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Sporobolus alterniflorus (S. alterniflorus) is a widespread invasive plant that poses significant threats to coastal wetland ecosystems and local economies worldwide. However, most existing management methods for S. alterniflorus are costly and provide only temporary relief due to reoccurrences and reinvasion. Additionally, limited attention has been paid to examining the application of invasion mechanisms in the design of management measures, hindering the development of effective strategies. In this paper, we reviewed the literature on the mechanisms and management of S. alterniflorus invasion. We identified the key factors enabling invasion mechanisms, analyzed how they are targeted in current control methods, and pointed out their implications for future research. We recommend that the invasion mechanisms of S. alterniflorus should be comprehensively considered during the design of management measures. Furthermore, future research on invasion mechanisms could focus on the joint effects and the relative roles of individual factors in successful invasion, the impact of S. alterniflorus invasion on the coupled human and natural systems, and the systematic review of studies at different scales. [ABSTRACT FROM AUTHOR]

Background: The study of soil organic carbon characteristics and its relationship with soil environment and vegetation types is of great significance to the evaluation of soil carbon sink provided by inland salt marshes. This paper reports the characteristics of soil organic carbon fractions in 0–50 cm soil layers at four vegetation communities of the Qinwangchuan salt marsh. Results: (1) The soil organic carbon content of Phragmites australis community (9.60 ± 0.32 g/kg) was found to be higher than that of Salicornia europae (7.75 ± 0.18 g/kg) and Tamarix ramosissima (4.96 ± 0.18 g/kg) and Suaeda corniculata community (4.55 ± 0.11 g/kg). (2) The soil dissolved organic carbon, particulate organic carbon and soil microbial biomass carbon in 0–50 cm soil layer of Phragmites australis community were higher, which were 0.46 ± 0.01 g/kg, 2.81 ± 0.06 g/kg and 0.31 ± 0.01 g/kg, respectively. (3) Soil organic carbon was positively correlated with dissolved organic carbon, particulate organic carbon, and microbial biomass carbon, and negatively correlated with easily oxidized organic carbon. (4) Above-ground biomass has a strong direct positive effect on soil organic carbon, total nitrogen and pH have a strong direct positive effect on microbial biomass carbon content, pH and average density have a strong direct negative effect on easily oxidized organic carbon, and particulate organic carbon. Conclusions: The interaction between plant community characteristics and soil factors is an important driving factor for soil organic carbon accumulation in inland salt marshes. [ABSTRACT FROM AUTHOR]

Salt marshes play a critical role in ecological functioning and have significant economic value. Hydrological elements are considered to be one of the major contributors to salt marsh degradation. However, how hydrological connectivity affects salt marshes remains poorly investigated at fine scales. This paper used spatial analysis and statistical methods to investigate the impact of hydrological connectivity on the spatial and temporal distribution characteristics of salt marsh vegetation in two natural succession areas of the Liao River Delta wetland in 2020 and 2021 by selecting vegetation area, NDVI, tidal creeks area, distance to tidal creeks, and the Index of Connectivity, using 1 m Gaofen-2 data and 0.2 m aerial topographic data. The study found that the area and growth status of vegetation and the overall connectivity in 2021 were better than that in 2020, while the west bank of the Liao River was better than that on the east bank. Phragmites australis showed a round island distribution pattern primarily at the end of tidal creeks. The differences between different hydrological connectivity and vegetation area were significant in 2021. The vegetation area was the largest under poor and moderate connectivity. We also found that within a distance range of 0–6 m from tidal creeks, the vegetation area increased with increasing distance, but beyond 6 m, the vegetation area decreased with increasing distance. Our results showed that poor and moderate connectivity conditions were more suitable for vegetation growth. The threshold value of 6 m can provide an important reference for wetland vegetation restoration in the Liao River Delta wetland. [ABSTRACT FROM AUTHOR]

The pulmonate gastropod genus Ellobium has its greatest diversity in the modern Indo-West Pacific Region (IWP). Its origin, however, is traced to the Early Oligocene of the Northeastern Atlantic and the Western Tethys Region. Two Ellobium species are documented from the Rupelian of France and Italy and a new species is recorded from the Chattian of Hungary: Ellobium kerwaensis nov. sp. The first records in the IWP are known from the Early Miocene, suggesting an eastward range expansion of the genus around the Oligocene/Miocene boundary, when Ellobium became extinct in the European seas. Extant Ellobium species are bound to habitats above the high tide line in salt marshes and mangroves. Comparable environmental requirements are expected for the fossil congeners. Ellobium may derive from Eocene ancestors, such as the Bartonian Eoellobium heberti from the Northeastern Atlantic. Eoellobium is introduced in this paper as a new genus. [ABSTRACT FROM AUTHOR]

