By Riley Schwengel
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| An Australian Possum: An Invasive Predator in NZ Credit: Brisbane City Council |
New
Zealand’s natural environment has a stellar reputation. Thanks to its starring roles in movies like
“The Lord of the Rings” and "The Lion, the Witch, and the Wardrobe" when people think of the
Pacific island nation, they think of crisp alpine mountains, breathtaking
waterfalls, and forests that look untouched by the ever encroaching shadow of
modernity. However, despite what
Hollywood blockbusters and instagram photos would have you believe, New
Zealand’s environment is under constant siege.
Before both
Europeans and Polynesians arrived on the two main islands that make up the
country of New Zealand, or Aoteroa depending on who your ancestors are, they
were evolutionarily isolated from all other landmasses for 50 million
years. The result of this isolation is a
unique but fragile ecosystem. Exploration, colonization, and globalization have effectively ended New
Zealand’s isolation and the fragile ecosystem that it holds is under attack from a bevy of
invasive species. According to the
Predator-Free New Zealand Trust: 81% of native New Zealand birds, 88% of native
reptiles, and 72% of freshwater fish are endangered. That’s a staggering statistic, especially
when you consider that only 30% of U.S. bird species are considered endangered,
20% of the world’s reptiles are endangered, and a 40% of U.S. freshwater fish
are endangered.
Some of the
main culprits behind the loss of native species are invasive predators. These are transplanted predators, including
cats, rats, stoats, and Australian possums, which have taken advantage of the
vulnerable New Zealand species and have decimated the populations. Science reported that an estimated
25 million native birds are killed every year by invasive predators.
This is not
a new problem; human kind has been dealing with the ramifications of moving
species hither and tither ever since we invented the boat. However, it has always seemed an uphill
battle and our efforts often are just buying time for more at risk species who
seem destined to fade away. Well, the New
Zealand Government no longer wants to play the part of Sisyphus and roll that boulder up a hill only to have it fall back down; it has
declared that by 2050 the two islands will be completely predator-free.
This is a
bold goal; one that has captured the media’s attention. In case you missed the news when it first came out, here’s
how New Zealand plans to kick out its invasive predators. The government's first step was to create an independent
company, Predator-Free New Zealand Limited (PFNZ), to spearhead the operation
and to raise money from private groups and companies. The Economist article on the subject makes
the point that this fundraising is a crucial part of the plan because, while
the government has already pledged 28 million NZD, the money comes with the
expectation that double what the taxpayers provide will be raised elsewhere.
The New Zealand Department of
Conservation (DOC) and PFNZ will run the large-scale removal operations and
allow other organizations to organize smaller efforts. There are some goals to be met before the
final 2050 endgame, for example by 2025 it is hoped that 20,000 hectares on the
two main islands will be predator-free and 1 million more hectares will be
undergoing predator suppression. All of
the goals that are currently specified can be found here. DOC has made the point
that they will be focusing on three types of predators: mustelids, possums, and
rats. It seems weird to exclaim
“Predator-Free New Zealand” and then not even mention some of the most damaging
predators such as cats and dogs, but that is an issue I would like to discuss
another time.
The Department of Conservation
estimates that the entire effort will cost around $3.7 billion, though some
other estimates put the cost as high as $9 billion.
There are a lot of challenges
facing the 2050 plan, first and foremost is that current techniques and
technologies will not be effective enough for the undertaking. While the usual methods of pressure-traps,
poisonous bait, and aerial drops have worked for small offshore islands and
private reserves that have been made predator-free, these simple methods will
not be enough to cleanse the entire nation of these invasive pests. Thus, a large percentage of the money raised will be spent on research
and development of new control and culling methods. Some of the new methods proposed are
self-setting traps, “invisible” barriers utilizing pheromones, and gene
manipulation. As Chris Allen with the
Federated Farmers group stated in an interview with Newstalk ZB, “We will need
really smart, innovative, mechanical means.
Whether there’s some chemicals or gene technologies that we can
use. We’ll need everything to make this
an achievable target…”
Another problem is merely that the
North and South Islands are the 14th and 12th largest
islands in the world respectively and both have a sizable variety of habitats
and geography . Different habitats require
different considerations and it is always imperative that the fragile native
environment of New Zealand not be damaged in the process. As Tony Martin from the University of Dundee
explained to Science Magazine, “Finding a way to eliminate every single bad guy
(rat, stoat, or possum) while leaving all the good guys untouched is going to
be the greatest challenge.”
