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Taborda, R. and Silva, A.N., 2024. Modeling shoreline evolution on platform beaches. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 283-288. Charlotte (North Carolina), ISSN 0749-0208. Embayed and shore platform beaches, common along rocky coastlines, are highly vulnerable to changes in oceanographic conditions and sediment supply. Coastal changes in embayed beaches involve sediment redistribution within embayments and exchanges between neighboring embayments, particularly in open or leaky sediment cells. Despite their importance, there is a shortage of shoreline models that couple shoreline evolution with sediment bypassing. The study introduces SEM-PLAT, a shoreline evolution model applicable to both low-lying sandy coasts and shore platform beaches on rocky coasts. Unlike traditional models, SEM-PLAT considers the dynamic behavior of the beach toe over time and sediment exchanges between embayments. It incorporates spatial gradients in wave-induced longshore sediment transport and a dynamic profile model, providing a comprehensive framework for complex shoreline evolution. Applications of SEM-PLAT demonstrate its effectiveness in simulating coastal processes, including beach development, rotation, and sediment bypassing. This model highlights key coastal geomorphological processes and offers a versatile tool for shoreline evolution studies and coastal management strategies.

The way of movement of the machine-tractor units in the field influences the efficiency of the performed operations. A way of movement must be chosen in which the length of the non-working moves and the width of the headland are minimal. When moving in an irregularly shaped field, the length of the non-working moves and the width of the headland depend on the angle between the direction of movement of the unit and the field boundary. In the article dependences for determining the length of the non-working move when performing open and closed fishtail turns with a rectilinear reverse move, which is not parallel to the field boundary, as well as for determining the width of the headland required for their execution are derived. It was found that the non-working move is the shortest and the width of the headland is the smallest when performing a closed fishtail turn and the direction of alternation of the working moves in the field from right to left.

In arable fields, plant species richness consistently increases at field edges. This potentially makes the field edge an important habitat for the conservation of the ruderal arable flora (or ‘weeds’) and the invertebrates and birds it supports. Increased diversity and abundance of weeds in crop edges could be owing to either a reduction in agricultural inputs towards the field edge and/or spatial mass effects associated with dispersal from the surrounding landscape. We contend that the diversity of weed species in an arable field is a combination of resident species, that can persist under the intense selection pressure of regular cultivation and agrochemical inputs (typically more ruderal species), and transient species that rely on regular dispersal from neighbouring habitats (characterised by a more ‘competitive’ ecological strategy). We analysed a large dataset of conventionally managed arable fields in the UK to study the effect of the immediate landscape on in‐field plant diversity and abundance and to quantify the contribution of spatial mass effects to plant diversity in arable fields in the context of the ecological strategy of the resulting community. We demonstrated that the decline in diversity with distance into an arable field is highly dependent on the immediate landscape, indicating the important role of spatial mass effects in explaining the increased species richness at field edges in conventionally managed fields. We observed an increase in the proportion of typical arable weeds away from the field edge towards the centre. This increase was dependent on the immediate landscape and was associated with a higher proportion of more competitive species, with a lower fidelity to arable habitats, at the field edge. Synthesis and applications. Conserving the ruderal arable plant community, and the invertebrates and birds that use it as a resource, in conventionally managed arable fields typically relies on the targeted reduction of fertilisers and herbicides in so‐called ‘conservation headlands’. The success of these options will depend on the neighbouring habitat and boundary. They should be placed along margins where the potential for ingress of competitive species, that may become dominant in the absence of herbicides, is limited. This will enhance ecosystem services delivered by the ruderal flora and reduce the risk of competitive species occurring in the crop. Conserving the ruderal arable plant community, and the invertebrates and birds that use it as a resource, in conventionally managed arable fields typically relies on the targeted reduction of fertilisers and herbicides in so‐called ‘conservation headlands’. The success of these options will depend on the neighbouring habitat and boundary. They should be placed along margins where the potential for ingress of competitive species, that may become dominant in the absence of herbicides, is limited. This will enhance ecosystem services delivered by the ruderal flora and reduce the risk of competitive species occurring in the crop.

