Search

The Many-colored Rush Tyrant (Tachuris rubrigastra) and Wren-like Rushbird (Phleocryptes melanops) are birds that inhabit the subtropical salt marshes of Brazil, a newly recognized ecosystem of tidal marshes. We studied the habitat selection of these species in the subtropical salt marshes, characterizing the vegetation types where the species did and did not occur in the same habitats. The species occurred in a total of four very simplified vegetation types, characterized by the dominance of one or two plant species, including Schoenoplectus californicus, Crinum americanum, Cladium jamaicense, and Typha domingensis. We found that the habitats selected by the birds have very specific phytophysiognomic characteristics related to vegetation height and density. Moreover, the lower altitudes of certain areas of occurrence implies longer and higher flooding during periods of high tides; thus, the greater height of the vegetation maintains an above-water-level foraging and protective area for the birds. The fact that subtropical salt marshes are a transitional ecosystem suggests the possibility of rapid changes in plant succession or an intensification of the tropicalization process with mangrove expansion, which could eliminate habitat characteristics that are crucial to the survival of these two bird species in the subtropical salt marshes of Brazil. [ABSTRACT FROM AUTHOR]

Salt marshes are highly dynamic and biologically diverse ecosystems that serve as natural habitats for numerous salt-tolerant plants (halophytes). We investigated the bacterial communities associated with the roots and leaves of plants growing in the coastal salt marshes of the Bayfront Beach, located in Mobile, Alabama, United States. We compared external (epiphytic) and internal (endophytic) communities of both leaf and root plant organs. Using 16S rDNA amplicon sequencing methods, we identified 10 bacterial phyla and 59 different amplicon sequence variants (ASVs) at the genus level. Bacterial strains belonging to the phyla Proteobacteria, Bacteroidetes, and Firmicutes were highly abundant in both leaf and root samples. At the genus level, sequences of the genus Pseudomonas were common across all four sample types, with the highest abundance found in the leaf endophytic community. Additionally, Pantoea was found to be dominant in leaf tissue compared to roots. Our study revealed that plant habitat (internal vs. external for leaves and roots) was a determinant of the bacterial community structure. Co-occurrence network analyses enabled us to discern the intricate characteristics of bacterial taxa. Our network analysis revealed varied levels of ASV complexity in the epiphytic networks of roots and leaves compared to the endophytic networks. Overall, this study advances our understanding of the intricate composition of the bacterial microbiota in habitats (epiphytic and endophytic) and organs (leaf and root) of coastal salt marsh plants and suggests that plants might recruit habitat- and organ-specific bacteria to enhance their tolerance to salt stress. [ABSTRACT FROM AUTHOR]

Coastal vegetated ecosystems including mangroves, seagrasses, and salt marshes are often shaped by positive plant–environment feedbacks. Plants improve their own living conditions with increasing patch size and density by attenuating hydrodynamics and stabilizing sediments. As these habitat modifications are critical for survival and growth, the positive density‐dependent nature of these feedbacks can lead to establishment thresholds for young plants in absence of mature conspecifics. Although feedback strength is known to depend on hydrodynamic exposure and plant traits (e.g. stiff versus flexible stems), it remains unclear how 1) opposing morphological plant traits affect establishment in contrasting environments, and 2) whether trait plasticity influences establishment success. Here, we investigate this by transplanting two tidal species with opposing growing strategies – Spartina anglica forms tussocks of stiff stems while Zostera noltii forms patches of stress‐avoiding flexible shoots – from two different donor sites in eight experimental locations. Results show that the survival and growth of both species was most successful at field locations with diverging environmental characteristics, while overall survival was highest for Z. noltii. Mainly, S. anglica survival was highest at locations with high organic matter and silt content and higher elevation relative to the tidal amplitude. In contrast, Z. noltii survival was highest at locations with larger grainsize and lower relative elevations. Furthermore, despite initial differences in plant traits between the two donor sites of Z. noltii, we found no effects of donor origin. Contrastingly, we found a significant effect of donor origin on S. anglica growth, even though transplants from the two donor sites showed no initial trait differences. Collectively, these results suggest that the stress‐tolerance strategy of S. anglica hampers establishment in exposed conditions, whereas the stress‐avoiding Z. noltii appears to be more susceptible to stress from desiccation and silty sediments. [ABSTRACT FROM AUTHOR]

As global climate change alters the magnitude and rates of environmental stressors, predicting the extent of ecosystem degradation driven by these rapidly changing conditions becomes increasingly urgent. At the landscape scale, disturbances and stressors can increase spatial variability and heterogeneity — indicators that can serve as potential early warnings of declining ecosystem resilience. Increased spatial variability in salt marshes at the landscape scale has been used to quantify the propagation of ponding in salt marsh interiors, but ponding at the landscape scale follows a state change rather than predicts it. Here, we suggest a novel application of commonly collected surface elevation table (SET) data and explore millimeter-scale marsh surface microtopography as a potential early indicator of ecosystem transition. We find an increase in spatial variability using multiple metrics of microtopographic heterogeneity in vulnerable salt marsh communities across the North American Atlantic seaboard. Increasing microtopographic heterogeneity in vulnerable salt marshes mirrored increasing trends in variance when a tipping point is approached in other alternative stable state systems — indicating that early warning signals of marsh drowning and ecosystem transition are observable at small-spatial scales prior to runaway ecosystem degradation. Congruence between traditional and novel metrics of marsh vulnerability suggests that microtopographic metrics can be used to identify hidden vulnerability before widespread marsh degradation. This novel analysis can be easily applied to existing SET records expanding the traditional focus on vertical change to additionally encapsulate lateral processes. [ABSTRACT FROM AUTHOR]

Species invasion in salt marsh wetlands is known to disturb the balance of biotic and abiotic ecosystems (e.g., changing material exchange cycles and community structure). However, its influence on the morphological evolution of salt marshes is not yet understood in depth. This study investigates the long-term temporal and spatial distributions of an invasive plant (Spartina alterniflora) and its morphological characteristics in the Yangtze Estuary by remote sensing imagery interpretation, tidal creek extraction, regional statistical analysis, and proximity analysis. The invaded site shows an area of Spartina alterniflora with a 35-fold increase from the start to the end of its initiation phase; it is the second biggest species in the study area. It is found that species invasion not only limited the expansion of native pioneer vegetation but also changed bio-geomorphic feedback loops. With the influence of plant invasion, median tidal creek lengths decreased and the median tidal creek sinuosity ratio remained stable, between 1.06 and 1.07 in the subarea. The method used here is adaptable to other salt marshes. The findings from this study can provide practical guidance for the restoration of native salt marshes in the estuary and thus control the spread of invasive species. [ABSTRACT FROM AUTHOR]

Microscopic eukaryotes are important components of coastal wetland ecosystems. The goal of this study was to investigate the diversity of microeukaryotes in the tidal pools of a New Jersey salt marsh and to compare the assemblages of natural and artificial pools excavated for controlling mosquito populations. We evaluated microeukaryotic assemblages using the amplicon sequencing of 18S and rbcL DNA markers and the microscopic identification of diatoms in water and sediment samples. 18S unique amplicon sequence variants (ASV) representing ciliates, dinoflagellates, diatoms, and cercozoans were the most diverse, while the reads of dinoflagellates, diatoms, ciliates, and nematodes were the most abundant. The dominant ASVs were attributed to organisms that are characteristic of coastal plankton and sediments or those known for their resistance to salinity, desiccation, hypoxia, and UV stress. The sediment assemblages were more diverse compared to those from the water column and contained a larger portion of ASVs that were not assigned to any low-rank taxa, reflecting the current gaps in understanding the diversity of microeukaryotes. Most taxonomic groups were significantly different in their abundance and composition between natural and artificial pools. Dinoflagellates, haptophytes, chrysophytes, pelagophytes, and raphidophytes—the groups that include a large proportion of mixotrophic taxa and species known for forming harmful algal blooms—were more abundant in the artificial than in the natural pools. Fungi, labyrinthulomycetes, and peronosporomycetes were also more abundant in artificial pools, which may be related to organic matter enrichment. Diatoms and foraminifera showed an opposite trend of higher abundance in natural pools. [ABSTRACT FROM AUTHOR]

