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Predictions of the fate of coastal wetlands under the effects of sea-level rise (SLR) vary widely due to uncertainties on environmental variables, but also due to unavoidable simplifications in the models. Here, we present a simplified domain ecogeomorphic model that includes all relevant hydrodynamic, sedimentation and vegetation dynamics mechanisms that affect wetland evolution, it does not require detailed information and it is efficient enough computationally to allow the simulation of long time periods. We test this framework and apply it in different settings typically found in coastal wetlands around the world, comprising different geomorphic configurations, vegetation types, sediment characteristics and tidal regimes. Most of the wetland settings analysed are unable to cope with the high SLR rates expected by the end of the century, in agreement with results using paleo-records during periods of high SLR rates.

Models of the response of mangrove forests and saltmarshes to sea-level rise are needed to inform coastal decision making. Zero-dimensional models that simulate evolution of a point are foundational for developing spatially explicit landscape models projecting coastal wetland extents under future sea-level rise scenarios. However, both zero-dimensional and spatially explicit landscape models have suffered from insufficient calibration and inadequate validation. In this study, a zero-dimensional model framework was parameterised using real data from four sub-sites exhibiting varying rates of mineral and organic matter addition and autocompaction. The model was calibrated to correspond to tidal parameters at each sub-site and validation was undertaken across three timescales to assess model efficacy. Short-term validation encompassed the period over which measurements of surface elevation gain were determined using a network of surface elevation tables (~20 years); medium-term validation encompassed the period when higher resolution colour aerial photography was available (~35 years); and long-term validation focussed on the period of landscape evolution occurring since the mid-Holocene. The model performed well at the medium to long-term scale and was within the range of variability arising from surface elevation table measurements. This study demonstrates the critical need for site-specific data, a crucial component that is undervalued, often insufficiently resourced to generate useful data, and commonly addressed by extrapolating parameters generated from elsewhere. Validation has provided the necessary confidence for further model development at the landscape scale that will account for processes operating both vertically and laterally, such as shoreline erosion and tidal creek extension.

Climatically driven perturbations (e.g. intense drought, fire, sea surface temperature rise) can bring ecosystems that are already stressed by long-term climate change and other anthropogenic impacts to a point of collapse. Recent reviews of the responses of Australian ecosystems to climate change and associated stressors have suggested widespread ecosystem collapse is occurring across multiple biomes. Two commonly cited case studies concern forested wetland ecosystems: mangrove forest dieback in northern Australia (2015–16) and riverine forest dieback in the south-east of the continent (2002–09). We present an alternative interpretation that emphasises the dominant signal of climate change effects, rather than the interdecadal signal of climate variability that drives wetland forest dynamics. For both the south-east Australian riverine forests and mangroves of northern Australia, aerial extent remains greater after dieback than in the early 1990s. We interpret dieback and defoliation in both systems as a dry phase response and provide evidence of a current and near-future climate change trajectory of increased areal extent and cover (i.e. tree colonisation and range infilling). In both case studies, climate change-driven increases in tree cover and extent are occurring at the expense of wetland grasslands and the important ecosystem functions they support.

Long-phase (interannual) tidal cycles have been shown to influence coastal flooding and sedimentation, but their role in shaping the extent and condition of tidal wetlands has received little attention. Here, we show that the 18.61-year lunar nodal cycle, popularly termed the “lunar wobble,” is a dominant control over the expansion and contraction of mangrove canopy cover over much of the Australian continent. Furthermore, the contrasting phasing of the 18.61-year lunar nodal cycle between diurnal and semidiurnal tidal settings has mediated the severity of drought impacts in northern bioregions. Long-phase tidal cycles regulate maximum tide heights, are an important control over mangrove canopy cover, and may influence mangrove ecosystem services including forest productivity and carbon sequestration at regional scales.

