Fellfield

Last updated March 31, 2019

A fellfield or fell field comprises the environment of a slope, usually alpine or tundra, where the dynamics of frost (freeze and thaw cycles) and of wind give rise to characteristic plant forms in scree interstices.^[1]

Alpine climate is the average weather (climate) for the regions above the tree line. This climate is also referred to as a mountain climate or highland climate.

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 from the Kildin Sami word тӯндар 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 between the tundra and the forest is known as the tree line or timberline.

Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor to ice as the water vapor reaches the freezing point. In temperate climates, it most commonly appears on surfaces near the ground as fragile white crystals; in cold climates, it occurs in a greater variety of forms. The propagation of crystal formation occurs by the process of nucleation.

Soil dynamics

The freeze-thaw cycles tend to push plants out of the soil. In addition, the high porosity of the soil makes a fellfield a difficult place for plants to grow.^[1] Fellfields often have typical patterns of rocks: lines of rocks that have been pushed out of the soil, and slid into a low region.^[2]

Porosity or void fraction is a measure of the void spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure the "accessible void", the total amount of void space accessible from the surface. There are many ways to test porosity in a substance or part, such as industrial CT scanning. The term porosity is used in multiple fields including pharmaceutics, ceramics, metallurgy, materials, manufacturing, hydrology, earth sciences, soil mechanics and engineering.

Botany

In botany the term "fellfield" describes an ecoregion, ecosystem, habitat, or plant community. The term frequently used is alpine fellfield. Fellfield is usually applied to an alpine tundra region of high altitude mountains, or high latitude islands, and the alpine plants there.^[2]

Botany, also called plant science(s), plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek word βοτάνη (botanē) meaning "pasture", "grass", or "fodder"; βοτάνη is in turn derived from βόσκειν (boskein), "to feed" or "to graze". Traditionally, botany has also included the study of fungi and algae by mycologists and phycologists respectively, with the study of these three groups of organisms remaining within the sphere of interest of the International Botanical Congress. Nowadays, botanists study approximately 410,000 species of land plants of which some 391,000 species are vascular plants, and approximately 20,000 are bryophytes.

An ecoregion is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than an ecozone. All three of these are either less or greater than an ecosystem. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural communities and species. The biodiversity of flora, fauna and ecosystems that characterise an ecoregion tends to be distinct from that of other ecoregions. In theory, biodiversity or conservation ecoregions are relatively large areas of land or water where the probability of encountering different species and communities at any given point remains relatively constant, within an acceptable range of variation.

An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the system through photosynthesis and is incorporated into plant tissue. By feeding on plants and on one-another, animals play an important role in the movement of matter and energy through the system. They also influence the quantity of plant and microbial biomass present. By breaking down dead organic matter, decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and other microbes.

Flora

Fellfields are typically populated by cushion plants: perennials that grow close to the ground. Cushion plants are well-adapted to the dryness and short growing season of a fellfield. Cushion plants often have hairy foliage and long taproots, to gather and retain moisture. Examples of cushion plants include the lupines and buckwheats.^[2]

A cushion plant is a compact, low growing, mat forming plant that is found in alpine, subalpine, arctic, or subarctic environments around the world. The term "cushion" is usually applied to woody plants that grow as spreading mats, are limited in height above the ground, have relatively large and deep tap roots, and have life histories adapted to slow growth in a nutrient poor environment with delayed reproductivity and reproductive cycle adaptations. The plant form is an example of parallel or convergent evolution with species from many different plant families on different continents converging on the same evolutionary adaptations to endure the harsh environmental conditions.

A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward. In some plants, such as the carrot, the taproot is a storage organ so well developed that it has been cultivated as a vegetable.

Buckwheat, or common buckwheat, is a plant cultivated for its grain-like seeds and as a cover crop. A related and more bitter species, Fagopyrum tataricum, is a domesticated food plant common in Asia and Central and Eastern Europe. Despite the name, buckwheat is not related to wheat, as it is not a grass. Instead, buckwheat is related to sorrel, knotweed, and rhubarb. Because its seeds are rich in complex carbohydrates, it is referred to as a pseudocereal.

Fellfield species

Alpine flora list

Azorella selago is a species of cushion plant native to the sub-Antarctic islands of the Southern Ocean, including the Crozet Islands, the Possession Islands, the Heard Island and McDonald Islands, the Kerguelen Islands, and the Prince Edward Islands. The closely related Azorella macquariensis, which is endemic to Macquarie Island, was split from it taxonomically in 1989. A. selago is often a keystone species where it occurs and is well studied for its contribution to its native ecosystems.

Oenothera xylocarpa is a species of flowering plant in the evening primrose family known by the common name woodyfruit evening primrose. It is native to the Sierra Nevada of California, its range extending just into western Nevada. It grows in coniferous forest and meadow habitat, often in soils rich in pumice and other gravel. It is a perennial herb growing from a thick taproot and producing a flat, dense rosette of hairy, gray-green leaves. There is no stem. The showy flowers appear amidst the leaves. Each has four petals which may be nearly 4 centimeters long, bright yellow in color, fading pink to red with age. The fruit is a straight, curving, or twisting capsule which may be up to 9 centimeters long.

Some geologists find it is controversial to share the term for biology and geomorphology applications.^[2]

Related Research Articles

Taiga, also known as boreal forest or snow forest, is a biome characterized by coniferous forests consisting mostly of pines, spruces, and larches.

