Attitude is important. When I envisage a
possible future for pest management in New Zealand, a quote attributed
to the German Goethe sets the right tone: “Whatever you can do or dream
you can, begin it. Boldness has genius, power and magic in it.” The key
words here are “dream” and “bold”, since we began pest management long
Right from its beginnings, ingenuity – a
travelling companion of boldness – has featured as well. Back in 1894,
Richard Henry travelled to Resolution Island, the world’s first island
sanctuary, as its newly appointed curator and caretaker. During his long
sojourn there, Henry became a global pioneer of translocation techniques
for rare endangered birds, particularly kiwi and kakapo. He ultimately
left Resolution, despondent at the arrival of stoats that would undo his
best efforts to provide a safe offshore island for endangered species,
but his innovative techniques still inspire.
The Richard Henry self-resetting kill
trap for rats,
oppossums and stoats has been developed by DOC.
Crown Copyright Department of
Te Papa Atawai Photo: Herb Christophers
Fast forward 70 years to 1964 and another
defining bold moment in pest management. At the time, the conventional
approach to protecting species was not particularly interventionist.
Some writings by influential scientists and managers seemed more
resigned to losing rare bird species than taking dramatic action to save
them. And the ability of mammalian predators, especially rats and
stoats, to eliminate populations or even species was not fully
In 1964, a plague of rats threatened three
rare bird species and a native bat that lived on Big South Cape, an
island off Stewart Island (Rakiura). A few Wildlife Service field
officers insisted that only urgent action to relocate these endangered
species could save them. Others argued that this was unnecessary; the
rat numbers would eventually go down. Nonetheless, a bold rescue
operation went ahead and 36 rare South Island saddlebacks were
successfully transferred to local rat-free islands. Translocations of
the other two rare species, Stead’s bush wren and the local snipe, did
not succeed and rats quickly killed off all the saddlebacks, bush wren,
snipe and the unique native greater short-tailed bat left on Big South
Cape. These three extinctions, and the dramatic rescue of the
saddleback, was a wake-up call for conservation managers everywhere.
Hard lessons were learned: introduced
predators can drive native species to extinction; off-shore islands can
be essential refuges for vulnerable species; translocations can work;
scientific authorities don’t always know best. Ridding offshore islands
of pests to provide havens for other species then became one of the
successful tools for conservation management.
One thing conservationists should do more
often, in my opinion, is take the time to reflect on what their
campaigns and actions have achieved – while acknowledging the part
played by researchers and innovative management practices. When we do
so, we can list some remarkable achievements since the 60s. For example:
rat eradiation from Breaksea Island (170ha) in 1988 – then a world-first
for large islands; the ingenuity of Don Merton and colleagues in
rescuing the black robin from extinction; eradicating possums and rats
from Kapiti Island (1965ha); dozens of eradications of mice, stoats,
rats, deer, feral cats and possums from islands, followed by numerous
successful transfers of birds, lizards and insects.
Arid Island (Rakitu) some 5kms off the
NE Barrier Coastline
is being considered for eradication of rats. Photo: IslandStay
In 2001, little more than a decade after
clearing rats off Breaksea Island, DOC took on the bold dream of
eradicating rats from Campbell Island, a massive 11,300ha sub-Antarctic
island. Two years in the planning, and faced with novel logistical and
technical challenges, the eradication was declared a success in 2005.
Other countries now contemplate clearing large islands of pests that had
previously been thought impossible. Sir David Bellamy has said: “New
Zealand is the only country which has turned pest eradication into an
export industry.” This reputation owes much to the innovative research
and can-do attitude that has turned visions into reality.
Then people boldly asked “If we can do it
on offshore islands, can we do it on the mainland?” This led to research
during the 1990s into the feasibility of managing pests at low enough
numbers in isolated areas of forest to benefit threatened species. The
mainland islands model was born. Unfenced mainland islands were followed
by private and innovative initiatives creating islands of habitat
surrounded by predator-proof fences from which pests were removed.
Conservationists can take pride in their successful efforts to eliminate
possums and other predators from Bushy Park and protect the increased
kereru and kaka populations with a predator-proof fence around the whole
area. However, high capital and maintenance costs limit the options for
predator-proof fences. They are not a viable option for the larger
landscapes over which ecosystems need to be managed and should not be
held up as alternatives to the large-scale issues.
What might further research and
technological advances in pest control allow us to boldly dream for
tomorrow’s conservation goals? Pest management options fall into three
basic classes – physical, chemical and biological. There is a new
generation of physical “smart traps” (Forest & Bird magazine, November
2010) that shows how far trap technology has advanced from the days of
the cruel Lanes Ace leg trap. Cheaper, humane, resetting kill-traps for
rats, stoats and possums are being tested now. With further investment
and development, they could revolutionise pest management by drastically
cutting the labour costs that trapping currently requires.
