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Menu: Edit | Add diversity index values

 

This option servers to calculate diversity index values (Richness, Shannon diversity, Evenness, Simpson's index of diversity) of each relevé and stores these data in separate columns in the database. If the columns are not yet present, they will be added automatically to the database.

 

Range of relevés: Specify the range of relevé numbers on which you want to perform the calculations.

 

Add columns for…: Specify which index values have to be calculated.

 

Add: Execute the calculation. The extra columns will be added at the end of the table with header data.

 

 

Calculations

 

ni: the abundance of species i

S: the number of species in a relevé (= Richness-index)

pi: the relative abundance of each species (as percentage cover), calculated as the proportion of the total number of species (S)

 

Shannon-index = - ∑( pi * Ln(pi) )
Eveness-index = Shannon-index / Ln(S)

Simpson-index = 1 - ∑(pi2)