Endangered Smoky Mouse Defies the Odds in Grampians National Park
Friday 15 January, 2016
Museum Victoria and Parks Victoria researchers welcome news that the Smoky Mouse, one of Victoria’s most endangered native mammals persists in an isolated population of the Grampians National Park.
Results published today in the CSIRO journal Wildlife Research reveal that a resilient population of Smoky Mice has persisted for over 40 years in a small area of the Victoria Range in the western Grampians National Park, despite substantial impact from drought, feral predators, and bushfire.
In 2012, during a two week Bioscan, Museum Victoria and Parks Victoria staff discovered a healthy population of 28 Smoky Mice in one drainage of the Victoria Range; over the previous 40 years fewer than 40 individuals had been recorded from across the entire Victoria Range. This was welcome news since in 2008 at the height of the drought surveys failed to detect the species at sites where they had been recorded since the 1970s.
In 2013 the 35,000 hectare Victoria Valley fire devastated every site where Smoky Mice had been recorded in the Victoria Range. However, the study found that following the fire Smoky Mice survived and reproduced within the burn scar, while other small mammals recorded in 2012 disappeared.
The study reported a worrying trend with the 28 Smoky Mouse individuals at the 2012 site dropping to nine in 2013 and three in 2014. Fortunately, surveys in 2015 that were not reported in the study found an increase to seven individuals at the site with all 3 individuals surviving from 2014. Other sites surveyed in 2015 showed similarly high survival with 24 individuals detected across four sites in the Victoria Range.
This is amazing survival for any mouse – especially a 50g animal – but extraordinary for a species under threat from feral predators in a landscape inhabited by foxes and cats, and also recovering from bush fire and drought.
“The survival of Smoky Mice in the Victoria Range is great news. We didn’t expect to see the population persist and to see 100% annual survival two years after the fire is astounding. We know of at least three individuals that have survived for over two years in this charred landscape, which is about the maximum reported for the species under ideal conditions,” says Kevin Rowe, Senior Curator of Mammals, Museum Victoria.
The survival of the Smoky Mouse is testament to the value of Parks Victoria’s Landscape predator control program, Grampians Ark, for reducing the impact of predator numbers in the area.
“We are fortunate to have had long-term commitment to an extensive fox control program across the Grampians landscape which focuses on protecting threatened species like the Smoky Mouse. Research collaborations such as this are invaluable in monitoring and evaluating the success of our management efforts but also to understand the impacts of fire, floods and a changing climate,” says Ben Holmes, co-author and Parks Victoria Grampians Ark Coordinator.
Holmes continues: "The Grampians National Park is one of Victoria’s most important biodiversity reserves, containing many threatened plants and animals. Its natural values attract many domestic and international visitors every year. Research like this is critical in helping Parks Victoria manage the biodiversity."
Another major finding of the study was that historical survey efforts have been inadequate to chart changes in the sites occupied by this endangered species in the Victoria Range. The study cautions that ongoing surveys are needed to better estimate the number of Smoky Mice and to track populations while they are still present. The Smoky Mouse may have completely disappeared without regular surveys in other areas where they were previously recorded including the Otways, ACT and Far East Gippsland.
But how endangered really is ‘endangered’? Across the species’ range approximately 100 individuals have been recorded in the last few years.
As Dr Rowe says, “While there are certainly more than 100 Smoky Mice we just don’t have the data to even estimate how many there are. We still know so little about the basics for this endangered species.”
Interviews are available with Kevin Rowe, Museum Victoria and Ben Holmes, Parks Victoria.