Complex sentence: The Plateau has also a rich fauna, among whom can be found specimens of the Nile crocodile, once existing through all the Sahara and now surviving only in a few pools in river canyons in the area, where they are menaced with extinction.
Split into simpler sentences: The Plateau has also a rich fauna, among whom can be found specimens of the Nile crocodile, once existing through all the Sahara. They survive only in a few pools in river canyons in the area, where they are menaced with extinction.