Over half of Australian species decline following 2019-20 megafires: report
A new study from Deakin University has revealed that more than half of Australia’s animal and plant species suffered population declines as a result of the devastating 2019-2020 Black Summer bushfires. The research, published in Nature and compiled by over 100 scientists, assessed the impact of the fires on 1,380 species across the country and found that 55 percent of them experienced declines in abundance or distribution.
The Black Summer fires, which ravaged an estimated 24.3 million hectares of land, were among the most catastrophic in Australia’s history. The fires directly claimed 34 lives and caused hundreds of additional deaths due to smoke inhalation. The aftermath of the fires left vast areas of habitat destroyed, affecting ecosystems and wildlife across eastern Australia.
The study found that mammals were particularly vulnerable, with population declines averaging twice as severe as those seen in other animal groups. However, the research also highlighted a more nuanced picture, noting that 44 percent of species were found to be more common in areas that had been affected by the fires, suggesting some resilience among certain species.
The study calls attention to the role of prescribed burning, a practice commonly used in Australia before bushfire seasons to reduce fuel loads and mitigate wildfire risks. While prescribed burns are meant to reduce flammable materials, the research indicated that these controlled fires could exacerbate ecosystem damage, especially when they occur in areas that have already been impacted by large-scale wildfires.
According to the study, biodiversity impacts were significantly higher in areas that had experienced multiple fires in the past four decades. Regions that had been burned three or more times saw biodiversity losses up to 93 percent greater than areas that had experienced fewer fires. Moreover, areas that had burned within the previous 10 years saw 70 percent larger negative impacts compared to regions that had not burned for at least 20 years.
Researchers concluded that intermediate fire intervals—specifically between 11 and 20 years—caused the least disruption to biodiversity. These intervals allow for natural habitat recovery, providing refuges for wildlife and promoting the development of critical ecological features, such as tree hollows, which take years to form.
The findings are prompting calls for a reassessment of Australia’s current fuel-reduction strategies, urging for more evidence-based approaches to fire management that consider the long-term ecological consequences. As climate change continues to increase the frequency and severity of bushfires, the study emphasizes the need for adaptive strategies that balance fire prevention with biodiversity preservation.
