changes in latitude changes in attitude

Reference - http://www.sciencenews.org/view/generic/id/335179/title/Trees_have_a_tipping_point

Summary- Two different ecosystems; grassland or forest. Since the dramatic changes in temperatures, we soon may not know the difference. Scientists have made "resilience maps" these maps show what parts of the world are likely going to tip from plains to forest or vice versa. Farmers in the Amazon may use this maps to see how their living arrangements may be in the near future. For example, there is a tall grass prairie across Illinois all the way to Indiana, the grassland was kept grassy by fire and grazing management. All else, it would revert to a forest.
Critique- Well if we don't have a difference between grassland and prairie, then there would be no different ecosystems throughout the world. Here, there's a desert and if we drive two hours there's a forest. If there was only one ecosystem, we wouldn't have a world of different species to explore.
Impact- There would be a lot of impact on the species of these different ecosystems. If a forest turned into a grassland, what would giraffes eat. Uh oh.