THE results of one of the world’s largest fire
experiments, conducted in Kakadu National Park over an eight-year
period, show that fire managers in northern Australia are on the
right track, but an overly high frequency of fires is of
concern.
The Kapalga Fire Experiment was established by CSIRO because
fire is such an important part of the northern Australian
environment, with more than 30 million hectares burnt annually.
Although fire is a major part of life in the north, CSIRO ecologist
Dr Alan Andersen said, the long-term effects on biodiversity are
not well understood. Conservation managers need this information to
help them do their job.
The Kapalga experiment covered 250 square kilometres, and tested
four major fire regimes common in the Top End. The results showed
that much of savanna biota is remarkably resilient to fire.
However, a significant number of plants and animals are seriously
affected by burning each year. Many of these species are affected
more by whether or not fire occurs, rather than by how intense the
fire is. This suggests that savanna biodiversity would benefit from
improved management of fire frequency.
“Much of northern Australia is burnt each year,”
said Dr Andersen. “However, more consideration needs to be
given to how frequently fires occur. Our results show that
biodiversity is optimised if substantial areas of savanna are only
burnt once every three to five years.”
Current rates of burning in many parts of the Top End are
substantially above this, with fire frequencies tending towards
between one and two years.
“At Kapalga we were able for the first time to look at the
effects of fire on the whole ecosystem. The experiment involved
researchers from universities and other organisations, as well as
CSIRO, covering topics including fire behaviour, nutrient cycling,
hydrology and stream dynamics, vegetation, insects and spiders, and
all vertebrate groups,” he said.
Parks Australia North, which manages Kakadu, provided valuable
support for the experiment. The agency’s head, Peter
Wellings, said land managers and scientists all agree that fire
needs to be actively managed in the Top End.
“The question is not ‘should the country be
burnt?’ but ‘when and where?’,” he said.
“Kapalga’s results are not just important for Kakadu,
but for all Top End land managers.”
