How destructive are invasive species?

How big are Australia’s problems with non-indigenous species like feral cats and cane toads, and can something be done about it?

“This is Australia’s sliding doors moment – a tale of two very different futures rests in our control.”

So warns a new report on Australia’s path towards a pest and weed-free future, published by CSIRO and The Centre For Invasive Species Solutions. The report, entitled ‘Fighting plagues and predators’, describes what it calls “a disaster unfolding in our backyards and on our doorsteps. From feral cats to toxic toads, choking weeds, deadly fungi and armies of ants, Australia is in the grip of an unprecedented attack on our native wildlife, environment and way of life.”

The report highlights the “worst of a bad bunch” with some grim statistics.

European rabbits infest two-thirds of Australia, and are the single biggest menace to threatened native species, it says, also costing an average $216 million a year in lost farm productivity.

Feral cats number from 2.1 million to 6.3 million depending on environmental conditions, and kill more than 456 million native mammals, 272 million birds, 92 million frogs, and 446 million reptiles each year.

Cane toads have invaded more than 1m square kilometres of Australia and are advancing up to 60km a year in Western Australia. They are fatally toxic to many native predators, including northern quolls and goannas.

Also on the blacklist are European carp, red imported fire ants and feral pigs. But it not just the fauna: plants like lantana, African grasses and prickly acacia also threaten native species. Blackberry infests nearly nine million hectares of land in Australia, providing fuel for bush fires and shelter for rabbits and foxes.

Taken together, their damage to native species is worse than habitat destruction and climate change, says the report, which promotes urgent actions including new and improved biocontrols, monitoring by drones and automated sensor networks, and protecting Australia’s reputation for biosecurity and safe exports. It also highlights the role of Aboriginal and Torres Strait Islander people as Australia’s greatest land custodians, and the benefit of their knowledge in the management of invasive species.

Everyone has a role to play, says the report, encouraging simple steps like being a responsible pet owner, and especially keeping cats inside and dogs on a lead when walking. Travel safely, and don’t bring restricted items into the country. Grow natives in the garden, and report pest species and animal locations using the FeralScan app. The Centre for Invasive Species Solutions also has a podcast series called ‘Towards A Feral Free Future’.