15 September 2004

Research conducted by Charles Darwin University on the impacts of Gamba grass will feature on this week’s ABC TV science program, Catalyst, to be broadcast on Thursday from 8pm.

“Gamba grass was brought in as an improved pasture for cattle grazing in northern Australia but when Gamba grass moves outside pastoral properties it can become a serious weed,” Dr Michael Douglas, Project Leader of the Exotic Grasses Group at the Charles Darwin University.

Charles Darwin University's Dr Michael Douglas being interviewed by Paul Willis from ABC's Catalyst

For the past six years, staff and students at Charles Darwin University have been working collaboratively with CSIRO, the NT government, Kakadu National Park, Department of Defence and the weed control industry to find out three things about Gamba grass.

• What helps it to spread, compete with native plants and establish in new areas?

• What impacts is it having on native vegetation, fire regimes and nutrient and water cycling?

• How can it be effectively controlled and managed in areas where it is not wanted.

“The results are worrying and clearly demonstrate the serious threat Gamba grass poses to the future of our tropical savannas,” Dr Douglas said.

“Gamba grass readily establishes across a wide range of habitats using more water and nutrients than native grasses. The taller and denser stands of Gamba grass provide a ready source of fuel for dry season fires which are much hotter than normal and can kill the native shrubs and trees, eventually leaving a landscape completely dominated by Gamba grass.

“These changes will have serious consequences for savanna biodiversity. Hotter Gamba grass fires are also emerging as a threat to properties in the rural area and are a real problem for the people who are called out to fight these fires.

“Although the future looks bleak, research into more effective control has recently begun and looks promising. Gamba grass can be controlled by herbicide and the seeds do not last long in the soil once the adult plants are removed. The strategic use of fire may also assist.

“But, with gamba grass still spreading in the NT and starting to take hold in north Queensland, the research team will focus future research on identifying areas at greatest risk of Gamba grass invasion and on developing better methods of containing it within the areas that it has been planted,” Dr Douglas explained.

The University’s team of researchers includes staff members Samantha Setterfield, Michael Douglas, Lindsay Hutley and Jane Barratt and students Trish Flores, Natalie Rossiter, Peter Clifton and Kristine Brooks. Working with the Tropical Savannas CRC has enabled the University’s team to develop strong collaborative links with weed scientists and managers across northern Australia.