Scientists have long puzzled over the rapid loss of Australia’s land mammals. After all, the country is huge and sparsely populated in most areas, which means that many of the continent’s animals should be isolated from one of the leading causes of species decline—interaction with humans. Yet the extinction rate of Australia’s mammals remains unusually high.
Now, a recent study reports that, since colonization began in Australia in 1788, 30 of the continent’s 273 native land mammals have gone extinct. That’s about 10 percent, or one to two extinctions per decade. As the International Business Times reports, researchers also found that “Another 21 percent remained threatened and 15 percent were near threatened."
“We knew it was bad, but I think our tallies were much worse than previously thought,” study co-author John Woinarski of Charles Darwin University told the Associated Press. The study was published in the Proceedings of the National Academy of Sciences.
The researchers also pinpointed the likely culprits behind much of this decline: red foxes and feral cats.
Both were originally introduced by European settlers—the cats were initially used by sailors to keep ship rats at bay; foxes were brought over for hunting purposes. But both animals are effective predators, and both favor smaller prey, of which Australia had in abundance. The study found that their arrival and spread throughout the continent coincided with the rapid decline in native species. That includes animals like the desert rat kangaroo, two kind of bandicoot, four varieties of wallaby, the dusky flying fox and a number of mice and rat species.
So how do we stop this trend? The study says that some recent conservation efforts, like the relocation of threatened species into isolated or protected areas, have had some effect. But, they say, more needs to be done, particularly when it comes to controlling the numbers and ranges of cats and foxes.
But, as IBT reports, we can’t go blaming all extinction problems on these two animals. Pollution and overuse of water are also among factors contributing to the loss of certain species. What will help make a big impact, researchers conclude, is a widespread public appreciation of biodiversity—even in terms of small, often unseen animals. As they point out, “if such high rates of extinction of mammals are condoned in Australia, there may be little hope for the world’s biodiversity more generally.”