OK, it seems I misunderstood because I don't know much about grass. It seems there was some grass there a long time ago, but there is also a lot of "alien grass" that was introduced to the Cape region by humans. The alien grass is considered invasive and outcompetes the natural vegetation there which is called fynbos.
Really? It doesn't seem to be true: http://rstb.royalsocietypublishing.org/content/371/1696/2015... talks about grasslands in South Africa 1-2 million years ago, well before humans existed.
OK, it seems I misunderstood because I don't know much about grass. It seems there was some grass there a long time ago, but there is also a lot of "alien grass" that was introduced to the Cape region by humans. The alien grass is considered invasive and outcompetes the natural vegetation there which is called fynbos.