Alpine zones
Biodiversity
After an uphill grunt of an hour or so, most trampers are usually looking forward to a break in the forest and
rewarding views of the spectacular scenery below – it is what makes the steep climb worth the effort. But it is not
just the awe inspiring views back down to the valley floor which mark the sudden dramatic change in scenery.
Stepping above the tree line takes trampers into a completely new environment – the alpine zone.
There are three sub-zones that form the alpine zone, representing declining temperature and increasing exposure
with altitude above the tree line as well as different plant and animal life. The tree line cut-off occurs at different
heights depending on where you are in the country. It occurs about 900 metres in Southland and about 1450
metres in the north.
Where are New Zealand’s
alpine zones?
Fellfield
Otago Conservancy
Published by
Department of Conservation
Christchurch
2005
NS0025
The most obvious alpine zone in the country stretches
as a spine down the length of New Zealand’s South
Island. These mountains, the Southern Alps, are
tall but relatively young, and like most New Zealand
mountains, still being actively uplifted. What is
remarkable is the abundance of alpine plants
that have rapidly evolved to adapt to this harsh
environment since the mountains began rising 10–20
million years ago. By comparison, the number of flora
species found in North Island alpine zones is only
about one-third of that found in the Southern Alps. In
the North Island, the best places to experience the
general pattern of northern alpine vegetation is at the
volcano Taranaki/Mt Egmont on the west coast of the
North Island and Ruapehu, Ngauruhoe, and Tongariro
volcanoes in the central part of the island. At these
volcanoes, mixed rain forest gives place to shorter
trees and shrubs, then to the alpine grasslands and
meadows and finally to loose scoria where only the
most tenacious plants maintain a footing.
The sub-zones
Low alpine zone
The low alpine zone begins immediately above the
tree line with a narrow to sometimes wide band
of alpine scrub with a few tall snow tussocks and
herbs. Common species include gaultherias such as
Gaultheria crassa or scarlet snowberry with small, thick
leathery leaves and bell-like flowers from October to
December and Gaultheria depressa, the mountain
snowberry which bears edible white, pink and red
berries. The snow totara (Podocarpus nivalis) grows up
to a metre high compared to the much taller lowland
totara, (Podocarpus totara), while the world’s smallest
pine, the pigmy pine (Lepidothamnus laxifolius)
can be seen trailing over rocks in some alpine areas
growing up to about 5 cm tall, although occasionally
reaching 20 cm. Inaka (Dracophyllum longifolium)
and other related species of turpentine shrub are also
common. A number of resourceful hebes, of which
there are about 90 species in New Zealand, have
radiated in this zone.
Mid alpine zone
Mt Cook lily –
Ranunculus lyalli
Continuing on uphill, the mid alpine zone is dominated
by snow tussocks from the Chionochloa (pronounced
Ki-on-no-clo-ah) family. There are 14 species of
Chionochloa in the high country with C.
crassiuscula a common alpine species
in Southland, Otago and Fiordland, with
leaves that curl spirally when dead and dry.
Tussocks provide shelter for tiny plants and
animals adapted to the alpine temperature
extremes.
The array of summer flowering alpine herbs
can bring even the most uninterested
trampers to their knees for a closer look at
the tiny gentians and orchids. Alpine daisies
(Celmisia) are among the most common
plants in the alpine zone. They flower in
December and January. The great mountain
buttercup (Ranunculus lyallii) – also known
as the Mount Cook lily – is the largest
buttercup in the world, reaching over a
metre in height with large white flowers from
early October to December. Grazing by deer
has much reduced this most famous of the herbs.
While most alpine flowers are seen in summer, the
semiparasitic gentians flower from February to April.
Most New Zealand alpine flowers are white or yellow.
This is believed to be as a result of the preference of
unspecialised flies, beetles, moths and short-tongued
bees that act as pollinators. Other countries feature
more specialised relationships between colourful
alpine flowers and insect pollinators.
High alpine zone
Uppermost is the high alpine zone
which comprises mainly fellfield, ice and
snowfields. Although the fellfield, which are
more or less stable areas of rock debris,
can at first appear barren and lifeless, closer
inspection will reveal small clumps of hardy,
prostrate plants which have adapted to
the harsh environment. The most unusual
of these are the vegetable sheep from the
Haastia and Raoulia groups. These squat
hairy plants which form dense cushions
over the rocks, survive extreme variations
in temperature including months buried
under several feet of snow. During March
and April masses of seeds are ejected and
carried away by the wind. The South Island
edelweiss (Leucogenes grandiceps) flowers from
November to February. Both the leaves and flowers
are densely covered in silvery white wool to prevent
the leaf tissue freezing.
Alpine plants are adapted to their environment through
their stunted size, erratic flowering and elaborate
food storage systems. Clustering close to the ground
and rocks allows the plants to make the most of any
warmth absorbed during the day while the fine layer of
fur on plants, such as edelweiss, helps insulate them.
Threats
•
Grazing of alpine plants by deer and other feral
animals such as thar, chamois, hares, and
possums.
•
Weeds such as wilding pines, which have been
introduced to New Zealand from Europe and
North America, pose a significant threat to the
high country. Already in some places they have
completely changed the landscape.
•
•
Damage by people in vehicles and on trail bikes.
Global warming may allow some alpine species to
out-compete others.
How can you help?
It is important to do your best not to interfere with
the natural environment in the alpine zone, and that
includes not feeding the South Island alpine parrot, the
kea, which is often spotted hanging around carparks
in ski fields. Sometimes the damage you can do is
not obvious, for instance people who stray off formed
roads in their vehicles can do enormous damage to
sensitive environments, so a good rule of thumb is to
always stay on the track.
In the alpine zone it is also important to have good
knowledge of where you are going or to at least be
with someone who has that knowledge. Pay attention
to weather conditions, which change rapidly. Always
take note of Department of Conservation signs or
rules. Dogs are not allowed in national parks and
restrictions may apply elsewhere. Fill in intentions
forms at visitors centres and be sure to remember to
let staff know when you have completed your trip.
For more information
Visit the DOC website at www.doc.govt.nz.
Further reading
Collins Guide to Alpine Plants of New Zealand,
John Salmon
Vegetation of New Zealand, Peter Wardle
The Concise Natural History of New Zealand,
Harriet Fleet
Natural History of New Zealand, Nic Bishop
New Zealand Alpine Plants,
A.F. Mark and Nancy M.Adams