Grasslands are the areas where the vegetation is mainly dominated by grasses. Along with grasses, Cyperaceae, Juncaceae, legumes, and other herbs also occupy a certain percentage of various grasslands. Grasslands also compose a major part of the land, dominating the Earth’s landscapes which make it one of the largest biomes. 31% to 43% of Earth’s surface is dominated by grasslands. Except for Antarctica, grasslands occur naturally everywhere else.

There are three major classifications of grasslands. They are as follows:-

Natural Grasslands- Areas with herbaceous vegetations are known as natural grasslands. They cover at least 50% of the Earth’s surface. The maximum height of these herbs is 150 cm. The dominating species covering these grasslands are the Gramineous species. Other than herbaceous vegetation, natural grasslands also have certain areas covered with shrubs, scattered trees, and mineral outcrops. These grasslands are formed under nature conservation.

The term “natural” in this context refers to the vegetation that does not undergo any human interference such as mowing, drainage, irrigation, fertilization, and so on. In these natural grasslands, nothing should interfere with the growth of the grasslands. The natural development of the area should be devoid of any human interference. The only human interference in the maintenance of the grasslands by clearance of weeds and wood overgrowth.

Semi-Natural Grasslands- A semi-natural grassland, also known as a lowland semi-natural grassland refers to grassland that has not been in contact with fertilizers or herbicides. They are called lowland because they exist at an altitude less than 350 metres. Meadow and pasture lands are generally categorised under this type of grasslands. They have partly formed due to human activity such as forest clearings, livestock cutting, and clearing of scrubs and so on. These ultimately led to highly dense areas becoming a grassland.
Agricultural Grasslands- Agricultural grasslands are those grasslands that are designated for the production of forage for harvest. This is done by cutting, grazing, browsing, and so on. These lands are also used for several other agricultural purposes like renewable energy and more. Legumes, grasses, other grass-like plants, forbs and so on are a part of these agricultural grasslands.

Evolution and History of Grasslands

The occurrence of the first true grasslands dates back to around five million years ago. The period is referred to here is the Pliocene epoch in the old world and also known as the Late Miocene period in the new world. The grasslands became much more widespread due to the declination of existing forest biomes. It is a widely known fact that throughout the Pleistocene, the grasslands have existed in Europe. This refers to the last 1.8 million years. After the Pleistocene ice ages, the expansion of grasslands took place. Throughout the hotter, drier climates, these grasslands began to expand. Following this, grasslands became a dominating land feature worldwide. The high variability of the grasslands is due to their existence for over 1.8 million years.

When humans started farming, that was when the semi-natural grasslands first started appearing. Forests were cleared up in Europe for the purpose of agriculture. The parts that were suitable for cultivation were pastures and ancient meadows. The formation of semi-natural grasslands took place in these areas. The coexistence of other plant species around these areas was caused by the removal of plants by grazing animals and by the mowing farmers later. This is the way the evolution of the biodiversity of plants takes place. The new conditions were also already adopted by the species that already lived there.

Arable fields have been created from most of the grassland areas. These fields have disappeared again.

These days, the suitable locations for semi-natural grasslands are generally areas that are unsuitable for agricultural farming.

Grassland Vegetation

The vegetation in grassland could vary in size from very tall to very short. Chalk grassland is an example of short grassland while African savanna, South American grasslands, North American tallgrass prairie constitute some of the tall grasslands.
(Savannas: Some grasslands which contain woody plants, shrubs or trees are called savannas)

Climate

Grasslands are most commonly found in regions with annual precipitation between 600 nm and 1500nm and average mean precipitation which ranges from -5 and 20 °C. However, there are certain grasslands that occur in much colder (−20 °C) and hotter climatic conditions (30 °C). Grasslands have the ability to exist in regions that are frequently disturbed by grazing or fire

Grassland can exist in habitats that are frequently disturbed by grazing or fire, as such disturbance prevents the intrusion of wooden species. It is also observed that there is an increased richness in grasslands of low fertility such as calcareous grasslands and serpentine barriers. This may inhibit the growth of forest and shrub species.

Biodiversity and Conservation

Unimproved grasslands are those which are dominated by unsown wild plant communities. They can also be called natural or semi-natural habitats. Semi-natural is the most common grassland in the temperate regions, here the plant communities are natural, maintaining these plants by different man-made activities such as low-intensity farming, which maintain these grasslands through cutting and grazing regimes.

