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Fierce exotic grass fires burn money in northern Australia

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Research has found that introduced tropical grasses spreading across northern Australia burn hotter and fiercer than native grasses, draining fire-fighting resources.

Charles Darwin University researcher Dr Samantha Setterfield, whose work was supported by Land & Water Australia, Charles Darwin University and the NT Department of Natural Resources, Environment & the Arts as part of the Australian Government Defeating the Weed Menace research program, named Gamba grass as one of the most serious of the invasive grasses found across the northern savannas.

Fighting a single Gamba grassfire can require more than twelve times the resources needed to fight a single native grass fire, because Gamba grass forms very dense stands up to four metres tall,” she said.

Low intensity native grass fires could typically be managed with minimal fire fighting equipment. In contrast, Gamba grass invasion has resulted in hotter fires occurring in residential areas, requiring helicopters and water bombing planes to protect people’s lives and properties. The negative economic impacts of managing Gamba grass fires will become increasingly evident as exotic grasses spread.”

The exotic grasses, including Gamba grass, were originally introduced as pasture grasses, selected for their resilience, high growth rates and high nutritional value compared to native grasses. These same characteristics make them successful weeds, and many have become problems outside pastoral land.

The research project aimed to develop tools to assess the economic implications of managing high biomass, invasive grasses, to be used in a risk management approach to weed control.

Dr Keith Ferdinands of the NT Weed Management Branch agrees that understanding the economic impact of exotic grass invasion and management is critical to developing strategic and cost-effective management responses.

Aside from the economic and risk management problems these grass species represent, there are also environmental repercussions. Australia’s savannas are unique among the world’s savannas: because of low human impact they remain relatively intact. The integrity of these savannas is being threatened by this range of high biomass, invasive tropical grasses.

In areas with Gamba grass, the research team found there was a 50% reduction in tree canopy cover over twelve years. The increased numbers of tree deaths appear to be a result of high-intensity Gamba grass fires. This dramatic change in the structure of savanna vegetation demonstrates the serious risk that Gamba grass poses to northern Australia’s unique savanna habitat.

The collaborative Charles Darwin University and NT Government research team is continuing to quantify the social, environmental and management costs of invasive grasses, to complete economic evaluations of different management approaches. This research will guide natural resource managers in the fight against the grassy weed invasion.

Contact: Nolani McColl, Land & Water Australia
(02) 6263 6000

This research is also outlined in newly published Thinking Bush 8. Photographs are available on request.
  


Citation

Land & Water Australia. 2009. Fierce exotic grass fires burn money in northern Australia. [Online] (Updated April 8th, 2009)
Available at: http://lwa.gov.au/node/3098 [Accessed Wednesday 23rd of October 2013 09:15:14 PM ].

id: 3098 / created: 08 April, 2009 / last updated: 08 April, 2009