Ecosystems across the United States are changing in complex and surprising ways. Ongoing demand for critical ecosystem services requires an understanding of the populations and communities in these ecosystems in the future. This paper represents a synthesis effort of the U.S. National Science Foundation‐funded Long‐Term Ecological Research (LTER) network addressing the core research area of "populations and communities." The objective of this effort was to show the importance of long‐term data collection and experiments for addressing the hardest questions in scientific ecology that have significant implications for environmental policy and management. Each LTER site developed at least one compelling case study about what their site could look like in 50–100 yr as human and environmental drivers influencing specific ecosystems change. As the case studies were prepared, five themes emerged, and the studies were grouped into papers in this LTER Futures Special Feature addressing state change, connectivity, resilience, time lags, and cascading effects. This paper addresses the "connectivity" theme and has examples from the Phoenix (urban), Niwot Ridge (alpine tundra), McMurdo Dry Valleys (polar desert), Plum Island (coastal), Santa Barbara Coastal (coastal), and Jornada (arid grassland and shrubland) sites. Connectivity has multiple dimensions, ranging from multi‐scalar interactions in space to complex interactions over time that govern the transport of materials and the distribution and movement of organisms. The case studies presented here range widely, showing how land‐use legacies interact with climate to alter the structure and function of arid ecosystems and flows of resources and organisms in Antarctic polar desert, alpine, urban, and coastal marine ecosystems. Long‐term ecological research demonstrates that connectivity can, in some circumstances, sustain valuable ecosystem functions, such as the persistence of foundation species and their associated biodiversity or, it can be an agent of state change, as when it increases wind and water erosion. Increased connectivity due to warming can also lead to species range expansions or contractions and the introduction of undesirable species. Continued long‐term studies are essential for addressing the complexities of connectivity. The diversity of ecosystems within the LTER network is a strong platform for these studies. [ABSTRACT FROM AUTHOR]

The two‐way interactions between biological and physical processes, bio‐geomorphic feedback, play a vital role in landscape formation and evolution in salt marshes. Patchy vegetation represents a typical form of scale‐dependent feedback in salt marshes and is primarily responsible for the formation of efficient drainage networks. The intuitive manifestation of scale‐dependent feedback is the heterogeneity of flow and landscape. Process‐based modeling is an essential tool for exploring flow heterogeneity, but calculations for small spatial scales and over long time frames can be prohibitively costly. In this study, we proposed a deep learning model architecture, UNet‐Flow, based on convolutional neural networks (CNNs), which is used to build a surrogate model to simulate a flow field induced by salt marsh patchy vegetation. After optimizing and evaluating the model, we discovered that UNet‐Flow exhibits a speed improvement of over four orders of magnitude compared to single‐process simulations using the free surface flow model TELEMAC‐2D, with acceptable levels of error. Furthermore, we proposed an approach that combines the process‐based model SISYPHE with the deep learning method to model geomorphic heterogeneity. After numerous simulations of flow heterogeneity modeling using UNet‐Flow, we obtained a significant logarithmic relationship between scale‐dependent feedback strength and vegetation stem density, and an ascending‐descending trend in feedback strength was observed as the number or surface area of vegetation patches increased. Finally, we investigated the relationship between geomorphic heterogeneity and vegetation‐related variables. This study represents a noteworthy effort to study bio‐geomorphology using deep learning methods. Plain Language Summary: Bio‐geomorphic feedback refers to the two‐way interactions between biological and physical processes. It is a crucial factor in the formation and evolution of salt marsh landscapes. Vegetation patches are typically found at the front edge of salt marshes. These patches extensively influence the landscapes by influencing the flow, which induces the formation of efficient drainage channels. Due to the critical role vegetation patches play in the development of landscapes, numerical simulation of bio‐geomorphic feedback requires sub‐meter scale grid cells, thus resulting in high computational power needed for long‐term simulations. In this paper, we introduced a deep‐learning‐based model to simulate the flow heterogeneity induced by vegetation patches. Furthermore, we employed a hybrid approach combining process‐based modeling and deep learning to simulate geomorphic heterogeneity. The deep‐learning model is significantly faster than a traditional model with an overall acceptable error. After numerous simulations, we identified a significant logarithmic relationship between bio‐geomorphic feedback strength and vegetation density. Additionally, we observed noteworthy associations between geomorphic heterogeneity and patch distribution, vegetation stem density, and suspended sediment concentration. This finding highlights the model's potential importance in analyzing small‐scale bio‐geomorphic processes. Key Points: A deep learning architecture based on convolutional neural networks (CNNs) was introduced to model flow and geomorphic heterogeneityThe CNN‐based model significantly improves computational efficiency while maintaining an acceptable overall errorThe distribution of vegetation patches plays a crucial role in shaping the fundamental morphology of tidal creeks [ABSTRACT FROM AUTHOR]

In Florida, mangrove-dominated wetlands have been manipulated and managed largely for control of mosquitoes or to make way for human development since the late 1800s. More recently, many wetlands have been rehabilitated as their contributions to estuarine ecosystems became apparent and techniques that restored valuable contributions without compromising control of mosquitoes became available. This paper documents the history of manipulations largely used to control mosquito production in wetlands on the east coast of Florida, which have included ditching, filling, and impounding. It describes the management of these environmentally sensitive habitats since World War II and approximately 40 years of effort to rehabilitate these systems and improve their management. Improvements have been accomplished via adaptive management, science-based decision making and engagement of diverse groups of resource managers and stakeholders. Interagency efforts to provide balanced management of these wetlands are discussed, and work is presented to demonstrate the outcomes from rehabilitating impoundments in the Indian River Lagoon. These strategies for management and rehabilitation should provide guidance for restoring and conserving critical ecosystem services delivered by mangrove-dominated wetlands elsewhere, including survival in the face of future environmental changes. [ABSTRACT FROM AUTHOR]

