[R] Why do I get (not estimable) in this aov data

[Hedberg Peter]

Dear all.
I am trying to analyze my data with an anova, using aov, and the result looks like this

> my_data<-read.csv(file.choose(),header=T,dec=".",sep=";")
> attach(my_data)
> names(my_data)

 [1] "Site"           "Obstacle"       "Treatment"      "Dist_Obstacle"  "Dist_start"     "Transect"       "Mainplot"       "Obsplot"        "Species1"       "Species2"       "Species3"      
[12] "Species4"       "Species5"       "Species6"       "Species7"       "Species8"       "Species9"       "Species10"      "Species11"      "Species12"      "Species13"      "Species14"     
[23] "Species15"      "Species16"      "Species_change" "channge_index"  "Waterdata"      "litter"         "bare.soil"     
> aov_data<-aov(Species1~Site+Obstacle+Treatment+as.factor(Dist_Obstacle)+as.factor(Dist_start)+Transect+Mainplot+Obsplot)
> aov_data
Call:
   aov(formula = Species1 ~ Site + Obstacle + Treatment + as.factor(Dist_Obstacle) + 
    as.factor(Dist_start) + Transect + Mainplot + Obsplot)

Terms:
                     Site  Obstacle Treatment as.factor(Dist_Obstacle) as.factor(Dist_start)  Transect   Obsplot Residuals
Sum of Squares   2143.984   446.274   340.042                  736.073               173.707   800.270  4014.378 17238.625
Deg. of Freedom         2         1         1                        4                     3        10        60       271

Residual standard error: 7.97566 
27 out of 109 effects not estimable
Estimated effects may be unbalanced



My question is why do I get "effects not estimable", and "effects may be unbalanced). I have checked the data and it is balanced.

I have attached the data to the question and would be greatly thankful for any help in understanding the output.

Best regards,

Petter

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