future is in islanders' hands
by Tim Higham,
Kiwis are the most unlikely birds: Pinocchio-beak, Lomu-legs and a Keira
Knightley breast. I watched one on Motutapu recently, blinking, whiskers
twitching, taking in the helicopter-assisted adjustment from the
Coromandel, among the first to be returned to the island.
Who is behind such a moment, when news
cameras whir, children gasp and hairs on the backs of necks stand on
end? Literally thousands of people: political champions, business
partners, supportive iwi, careful managers, technical experts, tireless
workers, volunteer crews and supportive public – early adopters, main
streamers and last-on-boarders … Successes like this take time and
Motutapu’s kiwis are the latest reason to celebrate in a chain of island
In the 1970s there was no shortage of
nay-saying when junior lecturers John Craig and Neil Mitchell suggested
pest-plagued, sun-addled Tiritiri Matangi might become a forested
wildlife sanctuary. Today it supplies and exchanges native birds and
reptiles with a growing network of copycat and sister projects: Motuihe,
Motuora, Hauturu/ Little Barrier, Motukorea/ Browns, Rakino,
Rangitoto-Motutapu, Mokohinau, Tawharanui, Waitakere’s Ark in the Park
as well as islands and sanctuaries outside the Hauraki Gulf.
The restoration of islands is a bright
spot in an otherwise underwhelming story of environmental management
around the Hauraki Gulf Marine Park.
The Hauraki Gulf Forum’s 2011 State of our
Gulf assessment compiled monitoring information from land and fishery
management agencies and found most indicators showed ongoing decline or
levels associated with poor environmental condition. It is easy to look
out over the Gulf on a fine day, marvel at its natural beauty, unaware
of the changes and stressors wrought upon it.
Around Barrier it can be hard to find a
decent patch of legal-sized paua. I’ve heard it suggested they don’t
grow that big in these waters (perhaps justifying the taking of a few
smaller ones?) Rather, remaining paua are likely to be relic populations
(there are a few carefully hidden ones well over 125 cm around) and the
attitude is known as using a sliding baseline: each generation sees as
normal a reduced environmental state without memory of, or reference to,
Others might be surprised that hapuku –
now caught at carefully-guarded GPS co-ordinates in deep-water – was
once a top predator of inshore reefs. But left alone for a decent while,
paua and hapuku would find their way back to their original densities
Like at the Leigh marine reserve, where
large snapper are nine times more abundant than surrounding areas, and
at Tawharanui where the reserve’s 3.5 km of reefs hold as many crayfish
as 40 km stretches either side. Kelp forest and associated reef
communities are markedly healthier in the reserves as the abundance and
size of top predators keeps species like kina in a natural equilibrium.
To the west of Great Barrier the habitat
type which once covered much of the Firth of Thames and Tamaki Strait
has all but disappeared. Dense beds of sub-tidal green-lipped mussels
were dredged until uneconomic in a 30-year period until 1967. Then the
last few beds were heavily poached through the 1970s to sell in pub
With them went one of the most productive
ecosystems of the Gulf. Mussel reefs provide shelter for algae, small
invertebrates and juvenile fish. Densities of fish are 10 times higher
than surrounding sandy areas. And at their prime mussel reefs could have
filtered the entire water of the Firth in a day compared to the two
years it would take the remaining patches today.
Mussel spat has not been able to
re-establish on the bare substrates left after dredging and the muddy
sediments accumulating from land run-off. The cycle of natural
regeneration has changed, and passed a tipping point. The beds won’t
return now without active intervention.
Shifting baselines and tipping points are
important in understanding Great Barrier Island’s future.
The big picture first: Since their
arrival, humans have eliminated nearly half of New Zealand’s original
native bird species and, of the remainder, a large proportion are
Great Barrier has fared a little better
than most places, as its isolation meant some of the country’s most
voracious predators, like Norway rats, stoats and possums, were
excluded. But ship rats and cats did make it and have thrived.
Populations of birds, reptiles and insects that may be taken for granted
and viewed as common, are slowly, sometimes suddenly, less abundant:
kokako, whiteheads and riflemen are the most recent disappearances from
the island; bitterns, kakariki and tomtits are noticeably scarce; and
kaka, black petrels and wood pigeons are likely to be next.
At a recent seminar organized by the
Hauraki Gulf Forum the Prime Minister’s Science Advisor Sir Peter
Gluckman suggested we focus resources on preserving whole ecosystems.
“We need to get cleverer at looking at species before they reach their
Windy Hill and Glenfern Sanctuary enable
comparison between environments where predatory pressures vary from
intense to light. Where rodents, cats and pigs are kept at very low
densities, plants such as nikau and puriri seedlings, insects such as
weta, and birds like wood pigeons, kaka and tui are more abundant.
Re-introduced New Zealand robins can survive and breed successfully.
Outside the sanctuaries, the island is
noticeably quieter, and will become more so, as rats and cats work their
way through fauna at a rate faster than it can reproduce.
Once a population is pushed past a tipping
point it is lost from the island and won’t come back, unless through
active intervention (assuming a sanctuary exists elsewhere) and to an
environment where the stressors are contained.
Glenfern and Windy Hill sanctuaries are
proof of the possible. Critical to their success has been the regular
application of predator control methods, including trapping and a range
of toxic baits – carefully monitored for environmental impacts – and, in
the case of Glenfern, a predator-proof fence. But surrounded by cat and
rat infested land they have to deal with constant re-invasion and
re-application of the control methods. If you want a battleground
analogy think the Balkans conflict compared to the Battle of Britain.
Rather than being called upon to fight incursions from multiple sides,
an island with a moat proved more successful in defense.
If eradication was done once, everywhere,
there would be no need for ongoing application of costly control
measures and, for some people, concern about environmental effects.
By using a range of techniques Glenfern
and Windy Hill are building knowledge about whether a complementary mix
and match approach might be possible at broader scale, according to
environmental factors and community preferences.
Another lesson has been that economic
benefits accrue for investments in enhancement. Windy Hill has created
18 jobs over the last 13 years and currently provides eight jobs for
islanders, while guided walks and accommodation support Glenfern’s
A whole island as a lived in, worked in
sanctuary, with regenerating and thriving native flora and fauna, is
likely to create similar opportunities in biodiversity and tourism
At the Hauraki Gulf Marine Park scale, a
recent stock-take of economic activity commissioned by the Hauraki Gulf
Forum showed tourism and marine recreational activity providing the
lion’s share of earnings and jobs. These sectors also have much greater
capacity to grow than extractive uses, suggesting enhancement and
economic development are broadly compatible and identifying the
potential for an industry cluster with environment at the heart of its
Great Barrier Island can gain from a
“blue-green” economic growth agenda, increasingly recognized and
promoted in business, local and central government circles. The Great
Barrier Local Board’s recent commitment to community consultation about
the island’s environmental future is timely and significant.
Like the cast of thousands that made
Motutapu a place of celebration and wonder, there’s a similar
opportunity for the people of Great Barrier to think carefully and find