The estimate that one billion Animals were killed by the 2019-2020 black summer fires in Australia have drawn international attention to the plight of wildlife during the fires.
This estimate assumed that all animals in the path of the blaze had been killed by the flames, or immediately thereafter due to injury, predation, dehydration, or starvation.
However, our new to research, published today in Biology of global changesuggests that, on average, the vast majority of animals (over 90%) survive the immediate passage of a typical fire. But there are few studies on the survival of animals during catastrophic fires, such as those seen during the black summer in Australia.
We urgently need data on how animals cope with megafires, given that they are should increase in a warming world.
How do we know how many animals are killed by fire?
How do researchers really know the fate of wild animals exposed to fire? The most reliable way is to track animals wearing radio or GPS collars.
When fire passes through a landscape, animals in its path unable to flee or find shelter often die from the flames, radiant heat or smoke. By tracking these individuals, as well as those who survived, we can calculate the proportion of animals that live and die in a fire.
We have systematically reviewed all studies tracking animal survival in fires around the world. The 31 studies we found were largely from Australia and North America. The fires included planned burns, as well as opportunistic studies where an unexpected forest fire passed through an existing animal tracking program.
The studies have mainly followed mammals and reptiles, although some have included birds and amphibians. Animals studied ranged from the small red-backed wren weighing just 8 grams to African bush elephants, the world’s largest terrestrial vertebrate weighing up to 4.4 tonnes.
So what did we find? The most remarkable result is that almost two-thirds of the studies (65%) found no animal deaths directly caused by the fires. It turns out that animals are surprisingly good at avoid oncoming fire. Some animals may have evolved these tips overtime.
Importantly, the 31 studies often followed only a handful of animals (half followed fewer than ten individuals), with wide variation in death rates. In one study, for example, up to 40% of rattlesnakes were killed. However, this study only followed five snakes, two of which perished in the blaze.
When we aggregated the studies, we found something of interest. On average, fires killed only 3% of hunted animals. This figure rose to 7% for studies monitoring animal survival during high intensity fires.
Not all fires are the same, and some animals survive one type of fire but succumb to other fires. Take frilled lizards, which usually take shelter in the canopy of trees during fires in northern Australia. When they used this tactic in cool fires at the start of the dry season, all tracked lizards survived.
When more serious fires occurred later in the dry season, a quarter of the lizards were killed. Many of those who remained were killed by flames that scorched the canopy. Those who are savvy enough to take shelter in termite mounds have survived.
The silver lining: all is not lost after the fire
When you read a headline about the number of animals killed in fires, it can be easy to despair.
That’s why we think our research is good news. Why? Because it means there may be a narrow window of opportunity after the fires to have a real impact, helping the animals survive the difficult post-fire period.
You may remember stories of helicopters dropping sweet potatoes and carrots on hungry wallabies immediately after the Black Summer fires.
Our research suggests now is exactly the time to act to help as many wildlife as possible.
This is because the post-fire landscape is exceptionally difficult for the surviving wildlife. For months, the house became hostile to animals.
It is very difficult to find shelter as food and water are also scarce. Predators roam, looking for easy pickings.
So what can we do? Efforts to reduce these dangers are essential, such as supplementing with food and water, and even giving up temporary shelter options. Controlling foxes and cats can also help.
Taken together, this package could help save endangered species from forest fires, even severe mega-fires. But these interventions must be monitored to assess their effectiveness.
Can animals cope with mega fires?
Right now, we know next to nothing about animal death rates during catastrophic fires like the mega-fires that rage during the black summer.
Although animals can survive a typical fire, there are increasing number of instances fires around the world that exhibit extreme behavior. For example, the many firestorms that occurred during the black summer probably left a narrow path for the survival of many species.
We simply lack the data to provide justifiable estimates of the number of animals killed in such large areas in such extreme fires.
As climate change intensifies, mega fires are likely to become more frequent. Even if populations are resilient to individual mega-fires, their cumulative impacts may gradually erode that resilience. We must also take into account the major impact that fires can have on habitat, which can last decades or centuries.
We urgently need to find ways to help wildlife before and after these fires.