Cane toads, an invasive and poisonous pest, have been wreaking havoc in Western Australia for the past 15 years. As their numbers continue to explode, scientists and authorities are taking drastic measures to slow their spread. The Toad Containment Zone, a 150-kilometer barrier, aims to disrupt the toads’ access to water and halt their invasion of the Pilbara region. This article explores the innovative strategies being employed to combat the cane toad crisis and protect the delicate ecosystem of Western Australia. Cane toad, Western Australia
Controlling the cane toad invasion in Western Australia, an innovative approach
Western Australia’s years-long battle with the invasive cane toad could be nearing a tipping point, following the discovery of about 10 juvenile amphibians in the Pilbara — more than 2,000km south where they were first sighted. The WA Government, researchers, Traditional Owners and pastoralists have combined to find a way of curing the stock while not leaving them stranded in the environment that made them unwell.
Key to this is the so-called Toad Containment Zone, a 150 km barrier that hopes to halt their onward spread by physically blocking adult cane toads from reaching water during the annual breeding season. The project includes the upgrading of its agricultural water infrastructure, and fencing off water sources to create a landscape-scale barrier that can prevent cane toads from crossing. The ‘toad break’ which spreads 600-kilometres and was around today along the Kimbolton Track from Sandstone Way to Broadhurst Road, would act like a firebreak, Professor Ben Phillips — a Western Australian Premier’s Science Fellow and cane toad professional — said.
A New Settler and Ecological Menace : The Cane Toad
Cane toads were imported from Central and South America in 1935 in unsuccessful bid to control epidemics of a beetle which was an enemy of sugar cane. Since that time, these incredibly adaptable amphibians have quickly spread and their populations have grown exponentially.
Why are cane toads so good at colonising? They are both generally long distance movers and reproduce at an absurdly high rate. A single female cane toad can lay a clump of eggs with up to 30,000 in one sitting and although most hatchlings (tadpoles) will be consumed by predators such as fish (native), some egg clumps are well protected. But that still wastes a big advantage in terms of increasing their population at an incredible speed. Cane toads also appear to be moving faster, too; their rate of spread has gone up from about 10 kilometers per year in the old days to 43 kilometers per year today — more than four times as fast as before.
Toad Free Zone — This is a key intervention in the protection of WA Ecosystems
The Toad Containment Zone is a key component of halting the cane toad front and protecting the Pilbara from that impact. Modelling by Professor Brown shows that 10 to 24 native species could be directly affected if action is not taken soon, with as much as 95 per cent of the Pilbara potentially occupied by cane toads.
The Toad Containment Zone is designed to take advantage of the fact that cane toads need water, and as they enter what ‘s essentially a bottleneck on their way through the slim corridor into the Pilbara. The project will improve agricultural water infrastructure and install toad proof fences around troughs so that cane toads cannot reach this essential resource, effectively creating a barrier beyond which they cannot pass. Professor Phillips appears confident in the approach, ‘this isn’t rocket science’, he said, ‘it’s plumbing’.
The ambitious project is backed by over a decade of scientific research and was one of the key recommendations from the 2019 Federal Senate Inquiry into controlling cane toads. In theory, the Toad Containment Zone has the potential to be a game-changer in Western Australia’s decades-long battle to defend its rare, isolated ecosystems from the biggest pest that it has ever faced.
