In physical geography, tundra (/ˈtʌndrə, ˈtʊn-/) 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 (tundra) from the Kildin Sámi word тӯндар (tūndâr) meaning "uplands", "treeless mountain tract". Tundra vegetation is composed of dwarf shrubs, sedges, 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. The tundra soil is rich in nitrogen and phosphorus.
There are three regions and associated types of tundra: Arctic tundra, alpine tundra, and Antarctic tundra.
Arctic tundra occurs in the far Northern Hemisphere, north of the taiga belt. The word "tundra" usually refers only to the areas where the subsoil is permafrost, or permanently frozen soil. (It may also refer to the treeless plain in general, so that northern Sápmi would be included.) Permafrost tundra includes vast areas of northern Russia and Canada. The polar tundra is home to several peoples who are mostly nomadic reindeer herders, such as the Nganasan and Nenets in the permafrost area (and the Sami in Sápmi).
Arctic tundra contains areas of stark landscape and is frozen for much of the year. The soil there is frozen from 25 to 90 cm (10 to 35 in) down, making it impossible for trees to grow. Instead, bare and sometimes rocky land can only support certain kinds of Arctic vegetation, low growing plants such as moss, heath (Ericaceae varieties such as crowberry and black bearberry), and lichen.
Antarctic tundra occurs on Antarctica and on several Antarctic and subantarctic islands, including South Georgia and the South Sandwich Islands and the Kerguelen Islands. Most of Antarctica is too cold and dry to support vegetation, and most of the continent is covered by ice fields. However, some portions of the continent, particularly the Antarctic Peninsula, have areas of rocky soil that support plant life. The flora presently consists of around 300–400 lichens, 100 mosses, 25 liverworts, and around 700 terrestrial and aquatic algae species, which live on the areas of exposed rock and soil around the shore of the continent. Antarctica's two flowering plant species, the Antarctic hair grass (Deschampsia antarctica) and Antarctic pearlwort (Colobanthus quitensis), are found on the northern and western parts of the Antarctic Peninsula. In contrast with the Arctic tundra, the Antarctic tundra lacks a large mammal fauna, mostly due to its physical isolation from the other continents. Sea mammals and sea birds, including seals and penguins, inhabit areas near the shore, and some small mammals, like rabbits and cats, have been introduced by humans to some of the subantarctic islands. The Antipodes Subantarctic Islands tundra ecoregion includes the Bounty Islands, Auckland Islands, Antipodes Islands, the Campbell Island group, and Macquarie Island. Species endemic to this ecoregion include Corybas dienemus and Corybas sulcatus, the only subantarctic orchids; the royal penguin; and the Antipodean albatross.
Alpine tundra does not contain trees because the climate and soils at high altitude block tree growth. The cold climate of the alpine tundra is caused by the low air temperatures, and is similar to polar climate. Alpine tundra is distinguished from arctic tundra in that alpine tundra typically does not have permafrost, and alpine soils are generally better drained than arctic soils. Alpine tundra transitions to subalpine forests below the tree line; stunted forests occurring at the forest-tundra ecotone (the treeline) are known as Krummholz.
Alpine tundra occurs in mountains worldwide. The flora of the alpine tundra is characterized by plants that grow close to the ground, including perennial grasses, sedges, forbs, cushion plants, mosses, and lichens.[18] The flora is adapted to the harsh conditions of the alpine environment, which include low temperatures, dryness, ultraviolet radiation, and a short growing season.
Source: Wikipedia contributors. "Tundra." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 21 May. 2021. Web. 28 Jun. 2021.
Flooded grasslands and savannas is a terrestrial biome 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, Lake Chad flooded savanna, Zambezian flooded grasslands, 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.
Source: Wikipedia contributors. "Flooded grasslands and savannas." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 10 Jun. 2021. Web. 28 Jun. 2021.
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.
