The planet is heated unevenly, soits surface is a lot of different climatic zones, which form natural zones. One of them is the desert. It has a sparse flora or is generally characterized by its absence. There are several types of deserts:
- sandy;
- saline soils;
- stony;
- clayey.
A separate category is the Arctic desert, that is, the territories of the Arctic and Antarctica. The lands of these zones may or may not have snow cover.
Dry valleys of McMurdo
This snow-white dry desert of Antarctica.These are Antarctic oases on the Land of Victoria. The total occupied area is 8 thousand square kilometers, on which there is no ice. This is the driest place on the whole planet, where rain and snow have not been falling for more than 2 million years. It is believed that this place maximally reflects the natural conditions of the planet Mars. In the desert, frequent catabatic winds, that is, reaching 320 kilometers per hour, which cause evaporation of moisture. In winter, the air temperature drops to -50 ° C.
Despite such harsh conditions, thisthe plant managed to find endolith plants. And there are no animals in the desert. The researchers found only endolytic bacteria that live on the so-called Bloody waterfall. From the dry air they are protected by relatively wet rocks. With the onset of summer heat, bacteria are selected outside, because of this place and called the Red Waterfall. And their color is associated with a diet based solely on sulfur and iron.
Arctic
The desert zone of the Arctic stretches from the NorthAmerica to Asia. The climate here is quite severe - in some places the atmospheric temperature can reach -50 ° C with a low amount of precipitation. Vegetation is scant. We will call the animals of the arctic deserts:
- The pink seagull. A fairly large bird, in weight can reach 250 grams, with a body of 35 centimeters. Well tolerates severe winters.
- Narwhal. It is related to the genus of cetaceans, has a horn that protrudes from the mouth, although it is inherently an ordinary tooth. This tooth can grow up to 3 meters in length.
- Seal. It is in the Arctic that you can find several species of this ancient and amazing animal: the Greenland, the sea hare and the ordinary seal.
- Walrus. The closest relative of the seals. It has a giant size - up to 3 meters in height, with a weight of about 1 ton. Is a predator.
- Polar bear.One of the largest land predators on the whole planet. The height can reach 2.5 meters, with a weight of 500 kg. It attacks almost everyone, even large animals, on seals and walruses.
Sahara
The most famous and largest sand desert onthe whole planet. The total area occupied is about 9 million m². On this territory the world's fiercest is hotter. Sometimes the air temperature reaches +57 ° С. In this case, there are constant torrential rains, but often there are sandstorms, in which sand can rise to 1000 m in height.
The animal world of the Sahara desert is very diverse,despite the harsh living conditions. Therefore, these representatives of the fauna can be called the most interesting on the planet, and they are very rarely found in other parts of the globe:
- Horned viper.The poison of this reptile is so dangerous that it causes irreparable damage to the blood cells of the victim. As a rule, a meeting with her ends with a lethal outcome, although this desert animal is attributed to endangered species.
- Dromedary, or one-humped camel. Today it is present exclusively in households. Very hardy and strong animal, capable of a long time without water.
- Gazelle Dorkas. Very fast (in the race reaches 80 km / h) and light animal (average body weight - 25 kg). It has a sandy color that allows an artiodactual to hide among the dunes.
- Beetle, or scarab. Once was considered sacred. It feeds on manure of the desert artiodactyls. Finding a litter, rolls it into the underground voids with its back legs, where it eats.
- Yellow Scorpion.Insect venom rarely causes health problems in adults, but for old people and children it can be fatal. This is a very small animal with very poisonous neurotoxins.
Semi-deserts
Such territories are also called the desert steppe.It is a cross between savannahs and deserts, which are located in the temperate geographic zone. In such a desert, animals and plants are more diverse. There are no forests here yet, but there is a specific ground cover. The average temperature here is from +20 ° С to +25 ° С, and in tropical parts of the Earth it reaches +30 ° С. Semi-deserts on the planet have many similarities, but also differences depending on the belt.
Temperate zone
This is a strip 500 kilometers from the Caspianlowland to south america. Territories in Eurasia differ from locations in North and South America in atmospheric temperatures. In Eurasia, in winter, it can drop to -20 ° C. The soil can be described as salted, brown and light chestnut. Towards the south there are more signs of real desert.
For the animal world, semi-deserts of Russia have gazelles, gazelles, viskachi, and beauty bustards. In South and North America there are lizards, turtles, saigas and snakes.
Subtropics
Such a natural area is located on the slopes of the plateau, uplands and plateaus. These are the Armenian Highlands, the Anatolian Plateau, the Valley of the Rocky Mountains, Karru and Flieders, etc.
The fauna of the desert in the subtropics is different fromtemperate areas. The porcupine, the cheetah, the striped hyena and the Mediterranean viper live here. It is in the subtropical deserts you can see a cobra, sandy efu and kulans. Termites play a huge role in the ecosystem.
Tropics
Пустыни этой зоны занимают самую большую the territory of the African continent. It is a semi-desert Sahel, located in the south of the Sahara desert and is the northern part of Burkina Faso. The climate here is quite dry and hot. There are few vegetation on the semi-desert territory, there are fragments of light forests and single acacia trees twisted or red.
Once upon a time a huge number lived here.animals of tropical deserts - mainly artiodactyls. These were gazelles and saber-legged antelopes, as well as kononi antelopes. There were a lot of herbivorous representatives of the fauna and predators, including even a hyenoid dog, cheetah and lion. Birds chose wetlands as nesting sites.
Today in semi-desert a real ecological catastrophe is brewing, one can say that the natural balance has already been completely disturbed.
One of the first reasons is deforestation, althoughIt is difficult to imagine such a problem for the semi-desert. Nevertheless, the locals use most of the vegetation as complementary food for domestic cattle, while at the same time depriving wild ungulates from subsistence.
Locals use as a typefarming slash-and-burn method. If we use this technique for several years in a row, then the ground becomes barren for 15 or even 20 years.
But the most dangerous that rare vegetationsemi-desert is used to make fuel. Due to these reasons, these spaces are becoming poorer every year, droughts are becoming more frequent and unique animals disappear.
Desert and semi-desert animals have not disappeared sincefaces of the earth for the reason that most of the territories are located sufficiently remote from a person. We are obliged to take care of our smaller brothers, carry out sand control measures on a regular basis and engage in gardening of the border zones.
