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Arctic vegetation is largely controlled by the mean temperature in July, the warmest month. Arctic vegetation occurs in the tundra climate, where trees cannot grow.Tundra climate has two boundaries: the snow line, where permanent year-round snow and ice are on the ground, and the tree line, where the climate becomes warm enough for trees to grow. [7]
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. [9] There are also a few fish species. There are few species with large populations.
The tundra is an extremely harsh, cold, windy, and unique ecosystem found on the extreme north and south latitudes of our Earth. The soil consists mostly of frozen permafrost, which makes it difficult for extended root systems to grow, and water to drain and support a wide variety of plant life.
Though tundra covers only a minority of the Earth's surface (17-20%), the biodiversity of plant species is important to human nutrition. Of the 20 plant species that make up 80% of human food, 7 of them (35%) originated in this region. [13] Alpine flora at 11,500 feet (3500 m) on the Flat Tops plateau in the Colorado Rocky Mountains U.S.A
Plant species supported by tundra are generally short, lacking stems due to threats posed to vascular structure by frozen temperatures, and much of their growing matter is found below the soil. [44] They are composed mainly of perennial forbs, dwarf shrubs, grasses, lichens, and mosses. [42] [45]
Alpine plants can exist at very high elevations, from 300 to 6,000 metres (1,000 to 20,000 ft), depending on location. [8] [9] For example, there is a moss that grows at 6,480 m (21,260 ft) on Mount Everest. [9] Arenaria bryophylla is the highest flowering plant in the world, occurring as high as 6,180 m (20,280 ft). [10]
[15] There are three types of tundra: Arctic tundra, [16] alpine tundra, [16] and Antarctic tundra [17] In tundra, the vegetation is composed of dwarf shrubs, sedges and grasses, mosses, and lichens. Scattered trees grow in some tundra. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or ...
Terrestrial ecosystems occupy 55,660,000 mi 2 (144,150,000 km 2), or 28.26% of Earth's surface. [5] Major plant taxa in terrestrial ecosystems are members of the division Magnoliophyta (flowering plants), of which there are about 275,000 species, and the division Pinophyta (conifers), of which there are about 500 species.