Advancing airborne eDNA sampling methods for monitoring diverse terrestrial vertebrate communities.

Effective biodiversity survey methods are crucial to monitor ecosystems threatened by climatic fluctuations and anthropogenic pressures. Here we advance methods for collecting a novel source of biodiversity data - airborne environmental DNA (eDNA), and investigate whether it yields habitat- and season-specific signatures of terrestrial vertebrate communities. Using custom-made, portable, and low-budget samplers, we sampled airborne eDNA in three protected nature areas across Denmark spanning different nature types and seasons. We show that coarse grade air filters, larger filter area, increased airflow rate, and dry storage of filters at -20 °C yield detections of higher numbers of vertebrate taxa with more consistent detections of communities across samples. Further, we find that detected vertebrate communities are characteristic of the sampled nature types and seasons. Collectively, these refinements enable effective monitoring of terrestrial vertebrate biodiversity using portable and low-budget air samplers.