Exploratory data analysis before pefrorming Canonical Correspondence Analysis (CCA)

I want to perform CCA, but I read that,

remember that observations (for example, species abundances) have to present unimodal distributions along gradients (for example, environmental variables). Note that if observations are, instead, linearly related to gradients, we have to use a Canonical Correlation Analysis (CANCOR) or Redundancy Analysis (RDA) instead of a Canonical Correspondence Analysis (CCA).
Source: R Functions: Canonical Correspondence Analysis: CCA and Partial CCA

Which exploratory data analysis I can carry out (preferably in R) to be sure that my data are suitable for CCA?

• Yes, thanks. I've slightly modified it. It's entirely statistical question, but because i'm stick with certain language, the R solution would be more useful just for me. Jul 26, 2019 at 17:25