Message-ID: <30A9CCE0A986F74C837D6F87F9C581862806F42B@WPVEXCMBX01.purdue.lcl>
Date: 2014-11-08T23:24:06Z
From: Holland, Jeffrey D
Subject: adonis with blocking (not nesting)
Dear R for ecology experts,
I have found many discussions online about blocking and nesting in adonis, but no answers for blocking. I have community data with abundances within 42 aquatic genera (final.fd[,9:36]) from 2 types of streams (type). Stream samples were paired (pair) as a blocking factor. So the individual samples (n=12; I know, permuations will be limited) are one of two types and blocked within pairs. I am using strata to restrict permuations within the blocking factor. However, I haven't found a way to specify the blocking in the data structure.
If I use paired=T, how do I specify the pairing variable?
adonis(final.fd[,9:42] ~ final.fd$type, paired=T, method = "bray", strata=final.fd$pair)
If there is another way to set the blocking factor, what is it?
Much appreciated all,
Jeff
Jeffrey D. Holland, jdhollan at purdue.edu
Assoc. Prof., Dept. of Entomology
Purdue University