Introduction and Types
•The word tundra is derived from a Finnish word “tunturi” meaning a tree-less plain. In Russian language tundra means a “marshy treeless landscape”.
•There are two types of tundra’s.
•a. Arctic Tundra: Some five million acres of Arctic tundra stretches across Canada, Northern Europe, Siberia and. Alaska encircling the North Pole.
•b. Alpine Tundra: At lower latitudes a similar pattern of landscape “alpine tundra” occurs in high mountains at altitudes above tree-line (i.e. where trees can grow).
•Both types of tundra’s look similar, featuring low temperature, limited rainfall, very low precipitation rate and poor vegetation.
•The vegetation (often less than 10 cm tall) includes mosses, lichens, sedges and grasses.
•The tundra soils and subsoils are permanently frozen during winter, but in brief summer (which lasts for three months only), the surface layer thaws out.
•The permanently frozen deeper soil (more than 1500 m thick in some region) is called Permafrost.
•Alpine tundras, however, have no permafrost layer below the soil surface.
•The warmest months during summer averages about 10° C. rainfall is scanty, much of the. precipitation falls in the form of snow.
•The total annual rainfall is usually less than 25 cm per year, but the water is often trapped near the surface by the widespread permafrost.
•During winter, thick ice covers the ground and icy winds blow throughout the day.
•The climatic conditions are thus very harsh and not conducive to vegetation growth.
•Trees are not found in tundra because the growing season is very short and moreover, their roots cannot penetrate the permafrost.
•During the short summers, however, when there is nearly constant daylight, plants grow quickly and flower in a rapid burst. Lichens, mosses and grasses form the predominant vegetation.
•The animals that have adapted to survive in such a hostile condition are caribou, reindeer, polar bear, arctic hare, arctic. fox., beavers, lemmings, wolves and others.
•The important arctic birds are snowy owl, ducks, geese, snowy grouse and ptarmigans.
•Vast number of migratory birds throng into tundra’s during summer months.
•Both Arctic birds and mammals frequently become white in color in winter.
•This has been interpreted as protective coloration against predators. In Alpine tundra, mammalian fauns is very poor.
•During summer months, big swarms of insects, such as, black flies, bumble bees, mosquitoes, dragon flies, etc. have been observed in Arctic tundra.
•In Alpine tundra, however flies are scarce, but beetles, grasshoppers and butterflies are common.