Data on pathways of introduction and spread of invasive alien species of union and national concern

The dataset was used to analyze the pathways of introduction and spread to and within Sweden for 101 invasive alien species, of which 88 are of Union concern (included in the European Union list of invasive alien species) and 13 are of national interest (selected by the Swedish Environmental Protection Agency). The geographical area being covered is Sweden's land territory, territorial water and economic zone. The dataset contains actual and probable pathways that have been identified for each of the species. The information was collected from existing risk assessments in the European Union for species of Union concern and national risk analyses from Belgium, Denmark, Norway and Sweden. We have also consulted various databases, including Nobanis (European Network on Invasive Alien Species), CABI (Centre for Agriculture and Biosciences International), DAISIE (Delivering Alien Invasive Species Inventories for Europe), GISD (Global Invasive Species Database), EPPO (European and Mediterranean Plant Protection Organization), EASIN (European Alien Species Information Network) and the SLU Species Information Centre. We have followed the CBD (Convention on Biological Diversity) pathways classification framework. This framework includes a total of 47 pathways divided into six main categories; Release in nature, Escape from confinement, Transport - contaminant, Transport - stowaway, Corridor, and Unaided. All but the first are unintentional pathways. The pathways that we have identified are not necessarily limited to those previously identified in various risk analyses or databases. We have identified all potential pathways based on whether the mechanism for transport is in place. The analysis was performed for three different starting points of pathways; in a foreign country, in contained or confined use in Sweden, and in Swedish nature. The first two starting points may result in an introduction of an alien species into Swedish nature, whereas the third involves pathways of spread within Swedish nature. Pathways of deliberate introduction for contained use in Sweden, such as import, are not included in the analysis as we assume that these will not be permitted. In the process of identification of priority pathways, the presence of each species at a starting point was considered. For starting points abroad, the species have always been considered as present. Among the 101 species, 56 occur in contained use in Sweden (including e.g. botanical and zoological gardens, private aquaria and gardens, aquaculture, research institutions and fur farms), and 40 species have been judged as being present in Swedish nature. Given the presence of the species at a starting point, their ability to use the different pathways and to become established in Swedish nature and cause damage to Swedish nature was considered. The invasion potential and ecological effects of invasive alien species have been estimated in the risk analyses performed by the SLU Swedish Species Information Centre. The invasion potential is based on the expected time to extinction in Sweden, the geographical expansion speed, and ability of the species to colonize natural environments, whereas the estimate of ecological effects is based on the ecological, genetic and epidemiological effects on native species and natural environments. Seventeen species are not yet risk analyzed by the SLU Swedish Species Information Centre. The invasion potential and ecological effects of these species were estimated using available information. Several analyses were performed to identify pathways in the current state and for two hypothetical scenarios in the future. The hypothetical scenarios were based on assumptions of increasing private trade in and keeping of listed invasive alien species, and increased possibilities for species to become established in Swedish nature due to climate change. For more information, please see the Swedish description above.