A good number of different types of species are found in the unimproved grasslands; 25 or more species are present per square metre. Eg: The Chalk downlands in England can support over 40 species per square metre.

On the other hand, agriculturally improved grasslands, which dominate the majority of the agricultural landscapes, tend to have a lesser number of wild species as the original diversity of plants have been destroyed by cultivation. The original wild-plant community has been replaced by different varieties of cultured plants like varieties of grasses and clovers.

Unimproved grasslands are one of the most endangered habitats due to the presence of original wild species. These grasslands are also the target of many wildlife conservation groups or landowners who wish to manage them appropriately.

Human Impact and Economic Importance

Grassland vegetation continues to be dominant in certain areas mainly due to grazing, cutting or natural and man-made fires which discourage the growth of shrubs and trees. The largest grasslands are the African savannas which are maintained by the pastoralists with the help of their cattle, goats, and sheep as well as other wild herbivores.

Grasslands can either occur naturally or as a result of human activity. Grasslands that are created by human activities are called anthropogenic grasslands. These are also maintained and taken care of by humans. Hunting cultures have resulted in regular fires which prevent the growth of fire-intolerant trees and shrubs and maintain and extend grasslands.

Types of Grasslands

There are a variety of classifications of grasslands put forwards by different people :

Schimper (1898): According to Schimper, the different types of grasslands are-

Meadow
Steppe
Savannah

Ellenberg and Mueller: Dombois (1967): According to Ellenberg and Mueller -Dombois the different types of grasslands are :

Savannas and related grasslands
Steppes and related grasslands
Meadows, pastures and related grasslands
Sedge swamps and flushes
Herbaceous and half-woody salt swamps
Forb vegetation

Laycock (1979): According to Laycock the different types of grasslands are :

Tallgrass prairie
Shortgrass prairie
Mixed-grass prairie
Shrub-steppe
Annual grassland
Desert grassland
High mountain grassland

Other Types of Grasslands

Tropical and subtropical grasslands

Tropical and subtropical grasslands or savannas mainly consist of trees and grasses and their proportion varies depending on the rainfall. They are widespread in Africa and occur in all continents except for Antarctica. It is the home for the primates for Asia, Africa and southern

Temperate grasslands

Temperate grasslands consist of different species of grasses and shrubs. Some species of grasses grown in the temperate grasslands include wild oats, foxtail and buffalo grass. The climate in the temperate region varies from semi-arid to semi-humid grasslands. Temperate grasslands are also home to a wide large variety of organisms like large herbivores, such as bison, zebras, wild horses, and many others. Carnivores like lions, cheetah are also found in temperate grasslands.

Flooded grasslands

Flooded grasslands consist of large expanses or complexes of flooded grasslands. Such an environment helps in accommodating plants and animals adapted to the unique hydrologic regime and soil conditions. Flooded grasslands and savannas is a terrestrial habitat type of the WWF biogeographical system, consisting of large expanses or complexes of flooded grasslands. These areas support numerous plants and animals adapted to the unique hydrologic regimes and soil conditions. We could also find a large congregation of migratory as well as residential water birds in flooded grasslands. These grasslands occur mainly in the tropic and the sub-tropics. Water Meadows are grasslands that are flooded for a short period of time.

Montane

Montane grasslands include high altitude grasslands and shrublands. The word “montane” refers to high altitude. They usually occupy the top high mountain ranges of the world. Some montane forests constitute the tundra.

Tundra Prairies

Tundra prairies are similar to montane grasslands

Desert Grasslands

They are also referred to as desert and xeric grasslands. These grasslands are characterised by their warm, humid summers with moderate rain and cold, dry winters. Compared to prairie grasslands the grasses in desert grasslands are shorter, less dense and scattered between succulent and desert shrubs.

Animals

Different types of grasslands support a wide variety of mammals, reptiles, birds, and insects. In undisturbed grasslands mites, insect larvae, nematodes, and earthworms occupy deep soil and can reach up to 6 meters underground. They extend the root systems along with fungi which break apart the hard soil and enrich it with urea and other natural fertilisers, trap minerals and water minerals and promote growth. Grassland is a product of animal behaviour and movement, some examples are the migratory herd of African bush elephants which eat the acacia saplings before they grow into a mature tree.