[R] GLM with nested design

[Giovanni Bacaro]

Dear list members,
I'd like to perform a glm analysis with a hierarchically nested design. In
particular,
I have one fixed factor ("Land Use Classes") with three levels and a
random factor ("quadrat") nested within Land Use Classes with different
levels per classes (class artificial = 1 quadrat; class crops = 67
quadrats; and class seminatural = 30 quadrats).
I have four replicates per each quadrats (response variable = species
richness per plot)

Here some question about:
1) could I analize these data using the class "artificial" (i.e. I have
only 1 level)?

2) using R I'd like perfor a glm analysis considering my response variable
(count of species) with a Poisson distribution. How can I develop my model
considering the nested nature of my design? I'm sorry but I don't know the
right package to use.

3) for the Anova analysis I'd like use a post-hoc comparison between
pairwise classes. What is the right procedure to do this? Is this analysis
performed in R?

Thanks
Giovanni

-- 
Dr. Giovanni Bacaro
Università degli Studi di Siena
Dipartimento di Scienze Ambientali "G. Sarfatti"
Via P.A. Mattioli 4 53100 Siena
tel. 0577 235408
email: bacaro a unisi.it