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Grasslands are areas where the vegetation is dominated by grasses (Poaceae); however, sedge (Cyperaceae) and rush (Juncaceae) families can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur naturally on all continents except Antarctica. Grasslands are found in most ecoregions of the Earth. For example, there are five terrestrial ecoregion classifications (subdivisions) of the temperate grasslands, savannas, and shrublands biome (ecosystem), which is one of eight terrestrial ecozones of the Earth's surface.
Vegetation is an assemblage of plant species and the ground cover they provide. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characteristics. It is broader than the term flora which refers to species composition. Perhaps the closest synonym is plant community, but vegetation can, and often does, refer to a wider range of spatial scales than that term does, including scales as large as the global. Primeval redwood forests, coastal mangrove stands, sphagnum bogs, desert soil crusts, roadside weed patches, wheat fields, cultivated gardens and lawns; all are encompassed by the term vegetation.
Poaceae or Gramineae is a large and nearly ubiquitous family of monocotyledonous flowering plants known as grasses, commonly referred to collectively as grass. Poaceae includes the cereal grasses, bamboos and the grasses of natural grassland and cultivated lawns and pasture. Grasses have stems that are hollow except at the nodes and narrow alternate leaves borne in two ranks. The lower part of each leaf encloses the stem, forming a leaf-sheath. With around 780 genera and around 12,000 species, Poaceae are the fifth-largest plant family, following the Asteraceae, Orchidaceae, Fabaceae and Rubiaceae.
The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges, which superficially resemble the closely related rushes and the more distantly related grasses. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus Carex with over 2,000 species. These species are widely distributed, with the centers of diversity for the group occurring in tropical Asia and tropical South America. While sedges may be found growing in almost all environments, many are associated with wetlands, or with poor soils. Ecological communities dominated by sedges are known as sedgelands.
Grassland vegetation can vary in height from very short, as in chalk grassland, to quite tall, as in the case of North American tallgrass prairie, South American grasslands and African savanna.
Calcareous grassland is an ecosystem associated with thin basic soil, such as that on chalk and limestone downland. Plants on calcareous grassland are typically short and hardy, and include grasses and herbs such as clover. Calcareous grassland is an important habitat for insects, particularly butterflies, and is kept at a plagioclimax by grazing animals, usually sheep and sometimes cattle. Rabbits used to play a part but due to the onset of myxomatosis their numbers decreased so dramatically that they no longer have much of a grazing effect.
North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It is also considered by some to be a northern subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea.
The Tallgrass prairie is an ecosystem native to central North America. Natural and anthropogenic fire, as well as grazing by large mammals, were historically agents of periodic disturbance, which regulates tree encroachment, recycles nutrients to the soil, and catalyzes some seed dispersal and germination processes. Prior to widespread use of the steel plow, which enabled conversion to agricultural land use, tallgrass prairies expanded throughout the American Midwest and smaller portions of southern central Canada, from the transitional ecotones out of eastern North American forests, west to a climatic threshold based on precipitation and soils, to the southern reaches of the Flint Hills in Oklahoma, to a transition into forest in Manitoba.
Woody plants, shrubs or trees may occur on some grasslands – forming savannas, scrubby grassland or semi-wooded grassland, such as the African savannas or the Iberian dehesa.
As flowering plants and trees, grasses grow in great concentrations in climates where annual rainfall ranges between 500 and 900 mm (20 and 35 in). The root systems of perennial grasses and forbs form complex mats that hold the soil in place.
Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, plants were treated as one of two kingdoms including all living things that were not animals, and all algae and fungi were treated as plants. However, all current definitions of Plantae exclude the fungi and some algae, as well as the prokaryotes. By one definition, plants form the clade Viridiplantae, a group that includes the flowering plants, conifers and other gymnosperms, ferns and their allies, hornworts, liverworts, mosses and the green algae, but excludes the red and brown algae.
Climate is defined as the average state of everyday's weather condition over a period of 30 years. It is measured by assessing the patterns of variation in temperature, humidity, atmospheric pressure, wind, precipitation, atmospheric particle count and other meteorological variables in a given region over long periods of time. Climate differs from weather, in that weather only describes the short-term conditions of these variables in a given region.
Rain is liquid water in the form of droplets that have condensed from atmospheric water vapor and then become heavy enough to fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides suitable conditions for many types of ecosystems, as well as water for hydroelectric power plants and crop irrigation.
