Woody invasive alien species are among the world’s worst invaders, significantly affecting ecosystem services, increasing the cost of farming and reducing access to land. Prosopis juliflora (“prosopis”), a spiny shrub or tree, was introduced from its native Latin America into Eastern Africa to reduce dust and sandstorms and provide wood and fodder for livestock, but it has spread from the original areas of introduction and invaded large areas of land, thereby replacing grazing and arable land with impenetrable thickets.