Coastal ecosystems are being restored to combat environmental degradation and biodiversity loss. Colonization of restored sites by non-habitat-forming animals improves outcomes for ecosystems and society, yet there has been no review of how animals respond to coastal restoration. Here, we extracted 5,133 response ratios from 160 studies to show how coastal ecosystem restoration benefits animals as individuals, populations, and communities. Abundances and diversity at restored sites were greater than at degraded (61% and 35%, respectively) and unstructured (42% and 37%) control sites and similar to those at natural reference sites (both within 2%). Individuals in restored sites were similar in condition to those within control and reference sites. However, responses among projects were highly variable and rarely related to restored site maturity or characteristics, presenting a challenge for predicting outcomes and highlighting the need to improve restoration techniques, monitoring, and reporting. Nevertheless, studies so far suggest coastal restoration benefits biodiversity.

Context Gaining a better understanding of the foraging ecology of green turtles (Chelonia mydas) in different regions can improve the effectiveness of conservation and management strategies for this species. New South Wales (NSW), in eastern Australia, has been identified as a region requiring improved information on foraging ecology and habitat use by green turtles. Aims The aim of this study was to use stable-isotope analyses to investigate diet composition and foraging ecology of green turtles found stranded along the NSW coastline from 2018 to 2021. Methods This study measured delta C-13, delta N-15, and delta S-34 in macrophyte (mangrove, seagrass, and algae) samples collected along the NSW coastline, between March and June 2021, and epidermis tissue from green turtles that stranded in the same region between 2018 and 2021. In addition, stable-isotope values for animals known, or expected, to be consumed by green turtles were sourced from the literature. Macrophyte stable-isotope values were mapped to display spatial variations, then combined with literature-sourced animal matter and measured epidermis isotope values into stable-isotope mixing models. Mixing models were used to determine diet structure for each stranded green turtle, and their similarity to regional macrophyte isotope values to infer potential foraging locations. Key results High variation was present in delta C-13, delta N-15, and delta S-34 values of macrophyte sources along the NSW coastline, limiting the potential to infer the recent foraging locations of stranded green turtles. High delta N-15 values in green turtle epidermis samples indicated that most sampled turtles were feeding two to three trophic levels above primary producers within algal-based food webs. Mixing models suggested that these food webs were predominantly supported by algae (mean +/- s. d. = 51.2 +/- 6.1%) and animal material (31.4 +/- 4.7%), with mangrove (13.4 +/- 2.0%) and seagrass (4.0 +/- 2.5%) representing much smaller proportions of overall diet composition. Conclusions The results showed that green turtles stranded along the NSW coastline feed primarily in algae-dominated food webs, with evidence of omnivory. These findings suggest that sampled individuals display diet compositions alternative to those of their Queensland counterparts, who feed primarily in seagrass-dominated habitats. Management and conservation programs in NSW should focus on limiting anthropogenic disturbances in algae-dominated habitats. Implications This novel finding demonstrated the importance of algae-dominated habitats for green turtle conservation and management in south-eastern Australia. The generated isoscapes are useful in examining isotopic variations in macrophytes along the NSW coastline.

Global theories of change (ToCs) can provide broad, overarching guidance for conservation and sustainable use of Earth’s ecosystems. However, broad guidance alone cannot inform how conservation actions will lead to desired socioecological outcomes. Here we develop a framework for translating a global-scale ToC into focused, ecosystem-specific ToCs that consider feasibility of actions, as determined by national socioeconomic and political contexts (that is, enabling conditions). We used coastal wetlands as a case study for developing the framework and identified six distinct multinational profiles of enabling conditions (‘enabling profiles’) for their conservation. For countries belonging to profiles with high internal capacity to enable conservation, we described plausible ToCs that involved strengthening policy and regulation. Alternatively, for profiles with low internal enabling capacity, plausible ToCs typically required formalizing community-led conservation. Our ‘enabling profile’ framework can be applied to other ecosystems to help operationalize the Kunming–Montreal Global Biodiversity Framework and meet sustainable development goals. Theories of change have been a staple of sustainability research, but how to connect such overarching concepts to actionable items can be a struggle. This study uses coastal wetlands to demonstrate a potential framework for integrating indicators of conservation enabling conditions into theories of change.

