Report on the islands of Oceania. Peculiarities of the nature of Oceania. Great Barrier Reef

Oceania is the largest collection of islands, located in the central and western parts of the Pacific Ocean (see Fig. 1).

About 10 thousand islands of Oceania are scattered over a vast territory from the subtropical latitudes of the Northern Hemisphere to the temperate latitudes of the Southern Hemisphere. Most of the islands are grouped into archipelagos: New Zealand, Hawaii, Fiji, Tuamotu, etc. This location plays an important role for the nature of the islands.

Oceania is divided into three parts: Melanesia (translated from Greek as “Black Islands”), Micronesia (“small islands”), Polynesia (“Many Islands”).

Rice. 1. Map of Oceania

Islands and their origin

Origin, geographical position and the size of the islands of Oceania is closely related to the structure of the Pacific Ocean floor. They are a surface reflection of the underwater oceanic relief, because the islands have their foundations on the ocean floor.

The islands of Oceania have different origins: continental, volcanic and coral.

The relief of volcanic islands is mountainous, while that of coral islands is low-lying. On the vast mainland islands, mountains are combined with plains.

Mainland Islands were formerly parts of the mainland, and were separated from it due to the sinking of land areas below sea level. These islands are located on the shelf.

For example, several tens of thousands of years ago largest island Oceania – New Guinea– was connected to Australia by a 150-kilometer bridge. Its lowering is only

30 m led to the formation of the Torres Strait. The islands of New Zealand are also of continental origin (see Fig. 2).

Rice. 2. Mainland Island (New Zealand)

Volcanic Islands are the surface peaks of the largest underwater volcanoes, the foot of which lies on great depths(up to 5 km) (see Fig. 3).

These islands are small, rocky, topped with cones of extinct or active volcanoes. They are located mainly in groups. For example, the Hawaiian Islands are 24 islands and stretch over 2,500 km. They are formed by powerful outpourings of lava from underwater and terrestrial eruptions volcanoes millions of years ago. The largest of the islands, Hawaii, is formed by extinct and active volcanoes. Among them is the highest peak in Polynesia - the Mauna Kea volcano (4,210 m).

Rice. 3. Volcanic Island

Coral Islands formed by marine organisms - coral polyps living inside limestone skeletons (see Fig. 4). Clusters of coral skeletons form reefs– elongated strips – or atolls– small ring-shaped islands.

Rice. 4. Coral Island

The foundation for corals is usually the top of an underwater volcano. Therefore, many volcanic islands are surrounded by coral reefs. All coral structures rise above the water only a few meters. That's why the coral islands are low. They rarely rise above 5 m above ocean level and are barely noticeable among the expanses of water. That is why legends say that the inhabitants of Oceania “fished out” their islands from the ocean floor.

Climate

The climate is warm and mild, since most of the islands lie in equatorial and tropical latitudes; only New Zealand enters the temperate latitudes.

Air temperatures are high, but the heat is softened by moist winds from the ocean. They cause heavy rains, so the amount of precipitation is large - more than 4,000 mm per year.

On windward slopes high volcanoes Hawaiian Islands is the wettest place on Earth: 12,500 mm of precipitation falls there per year. But on the leeward slopes there is very little precipitation (200 mm). Tropical cyclones arise in Oceania, which are called typhoons in the Northern Hemisphere, and hurricanes in the Southern Hemisphere. Most of them occur in the southwestern part of the Pacific Ocean. They lead to great destruction. However, in general, despite these dangerous natural phenomena, it is never cold or hot on the islands. Therefore, the climate of Oceania is considered the most comfortable on Earth.

Organic world

The isolation of the islands is the reason for the uniqueness of their organic world. Life is poorest on small and relatively young coral islands; on mainland islands it is richer and more diverse.

Due to the difference in moisture (either a lot or little precipitation), both evergreen moist forests and dry savannas are common.

Coconut and sago palms, melon and breadfruit trees, ficus trees, and orchids grow in the forests. Among the wild plants there are many useful ones - trees with valuable wood (ironwood and sandalwood), plants with juicy fruits (papaya, mango, bananas); plants that produce spices (ginger, nutmeg, pepper). However, the first place undoubtedly belongs to the coconut palm (see Fig. 5).

