The History of the Islands
Ovens and middens on Enderby Island suggest Polynesian first discovered the Auckland Islands as early as the 13th century. The islands were rediscovered by a whaling ship called the Ocean in August 1806. At this time fur seals, sea lions and whales were abundant, attracting many sealers and whalers. In 1842, Maori also arrived to establish a settlement bringing dogs and pigs with them. In 1849 the Southern Whale Fishery Company obtained a lease of Auckland Islands and established a settlement. Sealing peaked around 1823, and by 1830 the seals were on the verge of extinction. Whaling was abandoned in 1852. By this time pigs, cats and mice were well established on Auckland Islands.
Two coastwatching stations, at Ranui Cove in Port Ross and Tagua Bay in Carnley Harbour served as outposts during World War II on Auckland Island. The stations were executed by the Public Works Department as part of the Cape Expedition and used for coastwatching and scientific work between 1941 and 1945.
Human Impacts on the Auckland Island Group
Though the Auckland Islands are exceptionally isolated, breathtakingly beautiful and most of all, biologically rich they still remain at risk from both existing and potential invasive species. Their fragile ecosystems have been utterly devastated in a matter of decades by introduced species such as pigs, mice and cats. Particularly vulnerable are the megaherbs as well as nesting seabirds such as Mollymawks. Of the three main islands, only Adams Island remains relatively pristine. Enderby Island has recovered substantially following the removal of introduced mammals including cattle but Auckland Island is still severely impacted by the presence of introduced mammals.
The growth of the shipping trade in the 18th and 19th centuries, led to an explosion in the number of ships travelling from Great Britain to New Zealand via the treacherous Roaring Forties of the Sub-Antarctic. From 1864 to 1907 over 10 ships were wrecked on the islands shores. To provide food for the many shipwrecks and castaways that washed up on the shores of the Auckland Islands, goats, pigs and rabbits were introduced in the mid-1800s. In addition, cats, mice and rats also established, brought on the ships of sealing gangs, whalers and early settlers. In the 1850s, attempts were made to farm the islands but conditions were simply too harsh for sheep and cattle, so settlements were abandoned.
Thanks to painstaking eradication efforts by the Department of Conservation and other partners, many pests have now been removed from the islands. Particular successes include: the removal of goats from Auckland Island in 1991 and the removal of cattle, rabbits and mice from Enderby Island in 1993.
Fortunately, there are many systems in place to prevent pests from reaching the Auckland Islands. The Department of Conservation manages a Quarantine Centre in Invercargill where all equipment, clothing and footwear is checked for seeds, soil and other potential risks. Ships passing through the harbour bound for the Sub-Antarctic also require their hulls and ballast water to be checked for invasive marine species. These measures, as well as a permit system limiting the annual number of visitors to the islands, ensure that the Auckland Islands will remain as pristine as possible.
The impacts of invasive species on the Auckland Islands can be broadly categorised into two areas: consumption and predation, and habitat destruction. Cats hunt the smaller bird species such as White-headed Petrel chicks and even adults. Mice invade nests to eat eggs and researchers have even found disturbing evidence of mice eating Albatross chicks alive.
However, it is the feral pigs on Auckland Island (of which there are an estimated 500-1000) which have the most devastating impact. While the three little pigs in the fairy tale find themselves at risk of losing their homes to the Big Bad Wolf, in the Sub-Antarctic, it is the pigs that are the real threat. Not only do they eat eggs and chicks, but as they are omnivorous, they also devour endemic megaherbs such as the Anisotome latifolia and brightly-coloured Bulbinella rossii. In their search for worms and other grubs, pigs will also root up saplings, destroy nests and penguin and shearwater burrows and rip up tussock. As a direct consequence of pig disturbance, ground nesting birds such as the endemic Auckland Island flightless teal have been eliminated from the main islands. Only small populations remain on remote islands and on cliffs inaccessible to pigs and other predators. Even as recently as the 1970s, the iconic and unique megaherbs of the Sub-Antarctic Islands have been at serious risk of extinction due to the presence of pigs and grazing livestock.
Auckland Island itself has proved to be a more difficult challenge. Its size and rugged terrain mean that any eradication programmes will be expensive, arduous and long.
Research has shown that removal of invasive pests has immediate and powerful effects on biodiversity. On Enderby Island, where megaherbs were at serious risk of extinction during the mid-1900s, there are now abundant populations which have regenerated incredibly successfully following the removal of cattle in 1993. As shown by these success stories, pest removal is extremely effective in maintaining and improving the condition of the islands. Once invasive species have been removed, seabirds can once again thrive without the threat of mammalian predators and hopefully this will help to reverse their current, alarming decline.
The story hasn't yet ended for the invasive species removed from the islands either. Because of their historical isolation and genetic purity, a number of specimens of Enderby Island rabbit, Enderby Island cattle and Auckland Island pig have been removed by the Rare Breeds Conservation Society for preservation and study. Happily, the Auckland Island pigs have even proved to be extremely valuable to science as they have never been exposed to porcine viruses, making them ideal for scientific research into a cure for Type 1 Diabetes.