Mangroves reduce the vulnerability of coral reef fisheries to habitat degradation

Eco-friendly structures for sustainable mangrove restoration

Mangrove forests around the world are under significant pressure from climate change (e.g., rising sea levels), and human-related anthropogenic activities (e.g., coastal infrastructure development). Mangrove restoration projects have increased over the past decades but seedling and propagule survival rates are reportedly low, while many projects have failed. There exists a need to assess the effectiveness of sustainable and cost-effective eco-friendly structures (EFS) for advancing the success of mangrove restoration and planting activities. Herein, by EFS, we refer to the frameworks made of biodegradable materials that help overcome establishment bottlenecks and thereby boost seedling survival and growth rates. In this study, we explored the effectiveness of EFS in aiding mangrove restoration success by enhancing seedling establishment and survival and tree growth rates. Furthermore, we examine the steps involved and the challenges limiting EFS implementation in mangrove restoration projects. EFS installed in coastal areas trap sediment and may provide protection for newly planted mangrove seedlings and propagules by providing a stable anchorage and attenuating water flow and waves. Additionally, once plants are established, these biodegradable structures would decompose and add to the soil nutrients stock, thereby improving its fertility and supporting mangrove growth. We emphasize that in sites with favorable biophysical conditions for mangrove growth (hydrology, soil, topography, climate, among others), using EFS can improve mangrove restoration success by enhancing seedling establishment, survival and growth. Mangrove restoration success may have add-on benefits such as increasing the provision of related ecosystem services, blue carbon credit financing and overall coastal environmental sustainability. Given the novelness of this topic in the scientific literature, this article aims to stimulate active discussions, including anticipation of potential challenges (e.g., cost-effectiveness, ability to scale and field limitations in a range of biogeographic settings), for bringing in improvements and scalable adoption strategies to the mangrove restoration approaches under consideration.

Blue carbon ecosystems for hypoxia solution: how to maximize their carbon sequestration potential

Blue carbon refers to the carbon captured and stored by coastal and oceanic ecosystems, such as mangroves, seagrasses, and salt marshes. These ecosystems are vital for biodiversity and play a crucial role in sequestering carbon dioxide from the atmosphere, helping to mitigate climate change, which can also provide economic value by evaluating payment for ecosystem services (PES) schemes. Additionally, they help regulate dissolved organic carbon, mitigate eutrophication, and improve water quality, reducing the impact of global deoxygenation. Conserving and restoring blue carbon ecosystems are vital for mitigating hypoxia, enhancing biodiversity, and supporting various ecosystem services. Moreover, genomic research on blue carbon plants and microbes reveals adaptive traits that enhance resilience to hypoxia and environmental stress. Integrating conservation, restoration, and molecular approaches will maximize their carbon sequestration potential, ensuring ecological stability and climate adaptation. This review aims to provide an overview of blue carbon and its significance, particularly in addressing hypoxia, highlighting the critical need for investigating hypoxia responses and microbial interactions to fully understand the mechanisms of carbon sequestration and hypoxia mitigation.

Quantifying energy and nutrient fluxes in coral reef food webs

The movement of energy and nutrients through ecological communities represents the biological 'pulse' underpinning ecosystem functioning and services. However, energy and nutrient fluxes are inherently difficult to observe, particularly in high-diversity systems such as coral reefs. We review advances in the quantification of fluxes in coral reef fishes, focusing on four key frameworks: demographic modelling, bioenergetics, micronutrients, and compound-specific stable isotope analysis (CSIA). Each framework can be integrated with underwater surveys, enabling researchers to scale organismal processes to ecosystem properties. This has revealed how small fish support biomass turnover, pelagic subsidies sustain fisheries, and fisheries benefit human health. Combining frameworks, closing data gaps, and expansion to other aquatic ecosystems can advance understanding of how fishes contribute to ecosystem functions and services.

Quantifying the contribution of mangroves to local fish consumption in Indonesia: a cross-sectional spatial analysis

BACKGROUND

Indonesia has lost more mangroves than any other country. The importance of mangroves for carbon storage and biodiversity is well recognised, but much less is known about what they contribute to the communities living near them who are called on to protect them. Malnutrition in Indonesia is high, with more than a third of children stunted, partly due to poor diets. Fish are nutrient-rich and are the most widely consumed animal source food in Indonesia, making the relationship between mangroves and fish consumption of great importance. Aquaculture is also tremendously important for fish production in Indonesia and has replaced large areas of mangroves over the last two decades.

