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Large pelagic finfish are highly mobile, distributed across broad geographical scales, and often targeted by both commercial and recreational sectors. Fishing effort in these fisheries is variable due to seasonal patterns in fish behaviour and accessibility of fishing locations. Similarly, fisher behaviour and access are likely to differ within the recreational sector, between private boat-based fishing and charter (or for hire) fishing. Here, we compare spatio-temporal patterns in catch per unit effort (CPUE), effort (boat days) and catch (total catch per fishing party) for private boat-based and charter fishing, and identify environmental variables that may influence those patterns, for two pelagic species (the tropical narrow-barred Spanish mackerel and temperate Samson fish) in Western Australia. Spatial and temporal patterns of CPUE were investigated using geostatistical indices, such as the global and local index of collocation which compares the spatial distribution of CPUE locations across years and CPUE values at common locations respectively, and the centre of gravity which calculates the mean fishing location weighted by CPUE, along with the influence of environmental variables (including rainfall and sea surface temperature) on catch using generalised additive models (GAMs). The global index of collocation showed consistency in spatial distribution of CPUE and effort between private boat-based and charter fishing for both species. In contrast, the local index of collocation showed differences in the ranges of CPUE and effort within common locations. Private boat-based fishing often occurred close to the coast and adjacent to population centres, while charter fishing occurred further offshore. Spatial shifts over time were more prominent for Spanish mackerel with an overall northerly shift. For private boat-based fishing, higher catches of Spanish mackerel were associated with higher rainfall, along with an increase in ambient air temperature. For charter

Context: The distribution of animals is influenced by a complex interplay of landscape, environmental, habitat, and anthropogenic factors. While the effects of each of these forces on fish assemblages have been studied in isolation, the implications of their combined influence within a seascape remain equivocal. Objectives: We assessed the importance of local habitat composition, seascape configuration, and environmental conditions for determining the abundance, diversity, and functional composition of fish assemblages across a tropical seascape. Methods: We quantified fish abundance in coral, macroalgal, mangrove, and sand habitats throughout the Dampier Archipelago, Western Australia. A full-subsets modelling approach was used that incorporated data from benthic habitat maps, a hydrodynamic model, in situ measures of habitat composition, and remotely sensed environmental data to evaluate the relative influence of biophysical drivers on fish assemblages. Results: Measures of habitat complexity were the strongest predictors of fish abundance, diversity, and assemblage composition in coral and macroalgal habitats, with seascape effects playing a secondary role for some functional groups. Proximity to potential nursery habitats appeared to have minimal influence on coral reef fish assemblages. Consequently, coral, macroalgal, and mangrove habitats contained distinct fish assemblages that contributed to the overall diversity of fish within the seascape. Conclusions: Our findings underscore the importance of structural complexity for supporting diverse and abundant fish populations and suggest that the value of structural connectivity between habitats depends on local environmental context. Our results support management approaches that prioritise the preservation of habitat complexity, and that incorporate the full range of habitats comprising tropical seascapes.

Although seagrass meadows form a relatively homogenous habitat, escarpments, which form three-dimensional structures and originate from the erosion of seagrass peat, can provide important habitat for reef fishes. Here, we compare fish assemblages and habitat structural complexity among seagrass Posidonia australis escarpments and canopies, as well as limestone reef habitats, to understand the role of seagrass escarpments as reef fish habitat in Shark Bay, Western Australia. The total number of fish species, fish biomass, and top predator biomass were significantly higher in seagrass escarpments and reef habitats than in seagrass canopies due to lower habitat structural complexity and thus becoming suitable habitats for predators and prey in the latter. Both seagrass escarpment and reef habitats host similar assemblages of top predators and carnivorous fishes, such as Epinephelus coioides, Microcanthus strigatus, and Choerodon schoenleinii, that were absent in seagrass canopies. Seagrass escarpments provide an alternative habitat for reef fishes comparable to rocky reefs, which are limited in Shark Bay. Caves and ledges within the escarpments support 13.4 Mg of fish and 3.6 Mg of top predator species of commercial interest within the Shark Bay World Heritage Site. Additional research is needed to further understand the ecological importance of seagrass escarpments in enhancing fish biomass and biodiversity, as reproduction grounds or refuge from predators, and to investigate the role of meadow edges in ecosystem function.

