eDNA On the Go: A Direct Comparison of Fixed and Vehicle Mounted Airborne eDNA Sampling Methods for Terrestrial Vertebrate Species Detection

ABSTRACT

Air is receiving increasing recognition as a biologically rich source of taxonomically diverse environmental DNA (eDNA). Multiple proof‐of‐concept studies have explored air as a medium for the detection of single terrestrial species and even entire terrestrial communities, including mammals, non‐anemophilous plants, and arthropods. Airborne eDNA has been sampled using various stationary devices, but if we can access it using mobile collection methods, we can rapidly assess biodiversity at large spatial scales. We therefore compared passive eDNA filters deployed for short (40 min) and long periods (6 days) with filters attached to cars that sampled transects through natural and human‐modified environments. eDNA Metabarcoding with the 12S‐V5 general vertebrate primer pair detected 46 vertebrate taxa (32 birds, 13 mammals, and 1 reptile). Long‐term passive sampling identified both the highest number of taxa (34) and unique detections (14), followed by mobile sampling (24 taxa, 5 unique detections) and short‐term passive sampling (21 taxa, 3 unique detections). Community composition differed significantly among sampling methods but not between land uses. We found that sampling effort, particularly duration and replication, is a dominant driver of detection success. This study demonstrates that optimizing sampling design is more important than selecting a specific sampling method and that different sampling approaches should be viewed as complementary tools suited to different field contexts. We propose that car‐mounted air DNA sampling could be an effective method for large spatial scale, rapid biomonitoring efforts.