Coral Restoration: Active vs Passive

There are two types of restoration efforts when it comes to coral reefs: passive and active. Passive approach focuses on minimising the negative impacts that cause reef degradation and hoping that the ecosystem will recover by itself. This method consists of management plans to improve the environment, for instance the establishment of marine protected area (MPA), or formulation of laws that can protect marine habitat. However, depending on the condition of the coral reefs there is a chance that this is not an effective method. The magnitude of the degradation may be too high for us to just depend on natural process.  

This brings us to active restoration approach. This technique involves direct actions to the coral reefs to speed up recovery process that can increase coral reefs health, abundance, or biodiversity. Some of the examples are direct transplantation, coral gardening, and artificial reef. Active method is often used to reduce the decline of coral reefs and help speed up the recovery. Nevertheless, it is important to involve both active and passive strategies. The most effective outcome should include both habitat protection and restoration to increase natural recruitment and help the ecosystem to have functional structure. 

The Biorock technology (also known as mineral accretion technology) is an example of an active approach. Developed by Professor Wolf Hillbertz and Dr. Tom Goreau, this technology involves having low-voltage currents to a marine structure (of any shape and size) that will then form calcium carbonate around the structure due to the electrolysis process. What is special about the Biorock structure compared to other methods is that the structure will get stronger and more effective as it ages, has the ability to self-repair, and more importantly, it provides a lot of benefits for humans and marine animals.

For instance, the Biorock structure can act as a breakwater for shore protection. In addition to that, it has shown that the structure increases the settlement, growth, survival of corals and helps them with stresses such as high temperature and sedimentation. Moreover, corals grow faster and have higher chance of survival in the Biorock structure. Other organisms such as fishes may also increase in population thanks to Biorock. The structure is an ideal place to replace destroyed habitats, allowing fishes to hide from predators and provide nursery grounds. 

To conclude, there are two ways of coral reefs restoration: active and passive. In passive approach we try to minimize the cause of reef degradation without direct intervention, for example the creation of an MPA or laws. Meanwhile, active approach engages in direct involvement. For conservation measures to be effective, both methods should be applied hand in hand. The Biorock technology is one example of an active method. It is a special technology that is useful for both humans and the environment for shore protection and conservation of the marine life.

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References:

Edwards, A. J., & Gomez, E. D. (2007). Reef Restoration Concepts and Guidelines: Making sensible management choices in the face of uncertainty.

Goreau, T. (2014). Electrical Stimulation Greatly Increases Settlement, Growth, Survival, and Stress Resistance of Marine Organisms. Natural Resources, 05(10), 527–537. https://doi.org/10.4236/nr.2014.510048

Goreau, T., & Hilbertz, W. (2005). Marine ecosystem restoration: costs and benefits for coral reefs. World Resource Review, 17(3), 375–409.

Hein, M. Y., Beeden, R., Birtles, A., Gardiner, N. M., Le Berre, T., Levy, J., Marshall, N., Scott, C. M., Terry, L., & Willis, B. L. (2020). Coral restoration effectiveness: Multiregional snapshots of the long-term responses of coral assemblages to restoration. Diversity, 12(4), 1–22. https://doi.org/10.3390/D12040153

Possingham, H. P., Bode, M., & Klein, C. J. (2015). Optimal Conservation Outcomes Require Both Restoration and Protection. PLoS Biology, 13(1), 1–15. https://doi.org/10.1371/journal.pbio.1002052

Rinkevich, B. (2008). Management of coral reefs: We have gone wrong when neglecting active reef restoration. Marine Pollution Bulletin, 56(11), 1821–1824. https://doi.org/10.1016/j.marpolbul.2008.08.014