The grass-like graminoids are among the most versatile life forms. They became widespread toward the end of the Cretaceous period, and coprolites of fossilized dinosaur feces have been found containing phytoliths of a variety of grasses that include grasses that are related to modern rice and bamboo.
In botany and ecology, graminoid refers to a herbaceous plant with a grass-like morphology, i.e. elongated culms with long, blade-like leaves. They are contrasted to forbs, herbaceous plants without grass-like features.
In biology, an organism is any individual entity that exhibits the properties of life. It is a synonym for "life form".
The Cretaceous is a geologic period and system that spans 79 million years from the end of the Jurassic Period 145 million years ago (mya) to the beginning of the Paleogene Period 66 mya. It is the last period of the Mesozoic Era, and the longest period of the Phanerozoic Eon. The Cretaceous Period is usually abbreviated K, for its German translation Kreide.
The appearance of mountains in the western United States during the Miocene and Pliocene epochs, a period of some 25 million years, created a continental climate favorable to the evolution of grasslands. Existing forest biomes declined, and grasslands became much more widespread. Following the Pleistocene ice ages, grasslands expanded in range in the hotter, drier climates, and began to become the dominant land feature worldwide.
The Western United States is the region comprising the westernmost states of the United States. As European settlement in the U.S. expanded westward through the centuries, the meaning of the term the West changed. Before about 1800, the crest of the Appalachian Mountains was seen as the western frontier. The frontier moved westward and eventually the lands west of the Mississippi River were considered the West.
The Miocene is the first geological epoch of the Neogene Period and extends from about(Ma). The Miocene was named by Charles Lyell; its name comes from the Greek words μείων and καινός and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene is preceded by the Oligocene and is followed by the Pliocene.
The Pliocene Epoch is the epoch in the geologic timescale that extends from 5.333 million to 2.58 million years BP. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch. Prior to the 2009 revision of the geologic time scale, which placed the four most recent major glaciations entirely within the Pleistocene, the Pliocene also included the Gelasian stage, which lasted from 2.588 to 1.806 million years ago, and is now included in the Pleistocene.
Grasslands often occur in areas with annual precipitation is between 600 mm (24 in) and 1,500 mm (59 in) and average mean annual temperatures ranges from −5 and 20 °C (Woodward et al. 2004). However, some grasslands occur in colder (−20 °C) and hotter (30 °C) climatic conditions. Grassland can exist in habitats that are frequently disturbed by grazing or fire, as such disturbance prevents the encroachment of woody species. Species richness is particularly high in grasslands of low soil fertility such as serpentine barrens and calcareous grasslands, where woody encroachment is prevented as low nutrient levels in the soil may inhibit the growth of forest and shrub species.
Grasslands dominated by unsown wild-plant communities ("unimproved grasslands") can be called either natural or "semi-natural" habitat. The majority of grasslands in temperate climates are "semi-natural". Although their plant communities are natural, their maintenance depends upon anthropogenic activities such as low-intensity farming, which maintains these grasslands through grazing and cutting regimes. These grasslands contain many species of wild plants, including grasses, sedges, rushes, and herbs; 25 or more species per square meter is not unusual.[ citation needed ] Chalk downlands in England can support over 40 species per square meter. In many parts of the world, few examples have escaped agricultural improvement (fertilizing, weed killing, plowing or re-seeding). For example, original North American prairie grasslands or lowland wildflower meadows in the UK are now rare and their associated wild flora equally threatened. Associated with the wild-plant diversity of the "unimproved" grasslands is usually a rich invertebrate fauna; there are also many species of birds that are grassland "specialists", such as the snipe and the great bustard. Agriculturally improved grasslands, which dominate modern intensive agricultural landscapes, are usually poor in wild plant species due to the original diversity of plants having been destroyed by cultivation, the original wild-plant communities having been replaced by sown monocultures of cultivated varieties of grasses and clovers, such as perennial ryegrass and white clover. In many parts of the world, "unimproved" grasslands are one of the most threatened types of habitat, and a target for acquisition by wildlife conservation groups or for special grants to landowners who are encouraged to manage them appropriately.
Grassland vegetation often remains dominant in a particular area usually due to grazing, cutting, or natural or man-made fires, all discouraging colonization by and survival of tree and shrub seedlings. Some of the world's largest expanses of grassland are found in the African savanna, and these are maintained by wild herbivores as well as by nomadic pastoralists and their cattle, sheep or goats. Recently, grasslands have been shown to have an impact on climate change by slower decomposition rates of litter compared to forest environments.
