Quadrat (Geometrie)
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Quadrat (Geometrie)
A quadrat is a frame used in ecology, geography, and biology to isolate a standard unit of area for study of the distribution of an item over a large area. Quadrats are traditionally square, but modern quadrats can be rectangular, circular, or irregular. A quadrat is suitable for sampling or observing plants, slow-moving animals, and some aquatic organisms. A photo-quadrat is a photographic record of the area framed by a quadrat. It may use a physical frame to indicate the area, or may rely on fixed camera distance and lens field of view to automatically cover the specified area of substrate. Parallel laser pointers mounted on the camera can also be used as scale indicators. The photo is taken perpendicular to the surface, or as close as possible to perpendicular for uneven surfaces. History The systematic use of quadrats was developed by the pioneering plant ecologists R. Pound and F. E. Clements between 1898 and 1900. The method was then swiftly applied for many purposes in e ...
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Quadrat Sample
A quadrat is a frame, traditionally square, used in ecology, geography and biology to isolate a standard unit of area for study of the distribution of an item over a large area. Modern quadrats can for example be rectangular, circular, or irregular. The quadrat is suitable for Sampling (statistics), sampling plants, slow-moving animals, and some aquatic organisms. A photo-quadrat is a photographic record of the area framed by a quadrat. It may use a physical frame to indicate the area, or may rely on fixed camera distance and lens field of view to automatically cover the specified area of substrate. Parallel laser pointers mounted on the camera can also be used as scale indicators. The photo is taken perpendicular to the surface, or as close as possible to perpendicular for uneven surfaces. History The systematic use of quadrats was developed by the pioneering plant ecologists R. Pound and F. E. Clements between 1898 and 1900. The method was then swiftly applied for many purpos ...
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Habitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical manifestation of its ecological niche. Thus "habitat" is a species-specific term, fundamentally different from concepts such as environment or vegetation assemblages, for which the term "habitat-type" is more appropriate. The physical factors may include (for example): soil, moisture, range of temperature, and light intensity. Biotic factors will include the availability of food and the presence or absence of predators. Every species has particular habitat requirements, with habitat generalist species able to thrive in a wide array of environmental conditions while habitat specialist species requiring a very limited set of factors to survive. The habitat of a species is not necessarily found in a geographical area, it can be the interior ...
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Ecology Terminology
Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps with the closely related sciences of biogeography, evolutionary biology, genetics, ethology, and natural history. Ecology is a branch of biology, and it is not synonymous with environmentalism. Among other things, ecology is the study of: * The abundance, biomass, and distribution of organisms in the context of the environment * Life processes, antifragility, interactions, and adaptations * The movement of materials and energy through living communities * The successional development of ecosystems * Cooperation, competition, and predation within and between species * Patterns of biodiversity and its effect on ecosystem processes Ecology has practical applications in conservation biology, wetland management, natural resource management (ag ...
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Stand Level Modelling
A forest stand is a contiguous community of trees sufficiently uniform in composition, structure, age, size, class, distribution, spatial arrangement, site quality, condition, or location to distinguish it from adjacent communities. A forest is a "collection of stands" also utilizing the practices of forestry. Stand level modelling is a type of modelling in the forest sciences in which the main unit is a forested stand. Stand description A forest stand is commonly described as in 10ths or 10%s. Thus a ratio could be given of: 3 Ponderosa pines, 2 mangrove trees, 5 silver spruces. If there was a mixed stand that stand mix could be described as mixed up to 10%, mixed 10–40% and a mixed stand over that amount. The form of mixing of the tree types is commonly given as: * individuals – when there are a few unconnected trees of a type. * troop – up to 5 trees connected of one type. * group – when there are more than 5 trees, but they are shorter than a harvestable tree. * ...
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Differential GPS
Differential Global Positioning Systems (DGPSs) supplement and enhance the positional data available from global navigation satellite systems (GNSSs). A DGPS for GPS can increase accuracy by about a thousandfold, from approximately to . DGPSs consist of networks of fixed position, ground-based reference stations. Each reference station calculates the difference between its highly accurate known position and its less accurate satellite-derived position. The stations broadcast this data locally—typically using ground-based transmitters of shorter range. Non-fixed (mobile) receivers use it to correct their position by the same amount, thereby improving their accuracy. The United States Coast Guard (USCG) and the Canadian Coast Guard (CCG) each run DGPSs in the United States and Canada on longwave radio frequencies between and near major waterways and harbors. The USCG's DGPS was named NDGPS (Nationwide DGPS) and was jointly administered by the Coast Guard and the U.S. Departmen ...
