LOCK it up and leave.For years that single sentence has framed much of the environment debate.
It has been the philosophy behind banning cattle from the high country, sheep from former farms that have become national parks and even fishermen from marine parks.
The belief is that by removing introduced species of animals - and sometimes humans - nature will restore everything to a utopian balance.
It is also a line thrown back at conservationists every time a rabbit darts out of a blackberry bush in a national park, or a lamb is mauled by a wild dog that appears to be taking refuge on crown land.
But now, a tiny flightless bird may have turned the debate on its head.
In the last 12 years the Victorian Government has bought more than 11,000ha of farm land in north-central Victoria in an effort to save the Plains Wanderer, a small bird that resembles a quail.
The sheep were kicked out and the land turned into national parks.
The theory was the sheep were grazing the grass the Plains Wanderer needed to shelter in to survive.
The land purchases coincided with the drought, so there was little grass in that part of the world and the Plains Wanderer happily wandered around its new digs unimpeded by sheep.
But rain over the past few years saw huge grass growth in the parks. Too much growth, with the Plains Wanderer unable to dart in and out of the tussocks.
So they left.
And no one is sure where they have gone.
The state's leading expert on Plains Wanderers, ecologist David Baker-Gabb, scoured the protected grasslands last month to check on their progress.
"I couldn't find one, they're gone,'' he told The Weekly Times.
Dr Baker-Gabb is a former director of Birds Australia and manager of threatened fauna for the then Department of Conservation and Environment, so he knows his stuff.
There was only one conclusion that could be drawn - the Plains Wanderers need the sheep to keep the grass down so they can survive.
Dr Baker-Gabb said simply buying farms and closing the gate hadn't worked.
"The grasslands need to be managed a lot better than we are doing at the moment.''
So the government and its departments recently sent sheep back in to graze the parks - and hopefully save the Plains Wanderer.
There is even pressure on the Government to buy its own flock of sheep to graze parks. That would be the ultimate turn-up for the books.
The implications of this is enormous.
The Plains Wanderer has severely damaged the environmental movement's chief argument for many lock-it- up-and-leave strategies over the past two decades.
You can already see the supporters of cattle in the high country and Barmah Forest on the Murray sharpening their arguments for a return to grazing.
But the real issue here is the science.
How could they get it so wrong with the Plains Wanderer and sheep grazing?
It was unquestioned that getting rid of the sheep would save the bird.
Millions of dollars were spent buying farmland to return it back to its natural state.
The Plains Wanderer has now shown this could have been a waste of money and that "natural'' may not be best.
So now we ask, is banning fishing in marine parks going to cause more problems than it solves?
Do we now doubt the science behind sending irrigation water down the Murray Darling river system to return it to a "natural'' state?
Will more frequent flooding along the Murray do more harm than good?
And, of course, there's the mother of all issues, the science around climate change.
If they stuffed up the Plains Wanderer, what else will they stuff up?
The Plains Wanderer might be a tiny bird, but it just might landed a killer blow in the environment debate.