Complex sentence: Its reintroduction from northern Mexico would be a necessary step to recreate the soil humidity present in the Pleistocene, which would support grassland and extant shrubland and provide the habitat required for the herbivores set for reintroduction.
Split into simpler sentences: Its reintroduction from northern Mexico will prove to be a vital step in order to recreate the soils humidity present in the Pleistocene in order to support grassland and extant shrubland. This is necessary in order to provide the habitat required for the herbivores set for reintroduction.