In the vegan package, I tried to make a ordination plot with species as objects and environmental variables as vectors. However the environmental variables are regarded as centroids instead of factors. Strangely each data frame cell is seen as an environmental factor, so I think the dataframe is not structured correctly. When I plot the ordination without environmental variables I don't get any problems.
summary(gutter.dca)
environfit = envfit(gutter.dca,gutterenv)
> head(environfit)
$vectors
NULL
$factors
Centroids:
DCA1 DCA2
vocht0,246435845 -0.2185 -1.0601
vocht0,249249249 0.1932 -1.1339
vocht0,251497006 0.0331 -2.0888
vocht0,264735265 -0.3353 -1.3403
vocht0,26911315 -0.0017 -0.9498
vocht0,272369715 -1.0733 0.0021
Species dataframe
head(gutter)
Acer.campestre Acer.pseudoplantanus Adoxa.moschatellina Aegopodium.podagraria Ajuga.reptans
Q1-1 0 0 5 0 0
Q1-2 0 70 15 20 0
Q1-3 0 15 0 0 0
Q1-4 0 3 0 0 0
Q2-1 0 3 0 0 0
Q2-2 1 0 0 0 0
Environmental variables dataframe
head(gutterenv)
vocht Ph.H2O ph.KCl mg.NO3.kg.soil mg.NH4.N.kg.soil litter.depth..cm.
1 0,26911315 7,41 6,686 2,811031105 4,674304351 7,5
2 0,246435845 7,225 6,349 2,567981088 6,735395066 6,5
3 0,264735265 7,001 6,491 2,336821354 8,400116244 5,1
4 0,325123153 6,732 5,444 2,518858082 7,684506342 8,25
5 0,446875 6,87 7,45 2,443686352 9,886923756 4
6 0,548476454 8,1 7,05 3,144954614 11,3179919 3