Freshwater Navigation Is Linked to Non‐Native Species Distributions Across Spatial Scales

Aim Invasive species are among the most important drivers of native species declines, and cause serious economic and ecological costs. Globally, Europe is a hotspot for freshwater non‐native species, especially among macroinvertebrates and fish, and inland navigation is thought to be a major driver of their spread. However, the degree to which different aspects of navigation (i.e., ship traffic vs. infrastructures) contribute to non‐native species spread, establishment and distribution has not yet been quantified. Our study set out to determine the role that navigation plays in the distribution of Western European freshwater established non‐native species, and which aspects of navigation are most responsible. Additionally, we aimed to identify the spatial scale at which these navigation pressures operate, and what ecological characteristics may influence species' response to navigation. Location Europe. Methods We extracted data from the Global Biodiversity Information Facility (GBIF) to identify occurrences of established non‐native species in Europe from the past 30 years. Using over 500,000 occurrences, we mapped the coverage of over 250 established non‐native species and paired this with pan‐European data on inland ship traffic, navigation infrastructure and environmental data. Results We found that the greatest predictor of non‐native species richness and occurrences was the presence of a shipping canal in the subcatchment. This held true for both fish and macroinvertebrates at fine and large spatial scales. Temperature was also an important predictor of non‐native species distribution. We found these positive associations to be strongest for generalist fish species, molluscs and crustaceans. Main Conclusions Freshwater navigation, especially canals, is an important vector for non‐native species establishment, and highlights the need for frequent monitoring and mitigation. Given that increased temperatures are associated with establishment success, climate change may also play an increased role in non‐native species dispersal.