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Species–area Relationship
The species-area relationship or species-area curve describes the relationship between the area of a habitat, or of part of a habitat, and the number of species found within that area. Larger areas tend to contain larger numbers of species, and empirically, the relative numbers seem to follow systematic mathematical relationships.Preston, F.W. 1962. The canonical distribution of commonness and rarity: Part I. Ecology 43:185–215 and 410–432. The species-area relationship is usually constructed for a single type of organism, such as all vascular plants or all species of a specific trophic level within a particular site. It is rarely if ever, constructed for all types of organisms if simply because of the prodigious data requirements. It is related but not identical to the species discovery curve. Ecologists have proposed a wide range of factors determining the slope and elevation of the species-area relationship.Rosenzweig, M.L. 1995. Species Diversity in Space and Time. Cambrid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SAR(Species-area Curve)
SAR or Sar may refer to: Places * Sar (river), Galicia, Spain * Sar, Bahrain, a residential district * Sar, Iran (other), several places in Iran * Sar, Tibet, Tibet Autonomous Region of China * Šar Mountains, in southeastern Europe * Syrian Arab Republic, sometimes abbreviated as SAR Business and finance * Parabolic SAR (stop and reverse), a method of technical stock analysis * Saudi riyal, currency code SAR * Stock appreciation right, an employee reward Computing * Segmentation and reassembly, in data networks * Service Archive or SAR, a file format related to JAR * Shift Arithmetically Right (SAR), an x86 instruction * Storage Aspect Ratio of a digital image * sar (Unix), or system activity report, a Unix/Linux performance report utility Law enforcement * Search and rescue * Nationwide Suspicious Activity Reporting Initiative, US * Suspicious activity report, by a financial institution to an authority Science Medicine, psychology, and biology * Scaff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species-abundance Distribution
In the field of ecology, the relative abundance distribution (RAD) or species abundance distribution describes the relationship between the number of species observed in a field study as a function of their observed abundance. The graphs obtained in this manner are typically fitted to a Zipf–Mandelbrot law, the exponent of which serves as an index of biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ... in the ecosystem under study. Notes and references Ecological metrics {{ecology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unified Neutral Theory Of Biodiversity
The unified neutral theory of biodiversity and biogeography (here "Unified Theory" or "UNTB") is a theory and the title of a monograph by ecologist Stephen P. Hubbell. It aims to explain the diversity and relative abundance of species in ecological communities. Like other neutral theories of ecology, Hubbell assumes that the differences between members of an ecological community of trophically similar species are "neutral", or irrelevant to their success. This implies that niche differences do not influence abundance and the abundance of each species follows a random walk. The theory has sparked controversy, and some authors consider it a more complex version of other null models that fit the data better. "Neutrality" means that at a given trophic level in a food web, species are equivalent in birth rates, death rates, dispersal rates and speciation rates, when measured on a per-capita basis. This can be considered a null hypothesis to niche theory. Hubbell built on earlier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Storage Effect
The storage effect is a coexistence mechanism proposed in the ecological theory of species coexistence, which tries to explain how such a wide variety of similar species are able to coexist within the same ecological community or guild. The storage effect was originally proposed in the 1980s to explain coexistence in diverse communities of coral reef fish, however it has since been generalized to cover a variety of ecological communities. The theory proposes one way for multiple species to coexist: in a changing environment, no species can be the best under all conditions. Instead, each species must have a unique response to varying environmental conditions, and a way of buffering against the effects of bad years. The storage effect gets its name because each population "stores" the gains in good years or microhabitats (patches) to help it survive population losses in bad years or patches. One strength of this theory is that, unlike most coexistence mechanisms, the storage effec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species Richness
Species richness is the number of different species represented in an ecological community, landscape or region. Species richness is simply a count of species, and it does not take into account the abundances of the species or their relative abundance distributions. Species richness is sometimes considered synonymous with species diversity, but the formal metric species diversity takes into account both species richness and species evenness. Sampling considerations Depending on the purposes of quantifying species richness, the individuals can be selected in different ways. They can be, for example, trees found in an inventory plot, birds observed from a monitoring point, or beetles collected in a pitfall trap. Once the set of individuals has been defined, its species richness can be exactly quantified, provided the species-level taxonomy of the organisms of interest is well enough known. Applying different species delimitations will lead to different species richness values ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scaling Pattern Of Occupancy
