1

People and ecosystems

Understanding of the links between coral reef ecosystems, the goods and services they provide to people, and the wellbeing of human societies.

2

Ecosystem dynamics: past, present and future

Examining the multi-scale dynamics of reefs, from population dynamics to macroevolution

3

Responding to a changing world

Advancing the fundamental understanding of the key processes underpinning reef resilience.

Coral Bleaching

Coral Bleaching

Coral Reef Studies

ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia

Phone: 61 7 4781 4000
Email: info@coralcoe.org.au

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New DNA techniques are being used to understand how coral reacted to the end of the last ice age in order to better predict how they will cope with current changes to the climate.

James Cook University’s Dr Ira Cooke was senior author of the study. He said when corals become stressed they often bleach and die, but not all corals experience stress equally.

“This is often due to genetic differences between species, but it’s usually very difficult to determine which genes are responsible. In situations where the differences evolved relatively recently – thousands not millions of years ago – it’s much easier to do so,” said Dr Cooke.

He said the end of the last ice age is relatively recent in evolutionary terms and it sometimes forced corals to adapt to stresses similar to those projected under future climate change.

“Until now it hasn’t been possible to look at this period in coral evolution because most of the techniques available have provided information about much older events. But by sequencing the whole genomes of many individuals within a single species we have now been able to access this crucial period of coral evolutionary history,” said Dr Cooke.

JCU PhD candidate Jia Zhang, lead author of the study, said sea-level change has reshaped the Kimberley coral communities many times in the past.

“This study examines how these historical changes have influenced coral population sizes, how far they disperse, and their ability to adapt,” said Ms Zhang.

She said the researchers compared the genomes of corals from the inshore Kimberley with those inhabiting more benign offshore locations (Ashmore Reef and Rowley Shoals).

“We found there were clear genetic distinctions, akin to races, between corals from the three locations we studied but most obviously between the inshore and offshore reefs, and that these genetic groups had arisen around the time the last ice-age ended.

“This was when sea levels rose dramatically allowing corals to colonise the Kimberley region, and to re-establish themselves on the tops of offshore atolls,” said Ms Zhang.

Co-author of the study, Dr Zoe Richards from Curtin University’s School of Molecular and Life Sciences said as the sea-level rose between 20 and 10 thousand years ago, corals dispersed to new habitats.

“But only those individuals with the right genetic makeup were able to survive. This selective process is visible in the genomes and tells us which genes were important for survival,” said Dr Richards.

She said corals from the Kimberley had tell-tale patterns in their genomes revealing genes that were modified through natural selection around the time of the last ice-age when they colonised this tough inshore habitat.

Dr Cooke said one specific type of genes called peroxinectins have been under especially strong and recent evolutionary pressure (natural selection) in inshore Kimberley corals.

“These genes clearly evolved different versions in inshore corals and it’s likely that this helps them cope with the extreme environmental conditions there. These genes provide a roadmap to help further understand how corals can survive turbid, hot and exposed conditions like those in the Kimberley”

This study was funded by ARC Linkage Project LP160101508.

PAPER

Zhang J, Richards Z, Adam A, Cheong XC, Shinzato C, Gilmour J, Thomas L, Strugnell J, Miller D, Cooke I. 2022. ‘Evolutionary responses of a reef-building coral to climate change at the end of the last glacial maximum’. Molecular Biology and Evolution. DOI: https://doi.org/10.1093/molbev/msac201

IMAGES

A selection of images can be used for media stories with credit to the photographer as stated in the file name. Please note these are for single use with this story only, not for any other story. No archival permissions are granted.

CONTACT

Dr Ira Cooke (Townsville, AEST)
P: +61 (0)429 105 999
E: ira.cooke@jcu.edu.au

Dr Zoe Richards (Perth, AWST)
P: +61 (0)487 213 021
E: zoe.richards@curtin.edu.au

Ms Jia Zhang (Townsville, AEST)
P: +61 (0)431 819 701
E: jia.zhang2@my.jcu.edu.au

Prof David Miller (Townsville, AEST)
P: +61 (0)418 671 768
E: david.miller@jcu.edu.au

Researchers working with stakeholders in the Great Barrier Reef region have come up with ideas on how groups responsible for looking after the reef can operate more effectively when the next bleaching event arrives.

Dr Michele Barnes is a Senior Research Fellow at James Cook University’s Centre of Excellence for Coral Reef Studies. She said in 2016 and 2017 the reef experienced unprecedented back-to-back mass coral bleaching – challenging its guardians’ abilities to protect it.

“Our collaborative research was squarely aimed at improving governance responses to extreme climate events in the GBR region and potentially other regions around the world,” said Dr Barnes.

The team interviewed 32 key individuals representing government, non-profits, research institutions, and the tourism, fishing, and aquaculture industries. The organisations deal with coral health, water quality, tourism and fishing.

“We wanted to understand catalysts and barriers to actions being taken across the region in response to coral bleaching, and participants’ hopes for future action,” said Dr Barnes.

The researchers found five major categories of activity for those involved in the wake of coral bleaching: assessing the scale and extent of bleaching, sharing information, communicating bleaching to the public, building local resilience, and addressing global threats.

“These actions were helped and hindered by a range of factors. For instance, some people were hindered in responding because information on the bleaching was scattered and not well integrated, there were conflicts and a lack of respect across certain groups, and community involvement was lacking in some cases” said co-author Amber Datta, a PhD candidate based at James Cook University and the University of Montana.

