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Menampilkan postingan dari Mei, 2017

Biodiversity indices

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1.     Dominance Measure of diversity whick takes into account both richness and evenness of species. It is often used to quantify the biodiversity of a habitat. A community dominated by one or two species is considered to be less diverse than one in which several different species have a similar abundance. Simpson's Diversity Index is a measure of diversity which takes into account the number of species present, as well as the relative abundance of each species. As species richness and evenness increase, so diversity increases. 2.     Eveness Species evenness refers to how close in numbers each species in an environment is mathematically it is defined as a diversity index , a measure of biodiversity which quantifies how equal the community is numericall. 3.     Species richnes Richness R simply quantifies how many different types the dataset of interest contains. For example, species richness (usually noted S ) of a dataset is the number of different

quantitative ecology

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Biological Diversity - the great variety of life Biological diversity can be quantified in many different ways. The two main factors taken into account when measuring diversity are richness and evenness. Richness is a measure of the number of different kinds of organisms present in a particular area. For example, species richness is the number of different species present. However, diversity depends not only on richness, but also on evenness. Evenness compares the similarity of the population size of each of the species present. 1. Richness The number of species per sample is a measure of richness. The more species present in a sample, the 'richer' the sample. Species richness as a measure on its own takes no account of the number of individuals of each species present. It gives as much weight to those species which have very few individuals as to those which have many individuals. Thus, one daisy has as much influence on the richness of an area as 1000 buttercups