Mangrove forests support unique biodiversity and provide a suite of ecosystem services (ES) that benefit people. Decades of continual mangrove loss and degradation have necessitated global efforts to protect and restore this important ecosystem. Generating and evaluating asset maps of biodiversity and ES is an important precursor to identifying locations that can deliver conservation outcomes across varying scales, such as maximising the co-occurrence of specific ES. We bring together global datasets on mangrove-affiliated biodiversity, carbon stocks, fish and invertebrate production, and coastal protection to provide insight into potential trade-offs, synergies and opportunities from mangrove conservation. We map opportunities where high ES provision co-occurs with these areas that could be leveraged in conservation planning, and identify potential high-value opportunities for single ES that might otherwise be missed with a biodiversity focus. Hotspots of single ES, co-occurrence of multiple ES, and opportunities to simultaneously leverage biodiversity and ES occurred throughout the world. For example, efforts that focus on conserving or restoring mangroves to store carbon can be targed to deliver multiple ES benefits. Some nations, such as Vietnam, Oman, Ecuador and China, showed consistent (although not necessarily strong) correlations between ES pairs. A lack of clear or consistent spatial trends elsewhere suggests that some nations will likely benefit more from complementarity-based approaches that focus on multiple sites with high provision of different services. Individual sites within these nations, however, such as Laguna de Terminos in Mexico still provide valuable opportunities to leverage co-benefits. Ensuring that an ES focused approach is complemented by strategic spatial planning is a priority, and our analyses provide a precursor towards decisions about where and how to invest.

There is an urgent need to halt and reverse loss of mangroves and seagrass to protect and increase the ecosystem services they provide to coastal communities, such as enhancing coastal resilience and contributing to climate stability.1,2 Ambitious targets for their recovery can inspire public and private investment in conservation,3 but the expected outcomes of different protection and restoration strategies are unclear. We estimated potential recovery of mangroves and seagrass through gains in ecosystem extent to the year 2070 under a range of protection and restoration strategies implemented until the year 2050. Under a protection-only scenario, the current trajectories of net mangrove loss slowed, and a minor net gain in global seagrass extent (∼1%) was estimated. Protection alone is therefore unlikely to drive sufficient recovery. However, if action is taken to both protect and restore, net gains of up to 5% and 35% of mangroves and seagrasses, respectively, could be achieved by 2050. Further, protection and restoration can be complementary, as protection prevents losses that would otherwise occur post-2050, highlighting the importance of implementing protection measures. Our findings provide the scientific evidence required for setting strategic and ambitious targets to inspire significant global investment and effort in mangrove and seagrass conservation.

Abstract Gaining a better understanding of the foraging ecology of green turtles (Chelonia mydas) in different regions can improve the effectiveness of conservation and management strategies. New South Wales (NSW), in eastern Australia, has been identified as a region requiring improved information on foraging ecology and habitat use by green turtles. This study used stable isotope ratios of δ13C, δ15N, and δ34S from macrophytes collected along the NSW coastline from -35.722585°S, 150.230674°E through to -28.537292°S, 153.555205°E, between March- June 2021, and stored epidermis tissue from stranded green turtles found along the NSW coastline from 1998-2020. The aim of the study was to investigate diet composition and foraging behaviour of green turtles stranded along the NSW coastline. Mixing model analyses demonstrate that stranded turtles had been feeding in food-webs predominantly supported by algae (74.8%), then seagrass (19.2%), and trivial amounts of mangrove material (6%). Enriched δ15N values indicate the majority of sampled turtles feeding two to three trophic levels above primary producers within algal-based food webs. High variation was present in δ13C, δ15N, and δ34S values of macrophyte sources along the NSW coastline, limiting the potential to infer the foraging behaviour of stranded green turtles. The results show green turtles stranded along the NSW coastline feed primarily in algae-dominated food-webs, with evidence of omnivory. This novel finding demonstrates the importance of algae-dominated habitats for green turtle conservation in eastern Australia. These findings may reflect opportunistic foraging behaviour of stranded green turtles, with algae being the dominate macrophyte in NSW waters.