Environmental flow releases in lowland Australian rivers are currently timed to avoid high-carbon production on floodplains. Moreover, return flows (water draining from floodplains back into rivers) are avoided if there exists a risk of introducing deoxygenated “blackwater” into the main channel. This concern has restricted the range of possible watering scenarios being considered by environmental flow managers. We utilised a series of blackwater flows in the lower Murrumbidgee floodplain, Australia, in 2016 and 2017 to determine the origin and trophic contribution of blackwater dissolved organic carbon (DOC) in a floodplain wetland. We demonstrate a consistent difference in the isotope signature of blackwater DOC compared to both dissolved inorganic carbon (DIC) and river water DOC, explained by the greater contribution of floodplain vegetation (including the river red gum Eucalyptus camaldulensis) to blackwater DOC. Stable carbon isotope signatures suggest a contribution of blackwater to algal production, whereby microbial-mediated conversion of blackwater DOC into DIC may create opportunities for primary autotrophic productivity. This carbon signature was incorporated by the common yabby Cherax destructor. In the main river channel, C. destructor, the native gudgeon Hypseleotris spp. and the introduced European carp Cyprinus carpio may utilise the same basal carbon source. The use of small to moderate floodplain inundation with return flow to the river, properly monitored, would ameliorate the risk of hypoxia while providing the benefit of floodplain-derived DOC and associated increases to in-stream productivity.

Observations from wetlands across the globe suggest a consistent pattern of woody encroachment into wetland grasslands, altering habitat structure and ecological function. The extent to which hydrological changes have contributed to woody invasion of wetland grasslands is unclear. Our objective was to compare rates of woody encroachment in Australian floodplain wetlands between wet and dry hydrological phases. We test the hypothesis that contraction of non-woody wetland vegetation (grasses and rushes) would be concentrated in dry phases, co-incident with recruitment of the River Red Gum Eucalyptus camaldulensis lower in the floodplain. We conduct the first detailed mapping of habitat change in two of the largest forested wetlands in inland Australia, comparing wet and dry hydrological phases. Detailed photogrammetry, supported by extensive ground survey, allowed the interpretation of high resolution aerial photography to vegetation community level. We found a consistent pattern of decline in non-woody vegetation, particularly amongst grasses utilising the C4 photosynthetic pathway. The C4 grasses Pseudoraphis spinescens and Paspalum distichum showed steep declines in the Barmah Millewa and Macquarie Marshes respectively, being replaced by River Red Gum E. camaldulensis. C3 sedges proved more resilient in both systems. Our results suggest that a pattern of tree expansion into non-woody wetland vegetation, characteristic of wetlands across the globe, is a major habitat structural change in the Australian floodplain wetlands studied. Projected hydrological impacts of climate change are likely to further restrict wetland grass foraging habitat in these semi-arid floodplain wetlands.

Much uncertainty exists about the vulnerability of valuable tidal marsh ecosystems to relative sea level rise. Previous assessments of resilience to sea level rise, to which marshes can adjust by sediment accretion and elevation gain, revealed contrasting results, depending on contemporary or Holocene geological data. By analyzing globally distributed contemporary data, we found that marsh sediment accretion increases in parity with sea level rise, seemingly confirming previously claimed marsh resilience. However, subsidence of the substrate shows a nonlinear increase with accretion. As a result, marsh elevation gain is constrained in relation to sea level rise, and deficits emerge that are consistent with Holocene observations of tidal marsh vulnerability.

Estimates of global carbon stocks in coastal wetlands reveal that these are some of the most efficient carbon‐sequestering environments in the world, which has prompted a renewed interest in conservation and restoration programs as an opportunity for greenhouse gas abatement. Accumulation of carbon in coastal wetlands is linked to diverse factors such as the type of vegetation, geomorphic setting, and sediment supply. Feedbacks between these factors and the tidal flow conditions drive the dynamics of carbon accumulation rates. Climate change‐induced sea‐level rise has been shown to increase the vulnerability to submergence of saltmarsh and mangroves in coastal wetlands, even if accommodation and landward colonization are possible. These potential losses of wetland vegetation combined with the reduced productivity of newly colonized areas will directly affect the capacity of the wetlands to sequester carbon from sediments and root growth. Here, we implement an eco‐geomorphic model to simulate vegetation dynamics, soil carbon accumulation, and changes in soil carbon stock for a restored mangrove‐saltmarsh wetland experiencing accelerated sea‐level rise. We evaluate model outcomes for existing conditions and two different management scenarios aimed at mitigating sea‐level rise effects and conserve wetland vegetation. Even though some management measures can result in partial conservation of wetland vegetation, they do not necessarily result in the best option for soil carbon capture. Our results suggest that accelerated sea‐level can trigger accelerated wetland colonization resulting in wetland areas with limited opportunities for soil carbon capture from sediment and root mineralization, an issue that has not been considered in previous studies.

