport across sparsely vegetated managed dune systems in Oregon, USA. We develop a deposition lag length scale parameter using both lab and this new field data and then incorporate this parameter into the process‐based aeolian sediment transport model, Aeolis, which also includes a new far‐field shear stress coupler. Results from numerical simulations suggest that the spatial deposition lag effect is significant for model skill in sparsely vegetated dunes. We observe with field and laboratory observations that, as canopy density increases, the length of the deposition lag decreases. As such, within the model framework the implementation of the deposition lag length does not affect the results of models of coastal dune geomorphological evolution within higher density canopies. Dune canopy density can vary due to natural (e.g., storm overwash, burial, die‐off) or anthropogenic (e.g., managed plantings, dune grading) processes. [ABSTRACT FROM AUTHOR]

Abstract A Silurian shift in fluvial stratigraphic architecture, coincident with the appearance of terrestrial vegetation in the fossil record, is traditionally cited as evidence for exclusively shallow, braided planforms in pre‐vegetation rivers. While recent recognition of deep, single‐thread channels in pre‐Silurian strata challenge this paradigm, it is unclear how these rivers maintained stable banks. Here, we reconstruct paleohydraulics and channel planform from fluvial cross‐strata of the 1.2 Ga Stoer Group. These deposits are consistent with deep (4–7 m), low‐sloping rivers (2.7 × 10−4 to 4.5 × 10−5), similar in morphometry to modern single‐thread rivers. We show that reconstructed bank shear stresses approximate the cohesion provided by sand‐mud mixtures with 30%–45% mud—consistent with Stoer floodplain facies composition. These results indicate that sediment cohesion from mud alone could have fostered deep, single‐thread, pre‐vegetation rivers. We suggest that the Silurian stratigraphic shift could mark a kinematic change in channel migration rate rather than a diversification of planform.

In Germany, including Lower Saxony, Eryngium maritimum (Sea Holly) is a highly endangered plant species protected by law. The species is known mainly from shifting dunes with Ammophila arenaria (EU habitat type 2120) and from younger calcareous soils of fixed coastal dunes with herbaceous vegetation (EU habitat type 2130). Eryngium maritimum was reported from all the large East Frisian Islands before 1900. The aim of this study was to re-map the distribution of this species along the coast of Lower Saxony, particularly in the Lower Saxon Wadden Sea National Park, and to record the habitats in which it occurs. Methods: E. maritimum was mapped with a mobile App-based geographic information system by rangers and other staff of the National Park Authority in 2020. On Spiekeroog, due to the large number of individual plants, mapping started in 2018, In addition, in 2022 some areas on the mainland not originally foreseen (i.e. Wangerland, Cuxhaven) were surveyed. The number of vegetative and flowering individuals were recorded. In general, shoots within 10 cm of each other were considered to be from a single plant, but sometimes a clear differentiation was not possible. To compare former and recent distribution, old records from the NLWKN (Lower Saxon agency for water bodies, flood protection and nature conservation) and the BfN (Federal Agency for Nature Conservation) were used. To determine the importance of sand accretion (wind-blown sand) to species distribution, relationships to coastal defence dunes as well as habitat types were studied. Results: E. maritimum is recorded from 73 standardised grid cells of about 1.2 × 1.8 km ("Minutenfelder"/grid cells) in Lower Saxony in the period 1981-2022. In more than 50% of these "Minutenfelder" (grid cells) with records between 1981-2015, E. maritimum was confirmed; it was firstly recorded in 16 of 73 "Minutenfelder" (grid cells). The measured population in Lower Saxony is over 55,000 individuals, with the largest numbers on the islands of Spiekeroog and Wangerooge. The most suitable habitats for the species were those characterised by low to moderate sand accretion. Thus, more than 75% of the plants occur in dunes without coastal defence measures or in areas seawards of the coastal defence measures. Dunes which form part of coastal defences are regularly planted more or less with Ammophila arenaria or Calammophila baltica. Regarding the dune series, 85% of the plants are found in the zone from the higher beach landwards to young grey dunes. With succession towards older grey and brown dunes the number of individuals declined. In contrast to the positive impact of sand accretion, rabbits have a negative impact on the population size of Sea Holly. The populations of Sea Holly were larger on islands without rabbits. On islands with high grazing pressure by rabbits (Borkum, Memmert, Norderney, Baltrum, Minsener Oog) no or only very few individuals of Sea Holly occurred. [ABSTRACT FROM AUTHOR]

