Changing Planet

Predator Free New Zealand: Conservation Country

New Zealand was one of the last places on earth to be colonised by humans, only about 1,000 years ago. Using some fairly exciting new tools, such as paleoecology, scientists can now make pretty clear statements about what was here before humans arrived, and what happened after humans arrived. What happened was nothing out of the ordinary, just major transformation of habitats, in this case through altered fire regimes, and the introduction of many new species, some of which have gone on to become invasive. Ever since, New Zealand has lived the legacy of these impacts.

Predator Free New Zealand (Logo by Tim James)

The introduction of mammalian predators to the islands of New Zealand caused the same impacts they had on all other islands – drastic reduction, it not outright extinction, of naïve native species. New Zealand responded boldly by pioneering the eradication of these predators from islands, larger and larger with each passing decade. The eradication of these predators is not about whether they are native or not, but about the damage they cause. These efforts are not about winding the clock back to a time before New Zealand was colonised, but about saving what is left of original New Zealand today.

Predator management in New Zealand today
Predator management in New Zealand today (Map by Eagle Technology)

Could we reach zero invasive predators on the main islands of New Zealand? In the May issue of BioScience, with colleagues from Landcare Research, we discuss the biological research, technological advances, social capacity and enabling policy that would be required to theoretically eradicate introduced mammalian predators from the entirety of New Zealand. Is this even possible? Perhaps as much as flying to Mars isn’t today, but will be one day. Is this economical? It turns out very much so, when casting a fine lens over the accountant’s national balancing book. The entirety of New Zealand could become the first conservation country. We also believe other nations with substantial island estate should at least consider aiming for the 10% offshore island area predator-free which New Zealand has today, so the unique species found on those islands can remain safe until we can eradicate introduced predators from larger islands, or perhaps even fly them to Mars.

Incidentally, the PFNZ trust is running a competition at the moment to update the above map of predator management in New Zealand.

Read All Posts by James Russell

Conservation biologist Dr. James Russell works throughout the world on remote islands and other sites to provide conservation solutions by applying a combination of scientific methods. Follow James on National Geographic voices for regular updates on his own work or other exciting developments in island conservation.
  • Peter Russell

    We’ll have to tackle invasive plants a lot more seriously before we can seriously call NZ a conservation country.

  • tom

    Am curious how it would in practice. Move up the country with a ‘line of control’? Or blitz everything everywhere in a sustained manner over a really long period?

    Also, in terms of animal invasives, which could be targeted (am assuming popular hunting and pet species like cats, dogs, pigs and deer would have to be excluded)?

  • Since not everywhere could be done at the exact same time it would likely involve a ‘line of control/rolling front’ as proposed by ZIP.

    The PFNZ concept discussed here and supported by the Trust is for mice, 3 rat species, 3 mustelid species and possums, which all are considered unwanted in NZ (but possibly wanted elsewhere:

  • Blair

    And 1080 is one of these tools! Yes?
    Predator free is a pipe dream after all what about New Zealands own native predators? Morepork,bats, Falcons snails amongst others!

  • 1080 is one of the tools today, but we couldn’t predict what the tools in the future might be, but the journal article emphasises that new tools would have to be developed.

    The journal article and post here also state that the ‘predator free’ only refers to 8 introduced mammalian predators.

  • andy blick

    this is nothing more than an academic exercise and not reality based. In order to succeed extreme cruelty and animal torture has to be applied on a mass scale. Propaganda is the main tool being used to vilify so-called “pest ‘ animals such as cats, rats possums and stoats. Once labelled as pests the public accepts they can be poisoned slowly to death using terrible toxins such as 1080. To achieve this goal NZ would have to be saturated in poison applied at much higher application rates than currently used. Already several landowners, I know of, are creating animal sanctuaries which will nullify any attempts at eradication. The whole exercise demonstrates an archaic view of nature still persists in NZs scientific circles. Anyone withan understanding of the natural world would never contemplate such horrific action.

  • Your comments remind me about this previous post I wrote at the start of the year

  • Blair

    They might need to change the name to Introduced predator free then!
    Tell me how 1080 only targets introduced mammalian predators again.
    Tell again how these introduced mammalian predators will be removed from populated areas or how these predators will be stopped from spilling over into the forests!

  • Poison risk is a function of toxicity and exposure. By delivering poisons in a form which isn’t attractive to non-mammals (e.g. in green cereal baits or bait stations) then you can specifically target introduced mammals.

    How we eradicate introduced mammalian predators from populated areas and prevent spillover is definitely one of the areas identified for further work across biology, technology and social science.

  • Bob

    James Russell,What long term affects would be seen with the removal of these mice rat,mustelid, and possum species?

  • I’ve recently been thinking about the impacts of these predators in a productivity/energetics/biomass framework. They are currently ‘harvesting’ every piece of surplus from our ecosystems (including species). I imagine one thing we’ll see is natural productivity explode after their removal, like we have on predator-free islands. More plants, more animals, more productivity, which is good for everyone and thing.