The fate of coastal wetlands and their ecosystem services is dependent upon maintaining substrate elevations within a tidal frame that is influenced by sea-level rise. Development and application of morphodynamic models has been limited as few empirical studies have measured the contribution of key processes to surface elevation change, including mineral and organic matter addition, autocompaction of accumulating sediments and deep subsidence. Accordingly, many models presume that substrates are in equilibrium with relative sea-level rise (RSLR) and the composition of substrates are relatively homogenous. A 20-year record of surface elevation change and vertical accretion from a large tidal embayment in Australia coupled with analyses of inundation frequency and the character of sediments that have accumulated above mean sea level was analyzed to investigate processes influencing surface elevation adjustment. This study confirms the varying contribution of addition, decomposition and compression of organic material, and mineral sediment consolidation. Autocompaction of substrates was proportional to the overburden of accumulating sediments. These processes operate concurrently and are influenced by sediment supply and deposition. Vertical accretion was linearly related to accommodation space. Surface elevation change was related to vertical accretion and substrate organic matter, indicated by carbon storage above mean sea level. Surface elevation change also conformed to models that initially increase and then decrease as accommodation space diminishes. Rates of surface elevation change were largely found to be in equilibrium with sea-level rise measured at the nearest tide gauge, which was estimated at 3.5 mm y–1 over the period of measurements. As creation of new accommodation space with sea-level rise is contrary to the longer-term history of relative sea-level stability in Australia since the mid-Holocene, striking stratigraphic variation arises with deeper sediments dominated by mineral sands and surficial sediments increasingly fine grained and having higher carbon storage. As the sediment character of substrates was found to influence rates of surface elevation gain, we caution against the unqualified use of models derived from the northern hemisphere where substrates have continuously adjusted to sea-level rise and sediment character is likely to be more homogenous.

Background Globally, food provenance has become a concern for government authorities, the seafood industry and consumers due to increasing food safety and authenticity requirements. Wild-catch fisheries and aquaculture are both important industries; aquaculture is seen as an opportunity to strengthen food security for the growing global population. However, unregulated aquaculture can expose consumers to health risks from pathogens, antibiotics and banned chemicals. Consumers and retailers, and the reputation of the global seafood industry, is affected by food fraud through species substitution and the exchange of aquaculture produce with wild-caught product and vice versa. To ensure consumer confidence and to allow authorities to effectively enforce regulations and contain risks, methods to determine the species, production methods and geographic origin of seafood need to be readily available. Scope and approach This review summarises the currently available and emerging methodologies to determine the provenance and authenticity of seafood. The main focus of this review is to give an overview of the methods that could potentially be used by authorities to enforce regulations and to contain risks, and for the seafood industry to self-regulate and protect itself from food fraud. Key findings and conclusions The most common methods used are DNA profiling, fatty acid profiling, different methods of inductively coupled plasma spectrometry and stable isotope analysis. Additionally, methods such as blockchain, radio frequency identification and x-ray fluorescence through Itrax are currently being tested for their effectiveness in determining seafood provenance. However, these methods have drawbacks and it is likely that a combination of methods would be best suited to determine the provenance of seafood considering its complex supply chain.