To investigate the spatial and temporal variations of sulfur (S) in plant-soil systems of Phragmites australis (PA, native invasive species) and Cyperus malaccensis (CM, common native species) marshes, in situ filed sampling was conducted in the two marshes at different seasons. Results showed that the variations of total sulfur (TS) contents in soils differed among seasons or marshes. Higher levels of TS in soils of PA marsh generally occurred in winter and summer, while those of CM marsh were observed in spring and autumn. Except for winter, the levels of TS in topsoil of CM marsh in other seasons were much higher than those of PA marsh. The variations of TS contents in soils of PA and CM marshes were dependent on the differences in physical and chemical properties (particularly electrical conductivity) of the two marshes and the differences in S absorption and utilization of the two plants. The levels of TS and the accumulation factors of S (AFS) in PA or CM differed within seasons or tissues, which could be interpreted by the differences in growth rhythm and ecological traits between the two plants. The roots/stems (R/S) and roots/leaves (R/L) ratios in PA or CM were mostly than 1, while the stems/leaves (S/L) ratios in both plants were less than 1. Allocations of S in roots of PA were generally higher than those of CM, while the values in aboveground parts of PA were much lower than those of CM. This paper found that the two plants might adopt different strategies for S accumulation and allocation to maintain their competitiveness. The PA might compete primarily by increasing the S accumulation capacities of its roots, whereas the CM might resist the spatial expansion of PA by enhancing the S accumulation capacities of its aboveground tissues. [ABSTRACT FROM AUTHOR]

Salt marshes provide valuable ecosystem services, which are influenced by their interaction with current and waves. On the one hand, current and waves exert hydrodynamic force on salt marsh plants, which shapes the distribution of species within the marsh. On the other hand, the resistance produced by the plants can shape the flow structure, turbulent intensity, and the wave dissipation over the canopy. Because marsh plants are flexible structures, their reconfiguration modifies the drag felt by the plants and the flow. While several previous studies have considered the flexibility of the stem, few studies have considered the leaf component, which has been shown to contribute the majority of plant resistance. This paper reports a unique dataset that includes laboratory measurements of both the force on an individual plant and the flow structure and wave energy dissipation over a meadow of plants. In the individual plant experiment, the motion of the plant and plant drag, free surface displacement and velocity profile were measured. The individual plant experiments considered both a live marsh plant (Spartina alterniflora) and a mimic consisting of ten leaves attached to a central stem. For the meadow experiment, velocity profiles were measured both upstream and within the meadow, and free surface displacement was measured along the model marsh plant meadow with high spatial and temporal resolution. These experiments used five water depths (covering both submerged and emergent conditions), three wave periods (from long wave to short waves), seven wave heights (from linear to nonlinear waves), six current conditions (including pure current, pure wave, and combined current and waves). In summary, there are 102 individual plant tests and 58 meadow tests. The drag, free surface displacement, and velocity are reported in SMCW.mat file including the raw data, the phase average, and statistic values. The link to the plant motion videos is also provided. This dataset provides high quality measurements that can be used to develop and validate models of plant motion, hydrodynamic drag on individual plants, vegetation-generated turbulence, the evolution of flow structure through a meadow, and the transformation and dissipation of waves over natural salt marshes. The dataset is available from figshare with detailed instructions for reuse (https://doi.org/10.6084/m9.figshare.24117144; Zhang and Nepf, 2023a) [ABSTRACT FROM AUTHOR]

Salt marshes can contribute to coastal protection, but the magnitude of the protection depends on the width of the marsh. The cross‐shore width of the marsh is to a large extent determined by the delicate balance between seaward expansion and landward retreat. The influence of the magnitude of daily occurring mild weather conditions and sediment availability on the variability of salt marsh width has not been systematically assessed. This paper investigates how the magnitude of homogeneous hydrodynamic forcing, combined with sediment availability, affects the biophysical development, and more specifically retreat and expansion of salt marshes. The dynamic extent of the salt marsh is assessed by modeling online‐coupled hydrodynamics, morphodynamics and vegetation growth using the numerical Delft3D‐Flexible Mesh model, and a vegetation growth module. Simulated patterns around the salt marsh edge resembled field observations, as well as the simulated temporal variability of the lateral position of the salt marsh edge. In the model, the salt marsh extended seaward at low wave forcing (0.00 m; 0.05 m), and retreated landward at higher wave forcing (0.10 m; 0.15 m). With increasing physical stress, the salt marsh edge was found at lower elevations, indicating an unhealthy system with a retreating marsh edge due to vegetation mortality, whereas decreasing physical stresses result in a higher salt marsh edge, enabling expansion. This balance suggests the importance of response time of vegetation to physical stress. Yet, the salt marsh forced with higher waves was able to switch from a retreating extent retrogradational to an expansional behavior as sediment supply increased. Key Points: 50‐year biogeomorphological development of salt marshes, forced by waves and suspended sediment, is modeledSeaward extension is observed with low wave forcing, whereas landward retreat is observed with high wave forcingSalt marshes forced with high waves are able to switch from a retreating to an expanding extent, with increasing sediment availability [ABSTRACT FROM AUTHOR]

