Australia’s Great Barrier Reef burst back to life in remarkable fashion after being damaged by warmer waters, a new study has revealed.
The World Heritage site currently boasts its largest coral cover in decades. However, experts warned that the regrowth consisted largely of a common, fast-growing but weak genus known as acropora that could easily be lost.
Acropora is known for its branching colonies that resemble deer antlers and can grow in thickets covering large areas in a variety of colors.
It also plays a key role in reef building, providing a large percentage of the calcium carbonate structure, and is linked to the popular imagination of the Great Barrier Reef, which is often depicted on postcards.
However, it is particularly vulnerable to storms and crown-of-thorns starfish, which feed on coral and often grow in ‘boom and bust’ cycles.
The reef, which stretches almost 1,500 miles along the Queensland coast, has been badly affected by climate change in recent years and has suffered a series of “mass bleaching” events, where stressed corals turn white.
However, scientists revealed that the northern and central parts of the reef now have the highest amount of coral cover since monitoring began 36 years ago.
A question mark remains over the exact cause of the reef’s sudden recovery, suggesting that the ecosystem has much greater resilience and ability to bounce back than previously understood.
It may have been helped by a relatively quiet period in terms of cyclones and crown-of-thorns starfish, meaning that progress could be undone by further disturbances.
Dr Mike Emslie, research program manager from the Australian Institute of Marine Science, said the results were “good news” but there were still major concerns about the reef’s health.
Prof Terry Hughes, a marine scientist, said that replacing the large, old, slow-growing corals that had previously defined the reef was probably no longer possible, adding: “Instead, we are seeing partial reassembly of fast-growing, weedy corals before the next disturbance .”
Dr Paul Hardisty, chief executive of the Australian Institute of Marine Science, said “These latest results show that the reef can still recover from periods without intense disturbance.”
He also warned that the increased frequency of mass coral bleaching caused by climate change was “uncharted territory” for the reef, and that a bleaching earlier this year was the first to occur during a La Nina weather pattern.
Dr Maxine Newlands, a political scientist from James Cook University in Queensland, said the reef’s survival depended on a delicate balancing act.
“Politicians and decision-makers cannot see this as a sign of a recovered reef, but as an indicator that more needs to be done,” she insisted.
The Great Barrier Reef is one of the world’s most spectacular marine environments and attracted thousands of tourists a year in pre-pandemic times.
It created an estimated 64,000 jobs and generated almost £3.5 billion a year for the Australian economy.
The reef has been a UNESCO World Heritage Site since 1981 due to its scientific importance as one of the most diverse ecosystems on the planet.
However, officials from Unesco’s World Heritage Committee, which inspected the reef earlier this year, have accused Australian authorities of not doing enough to protect it.
There are fears it could be listed as “at risk”, which would reflect poorly on Australia’s environmental credentials and damage the image of one of the country’s main tourist attractions.