Data from: Assessing patterns in introduction pathways of alien species by linking major invasion databases

1. Preventing the arrival of invasive alien species (IAS) is a major priority in managing biological invasions. However, information on introduction pathways is currently scattered across many databases that often use different categorisations to describe similar pathways. This hampers the identification and prioritisation of pathways in order to meet the main targets of recent environmental policies. 2. Therefore, we integrate pathway information from two major IAS databases, IUCN's Global Invasive Species Database (GISD) and the DAISIE European Invasive Alien Species Gateway, applying the new standard categorisation scheme recently adopted by the Convention on Biological Diversity (CBD). We describe the process of mapping pathways from the individual databases to the CBD scheme and provide, for the first time, detailed descriptions of the standard pathway categories. The combined dataset includes pathway information for 8323 species across major taxonomic groups (plants, vertebrates, invertebrates, algae, fungi, other) and environments (terrestrial, freshwater, marine). 3. We analyse the data for major patterns in the introduction pathways, highlighting that the specific research question and context determines whether the combined or an individual dataset is the better information source for such analyses. While the combined dataset provides an improved basis for direction-setting in invasion management policies on the global level, individual datasets often better reflect regional idiosyncrasies. The combined dataset should thus be considered in addition to, rather than replacing, existing individual datasets. 4. Pathway patterns derived from the combined and individual datasets show that the intentional pathways 'Escape' and 'Release' are most important for plants and vertebrates, while for invertebrates, algae, fungi and micro-organisms unintentional transport pathways prevail. Differences in pathway proportions among marine, freshwater and terrestrial environments are much less pronounced. The results also show that IAS with highest impacts in Europe are on average associated with a greater number of pathways than other alien species and are more frequently introduced both intentionally and unintentionally. 5. Synthesis and applications. Linking databases on invasive alien species by harmonising and consolidating their pathway information is essential to turn dispersed data into useful knowledge. The standard pathway categorisation scheme recently adopted by the Convention on Biological Diversity may be crucial to facilitate this process. Our study demonstrates the value of integrating major invasion databases to help managers and policymakers reach robust conclusions about patterns in introduction pathways and thus aid effective prevention and prioritisation in invasion management.Introduction pathways of alien speciesThe data file INTRODUCTION_PATHWAYS.xls contains information for 8323 introduced species regarding introduction pathways, taxonomic group (plants, vertebrates, invertebrates, algae, fungi, other), inhabited environment (terrestrial, freshwater, marine) and listing status on three different lists of worst invasive alien species. Pathway data were retrieved from the Invasive Alien Species Pathway Management Resource (IASPMR, www.pathway-toolbox.auckland.ac.nz), including all pathway information contained in the Global Invasive Species Database (GISD, www.iucngisd.org), and from DAISIE European Invasive Alien Species Gateway (www.europe-aliens.org). The README file provides basic descriptions of the variables in the data file. For full details on data handling and pathway categorisation see Saul et al. (2016, J Appl Ecol).INTRODUCTION_PATHWAYS.xl