A giant, fluorescent pink slug’s comeback on Mount Kaputar has been mapped by eager citizen scientists.
The kaputar slug grows up to 20cm long – outstripping the average human hand – and 6cm wide. The only place it exists in the entire world is on an extinct volcano in NSW’s Mount Kaputar national park.
In 2019 the alpine area was hit by catastrophic bushfires with an estimated 90% of the population killed.
But in 2020, 60 survivors were spotted.
Since then, NSW National Parks and Wildlife Service has run the Slug Sleuth app, so park visitors can report sightings – usually after rainfall, and on cool, misty mornings. To date there have been about 850 reports, including some with dozens of slugs.
People can upload pictures and information about how many they saw, and where and when so experts can determine things such as its habitat preferences, and the effects of climate change on the population.
NPWS threatened species project officer, Adam Fawcett, said a lot of his threatened species projects were imperilled by the fires, but he was more optimistic than some about the slugs because it’s a fire-prone landscape that species have adapted to.
He said he was about to do the first ever survey of the slug when the fires hit.
“That fire was pretty bad,” he said. “We ended up with a large area of the summit burnt. Some areas were saved; some had had hazard reduction burns.
“But even though that fire ripped through there, really hot, the slugs came out after good rain in good numbers.
“We saw a mass breeding event, and because of La Niña the breeding continued.”
He said thanks to the app they’ve seen how the slug has recovered, and would be able to spot trends over time.
He carries out surveys of specific areas to measure the density of slugs, adding to the knowledge he gains from the app.
“In two sites, we’ve been getting about 200-odd slugs every time,” he sid.
“I get really excited, I go crazy taking pictures… I love when you see them doing something different … you just don’t know where to look.
“It’s pretty impressive.”
Fawcett said he was also able to compare the burnt and unburnt zones, and found that in the burnt areas the slugs had recovered to about the same levels as those in the unburnt areas.
It’s not entirely clear how they survived, but the prevailing theory is that they went deep into rock crevasses or far enough underground that they were protected from the heat.
The slug belongs to the Triboniophorus genus, which includes the red triangle slug, Australia’s biggest land slug.
The park is also home to 11 threatened snail species, including the kaputar winged snail, the nandewar pinwheel snail, and the nandewar carnivorous snail.