For sustaining ecosystem functions and services, environmental conservation strategies increasingly target to maintain the multiple facets of biodiversity, such as functional diversity (FD) and phylogenetic diversity (PD), not just taxonomic diversity (TD). However, spatial mismatches among these components of biodiversity can impose challenges for conservation decisions. Hence, understanding the drivers of biodiversity is critical. Here, we investigated the global distribution patterns of TD, FD, and PD of breeding Anatidae. Using null models, we clarified the relative importance of mechanisms that influence Anatidae community. We also developed random forest models to evaluate the effects of environmental variables on the Anatidae TD, FD, and PD. Our results showed that geographical variation in Anatidae diversity is hemispheric rather than latitudinal. In the species‐rich Northern Hemisphere (NH), the three diversity indices decreased with latitude within the tropical zone of the NH, but increased in the temperate zone reaching a peak at 44.5–70.0°N, where functional and phylogenetic clustering was a predominant feature. In the Southern Hemisphere (SH), Anatidae diversity increased poleward and a tendency to overdispersion was common. In NH, productivity seasonality and temperature in the coldest quarter were the most important variables. Productivity seasonality was also the most influential predictor of SH Anatidae diversity, along with peak productivity. These findings suggested that seasonality and productivity, both consistent with the energy‐diversity hypothesis, interact with the varying histories to shape the contrasting hemispheric patterns of Anatidae diversity. Phylogenetic diversity (PD) and FD underdispersion, widespread across the species‐rich, seasonally productive mid‐to‐high latitudes of the NH, reflects a rapid evolutionary radiation and resorting associated with Pleistocene cycles of glaciation. The SH continents (and southern Asia) are characterized by a widespread tendency toward PD and FD overdispersion, with their generally species‐poor communities comprising proportionately more older lineages in thermally more stable but less predictably productive environments.

Mangrove ecosystems store large quantities of organic carbon for long periods of time. This study explores organic carbon stock change through the first comparative study of radiometric analysis and repeat field measures over a multi-decadal period in a mangrove system. Examining one tall gallery forest of Avicennia marina, and an adjacent interior scrub mangrove of mixed Avicennia marina and Aegiceras corniculatum, radiometric analysis estimated a soil organic carbon accumulation rate of 4.3 ± 0.6 Mg C ha−1 y−1 in the tall gallery forest and 2.2 ± 0.5 Mg C ha−1 y−1 in a stunted mangrove. Repeat measures of root carbon separated by 30 years estimated an increase of 5.06 Mg C ha−1 y−1 in the tall forest and 6.63 Mg C ha−1 y−1 in the stunted forest—suggesting an underestimate of carbon accumulation by radiometric dating of 15% and 67% in the tall and stunted forest, respectively. A higher carbon stock in the interior forest was attributed to root mass increase, associated with landward mangrove encroachment. Extrapolated to the entire region of NSW we estimate that mangrove encroachment has contributed at least about 1.8 Tg C sequestration over the 70 years for which this has been observed in New South Wales, Australia.

Assessing large scale plant productivity of coastal marshes is essential to understand the resilience of these systems to climate change. Two machine learning approaches, random forest (RF) and sup...

Dryland wetlands receiving periodical floods are of key importance for ecological resilience. The inundation regime (i.e., frequency, duration, depth, and timing of inundation), is one of the major factors that determine the suitability of local conditions for specific wetland species. During droughts, inundation conditions can reach a threshold after which wetland vegetation could transition to dryland vegetation. This study analyses the response of vegetation to hydrologic variability in an arid wetland in Australia over a period of 22 years (including the Millennium drought) in order to identify inundation thresholds for transitions. We use numerical modelling, field observations and remote sensing data to relate continuous detailed simulations of the inundation regime with the response of patches of Common reed, Water couch and River red gum, three key vegetation associations in the study site. We focus in patches that were affected by the drought and presented dryland vegetation invasion as well as reference patches that remained healthy throughout the drought. On each patch, we compare annual and inter-annual simulated inundation regimes to the minimum inundation conditions that can support the specific vegetation, and we compute the percentage area of the patch that verifies minimum inundation for each year. We define this area percentage as minimum inundation index. This index is analysed in conjunction with Landsat derived information on green vegetation coverage (green Seasonal Fractional Cover) for the selected patches. We found that the minimum inundation index and inter annual frequency are able to describe the vegetation dynamics of the patches, which can be characterised by two distinct response modes that depend on a threshold value of the minimum inundation index. Inundation below the threshold noticeably leads to degraded vegetation, but the vegetation can recover quickly if this threshold is later maintained for one or two years. Values below the threshold for more extended periods (drought) result in a gradual decrease of wetland vegetation to almost complete disappearance after four years and subsequent dryland vegetation invasion.