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Theodolite
A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and infrastructure construction, and some specialized applications such as meteorology and rocket launching. It consists of a moveable telescope mounted so it can rotate around horizontal and vertical axes and provide angular readouts. These indicate the orientation of the telescope, and are used to relate the first point sighted through the telescope to subsequent sightings of other points from the same theodolite position. These angles can be measured with accuracies down to microradians or seconds of arc. From these readings a plan can be drawn, or objects can be positioned in accordance with an existing plan. The modern theodolite has evolved into what is known as a total station where angles and distances are measured electronically, and ...
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Total Station
A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for surveying and building construction. It is an electronic transit theodolite integrated with electronic distance measurement (EDM) to measure both vertical and horizontal angles and the slope distance from the instrument to a particular point, and an on-board computer to collect data and perform triangulation calculations. Robotic or motorized total stations allow the operator to control the instrument from a distance via remote control. In theory, this eliminates the need for an assistant staff member as the operator holds the retroreflector and controls the total station from the observed point. In practice however, an assistant surveyor is often needed when the surveying is being conducted in busy areas such as on a public carriageway or construction site. This is to prevent people from disrupting the total station as they walk past, which would neccesitate resetting the tripo ...
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Botanist And Students Examining The Species Distribution Using Quadrat
Botany, also called , 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 (''botanē'') meaning "pasture", " herbs" "grass", or " fodder"; is in turn derived from (), "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 (in the strict sense) study approximately 410,000 species of land plants of which some 391,000 species are vascular plants (including approximately 369,000 species of flowering plants), and approximately 20,000 are bryophytes. Botany originated in prehistory as herbalism with the efforts of early humans to identify – and later cultivate – edible, med ...
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Selection Bias
Selection bias is the bias introduced by the selection of individuals, groups, or data for analysis in such a way that proper randomization is not achieved, thereby failing to ensure that the sample obtained is representative of the population intended to be analyzed. It is sometimes referred to as the selection effect. The phrase "selection bias" most often refers to the distortion of a statistical analysis, resulting from the method of collecting samples. If the selection bias is not taken into account, then some conclusions of the study may be false. Types Sampling bias Sampling bias is systematic error due to a non-random sample of a population, causing some members of the population to be less likely to be included than others, resulting in a biased sample, defined as a statistical sample of a population (or non-human factors) in which all participants are not equally balanced or objectively represented. It is mostly classified as a subtype of selection bias, sometimes sp ...
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John Ernst Weaver
John Ernst Weaver ( 5 May 1884 – 8 June 1966) was an American botanist, prairie ecologist, and university professor. Biography Weaver was born in Villisca, Iowa. He obtained a PhD in Biology and Botany at the University of Minnesota, 1916. He was "Instructor of Botany" at Washington State College from 1912 to 1913. In 1915 he became "Assistant professor of Botany" at the University of Nebraska where he was a plant ecology professor from 1917 until his retirement in 1952. Weaver published many works regarding vegetation and ecology of prairies. According to his biography in ''Nebraska Authors'': Weaver is famous for his studies of the root systems of prairie plants. A student and collaborator of Frederic Clements at the University of Nebraska, he led the study of the responses of prairie plants and the Great Plains to the great drought of the 1930s. He co-authored several important botany textbooks with Clements, but moved beyond Clements' paradigm of plant succession and in ...
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Ecology
Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps with the closely related sciences of biogeography, evolutionary biology, genetics, ethology, and natural history. Ecology is a branch of biology, and it is not synonymous with environmentalism. Among other things, ecology is the study of: * The abundance, biomass, and distribution of organisms in the context of the environment * Life processes, antifragility, interactions, and adaptations * The movement of materials and energy through living communities * The successional development of ecosystems * Cooperation, competition, and predation within and between species * Patterns of biodiversity and its effect on ecosystem processes Ecology has practical applications in conservation biology, wetland management, natural resource managemen ...
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Arthur Tansley
Sir Arthur George Tansley FLS, FRS (15 August 1871 – 25 November 1955) was an English botanist and a pioneer in the science of ecology. Educated at Highgate School, University College London and Trinity College, Cambridge, Tansley taught at these universities and at Oxford, where he served as Sherardian Professor of Botany until his retirement in 1937. Tansley founded the ''New Phytologist'' in 1902 and served as its editor until 1931. He was a pioneer of the science of ecology in Britain, being heavily influenced by the work of Danish botanist Eugenius Warming, and introduced the concept of the ecosystem into biology. Tansley was a founding member of the first professional society of ecologists, the Central Committee for the Survey and Study of British Vegetation, which later organised the British Ecological Society, and served as its first president and founding editor of the ''Journal of Ecology''. Tansley also served as the first chairman of the British Nature Conservanc ...
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