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Major Biomes of the world

news-details Image Source Feb 15, 2021 21:22 IST , Updated: Sep 25, 2021 17:30 IST · 10 min read

A biome is a large community of vegetation and wildlife adapted to a specific climate they exist in. The seven major types of biomes are Tundra, Taiga, Temperate deciduous forest, Tropical rain forest, Savannah, Grassland and Desert.

A biome, the largest geographic biotic unit includes various communities and is named for the dominant type of vegetation, such as grassland or coniferous forest.

A biota is a term used for all the living things at a certain time at a certain place, examples of biota include Cambrian biota and Madagascan biota.

1) Tundra

Tundra, a major zone of treeless level or rolling ground found in cold regions, mostly north of the Arctic Circle (Arctic tundra) or above the timberline on high mountains (alpine tundra).

Tundra the coldest of all the biomesm is known for large stretches of bare ground and rock and for patchy mantles of low vegetation such as dwarf shrubs, sedges, flowers and grasses, mosses, and lichens.

The fauna in the arctic is also diverse: Arctic hares and squirrels, arctic foxes, wolves, polar bears, loons, sandpipers, snow birds, mosquitoes, flies, moths, grasshoppers, blackflies, arctic bumble bees, cod, flatfish, salmon, snowy owl etc. Reptiles and amphibians are almost absent.

The tundra soil (permafrost) is rich in nitrogen and phosphorus.

It is noted for its frost landscapes, extremely low temperatures, little precipitation, poor nutrients, low biotic diversity and short growing seasons.

The average winter temperature is -34? C, but the average summer temperature is 3-12? C which enables this biome to sustain life. Yearly precipitation, including melting snow, is 15 to 25 cm.

There are three regions associated with tundra: Arctic tundra, alpine tundra, and Antarctic tundra. Arctic tundra is located in the northern hemisphere, encircling the north pole and extending south to the coniferous forests of the taiga.

Animals and birds have additional insulation from fat, many animals hibernate during the winter because food is not abundant. Another alternative is to migrate south in the winter, like birds do.

2) Taiga

The taiga also called boreal forest are thick forests of the cold, subarctic region (just south of the arctic circle). The taiga lies between the tundra to the north and temperate forests to the south.

The fauna consists of birds, hawks, fur bearing carnivores, little mink, elks, puma, Siberian tiger,wolverine, wolves etc.

The taiga forest has been called the world's largest land biome. In North America, it covers most of inland Canada, Alaska, and parts of the northern contiguous United States.

In Eurasia, it covers most of Sweden, Finland, much of Russia from Karelia in the west to the Pacific Ocean (including much of Siberia), much of Norway and Estonia, some of the Scottish Highlands, some lowland/coastal areas of Iceland, and areas of northern Kazakhstan, northern Mongolia, and northern Japan (on the island of Hokkaidō).

The taiga is characterized predominantly by a limited number of coniferous forests ? pine (Pinus), spruce (Picea), larch (Larix), fir (Abies) - and to a lesser degree by some deciduous genera such as birch (Betula) and poplar (Populus).

Coniferous trees have needles instead of broad leaves, and their seeds grow inside protective, woody cones. Conifers never lose their needles, for this reason, conifers are also called "evergreens."

These trees reach the highest latitudes of any trees on Earth.

The soil beneath the taiga often contains permafrost, in other areas, a layer of bedrock lies just beneath the soil. Both permafrost and rock prevent water from draining from the top layers of soil.

After the tundra and permanent ice caps, taiga is the terrestrial biome with the lowest annual average temperatures, with mean annual temperature generally varying from −5 to 5 ?C. Areas of the taiga located in the centre of continents generally receive 30 to 50 cm of annual precipitation.


3) Temperate deciduous forest

The temperate Deciduous forest (broad-leaf forests), vegetation composed primarily of broad-leaved trees that shed all their leaves during one season.

Deciduous forest is found in three middle-latitude regions with a temperate climate characterised by a winter season and year-round precipitation: eastern North America, western Eurasia, and northeastern Asia.

It has four distinct seasons: winter, spring, summer and fall.

Deciduous forest also extends into more arid regions along stream banks and around bodies of water.

They are found in areas with warm moist summers and cool winters. The average yearly temperature is about 10?C, and these areas get about 75 to 150 cm of of year-round precipitation.

These are generally the most productive agricultural areas of the earth.

The flora includes trees like beech, oak, maple and cherry, most animals are the familiar vertebrates and invertebrates - Insects, spiders, slugs, frogs, turtles and salamanders are common.

4) Tropical rain forest

Tropical rainforests are characterized by a warm and wet climate with no substantial dry season - typically found within 10 degrees north and south of the equator.

It is an area of tall, mostly evergreen trees and a high amount of rainfall. More than half of the world's plant and animal species live in tropical rain forests and tropical rainforests produce 40% of Earth's oxygen.

Rainforests thrive on every continent except Antarctica. The largest rainforests on Earth surround the Amazon River in South America and the Congo River in Africa.

