IT is not the first time that invasive
species have been the subject of
this column but the recent news
concerning South Georgia means
the subject is worthy of further
mention.
Situated in the South Atlantic to
the east of the Falkland Islands and
north of the Antarctic mainland,
South Georgia is one of
the wildlife gems of the
world.
Home to tens of
thousands of Southern
elephant seals, king
penguins, and countless other sea
birds, it is a must see destination for
any number of cruise ship passengers
who sail the southern oceans during
the Austral summer.
All is not completely rosy though
in what should be this most pristine of
environments. Two invaders from the
northern hemisphere are creating
havoc with the native flora and fauna.
The first is the brown rat which
arrived with whaling and sealing
vessels during the 18th and 19th
centuries. Their numbers are now
estimated in the tens of millions and
they are having a devastating effect on
the island’s birdlife, in particular the
South Georgia pipit and pintail.
A pilot trial in 2011 during which
tons of poisoned bait were laid over
an area exceeding 100 square
kilometres succeeded in removing the
rodents from the location in question.
Now there is a large team of scientists
arriving on the Island with the aim of
extending the trial to a further 500 or
more square kilometres. With three
helicopters and several hundred tons
of poison bait at their disposal, this is
the largest rat eradication programme
ever attempted.
That’s not the only eradication
under way on South Georgia. In 1911,
Norwegian whalers took a small herd
of 10 reindeer to the island to provide
them with fresh meat during their
long periods away from home. They
clearly found the environment to their
liking since, one hundred years later,
that herd has grown to some 3,000
deer.
They are devouring and trampling
the native flora and the nests of
ground-dwelling birds, as well as
causing erosion in numerous areas. It is feared that if left
to their own
devices they will
lead to even further
environmental
degradation.
So, the decision
has been made to
eradicate them and
since it was the
Norwegians who
took them there it
seems only right
that they are now
playing a major role
in the process.
A team of Sami herdsmen has
arrived and using their expertise at
working with reindeer will round up
the deer into corals and slaughter
them with captive bolt pistols. It is
said that some of the meat produced
from the cull will be taken to the
Falkland Islands for sale.
Necessary projects
Clearly the project is a major
undertaking and it is estimated will
take two Austral summers. The
reindeer exist in two main herds
separated by glaciers and there will no
doubt be some “outliers” which will
need to be stalked and shot by rifle.
That both eradication
projects are considered
necessary are clear
indications of the
problems that invasive
species can cause to
environments and the
animals and plants that
live within them, when
such environments have
evolved in isolation over
millions of years.
Removing rats and
reindeer from South
Georgia is expected to have a huge impact on the island’s bird
numbers, enabling it to expand to the
100 million or so pairs estimated to
have previously been present. This is
not just pie in the sky because already
the number of pintail ducklings seen
in the now rat-free area of the island
has exceeded all expectations and
demonstrated the devastating effect
that the rats were having.
The story is also a salutary
reminder, if one were needed, of the
importance of maintaining the
Antarctic mainland completely free of
all invaders and validates the current
policy of leaving nothing behind in
what almost certainly remains the
most unspoilt place on the planet.
