There is little land in the Southern Hemisphere at the latitudes where tundra might be expected. In the Northern Hemisphere the biome occurs primarily poleward of 60° N on the continental masses of North America and Eurasia and on Arctic islands. South America only extends poleward to about 55° S. However, several island groups in the South Atlantic Ocean at latitudes as far north as 50° S host a treeless vegetation similar to Arctic tundra: dwarf shrubs, perennial forbs, mosses, and lichens; as well as in some instances tussock grasses, cushion plants and megaherbs resembling tropical alpine tundra in the Andes Mountains and on some African peaks (See Altitudinal Zonation in the Tropics). Subantarctic Kerguelen Island in the South Indian Ocean and New Zealand’s subantarctic Auckland and Campbell Islands in the South Pacific are other places with such vegetation. Marine birds and mammals comprise the dominant animal life on all these islands.
The Antarctic tundra climate is under the influence of the Southern Polar Front, and the most equatorward islands serve as a transition zone from cool temperate climates to true Antarctic conditions. Mean annual temperature is less than 32° F (0° C), but summer (February) mean monthly temperatures may be as high as 50° F (10° C).
Ice-shrouded Antarctica offers little opportunity for the establishment of a tundra-like vegetation. The true Antarctic begins south of 60° S, the internationally agreed northern boundary of the Southern Ocean. On sunny, north-facing slopes of the Antarctic Peninsula, South Orkneys, and South Shetland Islands, as far south as 68° 12’S, there are but two species of flowering plant, the Antarctic pearlwort (Colobanthus quitensis) and Antarctic hairgrass (Deschampsia antarctica). Southward there are none, but 30 kinds of moss, 1 liverwort species, and 125 lichens have been reported. Precipitous ice-free rock faces may host bright orange and yellow lichens as well as less visible green and gray crustose lichens. Avian and mammalian life depends upon the bounty of the sea. Marine birds such as Gentoo, Adelie and Chinstrap penguins and Imperial Cormorants nest in large colonies on ice-free surfaces in the austral spring and summer. The only terrestrial bird is the Snowy Sheathbill (Chionis albus), an omnivorous opportunist that feeds on carrion, eggs, and fecal matter—a resource quite plentiful at penguin breeding sites.
Antarctic hairgrass and Antarctic pearlwort, the only two vascular plants growing in the Antarctic.
(Sharon Chester, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons)
Brightly colored lichens may adorn ice-free rock faces.
Gentoo Penguins. Snow is discolored from their droppings, red as a result of their largely krill diet.
Snowy sheathbill is the only non-marine bird breeding in the Antarctic and the only bird there without webbed feet.
Subantarctic islands host a much richer species composition than the Antarctic, although they are often quite dependent on nutrients carried from the sea by marine birds and mammals. See Falkland Islands, South Georgia.
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Sources: Burton, Robert and John Croxall. 2012. A Field Guide to the Wildlife of South Georgia. South Georgia Heritage Press.Princeton, NJ, Princeton University Press. Quinn, Joyce A. 2008. Arctic and Alpine Biomes. Greenwood Guides to the Biomes of the World. Westport, MA,
Greenwood Press. Strange, Ian. 1992. A Field Guide to the Wildlife of the Falkland Islands and South Georgia. London, HarperCollins.
