I am not sure which model I might start using for the ecological modeling subject. In any case I wanted to ask which system to secure for myself, mac or windows? or maybe linux?
While I am at heart a Linux zealot, Windows is probably more flexible in that almost anything worth using open source wise can be targeted to Windows. As for system A is better than system B arguments, they are all bad if used poorly. I would identify packages you are interested in using and see how many of them are available for each platform and base your decision on that.
For ecological modeling I would recommend using R in Linux (ideally within RStudio) as it offers a wealth of packages (e.g., raster, RStoolbox, biomod2, maxnet, virtualspecies, etc.) and functions relevant/helpful to the subject. If you also familiarize yourself with QGIS (versions 3.5 onwards) you will have a hard time finding anything relevant you cannot do on your machine that can be done in Windows/Mac — except writing docx files maybe.
Personally, I would always go for Linux as it rarely ever truely crashes.