Grasslands may occur naturally or as the result of human activity. Grasslands created and maintained by human activity are called anthropogenic grasslands. Hunting cultures around the world often set regular fires to maintain and extend grasslands, and prevent fire-intolerant trees and shrubs from taking hold. The tallgrass prairies in the U.S. Midwest may have been extended eastward into Illinois, Indiana, and Ohio by human agency. Much grassland in northwest Europe developed after the Neolithic Period when people gradually cleared the forest to create areas for raising their livestock.
The professional study of grasslands falls under the category of rangeland management, which focuses on ecosystem services associated with the grass-dominated arid and semi-arid rangelands of the world. Rangelands account for an estimated 70% of the earth's landmass; thus, many cultures including those of the United States are indebted to the economics that the world's grasslands have to offer, from producing grazing animals, tourism, ecosystems services such as clean water and air, and energy extraction.
Grassland types by Schimper (1898, 1903):
Grassland types by Ellenberg and Mueller-Dombois (1967):
Formation-class V. Terrestrial herbaceous communities
Grassland types by Laycock (1979):
These grasslands are classified with tropical and subtropical savannas and shrublands as the tropical and subtropical grasslands, savannas, and shrublands biome. Notable tropical and subtropical grasslands include the Llanos grasslands of South America.
Mid-latitude grasslands, including the prairie and Pacific grasslands of North America, the Pampas of Argentina, Brazil and Uruguay, calcareous downland, and the steppes of Europe. They are classified with temperate savannas and shrublands as the temperate grasslands, savannas, and shrublands biome. Temperate grasslands are the home to many large herbivores, such as bison, gazelles, zebras, rhinoceroses, and wild horses. Carnivores like lions, wolves and cheetahs and leopards are also found in temperate grasslands. Other animals of this region include: deer, prairie dogs, mice, jack rabbits, skunks, coyotes, snakes, fox, owls, badgers, blackbirds (both Old and New World varieties), grasshoppers, meadowlarks, sparrows, quails, hawks and hyenas.
Grasslands that are flooded seasonally or year-round, like the Everglades of Florida, the Pantanal of Brazil, Bolivia and Paraguay or the Esteros del Ibera in Argentina, are classified with flooded savannas as the flooded grasslands and savannas biome and occur mostly in the tropics and subtropics.
Watermeadows are grasslands that are deliberately flooded for short periods.
High-altitude grasslands located on high mountain ranges around the world, like the Páramo of the Andes Mountains. They are part of the montane grasslands and shrublands biome and also constitute tundra.
Similar to montane grasslands, polar Arctic tundra can have grasses, but high soil moisture means that few tundras are grass-dominated today. However, during the Pleistocene glacial periods (commonly referred to as ice ages), a freezing grassland known as steppe-tundra or mammoth steppe occupied large areas of the Northern Hemisphere. These areas were very cold and arid and featured sub-surface permafrost (hence tundra) but were nevertheless productive grassland ecosystems supporting a wide variety of fauna. As the temperature warmed and the climate became wetter at the beginning of the Holocene much of the mammoth steppe transitioned forest, while the drier parts in central Eurasia remained grassland, becoming the modern Eurasian steppe.
Also called desert grasslands, this is composed of sparse grassland ecoregions located in the deserts and xeric shrublands biome.
Mites, insect larvae, nematodes and earthworms inhabit deep soil, which can reach 6 metres (20 ft) underground in undisturbed grasslands on the richest soils of the world. These invertebrates, along with symbiotic fungi, extend the root systems, break apart hard soil, enrich it with urea and other natural fertilizers, trap minerals and water and promote growth. Some types of fungi make the plants more resistant to insect and microbial attacks.
Grassland in all its form supports a vast variety of mammals, reptiles, birds, and insects. Typical large mammals include the blue wildebeest, American bison, giant anteater and Przewalski's horse.
While grasslands in general support diverse wildlife, given the lack of hiding places for predators, the African savanna regions support a much greater diversity in wildlife than do temperate grasslands.