  • bob

    James,As this seem to be your field, i was looking for a more comprehensive answer than ”more plants more animals”. As Bob Brookie in A living New Zealand Forest ,says [ We know little of the effects of removing these predators] Personally i have no training in this field but different evolution pathways [ both flora and fauna] surely will be created by this removal?

  • bob

    James my apoligys for getting your name wrong

  • Bob – The Brockie book from 1992 is a fantastic summary of the history of scientific research in the Orongorongo valley, and since then we’ve learnt a lot more about the effects of removing these predators, particularly with regards to indirect effects.

    When they were introduced, they changed the evolutionary pathway of many native species – many to extinction. Similarly with their removal we would expect to see changes in evolutionary trajectories, hopefully towards the path our native species were originally on. Overall I personally hope we can restore more natural evolutionary landscapes.

  • Blair

    Ah ok!
    So those Kea poisoned while developing a repellent that still doesn’t work don’t count?
    How about secondary poisoning of natives? Once these unattractive baits are ingested by another animal say a rat how are the Morepork,Weka Falcon stopped from ingesting this poisoned mouse?

  • Blair – no one is denying that kea and other (native) animals sometimes consume poison, which is certainly unintentional during pest control operations. However, most people also recognise that those same kea and other native animals are dying at even higher rates from the predators themselves. If we do nothing, those species will go extinct, but <1% of NZers believe doing nothing is an option with regards to pest control.

  • Paul Martinson

    Wider education in regard to NZ’s unique (surviving)species and there inability to cope with invasive species is really important here. ‘Predator free NZ’ must surely be possible with the cooperation of the majority of NZers but many organizations are a potential threat to this based on their past rhetoric. SPCA for one, make frequent statements implying we need an environment full of cats and rats in order to have any ‘natural balance’…or ‘cycle of life’ This nonsense must be refuted at every occasion.

  • A review also came out this week on cat impacts on wildlife in New Zealand

  • bob

    James i was looking for more info on this,can you point me to any studies done on long term effects on NZ native ecosystems of pest predator species removal ? Would you say the first factors to influence native bird declines,were canopy change and habitat destruction? And could you expand on how its possible to redirect native evolution back to anything approximating the original pathways?

  • Bob – these two studies are the best most recent examples:
    Note the second one also shows that predators don’t controls rodents in New Zealand.

    I would not say the first factors to affect native bird declines were canopy change and habitat destruction. Native birds can exist in modified habitat, including pine forest, farmland and urban areas (e.g. kereru, bellbirds, tui, fantails). On the contrary, we see that during the invasion of Big South Cape Island in the 1960s, an unmodified island of native forest, after rats arrived, 3 species went globally extinct and many more locally extinct. Habitat modification and canopy change played no role in this.

    With regards to re-directing towards natural pathways, the original pathway would be well approximated by removing the major stresses to bird evolution. i.e. introduced predatory mammals. By removing these mammals (e.g. as done on islands) we can assume the birds have a more natural evolutionary environment. e.g.

  • flow in

    This is insanity.
    NZ needs to take off its myopic ‘kill everything’ mindset and look at NZ as a part of a global ecosystem. Work WITH evolution, not against it. Lets export our threatened species, find a place in the world where they thrive, rather than destroy ecosystems in a misguided attempt to hold back time.

  • bob williamson

    James thanks for the links,I will get copies of both.I have to admit to being a little doubtful re all native birds being able to adapt to a loss of 70% of there natural environment,Pasture does not provide the many and varied food sources found amongst our native bush ,The pine forests we have now are a relatively recent occurrence in New Zealand.I have a rural property with areas of bush,also have worked in rural New Zealand all my working life,And certainly in EBOP even the Kereru,Bellbirds,Fantails are most often seen in these bush areas .The Big South Cape Island and the three species that went extinct when rats appeared ,although canopy change or habitat destruction may not have played a part,can we really assume this played out in an identical way over the whole country? We had, now extinct bird predators,and still have bird predators.The canopy change such as in places like [Te Urewera] to a large percentage of Tawa is not what our native birds evolved along side of,As this is not the natural environment they evolved in, will this not create very different pathways?

  • I don’t really see how importing foreign predators is considered ‘evolution’, there is nothing natural about it. And with rats on over 80% of the world’s island groups, there is nowhere else to move these species, they are endangered on island ecosystems the world over from the same mistaken predator introductions. Luckily we have the ability to remove these predators from islands now. As stated in the post this has nothing to do with wanting to turn back time.

  • pete lusk

    I cant see how this predator Free NZ concept can work when we have so little knowledge of how ecosystems. We’ve had 1080 drops for 40 yrs in Buller and still have plenty of possums, mice, rats, stoats, deer and goats but we are losing the kea and rock wren to this eco-poison. Its time for a reassessment, not more poisons.

  • I think PFNZ is exactly that reassessment which will look at how we can move from a model of perpetual pest control to permanent eradication, which has been so successful on NZ islands.

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