Rice. 5. Coconut tree

Coral islands with poor soils, lying in a thin layer on coral limestones, have poor herbaceous vegetation. Their only decoration is groves of coconut palms. Interestingly, volcanic and coral islands were populated by plants with the help of wind, currents and even birds that carried their pollen, seeds, and nuts.

Oceania has many endemics - species of plants and animals that are found nowhere else. For example, tree ferns and cabbage trees grow only in New Zealand. Nowadays, natural forests on the islands are almost eliminated. In their place were plantations of agricultural crops.

Animal world the islands are poor. Among terrestrial animals there are almost no mammals (except mice and rats).

But there are a lot of birds of paradise, pigeons, parrots, weed chickens. The lack of predators led to the appearance of birds without wings - kaguya and kiwi. There are no poisonous snakes on the islands. There are reptiles - geckos, iguanas, lizards, hatteria. The waters surrounding the reefs and islands are home to flying fish, sharks, sea ​​turtles and snakes. Humans played a major role in the spread of animals. The dogs, cats, and pigs he brought multiplied greatly and subsequently went wild.

The giant Moa bird that no longer exists

Before the arrival of man, New Zealand was a kingdom of birds. Mammals, with the exception of a few species of bats, did not exist here. The queen of this feathered state was the giant moa bird...

Its largest specimens reached two meters at the shoulder and weighed more than 200 kg. Females were almost twice as heavy as males.

The giant moa had a natural enemy - the giant eagle, the largest bird of prey on the planet (see Fig. 6).

Rice. 6. Image of the Moa bird

Bibliography

MainI

1. Geography. Land and people. 7th grade: Textbook for general education. uch. / A.P. Kuznetsov, L.E. Savelyeva, V.P. Dronov, series “Spheres”. – M.: Education, 2011.

2. Geography. Land and people. 7th grade: atlas. Series "Spheres".

Additional

1. N.A. Maksimov. Behind the pages of a geography textbook. – M.: Enlightenment.

1. Russian Geographical Society ().

3. Textbook on geography ().

4. Gazetteer ().

Geography of Australia and Oceania
Click to enlarge

Oceania is divided into several large regions: Australia, Melanesia, Micronesia, and Polynesia.

In addition, Oceania includes thousands and thousands of coral islands located along the coasts of countries in the region. Some definitions include all states and territories in the Pacific Ocean between the North and South America and Asia, in which case Taiwan and Japan would also be part of Oceania, not Asia.

Oceania is not only a geographical region and ecozone, it is also a geopolitical region defined by the United Nations, and includes Australia, New Zealand, Papua New Guinea, and others island states, which are not included in the Asian region, as well as a mass of coral atolls and volcanic islets of the South Pacific, including Melanesian and Polynesian groups. Oceania also includes Micronesia, a widely scattered group of islands stretching along the northern and southern edges of the equator.

Oceania, the planet's smallest continent, is without a doubt one of the most diverse and amazing regions on the planet.

Islands of Oceania

Geographical diversity of Oceania

Oceania is represented by a variety of landforms, the most significant of which are located in Australia, New Zealand, and Papua New Guinea. And, since most of the islands of Oceania are represented only simple dots on the map, it is impossible to display their relief and landscape features.

Many of these small islands are the result of ancient volcanic activity, or are coral atolls surrounding part or all of the lagoon. Only a few islands have rivers of any significant size, and the same applies to lakes. Therefore, only recognized ones will be listed below. geographical features and attractions of Australia.

Relief and landscape of Australia

Australia is very dry, with only 35 percent of the country receiving little (sometimes no) rainfall. Almost 20 percent of the country is desert in one form or another.

Lake Eyre Basin

Lake Eyre itself is 16 m below sea level, and is located in the driest part of Australia. It usually contains some water, but recently, due to the harsh dry conditions in the country, it has no water at all. The Lake Eyre basin is considered the world's largest inland drainage system, covering an area of ​​one-sixth the total area countries. Rivers in this region flow depending on rainfall, and because there is very little rainfall, isolated water wells are essential to life.

