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UNIT 7: WORLD LANDSCAPES

1.      NATURAL LANDSCAPES

Natural landscapes are found around the world, sharing conditions such as climate, vegetation, soil and fauna. These large regional habitats are called biomes. We can classify the world’s biomes in different groups, according to their latitude. They include the following:
- Cold climates: the tundra and the perpetual ice of polar regions.
-Temperate climates: oceanic, continental and Mediterranean landscapes.
-Hot climates: equatorial and tropical rainforests, the savannah and hot deserts.
-Other landscapes: mountain areas and humid areas, like mangroves and dunes.

2.      NATURAL LANDSCAPES IN COLD CLIMATES

Two types of climate are found near the polar circles: the Arctic tundra and the perpetual ice of the polar regions.

THE TUNDRA

The tundra is a vast area of low land near the Arctic Ocean in the Northern Hemisphere. Moss, lichen and small shrubs grow in the topsoil. However, the frozen subsoil, or permafrost, does not allow trees to grow there. Migrating birds eat insects in lakes and marshes during the summer. Other animals include reindeer, moose, Arctic foxes and Arctic hares.

THE TUNDRA IN DANGER

The tundra is threatened by global warming. As temperatures rise, permafrost melts under the ground. The softened earth then releases methane gas from frozen deposits deep underground. This gas is one of the causes of the greenhouse effect.

PERPETUAL ICE
Perpetual ice is found in polar regions. The ground is frozen all the year round so there is no vegetation. Only a few species of animals, like seals and polar bears, can adapt to the cold and lack of vegetation typical of these regions.

3.      THE NATURAL LANDSCAPES IN TEMPERATE CLIMATES

The natural landscapes of continental, oceanic and Mediterranean climates are found in the températe latitudes, between the tropics and the polar circles.

CONIFEROUS FOREST

Coniferous forests, also known as the taiga, are found in continental climates, south of the Arctic tundra. These forests stretch across the north of Europe, Asia and North America. Conifers, such as pine and fir trees, can survive very cold winters when the ground freezes. The fauna includes deer, bears and lynxes.

THE TAIGA IN DANGER

The taiga is threatened by global warming that dries the soil, and increases the risk of forest fires. The taiga is also threatened by deforestation because millions of trees are cut down each year to make products like paper.

GRASSLAND AND STEPPE

Grasslands and steppes are usually found in continental climates, south of the taiga, where temperatures are higher. The soil is generally fertile in grasslands. Animals include foxes and moles.

DECIDUOUS FOREST

Deciduous forests are found in oceanic climates, where temperatures are mild and rainfall is abundant. Deciduous trees, such as oak, beech and maple, lose their leaves in the autumn. These leaves enrich the soil making it very fertile. The varied fauna includes deer, rabbits and many species of birds. Bushes and low grass often grow in areas where the forests have disappeared. Deciduous forests are a threatened ecosystem. Human activity affects these forest due to the fertility of the soil that is then used for agriculture. Climate change is also a great threat to these forests.

MEDITERRANEAN FOREST AND SCRUBLAND

Mediterranean forests are found in Mediterranean climates. The trees in these forests are perennial, meaning they don’t lose their leaves. They include holm oaks, cork oaks and pine trees. The fauna includes deer, rabbits and birds of prey. We also find scrubland in areas where there are fewer trees. Plants like thyme and rosemary grow in scrubland. The soil is fertile near river beds, but less fertile where erosion has occurred.

4.      NATURAL LANDSCAPES IN HOT CLIMATES

The natural landscapes of hot climates are found between the Tropic of Cancer and the Tropic of Capricorn, where it is hot all the year round and there is no winter.

RAINFOREST

Rainforests are vital for our planet because their vegetation absorbs carbon dioxide, and they supply us with wood and other products.
-Equatorial rainforests are found near the Equator in South America, Africa, Asia and Oceania, where precipitation is abundant and temperatures are high. Vegetation is dense and varied, due to the heat and humidity. At the highest level, or canopy, the tallest trees receive the most sunlight. Moss and fungi grow on the forest floor, where the soil is poor. Plant species include rubber and banana trees and bamboo. The fauna is varied and abundant. It includes many species of insects and colourful birds, as well as apes, reptiles and amphibians.
-Tropical rainforests are found at higher latitudes, and are similar to equatorial rainforests. However, the trees are not as high and the vegetation is not as dense. Consequently, more light reaches the forest floor, where smaller trees, shrubs and ferns grow.

