Fire and weeds in the Top End

Parts of northern Australia’s valuable landscape have been transformed by weeds and changed fire patterns. Coupled with land clearing for agricultural development, this has impacted significantly on ecological, social and cultural assets.

One example is the Northern Territory’s greater Darwin region and Daly River catchment, where areas of the tropical savanna have been invaded by weeds that threaten native plants and animals and impede access to parts of the landscape. Some weeds also carry high fuel loads, ultimately leading to more intense fires.

Invasion by grassy weeds and the resulting changes in fire regimes has the ability to significantly alter ecosystem processes and may eventually lead to ecosystem failure. However, our current understanding about the combined impacts of these threats and the action needed to improve ecosystem function is limited.

This project is drawing on existing information about the impacts of land clearing, weed invasion and changes to fire patterns on the natural landscape. Researchers are collecting additional data and use collated information to model the likely scenarios of changes in ecosystem function over the next 30 years in the Darwin and Daly regions. This understanding is critical to land use planning and management to predict, and hopefully prevent, ecosystem failure as well as to improve fire safety for people and infrastructure.

  • Better planning and management practices based on an improved ability to predict catchment scale changes that may lead to ecosystem failure.
  • Assessment of the use of fire behaviour models and fire spread simulators for northern Australia.
  • Revised conceptual models of savanna transformation following invasion by invasive grasses.
  • Improved understanding of the impact of invasive grasses on ecosystems and how this relates to the severity of invasion and fire impacts.
  • Evidence-based advice on how to account for gamba grass-invaded savanna in the Federal Government’s Carbon Farming Initiative’s Savanna Burning Methodology.

The research is taking place in the greater Darwin region and Daly River catchment in the Northern Territory.

Daly River catchment map

July 2020

Invasive gamba grass is transforming Australia’s northern savannas, replacing native species with a dense stand of highly flammable grass that burns up to eight times the intensity of native grasses. NESP research is helping the rangers at Mary River National Park in the Northern Territory turn this invasion around.

The project is being led by Dr Natalie Rossiter-Rachor from Charles Darwin University and Associate Professor Samantha Setterfield from The University of Western Australia. The project team is working with Bushfires NT.

Natalie Rossiter-Rachor, Charles Darwin University
[email protected]
(08) 8946 6469

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  • Mary River ranger among recovering trees in previously gamba-infested landscape. Photo NESP Northern Hub.
  • Tree death from gamba invasion and subsequent fires (aerial), photo NESP Northern Hub.
  • Recovering native savanna in Mary River National Park, photo NESP Northern Hub.
  • Person standing in front of tall stand of gamba. Photo NESP Northern Hub.
  • Gamba grass fire. Photo Sam Setterfield.
  • Measuring gamba grass fuel loads, photo Fiona Freestone.
  • Collecting soil samples, photo Daisy Lippiatt.
  • Tree death after gamba grass fire, photo Natalie Rossiter-Rachor
  • Gamba grass tussocks, photo Michael Lawrence-Taylor
  • Checking seed germination, photo Natalie Rossiter-Rachor.
  • Gamba grass tussock
  • Gamba grass tussocks, photo Michael Lawrence-Taylor