[R] Envfit, inconsistant result?

[rodrock]

Hi R-experts,

I am using the envfit function over an ordination of floristic data.

The problem is that every time that I run it changes the results. Sometimes
dramatically, selecting variables that the first time were not significant.
I do not get what could be the problem or if is normal given the
permutations are different.

# the NMDS ordination

gap_flor_NMDS_chord <- metaMDS(gaps_flor, distance = "euclid", k = 2, trymax
= 20, autotransform =TRUE,
noshare = 0.1, wascores = TRUE, expand = TRUE, trace = 1,
plot = FALSE, old.wa = FALSE, zerodist = "add")

# the  environmental variables to use with enfit

explain1<- site[c("Tipo", "Gap.size", "Gap diameter (m)", "Size.cat",
"altitud", "Slope (%)", 
"Exp.deg", "form","formcont", "largo_medio_gmak_m", "Dom.Hight",
"d_m_gapmak_cm", "Cat_edad", 
 "uprooted_perc", "Snapped gap maker (%)", "stand_dead_perc",
"controlled_perc", 
 "nodet_orig_gmkr_perc",  "Total_borde", "PACL_diff_warm045",
  "rock", "musg_hep", "mantillo", "sm", "tronco_tot", "Time.ctr",
"mf_gmk_perc",
  "fm_gmk", "dc_gmk_perc", "be_gmk_perc", "ach_gmk_perc",
"nodet_spp_gmkr_perc",
 "Myrceugenia as border tree (%)", "Fm_borde.", "Dc_borde.", "Be_borde.",
"Rv_borde.", 
 "Aristotelia as border tree (%)")]   

# the  Envfit calculation
exp_flor1 <- envfit(gap_flor_NMDS_chord, explain1, permu = 999, na.rm=T)       


Thanks a lot for your help, comments and input!


-----
Rodrigo Vargas G.
-----------------------------------------
Silviculture Institute
Freiburg University

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