Sea level rise and storm surges drive coastal forest retreat and salt marsh expansion. Both salinization and flooding control ecological zonation and ecosystem transition in coastal areas. Hydrological variables, if coupled with ecological surveys, can explain the different stages of coastal forest retreat and marsh encroachment. In this research, long‐term data of a host of hydrological variables collected along transects from marsh to inner forest were analyzed. Linear discriminant analysis (LDA) was used to identify the primary hydrological variables responsible for the forest‐marsh gradient and their seasonal patterns. Water content (WC) in the soil (WC) and groundwater electrical conductivity (EC) were found to be the main variables responsible for the hydrological differences among the sites. Higher values of WC and EC were found in the low‐forest area near the salt marsh, with hydrological differences between forest levels reflected in ecological community structure. In particular, some sites were characterized by high EC while others by high WC values, suggesting significant spatial variations within hundreds of meters. The forested area, relatively flat in elevation, was characterized by limited hydraulic gradients and consequently lateral discharges. These characteristics made the role of groundwater level negligible in driving the hydrological clustering. Seasonal LDA data suggest that the sites are hydrologically different during winter (higher distance among clusters of variables) and similar during summer (low distance among clusters). In the study area, higher rainfall occurs during summer, decreasing groundwater EC in areas characterized by low canopy cover (dying forest). Rainfall moved low forest sites closer to the pristine high forest in the LDA analysis. During storm surge events, the distance between clusters decreased, indicating uniform salinization and flooding across the forest. Therefore, we conclude that ecological zonation in a coastal forest is reflected in seasonal hydrological differences in the absence of storm surges. Storm surges do not produce contrasting hydrological conditions and might not be responsible for ecological differences in the short‐term. On the contrary, differences in hydrological recovery are responsible for forest zonation. An additional analysis carried out using a binary Marsh‐Healthy forest LDA classifier indicates when each site switches from a forest hydrological state to a salt‐marsh hydrological state. Our results are useful for long‐term predictions of the ecological evolution of the forest–salt marsh ecotone. Key Points: Linear discriminant analysis was used to cluster hydrological variables in a coastal forest affected by sea level rise (SLR) and storm surgesHydrological clustering was related to ecological characteristicsStorm surges tend to homogenize the hydrological variables across the study site, while in winter spatial gradients are present [ABSTRACT FROM AUTHOR]

Globally, blue carbon ecosystems, including salt marsh, mangroves, and seagrasses, and the associated ecosystem services they provide, have declined substantially. In response, ecosystem restoration has recently increased but the scale and urgency of these activities has been limited by the lack of economic drivers. Herein, a multidisciplinary approach is presented that links hydrologic restoration with ecologic outputs to highlight the economic potential for commercial fisheries that could arise from restoring a drained floodplain. Initially, stable isotope models are used to predict the return of Eastern school prawn (approximately 300 kg yr−1 ha−1). Hydrologic models are then applied to determine the area of salt marshes and mangroves (over 2,000 ha) that could be potentially restored via tidal introduction. Together, these results indicate that ecological restoration in this region could contribute an annual benefit of approximately 230 tons of additional Eastern school prawn harvest, which could be valued at $3.1 ± 1.3 million AUD to commercial fisheries. This would represent a growth of nearly 50% from current annual harvest in the state. Given that this assessment excludes other values that would be gained, such as other species of fisheries value, carbon sequestration, biodiversity, and flood control, it represents a conservative financial estimate. Overall, this analysis highlights the scale of fisheries co‐benefits from tidal restoration projects, and how business cases for large‐scale blue carbon ecosystem restoration projects could be developed using multidisciplinary approaches. [ABSTRACT FROM AUTHOR]

Non-native plants can significantly affect biodiversity and ecological functions of local ecosystems. The effects of Kandelia obovata introduction and Spartina alterniflora invasion on benthic bacterial communities, predicted ecological functions and interactions between macrobenthos and microorganisms were studied. High-throughput sequencing of the 16S rRNA gene was used to investigate the bacterial communities in sediments covered by S. alterniflora and K. obovata at different stand ages. Bacterial communities showed obvious spatial variation. With increasing in planting age, K. obovate sediments were occupied by higher proportions of bacteria involved in degradation of organic carbon compounds, including various sulfate reduction bacteria, Bacteroidetes, Alphaproteobacteria, and pathogenic bacteria Vibrio , while the relative abundances of Actinomatinales and Sulfurovum were more abundant in younger K. obovate sites. Compared to adjacent mudflat, higher abundances of sulfate reduction bacteria were observed in S. alterniflora. This study indicated that K. obovata introduction had greater effects on bacterial communities, and sediment pH, grain size, soil organic carbon, total nitrogen and total phosphorus contents were main environmental factors affecting variation in bacterial communities. Tax4fun analysis further suggested that higher potentials of nitrogen fixation and dissimilatory sulfate reduction were observed after K. obovata restoration and S. alterniflora invasion. There were significant correlations between macrobenthos and bacterial communities, especially variations in relative abundance of infaunas and herbivores after K. obovata introduction and S. alterniflora invasion, which significantly affected bacterial communities and potentials involved in nitrogen cycling. The present study provided valuable information in scientific assessing the impacts of non-native plant disturbance on local ecosystems. [ABSTRACT FROM AUTHOR]

Three years of study (2016-2019) of endangered habitats of inland salt marshes and salt steppes have yielded several interesting and novel data about the araneofauna of Slovakia. Ground-active spider communities were studied at nine localities belonging to Natura 2000 sites in the Pannonian region. A total of 220 species were recorded, of which 28 species are listed in the Slovak Red List as threatened and 18 species as potentially threatened. The other 11 documented rare species were recorded only in the last decade and are known from only one or a few localities. During the first part of the study, six first records for our fauna from salt marshes (already published) were revealed. Moreover, the continuation of the research brought other new findings for the Slovakian araneofauna Pardosa tenuipes (Lycosidae), Dactylopisthes digiticeps (Linyphiidae) and Ozyptila sanctuaria (Thomisidae). Their characteristic features, photos of the habitus and genitalia, notes on their phenology, habitat, an overview of the currently known distribution, and the dominant species of spider assemblages are presented. [ABSTRACT FROM AUTHOR]

Dead plant biomass from foundation plant species is fundamental for the survival of coastal salt marshes because dead biomass aids in the vertical accretion of the ecosystem. Fungi regulate the decomposition of dead biomass, and thus play an essential role for marsh survival. Despite their importance, little is known about the compositional and functional changes of fungal communities in plant matter throughout senescence and litter decomposition. Here, we analyzed how fungal communities and their functionality change in the foundation plant species Spartina patens, which builds vast amounts of dead plant biomass (thatch) on the soil surface. We analyzed the chemical and fungal properties of live biomass, standing dead biomass (dead biomass shortly after senescence), upper thatch (top layer of litter on the soil surface), and lower thatch (bottom layer of litter on the soil surface) during September and November of 2021. We found that the chemical and fungal properties of different S. patens biomass types followed a predictable litter decomposition pattern. Notably, live biomass, standing dead biomass, upper thatch, and lower thatch all hosted unique fungal communities and litter chemistry. Functional groups present in live biomass (pathogens, epiphytes, and mycoparasites) were lost during senescence and later replaced by diverse saprotrophs. The abundance of lignocellulose saprotrophs increased throughout decomposition, with the highest abundance occurring in lower thatch. These results suggest a predictable succession of fungal communities through the senescence and decomposition of the foundation species S. patens. Our study highlights the diversity of fungal communities in a disappearing foundation species. [ABSTRACT FROM AUTHOR]

