I'm working with a matrix of community count data. We collected both continuous and categorical environmental information.I would like to use adonis2 (R package vegan) to apply permutational analysis of variance to see if community structure can be explained by environmental variables. I've used adonis2 before to check for overall compositional differences between categories, and I'm quite confident that I understand the way PERMANOVA works, as in
distance_matrix ~ grouping_variable
What I cannot wrap my head around is the way adonis handles continuous explanatory variables, as in distance_matrix ~ continuous_variable (say e.g. height)
Judging from the output it creates, it looks like it's treated as categorical but with many different levels. I'm not sure if this addresses my research question appropriately. Could someone please help me out here?