The chemical control option means using
poisons. The current stand-out issue here is the aerial distribution of
1080 to control several different mammalian pests. In the Past 30 years
there have been many technological improvements in bait manufacture,
guidance systems for pilots and improved sowing buckets to spread baits.
Field research has improved our understanding of how to increase the
acceptability of poisons, including 1080, to possums, rabbits, rats and
The outcome of all these incremental
improvements is best demonstrated by comparing how much 1080 bait was
used in aerial operations in the 1970s compared with today. Success
rates have improved to over 95 percent reductions in possum, rat and
stoat numbers while the amount of bait used has dropped from 25kg of
bait per hectare to 2-3kg per hectare. Spreading 2kg of pellet baits
over a hectare is equivalent to dropping four baits on a doubles tennis
court. With few baits per unit area, the risks of by-kill of non-target
species is now much lower than before.
Despite the high development and registration costs, work continues on
new toxins. One acts on red blood cells to cut their ability to carry
oxygen around the body. Early research results suggest it may be an
effective and humane toxin for stoat control. The most acceptable toxin
is one that is cheap, humane and species specific – and effective. We do
not have it yet, but it is a goal worth pursuing.
I am less optimistic about biological
controls being developed for the nasty pest trio of possums, rats and
stoats – at least in the foreseeable future. After many millions of
dollars, research on a biological control for possums has been stopped.
Biological control did help to significantly reduce rabbit numbers after
the illegal introduction of rabbit calicivirus. However, the
effectiveness of the virus has weakened over time and those farmers who
did little to complement it with conventional rabbit control now face
high rabbit numbers again. The lesson is not to expect research to
deliver a quick-fix silver bullet for our mammalian pest problems.
With further major improvements in traps
and toxins, what bold visions might we dream and what barriers could get
in our way? First, let’s think about even bigger islands from which
pests might be eradicated. At 28,500ha, Great Barrier Island has rats,
mice and feral cats, but no possums or mustelids. In a decade or two we
may have a super, self-setting rodent trap that could do the job.
Perhaps a combination of next-generation anti-coagulants and rolling
lines of traps along the island could achieve what now seems impossible.
The whitehead (Mohoua albacilla) - high
list of species to re-introduce to GBI.
Crown Copyright Department of Conservation
Te Papa Atawai Photo: Joseph Fraser
After clearing the North Island’s largest
offshore island of predators, a bigger challenge would be clearing
Stewart Island of predators. Imagine the translocation options that
would open up. Rakiura National Park would be home to the many surplus
kakapo from Codfish Island, along with lots of kokako, kaka and other
threatened species from other managed areas. Before long, the restored
dawn chorus and local increase in kiwi numbers would draw visitors to
Stewart Island from New Zealand and beyond.
Study a map of New Zealand, and its
geography suggests other audacious visions. How about using the urban
sprawl and squeezed neck of Auckland as a barrier and clear the
farmlands and forests from there to Cape Reinga of possums and stoats?
Northland is home to important kiwi populations and most of these are on
private, not conservation lands. Given the threats to wild kiwi
populations throughout New Zealand, this could provide safe areas at a
new order of magnitude for our national bird to thrive. Might Coromandel
Peninsula and the bulge of Taranaki, both important areas for
biodiversity, also be capable of effective “isolation” followed by
intensive knockdown or eradication of major pests?
Thinking about pest management only in an
island context is too limiting for the larger systemic issues we face in
New Zealand. First, most of our threatened biodiversity is in places
where the island treatment is not feasible or is prohibitively expensive
at present. Second, islands are “out there”, whereas we live “in here”,
where competing political and social influences and attitudes are more
complex. It is how we change our thinking about pest management “in
here” that will support or stunt bold dreams for the future. I suggest
this is the fundamentally important transformation we need, supported by
ongoing technical advances that will be needed to realise such dreams.
Several relevant factors underpin this
transformation and they may change in ways that make it possible. These
• Shifts in ecological thinking
• Changes in values and engagement
• New governance arrangements
• Maori-Pakeha dialogues
Ecological science has undergone an
important shift in emphasis and perspective in the past two decades. The
earlier belief that ecosystems naturally tend towards conditions of
equilibrium has shifted to understanding ecosystems as dynamic systems,
capable of rapid and unexpected changes. This is particularly true in
New Zealand with our geological instabilities, exposure to cyclones,
droughts and floods, now overlaid with the diverse impacts of introduced
plants and animals.
Management and biodiversity policies based
on equilibrium assumptions can be inappropriate for dynamic and
unpredictable systems. Understanding dynamic systems requires a greater
knowledge of ecological processes and how key species respond to change.