There is evidence for grassland being much the product of animal behaviour and movement;some examples include migratory herds of antelope trampling vegetation and African bush elephants eating acacia saplings before the plant has a chance to grow into a mature tree.
|Al Hajar Al Gharbi montane woodlands||Oman|
|Amsterdam and Saint-Paul Islands temperate grasslands||Amsterdam Island, Saint-Paul Island|
|Tristan da Cunha-Gough Islands shrub and grasslands||Tristan da Cunha, Gough Island|
|Canterbury-Otago tussock grasslands||New Zealand|
|Eastern Australia mulga shrublands||Australia|
|Southeast Australia temperate savanna||Australia|
|California Central Valley grasslands||United States|
|Canadian aspen forests and parklands||Canada, United States|
|Central and Southern mixed grasslands||United States|
|Central forest-grasslands transition||United States|
|Central tall grasslands||United States|
|Columbia Plateau||United States|
|Edwards Plateau savanna||United States|
|Flint Hills tall grasslands||United States|
|Montana valley and foothill grasslands||United States|
|Nebraska Sand Hills mixed grasslands||United States|
|Northern mixed grasslands||Canada, United States|
|Northern short grasslands||Canada, United States|
|Northern tall grasslands||Canada, United States|
|Palouse grasslands||United States|
|Texas blackland prairies||United States|
|Western short grasslands||United States|
|Patagonian grasslands||Argentina, Chile|
|Patagonian steppe||Argentina, Chile|
|Alai-Western Tian Shan steppe||Kazakhstan, Tajikistan, Uzbekistan|
|Altai steppe and semi-desert||Kazakhstan|
|Central Anatolian steppe||Turkey|
|Daurian forest steppe||China, Mongolia, Russia|
|Eastern Anatolian montane steppe||Armenia, Iran, Turkey|
|Emin Valley steppe||China, Kazakhstan|
|Faroe Islands boreal grasslands||Faroe Islands, Denmark|
|Gissaro-Alai open woodlands||Kyrgyzstan, Tajikistan, Uzbekistan|
|Kazakh forest steppe||Kazakhstan, Russia|
|Kazakh steppe||Kazakhstan, Russia|
|Middle East steppe||Iraq, Syria|
|Mongolian-Manchurian grassland||China, Mongolia, Russia|
|Pontic steppe||Kazakhstan, Moldova, Romania, Russia, Ukraine, Bulgaria|
|Sayan Intermontane steppe||Russia|
|Selenge-Orkhon forest steppe||Mongolia, Russia|
|South Siberian forest steppe||Russia|
|Tian Shan foothill arid steppe||China, Kazakhstan, Kyrgyzstan|
|Arnhem Land tropical savanna||Australia|
|Brigalow tropical savanna||Australia|
|Cape York tropical savanna||Australia|
|Carpentaria tropical savanna||Australia|
|Einasleigh upland savanna||Australia|
|Kimberley tropical savanna||Australia|
|Mitchell grass downs||Australia|
|Trans Fly savanna and grasslands||Indonesia, Papua New Guinea|
|Victoria Plains tropical savanna||Australia|
|Terai-Duar savanna and grasslands||Bhutan, India, Nepal|
|Western Gulf coastal grasslands||Mexico, United States|
|Cerrado||Bolivia, Brazil, Paraguay|
|Clipperton Island shrub and grasslands||Clipperton Island is an overseas territory of France|
|Córdoba montane savanna||Argentina|
|Guianan savanna||Brazil, Guyana, Venezuela|
|Gran Chaco||Argentina, Brazil, Paraguay|
|Los Llanos||Venezuela, Colombia|
|Uruguayan savanna||Argentina, Brazil, Uruguay|
|Hawaiian tropical high shrublands||Hawaiʻi|
|Hawaiian tropical low shrublands||Hawaiʻi|
|Northwestern Hawaii scrub||Hawaiʻi|
|Wikimedia Commons has media related to Grasslands .|
A biome is a community of plants and animals that have common characteristics for the environment they exist in. They can be found over a range of continents. Biomes are distinct biological communities that have formed in response to a shared physical climate. Biome is a broader term than habitat; any biome can comprise a variety of habitats.
In physical geography, a steppe is an ecoregion, in the montane grasslands and shrublands and temperate grasslands, savannas and shrublands biomes, characterized by grassland plains without trees apart from those near rivers and lakes. The prairie of North America is an example of a steppe, though it is not usually called such. A steppe may be semi-arid or covered with grass or shrubs or both, depending on the season and latitude. The term is also used to denote the climate encountered in regions too dry to support a forest but not dry enough to be a desert. The soil is typically of chernozem type.
Temperate grasslands, savannahs, and shrublands is a terrestrial habitat type defined by the World Wide Fund for Nature. The predominant vegetation in this biome consists of grass and/or shrubs. The climate is temperate and ranges from semi-arid to semi-humid. The habitat type differs from tropical grasslands in the annual temperature regime as well as the types of species found here.
