The most striking feature of Macquarie Island is
the abundance of seabirds - Skuas, Shearwaters, Petrels, Prions, Albatross
and of course, penguins - and the mammal fauna, all of which contribute
to the nutrients in the soil. As the island has never been connected
to an adjacent land mass, all flora and fauna has arrived there via long-distance
oceanic dispersal. The flora shows taxonomic linkage to other subantarctic
islands, the continents to the west and the islands to the south of
New Zealand. Those plants which have managed to reach and successfully
colonise the island exhibit a range of strategies for dissemination,
reproduction and colonisation. The flora is rarely over 1 m. tall and
although not particularly diverse has 45 vascular plant species and 91
species of moss as well as a rich population of liverwort and lichen. The
flora is classified as growing in 5 main vegetation formations - grassland,
herbfield, fen, bog and feldmark. Three plants - Azorella macquariensis,
Puccinellia macquariensis and Corybas dienemus
are endemic. Research continues to increase the number of species discovered
and reclassified. In 1981 Macquarie Island became a restricted area and
collection of scientific specimens requires a permit.
UPDATE 15 July, 2006
Since this item was first presented in 1999/2000 major changes have
occurred to the island vegetation. Tasmanian University scientists, Justin
Shaw and Jenny Scott, have written a paper showing the devastation by rabbits
during the past six years when the last of the feral cats was eradicated.
This element, plus the fact that rabbits have developed a natural resistance
to myxomatosis, together with a climate change bringing warmer and drier
winters, has enabled rabbits to breed successsfully all year round. Until
recently, winter breeding was unsuccessful because the kittens would drown
or females were too thin to breed.
Pest Eradication Update December 2007
Following the announcement that the Tasmanian and Australian Government
would jointly fund the $24.6 million project, Tasmanian Parks & Wildlife
Service have announced details of a seven-year project to rid the island
of rabbits and rodents. The plan will involve helicopters dropping pellet
baits targeting rabbits, rats and mice.
Work now under way includes construction of sixteen 5x5 metre plots
protected by rabbit-proof fencing in a bid to protect specific locations
of plant species that are under severe pressure. These will complement
other existing scientific exclosure plots and prevent reintroduction as
rabbits are removed.
Other actions include over-flight trials of helicopters and test baiting
around penguin colonies to determine the response of the penguins to these
activities. Discussions have also been held with skilled dog trainers.
Dogs will have a crucial role in the success of the project, following
up the major baiting phase with on-ground hunting of surviving rabbits.
The dogs will assist hunters and must be trained to focus on rabbits while
avoiding non-target species, in particular native animals More information
about the eradication program can be found on Parks and Wildlife Service
Update November, 2009
In December 2008, a botanist from the Australian Antarctic Division
first noticed that more than 90 per cent of this endemic cushion plant
had died or is dying. There are a number of possible reasons for this die-back,
the first being that the mean temperature has increased by more than half
a degree over the past 50 years and the island is drying out and warming
up. It is not so much a case of less rain than a change in rain and wind
patterns. This situation is affecting other sub-polar islands around
Secondly there is the over-population of rabbits (since the eradication
of feral cats - see above), which are causing a lot of physical damage.
Warmer temperatures has enabled the rabbit kittens to survive. This
problem should be ameliorated when the hunters and their specially trained
dogs set their sights on the island in May 2010.
Thirdly a pathogen may be responsible for the plant's plight.
It is now considered to be critically endangered and the Antarctic Division
has joined forces with the Royal Tasmanian Botanical Gardens in Hobart,
the DPIPWE (Dept of Primary Industries, Parks, Water and Environment),
Parks and Wildlife, UTAS (University of Tasmania) and New Town Laboratory
to try to save this cushion plant population. Dr Jenni Whinan, senior
ecologist of DPIPWE fears any increase in the die-back will
bring a new set of environmental concerns including soil erosion, to the
Seeds of Azorella macquariensis have been collected for
the Millenium Seed Bank and plant material has been set aside for tissue
culture testing. Twenty healthy plants, currently in quarantine,
are also to be located at the botanical gardens in Hobart. Work is under
way to try and mimic the sub-polar conditions the species needs to survive
while in captivity."It is proving very difficult to give the plant the
same conditions here", Dr Whinan said. "The lights have been changed in
the quarantine area where the plants are housed, along with temperature,
and fans are used to try and keep the plants, which normally grow in very
exposed conditions, as healthy as we can."
Tight biosecurity measures are in place to ensure any pathogen does
not leave the island and cause environmental problems in mainland Tasmania.
Pest Eradication Update 18 April 2010
In an effort to restore environmental damage caused by the excessive
rabbit population, special baiting is about to commence. This will be followed
in August by the use of hunting dogs which have been especially trained
to be “prey specific”, to protect the general wildlife.
Seed from some of the heavily damaged plant species have been collected
and brought back to the Royal Hobart Botanical Gardens, for germination and
ultimately used to repair the depleted areas.
Pest Eradication Update #2 27 August 2010
The pest eradication programme, planned for August, when
highland areas were to be baited, with follow-up hunting, had to be abandoned
due to extremely bad weather. Some baits, already laid, had the unfortunate
effect of poisoning some seabirds. The programme will be resumed in
Pest Eradication Update #3 20 April 2011 (Adapted
from a report by Felicity Ogilvie)
Another attempt is underway to try to kill every rabbit, rat and mouse
on the island. In 2010 the program had to be stopped because of bad weather,
but the staff are heading to the island a lot earlier this year. There
was also some collateral damage last year when native sea birds were killed
by the bait. Steps have been taken to prevent that from happening again.
After an extensive review process extra staff are being taken on site to
collect the carcasses. There is one big difference this year
- calicivirus has been released this summer which has been enormously successful
and has taken out at least 50% of the rabbit population already. It’s
too early to know if the baiting has made any difference to the destruction
of the vegetation and the land slips, but early
signs suggest that vegetation could recover extemely quickly once continued
by animals ceases.
Pest Eradication Update #4 26 April 2012. (Adapted
from a report by Fiona Breen)
Greenery returns to rabbit-ravaged hills
The arrival of hunting dogs and their handlers, added to the
affects of the calicivirus was almost the final straw in the decimation of
the rabbits. The island is already showing a rapid regrowth of plants,
especially the endemic cabbage and the tall tussock grass and there is a
return of seabirds which are breeding more successfully since the predatory
rats have gone. Now that poisons are not used to kill the rabbits,
the sad loss of seabirds (who died after eating the carcasses) has not recurred.
A new team of six dog handlers, 10 dogs and another group of hunters will
keep up the search. Another group of hunters will follow this one in 2014
until every rabbit is caught.
For the many who work and visit this magnificent island there's a real hope
that the eradication team will succceed and the island will return to the
flora and fauna sanctuary of the past.
References and acknowledgements
1. Flora of Australia Volume 50, Oceanic
Islands 2 . Australian Government
Publishing Service, Canberra
2. Subantarctic Macquarie Island.
P M Selkirk, R D Seppelt and D R Selkirk,
Cambridge University Press
3. J. R. Croft and M. M. Richardson - Australian
National Botanic Gardens, Canberra
The Australian Plants Society would like to thank
the Royal Tasmanian Botanical Gardens for their kind co-operation in
the preparation of this item.
Special thanks to M. Fountain and M. Brown of
the Royal Tasmanian Botanical Gardens, Hobart