[R-sig-eco] Resource selection- correlation between variables

[Teresa Oliveira]

Dear all,

I have a doubt regarding correlation between variables, and I would like to
hear your opinion on this.

Background:
I am working with telemetry data of a single species, collected by several
researchers, from five study areas. I aim to analyse resource selection
(with resource selection functions, RSF), applying Design II (individual
locations (used resource units) against study area (available resource
units)) and Design III (individual locations (used resource units) against
home range area (available resource units)). I have 13 variables in total:
10 binary variables (land cover characteristics) and 3 continuous variables
(roughness, distance to water and distance to human settlements).

I want to construct models for each study area and also a global model
including all five study areas, because I want to see if it is possible to
apply a global model for all areas or if they are very different from each
other. I'm planning to use a sampling with replacement method to understand
the effect of each area on the global model.

Question:
Before starting with RSF, I want to check if my variables are independent,
and I'm not quite sure how I am supposed to conduct the analyses. Should I
use all data (from all individuals in all study areas) to test correlation
between all variables? Or should I conduct different analyses for each
study area (or even each individual)?

Does anyone have any suggestions?

Thank you very much in advance,
Teresa

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