[R-sig-eco] Applied Environmental Data Analyses: Water Chemistry and Biota

[Rich Shepard]

On Thu, 6 Dec 2012, alfredo tello wrote:

> Check out the R package Vegan tutorial by Jari Oksanen:
> http://cc.oulu.fi/~jarioksa/opetus/metodi/vegantutor.pdf. Vegan has
> several functions which I believe should allow you to address some of your
> questions.

Alfredo,

   I will certainly do this.

> I have not worked with functional groups, but I'm guessing you could treat
> them as you would treat taxa for statistical purposes(?)

   For benthic macroinvertebrates I'll strongly argue that functional feeding
groups are better than the mixed taxonomic levels that are usually given
equal weights. So yes, statistical models should work equally well,
particularly if the methods will work with percentages (proportions) which
normalize for different numbers of individuals in the different streams.

> I think Vegan's function 'adonis' might be of interest to you. It allows
> you to partition variation in a data/distance matrix according to
> specified factors (e.g., water chemistry).
>
> Hopet this helps!

   I'm sure it will.

Thanks very much,

Rich

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Richard B. Shepard, Ph.D.          |   Integrity - Credibility - Innovation
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