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CORAL REEF REHABILITATION AND RESTORATION

Coral reef rehabilitation and restoration efforts are designed to support the resilience of degraded reef environments. While some restoration projects in the Pacific have focused on reducing stressors, like removing invasive species and reducing runoff, there are now many innovative approaches to restoring coral reefs, which include planting nursery-grown coral, relocating tolerant species of coral into degraded areas and seeding new reefs in areas that are, or will become, more suitable for coral reef species. 

Image removed.While improvement in techniques and monitoring of restoration success is being driven through significant donor  investment, there remains a need for strategic restoration plans to guide investment for coral restoration projects.

Importantly, associated habitats and systems can also benefit from link restoration activities. For example, seagrass restoration projects can increase connectivity between marine ecosystems and critical habitats for recruitment and  growth of many species.  

Methods of restoration     

 

Coral nurseries            

Image removed.Harvesting wild corals for growth in nurseries is a popular approach for restoration of degraded coral reefs. The  approach typically involves sub-lethal harvesting of robust or target species. The fragments are grown in nursery areas prior to their re-deployment on target reefs.

 

 

 


 

Coral relocation

Image removed.

Coral relocation has been used to offset development impacts for decades. The method involves moving corals from vulnerable areas and relocating them to pre-determined relocation sites. Historically, these relocations have focused on moving corals from areas of development, but there is now renewed focus on the value of relocating corals as an adaptation strategy. In these instances, corals can be moved from healthy reefs and transplanted into reef areas that have been degraded. Some of the most well studied coral relocation projects have been undertaken in Hawaii, where strong recruitment success has been reported. 

 

Coral seeding

Image removed.Techniques to harness coral diversity through spawning in natural and artificial settings have begun to attract more  research and application focus in recent years, with efforts designed to maximise the diversity of coral reefs and  build their resilience to change. While these techniques have recently been established and applied on the Great Barrier Reef in Australia, there remains work to be done, on both the research and application fronts to ensure that this approach can be applied widely throughout the Pacific.

 

  • Can support reef recovery, especially after extreme bleaching events or cyclone damage.
  • Can be very focused, either spatially (on a specific reef) or on species in need of restoration.
  • Global networks have established methods and support to enable reef restoration works to succeed.
  • Healthy coral reefs support coastal communities and buffer wave action, reducing risks of coastal erosion.
  • Healthy coral reefs support coastal communities through the provision of food.
  • Healthy coral reefs support coastal communities wishing to develop tourism.
  • Restoration doesn’t address underlying causes of degradation, so conditions may still lead to impacts.
  • Reef nursery approaches are resource intensive and take time to achieve goals.
  • Reef nursery methods favor a small subset of coral types.
  • Restoration approaches don’t always consider connections between adjacent ecosystems.
  • Restoration is not well linked to ecosystem service support and delivery.
Indicative cost

Coral reef rehabilitation and restoration is medium cost as no major infrastructure works are required. Costs can be offset by engaging local people and tourists in the work. Whilst providing cost estimates is difficult given the broad range of influencing factors across the Pacific, the below table outlines the key components that should be taken into account when estimating an coral reef rehabilitation project budget for a specific location.

Components

Unit
(A)

Number of units (B)

Unit Cost
(C)

Budget
(B x C)

Establishment Cost

        
  • Planning and design including community outreach

e.g hours

      
  • Site selection and preparation 

e.g. hours

      
  • Materials (e.g. wild corals, nursery materials)

e.g. number

      
  • Labour (specialist labour required)

e.g. hours

      
  • Reporting to donor (if required)

e.g. hours

      

Ongoing Cost

        
  • Maintenance Cost (materials and labour)

e.g. number and hours

      
  • Reporting and Monitoring

e.g. hours

      

The restoration and rehabilitation of coral reefs represents an ecosystem-focused adaptation that supports diverse and dynamic marine environments which deliver multiple benefits for local communities. In contrast, degraded reefs offer reduced supporting and provisional ecosystem services. These functions can only partially be delivered through engineering approaches (such as the installation of sea walls to reduce coastal erosion risk) and many engineering approaches can create additional climate hazards and threats to community stability.

On-ground impacts that the EbA option addresses
Coral bleaching
Reduction of types of species
Loss of seagrass
Calcification of coral

Case study

Restoring Coral Gardens – Mission Blue

Fiji

Efforts to support reef recovery from climatic and non-climatic threats have generated opportunities for community-led restoration efforts along Fiji’s coral coast. The Mission Blue project restoring coral gardens, engages youth and village elders to support sustainable coral reef management through education and training.

The approach uses broken or selected pieces from donor corals, which are secured to large racks and grown for between 6 to 12 months. Once the fragments have increased in size and health, they are then re-planted onto affected reefs to build structure and ecosystem complexity and maintain coral diversity.

Over 1,200 corals have been established across five sites and an additional 7,500 new coral colonies are currently being propagated in nurseries by local village groups. Importantly, this work has not just focused on a single species, with more than 30 species across 12 coral genera being cultivated to date.

Reference: Restoring Coral Gardens in Fiji,  https://mission-blue.org/2015/12/restoring-coral-gardens-in-fiji/