"The conventional wisdom is that medium-sized mammals and birds are most vulnerable to foxes, and this is certainly the case," said Dickman. "But it is becoming clear that foxes also take small mammals and harass larger animals like grey kangaroos, forcing them to drop their joeys [babies] in fear."
Foxes also carry and transmit several diseases, eat and spread seeds from noxious weeds, and kill livestock.
A Desperate Race
Two foxes were shot in northern Tasmania in 2001; since then hundreds of sightings have been reported. What many had been dreading had happenedfoxes had made it onto the Ark.
There is evidence indicating that several litters of fox cubs were intentionallyand illegallysmuggled on to the island, reared, and then released at several locations across the state.
"It's more or less eco-terrorism," said Nick Mooney, scientific advisor to the Tasmanian Fox Free Taskforce set up in 2001 in response to the emergency.
Wildlife biologists estimate that there are probably 10 to 20 foxes currently in Tasmania. The taskforce has 21 full-time employees manning a telephone hotline, responding to reported sightings, conducting a statewide education campaign, and coordinating efforts to find the foxes and to prevent any further introductions.
The sense of urgency is motivated by the fact that foxes mate in winter, and most cubs are born in spring. Over the summer, which is December to February in the southern hemisphere, the fox cubs become independent and establish their own territories.
"It's a pretty important time, because if they've bred, now is when the pups will turn up," said Mooney. "If we can get through this summer and autumn without any sightings of pups, that will be great news."
So far no young foxes have been seen. But as Mooney points out, foxes are very secretive and quickly learn to avoid people and risky situations. This makes eradication by shooting impractical when the population is relatively small.
The taskforce made the difficult decision to use baits laced with poison in areas where the foxes have been reported. Using poison bait poses some danger to native fauna, but the alternative is much worse, said Mooney. Various safety measures, such as burying bait deeper than native species usually dig, have been put in place to minimize the threat to native carnivores.
"We need to have a whole community that understands how bad [having foxes in Tasmania] this is, so that it can't happen again," said Mooney. "As it is, we will have to stick at this [control program] for years, to make sure the foxes haven't established."
The stakes are high.
"If foxes establish, and native species are lost from their last remaining refuge in Tasmania, then there's no more hope for them," said Dickman. "Extinction really is forever."
SOURCES AND RELATED WEB SITES