The grasslands or grasslands are natural ecosystems or those of anthropic origin dominated by grasses that serve as grass, that is, they are food for herbivores. Grasses are generally herbs of the grass family (Poaceae) and it is estimated that grasslands occupy a quarter of the land.
These ecosystems have a simple structure, with a herbaceous layer of a few centimeters to 5 meters high covering the ground. Some types of grasslands include scattered shrubs and trees.
They develop in highly variable soils, depending on the geographical and physiographic area. In the case of cultivated pastures, fertilizer and agrochemical supplements are applied to control pests..
Grasslands derive their name from the coevolutionary relationship they have had with herbivorous mammals. In this relationship, the dominant grasses or grasses are grasses, which have developed different adaptations.
Within these adaptations are underground vegetative propagation structures such as rhizomes, stolons and underground buds. In such a way that when herbivores consume the aerial part of the plant, it can re-sprout.
The grasslands are classified in the first term in two great types that are the natural and cultivated. Among the former are temperate grasslands or prairies, tropical and subtropical or savannas, and mountain ranges..
Grasslands include North American grasslands, South American pampas, Eurasian steppes, and South African veld.
Savannas cover a complexity of types depending on the criteria used for their classification. These tropical grasslands extend widely across America, Africa, the foothills of the Himalayas, and northern Australia..
On the other hand, cultivated grasslands include grasslands proper (herbivore rearing) and other cultivated areas of grass for different purposes..
Natural grasslands vary in relief from very flat areas, through hilly areas, plateaus, to high mountain terrain. While cultivated grasslands can be adapted to the natural relief or mechanically leveled to facilitate agricultural work.
In the grasslands the flora is varied with a predominance of grass species in the herbaceous stratum. When there are trees, they belong to different families and legumes predominate in the tropical zone and phagaceae in temperate ones..
As for the fauna, it can be scarce or very abundant, as in the case of the African savannas. In these there is a great diversity of large herbivorous mammals (wildebeest, zebras, gazelles) and large carnivores (lions, leopards, hyenas).
In the prairies of North America live the buffalo and the water puppy and in South America the jaguar and the capybara. In the Indo-Malaysian region the one-horned rhinoceros and the tiger and in the Asian steppe the saiga antelope.
On the other hand, in cultivated grasslands most of the wild fauna has been displaced for the benefit of domesticated animals. Among the latter we have cattle, sheep and pigs.
The predominant economic activity in the grasslands is the rearing of these types of cattle. Also large areas are dedicated to the cultivation of cereals and other items as well as tourism.
Prominent examples of the world's grasslands are the US corn belt o Corn Belt, the pampas in South America and the African savannas.
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Natural grasslands encompass two major terrestrial biomes, savannas and grasslands (including pampas, steppes, and veld). Together these biomes include 94 ecoregions according to the World Wildlife Foundation o World Wildlife Fund (WWF).
Although in most cases cultivated grasslands are established in natural grassland areas, this is not always the case. Many cultivated grasslands develop in areas of deforested forest.
For example, large areas of grasslands in the western Venezuelan plains are in areas of former semi-deciduous tropical forests. Likewise, much of the Brazilian Amazon rainforest is being deforested to establish grasslands for livestock production..
On the other hand, in temperate zones the grasslands have also expanded their limits at the expense of the deciduous forest.
A grassland, natural or cultivated, has a simple structure with a herbaceous layer covering the ground and few or no shrubs and trees. There are some formed exclusively by a cover of grasses, continuous (tussock species) or discontinuous (tuft or tuft species).
However, there are also grasslands with scattered trees or shrubs, in greater or lesser density, such as the acacia savannas in Africa.
In the case of cultivated grasslands, large tracts of a single grass species are typically grown without trees. However, there are systems where the presence of the arboreal element is important.
For example, in mixed grass-legume pastures and silvopastoral systems such as dehesas.
The soils of the grasslands are highly variable, since it depends on the region where they are developed. For example, prairie soils are generally more fertile and deeper than those of tropical savannas..
In those grasslands established on soils previously occupied by temperate deciduous forests or semi-deciduous tropical forests, fertility is usually high. While the soils of the Amazon rainforest deforested and converted to pasture, it requires a lot of supplementation of fertilizers.
Due to the high combustion of dry matter in grasses, fire is usually a factor present in grasslands. In fact, grasses have developed structures to support both herbivory and fire..
In cultivated pastures, the aim is to avoid both drying out and burning of the pastures. In many cases the pastures are supplemented with irrigation, either by sprinkling or by furrows.
Grasslands are linked to herbivory, and both plants and herbivores have evolved in this regard. Grasses have developed various subsurface vegetative propagation structures.
