I would argue that you can't point to a single source like that in ecology. Grasslands are the way they are due to draught as well. They have dry periods, and

I would argue that you can't point to a single source like that in ecology. Grasslands are the way they are due to draught as well. They have dry periods, and during these they catch on fire and the whole thing burns down. > "A grassland can become either a desert or a forest if conditions like temperature, amount of rainfall, how often fires occur and how many herbivores live in these areas change. As more and more trees grow in a grassland, it is sometimes called a savanna." https://askabiologist.asu.edu/explore/grassland#:~:text=Forest%20and%20grassland%20often%20border,grass%20will%20rapidly%20take%20over https://askabiologist.asu.edu/explore/grassland#:~:text=Fore....