Animals of tropical deserts and semi-deserts in Australia. Deserts of Australia - the most interesting facts. Need help with a topic

The presence of natural zones on the mainland and their placement directly depend on climatic zones. Based on the fact that Australia is considered the driest continent, it becomes clear that there simply cannot be much diversity here. But on the other hand, the natural zones of Australia have an extremely unique flora and fauna.

Many deserts and few forests

On the smallest continent, zonality is well traced. This is due to the predominantly flat character of the relief. The natural zones of Australia gradually replace each other in the meridional direction following the change in temperature and rainfall.

The southern tropic crosses the mainland almost in the middle, and most of its territory is located in a hot tropical climate zone, which makes the climate arid. In terms of the amount of annual precipitation, Australia is among all the continents in last place. Most of its territory receives only 250 mm of precipitation during the year. In many parts of the continent, not a drop of rain falls for several years.

Australia, whose natural zones divide the continent into three parts, has several zones in the east and west, stretched along the coast, where the amount of precipitation is noticeably greater. The mainland is in first place in terms of the relative area of ​​desert regions and in last place in terms of forest area. In addition, only 2% of Australia's forests are of industrial importance.

Features of natural areas

Savannahs and light forests are located in the subequatorial climatic zone. The vegetation is dominated by herbs, among which acacias, eucalyptus, bottle trees grow.

In the east of the mainland, in conditions of sufficient moisture, there are such natural areas of Australia as humid tropical forests. Among palms, ficuses and tree ferns marsupial anteaters, wombats, kangaroos live.

The natural areas of Australia differ from similar areas on other continents. For example, semi-deserts and tropical deserts occupy vast areas on the mainland - almost 44% of its territory. In the Australian deserts, you can find unusual thickets of dry thorny bushes called scrubs. Parts of the semi-desert, overgrown with hard grasses and shrubs, are used as pastures for sheep. There are also large sandy deserts, which differ from the deserts of other continents in that they do not have oases.

In the southeastern part and in the southwest of the continent there are subtropical forests in which eucalyptus and evergreen beech grow.

The peculiarity of the organic world

Flora of Australia, due to long isolation from other continents, has a large number of endemic plants. Almost 75% of them can be seen only here and nowhere else. More than 600 eucalyptus species, 490 acacia species and 25 casaurine species are found on the mainland.

The animal world is even more peculiar. Almost 90% of animals are endemic. Only in Australia you can find mammals that disappeared on other continents a long time ago, for example, echidna and platypus - ancient primitive animals.

Actual

Miscellaneous
Miscellaneous

The most arid central regions of the mainland occupy the largest areas of Australia. Here are various types of territories, from loose sands, salt marshes, rubble rocky areas to spiny forests. However, two groups dominate: 1) the acacia mulga-scrub formation; 2) a formation dominated by spinifex grass, or triodnium. The latter dominates in the most deserted central regions.

Acacia shrub and stunted (3-5 m) tree-shrub deserts and semi-deserts are similar in nature to the dry prickly woodlands of Somalia or the Kalahari on the African continent. The northern variants of these groups with a short summer wet period and an abundance of tall termite mounds can also be considered as the extreme arid version of the savanna and light forest zone. The dominant plant almost everywhere is ours - veinless acacia - and other phyllodes. The number of eucalyptus and casuarina is small, they are confined to dry riverbeds and extensive depressions with a close occurrence of groundwater. The grass cover is often almost absent or represented by very sparse groups of grasses, saltworts, and other leafy succulents.

The sandy areas in the center and west of the continent are covered with thickets of extremely xeromorphic hard grasses from the genus triodia. In Queensland and New South Wales, prickly pear cactus has proliferated and become a noxious weed. Prickly pear was brought from South America in the 80s of the last century and settled on an area of ​​about 24 million hectares.

Unlike the Sahara and the Namib, in the deserts of Australia there are no significant areas of "absolute" deserts, practically free from higher plants. In drainless basins and along the shores of salt lakes, halophytic formations are developed, formed by special species of widespread ancient genera (saltwort, quinoa, parnolistnik, prutnyak, saltpeter). Shober's saltpeter also grows in the semi-deserts of Eurasia. The Nullarbor Plain adjoining the Great Australian Bight has semi-desert vegetation, already developing in a subtropical, close to temperate climate. It is dominated by high (up to 1.5 m) bushes of various halophytes - representatives of haze (hospice, quinoa, etc.), which are considered a good fodder plant for sheep. On the plain, due to the wide distribution of karst phenomena, there are almost no surface water bodies.

