Environmental DNA surveillance for invertebrate species: advantages and technical limitations to detect invasive crayfish Procambarus clarkii in freshwater ponds

1. The introduction of non-native species is a major threat to biodiversity. While eradication programs of well-established invaders are costly and hazardous for non-target species, the early detection of a non-native species at low density is critical for preventing biological invasions in recipient ecosystems. Recent studies reveal that environmental DNA (eDNA) is a powerful tool for detecting target species in aquatic ecosystems, but these studies focus mostly on fish and amphibians. 2. We examine the reliability of using eDNA to detect the presence of an invasive freshwater crustacean species, the red swamp crayfish Procambarus clarkii. Species-specific primers and probes were designed; their specificity was tested using in silico PCR simulations and against tissues of other crayfish species. Limits of detection and quantification were specified for the target DNA sequence by means of quantitative PCR amplifications on dilution series of known amount of P. clarkii DNA. 3. The method...