Great Sandy Desert

This arid Western Australian steppe, south of the Kimberley Plateau, covers an area of ​​almost 300,000 sq km and contains scattered bush vegetation and rocks. It has miles of red sand ridges (dunes) and very few people live on it.

Great Victoria Desert

Known for its red sand dunes, native wildlife and isolation, the Victoria Desert (nearly 350,000 sq km in area) is almost 750 km wide and is a mostly barren area of ​​red sand hills and ridges. , dry salt lakes, with very little big amount greenery

Great Artesian Pool

It is one of the largest artesian groundwater basins in the world and is also a vital source of water for Australian agriculture.

Big barrier reef

This picturesque coral reef, approximately 2,000 km long, contains the largest coral deposits in the world. It is not a single reef, but rather an unusual mosaic of over 2,800 independent coral reefs. Known around the world for its beauty and wildlife (there are over 1,500 species of fish alone), it was Australia's first World Heritage in 1981

Great Dividing Range

Situated along the eastern/south-eastern edge of the country, and extending all the way to Tasmania, these mountain ranges and ridges separate Australia's dry interior from its coastal regions. The highest point is Mount Kosciuszko (2,228 m) in the Australian Alps. The Blue Mountains National Park, a World Heritage Site in New South Wales, two hours' drive from Sydney, is one of the world's most... beautiful places in the world, and one of Australia's most visited places.

Shark Bay

Shark Bay is one of only 14 places on the planet that meet all four natural criteria to be designated a World Heritage Site. These criteria include outstanding examples of earth evolution, biological and ecological processes, outstanding natural beauty, and significant natural habitats for animals and plants. This bay has the largest number of seagrass species for one location, and supports rich aquatic life for dolphins, dugongs, sea snakes, turtles, whales, and of course, sharks.

Fraser Island

Situated along the Australian Coral Sea, north of Brisbane, Fraser Island is Australia's fourth largest island (after Tasmania, Melville, and Kangaroo), and second largest sand island in the world. Created thanks to the efforts of winds over thousands of years, this island is 120 km long and 15 km wide.

Cape York Peninsula

Considered one of the "last remaining undeveloped areas on Earth", Cape York contains a large number of jagged mountains, tropical forests, vast mangrove forests, grasslands, swamps, and fast-flowing rivers.

Kimberley Plateau

The Kimberley, much of which is still unexplored, is famous for its dramatic red landscapes of cliffs and gorges, and for the very strong ocean tide that occurs twice daily, which accelerates river flows to dangerous levels and creates whirlpools. Dozens of islands and coral reefs line the coastline, and access to this region of Australia is very difficult, as there are few roads leading here.

Gibson Desert

Covered with small sand dunes and several rocky hills, this 156,000 sq. km. The desert is home to many Aboriginal reserves. Lack of rain makes farming and raising livestock difficult here.

Simpson Desert

This desert, measuring 176,500 square kilometers, is drifting. Its windswept dunes are starved of rain and the summer heat can be brutal. High temperatures in the desert often exceed 50ºC, and although people are advised to exercise extreme caution in this region, summer time years, the desert itself is definitely not lifeless. Tourists often visit here during winter and they often visit the spectacular scenery national park Queensland Simpson Desert.

Tanami Desert

Similar to the Great Sandy Desert, this desert also has many red sand plains, is also dominated by shrub vegetation, and has lonely hills scattered throughout its territory. The desert is generally uninhabited, except for a few mines and a small livestock farm.

Nullarbor Plain

This sparsely populated area of ​​southwestern Australia is very dry and has very little water. It can only be reached by crossing the Eyre Highway, named after the famous explorer Edward John Eyre, who became the first person to cross Australia from east to west in the mid-1800s. Along south coast The local topography of the Great Australian Bight has no equal. Huge stretches of pure white sand, which can be found at the Baxter Rocks along the Bay, are very impressive.

