Human interaction
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Protected area[edit]
The Tasmanian Government declared Macquarie Island as a wildlife sanctuary in 1933. The status was changed to a conservation area in 1971, and then in 1972 it was re-designated as a state reserve known as the Macquarie Island Wildlife Reserve. In 1977 the island was declared a Biosphere Reserve under the UNESCO Man and the Biosphere Programme, and it was also listed on the Australia Register of the National Estate. In 1978, the area of the state reserve was extended to the mean low-water mark including the offshore islets, and it was formally named as the Macquarie Island Nature Reserve. Access to the reserve was restricted from 1979 onwards, requiring a permit for all those seeking access to the reserve.
In December 1997, Macquarie Island was listed as UNESCO World Heritage Site, including the reserve and the surrounding waters out to 12 nautical miles. The Macquarie Island Marine Park was established in 1999, and in 2000, the Macquarie Island Nature Reserve was extended in 2000 to include the area out to 3 nautical miles from the island and outlying islets.
Ecotourism cruise vessels visit the island, but the number of visitors has been limited to 2,000 per annum.
Impact of introduced animals[edit]
The island ecology was affected by the onset of European visits in 1810. The island's fur seals, elephant seals and penguins were killed for fur and blubber. Rats and mice that were inadvertently introduced from the ships prospered due to lack of predators. Cats were subsequently introduced deliberately to keep the rats and mice from eating human food stores. In about 1870, rabbits and a species of New Zealand rail (wekas) were left on the island by sealers to breed for food. This caused huge damage to the local wildlife, including the extinction of the Macquarie rail (Gallirallus philippensis macquariensis), the Macquarie parakeet (Cyanoramphus novaezelandiae erythrotis), and an as-yet-undescribed species of teal. By the 1970s, 130,000 rabbits were causing tremendous damage to vegetation.
Feral cats[edit]
The feral cats introduced to the island had a devastating effect on the native seabird population, with an estimated annual loss of 60,000 seabirds. From 1985, efforts were undertaken to remove the cats. In June 2000, the last of the nearly 2,500 cats were culled in an effort to save the seabirds. Seabird populations responded rapidly, but rats and rabbits population increased after the cats were culled, and continued to cause widespread environmental damage.
Rabbits[edit]
The rabbits rapidly multiplied before numbers were reduced to about 10,000 in the early 1980s when myxomatosis was introduced. Rabbit numbers then grew again to over 100,000 by 2006. Rats and mice feeding on young chicks, and rabbits nibbling on the grass layer, has led to soil erosion and cliff collapses, destroying seabird nests. Large portions of the Macquarie Island bluffs are eroding as a result. In September 2006 a large landslip at Lusitania Bay, on the eastern side of the island, partially destroyed an important penguin breeding colony. Tasmania Parks and Wildlife Service attributed the landslip to a combination of heavy spring rains and severe erosion caused by rabbits.
Research by Australian Antarctic Division scientists, published in the 13 January 2009 issue of the British Ecological Society's Journal of Applied Ecology, suggested that the success of the feral cat eradication program has allowed the rabbit population to increase, damaging the Macquarie Island ecosystem by altering significant areas of island vegetation. However, in a comment published in the same journal other scientists argued that a number of factors (primarily a reduction in the use of the Myxoma virus) were almost certainly involved and the absence of cats may have been relatively minor among them. The original authors examined the issue in a later reply and concluded that the effect of the Myxoma virus use was small and reaffirmed their original position. The original authors did not, however, explain how rabbit numbers were greater in previous periods such as the 1970s before the myxoma virus was introduced and when cats were not being controlled, nor how rabbits had built up to such high numbers when cats were present for some 60 years prior to the introduction of rabbits;[citation needed] suggesting that cats were not controlling rabbit populations before the introduction of the myxoma virus.[original research?]
Eradication of rabbits, rats and mice[edit]
On 4 June 2007, a media release by Malcolm Turnbull, Federal Minister for Australia's Environment and Water Resources Board, announced that the Australian and Tasmanian Governments had reached an agreement to jointly fund the eradication of rodent pests, including rabbits, to protect Macquarie Island's World Heritage values. The plan, estimated to cost A$24 million, was based on mass baiting the island similar to an eradication program on Campbell Island, New Zealand, to be followed with teams of dogs trained by Steve Austin over a maximum seven-year period. The baiting was expected to inadvertently affect kelp gulls, but greater-than-expected bird deaths caused the program to be suspended. Other species killed by the baits include giant petrels, black ducks and skuas.
In February 2012, The Australian newspaper reported that rabbits, rats and mice had been nearly eradicated from the island. In April 2012 the hunting teams reported the extermination of 13 rabbits that had survived the 2011 baiting; the last five were found in November 2011, including a lactating doe and four kittens. No fresh rabbit signs were found up to July 2013.
On 8 April 2014, Macquarie Island was officially declared pest-free, after seven years of conservation efforts. This achievement was the largest successful island pest-eradication program attempted to that date. In May 2024, it was reported that the island had remained free of pests for 10 years, with vegetation flourishing.
Populations of multiple bird species have begun to recover. The white-headed petrel (Pterodroma lessonii) that was close to extirpation by 2001 has shown a large increase in breeding success, and the population is now slowly increasing. Two other species of petrel, the grey petrel (Procellaria cinerea) and blue petrel (Halobaena caerulea) that were extinct on the main island from the 1900s, have now returned. Their populations are increasing at around 10% per annum. In 2024, giant petrels and skuas are returning to their numbers of before the baiting. However, ongoing monitoring, along with measures such as the use of biosecurity dogs to check cargo with the island as its destination are necessary, as there are new threats such as climate change and avian influenza. Ongoing monitoring programs are funded by the federal government.
Introduced birds[edit]
Despite being declared pest-free, Macquarie Island is still inhabited by several invasive bird species, such as the domestic mallard and European starling. The self-introduction of domestic mallards from New Zealand has become a threat to the Pacific black duck population on Macquarie Island through introgressive hybridisation.
Introduced invertebrates[edit]
At least 40 species of non-native invertebrates have established themselves on the island, the majority of them small detritivores. In addition, a number of larger‑bodied non‑native species occur, such as the milky slug Deroceras reticulatum, earthworms (Lumbricidae), the terrestrial amphipod Puhuruhuru patersoni and the isopod Styloniscus otakensis, and the predatory flatworms Kontikia andersoni and Arthurdendyus vegrandis.
