Influence of man on vegetation and wildlife of enderby and Rose Islands, Auckland Islands

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Abstract
Two small adjacent sub-antarctic islands having many features in common, but with markedly different modified vegetation, are considered in the light of historical records and field work in 1954 and 1966. When the Auckland Islands were discovered in 1806 Enderby and Rose Islands probably had the same general vegetative pattern with southern rata (Metrosideros umbellata) forest and scrub on south-eastern parts giving way to Poa litorosa tussock on the more exposed north-western parts. Much of the present vegetation on the two Islands has been induced by fire and introduced mammals, the legacy of a period of shipwrecks and attempts at settlement and farming. Large areas of short sward and of dead trees now occur. Tussock grassland has practically disappeared from Enderby, but still covers much of Rose Island. Nowadays, mice (Mus musculus), rabbits (Oryctolagus cuniculus), and feral cattle (Bos taurus) occur in Enderby, and rabbits alone on Rose Island. Their numbers, distribution, and inter-relations with the vegetation are discussed. On Rose Island, where tussock and scrub are increasing, rabbits have markedly declined since 1954, whereas on Enderby an apparent balance has been reached between the introduced mammals and the much modified vegetation. The history and present status of bird and seal populations are described. After early exploitation and virtual extermination, southern royal albatrosses (Diomedea e. epomophora) and seals (Arctocephalus forsteri and Neophoca hookeri) are now increasing. On Enderby there are breeding sea-lions, many native bird species, cattle, and rabbits all in an interacting relationship which is not obviously detrimental to any of them or to the present vegetation. The Auckland Islands have been reserves for the preservation of flora and fauna since 1934 and are potentially valuable fop studying interactions between native and introduced species. Existing environmental trends on Enderby and Rose Islands have positive conservation and scientific values and any manipulation, such as the control of cattle and rabbits, now seems undesirable.