simpson {untb}R Documentation

Simpson's diversity index

Description

Simpson's diversity index

Usage

simpson(x)

Arguments

x Ecosystem vector; coerced to class count

Details

Returns the Simpson index D: the probability that two randomly sampled individuals belong to different species. This is

1-sum((p_i)^2)

where p_i is the relative frequency of the i-th species

Note

Early versions of the untb package effectively defined D as the probability that two randomly selected different individuals belong to different species

Author(s)

Robin K. S. Hankin

References

See Also

preston

Examples

data(butterflies)

D <- simpson(butterflies)
theta <- optimal.prob(butterflies)*2*no.of.ind(butterflies)

#compare theta with D/(1-D) (should be roughly equal):

theta
D/(1-D)

[Package untb version 1.4-2 Index]