Sulfur-cycling microbial communities in salt marsh rhizosphere sediments mediate a recycling and detoxification system central to plant productivity. Despite the importance of sulfur-cycling microbes, their biogeographic, phylogenetic, and functional diversity remain poorly understood. Here, we use metagenomic data sets from Massachusetts (MA) and Alabama (AL) salt marshes to examine the distribution and genomic diversity of sulfur-cycling plant-associated microbes. Samples were collected from sediments under Sporobolus alterniflorus and Sporobolus pumilus in separate MA vegetation zones, and under S. alterniflorus and Juncus roemerianus co-occuring in AL. We grouped metagenomic data by plant species and site and identified 38 MAGs that included pathways for sulfate reduction or sulfur oxidation. Phylogenetic analyses indicated that 29 of the 38 were affiliated with uncultivated lineages. We showed differentiation in the distribution of MAGs between AL and MA, between S. alt erniflorus and S. pumilus vegetation zones in MA, but no differentiation between S. alt erniflorus and J. roemerianus in AL. Pangenomic analyses of eight ubiquitous MAGs also detected site- and vegetation-specific genomic features, including varied sulfur-cycling operons, carbon fixation pathways, fixed single-nucleotide variants, and active diversity-generating retroelements. This genetic diversity, detected at multiple scales, suggests evolutionary relationships affected by distance and local environment, and demonstrates differential microbial capacities for sulfur and carbon cycling in salt marsh sediments. IMPORTANCE Salt marshes are known for their significant carbon storage capacity, and sulfur cycling is closely linked with the ecosystem-scale carbon cycling in these ecosystems. Sulfate reducers are key for the decomposition of organic matter, and sulfur oxidizers remove toxic sulfide, supporting the productivity of marsh plants. To date, the complexity of coastal environments, heterogeneity of the rhizosphere, high microbial diversity, and uncultured majority hindered our understanding of the genomic diversity of sulfur-cycling microbes in salt marshes. Here, we use comparative genomics to overcome these challenges and provide an in-depth characterization of sulfur-cycling microbial diversity in salt marshes. We characterize communities across distinct sites and plant species and uncover extensive genomic diversity at the taxon level and specific genomic features present in MAGs affiliated with uncultivated sulfur-cycling lineages. Our work provides insights into the partnerships in salt marshes and a roadmap for multiscale analyses of diversity in complex biological systems. [ABSTRACT FROM AUTHOR]

Identifying ecosystems with high carbon uptake is essential to establish protection policies that mitigate the increase of greenhouse gasses due to human activities. Although salt marshes cover small continental areas, they assimilate atmospheric CO2 more efficiently than other terrestrial ecosystems. An atmospheric CO2 flux data set measured with the Eddy Covariance (EC) technique allowed us to calculate the net ecosystem exchange (NEE) in a South American salt marsh. The data gaps usually produced by EC were filled in with parametric models that estimate Ecosystem Respiration (Reco) and Gross Primary Production (GPP). Their performance was tested against the Look-Up Table (LUT) and the REddyProc package developed by the Department for Biogeochemical Integration of the Max Planck Institute, Germany. REddyProc and LUT filled the NEE series with greater accuracy. Instead, Reco and GPP models best accounted for seasonal variability at bi-monthly time steps. Regardless of the gap-filling technique, calculations indicated a net CO2 uptake of 5.09 to 6.39 ton ha−1 from May to December 2018, which is 2 to 3 times higher than Northern Hemisphere salt marshes for the same monthly period. Results suggest that these ecosystems play an important role in CO2 mitigation, revealing the importance of their restoration and conservation. [ABSTRACT FROM AUTHOR]

Salt marshes are dynamic, highly productive ecosystems positioned at the interface between terrestrial and marine systems. They are exposed to large quantities of both natural and anthropogenic carbon input, and their diverse sediment-hosted microbial communities play key roles in carbon cycling and remineralization. To better understand the effects of natural and anthropogenic carbon on sediment microbial ecology, several sediment cores were collected from Little Sippewissett Salt Marsh (LSSM) on Cape Cod, MA, USA and incubated with either Spartina alterniflora cordgrass or diesel fuel. Resulting shifts in microbial diversity and activity were assessed via bioorthogonal non-canonical amino acid tagging (BONCAT) combined with fluorescence-activated cell sorting (FACS) and 16S rRNA gene amplicon sequencing. Both Spartina and diesel amendments resulted in initial decreases of microbial diversity as well as clear, community-wide shifts in metabolic activity. Multi-stage degradative frameworks shaped by fermentation were inferred based on anabolically active lineages. In particular, the metabolically versatile Marinifilaceae were prominent under both treatments, as were the sulfate-reducing Desulfovibrionaceae, which may be attributable to their ability to utilize diverse forms of carbon under nutrient limited conditions. By identifying lineages most directly involved in the early stages of carbon processing, we offer potential targets for indicator species to assess ecosystem health and highlight key players for selective promotion of bioremediation or carbon sequestration pathways. [ABSTRACT FROM AUTHOR]

Introduction: Grazing prohibition is an effective management practice to restore salt marsh functioning. However, the effects of grazing exclusion on denitrifying microbial communities and their controlling factors in salt marshes remain unclear. Methods: In this study, we surveyed soil physicochemical properties and aboveand below-ground biomass and using quantitative polymerase chain reaction and Illumina MiSeq high-throughput sequencing technology to determine the relative abundance, composition, and diversity of nitrite reductase nirS- and nirK-type denitrifying bacterial communities associated with grazing prohibition treatments and elevations. Results: The abundance of nirS-type denitrifiers increased with grazing prohibition time, whereas the abundance of nirK-type denitrifiers remained unaltered. Moreover, nirS-type denitrifiers were more abundant and diverse than nirK-type denitrifiers in all treatments. Grazing prohibition significantly altered the operational taxonomic unit richness, abundance-based coverage estimator, and Chao1 indices of the nirS-type denitrifying bacterial communities, whereas it only minimally affected the structure of the nirK-type denitrifying bacterial community. Discussion: The results imply that the nirS community, rather than nirK, should be the first candidate for use as an indicator in the process of salt marsh restoration after grazing prohibition. Substances of concern, total nitrogen, and salinity were the key environmental factors affecting the abundance and community composition of nirS and nirK denitrifiers. The findings of this study provide novel insights into the influence of the length of grazing prohibition and elevation on nirS- and nirK-type denitrifying bacterial community composition in salt marshes. [ABSTRACT FROM AUTHOR]

Context: The area-isolation paradigm of metapopulation theory predicts that larger and more connected patches have a higher probability of occupancy. Although it may be too simplistic for generalist terrestrial mammals, the area-isolation paradigm may be an effective tool for assessing patch-occupancy for habitat specialists. Objectives: We tested predictions of the area-isolation paradigm for the endangered salt marsh harvest mouse (Reithrodontomys raviventris), a habitat specialist living in highly fragmented salt marsh habitat in the San Francisco Estuary (California, USA). Methods: We surveyed for salt marsh harvest mice at 47 marsh patches throughout their range using a non-invasive genetic survey technique. We used occupancy modeling to estimate the effects of patch size, patch connectivity, matrix urbanization, and several habitat characteristics on occupancy probabilities. We evaluated occupancy at both coarse (e.g., among patches) and fine (e.g., within patches) spatial scales. Results: Patch size, connectivity, and matrix urbanization had significant effects on patch-occupancy. Within patches, occupancy was positively related to the presence of high-tide escape vegetation. Our data also revealed the extirpation of several geographically distinct populations, consistent with expectations due to reduced patch sizes and connectivity over the past century. Conclusions: Patterns of salt marsh harvest mouse patch-occupancy were consistent with the area-isolation paradigm. In addition, our models provide important guidelines of patch size and connectivity that can inform habitat conservation and restoration for this endangered species. Specifically, our data suggests that selecting restoration sites that are well-connected may be more beneficial than selecting larger, isolated sites. [ABSTRACT FROM AUTHOR]

Barrier coastlines and their associated ecosystems are rapidly changing. Barrier islands/spits, marshes, bays, and coastal forests are all thought to be intricately coupled, yet an understanding of how morphologic change in one part of the system affects the system altogether remains limited. Here we explore how sediment exchange controls the migration of different ecosystem boundaries and ecosystem extent over time using a new coupled model framework that connects components of the entire barrier landscape, from the ocean shoreface to mainland forest. In our experiments, landward barrier migration is the primary cause of back‐barrier marsh loss, while periods of barrier stability can allow for recovery of back‐barrier marsh extent. Although sea‐level rise exerts a dominant control on the extent of most ecosystems, we unexpectedly find that, for undeveloped barriers, bay extent is largely insensitive to sea‐level rise because increased landward barrier migration (bay narrowing) offsets increased marsh edge erosion (bay widening). Plain Language Summary: Barrier coastlines consist of barrier islands or spits, salt marshes, bays, and mainland forest. To understand how the migration and change in size of one ecosystem influences the others, we develop a new computer model that simulates the exchange of sediment between all ecosystems. Using this model, we find that salt marshes adjacent to barriers are rapidly lost when the barrier migrates and its sediment is washed onto the marsh, but can potentially expand and recover when the barrier is not migrating. Additionally, we find that changing the rate of sea‐level rise in the model does not significantly change the size of the bay because the effects of sea‐level rise on barrier migration and marsh edge erosion offset each other. Our simulations suggest that these interactions among different ecosystems result in complex evolution of coastal barrier systems and can be a leading cause of change. Key Points: Cross‐landscape interactions are explored in new model framework connecting entire barrier system from shoreface to mainland forestSimulations suggest barrier migration leads to rapid back‐barrier marsh loss, while barrier stability enables back‐barrier marsh recoveryBay extent is insensitive to sea‐level rise rates because of offsetting responses from barrier migration and marsh‐edge erosion processes [ABSTRACT FROM AUTHOR]

