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Tundra vegetation is composed of dwarf shrubs, sedges, 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. The tundra soil is rich in nitrogen and phosphorus. [2]
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.
The Canadian Arctic tundra is a biogeographic designation for Northern Canada's terrain generally lying north of the tree line or boreal forest, [2] [3] [4] that corresponds with the Scandinavian Alpine tundra to the east and the Siberian Arctic tundra to the west inside the circumpolar tundra belt of the Northern Hemisphere.
Compared to the tundra, boreal forest has a longer and warmer growing season and supports increased species diversity, canopy height, vegetation density, and biomass. Unlike the tundra, which is characterized by a lack of trees and tall vegetation, [45] boreal forests support a number of different tree species. [46]
Ukok Plateau, one of the last remnants of the mammoth steppe [1]. The mammoth steppe, also known as steppe-tundra, was once the Earth's most extensive biome.During glacial periods in the later Pleistocene it stretched east-to-west, from the Iberian Peninsula in the west of Europe, then across Eurasia and through Beringia (the region including the far northeast of Siberia, Alaska and the now ...
In the north, only the hardiest cold-tolerant vascular plants can survive, such as sedge and cotton grass . In a few low-lying, protected areas there can be small stands of Arctic willow ( Salix arctica ), Dryas species, and low-growing purple saxifrage ( Saxifraga oppositifolia ), Kobresia species and arctic poppy ( Papaver radicatum ).
The Arctic tundra now releases more carbon than it naturally draws down from the sky, as wildfires burn down its trees and permafrost thaw releases potent gases from its soil.
This area supports wetland plants especially sedges and grasses, mosses and lichens, and right on the coast there are peat bogs. Trees such as dwarf birch , willows , northern Labrador tea ( Dryas ) and alders grow in the warmer areas of the region, the Mackenzie River delta and the Yukon coast.