Gamba grass in the Top End

Morning all Yesterday I attended a meeting on tackling environmental issues in the Greater Darwin area, and all everybody talked about was gamba grass. This weed, imported as pasture for the beef industry, is native to the African savannah. Ungrazed it is a bulky grass reaching nearly 5 m. high. It is a transformer weed, meaning it transforms other vegetation communities to monocultures by carrying destructive fire, and by outcompeting native plants for water and nutrients and space and light. I first raised the issue of gamba grass as a threat to birds, at the launch of the second edition of Birds of Australia’s Top End in 2005. Since then I’ve written about this weed as a threat to both wildlife and to human beings. Yeet for years the NT Government, bowing to the wishes of graziers, took no action. The grass is now out of control throughout the Greater Darwin area. Yesterday a ranger at the nearby Litchfield Park said that this one weed covered 20% of Litchfield Park, and that in two decades it would cover nearly half the park. Dangerous wildfire fuelled by gamba grass is a big concern, and this ranger said it was only a matter of time before visitors died. This situation most likely exists in other parks as well. Consequently I suggest that birders visiting the Top End from June to November, be aware of the danger from fire. And if you’re going off road then hire a vehicle that uses diesel, not petrol. In my experience some tour operators and guides don’t recognise the threat, so check! I called for a cost-benefit analysis comparing the cost of gamba, mission, rats-tail and other weeds brought in as cattle pasture or as contaminants, against the so-called worth of the beef industry. I doubt it will happen – it’s a case of nationalising the problems and privatising the profit. However, graziers are now finding that gamba is more trouble than it is worth; firstly because it is so destructive to most native vegetation; secondly they can’t sell properties infested with the stuff; and thirdly because any property infested with gamba cannot be used for carbon offsets. Still, gamba has its supporters as a grazier pointed out gleefully the other day. Unfortunately there does not seem to be a way for consumers to access beef produced in a weed-free manner. According to academics and rangers present at this meeting feral cats are also out of control, and no one present could see any way of dealing with them. One ray of hope is to reduce the annual burning of forest and woodland which reduces ground cover making it easier for cats to hunt. However, because so much annual burning has occurred herbaceous under storey in much of these habitats has been replaced by fire-encouraging speargrass. Another ray of hope is that many landowners do their best to control both weeds and cats. However, it may not be enough to save several species. Denise Lawungkurr Goodfellow PO Box 71 Darwin River, NT, Australia 0841 043 8650 835 PhD candidate, Southern Cross University, Lismore, NSW. Founding Member: Ecotourism Australia Nominated by Earthfoot for Condé Nast’s International Ecotourism Award, 2004. With every introduction of a plant or animal that goes feral this continent becomes a little less unique, a little less Australian.