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Darwin residents keep toads at bay -

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Darwin residents keep toads at bay

Reporter: Murray McLaughlin

ALI MOORE: Only a few years, ago the pessimists were predicting cane toads would have invaded
Darwin by now. Introduced privately to north Queensland sugarcane farms from Hawaii more than 70
years ago, the toads were meant to be for pest control, but they failed and went on to become the
pest themselves. As they've migrated west from the sunshine state, the creatures have thrived in
the tropical Top End, colonising vast tracks of country at the expense of native Australian
wildlife. They're now only a year or so away from Western Australia. Although Darwin residents are
reporting occasional captures of the toads this wet season, an heroic organisation of citizen power
has largely managed to suppress numbers in the city. And as Murray McLaughlin reports, there are
now high hopes the nation's northernmost capital city may escape the cane toad ravage.

MURRAY MCLAUGHLIN: It's the wet season in the Top End, and cane toads are on the move. They've been
on the outskirts of Darwin for the past two years, but concerted civilian action has kept them
largely at bay from the city itself. A community group called Frogwatch organises regular wet
season raids on known toad habitats.

VOLUNTEER: This one is a girl.

MURRAY MCLAUGHLIN: Their success so far in keeping cane toads out of Darwin has confounded

GRAEME SAWYER, FROGWATCH: There's a huge amount of scepticism and still is. There's lots of people
out there that think you can't stop toads. The thing that amazes me about that is, we actually
spent a fair bit of time trying to find an example of where someone had actually tried to stop them
before and we couldn't find any. There's certainly no written up, documented cases of people
systematically trying to stop cane toads.

MURRAY MCLAUGHLIN: The westward advance of cane toads from Queensland across the Northern Territory
and into Western Australia has been building for decades. Even as native species like snakes and
goannas died in their wake, Government saw the expansion of cane toads as inexorable. Only for the
past few years have scientists been working to find a biological control. The CSIRO's Division of
Entomology in Canberra has its own colony of cane toads and scientists are studying their breeding
habits and life cycle. They're aiming to develop an agent which would work on cane toads after the
fashion of myxomatosis and the caliciviruses, which have effectively diminished Australia's feral
rabbit population.

DR TONY ROBINSON, CSIRO ENTOMOLOGY DIVISION: Unfortunately, we can't find a virus or an infectious
agent that will work without alteration, in other words an off-the-shelf control. So what we're
seeing if we can do is whether we can make one in the laboratory.

MURRAY MCLAUGHLIN: The work in Canberra is complemented by scientists at the CSIRO's high-security
animal health laboratory in Geelong. The work's been funded for the past five years by the National
Heritage Trust. Basically, scientists want to find an artificial way of interfering with the cane
toad's growth cycle.

DR JACKIE PALLISTER, CSIRO ANIMAL HEALTH LABORATORY: What we're trying to do is develop a virus
that will act as I guess you could call it a taxi, a vehicle for delivering a gene to the cane toad
that will actually stop the development of the tadpole into a toad. So the people we work with in
Canberra are working on finding that gene and we're looking at developing the virus, such that it
can deliver that gene.

MURRAY MCLAUGHLIN: While CSIRO scientists pursue long term technical options to control cane toads,
human intervention remains the only check to their migration west across the Northern Territory.

VOLUNTEER: Look at this one.

MURRAY MCLAUGHLIN: Near the town of Timber Creek over five weeks late last year, just before the
start of this wet season, more than 100 volunteers collected nearly 50,000 cane toads from a
500-square-kilometre flood plain system. The toads are only a year away from the WA border itself,
and Graeme Sawyer from Frogwatch says the round up taught valuable lessons about how the toad's
move might yet be impaired.

GRAEME SAWYER: There are only 15 water points in that flood plain system at that time of year and
all the cane toads were stacked around those water holes and they were in massive numbers. Off a
water hole that probably is about the size of three or four tennis courts we got 10,500 cane toads.
The force of our dry season is an absolute one for toads. They don't have any option. That was
really good news for us because, if toads were able to sit up in the rocks somewhere and wait out
the dry season before they moved on again then they were going to be almost impossible to control.
But they don't have that option, so that's really good news, as well.

MURRAY MCLAUGHLIN: Graeme Sawyer is checking a line of specially built traps at Hidden Valley on
the outskirts of Darwin city. Hundreds of traps designed to attract cane toads by fluorescent light
at night time have been bought or built by Darwin residents, and a network of disposal bins has
been established, where captured toads are dumped and then processed into fertiliser. The sheer
concentration of human effort to keep toads at bay from Darwin seems to be paying off.

GRAEME SAWYER: By all other measures this whole Darwin area should be really flooded in toads. The
public response is amazing, fantastic. We do toad busts around the place. We did one the other
night. With four or five days notice we get 50, 60 people come out to join in.

MURRAY MCLAUGHLIN: That public participation is now giving Graeme Sawyer heart to predict that
while native fauna have been ravaged beyond Darwin, the city itself will remain something of a
nature reserve.

GRAEME SAWYER: So they won't establish themselves in large numbers around Darwin and you won't have
to put up with hundreds of them around the golf course or around the footy oval or in your backyard
and you'll also hopefully still see reptiles walking around the parks in Darwin into the future,
because they won't have all been killed by cane toads.

ALI MOORE: That report from Murray McLaughlin.

(c) 2007 ABC