Dozens of coral reefs have been restored in Indonesia in just four years

In the Palau Bontosua area, in the southwestern portion of the Indonesian island of Sulawesi, all the degraded coral reefs have been restored in just four years.Due to global warming and human activities, the coral reefs in the area had been virtually destroyed.But now, thanks to a specific restoration program, they are growing at the same rate as healthy ones.To allow the corals to reform, barriers have been installed hexagonal steel structures covered with sand, which stabilizes debris and provides a habitat for reef fauna.However, although this is an excellent result, the researchers warn that the technique used represents a last resort which should not be used systematically.The barriers thus restored present in fact a lower species diversity compared to healthy ones.

A team of Indonesian and British scientists worked on the project as part of the Mars Coral Restoration Program, a large-scale effort to restore the coral reefs destroyed by fishermen who used explosives to kill and capture fish 30-40 years ago.Specifically, the researchers positioned the “Reef Stars”, hexagonal structures made locally in steel and covered in sand, placing them in strategic points of the seabed once without vegetation.A network of these metal structures was used to stabilize dead and floating coral debris, residues of barrage fishing, and live corals have been transplanted onto these steel skeletons, which therefore have a solid support point to grow and are not at risk of being damaged.Fast-growing branching corals, as well as logistical ones, offer the more immediate benefits in terms of coral cover, structural complexity and carbonate production.On the other hand, however, restored coral reefs may be less diverse in terms of biodiversity and habitat than natural ones, which are home to more massive corals and large-scale structures.Scientists hypothesize that, over time, the sites will recover they will succeed to recover the structure and functions of nearby undisturbed coral reefs through natural ecological processes, such as coral growth and recruitment, but a big question mark concerns the timing aspect.

As has happened several times in recent years explained by scientists involved in the monitoring and restoration project Mars Coral Reef Restoration Program, once the coral reef comes back to life their chances of becoming self-sufficient increase also and above all thanks to the animals that settle there, which in turn attract others of their kind, creating an increasingly diversified environment.The possibility of recovering entire coral reefs is undoubtedly a very important fact, especially if we consider that, in Indonesia, more than a third of these they are in very poor condition.However, there are many threats looming over these ecosystems, which must not be forgotten.In fact, scholars specify that, if climate change and water pollution persist and worsen, environmental conditions will become increasingly hostile to their rescue.

[by Stefano Baudino]