[R-sig-eco] transformation of percent coverage data in community analysis

[Marc Taylor]

Dear all,

A colleague of mine is doing some basic descriptive analyses of algal
community data (e.g. MDS, PCA), and we got to talking about how his data
(percent coverage) might be transformed before the calculation of distance
matrices. This may be desirable in order to reduce the influence of
dominant species in the analyses.

One extreme would be to convert the percent coverage matrices to
presence/absence, which would essentially remove all of the intra-sample
weighting, and concentrate on larger spatial presence patterns. I was
wondering if there were any other options that would make sense for such
data?

Thanks in advance for your advise,
Marc

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