In physical geography, tundra (/ˈtʌndrə, ˈtʊn-/) is a type of biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра (tûndra) from the Kildin Sami word тӯндар (tūndâr) meaning "uplands", "treeless mountain tract". Tundra vegetation is composed of dwarf shrubs, sedges and grasses, mosses, and lichens. Scattered trees grow in some tundra regions. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or timberline.
Tundra in Greenland
Map showing Arctic tundra
|Area||11,563,300 km2 (4,464,600 sq mi)|
Arctic tundra occurs in the far Northern Hemisphere, north of the taiga belt. The word "tundra" usually refers only to the areas where the subsoil is permafrost, or permanently frozen soil. (It may also refer to the treeless plain in general, so that northern Sápmi would be included.) Permafrost tundra includes vast areas of northern Russia and Canada. The polar tundra is home to several peoples who are mostly nomadic reindeer herders, such as the Nganasan and Nenets in the permafrost area (and the Sami in Sápmi).
Arctic tundra contains areas of stark landscape and is frozen for much of the year. The soil there is frozen from 25 to 90 cm (10 to 35 in) down, making it impossible for trees to grow. Instead, bare and sometimes rocky land can only support certain kinds of Arctic vegetation, low growing plants such as moss, heath (Ericaceae varieties such as crowberry and black bearberry), and lichen.
There are two main seasons, winter and summer, in the polar tundra areas. During the winter it is very cold and dark, with the average temperature around −28 °C (−18 °F), sometimes dipping as low as −50 °C (−58 °F). However, extreme cold temperatures on the tundra do not drop as low as those experienced in taiga areas further south (for example, Russia's and Canada's lowest temperatures were recorded in locations south of the tree line). During the summer, temperatures rise somewhat, and the top layer of seasonally-frozen soil melts, leaving the ground very soggy. The tundra is covered in marshes, lakes, bogs and streams during the warm months. Generally daytime temperatures during the summer rise to about 12 °C (54 °F) but can often drop to 3 °C (37 °F) or even below freezing. Arctic tundras are sometimes the subject of habitat conservation programs. In Canada and Russia, many of these areas are protected through a national Biodiversity Action Plan.
Tundra tends to be windy, with winds often blowing upwards of 50–100 km/h (30–60 mph). However, in terms of precipitation, it is desert-like, with only about 15–25 cm (6–10 in) falling per year (the summer is typically the season of maximum precipitation). Although precipitation is light, evaporation is also relatively minimal. During the summer, the permafrost thaws just enough to let plants grow and reproduce, but because the ground below this is frozen, the water cannot sink any lower, and so the water forms the lakes and marshes found during the summer months. There is a natural pattern of accumulation of fuel and wildfire which varies depending on the nature of vegetation and terrain. Research in Alaska has shown fire-event return intervals (FRIs) that typically vary from 150 to 200 years, with dryer lowland areas burning more frequently than wetter highland areas.
The biodiversity of tundra is low: 1,700 species of vascular plants and only 48 species of land mammals can be found, although millions of birds migrate there each year for the marshes. There are also a few fish species. There are few species with large populations. Notable animals in the Arctic tundra include reindeer (caribou), musk ox, Arctic hare, Arctic fox, snowy owl, lemmings, and even polar bears near the ocean. Tundra is largely devoid of poikilotherms such as frogs or lizards.
Due to the harsh climate of Arctic tundra, regions of this kind have seen little human activity, even though they are sometimes rich in natural resources such as petroleum, natural gas and uranium. In recent times this has begun to change in Alaska, Russia, and some other parts of the world: for example, the Yamalo-Nenets Autonomous Okrug produces 90% of Russia's natural gas.
A severe threat to tundra is global warming, which causes permafrost to melt. The melting of the permafrost in a given area on human time scales (decades or centuries) could radically change which species can survive there.
Another concern is that about one third of the world's soil-bound carbon is in taiga and tundra areas. When the permafrost melts, it releases carbon in the form of carbon dioxide and methane, both of which are greenhouse gases. The effect has been observed in Alaska. In the 1970s the tundra was a carbon sink, but today, it is a carbon source. Methane is produced when vegetation decays in lakes and wetlands.
The amount of greenhouse gases which will be released under projected scenarios for global warming have not been reliably quantified by scientific studies, although a few studies were reported to be underway in 2011. It is uncertain whether the impact of increased greenhouse gases from this source will be minimal or massive.