This database contains metadata for the study sites in Serrano et al. 2023 (Ecosphere): - Latitude and longitude data for the survey transects conducted in Posidonia australis escarpments and canopies, and reef in Big Lagoon, Faure Island and Peron Peninsula in Shark Bay (Western Australia) Habitat characteristics, including abiotic factors (habitat height, cave volume, structural complexity) and biotic variables (total species, species richness, fish density, total biomass, biomass of apex predators, carnivores, hervibores, detritivores and planktivores).

Although seagrass meadows form a relatively homogenous habitat, escarpments, which form three-dimensional structures and originate from the erosion of seagrass peat, can provide important habitat for reef fishes. Here, we compare fish assemblages and habitat structural complexity among seagrass Posidonia australis escarpments and canopies, as well as limestone reef habitats, to understand the role of seagrass escarpments as reef fish habitat in Shark Bay, Western Australia. The total number of fish species, fish biomass, and top predator biomass were significantly higher in seagrass escarpments and reef habitats than in seagrass canopies due to lower habitat structural complexity and thus becoming suitable habitats for predators and prey in the latter. Both seagrass escarpment and reef habitats host similar assemblages of top predators and carnivorous fishes, such as Epinephelus coioides, Microcanthus strigatus, and Choerodon schoenleinii, that were absent in seagrass canopies. Seagrass escarpments provide an alternative habitat for reef fishes comparable to rocky reefs, which are limited in Shark Bay. Caves and ledges within the escarpments support 13.4 Mg of fish and 3.6 Mg of top predator species of commercial interest within the Shark Bay World Heritage Site. Additional research is needed to further understand the ecological importance of seagrass escarpments in enhancing fish biomass and biodiversity, as reproduction grounds or refuge from predators, and to investigate the role of meadow edges in ecosystem function.

This database contains metadata for the study sites in Serrano et al. 2023 (Ecosphere): Latitude and longitude data for the survey transects conducted in Posidonia australis escarpments and canopies, and reef in Big Lagoon, Faure Island and Peron Peninsula in Shark Bay (Western Australia) This database contains data on habitat characteristics, including abiotic factors (habitat height, cave volume, structural complexity) and biotic variables (total species, species richness, fish density, total biomass, biomass of apex predators, carnivores, hervibores, detritivores and planktivores).

Seagrass meadows provide valuable socio-ecological ecosystem services, including a key role in climate change mitigation and adaption. Understanding the natural history of seagrass meadows across environmental gradients is crucial to deciphering the role of seagrasses in the global ocean. In this data collation, spatial and temporal patterns in seagrass meadow structure, biomass and production data are presented as a function of biotic and abiotic habitat characteristics. The biological traits compiled include measures of meadow structure (e.g. percent cover and shoot density), biomass (e.g. above-ground biomass) and production (e.g. shoot production). Categorical factors include bioregion, geotype (coastal or estuarine), genera and year of sampling. This dataset contains data extracted from peer-reviewed publications published between 1975 and 2020 based on a Web of Science search and includes 11 data variables across 12 seagrass genera. The dataset excludes data from mesocosm and field experiments, contains 14 271 data points extracted from 390 publications and is publicly available on the PANGAEA® data repository (https://doi.org/10.1594/PANGAEA.929968; Strydom et al., 2021). The top five most studied genera are Zostera, Thalassia, Cymodocea, Halodule and Halophila (84 % of data), and the least studied genera are Phyllospadix, Amphibolis and Thalassodendron (2.3 % of data). The data hotspot bioregion is the Tropical Indo-Pacific (25 % of data) followed by the Tropical Atlantic (21 %), whereas data for the other four bioregions are evenly spread (ranging between 13 and 15 % of total data within each bioregion). From the data compiled, 57 % related to seagrass biomass and 33 % to seagrass structure, while the least number of data were related to seagrass production (11 % of data). This data collation can inform several research fields beyond seagrass ecology, such as the development of nature-based solutions for climate change mitigation, which include readership i