SUMMARY: To understand distributions of coastal diatoms along Vancouver Island, British Columbia, Canada, this paper describes diatom assemblages observed in 47 surface sediment samples from intertidal environments. One hundred and eighty‐four diatom taxa were identified from five transects crossing tidal flats, salt marshes, and freshwater forests in Tofino, Ucluelet, and Port Alberni. Distributions of the diatom assemblages were consistent with those reported elsewhere in the Pacific Northwest, but a few diatom taxa show different trends in their distributions. For example, one benthic species Denticula subtilis shows widespread distributions along the transect in Tofino. An ordination shown by Detrended Correspondence Analysis (DCA) using a combined dataset indicated overlapped scatter plots of diatom assemblages, suggesting that assemblages with similar species compositions are observed in more than one location. Hierarchical and k‐means clustering analyses using Euclidean distance recognized unique small groups along each transect. Rank abundance curves show different trends for richness and evenness of diatom assemblages among the five transects. [ABSTRACT FROM AUTHOR]

The aim of this paper is to deal with syntaxonomical and ecological characteristics of Tamarix smyrnensis communities developed on both salt marsh and riparian habitats of the Yeşilırmak Delta Plains. The floristic composition of the communities was analysed by Braun-Blanquet method and the effect of edaphic parameters on the communities were determined using ordination techniques (CCA). The habitat types were identified according to the European Nature Information System (EUNIS) habitat coding list. Junco acuti-Tamaricetum smyrnensis ass. nov. developed on salt marshes and belonging to the alliance of Tamaricion tetragynae, and Tamaricetum tetrandrae-smyrnensis ass. nov. developed on meander banks/river island (eyot) and belonging to the alliance of Rubo sancti—Nerion oleandri distributed under influence of electrical conductivity (EC) of soil. Additionally, it was observed that both associations belonged to subunits of Mediterraneo-Macaronesian tamarisk thickets according to EUNIS. [ABSTRACT FROM AUTHOR]

This paper provides new insights into the geochemical cycling of rare earth elements (REEs) in acid sulfate soils developed on salt marsh sediments of the Huelva estuary (Spain) as a result of sulfide mineral oxidation in abandoned ore stockpiles. The study was aimed at determining the REE abundance, fractionation pattern and mineralogical control of the dispersal and retention of REEs in the soil system. Forty-one samples were collected at 13 core sampling sites along two transects extending across the degraded marshland, and they were subjected to XRD, ESEM-EDS and ICP-MS analyses. Measurements revealed that the soil receiving acid discharges has relatively high concentrations of SREEs (174.77 ± 19.77 mg kg-1) compared to local baseline concentrations. Shale-normalized REE patterns are generally flat, but a slight middle REE (MREE) enrichment is consistently apparent in all soil samples, involving relatively low LaN/GdN ratios (0.83 ± 0.08) and GdN/LuN ratios up to 1.42. The convex-upward REE pattern supports the possibility that iron oxy-hydroxide minerals play an important role in MREE retention through adsorption and co-precipitation mechanisms. Efflorescent sulfate salts left on the topsoil by the evaporation of acid waters show a strong depletion of light REEs (LaN/GdN = 0.16 ± 0.10) and act as a temporary reservoir of labile MREEs and heavy REEs during dry periods. [ABSTRACT FROM AUTHOR]

Research on physical ecosystem engineering—i.e., the structural modification of environments by organisms—has flourished during the last two decades. At present, the importance of physical ecosystem engineers for the biodiversity and the functioning of ecosystems is well recognized by scientists. This Special Issue contains fifteen papers that illustrate the diversity of physical ecosystem engineering processes that occur in the world coastal habitats—from coastal dunes to the shallow subtidal zone. It includes 2 reviews comparing ecosystem engineering attributes and impacts across taxa and 13 case studies that inform our general understanding of the variation in engineering impacts, compound engineering effects, novel engineering interactions, and engineered structural legacies. [ABSTRACT FROM AUTHOR]

This paper presents the first record of fire in Pacific coast salt marshes; the 1993 Green Meadows Fire and the 2013 Camarillo Springs Fire burned an area of Salicornia-dominated salt marsh at Point Mugu, CA. These fires inspire concern about resiliency of ecosystems not adapted to fire, already threatened by sea-level rise (SLR), and under stress from extreme drought. We monitored vegetation percent cover, diversity, and soil organic carbon (SOC) in burned and unburned areas of the salt marsh following the 2013 Camarillo Springs Fire and used remotely sensed Normalized Vegetation Difference Index (NDVI) analysis to verify the in situ data. Two years following the fire, vegetation percent cover in burned areas was significantly lower than in unburned areas, with dominant-species change in recovered areas, and NDVI was lower than pre-fire conditions. Multi-year disturbance, such as fire, presents challenges for salt marsh resilience and dependent species, especially in sites facing multiple stressors. With anticipated higher temperatures, increased aridity, extreme drought, and higher frequency fires becoming a reality for much of the Pacific coast, this study indicates that fire in Salicornia-dominated marshes is a vulnerability that will need to be addressed differently from other grass- or reed-dominated marsh systems. [ABSTRACT FROM AUTHOR]

