Salt Marsh Habitats Research Articles

A first look at sea-lavenders genomics – can genome wide SNP information tip the scales of controversy in the Limonium vulgare species complex?

BackgroundSea-lavenders (Limonium Mill., Plumbaginaceae) are a cosmopolitan group of diploid and polyploid plants often adapted to extreme saline environments, with a mostly Tethyan distribution, occurring in the Mediterranean, Irano-Turanian, Euro-Siberian and in the New World. The halophylic Limonium vulgare polyploid complex in particular, presents a large distribution throughout extreme salt-marsh habitats and shows little morphological but high taximetric variation, frequently blurring species delimitation. In this work we pursue three main goals: assert whether SNP data from polyploid individuals has the resolution to distinguish the seven sampled species, to better understand how genetically structured Limonium vulgare is, and attempt to identify specific molecular mechanisms for the differentiation between L. maritimum and L. vulgare. For this purpose, 95 individuals were genotyped using Genotyping by Sequencing (GBS), which were assembled as two independent datasets using ipyrad. All analyses performed downstream of assembly were fully automated. Phylogenetic inference, PCA, and admixture plots were used to infer answers to the study’s main goals.ResultsClose to 10,000 SNPs were obtained for each dataset. Phylogenetic analyses reveal that polyploid data can be used to infer species relationships. Population structure analyses suggest a genetically structured L. vulgare. A set of 34 SNPs were found to be fully segregated between L. vulgare and L. maritimum, two of which are potentially linked to proteins that might be involved in the speciation process.ConclusionDespite polyploid data analyses shortcomings, GBS generated SNPs have the resolution to discern all seven included species. Limonium vulgare revealed pronounced genetic structure along a geographical north-south cline. L. maritimum always appears as a distinct genetic entity. Segregated SNPs between L. vulgare and L. maritimum indicate salinity response and morphological trait control genes as potentially interesting to follow up for studying these species’ divergence process.

Relating absolute abundance of an estuarine fish to habitat area in an urbanizing environment

Organisms that rely on salt marsh habitat are an important trophic link, helping to maintain estuarine ecosystem productivity. We used GIS to quantify intertidal (assumed salt marsh) area from aerial photographs taken in 1939 and from software-supplied satellite imagery taken in 2021 for tidal creeks in North Carolina (USA) that have experienced minor (<20%), moderate (20-60%), or substantial (>60%) losses of intertidal habitat over the 8 decades. The current (2022) absolute abundance of adult Fundulus heteroclitus, a trophically important resident fish in US Atlantic estuaries, was estimated over each season in each creek by fitting a Lincoln-Petersen model to tag-recapture data. Current abundances of F. heteroclitus were lowest in creeks with the lowest intertidal area. The median and 2.5/97.5 credible intervals of the posterior probability distribution for the slope of a regression model relating current fish abundance to current intertidal area were positive, demonstrating that intertidal area was a meaningful covariate of abundance. Loss of intertidal area in the creeks between 1939 and 2021 ranged from 8 to 93%. The correlation between current intertidal area and historical loss of this habitat was negative and significant (Pearson r = -0.91, p = 0.012). Parameters from the regression relating current abundance to intertidal area were used to estimate historic F. heteroclitus abundances in each creek using GIS-derived estimates of historic intertidal area. Historic abundances were predicted to have been on average (across study creeks) 7.5 times greater in 1939 than in 2022. Reduced abundances, and thus reduced trophic relay by F. heteroclitus to higher-order consumers, can be expected in estuaries that have lost salt marsh due to inter-decadal development.

