The frequency and location of prescribed burns must be rethought if Australia’s plants and animals are to be preserved, according to a study into biodiversity loss from the Black Summer fires.

Some 3 billion vertebrate animals are estimated to have died or been displaced by the fires on the East Coast alone.

But the severity of those losses depended largely on the fire history of the 10.3 million hectares burned, according to a new study. published in the journal Nature.

The study analyzed 62 datasets compiled by several universities and government departments containing 810,000 records of 2,200 plant and animal species in New South Wales, Victoria, Queensland, South Australia and Western Australia.

Researchers quantified the impact on biodiversity in areas burned following the Black Summer fires.

Ecosystems that experienced three or more fires in the 40 years preceding the 2019-2020 fire season had 87-93% greater negative impacts on biodiversity than areas that burned only once or not all during the same period.

Sites that burned less than 10 years after the Black Summer also had negative species impacts 70 percent higher than areas that had not burned in 20 years.

Six ecosystems were covered, but the study primarily focused on the alpine and subalpine areas of eastern Australia, where much of the data comes from.

While overall, Black Summer had a 55 percent negative impact on the amount of different species, 44 percent was positive.

The study’s lead author, Don Driscoll, a terrestrial ecologist at Deakin University, said some groups of animals, such as mammals, have seen particularly severe declines.

“There is also an increase in the number of wild predators, which are more effective hunters in these (burned) habitats.

“The dilemma is that our study shows that sites that burned frequently before fire experience much greater declines caused by fire.”

Joe Fontaine, a disturbance ecologist at Murdoch University who was not involved in the study, said it was clear that nature’s responses to fires became more extreme with past disturbances, such as burning. directed.

“The increase in fires in recent years, the increase in the consequences of drought and the reduction of protected areas are all elements associated with greater destabilization,” he said.

“This greater variance is concerning and is an indicator and pathway for ecosystem collapse. It has been documented in other contexts such as Great Barrier Reef coral bleaching.”

Dr Fontaine said the new study suggests a greater need to consider biodiversity risks when planning prescribed burns, but it should also be validated in areas other than the eastern part of the country. ‘Australia.

How much fire should we have?

The study suggests that intermediate intervals between fires, between 11 and 20 years, are those that least disrupt biodiversity. Long intervals between burns were also necessary to provide refuge for species.

Professor Driscoll said having unburned areas around a site that had been burned also limited the negative impacts of a fire on biodiversity.

He also noted that the study found slightly fewer negative impacts on biodiversity in nature reserves and national parks, but not on state forests which still include recreational and forestry uses.

The findings are at odds with current practices aimed at reducing bushfire risks to people and property, which vary across the country but include shorter intervals of six and eight years.

Professor Driscoll said he believed the study had implications for fire management.

“Current management is to frequently reduce fuel emissions to limit the effect of large fires.

“By burning forests frequently, we prepare them for a significant fall during the next fire.”

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As an alternative to frequent prescribed burning, other than for the protection of lives and property, Professor Driscoll said government fire management agencies should invest more urgently in rapid fire suppression.

This would involve investing more resources into quickly detecting and suppressing fires before they become too large.

Professor Driscoll said he believed there were signs that agencies were accepting changes to how they managed biodiversity risks, with intense fires expected to become more frequent due to climate change.

“(There is) the famous example of the efforts in the Wollemi Pine, installing sprinkler systems and deliberately putting out fires when they hit those ecosystems,” he said.

What do the firefighters think?

An Australian Capital Territory Government spokesperson said the study provided meaningful data that was valid for consideration in fire management planning in the Territory.

The spokesperson said the government recognized the threat of megafires and was considering further research into biodiversity as it developed its new strategic bushfire management plan.

“Over recent years, the ACT Government has invested in strengthening ecological and biodiversity considerations in fire management activities, including fire preparedness, prevention and suppression operations.

“Protecting biodiversity during bushfires is a key priority and is best achieved in an integrated manner, alongside the priority of protecting life and property.”

A spokesperson for the Washington State Department of Biodiversity Conservation and Attractions said prescribed burning was his state’s primary mitigation measure.

“From a biodiversity perspective, prescribed burning is undertaken to maintain a range of wildlife habitat types.

“Prescribed burns occur under more favorable conditions than intense summer bushfires, providing more opportunities for animals to move safely into areas of unburned vegetation and for diverse plant species to regenerate.”

The spokesperson said WA already had a fleet of aerial spotters in place for the fire season and was keeping an eye on new detection technology.

A spokesperson for the NSW Department of Climate Change, Energy, Environment and Water said it was already responding to some of the paper’s key findings.

“The document also recommends using indigenous fire knowledge to encourage rapid fire suppression,” they said.

“This is a new area that NSW Government scientists are investigating with Indigenous cultural scientists.”

The South African and Victorian governments have also been contacted for comment.