Seagrass meadows provide valuable socio-ecological ecosystem services, including a key role in climate change mitigation and adaption. Understanding the natural history of seagrass meadows across environmental gradients is crucial to deciphering the role of seagrasses in the global ocean. In this data collation, spatial and temporal patterns in seagrass meadow structure, biomass and production data are presented as a function of biotic and abiotic habitat characteristics. The biological traits compiled include measures of meadow structure (e.g. percent cover and shoot density), biomass (e.g. above-ground biomass) and production (e.g. shoot production). Categorical factors include bioregion, geotype (coastal or estuarine), genera and year of sampling. This dataset contains data extracted from peer-reviewed publications published between 1975 and 2020 based on a Web of Science search and includes 11 data variables across 12 seagrass genera. The dataset excludes data from mesocosm and field experiments, contains 14271 data points extracted from 390 publications and is publicly available on the PANGAEA® data repository (10.1594/PANGAEA.929968; Strydom et al., 2021). The top five most studied genera are Zostera, Thalassia, Cymodocea, Halodule and Halophila (84 % of data), and the least studied genera are Phyllospadix, Amphibolis and Thalassodendron (2.3 % of data). The data hotspot bioregion is the Tropical Indo-Pacific (25 % of data) followed by the Tropical Atlantic (21 %), whereas data for the other four bioregions are evenly spread (ranging between 13 and 15 % of total data within each bioregion). From the data compiled, 57 % related to seagrass biomass and 33 % to seagrass structure, while the least number of data were related to seagrass production (11 % of data). This data collation can inform several research fields beyond seagrass ecology, such as the development of nature-based solutions for climate change mitigation, which include readership interested in blue

The use of geostatistical indices to examine fishery-dependent data over time is novel. We assess the value of a range of these indices for describing trends in boat-based recreational fishing in Western Australia and areas of high effort and catches for two demersal species with varying biological characteristics, life histories and distributions. The number of blocks (10- × 10-nautical mile (~19- × 19-km) area) visited decreased by 40%, while the number of fishing trips with demersal species catch increased by 15%. Spatial indices showed a south-easterly shift in demersal catch per unit effort (CPUE) across survey years. The southerly shift of West Australian dhufish (Glaucosoma herbraicum) CPUE and subsequent return to the north likely to reflect the response of this temperate species to a marine heatwave. In comparison, CPUE of retained Baldchin groper (Choerodon rubescens) shifted north, whereas released catches shifted south with high probabilities of hotspots present associated with habitat structure. We identified hotspots of retained and released CPUE, highlighting potential areas where species experience high post-release mortality through barotrauma, and targeted spatial management strategies. Spatial indices allow quantitative definition of the structure of the fishery, identify high catch areas, and assess changes over time at a broader scale to sustainably manage multispecies fisheries.

Habitat complexity and connectivity can influence the number of species and their diversity across a landscape. For the surf zones of ocean-exposed beaches, globally one of the longest habitat interfaces, the assumed low structural complexity, and apparent homogeneity, of the sandy seafloor habitats predicts low taxonomic and functional diversity. Here, we assessed how the configuration of the seascape and the context of different beach structure functional diversity and functional niche space of fish assemblages in surf zones. We expected that beaches that were well connected with highly productive and complex estuarine and reef habitats would support a greater level of functional diversity, and a greater degree of functional complementarity within different niches. We sampled surf zones at twenty-five beaches along 50 km of coastline in southeast Queensland, Australia. We calculated functional diversity and functional niche space using variation in the functional traits of fish assemblages. We found that increased proximity with nearby subtidal rocky reefs was the key feature of the coastline shaping functional diversity and functional niche space in surf zone fishes. These effects resulted in increased functional complementarity within a number of fish functional group niches when rocky reefs were nearby. We provide empirical evidence that habitat proximity can structure functional diversity and complementarity in the surf zones of ocean beaches, a system traditionally viewed as having low habitat heterogeneity. Our results highlight the focus management must take in conserving these highly connected ecosystems to avoid negative functional consequences.

