Mahnaz--
I believe that the lack of reply to your question to R-sig-ecology is
because it is not an R question, and you did not provide enough information
for anyone to give you a useful answer if they were so inclined.

Whether your data require transformation (e.g., square-root to reduce the
emphasis on the most abundant species, or sum-to-one because of how they
were collected, or standardization to equal means) depends on what your
response variable is (counts of individuals, biomass, percent cover for
benthic organisms, etc.), and what
The need to transform your species(?) response measurements before CCA is
not a computational requirement for CCA, but may be required in order for
the CCA results to be meaningful.  If you have strong reasons for applying
CCA instead of other approaches, you might start with Mike Palmer's website:
http://ordination.okstate.edu/

Also, if you can access google scholar, searching on "CCA ordination
transformation"
I hope that this at least points you in the direction of several articles
such as Legendre & Gallagher 2001, although most hits are aimed at
vegetation, not fish or marine benthic composition.

I hope that this at least points you in the right direction.

Tom 2

On Sat, Jan 19, 2013 at 11:04 PM, Mahnaz Rabbaniha <rab.mahnaz@gmail.com>wrote:

> Dear sig-eco users,
>
> Hi
> I would like to do cca in vegan package,the main question is about the
> response variable, there are a variety from 0 to 1300, it is necessary
> transformed them before the analyses or used in original form.
>
> thank you in advance for answering
>
> --
> Mahnaz Rabbaniha
> marine ecology PhD
> Iranian Fisheries Research Organization (IFRO)
> P.O.Box: 14155-6116 , P.Code: 1411816618*
> Tehran, IRAN
> Phone:   +98 21 44580953
> Fax:       +98 21 44580583
> Mobile:  +98 912 5790377
>
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>
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>



-- 
-------------------------------------------
Tom Philippi, Ph.D.
Quantitative Ecologist & Data Therapist
Inventory and Monitoring Program
National Park Service
(619) 523-4576
Tom_Philippi@nps.gov
http://science.nature.nps.gov/im/monitor

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