Unprecedented Australian wildfires have extracted a heavy toll from the continent’s unique wildlife, with an estimated 1 billion animals killed, 10.7 million hectares (approximately 41,300 square miles) burned on the east coast, and more than 150 fires still burning in two states alone, according to news reports and the Australian government.
News reports featuring shocking images of injured and dead wildlife, such as kangaroos, koalas, and birds, have dominated headlines in Australia.
“It’s difficult to comprehend the impact that it’s having,” says Natasha Speight, a koala disease researcher and veterinarian at the University of Adelaide in South Australia, whose study populations of koalas have been affected by the fires.
There are particular concerns for the koalas found on Kangaroo Island, off the coast of South Australia, which are unique in being the only known population of koalas in Australia that is free from chlamydia—a major disease contributor to koala death.
There were an estimated 50,000 koalas living on the island. However, recent fires have burned around one-third of the 170,000-hectare island, and large numbers of injured and dead animals are being discovered, with survivors being treated by local wildlife rescuers.
The disaster could not have come at a worse time for a species that is already classified as vulnerable by the IUCN. “There’s been so much research progress in recent years to try and improve the health status of these koala populations,” Speight tells The Scientist. “It really is a setback to have so many lost from these bushfires.”
In the World Heritage–listed wilderness of the Blue Mountains in New South Wales, ecologist Roger Lembit from Gingra Ecological Surveys has just inspected the unique and vulnerable swamps he has been monitoring for more than 20 years, and which were also scorched by fires in late December. The swamps are home to the endangered Blue Mountains water skink (Eulamprus leuraensis) and Giant Dragonfly (Petalura gigantea).
Here, the news is better. “The fires really only skimmed across the top, it hasn’t burned deeply into the peat,” Lembit says. Some of the burned grasses are already resprouting. He is cautiously optimistic that the skink could have survived by burying into the moist peat as the flames went over. However, he has concerns that the ongoing drought—one of the worst since records began—makes these swamps particularly vulnerable to fire.
Even for a country used to fire, the scale and severity of this bushfire season is unprecedented.
“It’s certainly a major event, and one that we hadn’t seen the like of in modern times before,” says David Keith, a fire ecologist at the University of New South Wales Sydney.
He says he is particularly worried about the alpine ash forests of the Australian alps, which are one of the few eucalypt species that are killed by intense fire through the canopy, also known as crown fire.
“Most of our eucalypts have specialized tissues that enable them to resprout, usually from the branches or the base,” Keith says. In constract, alpine ash has thin bark that doesn’t have the same capacity, and instead relies entirely on seeds stored in the canopy.
While many mobile Australian species, such as kangaroos and wallabies, or plant species that disperse their seeds widely, are fairly resilient to fire, Keith says, the outlook for less mobile species is not good.
“Other animals like koalas or greater gliders, there’s no question that they’re going to be in trouble.”
Bianca Nogrady is a freelance science writer based in Sydney, Australia.