Graeme Loh is the first to admit he is more ''exterminator''
He is the Department of Conservation (Doc) ranger who
oversees one of the country's newest reserves, a prominent
and ancient limestone outcrop at Gards Rd, between Duntroon
He said his main focus was to eradicate an aggressive exotic
invader - boxthorn - which threatened to appropriate this
''People don't realise how bad a weed it is and how difficult
it is to remove.''
Mr Loh has held several working bees at the site to eradicate
the boxthorn. Heavily kitted out in protective gear,
volunteers poison, hack, cut, roll and start over again to
annihilate the viciously thorny scrub and its determined
Boxthorn was most effective at keeping lions away from
cattle, Mr Loh said.
There was a tone of exasperation as he wondered aloud how
many of the beasts had threatened stock in this valley.
Its thorns could puncture a tyre and cattle were desperately
afraid of it, he said.
Critically, at the site it competed with the rare natives for
space and water and its roots cracked the soft limestone
''The take-home message is if you have boxthorn on your
property, destroy it.''
Mr Loh was instrumental in arranging Doc's acquisition, with
$200,000 from the Nature Heritage Fund, of the 20ha block
from farmers David and Lorraine Parker and it was formally
handed over in February.
Many rare plants had been discovered growing at the site and
the purchase meant they could continue to be conserved and
It is home to the rare native broom Carmichaelia Hollowayi,
one of only three places in New Zealand where it grows wild.
The cliffs also provide refuge for prostrate kowhai (Sophora
prostrata), the rare native cress Lepidium sisymbrioides, and
Raoulia monroi, a mat daisy.
It would be fair to say the rare collection is distinguished
by being small, dull and insignificant; some look little
different from the wire-netting now protecting them.
It turns out being unassuming was a particularly important
strategy, as a dull and divaricating habit provided good
protection from the browsing birdlife which once wandered the
''The prostrate kowhai are an excellent example of signature
adaptations to bird browsing - they have a high tensile
strength; you can't pull them apart easily. They have small
leaves and dull leaves because birds have good colour
Mr Loh is optimistic about progress to recreate the former
place in time.
In only a few months, the ''primary knockdown'' of boxthorn
was well advanced and there had been ''pretty good progress''
on the regrowth.
A fully grown (upright) kowhai, possibly 100 years old, has
emerged out of the efforts of the past few working bees and
numerous seedlings have since come away, which have been
protected and will be propagated.
Water containers drip-feed the seedlings as a dry spell in
the valley begins to take hold.
Other steps like rabbit-proofing have been taken to protect
the precious treasures.
But solving one problem can lead to others - Mr Loh is still
searching for a suitable way to keep grasses down, now sheep
do not graze the area.
Geologically, these bluffs were only a small part of the
bigger picture and shared relationships with other limestone
outcrops through South Canterbury, Mr Loh said.
But as a remnant of ancient New Zealand they offered a window
to a ''dramatic and active landscape'' and were one of the
few clues as to what the past had been like, he said.
There was proof they had been used by Maori for shelter,
although any possible rock art may have eroded away because
of the softness of the limestone.
But the outcrop had locked in the history and secrets of
ancient sea beds in layers of rock and soils - testament to
tumultuous events which shaped and lifted them to where they
sit now, high above the cultivated Waitaki River valley.
The cliffs and gravels are home to dolphin, whale and penguin
fossils, some of which are 25 million years old.
Mr Loh points to lines at the base of the bluffs where layers
of sheep manure give way to layers of moa dung, blurred lines
between past and present.
These days the bluffs appear to be essentially frost-free -
something Mr Loh is testing - and this possibly had
contributed to the survival of some of the rarer plants, he
Eventually, there would be more propagation and planting out
to boost the plant populations.
But that role would fall to others of his team, he said.
''My role in ecosystem is to kill things, the exterminator
... I'm not the expert at nurturing.''
By the end of the year he hopes the reserve, which is already
open to the public, will have signage, a walkway, and car