Yellow crazy ant eradication begins in Arnhem Land
“This little ant will destroy our culture, our land, our life, so we need to kill it now.”
Balupalu Yunupingu, Dhimurru senior ranger, north-east Arnhem Land
The spread of one of the world's worst ant pests in the Northern Territory is being halted.
The Yellow Crazy ant (Anoplolepis gracilipes) is recognised by the Global Invasive Species Programme as one of the world's worst invaders. It has infested more than 350 hectares over a 25,000 km2 area in remote north-east Arnhem Land, and represents a major environmental and economic threat to northern Australia.
A major eradication program has commenced involving Dhimurru Aboriginal Land Management Corporation, local Aboriginal communities, Alcan Gove, the Northern Territory Government, the Northern Land Council and CSIRO. The program is receiving funding support from the Natural Heritage Trust and the Indigenous Land Corporation.
CSIRO ecologist Dr Ben Hoffmann said Yellow Crazy ants formed multi-queened 'supercolonies' in which ants occurred at extremely high densities over large areas.
“The density of foraging worker ants in supercolonies is amazing, reaching around 1000 per square metre or 79 million per hectare of bush,” he said.
Dr Hoffmann said the ants had a significant impact on biodiversity in these areas, and seriously disrupted ecological processes. They can cause outbreaks of sap-sucking insects, which in turn are able to kill vegetation.
“This makes them a serious pest of agriculture as well as the natural environment,” he said.
The Yellow Crazy ant is believed to have been accidentally introduced to the area during the Second World War. Dhimurru Aboriginal Land Management Corporation senior ranger, Djawa Yunupingu, said the ant had so far been found in 70 locations around human settlements, along creeks and in disturbed areas in eastern Arnhem Land.
They nest in all kinds of materials, from potting mix to packaging, making it very easy for them to be accidentally transported by people.
Northern Land Council Land Management Facilitator, Mark Ashley, said the ants had the capacity to spread from Broome in Western Australia across to Queensland.
“It is important that we eradicate this species now before it becomes a major economic and environmental pest throughout northern Australia,” he said.
A clear example of this ant's devastating abilities is its impact on Christmas Island. Yellow Crazy ants have killed an estimated 15-20 million red land crabs since Crazy ant supercolonies were first reported in 1989, a decline of 30 per cent of the crab population. This has led to major changes in the island's rainforest ecosystem, and is threatening a range of rare and endangered species on the island.
The ant will be controlled by specialised bait that has minimal environmental impacts. Project milestones for the first year include the treatment of 75 per cent of the total area of all infestations.
Further information:
Dr Ben Hoffmann – CSIRO, 08 8944 8432, mobile 0418 820 718
Mr Balupalu Yunupingu – Dhimurru, 08 89873992
Mr Mark Ashley – Northern Land Council, 08 89205100
Mrs Suzanne Hunter – Alcan Gove, 08 89875234
Media assistance:
Geraldine Capp – CSIRO 02 6276 6409, mobile 0438 498 509
Barry Clarke – Northern Land Council, 08 8920 5114, mobile 0438 854 4049
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