The Global 200 is the list of ecoregions identified by WWF, the global conservation organization, as priorities for conservation. According to WWF, an ecoregion is defined as a "relatively large unit of land or water containing a characteristic set of natural communities that share a large majority of their species dynamics, and environmental conditions". So, for example, based on their levels of endemism, Madagascar gets multiple listings, ancient Lake Baikal gets one, and the North American Great Lakes get none.
A savanna or savannah is a mixed woodland grassland ecosystem 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.
Tropical and subtropical grasslands, savannas, and shrublands is a terrestrial habitat type defined by the World Wide Fund for Nature.. The biome is dominated by grass and/or shrubs located in semi-arid to semi-humid climate regions of subtropical and tropical latitudes.
Rangelands are grasslands, shrublands, woodlands, wetlands, and deserts that are grazed by domestic livestock or wild animals. Types of rangelands include tallgrass and shortgrass prairies, desert grasslands and shrublands, woodlands, savannas, chaparrals, steppes, and tundras. Rangelands do not include forests lacking grazable understory vegetation, barren desert, farmland, or land covered by solid rock, concrete and/or glaciers.
Aspen parkland refers to a very large area of transitional biome between prairie and boreal forest in two sections, namely the Peace River Country of northwestern Alberta crossing the border into British Columbia, and a much larger area stretching from central Alberta, all across central Saskatchewan to south central Manitoba and continuing into small parts of the US states of Minnesota and North Dakota. Aspen parkland consists of groves of aspen poplars and spruce interspersed with areas of prairie grasslands, also intersected by large stream and river valleys lined with aspen-spruce forests and dense shrubbery. This is the largest boreal-grassland transition zone in the world and is a zone of constant competition and tension as prairie and woodlands struggle to overtake each other within the parkland.
The Texas Blackland Prairies are a temperate grassland ecoregion located in Texas that runs roughly 300 miles (480 km) from the Red River in North Texas to San Antonio in the south. The prairie was named after its rich, dark soil.
California coastal prairie, also known as northern coastal grassland, is a grassland plant community of California and Oregon in the temperate grasslands, savannas, and shrublands biome. It is found along the Pacific Coast, from as far south as Los Angeles in Southern California up into southern Oregon.
Shrub-steppe is a type of low rainfall natural grassland. While arid, shrub-steppes have sufficient moisture to support a cover of perennial grasses and/or shrubs, a feature which distinguishes them from deserts.
The Puna grassland ecoregion, of the montane grasslands and shrublands biome, is found in the central Andes Mountains of South America. It is considered one of the eight Natural Regions in Peru, but extends south, across Bolivia, as far as northern Argentina and Chile. The term puna encompasses diverse ecosystems of the high Central Andes above 3200–3400 m.
The Mongolian-Manchurian grassland ecoregion, also known as the Mongolian-Manchurian steppe, in the temperate grassland Biome, is found in Mongolia, the Chinese Autonomous region of Inner Mongolia and northeastern China.
The Wyoming Basin shrub steppe ecoregion, within the deserts and xeric shrublands biome, is a shrub steppe in the northwestern United States.
Montane ecosystems refers to any ecosystem found in mountains. These ecosystems are strongly affected by climate, which gets colder as elevation increases. They are stratified according to elevation. Dense forests are common at moderate elevations. However, as the elevation increases, the climate becomes harsher, and the plant community transitions to grasslands or tundra.
The ecology of the Great Plains is diverse, largely owing to their great size. Differences in rainfall, elevation, and latitude create a variety of habitats including short grass, mixed grass, and tall-grass prairies, and riparian ecosystems.
The Central Great Plains are a semi-arid prairie ecoregion of the central United States, part of North American Great Plains. The region runs from west-central Texas through west-central Oklahoma, central Kansas, and south-central Nebraska.
The Patagonian grasslands (NT0804) is an ecoregion in the south of Chile, Argentina and the Falkland Islands. The grasslands are home to diverse fauna, including several rare or endemic species of birds. There are few protected areas. The grasslands are threatened by overgrazing by sheep, which supply high-quality merino wool. Efforts are being made to develop sustainable grazing practices to avoid desertification.
The Sayan intermontane steppe ecoregion is sometimes referred to as a "steppe island", being an expanse of grassland and shrubs surrounded by mountain forests in the Tyva Republic of south central Siberia, Russia. The Altai mountains are to the west, the Sayan mountains to the north, and the Tannu-Ola mountains to the south. The ecoregion is in the Temperate grasslands, savannas, and shrublands biome, and the Palearctic ecozone, with a Humid Continental climate. For much of its length, it follows the course of the upper Yenisei River. It covers 33,928 km2 (13,100 sq mi).