duarm {labdsv}R Documentation

Indicator Species Analysis Minimizing Partial Occurrences

Description

Calculates the degree to which species are either always present or always absent within clusters or types.

Usage

duarm(taxa,clustering,sort=FALSE)

Arguments

taxa a matrix or dataframe of samples, species as columns, samples as rows
clustering a vector of numeric cluster memberships for samples, or a classification object returned from pam, or partana
sort if TRUE, return in order of highest value to lowest rather than input order

Details

Calculates the constancy (fractional occurrence of each species in every type), and then calculates twice the the sum of the absolute values of the constancy - 0.5, normalized to the number of clusters (columns).

Value

a dataframe of species indicator values

Note

The name duarm is a horrible pun on the name duleg, which is an abbreviation for Dufrene and Legendre who defined an alternative indicator species algorithm.

Author(s)

David W. Roberts droberts@montana.edu http://ecology.msu.montana.edu/droberts

References

http://ecology.msu.montana.edu/labdsv/R

See Also

duleg

Examples

    data(bryceveg)
    dis.bc <- dsvdis(bryceveg,'bray/curtis')
    clust <- sample(1:5,nrow(bryceveg),replace=TRUE)
    duarm(bryceveg,clust)

[Package labdsv version 1.2-2 Index]