The war against wallabies using GPS, drones and dogs
They may seem cute and cuddly, but Dama Wallabies are just the opposite.
Threatening marsupials are officially classified as “unwanted organisms” under the Biosafety Act.
“We have had wallabies in the Rotorua area for over 100 years now,” said Dale Williams, biosecurity manager for the Bay of Plenty Regional Council.
“They were first released on Kawau Island in the Hauraki Gulf in the 1870s. Around 1912, someone brought them to the Bay of Plenty and freed them. They have since been released. dispersed and they now cover over 200,000 hectares. “
This is bad news for our forests and the native birds that call them home.
“Wallabies graze mammals,” Williams said.
“They are very careful about eating our native forest seedlings. And our native forests have not evolved – few plants have defense mechanisms like quills or chemicals, so wallabies can eliminate a whole host of these. native seedlings, stopping them becoming mature trees.
“Over time, the range of species in the forest will decrease, so there will be less diversity. Some of these species targeted by wallabies are also the food species of our birds. These are the ones that have the berries or the leaves which are particularly appetizing to birds too.
“The forests adjacent to the Rotorua lakes have been badly affected and this was becoming evident even in the 1970s. We have been trying to find a way to deal with this situation for decades. We’re really trying to stop the population expanding more than they currently are, ”Williams said.
Overall, the geography of the bay has done a good job of slowing the spread, with rivers being a major obstacle to dispersal.
“A wallaby won’t go into the water by choice,” said Williams. “Some rivers, like the Kaituna River, have been an effective barrier, the Tarawera River to an extent. But if you look at the streams in the Mamaku Ranges, they all point to the Waikato. So slowly but surely those -Here the animals scatter in the Waikato. “
Dama wallabies have also been found at Rocky Cutting Road in Welcome Bay.
But thanks to a $ 27.4 million grant from the government’s Jobs for Nature program, various tools are now being used to combat the spread.
“Dogs have been around for hundreds of years, old technology!” said Guillaume. “This is a very good monitoring tool. The dog and handler can cover an area fairly quickly and give us good feedback on presence or absence – ‘we have a wallaby there’ or ‘no’ , it looks like they haven’t made it to that place yet ‘. “
While the dogs are on the prowl, the dog handlers watch for anything the wallaby leaves behind such as footprints, fur, and droppings.
Dog handler Guus Knopers says the additional funding has given his canine team a welcome boost.
“It has increased our numbers by at least double if not triple,” he said. “We have trained several dogs throughout the certification process and are now starting to pair them with the new handlers.
“They have a muzzle because we could be working in areas where there are very endangered bird species, land birds.”
Once the dogs spot signs of a wallaby, GPS coordinates are recorded and cameras are set up.
“They’re really good at telling us if we have a breeding population because you’ll see a photo of a big wallaby, a young wallaby, maybe two in one picture,” Williams said.
There’s another high-tech tool available to the team: drones with thermal cameras to spot wallabies at night.
“The drone gives you real-time information,” Williams said. “They can understand that there are three wallabies out there, five there and it works great. Using the three tools together, we have a really good idea of the extent of the population before we do the check. . “
With additional funding and new technology, Williams said the goal now is eradication.
“You have to have that as your goal. There’s an old adage, ‘if you don’t aim for nothing, this is what you will get.
“I think eradication is a realistic goal. We will know in five or 10 years whether it is achievable with our current tools.”
Produced with funding from NZ on Air.