Grassland

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.

Chile (3), Patagonia, Road Y-50 towards Rio Verde
Grassland in Magallanes Region, Patagonia, Chile
Sanilfefonso22jf
A grassland in the Philippines

Vegetation

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.

Konza1
The Konza tallgrass prairie in the Flint Hills of northeastern Kansas

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.[1]

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).[2] The root systems of perennial grasses and forbs form complex mats that hold the soil in place.

Evolution

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.[3]

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.[1]

Climates

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.[4] 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.

Biodiversity and conservation

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. 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.

Human impact and economic importance

Prau
Grassland in Cantabria, northern Spain
Morton Arboretum grassland
A restored grassland ecosystem at Morton Arboretum in Illinois

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.

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.

Types of grassland

Schimper (1898)

Grassland types by Schimper (1898, 1903):[5]

  • meadow (hygrophilous or tropophilous grassland)
  • steppe (xerophilous grassland)
  • savannah (xerophilous grassland containing isolated trees)

Ellenberg and Mueller-Dombois (1967)

Grassland types by Ellenberg and Mueller-Dombois (1967):[6]

Formation-class V. Terrestrial herbaceous communities

  1. Savannas and related grasslands (tropical or subtropical grasslands and parklands)
  2. Steppes and related grasslands (e.g. North American "prairies" etc.)
  3. Meadows, pastures or related grasslands
  4. Sedge swamps and flushes
  5. Herbaceous and half-woody salt swamps
  6. Forb vegetation

Laycock (1979)

Grassland types by Laycock (1979):[7]

  1. tallgrass (true) prairie;
  2. shortgrass prairie;
  3. mixed-grass prairie;
  4. shrub steppe;
  5. annual grassland;
  6. desert (arid) grassland;
  7. high mountain grassland.

Other

Tropical and subtropical

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.

Temperate

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.

Negri-Nepote Temperate Grasslands in New Jersey
Negri-Nepote temperate grasslands in New Jersey

Flooded

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.

Montane

AntelopeValleyCAgrassland
Grassland in the Antelope Valley, California

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.

Tundra grasslands

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.

Desert and xeric

Also called desert grasslands, this is composed of sparse grassland ecoregions located in the deserts and xeric shrublands biome.

Animals

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.[8]

There is evidence for grassland being much the product of animal behaviour and movement;[9] 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.

Temperate grasslands, savannas, and shrublands ecoregions

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
Argentine Espinal Argentina
Argentine Monte Argentina
Humid Pampas Argentina
Patagonian grasslands Argentina, Chile
Patagonian steppe Argentina, Chile
Semi-arid Pampas Argentina
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
Kazakh Uplands Kazakhstan
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

Tropical and subtropical grasslands, savannas, and shrublands ecoregions

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
Aripo Savannas Trinidad
Beni savanna Bolivia
Campos rupestres Brazil
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

References

  1. ^ a b "University of California Museum of Paleontology Grasslands website". Ucmp.berkeley.edu. Retrieved 2011-12-01.
  2. ^ "NASA Earth Observatory webpage". Earthobservatory.nasa.gov. Retrieved 2011-12-01.
  3. ^ Piperno, D. R.; Sues, HD (2005). "Dinosaurs Dined on Grass". Science. 310 (5751): 1126–8. doi:10.1126/science.1121020. PMID 16293745.
  4. ^ "EO Experiments: Grassland Biome". Earthobservatory.nasa.gov. Retrieved 2011-12-01.
  5. ^ Schimper, A. F. W. 1898. Pflanzen-Geographie auf physiologischer Grundlage. Fisher, Jena. 876 pp. English translation, 1903.
  6. ^ Ellenberg, H. & D. Mueller-Dombois. 1967. Tentative physiognomic-ecological classification of plant formations of the Earth [based on a discussion draft of the UNESCO working group on vegetation classification and mapping.] Berichte des Geobotanischen Institutes der Eidg. Techn. Hochschule, Stiftung Rübel, Zürich 37 (1965-1966): 21—55, [1].
  7. ^ Laycock, W.A. 1979. Introduction, pp. 1-2, in: French. N R. (ed.). Perspectives in Grassland Ecology. Springer, New York, 204 pp., [2].
  8. ^ "University of California – Santa Barbara Temperate Grasslands website". Kids.nceas.ucsb.edu. Retrieved 2011-12-01.
  9. ^ "How can grazing heal land?". ManagingWholes.com. Retrieved 2011-12-01.

