Studies reveal massive mangrove damage in Great Barrier Reef and restoration hotspots

A James Cook University report revealed severe damage to around 80% of mangroves in the Great Barrier Reef from Cairns to Gladstone – and identified 52 potential restoration hotspots over 17,255 hectares.

The findings bring hope and urgency to World Mangrove Day, providing a path to recovery and highlighting the critical need for conservation.

The Great Barrier Reef Mangrove and Saltmarsh Status Review The report used 80,000 high-resolution geo-referenced photographs from helicopter surveys to reveal the profound impacts of sea-level rise, hurricane damage and pollution on mangrove habitats.

JCU TropWATER researcher Professor Norm Duke said mangroves along the coast of the Great Barrier Reef had never been studied to this extent before, and the results showed huge damage.

„Our observations provide clear, unambiguous and quantifiable evidence of changes in this increasingly dynamic coastline,” he said.

„You can see how sea level is rising along the mangrove coast, where the mangroves are simply collapsing at the sea’s edge.

„The impact of severe tropical cyclones over the past four decades has hit the region, notably Yasi in 2011 and Tebi in 2017. We can also see extensive loss of coastal trees and erosion of salt pans and retreat of terrestrial shorelines. .

„This is widespread evidence of sea-level rise.”

Professor Duke said the aerial observations were consistent with local records of sea-level rise over the past half century, indicating an increase of at least 4mm per year.

Mangroves are nature’s blue carbon powerhouses—capable of sequestering and storing significant amounts of carbon, making them an important tool in mitigating the climate crisis. They are also biodiversity hubs, providing essential breeding grounds for native fish, while stabilizing coastal ecosystems and reducing erosion.

The team has also identified 17,255 hectares of coastal land for reclamation at 52 potential sites. The findings provide insight into the opportunities and challenges for localized recovery and carbon sequestration, financed by carbon markets. This is an important step in preparing for coastal retreat and moving mangroves landward as sea levels rise.

Dr. of TropWATER. Adam Canning says maintaining the health of existing mangroves along the Great Barrier Reef is critical, identifying potential restoration sites is an essential step in the climate crisis to sequester carbon and manage coastal retreat.

„Until now, beyond very limited desktop exercises, no one knew where the lost forests in the Great Barrier Reef could be restored and what their potential for carbon sequestration would be,” he said.

„We used a combination of complementary methods to identify the best sites for restoration, their potential for carbon storage, and the specific restoration challenges one might face.

„We have combined our field studies with detailed digital elevation models, 3D imagery of the landscape, tidal intrusion mapping, long-term satellite monitoring of mangrove health, land ownership and regulatory triggers.

„We also identified potential risks for each potential project and key factors that would cause change, such as pollution, access tracks, feral pigs, sediment deposition, shoreline erosion and storm damage.

Greening Australia is already using the report’s findings to assess the feasibility of blue carbon ecosystem restoration for two projects in the Mulgrave and Mackay regions.

Greening Australia’s Reef Aid Director, Dr. Lynise Wearn said the research contributes important data to the field of blue carbon restoration and highlights the need and urgency to increase investment in coastal restoration activities.

„The report highlights the challenges of restoring blue carbon ecosystems, but there is also research showing that these systems can respond quickly to interventions such as active vegetation and tidal flooding and achieve carbon storage.

„These coastal ecosystems are critical to climate resilience and biodiversity, as well as having deep cultural significance to First Nations communities. Greening Australia is committed to driving investment and working with First Nations communities to restore threatened coastal ecosystems.”