Working with a group of local stakeholders in the Great Barrier Reef, the team identified several ways to improve responses to future crises. These improvements include improving coordination, strengthening relationships between groups, and empowering and recognizing Traditional Owners as leaders of their Sea Country rather than stakeholders (see attached graphic for more details).

Dr. Barnes said “The new approaches should help to improve responses to future crisis events, but effective responses will depend on the willingness of diverse groups to negotiate a shared path forward, and ultimately on international and national commitments to address the root cause of climate change”.

PAPER

Barnes M.L., Datta A., Morris S., Zethoven I.  2022. ‘Navigating climate crises in the Great Barrier Reef’. Global Environmental Change. DOI: 10.1016/j.gloenvcha.2022.102494

CONTACT

Dr Michele Barnes (Townsville, AEST)

M: +61 (0)408 677 570
E: michele.barnes@jcu.edu.au

Amber Datta (Townsville, AEST)
M (AU): +61 (0)456 426 248
E: amber.datta@my.jcu.edu.au

A new study has delivered a stark warning about the impacts of urban growth on the world’s coral reefs.

As coastal developments expand at pace around the world, a year-long study of coral on a reef close to a rapidly growing urban centre in the Middle East has found they have become severely disturbed at the molecular level – with implications for all such corals worldwide.

Professor David Miller is a geneticist at James Cook University’s Centre of Excellence for Coral Reef Studies (Coral CoE). He said coral reefs are in global decline due to climate change and anthropogenic influences.

“Near coastal cities or other densely populated areas, coral reefs face a range of challenges in addition to that of climate change. To investigate the impacts of urban proximity on corals, we conducted a year-long study in the Gulf of Aqaba in the Red Sea, comparing corals close to an urban area to corals from a near-by non-urban area,” said Professor Miller.

He said the Gulf of Aqaba is an ideal study site because its corals have a remarkable level of thermal tolerance. This means scientists can isolate the effects of urban environments such as unpredictable and fluctuating levels of nutrients, hormone mimics and other organic contaminants, local pollution and chronic exposure to noise and light pollution, against a background of relatively limited potential impacts of ocean warming caused by climate change.

“Essentially, we found that in the area close to urban development, every natural biological rhythm is messed up in the coral host, that the algal symbionts are seriously under-performing and that the microbiome is also out of kilter. These corals are comprehensively disturbed, despite appearances,” said Professor Miller.

He said for instance, bacteria on the coral peaked at different moon-phases between the urban and non-urban coral, while reproductive processes, which are all aligned with the moon phase, were wiped out in the urban corals.

“This study is significant because while a lot of work had previously been done on the impacts of individual stressors on corals, no one had previously looked at how corals in the wild react to real-world complex combinations of stressors,” said Dr. Inga Steindal, also of the Coral CoE.

She said the findings were alarming, given the recent and planned extensions of urban centres near tropical coastlines.

There has been continuous growth of cities such as Jakarta, Singapore and Hong Kong, but also major new developments have occurred or are planned that are likely to directly impact coral reefs in the near future. The population of the Chinese coastal city of Shenzhen alone has grown from less than a million in 1990 to more than 12.5 million in 2021.

“With that kind of expansion and with more to come, things don’t look too good for the future of corals in those regions,” said Professor Miller.

PAPER

Rosenberg Y., Blecher N.S., Lalzar M., Yam R., Shemesh A., Alon S., Perna G., Cardenas A., Voolstra C.R., Miller D.J., Levy O.  2022. ‘Urbanisation comprehensively impairs rhythms in coral holobionts’. Global Change Biology. DOI: 10.1111/gcb.16144

CONTACT

Professor David Miller (Townsville, AEST)

M: +61 (0)419 671 768
E: david.miller@jcu.edu.au

Dr. Inga Steindal (Townsville, AEST)
M: +61 (0)481 300 921
E: inga.steindal@jcu.edu.au

Alarming new research shows global warming of 1.5°C relative to pre-industrial levels will be catastrophic for almost all coral reefs – including those once thought of as refuges.

Associate Professor Scott Heron from James Cook University was part of the study. He said the team of scientists used the latest generation of climate model projections to predict future thermal exposure of shallow-water coral reefs around the globe.

“We identified thermal refuges – places where it’s thought coral reefs have a good chance of surviving warming oceans due to things like consistent upwelling of cool deep waters – at a resolution of only 1 km,” said Dr Heron.

He said the scientists found that the refuges will provide almost no escape – only 0.2%, or one fifth of one percent, of coral reefs globally are projected to avoid frequent bleaching-level heat stress under a 1.5°C climate warming scenario.

“This means corals worldwide are at even greater risk from climate change than previously thought, especially as limiting warming to 1.5°C is looking increasingly unlikely,” said Dr Heron.

He said coral recovery following extensive thermal stress-induced mortality depends on local conditions, but science indicates it requires at least 10 years for coral communities to re-establish ecosystem functions.

“Most coral reefs won’t have time to recover between bleaching events,” said Dr Heron.

Though small in number, there are some reef locations that may persist due to other factors.

“In addition to locations where heat exposure events will be less frequent, like in French Polynesia and southern Indonesia, there are other ‘hope sites’ that have high variability in temperatures. Corals in these locations, such as the Eastern Pacific, may be better able to cope with temperature extremes,” said Adele Dixon, lead author of the study from the University of Leeds in the UK.

Dr Heron added that the scientists wanted to highlight that climate change effects are already impacting ecosystems in many areas of the world and will worsen, even at the 1.5°C of global warming set as a target in international agreements. This includes potential impacts of heat stress this year on the Great Barrier Reef and off Western Australia.

