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glmm question

1 message · Joaquín Aldabe

#
Hello, this is Joaqu?n Aldabe from Uruguay. I?m trying to model shorebird
counts (Buff breasted Sandpiper, BBSA) with glmm (using lme4 package),
using continuous variables (grass height, field area, forest cover) and one
factor variable (presence/absence of other shorebird species: American
Golden Plover, AMGP). I sampled 19 fields during three years in December.
I?m interested in identifying predictors correlated with BBSA counts. I
used Year as a random effect as I?m not interested in Year as a fix effect
and because fields were counted three times (pseudoreplication).

The model doesn?t converge, and the output showed that the factorial
variable has not a significant effect. This is weird as in every field I
observed the Buff breasted Sandpiper I also observed the other
species. When I take AMGP out, the model runs ok.

This is the model I?m trying to run:

mysub3.3<-glmer(BBSA~Grass_height+Field_area+Field_enclosure_700m+Grass_height*Field_enclosure_700m+fAMGP+(1|fYear),family="poisson",
data=mysub3.2)

continuous variables were scaled.

I can send de data frame if somebody is interested.

Thanks in advanced for helping me on my master thesis.

Cheers,

Joaqu?n.