In locations where dead vegetation and peat has accumulated there is a risk of wildfire such as the 1,039 km2 (401 sq mi) of tundra which burned in 2007 on the north slope of the Brooks Range in Alaska. Such events may both result from and contribute to global warming.
Antarctic tundra occurs on Antarctica and on several Antarctic and subantarctic islands, including South Georgia and the South Sandwich Islands and the Kerguelen Islands. Most of Antarctica is too cold and dry to support vegetation, and most of the continent is covered by ice fields. However, some portions of the continent, particularly the Antarctic Peninsula, have areas of rocky soil that support plant life. The flora presently consists of around 300–400 lichens, 100 mosses, 25 liverworts, and around 700 terrestrial and aquatic algae species, which live on the areas of exposed rock and soil around the shore of the continent. Antarctica's two flowering plant species, the Antarctic hair grass (Deschampsia antarctica) and Antarctic pearlwort (Colobanthus quitensis), are found on the northern and western parts of the Antarctic Peninsula. In contrast with the Arctic tundra, the Antarctic tundra lacks a large mammal fauna, mostly due to its physical isolation from the other continents. Sea mammals and sea birds, including seals and penguins, inhabit areas near the shore, and some small mammals, like rabbits and cats, have been introduced by humans to some of the subantarctic islands. The Antipodes Subantarctic Islands tundra ecoregion includes the Bounty Islands, Auckland Islands, Antipodes Islands, the Campbell Island group, and Macquarie Island. Species endemic to this ecoregion include Nematoceras dienemum and Nematoceras sulcatum, the only subantarctic orchids; the royal penguin; and the Antipodean albatross.
There is some ambiguity on whether Magellanic moorland, on the west coast of Patagonia, should be considered tundra or not. Phytogeographer Edmundo Pisano called it tundra (Spanish: tundra Magallánica) since he considered the low temperatures key to restrict plant growth.
Alpine tundra does not contain trees because the climate and soils at high altitude block tree growth. The cold climate of the alpine tundra is caused by the low air temperatures, and is similar to polar climate. Alpine tundra is distinguished from arctic tundra in that alpine tundra typically does not have permafrost, and alpine soils are generally better drained than arctic soils. Alpine tundra transitions to subalpine forests below the tree line; stunted forests occurring at the forest-tundra ecotone (the treeline) are known as Krummholz.
Alpine tundra occurs in mountains worldwide. The flora of the alpine tundra is characterized by plants that grow close to the ground, including perennial grasses, sedges, forbs, cushion plants, mosses, and lichens. The flora is adapted to the harsh conditions of the alpine environment, which include low temperatures, dryness, ultraviolet radiation, and a short growing season.
Tundra climates ordinarily fit the Köppen climate classification ET, signifying a local climate in which at least one month has an average temperature high enough to melt snow (0 °C (32 °F)), but no month with an average temperature in excess of 10 °C (50 °F). The cold limit generally meets the EF climates of permanent ice and snows; the warm-summer limit generally corresponds with the poleward or altitudinal limit of trees, where they grade into the subarctic climates designated Dfd, Dwd and Dsd (extreme winters as in parts of Siberia), Dfc typical in Alaska, Canada, parts of Scandinavia, European Russia, and Western Siberia (cold winters with months of freezing), or even Cfc (no month colder than −3 °C (27 °F) as in parts of Iceland and southernmost South America). Tundra climates as a rule are hostile to woody vegetation even where the winters are comparatively mild by polar standards, as in Iceland.
Despite the potential diversity of climates in the ET category involving precipitation, extreme temperatures, and relative wet and dry seasons, this category is rarely subdivided. Rainfall and snowfall are generally slight due to the low vapor pressure of water in the chilly atmosphere, but as a rule potential evapotranspiration is extremely low, allowing soggy terrain of swamps and bogs even in places that get precipitation typical of deserts of lower and middle latitudes. The amount of native tundra biomass depends more on the local temperature than the amount of precipitation.
The Aleutian Islands (; Russian: Алеутские острова; Aleut: Tanam Unangaa, literally "Land of the Aleuts", possibly from Chukchi aliat, "island"; also called the Aleut Islands or Aleutic Islands) are a chain of 14 large volcanic islands and 55 smaller ones belonging to both the U.S. state of Alaska and the Russian federal subject of Kamchatka Krai. They form part of the Aleutian Arc in the Northern Pacific Ocean, occupying an area of 6,821 sq mi (17,666 km2) and extending about 1,200 mi (1,900 km) westward from the Alaska Peninsula toward the Kamchatka Peninsula in Russia, and mark a dividing line between the Bering Sea to the north and the Pacific Ocean to the south. Crossing longitude 180°, at which point east and west longitude end, the archipelago contains both the westernmost part of the United States by longitude (Amatignak Island) and the easternmost by longitude (Semisopochnoi Island). The westernmost U.S. island in real terms, however, is Attu Island, west of which runs the International Date Line. While nearly all the archipelago is part of Alaska and is usually considered as being in the "Alaskan Bush", at the extreme western end, the small, geologically related Commander Islands belong to Russia.