Rip currents represent a significant coastal hazard, and their dynamics have been studied globally on various types of coastlines. However, research on their characteristics along the headland-bay coasts of Hainan Island, China, remains limited. Hainan Island features numerous headland-bay beaches, most of which are subject to varying degrees of rip current risk. To address this gap, this study established a high-resolution numerical model for rip currents in Zhu Bay, Sanya, based on the FUNWAVE-TVD model. By integrating numerical simulations with remote sensing imagery and comprehensively considering the effects of topography, wave parameters, and tides, we systematically analyzed the distribution characteristics and dynamic patterns of rip currents in Zhu Bay. The results provide a reference for research on rip current hazards and their prevention along typical coastlines of Hainan Island.

Machine-tractor units with mounted machines most often perform fishtail turns with a curvilinear reverse move when changing the direction of movement at the end of the field. In an irregularly shaped field, the shape of turn and the width of the headland depend on the angle between the direction of the working move and the field boundary and the direction in which the working moves alternate in the field. The article presents dependences for determining the length of open and closed fishtail turns with a curvilinear reverse move and the width of the headland. An analysis of the influence of the angle between the direction of movement and the field boundary on the length of the non-working move and the width of the headland is made. It has been found that when the unit moves in the field from right to left, the length of the non-working move is the smallest and constant, except in cases where the angle between the direction of movement of the unit and the field boundary is very small. The headland has a smaller width in open turn from left to right and closed turn from right to left. When the angle between the direction of movement and the field boundary is small, the closed turn must be performed when moving in the field from left to right.

Shorelines face growing threats due to climate change and diminishing sand supply. Coastal headlands, common rocky features along coastlines, are crucial in shaping hydrodynamics and sediment transport. Yet, the influence of future climate conditions, including sea‐level rise (SLR) and intensified storm energy on complex shorelines with headlands has remained relatively unexplored. In this study, we model changes in hydrodynamics and headland bypassing under different SLR and higher storm wave scenarios. Our findings reveal the formation of circulation cells on both sides of a headland, where wave energy converges around the headland zone. Future climate conditions result in larger storm waves on the beach. However, SLR enhances nearshore currents through a landward shifting of the circulation cells, while higher storm waves intensify offshore flow currents due to the seaward movement of the cells. This effect, in turn, increases the potential for headland sediment bypassing. Plain Language Summary Coastal headlands, prominent rocky features along open coastlines, play a crucial role in protecting nearby beaches from strong waves and erosion. They also affect how sand is exchanged between different beaches. We use a model to explore how future climate conditions including sea‐level rise (SLR) and larger storm waves influence coastal waves, littoral currents, and the transport of sand around headlands. Our findings reveal that headlands converge wave energy forming circulation flow cells. SLR results in stronger nearshore currents, driven by the landward movement of the rotating flow cells. In contrast, larger storm waves can move the rotating flow cells seaward, thereby increasing offshore current strength and the potential for sand transport around the headland. Understanding how coastal waves, flow and sediment transport change under future climate conditions will help determine coastal resilience. Key Points The formation of circulation cells and wave energy convergence around headlands during storms reduce bottom shear stress at the beach Sea‐level rise increases wave heights, currents, and bed shear stress in the nearshore because of landward shifting of the circulation cells Higher storm waves expand the surf zone, shift circulation cells seaward, and enhance potential headland sediment bypassing

Context Urbanisation is pervasive across landscapes and seascapes and leads to the loss, degradation and fragmentation of many natural ecosystems and this has widespread consequences for animals and the ecological functions they support. While the impacts of urbanisation are understood for many individual coastal ecosystems in isolation, it is unclear how these impacts influence animal assemblages and ecological functions across different coastal ecosystems within the same landscape. Objectives We aimed to determine how urbanisation modifies fish and crustacean assemblages and the function of carrion consumption across multiple coastal ecosystems set within the same landscape in eastern Australia. Methods We sampled fish and crustacean assemblages in three distinct coastal ecosystems (estuaries, rocky headlands and surf zones) with baited remote underwater video systems and quantified rates of carrion consumption using scavenging assays. Results Urbanisation had negative effects on the richness and abundance of coastal fish and crustaceans and the ecological function of carrion consumption, and these impacts were almost always consistent across estuaries, rocky headlands and surf zones. Species richness and abundance were lowest at the most urbanised sites, whereas rates of carrion consumption were lowest at sites closest to urbanised areas, across all ecosystems. Conclusions We highlight the negative effects of urbanisation on coastal fish and crustacean assemblages, and a vital ecological function, and the consistency of these effects on distinct coastal ecosystems located within the same landscape. Managing the pervasive impacts of urbanisation on animal assemblages and ecological functions will, therefore, require targeted approaches that address the underlying impacts of urbanisation across multiple coastal ecosystems.