The accelerated rate of human‐induced environmental change poses a significant challenge for wildlife. The ability of wild animals to adapt to environmental changes has important consequences for their fitness, survival, and reproduction. Behavioural flexibility, an immediate adjustment of behaviour in response to environmental variability, may be particularly important for coping with anthropogenic change. The main aim of this study was to quantify the response of two wintering goose species (bean goose Anser fabalis and lesser white‐fronted goose Anser erythropus) to poor habitat condition at population level by studying foraging behaviour. In addition, we tested whether behavioural plasticity could alter trophic niche. We characterised foraging behaviours and calculated daily home range (HR) of the geese using global positioning system tracking data. We calculated standard ellipse areas to quantify niche width using the δ¹³C and δ¹⁵N values of individual geese. We linked behavioural plasticity with habitat quality using ANCOVA (analysis of covariance) models. We also tested the correlation between standard ellipse areas and HR using ANCOVA model. We found significant differences in geese foraging behaviours between years in their daily foraging area, travel distance and speed, and turning angle. Specifically, the birds increased their foraging area to satisfy their daily energy intake requirement in response to poor habitat conditions. They flew more sinuously and travelled faster and longer distances on a daily basis. For the endangered lesser white‐fronted goose, all behaviour variables were associated with habitat quality. For bean goose, only HR and turning angle were correlated with habitat quality. The birds, especially the lesser white‐fronted goose, may have had a higher trophic position under poor conditions. Our findings indicate that wintering geese showed a high degree of behavioural plasticity. However, more active foraging behaviours under poor habitat condition did not lead to a broader trophic niche. Habitat availability could be responsible to the divergent responses of foraging HR and isotopic niche to human‐induced environmental change. Therefore, maintaining natural hydrological regimes during the critical period (i.e. September–November) to ensure that quality food resources are available is central to the future of populations of geese within the East Asian–Australasian Flyway.

Demand for seafood, farmed or wild-caught, is growing globally. Consequently, seafood provenance is increasingly important to regulatory bodies, market chain actors and consumers. The limitations of current seafood provenance methods can be overcome using complementary or standalone nuclear techniques. This study focuses on determining the production method and geographic origin of Asian seabass (Lates calcarifer) using Stable Isotope Analysis (SIA) and X-ray fluorescence (XRF) through Itrax. The data were analysed using three different statistical methods; univariate and multivariate analysis, randomForest and LDA. The SIA model had accuracy of 84% when distinguishing the production methods and geographic origin of the L. calcarifer. The model using elemental analysis from the XRF returned an accuracy of 72%, and a combined SIA and elemental model was 81% accurate in determining provenance. However, the SIA model had two incorrect predictions compared to one incorrect prediction in the elemental model, while the combined model had no incorrectly predicted samples. The results of this study highlight that a combination of both SIA and elemental profiling through Itrax is ideal for seafood provenance.

There is a growing interest in how the management of ‘blue carbon’ sequestered by coastal wetlands can influence global greenhouse gas (GHG) budgets. A promising intervention is through restoring tidal exchange to impounded coastal wetlands for reduced methane (CH4) emissions. We monitored an impounded wetland’s GHG flux (CO2 and CH4) prior to and following tidal reinstatement. We found that biogeochemical responses varied across an elevation gradient. The low elevation zone experienced a greater increase in water level and an associated greater marine transition in the sediment microbial community (16 S rRNA) than the high elevation zone. The low elevation zone’s GHG emissions had a reduced sustained global warming potential of 264 g m−2 yr−1 CO2-e over 100 years, and it increased to 351 g m−2 yr−1 with the removal of extreme rain events. However, emission benefits were achieved through a reduction in CO2 emissions, not CH4 emissions. Overall, the wetland shifted from a prior CH4 sink (−0.07 to −1.74 g C m−2 yr−1) to a variable sink or source depending on the elevation site and rainfall. This highlights the need to consider a wetland’s initial GHG emissions, elevation and future rainfall trends when assessing the efficacy of tidal reinstatement for GHG emission control.

