New Zealand First says the government's plan for a 100% predator-free New Zealand by 2050 may be commendably motivated, but has the potential to derail into the worst unintentional ecological blunder of modern times.

Primary Industries and Outdoor Recreation Spokesperson Richard Prosser says while the plan may be noble in intent, many of the claims it is based on are unsubstantiated or supported by science that is equivocal.

'Some of the shortcomings of this proposal are obvious, while others are revealed as potential unintended consequences that the government has not even considered,” Mr Prosser says.

'Cats are not even mentioned, despite being an introduced predator and a major one at that – is this because the government knows that exterminating all cats from New Zealand is electorally impossible as well as physically impossible?

'Nobody wants our native species being decimated by introduced predators but it has to be remembered that our birds and lizards have coexisted alongside ferrets and stoats for more than 130 years, cats for 200 years, and rats for more than 800 years, yet we still have birds and lizards. The rat is the preferred food of the stoat, which only switches to preying on birds when rat populations are depleted.

'There is now an uneasy equilibrium, albeit an artificial one, out there that we run the risk of upsetting if the task of mammal control is not very carefully planned and executed.

'No human society in history has succeeded in exterminating the rat, and it is highly unlikely that we will be the first. The intention is so unrealistic as to be bordering on the irrational.

'Possums are primarily herbivores. Few studies exist that document the contribution of birds and eggs to the possum's diet, but those that do indicate bird material to be less than 0.5%. In some areas, thanks to diminished numbers of birds such as the kereru, possums may be the only agents capable of spreading large tree seeds.

'The myth that possums are the major cause of TB in cattle has been debunked by figures that the government itself has supplied in response to our questions. But we do know that poisoning operations aimed at possums result in the direct and indirect deaths of many endangered birds.

'It is telling that bird life flourishes around town fringes, where cats and rats and stoats abound but where aerial poisons are not used.

'New Zealand First wholeheartedly supports trapping initiatives and the development of new technologies, but we are very concerned that the government's approach will be to keep on increasing the use of poisons with systemic toxicity, threatening not only the species they claim to be trying to protect, but indeed our clean green image itself, in the pursuit of a plainly unattainable goal.

'Controlling pests down to sustainable levels, and increasing resourcing for larger, more numerous, and better-protected sanctuaries, is sensible and probably achievable. Imagining that we can exterminate cats and rats from the entirety of New Zealand is very probably neither of those things.

'Further imagining that a profit-driven private enterprise pest control company would successfully exterminate the very source of its income is naïve at best, and we have to question the government's motivation and indeed rationale in choosing this model,” says Mr Prosser.

SOURCE: Office of Richard Prosser