[R-sig-eco] Adonis model help

[Josie Galbraith]

Hi all,

I'm new to community data analysis in R and was hoping to get some feedback
on my intended approach using adonis.

The primary aim is to test the effect of treatment group (FOOD: F or N) on
community assemblage.  I have repeated measures data so I have included
SITE ID as a random factor and constrained permutations to within sites
(using the ‘strata’ argument).  I want to include survey month (categorical
factor) as a fixed effect in the models to look at temporal variability,
and also want to include 2 other variables as random factors: vegetation
and background feeding level. (Structure of data given below).

Is the following appropriate?

adonis(Dmatrx ~TREAT*MONTH + VEG + BKF + SITE, data=Dmetadata,
strata=Dmetadata$SITE, permutations = 999)

Thanks in advance,
Josie


'data.frame':    413 obs. of  6 variables:
 $ MONTH  : Factor w/ 18 levels "5","6","7","8",..: 1 1 1 1 1 1 1 1 1 1 ...
 $ SITE   : Factor w/ 23 levels "ABER","BAYS",..: 1 9 22 19 6 14 15 4 23 18
...
 $ FOOD   : Factor w/ 2 levels "F","N": 2 1 1 2 2 1 2 1 1 2 ...
 $ VEG    : Factor w/ 3 levels "1","2","3": 3 1 2 1 2 1 1 2 2 3 ...
 $ BKF    : Factor w/ 3 levels "High","Low","Med": 3 3 3 3 1 3 3 1 1 3 ...


-- 
*Josie Galbraith*
PhD student
*University of Auckland *
Joint Graduate School in Biodiversity and Biosecurity ● School of
Biological Sciences ● Tamaki Campus ● Private Bag 92019 ● Auckland 1142* ●
P:* 09-373 7599 ext. 83132

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