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UN Decade on Restoration : what is coral restoration & why is it useful?

UN Decade on Restoration : what is coral restoration & why is it useful?
Publié par Florina Jacob | Publié le 16 June 2021

The problem: coral ecosystems are at risk


Tropical coral reefs gather between one third and one quarter of known marine species. This diversity provides benefits for human communities around the world. Around 330 million people live within 30 km of coral reefs [1], receiving direct benefits like fisheries and tourism-related jobs, food resources, coastal protection and cultural value [2].

In parallel, the less known cold-water coral ecosystems are distributed around the world’s ocean and have an important role in nutrient cycles, as well as biodiversity support, including human communities (Cordes et al, 2016). They provide habitat for marine organisms, support fisheries and diving tourism for the most shallow ones [3].

However, coral ecosystems worldwide have faced rapid degradation since the 20th century [4]. Globally, coral reefs are one of the most affected marine ecosystems facing global warming, even in the most optimistic scenarios [5]. Ocean acidification, ocean warming, sea level rise and changes in storms and precipitation threaten coral communities by generating thermal stress, increasing sedimentation, and reducing pH levels, amongst other processes  [5,6]

At the local and regional scale, destructive fishing, pollution, coastal development and mineral extraction are common drivers that increase the vulnerability of coral bottoms to global pressures [4].

It has become clear that social and environmental systems are interconnected. Human activities have an effect (either positive or negative) on the structure and function of ecosystems, which at the same time result in a different supply of ecosystem services to humans [7,8].


What is coral restoration?


Coral restoration consists in assisting the recovery of the reef’s structure or functionality that has been degraded or destroyed, and that will impact the value and services provided by the ecosystem [9, 10]. This strategy has been increasingly recognized as a useful tool to counter ecosystem degradation and accelerate their recovery after strong impacts [9]. 

However, coral restoration is not a one size fit all solution. 

If the main pressures of coral reefs occur on a local or regional scale, coral restoration can be part of a management strategy addressed to strengthen the resilience of the ecosystem, but it isn’t a solution on its own [12].

Currently, the goal of coral restoration is not to return to a historical baseline of ecosystem condition, but to contribute to the recovery of some key processes and services [9]. In fact, the elimination in the short term of some global threats is virtually impossible, considering that ocean temperatures and pH will take decades to stabilize [11]. 

The social dimension of a restoration or conservation strategy is equally important. The support of local actors can be decisive for achieving ecosystem recovery in the long term. The involvement of local communities in the different stages of the project is a way to empower them in the ecosystem stewardship, and hence contribute to the projects’ sustainability [13].


Where and how is coral restoration occuring?


According to the review published in 2020 by Lisa Bostrom-Einarsson and collaborators, coral restoration in tropical reefs is currently developed in at least 56 countries around the world, 40% of which occur in the USA, Philippines, Indonesia and Thailand (Fig. 1). 

50% of the reported projects report a short duration (median of 12 months), and cover on average 100m2, showing a trend for short term and small-scale projects. The main technique is the transplantation of coral fragments (40% of all projects) using epoxy putty to attach corals to the substrate (30% of all projects) (click here for more results of this study [14]).



Distribution of coral restoration projects around the world

Fig. 1. Distribution of coral restoration projects around the world. Data points are coloured by country. Source: [14]


Regarding ecological restoration on cold-water coral ecosystems, the efforts are much more limited. Why? Some of the reasons concern the technical difficulties in accessing the areas, related high-costs and the limited knowledge on these ecosystems [3]. However, amongst existing initiatives, in the Mediterranean for example, the gorgonian coral transplantation on artificial structures has provided valuable information about restoration techniques in this environment (you can learn more via the Merces project). 


What is the UN Decade on Ecological Restoration?


This year, the UN has launched the UN Decade on Ecological Restoration from 2021 to 2031 as a call for governments, enterprises, NGOs, scientists and all citizens to take action for ecosystem recovery across the world. This decade seeks to advance in the achievement of the Sustainable Development Goals linked to biodiversity conservation, improving livelihoods, ensuring food security and combating climate change, through ecosystem restoration. You can find out more about the decade here.

At Coral Guardian we see coral restoration as a means to involve local communities in coral conservation and raise awareness on the importance of corals.

