Lord Howe Island's unique animal and plant life have been showing signs of a resurgence, thanks to a rodent eradication program launched in 2019.
Experts in snail biology surveyed 200 different sites across the island — located about 600 kilometres off the coast of New South Wales — and discovered four species of snail previously thought to be extinct.
Lorde Howe Island Board Environment World Heritage manager Hank Bower said it was clear evidence that the program was having a positive effect.
"Since the rodent program, those snail numbers have increased," he said.
"It's indicative that without the pressure from rodents, that species can return."
Scientists from the Australian Museum and the NSW government's Saving our Species program were involved in the painstaking process of finding the snails.
"They're tiny little things that live in very remote areas," Mr Bower said.
"They have to sift through the leaf litter, among the leeches in the rain."
A long process of discovery
NSW Minister for the Environment David Griffin said scientists dedicated hundreds of hours to the task before observing the species for the first time in 20 years.
"It's a landmark moment for conservation in NSW," he said.
It followed a program launched in 2019 by scientists and conservation groups to eliminate the island's extensive rodent population — largely considered responsible for the destruction of native flora and fauna.
"Historically, the island just baited to control rodents, to suppress them," Mr Bower said.
"We developed a program based on world's best practice where they would eliminate every rat and mouse from the island in one operation."
Other species rebounding
It has also led to a near-quadrupling in numbers for the Lord Howe Island woodhen population, a species that holds a special place in the hearts of islanders.
A March survey counted nearly 800 woodhens — up from about 200 in 2019.
It was a significant improvement from the 1970s when the bird population was believed to have fallen as low as 22.
"We're seeing a return with all species — seabirds, plants, insects, snails," Mr Bower said.
"We're seeing things we've never seen before."
Mr Griffin said the resurgence was a source of pride for those working on the island.
"That work has enabled us to get rid of more than 300,000 rodents," he said.
"As a result of that, we're starting to see a turning back of the tide and reversal in the decline of biodiversity on Lord Howe Island."
A weedy side effect
The next phase of conservation would involve controlling the island's weeds, which were also rebounding as a result of the rodent eradication program.
Mr Bower said it would require careful management going forward, to continue to support a recovery in biodiversity.
"It's really important that from here on into the future, we keep the pressure on the weed program, to make sure that program delivers the same results," he said.