A novel coniothyrium-like genus in <i>Coniothyriaceae</i> ( <i>Pleosporales</i>) from salt marsh ecosystems in Thailand

In this study, a novel coniothyrium-like genus <italic>Coniothyrioides</italic> is introduced to <italic>Coniothyriaceae</italic> based on a fresh fungal collection from salt marsh habitats in Thailand. Coniothyrium-like taxa are taxonomically controversial and have been classified into different families in <italic>Pleosporales</italic> such as <italic>Didymosphaeriaceae</italic> (<italic>Alloconiothyrium</italic> and <italic>Paraconiothyrium</italic>), <italic>Coniothyriaceae</italic> (<italic>Coniothyrium</italic>) and <italic>Didymellaceae</italic> (<italic>Microsphaeropsis</italic>). However, our novel genus shares similar morphology to some key characters in <italic>Coniothyriaceae</italic> in having dark, globose pycnidia, uni-locular conidiomata, a central ostiole, a peridium of <italic>textura</italic> <italic>angularis</italic> cells, and doliiform conidiogenous cells with a periclinal thickening at the apex, while conidial morphologies are diverse. The presence of setae arising from the outer peridial wall is the main difference between <italic>Coniothyrioides</italic> and other closely related <italic>Coniothyriaceae</italic> genera. Phylogenetically, LSU-SSU-ITS sequence analyses confirm the placement of this novel genus as a distinct lineage within <italic>Coniothyriaceae</italic>. Species boundaries were defined, based on morphology and multi-gene phylogenetic analyses using maximum likelihood and Bayesian inference analyses. The comprehensive descriptions and micrographs are provided. Our findings expand the taxonomic knowledge of <italic>Ascomycota</italic> in salt marsh ecosystems.

Improved mapping of coastal salt marsh habitat change at Barnegat Bay (NJ, USA) using object-based image analysis of high-resolution aerial imagery

Tidal wetlands are valued for the ecosystem services they provide yet are vulnerable to loss due to anthropogenic disturbances such as land conversion, hydrologic modifications, and the impacts of climate change, especially accelerating rates of sea level rise. To effectively manage tidal wetlands in face of multiple stressors, accurate studies of wetland extent and trends based on high-resolution imagery are needed. We provide salt marsh delineations for Barnegat Bay, New Jersey, by means of object-based image analysis of high-resolution aerial imagery and digital elevation models. We performed trends analyses of salt marsh extent from 1995 to 2015 and estimated drivers of marsh area change. We found that in 1995, 8830 ± 390 ha were covered with marsh vegetation, while in 2015 only 8180 ± 380 ha of salt marsh habitat remained. The resulting net loss rate of 0.37% yr−1 is equivalent to historic loss rates since the 1970s, indicating that despite regionally accelerating relative sea level rise and purported eutrophication, salt marsh loss rates at Barnegat Bay remain steady. The main drivers of salt marsh loss are excavations for mosquito control (409 ha), edge erosion (303 ha) and ponding (240 ha). Upland migration of salt marsh did not completely mitigate these losses but accounted for a gain of 147 ha of tidal marsh habitat. The methodology presented herein yielded accurate salt marsh delineations (>90%) and trend detection (85%), outperforming low-resolution wetland delineations used in coastal management. This study demonstrates the suitability of high-resolution imagery for the detection of open water features. For the purposes of salt marsh change detection and the identification of change drivers, management and conservation agencies should make use of high-resolution imagery whenever feasible.

Suitability of compensatory saltmarsh habitat for feeding and diet of multiple estuarine fish species

AbstractSaltmarsh provides essential fish feeding and nursery habitat but has globally declined by 50%. We used a statistical block design to compare fish feeding activity within human‐engineered or “re‐aligned” saltmarsh to established saltmarsh. Linear and multivariate modelling highlighted that Thinlip Mullet (Chelon ramada) and European Bass (Dicentrarchus labrax) feeding rates were 16% and 31% lower within re‐aligned than established saltmarshes, whereas Gobies (Pomatoschistus spp.) fed at the same rate as in both habitats. Analysis of European bass and Goby gut contents highlighted that important detritivorous prey species were up to 85.6% lower in re‐aligned sites. Lower vegetation density may have negatively affected the feeding ecologies of fishes within re‐aligned sites. However, due to the ecological value and potential for further improvement or habitat development, continued assessment of the beneficial effects of re‐aligned sites for fisheries and net gain perspectives is needed.

