A tiny native mouse that lives in one of Australia's harshest environments will have to dig deep to survive predicted temperature rises over the coming decades, according to new research from UWA.
Temperatures are on track to rise 3C by 2050 in the Pilbara region, where the elusive western pebble mouse makes its home in a complex burrow system topped by a mound made up of hundreds of pebbles that the female pebble mouse shifts itself.
Currently the burrows are believed to run to a maximum depth of about 60cm, but a new study from UWA behavioural ecologist Dr Renee Firman suggests pebble mice may have to dig up to a metre underground to survive in the future.
"The predicted depth required to escape the heat of future summers – 100cm – is striking," Dr Firman says.
The pebble mouse is a keystone species – really important for the ecosystem – and once you start losing species like that, things can start shutting down fairly quickly.
Dr Renee Firman
"If those burrows are getting to 60cm now and in another 25 years we're expecting them to go to a metre, it's kind of concerning. I'm not sure they would be able to do that – there could be a massive decline in the population."
Dr Firman started her career studying sex selection in invasive house mice but in recent years switched to studying how native rodents in arid and semi-arid areas are responding to climate change.
"I think we're all fairly certain now: things are bad, but they're only going to get worse," she says.
"That's obviously going to have massive implications for humans but as a zoologist, my primary concern is how animals can respond to those changes.
Image: The pebble mouse. Image credit: Aline Gibson Vega.
"I was particularly drawn to the western pebble mouse, I guess because it's a WA mouse and I'm a West Aussie myself, plus they build these fascinating burrow systems to form a mound."
Those systems buffer the pebble mouse from some of Australia's most extreme climatic conditions, with the Pilbara region regularly recording daytime summer temperatures of more than 43C.
"The burrow-mounds are a massive resource not just for the individual females who build them, but their offspring, successive generations, and other non-burrowing species that need refuge," Dr Firman says.
"We've found little marsupials like dunnarts using them, other rodent species like sandy inland mice, lots of skinks and invertebrates.
"In a way the pebble mouse is a keystone species – really important for the ecosystem – and once you start losing species like that, things can start shutting down fairly quickly.
"That's obviously not going to have a huge impact on people living in the city, but if we want a world that's full of wildlife, we need to care about those ones that are doing amazing things like creating habitats."
The little-studied western pebble mouse currently has no conservation status but is listed as a species in need of monitoring.
"I'm on a bit of a current mission to get their conservation status reassessed," Dr Firman says. "Being restricted to the Pilbara region, they're very much impacted by mining activity and feral species, and my concern is those things are not only destroying individuals, they're destroying the mound systems they rely on."
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