Re: co-inertie

From: Stephane DRAY (
Date: Fri Dec 05 2003 - 19:07:44 MET

You can apply coinertia anlysis on two faunistic tables. In theory, you can
not apply COI on two CA because you need to have common row weights. If you
make two CA, the row weights are different. But, C. ter Braak has break
this statement and will propose a co-corespondence analysis (to be
published in Ecology). In his paper, he includes an appendix to say how to
perform the computation with ADE 4 !!!!!
However, I am not sure that you need to perform two CA. Perhaps two nsca or
pca could be suitable. What are the objectives of your study ? What are the
two tables : same sites with different species or with same species.

At 08:11 05/12/2003, Sara Mouro wrote:
>Est' ce que il est logique et correct en utiliser la analyse de co-inertie
>por evaluer la similitude de 2 tableus floristiques?
>Est' ce que l'analyse de co-inertie est prope seulement pour comparer
>tableu de vegetation avec une tableu de variables environmentales?
>Chaque tableu de variables floristiques doit etre préablement traité selon
>une AFC?
>Vous avez d'autres suggestion por evaluer la similitude des 2 tablues de
>varoiables foristiques?
>J'ai deja fait le between-groups PCA et le within-group PCA (ou 1 group
>correspond a 1 tableu floristicque anterieur) mais je pense que la fort
>variabilité "interne" de chaque group peut contribuir par la aparent
>similitude des (between) groups.
>Merci d'avance...
>Sara Mouro.

Stéphane DRAY

Département des Sciences Biologiques
Université de Montréal, C.P. 6128, succursale centre-ville
Montréal, Québec H3C 3J7, Canada

Tel : 514 343 6111 poste 1233
E-mail :


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