Among them the rhizomes, stolons and underground buds, which allow them to sprout once the aerial part has been consumed. For their part, herbivorous mammals have adequate anatomy and physiology to ingest grasses and digest the predominant cellulose.
In nature, large herbivores move following migratory patterns in search of grasslands. On the other hand, in grasslands where large herds of different species feed, as in Africa, there is a specialization by niches.
This means that each species feeds on a part of the plant or on certain species. In this way, competition for food is reduced and the potential of the pasture is exploited..
In the case of cultivated pastures, it is the human being who must regulate the grazing load to which the agricultural ecosystem is subjected. Load refers to the number of animals per unit area.
This load is a function of the type of animal, species of pasture and extension of the land. If subjected to an excessive animal load, the pasture is depleted and the soil is compacted by trampling.
In America are the North American grasslands, stretching from the Rocky Mountains in the west to the Atlantic deciduous forests in the east. Then there are the pampas and the Patagonian steppes in the southern cone of South America.
In Europe, the Eurasian grasslands and steppes stretch from the Iberian Peninsula to the Far East. While in Africa there are the South African veld and in Oceania the Australian temperate savannas.
Taking into account all these ecosystems, in total there are 44 ecoregions of temperate grasslands or prairies.
In the tropics and subtropics there are savannas that are diversified into 50 ecoregions. In Africa they range from the Atlantic coast to the Indian Ocean in a large sub-Saharan strip, and then to the southeast.
In America they are found in the south of North America, Central America and North of South America and further south, the large savannas of the Cerrado extend. Similarly, there are savannas in the foothills of the Himalayas, and in the north and northeast of Australia..
The savannas can be classified into different types according to various criteria and due to the water regime there are floodable and non-floodable savannas. Likewise, there are seasonal savannas (4-6 months dry season), hyperstational (3-4 months) and semi-seasonal (few weeks).
Likewise, according to the physiognomy of the plant formation, there are ungrove savannas (without trees) and wooded savannas.
The establishment of a cultivated pasture depends on the region, the climate, the soils and the animal species to be produced. There are different production systems, whether the animals graze on the land or the grass is cut (forage).
On the other hand, as in natural pastures in cultivated ones there are systems without trees and others that have an arboreal layer.
Although the word “paddock” refers to a pasture for horse breeding, in Latin America the term is broader. The paddock is a plot of delimited land where cattle are fed, be it horse, bovine or other.
Whether it consists of introduced or native grasses, the paddock is a pastureland with agronomic management. This management includes the selection of pastures, weed control and fertilization among other aspects..
For its part, the "meadow" refers to a land with natural humidity or under irrigation, where grasses are grown for livestock. The meadows develop in flat or slightly undulating places in areas of humid climate and cool temperatures.
They are common in mountain livestock areas both in temperate regions and in temperate zones of the tropical zone..
In the tropical grasslands of America it is common to maintain an arboreal layer, mainly leguminous trees. These trees fulfill the function of providing shade for livestock in these regions of high solar radiation..
They also provide additional proteins to animal nutrition through their fruits. Some trees used for this purpose are saman (Samanea saman), the guanacaste or caro-caro (Enterolobium cyclocarpum) and the American carob (Hymenaea courbaril).
Another system that forms wooded pastures are the so-called silvopastoral fields that combine pastures with fruit and timber trees and that produce cork, pulp and other products. These systems are established in two basic ways that are clearing a forest and cultivating grass or planting trees in a pasture..
In tropical America timber species such as teak (Tectona grandis), American cedar (Cedrela odorata) and mahogany (Swietenia macrophylla).
In temperate zones there are dehesas that are grasslands established in cleared Mediterranean forest (partially deforested with trees alternated with open spaces). Common tree species in the dehesa are the European cork oak (Quercus risesr) and holm oak (Quercus ilex).
In these spaces pasture is cultivated in order to feed the cattle that are kept in the pasture, such as cattle and pigs. An example of the latter is the Iberian pig rearing that feeds on acorns fallen from holm oak trees..
The plant is cultivated on cut pastures and then cut and fed to the animals in pens or stables. These cutting grasses can also be ensiled for enrichment and later use..
The lawn is a type of grass pasture that covers the entire soil thanks to its growth by stolons or rhizomes. These are modified stems that extend superficially or underground and generate successive shoots.
The grass is used for ornamental purposes in gardens or for sports fields. Short-growing species are required, which generate a dense and green cover.
Some grasses to form lawns are the Cumberland (Agrostis stolonifera), red cañuela (Fescue rubra) and English grass (Perennial lolium) in temperate zones.
