Gone in a puff of smoke: 52,000 sq km of ‘long unburnt’ Australian habitat has vanished in 40 years

• The pattern of fire most commonly experienced within an ecosystem is known as the fire regime.
• We wanted to find out how Australian fire regimes are changing and what this means for biodiversity.
• Read more:
  Research reveals fire is pushing 88% of Australia's threatened land mammals closer to extinction

Uncovering long-term changes

• However, evidence of how fire regimes are shifting within both threatened species’ ranges and protected areas is scarce, particularly at the national scale and over long periods.
• To address this gap, we compiled maps of bushfires and prescribed burns in southern Australia from 1980 to 2021.

More fire putting wildlife at risk

• Meanwhile, areas of recently burnt vegetation (5 years or less since the most recent fire) are growing.
• On average, the percentage of long unburnt vegetation within reserves declined from 61% to 36% over the four decades we studied.
• Going from about 42,000 sq km to about 64,000 sq km in total, which is an increase of 22,000 square kilometres.

Which areas have seen the biggest changes?

• This pattern was most prominent in southeastern Australia, including the Kosciuszko and Alpine national parks.
• Feral horses are finishing the job

  In these locations, dry years with low rainfall can make abundant vegetation more flammable.

• These conditions contribute to high fire risk across very large areas, as observed in the 2019–20 fire season.

What does this mean for Australia’s wildlife?

• Indigenous land management, including cultural burning, is one approach that holds promise in reducing the incidence of large fires while providing fire for those species that need it.
• We can also help wildlife become more resilient to shifting fire regimes by reducing other pressures such as invasive predators.
• Our findings underscore the increased need for management strategies that conserve threatened species in an increasingly fiery future.

• William Geary is affiliated with the Victorian Department of Energy, Environment and Climate Action.
• Dale Nimmo receives funding from the Australian Research Council, the Department of Biodiversity Conservation and Attractions, and the Department of Energy, Environment and Climate Action.