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Australasian Plant Conservation

Originally published in Australasian Plant Conservation 21(2) September - November 2012, p 25-26

Azorella macquariensis – Battling for survival in the furious fifties

Lorraine Perrins

Royal Tasmanian Botanical Gardens, Hobart, Tas. Email: L.perrins@rtbg.tas.gov.au

Royal Tasmanian Botanical Gardens staff member Michelle Lang on Macquarie Island in 2010

Royal Tasmanian Botanical Gardens staff member Michelle Lang on Macquarie Island in 2010. Photo: Michelle Lang

Azorella macquariensistrial potted collection on Macquarie Island

Azorella macquariensistrial potted collection on Macquarie Island, December 2011. Photo: A.Pyrke

Macquarie Island

Lying in the ‘Furious Fifties’ approximately 1545km Southeast of Tasmania, Macquarie Island is an Australian Subantarctic Territory managed by the Tasmanian Government Parks and Wildlife Service. The origin of the island is unique; being a very rare example of recently uplifted oceanic crust formed around 11 million years ago, and is the only place where the earth’s mantle is being exposed above sea level. Each year thousands of oceanic birds and mammals congregate on Macquarie Island to breed in phenomenal numbers.

Sir Douglas Mawson, the Australian polar explorer, being well aware of the importance of Macquarie Island, championed a large public movement successfully petitioning the Tasmanian government to close a penguin oil processing facility on the island in 1920. This action is widely considered to have been the world’s first wildlife conservation movement. The entire Island has been managed as a nature reserve since 1970 and was inscribed on the World Heritage List in 1997 on the basis of its “outstanding natural universal values”.

Cushion dieback

Protecting an area does not guarantee the safety of all its inhabitants, and in December 2008 dying back of the Macquarie Island Cushion plant, Azorella macquariensis, was noticed by Australian Antarctic Division (AAD) staff. Azorella macquariensis is one of only four plants endemic to Macquarie Island and is considered the keystone species of the feldmark, a plant community on the sparse plateau uplands, covering 45% of the Island.

Since the dieback was first noted A. macquariensis has undergone a catastrophic decline. It is now evident across the plant’s entire range and it is anticipated that it could become extinct in the wild within a few years. Unfortunately the demise of the Azorella may mean that the entire feldmark community is at risk of collapse.

The Macquarie Island Pest Eradication Program has made good progress towards the elimination of rabbits on the island and there are initial signs of the flora recovering. Rabbits, however, have not been the cause of the A. macquariensis dieback. The harsh plateau uplands have too hostile a climate and provide minimal browsing opportunities for rabbits. Although there is still much research to be done it appears that the cause may be multifactoral and will not be resolved in the short term. Research to date has involved scientists from Universities in South Africa and Canberra, as well as the Australian Antarctic Division, the Biodiversity Conservation Branch of the Tasmanian Government, and staff from the Tasmanian Parks and Wildlife Service (PWS) and the Royal Tasmanian Botanical Gardens (RTBG).

Ex-situ collections

To prevent the total extinction of this plant it is vital that an ex-situ collection is maintained. This can be done by collecting and storing seed, however there has been limited success in obtaining adequate quantity of seed because of the difficulties of collecting in Macquarie Island’s climate. Some germination studies are being currently performed at the RTBG with a small amount of material from a 2010 seed collection and initial results suggest that this species exhibits physiological dormancy.

Maintaining individual plants as an ex-situ collection at the RTBG has not been possible due to difficulties with the strict quarantine and the harsh environmental conditions required to grow this species. In March 2010 a RTBG staff member travelled down to Macquarie Island to set up a trial, potted conservation collection situated away from infected areas and artificially irrigated.

The plants are monitored via monthly photographs sent from rangers on the Island. They are still growing well making this a successful way of maintaining a protected collection of this species.

Long-term challenges

Although all the environmental conditions can be met with an on-island, living collection, it still remains a costly exercise. The logistics of transporting equipment and resources down to Macquarie Island are extremely expensive. However it appears to be our best option in buying time to understand fully the factors causing the Azorella dieback and insuring that this species is conserved for the future.

Plans are now in place to expand the ex-situ collection to 54 individual plants collected from across the Island. This collection will also serve as a seed orchard, where individual plants may be cross-pollinated to hopefully enhance seed-set and broaden the genetic make-up of the seed collected.

The RTBG has been awarded a partial grant from the prestigious Mohamed bin Zayed Species Conservation Fund to assist with the development of the ex-situ collection. The Mohamed bin Zayed Species Conservation Fund is a significant philanthropic endowment established to provide grants to individual species conservation initiatives, recognise leaders in the field of species conservation, and elevate the importance of species in the broader conservation debate. It is funded entirely by His Highness General Sheikh Mohamed bin Zayed Al Nahyan, Crown Prince of Abu Dhabi, and is one of the few international conservation grants available to single species conservation. The RTBG would like to acknowledge the Fund for their generous support. More information about the Mohamed bin Zayed Species Conservation Fund can be found at - http://www.mbzspeciesconservation.org/

Can you help?

The RTBG still requires $10,000 for this program and is currently running an appeal to raise the remaining funds. Brochures can be accessed electronically via the RTBG website – www.rtbg.tas.gov.au/conservation, (follow the link to the Azorella macquariensis page). Any donations would be gratefully received and are tax deductible.

If you would like to find out more about this program please contact Lorraine Perrins, Curator Subantarctic Island Flora and Conservation Collections on (03) 6236 3082, or Natalie Tapson, RTBG Horticultural Botanist (03) 62363052.