Skip to content
Prev 130 / 7420 Next

variance partition in vegan

On Tue, May 27, 2008 at 05:30:15PM +0200, Alejandro Gonz?lez wrote:
I don't think the results will be strictly the same. The vegan
function varpart provides the unbiased estimators of the variation
partitions, as described by Peres-Neto et al. 2006 (reference below).
I could be wrong, but I think using CANOCO will provide the biased
estimates.
I think the second part of your question is whether or not varpart
incorporates variable selection? It doesn't, but there are several
options available in R. The one closest to what CANOCO does is
probably the packfor package, written by Stephane Dray
(http://biomserv.univ-lyon1.fr/~dray/software.php). This package
incorporates the improvements described by Blanchet et al. 2008
(manuscript at
http://www.bio.umontreal.ca/legendre/reprints/index.html).

So, if the results from vegan differ from Canoco it's because vegan
uses improved techniques. If anyone knows different please let me
know, as I'm spending a lot of time lately working with these
functions!


Cheers,

Tyler

@Article{peres-neto_legendre_ea_2006,

  author = {Pedro R. Peres-Neto and Pierre Legendre and St\'{e}phane
            Dray and Daniel Borcard},

  title = {Variation partitioning of species data matrices: estimation
           and comparison of fractions},

  journal =	 {Ecology},
  year =	 2006,
  volume =	 87,
  number =	 10,
  pages =	 {2614--2625}
}