Contrasts for Adonis in Vegan

Hi guys,

Just wandered if anyone can help regards contrasts for   adonis in the 
Vegan package.

I am running the following code for adonis

adonis(formula = resp ~ roostfact + impactfact + sppfact, data = alldata, 
permutations = 999, method = "euclidean")

And would like to run a contrast on the impactfact which has three levels.

I have tried setting it up using the following code:


contrasts(impactfact)<-cbind(c(-1,0,1),c(0,-1,1))
contrasts(impactfact)

But I am not sure what to do next can anyone help at all?

Thanks

Emma



----------------------
Emma Stone
Postgraduate Researcher
Bat Ecology and Bioacoustics Lab
& Mammal Research Unit
School of Biological Sciences,
University of Bristol, Woodland Road,
Bristol, BS8 1UG
Email: emma.stone at bristol.ac.uk