C_ratio: Variance ratio of Schluter (1984)

In petrkeil/spasm: Species association measures for various data types

Description

This is the classical variance ratio function; the function is applicable to both incidence and abundance matrices. Note: Before the calculation, species (rows) with zero occurrences, and sites (columns) with zero species are removed from m.

Usage

C_ratio(m, clean = TRUE)

Arguments

m	Community data matrix with species as rows and sites as columns. Can contain either incidences (1/0) or abundances (natural numbers).
clean	Logical. Do you want to remove zero-sum rows or columns? When the index needs the "d" fraction (sites where no species occurs), only zero-sum rows are removed.

Value

A single number, the variance ratio.

References

Schluter, D. 1984. A variance test for detecting species associations, with some example applications. Ecology 65: 998-1005.

petrkeil/spasm documentation built on Jan. 15, 2021, 6:08 p.m.