The damage caused to the Great Barrier Reef by global warming has compromised the capacity of its corals to recover, according to new research published today in Nature.

“Dead corals don’t make babies,” said lead author Professor Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University (JCU). “The number of new corals settling on the Great Barrier Reef declined by 89 percent following the unprecedented loss of adult corals from global warming in 2016 and 2017.”

The unique study measured how many adult corals survived along the length of the world’s largest reef system following extreme heat stress, and how many new corals they produced to replenish the Great Barrier Reef in 2018. The loss of adults resulted in a crash in coral replenishment compared to levels measured in previous years before mass coral bleaching.

“The number of coral larvae that are produced each year, and where they travel to before settling on a reef, are vital components of the resilience of the Great Barrier Reef. Our study shows that reef resilience is now severely compromised by global warming,” said co-author Professor Andrew Baird.

“The biggest decline in replenishment, a 93% drop compared to previous years, occurred in the dominant branching and table coral, Acropora. As adults these corals provide most of the three-dimensional coral habitat that support thousands of other species,” he said.

“The mix of baby coral species has shifted, and that in turn will affect the future mix of adults, as a slower than normal recovery unfolds over the next decade or longer.”

“The decline in coral recruitment matches the extent of mortality of the adult brood stock in different parts of the Reef,” added Professor Hughes. “Areas that lost the most corals had the greatest declines in replenishment.”

“We expect coral recruitment will gradually recover over the next five to ten years, as surviving corals grow and more of them reach sexual maturity, assuming of course that we don’t see another mass bleaching event in the coming decade,” he said.

So far, the Great Barrier Reef has experienced four mass bleaching events due to global warming, in 1998, 2002, and back-to-back in 2016 and 2017. Scientists predict that the gap between pairs of coral bleaching events will continue to shrink as global warming intensifies.

“It’s highly unlikely that we could escape a fifth or sixth event in the coming decade,” said co-author Professor Morgan Pratchett.

“We used to think that the Great Barrier Reef was too big to fail – until now,” he said.

“For example, when one part was damaged by a cyclone, the surrounding reefs provided the larvae for recovery. But now, the scale of severe damage from heat extremes in 2016 and 2017 was nearly 1500km—vastly larger than a cyclone track.”

Professor Pratchett added that the southern reefs that escaped the bleaching are still in very good condition, but they are too far away to replenish reefs further north.

“There’s only one way to fix this problem,” says Hughes, “and that’s to tackle the root cause of global heating by reducing net greenhouse gas emissions to zero as quickly as possible.”

PAPER

Hughes T, Kerry J, Baird A, Connolly S, Chase T, Dietzel A, Hill T, Hoey A, Hoogenboom M, Jacobson M, Kerswell A, Madin J, Mieog A, Paley A, Pratchett M, Torda G, & Woods R (2019). ‘Global warming impairs stock–recruitment dynamics of corals’. Nature: http://dx.doi.org/10.1038/s41586-019-1081-y

PHOTOS & VIDEO

A selection of photos and videos relating to the study is available here. Please note that any use of this imagery MUST carry the credit given. In addition, permission must be obtained from the ARC Centre of Excellence for Coral Reef Studies for any use beyond this story.

The Australian Academy of Science have produced a video based on the study. The files are available to embed in online stories at the Dropbox hyperlink above, and the YouTube embed link is here. 

CONTACTS FOR INTERVIEWS
 
Prof Terry Hughes (Pacific Coast Time Zone, USA)
Director, ARC Centre of Excellence for Coral Reef Studies
Phone: +61 (0)400 720 164
Email: terry.hughes@jcu.edu.au

Prof Andrew Baird (Eastern Australia Time Zone)
ARC Centre of Excellence for Coral Reef Studies
Phone: +61 (0)7 4781 4857
Mobile: +61 (0)400 289 770
Email: andrew.baird@jcu.edu.au

Prof Morgan Pratchett (Eastern Australia Time Zone)
ARC Centre of Excellence for Coral Reef Studies
Phone: + 61 (0)7 4781 5747
Mobile: +61 (0)488 112 295
Email: morgan.pratchett@jcu.edu.au

FOR FURTHER INFORMATION

Melissa Lyne (Eastern Australia Time Zone)
Media Manager, ARC Centre of Excellence for Coral Reef Studies
Phone: +61 (0) 415 514 328
Email: melissa.lyne@jcu.edu.au

Leading coral reef scientists say Australia could restore the Great Barrier Reef to its former glory through better policies that focus on science, protection and conservation.