Most rainforests are structured in four layers: emergent, canopy, understory, and forest floor. The top layer of the rainforest is the emergent layer. Here, trees as tall as 60 meters dominate the skyline.

Beneath the emergent layer is the canopy, a deep layer of vegetation roughly 6 meters thick. The canopy blocks winds, rainfall, and sunlight, creating a humid, still, and dark environment below. e.g. philodendron, strychnos toxifera, rattan palms - thousands and thousands of insect species can also be found in the canopy.

The understory is an even darker, stiller, and more humid environment. Plants here, such as palms and philodendrons, are much shorter and have larger leaves than plants that dominate the canopy.

The forest floor is the darkest of all rainforest layers, making it extremely difficult for plants to grow. Leaves that fall to the forest floor decay quickly.

Rainforests support a very broad array of fauna, including mammals, reptiles, amphibians, birds and invertebrates - bats, monkeys, snakes, lizards, jaguars and frogs.

5) Savannah

A savannah is a mixed woodland-grassland ecosystem (coexistence of trees and grasses) characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses.

Savannas grows under hot, seasonally dry climatic and maintain an open canopy despite a high tree density.

Savannas are also characterised by seasonal water availability, with the majority of rainfall confined to one season; they are associated with several types of biomes, and are frequently in a transitional zone between forest and desert or grassland.

The largest areas of savanna are found in Africa, South America, Australia, India, the Myanmar (Burma)-Thailand region in Asia, and Madagascar.

The fauna include a great diversity of grazers and browsers such as antelopes, buffaloes, zebras, elephants and rhinoceros; the carnivores include lion, cheetah, hyena; and mongoose, and many rodents.

Plants of the savannas are highly specialized to grow in this environment of long periods of drought. They have long tap roots that can reach the deep water table, thick bark to resist annual fires, trunks that can store water, and leaves that drop of during the winter to conserve water.

The savanna is covered by grasses such as Rhodes grass, red oats grass, star grass, lemon grass, and some shrubs.There are various types of trees that will grow in particular areas of a savanna biome. They include pine trees, palm trees, and acacia trees.

6) Grassland

Grasslands and areas in which the vegetation is dominated by a nearly continuous cover of grasses. Grasslands are found where there is not enough regular rainfall to support the growth of a forest, but not so little that a desert forms.

There are two main kinds of grasslands: tropical and temperate. Examples of temperate grasslands include Eurasian steppes, North American prairies, and Argentine pampas. Tropical grasslands include the hot savannas of sub-Saharan Africa and northern Australia.

Tropical grasslands receive 50 to 150 cm of rain in an average year and in every season experience temperatures of about 15 to 35 ?C. Temperate grasslands are somewhat drier than tropical grasslands and also colder.

Grasslands support the greatest aggregations of large animals on earth, including jaguars, African wild dogs, zebras, plains bison, mountain plover, african elephant, sunda tiger, black rhino, white rhino, savanna elephant, greater one-horned rhino, indian elephant, lions, cheetahs and swift fox.

Some grass species in these habitats include red oat grass and Rhodes grass in tropical savannas, and purple needlegrass and galleta in temperate areas.

Grasslands Region Major Economic Activity
Steppe Europe and North Asia
Pustaz Hungary Rich black soil
Abundant wheat production
Sugar from Sugar beet
Countries like Hungary, Ukraine, Romania, etc.
Prairies USA Wheat Granaries
Extensive Ranching
Pampas Argentina Alfalfa: nutrient-rich grass.
Ranching, cattle rearing; Dairy products
Extensive wheat-producing region
Economy depends on wheat and beef export
Velds South Africa Maize farms
Sheep and Cattle rearing
Downs Australia Sheep and Cattle rearing
Merino sheep: wool production
Canterbury New Zealand Sheep and Cattle rearing
Merino sheep: wool production
Savannah Africa and Australia
Taiga Europe and Asia
Selvas South America
Campos South America (Brazil)
Llanos South America (Venezuela)

7) Desert

Desert, any large, extremely dry area of land with sparse vegetation.

Deserts cover more than one-fifth of the Earth's land area, and they are found on every continent. A place that receives less than 25 cm of rain per year is considered a desert.

Deserts are part of a wider class of regions called drylands. These areas exist under a "moisture deficit,"" which means they can frequently lose more moisture through evaporation than they receive from annual precipitation.

The largest hot desert in the world, northern Africa's Sahara, reaches temperatures of up to 50 degrees Celsius during the day. But some deserts are always cold, like the Gobi desert in Asia and the polar deserts of the Antarctic and Arctic, which are the world's largest. Others are mountainous.

Only about 20 percent of deserts are covered by sand.

Chile's Atacama Desert is the driest place on earth, other than the poles. It receives less than 1 mm of precipitation each year, and some areas haven't seen a drop of rain in more than 500 years.

Deserts support only extremely sparse vegetation; trees are usually absent and, under normal climatic conditions, shrubs or herbaceous plants provide only very incomplete ground cover.

The flora is drought resistance such as cactus, euphorbias, sagebrush. Fauna: Reptiles, Small Mammals and birds.

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