Seagrass, systems export significant amounts of their primary production as large detritus (i.e. macrophytodetritus). Accumulations of exported macrophytodetritus (AEM) are found in many areas in coastal environment. Dead seagrass leaves are often a dominant component of these accumulations, offering shelter and/or food to numerous organisms. AEM are particular habitats, different from donor habitats (i.e. seagrass meadow, kelp or macroalgae habitats) and with their own characteristics and dynamics. They have received less attention than donor habitats despite the fact they often connect different coastal habitats, are the place of intense remineralization processes and shelter associated detritus food web. As for seagrass meadows themselves, AEM are potentially affected by global change and by tropicalization processes. Here, we review briefly general characteristic of AEM with a focus on Mediterranean Sea and Western Australia and we provide some hypotheses concerning their tropicalization in a near future. We conclude that AEM functioning could change either through: (1) declines in biomass or loss of seagrass directly due to increased ocean temperatures or increased herbivory from tropicalized herbivores; (2) increased degradation and processing of seagrass detritus within seagrass meadows leading to reduced export; (3) replacement of large temperate seagrass species with smaller tropical seagrass species; and/or (4) loss or changes to macroalgae species in neighboring habitats that export detritus. These processes will alter the amount, composition, quality, timing and frequency of inputs of detritus into ecosystems that rely on AEM as trophic subsidies, which will alter the suitability of AEM as habitat and food for invertebrates.

Sandy beaches are iconic interfaces that functionally link the ocean with the land via the flow of organic matter from the sea. These cross-ecosystem fluxes often comprise uprooted seagrass and dislodged macroalgae that can form substantial accumulations of detritus, termed ‘wrack’, on sandy beaches. In addition, the tissue of the carcasses of marine animals that regularly wash up on beaches form a rich food source (‘carrion’) for a diversity of scavenging animals. Here, we provide a global review of how wrack and carrion provide spatial subsidies that shape the structure and functioning of sandy-beach ecosystems (sandy beaches and adjacent surf zones), which typically have little in situ primary production. We also examine the spatial scaling of the influence of these processes across the broader land- and seascape, and identify key gaps in our knowledge to guide future research directions and priorities. Large quantities of detrital kelp and seagrass can flow into sandy-beach ecosystems, where microbial decomposers and animals process it. The rates of wrack supply and its retention are influenced by the oceanographic processes that transport it, the geomorphology and landscape context of the recipient beaches, and the condition, life history and morphological characteristics of the macrophyte taxa that are the ultimate source of wrack. When retained in beach ecosystems, wrack often creates hotspots of microbial metabolism, secondary productivity, biodiversity, and nutrient remineralization. Nutrients are produced during wrack breakdown, and these can return to coastal waters in surface flows (swash) and aquifers discharging into the subtidal surf. Beach-cast kelp often plays a key trophic role, being an abundant and preferred food source for mobile, semi-aquatic invertebrates that channel imported algal matter to predatory invertebrates, fish, and birds. The role of beach-cast marine carrion is likely to be underestimated, as it can be consumed rapidly by highly m