Darling/Murray river system

The Darling River, 1,879 km long, flows southwest from the banks of the Great Dividing Range to the Murray River. The Murray originates in the Australian Alps and flows for 1,930 km. to Spencer Gulf, immediately west of Adelaide. This longest river in Australia, and it is a vital source of irrigation for the country's largest agricultural region.

Darling Range

This one is low Mountain chain passes off the southwestern coast of Australia. Its highest point is Mount Cook (580 m).

MacDonnell Range

Famed for Ayers Rock, and as a favorite destination for hikers and rock climbers, this range of hills, ridges, and valleys is very popular due to its consistently good weather and beautiful landscape. The highest point is Mount Zil (height - 1,531 m).

Hamersley Ridge

A reddish-brown low mountain range located in Western Australia, home to many Aboriginal people. This national park famous for its red rock gorges and waterfalls.

Ayers Rock (Uluru)

- a geographical, often geopolitical region of the world, consisting primarily of hundreds small islands and atolls in the central and western Pacific.

Total area of ​​the islands- 1.26 million km² (together with Australia 8.52 million km²)
Population- 10.7 million people. (together with Australia 32.6 million people)
Divided into Melanesia, Micronesia and Polynesia; New Zealand is sometimes singled out.
The islands of Oceania are washed by numerous Pacific seas (Coral Sea, Tasman Sea, Fiji Sea, Koro Sea, Solomon Sea, New Guinea Sea, Philippine Sea) and Indian Oceans(Arafura Sea).

Geology

From a geological point of view, Oceania is not a continent: only Australia, New Caledonia, New Zealand, New Guinea and Tasmania are of continental origin, formed on the site of the hypothetical continent of Gondwana. In the past, these islands were a single landmass, but as a result of rising sea levels, a significant part of the surface was under water. The relief of these islands is mountainous and highly dissected. For example, highest mountains Oceania, including Mount Jaya (5029 m. highest high point oceania) , located on the island of New Guinea.

Most of the islands of Oceania are of volcanic origin: some of them are the summits of large underwater volcanoes, some of which still exhibit high volcanic activity(eg Hawaiian Islands).

Climate

Oceania is located within a few climatic zones: equatorial, subequatorial, tropical, subtropical, temperate. Most of the islands have a tropical climate. Subequatorial climate prevails on the islands near Australia and Asia, equatorial climate - west of the 180th meridian, tropical climate - north and south of the tropics, temperate climate - on most of the South Island in New Zealand.

The climate of the islands of Oceania is determined mainly by trade winds, so most of them receive heavy rainfall.
On the climate of the islands of Oceania big influence Anomalies such as the El Niño and La Niña currents also have an effect. During El Niño, the intertropical convergence zone moves north toward the equator; during La Niña, it moves south away from the equator. In the latter case, the islands experience severe drought, while in the former, heavy rains.

Most of the islands of Oceania are subject to the destructive effects of natural disasters: volcanic eruptions(Hawaiian Islands, New Hebrides), earthquakes, tsunamis, cyclones accompanied by typhoons and heavy rains, droughts. Many of them lead to significant material and human losses. For example, the tsunami in Papua New Guinea in July 1999 killed 2,200 people.

On South Island In New Zealand and on the island of New Guinea, there are glaciers high in the mountains, but due to the process of global warming, their area is gradually decreasing.

Soils and hydrology

Due to various climatic conditions Oceania's soils are very diverse. The soils of the atolls are highly alkaline, of coral origin, and very poor. They are usually porous, which is why they retain moisture very poorly, and also contain very little organic and mineral substances with the exception of calcium, sodium and magnesium. The soils of volcanic islands are usually of volcanic origin and are characterized by high fertility. On large mountainous islands there are red-yellow, mountain lateritic, mountain-meadow, yellow-brown soils, yellow soils, and red soils.

Large rivers are found only on the South and North Islands of New Zealand, as well as on the island of New Guinea, which is home to the largest rivers in Oceania, the Sepik (1126 km) and Fly (1050 km).

The largest river in New Zealand is the Waikato (425 km).

Flora and fauna

Kiwi is the symbol of New Zealand.

