Why do savannas differ? Savannas have developed in an uneasy equilibrium over time with varying pressures, leading to an amalgamation of landscape patterns. They are also the product of disturbance and conversion from other ecosystems, especially tropical forests. Each continent has developed a unique collection of plants and animals with a particular environmental evolution and history of human occupation. As a result they have followed different evolutionary pathways leading to distinct landscapes and particular challenges for their futures. ‘Savanna vegetation’ considers the primary productivity of plants, the vegetation structure, and species richness across savannas in Africa, tropical America (including Brazil, Colombia, and Venezuela), Central America and the Caribbean, and Australasia.