New Zealand Subantarctic Islands BioProvince
This BioProvince (as defined by Armen Takhtajan) includes the Auckland Islands, Antipodes Islands, Bounty Islands, Campbell Island, Macquarie Island and the Snares, although the flora of the Bounty Islands appears to have been destroyed by penguins and seals. They lie on a shallow continental shelf in the Southern Ocean east of New Zealand. The Snares and Bounty Island groups are composed of granite and metamorphic rocks, while the others are basic volcanic structures with ages ranging from 25 million to less than 1 million. They experience a cool temperate climate with high rainfall and frequent cloud cover. The flora comprises approximately 250 taxa, 52 of which are endemic. The richest flora of some 233 species occurs on the Auckland Islands while Campbell Island has 115 species, the Antipodes Islands have 60 species, and Macquarie Island has just 35 species. The endemic genera include the monotypic Damnamenia (found on Auckland and Campbell islands) and Pleurophyllum (found on Antipodes, Auckland, Campbell and Macquarie islands). The Auckland Islands also support the southernmost forests in the region and also include tree ferns at their southern limit. A peculiar feature of the islands is the so-called megaherbs, including the endemic Anisotome acutifolia (Ascelpiadaceae), Stilbocarpa polaris (Araliaceae) and three endemic species of Pleurophyllum (Asteraceae). Giant herbs, such as these, are thought to be an evolutionary feature of certain islands, and possibly evolved to more efficiently harvest nutrients from marine aerosols. Their larger size also helps them to retain heat in the cool climate and they also possibly act like solar panels focusing radiant energy towards their growing apex. Recently it has been suggested that some of these giant herbs may represent remnants of the once lush Antarctic vegetation that managed to survive here during the Pleistocene glaciation.
The following accounts for this BioProvince have been written or will be written with particular reference to endemic and locally important species. Accounts available are displayed in green or yellow. Those displayed in red are either in the pipeline or awaiting expert contributions.
|Endemic Vascular Plant Flora|