In a paper published in the journal Nature Climate Change, the authors argue that all the stressors on the Reef need to be reduced for it to recover.

An Australian Government report into the state of the Great Barrier Reef found that its condition in 2014 was “poor and expected to further deteriorate in the future”. In the past 40 years, the Reef has lost more than half of its coral cover and there is growing concern about the future impacts of ocean acidification and climate change.

“We need to move beyond the gloom and doom to identify how the decline of the Great Barrier Reef can be turned around,” says co-author Professor Terry Hughes from the ARC Centre of Excellence for Coral Reef Studies at James Cook University (JCU).

“Our paper shows that every major stressor on the Reef has been escalating for decades – more and more fishing, pollution, coastal development, dredging, and now for the past 20 years we’re also seeing the impacts of climate change.”

“We now have a very good handle on why the Great Barrier Reef is in trouble,” adds co-author, Jon Brodie from the Centre for Tropical Water and Aquatic Ecosystems Research at JCU.

“The challenge is to use that scientific knowledge to prevent further damage and give the Reef some breathing space that would allow it to recover.

Co-author, Jon Day, also from the ARC Centre for Coral Reef Studies at JCU says an obvious first step is to prevent unsustainable growth in each of the stressors to reduce their cumulative impact.

“If that means less dredging, less coal mining and more sustainable fishing, then that’s what Australia has to do. Business as usual is not an option because the values for which the Reef was listed as World Heritage are already deteriorating, and will only get worse unless a change in policy occurs.”

The authors say that as countries around the world move to curb global carbon emission, Australia has an opportunity to transition away from fossil fuels and to limit the development of huge coal ports alongside the Great Barrier Reef World Heritage Area.

“No-one is saying Queensland should not have ports – however, what we are saying is that all developments within, and adjacent to, the Great Barrier Reef need to be far more sustainable in the way that they are developed and operated, especially because they adjoin a World Heritage Area, “says Jon Day.

The authors agree that no one wants to see the Great Barrier Reef placed on UNESCO’s ‘World Heritage Area In-Danger’ list.

The Great Barrier Reef needs breathing space to recover. Image courtesy of State of Queensland

“The economic case for better protecting the Great Barrier Reef is very clear – it supports more than 60,000 jobs, mostly in Reef-related tourism,” says Professor Hughes.

The scientists have outlined a six-point plan they believe will restore the Great Barrier Reef, including;

• A return to the former emphasis on conservation and protection of the Great Barrier Reef.
• Australia taking a lead role in tackling climate change by transitioning away from fossil fuels.
• Permanent legislative bans on dumping both capital and maintenance dredge spoil within the World Heritage area.
• An overhaul of the environmental impact assessment process for new developments
• The Great Barrier Reef Marine Park Authority (GBRMPA) reinstated as the agency responsible for all aspects of the Great Barrier Reef, including fishing and ports. A 50-year plan and adequate funding for the use of the catchment designed to reduce greenhouse gas emissions and agricultural run off.

Jon Brodie says Australia is starting to reduce runoff of nutrients, sediments and pesticides from land into the World Heritage Area, and is improving regulations for dumping capital dredge-spoil, but much more action is needed.

“These efforts are a welcome step in the right direction, but they will need much better resourcing in order to substantially reduce pressures on the World Heritage Area.”

The authors say the global community must make it clear that they want more effective policy action to ensure the Great Barrier Reef is restored for current and future generations.

