Robust passive sampling of airborne environmental DNA to monitor plants and animals

Airborne environmental DNA (eDNA) is a rich resource for understanding biodiversity, but its wider application is hindered by its complex collection methods and unknown sampling time effects. To develop a passive sampling scheme that is effective and convenient, we systematically compared the performance of an array of materials, namely common filter membranes, electrostatic dust cloth [EDC] and coated microscope slides, for collecting airborne eDNA under a natural setting in two seasons. Metabarcoding analysis of the captured eDNA revealed a rich diversity of plants (485 taxa) and vertebrates (132 taxa), but different samplers varied significantly in detecting that taxonomic richness, with EDC strongly outperforming the other materials. Our investigation of sampling time effects showed a rapid, daily compositional turnover of plant assemblages uncovered by airborne eDNA. Using EDC, prolonged sampling was negatively correlated with the detected plant richness but positively so with animal richness. Overall, we provide empirical evidence for a very simple and economical passive sampler of airborne eDNA that can effectively detect considerable biodiversity in natural environments. Our findings also support the use of airborne eDNA for monitoring plant and fungal phenology and community shifts at a high temporal resolution.