Sandy beaches are iconic interfaces that functionally link the ocean with the land via the flow of organic matter from the sea. These cross-ecosystem fluxes often comprise uprooted seagrass and dislodged macroalgae that can form substantial accumulations of detritus, termed ‘wrack’, on sandy beaches. In addition, the tissue of the carcasses of marine animals that regularly wash up on beaches form a rich food source (‘carrion’) for a diversity of scavenging animals. Here, we provide a global review of how wrack and carrion provide spatial subsidies that shape the structure and functioning of sandy-beach ecosystems (sandy beaches and adjacent surf zones), which typically have little in situ primary production. We also examine the spatial scaling of the influence of these processes across the broader land- and seascape, and identify key gaps in our knowledge to guide future research directions and priorities. Large quantities of detrital kelp and seagrass can flow into sandy-beach ecosystems, where microbial decomposers and animals process it. The rates of wrack supply and its retention are influenced by the oceanographic processes that transport it, the geomorphology and landscape context of the recipient beaches, and the condition, life history and morphological characteristics of the macrophyte taxa that are the ultimate source of wrack. When retained in beach ecosystems, wrack often creates hotspots of microbial metabolism, secondary productivity, biodiversity, and nutrient remineralization. Nutrients are produced during wrack breakdown, and these can return to coastal waters in surface flows (swash) and aquifers discharging into the subtidal surf. Beach-cast kelp often plays a key trophic role, being an abundant and preferred food source for mobile, semi-aquatic invertebrates that channel imported algal matter to predatory invertebrates, fish, and birds. The role of beach-cast marine carrion is likely to be underestimated, as it can be consumed rapidly by highly m

Seagrass meadows form highly productive and diverse ecosystems that provide a range of ecosystem services along coasts of most continents (Barbier et al., 2011; Nordlund et al., 2016), yet they continue to experience large losses through direct and indirect human disturbances (Waycott et al., 2009; Duarte et al., 2018). Like other coastal ecosystems, including coral reefs and kelp forests, seagrasses are showing strong negative responses to elevated ocean temperatures and heatwaves, in which rising temperatures exceed their thresholds for survival [...].

© 2020, Coastal and Estuarine Research Federation. Spatial subsidies often occur from highly productive donor ecosystems to recipient systems with low productivity, but little is known about subsidies between highly productive ecosystems. Here, we investigated whether the kelp Ecklonia radiata, which is frequently dislodged from reefs, provides spatial subsidies in adjacent seagrass meadow where in situ productivity is already high. We clarified the pathways of the allochthonous kelp as a spatial subsidy by adding 15N-enriched kelp to Posidonia sinuosa seagrass meadows, tracing the uptake of kelp-derived nitrogen by seagrass epiphytes and epifauna. We observed a 32.5–52.2% loss of kelp biomass (wet weight), representing almost 13,000 μg of 15N from the labelled kelp. This corresponded with an increase in δ15N and 15N biomass of detritivores and epiphytes, showing either a direct or indirect (via epiphytes) assimilation of kelp-derived nutrients. The densities and biomass of the gastropod Strigosella lepidus and shrimps were higher in seagrass plots with input of E. radiata, but not for amphipods or the biomass of epiphytes. We estimate that the detritivores and epiphytes in the seagrass plots assimilated about 3% of the 15N released from the labelled kelp, and based on a data from previous study, the seagrass itself could have assimilated up to a further 6% of the released kelp 15N. Our findings show that in a highly productive seagrass ecosystem, where autochthonous food sources are available, the input of allochthonous resources such as kelp can supplement those resources and appears to play an important a role as a vector for a spatial subsidy.

Microbes are ubiquitous but our knowledge of their effects on consumers is limited in benthic marine systems. Shorelines often form hotspots of microbial and detritivore activity due to the large amounts of detrital macrophytes that are exported from other coastal ecosystems, such as kelp forests, and accumulate in these systems. Shoreline ecosystems therefore provide a useful model system to examine microbial-detritivore interactions. We experimentally test whether bacteria in the biofilm of kelp provide a bottom-up influence on growth and reproductive output of detritivores in shorelines where detrital kelp accumulates, by manipulating the bacterial abundances on kelp (Ecklonia radiata). The growth rates for both male and female amphipods (Allorchestes compressa) were greater in treatments containing bacteria than those in which bacteria were reduced through antibiotic treatment, and this effect was greater for males offered aged kelp. The proportions of ovigerous females were greater when reared on kelp with intact bacteria, indicating a more rapid reproductive development in the presence of more bacteria. Bacterial abundance had little to no influence on nutrient content and palatability of kelp, based on tissue toughness, nitrogen and carbon content and C:N ratio. Thus, the most likely pathway for a microbial effect on detritivores was through feeding on kelp-associated bacteria. Regardless of the pathway, kelp-associated microbes have a strong influence on the fitness of a highly abundant detritivore that feeds preferentially on E. radiata in shoreline systems, and therefore form a hidden trophic step in this “brown” food web and a hotspot of secondary production.