Introduced Spartina anglica modifies fish habitat in southern temperate succulent saltmarshes

Vegetation changes in saltmarsh habitat can influence fish assemblages and abundance. In Tasmania, Australia, mid‐latitude succulent saltmarsh communities have been invaded by the introduced tall grass, Spartina anglica. Eradication efforts have been ongoing since the 1990s with purported benefits for fish access to intertidal foraging grounds, but a lack of knowledge of the impact of S. anglica on fish limits understanding of the benefits and effectiveness of native habitat restoration. Here, we investigate whether fish assemblages in native saltmarshes and non‐native S. anglica grassland differ in species diversity, fish abundance, and size class distribution. We used buoyant pop nets to sample fishes in Sarcocornia quinqueflora herbland and S. anglica grassland swards at three sampling stations in northwest Tasmania. Very few individuals and low species diversity were recorded in both vegetation types at the sampling station with the most well‐established S. anglica infestation. Elsewhere, richness and diversity were higher in S. quinqueflora herbland. Overall fish abundance was higher in S. quinqueflora than in S. anglica, with a very strong effect at one sampling station. Fewer small individuals of the numerically dominant Atherinosoma microstoma were recorded in S. anglica, potentially indicating impaired nursery function. Our results provide important insights for S. anglica control, as we are the first to demonstrate a relationship between S. anglica presence and fish characteristics in southern Australian saltmarsh. These results indicate that S. anglica control is valuable for fish conservation. An extension of our research to document the effects of S. anglica removal on fishes is desirable.

Innovative tidal control successfully promotes saltmarsh restoration

The reduction of saltmarsh habitat at a global scale has seen a concomitant loss of associated ecosystem services. As such, there is a need and a push for habitat rehabilitation. This study examined an innovative saltmarsh restoration project in Australia which sought to address the threats of mangrove encroachment and sea level rise. The project was implemented in 2017, using automated hydraulic control gates, termed “SmartGates,” to lower the tidal regime over one site, effectively reversing sea level rise at a local level. Measured indicators of saltmarsh cover, number of species, seedling counts, and saltmarsh assemblages all showed significant positive development over time, with trends varying based on saltmarsh zone. The saltmarsh, predominantly Sarcocornia quinqueflora, developed from remnant supralittoral (previously high) marsh which remained at 45% cover to achieve over 15% coverage across the cleared habitat after 3 years. Slower development in the low marsh (&lt;5%) compared to other zones contrasts with other saltmarsh restoration studies which may be due to the unique nature of the restoration method or the nature of Australian saltmarsh species which favor higher elevations and drier conditions. The development of saltmarsh at the treatment site was found to track toward that at comparison sites over time, becoming similar to some comparison sites by the studies end. This study highlights the usefulness of the novel restoration method used and of the measured indicators for assessing saltmarsh development. This innovative tidal control method could play an important role in the future of saltmarsh restoration worldwide.

Using citizen science to estimate surficial soil Blue Carbon stocks in Great British saltmarshes

A new saltmarsh soil dataset comprising of geochemical and physical property data from 752 soil samples collected through a sampling program supported by citizen scientists has been brought together with existing data to make the first national estimates of the surficial (top 10 cm) soil OC stock for Great British (GB) saltmarshes. To allow the inclusion of secondary data in the soil stock estimate a new bespoke organic matter to organic carbon conversion for GB saltmarsh soil was developed allowing organic matter data measured using loss-on-ignition to be convert to organic carbon content. The total GB surficial soil OC stock is 2.320 ± 0.470 Mt; English saltmarshes hold 1.601 ± 0.426 Mt OC, Scottish saltmarshes hold 0.368 ± 0.091 Mt OC, and Welsh saltmarshes hold 0.351 ± 0.082 Mt OC. The stocks were calculated within a Markov Chain Monte Carlo framework allowing robust uncertainty estimates to be derived for the first time. Spatial mapping tools are available to accompany these stock estimates at individual saltmarsh habitats throughout GB. This data will aid in the protection and management of saltmarshes and represents the first steps towards the inclusion of saltmarsh OC in the national inventory accounting of blue carbon ecosystems.