Oceania is included in the Paleotropical region of vegetation, with three subregions distinguished: Malesian, Hawaiian and New Zealand. Among the most widespread plants of Oceania are the coconut palm and breadfruit who play an important role in life local residents: the fruits are used for food, the wood is a source of heat, a building material, and copra is produced from the oily endosperm of coconut palm nuts, which forms the basis of exports for the countries of this region. A large number of epiphytes (ferns, orchids) also grow on the islands.

The fauna of Oceania belongs to the Polynesian faunal region with a subregion of the Hawaiian Islands. The fauna of New Zealand is allocated to an independent region, New Guinea - to the Papuan subregion of the Australian region. New Zealand and New Guinea are the most diverse. On the small islands of Oceania, primarily atolls, mammals are almost never found: many of them are inhabited only by the Polynesian rat. But the local avifauna is very rich. Most atolls have bird colonies where seabirds nest. Of the fauna of New Zealand, the most famous are the kiwi birds, which have become national symbol countries. Other endemic species of the country are kea, kakapo, and takahe. All the islands of Oceania are home to a large number of lizards, snakes and insects.

Minerals

Most of the islands of Oceania have no mineral resources, only the largest of them are being developed: nickel (New Caledonia), oil and gas (New Guinea island, New Zealand), copper (Bougainville island in Papua New Guinea), gold (New Guinea , Fiji), phosphates (on most islands the deposits are almost or already developed, for example, in Nauru, on the islands of Banaba, Makatea). In the past, many islands in the region were heavily mined for guano, the decomposed droppings of seabirds, which were used as nitrogen and phosphorus fertilizer. On the ocean floor of the exclusive economic zone of a number of countries there are large accumulations of iron-manganese nodules, as well as cobalt, but at the moment no development is being carried out due to economic inexpediency.

Groups of islands and archipelagos of the western and central parts are united in geographical area under the general name Oceania. Historically, all the islands have been divided into four ethnographic-geographical regions: (Tonga, Samoa, Cook, Hawaiian Islands, Easter Island, etc.), Melanesia (Island, Bismarck Archipelago, Islands, etc.), ( , Mariana Islands, etc.), New. Most of the islands of Oceania are concentrated between 10° S. w. and 20° N. w.

The Russian scientist N. N. Miklouho-Maclay made a great contribution to the study of the nature and population of Oceania. He studied the life of the peoples of the island of New Guinea and left descriptions of the nature of coastal areas. The scientific research of N. N. Miklouho-Maclay was associated with his conviction of the need to protect backward and oppressed peoples. In the very late XIX V. Our fellow countryman, a native of the Mogilev province N.K. Sudzilovsky, lived and worked in the Hawaiian Islands.

Geological structure and relief of Oceania

Remember how continental, volcanic and coral islands were formed. The largest mainland islands of Oceania are New Guinea and New Zealand. Volcanism is a characteristic process of this region. The Hawaiian Islands are home to Kilauea Volcano, one of the most active active volcanoes on Earth. Volcanic islands form giant island arcs. They have an elongated configuration. Oceania is replete with coral islands - reefs and atolls, which form entire archipelagos (Gilbert Islands, Tuamotu).

Oceania Climate

The islands of Oceania are located mainly in the equatorial, subequatorial and. Only Northern part The Hawaiian archipelago enters the subtropics, and South part New Zealand is located in the temperate zone. There are two climatic regions in Oceania: trade wind and monsoon. The climate of Oceania is characterized by slight temperature fluctuations: from +30 °C during the day to +21 °C at night. Winds from the ocean soften the heat. It is never too cold or too hot here, so the climate of Oceania is considered the most comfortable in the world. globe. The main directions are from east to west. They facilitate the dispersal of organisms.

Marine air masses dominate in Oceania. In areas where monsoon circulation predominates, precipitation falls 3000-4000 mm per year. In the Hawaiian Islands, on the windward slopes, over 12,090 mm of precipitation falls per year. This is one of the wettest places on Earth. The distribution of precipitation is related to the presence of mountains. There are areas on the island of Hawaii that receive less than 200 mm of precipitation per year.

