I have a number of rasters of environmental data (~10) which may be important predictors for modelling species presence and abundance at ~10 different locations.
I would like to know which of the rasters are important in explaining the variance in observed results. Is it appropriate to look for principal components of the rasters? Is this done across the entire extent, or only with respect to my observed sites? Any reference on this would be appreciated.
EDIT: It turns out that PCs are not useful in this case. Even though two rasters may have very large correlation across the landscape, if they are different at the narrow range of sites occupied by the modelled species, this is what really matters.