|||
Formula as follow:
where Dm is McIntosh diversity index,N is the total number of individuals in the plant population,
Ni is the number of individuals of the ith species.
R function as follow:
#A R function for calculating the mcIntosh diversity index
mcIntosh<-function(x,MARGIN = 1){
x <- drop(as.matrix(x))
if (length(dim(x)) > 1) {
total <- apply(x, MARGIN, sum)
Dm<-(total-(rowSums(x^2))^0.5)/(total-total^0.5)
}
else {
Dm <- (sum(x)-(sum(x^2))^0.5)/(sum(x)-sum(x)^0.5)}
return(Dm)
}
Example:
library(vegan)
data(BCI)
mcIntosh(BCI)
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