The Vasse-Wonnerup Wetland located in the South-West of Australia is recognised as a “Wetland of International Importance” under the Ramsar Convention and hosts tens of thousands of waterbirds each year. The wetland comprises the Vasse and the Wonnerup Estuaries and their exiting channels.\ Two surge barriers were constructed between the estuaries and Wonnerup Inlet at the beginning of the 20th century to prevent seawater incursion to surrounding agricultural lands. Due to nutrient enrichment and altered flows caused by river diversions and land drainage, and the surge barriers reducing flushing water flows, the system has experiences episodic algal blooms, anoxia and fish deaths. Since the late 20th century, the surge barriers have been opened in summer as part of a water management regime to allow fresh sea water input into the system to improve conditions.

© 2020, Coastal and Estuarine Research Federation. The ecological paradigm that biological interactions are more intense in the tropics than in temperate or polar regions has existed since the mid-twentieth century, but several recent meta-analyses have provided scant evidence for latitudinal gradients in the intensity of herbivory. This contradictory evidence led us to carefully review the data and results of several of those papers that failed to find latitudinal gradients in rates of seagrass herbivory. To re-evaluate the arguments around the presence or absence of latitudinal gradients in herbivory in seagrass, we began by expanding the selection criteria to include more studies to compare the published latitudinal range of seagrass occurrences with the latitudes in which seagrass herbivory has been studied. We also compared the latitudinal range of known seagrass herbivores with the distribution of studies on seagrass herbivory. Finally, we investigated studies that provided seasonal data on net primary production and standing stock of seagrasses, which allowed an assessment of the relative amounts of production that could enter the seagrass grazing food web among latitudes and climatic regimes. Consistent with recent meta-analyses, we found little latitudinal effect on grazing rates. However, we argue that the following factors are likely to confound these findings and potentially mask latitudinal trends in seagrass herbivory: (1) the paucity of data available to test latitudinal trends in grazing rates at high latitudes; (2) the mismatch between the geographic distribution of important grazers and studies on seagrass herbivory; (3) the paucity of experimental studies from areas with little or no herbivory because few researchers would initiate a study on something not observed to be occurring; (4) the high level of seasonality in seagrass production in high latitudes, where seagrass production is very low or nonexistent in winter months; (5) the fact that tem

Seagrass is recognised as an asset in the Swan Canning Riverpark, stabilising sediment and maintaining oxygen levels at the sediment/water interface. The dominant species, Halophila ovalis, is also an important food source for the iconic black swan and is thought to support diverse and productive faunal assemblages. However, much of the information about the value of this habitat is gleaned from Zostera species in estuaries elsewhere. Very little is known of the biodiversity and ecological value of Halophila, which is vastly different in shape and form to Zostera [...].

This review shows that the presence of seagrass microbial community is critical for the development of seagrasses; from seed germination, through to phytohormone production and enhanced nutrient availability, and defence against pathogens and saprophytes. The tight seagrass-bacterial relationship highlighted in this review supports the existence of a seagrass holobiont and adds to the growing evidence for the importance of marine eukaryotic microorganisms in sustaining vital ecosystems. Incorporating a micro-scale view on seagrass ecosystems substantially expands our understanding of ecosystem functioning and may have significant implications for future seagrass management and mitigation against human disturbance.

