[R-sig-eco] Compare 4 comunity by similarity index

[Marcelo]

Hello,

I have four communities (site) in my project, like this:

site          specie      quantity
1               A           100
1               B             1
1               C            23
1               D            56
2               A             0
2               B           110
2               C             3
2               D             6
3               A            10
3               B             1
3               C             2
3               D             1
4               A             2
4               B             1
4               C             3
4               D             0

How I could compare this four communities? I had calculated Shannon H'
index, but it is only intra community, not to compare inter communities. I
have read about quantitative Czekanowski index, but, it compare only two
communities.

Please, what I could calculate from my data to compare they?

Thank you very much.

Marcelo