TEXTô Challenging and exotic, Arctic habitats exist around the world at the fringe of the tree line and beyond. At these latitudes, high winds, low temperature and shallow soil conditions limit the ability of woody plants to grow. Along the edges of the tundra is an area of limited tree growth called taiga; this habitat zone is often classified as sub-Arctic.The Arctic is often referred to as "barren ground," which implies a cold, treeless landscape. It is in fact not barren at all, but rather rich in many forms of plant and animal life. Hundreds of species of herbaceous plants, mosses and lichens inhabit Arctic regions. Such plants have developed adaptations to promote photosynthesis at high latitudes, such as retaining leaves for long periods, even over the winter, in order to have mature foliage ready to process sun light as soon as possible in the spring. A number of bird species have adapted to year-round life in the Arctic and sub-Arctic, including Gyrfalcon, Snowy Owl, Common Raven and ptarmigans. In addition, many migratory bird species utilize open Arctic territories as breeding grounds, where they find plentiful food during nesting season plus relative safety from predators. Conspicuous Arctic migrants include waterfowl, shorebirds, skuas and certain finches. Many tundra breeders show a distinct preference for either low, wet tundra or higher-elevation dry tundra.While the Arctic may lack trees, much of the territory (particularly near lakes and rivers) is covered with thick shrub growth, often the low-growing Arctic Willow. These shrub thickets serve as ideal nesting habitat for numerous bird species, such as Northern Shrike, Bluethroat and sparrows.The Aleutian islands represent a specialized Arctic habitat, distinguished by their harsh climate and proximity to Asia. As a result of this location, the Aleutians host many vagrants and migratory species not recorded elsewhere in North America.