The islands, with their 57 volcanoes, form the northernmost part of the Pacific Ring of Fire. Physiographically, they are a distinct section of the larger Pacific Border province, which in turn is part of the larger Pacific Mountain System physiographic division.
These Islands are most known for the battles and skirmishes that occurred there during the Aleutian Islands Campaign of World War II. It was one of only two attacks on the United States during that war.Alpine tundra
Alpine tundra is a type of natural region or biome that does not contain trees because it is at high elevation. As the latitude of a location approaches the poles, the threshold elevation for alpine tundra gets lower until it reaches sea level, and alpine tundra merges with polar tundra.
The high elevation causes an adverse climate, which is too cold and windy to support tree growth. Alpine tundra transitions to sub-alpine forests below the tree line; stunted forests occurring at the forest-tundra ecotone are known as Krummholz. With increasing elevation it ends at the snow line where snow and ice persist through summer.
Alpine tundra occurs in mountains worldwide. The flora of the alpine tundra is characterized by dwarf shrubs close to the ground. The cold climate of the alpine tundra is caused by adiabatic cooling of air, and is similar to polar climate.Antarctic Peninsula
The Antarctic Peninsula is the northernmost part of the mainland of Antarctica, located at the base of the Southern Hemisphere.
At the surface, it is the biggest, most prominent peninsula in Antarctica as it extends 1,300 km (810 miles) from a line between Cape Adams (Weddell Sea) and a point on the mainland south of Eklund Islands. Beneath the ice sheet which covers it, the Antarctic Peninsula consists of a string of bedrock islands; these are separated by deep channels whose bottoms lie at depths considerably below current sea level. They are joined together by a grounded ice sheet. Tierra del Fuego, the southernmost tip of South America, lies only about 1,000 km (620 miles) away across the Drake Passage.The Antarctic Peninsula is currently dotted with numerous research stations and nations have made multiple claims of sovereignty. The peninsula is part of disputed and overlapping claims by Argentina, Chile and the United Kingdom. None of these claims have international recognition and, under the Antarctic Treaty System, the respective countries do not attempt to enforce their claims. The British claim is recognised though by Australia, France, New Zealand and Norway. Argentina has the most bases and personnel stationed on the peninsula.Copart 200
The Copart 200 was a race in the NASCAR Camping World Truck Series which took place at the Milwaukee Mile.East Antarctica
East Antarctica, also called Greater Antarctica, constitutes the majority (two-thirds) of the Antarctic continent, lying on the Indian Ocean side of the continent, separated from West Antarctica by the Transantarctic Mountains. It lies almost entirely within the Eastern Hemisphere and its name has been accepted for more than a century. It is generally higher than West Antarctica and includes the Gamburtsev Mountain Range in the centre.
Apart from small areas of the coast, East Antarctica is permanently covered by ice. The only terrestrial plant life is lichens, mosses and algae clinging to rocks, and there are a limited range of invertebrates including nematodes, springtails, mites and midges. The coasts are the breeding ground for various seabirds and penguins, and the leopard seal, Weddell seal, elephant seal, crabeater seal and Ross seal breed on the surrounding pack ice in summer.Lambeau Field
Lambeau Field is an outdoor athletic stadium in the north central United States, located in Green Bay, Wisconsin. The home field of the Green Bay Packers of the National Football League (NFL), it opened in 1957 as City Stadium, replacing the original City Stadium at East High School as the Packers' home field. Informally known as New City Stadium for its first eight seasons, it was renamed in August 1965 in memory of Packers founder, player, and long-time head coach, Curly Lambeau, who had died two months earlier.The stadium's street address has been 1265 Lombardi Avenue since August 1968, when Highland Avenue was renamed in honor of former head coach Vince Lombardi. It sits on a block bounded by Lombardi Avenue (north); Oneida Street (east); Stadium Drive and Valley View Road (south); and Ridge Road (west). The playing field at the stadium has a conventional north-south alignment, at an elevation of 640 feet (195 m) above sea level.The stadium completed its latest renovation in the summer of 2013 with the addition of 7,000 seats high in the south end zone. About 5,400 of the new seating is general, while the remaining 1,600 seats are club or terrace suite seating. With a capacity of 81,441, Lambeau Field is the fifth-largest stadium in the NFL with standing room, but is fourth in normal capacity. It is now the largest venue in the state, edging out Camp Randall Stadium (80,321) at the University of Wisconsin in Madison.