Among the very dangerous and destructive natural phenomena Tropical hurricanes are not observed. They destroy plantations, destroy homes, and sometimes the resulting waves wash away all living things. The local population is wary of settling on the Cook Islands and Tuamotu, where hurricanes are frequent. A subtropical and temperate climate is characteristic of New Zealand, where in winter there are frosts down to -13 ° C, and there is snow in the mountains.

Flora and fauna of Oceania

The isolation of the island land had the greatest impact on its and. The diversity of the plant and animal world depends on the age of the islands, their size and distance from the mainland. It is poorest on coral islands, where fresh water is scarce and soils are poor. Only a few dozen species of plants grow on them. On the islands of Oceania, mainly in Melanesia, the most ancient plants have been preserved, for example tree ferns, reaching 8-15 m in height. Rich and original vegetable world New Zealand (pines, palms).

Vegetable and animal world Oceania is distinguished by two features. Rare species that are not found on the mainland have been preserved here. At the same time, on many islands, entire groups of organisms common to the mainland are almost completely absent. Many species of flowering plants found on land are absent here, but spore-bearing plants are widespread. Ancient plants that grew on the mainland in the geological past (podocarpus, agathis (kauri), etc.) have been preserved on the islands.

The fauna of the islands is poor. There are no mammals on many islands, with the exception of rats, mice, goats and cats that were introduced here. There are many seabirds: petrels, albatrosses, gulls that nest and raise their chicks here. On the island of New Guinea there is a weed chicken, a representative of the Australian fauna.

In New Zealand, the oldest flightless bird, the kiwi, is preserved, a very cautious bird that lives in dense grasses, the Maori rail. The kiwi bird is featured on the coat of arms of New Zealand. Rare species of parrots are found in New Zealand and New Zealand - the kakapo, or owl parrot, and the kea parrot, with a strong, sharp and curved beak. The first lizard tuateria was preserved on one of the islands of New Zealand.

On individual islands Only 5-7 species of seabirds nest. At the same time, the number of bird species in New Guinea is more than 100, and the insect fauna is rich (more than 3,700 species).

Minerals of Oceania

Minerals on the islands of Oceania are distributed extremely unevenly. Farming is carried out where there are valuable minerals. Thus, New Caledonia contains up to 25% of the world's nickel reserves, and Christmas Island has phosphate reserves. Among the states of Oceania, Papua New Guinea stands out, where there is gold, silver, and reserves have been explored.

Economic activities of Oceania

The population of Oceania is about 10 million people. There are several hypotheses about the routes of settlement of Oceania. Most scientists believe that Oceania was settled by people from South-East Asia many thousands of years ago. According to Thor Heyerdahl's hypothesis, immigrants from America settled there.

The inhabitants of Oceania were skilled sailors and shipbuilders. They sailed thousands of kilometers from their home islands. Modern residents of Oceania are engaged in growing coconut trees, bananas, cocoa, and coffee. Traditional trade is fishing. The nature and life of the people of Oceania are largely subject to natural catastrophic disasters (tropical hurricanes, tsunamis, earthquakes, volcanism).

On many islands of volcanic and continental origin, non-ferrous metal ores, coal are mined, and phosphorite deposits are developed. Every year, the states of Oceania become targets international tourism. The nature of the islands is changing under the influence economic activity person. In place of the destroyed natural plantations, plantations have been created where sugar cane, pineapples, bananas, tea, coffee, rubber and other crops are cultivated.

Oceania political map

Modern political map Oceania emerged as a result of a long struggle between the colonial powers to divide the oceanic archipelagos among themselves. Until the beginning of the 60s. XX century There was one independent state in Oceania - New Zealand. By the end of the twentieth century. More than 10 independent states were formed in Oceania. A number of islands and archipelagos remain politically and economically dependent on the world. Most of the Hawaiian Islands archipelago has formed the 50th state of the United States since 1959.

The formation of the nature of Oceania is influenced by Pacific Ocean, its distance from other continents, location in tropical latitudes. The basis of the economy of most countries in Oceania is agriculture. Mining is carried out on many islands.

