Coral reefs all over the world are suffering the effects of climate change. Coral restoration has become a popular conservation strategy to replenish coral coverage lost to bleaching, disease, and other factors. Restoration efforts could maintain genetic diversity and improve coral reef resilience, but how effective are these programs?

Studies on the success of such programs have found high costs and low long-term success. A paper recently published in PLOS ONE found that survivorship of outplanted colonies of staghorn corals in the Florida Keys was initially high but decreased after two years, when growth rates plateaued. After seven years, at least 90% of the planted corals had died. 

Overall, these outplanting efforts preserve genetic diversity in the wild and keep extinction of endangered species in check, but significant human intervention will still be required until external stressors are reduced. Outplanting requires huge amounts of proactive human effort, and provides only temporary relief to the suite of problems facing corals, namely, climate change and the associated issues of warming temperatures, acidification, and disease. The results show that these stressors are the problems we should be targeting if we want to save coral reefs.