Weathering Breaking down of rocks, soil and minerals as well as artificial materials through contact with the Earths atmosphere, biota and waters

Weathering is the breaking down of rocks, soil, and minerals as well as wood and artificial materials through contact with the Earth's atmosphere, water, and biological organisms. Weathering occurs in situ, that is, in the same place, with little or no movement, and thus should not be confused with erosion, which involves the movement of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity and then being transported and deposited in other locations.

In geology, permafrost is ground, including rock or (cryotic) soil, at or below the freezing point of water 0 °C (32 °F) for two or more years. Most permafrost is located in high latitudes, but at lower latitudes alpine permafrost occurs at higher elevations. Ground ice is not always present, as may be in the case of non-porous bedrock, but it frequently occurs and it may be in amounts exceeding the potential hydraulic saturation of the ground material. Permafrost accounts for 0.022% of total water on Earth and the permafrost region covers 24% of exposed land in the Northern Hemisphere. It also occurs subsea on the continental shelves of the continents surrounding the Arctic Ocean, portions of which were exposed during the last glacial period.

Alpine tundra is a type of natural region or biome that does not contain trees because it is at high elevation. As the latitude of a location approaches the poles, the threshold elevation for alpine tundra gets lower until it reaches sea level, and alpine tundra merges with polar tundra.

The tree line is the edge of the habitat at which trees are capable of growing. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions. The tree line is sometimes distinguished from a lower timberline or forest line, which is the line below which trees form a forest with a closed canopy.

Scree is a collection of broken rock fragments at the base of crags, mountain cliffs, volcanoes or valley shoulders that has accumulated through periodic rockfall from adjacent cliff faces. Landforms associated with these materials are often called talus deposits. Talus deposits typically have a concave upwards form, while the maximum inclination corresponds to the angle of repose of the mean debris size.

Alpine plants are plants that grow in an alpine climate, which occurs at high elevation and above the tree line. There are many different plant species and taxon that grow as a plant community in these alpine tundra. These include perennial grasses, sedges, forbs, cushion plants, mosses, and lichens. Alpine plants are adapted to the harsh conditions of the alpine environment, which include low temperatures, dryness, ultraviolet radiation, and a short growing season.

Silene acaulis, known as moss campion or cushion pink, is a small mountain-dwelling wildflower that is common all over the high arctic and tundra in the higher mountains of Eurasia and North America,. It is an evergreen perennial.

Páramo high-altitude wet tundra in South America

Páramo can refer to a variety of alpine tundra ecosystems. Some ecologists describe the páramo broadly as "all high, tropical, montane vegetation above the continuous timberline". A more narrow term classifies the páramo according to its regional placement in the northern Andes of South America and adjacent southern Central America. The páramo is the ecosystem of the regions above the continuous forest line, yet below the permanent snowline. It is a "Neotropical high mountain biome with a vegetation composed mainly of giant rosette plants, shrubs and grasses". According to scientists, páramos may be "evolutionary hot spots" and among the fastest evolving regions on Earth.

Bear Rocks are a widely recognized symbol of West Virginia wilderness and among the most frequently photographed places in the state. They are a well-known landmark on the eastern edge of the plateau that includes the Dolly Sods Wilderness. They sit in a high-elevation heathland punctuated with wind-carved sandstone outcrops and is home to more than a dozen rare plant and animal species. Situated on the crest of the Allegheny Front, Bear Rocks afford vistas over the South Branch Potomac River. Visibility can extend eastward to the Shenandoah National Park in Virginia.

Needle ice is a phenomenon that occurs when the temperature of the soil is above 0 °C (32 °F) and the surface temperature of the air is below 0 °C (32 °F). The subterranean liquid water is brought to the surface via capillary action, where it freezes and contributes to a growing needle-like ice column.

Feldmark, also spelt fjaeldmark, is a plant community characteristic of sites where plant growth is severely restricted by extremes of cold and exposure to wind, typical of alpine tundra and subantarctic environments.

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.

Saxifraga bryoides is a species of saxifrage known by the common name of mossy saxifrage. In German it is known as Moosartiger Steinbrech. It is an inhabitant of the Arctic tundra but it also grows in the Alps and other European mountain ranges at high altitudes.

Draba exunguiculata is a species of flowering plant in the mustard family known by the common names clawless draba and Grays Peak draba. It is endemic to Colorado in the United States.

Alpine vegetation refers to the zone of vegetation between the altitudinal limit for tree growth and the nival zone. Alpine zones in Tasmania can be difficult to classify owing to Tasmania's maritime climate limiting snow lie to short periods and the presence of a tree line that is not clearly defined.

The flora of the U.S. Sierra Nevada alpine zone is characterized by small, low growing, cushion and mat forming plants that can survive the harsh conditions in the high-altitude alpine zone above the timber line. These flora often occur in alpine fell-fields. The Sierra Nevada alpine zone lacks a dominant plant species that characterizes it, so may or may not be called a vegetation type. But it is found above the subalpine forest, which is the highest in a succession of recognized vegetation types at increasing elevations.

Raoulia eximia is a species of plant in the aster family. It was first formally described in 1864 by Joseph Dalton Hooker. It is endemic to New Zealand. The plant is commonly known by its Māori name tutāhuna and as the true vegetable sheep, suggesting its appearance at a distance resembling a sheep.

References

1 2 "Peter le Roux". Archived from the original on 2007-08-22.
1 2 3 4 Schoenherr, Allan A. (1992). A Natural History of California . University of California. ISBN 0-520-06922-6.

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[leroux-1] 1 2 "Peter le Roux". Archived from the original on 2007-08-22.

[schoenherr-2] 1 2 3 4 Schoenherr, Allan A. (1992). A Natural History of California . University of California. ISBN 0-520-06922-6.