margalef {abdiv} | R Documentation |
Margalef's richness index
margalef(x)
x |
A numeric vector of species counts. |
For a vector x
of species counts, Margalef's index is
D = \frac{S -1}{\log N},
where S
is the total number of species
observed and N
is the total number of counts.
This index is appropriate only for raw counts, not transformed counts or proportions.
Equivalent to margalef()
in skbio.diversity.alpha
.
The value of Margalef's index, D \geq 0
. This index is
undefined when the total number of counts is 1 or 0, in which case we
return NaN
.
Margalef R. Information theory in ecology. General Systems 3. 1958;36-71.
x <- c(15, 6, 4, 0, 3, 0)
margalef(x)