Community science volunteers have contributed a fantastic amount of observational data points that are now paramount to tracking biodiversity turnover over space and time (Bird et al., 2014). The Global Biodiversity Information Facility (GBIF; Robertson et al., 2014) integrates collection and observation data curated by thousands of institutions (n=1332 publishers as of January 11, 2019). One major source of observations is the iNaturalist (Cal Academy of Sciences; CAS) platform, which had exceeded 5.5 million ‘research grade’ or photographed records in GBIF (as of January 11, 2019). With this increase in photographic observation, how can other kinds of scientific data help fill in the gaps of where people cannot go and what a camera cannot see?
Environmental DNA (eDNA) presents an attractive method for obtaining alternative biodiversity data. It is considered largely non-invasive--extracted from soil, sediment, or water--and can be passively collected with unmanned devices or easily collected by volunteers given minimal training, gloves, tubes, and a means of recording time and place (e.g. CALeDNA; www.ucedna.com; Meyer et al., 2019). eDNA can be subjected to targeted sequencing that can cover all kingdoms of life.
However, one suspected caveat of eDNA methods is that they most reliably inventory small bodied, more evenly distributed species over large mobile organisms. In turn, to address this gap, eDNA-based biodiversity inventories may benefit by being complemented with human observation data that by nature focus on relatively larger organisms. Logistically, it is possible to arm the large population of community scientists with both tools for simultaneous monitoring of eDNA and visually observable species, and move society closer to solving some of the challenges to monitoring taxonomic, genetic, and functional biodiversity.
This study is a test of the extent of overlap between human observation and eDNA metabarcoding signals from community science collections. We focus on a beach containing the Pillar Point reef that has been heavily surveyed by the California Academy of Sciences (CAS) Citizen Science volunteer group and staff (https://www.inaturalist.org/projects/intertidal-biodiversity-survey-at-pillar-point). Samples for environmental DNA were collected by community scientists and staff of the University of California CALeDNA program (www.ucedna.com). We matched eDNA targeting prokaryotes and eukaryotes to published DNA sequences that included barcodes of California coastal species that had been recently generated by the Los Angeles Natural History Museum’s Diversity Initiative of Southern California’s Ocean (DISCO). The community inventories from eDNA and GBIF were compared and the biodiversity turnover across different zones of the beach was evaluated to demonstrate the extent these two data types can complement each other and inform future DNA barcoding efforts. One of these zones is a State Marine Conservation Area (SMCA) that we evaluate for its effectiveness as a biodiversity refuge. Results were reframed here as interactive web pages for community scientists, natural areas managers, and potential eDNA adopters to explore.