Relationship of Sphaeroma quoianum to sediment characteristics and invertebrate community

Many important wetland functions are tied to sediment dynamics, which are influenced by infaunal invertebrate communities. These communities are sensitive to changes in sediment structure and to colonization by non-native species. In a southern California salt marsh, the non-native isopod Sphaeroma quoianum has created dense networks of burrows within the marsh banks. Since this isopod increases erosion in many areas and can change local invertebrate communities, its possible contribution to habitat loss in this already-scarce southern California ecosystem is an important issue. To determine the relationship of S. quoianum to invertebrate community and sediment characteristics, three burrowed transects and one unburrowed transect were surveyed and sampled for invertebrate and sediment cores. This study tested the association between burrows and grain size distribution, sediment carbon content, respiration rates, and invertebrate community composition. Sphaeroma quoianum burrows were correlated with altered invertebrate community composition, decreased carbon content, and steep marsh bluffs. These results highlight the potential susceptibility of salt marsh habitat with steep edges to invasion by non-native species. These results also suggest that S. quoianum invasion of salt marsh habitats can alter native communities and ecosystem functions; thus, incipient invasions should be of concern to managers and ecologists alike.

Responses of leaf functional traits of clonal plant Phragmites australis to heterogeneous environments

The spatial variation of leaf functional traits in Phragmites australis could reflect the changes of resource allocation. The coupling relationship between leaf functional traits and soil environmental factors represents the ecological adaptation strategies of clonal plants to heterogeneous environments. The research object clonal plant, P. australis, was selected from an inland wetland in northwest China. We examined leaf functional traits of P. australis and their responses to soil environmental factors in wetland, salt marsh, and desert habitats. The results showed that from wetland to desert habitat, foliar contents of C, N and P decreased by 7.2%, 40.0% and 64.1%, respectively, and N and P use efficiency increased, leaf length, leaf width, leaf area, leaf dry weight, specific leaf area and leaf thickness showed a decreasing trend. The coevolution of leaf functional traits was observed, indicating a significant correlation between leaf nutrient elements and specific leaf area. Soil bulk density, salinity, and water availability were the most important environmental factors driving the variation of leaf functional traits of P. australis in wetland, salt marsh and desert habitats, respectively.

Evaluating the Performance of High Spatial Resolution UAV-Photogrammetry and UAV-LiDAR for Salt Marshes: The Cádiz Bay Study Case

Salt marshes are very valuable and threatened ecosystems, and are challenging to study due to their difficulty of access and the alterable nature of their soft soil. Remote sensing methods in unmanned aerial vehicles (UAVs) offer a great opportunity to improve our knowledge in this type of complex habitat. However, further analysis of UAV technology performance is still required to standardize the application of these methods in salt marshes. This work evaluates and tunes UAV-photogrammetry and UAV-LiDAR techniques for high-resolution applications in salt marsh habitats, and also analyzes the best sensor configuration to collect reliable data and generate the best results. The performance is evaluated through the accuracy assessment of the corresponding generated products. UAV-photogrammetry yields the highest spatial resolution (1.25 cm/pixel) orthomosaics and digital models, but at the cost of large files that require long processing times, making it applicable only for small areas. On the other hand, UAV-LiDAR has proven to be a promising tool for coastal research, providing high-resolution orthomosaics (2.7 cm/pixel) and high-accuracy digital elevation models from lighter datasets, with less time required to process them. One issue with UAV-LiDAR application in salt marshes is the limited effectiveness of the autoclassification of bare ground and vegetated surfaces, since the scattering of the LiDAR point clouds for both salt marsh surfaces is similar. Fortunately, when LiDAR and multispectral data are combined, the efficiency of this step improves significantly. The correlation between LiDAR measurements and field values improves from R2 values of 0.79 to 0.94 when stable reference points (i.e., a few additional GCPs in rigid infrastructures) are also included as control points. According to our results, the most reliable LiDAR sensor configuration for salt marsh applications is the nadir non-repetitive combination. This configuration has the best balance between dataset size, spatial resolution, and processing time. Nevertheless, further research is still needed to develop accurate canopy height models. The present work demonstrates that UAV-LiDAR technology offers a suitable solution for coastal research applications where high spatial and temporal resolutions are required.