Claudino-Sales, V.; Wang, P., and Carvalho, A.M., 2018. Interactions between various headlands, beaches, and dunes along the coast of Ceará State, Northeast Brazil. The equatorial coast of NE Brazil consists of long and wide sandy beaches, segmented by rhythmic headlands, sometimes with seacliffs. Large and extensive mobile transgressive dunefields distribute up to 6 km landward of the coastline. The coastal area of Ceará state, as examined in this study by the means of measurements, field work, and remote sensing, illustrates a characteristic morphology composed of interactive headland, beach, and dune systems. Under persistent unidirectional wind and wave forcing, the morphodynamics of the studied coast is strongly controlled by the headlands because they produce an interruption of the longshore sand transport at their contact, resulting in accretion updrift of the headland and in erosion downdrift of the headland. The headland bypass dunefield activates one major mechanism and dynamics of the system headland-beach-dune because they refeed the beaches in the process of erosion downdrift. Littoral bypass is also an important process, supplying the cell with new sand, together with the erosion that takes place in the zetaform beach. Such a unique system can be strongly affected by anthropogenic activities, which can influence nearly all the factors at all temporal and spatial scales.

The independent and repeated adaptation of populations to similar environments often results in the evolution of similar forms. This phenomenon creates a strong correlation between phenotype and environment and is referred to as parallel evolution. However, we are still largely unaware of the dynamics of parallel evolution, as well as the interplay between phenotype and genotype within natural systems. Here, we examined phenotypic and genotypic parallel evolution in multiple parapatric Dune-Headland coastal ecotypes of an Australian wildflower, Senecio lautus. We observed a clear trait-environment association in the system, with all replicate populations having evolved along the same phenotypic evolutionary trajectory. Similar phenotypes have arisen via mutational changes occurring in different genes, although many share the same biological functions. Our results shed light on how replicated adaptation manifests at the phenotypic and genotypic levels within populations, and highlight S. lautus as one of the most striking cases of phenotypic parallel evolution in nature.

Studies of exhumed subduction shear zones indicate that metamorphism and metasomatism of the oceanic lithosphere influence the composition, structure, and rheology of megathrust faults, particularly deep along the plate boundary (>30 km). However, less is known about the effects that fluid‐mediated chemical reactions have on the rheological evolution of oceanic crust at shallower depths, which may control diverse modes of fault slip and down‐stepping of the plate boundary into oceanic crust. Here, we present a structural and geochemical study of fault rocks from the Rodeo Cove thrust zone (RCT) in California to examine feedbacks between deformation and metasomatism of oceanic crust in a shallow subduction thrust environment (<15 km). At the RCT, deformation is accommodated by a dense network of reddish and greenish cataclasites, which surround altered basalt blocks containing abundant calcite veins and cement. Electron microprobe analyses show that the altered basalt is primarily composed of clinopyroxene, albite, chlorite, and pumpellyite, whereas the cataclasite is dominated by ferroaluminoceladonite (K‐ and Fe‐rich mica) and iron‐oxyhydroxides interlayered with well‐crystallized sheets of aluminoceladonite. Our findings suggest that subduction‐related faulting and cataclasis increased permeability within the basalt‐hosted shear zone, promoting extensive K‐metasomatism, first by oxidizing seawater and later by hydrothermal fluids sourced from subducted sediment and/or altered oceanic crust at greater depths. Moreover, contrasting deformation mechanisms between the less altered basalt and strongly K‐metasomatized cataclasite, combined with their constitutive properties quantified from deformation experiments, indicate that K‐metasomatism significantly decreased the frictional strength of oceanic crust causing strain to localize in the RCT.