Invasive species lead driver of biodiversity loss in Australia – and feral cats have biggest impact, report finds
Advocates are calling for an urgent and coordinated national response to the threat of invasive species after the coauthors of a major international report identified it as the leading driver of biodiversity loss in Australia.
The report, from the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), was produced by 86 experts from 49 countries and details the impacts of invasive flora and fauna on ecosystems globally.
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More than 37,000 alien species have been introduced by human activities to regions around the world, the report found. Of these, 3,500 are considered invasive alien species, causing negative impacts on nature and humans through their establishment and spread.
Australasia has been identified as a global hotspot for invasive species.
“In Australia, invasive species are the number one driver of biodiversity loss,” said report co-author Prof Phill Cassey of the University of Adelaide in a press briefing. Feral cats have the greatest environmental impact, he said, adding that European rabbits were the country’s most damaging agricultural pest.
Australia has lost more native mammal species than any other continent, with more than 100 species listed as either extinct or extinct in the wild.
Research published earlier this year by the Invasive Species Council found there has been an average of 4.5 probable extinctions a decade since the 1960s, with around three extinctions a decade mainly attributable to invasive species.
Responding to the IPBES report, Bertie Hennecke, Australia’s chief environmental biosecurity officer, said invasive flora such as buffalo and gamba grass in Australia’s north “have allowed bushfires to burn even hotter and destroy surrounding habitats”.
“Since 2021-22 … we have identified over 28,000 pests and diseases and weeds that have arrived at the border through cargo vessel, mail and traveller pathways,” Hennecke said.
Research led by Australia’s national science agency, the CSIRO, has previously found that invasive species have cost the economy $390bn over the past six decades.
Prevention was more important than managing invasives after they have already become established, the IPBES report co-authors emphasised.
“Particularly in Australasia, we have a good track record in effectively managing alien species,” said Dr Andy Sheppard, chief research scientist at the CSIRO and a coordinating lead author of the report. “Prevention is by far the most cost-effective means to stop invasive alien species from starting to have impacts in the first place.”
In August last year, Australia launched a national biosecurity strategy to combat the risk posed by invasive species to biodiversity, but experts say more coordinated legislation between jurisdictions is required.
“In Australia, we … suffer from legislation and regulation that differs state by state, and I think that that’s a real problem for managing a lot of these species that are already in Australia,” Cassey said.
In light of the global report, the Invasive Species Council has called on the federal government to establish an independent body to coordinate environmental biosecurity responses, and to increase funding for the federal chief environmental biosecurity office in order to “stop new invasions and deal with existing threats like fire ants and feral deer”.
Lyall Grieve, conservation and biosecurity analyst for the Invasive Species Council, said in a statement: “This report makes it clear that the Albanese government’s commitment to ‘no new extinctions’ will be no more than a slogan without increased focus and funding needed to prevent the next wave of invasive species.
“Invasive species are likely to be a primary driver of 85% of the next round of predicted vertebrate extinctions over the next 20 years,” Grieve said.
“Our geographic isolation means we are home to species that occur nowhere else on earth, but this unique web of life is also very vulnerable to invaders like feral cats, fire ants or new fungal diseases like myrtle rust.
“The free ride for importers who create the risk of potentially devastating invasives entering Australia must end so that we can source increased and sustainable funding.”
The environment minister, Tanya Plibersek, said feral and invasive species including cats and gamba grass did “enormous damage to our precious native plants and animals”. She said cats killed nearly six million reptiles, birds and mammals every night in Australia, and were “the single most pervasive threat to iconic species like the greater bilby, northern bettong and western quoll”.
“That’s why tackling feral cats, foxes and other invasives is a priority for the Albanese government. It’s one of the core goals of our threatened species action plan supported by our $224.5m saving native species fund and $1.1bn National Heritage Trust,” she said.
Sheppard also expressed concerns about the “emergence of high pathogenic avian influenza, which is spreading around the world”.
“It has already killed over 100 million wild birds in the northern hemisphere, and we’re very concerned, obviously, of the impacts when, rather than if, this gets to Australia.”