Some botanists believe that real deserts in Australia are almost never found, and semi-deserts predominate. Indeed, the density of vegetation in the arid regions of the mainland is usually relatively large, which is associated with a regular short wet season. The annual amount of precipitation is nowhere below 100 mm, but usually it is close to 200-300 mm. In addition, in many places there is a shallow water-resistant horizon, where the moisture available to the roots of plants is stored for a long time.

Animal world. In the faunistic aspect, the fauna of the arid interior regions of Australia as a whole is a depleted variant of dry savanna and light forest groups. Most of the species are found both in deserts and savannahs, although a number of groups of animals are especially numerous in desert and semi-desert habitats. Of the mammals, such typical animals include the marsupial mole, the marsupial jerboa, comb-tailed marsupial mice and the comb-tailed marsupial rat. The entire central and western parts of the mainland are inhabited by large red kangaroos. These animals are numerous in many places and are considered undesirable competitors of sheep. The same applies to smaller types of wallabies. Of the smallest species of the kangaroo family (less than a rabbit), kangaroo rats are interesting for their ability to carry a "load" - an armful of grass, clasping it with their long tail. Many species of kangaroo rats widely inhabited almost the entire continent, but are now heavily exterminated by introduced dogs and foxes, and are also being displaced by rabbits, which inhabit and destroy their original habitats. Therefore, now they are better preserved precisely in desert regions, where the influence of introduced animals is less felt. Here the most common dog is the dingo. In some areas, feral one-humped camels bred, brought to the mainland in the last century as a vehicle on expeditions.

The most famous bird of the semi-desert regions of the mainland is the emu. This is the only species (sometimes two closely related species are distinguished) of a special family related to cassowaries. In all arid regions, weavers and small parrots are common, feeding on seeds of cereals (including triodia). These are the already mentioned zebra finches, budgerigars, and also nymph parrots. All these species nest in the hollows of dry trees. The nocturnal parrot is very typical for arid regions. It is indeed a nocturnal bird. Most of the time she spends on the ground, the basis of nutrition is the seeds of the trio. Unlike most other parrots, the nocturnal one does not nest in hollows, but among thickets of prickly grasses.

Of the vertebrates, various reptiles are especially characteristic of the desert and semi-desert, of which lizards of the agamic, skink and monitor lizard families predominate. The scale-legged family characteristic of Australia, which includes snake-like lizards with reduced limbs, also has desert representatives. Among the agamas in the tropical northern regions of dry woodlands and semi-deserts, there are frilled lizards, which are also characteristic of the savannah. Species of this genus have the ability to run on two hind limbs. This way of movement was inherent in some Mesozoic dinosaurs. Several species of bearded lizards, similar to our common dragons, live in the deserts. The most original appearance of Moloch. This small, up to 20 cm, flat lizard is covered with outgrowths and spikes. Moloch's skin can absorb moisture. In lifestyle and appearance, it resembles American desert toad lizards. The basis of nutrition of Moloch is ants.

Skinks are represented mainly by genera endemic to Australia (sometimes including New Zealand), whose species live both in deserts and in other zones. There are especially many species of the endemic genus Ctenotus - small graceful lizards with smooth scales.

Australia is located in the southern and eastern hemispheres of the planet. The world's smallest continent occupies only 5% of the Earth's land mass. The area of ​​the continent with the islands is 7,692,024 km². The length from north to south is 3.7 thousand km, and from west to east - about 4 thousand km.

The coastline stretches for 35,877 km and is slightly indented. The waters of the Gulf of Carpentaria protrude into the territory of the northern coast of the continent, and the Cape York Peninsula protrudes noticeably against the background of the main coastline. The main bays are located in the southeast of Australia.

The most extreme points of the continent include:

• in the north - Cape York, washed by the waters of the Coral and Arafura Seas;
• in the south - Cape Saunt Point, washed by the waters of the Tasman Sea;
• in the west - Cape Steep Point, washed by the waters of the Indian Ocean;
• in the east - Cape Byron, washed by the waters of the Tasman Sea.

