Prioritization of Invasive Alien Species With Potential to Threaten Agriculture And Biodiversity in Kenya Through Horizon Scanning

Abstract Invasive alien species (IAS) rank among the most significant drivers of species extinction and ecosystem degradation, causing significant impacts on ecosystem services, human well-being and socio-economic development. Recent invasions have spread rapidly in Africa due to porous borders constraining maintenance of border biosecurity. Countries also lack adequate information about potential invasions and have limited capacity to reduce risk of invasions. Horizon scanning prioritises the risks of potential IAS through rapid assessments of likelihood of their entry and establishment and their potential socio-economic and environmental impacts. This approach was used to identify and assess risks of 120 potential IAS (70 arthropods, 41 pathogens and 9 nematodes) to Kenya. The likely pathway of arrival for assessed species was mainly as contaminants of commodities, but some could most likely enter as stowaways. All species were scored for likelihood of entry, likelihood of establishment, potential socio-economic impact, and potential environmental impact on a 5-point scale. These individual scores were combined to rank the species according to their overall potential risk for the country. Confidence in individual and overall scores was recorded on a 3-point scale. For the highest-risk species, options for risk mitigation were suggested, including full pest risk analysis, surveillance for early detection, specific surveys for species not officially recorded but whose presence is suspected, and contingency planning. By prioritising risks, this approach can guide resource allocations to interventions that are most likely to reduce risk. It is appropriate for use by National Plant Protection Organisations and other relevant stakeholders in sub-Saharan Africa.