[R-sig-ME] mixed model?

[Joaquín Aldabe]

Thankyou very much Evan. I´ll try that!
Cheers,
Joaquín.

2017-05-02 14:17 GMT-03:00 Evan Palmer-Young <ecp52 at cornell.edu>:

> Joaquin,
> It looks like you could use Year and Field as random effects, since there
> might be variation in bird abundance across years, and similarly, variation
> across fields.
>
> So in this case your model is
> Birdmodel<- glmer(Presence~ GrassHeight * ForestCover + (1|Year) +
> (1|Field), data=BirdData, family =                  "binomial")
>
> Alternatively you could use Year as a fixed effect, if you are interested
> in particular years.
> Another option is to include interaction terms as random effects, eg
> (1|Field:GrassHeight), to allow the effect of GrassHeight to vary across
> fields.
>
>
> On Fri, Apr 28, 2017 at 9:32 AM, Joaquín Aldabe <joaquin.aldabe at gmail.com>
> wrote:
>
>> Dear all, I'm analysing bird presence/absence in 16 grassland fields over
>> 4
>> seasons (different years) and want to know the effect of grass height and
>> forest cover on presence/absence of the species. Grass height varied among
>> season but not forest cover in each field. So we have a spatial dimension
>> and a time dimension. I tried a binomial glm but wonder if I should use
>> generalized linear mixed models with field identity as the random as I
>> have
>> repeated measures (bird counts) in each field.
>>
>> I appreciate your opinion.
>>
>> Thanks in advanced,
>>
>> Joaquin Aldabe.
>>
>> --
>> *Joaquín Aldabe*
>>
>> *Grupo Biodiversidad, Ambiente y Sociedad*
>> Centro Universitario de la Región Este, Universidad de la República
>> Ruta 15 (y Ruta 9), Km 28.500, Departamento de Rocha
>>
>> *Departamento de Conservación*
>> Aves Uruguay
>> BirdLife International
>> Canelones 1164, Montevideo
>>
>> https://sites.google.com/site/joaquin.aldabe
>> <https://sites.google.com/site/perfilprofesionaljoaquinaldabe>
>>
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>>
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>
>
>
>
> --
> Evan Palmer-Young
> PhD candidate
> Department of Biology
> 221 Morrill Science Center
> 611 North Pleasant St
> Amherst MA 01003
> https://scholar.google.com/citations?user=VGvOypoAAAAJ&hl=en
> https://sites.google.com/a/cornell.edu/evan-palmer-young/
> epalmery at cns.umass.edu
> ecp52 at cornell.edu
>



-- 
*Joaquín Aldabe*

*Grupo Biodiversidad, Ambiente y Sociedad*
Centro Universitario de la Región Este, Universidad de la República
Ruta 15 (y Ruta 9), Km 28.500, Departamento de Rocha

*Departamento de Conservación*
Aves Uruguay
BirdLife International
Canelones 1164, Montevideo

https://sites.google.com/site/joaquin.aldabe
<https://sites.google.com/site/perfilprofesionaljoaquinaldabe>

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