“This analysis confirms that significant action on greenhouse gas emissions is urgent and needed this decade. We also need to ramp up local actions to help reefs survive through already predicted impacts. Promoting reef resilience, adaptation to higher temperatures and facilitating migration will be vital strategies to secure their survival,” said Dr Heron.

PAPER

Dixon A.M., Forster P.M., Heron S.F., Stoner A.M.K., Beger M. 2022. ‘Future loss of local-scale thermal refugia in coral reef ecosystems’. PLOS Climate. DOI: https://doi.org/10.1371/journal.pclm.0000004

IMAGES

A selection of images can be used for media stories with credit to the photographer as stated in the file name. Please note these are for single use with this story only, not for any other story. No archival permissions are granted.

CONTACT

Associate Professor Scott Heron (Townsville, AEST)
P: +61 (0)404 893 420
E: scott.heron@jcu.edu.au

Scientists have taken a rare look at the depths of the Great Barrier Reef and have discovered they’re teeming with a kaleidoscope of life.

And they say conservation planners should take into account their findings to better protect the international icon.

ARC Centre of Excellence for Coral Reef Studies at James Cook University PhD candidate Tiffany Sih led the study, which used Baited Remote Underwater Video Stations (BRUVS) and multi-beam sonar to examine the reef down to 260 metres.

“The ecology of deeper habitats along the Great Barrier Reef has rarely been investigated. While we know habitat like coral is important for shallower fish species, there was little understanding of how important reef habitat is to fish in deeper environments,” said Ms Sih.

She said the lack of information was due to the expense of doing research at these depths, which often requires specialist divers, remotely operated submersibles or mini-submarines.

Instead, the team sampled 48 sites between 54 and 260 metres deep in the central GBR using sonar and a relatively simple BRUVS rig, which attracts fish with bait and films them.

“We found the ecology of deeper reef fish communities is fundamentally different from those found at shallower depths. Depth and reef composition was important, but habitat preferences clearly had a role in determining the distribution of fish species.

Both the living components of the habitat – such as algae, soft corals and sponges, as well as big boulders or mud flats – contribute to the structure and complexity of the reef, which has an effect on what kind of fish you find there,” said Ms Sih. 

She said when the rules around fishing in the Great Barrier Reef Marine Park were determined over a decade ago, less environmental data was available for the deeper habitats.

“They took into account what they did not know, and allowed for some uncertainty, by designating some of the deeper areas as no-take zones and zones where certain types of fishing, like bottom-trawling, were banned. But now the technology exists where we can map the deeper areas and fully document the fish community,” said Ms Sih.

She said that in the future it will be important to compare deeper fish communities in the Great Barrier Reef Marine Park and to consider deeper reefs as essential neighbourhoods where communities of fish thrive.

Contact: Tiffany Sih (now located in Ocean Grove, Victoria)
M: 0432 528 008
E: Tiffany.Sih@my.jcu.edu.au

Professor Mike Kingsford (Professor Kingsford works at JCU’s Townsville campus).
M: 0438 731 694
E: Michael.kingsford@jcu.edu.au
T: 07 4781 4312

Paper: Sih TL, Daniell JJ, Bridge TC, Beaman RJ, Cappo M, Kingsford MJ, (2019). Deep-Reef Fish Communities of the Great Barrier Reef Shelf-Break: Trophic Structure and Habitat Associations. Diversity. 11(2):26.

Link to journal here

Video here

Rat control should be considered an urgent conservation priority on many remote tropical islands to protect vulnerable coral reefs, according to an international team of scientists.

New research has confirmed that invasive rats decimate seabird populations, with previously unrecognised consequences for the extensive coral reefs that encircle and protect these islands.

Invasive predators such as rats – which feed on bird eggs, chicks, and even adults birds – are estimated to have decimated seabird populations within 90% of the world’s temperate and tropical island groups, but until now the extent of their impact on surrounding coral reefs wasn’t known.

The new study, led by researchers at Lancaster University (UK), ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University and Dalhousie University (Canada), examined tropical ecosystems in the northern atolls of the Chagos Archipelago to uncover how rats have impacted surrounding reefs.

Lead author Professor Nick Graham of Lancaster University, said: “Seabirds are crucial to these kinds of islands because they are able to fly to highly productive areas of open ocean to feed. They then return to their island homes where they roost and breed, depositing guano – or bird droppings – on the soil.  This guano is rich in the nutrients, nitrogen and phosphorus.  Until now, we didn’t know to what extent this made a difference to adjacent coral reefs.”

An extraordinary set of remote tropical islands in the central Indian Ocean, the Chagos islands provided a perfect ‘laboratory’ setting as some of the islands are rat-free, while others are infested with black rats – thought to have been introduced in the late 1700s and early 1800s. This unusual context enabled the researchers to undertake a unique, large-scale study directly comparing the reef ecosystems around these two types of islands.

By examining soil samples, algae, and counting fish numbers close to the six rat-free and six rat-infested islands, scientists uncovered evidence of severe ecological harm caused by the rats, which extended way beyond the islands and into the sea.

Rat-free islands had significantly more seabird life and nitrogen in their soils, and this increased nitrogen made its way into the sea, benefiting macroalgae, filter-feeding sponges, turf algae, and fish on adjacent coral reefs.

Fish life adjacent to rat-free islands was far more abundant with the mass of fish estimated to be 50% greater.

The team also found that grazing of algae – an important function where fish consume algae and dead coral, providing a stable base for new coral growth – was 3.2 times higher adjacent to rat free islands.

