Vegetation zones

Areas near the equator receive a lot of solar radiation. Tropical rainforests depend on this solar radiation, as it guarantees warm temperatures throughout the year. As the name of the vegetation zone suggests, tropical rainforests also experience a large amount of rainfall throughout the year.

The vegetation of a tropical rainforest rises in thick layers. The trees often grow tens of metres tall as they compete for sunlight. The plant life of the tropical rainforests is extraordinarily diverse. Over 50 percent of the world's known species of flora and fauna live in the tropical rainforests.

New, previously unknown species of organisms are found every year in tropical rainforests. Likewise, species that were unknown to science also become extinct every year.

The best-known desert on Earth is probably the Sahara Desert in North Africa. Deserts are found in many different continents, and they cover almost 20 percent of the planet's land surface area.

Deserts receive only a little rainfall, but they are not completely waterless. Water can be found in deserts in the form of oases, which have formed near underground water concentrations.

Desert plants have developed different strategies for conserving and storing water. For example, species of cacti store water by using their stems, leaves and roots. It is also possible for plants to slow down the rate at which water evaporates from their stems with the help of specialised structures, such as hairy stems that gather moisture.

The living conditions of desert ecosystems are also difficult for animals. The most common desert-dwelling animals are reptiles and rodents. As the days are extremely hot, many desert animals only become active during the night. During sandstorms, the animals take shelter in caves and holes in the ground.

As its name suggests, Mediterranean vegetation is mostly found in Mediterranean Europe. Similar vegetation is also found in some parts of the Americas, such as California and Chile, where the vegetation type is called chaparral.

In many areas, especially in Europe, the original Mediterranean vegetation has vanished as the result of human habitation and agriculture.

The vegetation zone is characterised by a long and hot summer that is balanced by a short, temperate winter.

The plants of the Mediterranean vegetation zone have adapted to these climatic conditions with small, wax-covered leaves. These kinds of leaves prevent water from evaporating during the hot summer. Dry areas are dominated by shrubs, whereas regions that receive more rainfall are characterised by forests.

Broadleaf forests were previously the most common vegetation type in Europe. Nowadays, only a small fraction of these forests remain. Broadleaf forests have been cut down by humans, because their nutrient-rich soil and climatic conditions are well suited for agriculture.

The broadleaf forest zone is suitable for agriculture because it receives the perfect amount of rainfall and solar radiation for crop growth. Many countries with productive agricultural sectors, such as France and Germany, are found in the broadleaf forest zone.

As their name suggests, broadleaf forests are characterised by the presence of broadleaf trees, such as oak, maple and beech.

Broadleaf forests are full of animal life: they are home to squirrels, hedgehogs, mice, boars and deer. Many frog and reptile species also thrive in broadleaf forests.

The Northern coniferous forest zone circles the planet's northern hemisphere, covering most of Russia, Northern Europe, and North America. Approximately 15 percent of the planet's land surface area is covered by coniferous forest. Northern coniferous forest is also known as boreal forest or taiga.

The plants of the coniferous zone – coniferous trees, mosses, lichens, blueberries and lingonberries – form large populations in the forests of the northern hemisphere. They have adapted to cold and dark winters.

Spruce and pine are the two most common tree species of boreal forests. These coniferous trees dominate the landscape of the taiga, and provide resources for the large lumber and paper industries found in nations located in the coniferous forest zone.

Northern coniferous forests receive large amounts of rainfall. However, as the temperatures remain quite low throughout the year, only a relatively small fraction of this water evaporates. This has resulted in the formation of lakes and bogs.

The vegetation of the northern frigid zone must endure harsh climatic conditions. Only a few plant species are up to the task. In the northern frigid zone, the vegetation consists of low shrubs, grasses, mosses and lichens.

Tundras are almost completely free of trees. Tundra is found in the northernmost areas of Europe, such as Iceland, Norway and Russia.

During the summer, large insect populations lure migrating birds to tundra regions. Other animals of the tundra include small mammals, such as voles, as well as larger mammals, such as polar bears.

The soil type of the temperate grassland zone is rich in nutrients. Despite this, no trees grow in these areas. This is the case because there is not enough rainfall or moisture to maintain tree growth.

The vegetation of the temperate grassland consists of various kinds of different grasses and bulbous plants. These plants thrive in the dry conditions of the steppes.

Small rodents are the most common animals of the temperate grasslands. The large grasslands of North America, the prairies, are also home to larger mammals such as buffaloes.

The mountain ranges of planet Earth are characterised by a special type of vegetation. When climbing a mountain, the air gradually becomes colder the higher the elevation becomes. This results in a large amount of variation in vegetation at different elevations.

In the temperate zone, the vegetation of mountain ranges consists of broadleaf and coniferous forests. Conifers such as spruce and pine thrive at higher elevations than broadleaf trees.

Mountain vegetation refers to the scarce vegetation type found at high-elevation areas. This kind of vegetation, which is similar to that found in northern tundras, can be found in tall mountain ranges such as the American Cordillera and the Alps of Central Europe.

In mountainous regions, the temperature variation between day and night is often drastic. The afternoons can be hot, whereas the nights can receive sub-zero temperatures. Different species of low shrubs and grasses have adapted to these conditions.