pianka_skew: PiankaSkew Niche Overlap Metric

In EcoSimR: Null Model Analysis for Ecological Data

Description

Takes a niche utilization matrix returns the skewness of the Pianka pairwise niche overlap index.

Usage

pianka_skew(m = matrix(rpois(80, 1), nrow = 10))

Arguments

m	a matrix of resource utilization values.

Details

A large positive value for skewness implies that there are more species pairs with high than low niche overlap. A large negative value for skewness implies there are more species pairs with low than high niche overlap. The performance of this algorithm has not been thoroughly tested with real data sets.

Value

Returns the skewness of the average pairwise niche overlap.

Note

The resource utilization matrix (rows = species, columns = discrete resource categories) may include zeroes, but no negative numbers or missing values. Relative resource within a species is first calculated, so the rows need not sum to 1.0.

References

Winemiller, K.O. and E.R. Pianka. 1990. Organization in natural assemblages of desert lizards and tropical fishes. Ecological Monographs 60: 27-55.

See Also

pianka niche overlap index.

Examples

obsSkew<- pianka_skew(m=matrix(rpois(40,0.5),nrow=8))

Example output

Loading required package: MASS

EcoSimR documentation built on May 2, 2019, 7:26 a.m.