Importing Australia’s chlamydia bears
Are koalas climate change refugees deserving of a warm Kiwi welcome or a potential environmental risk to already struggling ecosystems?
They’re cute, leaf-eating and have lost vast swathes of habitat in their home country, but is offering up New Zealand’s eucalypt plantations as a home-away-from-home for koala a wise idea?
It’s a cuddlier version of the image of New Zealand being a billionaire's bolt-hole. Are our forests, with their lack of predators for large mammals, a conservation estate for the endangered species of other countries?
The Koala Relocation Society, a previously unheard of group, without publicly available contact details, has launched a petition asking Prime Minister Jacinda Ardern to introduce koalas to New Zealand.
It’s attracted over 6000 signatures in a matter of days.
The petition, which incorrectly says koala are functionally extinct in Australia claims if koala were introduced to New Zealand they: “... would not compromise our local ecosystem, as koalas typically inhabit open eucalypt woodlands, and the leaves of these trees make up most of their diet.”
University of Auckland conservation biologist Dr James Russell isn’t so sure it can be guaranteed koala would stick to eating what we expect them to.
“That’s exactly what we thought with possums.”
Plonking a species in a new ecosystem can have unexpected and devastating effects.
“If possums in New Zealand behaved liked possums in Australia they would munch a few plants and be at low density. The problem was they got to New Zealand and suddenly started eating all of these other things they didn't eat in Australia because [those] didn't exist in Australia."
Russell said the bonanza of food in New Zealand had seen possum density explode to 10 to 20 times what they should be. Millions of dollars have been spent trying to eradicate them as they destroy our forests and impact agriculture with the bovine tuberculosis they carry.
Some koala have a retrovirus which affects their immune system in a similar way to AIDS making them more susceptible to infectious disease and cancers. Many have chlamydia. Russell isn’t sure whether chlamydia would be likely to spread to other mammals but said disease risk from and for koala would need careful consideration.
“It can go two ways, as well as much as the koala might behave in ways we don't expect, the koala might end up here and it might be terrible for them, they will end up dying.”
He also questions what would happen to koala introduced to New Zealand when the owners of the eucalyptus plantations decided it was harvest time.
Instead of turning parts of New Zealand into mini Australia Russell thinks environmental ethics should prevail.
“Rather than focus on what’s the individual effects - koalas are burning and that’s horrible - we should look at the bigger picture. Should New Zealand really be a conservation estate for Australia?”
The all lives matter movement
Sometimes described as “compassionate conservation” there is a movement which calls for animals to be treated as individuals and promotes the principle of ‘first-do-no-harm’. Peaceful co-existence is another principle of the movement.
The school of thought represents a butting of heads between animal welfare and conservation concerns and has come under criticism for not taking into account the damage invasive animals can do to other animals. Should we stop killing possums or rats because it’s cruel but allow them to eat kōkako chicks?
With climate change likely to raise suggestions of relocation in the future, Russell thinks the approach should be less individual and more holistic. Moving species somewhere safe, which is often well outside their native range, could set them up as an invasive species.
"It seems a poor solution when the fact is Australia should be stepping up its game and conserving its own species, not relying on other countries to do it for them."
Not just an offshore island translocation
Professor Phil Seddon, of the University of Otago's zoology department, has similar views to Russell.
“A lot of these things aren't overly numerous in their range countries. But the reason for that is because they have natural diseases, natural predators. If you move them away from those sort of natural regulations, then they may find local conditions to be fantastic and go crazy, which is what possums have done.”
He said shifting species to a new habitat they wouldn’t be able to get to without human help is not new and is used in New Zealand for conserving native species. An island hop is one thing, crossing the Tasman Sea is another.
“The bigger the move, the more the uncertainty, the greater the risk. Where you are jumping a big chunk of sea you really are moving into a very different system.”
One example of a smaller shift is the Tasmanian devil. The population in Tasmania was struggling with a disease which caused facial tumours. In the hope of ensuring a disease-free population a new population was established on Maria Island.
“This was quite a controversial thing to do.”
Other local species on the island were likely to be prey for Tasmanian devils said Seddon, but it was still felt the translocation was the right decision.
“They did create a good population and the devils are thriving there. There's evidence that they had had some impact on that local ecosystem though.”
The impacts include declines in little penguin, Cape Barren goose and short-tailed shearwater colonies.
Seddon thinks there are plenty of places left in Australia for koala without New Zealand needing to adopt them.
“It sounds like a bad idea to me.”
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