Unfortunately the image doesn't make any sense.
Cows exist on earth because of their symbioses with man.
If man stops eating cows, than the cows will cease existing.
Further, if you were to draw it correctly, the top half should be brown, not green. Just like the bottom half was drawn in red, one must not delude themselves into thinking that vegetarian diets do not have consequences on the land.
Producing food baring plants results in greenery. Eating food from food baring plants tends to involve eating seeds, which when pooped naturally, will result in more plants and more greenery. Without this basic principle, there would not be mammals.
What evidence is there that cows exist because of humans? As far as I am aware they are descendents of wild Ox and:
Read more: Difference Between Ox and Cow | Difference Between http://www.differencebetween.net/science/nature/difference-between-ox-and-cow/#ixzz5UVke3ZGH
They are many 1000s of years old at least.
Without humans there would be less cows, yes - and less suffering as a result.