Using animal and insect species to control pest type animals or insects is not a new idea and, as proven through history, carries substantial risks to the native flora and fauna into whose environment they are introduced. This can be seen clearly in the Cane Toad debacle of Australia.
Following the successful introduction of the South American Cane Toad (Bufo Marinus) to the sugar cane plantations of Puerto Rico to control crop devouring grubs, word spread quickly. By 1930 cane toads were global jet setters finding homes around the world to protect crops, or so the people of Queensland Australia thought….
In 1935 101 toads arrived in Queensland before being bred in captivity and subsequently release to hunt and kill the cane beetles along Australia’s North East coast.
Australia has had a long history of inadvertently introducing ‘wrecking ball’ species as pets and livestock, foxes, rabbits and cats. However, the meteoric rise and dramatic effect the cane toad’s introduction has had upon the native flora and fauna cannot be overstated.
Breeding in huge numbers the cane toads gorged on other local wildlife and began spreading rapidly across the country, some estimates put the current figure at around 1.5 billion.
Cane toads fitted into ‘niche theory’ which dictates how suited an animal species is to an area based upon its environment and interaction with other species. Research found that cane toads filled a wide fundamental niche in Australia, as opposed to the narrow tightly defined role in their native South America. This has led to the supremely adaptable cane toads rapidly colonising the landscape, largely due to their lack of natural predators.
While in South America cane toads co-evolved alongside other toads and other species which developed to prey upon the cane toad, these predatory restraints are absent in Australia.
A large gland on the toads shoulder is loaded with deadly cardiac toxins which has been blamed for the deaths of native animals such as snakes, quolls, crocodiles, goannas who, thinking the cane toad as native, attach them as prey and subsequently die from the toxins.
Researchers have employed ‘taste-aversion strategies’ which include feeding sausages of cane toad meat to native predators to make them ill, but not die, a large-scale trial of this approach will take place in Western Australia soon.
However, so far, the scientific and community effort has failed to stop their advance. Working together pastoralists, rangers and environmental groups are trying to restrict the toads access to bodies of water, after 10 days without water the toads will die, they aim to create a waterless ‘firebreak’ to halt the spread. We can only hope that this is a success.
The story of the Cane Toad in Australia is a harrowing example of the risks hand in hand with the introduction of a non-native species for the purposes of pest control.
And the moral of the story...to deal with pests, stick with Pest Expert.