Macquarie Island is a sub-antarctic island located approximately halfway between Antarctica and Australia, 1466 km south-east of Tasmania and 1294 km north of the Antarctic continent. The IBA includes the whole island and the nearby Judge and Clerk Islets and Bishop and Clerk Islets. The island lies just to the north of an oceanic boundary, the Antarctic Polar Frontal Zone or Antarctic Convergence, where cold polar waters meet warmer sub-antarctic waters. The island is 34 km long and up to 5 km wide and consists of a long plateau, 200-350 m above sea level, surrounded on all sides by steep slopes or cliffs. Mean temperatures for summer and winter are 7oC and 3oC respectively, and annual mean rainfall is approximately 900mm and falls an average of 310 days each year. Severe earthquakes occur once a decade and landslips are common on steep coastal slopes, the latter due to soil instability caused by overgrazing by rabbits. Management is funded by the Tasmanian State and Commonwealth governments and the Australian Antarctic Division, and up to 50 scientists and support people and a number of tourist vessels visit the island each year. The island has suffered from several introduced species; cats were eradicated in 2000 but this has led to an increase in the numbers of rabbits which are now due to be eradicated. The islands and seas to three nautical miles are a Nature Reserve; the islands and seas to 12 nautical miles are a World Heritage Area; and 162,000 km2 of seas to the east are in the Macquarie Island Marine Park.
Other nesting seabirds include around 660 pairs of the endemic subspecies of Imperial Shag Phalacrocorax albiventer purpurascens, about 49,000 pairs of Antarctic Prion in 1975-1982 (the 1% threshold is 500,000 pairs), small numbers of Fairy Prion and Common Diving-Petrel, unknown numbers of Wilson’s Storm-Petrel (on Bishop and Clerk Islets), Grey Petrel (small numbers re-established after cat eradication in 2000), Blue Petrel (500-600 pairs in 1975-1982), Kelp Gull (low numbers), Sooty Shearwater (1777 burrows counted in 1975-1982 (Brothers 1984) and 50-1000 pairs estimated by Parks and Wildlife Service (2006)) and Antarctic Tern (24 pairs in latest survey); and Soft-plumaged Petrel and Grey-backed Storm-Petrel probably breed. The only other native bird, Pacific Black Duck, is hybridising with introduced Mallards. The Redpoll and Common Starling are considered to be self-introduced aliens (from introduced populations in New Zealand) and are widespread on the island. Wekas were introduced but were eradicated in the 1980s.
Non-bird biodiversity: A breeding ground for approximately 100,000 seals: southern elephant seal, subantarctic fur seal, Antarctic fur seal and New Zealand fur seal; 45 recorded species of vascular plants (but no true woody plants), around 150 bryophytes, over 150 lichens, more than 260 fungi (excluding microfungi), 25 slime molds, at least 120 freshwater algae, and 110 marine and littoral algae.
Pressure/threats to key biodiversity
Ensure that current rabbit and rodent eradication is fully funded and implemented efficiently. Maintain strong quarantine measures.
Conservation responses/actions for key biodiversity
A program to eradicate rabbits and rodents is being implemented from 2008-2015 at a cost of approximately $25 million, funded by the Tasmanian and Australian Governments, with contributions from the World Wildlife Fund and Peregrine Adventures.