“These results not only show the dramatic effect that rats can have on the composition of biological communities, but also on the way these vulnerable ecosystems function (or operate),” said co-author Dr Andrew Hoey from Coral CoE at James Cook University.

“Critically, reductions in two key ecosystem functions (grazing and bioerosion) will likely compromise the ability of these reefs to recover from future disturbances.”

Professor Graham said: “The results of this study are clear. Rat eradication should be a high conservation priority on oceanic islands. Getting rid of the rats would be likely to benefit terrestrial ecosystems and enhance coral reef productivity and functioning by restoring seabird derived nutrient subsidies from large areas of ocean. It could tip the balance for the future survival of these reefs and their ecosystems.”

Associate Professor Aaron MacNeil from Dalhousie University said: “These results show how conservation can sometimes be a bloody business, where doing right by the ecosystem means there is a time to kill. For these invasive rats, that time is now.”

The paper “Seabirds enhance coral reef productivity and functioning in the absence of invasive rats,” is published in the prestigious journal Nature.

The research was led by  Lancaster University (UK) with the ARC Centre of Excellence for Coral Reef Studies (Australia), Dalhousie University (Canada), Department of Biodiversity, Conservation and Attractions, Perth, Australia, University of Western Australia, Australia, Zoological Society of London, UK, University of Exeter, UK, and the International Council for the Exploration of the Sea, Denmark.

 

Note to Editors

Additional key points from the study:

Citation: Graham, NAJ, Wilson, SK, Carr, P, Hoey, AS, Jennings, S, MacNeil, MA (2018), Seabirds enhance coral reef productivity and functioning in the absence of invasive rats. Nature 559: 250-253 

Link to video and images here. Please credit as marked.

Contacts for interviews 

Prof Nick Graham
Lancaster University, Lancaster Environment Centre
Lancaster, U.K.
P: +44 (0) 7479 438 914 (GMT/UTC)
E: nick.graham@lancaster.ac.uk

Dr Andrew Hoey
ARC Centre of Excellence for Coral Reef Studies at James Cook University
Townsville, QLD AUSTRALIA
P: +61 7 4781 5979 (AEST/UTC +10)
E: andrew.hoey1@jcu.edu.au

A/Prof Aaron MacNeil
Dalhousie University, Department of Biology
Halifax, NS, CANADA
P: +1 902 402-1273 (ADT/UTC -3)
E: a.macneil@dal.ca

For further information

Beth Broomby (U.K.)
Head of Press Office, Lancaster University
P: +44 (0) 1524 593719, +44 (0) 7881 813 831 (GMT/UTC)
El: b.broomby@lancaster.ac.uk

Catherine Naum (AUSTRALIA)
Communications Manager, ARC Centre of Excellence for Coral Reef Studies
P: +61 (0) 7 4781 6067, +61 (0) 428 785 895 (AEST/UTC +10)
E: catherine.naum1@jcu.edu.au

Niecole Comeau (CANADA)
Communications, Faculty of Science, Dalhousie University
P: +1 (902) 494-8443, +1 (902) 223-2446 (ADT/UCT -3)
E: niecole.comeau@dal.ca

Reports in recent years that marine protected areas (MPAs) aren’t effective in saving coral reefs from the damaging effects of global climate change have led some to argue that such expensive interventions are futile. But a study that spanned 700 kilometers of the eastern Caribbean reveals that MPAs can, indeed, help coral reefs.

An international team of scientists from the University of Maine, USA (UMaine) and the ARC Centre of Excellence for Coral Reef Studies at The University of Queensland, Australia (Coral CoE) conducted research on the leeward islands of the Caribbean and discovered that local reef protection efforts can work — contradicting several previous studies.

Local fisheries management resulted in a 62 percent increase in the density of young corals, which improves the ecosystem’s ability to recover from major impacts like hurricanes and coral bleaching, according to the team’s findings, published in Science Advances, a journal of the American Association for the Advancement of Science.

“MPAs can help coral reefs, but studies to the contrary just weren’t measuring the right things at the right scales,” says lead author and Professor of Marine Biology, Bob Steneck, of UMaine.

“The idea behind MPAs is that, by reducing fishing pressure, you increase the number of seaweed-eating fish, and they decrease the amount of harmful seaweed, which makes it easier for baby corals to get started and thrive on the reef. But coral reefs are complicated, and lots of other things can affect fish numbers, their ability to control the growth of algae and the ability of corals to take advantage of this.”

“Taking field measurements on coral reefs is time consuming, so many researchers are forced to take shortcuts and use simple, widely available data to analyse how reefs respond to protection,” says study co-author Professor Peter Mumby of Coral CoE.

“While it sounds obvious, we show that our ability to detect the benefits of MPAs on corals improves dramatically when you take more detailed measurements,” Prof Mumby says.

“For example, a simple option is to count the number of herbivorous fishes. But if, instead, you estimate how intensively these fishes feed, you obtain a much clearer and compelling insight.”

There is no management panacea for any ecosystem, and especially not for coral reefs, Prof Steneck notes.

“Certainly, stresses on coral reefs from climate and atmospheric changes are serious and beyond direct management control. However, we suggest that local management measures can bolster the recovery of corals after damaging events and, eventually, improve their overall condition.”

Doug Rasher of Bigelow Laboratory for Ocean Science in East Boothbay, Maine, adds: “What we show is that relatively small changes can nudge this ecosystem toward one that can maintain and sustain itself.”

The research team, which also included researchers from James Cook University (Australia) and RARE (USA), concludes that the best way to measure the effectiveness of reef conservation is by using a suite of metrics, including the number of fish, amount of seaweed and the number of baby corals, rather than just one indicator of reef health.

