Toad-proof fences around man-made dams could stop the spread of the toxic pests in some arid parts of Australia, scientists say.
In the first study of its kind, researchers from the University of NSW examined the long-term control of cane toads and found that blocking their water source would kill them in large numbers.
Lead author Mike Letnic said dams built for livestock attracted toads and had vastly increased the areas that the poisonous creatures could invade.
"Cane toads need water to survive and we have previously shown they use the dams as refuges in the hot, dry periods," he said.
"They enter the water during the day to cool down and rehydrate.
"When the rainy period returns, they move on from these dry season refuges into new territory."
Associate Professor Letnic said it explained why cane toads were so successful as invasive species.
During the study, researchers made small fences from shade cloth around three dams in the Victoria River region of the Northern Territory and maintained them for a year.
Toads could not jump over the fences or burrow underneath, so they died en masse.
Their numbers remained low for another year while there were up to 100 times more toads living at the unfenced dams used as controls.
"By excluding toads from dams, we converted their invasion refuges into ecological traps and thwarted their spread," Assoc Prof Letnic said.
The researchers suggested pastoralists and wildlife agencies in semi-arid and arid regions could fence out toads at dams or replace dams with tanks.
"If conducted strategically, excluding toads from man-made water sources could effectively control their populations across large areas of Australia and relieve the impacts that cane toads are having on native predators and dung beetles," Assoc Prof Letnic said.
