| Summary: | Across the globe, invasive non-native species (INNS) are a major ecological and economic problem with freshwater environments particularly susceptible to their impacts. Preventing their introduction and spread is considered the most environmentally desirable and cost-effective form of management by the Convention on Biological Diversity, and is advocated in new EU INNS legislation which comes into force in 2015. Biosecurity – a term describing actions taken to prevent the introduction and spread of unwanted organisms – is central to this preventative approach. This PhD combines ecological and social research to identify human-mediated pathways for the spread of INNS in freshwater environments; to examine the effectiveness of biosecurity measures; and to identify how biosecurity awareness and compliance could be improved. Initial questionnaire research revealed that recreational water users in the UK are potential vectors for INNS due to their movement patterns and low biosecurity compliance. A survival experiment showed that many aquatic INNS threatening the UK can survive in damp conditions for 16 days but demonstrated that hot water (45˚C, 15 mins) is an effective biosecurity control measure, causing 99% mortality in many high risk INNS within 1 hour. As a result of a long-term biosecurity campaign, New Zealand water users had high biosecurity awareness and compliance compared to the UK. The development of regional partnerships and the support of national legislation were key components of the country’s streamlined approach to biosecurity. Invasive non-native crayfish had a significantly lower diversity and prevalence of parasites than native crayfish in the UK, supporting the concept of enemy release. Finally, a global meta-analysis revealed that recreational activities also act as vectors for the introduction of INNS in terrestrial and marine environments and require biosecurity measures of a similar magnitude. The results provide an evidence base from which to develop freshwater biosecurity strategies in the UK and wider Europe.
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