Context Invasive alien species are an important driver of biodiversity loss. Policy responses are developed to address this threat and need to be based on the best available data, including information from alien species registries and occurrence data. The Tracking Invasive Alien Species ( TrIAS ) project implemented a indicator workflow based on FAIR principles to feed policy relevant indicators for biological invasions in Belgium from openly published checklist and occurrence data on GBIF. Description This dataset contains the outputs of the pipeline that prioritizes alien species based on their emergence status. This prioritization is built upon the information contained in: The Global Register of Introduced and Invasive Species - Belgium (GRIIS Belgium) which is published by the IUCN Invasive Species Specialist Group (ISSG) based on the unified checklist of alien species in Belgium which was created by TrIAS in support of research and policy using an open and reproducible workflow. The species occurrence cube for non-native taxa in Belgium . We provide two different prioritization strategies:hierarchical ranking and point strategy. We do the prioritzation for both Belgium and its three regions separately: Flanders, Wallonia and Brussels. Only the prioritization for Belgium takes into account the emergence status (number of occurrences and observed occupancy) in Natura2000 protected areas. Hierarchical ranking The ranking is based on the highest emerging status. The following priority rules are applied, in order of importance: The more recent, the higher priority is. Emerging statuses in protected areas are more important than the ones defined over entire Belgium. Emerging statuses from occupancy are more important than the ones from occurrences. The higher average minimal guaranteed growth (#occs/year), the higher priority is. Points strategy The points strategy is based on applying gain factors to emerging statuses using the number of observations in 2020 in Belgium/region as reference (gain factor = 1). ...