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UN Decade on Restoration

Coral restoration in a warming world

Coral restoration is emerging land management, have led to major by a further 70–90% with a 1.5°C as a strategy to combat the improvements in some areas. Despite increase in global mean . coral reef crisis, but, in an era of these actions, many valuable marine Recent bushfires, flooding, and coral warming , is it a worthwhile continue to decline and bleaching are clear signs that climate endeavour? By Ian McLeod and active restoration is increasingly change is impacting at scale. With Maxine Newlands. being seen as an economically viable climate models predicting that even management option. Usually, active he United Nations Decade of restoration can only be successful Ecosystem Restoration once the drivers of decline have been Box 1. What is coral T (2021–2030) is a clear sign reduced or eradicated. For example, restoration? that restoration is becoming a major hundreds of hectares of oyster reefs are The earliest coral restoration projects priority on land; yet being rebuilt in Chesapeake , US, involved direct transplantation of coral restoration is contentious. Whilst because they could not recover on their colonies, often away from areas of land-based ecosystem restoration own after destructive ended. development such as pipelines. In the is well established, the science to Coral reefs are some of the most 1980s, coral gardening projects where restore our oceans’ health at scale is threatened ecosystems on the planet. coral fragments were grown in an less developed. Critics claim marine They support the livelihoods of at intermediate nursery phase began. This ecosystem restoration is expensive, least 500 million people through allowed for a multiplication of fragments has a high risk of failure, and activities such as fisheries and , as could be grown and frag- mented many times before outplanting. distracts the conversation away from and are worth an estimated US$375 More recently, new methods to tackling global . billion per . Reductions in coral encourage coral recovery have been Until recent decades, marine reef health have been recorded in all trialled. In , teams of divers have management has focussed on passive major tropical oceans since the 1980s, been removing over-growing, invasive restoration by reducing stressors that with an average of 30–50 per cent with the help of an underwater caused the damage. Actions such as reduction in coral cover globally. vacuum. In the , coral managing destructive Global climate change is the key has been captured and reared until ready to settle, with millions of larval through marine protected areas, or driver of coral reef decline from corals then added to degraded reefs. In coastal through improved associated bleaching events, disease , the pet food and confection- Figure 1. (main picture) Coral research in the outbreaks, and from ary company Mars, Incorporated has Australian Institute of Marine Science’s warming . The Intergovernmen- developed ‘reef stars’; frames that are Simulator. Image © Australian Institute of tal Panel on Climate Change forecasted linked together and seeded with corals Marine Science / Christian Miller. the world’s coral reefs would decline to consolidate areas of coral rubble.

26 The Marine | April 2020 UN Decade on Ecosystem Restoration if we stop all emissions of greenhouse In the US, the National Oceanic Alongside these government-led gases today, warming will continue and Atmospheric Administration initiatives, the Coral Restoration for decades, then why invest in coral (NOAA) and partners have developed Consortium (CRC) is a rapidly restoration (see Box 1) if the stressor, an unprecedented, decades-long growing network of coral restoration climate change, has not been removed? approach to restore seven iconic groups. The CRC is a 6,000-strong Recently, an international team of reef sites in Keys National community of practice comprising scientists looked at 362 cases of active Marine Sanctuary. The project, Reef scientists, managers, coral restoration coral restoration methods from 56 Icons, involves removing nuisance practitioners, and educators with countries across four decades. Their and invasive , like seaweed and a focus on knowledge sharing and study showed that over 200 different coral predators, before a rebuilding collaboration. A new report from the species of corals have been used and programme that includes planting United Nations and the International survival of restored corals was relatively clusters of a range of coral species, Coral Reef Initiative (ICRI) found that high, between 60 and 70 per cent, followed by the addition of urchins and nine ICRI member countries currently demonstrating that it is possible to to keep seaweed under control. have or are developing best practice successfully grow corals at smaller scales. The research team also identified common issues in projects including a lack of clear and achievable objectives, or appropriate, standardized monitor- ing and reporting, along with many projects that were poorly designed in relation to their stated objectives. Despite some of the recurring challenges in coral restoration projects, some nations are investing in coral restoration in a major way. In , the federal government—through the Reef Trust Partnership—has invested close to AU$100 million into the Reef Restoration and Adaptation Program, seeking to scale-up and accelerate reef restoration and adaptation science to help protect the (Figs. 1 & 2). The initial scoping and design phase has been completed and seven categories of interventions have been identified for the next five of research and development (Box 2). These interventions include ways to protect corals by reducing their exposure to extreme temperature stress by making environmental adjustments that, for example, increase shade or cool the . It could also include assisting coral populations to more rapidly build natural resilience to threats such as higher , through measures such as selective breeding or genetic engineering. Other interventions aim to accelerate natural recovery, for example, modifying reef surfaces to promote growth (Fig. Figure 2. Larvae are settled onto 3D printed shapes in the laboratory, and the shapes are then 3), and producing and distributing wedged into areas of the reef lacking live coral. Deployment shown here on the Great Barrier coral larvae on a large scale (Fig. 4). Reef. © Australian Institute of Marine Science / Andrea Severati SECORE.

