correaltion ratios of the RLQ analysis

From: Byungok Ahn (
Date: Thu Oct 18 2001 - 10:25:37 MEST

Dear ADElist,

I would like to thank Sylvain DolÚdec for all the help that I received from him (or her).

I have still two questions in relation to the RLQ analysis:

1. Inspite of Sylvain DolÚdec┤s advice I failed in getting any graphic which is close to Fig. 18 in Doc (positions of species traits on the first ordination axis of the RLQ). So it was necessary to follow the method using the first two axes as presented in Barbaro et al. (2000). I operated the modules as follows:

 a. ordination of environmental variables along the first two RLQ axes

        XY coordinates file: .&&l1
        Categories file: .cat file from MCA of env. variables
        Row weigts file: .cmpl file from MCA of env. variables

 b. ordination of species traits along the first two RLQ axes
        XY coordinates file: .&&l2
        G values file: xxF file from FCA of species traits

Sylvain DolÚdec already mentioned that this method does not allow entirely correct graphs. If this graphics may not be used for my paper, what can be an alternative? The results I have now seem to be relative resonable when I check these graphics.

 2. My second question deals with the representation of correaltion ratios between species traits (or env. variables) and the first two RLQ axes. Could you please point me how to find the files indicating the correlation ratios?

All the very best,

Byungok Ahn
University of Essen
Institute of Ecology
Department of Hydrobiology
D-45117 Essen
Phone: +49/2 01/1 83-43 93
Fax: +49/2 01/1 83-44 42

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