Further reading

  • Courtwright, Julie. 2011. Prairie Fire: A Great Plains History. University Press of Kansas. 274 pp.
  • French, N. R. (ed.). 1979. Perspectives in Grassland Ecology. Springer, New York, 204 pp., [3].
  • Suttie, J. M.; Reynolds, S. G.; C. Batello. 2005. Grasslands of the world. Rome: FAO. [4].
Butte Valley National Grassland

Butte Valley National Grassland is a 18,425-acre (7,456 ha) United States National Grassland located in northern California. Administered by the United States Forest Service, it is located in northern Siskiyou County, near the Oregon border, between the communities of Dorris and Macdoel along U.S. Highway 97. It was dedicated in July 1991 as the nation's 20th National Grassland. It is administered as part of the Klamath National Forest, and is the sole National Grassland in California and in Region 5 (Pacific Southwest) of the Forest Service. Administrative offices are located in Macdoel, California.

Calcareous grassland

Calcareous grassland (or alkaline 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.

There are large areas of calcareous grassland in northwestern Europe, particularly areas of southern England, such as Salisbury Plain and the North and South Downs.

The machair forms a different kind of calcareous grassland, where fertile low-lying plains are formed on ground that is calcium-rich due to shell sand (pulverised sea shells).

Comanche National Grassland

Comanche National Grassland is a National Grassland located in southeastern Colorado, United States. It is the sister grassland of Cimarron National Grassland and contains both prairie grasslands and canyons. It is separated into two sections, each operated by a local ranger district, one of which is in Springfield and the other of which is in La Junta. The grassland is administered by the Forest Service together with the Pike and San Isabel National Forests, and the Cimarron National Grassland, from common headquarters located in Pueblo, Colorado.

Crooked River National Grassland

Crooked River National Grassland is a National Grassland located in Jefferson County in the north-central part of the U.S. state of Oregon. It has a land area of 173,629 acres (70,265 ha). It contains two National Wild and Scenic Rivers, the Deschutes River and the Crooked River. The grassland is managed together with the Ochoco National Forest from Forest Service offices in Prineville. There are local ranger district offices located in Madras, its nearest city.

Flooded grasslands and savannas

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. Large congregations of migratory and resident waterbirds may be found in these regions. However, the relative importance of these habitat types for these birds as well as more vagile taxa typically varies as the availability of water and productivity annually and seasonally shifts among complexes of smaller and larger wetlands throughout a region.This habitat type is found on four of the continents on Earth. Some globally outstanding flooded savannas and grasslands occur in the Everglades, Pantanal, Sahelian flooded savannas, Zambezian flooded savannas, and the Sudd. The Everglades are the world’s largest rain-fed flooded grassland on a limestone substrate, and feature some 11,000 species of seed-bearing plants, 25 varieties of orchids, 300 bird species, and 150 fish species. The Pantanal, one of the largest continental wetlands on Earth, supports over 260 species of fish, 700 birds, 90 mammals, 160 reptiles, 45 amphibians, 1,000 butterflies, and 1,600 species of plants. The flooded savannas and grasslands are generally the largest complexes in each region.

Grassland, Alberta

Grassland is a hamlet in northern Alberta in Athabasca County, located on Highway 63, 151 kilometres (94 mi) northeast of Edmonton.

Lyndon B. Johnson National Grassland

Lyndon B. Johnson (LBJ) National Grassland is a National Grassland located in the Great Plains of the northern part of the U.S. state of Texas near Decatur and within an hour's drive from Fort Worth. It is primarily used for recreation such as hiking, camping, horseback riding, fishing and hunting. It is also used as grazing land for cattle and other livestock.

Camping and other activities are free of charge, and visitors may camp in virtually any area of the park. Both pull-through and hike-in campsites are available. Some areas require a small fee for use, but these are few and clearly marked.

It is located primarily in the northern part of Wise County, but a small portion extends northward into southern Montague County. It has a land area of 20,309 acres (8,219 ha). The grassland is administered together with all four United States National Forests and two National Grasslands located entirely in Texas, from common offices in Lufkin, Texas. The units include Angelina, Davy Crockett, Sabine, and Sam Houston National Forests, plus Caddo National Grassland and Lyndon B. Johnson. There are local ranger district offices located in Decatur.

Medicine Bow – Routt National Forest

Medicine Bow – Routt National Forest is the official title to a U.S. Forest Service managed area extending over 2,222,313 acres (8,993.38 km2) in the states of Wyoming and Colorado, United States. What were once three separate areas, Medicine Bow National Forest, Routt National Forest and Thunder Basin National Grassland were administratively combined in 1995 due to similarity of the resources, proximity to each other and for administrative purposes.

