The African continent has a wide variety of habitat types, but savanna ecosystems cover roughly half. And where there is savanna, there is fire. “It's an important part of the ecology of the system,” says University of Liverpool ecologist James R. Probert. Burning allows grasses to dominate by keeping taller shrubs and thorn bushes from encroaching on the landscape. Loss of grasses could push out species such as wildebeest, which are famous for their spectacular annual migration.