METHODS

We performed a cross-sectional, spatial analysis in this study. We combined data on fish consumption for rural Indonesian coastal households from the Indonesian National Socioeconomic Survey with spatial data on mangrove forest and aquaculture area from the Indonesian Ministry of Environment and Forestry to create a cross-sectional spatial dataset. Using a mixed-effects regression model, we estimated to what extent living in proximity to different densities of mangroves and aquaculture was associated with fresh fish consumption for rural coastal households.

FINDINGS

Our sample included 6741 villages with 107 486 households in 2008. The results showed that rural coastal households residing near high-density mangroves consumed 28% (134/477) more fresh fish and other aquatic animals, and those residing near medium-density mangroves consumed 19% (90/477) more fresh fish and other aquatic animals, than coastal households who did not live near mangroves. Coastal households that lived near high-density aquaculture consumed 2% (9/536) more fresh fish, and those that lived near medium-density aquaculture consumed 1% (3/536) less, than other rural coastal households.

INTERPRETATION

Mangroves contribute substantially to the food security and nutrition of coastal communities in Indonesia. This finding means that the conservation of mangroves is important not only for carbon storage and biodiversity, but also for the communities living near them. Aquaculture does not appear to offer similar food security benefits.

FUNDING

Bureau for Economic Growth, Education, and Environment, United States Agency for International Development.

Global rarity of intact coastal regions

Management of the land-sea interface is essential for global conservation and sustainability objectives because coastal regions maintain natural processes that support biodiversity and the livelihood of billions of people. However, assessments of coastal regions have focused strictly on either the terrestrial or marine realm. Consequently, understanding of the overall state of Earth's coastal regions is poor. We integrated the terrestrial human footprint and marine cumulative human impact maps in a global assessment of the anthropogenic pressures affecting coastal regions. Of coastal regions globally, 15.5% had low anthropogenic pressure, mostly in Canada, Russia, and Greenland. Conversely, 47.9% of coastal regions were heavily affected by humanity, and in most countries (84.1%) >50% of their coastal regions were degraded. Nearly half (43.3%) of protected areas across coastal regions were exposed to high human pressures. To meet global sustainability objectives, all nations must undertake greater actions to preserve and restore the coastal regions within their borders.

A roadmap to integrating resilience into the practice of coral reef restoration

Recent warm temperatures driven by climate change have caused mass coral bleaching and mortality across the world, prompting managers, policymakers, and conservation practitioners to embrace restoration as a strategy to sustain coral reefs. Despite a proliferation of new coral reef restoration efforts globally and increasing scientific recognition and research on interventions aimed at supporting reef resilience to climate impacts, few restoration programs are currently incorporating climate change and resilience in project design. As climate change will continue to degrade coral reefs for decades to come, guidance is needed to support managers and restoration practitioners to conduct restoration that promotes resilience through enhanced coral reef recovery, resistance, and adaptation. Here, we address this critical implementation gap by providing recommendations that integrate resilience principles into restoration design and practice, including for project planning and design, coral selection, site selection, and broader ecosystem context. We also discuss future opportunities to improve restoration methods to support enhanced outcomes for coral reefs in response to climate change. As coral reefs are one of the most vulnerable ecosystems to climate change, interventions that enhance reef resilience will help to ensure restoration efforts have a greater chance of success in a warming world. They are also more likely to provide essential contributions to global targets to protect natural biodiversity and the human communities that rely on reefs.

The Melastoma dodecandrum genome and the evolution of Myrtales

Melastomataceae have abundant morphological diversity with high economic and ornamental merit in Myrtales. The phylogenetic position of Myrtales is still contested. Here, we report the first chromosome-level genome assembly of Melastoma dodecandrum in Melastomataceae. The assembled genome size was 299.81 Mb with a contig N50 value of 3.00 Mb. Genome evolution analysis indicated that M. dodecandrum, Eucalyptus grandis and Punica granatum were clustered into a clade of Myrtales and formed a sister group with the ancestor of fabids and malvids. We found that M. dodecandrum experienced four whole-genome polyploidization events: the ancient event was shared with most eudicots, one event was shared with Myrtales, and the other two events were unique to M. dodecandrum. Moreover, we identified MADS-box genes and found that the AP1-like genes expanded, and AP3-like genes might have undergone subfunctionalization. We found that the SUAR63-like genes and AG-like genes showed different expression patterns in stamens, which may be associated with heteranthery. In addition, we found that LAZY1-like genes were involved in the negative regulation of stem branching development, which may be related to its creeping features. Our study sheds new light on the evolution of Melastomataceae and Myrtales, which provides a comprehensive genetic resource for future research.