Lambeau Field is the oldest continually operating NFL stadium. In 2007, the Packers completed their 51st season at Lambeau, breaking the all-time NFL record set by the Chicago Bears at Wrigley Field (1921–70). (While Soldier Field in Chicago is older, it was not the home of the Bears until 1971.) Only the Boston Red Sox at Fenway Park and the Chicago Cubs at Wrigley have longer active home-field tenures in American professional sports.Lucas Deep Clean 200
The Lucas Deep Clean 200 was a NASCAR Camping World Truck Series race held at Nashville Superspeedway in Gladeville, Tennessee. The race, originally held in August, moved to July for the 2011 season. The event replaces a race that was held on the same date at nearby Nashville Speedway USA from 1996 to 2000. The race was removed from the schedule after 2011 along with the spring race due to the track shutting down in 2012.Montane ecosystems
Montane ecosystems refers to any ecosystem found in mountains. These ecosystems are strongly affected by climate, which gets colder as elevation increases. They are stratified according to elevation. Dense forests are common at moderate elevations. However, as the elevation increases, the climate becomes harsher, and the plant community transitions to grasslands or tundra.Nearctic realm
The Nearctic is one of the eight biogeographic realms constituting the Earth's land surface.
The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America that are not in the Nearctic realm are Eastern Mexico, Southern Florida, coastal Central Florida, Central America, and the Caribbean islands which are part of the Neotropical realm, together with South America.Palearctic realm
The Palearctic or Palaearctic is one of the eight biogeographic realms on the Earth's surface, first identified in the 19th century, and still in use today as the basis for zoogeographic classification. The Palearctic is the largest of the eight realms. It stretches across all of Europe, Asia north of the foothills of the Himalayas, North Africa, and the northern and central parts of the Arabian Peninsula.
The realm consists of several ecoregions: the Euro-Siberian region; the Mediterranean Basin; the Sahara and Arabian Deserts; and Western, Central and East Asia. The Palaearctic realm also has numerous rivers and lakes, forming several freshwater ecoregions. Some of the rivers were the source of water for the earliest recorded civilizations that used irrigation methods.Polar climate
The polar climate regions are characterized by a lack of warm summers. Every month in a polar climate has an average temperature of less than 10 °C (50 °F). Regions with polar climate cover more than 20% of the Earth. Most of these regions are far from the equator, and in this case, winter days are extremely short and summer days are extremely long (or lasting for the entirety of each season or longer). A polar climate consists of cool summers and very cold winters, which results in treeless tundra, glaciers, or a permanent or semi-permanent layer of ice.Scotia Sea
The Scotia Sea is a sea located at the northern edge of the Southern Ocean at its boundary with the South Atlantic Ocean. It is bounded on the west by the Drake Passage and on the north, east, and south by the Scotia Arc, an undersea ridge and island arc system supporting various islands. The sea sits atop the Scotia Plate. It is named after the expedition ship Scotia.Toyota Tundra
The Toyota Tundra is a pickup truck manufactured in the United States by the Japanese manufacturer Toyota since May 1999. The Tundra was the first North American full-size pickup to be built by a Japanese manufacturer. The Tundra was nominated for the North American Truck of the Year award and was Motor Trend magazine's Truck of the Year in 2000 and 2008. Initially built in a new Toyota plant in Princeton, Indiana, production was consolidated in 2008 to Toyota's San Antonio, Texas, factory and is the only full-size pickup truck manufactured in Texas.Tundra Publishing
Tundra Publishing was a Northampton, Massachusetts-based comic book publisher founded by Kevin Eastman in 1990. The company was founded to provide a venue for adventurous, creator-owned work by talented cartoonists and illustrators. Its publications were noted in the trade for their high production values, including glossy paper stock, full-color printing, and square binding. Tundra was one of the earlier creator-owned companies, before the formation of Image Comics and Dark Horse Comics' Legends imprint.Creators and projects involved with Tundra included Alan Moore and Bill Sienkiewicz's Big Numbers, Moore & Eddie Campbell's From Hell, Moore & Melinda Gebbie's Lost Girls (these last two original serialised in Stephen R. Bissette's Taboo anthology, which was also part-published by Tundra), The Crow, Mike Allred's Madman and Dave McKean's Cages.Despite its ambitious start, Tundra never became a profitable enterprise. It closed its doors in 1993 after burning through $14 million in three years. Kitchen Sink Press acquired its holdings; it reprinted popular Tundra publications such as Understanding Comics and continued to publish some Tundra series such as Taboo.Tundra shrew
The tundra shrew (Sorex tundrensis) is a small shrew found in Alaska, the northern Yukon Territory, the MacKenzie Delta region of the Northwest Territories, extreme northwestern British Columbia and eastern Russia. At one time, this animal was considered to be a subspecies of the Arctic shrew (Sorex arcticus).