Background: Ecologists have achieved much progress in the study of mechanisms that maintain species coexistence and diversity. In this paper, we reviewed a wide range of past research related to these topics, focusing on five theoretical bodies: (1) coexistence by niche differentiation, (2) coexistence without niche differentiation, (3) coexistence along environmental stress gradients, (4) coexistence under non-equilibrium versus equilibrium conditions, and (5) modern perspectives. Results: From the review, we identified that there are few models that can be generally and confidently applicable to different ecological systems. This problem arises mainly because most theories have not been substantiated by enough empirical research based on field data to test various coexistence hypotheses at different spatial scales. We also found that little is still known about the mechanisms of species coexistence under harsh environmental conditions. This is because most previous models treat disturbance as a key factor shaping community structure, but they do not explicitly deal with stressful systems with non-lethal conditions. We evaluated the mainstream ideas of niche differentiation and stochasticity for the coexistence of plant species across salt marsh creeks in southwestern Denmark. The results showed that diversity indices, such as Shannon–Wiener diversity, richness, and evenness, decreased with increasing surface elevation and increased with increasing niche overlap and niche breadth. The two niche parameters linearly decreased with increasing elevation. These findings imply a substantial influence of an equalizing mechanism that reduces differences in relative fitness among species in the highly stressful environments of the marsh. We propose that species evenness increases under very harsh conditions if the associated stress is not lethal. Finally, we present a conceptual model of patterns related to the level of environmental stress and niche characteristics along a microhabitat gradient (i.e., surface elevation). Conclusions: The ecology of stressful systems with non-lethal conditions will be increasingly important as ongoing global-scale climate change extends the period of chronic stresses that are not necessarily fatal to inhabiting plants. We recommend that more ecologists continue this line of research. [ABSTRACT FROM AUTHOR]

The open coastlines of the world are dominated by sand dunes and salt marshes. They are the primary areas for human recreation and provide a wide range of frequently overlooked ecosystem services. Their intrinsic ecological significance lies in having unique biological assemblies and supporting a range of ecological processes, such as water filtration and nutrient cycling. In addition, in the coastal zone, these areas link marine and terrestrial systems. The objective of this paper is to check the psammophytic species diversity, conservation status and threat; and also prepare a biological spectrum m in the Costal East Midnapore (CEM) district's sand dune and salt marsh areas. A part of floristic inventories in the CEM, various field trips in different season were carried out, quadrate method is done to examine the ecological impact and richness. Specimens were collected, prepared voucher specimen and enlisted according APG IV classification system to prepare biological spectrum. CEM vegetation was diverse and composed of 162 species of 132 genera distributed among 52 families of 28 orders according to APG IV classification, of which 37 species were exotics. Fabales (19.14%) and Fabaceae (19.14%) were the dominant order and family. Biological spectrum shows the study area was classified as "thero-chamaephytic" type of phytoclimate. Mesophyll (24.07%) and lanceolate as well as oblong (19.14%) were found to be high in the leaf size spectrum and lamina. The area of study was highly ecotonal potential and fairly undisturbed. This study is useful in comparing and contrasting the adjacent natural vegetation along the gradients of the environment; and recommends effective long-term conservation and better management of the coastal area. [ABSTRACT FROM AUTHOR]

Abstract Flood risks are increasing worldwide due to climate change and ongoing economic and demographic development in coastal areas. Salt marshes can function as vegetated foreshores that reduce wave loads on coastal structures such as dikes and dams, thereby mitigating current and future flood risk. This paper aims to quantify long-term (100 years) flood risk reduction by salt marshes. Dike-foreshore configurations are assessed by coupled calculations of wave energy dissipation over the foreshore, sediment accretion under sea level rise, the probability of dike failure, and life-cycle costs. Rising sea levels lead to higher storm waves, and increasing probabilities of dike failure by wave overtopping. This study shows that marsh elevation change due to sediment accretion mitigates the increase in wave height, thereby elongating the lifetime of a dike-foreshore system. Further, different human interventions on foreshores are assessed in this paper: realization of a vegetated foreshore via nourishment, addition of a detached earthen breakwater, addition of an unnaturally high zone, or foreshore build-up by application of brushwood dams that enhance sediment accretion. The performance of these strategies is compared to dike heightening for the physical boundary conditions at an exposed dike along the Dutch Wadden Sea. Cost-effectiveness depends on three main factors. First, wave energy dissipation, which is lower for salt marshes with a natural elevation in the intertidal zone, when compared to foreshores with a high zone or detached breakwater. Second, required costs for construction and maintenance. Continuous maintenance costs and delayed effects on flood risk make sheltering structures less attractive from a flood risk perspective. Third, economic value of the protected area, where foreshores are particularly cost-effective for low economic value. Concluding, life-cycle cost analysis demonstrates that, within certain limits, foreshore construction can be more cost-effective than dike heightening. Highlights • Long-term (100 years) cost-effectiveness of vegetated foreshores assessed. • Cost-effectiveness of strategies depends on the economic damage after dike failure. • Sediment accretion on salt marshes elongates the lifetime of flood defenses. • High zones or breakwaters on marshes increase effects on flood risk against low costs. [ABSTRACT FROM AUTHOR]

