The coral cover of Australia’s Great Barrier Reef, a World Heritage Site, has halved over the past 27 years due to cyclones, poisonous starfish and bleaching linked to climate change, a new study has found.
Researchers at the Australian Institute of Marine Science in Townsville have found the loss of coral was caused mainly due to cyclones and crown-of-thorns starfish.
Coral bleaching was also to blame, the report was quoted by Australia’s ABC news as saying.
The study has been published in Proceedings of the National Academy of Sciences.
The Great Barrier Reef is the world’s largest coral reef system.
The report has warned the rate at which the reef was declining continued, its coral cover could halve again by 2022 and it may lose the biodiversity for which it was listed as a World Heritage Area in 1981.
The study also argued that stopping the progress of the crown-of-thorns starfish was crucial to the recovery of the 3,000 km-long reef.
One of the researcher John Gunn said the future of the ecosystem could be under threat if the loss of coral is not stopped.
“Accumulative impacts of storms and crown-of-thorns and two bleaching events have had a devastating effect over the last three decades,” Gunn said, adding, “we're very concerned that this is a bit of a crossroads for the reef and this data are very authoritative.”
“I can’t pretend that if we had this type of impact continuing and we had some of the possible impact of climate change in the future that the Great Barrier Reef really is at threat,” Gunn said.
Gunn, chief executive of the institute in Townsville, said damage to the reef was patchy, with some areas affected more than others.
“There are parts of the reef that are still pretty much as we’d like the whole of the reef to be, and they give us some hope that that’s what we could achieve with the whole of it,” Gunn said.
“These are areas north of Cooktown and they’re pretty healthy reefs, in fact they’re beautiful. It’s the areas that really have these cumulative impacts, the three factors that we take account of in the study that have really come under sort of major pressure,” he said.
“But even there, there are reefs that are still very, very lovely to visit,” he added.