tabula (version 3.3.0)

evenness: Evenness

Description

Computes an evenness measure.

Usage

evenness(object, ...)
# S4 method for matrix
evenness(
  object,
  ...,
  method = c("shannon", "simpson", "brillouin", "mcintosh")
)
# S4 method for data.frame
evenness(
  object,
  ...,
  method = c("shannon", "simpson", "brillouin", "mcintosh")
)

Value

An EvennessIndex object.

Arguments

object

A \(m \times p\) numeric matrix or data.frame of count data (absolute frequencies giving the number of individuals for each category, i.e. a contingency table). A data.frame will be coerced to a numeric matrix via data.matrix().

...

Further arguments to be passed to internal methods (see below).

method

A character string specifying the index to be computed (see details). Any unambiguous substring can be given.

Author

N. Frerebeau

Details

Evenness is a measure of how evenly individuals are distributed across the sample.

The following evenness measures are available (see Magurran 1988 for details):

brillouin

Brillouin diversity index.

mcintosh

McIntosh dominance index.

shannon

Shannon-Wiener diversity index.

simpson

Simpson dominance index.

References

Magurran, A. E. (1988). Ecological Diversity and its Measurement. Princeton, NJ: Princeton University Press. tools:::Rd_expr_doi("10.1007/978-94-015-7358-0").

See Also

index_brillouin(), index_mcintosh(), index_shannon(), index_simpson()

Other diversity measures: diversity(), heterogeneity(), occurrence(), plot.DiversityIndex(), plot.RarefactionIndex(), profiles(), rarefaction(), richness(), she(), similarity(), simulate(), turnover()

Examples

## Data from Conkey 1980, Kintigh 1989
data("cantabria")

## Alpha diversity
diversity(cantabria)

## Shannon diversity index
(h <- heterogeneity(cantabria, method = "shannon"))
(e <- evenness(cantabria, method = "shannon"))

as.data.frame(h)