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| A Stoat, Another Invasive Predator Credit: factzoo.com |
Even if the entire population of
invasive predators currently in New Zealand is extinguished, there is a flood
of animals constantly being brought into the country by boat. Mice and ship rats are some of the most
damaging predators in NZ and the same ships that bring in goods to the island
nation also bring scores of them as well.
Biosecurity will have to be tightened immensely if this plan is to
succeed.
Now the question on everyone’s mind
regarding the plan is very simple, can it be done? Well, people are split on that. Many say “yes” just because of how successful
previous efforts have been on off-shore islands. Based on the current growth-rate of
predator-free areas within the borders of New Zealand, the total eradication of
invasive predators on both the North and South Islands is feasible as reported
by the Economist. However it remains to
be seen if that growth will hit a ceiling when applied to an area as large as
an entire country. Others point to the
90% success rate that all previous removal efforts have had, but again the 2050
effort is of scale multitudes larger than any preceding undertaking.
Many people, scientists included,
are less optimistic. In a radio interview with Our Changing World from Radio New Zealand in 2015, Andrea Byrom
and John Parks from Landcare Research expressed doubts about the possibility of
a predator-free New Zealand. They
expressed that they did not believe that such a thing would be possible in
their lifetimes or even their children’s lifetimes. So, to those two, 2050 as a deadline seems to
be a bit of a stretch. The scientists
also expressed that getting rid of predators would not solve all of the
problems faced by native species, there is also the issue of habitat
connectivity and native species recovery.
The members of Landcare Research worry that the drive to expel predators
will result in the eggs all going in one metaphorical basket.
Over all, the Landcare researchers
believe that full eradication may not be the best method, as Andrea Byrom said,
“For some areas on the mainland we have to accept that full eradication is
never going to be achievable…I personally feel that we don’t have to go for
full eradication everywhere”. Instead
she believes that suppression and monitoring of predator populations may be
more cost effective and feasible in the long run.
So will this ambitious plan
work? That’s a hard question to answer
with all of the variables in place. From
all of the information I’ve gathered and the different viewpoints that have
spoken, I personally am still optimistic.
I think New Zealand can one day be predator-free if they do develop
innovative new techniques, are able to keep the program well funded, and are
able to keep the public invested in the cause.
However, I am not so sure that this will be done by 2050. This is a massive undertaking on a scale that
has never been attempted. I believe that
control projects may cover the entire country by 2050 but I do not actually
believe that New Zealand will be truly predator-free by that time. Personally, I believe that such an ambitious
deadline was really only set to capture headlines and garner support, which it
did successfully. The cause is a good
one and all should support this effort to protect one of the most unique
ecosystems on Earth, but we should be cautious about how feasible the deadlines
and promises made actually are.
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| A Kiwi, One of Many Native Animals Threatened by Invasive Predators Credit: kiwibird.com |
Strange Criticism
As I did research for this piece, I
came across many criticisms for New Zealand’s plan, but most were concerning
the realism of the methods employed. I
only found one source that was against the idea of invasive predator control
all together and I would like to reply to that specific critic.
The source in question was an
article from the Pittsburg Post-Gazette titled “Messing with Fauna: Be Leery of‘Predator-Free New Zealand’”. Weirdly,
the reason that this piece was against the expulsion of invasive predators was
that Communist China tried to do something kind of similar and failed. The article states, “New
Zealand should take note of China’s environmentally disastrous ‘Four Pests
Campaign’ launched during the darkest days of the Great Leap Forward from 1958
to 1962. Chairman Mao Zedong and the Communist regime initiated a quixotic
campaign to eliminate mosquitoes, flies, rats and sparrows from the Chinese
mainland. Mao called upon ordinary people in the world’s most populous country
to do their patriotic duty to kill the four pests upon sight”(Post-Gazette). The article then goes onto say that New
Zealand may very well be heralding a period of environmental collapse by
exterminating the invasive predators that reek havoc on their nation’s
ecosystem.
I’d
like to start with a simple statement that the writer of this piece obviously
does not realize; mainland China and New Zealand have vastly different
ecosystems contained within them. China
is attached to Eurasia, the largest continuous landmass on earth that contains
some of the most biodiverse regions on the planet, and New Zealand is two
islands that have been evolutionarily isolated for 50 million years. New Zealand is obviously a much more fragile
environment and just because the radical environmental policy of the Chinese
was a failure does not mean that a somewhat similar goal is not achievable in
New Zealand. I would also like to point
out that New Zealand is dedicating numerous resources to research and
development so that the extermination and expulsion is done effectively; they
are not urging mobs of citizens to go out and hack animals to death. I am a bit puzzled why the author of this
piece had any problem with the New Zealand program, but it is obvious that they
only read a headline and hurried to get a word in without learning more first.
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