Antarctic Region

one of the zoogeographic and floral regions of the globe. The antarctic region has different boundaries for vegetation and animal life.

Antarctic flora region. This region occupies the southwestern part of America from 40° S latitude, Tierra del Fuego, the Falkland Islands, the antarctic islands, and the oceanic islands of Kerguelen, Auckland, Tristan da Cunha, and others that lie south of 40° S latitude, as well as the entire antarctic continent. The present-day flora of the antarctic region includes 1,600 species of vascular plants, of which 1,200 (that is, 75 percent) are endemic—for example, the Myzodendraceae family, species of southern beech (Nothofagus), Fitzroya, species of treelike ferns (Blechnum), tussock grasses (Poa flabellata), and others. The flora of the antarctic region is distinctive, although it does have some connection with the high-altitude flora of southeastern Australia, Tasmania, New Caledonia, and especially New Zealand. The vegetation of Tierra del Fuego was first described by the Russian scientist N. M. Al’bov in 1899. A characteristic feature of the antarctic regional flora is the presence of several genera and species of plants that grow in the northern subarctic regions and are absent from the temperate and tropical zones of the earth—that is, flora having bipolar distribution. Among these are some species of sphagnum, red crowberry (Empetrum rubrum), as well as wavy Aira (Aira flexuosa), alpine timothy (Phleum al-pinum), primula (Primula farinosa), field chickweed (Cerastium arvense), gentian (Gentiana prostrata), and others.

The antarctic region is divided into three subregions—the subantarctic forest, the antarctic tundra, and the antarctic desert. Evergreens reaching a height of 55 m predominate in the forests between 40° and 48° S latitude. They include antarctic beech (Nothofagus), conifers (Fitzroya), and others. In the second and third tiers are Drimys, protea, bamboos, and treelike ferns; in the east are araucaria and many epiphytes and lianas. Farther south are the so-called Magellanic subantarctic forests of beech, Libocedrus, Podocarpus, and others. The underbrush contains small-leaved barberry, as well as grasses—Chilean gunnera, red crowberry, chickweed, and ferns. On Tierra del Fuego there are many patches of heather. In the east the vegetation resembles that of the steppes, including cushion-like umbellifers (for example, bolax). Tundra formations constitute the only vegetation on the islands of the Antarctic Ocean. There is abundant tussock and giant sedge (Carextrífida) along the coast of the islands, and patches of heather prevail in the inland areas. There are many swamps. The Falkland Islands have 135 species of flowering plants, of which 20 percent are endemic. There are many bipolar species. Rocky terrain almost completely devoid of vegetation prevails on Kerguelen Island. No cereal grains grow on the Falkland Islands, but potatoes, cabbage, carrots, parsley, turnips, lettuce, and other vegetables, as well as black currants, raspberries, and many decorative plants, grow well there. Plantations of southern beech and pine do well in sheltered areas. The flora of Antarctica consists of fungi—moss, lichens, algae, mushrooms, and bacteria. Only on the northwestern coast of the Antarctic Peninsula (Graham Land) does one infrequently encounter up to ten species of short flowering grasses, including species of hair grass. Mosses—approximately 75 species—grow in small beds in coastal oases and on the nunataks, occasionally in the mountains. Most widespread of all are the lichens (approximately 300 species), which are found as close to the south pole as 360 km, at an elevation of 2,000 m above sea level. Blue-green and diatomous algae are found both in the water basins and on the snow.

Antarctic fauna region. This region occupies the whole continent of Antarctica and all the adjoining islands, including the South Shetland Islands and the South Orkney Islands. In addition, this region also includes South Georgia Island, the South Sandwich Islands, the Bouvet Islands, the Prince Edward Islands, the Crozet Islands, Kerguelen Island, Heard Island, Macquarie Island, and the waters of the antarctic seas.

The fauna of the antarctic region is extremely poor and has a unique species composition. There are very few land animals; there are no flying insects, land mammals, or freshwater fish. The small freshwater pools on land are inhabited by rhizopod protozoa, rotifers, free-living nematodes from the roundworm phylum, and several lower crustaceans. Among the lichens and mosses live tardigrades (water bears), mites, and wingless insects such as the springtail and one species of fly with only rudimentary wings. On the subantarctic islands there are several species of beetles, spiders, flies, springtails, and small freshwater mollusks and one species of nonflying butterfly. The absence of flying insects is explained in particular by the almost constant strong winds. There are three endemic species of birds among those few species connected with the land: of the order of sandpipers, the white plover, which eats the eggs of penguins; also the pipit (Anthus ant-arcticus) and the small sea duck (Anas georgica), which lives on South Georgia Island. There are several known cases of intentional or accidental introduction of land mammals and birds to the subantarctic islands, where they later became acclimatized. These include the reindeer and the hooded rat on South Georgia Island, the rabbit on Ker-guelen and Macquarie islands, and the nonflying Maori weka (wood hen), of the family Rallidae, on Macquarie Island.

Living conditions are more advantageous in the antarctic seas than on land; for this reason, the marine fauna of the antarctic region is much richer than the land fauna. The krill is especially characteristic among the marine invertebrates. These are large—up to 6 cm long—plankton crustaceans of the family Euphausiidae, which in the summer form huge accumulations in the upper layers of the water and serve as the main food for a number of species of fish, birds, and mammals. The fauna of the seabed is especially varied. Among the most plentiful animals are the sponges (more than 250 species) and the echinoderms (more than 150 species), and some sea urchins are found at depths of more than 2,300 m. Of the coelenterates, jellyfish weighing up to 156 kg are especially interesting. There are numerous and varied worms, mollusks, and ascidians, especially the colonial ascidian Juliana, more than 40 cm long. The most characteristic family of fish inhabiting the waters of the antarctic seas is Nototheniidae, a perchlike group almost all of whose representatives are endemic. Unique among the fish is the family of white-blooded pike (Chaenichthyidae), whose blood is colorless because of a lack of hemoglobin. In the summer, the bird population includes very numerous tubenoses (order Procellariiformes), among which are the antarctic petrel, Cape pigeon, snow petrel, and silver-grey fulmar; the scavenger of the antarctic—the skua—is also present; albatrosses, petrels, terns, and other birds are not infrequently found. The most typical birds of the antarctic region are the penguins—the large emperor penguin (the most commom), the slightly smaller king penguin, and the small Adélie penguin. Penguins remain in the antarctic region throughout the year, building their nesting colonies on the antarctic coast and the islands. Mammals are represented by pinnipeds and whales. On the shores of Antarctica, near the islands, and in the belt of drift ice are five species of true seals (Phocidae), among which the elephant seal is most closely linked with the land—it is found on the islands and more rarely on the mainland. In the zone of immovable coastal ice are the Weddell seal and the Ross seal; the crabeater seal and the leopard seal are found in the floating ice pack. The eared seals, which are rather numerous in the southern hemisphere, are represented in the antarctic region by the fur seal. Whales are regular summer inhabitants of the antarctic waters, and they are more numerous here than in other regions of the world’s oceans. The presence of massive accumulations of crustaceans creates especially favorable feeding conditions for large herds of whales. Of the baleen whales, the great blue whale, common rorqual, sei whale, humpback whale, lesser rorqual, and occasionally the right whale are encountered here. Of the toothed whales, the antarctic region supports the sperm whale, the bottle-nosed whale, and the killer whale. Most of the abovementioned species are targets of the whaling industry.