[R-sig-eco] repeated measures NMDS?

[Eduard Szöcs]

Hi listers,

I have species and environmental data for 24 sites that were sampled thrice. If I want to analyze the data with NMDS I could run metaMDS on the whole dataset (24 sites x 3 times = 72) and then fit environmental data, but this would be some kind of pseudoreplication given that the samplings are not independent and the gradients may be overestimated, wouldn`t it?

For environmental data a factor could be included for the sampling dates - but this would not be possible for species data.

Is there an elegant way either to aggregate data before ordination or to conduct sth. like a repeated measures NMDS?

Thank you in advance,
Eduard Szöcs