In this fantastic collaboration of over 100 Australian ecologists, we put together the world’s largest dataset about animal and plant responses to a single fire season. With these data, we’ve been able to ask questions that couldn’t be asked before.

We found that the impacts of the 2019-20 megafires on plants and animals depended on the condition of a site before the fire. Most importantly, it depended on the number of past fires.  If a site had not been burnt or burnt only once in forty years, plants and animals declined by around 12%. But if there had been three or more fires, they declined by 23%.

This poses a major management dilemma, because government agencies use frequent prescribed burning to try to reduce wildfire severity. But that also makes the impacts of subsequent bushfires on plants and animals twice as extreme. Agencies will really need to consider more extensive use of rapid wildfire suppression to try to limit impacts of more frequent fire.

But with accelerating climate change, these megafires are going to become larger and more frequent. The only real solution is to stop using fossil fuels and stop land clearing.

The Black Summer fires of 2019-2020 burnt massive swathes of southern Australia and its forests. The scientists had compiled an incredible database spanning >2000 species to document the complex, multifaceted nature of fire impacts on ecosystems. 

The evidence is quite clear that responses to fire become more extreme with past disturbance with the pendulum swinging wider. More fires in recent years, higher levels of drought impact, and less protected area were all associated with greater destabilisation. This greater variance is cause for concern and is one indicator and pathway of ecosystem collapse and has been documented in other contexts such as coral bleaching of the Great Barrier Reef.

Driscoll et al call for caution with prescribed burning given clear evidence of negative interactions with bushfire. They identify the need for continued monitoring and greater incorporation of biodiversity responses in addition to life and property into fire planning. 

The authors present an important example and model of collaboration across many institutions and organisations to assemble data and evidence that genuinely progresses understanding and provides important management implications for fire as global heating accelerates. 

The rapidly changing and deteriorating climate and environment we are now living in was painfully obvious during Australia’s 2019-20 megafires. Prof Driscoll led the largest ever study of fire impacts on Australian plants and animals, over 2,000 taxa. Our results show that areas that are frequently, extensively, and severely burnt are likely to have the greatest negative impacts on species, especially if these areas are outside conservation areas or impacted by drought.

The effects of fire on species were variable, and some even increased after fire. It’s increasingly clear however, that a global target to keep warming below 1.5C has almost certainly failed. A warmer world means megafires and severe impacts on people, communities and biodiversity will become the new ‘normal’ and a genuine existential threat.

With the 30% protected by 2030 conservation target and recent COP16 and COP29 meetings, now more than ever, we must take urgent action to divest from fossil fuels, accelerate the use of renewables, and expand protection for biodiversity within flammable landscapes.

This study is a valuable contribution to biodiversity conservation, particularly for fire-dependent ecosystems in Australia that are increasingly threatened by extreme weather conditions, such as prolonged droughts and dry seasons. Such conditions can easily lead to more frequent and intense wildfires with a larger geographic extent creating challenging environments for species survival.

This research is notable for examining all key parameters that shape fire regimes in these ecosystems, considering both the beneficial and detrimental impacts of wildfires on plant and animal habitats, as well as the effects of shifts in fire patterns. An important aspect of this study is its focus on previously underexplored factors, such as the influence of pre-fire drought—an element that played a significant role in the 2019-20 Australian megafire.

This study underscores the need for future research to develop databases of critical habitat variables. For instance, many native fauna species rely on tree hollows in both live and dead trees for shelter, so tracking these habitat features will enable a better effective assessment of wildfire impacts.

To support biodiversity and enhance fire management, this study advocates for actions by policymakers, including:

• Supporting patch-mosaic burning practices, as traditionally conducted by Indigenous communities through prescribed burning
• Utilising modern geospatial techniques to create detailed fuel distribution maps
• Expanding the coverage of national and state forests.

These measures will help mitigate the adverse effects of wildfires and foster resilience in Australian ecosystems.

The work by Driscoll et al. is an excellent summary of fire effects on biodiversity following the 2019-2020 Black Summer fires. The work highlights the impacts of extensive, high severity wildfire on a wide range of fauna, with the effects in rainforests and wet eucalypt forests being particularly pronounced.

Interestingly, the authors acknowledge that prescribed burning is a poor strategy for protecting vulnerable areas from subsequent burning. This suggests the need to rethink strategies to tackle the increasing threats to ecosystems and to biodiversity associated with wildfire. Clearly, a serious attempt to deal with the massive and pervasive problem of climate change is becoming increasingly urgent.

By looking at a huge number of species and sites affected by the ten million hectare Black Summer fires, this important research confirms that prescribed burning more than every ten years promotes more fire, and harms many species, native mammals in particular. This adds to the evidence for reducing prescribed fire frequency and leaving some areas long-unburnt for conservation. Reducing fire frequency is becoming even more important as the climate heats further.

National Park management sometimes gets the blame for bushfires, but this study shows clearly that species in National Parks were actually shielded from the most extreme effects of wildfire. In National Parks the natural vegetation and shelter such as large logs and hollows keep animals safer. I think this is a stunning result. This is a previously unappreciated way that National Parks can buy native animals and plants more time as fires increase under climate change.

The fossil record shows us that rapid warming events, like the one we are living through today, lead to increased intensity and frequency of kill mechanisms, like coral bleaching, droughts and, yes, wildfires. In other words, it’s becoming clear that one-off events are not usually enough to cause widespread species losses. However, the real killer is when the events come back bigger and badder than ever, before a species has had time to recover from the last one. The present research paper clearly supports this ‘burn and return’ model of extinction.

Because extinction is forever, it is an absolute tragedy when a species is lost. But a more insidious effect of repeated extreme events, like the Australian ‘Black Summer’ megafires of 2019–2020, is the permanent change in the character of the ecosystem. The fossils show us that previously dominant groups become the ecological underdogs, or wiped out entirely.

After repeated wildfires, dense, highly productive tropical wetlands can give way to dry, low-productivity scrublands. This decrease in ‘productivity’—total plant growth rate across an ecosystem—typically puts enormous pressure on animals by reducing their food and habitats. So, it is essential that our diversity hotspots, like tropical rainforests and wetlands, are kept wet and fire free.

The study of Australia’s recent megafires shows that Australians have to rethink our understanding and relationship with our natural heritage and the place of fire in our landscapes.

We knew that the 2019-2020 fires were devastating for wildlife and conservation and now we know that climate change, drought and our management of fire in the landscape are combining to intensify the damage that megafires can have. We have to align our policies to our values and follow through on our commitments on climate change, nature conservation and ecological restoration.