Vegetated coastal wetlands, including seagrass, saltmarsh and mangroves, are threatened globally, yet the need to avert these losses is poorly recognized in international policy, such as in the Convention on Biological Diversity and the United Nations (UN) Sustainable Development Goals. Identifying the impact of overlooking coastal wetlands in ecosystem assessment frameworks could help prioritize research efforts to fill these gaps. Here, we examine gaps in the recognition of coastal wetlands in globally applicable ecosystem assessments. We address both shortfalls in assessment frameworks when it comes to assessing wetlands, and gaps in data that limit widespread application of assessments. We examine five assessment frameworks that track fisheries, greenhouse gas emissions, ecosystem threats, and ecosystem services. We found that these assessments inform management decisions, but that the functions provided by coastal wetlands are incompletely represented. Most frameworks had sufficient complexity to measure wetland status, but limitations in data meant they were incompletely informed about wetland functions and services. Incomplete representation of coastal wetlands may lead to them being overlooked by research and management. Improving the coverage of coastal wetlands in ecosystem assessments requires improving global scale mapping of wetland trends, developing global-scale indicators of wetland function and synthesis to quantitatively link animal population dynamics to wetland trends. Filling these gaps will help ensure coastal wetland conservation is properly informed to manage them for the outstanding benefits they bring humanity.

Submerged aquatic vegetation (SAV; e.g. seagrasses, macroalgae), forms key habitats in shallow coastal systems that provide a plethora of ecosystem services, including coastal protection, climate mitigation and supporting fisheries production. Light limitation is a critical factor influencing the growth and survival of SAV, thus it is important to understand how much light SAV needs, and receives, to effectively assess the risk that light limitation poses. Light monitoring is commonly used to inform environmental decision making to minimise loss of SAV habitat, but the temporal and spatial extent of monitoring is often limited by cost and logistical difficulties. An ability to remotely estimate light across different locations can therefore improve the conservation and management of SAV habitats. Here we combine an extensive monitoring program with publicly available data and machine learning to develop a model that estimates the light reaching submerged seagrasses in a shallow subtropical embayment in southern Queensland, Australia. Our model accurately predicts the intensity of photosynthetically active radiation (PAR) reaching the canopy of SAV from entirely remotely available data. The best performing model predicted light intensity with >99% at the management relevant daily, and 14-day rolling average time resolutions. This model enables monitoring of light available to SAV without an ongoing need for in-water instruments, minimising cost and risk to personnel, and improving assessment speed. The technique can be applied to SAV management plans in shallow waters throughout the world, where suitable remote public data is available.

Connectivity is fundamentally important for shaping the resilience of complex human and natural networks when systems are disturbed. Ecosystem resilience is, in part, shaped by the spatial arrangement of habitats, the permeability and fluxes between them, the stabilising functions performed by organisms, their dispersal traits, and the interactions between functions and stressor types. Controlled investigations of the relationships between these phenomena under multiple stressors are sparse, possibly due to logistic and ethical difficulties associated with applying and controlling stressors at landscape scales. Here we show that grazing performance, a key ecosystem function, is linked to connectivity by manipulating the spatial configuration of habitats in microcosms impacted by multiple stressors. Greater connectivity enhanced ecosystem function and reduced variability in grazing performance in unperturbed systems. Improved functional performance was observed in better connected systems stressed by harvesting pressure and temperature rise, but this effect was notably reversed by the spread of disease. Connectivity has complex effects on ecological functions and resilience, and the nuances should be recognised more fully in ecosystem conservation.