This research was partially funded by the National Geographic Society.

Multimedia resources available here.

Video abstract courtesy of University of Maine here.

Citation: Steneck, RS, Mumby, PJ, MacDonald, C, Rasher, DB, Stoyle, G (2018). Attenuating effects of ecosystem management on coral reefs. Science Advances Vol. 4, no. 5, doi: 10.1126/sciadv.aao5493

 

Contact:

Robert Steneck, steneck@maine.edu (EST)

Peter Mumby, p.j.mumby@uq.edu.au (AEST)

 

For More Information:

Margaret Nagle, nagle@maine.edu (EST)

Catherine Naum, catherine.naum1@jcu.edu.au (AEST)

Jan King, j.king@uq.edu.au (AEST)

An international team of scientists has developed a strategy to boost people’s ability to adapt to climate change, revealed in a new study published today in the prestigious journal, Nature Climate Change.

“Millions of coastal people in the tropics have been affected by the global coral bleaching event that unfolded over the previous two years. We need to find ways to help these people adapt to change,” said Professor Joshua Cinner from the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

A group of social scientists from the USA, Australia, UK, and Chile, led by Prof. Cinner, have pooled their experience, and lessons from hundreds of research and development projects, to highlight five keys ways to build up the adaptive capacity of people living in the coastal tropics. These include:

1. Ensuring that people have the assets to draw upon in times of need. These assets can include household wealth or public goods such as health services, but they need to be developed in ways that don’t exacerbate existing inequalities;
2. Providing the flexibility to change. “Having some flexibility can enable people to minimise losses or even take advantage of climate-related change,” said Prof. Eddie Allison from the University of Washington, USA. “For example, fishers might need to change fishing grounds or target new species.”
3. Learning about climate change and adaptation options. “People need to learn about new techniques and strategies that can help them cope with changing circumstances,” said Prof. Katrina Brown at the University of Exeter, UK.
4. Investing in social relationships. “The formal and informal relationships that people have with each other and their communities can help them deal with change by providing social support and access to both knowledge and resources,” said Prof. Cinner.
5. Empowering people to have a say in what happens to them. “We also need to ensure that people have the ability to determine what is right for them,” said Prof. Brown.

The paper “Building adaptive capacity to climate change in tropical coastal communities,” will be published in the February 1 issue of Nature Climate Change, and is available online today.

Citation: Cinner JE, Adger WN, Allison EH, Barnes ML, Brown K, Cohen PJ, Gelcich S, Hicks CC, Hughes TP, Lau J, Marshall NA, Morrison TH (2018) Building adaptive capacity to climate change in tropical coastal communities. Nature Climate Change 8:117-123

Link to video and images here. Please credit as marked.

Contacts:

Australia: Prof. Josh Cinner.
E: Joshua.cinner@jcu.edu.au
M: +61(0)417714138

UK: Prof. Katrina Brown.
E: Katrina.Brown@exeter.ac.uk

North America (USA): Prof. Eddie Allison.
E: eha1@uw.edu
M: +1 206 859 3438 (mobile)

Latin America (Chile): Dr. Stefan Gelcich
E: sgelcich@bio.puc.cl
P: +569 9577 8574

For more information:

Catherine Naum
Communications Manager
ARC Centre of Excellence for Coral Reef Studies at James Cook University
Townsville, QLD AUSTRALIA
P: +61 (0)7 4781 6067
M: +61 (0) 428 785 895 (AEST/UTC +10)
E: Catherine.Naum1@jcu.edu.au

New research into the impact of climate change has found that warming oceans will cause profound changes in the global distribution of marine biodiversity.

In a study published in the journal Nature Climate Change an international research team modelled the impacts of a changing climate on the distribution of almost 13 thousand marine species, more than twelve times as many species as previously studied.

The study found that a rapidly warming climate would cause many species to expand into new regions, which would impact on native species, while others with restricted ranges, particularly those around the tropics, are more likely to face extinction.

Professor John Pandolfi from the ARC Centre of Excellence for Coral Reef Studies at the University of Queensland says global patterns of species richness will change significantly, with considerable regional variability.

“This study was particularly useful because it not only gave us hope that species have the potential to track and follow changing climates but it also gave us cause for concern, particularly in the tropics, where strong biodiversity losses were predicted,” says Professor Pandolfi.

“This is especially worrying, and highly germane to Australia’s coral reefs, because complementary studies have shown high levels of extinction risk in tropical biotas, where localized human impacts as well as climate change have resulted in substantial degradation.”

To model the projected impact of climate change on marine biodiversity, the researchers used climate-velocity trajectories, a measurement which combines the rate and direction of movement of ocean temperature bands over time, together with information about thermal tolerance and habitat preference.

They say the analysis provides the simplest expectation for the future distribution of marine biodiversity, showing recurring spatial patterns of high rates of species invasions coupled with local extinctions.

Professor Elvira Poloczanska from CSIRO says, “This study shows how climate change will mix up biodiversity patterns in the ocean. Ecological communities which are currently distinct, will become more similar to each other in many regions by the end of the century”

Dr David Schoeman from the University of the Sunshine Coast says the model suggests that there is still time to act to prevent major climate-related extinctions outside of the topics.

“Results under a scenario in which we start actively mitigating climate change over the next few decades indicates substantially fewer extinctions than results from a business-as-usual scenario,” Dr Schoeman says.