The largest island belonging to Australia is Tasmania. Its total area is 68,401 km². Off the northern coast are Groote Island, Melville and Bathurst, as well as the large Derk Hartog Islands to the west and Fraser Island to the east. Within the mainland shallows are the islands of Kangaroo, King and Flinders.

The Great Barrier Reef is a priceless natural monument located along the northeast line of the continent. It includes clusters of small underwater and surface islands, as well as coral reefs. Its length will be more than 2000 km.

In the north, west and south, Australia is washed by the Indian Ocean, and in the east by the Pacific Ocean. In addition, the continent is washed by the waters of four seas: Timor or Orange, Arafura, Tasmanovo and Coral, which attract tourists from all over the world all year round.

Relief

Blue Mountains, Australia

The relief of Australia is dominated by flat areas. Mount Kosciuszko, 2228 m above sea level, is the highest point of the continent. The average height on the continent is 215 m. The Australian platform, which was once part of the ancient continent of Gondwana, is the foundation of the continent today. The basement area is covered by strata of marine and continental sedimentary rocks.

The modern relief includes the Western Australian Plateau, the Central Lowlands and the East Australian Mountains. As a result of the uplift and subsidence of the earth's crust, a trough filled with sedimentary rocks formed in the east of the Australian Platform. A large watershed range is located in the eastern part of the mainland. The mountains formed in have collapsed over time. Only the Australian Alps exceed the 2,000 mark. This is the only place on the continent where there is snow in places in shaded gorges.

There are no active volcanoes and earthquakes on the mainland. It is located in the center of the Australian plate, which saved it from seismically active faults at the boundaries of tectonic plates.

desert

Great Sandy Desert in Australia

Australia is the driest continent on earth. Desert zones make up 44% of the entire region. They are mainly located in the northwest of the continent. The largest deserts in Australia are listed below:

Great Victoria Desert

The largest area, which occupies 4% of the total area of ​​the continent. Named after the British Queen. Part of the territory belongs to the natives. Agricultural activity is not possible due to lack of water.

Great sandy desert

It occupies an area equal to Japan. Due to the peculiarities of the climate, the sand forms high dunes. There is no permanent population. Precipitation does not fall every year, and there are no reservoirs.

Tanami Desert

A little-studied area in the north of the continent. There are shallow water basins, precipitation falls periodically. But due to high temperatures, moisture evaporates very quickly. There is gold mining in the desert.

Simpson Desert

The scarlet sands that roll over the area are famous among tourists. The region is named after an English geographer. In the 20th century, they searched for oil here to no avail. Today, the desert is popular with off-road enthusiasts.

Gibson Desert

Situated between the Great Sandy Desert and the Victorian Desert. There are several saline lakes on the territory. The state has created a reserve here for animals adapted to severe climatic conditions.

Small sandy desert

There are several lakes in the area. The biggest one is Disappointment. The water in it is unsuitable for drinking and household needs, although this did not prevent the natives from settling in the desert.

Desert Strzelecki

Named after the Polish explorer. Around the desert there are several villages whose population is engaged in agriculture. On the very territory there is a national park that offers entertainment for fans of extreme tourism.

Inland waters

The main river system on the continent is the Murray River and its tributaries: the Darling, the Murrumbidgee and the Goulburn. The total area is over 1 million km². Due to low rainfall, most rivers dry up. The springs originating in the mountains of Eastern Australia and the rivers of Tasmania have a permanent outflow.

The largest lakes: Eyre, Gairdner, Frome and Torrens are located in the south. Most of the time they are pits covered with salt-bearing clays. On the southeast coast there are numerous lagoons separated by shallows from the sea. Freshwater lakes are located on the island of Tasmania. Great Lake is exploited for hydrotechnical purposes.

Australia has large reserves of artesian water. The total reserves of freshwater underground sources are about 3240 thousand km². However, they are deep, warm and often saline. The water is suitable for watering livestock, but unsuitable for domestic use due to its high mineral content. The large Artesian basin occupies 1751.5 thousand km². The development of agriculture on the mainland depends on it.

