Four-year old English springer spaniel Pip and five-year-old jagdterrier Mawhai have spent over a year training to sniff out kauri dieback, in the hope the Auckland council biosecurity team can stop it spreading to islands off the gulf and the parts of the Waitakere Ranges, which have so far been spared.
The dogs were chosen for their age and experience, and have transformed what used to be a six-week process to test and confirm the disease into a matter of seconds.
Kerryn Johnson, a biosecurity adviser for Auckland council, said the dogs were the first in the world able to sniff out kauri dieback, which can be spread by as little as a pinhead of soil on the sole of a hiker’s boot or an animal’s paw.
There is as no known cure for the disease and the trees are facing “functional extinction”, the ministry of primary industries says, despite a government working group set up in 2018 to tackle its spread.
“We’ve now got two dogs who we are really confident testing soil samples taken from the bush and sniffing out kauri dieback disease,” said Johnson. “We’re still working out how sensitive they are, what kind of threshold the pathogen has to be in the soil sample for the dog to pick it up … we’re still figuring how out best to deploy them.”
Dogs are also used by the Department of Conservation to sniff out introduced pests such as rats, mice and stoats, and also some forms of introduced vegetation.
Dogs noses are thought to be 40 times more sensitive than those of humans, and they are able to learn to ignore other pathogens and scents – planted by their trainers in an attempt to distract and mislead them – when rewarded solely for sniffing out kauri dieback.
At this stage the dogs would not be used in the forest as the risk of spreading the disease was too high, Johnson said.
In 2018 the conservation minister Eugenie Sage told the Guardian that kauri dieback was “devastating” for New Zealand’s unique flora and fauna. Since then, however, the disease has continued to spread, despite numerous closures of national parks and walking tracks, as well as rahui [bans] placed on infected areas by Māori.
Local animals such as pigs and hunting dogs, as well as hikers, are thought to be responsible for the continued spread of the disease.