Coral reproduction on the Great Barrier Reef falls 89% after repeated bleaching


Morgan Pratchett, James Cook University

The severe and repeated bleaching of the Great Barrier Reef has not only damaged corals, it has reduced the reef’s ability to recover.

Our research, published today in Nature, found far fewer baby corals are being produced than are needed to replace the large number of adult corals that have died. The rate at which baby corals are settling on the Great Barrier Reef has fallen by nearly 90% since 2016.

While coral does not always die after bleaching, repeated bleaching has killed large numbers of coral. This new research has negative implications for the Reef’s capacity to recover from high ocean temperatures.

How coral recovers

Most corals reproduce by “spawning”: releasing thousands of tight, buoyant bundles with remarkable synchronisation. The bundles burst when they hit the ocean surface, releasing eggs and/or sperm. Fertilised eggs develop into larvae as they are moved about by ocean currents. The larvae settle in new places, forming entirely new coral colonies. This coral “recruitment” is essential to reef recovery.




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The research team, led by my colleague Terry Hughes from the ARC Centre of Excellence for Coral Reef Studies, measured rates of coral recruitment by attaching small clay tiles to the reef just before the predicted mass spawning each year. These settlement panels represent a standardised habitat that allows for improved detection of the coral recruits, which are just 1-2mm in size.

Almost 1,000 tiles were deployed across 17 widely separated reefs after the recent mass bleaching, in late 2016 and 2017. After eight weeks they were collected and carefully inspected under a microscope to count the number of newly settled coral recruits. Resulting estimates of coral recruitment were compared to recruitment rates recorded over two decades prior to the recent bleaching.

Australian Academy of Science.

Rates of coral recruitment recorded in the aftermath of the recent coral bleaching were just 11% of levels recorded during the preceding decades. Whereas there were more than 40 coral recruits per tile before the bleaching, there was an average of just five coral recruits per tile in the past couple of years.




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Tropical marine conservation needs to change as coral reefs decline


Reef resilience

The Great Barrier Reef (GBR) is the world’s largest reef system. The large overall size and high number of distinct reefs provides a buffer against most major disturbances. Even if large tracts of the GBR are disturbed, there is a good chance at least some areas will have healthy stocks of adult corals, representing a source of new larvae to enable replenishment and recovery.

Larvae produced by spawning corals on one reef may settle on other nearby reefs to effectively replace corals lost to localised disturbances.

It is reassuring there is at least some new coral recruitment in the aftermath of severe bleaching and mass mortality of adult corals on the GBR. However, the substantial and widespread reduction of regrowth indicates the magnitude of the disturbance caused by recent heatwaves.

Declines in rates of coral recruitment were greatest in the northern parts of the GBR. This is where bleaching was most pronounced in 2016 and 2017, and there was the greatest loss of adult corals. There were much more moderate declines in coral recruitment in the southern GBR, reflecting generally higher abundance of adults corals in these areas. However, prevailing southerly currents (and the large distances involved) make it very unlikely coral larvae from southern parts of the Reef will drift naturally to the hardest-hit northern areas.

It is hard to say how long it will take for coral assemblages to recover from the recent mass bleaching. What is certain is low levels of coral recruitment will constrain coral recovery and greatly increase the recovery time. Any further large-scale developments with also greatly reduce coral cover and impede recovery.




Read more:
The 2016 Great Barrier Reef heatwave caused widespread changes to fish populations


Reducing carbon emissions

This study further highlights the vulnerability of coral reefs to sustained and ongoing global warming. Not only do adult corals bleach and die when exposed to elevated temperatures, this prevents new coral recruitment and undermines ecosystem resilience.

The only way to effectively redress global warming is to immediately and substantially reduce global carbon emissions. This requires that all countries, including Australia, renew and strengthen their commitments to the Paris Agreement on climate change.

While further management is required to minimise more direct human pressure on coral reefs – such as sediment run-off and pollution – all these efforts will be futile if we do not address global climate change.The Conversation

Morgan Pratchett, Professor, ARC Centre of Excellence for Coral Reef Studies, James Cook University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Morrison government approves next step towards Adani coal mine


Michelle Grattan, University of Canberra

The Morrison government has ticked off on the groundwater management plan for the proposed Adani coal mine, an important but not a final step for the central Queensland project receiving the go-ahead.

The decision, taken by Environment Minister Melissa Price, comes after intense pressure from Queensland Liberal National Party members, including a threat by senator James McGrath to publicly call for Price’s resignation if she failed to treat the Adani project fairly.




