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en:alpha_diversity

Alpha diversity

FIXME Diversity of community consists of richness and evenness, where richness represents number of species, while evenness represents differences in relative abundances of individual species. Several commonly used diversity indices differ in a way how they cope with each of these two parameters.

Species richness

S~=~number of species

Shannon entropy

H_Sh~=~-sum{i=1}{S}{p_i~ln(p_i)}

Simpson concentration index

H_S~=~sum{i=1}{S}{{p_i}^2}

Hill numbers

{}^q{D}~=~(sum{i=1}{S}{{p_i}^q})^{1/(1-q)}

{}^0{D}~=~S (species richness)

{}^1{D}~=~e^{H_Sh} (exponential of Shannon entropy)

{}^2{D}~=~1/H_S (reciprocal of Simpson's concentration index)

en/alpha_diversity.txt · Last modified: 2016/06/28 10:29 (external edit)