‘Inappropriate’ back-burns could drive species extinct
Scientists warn that the wrong fire patterns could see more losses of threatened species across the country.
IN LATE JANUARY 2014, after wildfires tore through two conservation parks in South Australia, researchers scoured the charred terrain for signs of life.
They hoped to glimpse a mouse-sized flicker of blue and gold or hear a high pitched territorial call. But they found nothing; only the vaporous silence of an empty landscape.
The 60 remaining breeding pairs of Mallee emu-wren (Stipiturus mallee) in South Australia had been lost and the species was now extinct in the state.
“There is nothing left of an emu-wren after a fire, not even a pile of ash,” says Professor Michael Clarke, head of Life Sciences at La Trobe University.
“People are moved by a koala with burnt paws but what they may not understand is that if we get it wrong a whole species could disappear from the planet during a single fire event,” he says.
Fire is an important part of the Australian environment, but it is the changing pattern of fire, such as the increase or decrease in its frequency, patchiness and intensity that is having the greatest impact on some of our most threatened wildlife.
Reports published by the CSIRO and BirdLife Australia (pdf) cite “inappropriate fire regimes” as threatening more than 50 Australian mammal and 50 Australian bird species.
Climate change is also said to be playing a role, with the biennial Bureau of Meteorology and CSIRO State of the Climate Report 2014 finding that rising greenhouse gas emissions are causing fire seasons to lengthen and are contributing to an increase in the number of fire risk days, particularly in the south-east of Australia.
University of Tasmania Professor, Chris Johnson, says for threatened species it is the combination of ongoing habitat loss and more intense fires that can be fatal.
“We have cleared so much already that there is often not much habitat there to start with and when a wildfire does come through these animals have nowhere to go,” he says.
In 2009, the Black Saturday bushfires almost wiped out an entire population of perhaps 300 Leadbeater’s possums at Lake Mountain and burnt through 43 per cent of the species’ protected habitat.
Now after years of logging and the loss of many hollow bearing trees, this endangered species is highly vulnerable to extinction by fire.
But after the devastation of the 2009 Black Saturday bushfires, the Victorian Bushfire Royal Commission set a yearly target to burn five per cent of public land to reduce bushfire risk across the state.
However, expert witness for the Royal Commission, Professor Michael Clarke from La Trobe University argues that the five per cent target is not doing anything to improve public safety and is in fact doing ecological harm.
“Modelling with collaborators at the University of Melbourne predicts that burning five per cent of the Murray Sunset Park annually will increase the risk of extinction of 22 fire sensitive species by at least three-fold in the long term,” he says.
“They choose to burn in remote areas like the Mallee because it is safe to burn there but it is not actually making people safer because no one lives there, instead it has become an inappropriate fire regime in many parts of the state,” he says
Call for federal leadership on fire
Some scientists are also calling for federal leadership on Australian fire management, starting with the listing of “inappropriate fire regimes” as a key threatening process under the Environment Protection and Biodiversity Conservation Act (EPBC Act) so that a national plan can be established.
BirdLife Australia’s head of conservation, Samantha Vine says that planned burns need to be more strategic to leave habitat for threatened species.
“Generally mosaics are what you are looking for. When a fire goes through you may have some loss but it will create fire breaks as well as neighbouring habitat patches where species can cling on and survive,” Ms Vine says.
In Northern Australia, it was largely indigenous Australians who created these habitat mosaics by burning small patchy fires to break up the landscape, decreasing the risk of bigger, hotter fires moving through.
Since the decline of these traditional practices, along with other environmental changes, Northern Australia has experienced huge mammal collapses over the last couple of decades.
University of Melbourne’s, Dr Brett Murphy is currently conducting research on the interaction between feral cats and fire in the north, which he says is the major cause of small mammal decline.
“There is a general acceptance that fires are becoming hotter overtime. Hot fires burn up logs and shrubs and make the habitat more open so feral cats can hunt more effectively.
“So we need to look at how we can manage fire better to allow for at least five years of unburnt habitat so mammals can survive,” Dr Murphy says.
Digging species could reduce fire risk
In some parts of the country, research is suggesting that areas still home to digging animals such as lyrebirds, malleefowl, bettongs, bandicoots and bilbies also contain natural fire breaks and are more resilient to large scale fires.
Much of this research is still in the early stages but some scientists believe that the reintroduction of digging animals in some areas could play a role in fire management and possibly fire safety in the future.
Associate Professor at Murdoch University, Trish Fleming, is currently identifying housing sites in suburbs south of Perth to study how reintroduced southern brown bandicoots change urban fire dynamics.
“If you had a bush area next to your house that could support bandicoots, we want to test whether or not your house is more protected because they will be there turning over the leaf litter which would otherwise carry a fire,” Professor Fleming says.
It may that a lack of digging marsupials leads to the kinds of fires that in turn endanger other marsupials.
ABC Environment 2 Mar 2015
Originally Published at http://www.abc.net.au/environment/articles/2015/03/02/4185527.htm