Phosphorite deposits have been mined. In the past, many islands in the region were heavily mined for guano, the decomposed droppings of seabirds, which were used as nitrogen and phosphorus fertilizer. On the ocean floor of the exclusive economic zone of a number of countries there are large accumulations of iron-manganese nodules, as well as cobalt, but at the moment no development is being carried out due to economic inexpediency.

5. Climate

Oceania is located within several climatic zones: equatorial, subequatorial, tropical, subtropical, temperate. Most of the islands have a tropical climate. A subequatorial climate prevails on the islands near Australia and Asia, as well as east of the 180th meridian in the equator zone, equatorial - west of the 180th meridian, subtropical - north and south of the tropics, temperate - on most of the South Island in New Zealand.

The climate of the islands of Oceania is determined mainly by trade winds, so most of them receive heavy rainfall. Average annual rainfall ranges from 1,500 to 4,000 mm, although some islands (particularly due to topography and downwind areas) may have drier or wetter climates. Oceania is home to one of the wettest places on the planet: on the eastern slope of Mount Waialeale on the island of Kauai, up to 11,430 mm of precipitation falls annually (the absolute maximum was reached in 1982: then 16,916 mm fell). Near the tropics average temperature is about 23 °C, at the equator - 27 °C, with a slight difference between the hottest and coldest months.

The climate of the Oceanian islands is also greatly influenced by such anomalies as the El Niño and La Niña currents. During El Niño, the intertropical convergence zone moves north toward the equator; during La Niña, it moves south away from the equator. In the latter case, the islands experience severe drought, while in the former, heavy rains occur.

Most of the islands of Oceania are subject to the destructive effects of natural disasters: volcanic eruptions (Hawaiian Islands, New Hebrides), earthquakes, tsunamis, cyclones accompanied by typhoons and heavy rains, droughts. Many of them lead to significant material and human losses. For example, the tsunami in Papua New Guinea in July 1999 killed 2,200 people.

There are glaciers high in the mountains on the South Island of New Zealand and on the island of New Guinea, but due to global warming, their area is gradually decreasing.

6. Soils and hydrology

Soils are very diverse due to different soil formation conditions. On the large mountainous islands of western Oceania, in a hot and humid climate, red-yellow lateritic soils are developed under moist evergreen forests; higher up the slopes there are mountain lateritic soils, yellow soils, red soils and yellow-brown soils; at the most high peaks- mountain meadows. In central and eastern Oceania, lateritic soils are found only in large islands composed of weathered lavas. On fresh ashes and young lavas there are Andosols, dark-colored and fertile. Deforestation, plowing and natural disasters cause severe erosion. The soils of the atolls are thin, carbonate, and often saline.

Rivers and lakes are found mainly on large mountainous islands in the western part of Oceania, composed of sedimentary and crystalline rocks. There are few or no rivers or lakes on the volcanic and coral islands and eastern Oceania, where atmospheric moisture seeps into porous basalts and limestones. The rivers are fed mainly by rain, only some mountain rivers New Guinea and New Zealand have additional snow and glacial feeding. The maximum flow occurs at the end of summer (with glacial feeding during the summer). Maximum winter flow - at short rivers New Zealand (South Island). Almost all large rivers begin high in the mountains, where they flow in deep valleys, have rapids beds, and have large reserves of hydropower. On coastal lowlands they sharply slow down the flow, are navigable, and have swampy valleys. The mouths of small rivers are blocked by sand spits and mangroves. Largest rivers Oceania - Fly and Digul in New Guinea.

On coral and small volcanic islands there are lenses of fresh water that lie above salt water in the soils near the coast. Most large lakes Oceania is volcanic or glacial, smaller ones are oxbow lakes in wide valleys in the lowlands. In areas of active volcanism there are many thermal and salt lakes. New Zealand has the most lakes (there are many geysers on the North Island).

The largest number of lakes, including thermal ones, are located in New Zealand, where there are also geysers. On other islands of Oceania, lakes are a rarity.

