Synthesising 35 years of invasive non-native species research

The growing focus on the threat of invasive non-native species (INNS) in international biodiversity targets highlights a need for targeted research to support effective understanding, legislation, and management. However, the publishing landscape of invasion biology is complex and expanding rapidly, making consolidation of information increasingly challenging. To identify the major research themes in the INNS literature and to understand how these have changed over the last 35 years, we applied a topic modelling approach. We analysed approximately 10,000 peer-reviewed article abstracts to identify 50 key topics being discussed in the literature. We also quantified how publications on these topics changed over time and how commonly different topics interacted within articles as a measure of their connectedness. Topics covering Population genetics, Policy, First records and Insect biocontrol were the most frequent. Topics were grouped into broad themes, with the largest theme related to Ecosystems, followed by Monitoring, then Management and decision-making. Significant overrepresentation for particular geographical regions and taxa in the literature were apparent. Considering relative changes through time, the most prevalent topics in each decade reflected policy influences, and technological developments. When assessing the degree of connectedness- Policy, Population Genetics and Management Strategies showed low levels of co-occurrence with other topics. This is of particular concern for topics focussed on Policy and Management Strategy as it suggests a weakness at the science-policy interface around accessing and exchanging of evidence. If progress towards future global targets is to be made, we argue that more interdisciplinary research must be encouraged, in particular to better incorporate policy and management considerations into the wider research landscape.