Floristic diversity and vegetation of the az Zakhnuniyah Island, Arabian Gulf, Saudi Arabia

Islands are broadly recognized as hotspots of ecology, biological and geophysical diversity with unique plant species. The present study aimed to address the floristic composition in the Az Zakhnuniyah Island along the Arabian Gulf of Saudi Arabia. A total of 21 quadrats, of 100 m2 each were sampled, and both relative density and cover were determined. Classification (Agglomerative Hierarchical Clustering {AHC} and ordination [Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA)] were applied to identify vegetation clusters and their correlation to the underlying soil factors. Fifty plant species belonging to 21 families were recorded. Amaranthaceae (22.9%), Poaceae (12.5%), Asteraceae and Zygophyllaceae (8.33% each) were the largest represented families. Therophytes and chamaephytes were the most represented life-forms, indicating saline-desert vegetation. Most of the surveyed plant species are used for medicinal purposes and grazing. AHC and DCA allowed identifying three vegetation clusters within three distinct habitats: cluster (A): Halopeplis perfoliata- Suaeda vermiculata in wet salt-marsh habitat, cluster (B): Limonium axillare- Zygophyllum mandaville in sabkha, and cluster (C): Heliotropium bacciferum- Panicum turgidum in sand dune habitat within the island. The CCA results imply strong relationships between floristic composition and salinity measures (CaCO3, electric conductivity, Mg+2, Na+, K+, Cl− and SO4) and soil texture. The current vegetation pattern in Zakhnuniyah Island reflects a salinity gradient with variations in soil texture. Knowledge of the floristic composition and its correlation to the environmental factors within islands should guide future conservation strategy and management efforts.

Blue carbon and nutrient stocks in salt marsh and seagrass from an urban African estuary

Halophytes in estuaries are effective sinks of carbon, nitrogen, and phosphorus. Blue carbon (BC) is carbon stored in coastal habitats such as mangroves, salt marshes and seagrass. The objectives of this study were to firstly assess the biomass and sediment C stocks in salt marsh (Spartina maritima and Salicornia tegetaria) and seagrass (Zostera capensis) habitats of the Swartkops Estuary, South Africa. Secondly, we applied the nutrient pollutant indicator (NPI) to assess the nutrient status of the estuary. Six replicate sediment cores of 1 m (summer) and 0.5 m (winter) per plant species were collected at six sites. Six replicates for biomass of each species were harvested at each site during summer and winter. Biomass and nutrient dynamics showed that there were distinct seasonal differences in the magnitude of C, N, and P stored in the plants. The sediment was the dominant C pool and differed spatially with creek sites storing more C. Out of the three species, S. maritima stored the most C (224 ± 19.1 Mg C ha−1 in sediment, 16.7 ± 1.2 Mg C ha−1 in biomass), followed by S. tegetaria (207 ± 3.5 Mg C ha−1 in sediment, 4.3 ± 0.4 Mg C ha−1 in biomass) and Z. capensis (180 ± 18.4 Mg C ha−1 in sediment, 2.1 ± 0.7 Mg C ha−1 in biomass). The N:biomass ratios were low in both seasons for Z. capensis, S. maritima and S. tegetaria (0.08, 0.02 and 0.04, respectively) indicating consistent eutrophic conditions in the estuary. Resultantly, the plants displayed a significantly lower below-ground standing biomass highlighting the potential variations of BC storage in eutrophic estuaries.