The present paper aims to discuss the functional and ecophysiological traits of two abundant succulent halophytes in Mediterranean salt marsh systems, considering two ecotypes differing on their tidal exposure. In Halimione portulacoides the higher root/shoot (R/S) biomass ratio verified in low inundation frequency (LF) marshes, as compared with that in high inundation frequency (HF), indicates an optimal partitioning strategy, inducing differential allocation patterns along with varying environmental factors. Conversely, Sarcocornia perennis appear to have an isometric allocation strategy, based on intrinsic biomass allocation mechanisms independent from the surrounding environmental conditions. Similarly, the photosynthetic traits appear to reflect the intrinsic ecology of the species. Sarcocornia perennis habitat adaptation to HF conditions is clearly revealed by its high photosynthetic efficiency under HF conditions. On the other hand, the cosmopolitan H. portulacoides shows no differences between ecotypes, in which concerns this trait, mostly due to the high carotenoid content of the HF ecotype, which allows this specie to counteract the stress generated during submersion. Additionally, anti-oxidant enzymatic activities revealed that S. perennis presents a high degree of stress tolerance under HF conditions, while H. portulacoides is highly adapted to LF conditions. These functional (biomass-related) and physiological traits determine the optimal habitats for H. portulacoides and S. perennis. While H. portulacoides optimal biomass partitioning, along with its efficient anti-oxidant defence system, makes this species fitter to LF conditions, S. perennis isometric allocation strategy, along with a higher photosynthetic efficiency under frequent flooding conditions, provides this species the mechanisms to efficiently colonize the intertidal habitat. [ABSTRACT FROM AUTHOR]

Vegetated foreshores adjacent to engineered structures (so-called hybrid flood defenses), are considered to have high potential in reducing flood risk, even in the face of sea level rise and increasing storminess. However, foreshores such as salt marshes and mangrove forests are generally characterized by relatively strong temporal and spatial variations in geometry and vegetation characteristics (e.g., stem height and density), which causes uncertainties with regards to their protective value under extreme storm conditions. Currently, no method is available to assess the failure probability of a hybrid flood defense, taking into account the aforementioned uncertainties. This paper presents a method to determine the failure probability of a hybrid flood defense, integrating models and stochastic parameters that describe dike failure and wave propagation over a vegetated foreshore. Two dike failure mechanisms are considered: failure due to (i) wave overtopping and (ii) wave impact on revetments. Results show that vegetated foreshores cause a reduction in failure probability for both mechanisms. This effect is more pronounced for wave impact on revetments than for wave overtopping, since revetment failure occurs at relatively low water levels. The relevance of different uncertainties depends on the protection level and associated dike height and strength. For relatively low dikes (i.e., low protection levels), vegetation remains stable in design conditions, and plays an important role in reducing wave loads. In case of higher protection levels, hence for more robust dikes, vegetation is less important than foreshore geometry, because of expected stem breakage of the vegetation under these more extreme conditions. The integrated analysis of uncertainties in hydraulic loads, dike geometry and foreshore characteristics in this paper enables the comparison between nature-based flood defenses and traditionally engineered solutions, and allows coastal engineers to design hybrid flood defenses worldwide. [ABSTRACT FROM AUTHOR]

Salt marsh ecology classification is difficult using traditional coarse resolution remote sensing techniques. Salt marshes exhibit a spatial pattern of vegetation zonation that are visually identifiable using imagery that has an improved 0.04 meter per pixel resolution. This project applies high resolution unmanned aerial system (UAS) imagery to aid in multi-temporal classification of our study area (Horseneck Beach) in Westport, Massachusetts, USA. We flew a DJI Phantom Pro 3 at low- and high-tide to capture effects the changing tide has on vegetation in an effort to predict effects of the rising sea level on saline plant species. We implement an open source software workflow using OpenDroneMap and the Semi-Automatic Classification Plugin for QGIS to create the necessary orthomosaics and to conduct vegetation classification required of this project. We compare land cover classifications using one-time-point RGB imagery to a multi-time-point (low tide, high tide) RGB image stack to investigate whether the multi-time point stack improves land cover classification accuracy. We find it does. More generally, this paper provides a model for others wishing to use low-cost UAS equipment carrying a simple low-cost RGB camera, and free and open source for geospatial (FOSS4G) tools, to develop multi-band image stacks to improve land cover classification accuracy. Further, we provide some reflections and technical notes on our experience. The approach we present here could be extended to include other image layers that UAS can provide when equipped with other sensors, such as multi-spectral (e.g., NIR, thermal), or by adding another band with photogrammetry-produced digital elevation data. [ABSTRACT FROM AUTHOR]

