Application of environmental DNA for monitoring and management of aquatic biological invasions: Emerging trends and advancements towards best practice

Emily Chen

The introduction and spread of Aquatic Invasive Species (AIS) threaten biodiversity worldwide, marine industries, and even human health. Once invasive species become successfully established in a new environment, eradication is difficult and costly, so early detection is key to management. To complement traditional surveying methods, there have been significant increases in rapid and non-invasive sampling approaches such as environmental DNA (eDNA). This study aims to compile and investigate trends in eDNA practices since their first implementation approximately a decade ago, including sampling techniques and subsequent processing protocols, with the intention to inform future directions of eDNA research. Data were extracted from existing literature using either specifies-specific or metabarcoding approaches, with 492 records from 192 studies ultimately used for reporting and analysis. The results indicated a need for increased research in understudied geographic regions (Asia, South America, and Africa) that can help close gaps in AIS connectivity knowledge. Differences were found in targeted taxonomic groups between freshwater and marine environments, which were driven by a focus on the most ecologically damaging or economically important taxa within each environment. This work revealed the importance for clearer guidelines in eDNA metadata collection to improve future experimental design and facilitate greater comparability across studies.