Arctic deserts

The extreme north of Asia and North America occupyArctic deserts are lifeless spaces with extremely sparse vegetation, located among the snows and ice. These landscapes are characteristic for most of the territory of Greenland, for the Canadian Arctic archipelago, as well as other islands of the Arctic basin and islands located off the coast of Antarctica.

The climate of this natural zone is arctic,cold. Winter here is long and severe (average temperature is -10 to -35 ° C), and summer is short and cold (0 ... + 5 ° C). In winter, a polar night, which, depending on the latitude of the area, continues from 98 days to six months. In June, simultaneously with the onset of the polar day, the arctic deserts slowly come to life - spring comes. Despite the fact that the sun shines around the clock, the ground thaws only a few centimeters. During that short period during which positive temperatures are kept, snow falls only on small areas with swampy and stony soils.

In the summer, the sky is very rare; asNormally, it is covered with clouds, giving a long rainfall (rain, often with snow). During this period, the earth is often enveloped in thick fogs, formed due to the evaporation of moisture from the surface of the ocean. Virtually all of the atmospheric moisture remains on the surface, not evaporating due to the low position of the sun and low temperatures, and not percolating into the frozen ground.

Scale mosses are characteristic for this natural zone,lichens, as well as herbaceous vegetation, adapted to life in the north. Plots covered with vegetation are a kind of oasis among polar glaciers and snows, animating arctic deserts. Here there are representatives of flowering plants: saxifrage, shrimp and some other cereals, buttercup, polar poppy, cowberry, sedge. No shrubs, and lichens, mosses and grassy species of continuous cover do not form. The height of the plants rarely exceeds 10 cm, since the cold Arctic air is heated from the ground, and the bottom is relatively warm. Fleeing from the wind, plants are pressed against the rocks and settle in depressions, from the leeward side of the rocks and other elevations of the relief, on the slopes of the southern exposition.

The terrestrial fauna of this natural zone is extremely poor. Here live Arctic Foxes, lemmings, polar bears. In the summer, there are "bird markets": the eiders, the guillemot, the kulik, the kittiwake, the foolish, the bush, the goose and other species come and nest. The marine fauna is more abundant.

The Arctic arctic zone of Russia in the south reachesthe latitude of Wrangel Island, and in the north it is limited to the islands of Franz Josef Land. It covers the Land of Franz Josef, the New Earth (the northern island), the Novosibirsk Islands, the Northern Earth, the Wrangel Island, the northern part of the Taimyr Peninsula and the Arctic seas washing these parts of the land. The coastal zones of most of the islands are flat lowlands, and inland areas are mountain ranges up to 1000 m high and table tops. The snow line in these latitudes is located low, so a significant part of many islands are occupied by glaciers (up to 85% on Franz Josef Land). In some places, the continental glaciers slide to the sea and break off, forming icebergs. Permafrost soils are common on land areas free from ice.

Permafrost, cold and short summer andscant vegetation create unfavorable conditions for the soil-forming process. Therefore, the soils in the territory of this natural zone are low-power, stony, poor.

However, despite the extreme depletionsoil and vegetation cover, the Arctic deserts of Russia are characterized by a change in species composition in the latitudinal direction. Grass-moss communities are typical for the north of the zone, which are replaced by depleted shrubby-mossy to the south. In the extreme south, the same arctic deserts of shrubby-moss type are widespread, but already with a pronounced shrub layer.