Author: Skylar Collins
Editor: Jill Ashey
It is well-known that the Great Barrier Reef (GBR) is under threat, but could the tourism industry provide a flicker of hope for this landmark ecosystem? The GBR stretches for 2,300 km off the northeast coast of Australia, making it the largest coral reef system in the world. Not only is it of immense ecological importance but it also has great social, cultural, and economic value. In recent years, climate-induced mass coral bleaching events have led to large-scale declines in coral cover across the GBR. This is bad news for the vast number of organisms that rely both directly and indirectly on the reef, but also for the many Australian citizens who depend on it for their livelihoods, such as tourism operators.
What is being done to combat the decline of the GBR? Addressing the cause of decline through global climate change mitigation may be the obvious answer (and the answer we hope for), but without international political change, this is no simple task. Instead, scientists and reef restoration practitioners are taking matters into their own hands. Through coral reef restoration initiatives, groups across the globe are actively restoring degraded reefs. Recent decades have seen huge growth and development in the various methods of coral reef restoration, but coral transplantation remains the most popular. This involves the direct attachment (also known as ‘out-planting’) of naturally occurring or nursery-grown coral fragments onto the reef substrate, with the goal being to rebuild degraded coral communities over time.
Coral nursery (left). Coral fragments being transplanted by a CNP member (right) on the GBR. (Coral Nurture Program, https://www.coralnurtureprogram.org/more-info/photo-gallery)
However, coral reef restoration is extremely costly and time-consuming, and the short-term nature of most reef restoration efforts (< 1.5 years) combined with the slow-growing nature of corals makes any substantial increase in coral cover difficult to achieve on a large scale. To combat these restraints, the ‘Coral Nurture Program’(CNP), a partnership between scientists and tourism operators on the GBR, developed a physical attachment device – the Coralclip®. This low-cost, fast deployment technique was created to integrate reef restoration as a site stewardship practice in specific areas within the GBR.
Coralclip® device (left) and Coralclip® being used to attached a coral fragment to the reef (right). (Suggett et al., 2020).
A recently published study from CNP scientists using the Coralclip® found that coral transplantation by tourism operators over the previous two years on the GBR had variable effects between the six study areas.
Six study sites for coral transplantation on the Great Barrier Reef (Howlett et al., 2023).
One study site, Upolu Reef, found significant increases in hard coral cover almost 2.5 times higher in the out-planting sites versus the control site. Upolu initially had the lowest hard coral cover, so natural recovery rates were likely to be low. Given these low recovery rates, it may not be surprising that out-planting activities had the greatest effect here. Two other sites, More Reef and Opal Reef did see increases in hard coral cover but not to a significant extent. Increases were not observed at the remaining three reefs. The findings suggest that through this method, increasing out-planting intensity can–but not always–increase hard coral cover in out-planting sites over two years. The outcomes may depend on the initial state of the reef, and the success of this method of coral restoration may be improved by focusing on sites where natural coral cover is especially low. The potential for tourism operators to aid the restoration of reefs at specific sites, particularly where natural recovery is low, has been demonstrated, and further research in this area may look to measure other important elements of restoration ‘success’, including both ecological and socio-economic outcomes.
Boström-Einarsson, L. et al. (2020) ‘Coral restoration – A systematic review of current methods, successes, failures and future directions’, PLOS ONE. Edited by C.N. Bianchi, 15(1), p. e0226631. Available at: https://doi.org/10.1371/journal.pone.0226631.
Hein, M.Y. et al. (2021) ‘Perspectives on the Use of Coral Reef Restoration as a Strategy to Support and Improve Reef Ecosystem Services’, Frontiers in Marine Science, 8. Available at: https://www.frontiersin.org/articles/10.3389/fmars.2021.618303 (Accessed: 13 February 2023).
Howlett, L. et al. (2023) ‘Active coral propagation outcomes on coral communities at high-value Great Barrier Reef tourism sites’, Biological Conservation, 279, p. 109930. Available at: https://doi.org/10.1016/j.biocon.2023.109930.
Suggett, D.J. et al. (2020) ‘Coralclip®: a low-cost solution for rapid and targeted out-planting of coral at scale’, Restoration Ecology, 28(2), pp. 289–296. Available at: https://doi.org/10.1111/rec.13070.
Featured image: (Coral Nurture Program, https://www.coralnurtureprogram.org/more-info/photo-gallery)