Living shorelines (LS) are a nature‐based restoration technique that aims to stabilize shorelines while enhancing multiple ecosystem services. In particular, LS are frequently promoted as beneficial for enhancing essential coastal habitats for fish and mobile crustaceans (nekton). In this study, we aimed to assess the effects of LS on nekton habitat across eight LS restoration sites in coastal Alabama, U.S.A., by applying widely‐used community metrics. Nekton abundance, species richness, evenness, and diversity tended to be higher in LS and adjacent unrestored control sites than along nearby hardened shorelines. Community metrics showed no clear effect of LS compared to their adjacent controls, with substantial among‐site variation masking any restoration effect. While this may suggest an ecological equivalence between restored and control sites, there are other possible interpretations; that a lack of difference reflects sampling the same populations at nearby control and restored sites, that differences do exist but sampling effort was insufficient to detect them, or that community metrics may be too insensitive for comparing the effects of various restoration approaches on nekton habitat quality. Further exploration of individual‐based metrics such as growth and condition of key species is warranted, as these may be more sensitive for assessing restoration outcomes and guiding future project designs. [ABSTRACT FROM AUTHOR]

Copyright of Natura Croatica is the property of Natura Croatica 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.)

Coastal wetlands worldwide are experiencing high rates of loss and degradation that may lead to a reduction in diversity in faunal populations. Since salt marsh habitats are subject to a multitude of stressors, evaluations of the genetic diversity, connectivity, and potential resilience of faunal communities within salt marsh habitats are relevant. This study characterizes mitochondrial DNA (mtDNA) diversity for three common faunal residents of salt marshes along the northern Gulf of Mexico. Gulf Killifish (Fundulus grandis) samples were characterized for 1077 bp of the concatenated nucleotide sequence corresponding to the Control Region and Nitrogen Dehydrogenase, Subunits 2 and 5. Daggerblade grass shrimp (Palaemon pugio) samples were characterized using 466 bp of 16sRNA sequence, and phloem-feeding planthoppers (Prokelisia marginata) were characterized using 372 bp of Cytochrome c Oxidase Subunit I (COI) sequence. For F. grandis, our data revealed high levels of haplotypic diversity, evidence of isolation by distance (IBD), and regional population structuring associated with the distribution of two distinct phylogroups and distinct historical demography signatures. P. pugio and P. marginata displayed low levels of haplotypic diversity and evidence of population structure, but both appear to contain only snapshots of the total potential diversity for these species in the Gulf of Mexico. Greater resolution of the patterns of historical demography of Gulf Killifish may be obtained in future studies by including localities from Florida and Mexico. For both P. pugio and planthoppers, future studies would benefit from the characterization of genetic markers with a higher degree of polymorphism. We conclude that despite these three species inhabiting the same habitats along the same stretch of coast, each is subject to a different combination of evolutionary forces, and this study was able to reconstruct differences in how the genetic variation in each of these species emerged, and how it is maintained. [ABSTRACT FROM AUTHOR]

Wetlands are natural sources of methane (CH4) emissions, providing the largest contribution to the atmospheric CH4 pool. Changes in the ecohydrological environment of coastal salt marshes, especially the surface inundation level, cause instability in the CH4 emission levels of coastal ecosystems. Although soil methane-associated microorganisms play key roles in both CH4 generation and metabolism, how other microorganisms regulate methane emission and their responses to inundation has not been investigated. Here, we studied the responses of prokaryotic, fungal and cercozoan communities following 5 years of inundation treatments in a wetland experimental site, and molecular ecological networks analysis (MENs) was constructed to characterize the interdomain relationship. The result showed that the degree of inundation significantly altered the CH4 emissions, and the abundance of the pmoA gene for methanotrophs shifted more significantly than the mcrA gene for methanogens, and they both showed significant positive correlations to methane flux. Additionally, we found inundation significantly altered the diversity of the prokaryotic and fungal communities, as well as the composition of key species in interactions within prokaryotic, fungal, and cercozoan communities. Mantel tests indicated that the structure of the three communities showed significant correlations to methane emissions (p < 0.05), suggesting that all three microbial communities directly or indirectly contributed to the methane emissions of this ecosystem. Correspondingly, the interdomain networks among microbial communities revealed that methane-associated prokaryotic and cercozoan OTUs were all keystone taxa. Methane-associated OTUs were more likely to interact in pairs and correlated negatively with the fungal and cercozoan communities. In addition, the modules significantly positively correlated with methane flux were affected by environmental stress (i.e., pH) and soil nutrients (i.e., total nitrogen, total phosphorus and organic matter), suggesting that these factors tend to positively regulate methane flux by regulating microbial relationships under inundation. Our findings demonstrated that the inundation altered microbial communities in coastal wetlands, and the fungal and cercozoan communities played vital roles in regulating methane emission through microbial interactions with the methane-associated community. [ABSTRACT FROM AUTHOR]

Nature-protected coastal plain areas in the Po River Delta, Italy, are subjected to periodic flooding. Such phenomena create temporary water habitats conducive to the development of salt marsh mosquitoes, such as Aedes caspius (Pallas) and Aedes detritus (Haliday), which cause significant nuisance impacting the tourist industry. Mosquito control is therefore required, but conflict arises about the need to safeguard endangered bird species typically nesting in the wetlands. Despite the fact that adopted mosquito control methods are designed to cause as little disturbance as possible, authorities responsible for nature conservation require that the possible impact of larval control activities are further reduced. These concerns have served as an incentive to seek out alternative control strategies, such as the enhancement of the predatory action of fish species inhabiting the salt marsh biotopes. The most abundant of these species is the native Aphanius fasciatus (Valenciennes) (Cyprinodontiformes Cyprinodontidae). The access of fish to isolated pools and lowlands subjected to occasional flooding can be promoted by connecting them to major permanent water bodies via shallow ditches or runnels, which are dug by hand. The results of four years of observations and larval sampling in a salt marsh area of about 4 ha, located in the natural reserve of "Sacca del Bellocchio" where a system of runnels has been planned and constructed, suggest that runnelling can be an effective, long-lasting larval control method, favouring the predatory action of fish. [ABSTRACT FROM AUTHOR]

Habitat fragmentation and loss reduce population size and connectivity, which imperils populations. Functional connectivity is key for species persistence in human-modified landscapes. To inform species conservation management, we investigated spatial genetic structure, gene flow and inferred dispersal between twelve breeding sites of the Natterjack toad (Bufo calamita); regionally Red-Listed as Endangered in Ireland. Spatial genetic structure was determined using both Bayesian and non-Bayesian clustering analysis of 13 polymorphic microsatellite loci genotyping 247 individuals. We tested the influence of geographic distance, climate, habitat, geographical features, and anthropogenic pressure on pairwise genetic distances between breeding sites using Isolation-by-distance and Isolation-by-resistance based on least-cost path and circuit theory models of functional connectivity. There was clear spatial structuring with genetic distances increasing with geographic distance. Gene flow was best explained by Isolation-by-resistance models with coniferous forestry plantations, bog, marsh, moor and heath, scrub, anthropogenic presence (Human Influence Index) and rivers (riparian density) identified as habitats with high resistance to gene flow while metapopulation connectivity was enhanced by coastal habitats (beaches, sand dunes and salt marshes) and coastal grassland. Despite substantial declines in census numbers over the past 15 years and its regional status as Endangered, the Natterjack toad population in Ireland retains high genetic diversity. If declines continue, maintaining habitat connectivity to prevent genetic erosion by management of coastal grasslands, pond construction and assisted migration through translocation will be increasingly important. [ABSTRACT FROM AUTHOR]

