rda - different result from varpart and RsquareAdj

Question

I'm getting different results from varpart and RsquareAdj

> (allel_freq.varpar<-varpart(allel_freq.h,env.PCoA,PCNM.red))
Partition of variation in RDA

Call: varpart(Y = allel_freq.h, X = env.PCoA, PCNM.red)

Explanatory tables:
X1:  env.PCoA
X2:  PCNM.red 

No. of explanatory tables: 2 
Total variation (SS): 0.0017369 
        Variance: 0.00017369 
No. of observations: 11 

 Partition table:
 Df R.squared Adj.R.squared Testable
[a+b] = X1            2   0.23618       0.04522     TRUE
[b+c] = X2            2   0.54147       0.42683     TRUE
[a+b+c] = X1+X2       4   0.65547       0.42578     TRUE
Individual fractions                                    
[a] = X1|X2           2                -0.00106     TRUE
[b]                   0                 0.04628    FALSE
[c] = X2|X1           2                 0.38056     TRUE
[d] = Residuals                         0.57422    FALSE

in "varpart",Unique effect of env.PCoA is -0.00106,but when I use "RsquareAdj", I got different adjusted R-square(-0.2266707). strange.

> rda.envspe<-rda(allel_freq.h,env.PCoA,cbind(PCNM.red))
> RsquareAdj(rda.envspe)
$r.squared
[1] 0.1139976

$adj.r.squared
[1] -0.2266707