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View from The Hill: It’s the internal agitators who are bugging Scott Morrison on Adani


But the Adani decision will not help Liberals fighting seats in the south, with strong anti-Adani campaigns in some key electorates.

Price said in a statement on Tuesday: “CSIRO and Geoscience Australia have independently assessed the groundwater management plans for the Carmichael Coal Mine and Rail Infrastructure project”, and both had confirmed the revised plans met strict scientific requirements.

“Following this independent assessment and the Department of Environment and Energy’s recommendation for approval, I have accepted the scientific advice and therefore approved the groundwater management plans” for the mine and rail infrastructure under Environmental Protection and Biodiversity Conservation Act.

She said the decision did not amount to final approval for the project.

It needed further approvals from the Queensland government before constructing could commence. So far only 16 of 25 environmental plans have been finalised or approved by the Commonwealth and Queensland with nine more to be finalised.

The project “must meet further stringent conditions of approval from the Commonwealth before it can begin producing coal,” Price said.

It had “been subject to the most rigorous approval process of any mining project in Australia,” she said.

Resources Minister Matt Canavan, a Queenslander who has been agitating for progress on the mine, said: “I welcome these further approvals. Now we need the state Labor government to stop dragging their heels and get on with the job of creating these jobs.”

Bill Shorten – who, like the government, has been caught between the conflicting imperatives of campaigning in central Queensland and in southern Australia on this issue – said the Queensland government now had to go through its processes.

Labor would “adhere to the law” and be “guided by the science,” he said. “We are not interested in sovereign risk.”

Referring to the pressure within the Coalition, Shorten said: “Trying to pressure people now creates a cloud over a process that didn’t need to be there but for the government’s division in their own ranks”.

Labor’s climate spokesman Mark Butler said that people across Australia would be asking themselves “how can you have any confidence that this decision was made on the merits of the case rather than because of the internal division and chaos in this government?”.




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Grattan on Friday: Scott Morrison struggles to straddle the south-north divide


The Australian Conservation Foundation’s Christian Slattery said “Coal-loving Coalition MPs appear to have strongarmed the Environment Minister into granting Adani access to Queensland’s precious groundwater on the eve of the election”.

Slattery said that if Price had been pressured to rush through the approval ahead of the election, the decision might be open to legal challenge.

He said the Queensland government was yet to sign off on Adani’s Black-Throated Finch Management Plan and Groundwater Dependent Ecosystem Management Plan.

“And, importantly, Adani does not have federal approval for the proposed above-ground water infrastructure it requires to support its proposed thirsty coal mine,” Slattery said.

GetUp said there would be a backlash against the decision. “The Coalition can expect to lose a swathe of seats around Australia for their capitulation to a single coal company at the expense of the community.

“A storm of local groups are already hard at work in Kooyong and Flinders, and now GetUp is going to make an extra 100,000 calls into Flinders and 80,000 calls into Kooyong. This could cost Josh Frydenberg and Greg Hunt their jobs”.

Tasmanian independent MP Andrew Wilkie said: “This decision is environmental vandalism at its most extreme, facilitated by the most useless environment minister the country’s ever seen”.

In a statement Adani complained about its treatment from the Queensland government.

“Throughout the past 18 months, the Federal Department provided us with certainty of process and timing, including the steps involved in the independent review by CSIRO and Geoscience Australia experts.

In contrast, the Queensland government has continued to shift the goal posts when it comes to finalising the outstanding environmental management plans for the mine and is standing in the way of thousands of jobs for Queenslanders.

It’s time the Queensland government gave us a fair go and stopped shifting the goal posts so we can get on with delivering these jobs.”The Conversation

Michelle Grattan, Professorial Fellow, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Townsville floods show cities that don’t adapt to risks face disaster


Cecilia Bischeri, Griffith University

A flood-ravaged Townsville has captured public attention, highlighting the vulnerability of many of our cities to flooding. The extraordinary amount of rain is just one aspect of the disaster in Queensland’s third-biggest city. The flooding, increasing urban density, the management of the Ross River Dam, and the difficulties of dealing with byzantine insurance regulations have left the community with many questions about their future.

These questions won’t be resolved until we enhance the resilience of cities and communities against flooding. Adaptation needs to become an integral part of living with the extremes of the Australian environment. I discuss how to design and create resilient urban landscapes later in this article.




