Feral cats are savaging native reptiles in Kakadu National Park, according to a new study which estimates there are 3300 of the killing machines in the world heritage listed area.
For two years, researchers from the Northern Australia Environmental Resources Hub have been trialling two predator-proof mesh enclosures in the park near Kapalga, each one measuring 64 hectares, or 50 football fields.
They found that within the enclosures, the number of reptiles doubled when cats were taken out of the equation, said ecologist Danielle Stokeld from the NT Department of Land Resource Management.
“It’s the first time we’ve been able to demonstrate it up here in northern Australia,” she told AAP on Thursday.
She said the finding was a positive demonstration that native species could bounce back if feral cats were managed, but “the challenge of course is going to be in controlling cats, not an easy animal to study, let alone an easy animal to try and manage”.
Feral cats are the single biggest threat to Australian mammals and threatened species, with up to 20 million across Australia, killing up to 75 million native animals daily.
In Kakadu, researchers used motion detection cameras and cage traps to monitor native animals in the fenced and unfenced sites, and also studied cat droppings to work out which creatures they were eating.
With the cameras, they began building an estimate of the cat population in the park, finding that there was one cat per every 5 square kilometres at Kapalga, or an estimated 3300 across Kakadu.
“Over time, if we can try and get density estimates for different types of habitat it helps land managers get a better idea to where they should best be applying their efforts to try and control cats,” Ms Stokeld said.
But cats are only part of the problem of declining native fauna, said Graeme Gillespie, NT government Director of Terrestrial Ecosystems.
“Inappropriate fire regimes, combined with the impacts of introduced herbivores, such as feral pigs and buffalo, are having a significant impact on the habitats in which our natives take refuge,” he said in a statement.