A Parks officer lighting up a fire in a tropical savanna fire impact experiment

A Parks officer lighting a fire as part of the Kapalga fire experiment.

Kapalga fire experiment

The landscape-scale Kapalga Fire Experiment examined the ecological effects of four contemporary fire regimes, as a basis for enhanced conservation management in northern Australia.

  • 1 August 2007 | Updated 14 October 2011

Background

One of the world’s largest fire experiments, the Kapalga Fire Experiment, was carried out in Kakadu National Park by scientists from CSIRO’s Tropical Savannas group between 1990 and 1994.

Savanna vegetation is commonly regarded as highly resilient to fire, regenerating very quickly during the following wet season. Before the experiment, little was known about the longer term effects of fire on:

  • vegetation
  • biodiversity
  • ecological processes, such as nutrient cycling and energy flow.

In particular, there was the question of whether declining populations of some species of birds and small mammals were due to changes in fire regimes.

The experiment

The Kapalga Fire Experiment's main features were:

  • it was conducted at the landscape scale, with experimental units comprising 15-20 km2 catchments
  • a range of fire regimes occurring in the region were tested
  • the experiment was replicated, with each fire regime repeated at least three times.

The project involved collaboration between:

  • CSIRO
  • Charles Darwin University, Darwin, Northern Territory, Australia
  • the University of Wollongong, New South Wales, Australia
  • Parks Australia (managers of Kakadu).
    Before the Kapalga fire experiment, little was known about the longer term effects of fire on vegetation, biodiversity and ecological processes such as nutrient cycling and energy flow.

It covered a wide range of topics including:

  • fire behaviour
  • atmospheric chemistry
  • nutrient cycling
  • hydrology and stream dynamics
  • vegetation
  • arthropods
  • all vertebrate groups.

Experimental fire regimes

Four fire regimes were tested at Kapalga:

  1. early - annual fires were lit early each dry season. This is the most common contemporary management practice in conservation areas such as Kakadu National Park.
  2. progressive - annual fires were lit progressively through the dry season as country dries out. This was considered to approximate traditional Aboriginal burning practices.
  3. late - annual fires were lit late in the dry season. This represents the type of fires commonly occurring in the region as uncontrolled wildfires.
  4. unburnt - no fires were lit.

What the results show

Two recurring results emerged:

  • much of the savanna biota showed little or no response to even the most extreme fire regimes, and is therefore highly resilient to fire. Exceptions were riparian vegetation and associated stream biota, and small mammals.
Much of the savanna biota showed little or no response at all, and is therefore highly resilient to fire.
  • where fire had a marked effect, the contrast was often between burnt versus unburnt areas, rather than high versus low intensity fires. This indicates that fire frequency is particularly important, more so than previously recognised.

Implications for management

The resilience of savanna biota in relation to fire is good news for conservation managers, because it provides them with considerable flexibility. Across most of the savanna, one ‘mistake’ with fire is unlikely to cause long-term or irreversible damage.

However, the results also show that optimum plant recruitment and biodiversity requires substantial areas of savanna to be burnt once every three to five years. This can be achieved by reducing the overall area burnt each year, or by more strategically targeting the areas to be burnt in any year.

Outcomes

The main outcomes of these experiments were:

  • better and valuable understanding of the effect of fire on plants and animals in the Top End on the Northern Territory with results outlined in a series of Fire facts sheets
  • the Kapalga Fire Experiment data was used by Dr Garry Cook and Dr Adam Liedloff, in collaboration with the Tropical Savannas CRC, to develop the Flames simulation model to investigate the effects of fire and rainfall on savanna tree dynamics
  • the experiment indicated the need for further investigation into the effects of fire frequency time-since-fire on ecological function and conservation management in northern Australia
  • a research and education program has been started to give greater predictive understanding and capacity to model response to fire in the longer term - see Burning for biodiversity in the Top End .

Scientific team

The principal CSIRO scientists working on the Kapalga Fire Experiment were:

  • Dr Alan Andersen
  • Dr Dick Braithwaite
  • Dr Garry Cook
  • Dr Laurie Corbett
  • Dr Pat Werner
  • Dr Dick Williams.

Read about Fire ecology and management in the rangelands and savannas.

  • Andersen AN, Cook GD, Williams RJ. (eds). 2003. Fire in Tropical Savannas: The Kapalga Experiment. Springer-Verlag, New York, NY, USA.