More resources are needed to monitor the 100 recorded smoky mice, or Pseudomys fumeus, in the wild in tiny populations in Victoria and NSW
Scientists in Victoria say more resources are needed to monitor the critically endangered native smoky mouse, before the rodents “go extinct without us looking”.
There are only about 100 recorded smoky mice, or Pseudomys fumeus, in the wild, dotted in tiny populations in the Grampians, Central Highlands and East Gippsland in Victoria, and around Kosciuszko national park and Nullica state forest in New South Wales.
Without a captive population, those colonies, each of an unknown size but consisting of no more than 30 recorded individuals, are the only chance for the survival of the species.
But a discovery last year of seven smoky mice in a remote gully in the Grampians has given researchers new hope for their resilience.
The mice were trapped by a team from Parks Victoria and Museum Victoria in an area where 28 smoky mice were found in 2012. Before that discovery, only 40 of the animals had been sighted in the Grampians in the previous 40 years.
But a bushfire burned out that gully soon after and subsequent surveys showed numbers had dwindled to nine in late 2013, then three in 2014. Those findings were published in the Csiro’s Wildlife Research journal this month.
“This year [in 2015] we were going back with bated breath – we thought this would be the year that we would not catch any mice,” Ben Holmes, coordinator of the Grampians Ark project for Parks Victoria, told Guardian Australia.
Instead they found seven, including the same three that had been trapped in 2014.
“That’s perceived to be a very strong survivorship and somewhat surprising,” Holmes said. The 12cm-long, 50-gram rodent with soft charcoal fur and a long white-tipped tail is an ideal snack size for a fox or cat.
Holmes said animals in that critical weight range don’t often live longer than a year, and their survival could be down to the success of widescale fox-baiting and feral cat eradication as part of the Grampians Ark project. Or, he said, it could be due to something else – there has been so little study of the smoky mouse that scientists were “barely scratching the surface” of what was driving changes in its population.
Dr Kevin Rowe, senior curator of mammals for Museum Victoria, said the lack of programs to monitor the species and track its progress meant scientists could not definitively say what its most urgent threats were, or even whether it was in decline or recovery. It is not known why the animal became extinct in the Otways ranges near Geelong, where it has not been spotted since the 1980s.
“It is a pretty significant concern of people who are trying to make sure we keep an eye on the smoky mouse to make sure they don’t go extinct without us looking, which is really what has happened to them in some of these other places,” Rowe told Guardian Australia.
He said the animal itself, despite its unpopular relatives in the rodent family, was “really just lovely”.
“They actually smell really nice,” he said. “Males especially smell like a kind of smoky burnt vanilla, and they have really nice calm temperaments … they are just really great little animals.”
Holmes said populations of other critically endangered species in the Grampians – the southern brown bandicoot, long-nosed potoroo and heath mouse – did appear to be benefiting from a reduction in the number of foxes and cats, so it was assumed the same applied to smoky mice.
“All those species ‚Ä¶ and even more established species like the bush rat and the antechinus, have all declined significantly over the last couple of years, and we believe that’s due to the very low rainfall we have had,” he said.
“Without the fox baiting it’s possible that the effect of predation during those low-number periods could have led to the smoky mouse becoming extinct in this area, as they have in the Otways.
“There are persisting and that’s kind of all we can ask for at this point of time, until it rains.”