For example, discovering that kereru play a major role in the dispersal
of forest seeds and therefore in the regeneration of forest ecosystems
means their management is as relevant to maintaining the overall health
of forests as it is about conserving a species. Since our primary
production industries and tourism ultimately rely on the health of our
biodiversity, greater research effort into understanding these ecosystem
dynamics to improve their management would be a smart investment.
As David Young describes in Our Islands,
Our Selves, attitudes to conservation change over time, reflecting and
shaping broader social values. Walter Buller’s Eurocentric and
pessimistic views on ‘inferior’ native species and their likely demise
have long since been marginalised. New Zealanders increasingly value
indigenous plants and animals. The rapid growth in the number of
community groups dedicated to looking after local reserves, protecting
breeding sites, starting restoration projects, restoring wetlands or
opposing environmentally destructive practices attests to this.
Changing social values towards native
biodiversity are occurring at a time when traditional arrangements of
hierarchical government are being questioned and contested. The dominant
model of top-down, expert-driven, government-led policies and practices
is increasingly challenged across areas as diverse as agriculture,
transport, energy, health, climate change and conservation management.
These global trends reflect the increasing complexity of
socio-environmental problems and the unprecedented ability of civil
society to access and share knowledge and information, something
governments used to control and regulate to a far greater extent than
Kokako (Here being radio transmitter
banded) have been successfully introduced into a rat-managed area in the
Crown Copyright Department of Conservation
Te Papa Atawai Photo: Herb Christophers
As a consequence, new approaches to
governance are being tried that are more flexible, adaptive and
responsive to stakeholder values and interests than is possible under
older hierarchical structures. These developments are particularly
relevant for adaptive management approaches which, in turn, are
appropriate for studying dynamic systems. The success of adaptive
management requires new ways for management agencies, stakeholders,
interest groups and researchers to work together, including on pest
control, such as deer or possum issues. By doing so, different voices
can be heard and reflected in management goals. As the late Geoff Park
has written: “Good management will require public dialogue as much as
expert opinion because the definition of goals and development of
scientific understanding is an interactive and experimental process.”
Management staff, scientists and
communities have already shown that these new approaches can succeed.
Even the contentious issue of aerial use of 1080 has been worked through
in some places with the input of all parties to arrive at acceptable
solutions. If the will is there on all sides, solutions can be found.
New Zealanders, whether for or against 1080, value their native forests
and birdlife and support pest control. They only disagree on the
methods. With agreement on the goal, surely the rest is just detail?
I have left the impact of Maori-Pakeha
dialogues to last, not because it is least important but because the
other influences I have discussed all provide the context within which
Maori-Pakeha dialogues on conservation, including pest management, are
best considered. In the opening article in this series (Forest & Bird,
November 2010), David Young proposed that Forest & Bird would need “to
step up to a new level of relationship with iwi and hapu”, noting that
the Waitangi Tribunal’s Wai 262 report on the claim on indigenous flora
and fauna would provide an opportunity to do so. This report is due out
this month and a constructive response will require more New Zealanders
than just Forest & Bird to step up.
I look forward to a dialogue on how Maori
spiritual and cultural values, as well as their holistic concepts, such
the principles of mauri, connectedness, ecological harmony, continuity
and reciprocity can inform the way we approach ecological studies and
pest management. A leading scholar, Mason Durie, has argued that these
principles can be measured quantitatively even though they are often
seen as spiritual. Durie also writes: “Essentially value is a function
of relationships …” Pakeha relationships with Aotearoa and its wildlife
will deepen as the centuries pass and therefore Pakeha values will
change along the way. We are ready for a dialogue that builds a better
understanding of the connections between Maori and Pakeha values because
that will provide a stronger basis for new governance arrangements and
partnerships with Maori for conservation and pest management. The Wai
262 report may provide the stimulus for this to happen, but we should be
planning it anyway.
Some may view these developments with
alarm. I see them as positive opportunities. In 2050, we should be able
to look back with pride on achievements since 2011: dramatic
improvements in control technologies that enabled eradication of pests
on a scale previously thought impossible; generous budgets to support
biodiversity research and management on public and private land by
governments that finally appreciated the economic sense of this as smart
investments; many new partnerships and co-management arrangements
between Maori, communities and agencies that are successfully managing
for biodiversity and minimal pest impacts; a deafening dawn chorus when
families greet the morning sun and renew their spirits in their local
forest, wherever that may be.
Wren Green researched possums for the
Forest Research Institute before joining the Department of Conservation
in 1987. He has been consulting since 1997 in areas including
biodiversity, biosecurity, sustainable development, science policy and