A groundbreaking study of hundreds of Australian islands has exposed the threats posed to K’gari (Fraser Island) and prompted a grim warning from experts.
They say that without improved management, ever-increasing tourist numbers – including the crowds expected during the Brisbane Olympics in 2032 – are putting the island’s World Heritage status at risk.
The University of Queensland Biodiversity Research Group study found that of 567 islands with freshwater habitats, 197 contained 102 frog species, amounting to almost half of all known Australian frog species.
Ninety-five freshwater fish species were found, 11 of which were vulnerable or endangered.
Samuel Ho started investigating the intersection of freshwater habitats and islands as an honours student UQ. (Supplied: University of Queensland)
Researcher Sam Ho said he was shocked by the number of frog species and hoped the information would be used to conserve those at risk of extinction on the mainland.
Biodiversity Research Group head Professor Salit Kark said the role of islands as refuges for endangered species meant they had often been “extinction hubs” where the last remaining individuals of a species had been lost, including the King Island emu and the Norfolk Island kaka.
The results  of the research have been published in Diversity and Distributions journal.
An artist’s impression of Sea Elephant Bay on King Island, circa 1802. Emus were hunted to extinction within a decade of settlement. (Supplied: Julian Hume)
‘Flagship’ island swarmed
The study found K’gari, the world’s largest sand island, had the most frog and freshwater species of all Australian islands.
Professor Kark said the rich biodiversity on K’gari highlighted the value of its World Heritage status.
“I think it should be really one of the flagship islands that we’re further studying and investing in,” she said.
Mr Ho and his colleagues did a year-long search of scientific databases, journals and government reports, boosted by the Atlas of Living Australia, Australia’s largest biodiversity database fed by citizen-science platforms such as iNaturalist.
The data collected by growing numbers of citizen scientists was a boon for the researchers but Professor Kark said there was a “trade-off” with the impacts of the increasing numbers of visitors.
The graceful tree frog is found on K’gari. (Supplied: Samuel Ho)
“I think it’s really that balance that needs to be thought about quite carefully, and we must have more data both on the [visitor] impacts but also for native and introduced species,” she said.
A 10-year strategic plan released this year by the K’gari World Heritage Advisory Committee said the island received up to one million visitors annually.
Suggested options for managing the surging visitor numbers include charging a fee for each individual visitor and capping access to popular sites during peak periods.
“Almost certainly, with over-visitation already occurring at popular sites at peak periods, without further consideration and management intervention, visitation will threaten K’gari’s [World Heritage value],” the report said.
The ornate rainbow fish is a freshwater species found on K’gari. (Supplied: Samuel Ho)
‘The future is quite bleak’
Grant Wardell-Johnson, an associate professor in biodiversity and forest ecology at Curtin University, said the UQ team had compiled “a very comprehensive and useful database”.
Dr Wardell-Johnson, who was not involved in the study, said the data highlighted the urgency for changes to the current approaches to visitor management on K’gari.
“There’s certainly very little in the way of managing numbers of people and what they do on the island, and certainly the future is quite bleak in terms of biodiversity conservation,” he said.
A K’gari World Heritage Advisory Committee says controls are needed to manage visitors to K’gari ahead of the 2032 Olympics. (ABC Radio Brisbane: Lucy Stone)
Because K’gari was primarily managed by Queensland agencies, Dr Wardell-Johnson said its World Heritage status should be protected by similar state laws to those in place for the Wet Tropics and Great Barrier Reef.
A spokesperson for the Department of the Environment, Tourism, Science and Innovation said K’gari’s World Heritage value was protected by federal laws.
Neither the DETSI spokesperson nor Environment Minister Andrew Powell responded to questions about whether visitor caps were being considered for K’gari.