Valuing the contribution of estuarine habitats to commercial fisheries in a seagrass-dominated estuary

Estimating the economic value of ecosystem services derived from estuarine habitats is important for prioritising management, conservation, and restoration activities, but remains challenging. Recently, a novel approach to estimate the value of estuarine habitats for species commercially harvested from estuaries was developed, which incorporates Bayesian stable isotope mixing models that identify the underlying primary production responsible for the nutrition of these species and links this to the value of product for fisheries. However, the difficultly of separating common primary nutrient sources in estuaries; saltmarsh grass (Sporobolus virginicus) and seagrasses, means application of this approach has been constrained to estuaries with little or no seagrass. Here, we extend this approach and examine the use of tri-variate (C, N and S) isotopic composition to model the comparative economic value of saltmarsh, seagrass, and other producer groups, for a commercial fishery. Isotope data indicated that grouped estuary producers contributed 44 ± 16% (mangrove and saltmarsh succulents), 22 ± 11% (saltmarsh grass), 11 ± 6% (fine benthic organic matter) and 23 ± 11% (seagrasses) of exploited species diets. Although seagrass and saltmarsh contributions were reasonably similar, the areal coverage of saltmarsh habitats was ∼10% that of seagrasses. This affected the area-standardised valuation of these habitats, which suggested that saltmarsh had the highest value (AUD $621 ± 191 ha−1y−1) followed by mangroves (AUD $227 ± 66 ha−1y−1), while seagrasses had the lowest value (AUD $63 ± 29 ha−1y−1). These results highlight the impact of areal coverage on the comparative value of estuarine habitats, but also highlight that habitats with lesser areal extent but higher proportional contribution to diets of exploited species may present a higher priority for conservation or repair.

Diversity and seasonal succession of resident and migratory macrobenthic fauna of saltmarsh restoration site at Sonadia Island, Cox’s Bazar, Bangladesh

The present research was carried out to assess the diversity and seasonal succession of resident and migratory fauna in the saltmarsh restoration site at Sonadia Island, Cox’s Bazar, Bangladesh. Two experimental plots (100 × 100 m 2) viz., saltmarsh restoration site (RS) and impacted site (IS) were selected in the study area for collecting resident and migratory fauna in different seasons using stratified random sampling technique. A total of 118 resident fauna of different groups were recorded from RS in different seasons whereas the total number of 54 species/taxa were recorded from the IS of saltmarsh habitat in Sonadia Island. Recorded species/taxa of RS were comprised of 8 phyla, 10 classes and 65 families where Gastropoda were consisted of 33 species, Bivalvia were 78 species, 15 species of Polychaeta, Hoplonemertea were 3 species, Holothuroidea and Pilidiophora were consisted of 2 species and also some other class: Chromadorea, Sipunculidae of 1 species. The position of Glycera sp. in the family Glyceridae of Polychaeta recorded from RS was ranked first due to their highest abundance (207 indiv./m2). Species diversity of RS were varied from 5.98 to 6.47 in different seasons. Other resident fauna of IS were under 3 phyla, 5 classes and 35 families. The phylum Mollusca contributed the highest number of species under the families Potamididae, Veneridae, Naticidae, Turritellidae, Trochidae, Arcidae and Nerillidae. Among them, Potamididae and Veneridae were the most dominant families. Migratory faunae of different finfish and shellfish (31 species) were identified from RS and IS under 11 orders and 22 families of 2 phyla during this study. Chordata and Arthropoda were the most dominant group, consisting of Chelon labrosus, Liza vaigiensis, Pomadasys argyreus, Eleutheronema tetradactylum, Platycephalus indica etc., which were also important in the saltmarsh area. Species diversity (H′ log2) of the migratory faunae were 4.34-4.58 in different seasons. From the above-mentioned result, it is indicated that the protected as well as the restored saltmarsh vegetation favors to inhabit a large number of resident fauna of diverse group, the findings of which would be very much helpful for the conservation and management of marine biodiversity to a greater extent.