The Medicine Bow National Forest section (1,096,891 acres) is located in southeastern Wyoming and was originally created as a forest reserve in 1902. Named after the Native American powwows in which numerous tribes would congregate here in search of mountain mahogany, which was an excellent wood for the manufacturing of bows, and to perform rituals hoped to cure diseases and thus make "good medicine". Areas of interest include the Snowy Range where the highest peak is Medicine Bow Peak at 12,013 feet (3,662 m) and is visible from Snowy Range Pass, 10,847 ft (3,306 m), on Wyoming highway 130. The Encampment River, Huston Park, Savage Run and Platte River Wildernesses are all located within the Medicine Bow portion of the National Forest. (A small part of the Platte River Wilderness extending into Colorado is shared with Routt National Forest, as indicated below.) Vedauwoo is located immediately north of Interstate 80 and consists of numerous rock outcroppings popular with rock climbers. In descending order of land area the forest is located in Carbon, Albany, Converse, Natrona, and Platte counties. There are local ranger district offices located in Laramie, Saratoga, and Douglas.Routt National Forest lands (1,125,438 acres) are located in northwestern Colorado. The Steamboat Ski Resort is located in the forest, on Mount Werner. The forest is named after John Routt, the first Governor of Colorado. It was established in 1905 by President Theodore Roosevelt. The forest encompasses 1,126,346 acres (4,558.16 km2). The Continental Divide splits the forest in half, with the east part drained by the North Platte River and the west drained by the Yampa River. Routt National Forest contains seven wilderness areas entirely or partially within it. Entirely within Routt are the Mount Zirkel and the Sarvis Creek Wildernesses. Lying mostly within neighboring forests but extending into Routt are the Flat Tops (White River NF 83.5%), Neota (Roosevelt NF 97.3%), Never Summer (Arapaho NF 68.4%), Platte River (Medicine Bow NF 96.8%), and Rawah (Roosevelt NF 98.0%) Wildernesses. In descending order of land area the forest is located in Routt, Jackson, Rio Blanco, Grand, Moffat, and Garfield counties. There are local ranger district offices located in Steamboat Springs, Walden, and Yampa.

Thunder Basin National Grassland (547,620 acres) is located in northeastern Wyoming and consists primarily of lands leased to cattle interests. In descending order of land area the grassland is located in Weston, Converse, Campbell, Niobrara, and Crook counties. There are local ranger district offices located in Douglas.

The forest headquarters is in Laramie, Wyoming.

Mongolian-Manchurian grassland

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.

Montane grasslands and shrublands

Montane grasslands and shrublands is a habitat type defined by the World Wildlife Fund. The biome includes high altitude grasslands and shrublands around the world. The term "montane" in the name of the biome refers to "high altitude", rather than the ecological term which denotes the region below treeline.

This habitat type includes high elevation (montane and alpine) grasslands and shrublands, including the puna and paramo in South America, subalpine heath in New Guinea and East Africa, steppes of the Tibetan plateaus, as well as other similar subalpine habitats around the world.The plants and animals of tropical montane paramos display striking adaptations to cool, wet conditions and intense sunlight. Around the world, characteristic plants of these habitats display features such as rosette structures, waxy surfaces, and abundant pilosity.The paramos of the northern Andes are the most extensive examples of this habitat type. Although ecoregion biotas are most diverse in the Andes, these ecosystems are distinctive wherever they occur in the tropics. The heathlands and moorlands of East Africa (e.g., Mount Kilimanjaro, Mount Kenya, Rwenzori Mountains), Mount Kinabalu of Borneo, and the Central Range of New Guinea are all limited in extent, isolated, and support endemic plants and animals.Drier subtropical montane grasslands, savannas, and woodlands include the Ethiopian Highlands, the Zambezian montane grasslands and woodlands, and the montane habitats of southeastern Africa.The montane grasslands of the Tibetan Plateau still support relatively intact migrations of Tibetan antelope (Pantholops hodgsoni) and kiang, or Tibetan wild ass (Equus hemionus). A unique feature of many tropical paramos is the presence of giant rosette plants from a variety of plant families, such as Lobelia (Africa), Puya (South America), Cyathea (New Guinea), and Argyroxiphium (Hawai’i). These plant forms can reach elevations of 4,500–4,600 metres (14,800–15,100 ft) above sea level.

Pampas

The Pampas (from the Quechua: pampa, meaning "plain") are fertile South American lowlands that cover more than 750,000 km2 (289,577 sq mi) and include the Argentine provinces of Buenos Aires, La Pampa, Santa Fe, Entre Ríos and Córdoba; all of Uruguay; and the southernmost Brazilian State, Rio Grande do Sul. The vast plains are a natural region, interrupted only by the low Ventana and Tandil hills, near Bahía Blanca and Tandil (Argentina), with a height of 1,300 m (4,265 ft) and 500 m (1,640 ft), respectively.