Currently, we accompany three projects around the world in very different contexts, through our Blue Center programme. The pilot project occurs in the heart of the Coral Triangle in Indonesia, around Hatamin Island, and aims to restore tropical corals from blast fishing hand in hand with the local community. The second project takes place along the Mediterranean coasts of Spain, in La Herradura where we accompany the NGO Equilibrio Marino in cold-water coral repopulation and seabottom recovery for the SOS Corales project. Finally, the third project occurs on the island of Martinique where we give advice to two local NGOs, Roots of the Sea and Guardians of the Earth, in the conception of their coral restoration project that aims to protect coral ecosystems by involving local actors.


You can be part of the solution too:

  • Reduce your carbon footprint: choose to cycle or public transport over a car. 
  • Reduce your fish consumption, and choose small scale and artisanal fisheries when buying fish, if possible.
  • Reduce your plastic consumption in your everyday groceries.
  • When visiting coral reefs, choose tourism initiatives that reduce their negative impacts on ecosystems and support local communities.
  • Help raise awareness and stay informed on initiatives around coral reefs in your area and worldwide!


You can also support our coral restoration projects directly by adopting a coral or donating monthly.


For more information: 


[1] World Resources Institute (2020) Coral reefs, status and outlook of coral reefs around the world. Online resource:


[2] Woodhead, A. J., Hicks, C. C., Norström, A. V., Williams, G. J., & Graham, N. A. (2019). Coral reef ecosystem services in the Anthropocene. Functional Ecology, 33(6), 1023-1034.


[3] Ros, Z.D., Dell’Anno, A., Morato, T., Sweetman, A., Carreiro-Silva, M., Smith, C.J., Papadopoulou, N., Corinaldesi, C., Bianchelli, S., Gambi, C., Cimino, R., Snelgrove, P., Dover, C.V., & Danovaro, R. (2019). The deep sea: The new frontier for ecological restoration. Marine Policy, 108, 103642.


[4] Burke L., Reytar K., Spalding M., Perry A. (2011) Reefs at Risk Revisited. World Resources Institute, Washington, D.C., DOI: 10.1016/0022-0981(79)90136-9


[5] Bindoff, N.L., W.W.L. Cheung, J.G. Kairo, J. ArĂ­stegui, V.A. Guinder, R. Hallberg, N. Hilmi, N. Jiao, M.S. Karim, L. Levin, S. O’Donoghue, S.R. Purca Cuicapusa, B. Rinkevich, T. Suga, A. Tagliabue, and P. Williamson, (2019) Changing Ocean, Marine Ecosystems, and Dependent Communities. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. Online resource:


[6] NOAA (2021) How does climate change affect coral reefs? Online resource:


[7] Berkes, F., and Folke C. (1998) Linking Social and Ecological Systems for resilience and sustainability. In book “Linking Social and Ecological Systems: Management Practices and Social Mechanisms for Building Resilience”. Cambridge University Press, New York.


[8] Chapin, F., Kofinas, G., & Folke, C. (2009). Principles of ecosystem stewardship : resilience-based natural resource management in a changing world.


[9] Hein, M.Y., Beeden, R., Birtles, R.A., Chase, T.J., Couture, F., Haskin, E., Marshall, N., Ripple, K., Terry, L., Willis, B.L., Willis, R. and Gardiner, N.M. (2020) Effects of coral restoration on fish communities: snapshots of long-term, multiregional responses and implications for practice. Restor Ecol, 28: 1158-1171.


[10] Edwards, A.J. (ed.) (2010). Reef Rehabilitation Manual. Coral Reef Targeted Research & Capacity Building for Management Program: St Lucia, Australia. ii + 166 pp.


[11] IPCC, 2018: Global warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [V. Masson-Delmotte, P. Zhai, H. O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J. B. R. Matthews, Y. Chen, X. Zhou, M. I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, T. Waterfield (eds.)]. In Press.


[12] McIeod, E., Anthony, K., Mumby, P. J., Maynard, J., Beeden, R., Graham, N. et al. (2019). The Future of Resilience-Based Management in Coral Reef Ecosystems. Journal of Environmental Management 233, 291-301.


[13] DeAngelis, B.M., Sutton-Grier, A.R., Colden, A., Arkema, K.K., Bailie, C.J., Bennett, R.O. et al. (2020). Social factors key to landscape-scale coastal restoration: Lessons learned from three US case studies. Sustainability 12, 869. doi:10.3390/su12030869 


[14] Boström-Einarsson L, Babcock RC, Bayraktarov E, Ceccarelli D, Cook N, Ferse SCA, et al. (2020) Coral restoration – A systematic review of current methods, successes, failures and future directions. PLoS ONE 15(1): e0226631. 

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