Research

The challenge

Coastlines are under a variety of pressures. Sea level rise is squeezing coastal defences and land-use practices have cleared 1000’s of hectares of mangroves; nature’s primary defence. In urban locations, marinas and port expansions have replaced mangroves with concrete or rock walls.

In coastal communities, the impacts have been severe:

Environmental

Mangrove loss has lead to increased flooding and coastal erosion risk. Declining mangrove and saltmarsh habitat also results in reduced carbon sequestration, declines in marine and estuarine water quality, reduced biodiversity, and decreases in sustainable fishing yields. Impacts on the health and biodiversity of adjacent seagrass and coral reef ecosystems are also of grave concern.

Economic

Coastal farmers face increasing pressures due to the degradation of lands and declining crop yields. Decreasing profitability can lead to reduced climate resilience and wellbeing for farmers and coastal communities. Degraded coastal environments also negatively impact fisheries, coastal protection, and tourism and the livelihoods they support.

Social/Cultural

Reduced income and environmental integrity has a direct impact on health, wellbeing, and educational outcomes. Mangrove ecosystem loss also impacts fishing and recreation activities, increases flooding risk, and limits the harvesting of mangroves for wood, fuel products, and traditional foods and medicines.

The solution

Researchers from UNSW Sydney and the University of the South Pacific (USP) will transfer two emerging nature-based solutions developed at UNSW and pilot them in Fiji. In partnership with local communities the Project Halo team will seek to systematically re-instate natural tidal flows to revitalise the local mangrove ecosystems for the benefit of people and the environment. The project team will also examine how mangrove ecosystems could be repurposed within marinas and urban areas to harness the benefits of nature within concrete landscapes.

Tidal restoration of blue carbon ecosystems

Sea walls and tidal gates restrict tidal cycles, cutting off mangrove seascapes. However, existing approaches to restore mangroves has typically resulted in high failure rates. Novel lifecycle-based solutions, developed at UNSW Sydney, offer alternative options to maximise co-benefits and increase on-ground success rates. These approaches:

• support the regrowth of blue carbon ecosystems, including mangrove forests
• drive enhanced environmental, economic and social outcomes.

Floating mangrove infrastructure: a halo-phyte revolution

Imagine a mangrove forest. Now, imagine that same habitat providing sustainable ecosystem services in urban and marine areas. Based on techniques developed in partnership with UNESCO, UNSW Sydney, and USP Fiji researchers are designing novel floating mangrove technologies with the aim of:

• improving water quality and absorbing wave energy,
• adding nature-based solutions into maritime structures,
• reducing deforestation pressures on existing mangrove habitats,
• increasing coastal blue carbon sequestration, and
• providing habitat in highly urbanised “biodiversity deserts”, and
• greenifying an increasingly urbanised world.

This work will underpin the natural power of mangrove ecosystems and help rejuvenate coastal spaces that support tourism and other industries

The benefits

Over five years, researchers will track the environmental, social, and economic outcomes of Project Halo in Fiji.

Expected benefits include:

Environmental

• Increases in healthy mangrove habitats
• Improved marine and estuarine water quality
• Increased biodiversity levels
• Enhanced carbon sequestration
• Improved shoreline protection

Social

• Incorporation of traditional knowledge and values into newnature-based solutions
• Community willingness to support climate change adaptation activities
• Potential for diversified household income and wellbeing resulting from blue carbon farming
• Improved progress towards the United Nations Sustainable Development Goals

Economic

• Increased family/community incomes
• Willingness to uptake nature-based economic solutions
• Attraction of research opportunities in the future
• Growth in local tourism opportunities

Charting a path towards the SDGs

Project Halo is designed to support the UN’s 2030 Sustainable Development Goals and the 2021-2030 Decade of Ecosystem Restoration. As well as building international environmental science and engineering workforce capacity, this research ensures Fiji is a global leader in piloting innovative and ambitious approaches to address climate change and meet 2050 carbon targets. It offers significant potential for other countries in the South Pacific and for the Blue Pacific Continent.