Largest Ever Study Unlocks Global Solutions to Save Coral Communities

The survey of over 2500 reefs identified where and how to
save coral reef communities in the Indo-Pacific, outlining three
viable strategies that can urgently be enacted to help save coral reefs that
are threatened by climate change and human impacts.

The researchers found an unexpected
resilience among the coral communities. In particular, even after the
damage caused by severe heat stress during the 2014-17 El Niño event, the
authors identified nearly 450 reefs in 22 countries across the Indo-Pacific
that survived in climate “cool spots”. The finding means that urgent local
action to protect the coral communities must be aligned with global measures to
fight climate change.

Read the full story below from Macquarie University Science News:

“Being able to allocate spatially
explicit strategies to save reefs is a big leap in informing actionable
policies,” says Dr Joseph Maina, senior lecturer in spatial information science
at Macquarie University in New South Wales and a co-author of the study.

He adds that agricultural activity
on land showed up as a strong influence of reef health – revealing a target for
damage control.

“We now
need to determine key thresholds and specific actions that can be taken on land
to reduce pollution and counter land-based impacts on coral reefs. This will
give them a better chance of surviving climate change.”

Further
Australian input into the study came from scientists based at James Cook University, the
Australian Institute of Marine Science, the ARC Centre of
Excellence for Coral Reef Studies and the Sydney Institute of Marine
Science.

The survey, which was led by the US
Wildlife Conservation Society (WCS), constitutes the largest study of its kind
ever conducted. It identified where and how to save coral reef communities in
the Indo-Pacific. The study outlines three viable strategies that can urgently
be enacted to help save coral reefs that are threatened by climate change and
human impacts.

The findings revealed that the
majority of reefs had functioning coral communities, by assessing the living
cover of architecturally complex species that give reefs their distinctive
structure.

The landmark publication presents a
conservation framework of three management strategies – dubbed protect,
recover and transform – to safeguard reef ecologies and
ecosystem services into the future.

“The good news is that functioning
coral reefs still exist, and our study shows that it is not too late to save
them,” says Dr Emily Darling, lead author of the study and WCS Conservation
Scientist and leader of the organisation’s global coral reef monitoring
program.

“Safeguarding coral reefs into the
future means protecting the world’s last functioning reefs and recovering reefs
impacted by climate change. But realistically – on severely degraded reefs –
coastal societies will need to find new livelihoods for the future.”

Good news on the future of corals
has become rare in the twenty-first century, because increasing carbon
emissions and human impacts of overfishing, pollution and unsustainable
development have led to predictions of a bleak future for tropical reefs and
the millions of people who depend on them. The Indo-Pacific in particular, a
hotspot of coral reef biodiversity, has been devastated by periods of severe
heat stress and mass coral bleaching events in 1983, 1998, 2005, 2010, and most
recently in the world’s longest, largest and most intense bleaching event in
2014-2017.

The study also identifies the
minimum requirements to save functioning reefs. This required evaluating the
impacts of 20 environmental, climatic, and human-caused stressors on
reef-building corals. The authors found that higher abundances of
framework corals, the species that build the backbone of coral reefs, occurred
on reefs with fewer climate shocks and longer recovery windows. Higher coral
abundances were also found farther from coastal populations and their
associated markets and agricultural impacts.

The authors’ findings helped to
formulate the three strategic choices of management for the reefs.

Protect: 17 per cent of coral reefs in the study’s dataset had
functioning coral reefs and occurred in a climate ‘cool spot’ during the
2014-2017 El Niño. The reefs are found in 22 countries from East Africa to
South East Asia, the Coral Triangle, and the Pacific. These findings call for
an international network of coral reef conservation to save the world’s last
functioning coral reefs.

Recover: The second strategy is to promote rapid coral recovery where
reefs (54 percent of those examined in the study) were previously functioning
but have been recently impacted by the 2014-2017 coral bleaching event.

Transform: The third strategy recognizes that some
coastal societies will need to transform away from dependence on reefs that are
no longer functioning (28 percent of the reefs analysed fell into this
category).

The study’s findings stress that
strategic local management can play a role in helping protect corals through
tools such as marine protected areas or other management restrictions that
reduce threats and keep coral reefs above functional thresholds. However,
the authors noted that local management can complement but not replace the need
for worldwide efforts to limit carbon emissions.

“Saving reefs will require
combining local and global efforts, such as reducing local dependence on reef
fish to maintain a reef’s important functions while also reducing carbon
emissions to keep warming below 1.5 degrees Celsius,” says Dr Tim McClanahan,
WCS Senior Conservation Zoologist and co-author of the study.

The paper is available here: https://www.nature.com/articles/s41559-019-0953-8