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Queensland’s floods are so huge the only way to track them is from space


Flood risk and insurance

Another issue that affects many households and businesses is the relationship between insurance claims and 1-in-100-year flood event overlay maps. Projected rises in flood risks under climate change have led to concerns that parts of Townsville and other cities will become “uninsurable” should the costs of cover become prohibitive for property owners.

Council flood data used for urban planning and land-use strategies is also used by insurers to assess the flood risk to individual properties. Insurers then price the risk accordingly.




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Lessons in resilience: what city planners can learn from Hobart’s floods


However, in extraordinary circumstances, when the flooded land is actually larger than the area marked by the flood overlay map, complications emerge. In fact, that part of the community living outside the map’s boundaries is considered flood-free. Thus, those pockets of the community may have chosen not to have flood insurance and not have emergency plans, which leaves them even worse off after floods. This is happening in Townsville.

Yet this is nothing new. Many people experienced very similar circumstances in 2011. Flood waters covered as much land as Germany and France combined. Several communities were left on their knees.

Notwithstanding the prompt and vast response of the federal government and Queensland’s state authorities, a few years later Townsville is going through something alarmingly similar.

Adaptation to create resilient cities

To find a solution, we need to rethink how to implement the Queensland Emergency Risk Management Framework. That is no easy task. However, it starts with shifting the perspective on what is considered a risk – in this case, a flooding event.

Floods, per se, are not a natural disaster. Floods are part of the natural context of Queensland as can be seen below, for instance, in the Channel Country.

Floods are part of the Australian landscape. Here trees mark the seasonal riverbeds in the Queensland outback between Cloncurry and Mount Isa.
Cecilia Bischeri, Author provided

The concept of adaptation as a built-in requirement of living in this environment then becomes pivotal. In designing and developing future-ready cities, we must aim to build resilient communities.

This is the ambitious project I am working on. It involves different figures and expertise with a shared vision and the support of government administrations that are willing to invest in a future beyond their elected term of office.

Ideas for Gold Coast Resilientscape

I live and work in the City of Gold Coast. Water is a fundamental part of the city’s character and beauty. In addition to the ocean, a complex system of waterways shapes a unique urban environment. However, this also exposes the city to a series of challenges, including flooding.

Last September, an updated flood overlay map was made available to the community. The map takes into account the projections of a 0.8 metre increase in the sea level and 10% increases in storm tide intensity and rainfall intensity.

These factors are reflected in the 1-in-100-year flood overlay. It shows undoubtedly that the boundaries between land and water are changeable.

Building walls between the city and water as the primary flood protection strategy is not a solution. A rigid border can actually intensify the catastrophe. New Orleans and the levee failures during the passage of Hurricane Katrina in 2005 provide a stark illustration of this.

Instead, what would happen and what would our cities look like if we designed green and public infrastructures that embody flooding as part of the natural context of our cities and territory?




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Design for flooding: how cities can make room for water


The current project, titled RESILIENTSCAPE: A Landscape for Gold Coast Urban Resilience, considers the role of architecture in enhancing the resilience of cities and communities against flooding. The proposal, in a nutshell, explores the possibilities that urban landscape design and implementation provide for resilience.

RESILIENTSCAPE focuses on the Nerang River catchment and the Gold Coast Regional Botanic Gardens, in the suburb of Benowa. The river and gardens were adopted as a case study for a broader strategy that aims to promote architectural solutions for a resilient City of Gold Coast. The project investigates the possibility of using existing green pockets along the Nerang River to store and retain excess water during floods.

Gold Coast Regional Botanic Gardens is one of the green areas along the Nerang River that could be used to store and retain flood water.
Batsv/Wikimedia Commons, CC BY-SA

These green spaces, however, will not just serve as “water tanks”. If mindfully planned, the green spaces can double up as public parks and facilities. This would enrich the community’s social realm and maximise their use and return on investment.

The design of a landscape responsive to flooding can, by improving local urban resilience, dramatically change the impact of these events.

The goal of creating urban areas that are adaptive to an impermanent water landscape is the main driver of the project. New Orleans after Hurricane Katrina and New York after Sandy are investing heavily in this direction and promoting international design competitions and community participation to mould a more resilient future. Queensland, what are we waiting for?




Read more:
Floods don’t occur randomly, so why do we still plan as if they do?



This article has been updated to clarify the use of flood data by insurers in assessing risk and the cost of cover.The Conversation

Cecilia Bischeri, Lecturer in Architecture, Griffith University

This article is republished from The Conversation under a Creative Commons license. Read the original article.