Brazilian mangroves at risk

Abstract: Recent statements from the Brazilian federal government indicate that impacting economic activities, particularly commercial shrimp farming, are being encouraged in mangrove areas in the near future. Alterations of the National Action Plan and legal instruments that partially protected mangrove ecosystems have created an even weaker legal framework than previously existed. Such changes are leading Brazil far from the global call to conserve mangroves and from the Aichi targets and United Nations Sustainable Development Goals. Unfortunately, the loss of mangrove ecosystems and their ecosystem services will negatively impact living standards for Brazilians in coastal areas.

Human proximity suppresses fish recruitment by altering mangrove-associated odour cues

Human-driven threats to coastal marine communities could potentially affect chemically mediated behaviours that have evolved to facilitate crucial ecological processes. Chemical cues and their importance remain inadequately understood in marine systems, but cues from coastal vegetation can provide sensory information guiding aquatic animals to key resources or habitats. In the tropics, mangroves are a ubiquitous component of healthy coastal ecosystems, associated with a range of habitats from river mouths to coral reefs. Because mangrove leaf litter is a predictable cue to coastal habitats, chemical information from mangrove leaves could provide a source of settlement cues for coastal fishes, drawing larvae towards shallow benthic habitats or inducing settlement. In choice assays, juvenile fishes from the Caribbean (Belize) and Indo-Pacific (Fiji) were attracted to cues from mangroves leaves and were more attracted to cues from mangroves distant from human settlement. In the field, experimental reefs supplemented with mangrove leaves grown away from humans attracted more fish recruits from a greater diversity of species than reefs supplemented with leaves grown near humans. Together, this suggests that human use of coastal areas alters natural chemical cues, negatively affecting the behavioural responses of larval fishes and potentially suppressing recruitment. Overall, our findings highlight the critical links that exist between marine and terrestrial habitats, and the importance of considering these in the broader conservation and management of coastal ecosystems.

Dependency of Queensland and the Great Barrier Reef's tropical fisheries on reef-associated fish

Coral reefs have been subject to mass coral bleaching, potentially causing rapid and widespread degradation of ecosystem services that depend on live coral cover, such as fisheries catch. Fisheries species in tropical waters associate with a wide range of habitats, so assessing the dependency of fisheries on coral reefs is important for guiding fishery responses to coral reef degradation. This study aimed to determine how fisheries catches associate with coral reefs in Queensland, Australia. Queensland’s largest fisheries did not target fish associated with reefs, but specific sectors, particularly aquarium fisheries and commercial fisheries in the mid to northern region had a high dependence on species that use coral reefs. Regions that had a greater relative area of coral reefs had higher catches of species that depend on live coral, suggesting that coral area could be used to predict the sensitivity of a jurisdiction’s fisheries to bleaching. Dynamic analysis of stock trends found that coral trout and red throat emperor, the two largest species by catch for the reef line fishery, were at risk of overfishing if habitat loss caused declines in stock productivity. Management of fisheries that are highly dependent on reefs may need to adapt to declining productivity, but further research to support ongoing reforms in Queensland’s fisheries is needed to quantitatively link reef degradation to stock production parameters is needed.

Chromosome-scale assembly of the Kandelia obovata genome

The mangrove Kandelia obovata (Rhizophoraceae) is an important coastal shelterbelt and landscape tree distributed in tropical and subtropical areas across East Asia and Southeast Asia. Herein, a chromosome-level reference genome of K. obovata based on PacBio, Illumina, and Hi-C data is reported. The high-quality assembled genome size is 177.99 Mb, with a contig N50 value of 5.74 Mb. A large number of contracted gene families and a small number of expanded gene families, as well as a small number of repeated sequences, may account for the small K. obovata genome. We found that K. obovata experienced two whole-genome polyploidization events: one whole-genome duplication shared with other Rhizophoreae and one shared with most eudicots (γ event). We confidently annotated 19,138 protein-coding genes in K. obovata and identified the MADS-box gene class and the RPW8 gene class, which might be related to flowering and resistance to powdery mildew in K. obovata and Rhizophora apiculata, respectively. The reference K. obovata genome described here will be very useful for further molecular elucidation of various traits, the breeding of this coastal shelterbelt species, and evolutionary studies with related taxa.