Positive species interactions, including facilitation and mutualism, are important in shaping ecological communities through the amelioration of stressful conditions. Facilitation results from traits (e.g., plant growth form) that create benefits for one or more interacting partners. The outcomes of facilitation depend on positive or negative feedbacks between partners, which can determine the stability of interactions over time. We can expand our understanding of these dynamics through a bidirectional approach that identifies the specific mechanisms creating benefits for the associated species, the traits related to those benefits, and the potential for feedbacks to affect amelioration by modifying traits. We characterized an association between the salt marsh plant Limonium carolinianum and mussel Geukensia sp. in the northern Gulf of Mexico. We used a field survey and three field experiments to establish the bidirectional effects of the association, the underlying mechanisms, and the relevant traits for each partner species. Mussels benefitted from Limonium canopies, which ameliorated high temperatures and predation for mussels, increasing survival and recruitment. These positive effects were particularly evident under larger canopies. Mussels enriched sediment organic matter and thus over time are expected to alleviate nutrient limitation for Limonium. Changes in functional traits of both species contributed to facilitation. Limonium both benefitted from and promoted higher mussel density, and mussels both allowed Limonium to grow or retain more leaves and benefitted from stress amelioration under larger canopies. The benefits of the association appear asymmetrical: mussels consistently benefitted in both experiments, but we found only modest positive effects on Limonium, and only over the longer term. These differences likely reflect variation in the seasonality and/or timescale of the facilitative mechanisms. The bidirectional and mechanistic design of our study revealed positive feedbacks that reinforced the traits conferring benefits to each partner, potentially stabilizing this positive interaction. Understanding how feedbacks influence the outcomes of facilitation is increasingly important as anthropogenic stressors increase globally. [ABSTRACT FROM AUTHOR]

Solar salterns and salt marshes are unique ecosystems with special physicochemical features and characteristic biota. Currently, there are very few studies focused on the impacts of pollution on these economic and ecological systems. Unfortunately, diversified pollution (metals, Polycyclic Aromatic Hydrocarbons, etc.) has been detected in these complex ecosystems. These hypersaline environments are under increasing threat due to anthropogenic pressures. Despite this, they represent a valuable source of microbial diversity, with taxa displaying special features in terms of environmental remediation capacities as well as economical species such as Artemia spp. (Branchiopoda) and Dunaliella salina (Chlorophyta). In this review, we discuss the impacts of pollution on these semi-artificial systems. Therefore, we have indicated the sentinel species identified in plankton communities, which can be used in ecotoxicological investigations in solar salterns. In future, researchers should increase their interest in pollution assessment in solar salterns and salt marshes. [ABSTRACT FROM AUTHOR]

Background: Anthropogenic pressures and climate change threaten the capacity of ecosystems to deliver a variety of services, including protecting coastal communities from hazards like flooding and erosion. Human interventions aim to buffer against or overcome these threats by providing physical protection for existing coastal infrastructure and communities, along with added ecological, social, or economic co-benefits. These interventions are a type of nature-based solution (NBS), broadly defined as actions working with nature to address societal challenges while also providing benefits for human well-being, biodiversity, and resilience. Despite the increasing popularity of NBS for coastal protection, sometimes in lieu of traditional hardened shorelines (e.g., oyster reefs instead of bulkheads), gaps remain in our understanding of whether common NBS interventions for coastal protection perform as intended. To help fill these knowledge gaps, we aim to identify, collate, and map the evidence base surrounding the performance of active NBS interventions related to coastal protection across a suite of ecological, physical, social, and economic outcomes in salt marsh, seagrass, kelp, mangrove, shellfish reef, and coral reef systems. The resulting evidence base will highlight the current knowledge on NBS performance and inform future uses of NBS meant for coastal protection. Methods: Searches for primary literature on performance of NBS for coastal protection in shallow, biogenic ecosystems will be conducted using a predefined list of indexing platforms, bibliographic databases, open discovery citation indexes, and organizational databases and websites, as well as an online search engine and novel literature discovery tool. All searches will be conducted in English and will be restricted to literature published from 1980 to present. Resulting literature will be screened against set inclusion criteria (i.e., population, intervention, outcome, study type) at the level of title and abstract followed by full text. Screening will be facilitated by a web-based active learning tool that incorporates user feedback via machine learning to prioritize articles for review. Metadata will be extracted from articles that meet inclusion criteria and summarized in a narrative report detailing the distribution and abundance of evidence surrounding NBS performance, including evidence clusters, evidence gaps, and the precision and sensitivity of the search strategy. [ABSTRACT FROM AUTHOR]

Salt marshes play an important role in the global nutrient cycle. The sediments in these systems harbor diverse and complex bacterial communities possessing metabolic capacities that provide ecosystem services such as nutrient cycling and removal. On the East Coast of the USA, salt marshes have been experiencing degradation due to anthropogenic stressors. Salt marsh islands within Jamaica Bay, New York City (USA), are surrounded by a large highly urbanized watershed and have declined in area. Restoration efforts have been enacted to reduce further loss, but little is known about how microbial communities develop following restoration activities, or how processes such as nitrogen cycling are impacted. Sediment samples were collected at two sampling depths from five salt marsh islands to characterize the bacterial communities found in marsh sediment including a post-restoration chronosequence of 3–12 years. We used 16s rRNA amplicon sequencing to define alpha and beta diversity, taxonomic composition, and predicted metabolic profile of each sediment sample. We found significant differences in alpha diversity between sampling depths, and significant differences in beta diversity, taxonomic composition, and predicted metabolic capacity among the five sampling locations. The youngest restored site and the degraded natural sampling site exhibited the most distinct communities among the five sites. Our findings suggest that while the salt marsh islands are located in close proximity to each other, they harbor distinct bacterial communities that can be correlated with post-restoration age, marsh health, and other environmental factors such as availability of organic carbon. Importance: Salt marshes play a critical role in the global nutrient cycle due to sediment bacteria and their metabolic capacities. Many East Coast salt marshes have experienced significant degradation over recent decades, thought largely to be due to anthropogenic stressors such as nitrogen loading, urban development, and sea-level rise. Salt marsh islands in Jamaica Bay (Queens/Brooklyn NY) are exposed to high water column nitrogen due to wastewater effluent. Several receding marsh islands have been subjected to restoration efforts to mitigate this loss. Little is known about the effect marsh restoration has on bacterial communities, their metabolic capacity, or how they develop post-restoration. Here, we describe the bacterial communities found in marsh islands including a post-restoration chronosequence of 3–12 years and one degraded marsh island that remains unrestored. We found distinct communities at marsh sites, despite their geographic proximity. Differences in diversity and community composition were consistent with changes in organic carbon availability that occur during marsh development, and may result in differences in ecosystem function among sites. [ABSTRACT FROM AUTHOR]

In this study, we examined the succession of soil microbial communities across a chronosequence of newly constructed salt marshes constructed primarily of fine-grained dredge material, using 16S rRNA amplicon sequences. Alpha diversity in the subsurface horizons was initially low and increased to reference levels within 3 years of marsh construction, while alpha diversity in the newly accumulating organic matter-rich surface soils was initially high and remained unchanged. Microbial community succession was fastest in the surface horizon (~ 24 years to reference equivalency) and became progressively slower with depth in the subsurface horizons (~ 30–67 years). Random forest linear regression analysis was used to identify important taxa driving the trajectories toward reference conditions. In the parent material, putative sulfate-reducers (Desulfobacterota), methanogens (Crenarchaeota, especially Methanosaeta), and fermenters (Chloroflexi and Clostridia) increased over time, suggesting an enrichment of these metabolisms over time, similar to natural marshes. Concurrently in the surface soils, the relative abundances of putative methane-, methyl-, and sulfide oxidizers, especially among Gammaproteobacteria, increased over time, suggesting the co-development of sulfide and methane removal metabolisms in marsh soils. Finally, we observed that the surface soil communities at one of the marshes did not follow the trajectory of the others, exhibiting a greater relative abundance of anaerobic taxa. Uniquely in this dataset, this marsh was developing signs of excessive inundation stress in terms of vegetation coverage and soil geochemistry. Therefore, we suggest that soil microbial community structure may be effective bioindicators of salt marsh inundation and are worthy of further targeted investigation. [ABSTRACT FROM AUTHOR]