While in tropical areas there are the San Agustín grass (Stenotaphrum secundatum), Bermuda grass (Cynodon dactylon) and the kikuyo (Pennisetum clandestinum).
A classification criterion common to all types of grasslands is that given by the height of the grass. In this case we speak of both prairies, savannas or cultivated pastures of short or low, medium and tall grass..
This is determined by the dominant grass species, which depend on regional, climatic and soil conditions..
In the case of cultivated grasslands, tall grasses are generally used for cutting and silage.
Grasslands, whether natural or cultivated, are mostly found on flat to undulating terrain. However, they also develop in mountainous areas and plateaus.
They are even located in areas below sea level (-100 masl), such as the Colombian-Venezuelan plains up to 4,000 masl. (high mountain pastures).
Grasses of the Arundinoideae and Pooideae subfamilies predominate in the prairies, and Chloridoideae and Panicoideae abound in the savannas.
Species of the genera Poa, Fescue, Lolium Y Stipa.
Among the most common genera of grasses in the savannas are Trachypogon, Paspalum, Panicum Y Tridens, Aristida, Axonopus Y Pennisetum.
The main species of grasses cultivated in temperate floors belong to the genera Fescue Y Lolium. Among the most used species are Perennial lolium (English ryegrass, perennial), Lolium multiflorum (Italian ryegrass, annual) and Festuca arundinacea.
Other important species are Kentucky bluegrass (Poa pratensis) and the falaris (Phalaris tuberosa) frost resistant.
Among the evergreen grasses are elephant grass (Pennisetum purpureum), and Mombaza grass or gamelote (Panicum maximum). Both native species from Africa, but naturalized in tropical America.
A genus widely used as grassland is Brachiaria, with species like Brachiaria brizantha, B. decumbens, Brachiaria dictyoneura Y B. humidicola. The species Brachiaria humidicola is native to Africa but is widely used as grass in America and Asia.
In the search to improve pastures for livestock, humans have transferred species from one ecoregion to another. In many cases these species invade natural spaces and adapt to local conditions. This represents a problem since they compete with the wild flora of the localities..
For example, in tropical America many species of African grasses have been introduced, which under conditions similar to those of their natural habitat become naturalized. An example is the mountain pastures of Capín Melao (Melinis minutiflora) in the EL Ávila National Park in Caracas (Venezuela).
This African species has become naturalized not only in Venezuela but also in Colombia, Brazil and even Hawaii.
In the prairies the climate is mild and dry for most of the year, the summers are warm and the winters are relatively cold to very cold (steppe). Temperatures range from 0 ºC in winter to 25 ºC in summer, with annual rainfall of 300 to 1,000 mm..
For their part, the savannas develop in a bi-seasonal climate with variable rainfall, from 600 to 3,000 mm with an average annual temperature of 27 ºC. The dry season can last from 3 to 7 months, and the rest of the year corresponds to the rainy season.
In most cases, grasslands are the habitat of many herbivorous animal species. In certain regions these species make up huge populations and in others there were large populations that are currently diminished..
Millions of buffaloes or American bison (Bison bison). Today it is a species in recovery, but it almost came to extinction due to hunting.
There are also large colonies of prairie dogs (Cynomys spp.) that reach thousands and even millions of individuals.
The Saiga antelope (Saiga tatarica) and the Mongolian horse (Equus ferus).
In the veld we find the Cape jumping gazelle or springbok (Antidorcas marsupialis) and to the cuaga (Equus quagga).
The highest concentrations of large herbivores are found in the African savannas. Herds of millions of blue wildebeest (Connochaetes taurinus) and Burchell's zebras (Equus burchelli).
Kaffir buffalo also inhabit (Syncerus caffer), elephants (Loxodonta africana), giraffes (Giraffa camelopardalis), hippos (Hippopotamus amphibius) and numerous birds.
Associated with these concentrations of herbivores are large carnivores such as the lion (Panthera leo) and the leopard (Panthera pardus pardus).
In this region at the foot of the Himalayas is the largest concentration of tigers, rhinos and ungulates in Asia such as the one-horned rhinoceros (Rhinoceros unicornis) and the tiger (Panthera tigris). Among the ungulates are the nilgó or blue bull (Boselaphus tragocamelus) and the water buffalo (Bubalus arnee).
Capybaras (Hydrochoerus hydrochaeris), deer (Odocoileus virginianus apurensis) and jaguars (Panthera onca). In addition to anacondas (Eunectes murinus) and Orinoco alligators (Crocodylus intermedius) in its rivers.
Grasslands, whether natural or cultivated, are dedicated to the breeding of different animal species that have been domesticated since ancient times. Among the domesticated species raised in the grasslands are cattle, sheep and pigs.