Saltmarsh sparrows (Ammospiza caudacuta) and seaside sparrows (A. maritima) are species of conservation concern primarily due to global sea-level rise and habitat degradation. Environmental mercury (Hg) contamination may present additional threats to their reproductive success and survival. To assess site-specific total mercury (THg) exposure and identify environmental correlates of THg detection, we sampled blood from adult male saltmarsh and seaside sparrows at 27 sites between Maine and Virginia, USA. The mean THg concentration (±1 SD) throughout the entire sampling range was 0.531 ± 0.287 µg/g wet weight (ww) for saltmarsh sparrows and 0.442 ± 0.316 µg/g ww for seaside sparrows. Individual THg concentrations ranged from 0.135–1.420 µg/g ww for saltmarsh sparrows and 0.153–1.530 µg/g ww for seaside sparrows. Model averaging from a suite of linear mixed models showed that saltmarsh sparrows averaged 20.1% higher blood THg concentrations than seaside sparrows, potentially due to differences in diet or foraging behavior. We found no evidence for a relationship between sparrow THg concentrations and land cover surrounding sampled marshes or average precipitation-based Hg deposition. Overall, our results suggest considerable, unexplained variation in tidal marsh sparrow blood THg concentrations over their co-occurring breeding ranges. [ABSTRACT FROM AUTHOR]

Biodiversity plays important roles in nature's contributions to people (i.e., ecosystem services), but the critical details of how biodiversity contributes are challenging to determine. Efforts to identify the components of an ecosystem that provide services have improved our understanding of which species, functional groups, population, or habitats directly provide services. However, species do not exist in isolation and considerably less is known about how species indirectly influence ecosystem services through interacting with those species directly providing services. This uncertainty is even greater when considering that species interact in complex networks. As such, detailed analyses of species interdependencies are rarely included in ecosystem services assessments or conservation decisions. To date, most studies on food webs and on ecosystem services have developed largely in parallel for many services, but these fields and data are ripe for empirical integration. To further this integration, we compiled data sets that linked three existing ecological networks to seven ecosystem functions and services: wave attenuation, shoreline stabilization, carbon sequestration, water filtration, fisheries, birdwatching, and waterfowl hunting. We leveraged high‐resolution ecological interaction network data sets from three coastal salt marsh ecosystems including detailed species information (e.g., consumer strategy, body size, biomass) on several hundred species from Carpinteria Salt Marsh in California, USA, and for Estero de Punta Banda and Bahia Falsa in Baja, Mexico from Hechinger et al. (2011). Through an extensive literature synthesis and use of citizen science data, we identified which species in the Hechinger et al. (2011) data provided each ecosystem services directly. We augmented the Hechinger et al. (2011) data published in Ecology, particularly the link (or edge) list to include species—service links to indicate a species providing a service, in which species are listed as "Resources" and services are listed as "Consumers." Connecting these data to the previously published ecological networks with species interactions (i.e., trophic, parasitism) formed a topological network with species and service nodes. We also provided a protocol for assigning services to ecological networks that can be used in other ecosystems. This data set provides a step toward advancing the knowledge of important supporting species for ecosystem services and to developing new ecological network methods for ecosystem services. There are no copyright restrictions; please cite this data paper when the data are used in publications. [ABSTRACT FROM AUTHOR]

Knight, J.; Eslami-Andargoli, L.; Dale, P., and Fry, B., 2017. State changes in tropical intertidal systems: A palaeo-ecological approach. The aim was to review ecosystem state changes and the role of palaeo-ecological tools with application to intertidal subtropical and tropical intertidal wetlands. These systems are especially vulnerable to stress from sea-level change, climate change, and development activities. Responses to stress can lead to significant state changes with the system passing thresholds, potentially beyond recovery. Indicators of state changes and approaching tipping points include a critical slowing down following perturbation signalled by, for example, slowing recovery rates, increased attribute variance, and changed skewness. To identify such changes, data are needed for the relevant variables such as vegetation, sea level, and sediment processes so as to observe the indicative changes and their timing. Because changes may be relatively slow in ecological terms, very long-term data are needed to inform management about future likely states or thresholds so that mitigation or adaptation can be planned. One approach is to use palaeo-ecological data. These data are relatively scarce in tropical intertidal systems. This paper reviews a range of palaeo-indicators. These include state indicators (pollen, foraminifera, and diatoms), stable isotope analysis, and stratigraphy and temporal indicators involving sediment dating. Each is potentially useful, although there are uncertainties related to, for example, the redistribution organic matter in sediment cores. In conclusion, it is recommended that integrating or combining several indicators can assist in triangulating results, thereby increasing confidence in their interpretation. It is also suggested that data, if available, can be retrofitted to assess at least some of the state change indicators, such as data variance and skewness. [ABSTRACT FROM AUTHOR]

Abstract Background The study of soil organic carbon characteristics and its relationship with soil environment and vegetation types is of great significance to the evaluation of soil carbon sink provided by inland salt marshes. This paper reports the characteristics of soil organic carbon fractions in 0–50 cm soil layers at four vegetation communities of the Qinwangchuan salt marsh. Results (1) The soil organic carbon content of Phragmites australis community (9.60 ± 0.32 g/kg) was found to be higher than that of Salicornia europae (7.75 ± 0.18 g/kg) and Tamarix ramosissima (4.96 ± 0.18 g/kg) and Suaeda corniculata community (4.55 ± 0.11 g/kg). (2) The soil dissolved organic carbon, particulate organic carbon and soil microbial biomass carbon in 0–50 cm soil layer of Phragmites australis community were higher, which were 0.46 ± 0.01 g/kg, 2.81 ± 0.06 g/kg and 0.31 ± 0.01 g/kg, respectively. (3) Soil organic carbon was positively correlated with dissolved organic carbon, particulate organic carbon, and microbial biomass carbon, and negatively correlated with easily oxidized organic carbon. (4) Above-ground biomass has a strong direct positive effect on soil organic carbon, total nitrogen and pH have a strong direct positive effect on microbial biomass carbon content, pH and average density have a strong direct negative effect on easily oxidized organic carbon, and particulate organic carbon. Conclusions The interaction between plant community characteristics and soil factors is an important driving factor for soil organic carbon accumulation in inland salt marshes.