Global-scale conservation initiatives and policy instruments rely on ecosystem indicators to track progress towards targets and objectives. A deeper understanding of indicator interrelationships would benefit these efforts and help characterize ecosystem status. We study interrelationships among 34 indicators for mangroves, saltmarsh, and seagrass ecosystems, and develop data-driven, spatially explicit typologies of coastal wetland status at a global scale. After accounting for environmental covariates and gap-filling missing data, we obtained two levels of clustering at 5 and 18 typologies, providing outputs at different scales for different end users. We generated 2,845 cells (1° (lat) × 1° (long)) globally, of which 29.7% were characterized by high land- and marine-based impacts and a high proportion of threatened species, 13.5% by high climate-based impacts, and 9.6% were refuges with lower impacts, high fish density and a low proportion of threatened species. We identify instances where specific actions could have positive outcomes for coastal wetlands across regions facing similar issues. For example, land- and marine-based threats to coastal wetlands were associated with ecological structure and function indicators, suggesting that reducing these threats may reduce habitat degradation and threats to species persistence. However, several interdimensional relationships might be affected by temporal or spatial mismatches in data. Weak relationships mean that global biodiversity maps that categorize areas by single indicators (such as threats or trends in habitat size) may not be representative of changes in other indicators (e.g., ecosystem function). By simplifying the complex global mosaic of coastal wetland status and identifying regions with similar issues that could benefit from knowledge exchange across national boundaries, we help set the scene for globally and regionally coordinated conservation.

Seagrass meadows are threatened by multiple pressures, jeopardizing the many benefits they provide to humanity and biodiversity, including climate regulation and food provision through fisheries production. Conservation of seagrass requires identification of the main pressures contributing to loss and the regions most at risk of ongoing loss. Here, we model trajectories of seagrass change at the global scale and show they are related to multiple anthropogenic pressures but that trajectories vary widely with seagrass life-history strategies. Rapidly declining trajectories of seagrass meadow extent (>25% loss from 2000 to 2010) were most strongly associated with high pressures from destructive demersal fishing and poor water quality. Conversely, seagrass meadow extent was more likely to be increasing when these two pressures were low. Meadows dominated by seagrasses with persistent life-history strategies tended to have slowly changing or stable trajectories, while those with opportunistic species were more variable, with a higher probability of either rapidly declining or rapidly increasing. Global predictions of regions most at risk for decline show high-risk areas in Europe, North America, Japan, and southeast Asia, including places where comprehensive long-term monitoring data are lacking. Our results highlight where seagrass loss may be occurring unnoticed and where urgent conservation interventions are required to reverse loss and sustain their essential services.

Monitoring of seagrass meadows is essential to inform adaptive management and address widespread declines in seagrass ecosystems. Effective monitoring techniques require sensitive indicators that are capable of detecting sub-lethal stressors and differentiating stress responses from background environmental variation. Here we explore untargeted metabolomics as a means to measure multi-parameter molecular responses of seagrass to low-light stress. We subjected Zostera muelleri to reduced light scenarios (<10% natural light) in a six-week field experiment. Biomass loss was quantified over time and leaf samples were analysed by Nuclear Magnetic Resonance (NMR) spectroscopy to explore the effect of low-light exposure on metabolic activity. We identified several potential bioindicators of low-light stress: a reduction of soluble sugars and their derivatives, glucose, fructose, sucrose and myo-inositol, N-methylnicotinamide, organic acids and various phenolic compounds, and an increase in some amino acids. These signals were evident even amongst a noisy background of environmental variation and are consistent with inhibition of photosynthesis. Metabolite profiles showed a more consistent response to low-light stress than to biomass loss. These results suggest that metabolomics measurements may be useful bio-indicators of low-light stress in seagrass and that molecular indicators could inform on management of seagrass ecosystems.

Zostera muelleri, the dominant seagrass species along the eastern coastline of Australia, has declined due to anthropogenic stressors, including reduced water clarity. Water quality has improved in recent years, but restoration efforts are hampered by limited knowledge of transplantation methods. To support future restoration efforts, we tested multiple techniques for transplanting mature seagrass shoots: (1) sediment cores with intact seagrass plants (plug); (2) individual shoots anchored on frames (frame); (3) frame methods combined with subsurface mats to exclude bioturbating animals (mat+frame); (4) above-ground cages to exclude grazing fish (cage+frame); and (5) combined treatment of above-ground cages and subsurface mats (cage+mat+frame). Transplant success over 10 months showed considerable variability among locations. At one site, seagrass persisted in all treatments, with highest growth in the mat+frame treatment. At two locations, uncaged shoots were lost within 6–35 days of transplanting, presumably due to grazing by fish. In treatments with cages, growth was again highest in the mat+frame treatment. At the fourth location, all seagrass was lost due to physical stress. Thus, we conclude that transplantation success is highest using the mat+frame technique, but overall success depends on careful assessment of biotic and abiotic stressors at the chosen locations.