It is dark brown on its back with pale brown sides and grey underparts. Its tail is brown on top and lighter brown below. Its fur grows longer for winter. Its body is about 12 centimetres (4.7 in) in length including a 4 centimetres (1.6 in) long tail. It weighs about 11 grams (0.39 oz).
This animal is found on hillsides with shrubs or grassy vegetation or dry ridges near marshes or bogs. It eats insects, worms and grasses. Predators include hawks and owls. This animal is active day and night year-round, burrowing through the snow in winter. It mates during the spring. 4 to 8 young are born in a nest under a log or in a crevice.Tundra swan
The tundra swan (Cygnus columbianus) is a small Holarctic swan. The two taxa within it are usually regarded as conspecific, but are also sometimes split into two species: Bewick's swan (Cygnus bewickii) of the Palaearctic and the whistling swan (C. columbianus) proper of the Nearctic. Birds from eastern Russia (roughly east of the Taimyr Peninsula) are sometimes separated as the subspecies C. c. jankowskii, but this is not widely accepted as distinct, with most authors including them in C. c. bewickii. Tundra swans are sometimes separated in the subgenus Olor together with the other Arctic swan species.
Bewick's swan was named in 1830 by William Yarrell after the engraver Thomas Bewick, who specialised in illustrations of birds and animals. Cygnus is the Latin for "swan", and columbianus comes from the Columbia River, the type locality.Tundra tire
A tundra tire (UK: tundra tyre) is a large low-pressure tire used on light aircraft to allow operations on rough terrain.A common variant of tundra tire is the bushwheel. These tires include an integral inner tube with the valve manufactured into the side-wall, allowing the tire to operate at very low pressures without risking shearing-off the valve stem and causing a flat tire. Low-pressure tires provide greater cushioning and enable aircraft to land on rough surfaces, unsuitable for normal tires. Bushwheels are a common modification for backcountry aircraft.Tundra vole
The tundra vole (Microtus oeconomus) or root vole is a medium-sized vole found in Northern and Central Europe, Asia, and northwestern North America, including Alaska and northwestern Canada. In the western part of the Netherlands, the tundra vole is a relict from the ice age and has developed to the subspecies Microtus oeconomus arenicola.
It has short ears and a short tail. Its fur is yellowish brown with paler sides and white underparts. They are about 18 cm (7.1 in) long with a 4 cm (1.6 in) tail and weigh about 50 grams (1.8 oz).
This species is found in damp tundra or moist meadows, usually near water. It makes runways through the surface growth in warm weather and tunnels through the snow in winter. It feeds on grasses, sedges and seeds.
Female voles have three to six litters of three to 9 young in a shallow burrow. The vole population in a given area can vary greatly from year to year.
It is active year-round. It also digs underground burrows where it stores seeds and roots, especially licorice root, for the winter. The species epithet oeconomus refers to this "economical" behaviour.West Antarctica
West Antarctica, or Lesser Antarctica, one of the two major regions of Antarctica, is the part of that continent that lies within the Western Hemisphere, and includes the Antarctic Peninsula. It is separated from East Antarctica by the Transantarctic Mountains and is covered by the West Antarctic Ice Sheet. It lies between the Ross Sea (partly covered by the Ross Ice Shelf), and the Weddell Sea (largely covered by the Filchner-Ronne Ice Shelf). It may be considered a giant peninsula stretching from the South Pole towards the tip of South America.
West Antarctica is largely covered by the Antarctic ice sheet, but there have been signs that climate change is having some effect and that this ice sheet may have started to shrink slightly. The coasts of the Antarctic Peninsula are the only parts of West Antarctica that become (in summer) ice-free. These constitute the Marielandia Antarctic tundra and have the warmest climate in Antarctica. The rocks are clad in mosses and lichens that can cope with the intense cold of winter and the short growing-season.