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This chapter reviews the impacts of Prosopis invasions on biodiversity and ecosystem services in eastern Africa and addresses the potential for their restoration following control. Invasion by Prosopis trees affects the composition, structure and functioning of invaded ecosystems because the trees are superior competitors for water, light and nutrients. Prosopis trees form impenetrable stands that alter habitats and exclude wildlife, and they cause harm by being toxic and causing physical injury to animals and people. Studies in eastern and southern Africa have demonstrated that invasions reduce the species richness of native tree, shrub and grass communities, with knock-on impacts on native bird, mammal and invertebrate communities. Invasion brings about dramatic changes in structure, from ecosystems with scattered trees and abundant grasses to closed-canopy, impenetrable stands of trees with little or no grass below them. Ecosystem functioning and the ability of ecosystems to deliver services such as livestock production, water supply, traditional medicinal remedies and carbon storage are also affected, both directly and indirectly. Control of invasions can restore some of these services, and such action is justified because of the positive returns on investment in control. Such control would achieve more if the diverse and productive herbaceous communities that are important for ecosystem functioning could also be restored. Indigenous peoples and local communities are generally aware of the impacts of invasions on biodiversity, although a smaller minority are either unaware or their perceptions tend to be positive due to perceived benefits. The implications of these findings are that governments, aid agencies and communities would benefit from investing in control to protect biodiversity and ecosystem services by preventing the further spread of invasive Prosopis trees, implementing targeted control efforts where the species has become established, and actively restoring biodiversity to areas where the invasive trees have been brought under control.