Large predators shape the plant life of the African savannah, and no doubt everywhere else too; As Scientific American reports:
The impala – an African antelope – eats grasses and trees and is itself eaten by wild dogs and leopards. Impala often munch on a tree called the acacia. Some acacia have thorns, and some don’t. The researchers found that the impala – perhaps not surprisingly – prefer thorn-free acacia. Also, the animals avoid woody areas where predators are more likely to hide. And as a result, the thorn-free, vulnerable acacia are more plentiful in woody areas with plenty of predators. But the thorny acacia are more numerous on the open savannah, where they need to defend themselves. The study is in the journal Science.