Have you considered using something like ruggedness or topographic heterogeneity as a layer? There's data for that.

Hi Rutger. I'm not sure this will help but the USGS has developed/is developing a global ecological land units/ecosystems map. The overall project is here.

https://www.usgs.gov/centers/gecsc/science/global-ecosystems?qt-science_center_objects=0#qt-science_center_objects

The Africa Data are here:

https://rmgsc.cr.usgs.gov/ecosystems/datadownload.shtml

I've always thought these data would be excellent for SDM work, but they seem to not have been found by the SDM community. The approach includes a layers called "land surface forms", which includes hills, escarpments, low mountains, smooth plains, etc. This might help you. There is also an arcgis viewer. This link may work.

https://www.arcgis.com/home/webmap/viewer.html?url=https%3A%2F%2Frmgsc.cr.usgs.gov%2Farcgis%2Frest%2Fservices%2FcontAF%2FMapServer&source=sd

Oops. I did not realize Abraham asked the original question! Abraham, I hope the data I mentioned helps you!

Hi Rutger A. Vos

Thank you very much for your answer, however would you mind to explain more on what is the layer contains?

Regards

Abraham

Hi Jay E Diffendorfer

I tried to open the link for Africa but it gives the message of 'The page cannot be displayed because an internal server error has occurred.'

So I did not get the access. Can you try to check the links if they are still working?

Regards

Abraham