Hi,
As far as I know, habitat selection (RSF) is mainly applied by collecting habitat/environmental component susing SINGLE point. For example determining used, unused and available habitat for each SINGLE point. However, I am interested to know whether a grouping behavior (fission) select particular land cover and its environmental variables. So at least I have to define two closed individuals which mean TWO points. In this case, how I should define used habitat for those two individuals?
any help will be appreciated. Thanks!
Hi Muhammad,
You should look into Craiu et al. 2011 "Conditional logistic regression with longitudinal follow-up and individual-level random coefficients: a stable and efficient two-step estimation method". They modeled habitat selection for pairs of bison using an SSF framework conditional upon both step and group. The R package 'TwostepCLogit' is pretty intuitive when it comes to building models and is able to model both fixed and random effects.
Hi, I would strongly recommend checking out this article: Article Habitat and social factors shape individual decisions and em...
and perhaps reaching out to some of the authors. Cheers, Paul
Hi Muhammad In a RSF you are not necessarily analyzing point data. So if your study animals come together I assume they are quite close, you can define the used area using a buffer that encloses the group, and sample environmental variables using this buffer. This would be you used (1) data, the available sample (0) would be random or paired sample of areas using the same buffer size. When doing RSF type of analyses it is common to experiment with buffer size (scale) a little as we are unsure of the scale that different species may select habitat, so you may want to use a range of buffer sizes to sample the used and available locations.
Hi Steven, thanks for the suggestion. But in our case we use elephant as our studied species, which means it is not quite close. and sometimes we found two individuals are within range of fusion but they are on different habitat types, thus applying buffer is not so fit for my question.
In addition i also would like to know, when they are doing fission which means far. How do i analyze their selection.
Hi Muhammad yes in that case each individual would be a separate point or buffer. Maybe the best way of incorporating the fission fusion part is to have a 1 fission or 0 fusion variable for each observation. This can then be entered into the model as an interaction to understand if or how each habitat variable is related to grouping behavior, this may be easier than separating it into two analyses (Fis and Fus) until you find you need to. The random available points should be sampled from the surveyed study area, i.e. only where you have sampled. Unsure how you are collecting the data (GPS collar?) but you may also want to put individual ID in as a random effect. You should use a mixed effects model with a logit link function (logistic regression). There is a lot I don't know about your study and a lot to consider with RSFs to get them correct, hope this helps you make some progress. I have found some of the most helpful RSF papers are by Mark Boyce, Chris Johnson and Scott neilson, and their colleges.
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