Fighting to save our small native mammals

Native small mammals have been disappearing across Northern Australia. Alex Carey wants to make sure these creatures survive and thrive well into the future. 

Biodiversity conservation has been a life-long interest for Alex, a Higher Degree by Research student at Charles Darwin University. 

“Learning about and observing the shrinking of wild places for development and the disappearance of unique species that took millennia to evolve came as a shock and a call to action.”

He studied a Bachelor of Biodiversity and Conservation and a Master of Landscape Genetics before joining the NSW Government’s ‘Saving Our Species’ conservation program. 

When contemplating his PhD, he naturally looked to the Territory, home to native small mammals like bandicoots, possums and tree rats.

“The ongoing mammal declines across Northern Australia mean this is the place to meaningfully contribute to conservation.”

Why are these creatures disappearing?

Alex notes a number of reasons for declining numbers: predation by feral cats, grazing by feral buffalo, and, the focus of his research, large and hot fires destroying the vegetation where these animals seek refuge.

“Disruptions to historic conditions such as introduced species or altered fire regimes are occurring globally with the connectedness of humans, loss of traditional land management, and the effects of climate change.”

He wants to understand how to help these native species persevere in the face of such overwhelming change. 

“Australia already has the worst record of mammal extinctions and the loss of more of our unique fauna would be tragic.”

Firing up the conservation effort 

Fire ecology is of particular interest to Alex, whose research revolves around post-fire responses of declining mammal populations on the Tiwi Islands. 

Fire management like early dry season burning has already been put in place to reduce the size and intensity of these fires, but it’s not yet doing enough for conservation efforts. 

“A key knowledge gap is understanding how native small mammals respond to fire events and can persist in landscapes that frequently burn.”

In collaboration with the Tiwi Land Council and Tiwi rangers, Alex conducts much of his fieldwork on the Tiwi Islands, one of the last refuges of native mammals in the region. 

As part of his research, he conducted a fire experiment to understand how different species respond to and recover from a fire event. 

“It involved trapping native mammals before fire, immediately after fire, and one year after fire. The controlled fires were conducted by the Tiwi rangers to ensure only half the sites were burnt. I collected genetic information to determine how the animals moved in response to the fire and how the populations are able to recover and persist in these fire-prone landscapes.”

Additionally, the Tiwi Marine Rangers and Traditional Owners of the Yimpinari Clan took Alex by boat to the remote northeastern peninsulas of Melville Island to trap native mammals in an area that had never been surveyed.

“These remote peninsulas experience less fire and potentially reduced threats from feral cats. It will be interesting to compare the genetics from here to the rest of the Island and identify whether fire influences these genetic patterns.” 

Future impact

“The outcomes of this work will be of direct interest to land managers such as Indigenous groups, conservation agencies, and national parks across Northern Australia. It will be able to guide their management decisions, particularly around fire management.”

On a larger scale, Alex’s work highlights some fundamental principles of how mammal species survive in fire-prone environments.

“I hope my findings can help Northern Australian conservation and even be of use in other biomes and for other species undergoing declines.”

Hero photo credit: Matthew Hammond

CDU is seeking Higher Degree by Research students to take part in research projects just like these. Scholarships are available. Learn more.