Savannas maintain an open canopy despite a high tree density. It is often believed that savannas feature widely spaced, scattered trees. However, in many savannas, tree densities are higher and trees are more regularly spaced than in forests. The South American savanna types cerrado sensu stricto and cerrado dense typically have densities of trees similar to or higher than that found in South American tropical forests, with savanna ranging from 800–3300 trees per hectare (trees/ha) and adjacent forests with 800–2000 trees/ha. Similarly Guinean savanna has 129 trees/ha, compared to 103 for riparian forest, while Eastern Australian sclerophyll forests have average tree densities of approximately 100 per hectare, comparable to savannas in the same region.
Savannas are also characterised by seasonal water availability, with the majority of rainfall confined to one season; they are associated with several types of biomes, and are frequently in a transitional zone between forest and desert or grassland. Savanna covers approximately 20% of the Earth's land area.
Many grassy landscapes and mixed communities of trees, shrubs, and grasses were described as savanna before the middle of the 19th century, when the concept of a tropical savanna climate became established. The Köppen climate classification system was strongly influenced by effects of temperature and precipitation upon tree growth, and his oversimplified assumptions resulted in a tropical savanna classification concept which resulted in it being considered as a "climatic climax" formation. The common usage meaning to describe vegetation now conflicts with a simplified yet widespread climatic concept meaning. The divergence has sometimes caused areas such as extensive savannas north and south of the Congo and Amazon Rivers to be excluded from mapped savanna categories.
"Barrens" has been used almost interchangeably with savanna in different parts of North America. Sometimes midwestern savanna were described as "grassland with trees". Different authors have defined the lower limits of savanna tree coverage as 5–10% and upper limits range as 25–80% of an area.
Two factors common to all savanna environments are rainfall variations from year to year, and dry season wildfires. In the Americas, e.g. in Belize, Central America, savanna vegetation is similar from Mexico to South America and to the Caribbean.
Over many large tropical areas, the dominant biome (forest, savanna or grassland) can not be predicted only by the climate, as historical events plays also a key role, for example, fire activity.[24] In some areas, indeed, it is possible for there to be multiple stable biomes.
Source: Source: Wikipedia contributors. "Savanna." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 20 Jan. 2021. Web. 28 Jun. 2021.
Maquis (French) or macchia (Italian: macchia mediterranea) is a shrubland biome in the Mediterranean region, typically consisting of densely growing evergreen shrubs.
Source: Wikipedia contributors. "Maquis shrubland." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 2 Mar. 2021. Web. 28 Jun. 2021.
Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity. It may be the mature vegetation type in a particular region and remain stable over time, or a transitional community that occurs temporarily as the result of a disturbance, such as fire. A stable state may be maintained by regular natural disturbance such as fire or browsing. Shrubland may be unsuitable for human habitation because of the danger of fire. The term was coined in 1903.
Shrubland species generally show a wide range of adaptations to fire, such as heavy seed production, lignotubers, and fire-induced germination.
In botany and ecology a shrub is defined as a much-branched woody plant less than 8 m high and usually with many stems. Tall shrubs are mostly 2–8 m high, small shrubs 1–2 m high and subshrubs less than 1 m high.
A descriptive system widely adopted in Australia to describe different types of vegetation is based on structural characteristics based on plant life-form, plus the height and foliage cover of the tallest stratum or dominant species.
Source: Wikipedia contributors. "Shrubland." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 9 Jun. 2021. Web. 28 Jun. 2021.
In physical geography, a steppe is an ecoregion characterized by grassland plains without trees apart from those near rivers and lakes. Steppe biomes may include:
- the montane grasslands and shrublands biome
- the temperate grasslands, savannas and shrublands biome
The prairie of North America (especially the shortgrass and mixed prairie) is an example of a steppe, though it is not usually called such. A steppe may be semi-arid or covered with grass or with shrubs or with both, depending on the season and latitude. The term "steppe climate" denotes the climate encountered in regions too dry to support a forest but not dry enough to be a desert. Steppe soils are typically of the chernozem type.
Steppes are usually characterized by a semi-arid or continental climate. Extremes can be recorded in the summer of up to 45 °C (115 °F) and in winter, −55 °C (−65 °F). Besides this major seasonal difference, fluctuations between day and night are also very great. In both the highlands of Mongolia and northern Nevada, 30 °C (85 °F) can be reached during the day with sub-freezing readings at night.
