Australia has the worst record of mammal extinctions of any country on earth with about half the world's losses coming from this country in the past 200 years. That's sad but a lot of the cause of losses were from naivety due to late settlement by Europeans and by a lack of knowledge of the unique wildlife, that had evolved so far away from the rest of the world.
Invasive animals have often been involved, though often not as the primary driver of extinction. Often human activity like taking away habitat has led a species to the execution room and an invasive animal might have flicked the switch on the electric chair. That analogy is probably too blame-laden: naivety is usually a big factor, where we haven't realised the problems until it was too late.
The really sad thing is that extinctions are continuing, with the first mammal since the thylacine on the edge. The tiny Christmas Island Pipistrelle bat is almost certainly the next mammal to go. The reasons for the demise of the insect-eating microbat are not fully understood. Christmas Island has a large number of invasive species to deal with, including the common wolf snake, the ship rat, the feral cat, the giant centipede and yellow crazy ants, all of which could be preying on the bats which nest under bark of trees. A lot of the bat's habitat has been lost.
The pipistrelle has been in steady decline since 1994 and was predicted to become extinct during 2008. A survey in January this year has identified that probably as few as 20 individual bats are still alive. Experts say they might all be gone in six months, so we should begin a captive breeding program immediately. Twenty individuals is a place few species have returned from, but it would be well worth a try.
Authorities have made excellent progress on containing the yellow crazy ant outbreak on Christmas Island. We also know how to get rid of ship rats from islands and hopefully will demonstrate that on Lord Howe and Macquarie Islands in the next few years. So if an "ark" program can save those bats, we probably could reintroduce them to a better future at some stage. Would be very cool if they got pulled back from the brink. Here's hoping.
More on the Australasian Bat Society site.