Dear list,

I performed an experiment along two rivers. In this experiment I used two
treatments, one called "blocked river" (Bl) and another one called "opened
river" (Op) and collected terrestrial vegetation-dwelling arthropods just
beside each opened and blocked treatments in order to test the possible
effect of emerging aquatic arthropods on terrestrial organisms. Each
treatment is 50 meters apart.

- Independent variable: two treatments (Op and Bl)
- Dependent variable: terrestrial arthropods (richness and biomass)

I think the data within each river isn't independent. Thus, I think I have
correlated errors within river.

I've read the chapter 5 of Pinheiro & Bates and I think that the functions
lme and ACF can be used to understand and test my correlated structure.

However, I'm new in lme and I have no clue how to model my data.

Maybe:

model1 <- lme (richness ~treatment|river)

I appreciate any feedback!

Thank you very much,

Thiago.


-- 
Thiago Gonçalves-Souza, Ms.
Universidade Estadual Paulista (UNESP)
Departamento de Zoologia e Botânica
Programa de Pós-Graduação em Biologia Animal (Doutorado)
E-mail alternativo: thiagoaracno@gmail.com
Home page:<http://www.wix.com/thiagocalvesouza/tg-s>

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