Mid-latitude steppes feature hot summers and cold winters, averaging 250–510 mm (10–20 in) of precipitation per year. Precipitation level alone does not define a steppe climate; potential evapotranspiration also plays a role in the trees origin
The world's largest steppe region, often referred to as "the Great Steppe", is found in Eastern Europe and Central Asia, and neighbouring countries stretching from Ukraine in the west through Russia, Kazakhstan, Turkmenistan and Uzbekistan to the Altai, Koppet Dag and Tian Shan ranges in China.
The inner parts of Anatolia in Turkey, Central Anatolia and East Anatolia in particular and also some parts of Southeast Anatolia, as well as much of Armenia and Iran are largely dominated by cold steppe.
The Pannonian Plain is another steppe region in Central Europe, primarily Hungary.
Another large steppe area (prairie) is located in the central United States, western Canada and northern part of Mexico. The shortgrass prairie steppe is the westernmost part of the Great Plains region. The Columbia Plateau in Southern British Columbia, Oregon, Idaho, and Washington state, is an example of a steppe region in North America outside of the Great Plains.
In South America, cold steppe can be found in Patagonia and much of the high elevation regions east of the southern Andes.
Relatively small steppe areas can be found in the interior of the South Island of New Zealand.
In Europe, some Mediterranean areas have a steppe-like vegetation, such as central Sicily in Italy, southern Portugal, parts of Greece in the southern Athens area, and central-eastern Spain, especially the southeastern coast (around Murcia), and places cut off from adequate moisture due to rain shadow effects such as Zaragoza.
In Asia, a subtropical steppe can be found in semi-arid lands that fringe the Thar Desert of the Indian subcontinent and the Badia of the Arabian peninsula.
In Australia, "subtropical steppe" can be found in a belt surrounding the most severe deserts of the continent and around the Musgrave Ranges.
In North America this environment is typical of transition areas between zones with a Mediterranean climate and true deserts, such as Reno, Nevada, the inner part of California, and much of western Texas and adjacent areas in Mexico.
Source: Wikipedia contributors. "Steppe." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 14 Apr. 2021. Web. 28 Jun. 2021.
A meadow is an open habitat, or field, vegetated by grass, herbs and other non-woody plants. Meadows may be sparsely covered with trees or shrubs, as long as they maintain an open character. They may be naturally occurring or artificially created from cleared shrub or woodland. They can occur naturally under favourable conditions (see perpetual meadows), but they are often maintained by humans for the production of hay, fodder or livestock. Meadow habitats, as a group, are characterized as 'semi-natural grasslands', meaning that they are largely composed of species native to the region, with only limited human intervention.
Meadows attract a multitude of wildlife and support flora and fauna that could not thrive in other habitats. They are ecologically important as they provide areas for animal courtship displays, nesting, food gathering, pollinating insects, and sometimes sheltering, if the vegetation is high enough. There are multiple types of meadows, including agricultural, transitional and perpetual, each playing a unique and important part of the ecosystem.
Like other ecosystems, meadows will experience increased pressure (including on their biodiversity) because of climate change -- especially as precipitation and weather conditions change. However, grasslands and meadows also have an important climate change mitigation potential as carbon sinks; deep rooted grasses store a substantial amount of carbon in soil.
Source: Wikipedia contributors. "Meadow." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 25 Jun. 2021. Web. 28 Jun. 2021.
A discovery by Eva in habitat Agricultural meadow on 04.06.2021. Thomisidae (Thomisidae) is a family of arachnids. Post your nature observations of Animal sightings in the NatureSpots App, too! #NatureSpots #Animal #Agriculturalmeadow
A discovery by Danny VG in habitat Garden on 08.06.2021. Hoplodrina ambigua (Hoplodrina ambigua) is a species of insect. Post your nature observations of Animal sightings in the NatureSpots App, too! #NatureSpots #Animal #Garden
A discovery by Danny VG in habitat Garden on 08.06.2021. Hoplodrina ambigua (Hoplodrina ambigua) is a species of insect. Post your nature observations of Animal sightings in the NatureSpots App, too! #NatureSpots #Animal #Garden
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