April 2020 | The Marine Biologist 27 UN Decade on Ecosystem Restoration

Figure 3. using structures: three-year time series of coral growth on coral tables in Pulau Hatamin, Indonesia. Photo by Martin Colognoli for Coral Guardian. and policy guidelines for coral restora- mates that if reefs continue to decline, and restoration will be necessary. tion projects. The average annual spend their annual value could fall by US$3.1 Where next for coral restoration? of ICRI members on coral restoration billion in Mesoamerica and US$2.2 This year and the next will be ranged between US$30,000 to US$1 billion in the by 2030, significant for coral reef conserva- million. These numbers are dwarfed by adding that measures to address this tion and restoration. In the political the amount that could be lost if reefs decline, from large and cost-effective sphere, the implementation of the continue to degrade. A UN report esti- investments in coral reef conservation Paris Accord is hoped to reduce global carbon emissions whilst Australia and the US lead the way in reef restora- Box 2. Types of interventions being investigated through the Reef Restoration and Adaptation Program tion science, supported by the UN Decade on Ecosystem Restoration. • cooling and shading – reducing exposure of coral reefs to heat and light stress during The UN Decade aims to massively acute events scale-up restoration to combat the cli- • stabilization – adding reef structures and stabilization measures to facilitate coral mate crisis and enhance food security, recovery following disturbances (see Fig. 3) water supplies, and . Most • coral seeding – using natural coral larvae to enhance coral reproduction and reef of the focus will be on land, through recovery following disturbance actions such as replanting trees. These • biocontrol – managing coral predators and competitors to enhance coral survival efforts will help marine ecosystems in • field treatments – increasing coral survival and health following disturbance with probiotics, feeding, medicines or other treatments three ways. First, many coastal ecosys- • seeding with enhanced corals from existing stock – seeding reefs with corals from tems are damaged by muddy water and existing stock that have enhanced performance, to increase coral health and tolerance pollution from degraded agricultural • seeding enhanced corals bred from engineered stock – seeding reefs with corals land, and this will be reduced if there that have enhanced performance derived from synthetic biology and gene editing is more cover. Second, restor- approaches, to increase reef health and tolerance. ing coastal and replanting

28 The Marine Biologist | April 2020 UN Decade on Ecosystem Restoration

Figure 4. Larval restoration trials in the Great Barrier Reef. Image © Ross Miller. forests will improve local into research and development offers also experience the world of wonder water quality as they filter runoff opportunities for new . we have had the privilege to enjoy. from coastal land. Third, restoration Some critics worry that an increasing Dr Ian McLeod (ian.mcleod@jcu. could remove up to 26 gigatonnes of focus on restoration will distract from edu.au) and Dr Maxine Newlands greenhouse gases from the atmosphere, meaningful action on climate change, ([email protected]) at helping to combat climate change, and this is a valid concern. Without TropWATER, James Cook University, the most important threat for marine meaningful and rapid action to reduce Australia. ecosystems such as coral reefs. emissions the future Further reading So what is the role of coral restora- for coral reefs is bleak. Conversely, by McLeod I.M. et al. (2019). Mapping tion in a warming world? First, whilst focussing so much on climate change and Future Priorities for Coral decades of warming as the driver of Restoration and Adaptation Programs. are ‘baked in’, coral Global climate change is coral decline, there 44 pages. Available at www.icriforum. org restoration and adap- the key driver of coral reef is a danger that tation could help pre- decline decision-makers will Boström-Einarsson L. et al. (2020) serve more coral stock give up on other Coral restoration – A systematic review and biodiversity to actions to improve of current methods, successes, failures help corals recover once, or if, tempera- coral reef health, such as improv- and future directions. PLoS ONE 15(1): tures stabilize. Second, in many areas ing local water quality because they e0226631. https://doi.org/10.1371/ such as popular tourism locations, local think reefs are doomed anyway. journal.pone.0226631 reefs are so valuable that it justifies The upcoming decade will be critical Reef Restoration and Adaptation the high cost of restoration. Third, all for the world, and for coral reefs. We Program website https://www. new science and innovation is conten- are responsible for the destruction of gbrrestoration.org/ tious, but coral restoration allows for much of the world’s natural wealth Restoring Seven Iconic Reefs: A citizen scientists, divers and people in just a few lifetimes. Embracing the Mission to Recover the Coral Reefs of who care to get involved in helping, UN Decade on Ecosystem Restora- the https://www.fisheries. and therefore gives hope. Lastly, coral tion on land and at sea, along with noaa.gov/southeast/habitat-conserva- tion/ restoration has largely been driven by urgent action to reduce greenhouse restoring-seven-iconic-reefs-mission- passionate tinkerers, and involving emissions, is an opportunity to turn recover-coral-reefs-florida-keys high-technology and large investments the so the next generation can

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