Using Morphological and Molecular Genetic Approaches to Assess Stream Biodiversity and Prey Availability

The analysis of food webs and their dynamics is important for understanding aquatic ecosystem functions. A critical factor involved in constructing these food webs is developing techniques that efficiently and accurately determine dietary ranges and assess predator-prey relationships. Potential prey items of fish have traditionally used morphological identification of aquatic invertebrates, but the limited taxonomic database for all life stages of aquatic invertebrates makes this approach difficult to resolve to the species level. Recent DNA-based approaches have been developed and provide greater insight to biodiversity and species identification. For this study, we compared traditional morphological methods and metabarcoding techniques to rapidly and accurately assess stream biodiversity and ecological processes in streams from coastal and interior British Columbia, Canada. The metabarcoding approach was used for analysing environmental DNA (eDNA) from water samples and for analysing preservative ethanol from bulk benthic invertebrate samples collected by Surber sampling. These methods were analysed on an Ion Torrent platform and were dependent on obtaining DNA from the environmental samples. By combining DNA from alternative sources (water samples and preservative ethanol) with next generation sequencing technology, we hope to establish a complete picture that reflects the biodiversity found within an ecosystem.