Coastal wetlands (mangrove, tidal marsh and seagrass) sustain the highest rates of carbon sequestration per unit area of all natural systems1,2, primarily because of their comparatively high productivity and preservation of organic carbon within sedimentary substrates3. Climate change and associated relative sea-level rise (RSLR) have been proposed to increase the rate of organic-carbon burial in coastal wetlands in the first half of the twenty-first century4, but these carbon–climate feedback effects have been modelled to diminish over time as wetlands are increasingly submerged and carbon stores become compromised by erosion4,5. Here we show that tidal marshes on coastlines that experienced rapid RSLR over the past few millennia (in the late Holocene, from about 4,200 years ago to the present) have on average 1.7 to 3.7 times higher soil carbon concentrations within 20 centimetres of the surface than those subject to a long period of sea-level stability. This disparity increases with depth, with soil carbon concentrations reduced by a factor of 4.9 to 9.1 at depths of 50 to 100 centimetres. We analyse the response of a wetland exposed to recent rapid RSLR following subsidence associated with pillar collapse in an underlying mine and demonstrate that the gain in carbon accumulation and elevation is proportional to the accommodation space (that is, the space available for mineral and organic material accumulation) created by RSLR. Our results suggest that coastal wetlands characteristic of tectonically stable coastlines have lower carbon storage owing to a lack of accommodation space and that carbon sequestration increases according to the vertical and lateral accommodation space6 created by RSLR. Such wetlands will provide long-term mitigating feedback effects that are relevant to global climate–carbon modelling. Wetlands exposed to rapid sea-level rise over the late Holocene contain more soil carbon than those that experienced a long period of sea-level stability.

Climate change adaptation options for natural systems are particularly challenging in high density urban settings. We model the vulnerability of estuarine vegetation (mangroves, saltmarshes and Casuarina forest) to sea-level rise in Australia’s most populous city, Sydney, and conduct a detailed assessment of impacts and adaptation options for a densely urbanised estuary, the Cooks River. Our modelling demonstrates a range of opportunities for the preservation and, in some cases, expansion of estuarine vegetation area under sea-level rise, though this is largely dependent on the degree of flexibility applied in the management of existing open space. Mangrove area increases under a high sea-level rise scenario, more so than under a low sea-level rise scenario, due to opportunities for landward colonisation. However, this would require estuarine vegetation expansion and land-use conversion of recreational, industrial or private land. Sediment nourishment emerges as a potentially cost-efficient means of preserving wetlands. The mix of wetland types is likely to change without active management, with higher proportion of mangrove and substantially less saltmarsh under all scenarios. Implementation of living shorelines, as opposed to hard defensive structures, could be incentivised. This could be achieved by planning concessions, ‘payment for ecosystem services’ such as managing ‘blue carbon’ values, and zoning controls that promote visual amenity and ecological adaptation.

Global demand for seafood is rising, with a commensurate increase in supply from farmed and wild-caught products. Determining seafood provenance is important to reduce food fraud, and food safety and biosecurity risks. DNA and fatty acid profiling cannot independently distinguish between farmed, wild-caught and geographic origins of seafood. This study applied stable isotope analysis (SIA) and X-ray fluorescence (XRF), using Itrax, to test their effectiveness as tools to distinguish the origin and production methods of black tiger prawns (Penaeus monodon) from a range of Asia-Pacific locations. Isotopic and elemental data (31 elements) were analysed using multivariate methods, linear discriminant analysis (LDA), and randomForest. LDA and randomForest had consistent results: XRF effectively distinguished the production method and geographic origin of P. monodon (up to 100% accuracy), while SIA had a lower accuracy (up to 95% accuracy). However, SIA and XRF are effective complementary methods for determining provenance of black tiger prawns.