7. Flora and fauna

The position in a vast expanse of water, the small size of the land and the distance from the continents and each other had a significant impact on the nature of the islands and the life of the peoples of Oceania.

Oceania is included in the Paleotropical region of vegetation. There are 3 subregions: Malesian, Hawaiian, New Zealand. Malesian is characterized by numerous tropical families (pandanus, palms, ficus, laurel, water lilies, bananas, as well as widespread legumes). There are a lot of epiphytes (ferns, orchids). In Hawaiian there are no gymnosperms, ficus trees, there is only one genus of palms (Pritchardia), few orchids, but many ferns - the first plants to settle in the cracks of cooled lava flows. In the New Zealand subregion there are numerous species of Asteraceae, ferns, sedges, and grasses.

Among the most widespread plants in Oceania are the coconut palm and the breadfruit tree, which play an important role in the lives of local residents: the fruits are used for food, the wood is a source of heat, a building material, and copra is produced from the oily endosperm of coconut palm nuts, which forms the basis of exports to the countries of this region. A large number of epiphytes (ferns, orchids) also grow on the islands. Largest number endemics (both flora and fauna) have been recorded in New Zealand and the Hawaiian Islands, with a decrease in the number of species, genera and families of plants from west to east.

On high mountainous islands, on wet windward slopes up to an altitude of 300-600 m, xerophilous hard-leaved forests, thickets of shrubs, and savannas are common; up to 1000-1800 m in a more humid but still hot climate - moist evergreen forests. Up to 3000 m in a cool and very humid climate - “fog belt forests” with shorter trees, an abundance of mosses, lichens, and ferns. The tops of the highest islands have alpine vegetation (cushion grasses, low-growing shrubs and shrubs). On the leeward, drier slopes below there are deserted savannas and semi-deserts with xerophilic prickly, often cushion-shaped grasses, small-leaved shrubs, and low trees; higher up are xerophilic hard-leaved forests, shrubs, and savannas. With an altitude of about 1500 m, a narrow belt of evergreen forests appears. On coral islands the vegetation is especially poor in species.

Large areas are occupied by plantation crops and pastures (New Zealand); The forest area has greatly decreased. Introduced animals caused great damage to vegetation.

The fauna of Oceania belongs to the Polynesian faunal region with a subregion of the Hawaiian Islands. The fauna of New Zealand is allocated to an independent region, New Guinea - to the Papuan subregion of the Australian region. New Zealand and New Guinea are the most diverse. On the small islands of Oceania, primarily atolls, mammals are almost never found: many of them are inhabited only by the Polynesian rat. But the local avifauna is very rich. Most atolls have bird colonies where seabirds nest. Of the fauna of New Zealand, the most famous are the kiwi birds, which have become the national symbol of the country. Other endemics of the country are kea (Latin: Nestor notabilis, or nestor), kakapo (Latin: Strigops habroptilus, or owl parrot), takahe (Latin: Notoronis hochstelteri, or wingless plume). All the islands of Oceania are home to a large number of lizards, snakes and insects.

During European colonization alien species of plants and animals were introduced to many of the islands, which negatively affected the local flora and fauna.

The region contains a large number of protected areas, many of which occupy large areas. For example, the Phoenix Islands in the Republic of Kiribati have been the world's largest marine reserve since January 28, 2008 (area 410,500 km²).

Over time, the fauna and animal population of the islands change significantly. The study of the dynamics of island faunas is of great practical interest. The replenishment of island biota depends, as already noted, on the area of ​​the island and the distance from it to the mainland or other source of settlement.

How larger area island, the more species live on it. This is because larger islands have more diverse habitats suitable for colonization by different species.

The peculiarity of island faunas is that they are often the last refuges of archaic animal species.

8. Man in Oceania

Man appeared in Oceania many thousands of years ago. It is not yet clear how the islands were populated. The population is 10 million people. The indigenous people of New Guinea belong to the equatorial race (Papuans). Indigenous people other islands belongs to a special Polynesian group. In New Zealand, the majority of the population are descendants of immigrants from Europe.

 

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