Carbon accumulation and storage in a temperate coastal lagoon under the influence of recent climate change (Northwestern Adriatic Sea)

Pialassa Baiona is a shallow temperate coastal lagoon influenced by a variety of factors, including regional climate change and local anthropogenic disturbances. To better understand how these factors influenced modern organic carbon (OC) sources and accumulation rates, we measured OC as well as stable carbon isotopes (δ13C) in 210Pb-dated sediments within a vegetated saltmarsh habitat and a human impacted habitat. Relative Sea Level (RSL) at the nearby tide gauge station data and four different Sea Surface Temperature (SST) data sets were analyzed starting from 1900 to assess the potential effect of sea ingression and warming on the coastal lagoon sedimentary processes. The source contribution calculated from the MixSIAR Bayesian model revealed a mixed composition of sedimentary OC, dominated by an increase in marine-derived OC after the 1950s, matching with a decrease from autochthonous saltmarsh vegetation (Juncus spp.) in the saltmarsh habitat, and from riverine/estuarine-derived OC in the impacted habitat. RSL rise in the area (8.7 ± 0.5 mm yr−1 in the period 1900–2014) has been mainly driven by the land subsidence, especially during the central decades of the last century, enhancing the sea ingression into the lagoon. RSL rise influenced changes in sedimentary OC sources and accumulation at different level within the two habitats from the 1950s onward; conversely, no direct effect of SST was detected.

Comparison of macrobenthic communities between the invasive Spartina alterniflora and native Suaeda glauca habitats in the Yellow River Delta

Salt marsh habitats in estuaries play important roles in species compositions and macrobenthos abundances. Here, the macrobenthic communities and environmental conditions in two habitats, which are dominated by the invasive species Spartina alterniflora (SA) and native species Suaeda glauca (SG), in the Yellow River Delta (YRD) were studied to assess habitat function in four months of one year. The species diversity and abundance of macrobenthos in the SA habitat were much higher than those in the SG habitat. The taxonomic groups in the former showed significant changes over time and shifted from polychaeta (68%) in spring to mollusca (97%) in autumn, but in the latter, it was dominated by crustacea (63 ~ 86%), mollusca (1 ~ 25%) and polychaeta (9 ~ 13%), and only mollusca exhibited obvious month changes. The sediments in the SA habitat contained richer organic matter contents and exhibited higher Chl-a concentrations than those in the SG habitat, although the grain sizes were coarser in the SA habitat. Macrobenthos in the SA habitat displayed significant negative correlations with salinity and organic matter in four months. The results indicated that the taxonomic groups of macrobenthos in the SA habitat were simpler and more sensitive to environmental changes than those in the SG habitat. The effects of invasive SA on macrobenthos need to be further observed and explored, if it continues to expand in the YRD.

Inland salt marsh habitat restoration can be based on artificial flooding

Natural inland salt marshes of the temperate zone, which have been under protection for years, are still endangered and are shrinking. Unfortunately, there are not many works devoted to practical solutions to this problem in the literature. To fill this gap the article presents the results of interdisciplinary research on the reclamation of inland salt marshes on the example of a nature reserve in Central Europe. The reserve's vegetation, soil seed bank, soil, water and land geology were analysed. To reclaim the area, it was proposed using brine from a nearby health resort. This solution has been analysed in terms of salinity and sanitary safety. The results of the analyses showed that the use of brine to regularly flood the reserve's meadow should result in spontaneous restoration of the habitat rich in halophyte biodiversity. Additionally, conservation and restoration of natural saline biodiverse habitats that can be a source of new crop plants or salinity tolerance genes is important due to the growing problem of salinity in global agriculture. Therefore, presented results could inspire scientists, stakeholders and policymakers in the sustainable management of nature and human infrastructure.