“This paper raises awareness of the untapped opportunities to incorporate science into better policy to ensure we still have a magnificent Great Barrier Reef in the future,” Terry Hughes adds.

~~~

Paper

‘Securing the future of the Great Barrier Reef’, by Terry P. Hughes, Jon C Day and Jon Brodie is published in the journal, Nature Climate Change http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2604.html

Images/video/audio grabs
http://youtu.be/nKBM2kjpTKw
https://www.dropbox.com/sh/qwl130fzebt8hc2/AADH4nOl8bhkiH3utc0sV8hQa?dl=0

Contacts

Prof Terry Hughes, terry.hughes@jcu.edu.au, +61 (0) 400 720 164

Jon Brodie – Centre for Tropical Water and Aquatic Ecosystems Research, James Cook University, jon.brodie@jcu.edu.au, +61 (0) 407127030

Jon Day – jon.day@my.jcu.edu.au, +61 (0) 419 404 167 (Jon will be in the US)

Eleanor Gregory, Communications, eleanor.gregory@jcu.edu.au, +61 (0) 428 785 895

Professor Terry Hughes discusses the paper.

The world’s coral reefs are not doomed – provided governments and communities take the urgent and necessary actions to preserve them.

That’s the message from eminent Australian marine scientist and recipient of this year’s Darwin Medal Professor Terry Hughes in his keynote address to the 11th International Coral Reef Symposium, being held at Fort Lauderdale, Florida, USA from June 7-11.

The world’s coral reefs are not doomed – provided governments and communities take the urgent and necessary actions to preserve them.

Prof. Hughes is the Director of the Australian Research Council Centre of Excellence for Coral Reef Studies, based at James Cook University, Townsville, Australia.

“The global coral reef crisis is really a crisis of governance. Many of the measures put in place are failing, not because of biology, but because of lack of support from local people and governments,” he says.

“For example many no-take marine reserves have been set up round the world by non-government organisations – but nearly all of them are proving unsuccessful because they ignore the needs of the local population and have failed to win their backing.”

Professor Hughes called on coral reef researchers worldwide to work harder at the societal and economic aspects of protecting the oceans and their living resources.  Good biology alone is not enough. “The reefs are not doomed if we all do the right thing,” he asserts.

On land, environmental science now accepts that people are a part of the ecosystem and that sustainable solutions have to include them and their needs. At sea, he warns, the tendency is still to try to solve the problem by excluding people entirely from marine resources.

“If you take the Coral Triangle bounded by Indonesia, Borneo and Papua New Guinea, there are around 200 million people who depend on it for their livelihoods.  You cannot ignore the needs of these people in devising ways to protect their marine diversity.”

Prof. Hughes argues that traditional conservation is backward-looking, often seeking to restore the pristine wilderness of yesterday. It treats people and nature as separate, and wishes that the world could be static. This is incompatible with the reality of a surging human population and its demand for protein, as well as the constant evolution and change in natural systems.

“You cannot simply remove the needs of hundreds of millions of people from the equation. You have to design your conservation measures so that they also address things like ecosystem services which the ocean provides to humans, and sustainable livelihoods for people who depend on the sea, as well as protecting biodiversity.”

He says many no-take reserves were also poorly designed because they ignored the need to also look after the surround areas where fishing was still allowed. “These areas may be less species-rich than the protected zone, but they play a vital role in connecting protected areas together, and have to be managed in concert with them.”

Professor Hughes warns that the world is entering a transitional period in which humanity can choose whether to cross, or to avoid, tipping-points from which there is no recovery – at least within human time-spans.

“We need to adopt a forward-looking approach, to actively navigate to the “place” we want to be in terms of our environment, land and sea,” he says. “This means accepting that we have changed some things permanently, and that we can choose to manage a new state – or to allow the resource to continue to decline to point from which it may not recover.”

Such a tipping point may be evident in the coral reef systems of the Caribbean which largely collapsed and have now failed to recover, mainly because the corals can no longer regenerate fast enough to cope with overfishing, hurricanes and other impacts, he says. The reefs are overgrown with weed and the coral broodstock so reduced it cannot compensate for new impact losses.

At ICRS this year Professor Hughes will receive the International Society for Reef Studies’ highest honour, the Darwin Medal, for his outstanding contribution to marine and coral science and to the growing appreciation of the importance of the resilience of natural systems, a scientific view in which he was a leading player.

More information:
Professor Terry Hughes, CoECRS and JCU, ph +61 400 720 164 (mobile)
Liz Neeley, ICRS media , +1 425 301 8019
Louise Taylor, CoECRS, + 61 7 4781 4000
Jim O’Brien, James Cook University Media Office, +61 7 4781 4822

International Coral Reef Symposium:
http://www.nova.edu/ncri/11icrs/media_newsroom.html