Salt marshes are among the most valuable ecosystems on earth; however, previous research has reported global losses in their extent accompanied by an impairment of their ecological processes. Nonetheless, investigations on salt marsh vegetation ecology are still lacking in many sites, including in Ria de Aveiro. As such, this study aimed to (1) monitor, characterize, and understand the evolution of salt marsh vegetation communities at three different study sites with different environmental conditions and stages of degradation, where we also sought to (2) identify the main delimiting abiotic factors associated with the distribution of the main species. To do so, a multidisciplinary approach that involved the survey of vegetation from permanent transects and the collection of ecological, physicochemical, and hydrodynamic data at sampling points within the monospecific stands of the main species was reported. The results showed that, of the abiotic factors deemed as the main delimiting forces of salt marsh vegetation, the soil elevation and hydroperiod were the most restrictive factors, as they ultimately influenced species composition at the different study sites and explained most of the variation observed between the studied monospecific stands. [ABSTRACT FROM AUTHOR]

Deserts are stressful environments where the living beings must acquire different strategies to survive due to the water stress conditions. From the late Albian to the early Cenomanian, the northern and eastern parts of Iberia were the location of the desert system represented by deposits assigned to the Utrillas Group, which bear abundant amber with numerous bioinclusions, including diverse arthropods and vertebrate remains. In the Maestrazgo Basin (E Spain), the late Albian to early Cenomanian sedimentary succession represents the most distal part of the desert system (fore-erg) that was characterised by an alternation of aeolian and shallow marine sedimentary environments in the proximity of the Western Tethys palaeo-coast, with rare to frequent dinoflagellate cysts. The terrestrial ecosystems from this area were biodiverse, and comprised plant communities whose fossils are associated with sedimentological indicators of aridity. The palynoflora dominated by wind-transported conifer pollen is interpreted to reflect various types of xerophytic woodlands from the hinterlands and the coastal settings. Therefore, fern and angiosperm communities abundantly grew in wet interdunes and coastal wetlands (temporary to semi-permanent freshwater/salt marshes and water bodies). In addition, the occurrence of low-diversity megafloral assemblages reflects the existence of coastal salt-influenced settings. The palaeobotanical study carried out in this paper which is an integrative work on palynology and palaeobotany, does not only allow the reconstruction of the vegetation that developed in the mid-Cretaceous fore-erg from the eastern Iberia, in addition, provides new biostratigraphic and palaeogeographic data considering the context of angiosperm radiation as well as the biota inferred in the amber-bearing outcrops of San Just, Arroyo de la Pascueta and La Hoya (within Cortes de Arenoso succesion). Importantly, the studied assemblages include Afropollis, Dichastopollenites, Cretacaeiporites together with pollen produced by Ephedraceae (known for its tolerance to arid conditions). The presence of these pollen grains, typical for northern Gondwana, associates the Iberian ecosystems with those characterising the mentioned region. [ABSTRACT FROM AUTHOR]

Salt marshes are considered among the ecosystems with the highest capacity for carbon sequestration. However, studies have mainly focused on tidal salt marshes, while knowledge about non-tidal salt marshes, which prevail in the Mediterranean Basin, is currently scarce. Consequently, we aimed to (1) estimate the carbon stocks of the vegetation, litter, and soil of three natural Habitats of Community Interest of a Mediterranean non-tidal salt marsh–a halophilous scrub, a salt meadow, and a glasswort sward–and (2) determine how differences in floristic composition and community structure among habitats over 1 year are related to the amount and distribution of carbon stored in plants and soils. Results show that the halophilous scrub and the salt meadow were constituted by mature plant communities with overall stable carbon stocks in the vegetation, litter, and soil (0–20 cm), which were approximately 4 and 2.5 times larger, respectively, than those found in the glasswort sward (1013 ± 40 g C m−2). However, while the salt meadow and the glasswort sward had more carbon stored in the soil than in the vegetation (approximately 3 and 7.5 times more, respectively), the halophilous scrub had similar amounts in both compartments (2248 ± 388 and 1566 ± 179 g C m−2 in the soil and vegetation, respectively). Sarcocornia fruticosa represented 93.5% of the total plant biomass of the halophilous scrub, which highlights the importance of this species in maintaining carbon stocks in this Mediterranean non-tidal salt marsh. [ABSTRACT FROM AUTHOR]

Community structure and dynamics are influenced by numerous abiotic and biotic factors requiring large datasets to disentangle, which are often difficult to obtain over the spatiotemporal scales necessary for meaningful analysis. The approach outlined here illustrates one potential solution to this problem by leveraging computer vision methods to gain accurate, in-depth community data from ~ 10,000 photographs of salt marsh plants across an elevation gradient at Sapelo Island, GA, USA. A convolutional neural network (ResNext101) trained to detect the 6 dominant plant species achieved high accuracy for all species, allowing mapping of high-marsh plant communities over gradients in elevation and pore-water salinity. To statistically analyze the high-resolution mapping data, we constructed a structural equations model using the generated data as informed by prevailing ecological theory for salt marshes in the Southeastern United States. Model fit to data was strong, with R2 values for five of six plant species > 0.7. The distribution of the rare understory perennial Limonium carolinianum, however, was not accurately predicted by the model. Modeled effects of abiotic factors elevation and soil salinity were commensurate with the literature. Biotic interactions also largely conformed to ecological understanding of Southeastern marshes, but a potentially novel positive interaction between Borrichia frutescens and Batis maritima was observed. Overall, this approach shows promise as a method of efficiently generating and statistically analyzing community data for sessile species at scales not previously possible. This study contributes to a growing body of work developing integrated computer vision and big data techniques for ecological field work. [ABSTRACT FROM AUTHOR]

Coastal wetlands are rapidly disappearing worldwide due to a variety of processes, including climate change and flood control. The rate of loss in the Mississippi River Delta is among the highest in the world and billions of dollars have been allocated to build and restore coastal wetlands. A key question guiding assessment is whether created coastal salt marshes have similar biodiversity to preexisting, reference marshes. However, the numerous biodiversity metrics used to make these determinations are typically scale dependent and often conflicting. Here, we applied ecological theory to compare the diversity of different assemblages (surface and below‐surface soil microbes, plants, macroinfauna, spiders, and on‐marsh and off‐marsh nekton) between two created marshes (4–6 years old) and four reference marshes. We also quantified the scale‐dependent effects of species abundance distribution, aggregation, and density on richness differences and explored differences in species composition. Total, between‐sample, and within‐sample diversity (γ, β, and α, respectively) were not consistently lower at created marshes. Richness decomposition varied greatly among assemblages and marshes (e.g., soil microbes showed high equitability and α diversity, but plant diversity was restricted to a few dominant species with high aggregation). However, species abundance distribution, aggregation, and density patterns were not directly associated with differences between created and reference marshes. One exception was considerably lower density for macroinfauna at one of the created marshes, which was drier because of being at a higher elevation and having coarser substrate compared with the other marshes. The community compositions of created marshes were more dissimilar than reference marshes for microbe and macroinfauna assemblages. However, differences were small, particularly for microbes. Together, our results suggest generally similar taxonomic diversity and composition between created and reference marshes. This provides support for the creation of marsh habitat as tools for the maintenance and restoration of coastal biodiversity. However, caution is needed when creating marshes because specific building and restoration plans may lead to different colonization patterns. [ABSTRACT FROM AUTHOR]

Diamondback terrapins (Malaclemys terrapin) inhabit estuarine environments, and adult females typically nest in coastal uplands. Hatchlings emerging from nests overwinter on land and in coastal salt marshes, but the proportions that use each land cover type is not well documented. From 2019 to 2021, we tracked movements and habitat use of hatchlings post‐emergence to determine the importance of upland overwintering sites to a terrapin population in Rhode Island, USA. In late summer and early fall, we attached a radio‐transmitter and passive integrated transponder (PIT) tag (n = 46) or only a PIT tag (n = 132) to carapaces of hatchlings emerging from nests. From August to June, we tracked the hatchlings via radio‐telemetry and a sweeping PIT tag antenna, successfully documenting the fates of 46.6% of them (n = 83). This group included 23 hatchlings that overwintered in the upland, 11 hatchlings that moved to the salt marsh in fall, 46 predated hatchlings, and 3 hatchlings dead from unknown causes. Upon emergence from their nests, 68% of hatchlings dispersed toward water and 32% of hatchlings dispersed away from water. In the uplands, hatchlings typically overwintered within about 2 m of habitat edges. Movement in the uplands peaked from late August to early October, then ceased until hatchlings re‐emerged in late April through early June. To protect terrapins, we recommend limiting the use of heavy equipment (e.g., mowers, tillers) in vegetated uplands near nest sites, and scheduling vegetation management for colder months (Nov–Mar in New England, USA) when hatchlings are inactive. [ABSTRACT FROM AUTHOR]