“Possibly more worrying, though, is the imminent development of novel biotic assemblages. We have little idea of how these new combinations of species in ocean systems around the world will affect ecosystem services, like fisheries. We should be prioritising ecological research aimed specifically at addressing this question.”

Professor Pandolfi warns the resultant novel combinations of resident and migrant species will present unprecedented challenges for conservation planning.

“Above all, this study shows the broad geographic connections of the effects of climate change – conservation efforts need to be facilitated by cooperation among countries to have any real chance of combating the potentially severe biodiversity losses that a changing climate might impose.”

 ~~~

Paper

The paper, Climate velocity and the future of global redistribution of marine biodiversity by Jorge Garcia Molinos, Benjamin S. Halpern, David S. Schoeman, Christopher J. Brown, Wolfgang Kiessling, Pippa J. Moore, John M. Pandolfi, Elvira S. Poloczanska, Anthony J. Richardson and Michael T. Burrows is published in the journal Nature Climate Change http://dx.doi.org/10.1038/nclimate2769

Contact
Professor John Pandolfi, j.pandolfi@uq.edu.au, +61 (0) 400 982 301
Professor Elvira Poloczanska, Elvira.poloczanska@csiro.au, +61 (0) 428 741 328
Dr David Schoeman, dschoema@usc.edu.au, +61 (0) 423 982 898
Eleanor Gregory (media), eleanor.gregory@jcu.edu.au

A simple test of the number of fish living on a coral reef can be used as a roadmap to restore degraded reefs and fishers’ livelihoods according to a global study published in the journal Nature.

An international team of marine scientists surveyed more than 800 coral reefs worldwide to develop a diagnostic test of reef health.

“By studying remote and marine protected areas, we were able to estimate how many fish would be on a coral reef without fishing, and how long it should take newly protected areas to recover,” says study lead author, Dr Aaron MacNeil from the Australian Institute of Marine Science.

“This allows us to gauge the impact of reef fisheries, and make informed management decisions that include timeframes for recovery,” Dr MacNeil says.

Coral reefs are home to thousands of species of fish and provide food and income for millions of people, particularly those in the developing world. Yet the scientists found that the vast majority of fished reefs they examined have lost more than half of their fish.

Marine reserves are the most effective way to recover fish populations, however, there are no benchmarks to determine if the protection is effective, or whether a reserve has recovered enough to be fished again.

The authors say it is also not feasible to lock away reef resources indefinitely when so many people depend on them for their livelihoods.

Millions of people depend on fish for food and their livelihoods. Image: Andrew Baird

To solve this problem, the team studied the fish biomass on coral reefs around the world and discovered that near-pristine reefs contain 1,000 kilos (a tonne) of fish per hectare. Using this figure as a benchmark, they found that 83 per cent of fished reefs have lost more than half of their fish biomass (volume of fish).

From their work the scientists were able to determine that once protected, previously fished reefs take about 35 years to recover, while heavily depleted reefs take almost 60 years.

Co-author, Dr Nick Graham from the ARC Centre of Excellence for Coral Reef Studies at James Cook University says it was encouraging to find that substantial biomass remained where some form of management was in place.

“Changes in fishing practices can result in a significant return of key fish species over time,” Dr Graham says.

“Restrictions on types of gears, species caught, or local customs, all ensured substantial recovery in fish feeding groups. However, only completely closed marine protected areas successfully returned large predatory fish to the ecosystem,” Dr Graham says.

“Fish play important roles in the overall functioning of coral reef ecosystems, for example in controlling seaweed and invertebrates. By linking fisheries to ecology, we can now uncover important ecosystem functions for a given level of fish biomass.”

Dr MacNeil says fisheries managers have the potential to arrest a key threat to coral reefs.

“Where previously we have been managing reef fisheries not really knowing how depleted fish stocks were, we now have a roadmap for recovery that tells us not only where we are with fish biomass, but where we might want to go, and how long it will take to get there” he says

Co-author, Dr Tim McClanahan, from the Wildlife Conservation Society in New York, says the findings will help fishers determine how much catch to take and how much to leave behind.

“The methods used in this study are simple enough that fishers and managers can take the weight and pulse of their reef and keep it in a healthy range that had not previously been defined,” Dr McClanahan says.

“By choosing to conserve resources, fishers and managers have the ability to plan for recovery and help reefs remain productive in the face of increasing stress from climate disturbances.”

~~~

 Paper

The paper, Recovery potential of the world’s coral reef fishes by M. Aaron MacNeil, Nicholas A.J. Graham, Joshua E. Cinner, Shaun K. Wilson, Ivor D. Williams, Joseph Maina, Steve Newman, Alan M. Friedlander, Stacy Jupiter. Nicholas V.C. Polunin, and Tim McClanahan is published in the journal Nature.

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14358.html

Contacts

Dr Aaron MacNeil, AIMS, +61 (0)437 409 019, a.macneil@aims.gov.au (AEDT)

Dr Nicholas Graham, Coral CoE, +61 (0)466 432 188, nick.graham@jcu.edu.au

Dr Tim McClanahan, WCS, +1 415 518 4604, tmcclanahan@wcs.org (EST)

Eleanor Gregory, Coral CoE communications, +61 (0) 428785 895, eleanor.gregory@jcu.edu.au

Researchers in Queensland have found that where baby corals choose to settle is influenced by ocean temperature and the presence of their symbiotic algae in the water.

Warmer than normal maximum temperatures are known to have a negative impact on the reproduction and survival of some corals. The researchers wanted to find out how a cooler climate, similar to that found south of the Great Barrier Reef, would affect coral larvae settlement.