Bedload sediment transport in rivers can cause impacts, such as bed erosion/deposition, sandbank formation and changes in flow capacity. Bedload sampling techniques have limitations related to spatial and temporal resolution. These constraints are more relevant in rivers with dunes and high sediment transport. This paper presents a comparison between bedload transport rates estimated with direct and indirect methods in a river with sand dunes. The case study area is a stretch of the Taquari River, in Brazil. Surveys were carried out on three consecutive days, during a flood season. A SonTek M9-ADCP with HydroSurveyor capabilities activated was used to simultaneously measure bathymetry and water velocities throughout a river reach, and also to perform moving-bed tests at six verticals along a predefined cross-section. A mechanical trap (Helley–Smith) was used to collect bedload samples at the same time and positions where the moving-bed tests were performed. Sediment transport was calculated and compared following different approaches: (1) ADCP-BT (Bottom Tracking); (2) modified ISSDOTv2 method (dune tracking); (3) HelleySmith mechanical trap; (4) and five empirical equations. The results showed good agreement between the methodologies, indicating the potential of using ADCPs for hydro sedimentological studies due to the advantages of integrating bathymetry, flow velocity and bedload data. [ABSTRACT FROM AUTHOR]

Long‐term and seasonal geomorphological changes at Padre Island, Texas are identified and linked with potential external drivers. Aerial and satellite images from 1950 to 2018, monthly images from 2019 to 2020, and a 2018 LiDAR data set are used to assess long‐term and seasonal geomorphological changes within a 50 km2 area of Padre Island near Port Mansfield, Texas. Trends in landcover are evaluated by mapping and comparing the relative areal coverage of each facies. Vegetated dunes, absent initially, emerged in the fore‐island and expanded into the back‐barrier to cover 14% of the study area. The active vegetation‐free back‐barrier dune field steadily decreased in areal extent from 12% to 6% as vegetation spread. Nebkha dune coverage fluctuated between 4% and 7%. Expansive microbial mats colonized the wind tidal and deflation flats surrounding the vegetated dunes and back‐barrier dune field giving rise to a remarkably different landscape over the 50‐year period studied. An assessment of external forcing factors identifies increased rates of relative sea level rise and decreased sediment influx as the most likely primary factors driving the geomorphological changes. These changes have induced a widespread shift toward stabilization of island sediments by vegetation and microbial mats, which in turn has starved the back‐barrier of sediments resulting in low rates of accretion and increased flooding. These findings highlight the sensitivity of the back‐barrier and, in particular, the dune facies to changes in sea level and sediment supply, and show that microbial mats are effective at stabilizing island sediments and may be harbingers to barrier island response to rising sea level. As shown in this study, long‐term monitoring of geomorphic facies changes and topography can detect important shifts in the island state that can be used to inform decision making for these sensitive coastal landscapes. [ABSTRACT FROM AUTHOR]

Sandy beaches, essential components of coastal landscapes, are increasingly threatened by urbanization, resource extraction, and climate change, jeopardizing their ecological integrity and scenic value. This study assesses the health and scenic quality of 100 sandy beaches along the Uruguayan coast, influenced by the Ro de la Plata estuary, using the Coastal Scenery Evaluation System (CSES) and a dune integrity assessment as indicators of ecosystem health. The analysis identified urbanization as the primary driver of beach degradation, with the most urbanized beaches, particularly those in the inner and outer estuary macrozones, exhibiting the lowest scenic and ecological values. In contrast, beaches with greater dune integrity and lower human impact, especially those in the oceanic macrozone, demonstrated better scenic quality and ecological health. This study emphasizes the role of natural features, such as dunes and natural vegetation, in sustaining beach health, while stressing the urgent need for sustainable management practices to safeguard the ecological and cultural value of these fragile ecosystems. The findings offer critical insights for coastal governance, management, and conservation, advocating for the protection of less developed beaches and the restoration of degraded beaches through scientifically robust management plans. This approach also emphasizes the importance of inclusive decision-making, fostering active societal engagement to enhance long-term resilience and sustainability in areas threatened by coastal grabbing. • Scenic assessment of 100 beaches along the Uruguayan coast. • Lowest scenic values in highly urbanized estuarine beaches. • Higher dune integrity correlates with beach health and scenic quality. • Urbanization identified as the primary driver of beach degradation in Uruguay. • Urgent need for comprehensive beach management and conservation strategies. [ABSTRACT FROM AUTHOR]