A study of reproductive phenology and reproductive performance of the mangrove species Rhizophora stylosa was conducted in three estuaries spanning the southernmost 265 km of its known range on the east Australian coast. The timing of reproductive primordia, buds, flowers, fruit and propagule fall did not differ significantly over the latitudinal range of the study. Peak propagule fall occurred in April after a mean 19–20 months of development, only slightly longer than accounts for tropical latitudes. On average, 2.1% of buds matured to form viable propagules, with an average of 17.2% of buds becoming advanced fruit and 11.9% of advanced fruit becoming mature propagules, which compares well with the ranges published accounts for Australian tropical R. stylosa trees. However, there were relatively few buds per inflorescence on recorded shoots in this study, although formal studies on this in the tropics are absent. Within-site variation in bud and propagule production per shoot was greater than variability between sites in many cases, though our sample size was necessarily low due to the rarity of the trees at the southern limit and the detailed recording method. The species reproduces successfully at its known southern limit, with notable comparability to the eastern Australian Tropics. This suggests there is little thermal limitation on reproduction at the southern limit, where there is evidence of slow spread. “Precocious” reproduction as observed for young R. mangle at range limits in North America was not detected.

The centres of mangrove biodiversity and productivity have been under-represented in studies of fish diet and habitat utilization, particularly in relation to environmental changes between wet and dry seasons. Feeding habits of five dominant fish species (Thryssa kammalensis, Ambassis gymnocephalus, Escualosa thoracata, Stolephorus baganensis and Johnius belangerii) were investigated from two sites in the Matang Mangrove ecosystem, Perak Malaysia, with sampling encompassing both wet and dry seasons. The stomach fullness of the fish was on average significantly higher in the wet season (48%) than in the dry season (32%) with isopods and copepods forming a more important component of the fish diet during the wet season than the dry season. The stomach contents of each species were, on average: T. kammalensis {(Animal based (A) = 50.11%, Plant based (P) = 38.24%)}, A. gymnocephalus (A = 50.35%, P = 37.99%), E. thoracata (A = 42.09%, P = 44.4%), S. baganensis (A = 38.17%, P = 46.55%) and J. belangerri (A = 25.35%, P = 58.86%). Therefore, all five fish species can be considered omnivorous. The similarity among diets varied from 60-80% during the wet and dry season. During the dry season, stable carbon and nitrogen isotope values of the samples had less variation, indicating narrow dietary sources compared to the wet season where the distribution of their isotopic values was larger. Seasons should be considered for planning mangrove management, as results of this study found contracted trophic breadth for commercially valuable fish in the dry season.

The vulnerability of the world’s tidal marshes to sea-level rise threatens their substantial contribution to fisheries, coastal protection, biodiversity conservation and carbon sequestration. Feedbacks between relative sea-level rise (RSLR) and the rate of mineral and organic sediment accumulation in tidal wetlands, and hence elevation gain, have been proposed to ameliorate this risk. Here we report on changes in tidal marsh elevation and shoreline position in relation to our network of 387 fixed benchmarks in tidal marshes on four continents measured for an average of 10 years. During this period RSLR at these marshes reached on average 6.6 mm yr-1, compared to 0.34 mm yr-1 over the past millenia. While the rate of sediment accretion corresponded to RSLR, the loss of elevation to shallow subsidence increased in proportion to the accretion rate. This caused a deficit between elevation gain and RSLR which increased consistently with the rate of RSLR regardless of position within the tidal frame, suggesting that long-term in situ tidal marsh survival is unlikely. While higher tidal range (>3m) conferred a greater stability in measures of shoreline change and vegetation cover, other regions showed a tendency towards instability and retreat.