“We were interested to see how temperature influenced the selection of where corals chose to settle,” says Dr Eugenia Sampayo from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at the University of Queensland.

“At colder than average ambient temperatures we found that the larvae settled on more exposed surfaces where they were more likely to be damaged or removed entirely by fish.”

Coral larvae actively search out a place to settle using a range of sensory cues. Once in place they can’t move, so a poor choice of location increases the risk of death.

As part of the experiment researchers exposed larvae from coral commonly found on the Great Barrier Reef, Acropora millepora, to several different temperatures; including normal temperatures for the Great Barrier Reef and cooler temperatures similar to those experienced south of the Great Barrier Reef.

Coral Spawning. Image: Natalia Winkler

Under normal conditions, the larvae prefer to settle on surfaces covered in crustose coralline algae, but the researchers found larvae in the cooler water were less likely to choose such a surface, reducing their chance of a successful settlement.

The researchers also examined the influence of dinoflagellates (Symbiodinium), microscopic single celled organisms that live inside coral tissue once it has settled. This so-called symbiotic relationship is essential to the survival of corals in tropical oceans.

“Perhaps the most surprising result is that the presence of these symbionts in the water also influenced whether the coral larvae settled on the algae encrusted surfaces or not,” says study lead author, Natalia Winkler from the Coral CoE.

“The fact that the symbionts can influence larval settlement without actually being inside the coral tissue highlights just how important the symbionts are for corals,” Ms Winkler says

Dr Sampayo adds the results suggest a link between crustose coralline algae and the symbionts.

“If symbionts cluster near favorable locations, the coral larvae kill two birds with one stone by finding a good spot to settle and a concentrated source of symbionts, which are normally sparse in the water,” Dr Sampayo says.

“We have discovered a previously unknown biological control over coral settlement, one that is likely to be influenced by warming oceans and that can change how corals select their life-long position on the reef.”

Paper

Symbiodinium identity alters the temperature-dependent settlement behaviour in Acropora millepora coral larvae before onset of symbiosis by Winkler NS, Pandolfi JM, Sampayo EM is published in the journal, Proceedings of the Royal Society London B. http://dx.doi.org/10.1098/rspb.2014.2260

Contacts

Dr Eugenia Sampayo, Coral CoE, +61 (0) 7 3365 2729, e.sampayo@uq.edu.au

Natalia Winkler, Coral CoE, natalia.s.winkler@gmail.com

Eleanor Gregory, Communications Manager, +61 (0) 428 785 895,

eleanor.gregory@jcu.edu.au

 

Coral reefs provide a range of benefits, such as food, opportunities for income and education, but not everyone has the same access to them, according to a new study conducted by the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

The researchers examined how people from 28 fishing communities in Madagascar, Kenya, Tanzania and Seychelles benefit from the marine environment.

For many years conservation in developing countries has been based on the assumption that improvements in ecosystem conditions, such as increasing coral reef fish biomass, will benefit the community as a whole.

But Dr Christina Hicks, a social scientist, says this is approach is too simplistic.

“Increased supply tends to benefit the elite, not the community as a whole,” Dr Hicks says.

“We need to look at the social and economic access mechanisms that would enable a wider group of people to benefit from reefs and then develop policies based on that information,” she says.

Study co-author Professor Josh Cinner from the Coral CoE says the focus on increasing the supply of benefits isn’t enough.

“We need to pay more attention to how that benefit is distributed and how it is accessed by different people within a community,” Professor Cinner says.

The researchers argue that policy makers need a more inclusive approach to managing coral reefs, which includes a focus on improving wellbeing.

“We tend to focus on economic growth because it is easy to measure, but this should be greatly expanded to include the way people can share in the benefits that flow from reefs,” Dr Hicks says.

Paper

Social, institutional, and knowledge mechanisms mediate diverse ecosystem service benefits from coral reefs by Christina C. Hicks and Joshua E. Cinner is published in the journal Proceedings of the National Academy of Sciences of the USA.

http://www.pnas.org/content/early/2014/11/26/1413473111.long

Contacts

Dr Christina Hicks, +61 (0) 466 437 490 christina.hicks@jcu.edu.au

Professor Joshua Cinner, +61 (0) 417 714 138, joshua.cinner@jcu.edu.au

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

Preserving an intact population of weed-eating fish may be vital to saving the world’s coral reefs from being engulfed by weed as human and climate impacts grow.

A new study by researchers at the ARC Centre of Excellence for Coral Reef Studies has found weed-eaters like parrotfish and surgeonfish can only keep coral reefs clear of weed up to a point. After the weeds reach a certain density, they take over entirely and the coral is lost.

Collecting weed: Seaweed on an inshore reef of the Great Barrier Reef

For some years researchers have pinned their hopes on the ability of weed-eating fish to keep the weeds at bay while the corals recover following a major setback like bleaching, a dump of sediment from the land, or a violent cyclone.

However the latest work by Dr Andrew Hoey and Professor David Bellwood at CoECRS and James Cook University shows that once the weeds reach a certain density, the fish no longer control them, and prefer to graze less weedy areas. “As a result, the whole system tips from being coral-dominated to weed-dominated,” Andrew says.

“And our work shows that it doesn’t take a very high density of the fleshy seaweeds like Sargassum to discourage the fish, a patch of weed the size of a back garden could be enough to trigger a change. The fishes show a clear preference for grazing more open areas.”

Coral reefs are in decline worldwide, with many of them – especially in the Asia-Pacific region – showing ‘phase shifts’ from being coral-dominated to degraded states dominated by large fleshy seaweeds.

