An Arctic–alpine

taxon In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

is one whose natural

distribution Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations * Probability distribution, the probability of a particular value or value range of a vari ...

includes the

Arctic The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...

and more southerly mountain ranges, particularly the

Alps The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Sw ...

. The presence of identical or similar taxa in both the

tundra In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless moun ...

of the far north, and high

mountain range A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have arise ...

s much further south is testament to the similar environmental conditions found in the two locations. Arctic–alpine plants, for instance, must be

adapted In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...

to the low temperatures, extremes of temperature, strong winds and short growing season; they are therefore typically low-growing and often form mats or

cushions A cushion is a soft bag of some ornamental material, usually stuffed with wool, hair, feathers, polyester staple fiber, non-woven material, cotton, or even paper torn into fragments. It may be used for sitting or kneeling upon, or to soften th ...

to reduce water loss through

evapotranspiration Evapotranspiration (ET) is the combined processes by which water moves from the earth’s surface into the atmosphere. It covers both water evaporation (movement of water to the air directly from soil, canopies, and water bodies) and transpi ...

. It is often assumed that an organism which currently has an Arctic–alpine distribution was, during colder periods of the

Earth's history The history of Earth concerns the development of planet Earth from its formation to the present day. Nearly all branches of natural science have contributed to understanding of the main events of Earth's past, characterized by constant geologic ...

(such as during the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betw ...

s), widespread across the area between the Arctic and the Alps. This is known from

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

records to be true for ''

Dryas octopetala ''Dryas octopetala'', the mountain avens, eightpetal mountain-avens, white dryas or white dryad, is an Arctic–alpine flowering plant in the family Rosaceae. It is a small prostrate evergreen subshrub forming large colonies. The specific epithet ...

'', for instance. In other cases, the disjunct distribution may be the result of

long-distance dispersal Biological dispersal refers to both the movement of individuals (animals, plants, fungi, bacteria, etc.) from their birth site to their breeding site ('natal dispersal'), as well as the movement from one breeding site to another ('breeding dis ...

. Examples of Arctic–alpine plants include: *'' Arabis alpina'' *''

Betula nana ''Betula nana'', the dwarf birch, is a species of birch in the family Betulaceae, found mainly in the tundra of the Arctic region. Description It is a monoecious, deciduous shrub growing up to high. The bark is non-peeling and shiny red-copper ...

'' *''

Draba incana ''Draba incana'' is a species of flowering plant belonging to the family Brassicaceae. Its native range is Canada to Northern Central and Northeastern USA, Greenland, Northern Europe, Alps, Pyrenees The Pyrenees (; es, Pirineos ; french: Pyré ...

'' *''

Gagea serotina ''Gagea serotina'', synonym ''Lloydia serotina'', is an Arctic–alpine flowering plant of the lily family. It is widespread across the mountainous parts of western North America, from Alaska to New Mexico, and in Europe is found in the Alps an ...

'' (syn. ''Lloydia serotina'') *''

Loiseleuria procumbens ''Kalmia procumbens'', commonly known as alpine azalea or trailing azalea, is a dwarf shrub of high mountain regions of the Northern Hemisphere that usually grows no more than tall. Originally named by Linnaeus as ''Azalea procumbens'', it is al ...

'' *''

Micranthes stellaris ''Micranthes stellaris'', synonym ''Saxifraga stellaris'', the starry saxifrage or hairy kidney-wort, is an Arctic–alpine species in the family Saxifragaceae. It produces panicles of 5–10 white flowers on a stem up to tall, rising from a ba ...

'' *''

Oxyria digyna ''Oxyria digyna'' (mountain sorrel, wood sorrel, Alpine sorrel or Alpine mountain-sorrel) is a species of flowering plant in the buckwheat family (Polygonaceae).Sierra Nevada Wildflowers, Karen Wiese, 2nd ed., 2013, p. 108 It is native to arctic ...

'' *'' Ranunculus glacialis'' *''

Salix herbacea ''Salix herbacea'', the dwarf willow, least willow or snowbed willow, is a species of tiny creeping willow (family Salicaceae) adapted to survive in harsh arctic and subarctic environments. Distributed widely in alpine and arctic environments ar ...

'' *''

Saussurea alpina ''Saussurea alpina'' is a species of flowering plant belonging to the family Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Aster ...

'' *''

Saxifraga oppositifolia ''Saxifraga oppositifolia'', the purple saxifrage or purple mountain saxifrage, is a species of plant that is very common in the high Arctic and also some high mountainous areas further south, including northern Great Britain, Britain, the Alps ...

'' *''

Silene acaulis ''Silene acaulis'', known as moss campion or cushion pink, is a small mountain-dwelling wildflower that is common all over the high arctic and tundra and in high mountains of Eurasia and North America (Alps, Carpathians, southern Siberia, Pyrenee ...

'' *'' Thalictrum alpinum'' *''

Veronica alpina ''Veronica alpina'', the alpine speedwell or alpine veronica, is a species of flowering plant in the genus '' Veronica'', native to Canada, Greenland, Iceland, the Faroes, Svalbard, most of Europe, parts of Siberia, northern Pakistan, the western ...

References

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