strong {abdiv} | R Documentation |
Strong's dominance index measures the maximum departure between the observed proportions and a perfectly even community.
strong(x)
x |
A numeric vector of species counts. |
Strong's dominance index is defined as
D_W = \max_i \left [ \frac{b_i}{N} - \frac{i}{S} \right ],
where
b_i
is the abundance of the i
th species, ordered from smallest
to largest, N
is the total number of counts, and S
is the number
of species observed.
Equivalent to strong()
in skbio.diversity.alpha
.
Strong's dominance index, 0 \leq D_W < 1
. The index is
undefined if x
sums to 0, and we return NaN
in this case.
Strong WL. Assessing species abundance uneveness within and between plant communities. Community Ecology. 2002;3:237-246.
x <- c(9, 0, 1, 2, 5, 2, 1, 1, 0, 7, 2, 1, 0, 1, 1)
strong(x)