THE AMAZON IN DANGER

The Amazon rainforest is important for Earth’s biodiversity because it is home to numerous species of plants and animals. But every year, many trees are cut down and the land is used for agriculture. The region’s natural reserves are over-exploited, and it is polluted by the millions of people who live along the Amazon river.

THE SAVANNAH

Savannahs are found in tropical climates, usually between rainforests and hot deserts. The savannah has very tall grass during the rainy season. It also has shrubs and some scattered trees. The fauna is abundant and varied, including elephants, giraffes, lions and zebras.

THE SAVANNAH IN DANGER
The savannah is threatened by drought. Global warming and the lack of water cause soil erosion and desertification. Agriculture and stock farming also affect this ecosystem.

HOT DESERT

Hot deserts are found in tropical areas where rainfall is very scarce.There is very little vegetation because of the lack of water, and only a few plants, like cactuses, can grow. The water in oases allows palm trees and other plants to grow there. The fauna in deserts is also scarce with reptiles, rodents and some predators.

5.      MOUNTAIN LANDSCAPES

Not all landscapes are found in just one climate zone. They are influenced by other factors such as relief, soil and water. Mountain landscapes are determined by elevation. The higher a mountain, the colder and windier it is. Vegetation is denser at lower altitudes, and is also affected by the amount of sunlight the mountain receives. Some animals, such as mountain goats and birds of prey, are suited to a mountain environment. Vegetation zones are different in temperate climates and hot climates.

6.      COASTAL LANDSCAPES

Water has a key role in the formation of coastal landscapes. Here are three examples:

MANGROVES

Mangroves are coastal seawater habitats in the tropics. Their vegetation includes a variety of species of mangrove trees, which adapt to salt water. They are the habitat for a variety of fish, reptiles and birds. Many small animals, such as crabs, live in the trees’ twisted roots, which are exposed to the air at low tide.

WETLANDS

Wetlands are areas of land, such as marshes, that are partly covered by water. Wetlands may have saltwater, fresh water or a mixture if the land is close to a river estuary. Aquatic plants adapt to this type of environment. The fauna includes many species of insects, as well as birds that feed on the insects.
Unit 7: World landscapes
COASTAL DUNES

Coastal dunes form where sand accumulates in the sea and the wind blows it inland. Dunes are mounds of sand, caused by the wind. Only a few strong grasses can grow in dunes. The fauna is also scarce, and includes reptiles and rodents.

7.      HUMAN INFLUENCE ON LANDSCAPES

Our natural environment is vital to us in different ways. Most of the world’s population lives in regions where food is grown easily, and only a few people live in deserts or mountains. We need fresh water for human consumption and agriculture. It is important for our health to breathe unpolluted air. Humans change their environment all the time. They build roads and cities. Agriculture and mining also transform landscapes. But it is important that these changes do not cause long-term harm to the environment: we call this goal sustainable development.

ENVIRONMENTAL PROBLEMS

-Air pollution is caused by gases released by industry and traffic. This causes problems such as acid rain, depletion of the ozone layer, and the greenhouse effect.
-Climate change is also connected to air pollution. Global warming will cause glaciers and polar ice caps to melt and will raise the level of the oceans. Desertification will increase.
-Vegetation. We cut down millions of trees every year. This deforestation causes soil erosion and leads to a loss of biodiversity. It may also cause desertification.
-Water. The pollution of rivers and lakes that dry up affect agriculture and livestock.

8.      NATURAL HAZARDS

Some natural phenomena have a major impact on people and the environment:
-Earthquakes are the shaking of the Earth’s crust as a result of the movement of tectonic plates. Most earthquakes are just light tremors, but violent earthquakes cause great damage. Underwater earthquakes create tidal waves, called tsunamis, which may also cause disasters in coastal areas.
-Volcanic eruptions change relief, raising mountains and even islands. Violent eruptions can cause great damage.
-Hurricanes are very strong winds accompanied by torrential rain. In some parts of the world they are called cyclones or typhoons.
-Flooding may occur after torrential rain. Rivers and lakes overflow and flood the surrounding land.

-Droughts occur when there has been no rain for a long time. There may be a shortage of water for agriculture and human consumption.

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