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Description
These models (Transects 1 and 2) represent two portions of the coral reef that surrounds Bileiydhoo, one of the five inhabited islands of the Faafu Atoll. This island is located in the central part of the Atoll lagoon.
In 2016, the reefs of the Republic of Maldives were affected by a bleaching event, followed by coral mass mortality. During the bleaching, the most affected corals were tabular and branching Acropora spp, the primary habitat-forming species in the shallow reef environment of the Maldives. Mortality rates in this genus reached 80%; signs in colonies desegregation were already recorded a few months after the event, which completely changed the structure of the reefs of the archipelago; the following recovery process has been uneven and prolonged.
Some reefs showed a grater resilience than others, and the Beleiydhoo reef is one of these. The coral reef surrounding the island of Bileiydhoo is in full recovery. Four years after the bleaching event, the coral coverage is increasing, and Acropora is again the dominant genus on this part of the reef. Along the transect, it is possible to notice the abundance of tabular growth forms, all with more or less the same diameter. This means that, after the mass mortality of 2016, the space left free on the substrate was recolonized by the larvae of Acropora spp. The new colonies were able to grow smoothly, thanks to the low level of competition and the lack of direct anthropogenic impacts on that side of the island.
However, the recovery is not uniform throughout the atoll. Most of the coral reefs are struggling to recover after the catastrophic bleaching events, as the recovery process can be negatively impacted by the increase in coral reefs exploitation from fisheries activities, tourism and land reclamation. Moreover, the action of corallivorous organisms on small coral colonies and recruits can further prolong the recovery time.

Credits: model provided by Luca Fallati, MaRHE Center (https://marhe.unimib.it/)

References

  • Marine Research Center. (2016). Status of Coral Bleaching in the Maldives
  • Perry, C. T., & Morgan, K. M. (2017). Bleaching drives collapse in reef carbonate budgets and reef growth potential on southern Maldives reefs. Nature Publishing Group, 7(November 2016), 1–9.
  • Pisapia, C., Burn, D., & Pratchett, M. S. (2019). Changes in the population and community structure of corals during recent disturbances (February 2016-October 2017) on Maldivian coral reefs. Scientific Reports, 9(1), 8402.
  • Sully, S., Burkepile, D. E., Donovan, M. K., Hodgson, G., & van Woesik, R. (2019). A global analysis of coral bleaching over the past two decades. Nature Communications, 10(1).