The database compiles data (used in Tarquinio et al. 2018, ISME Journal, accepted for publication) obtained from nitrogen stable isotope analysis (IRMS) and Nanoscale secondary ion mass spectrometry (NanoSIMS) of seagrass (Posidonia sinuosa) leaves and associated microorganisms. Row data (IRMS) are presented for bulk tissue 15N enrichment of P. sinuosa leaves at different times of incubation (plotted as bar chart in the manuscript), as well as the enrichment detected through the drawing of regions of interest (ROI) from NanoSIMS image analysis and plotted as box plots in the manuscript.

1. Most ecological studies require knowledge of animal abundance, but it can be challenging and destructive of habitat to obtain accurate density estimates for cryptic species, such as crustaceans that tunnel deeply into the seafloor, beaches, or mudflats. Such fossorial species are, however, widely used in environmental impact assessments, requiring sampling techniques that are reliable, efficient, and environmentally benign for these species and environments. 2. Counting and measuring the entrances of burrows made by cryptic species is commonly employed to index population and body sizes of individuals. The fundamental premise is that burrow metrics consistently predict density and size. Here we review the evidence for this premise. We also review criteria for selecting among sampling methods: burrow counts, visual censuses, and physical collections. 3. A simple 1:1 correspondence between the number of holes and population size cannot be assumed. Occupancy rates, indexed by the slope of regression models, vary widely between species and among sites for the same species. Thus, ‘average’ or ‘typical’ occupancy rates should not be extrapolated from site- or species specific field validations and then be used as conversion factors in other situations. 4. Predictions of organism density made from burrow counts often have large uncertainty, being double to half of the predicted mean value. Whether such prediction uncertainty is ‘acceptable’ depends on investigators' judgements regarding the desired detectable effect sizes. 5. Regression models predicting body size from burrow entrance dimensions are more precise, but parameter estimates of most models are specific to species and subject to site-to-site variation within species. 6. These results emphasise the need to undertake thorough field validations of indirect census techniques that include tests of how sensitive predictive models are to changes in habitat conditions or human impacts. In addition, new technologies (

Beach and coastal dune systems are increasingly subjected to a broad range of anthropogenic pressures that on many shorelines require significant conservation and mitigation interventions. But these interventions require reliable data on the severity and frequency of adverse ecological impacts. Such evidence is often obtained by measuring the response of 'indicator species'.Ghost crabs are the largest invertebrates inhabiting tropical and subtropical sandy shores and are frequently used to assess human impacts on ocean beaches. Here we present the first global meta-analysis of these impacts, and analyse the design properties and metrics of studies using ghost-crabs in their assessment. This was complemented by a gap analysis to identify thematic areas of anthropogenic pressures on sandy beach ecosystems that are under-represented in the published literature.Our meta-analysis demonstrates a broad geographic reach, encompassing studies on shores of the Pacific, Indian, and Atlantic Oceans, as well as the South China Sea. It also reveals what are, arguably, two major limitations: i) the near-universal use of proxies (i.e. burrow counts to estimate abundance) at the cost of directly measuring biological traits and bio-markers in the organism itself; and ii) descriptive or correlative study designs that rarely extend beyond a simple 'compare and contrast approach', and hence fail to identify the mechanistic cause(s) of observed contrasts.Evidence for a historically narrow range of assessed pressures (i.e., chiefly urbanisation, vehicles, beach nourishment, and recreation) is juxtaposed with rich opportunities for the broader integration of ghost crabs as a model taxon in studies of disturbance and impact assessments on ocean beaches. Tangible advances will most likely occur where ghost crabs provide foci for experiments that test specific hypotheses associated with effects of chemical, light and acoustic pollution, as well as the consequences of climate change (e.g. spec

Climate-driven changes are altering production and functioning of biotic assemblages in terrestrial and aquatic environments. In temperate coastal waters, rising sea temperatures, warm water anomalies and poleward shifts in the distribution of tropical herbivores have had a detrimental effect on algal forests. We develop generalized scenarios of this form of tropicalization and its potential effects on the structure and functioning of globally significant and threatened seagrass ecosystems, through poleward shifts in tropical seagrasses and herbivores. Initially, we expect tropical herbivorous fishes to establish in temperate seagrass meadows, followed later by megafauna. Tropical seagrasses are likely to establish later, delayed by more limited dispersal abilities. Ultimately, food webs are likely to shift from primarily seagrass-detritus to more direct-consumption-based systems, thereby affecting a range of important ecosystem services that seagrasses provide, including their nursery habitat role for fishery species, carbon sequestration, and the provision of organic matter to other ecosystems in temperate regions.

