Why is the savannah a fragile enviroment?

The savannah is a fragile environment is because it's sparesly populated, and the amount of nutrients there is very low. there are few trees and plants, few herbivors, and even less carnivores. there are not many water sources either, so savannahs are quite prone to droughts. a lack of nutrients added to lack of water = dehydration and starvation, killing off the weaker links fo the environment.