The resilience of coastal wetlands in the fate of sea-level rise is proposed to be related to the combined influence of changes in substrate organic matter volume, mineral sediment volume, auto-compaction of accumulating material and deep subsidence; however, relatively few studies have measured all of these variables. In addition, there is ongoing debate about the suitability of this data for modelling the behaviour of coastal wetlands under anticipated sea-level rise projections as temporal discrepancies in the elevation response of coastal wetlands derived from observational and stratigraphic records exist. To resolve these issues, data derived from a range of techniques sensitive to changes occurring at annual, decadal and century timescales, is presented in the context of available accommodation space, that is, the space in which tidally-borne material can accumulate. Focussing on an embayment in Victoria, Australia, analyses confirm that at annual-decadal timescales, organic matter behaves like a sponge, compressing as the overburden of material accumulates, resulting in auto-compaction that modulates the degree of surface elevation change that occurs as tidally-borne material accumulates. These processes operate concurrently and are influenced by sediment availability, yet vary on the basis of available accommodation space. At longer timescales, the influence of auto-compaction diminishes as organic matter has undergone significant compression and decomposition, yet accumulated material remains proportional to available accommodation space. These analyses confirm that temporal discrepancies in rates of substrate elevation change can be resolved by accounting for the timescale over which processes operate and the influence of sea-level rise on available accommodation space. Accordingly, models should dynamically consider rates of surface elevation change relative to available accommodation space.

Predictions of the effects of sea-level rise over the next century on coastal wetlands vary widely due to uncertainties on environmental variables, but also due to simplifications on the simulation methodologies used. Here, we investigate how accretion and migration processes affect wetland response to sea level rise (SLR) using a computational framework that includes all relevant hydrodynamic, sediment transport and vegetation dynamics mechanisms that affect wetland evolution, and it is efficient enough computationally to allow the simulation of long time periods. We apply this framework to different settings typically found in coastal wetlands around the world, comprising different vegetation types, different sediment loads, obstructions to flow and drainage structures, both natural and man-made. We find that the vast majority of wetland settings analysed are unable to cope with high SLR rates and disappear before the end of the century. Our findings are consistent with paleo-records that indicate limits on the accretion capacity of coastal wetlands during periods of high SLR rates.

Mangroves have shifted in position on the Australian coastline in association with sea-level fluctuations associated with climate change over a range of timescales. Relative sea-level rise following the last glacial maxima has driven mangroves across shallow continental margins punctuated by periods of relative stability and mangrove development on the continental shelf. The slowing of relative sea-level rise following 8000 BP coincided with widespread mangrove development, particularly across the tropical north of the continent. The stabilization of sea level by 7000 BP and probable subsequent decline promoted the infilling of estuaries and the replacement of mangrove with upper intertidal and supratidal habitats in many estuaries. In recent decades, mangrove landward encroachment has reversed some of these longer-term trends and is expected to continue under projected trends in relative sea level. Measures of mangrove vertical accretion utilizing the surface elevation table–marker horizon technique suggest that mangroves are currently keeping pace with sea-level rise and represent an important carbon sink.

Food fraud is an economically motivated act of deception which can impact consumers and the reputation of actors along a food supply chain. Food fraud includes adulteration, substitution, mislabeling, and other actions that might reduce the quality of food, deceive consumers, and other actors in the food supply chain, while increasing financial gains for the perpetrators. These actions can harm human health, thus raising food safety concerns, as demonstrated by outbreaks of disease caused by the adulteration of food. Food fraud occurs within global and national food systems and with a complex of intersecting food supply chains and networks, food fraud is increasingly challenging to combat. Many governments now have food monitoring programs, food safety strategies, and legal instruments to minimize opportunities for food fraud. This chapter provides an overview of common acts of food fraud and discusses some of their implications. Case studies on the adulteration of infant milk powder and horse meat substitution are used to describe how acts of food fraud can be perpetuated, how technology played a role in identifying the fraud, and how governments and the public responded. The technological advances and emerging analytical methods that are critically important to face the evolving challenges of food fraud are outlined. Specifically this chapter discusses emerging technologies, advantages and limitations of DNA, fatty acid, and elemental profiling, and stable isotope analysis used as analytical tools for detecting food fraud and determining the provenance of food.