In spatial ecology and macroecology, scaling pattern of occupancy (SPO), also known as the area-of-occupancy (AOO) is the way in which species distribution changes across spatial scales. In physical geography and image analysis, it is similar to the modifiable areal unit problem. Simon A. Levin (1992) states that ''the problem of relating phenomena across scales is the central problem in biology and in all of science''. Understanding the SPO is thus one central theme in ecology. Pattern description This pattern is often plotted as log-transformed grain (cell size) versus log-transformed occupancy. Kunin (1998) presented a log-log linear SPO and suggested a fractal nature for species distributions. It has since been shown to follow a logistic shape, reflecting a percolation process. Furthermore, the SPO is closely related to the intraspecific occupancy-abundance relationship. For instance, if individuals are randomly distributed in space, the number of individuals in an ''α''- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymptote
In analytic geometry, an asymptote () of a curve is a line such that the distance between the curve and the line approaches zero as one or both of the ''x'' or ''y'' coordinates tends to infinity. In projective geometry and related contexts, an asymptote of a curve is a line which is tangent to the curve at a point at infinity. The word asymptote is derived from the Greek ἀσύμπτωτος (''asumptōtos'') which means "not falling together", from ἀ priv. + σύν "together" + πτωτ-ός "fallen". The term was introduced by Apollonius of Perga in his work on conic sections, but in contrast to its modern meaning, he used it to mean any line that does not intersect the given curve. There are three kinds of asymptotes: ''horizontal'', ''vertical'' and ''oblique''. For curves given by the graph of a function , horizontal asymptotes are horizontal lines that the graph of the function approaches as ''x'' tends to Vertical asymptotes are vertical lines near which the fun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Josias Braun-Blanquet
Josias Braun-Blanquet (3 August 1884 – 20 September 1980) was an influential phytosociologist and botanist. Braun-Blanquet was born in Chur, Switzerland and died in Montpellier, France. Biography Work In Josias Braun-Blanquet's dissertation, supervised by Charles Flahault, he worked on the phytosociology of the southern Cévennes. Subsequently he established the modern way of classifying vegetation according to floristic composition. This is what makes him one of the most influential botanists until today.Nicolson, M. (1993). National Styles, Divergent Classifications: A comparative case study from the history of French and American plant ecology. Knowledge and Society: Studies in the Sociology of Science Past and Present, 8, 139-186. Braun-Blanquet's way of classifying a plant community uses the scientific name of its most characteristic species as namesake, changing the ending of the generic name to "-etum" and treating the specific epithet as adjective. Thus, a particular t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytosociology
Phytosociology, also known as phytocoenology or simply plant sociology, is the study of groups of species of plant that are usually found together. Phytosociology aims to empirically describe the vegetative environment of a given territory. A specific community of plants is considered a social unit, the product of definite conditions, present and past, and can exist only when such conditions are met. In phyto-sociology, such a unit is known as a phytocoenosis (or phytocoenose). A phytocoenosis is more commonly known as a plant community, and consists of the sum of all plants in a given area. It is a subset of a biocoenosis, which consists of all organisms in a given area. More strictly speaking, a phytocoenosis is a set of plants in area that are interacting with each other through competition or other ecological processes. Coenoses are not equivalent to ecosystems, which consist of organisms and the physical environment that they interact with. A phytocoensis has a distribution whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semilog Graph
In science and engineering, a semi-log plot/graph or semi-logarithmic plot/graph has one axis on a logarithmic scale, the other on a linear scale. It is useful for data with exponential relationships, where one variable covers a large range of values, or to zoom in and visualize that - what seems to be a straight line in the beginning - is in fact the slow start of a logarithmic curve that is about to spike and changes are much bigger than thought initially.(1) (2) All equations of the form y=\lambda a^ form straight lines when plotted semi-logarithmically, since taking logs of both sides gives :\log_a y = \gamma x + \log_a \lambda. This is a line with slope \gamma and \log_a \lambda vertical intercept. The logarithmic scale is usually labeled in base 10; occasionally in base 2: :\log (y) = (\gamma \log (a)) x + \log (\lambda). A log–linear (sometimes log–lin) plot has the logarithmic scale on the ''y''-axis, and a linear scale on the ''x''-axis; a linear-log (sometimes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Gleason
Henry Allan Gleason (1882–1975) was an American ecologist, botanist, and taxonomist. He was known for his endorsement of the individualistic or open community concept of ecological succession, and his opposition to Frederic Clements's concept of the climax state of an ecosystem. His ideas were largely dismissed during his working life, leading him to move into plant taxonomy, but found favour late in the twentieth century. Life and work Gleason was born in Dalton City, Illinois, and after undergraduate and master's work at the University of Illinois earned a PhD from Columbia University in Biology in 1906. He held faculty positions at the University of Illinois, the University of Chicago and the University of Michigan, before returning to the East Coast, to the New York Botanical Garden in the Bronx, New York, where he remained for the rest of his career, until 1950. In Gleason's early ecological research on the vegetation of Illinois, around 1909-1912, he worked largely wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
