The vital role of seagrass meadows in Pacific Island marine ecosystems

6 March 2025 - Seagrass meadows, the unsung heroes of marine ecosystems, play a crucial role in maintaining ocean health, biodiversity, and coastal resilience.

In recognition of their significance, the United Nations General Assembly adopted a resolution in May 2022, declaring 01 March as World Seagrass Day. This annual observance aims to raise awareness about seagrass conservation, aligning with global efforts to protect marine biodiversity and combat climate change.

Seagrasses, marine flowering plants found in shallow coastal waters worldwide, provide essential ecosystem services. Covering just 0.1 percent of the ocean floor, they serve as habitat and food sources for numerous marine species, including fish, seahorses, turtles, and dugongs. These underwater meadows act as natural water filters, improving water quality by removing pollutants and excess nutrients.

Additionally, seagrasses are powerful carbon sinks, capable of storing up to 18 percent of the world’s oceanic carbon, making them crucial in mitigating climate change.

Despite their critical role, seagrass ecosystems face significant threats, including coastal development, pollution, climate change, and unregulated fishing. Alarmingly, seagrass meadows have been declining globally at a rate of 7 percent per year since the 1930s. Protecting and restoring these vital ecosystems is essential for maintaining marine biodiversity, ensuring food security, and safeguarding coastal communities from the impacts of climate change.

Recognising the urgent need for action, the Management and Conservation of Blue Carbon Ecosystems in Pacific Island Countries (MACBLUE) project is working to map, assess, and conserve seagrass and mangrove ecosystems in the Pacific.

The initiative aims to provide governments with critical data to support conservation efforts, develop sustainable management strategies, and enhance community engagement in ecosystem restoration.

To gain deeper insights into the role of seagrass ecosystems and MACBLUE’s conservation efforts, Pasifika Environews interviewed Raphael Linzatti, Project Director for MACBLUE.

Raphael Linzatti, Project Director for MACBLUE Photo: Pasifika Environews

Q: Can you explain the role of seagrass meadows in carbon sequestration and how they compare to terrestrial forests in mitigating climate change?

Raphael Linzatti: Seagrass meadows are incredibly efficient carbon sinks, capturing and storing carbon at rates far higher than terrestrial forests. Though smaller in area, they sequester more carbon per unit than many land-based ecosystems, making them crucial in climate change mitigation. Their ability to trap and store carbon for millennia makes them essential to addressing the global climate crisis.

Q: What are the primary ecosystem services provided by seagrass meadows to coastal communities in Pacific Island countries, and how do they support marine biodiversity?

Linzatti: Seagrass meadows provide critical ecosystem services, including nursery grounds for fish and marine species, water filtration, and shoreline protection from erosion. They contribute to food security by sustaining fish populations, enhancing biodiversity, and storing carbon to help mitigate climate change. Additionally, they serve as vital habitats for various marine species, including fish, turtles, and dugongs. In Pacific Island ecosystems, they are especially important for sustaining fish populations, which are crucial for local food security and livelihoods. Dugongs and green turtles, in particular, depend heavily on healthy seagrass meadows for survival in countries like Vanuatu, Solomon Islands, and Papua New Guinea.

Q: Which Pacific Island countries does MACBLUE work in, and how are seagrass species protected?

Linzatti: MACBLUE works in Fiji, Papua New Guinea, Vanuatu, and the Solomon Islands. Seagrass species in these countries are protected through policy advocacy, as well as community-based management and conservation practices to ensure long-term protection. All four countries have set conservation goals for seagrass meadows in their National Biodiversity Strategies and Action Plans (NBSAPs). For example, in Papua New Guinea, the Locally Managed Marine Area Network, in partnership with local tribes, is working on seagrass conservation. In Vanuatu, the Global Environment Facility’s Dugong and Seagrass Conservation Project focuses on community-based monitoring for conservation. The government of the Solomon Islands is developing an integrated Coastal Zone Management Plan.

Q: How many seagrass species are present in these countries, and can you name them?

Linzatti: These countries host several species of seagrass, including Halodule pinifolia, Halophila ovalis, and Zostera marina. In terms of diversity, Papua New Guinea has the highest number of species (13), followed by Solomon Islands (10), Vanuatu (12), and Fiji (6).

Q: How does the MACBLUE project approach the mapping and assessment of seagrass ecosystems in its partner countries?

Linzatti: We utilise satellite data from the Digital Earth Pacific platform, supported by SPC, to map and monitor seagrass meadows. We use freely available satellite images from the European Union’s Copernicus Programme. The project works closely with local governments and stakeholders to assess the extent, health, and carbon storage potential of seagrass ecosystems, ensuring that data is locally validated and relevant to national conservation strategies.

Q: How does MACBLUE collaborate with regional organisations and governments?