Mega nourishments are innovative Nature-based Solutions to protect against coastal erosion and flooding. By upscaling the volume of sand nourishments, mega nourishments enhance coastal safety while creating new space for recreation and nature development. The application of such large nourishment volumes can significantly alter natural beach-dune morphology, with an unclear effect on the long-term evolution of the beach-dune system. The DuBeVeg model, a bio-geomorphological Cellular Automata model, was extended to incorporate the typical surface armouring and longshore coastline development of mega nourishments. The extended model was successfully validated with morphodynamic data from the Sand Motor mega nourishment and was used to explore the long-term dune development of idealized bell-shaped mega nourishments. Over a 50-year time span, the typically artificially high and wide beach of a mega nourishment resulted in the seaward expansion of the foredune zone whilst a more natural, lower beach elevation resulted in a greater volume of the foredune zone in the long-term. A faster diffusion of the initially bell-shaped mega nourishment gave rise to a lesser advance and a more alongshore-uniform width of the foredune zone. Furthermore, the armour layer that develops when the nourishment material is less well-sorted and coarser than native beach sand, led to the emergence of more scattered and isolated dunes compared to a nourishment with native beach sand. These model results show potential for investigations into design optimisation of the subaerial development of Nature-based Solutions for sandy coasts. • DuBeVeg can enhance understanding of dune development following mega nourishments. • Artificially high and wide mega nourishments stimulate dune seaward expansion. • Lowering of the mega nourishment platform increases dune volume on the long-term. • Unsorted coarser sediment forming an armour layer leads to more scattered dunes. • A more energetic wave climate leads to a more alongshore uniform dune width. [ABSTRACT FROM AUTHOR]

Sand grains are ubiquitous in the Earth's system, and are found in different environmental settings globally, but sand itself as a physical object has multiple conflicting meanings with respect to both its agglomeration into landforms such as sand dunes and beaches, and how sand and its dynamics have cultural significance and meaning. This study takes a transdisciplinary approach towards examining the multiple meanings of sand, focusing on sand as a spatiotemporal pheneomenon that exists in different contexts within the Earth system. The nature and spatiotemporalities of sand are framed in this study through the concepts of presence, absence and transience, which are key interpretive approaches that lie at the interface of how the physical and phenomenological worlds interact with each other. This is a new and innovative approach to understanding people–environment relationships. These concepts are then discussed using the examples of the dynamics of and values ascribed to desert dune and sandy beach landscapes, drawn from locations globally. These examples show that the dynamic geomorphic changes taking place in sand landscapes (sandscapes) by erosion and deposition (determining the presence and absence of sand in such landscapes) pose challenges for the ways in which people make sense of, locate, interact with and value these landscapes. This uncertainty that arises from constant change (the transience of sandscapes) highlights the multiple meanings that sandscapes can hold, and this represents the comforting yet also unsettling nature of sand, as a vivid symbol of human–Earth relationships. [ABSTRACT FROM AUTHOR]

We analyzed the diet of Athene cunicularia cunicularia in order to identify and compare prey items in dune populations in Santa Catarina, Brazil: Interpraias (INT), Praia Brava (BRA), Praia Central (NAV) and Peninsula (BVE). Due to the characteristics of urbanization in these regions, we hypothesized that there would be greater abundance and consumption of urban insect pests in the areas of BRA, NAV, and INT than in BVE. We collect owl pellets monthly in 2017. The non-parametric analysis ANOVA was applied to identify differences in pellet weights and niche amplitude between populations and seasons and PERMANOVA was applied to identify differences between prey items. Were collected 1064 pellets containing 20 prey items, including: invertebrates (Arachnida, Insecta and Crustacea Malacostraca – 83%), vertebrates (Osteichthyes, amphibians, Reptilia, birds and Mammalia – 8.6%), seeds (6.38%) and miscellaneous materials of anthropic origin (0.19%). There was no difference in the pellet weights, but the diets observed in INT and BRA were significantly different, a result that may be a reflection of the microenvironments in which the burrowing owl lives. This shows that, in addition to a generalist diet, this species has the capacity to adapt to urban changes. [ABSTRACT FROM AUTHOR]