Climate

The continent is located in three climatic zones:

Tasmania is in a temperate climate. Since Australia is located south of the line, winter starts from June and summer from December. There are no sudden temperature changes or extreme weather conditions. From May to October it is always sunny, the air humidity is 30%. The average temperature in winter is usually not lower than 13º C. A cold winter is considered when the thermometer drops to zero. Summer is a period of cyclones and thunderstorms, the air warms up to 29º C. On the southeast coast, the climate resembles. The coldest region of Australia is Tasmania. In winter, frosts occur there. In the central regions of the continent, slight temperature differences are observed.

Flora and fauna:

Vegetable world

The flora is quite peculiar and endemic, since Australia is located at a considerable distance from the rest of the continents. The climate is characterized by a sharp aridity, because of this, exceptionally viable plants dominate in nature. Trees have a powerful root system, which is adapted to suck water from a depth of up to 30 meters. In some plant species, the leaves are hard, leathery and turn away from the sun to avoid excessive evaporation. Eucalyptus, bottle tree, palms and ficuses dominate.

Represented by acacia and soddy cereals. In places where there is a lot of precipitation, the same eucalyptus trees grow, but accompanied by horsetails and ferns, as well as other plants characteristic of the Mediterranean climate. continents are small. The total area of ​​green areas is 5% of the territory of Australia, including artificial plantations of pine and other softwoods. The colonists brought in European species of trees, herbs and shrubs. Grapes and cotton have taken root well, as well as fruit trees and vegetables. Corn, rye, oats, wheat and barley grow well on Australian soil.

Animal world

Since Australia was discovered later than other continents and developed separately, it is home to animals that are unique and are not found anywhere else in the world. There are practically no ruminants, ungulates and monkeys on the mainland. But there are a lot of representatives of marsupials: kangaroo; marsupial squirrel; ant-eater; Tasmanian devil; marsupial mouse. In total there are about 250 species. There are many bizarre animals: echidna, koala, platypus, frilled lizards. Among the unusual birds include lyrebirds and emus. By the number of dangerous representatives of the fauna of Australia, you can give the palm. It is better to stay away from the wild dog Dingo, cassowary, reptiles and spiders. The most dangerous animal, oddly enough, is considered a mosquito from the genus Kusaki. He is a carrier of dangerous diseases. Marine animals are also dangerous. Species of sharks, jellyfish and octopuses can pose a serious threat to people resting on the coast.

Minerals

The main wealth of the continent is considered, the potential of which is 20% higher than in the rest of the world. Australia has a lot of bauxite. Since the second half of the XX century. began mining iron ore. In the west are deposits of polymetals. Gold is mined in the southwest of the mainland. Scientists have established that there are deposits of natural gas and oil in the bowels. Research is currently underway.

Ecological situation

The country's economy is kept in high positions due to the extraction of minerals. Mining depletes the subsoil and destroys the topsoil. Because of this, the area under agriculture is shrinking. Chronic water shortages have forced the government to create a series of bans. At certain times of the year, people are not allowed to water lawns, wash cars, or fill swimming pools.
During the Cold War, nuclear tests were carried out on the territory of the country. This negatively affected the radiation situation. Maraling, the area where the tests were carried out, is still considered contaminated.

Modern uranium springs are close to Spencer Gulf and Kakadu National Park. This worries the public: the precedent, when dirty water was poured into the reserve, has already been created. Aboriginal life depends on natural factors. As a result of the desertification of the continent, they have to leave their inhabited settlements forever. The state and world-famous public organizations are making every effort to preserve the unique Australia and its. New nature reserves and national parks are being created.

Population

The first generation of colonists arrived on the mainland in 1788. At that time, Australia was a place of exile for lawbreakers. The number of the first settlers was just over a thousand people. As a result of forced immigration, the number of people has increased significantly. Australia ceased to be a place of exile for convicts in 1868. The influx of voluntary colonialists is associated with the development of cattle breeding and the discovery of mines.

Modern society does not remind of the difficult years of development and formation of the country. The population is 24.5 million people. In terms of population, the country ranks 50th in the world. The number of aborigines is 2.7%. Migrants most often have British, German, New Zealand, Italian and Filipino roots. There are a large number of confessions in the country. The official language is Australian English. It is used by 80% of the population.

Population density differ in different regions. On average, no more than three people live per square kilometer. The southeastern coast of the mainland is most densely populated. Australia has a high life expectancy of the population, on average about eighty years. The process of rapid aging due to low birth rates, as in Europe, is not observed. Australians are still among the young nations.

