Grasslands are the areas where the vegetation are mainly dominated by grasses. Except for Antarctica, grasslands occur naturally everywhere else.
There are three different types of grasslands :
1. Temperate grasslands
3. Shrublands biomes
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]
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 which 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 which 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 that which are dominated by unsown wild plant communities. They can also be called natural or semi-natural habitat. 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 meter. Eg: The Chalk downlands in England can support over 40 species per square meter.
On the other hand, agriculturally improved grasslands, which dominate the majority of the agricultural landscapes, tend to have 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species as the original diversity of plants have been destroyed by cultivation,.The original wild-plant community has been replaced by different varieties of cultured plants like varieties of grasses and clovers.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 to 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 which 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 maintains and extends grasslands.
TYPES OF GRASSLANDS
There are a variety of classifications of grasslands put forwards by different people :
1)Schimper (1898): According to Schimper the different types of grasslands are :
2)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
3)Laycock (1979): According to Laycock the different types of grasslands are :
• Tallgrass prairie
• Shortgrass prairie
• Mixed-grass prairie
• Annual grassland
• Desert grassland
• High mountain grassland
OTHER TYPES OF GRASSLANDS
1)Tropical and subtropical grasslands
Tropical and subtropical grasslands or savannas mainly consists of trees and grasses and their proportion varies depending on the rainfall. They are widespread in Africa and occurs in all continents except for Antarctica. It is the home for the primates for Asia, Africa and southern
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 herbivorous, such as bison, zebras, wild horses, and many others. Carnivores like lions, cheetah are also found in temperate 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 a flooded for a short period of time.
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 montanes constitute the tundra.
Tundra prairies are similar to montane grasslands
They are also referred to as desert and xeric grasslands. These grasslands are characterized by their warm, humid sy=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.
Different types of grasslands support a wide variety of mammals, reptiles, birds, and insects.IN undisturbed grasslands mites, insect larvae, nematode, and earthworms occupy deep soil and can reach up to 6 meters underground. They extend the root systems along with fungi which breaks apart the hard soil and enrich it with urea and other natural fertilizers, trap minerals and water minerals and promote growth. Grassland is a product of animal behavior and movement, some examples are the migratory herd of African bush elephants which eating the acacia saplings before they grow into a mature tree.