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The loss and degradation of mangrove forests have triggered global restoration efforts to support biodiversity and ecosystem services, including fish stock enhancement. As mangrove restoration accelerates, it is important to evaluate outcomes for species that play functional roles in ecosystems and support services, yet this remains a clear knowledge gap. There is remarkably little information, for example, about how fish use of mangroves varies as restored vegetation matures, hampering efforts to include fisheries benefits in natural capital assessments of restoration. We used unbaited underwater cameras within two distinct zones of mangrove forests—fringe and interior—at five pairs of restored‐natural mangrove sites of increasing age from restoration in southeast Queensland, Australia. We used deep learning to automatically extract data for the four most common species: yellowfin bream (Acanthopagrus australis), sea mullet (Mugil cephalus), common toadfish (Tetractenos hamiltoni), and common silverbiddy (Gerres subfasciatus). The abundance of these species varied among sites and zones, but was equal or greater in restored sites compared to paired natural sites. Despite younger restored sites having dramatically lower structural vegetation complexity, abundances did not increase with restoration site maturity. Furthermore, while yellowfin bream and sea mullet were more abundant in the fringe zone, we observed similarities in how fish used fringe and interior zones across all sites. Our paired, space‐for‐time design provides a powerful test of restoration outcomes for fish, highlighting that even newly restored sites with immature vegetation are readily utilized by key fish species. [ABSTRACT FROM AUTHOR]

Mangroves have among the highest carbon densities of any tropical forest. These 'blue carbon' ecosystems can store large amounts of carbon for long periods, and their protection reduces greenhouse gas emissions and supports climate change mitigation. Incorporating mangroves into Nationally Determined Contributions to the Paris Agreement and their valuation on carbon markets requires predicting how the management of different land‐uses can prevent future greenhouse gas emissions and increase CO2 sequestration. We integrated comprehensive global datasets for carbon stocks, mangrove distribution, deforestation rates, and land‐use change drivers into a predictive model of mangrove carbon emissions. We project emissions and foregone soil carbon sequestration potential under 'business as usual' rates of mangrove loss. Emissions from mangrove loss could reach 2391 Tg CO2 eq by the end of the century, or 3392 Tg CO2 eq when considering foregone soil carbon sequestration. The highest emissions were predicted in southeast and south Asia (West Coral Triangle, Sunda Shelf, and the Bay of Bengal) due to conversion to aquaculture or agriculture, followed by the Caribbean (Tropical Northwest Atlantic) due to clearing and erosion, and the Andaman coast (West Myanmar) and north Brazil due to erosion. Together, these six regions accounted for 90% of the total potential CO2 eq future emissions. Mangrove loss has been slowing, and global emissions could be more than halved if reduced loss rates remain in the future. Notably, the location of global emission hotspots was consistent with every dataset used to calculate deforestation rates or with alternative assumptions about carbon storage and emissions. Our results indicate the regions in need of policy actions to address emissions arising from mangrove loss and the drivers that could be managed to prevent them. [ABSTRACT FROM AUTHOR]

Global recognition of climate change and its predicted consequences has created the need for practical management strategies for increasing the ability of natural ecosystems to capture and store atmospheric carbon. Mangrove forests, saltmarshes and seagrass meadows, referred to as blue carbon ecosystems (BCEs), are hotspots of atmospheric CO2 storage due to their capacity to sequester carbon at a far higher rate than terrestrial forests. Despite increased effort to understand the mechanisms underpinning blue carbon fluxes, there has been little synthesis of how management activities influence carbon stocks and greenhouse gas (GHG) fluxes in BCEs. Here, we present a global meta‐analysis of 111 studies that measured how carbon stocks and GHG fluxes in BCEs respond to various coastal management strategies. Research effort has focused mainly on restoration approaches, which resulted in significant increases in blue carbon after 4 years compared to degraded sites, and the potential to reach parity with natural sites after 7–17 years. Lesser studied management alternatives, such as sediment manipulation and altered hydrology, showed only increases in biomass and weaker responses for soil carbon stocks and sequestration. The response of GHG emissions to management was complex, with managed sites emitting less than natural reference sites but emitting more compared to degraded sites. Individual GHGs also differed in their responses to management. To date, blue carbon management studies are underrepresented in the southern hemisphere and are usually limited in duration (61% of studies <3 years duration). Our meta‐analysis describes the current state of blue carbon management from the available data and highlights recommendations for prioritizing conservation management, extending monitoring time frames of BCE carbon stocks, improving our understanding of GHG fluxes in open coastal systems and redistributing management and research effort into understudied, high‐risk areas. [ABSTRACT FROM AUTHOR]

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. Unlabelled Image • The Red List of Ecosystems is the global standard for assessing ecosystem collapse • The outcome for the Indian Sundarbans is Endangered, driven by historical clearing • The trend of clearing and degradation has since drastically slowed, giving cause for optimism • A novel, spatially explicit dataset indicates low levels of degradation • Ongoing threats remain, so effective management is highly pertinent [ABSTRACT FROM AUTHOR]

• We apply the Red List of Ecosystems framework to connected coastal wetlands. • Moreton Bay mangroves and seagrass were Least Concern; saltmarsh was Endangered. • Assessments of individual ecosystems can misrepresent risk of collapse. • Collapse in any one ecosystem can have seascape-wide consequences. • Integrating outcomes for connected ecosystems is thus important. 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. [ABSTRACT FROM AUTHOR]

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. • Increasingly fragmented mangrove forests were associated with higher rates of forest loss • National regulatory quality mediated how pressures and management influence mangrove loss • In nations with low regulatory quality, protected areas provide greatest benefits for mangrove protection. • Considering national variation in the effect of pressures and management actions will benefit mangrove conservation [ABSTRACT FROM AUTHOR]