Parts of Australia’s Great Barrier Reef show highest coral cover in 36 years

MELBOURNE/SYDNEY, Aug 4 (Reuters) – Two-thirds of Australia’s Great Barrier Reef showed the most coral cover in 36 years, but the reef remains vulnerable to increasingly frequent mass bleaching, a official long-term monitoring program. .

The recovery in the central and northern reaches of the UNESCO World Heritage-listed reef contrasted with the southern region, where there was a loss of coral cover due to outbreaks of crown-of-thorns starfish, the Australian Institute of Science said. Navy (AIMS). in your annual report.

“What we’re seeing is that the Great Barrier Reef remains a resilient system. It still maintains that ability to bounce back from disturbances,” AIMS monitoring program leader Mike Emslie told Reuters.

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“But what is worrying is that the frequency of these disturbance events is increasing, particularly massive coral bleaching events,” he said.

The report comes as UNESCO considers whether to list the Great Barrier Reef as “endangered”, following a visit by UNESCO experts in March. The meeting of the World Heritage Committee, where the fate of the reef was on the agenda, was due to be held in Russia in June, but was postponed.

In a key measure of reef health, AIMS defines hard coral cover of more than 30% as high value, based on its long-term studies of the reef.

In the northern region, average hard coral cover grew to 36% in 2022 from a low of 13% in 2017, while in the central region hard coral cover increased to 33% from a low of 12% in 2019, the highest levels recorded for both regions since the institute began monitoring the reef in 1985.

However, in the southern region, which generally has higher hard coral cover than the other two regions, cover fell to 34% in 2022 from 38% the previous year.

The recovery comes after the fourth mass bleaching in seven years and the first during a La NiƱa event, which typically brings cooler temperatures. Although extensive, the institute said, bleaching in 2020 and 2022 was not as damaging as it was in 2016 and 2017.

On the downside, the growth in cover has been driven by Acropora corals, which AIMS says are particularly vulnerable to damage from waves, heat stress and crown-of-thorns starfish.

“We’re really in uncharted waters when it comes to the effects of bleaching and what it means to move forward. But to this day, it’s still a fantastic place,” Emslie said.

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Reporting by Sonali Paul in Melbourne and James Redmayne in Sydney; Edited by Stephen Coates

Our standards: the Thomson Reuters Trust Principles.

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