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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]
These phenomena contribute to plant diversity by introducing new flora and favoring adaptations, both of new species and the dispersal of pre-existing species. [12] 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 ...
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. [28] The flora is adapted to the harsh conditions of the alpine environment, which include low temperatures, dryness, ultraviolet radiation, and a short growing season.
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.
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]
There are no trees. Vegetation is strongest on the east coast, with the greatest extents towards the south. Plant adaptations required to live in this harsh environment include tolerating cold, long periods of darkness, and precipitation that mostly falls as snow. [5] 50% of the territory is bare rock and ice, or very sparse vegetation. 30% of ...
These complex interactions between plants, animals and abiotic factors in the tundra are held together by the permafrost layer, located 450 metres (1,480 ft) under the soil. [3] However climate change is causing this crucial layer of frozen soil to melt. As a result, tundra communities are becoming unstable and basic processes are breaking down.
This increases their ability to conserve heat. Layers of fat, plumage, and fur also act as insulators to help retain warmth and are common in Arctic animals including polar bears and marine mammals. Some animals also have digestive adaptations to improve their ability to digest woody plants either with or without the aid of microbial organisms.