calc_PIE: Calculate probability of interspecific encounter (PIE)

In MoBiodiv/mobr: Measurement of Biodiversity

Calculate probability of interspecific encounter (PIE)

Description

calc_PIE returns the probability of interspecific encounter (PIE) which is also known as Simpson's evenness index and Gini-Simpson index.

Usage

calc_PIE(x, PIE_replace = FALSE)

Arguments

x	can either be a: 1) mob_in object, 2) community matrix-like object in which rows represent plots and columns represent species, or 3) a vector which contains the abundance of each species.
PIE_replace	if TRUE, sampling with replacement is used. Otherwise, sampling without replacement (default).

Details

By default, Hurlbert's (1971) sample-size corrected formula is used:

PIE = N /(N - 1) * (1 - sum(p_i^2))

where N is the total number of individuals and p_i is the relative abundance of species i. This formulation uses sampling without replacement (replace = FALSE ) For sampling with replacement (i.e., the sample-size uncorrected version), set replace = TRUE.

In earlier versions of mobr, there was an additional argument (ENS) for the conversion into an effective number of species (i.e S_PIE). Now, calc_SPIE has become its own function and the (ENS) argument is no longer supported . Please, use calc_SPIE instead.

Value

either a single PIE value or vector of PIE values.

Author(s)

Dan McGlinn, Thore Engel

References

Hurlbert, S. H. (1971) The nonconcept of species diversity: a critique and alternative parameters. Ecology 52, 577-586.

See Also

calc_SPIE

Examples

data(inv_comm)
calc_PIE(inv_comm)
calc_PIE(inv_comm, PIE_replace = TRUE)
calc_PIE(c(23,21,12,5,1,2,3))
calc_PIE(c(23,21,12,5,1,2,3), PIE_replace = TRUE)

MoBiodiv/mobr documentation built on Oct. 26, 2024, 10:51 a.m.