Linzatti: MACBLUE collaborates with regional organisations like SPREP and SPC, as well as national governments in our four partner countries, to strengthen institutional capacity, enhance policy frameworks, and promote best practices in seagrass conservation. The project fosters partnerships that integrate science, local knowledge, and governance for sustainable ecosystem management. This year, we will implement local management projects in all four countries with the coastal communities, and the lessons learned will be used to support government policies.

Q: What challenges do seagrass ecosystems face in the Pacific, and how does MACBLUE address them?

Linzatti: Seagrass ecosystems in the Pacific face challenges such as coastal development, pollution, and destructive fishing practices. MACBLUE, along with government partners, addresses these challenges by promoting sustainable management practices, conducting restoration projects, and engaging communities in conservation efforts. Local knowledge is integrated into the restoration process. In Papua New Guinea, for example, together with The Nature Conservancy, we support the government in drafting a Blue Carbon Policy that will provide the necessary tools for conservation.

Q: What are the different seagrass restoration techniques used in the Pacific, and what have been the results?

Linzatti: Restoration techniques include transplanting seagrass patches with their sediments (known as “sods and turf”) and sediment-free methods like the biodegradable mesh fabric method and the mesh wire frame method. Results have shown that the sods and turfs transplant method has been particularly effective in boosting survival rates and accelerating recovery in degraded meadows, with high community participation in restoration activities.

Q: How does MACBLUE locate and assess potential seagrass restoration sites in the Pacific countries where it operates?

Linzatti: MACBLUE uses satellite imagery, field surveys, and community input to identify and assess potential restoration sites. These methods ensure that the sites selected offer the best conditions for successful restoration and long-term sustainability. Community engagement is a key success factor!

Village of Nataleira supporting conservation work on seagrass.

Q: What was the timeframe for observing the restoration process? Which method was the most effective, and were there any that failed?

Linzatti: The restoration process typically spans several months to a year. The sods and turf method proved to be the most effective in terms of survival rates and planting efficiency, while other sediment-free methods were less successful in our pilot sites.

Q: Could you discuss the significance of the seagrass restoration project and its expected impact on the local community?

Linzatti: The pilot project with the coastal communities of Dawasamu – Driti, Silana, Nasinu, and Nataleira, implemented jointly with Fiji National University and the Fiji Locally Managed Marine Area Network, involved both restoration and community engagement. Local villagers, including youth groups, played a crucial role in monitoring and restoring seagrass meadows. The project aimed to improve the health of local ecosystems and support sustainable livelihoods. Coastal fisheries, a key source of nutrition and income for the community, depend on healthy seagrass meadows, as well as healthy mangrove and coral ecosystems. The Seagrass Pilot Project is one of the first of its kind in the Pacific, and we hope the lessons learned will be replicated in future restoration activities in the region.

Q: What lessons have been learned from seagrass restoration efforts?

Linzatti: Key lessons include the importance of collecting a controlled number of sods from healthy seagrass beds and conducting restoration activities during low tides for optimal planting. Physical markers and geotags should be used for site identification. Additionally, community involvement and integrating local knowledge have been critical to the success of restoration projects.

Q: What were the positive outcomes of seagrass restoration for coastal communities?

Linzatti: Local communities, especially youth groups, gained valuable skills in environmental stewardship, which will help ensure the sustainability of these ecosystems. In the long term, seagrass restoration should lead to improved marine biodiversity, increased fish populations, and better shoreline protection – though our project hasn’t run long enough to observe those changes yet.

Q: How does seagrass conservation contribute to food and income security for coastal populations in Pacific Island countries?

Linzatti: Conserving seagrass meadows helps maintain healthy fish populations, which directly support food security and income for coastal communities. Research shows that a 100m² patch of seagrass can support up to 8,000 tons of fish a year. By ensuring stable marine ecosystems, seagrass meadows provide a reliable source of protein, income from fisheries, and contribute to overall coastal resilience.

Q: How does MACBLUE plan to increase community awareness about the importance of healthy seagrass meadows?

Linzatti: MACBLUE plans to increase awareness through community workshops, educational materials, and engaging leaders and government partners in our partner countries. The project also aims to incorporate traditional knowledge into conservation efforts to build a deeper connection between communities and seagrass ecosystems.

Q: What future initiatives are planned under the MACBLUE project to further enhance seagrass conservation and management?

Linzatti: Future initiatives under MACBLUE include expanding seagrass restoration efforts across the region. We are planning a seagrass restoration initiative in Fiji’s Coral Coast, based on the lessons learned from the pilot project in Nataleira, to be launched soon. Additionally, as mentioned, we plan to implement local management projects in all four partner countries, together with coastal communities.

As the world celebrated World Seagrass Day, projects like MACBLUE are demonstrating that dedicated conservation efforts can make a difference. By integrating scientific research, policy advocacy, and community engagement, the future of seagrass ecosystems in the Pacific looks promising. Protecting these vital underwater meadows will not only ensure marine biodiversity but also support the livelihoods of coastal communities for generations to come.

This article was originally published on Pasifika Environews.