The Ministry for Climate Protection, Agriculture, Rural Areas and the Environment in Mecklenburg-Vorpommern prepares a strategy for insect conservation. One module within the program "More respect for the insect" aimed to compare sites with completed or ongoing conservation measures with conventionally managed reference sites in order to obtain data-based recommendations for future actions. Study sites comprised organically managed arable land (vs. conventionally managed fields), stripes of grassland fallows (vs. used grassland), re-wetted and/ or abandoned peatland meadows (vs. managed grassland on drained peatland), restoration of salt marshes by relocation of dikes (vs. diked grassland) and initial stages of xerothermic grassland as a substitute for management in protected areas (vs. later succession stages). The localities were in the surroundings of Greifswald, Anklam and Pasewalk. Arthropods were sampled with pitfall traps according to the guidelines for the nationwide insect monitoring which applied at that time. At each plot six pitfalls were positioned in linear transects with Renner solution as preservative. Carabid beetles and spiders were identified to species level and included in the assessment. Concerning spiders, a total of 22902 specimens (20765 adults) from 189 species were recorded. The study provided the first records of Porrhomma campbelli, Prinerigone vagans and Robertus heydemanni in Mecklenburg-Vorpommern. Further six species are critically endangered (category 1) according to the latest version of the Red list of spiders in Mecklenburg-Vorpommern: Diplocephalus dentatus, Euryopis laeta, Micaria dives, Pellenes nigrociliatus, Psammitis sabulosus, Silometopus ambiguus. [ABSTRACT FROM AUTHOR]

Whitehead, S.J.; Yeager, K.M.; Feagin, R.A.; Huff, T.P.; Paine, J.G.; Schindler, K.S., and Dixon, T.S., 2024. Growth fault–induced effects on tidal marsh surficial processes and landscape conversion in the Slop Bowl, Brazoria National Wildlife Refuge, Texas. Journal of Coastal Research, 40(1), 64–79. Charlotte (North Carolina), ISSN 0749-0208. The Slop Bowl marsh, located in the Brazoria National Wildlife Refuge on the Texas coast, is an anthropogenically influenced tidal marsh setting that has experienced rapid rates of landscape conversion and loss over the last ∼70 years. This tidal marsh has been affected by recently active faults and several hydrologic barriers (roads, pipeline channels, and active hydrocarbon-extraction well pads). Geophysical field methods and sedimentological analyses were conducted to better understand the effects of these developments on marsh surficial processes. Lithostratigraphy, shallow geophysical data, GPS surveys, radionuclide dating, and organic matter analyses all exhibited influences connected to growth-fault motion. The location and activity of a major growth fault were identified as contributing to subsidence on the downthrown fault block and causing vertical displacement of the marsh surface. Fault motion, in conjunction with the construction of roads, has disrupted the natural hydrologic pathways that once existed. Their combined effects resulted in transition of the land cover over the past several decades from a saline coastal prairie to a tidal marsh–dominant landscape, with continued future submergence anticipated. As the natural laboratory of the Slop Bowl demonstrates, anthropogenic development, neotectonics, and hydrocarbon extraction can have outsized effects on sedimentation processes, with implications for the long-term sustainability of coastal wetland environments in the northern Gulf of Mexico. [ABSTRACT FROM AUTHOR]

In the United States (US), salt marshes are especially vulnerable to the effects of projected sea level rise, increased storm frequency, and climatic changes. Sentinel-2 data offer the opportunity to observe the land surface at high spatial resolutions (10 m). The Sentinel-2 data, encompassing Cumberland Island National Seashore, Fort Pulaski National Monument, and Canaveral National Seashore, were analyzed to identify temporal changes in salt marsh presence from 2016 to 2020. ENVI-derived unsupervised and supervised classification algorithms were applied to determine the most appropriate procedure to measure distant areas of salt marsh increases and decreases. The Normalized Difference Vegetation Index (NDVI) was applied to describe the varied vegetation biomass spatially. The results from this approach indicate that the ENVI-derived maximum likelihood classification provides a statistical distribution and calculation of the probability (>90%) that the given pixels represented both water and salt marsh environments. The salt marshes captured by the maximum likelihood classification indicated an overall decrease in salt marsh area presence. The NDVI results displayed how the varied vegetation biomass was analogous to the occurrence of salt marsh changes. Areas representing the lowest NDVI values (−0.1 to 0.1) corresponded to bare soil areas where a salt marsh decrease was detected. [ABSTRACT FROM AUTHOR]