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Biodiversity is usually plotted as taxonomic richness of a geographic area, with some reference to a temporal scale. Whittaker [9] described three common metrics used to measure species-level biodiversity, encompassing attention to species richness or species evenness: Species richness - the simplest of the indices available. Simpson index
The observed species richness is affected not only by the number of individuals but also by the heterogeneity of the sample. If individuals are drawn from different environmental conditions (or different habitats), the species richness of the resulting set can be expected to be higher than if all individuals are drawn from similar environments.
The logic behind the derivation of the logseries is varied [15] however Fisher proposed that sampled species abundances would follow a negative binomial from which the zero abundance class (species too rare to be sampled) was eliminated. [1] He also assumed that the total number of species in a community was infinite.
Here is a constant which depends on the unit used for area measurement, and equals the number of species that would exist if the habitat area was confined to one square unit. The graph looks like a straight line on log–log axes , and can be linearized as:
Species richness, or biodiversity, increases from the poles to the tropics for a wide variety of terrestrial and marine organisms, often referred to as the latitudinal diversity gradient. [1] The latitudinal diversity gradient is one of the most widely recognized patterns in ecology. [1] It has been observed to varying degrees in Earth's past. [2]
abundance class 1 1-2 2-4 4-8 8-16 species 5 0 1.5 1.5 1 The three species of abundance four thus appear, 1.5 in abundance class 2–4, and 1.5 in 4–8. The above method of analysis cannot account for species that are unsampled: that is, species sufficiently rare to have been recorded zero times.
Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time.Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, isolation and habitat area. [1]
Citizen science, also known as public participation in scientific research, has been widely used in environmental sciences and is particularly popular in a biodiversity-related context. It has been used to enable scientists to involve the general public in biodiversity research, thereby enabling the scientists to collect data that they would ...