“In countries where people harvest the weed-eating fishes with spearguns, nets and so on, like Fiji, we are seeing a fundamental change in the nature of reefs from coral to weeds,” Andrew says. “In Australia where there is much less harvesting of herbivorous fishes, the corals are in better shape and bounce back more readily from setbacks.”

The new insight into how well or poorly fish control weeds was gained by transplanting different densities of sargassum weed on a reef off Orpheus Island – and then using remote video cameras to record what the fish did.

“My wife and I must have watched hours and hours of video of fish feeding on weeds and counting the number of bites they took. It’s one of the less glamorous aspects of doing marine science,” he admits with a laugh.

In all they counted 28 species of fish taking 70,685 separate bites of weed and removing an average of 10 kilos of weed a day. In the more open areas this was enough to control the weed.

But Andrew also noticed the fish avoided the densely-weeded areas, perhaps for fear of predators lurking in the weed or because mature weeds are less palatable.

“This suggested to us there is a critical weed density, beyond which fish no longer control the weeds and they then take over the reef system. This in turn implies a need to keep the herbivore population as healthy as possible to avoid the reef reaching that tipping point.”

Fortunately, in Australia’s Great Barrier Reef Marine Park the harvesting of herbivorous fish is limited to a few recreational fishers. However Andy says it is his view that herbivorous fish ought to be carefully protected in order to give the Reef’s corals their best chance of making a rapid recovery from impacts like mass bleaching, the mud dumped by recent floods, and cyclones like Yasi.

Seaweed overgrowing a massive coral on an inshore reef of the Great Barrier Reef

“We should also bear in mind that this study was conducted in an area of the Great Barrier Reef Marine Park that has been protected from all commercial and recreational fishing for over 20 years and so is likely to have intact fish communities.

“How herbivores respond in areas of the world where they are still heavily fished may be absolutely critical to the survival of large areas of reef in Asia and the Pacific – and hence to the human communities who depend on them for food, tourism and other resources.”

The paper “Suppression of herbivory by macroalgal density: a critical feedback on coral reefs?” by Hoey A and Bellwood D, appears in the latest issue of Ecology Letters, (2011) 14: 267–273

More information:
Dr Andrew Hoey, CoECRS and JCU, +61 7 4781 5761 or +61 0458 174 583
Jenny Lappin, CoECRS, +61 7 4781 4222 or +61 417 741 638
Jim O’Brien, James Cook University Media Office, +61 7 4781 4822 or +61 0418 892449

CoECRS are proud sponsors of the 12th International Coral Reef Symposium, Cairns:  9-13 July 2012.

The fate of the world’s coral reefs may hang on a group of weed-eating fish, an Australian scientist has warned.

Worldwide, coral reefs are being smothered beneath a green tide of weed which is flourishing as humans pour nutrients into the oceans from erosion, agriculture, sewage and development.

But a major factor in the reefs’ decline may also be the uncontrolled slaughter and removal of parrot fish and surgeon fish, the ‘gardeners of the reef’, says Professor Dave Bellwood of the Australian Research Council Centre of Excellence for Coral Reef Studies and James Cook University.

“We are only just beginning to realize what a vital role these groups of fish play in keeping reefs clean, healthy and free of weed.

“Remove them, and you as good as remove the reef itself,” Prof. Bellwood says. “Without the fish to mow the weed, it soon takes over completely from the coral.”

Worldwide the larger herbivorous fish are now the targets of a mass plunder by fish trappers, spear fishermen and gill netting, as the highly-prized carnivores – like coral trout and snappers – are hunted out.

In Australia, the picture is less bleak, with traps illegal, no-fish zones and an ethos in spear-fishing clubs not to hunt herbivores – but the situation still needs watching closely, he cautions.

“People are generally unaware how essential these groups of fishes are to the upkeep and protection of the reef. And, as scientists, we still do not understand clearly which are the critical functional groups – the most important ones for preserving the health of the coral ecosystem.

“Australia faces the loss of many of the big weed-removers – the dugongs and green turtles. On reefs, the job is almost entirely down to the fishes. If we lost them too, it would spell tragedy.”

For instance, he says, some herbivores in turn depend on mangroves as nurseries for their young. The removal of mangroves may thus lead to loss of herbivores and, ultimately, to loss of coral.

Experiments have shown that the removal of grazing fishes from an area of reef leads to the coral becoming completely smothered by weed in a short time.

So far no-one in the world has yet succeeded in reversing the process when a coral reef turns to weed, but the scientists at the Coral Reef Centre remain optimistic.

“I’d say we simply don’t know enough about the role of the different species, and which ones will be most effective in ‘mowing’ a reef that has been engulfed by weed. That is what we are exploring now,” Prof. Bellwood says.

In the past 50 million years, coral reefs have shown extraordinary resilience, coping with massive swings in climate and ocean level.

“But somehow, it seems, they have built up a dependency on this group of weed-eating fish – and maybe on other groups that perform important functions such as the holothurians which sweep the seabed. It looks as if coral cannot survive for long without its constant gardeners.”

Professor Bellwood says that if the Centre’s research can identify the key species and work out a strategy to get them to remove the weed from an infested reef it would bring new hope for many of the world’s reefs which are now in dire condition.

More information:
Professor David Bellwood, CoECRS, +61 7 4781 4447, David.Bellwood@jcu.edu.au
Professor Terry Hughes, Director, ARC Centre of Excellence for Coral Reef Studies, +61 7 4781 4000
James Cook University Media Office,+61 7 4781 4586

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