The tundra is a biome (ecologically similar region often referred to as an ecosystem) which consists of the land masses at the very top of the northern hemisphere. Arctic tundra stretches across North America and Eurasia, and it is best known for being extremely cold almost perpetually. Tundra, however, is distinct from pure ice; thus, while the southern hemisphere also boasts huge land masses that are largely barren, these Antarctic conditions do not allow for the albeit minimal seasonal shifts found in a true tundra.
Climate
The tundra is considered to be the coldest of the biomes. Its frigid temperatures are certainly a defining attribute. In the arctic tundra, winter temperatures typically hover around -30 degrees F. However, in the brief summer, which generally lasts between six and ten weeks, temperatures can actually become quite moderate, averaging between the upper 30s and the mid-50s. Tundra is composed of a layer of frozen soil called permafrost, which hinders the development of a wide variety of plant life. During those fleeting weeks of summer, some of the permafrost melts, causing the region to become very marshy as water pools, unable to creep into the ground which, despite the thaw, is still quite hard. However, taking into account melted snow, the tundra receives between 6 and 10 inches of precipitation annually, making it a very dry region for the vast majority of the year.
Flora
Plant diversity in the Arctic tundra is limited due to the severity of the permafrost which covers the ground. Only the top layer of soil is able to thaw in the summer, making it impossible for any plants requiring a deep root structure to grow. Instead, the plants of the Arctic tundra are typically very short shrubs, with few to no trees. In addition to low shrubs, mosses and grasses dominate, as well as a few hundred varieties of flowers.
Fauna
Among the most well-known of the animals that populate the Arctic tundra are the Arctic fox, the snowy owl and the polar bear. Animals of the region are not limited to those with explicit wintry associations, though. Grizzly bears, musk oxen and caribou also can be found, along with a large assortment of other birds and insects.
Alpine Tundra
Not all land included in the tundra biome is found at the highest latitudes. A second variety of tundra is referred to as Alpine tundra, because it is found at the highest regions of the world's mountains. The typical growing season in this type of tundra is about half of the year, much longer than its Arctic counterpart. Still, the frigid climate does not allow large trees to take root, so the plant life consists mainly of dwarf trees, shrubs with small leaves and, again, grasses. Animals native to these high altitudes include sheep, elk, mountain goats and marmots, in addition to several species of insects and a few types of birds.
Future of the Tundra
As global warming becomes increasingly evident, the future of the tundra becomes more uncertain. Scientific research projects that the spread of more woody plants made possible by the increasing temperatures may endanger moss and lichen species in two fifths of the biome in the years to come. The degree to which warming patterns remain the same will determine whether the tundra in its current form will continue into the next century.
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