Salt marsh vegetation, mudflat and salt production are common features in worldwide coastal areas; however, their influence on microbial community composition and structure has been poorly studied and rarely compared. In the present study, microbial community composition (phospholipid fatty acid (PLFA) profiling and 16S rRNA gene sequencing (bacterial and archaeal)) and structure, enzymatic activities and abundance of functional genes in the sediments of salt ponds (crystallizer, condenser and reservoir), mudflat and vegetated mudflat were determined. Enzyme activities (β-glucosidase, urease and alkaline phosphatase) were considerably decreased in saltpan sediments because of elevated salinity while sediment of vegetated mudflat sediments showed the highest enzyme activities. Concentrations of total microbial biomarker PLFAs (total bacterial, Gram-positive, Gram-negative, fungal and actinomycetes) were the highest in vegetated mudflat sediments and the lowest in crystallizer sediments. Nonmetric-multidimensional scaling (NMDS) analysis of PLFA data revealed that the microbial community of crystallizer, mudflat and vegetated mudflat was significantly different from each other as well as different from condenser and reservoir. The most predominant phyla within the classified bacterial fractions were Proteobacteria followed by Firmicutes, Bacteroidetes and Planctomycetes, while Euryarchaeota and Crenarchaeota phyla dominated the classified archaeal fraction. Cyanobacterial genotypes were the most dominant in the condenser. Mudflat and vegetated mudflat supported a greater abundance of Bacteroidetes and Actinobacteria, respectively. The results of the present study suggest that salt ponds had significantly decreased the microbial and enzyme activities in comparison to mudflat and vegetated mudflat sediments due to very high salinity, ionic concentrations and devoid of vegetation. The present study expands our understanding of microbial resource utilization and adaptations of microorganisms in a hypersaline environment. [ABSTRACT FROM AUTHOR]

Wetland ecology monitoring is an essential technical guarantee for the protection and restoration of the fragile ecosystem of wetlands. Due to the degradation of keystone species Suaeda HeteropteraPall. (S. Heteroptera) in the Liao River Estuary wetland, the Wetland Image Monitoring System (WIMS) was established to obtain real-time, continuous, high spatiotemporal resolution data about the coverage and height of S. Heteroptera. Based on the monitoring data, we elicited the best model to describe the variation of the coverage and height for S. Heteroptera. The results showed that the growth of S. Heteroptera could be divided into three stages: rapid growth stage (April–May), slow growth stage (June–August), and stable stage (after September). The Bertalanffy model was the best choice for the coverage simulation of S. Heteroptera. The segment model composed of the linear and Gompertz models was suitable for the height simulation of S. Heteroptera, which could effectively reduce the relative error compared with the single model. In addition, the WIMS could potentially capture other important ecological factors in local regions, including benthic animals, birds, waterlogging conditions, etc. Although WIMS has some application limitations, the high spatiotemporal resolution and relatively low cost make it an effective tool to explore the degradation of typical ecosystems under climate change and human activities. [ABSTRACT FROM AUTHOR]

Noninvasive genetic surveys, often conducted by collecting fecal samples, have become a popular tool for surveying wildlife, but have primarily been applied to species with large and conspicuous scat. Although many small mammals are threatened, endangered, or data deficient, noninvasive genetic surveys have rarely been applied due to the challenges of detecting their inconspicuous fecal pellets. As part of a broader study of the endangered salt marsh harvest mouse (Reithrodontomys raviventris), we developed a noninvasive genetic survey technique for the community of small mammals in their putative range. We designed bait stations to passively collect fecal samples from rodents, and developed a multiplex primer set that amplified unique fragment sizes for salt marsh harvest mice and four other sympatric species. We tested the primer set on positive controls and on fecal pellets collected from bait stations at two regularly monitored field sites known to have very different densities of salt marsh harvest mice. The multiplex amplified DNA from all five species, even when all five species were present in a single sample. A positive species identification was made for all field-collected samples, and 43% of these field-collected samples had multispecies detections. The combination of bait stations and genetic species identification proved to be an effective means of noninvasively surveying small mammals in potential salt marsh harvest mouse habitat. The sampling technique should be applicable to a wide variety of small mammals in other systems. [ABSTRACT FROM AUTHOR]

Metabolic rate is a basic individual metric that extends beyond the individual to link the ecology of populations, communities, and ecosystems via its role as a central component of energy budgets. Metabolic rates are often measured indirectly by quantifying respiration under simplified, standard laboratory conditions. This approach limits the application of these measurements to a small range of conditions that commonly do not reflect natural field conditions. We measured metabolic rates of the squareback marsh crab Armases cinereum under field conditions. Previous work highlights that movement of individual A. cinereum, especially females, provides a potential spatial subsidy of energy, as individuals consume foods in salt marshes and then transfer the resulting energy to upland forest ecosystems. We show that metabolic rate increases with size for both males and females and that metabolic rates are influenced by temperature and by whether females are vitellogenic. The metabolic rates that we measured more closely approximate field metabolic rates than standard metabolic rates and demonstrate that individual crabs experience high energy expenditures, reducing the amount of energy that may be transferred as a subsidy between marsh and forest as a result of the daily movements of individual crabs. Our measurements are therefore also a key component for the construction of an energy budget for this species. [ABSTRACT FROM AUTHOR]

The successful implementation and sustainability of many marsh restoration efforts, including coastal adaptation to buffer inundation and mitigate sea level rise, often hinges upon support from surrounding human communities. Yet, stakeholder engagement in these projects remains relatively undervalued and underutilized. We present the Social-Ecological Systems, Adaptive Management, and Engagement (SESAME) framework that provides reciprocal connections between the human and ecological components of restoration efforts and the resulting management and engagement needs. We built and describe this framework through discussion of two case studies of coastal restoration efforts in southern New England salt marshes. The first case study focuses on the use of sediment placement to increase the elevation of the surface of a drowning marsh in Rhode Island as an interim measure to protect against sea level rise. The second case study describes the use of living shorelines for erosion mitigation on a salt marsh in Massachusetts. These cases included significant partner and stakeholder engagement and provided important lessons learned for practical implementation of the SESAME framework. Valuable lessons included the need for engagement throughout the entirety of the process, specific clarification of roles within the restoration efforts, and flexibility in implementation and goal setting. [ABSTRACT FROM AUTHOR]

As coastal ecosystems become widely recognized for their capacity to sequester carbon (blue carbon), standard accounting methodologies for the generation of carbon credits are being developed. To ensure the applicability of these standards across blue carbon ecosystems, we investigated organic carbon provenance and burial in salt marshes and seagrass meadows of an arid, upwelling‐dominated Eastern Pacific lagoon. We found low carbon density in benthic sediments of Bahía de San Quintín (5.9 ± 0.5 mg C cm−3), only marginally higher in Zostera marina beds (6.9 ± 0.5 mg C cm−3), likely due to remineralization and hydrodynamically driven export of seagrass material, resulting in low carbon burial rates (4.5 ± 2.5 g C m−2 yr−1). Sediment organic carbon is mainly controlled by the fraction of fine sediment and its source is largely allochthonous, although sources differ spatially. Salt marshes at San Quintín derive 40% of their organic matter from autochthonous material and exhibit higher carbon burial rates (up to 414.7 ± 28.6 g C m−2 yr−1) and sediment carbon densities (32.0 ± 0.7 mg C cm−3) compared to benthic sediments. This study emphasizes the connectivity of blue carbon habitats with marsh plant detritus supplementing benthic carbon burial and incorporation of detrital eelgrass in marsh sediments. Our findings highlight the importance of allochthonous organic matter for carbon sequestration in blue carbon habitats, suggesting standard accounting practices that deduct allochthonous organic matter would miss the full potential for carbon burial. [ABSTRACT FROM AUTHOR]

