eDNA metabarcoding bioassessment of endangered fairy shrimp (Branchinectaspp.)

Habitat degradation and land-use change severely threaten the survival of fairy shrimp and the vernal pools in which they live. Limiting effective fairy shrimp conservation management efforts is the ability to readily identify species without the capture and sacrifice of individuals for microscopy. Here we demonstrate that eDNA metabarcoding is an effective non-invasive tool for monitoring fairy shrimp. Results from ten Southern California vernal pools comparing eDNA and traditional dip-net methods showed that eDNA metabarcoding with16SrDNA provides exceptional species-level resolution. Importantly, while the two methods were concordant during early hydroperiods where adults were present, eDNA detected fairy shrimp for up to 2 months after dip-nets failed to detect any adults, expanding the time period for vernal pool monitoring. Together, these results provide resource managers a simple, cost-effective, and non-invasive method for biomonitoring endangered fairy shrimp species.