How is Pielou evenness calculated?

How is Pielou evenness calculated?

evenness: Pielou’s measure of species evenness Calculates Pielou’s measure of species evenness, i.e. J = H’/ln(S) where H’ is Shannon Weiner diversity and S is the total number of species in a sample, across all samples in dataset.

What is the formula of evenness?

Divide Shannon’s diversity index H by natural logarithm of species richness ln(S) to calculate the species evenness. In the example, 0.707 divided by 1.099 equals 0.64. Note that species evenness ranges from zero to one, with zero signifying no evenness and one, a complete evenness.

What is Pielou evenness index?

Pielou’s evenness is an index that measures diversity along with species richness. While species richness is the number of different species in a given area, evenness is the count of individuals of each species in an area. A calculated value of Pielou’s evenness ranges from 0 (no evenness) to 1 (complete evenness).

How do you measure species evenness?

Species evenness takes into account the number of species and the relative abundance of species in a community. Several indices have been proposed. Two of the commonly used measures of evenness are the Shannon index (H) and the Simpson index (D).

What is the Shannon Wiener index equation?

Sample Calculations: The Shannon-Wiener Diversity Index, H, is calculated using the following equation: H = -å Pi(lnPi) where Pi is the proportion of each species in the sample. A value near 4.6 would indicate that the number of individuals are evenly distributed between all the species.

How do you measure species richness and species evenness in a habitat?

There are two components of specieslevel biodiversity: Species richness: The number of species present in an area. Species evenness: A measure of the relative numbers of individuals in each species. They can both be measured by taking random samples from the habitat.

What is evenness in ecology?

Species evenness is a description of the distribution of abundance across the species in a community. Species evenness is highest when all species in a sample have the same abundance. Evenness approaches zero as relative abundances vary.

How do you calculate equitability?

Shannon’s equitability (EH) can be calculated by dividing H by Hmax (here Hmax = lnS). Equitability assumes a value between 0 and 1 with 1 being complete evenness. Example: The graph below shows H and EH for four hypothetical communities, each consisting of 100 individuals.

How do you calculate the evenness index?

The Shannon evenness index, abbreviated as SEI, provides information on area composition and richness. It covers the number of different land cover types (m) observed along the straight line and their relative abundances (Pi). It is calculated by dividing the Shannon diversity index by its maximum (h (m)).

What contributes to species evenness?

The more equal species are in proportion to each other, the greater the evenness of the site. If a community has a large disparity between the number of individuals within each species, it has low evenness. If the number of individuals within a species is fairly constant through out the community it has high evenness.

How do you calculate pi in ecology?


  1. In the formula, pi is the number of a particular kind of plant divided by the total number of plants observed.
  2. Complete the formula by multiplying the values in the third and fourth columns.
  3. Using the calculator, find the log of pi.