Accurately evaluating ecosystem status is vital for effective conservation. The Red List of Ecosystems (RLE) from the International Union for the Conservation of Nature (IUCN) is the global standard for assessing the risk of ecosystem collapse. Such tools are particularly needed for large, dynamic ecosystem complexes, such as the Indian Sundarbans mangrove forest. This ecosystem supports unique biodiversity and the livelihoods of millions, but like many mangrove forests around the world is facing substantial pressure from a range of human activities. Holistic, standardised and quantitative environment risk assessment frameworks are essential here, because previous assessments have either been qualitative in nature, or have generally considered single threats in isolation. We review these threats and utilise the RLE framework to quantitatively assess the risk of ecosystem collapse. Historical clearing and diminishing fish populations drove a status of Endangered (range: Vulnerable to Endangered), and ongoing threats including climate change and reduced freshwater supply may further impact this ecosystem. However, considering recent change, the outlook is more optimistic. Mangrove extent has stabilised, and analysis of mangrove condition highlights that only a small proportion of the forest is degraded. Using the RLE provides an authoritative avenue for further protection and recognition of the issues facing this UNESCO World Heritage Site. We also identify knowledge and data gaps in the Sundarbans that are likely common to coastal systems globally. By articulating these and presenting opportunities and recommendations, we aim to further the conservation goals of the IUCN and the implementation of its new assessment framework.

Human-induced habitat clearing and pollution are leading drivers of biodiversity loss. Ecosystem assessments are required to identify ecosystems at risk of collapse, but they should account for cross-system linkages and dynamics where necessary. This is particularly true for coastal wetlands (e.g. seagrass, mangroves and saltmarsh), which exhibit high ecological connectivity and have individually suffered global declines over the last century. We use the coastal wetlands of Moreton Bay, Queensland, Australia, as a model system to examine how integrating outcomes of multiple, simultaneously conducted, ecosystem assessments can assist in identifying appropriate management and conservation strategies. We simultaneously conducted separate assessments of seagrass, mangrove and saltmarsh ecosystems against the IUCN Red List of Ecosystems criteria. Despite substantial human population growth in the region, seagrass and mangroves were assessed as Least Concern. Mangroves were found to be rapidly encroaching on saltmarsh. This process, together with past clearing, were the major drivers behind saltmarsh being assessed as Endangered. Given the importance of connectivity among these connected ecosystems, collapse in any one ecosystem can have seascape-wide consequences, highlighting the benefit of conducting multi-ecosystem assessments. Consequently, a fully integrated assessment of the coastal wetlands as a single entity would miss key processes, such as mangrove encroachment, potentially underestimating overall risks. Our study highlights the plight of saltmarsh and the value of conducting simultaneous RLE assessments for multiple ecosystems comprising seascapes. We recommend that connectivity be accounted for explicitly in assessments of other connected, high-risk ecosystems.

Coronavirus disease 2019 (COVID-19) is a global crisis. Severe interruptions to international trade and travel are crippling economies and forcing reevaluation of economic, health, and environmental trajectories. Given that COVID-19 has triggered widespread changes in human behavior and reductions in pollution (1, 2), it presents opportunities for further positive change. Lockdowns have spurred households to rethink consumer needs, making now an opportune time to promote sustainable consumer choices that will become more engrained with prolonged exposure (1). How we emerge from the state of lockdowns will drive a new world economy with lasting effects on global biodiversity and supply chains (3, 4).