The climate is temperate, with precipitation of 600 to 1,200 mm (23.6 to 47.2 in) that is more or less evenly distributed through the year, making the soils appropriate for agriculture. The area is also one of the distinct physiography provinces of the larger Paraná-Paraguay Plain division.

Pawnee National Grassland

Pawnee National Grassland is a United States National Grassland located in northeastern Colorado on the Colorado Eastern Plains. The grassland is located in the South Platte River basin in remote northern and extreme northeastern Weld County between Greeley and Sterling. It comprises two parcels totaling 193,060 acres (78,130 ha) largely between State Highway 14 and the Wyoming border. The larger eastern parcel lies adjacent to the borders of both Nebraska and Wyoming. It is administered in conjunction with the Arapaho-Roosevelt National Forest from the U.S. Forest Service office in Fort Collins, Colorado, with a local ranger district office in Greeley.The grassland is in an especially depopulated area of the Great Plains. It saw limited cultivation in the early 20th century but was withdrawn from farming after the Dust Bowl. The communities of Keota and Purcell are located within the grassland. The town of Grover is located directly between the two large parcels of the grasslands near the Crow Creek. Briggsdale sits at the southern end where State Highway 14 and State Highway 392 meet. State Highway 71 traverses the eastern unit north of Stoneham. The eastern unit is drained by Pawnee Creek, a tributary of the South Platte. The western unit is largely drained by Crow Creek.

Camping is available at the Crow Valley Recreation Area northwest of Briggsdale. The grassland contains several hiking trails, including one that allows foot access to the Pawnee Buttes, the most notable geologic feature of the grasslands. Bird watching is a popular recreational activity for day hikers, especially at the Chalk Bluffs, a raptor nesting site.

Recreational activities on the Pawnee Grasslands have been somewhat curtailed over the last 10 years due to the discovery of extractable oil and natural gas. According to the US Forest Service there are 63 active vertical oil and natural gas wells, and less than 3,000 acres from the 193,060 acres is protected from drilling.

Rita Blanca National Grassland

Rita Blanca National Grassland is a National Grassland on the Great Plains near the community of Texline in northwest Dallam County, Texas, in the Texas Panhandle, and in southern Cimarron County, Oklahoma, in the western Oklahoma Panhandle. The principal city in the area is Dalhart, Texas, which houses the XIT Museum.

The name Rita Blanca (Little White River) was applied to a stream by Spanish sheepherders in the 19th Century. It was later used by the XIT ranch and has been applied to other geographic features in the vicinity.

Salisbury Plain

Salisbury Plain is a chalk plateau in the south western part of central southern England covering 300 square miles (780 km2). It is part of a system of chalk downlands throughout eastern and southern England formed by the rocks of the Chalk Group and largely lies within the county of Wiltshire, but also stretching into Berkshire and Hampshire. The plain is famous for its rich archaeology, including Stonehenge, one of England's best known landmarks. Largely as a result of the establishment of the Defence Training Estate Salisbury Plain (DTE SP), the plain is sparsely populated and is the largest remaining area of calcareous grassland in north-west Europe. Additionally the plain has arable land, and a few small areas of beech trees and coniferous woodland. Its highest point is Easton Hill.

South Downs

The South Downs are a range of chalk hills that extends for about 260 square miles (670 km2) across the south-eastern coastal counties of England from the Itchen Valley of Hampshire in the west to Beachy Head, in the Eastbourne Downland Estate, East Sussex, in the east. The Downs are bounded on the northern side by a steep escarpment, from whose crest there are extensive views northwards across the Weald. The South Downs National Park forms a much larger area than the chalk range of the South Downs and includes large parts of the Weald.

