hpie: Hurlbert's Probability of Interspecific Encounter (PIE)

In benthos: Marine Benthic Ecosystem Analysis

Hurlbert's Probability of Interspecific Encounter (PIE)

Description

The probability that two individuals selected at random (without replacement) from a sample will belong to different species is given by (Hurlbert, 1971, p.579, Eq. 3):

Δ1 = ∑_{i=1}^S (N[i]/N)((N-N[i])(N-1)) = (N/(N-1))Δ2

where Δ2 (Hurlbert, 1971, p.579, Eq. 4) is the probability that two individuals selected at random (with replacement) from a sample will belong to different species:

Δ2 = 1 - ∑_{i=1}^S π[i]^2

where N[i] is the number of individuals of the ith species in the community, N is the total number of individuals in the community, π[i] = N[i]/N, and S is the number of species in the community. Note that Hurlbert's PIE hpie is the complement of simpson.

Usage

hpie(.data = NULL, taxon, count)

hpie_(.data = NULL, taxon, count)

Arguments

.data	data in a data.frame, tibble, data.table, database etc.
taxon	name of column in .data containing taxa
count	name of column in .data containing counts

Value

A numeric vector with the probability of interspecific encounter (PIE).

Functions

• hpie_(): suitable for calling from a function (see package lazyeval).

References

Hurlbert, S.H., 1971. The Nonconcept of Species Diversity: A Critique and Alternative Parameters. Ecology 52:577-586.

See Also

simpson, hurlbert

Examples

     hpie(
         taxon = c("Euspira pulchella", "Nephtys cirrosa"), 
         count = c(6, 12)
     )
 

benthos documentation built on Aug. 22, 2022, 5:07 p.m.