About 3.8 million sq. km of the surface of Australia (44%) is occupied by arid territories, of which 1.7 million square meters. km - desert. This allows us to say that Australia is the most arid continent on the globe.

The deserts of Australia are confined to ancient structural elevated plains. The climatic conditions of Australia are determined by its geographical position, orographic features, the vast water area of ​​the Pacific Ocean and the proximity of the Asian mainland. Of the three climatic zones of the southern hemisphere, the deserts of Australia are located in two: tropical and subtropical, with most of them occupied by the latter zone.

In the tropical climate zone, which occupies the territory between the 20th and 30th parallels in the desert zone, a tropical continental desert climate is formed. The subtropical continental climate is common in the southern part of Australia, adjacent to the Great Australian Bight. These are the outskirts of the Great Victoria Desert. Therefore, in the summer period, from December to February, the average temperatures reach 30 ° C, and sometimes even higher, and in the winter (July - August) they decrease to an average of 15-18 ° C. In some years, the entire summer period temperatures can reach 40 ° C, and winter nights in the neighborhood of the tropics drops to 0 ° C and below. The amount and territorial distribution of precipitation is determined by the direction and nature of the winds.

The main source of moisture is the "dry" southeast trade winds, since most of the moisture is retained by the mountain ranges of Eastern Australia. The central and western parts of the country, corresponding to about half of the area, receive an average of about 250-300 mm of precipitation per year. The Simpson Desert receives the least amount of precipitation, from 100 to 150 mm per year. The rainy season in the northern half of the continent, where the monsoon change of winds dominates, is confined to the summer period, and, in its southern part, arid conditions prevail during this period. It should be noted that the amount of winter precipitation in the southern half decreases as one moves inland, rarely reaching 28°S. In turn, summer precipitation in the northern half, having the same tendency, does not spread south of the tropic. Thus, in the zone between the tropic and 28°S. there is a dry zone.

Australia is characterized by excessive variability in average annual precipitation and uneven precipitation throughout the year. The presence of long dry periods and high average annual temperatures prevailing over a large part of the continent cause high annual evaporation rates. In the central part of the mainland, they are 2000-2200 mm, decreasing towards its marginal parts. The surface waters of the mainland are extremely poor and extremely unevenly distributed over the territory. This is especially true for the desert western and central regions of Australia, which are practically drainless, but make up 50% of the continent's area.

The hydrographic network of Australia is represented by temporary drying watercourses (creeks). The drainage of the rivers of the deserts of Australia belongs partly to the basin of the Indian Ocean and the basin of Lake Eyre. The hydrographic network of the mainland is supplemented by lakes, of which there are about 800, and a significant part of them are located in deserts. The largest lakes - Eyre, Torrens, Carnegie and others - are salt marshes or dried-up basins covered with a powerful layer of salts. The lack of surface water is compensated by the richness of groundwater. A number of large artesian basins stand out here (Desert Artesian Basin, Northwest Basin, Northern Murray River Basin and part of Australia's largest groundwater basin, the Great Artesian Basin).

The soil cover of deserts is very peculiar. In the northern and central regions, red, red-brown and brown soils are distinguished (characteristic features of these soils are an acid reaction, coloring with iron oxides). Serozem-like soils are widespread in the southern parts of Australia. In western Australia, desert soils are found along the outskirts of drainless basins. The Great Sandy Desert and the Great Victoria Desert are characterized by red sandy desert soils. Salt marshes and solonetzes are widely developed in drainless internal depressions in the southwest of Australia and in the basin of Lake Eyre.

The Australian deserts are divided into many different types in terms of landscape, among which Australian scientists most often distinguish mountainous and foothill deserts, structural plains deserts, rocky deserts, sandy deserts, clay deserts, plains. Sandy deserts are the most common, occupying about 32% of the continent's area. Along with sandy deserts, rocky deserts are also widespread (they occupy about 13% of the area of ​​arid territories. Piedmont plains are an alternation of large rocky deserts with dry channels of small rivers. This type of desert is the source of most of the country's desert watercourses and always serves as a habitat for aborigines. Deserts Structural plains are found in the form of a plateau with a height of no more than 600 m above sea level.After sandy deserts, they are the most developed, occupying 23% of the area of ​​arid territories, confined mainly to Western Australia.