This is a good example of the adaptation of the grassland ecosystem to human production. Most of the cattle produced correspond to subspecies of the wild species Bos primigenius primigenius.
This species existed in the grasslands and forests of Eurasia until the seventeenth century, but sadly it was extinguished by hunting..
Two subspecies were derived from it, which are the basis of practically all beef production. These are Bos primigenius taurus, typical of temperate floors, and Bos primigenius indicus, more adapted to tropical climate.
The rearing of bovines, either for the production of meat, milk or dual purposes, is carried out under various systems. They can be raised in stables, that is, in stables providing them with forage, or extensively by letting them feed in the pastures.
As with cattle, sheep farming comes from the domestication of a wild species. In this case, the most frequent species in production is Ovis orientalis, specifically the subspecies Ovis orientalis aries.
According to recent studies, the ancestor of this subspecies is the Asian mouflon (Ovis orientalis orientalis). This species is currently restricted to the high mountain grassland of the Caucasus, central Asia and some parts of Turkey..
The domestic pig (Sus scrofa domestica) derives from wild pig or wild boar (Sus scrofa scrofa). They are omnivorous animals, that is, they feed on both plants and animals (insects, worms, carrion).
Its natural habitat is the forest, however the domestic pig has been adapted to breeding in open areas.
Pig production systems are varied, although in general there are stables (pigs). However, there are mixed and grazing production systems, an example of the first is the Iberian pig.
This pig is reared in two phases, a first where it is fed in pig pens and the other for final fattening in pastures. The latter is the so-called montanera period and they feed mainly on the acorns of the holm oaks.
In the strict grazing system, the pigs are raised in paddocks conditioned for each phase. These are insemination, gestation, childbirth and rearing and it is considered a more ecological and economical system than pig breeding..
The main economic activities in grasslands are linked to the grassland-herbivore biological relationship. In this sense, they are ideal places for the production of domestic herbivores such as cows, sheep and pigs..
Most of the beef production is generated in grasslands and savannas such as the North American prairies, savannas and South American pampas. There is also cattle production in the Eurasian grasslands and steppes and the Australian grasslands.
On the other hand, both natural and human-made grasslands are suitable places for cultivation. Although some savannas and grasslands are of low fertility, there are other areas with good soils for agriculture.
The most fertile soils are in grasslands such as natural prairies or those caused by degradation of deciduous forests. In the case of the savannas, the best soils are in the undulating foothills.
Likewise, secondary savannas originated by deforestation of semi-deciduous forests have adequate soil fertility..
Crops grown on grasslands include wheat, maize, and rye in temperate zones. While maize, sorghum and rice predominate in tropical and subtropical areas.
Silvopastoral systems are established in grassland areas that allow livestock production and obtaining forest products. In these systems, wood, pulp for paper, fruits, resins, cork and other products are obtained..
In some savannas, even with poor soils, forest plantations can be established such as the Uverito pine plantations, located in the Mesa de Guanipa (Venezuela). It is the largest artificial forest plantation in the world, with about 600,000 hectares.
Conservation areas, such as national parks and wildlife reserves, have been established in many areas of natural grasslands. In these areas the fundamental economic activity is tourism.
Even in pastures intervened by human beings and dedicated to agricultural production, today agro-tourism is developed. In this type of tourism, life and tasks in the countryside are experienced, while interacting with nature.
One of the activities traditionally carried out in the grasslands is hunting. The most prominent case is the African savannas, given the abundance of game animals..
This is the name given to a large region of the United States that develops in tall grass prairie lands. This region is located in the northeast quadrant of the North American country and there is produced more than 40% of the corn of this country.
The US is the world's largest corn producer thanks to this region, but cattle and pigs are also produced.
They are the grasslands that extend through Uruguay, the state of Rio Grande do Sul and the western central region of Argentina. The grasslands of this region support one of the largest grain and meat productions in the world.
Among the cereal crops grown in the pampas are wheat, corn, barley, and sorghum. In addition, sunflower, peanut and potato are produced and in recent years soy is reaching a great boom.
Regarding animal production, cattle, sheep and pigs are produced in the pampas. In Brazil there are more than 200 million head of cattle, in Argentina 50 million and in Uruguay more than 11 million.
It is the world's best example of grasslands, not only because of its size, but also because of the diversity of large herbivores it houses. Especially the acacia wooded savannas of Kenya and Tanzania where there are millions of wildebeest and hundreds of thousands of zebras and antelopes.
In association with these concentrations of herbivores, large carnivores such as the lion, the hyena and the leopard are present..
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