I have four sites:
Treatment_1 and Control_1 of experiment 1 (8 plots in total)
Treatment_2 & Control_2 of experiment 2 (8 plots in total)
I ran an RDA for each experiment separately to compare treatment and control.
The RDAs both show nicely that there are two separate groups for control and treatment, in each experiment.
Treatment 1 appears much further from control 1 than treatment 2 is from control 2-
My Question- Can I COMPARE the two RDAs?
How can I show if treatment 1 had a stronger effect than treatment 2, (either with or without a significance test)?
Can I just calculate the distance on RDA1, or euclidean distance between the centroids of control and treatment, and compare the two experiments?
vegdist function gives me a matrix of distances from each plot to all others.. should I just compare the average distances between all control plots and treatment plots in the two experiments?
Is there a simpler way/ function in vegan to do this?