The South Downs are characterised by rolling chalk downland with close-cropped turf and dry valleys, and are recognised as one of the most important chalk landscapes in England. The range is one of the four main areas of chalk downland in southern England.The South Downs are relatively less populated compared to South East England as a whole, although there has been large-scale urban encroachment onto the chalk downland by major seaside resorts, including most notably Brighton and Hove. The South Downs have been inhabited since ancient times and at periods the area has supported a large population, particularly during Romano-British times. There is a rich heritage of historical features and archaeological remains, including defensive sites, burial mounds and field boundaries. Within the South Downs Environmentally Sensitive Area there are thirty-seven Sites of Special Scientific Interest, including large areas of chalk grassland.The grazing of sheep on the thin, well-drained chalk soils of the Downs over many centuries and browsing by rabbits resulted in the fine, short, springy turf, known as old chalk grassland, that has come to epitomise the South Downs today. Until the middle of the 20th century, an agricultural system operated by downland farmers known as 'sheep-and-corn farming' underpinned this: the sheep (most famously the Southdown breed) of villagers would be systematically confined to certain corn fields to improve their fertility with their droppings and then they would be let out onto the downland to graze. However, starting in 1940 with government measures during World War II to increase domestic food production and continuing into the 1950s, much grassland was ploughed up for arable farming, fundamentally changing the landscape and ecology, with the loss of much biodiversity. As a result, while old chalk grassland accounted for 40-50% of the eastern Downs before the war, only 3-4% survives. This and development pressures from the surrounding population centres ultimately led to the decision to create the South Downs National Park, which came into full operation on 1 April 2011, to protect and restore the Downs.

The South Downs have also been designated as a National Character Area (NCA 125) by Natural England. It is bordered by the Hampshire Downs, the Wealden Greensand, the Low Weald and the Pevensey Levels to the north and the South Hampshire Lowlands and South Coast Plain to the south.The downland is a highly popular recreational destination, particularly for walkers, horseriders and mountain bikers. A long distance footpath and bridleway, the South Downs Way, follows the entire length of the chalk ridge from Winchester to Eastbourne, complemented by many interconnecting public footpaths and bridleways.

Temperate grasslands, savannas, and shrublands

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 habitat type is known as prairie in North America, pampas in South America, veld in Southern Africa and steppe in Asia. Generally speaking, these regions are devoid of trees, except for riparian or gallery forests associated with streams and rivers.Steppes/shortgrass prairies are short grasslands that occur in semi-arid climates. Tallgrass prairies are tall grasslands in areas of higher rainfall. Heaths and pastures are, respectively, low shrublands and grasslands where forest growth is hindered by human activity but not the climate.

Tall grasslands, including the tallgrass prairie of North America, the north-western parts of Eurasian steppe (Ukraine and south of Russia) and the Humid Pampas of Argentina, have moderate rainfall and rich soils which make them ideally suited to extensive agriculture, and tall grassland ecoregions include some of the most productive grain-growing regions in the world. The expanses of grass in North America and Eurasia once sustained migrations of large vertebrates such as buffalo (Bubalus bubalis), saiga (Saiga tatarica), and Tibetan antelopes (Pantholops hodgsoni) and kiang (Equus hemionus). Such phenomena now occur only in isolated pockets, primarily in the Daurian Steppe and Tibetan Plateau.The floral communities of the Eurasian steppes and the North American Great Plains, have been largely extirpated through conversion to agriculture. Nonetheless, as many as 300 different plant species may grow on less than 3 acres of North American tallgrass prairie, which also may support more than 3 million individual insects per acre. The Patagonian Steppe and Grasslands are notable for distinctiveness at the generic and familial level in a variety of taxa.

Tropical and subtropical grasslands, savannas, and shrublands

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.

Tundra

In physical geography, tundra () is a type of biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра (tûndra) from the Kildin Sami word тӯндар (tūndâr) meaning "uplands", "treeless mountain tract". Tundra vegetation is composed of dwarf shrubs, sedges and grasses, mosses, and lichens. Scattered trees grow in some tundra regions. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or timberline.

There are three regions and associated types of tundra: Arctic tundra, alpine tundra, and Antarctic tundra.

United States National Grassland

National Grassland is a classification of protected and managed federal lands in the United States authorized by Title III of the Bankhead–Jones Farm Tenant Act of 1937. For administrative purposes, they are essentially identical to United States National Forests, except that grasslands are areas primarily consisting of prairie. Like National Forests, National Grasslands may be open for hunting, grazing, mineral extraction, recreation and other uses. Various National Grasslands are typically administered in conjunction with nearby National Forests.

All but three National Grasslands are on or at the edge of the Great Plains. Those three are in southeastern Idaho, northeastern California, and central Oregon. The three National Grasslands in North Dakota, together with one in northwestern South Dakota, are administered jointly as the Dakota Prairie Grasslands. National Grasslands are generally much smaller than National Forests. Whereas a typical National Forest would be about 1,000,000 acres (400,000 ha), the average Grassland size is 191,914 acres (77,665 ha). The largest National Grassland, the Little Missouri National Grassland in North Dakota, covers 1,028,784 acres (416,334 ha), which is approximately the median size of a National Forest. As of September 30, 2007, the total area of all 20 National Grasslands was 3,838,280 acres (1,553,300 ha).

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