Source : Perth Now news
Cats are already decried as Australia’s most lethal extinction drivers but the native species death toll they inflict may be far greater than thought.
Advanced DNA analysis of feral cat diets has revealed evidence of mammal remains in 75 per cent of test samples.
The finding compares to a 43 per cent return using conventional methods.
The University of NSW research was conducted at conservation reserves in northern South Australia and far western NSW.
The stomach contents of 71 euthanased cats were examined, with more than three times the number of bird species identified and twice the number of mammal types.
Among them, researchers found evidence of the cats having preyed upon the threatened central short-tailed mouse and iconic bilby, neither of which had been previously detected.
“DNA technology is giving us a much clearer picture of the true scale of the damage,” according to Invasive Species Council chief conservation officer Tiana Pirtle.
“Feral cats are estimated to kill more than 1.5 billion native animals annually and threaten more than 200 nationally-listed threatened species.
“This research suggests the true toll may be even greater than we’ve been able to measure.”
The council says the findings reinforce an urgent need for state and federal governments to accelerate feral cat control Australia-wide.
Cat diets are typically assessed by manual inspection but some prey can’t be identified because their remains are too degraded.
However the UNSW study used a process known as DNA metabarcoding, in which genetic material is extracted and sequenced from mixed samples to determine which species are present.
“The science keeps getting clearer but our response hasn’t kept pace,” Dr Pirtle said.
“Governments need to match the scale of this crisis with sustained, co-ordinated investment.”
Island eradications have become one of the more effective conservation investments in managing the problem.
State and federal contributions, along with a philanthropic top-up, will see almost $4 million sent the way of one project in South Australia.
Its aim is to totally eradicate cats from the eastern end of Kangaroo Island, Australia’s third-largest, by 2030.
Their removal will create a permanent haven for threatened species such as the Kangaroo Island echidna, southern brown bandicoot and hooded plover.
It will also mean the largest human-inhabited feral cat-free area anywhere in the world.
Throughout the program, which began in 2015, the Dudley Peninsula has been isolated from the rest of the island by a three-kilometre cat-proof fence to prevent reinvasion.
A remotely monitored trap network, AI cameras, cat detection dogs, thermal drones and a community call program have also featured in efforts to remove the interlopers.
Expanding such efforts alongside co-ordinated mainland control will give many threatened species a genuine chance of survival, Dr Pirtle said.
Keeping cats safely at home would also give native bird populations a better chance of withstanding the additional pressure bird flu will bring, she added.
“It’s one practical step governments can take right now to improve wildlife resilience.”
Some 45 Australasian animal species in total have gone extinct over the past two centuries, largely due to the impacts of introduced cats and foxes, landclearing and other human factors.
