It is postulated by Quaternary paleoecologists that the glacial plains of the Pleistocene had a more varied vegetative cover than any plains environment which exist on the continents of the Earth today.
With the close of the last glaciation, precipitation patterns changed, bringing increased amounts of moisture to Northern latitudes. While glaciation lasted, there was a longer more variable growing season, which allowed for the co-existence of plant species that would today no longer be found together in the same area. This may have been caused in part by larger seasonal and intra-seasonal variations in local climates, which would give no particular species of plant a particular advantage over any other species. With this highly varied food source present, mammoths and other large herbivores were less susceptible to food loss and starvation, and were assured a steady food source during the entire year.
