Skip to main content

Table 1 Proposed evenness indices varying over the interval from 0 to 1 and based on the species abundance probabilities (proportions) p 1, …, p S and species richness S

From: Evenness indices once again: critical analysis of properties

Designation

Formula

Reference

Notes

E 1

\( H/ logS=-{\displaystyle \sum_{i=1}^S{p}_i log{p}_i/ logS} \)

Pielou (1966)

 

E 2

(e H − 1)/(S − 1)

Heip (1974)

a

E 3

\( \Big(1-{\displaystyle \sum_{i=1}^S{p}_i^2\Big)/\left(1-1/S\right)} \)

Smith and Wilson (1996)

 

E 4

\( - log{\displaystyle \sum_{i=1}^S{p}_i^2/ logS} \)

Smith and Wilson (1996)

 

E 5

\( \Big(1/{\displaystyle \sum_{i=1}^S{p}_i^2-1\Big)/\left({e}^H-1\right)} \)

Alatalo (1981)

a

E 6

\( \left(1-\sqrt{{\displaystyle \sum_{i=1}^S{p}_i^2}}\right)/\left(1-\sqrt{1/S}\right) \)

Pielou (1969)

 

E 7

\( \Big(1/{\displaystyle \sum_{i=1}^S{p}_i^2-1\Big)/\left(S-1\right)} \)

Kvålseth (1991)

 

E 8

\( \left({\displaystyle \sum_{i=1}^S \min \left\{{p}_i,1/S\right\}-1/S}\right)/\left(1-1/S\right) \)

Bulla (1994)

 

E 9

\( 1-{\left[\left(S{\displaystyle \sum_{i=1}^S{p}_i^2-1}\right)/\left(S-1\right)\right]}^{1/2} \)

Williams (1977)

b

E 10

\( 2{\displaystyle \sum_{i=1}^S\left(i-1\right){p}_i/\left(S-1\right)} \)

Solomon (1979)

c

E 11

\( \left(1-{\displaystyle \sum_{i=1}^S{p}_i/i}\right)/\left[1-\left(1/S\right){\displaystyle \sum_{i=1}^S1/i}\right] \)

New

c

  1. Notes: a. The H stands for the Shannon (1948) entropy defined for E 1 and with base-e (natural) logarithms (E 1 and E 4 are indifferent as to which logarithm is used).
  2. b. Engen (1979) attributed this index to F.M. Williams (1977) in an unpublished manuscript.
  3. c. The p i ’s are here in descending order (p 1 ≥ p 2 ≥ … ≥ p S ).