The transfer of organic material from one coastal environment to another can increase production in recipient habitats in a process known as spatial subsidy. Microorganisms drive the generation, transformation, and uptake of organic material in shallow coastal environments, but their significance in connecting coastal habitats through spatial subsidies has received limited attention. We address this by presenting a conceptual model of coastal connectivity that focuses on the flow of microbially mediated organic material in key coastal habitats. Our model suggests that it is not the difference in generation rates of organic material between coastal habitats but the amount of organic material assimilated into microbial biomass and respiration that determines the amount of material that can be exported from one coastal environment to another. Further, the flow of organic material across coastal habitats is sensitive to environmental change as this can alter microbial remineralization and respiration rates. Our model highlights microorganisms as an integral part of coastal connectivity and emphasizes the importance of including a microbial perspective in coastal connectivity studies. © 2016 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.

Drifting macrophytes consist of many species of seagrass and algae (Baring et al. 2014). During storms or large swell events, seagrass and algae are often ripped from the seafloor by hydrodynamic forcing and either float to the surface and drift, or tumble along the seafloor (Baring et al. 2014; NACC 2014a). In South West Australia, this hydrodynamic forcing typically occurs during storm events during the period late autumn to early spring (NACC 2014a). In the swash zone of sandy beaches, drifting macrophytes are pushed into the surf zone by wave, tidal and current forcing where they form dense accumulations before being washed ashore (Crawley & Hyndes 2007; Crawley et al. 2009). Drifting macrophytes may eventually be stranded on beaches and form large piles of beach-­cast wrack which can then re-­enter the surf zone with subsequent high tides (Ince et al. 2007)...

Fish faunas were sampled seasonally using a large and a small beam trawl in three seagrass habitats comprising predominantly Amphibolis griffithii or Posidonia sinuosa or Posidonia coriacea, which differ in seagrass and meadow structure. Amphibolis griffithii and P. sinuosa both produce a relatively dense leaf canopy, but the former exhibits a distinct architecture, with the leaf canopy overlying relatively open spaces surrounding woody stems, compared to the uniformly dense blade-like leaves of P. sinuosa which emerge directly from the sediment. In comparison, P. coriacea provides a landscape of patchy seagrass amongst areas of bare sand. Since the latter seagrass habitat contains large areas of sand, fish were also sampled in adjacent unvegetated areas. The number of species and density of fish were greater (P P. sinuosa than in either A. griffithii or P. coriacea. The mean number of species caught using the large trawl ranged from 16 to 24 in the first of these habitats compared to 14–21 and 9–15 in the last two habitats, respectively, and the mean densities ranged between 78 and 291 fish 1000 m−2 in P. sinuosa compared to 31–59 fish 1000 m−2 in A. griffithii and 31–59 fish 1000 m−2 in P. coriacea. The biomass of fish was greater (P P. sinuosa and A. griffithii than in P. coriacea (4.2–5.3 kg and 3.3–6.2 kg versus 0.7–1.9 kg 1000 m−2, respectively). Furthermore, the size-structure of fish differed among these habitats, where the median weight of fish was 72.1 g in A. griffithii, compared to 7.5 g and 19.8 g in P. sinuosa and P. coriacea, respectively. Ordination and ANOSIM demonstrated that the species-composition differed markedly among the three seagrass habitats (P A. griffthii is likely to allow larger fish to occupy this habitat, whereas only small fish would be able to penetrate the dense foliage of P. sinuosa. Differences in species- and size-composition of fish among these habitats may be the result of settlement-sized larvae discriminating between partic