Vegetation Composition of the Halophytic Grass Aeluropus lagopoides Communities within Coastal and Inland Sabkhas of Saudi Arabia.

Sabkhas are unique, highly saline ecosystems, where specially adapted plants can grow. Aeluropus lagopoides (L.) Thwaites is a halophytic forage plant growing in salt marsh habitats of inland and coastal sabkhas of Saudi Arabia. The present study provides an analysis of vegetation composition and distribution of the A. lagopoides community in five different regions within Saudi Arabia, emphasizing the environmental factors that affect species distribution. The floristic survey revealed the presence of 48 species, belonging to 26 families. Poaceae, Chenopodiaceae, Mimosaceae, Zygophyllaceae, and Asteraceae are the largest families (50% of total species). Phanerophyte, followed by chamaephytes, are the most frequent forms, indicating a typical saline desert life-form spectrum. The vegetation analysis revealed the dominance of A. lagopoides in all locations, where it was the most dominant species in Qareenah, Qaseem, and Salwa locations, and the second most dominant species in Jouf and Jizan locations. The flourishment of this halophytic grass within a wide soil range in sabkhas revealed its adaptability to the harsh environment, which could be ascribed to its structural adaptations and modifications, as well as the phenotypic plasticity. The Qareenah and Qaseem locations attained the highest species richness and evenness, while the Jizan location was the least diverse. Within the studied locations, other highly salt-tolerant species were determined with high abundances, such as Suaeda aegyptiaca (Hasselq.) Zohary, Zygophyllum album L.f., Tamarix nilotica (Ehrenb.) Bunge, Cressa cretica L., and Salicornia europaea L. The soil analysis showed a significant variation for all parameters among the studied locations, except for pH, chloride, and clay content. The Qaseem location revealed the highest values of most soil parameters, while the Jizan location showed the lowest. The canonical correspondence analysis (CCA) showed that the community structure and diversity are mainly affected by the soil salinity and moisture. Due to the economic potentialities of A. lagopoides as a forage plant and sand stabilizer, the conservation of its habitats is of vital importance. In addition, this grass could be integrated as a promising forage candidate that can be planted in saline-affected areas, even in the summer dry season.

Reliance of young sharks on threatened estuarine habitats for nutrition implies susceptibility to climate change

Climate change and urbanization of coastal areas are impacting estuarine habitats globally. While these regions are important for the early-life development of many aquatic species, links between habitat use and foraging ecology are not well known. Thus, it is essential to understand the importance of threatened habitats for animals inhabiting estuaries to promote their conservation and improve ecosystem management. This study examined the importance of estuarine habitats as feeding grounds for juvenile bull sharks (Carcharhinus leucas) in the Clarence River, a nursery area where the species is targeted by commercial fisheries in New South Wales, Australia. Juvenile sharks (n = 54) ranging from one to ∼6.5 years-old, together with particulate matter and several primary producer species of mangrove and saltmarsh, were sampled for δ13C, δ15N and δ34S stable isotopes. Bayesian mixing models and a Generalized Additive Mixed Model were used to investigate the contribution of estuarine habitats to the diet of bull sharks and changes with growth. The importance of resources consumed from within mangrove habitats for juvenile bull shark resource use was minimal but slightly increased with age, with younger sharks (<2.5 years) relying on prey feeding on sources derived from particulate organic matter, while older juveniles (4–6.5 years) preyed on species that relied mostly on threatened saltmarsh habitats. Our findings highlight the important linkages between habitats of conservation concern and species redistribution in response to climate change, particularly as the animals could be moving towards new areas lacking suitable estuarine habitats.