Ecosystem engineer unleashed: Prosopis juliflora threatening ecosystem services?

The introduction of fast-growing plant species has been a strategy worldwide to combat problems arising from land degradation. Prosopis juliflora is an ecosystem engineer that was introduced to Ethiopia in the 1970s to address erosion problems but has subsequently become an important invader. This paper analyzes the spread of P. juliflora in Baadu, located in the middle Awash Basin of Ethiopia, qualitatively assesses its impacts on ecosystem services and identifies research needs and challenges for sustainable land management. The plant was introduced in 1983 around cotton farms in the case study region to provide erosion regulation. By the year 2013, P. juliflora had invaded 20,000 ha (40 % of wetlands). It partly invaded also the riverbanks and agricultural lands and is expanding into adjacent dryland areas. The negative impacts of this invasion are partially offset by provisioning of firewood and charcoal. However, the difficulties to control its rapid spread indicate that the threats it poses to ecosystem services, people’s livelihoods and lifestyles may exceed its benefits. We argue for an integrated research approach that considers both the services and disservices, as well as the social discourse among different groups of actors to appropriately address this issue and identify options for sustainable action.