Many ecological investigations rely on understanding the movement of animals through marine environments. Most available tracking techniques are invasive (e.g. tissue sampling) and require extensive effort and/or cost (e.g. capture-mark-recapture or satellite telemetry). The isotopic compositions of barnacle shells (δ13C and δ18O) are known to record the ambient water temperature and salinity conditions in which they grew. Thus, isotopic analysis of ‘hitchhiking’ barnacles on animals or objects has the potential to yield information about their movement between water bodies of varying isotopic properties. We present, for the first time, isotopic data for barnacle shell samples that grew on a satellite-tracked sea turtle host. The satellite telemetry record, together with documented barnacle growth rates, allowed for sequential samples from individual barnacle shells to be assigned a specific time and location for direct comparison of isotope values to environmental conditions. We developed models that allow barnacle shell δ13C and δ18O to be linked, with a high degree of predictability, to sea surface temperature (SST) and salinity (SSS). Our sea turtle case study demonstrated how these models can be used to create isoscapes, allowing hosts to be tracked in space and time at higher resolution than most attempts to use soft-tissue isotopes for a similar purpose, and at considerably lower cost than satellite telemetry. The conceptual advance presented here could be applied widely to understand the movement of any animal or object that carries hitchhiking barnacles.

The development and uptake of citizen science and artificial intelligence (AI) techniques for ecological monitoring is increasing rapidly. Citizen science and AI allow scientists to create and process larger volumes of data than possible with conventional methods. However, managers of large ecological monitoring projects have little guidance on whether citizen science, AI, or both, best suit their resource capacity and objectives. To highlight the benefits of integrating the two techniques and guide future implementation by managers, we explore the opportunities, challenges, and complementarities of using citizen science and AI for ecological monitoring. We identify project attributes to consider when implementing these techniques and suggest that financial resources, engagement, participant training, technical expertise, and subject charisma and identification are important project considerations. Ultimately, we highlight that integration can supercharge outcomes for ecological monitoring, enhancing cost-efficiency, accuracy, and multi-sector engagement.

Human activities that threaten ecosystems often vary across small spatial scales, though they can be driven by large-scale factors like national governance. Here, we use two decades of data on global mangrove deforestation to assess whether landscape-scale indirect pressures – cumulative impacts, population density, mangrove forest fragmentation, the global human footprint – and management responses (protected areas) are related to rates of mangrove loss, and whether the impacts of these activities vary by nation. By integrating rates of loss at different spatial scales into a Bayesian hierarchical model, we also assess whether national-scale patterns in mangrove loss are predicted by national regulatory quality. Globally, less fragmented forests had lower rates of mangrove loss. We observed variability among nations in the effect of pressures and management responses on mangrove loss. National regulatory quality mediated how pressures and management interact to influence mangrove loss. Protected areas had a greater benefit for slowing mangrove loss rates in countries with low, rather than high, regulatory quality, ostensibly because countries with higher regulatory quality have greater protection of mangroves outside of protected areas. High population densities were also associated with greater mangrove loss, but only in nations with low regulatory quality. We suggest that efforts to protect mangrove forests will benefit from developing solutions that consider national context and address differences in the effect of pressures and cumulative impacts. Our model can also be applied to other globally threatened ecosystems to understand how variation in local context can affect national-scale conservation outcomes.

Seascapes are typically comprised of multiple components that are functionally linked by the movement of organisms and fluxes of matter. Changes to the number and spatial arrangement of these linkages affect biological connectivity that, in turn, can alter ecological functions. Herbivory is one such function, pivotal in controlling excessive algal growth when systems become disturbed. Here, we used microcosm experiments to test how the change to connectivity affects herbivory under different levels of disturbance. We applied network theory to measure types of connectivity at different scales (patch and whole system) and quantified herbivory by a crustacean mesograzer exposed to excess algae, mimicking pulse and press disturbances. We demonstrate that greater connectivity significantly enhances herbivory in Clibanarius virescens: Both the number of linkages and their spatial arrangement interact to shape the response of herbivory in systems to disturbance. Our findings highlight the value of controlled experiments for advancing theories about the potential effects of connectivity on important ecological functions, such as herbivory, and justify further investigation to measure how connectivity might affect the resilience of ecosystems. We posit that the variation in the type, and scale, of spatial linkages might have profound consequences for managing the capacity of ecosystems to respond to disturbance.