The poisonous toad, 'Bufo marinus', has increased it's invasion of northern Australia. The toad, an introduced species, is toxic to Australian animals; even canetoad tadpoles kill native frogs with a poisonous slime. Researchers tracking the expansion of canetoad populations use 'listening posts' in creeks and swamps; when the calls of native frogs disappear, they know the canetoad has arrived.

New research has discovered that the canetoad has evolved into a longer-legged variety and has increased the pace of invasion, moving north at up to 60 km each year, a five-fold increase. The canetoad is also adapting to cooler southern climates.

Australian native animals do not recognise canetoads as a threat and they die when trying to eat them. Tiger snakes have been found dead with a canetoads in their mouths, the snake is dead before it can swallow. In Kakadu national Park, a World heritage listed area, a small marsupial predator, the quoll, has been decimated. Government organisations are now trapping and moving quolls to islands which they hope will act as 'arks' to preserve the species.

Kakadu National Park is famous for its river and swamp ecosystems. Every animal in Kakadu that preys on frogs is at risk from canetoads. Goanna lizards have already started to disappear. The list goes on; animals like the quoll, crocs, native frogs, turtles, fish and birds will be affected.

If you have ever wanted to experience the pristine wilds of Kakadu, do it now - before the ecosystem collapses and becomes a swamp dominated by the roar of mating canetoads.

‘The disaster looks set to turn into an ecological nightmare because of the negative effects invasive species can have on native ecosystems; over many generations, rates of invasion will be accelerated owing to rapid adaptive change in the invader.’ – From: Nature 439, 803 (16 February 2006) For the full story visit:  http://www.nature.com/news/2006/060213/full/060213-4.html