While foxes – which also feed on marsupials – can be controlled by spreading poisoned bait, cats prefer to eat prey they kill. Eradicating foxes, though, also removed one species capable of suppressing cat numbers, he said.

While the native animals find ways to survive the fires, they now tend to get picked off by cats moving on the fringes of the blazes. “Cats really like these big fires late in the season,” Professor Johnson said.

Indigenous burning practices tended to be early in the season, leaving a mosaic of vegetation that native animals find refuge in. Savannah fires, coming every two or three years, now tend to be late in the season and destroy more of the landscape.

ACEAS data monitored 600,000 native animals across the continent and identified fire-management practices combined with the infestation of cats as the likely trigger for the dive in northern animals.

About 100 marsupial species are at risk of extinction across the continent, adding to the urgency of understanding and reversing the sudden dive in northern species numbers. At least six northern marsupials may soon survive only in the wild on offshore islands removed from the cat menace, Professor Johnson said.

The impact of fires and invasive species in southern forests, such as in NSW and Victoria, was more complex, he said. Deer and foxes, though, appear to benefit from fires.

Government efforts to meet hazard-reduction goals may have impacts on the biodiversity with little benefit for the wider community in terms of cutting fuel loads close to the populace.

Victoria, for instance, has a goal of burning 5 per cent of the public estate each year.

“What that tends to mean is the places that are easiest to burn tend to get burnt more frequently to get up to the 5 per cent target, and there may not be much benefit in that,” he said. “It tends to simplify the vegetation and makes it easier for feral predators such as cats to come in and hunt.