Salt marsh habitats contain some of the highest quantities of soil organic carbon (C) per unit area, but increasing anthropogenic stressors threaten their ability to maintain themselves as large C reservoirs in some regions. We quantify rates of C gas exchange (methane [CH4] and carbon dioxide [CO2]) monthly across a 16‐month period from a low nitrogen "reference" salt marsh on Cape Cod in New England using static chambers. While the summer period is the most dynamic period of marsh C gas exchange, we observed substantial fluxes in the early summer through late fall, highlighting the importance of including shoulder seasons in studies of marsh C exchange. We estimate annual ecosystem respiration between 108 and 252 g C m−2 yr−1, which varied based on temperature and elevation. This flux is lower than in other nearby marshes, which we attribute to the frequently inundated, microtidal nature of the site, resulting in the majority of respired CO2 being exported via lateral, not vertical, fluxes from this marsh. We observed significantly higher temperature sensitivity from the low elevation of the marsh compared to the high marsh. Recent acceleration in the rate of sea level rise is leading to a well‐documented expansion of low marsh into high marsh vegetation zones in this marsh system and others in the region. While rates of C burial are higher in the low marsh compared to the high marsh, the higher temperature sensitivity of respiration in the low marsh may diminish the longevity of marsh C stocks with climate warming. Plain Language Summary: Salt marshes are hot spots of carbon sequestration, storing more carbon per unit area than many other ecosystems. We quantify rates of methane (CH4) emissions and carbon dioxide (CO2) exchange monthly across a 16‐month period from a relatively undisturbed salt marsh in New England and estimate annual rates of ecosystem respiration from the marsh. Ecosystem respiration appears lower at this site compared to other marshes, likely due to frequent inundation and microtidal nature, resulting in large lateral exports of respired carbon with ebbing tides. For the first time, we examine the response functions of ecosystem respiration in a fully saline marsh across the marsh elevation gradient. Per unit temperature increase, we see significantly more CO2 respired from the low marsh compared to the high marsh (i.e., higher temperature sensitivity). Due to accelerated rates of sea level rise, low marsh habitats are increasingly expanding into high marsh zones; our data indicate the large C stocks in low marsh habitats are more vulnerable to respiratory losses as a result of warming, compared to high marsh systems. This work improves our understanding of the temperature sensitivity of respiration in aquatic systems in general, which pales in comparison to knowledge from terrestrial systems. Key Points: Including shoulder seasons is critical in studies of marsh C exchangeEstimates of annual ecosystem respiration are low at this marsh, due to microtidal nature and elevated lateral fluxesThe temperature sensitivity of ecosystem respiration was significantly higher from the low marsh relative to the high marsh [ABSTRACT FROM AUTHOR]

Keywords: ambush predator; blue crabs; Callinectes sapidus; fiddler crabs; Sesarma reticulatum; sit-and-wait; Uca pugnax EN ambush predator blue crabs Callinectes sapidus fiddler crabs Sesarma reticulatum sit-and-wait Uca pugnax 1 4 4 10/06/22 20221001 NES 221001 It is low tide in a salt marsh. If purple marsh crabs do help blue crabs hunt in the marsh at low tide, then blue crabs should be more abundant in marshes where purple marsh-crab grazing is substantial versus marshes where it is limited. Most attacks happened when a fiddler crab was in front of the blue crab, but occasionally when a fiddler crab was behind or beside the blue crab. Uca pugnax, ambush predator, blue crabs, Callinectes sapidus, fiddler crabs, Sesarma reticulatum, sit-and-wait. [Extracted from the article]

In December 2022, representatives adopted the Kunming-Montreal Global Biodiversity Framework (GBF). The overarching goal of the agreement is to halt biodiversity loss and restore natural ecosystems – and a much-cited target is the "30x30" target of protecting and restoring 30% of Earth by 2030. Salt marshes are highly productive coastal ecosystems relevant for both biodiversity and climate change mitigation but have experienced historical major losses and are among the habitats in need of protection and restoration. Currently, there is little knowledge about how salt marshes are valued from a societal perspective, which has important management implications. This is particularly the case in the Nordic region where awareness of these habitats is low. Using survey data from Norway, Sweden, Finland, Denmark, and Germany, this study contributes understanding how citizens value salt marshes by examining support for different management initiatives framed as contributing to the goal of either biodiversity protection or climate change mitigation. Generally, both respondents primed with information about the importance of salt marshes for biodiversity and for climate change mitigation were supportive of the management initiatives despite having little previous knowledge of salt marshes. For one initiative, respondents who were informed of the importance of salt marshes for biodiversity were slightly more likely to support the management initiative than those informed about the importance of salt marshes for climate change mitigation. Our study provides guidance for assessment of trade-offs from a human valuation perspective, thus supporting policy makers when considering arguments for salt marsh management within the context of the 30x30 targets for protected areas. • When salt marshes were framed as important ecosystems, there was public support for management initiatives. • Respondents primed with information on the potential importance of salt marshes for climate change mitigation were not more supportive of management initiatives. • Initiatives with the least direct monetary contribution gained the most public support. • Public support for salt marsh management initiatives differed based on country and, in some cases, age and gender. [ABSTRACT FROM AUTHOR]

Microbiologically driven ecosystem processes can be profoundly altered by alien plant invasions. There is limited understanding of the ecological mechanisms orchestrating different microbial constituents and their roles in emerging functional properties under plant invasions. Here, we investigated soil microbial communities and functions using high‐throughput amplicon sequencing and GeoChip technology, respectively, along a chronological gradient of smooth cordgrass invasion in salt marshes located in the Yellow River Estuary, China. We found a positive correlation between microbial diversity and the duration age of invasion, and both bacterial and fungal communities showed consistent changes with invasion. Soil microbial metabolic potential, as indicated by the abundance of microbial functional genes involved in biogeochemical cycling, decreased in response to invasion. As a consequence, declining soil microbial metabolisms as a result of plant invasion facilitated carbon accumulation in invaded salt marshes. Bacteria and fungi exhibited distinct contributions to assembly processes along the invasion gradient: bacterial communities were mainly driven by selection and dispersal limitation, while fungi were dramatically shaped by stochastic processes. Soil microbial‐mediated functions were taxon‐specific, as indicated by community–function relationships. This study demonstrates the distinct contributions of microbial constituents to microbial community assembly and functions and sheds light on the implications of plant invasion on microbiologically driven ecosystem processes in coastal wetlands. [ABSTRACT FROM AUTHOR]

Estuary health indicators sit alongside metrics for air, groundwater, lakes and rivers, supporting a more integrated view of estuary health. Another milestone in estuary management is the development of an estuary health module on the Land Air Water Aotearoa (LAWA) website.[4] The inability to measure estuarine ecological health in a standardised manner has been a major impediment to estuarine management in Aotearoa. Estuaries are unique ecosystems where fresh and salt waters mix, connecting land to the ocean. [Extracted from the article]

Sea level rise is causing an increase in salt water encroachment and flooding in many coastal habitats, and increasing salinity can have negative impacts on plant communities. The objective of our research was to determine the impact of salinity on salt marsh plant community structure on Horse Island, South Carolina. We investigated variation in plant cover and height with distance from a tidal creek and the effect of increasing salinity on seedling emergence from the seed bank. We established three transects in the salt marsh habitat and recorded plant species presence, percent cover of each species, and height of the tallest individual of each species in 11 plots along each transect. Total plant cover was consistent from 0 to 24 m and increased from 24 to 40 m from the tidal creek; several species only occurred 36-40 m from the tidal creek. Percent cover of Spartina alterniflora, the dominant species, increased from 24 to 36 m from the tidal creek. The height of S. alterniflora was negatively correlated with percent cover of S. alterniflora and distance from the tidal creek. To assess the seed bank, we established 12 plots in the salt marsh-maritime forest ecotone, and soils collected from plots were assigned to each of four salinity treatments (0, 6, 12, and 26 ppt). Across all treatments, only one seedling emerged from the soil. The cover, height, and distribution of salt marsh species on Horse Island are likely to change as sea level continues to rise, but the role of the seed bank in affecting plant community structure remains unclear. [ABSTRACT FROM AUTHOR]