As winter grips the continent’s south and Australia’s upland regions become blanketed by snow,
our alpine plants and animals rely on clever strategies to survive.Cold comforts
NATURE
Wild Australia
with John PickrellPHOTO CREDIT: ROSS DUNSTAN / AUSTRALIAN GEOGRAPHIC. SCIENTIFIC NAME:
Vombatus ursinus
JOHN PICKRELL
is a former AUSTRALIAN
GEOGRAPHIC editor.
Follow him on
Twitter: @john_pickrell.W
HEN YOU
think of
Australia,
you don’t typically
picture wintry white
scenes. And yet parts
of the south-east, and
to a lesser extent
Tasmania’s mountainous regions, receive
significant snow during colder months.
The Australian Alps – the Great
Dividing Range part that stretches from
NSW into Victoria – usually begin
receiving heavy snowfalls in June.
Temperatures here from June to August
regularly fall below 0oC. (Bureau of
Meteorology data show Australia’s
coldest ever recorded temperature was
–23oC, at Charlotte Pass in Kosciuszko
National Park on 29 June 1994.)
It is in June when the many plants
and animals that live here start to adopt
key strategies to cope with scarce food,
cold temperatures and long nights.
Wombats are among the few larger
marsupials that remain active above the
snowline in winter. Echidnas are also
present in the alpine zone, but hiber-
nate during the coldest months.
Many smaller mammals have learnt
to live beneath the snow. There’s a gap
known as the subnivean space between
the underside of the snow and the
ground, where native creatures such
as the bush rat, broad-toothed rat,
mountain pygmy possum and Swain-
son’s antechinus move and forage in
relatively constant temperatures.
Some species share body warmth
at night by nesting together and feast
on seeds, grasses and insects, which
are easier to catch in cold conditions
because they move more slowly. In
winter these tiny mammals are also
more free to move around than in
summer, when they are vulnerableout in the open to cats and foxes.
Other small animals, such as reptiles
like the alpine water skink and frogs,
hibernate during winter and some
lizard species have been found nestled
together in groups of 100 or more in
spaces in snow-gum logs. Corroboree
and Baw Baw frogs are cold-tolerant
and inactive in winter; at summer’s
end they lay eggs that enter a state of
paused development until the snow
starts to melt again and floods bogs and
streams with fresh water. Fish such as
mountain galaxias hibernate in the
mud of frozen alpine creeks.
More than half the bird species of
the Alps avoid the winter completely
by migrating away when it’s coldest.
For example, olive-backed orioles and
satin flycatchers head north to warmer
climes, while flame robins, nankeen
kestrels and pied currawongs move
down to lower altitudes where food
is more plentiful.
Plants also have strategies for coping
with wintry conditions. In Tasmania’s
mountains, Australia’s only cold-climate
deciduous tree, the fagus – or the
deciduous beech – flushes with reds
and golds in autumn, withdrawing
nutrients from its leaves as it drops
them completely ahead of winter(see AG 131). Tasmania’s alpine
herb fields also have pillow-shaped,
low-growing cushion plants that
mature very slowly and are particularly
adapted to cold and windy conditions.
Other alpine species, such as snow
gums, have evolved small waxy leaves
as a defence against the cold. These
pretty eucalypts are sculpted by
highland winds, and, with boughs
heavily laden with snow, are the
archetypal image of winter in Austral-
ia’s Snowy Mountains. Australian alpine
regions are unique in the world for not
having a distinct tree line (the point
above which no trees grow) and snow
gums can even occasionally be found
in protected spots near the summits
of peaks in Kosciuszko NP.
So, if you’re lucky enough to visit
Australia’s snowfields this year, don’t
make the mistake of thinking there
isn’t much life about: the coldest parts
of our continent teem with life
specially adapted over millions of years
to cope with the harsh conditions.
Sadly, this means they are also some of
our species most vulnerable to climate
change, because they have nowhere to
retreat to as their habitats dwindle.May. June 37A common wombat
trundles through the snow
in a NSW ski field.