Airborne eDNA Reflects Human Activity and Seasonal Changes on a Landscape Scale

Abstract

Recent research on environmental DNA (eDNA), genetic material shed by organisms into their environment that can be used for sensitive and species-specific detection, has focused on the ability to collect airborne eDNA released by plants and carried by the wind for use in terrestrial plant populations, including detection of invasive and endangered species. Another possible application of airborne eDNA is to detect changes in plant communities in response to activity or changes on a landscape-scale. Therefore, the goal of this study was to demonstrate how honey mesquite, blue grama, and general plant airborne eDNA changes in response to human activity on a landscape-scale. We monitored airborne eDNA before, during, and after a rangeland restoration effort that included honey mesquite removal. As expected, restoration activity resulted in a massive increase in airborne honey mesquite eDNA. However, we also observed changes in abundance of airborne eDNA from the grass genus Bouteloua, which was not directly associated with the restoration project, and we attribute these changes to both human activity and seasonal trends. Overall, we demonstrate for the first time that activity and changes on a landscape-scale can be tracked using airborne eDNA collection, and we suggest that airborne eDNA has the potential to help monitor and assess ecological restoration projects, track changes due to global warming, or investigate community changes in response to encroachment by invasive species or extirpation of threatened and endangered species.

Airborne environmental DNA metabarcoding for the monitoring of terrestrial insects - a proof of concept

“…The samplers differ in whether they sample particles actively (by sucking in air) or passively (sedimentation plates). Passive air samplers have been used successfully in two recent pilot studies targeting airborne eDNA from honey mesquite (a non-anemophilous plant) (Johnson, Cox, and Barnes 2019; Johnson et al 2021). They are less costly and do not rely on a power source, and can therefore be deployed for extended amounts of time.…”

“…While an interesting proof of concept, it was performed on rather artificial conditions, inside an animal housing room with high densities of the target species. The only studies to explicitly sample airborne eDNA other than pollen or spores in an outdoor environment for the detection of macroorganisms are Johnson, Cox, and Barnes (2019) and Johnson et al (2021) who successfully detected the insect pollinated shrub honey mesquite outside of its flowering season. To the best of our knowledge no targeted detection of airborne insect DNA has been attempted to date.…”

Airborne Environmental DNA Metabarcoding Detects More Diversity, More Efficiently, Than a Traditional Plant Community Survey

“…This can be explained by examining the ecology of blue grama, which is pollinated in the fall (Event 9) and then goes dormant in the early summer (Event 21). During this dormancy, it is not growing, owering, or pollinating, which minimizes its production of airborne eDNA (23).…”

“…To collect airborne eDNA, we deployed Big Spring Number Eight (BSNE) dust traps at the center of each site (N = 9) for the traditional survey (Fig. 1a; [21][22][23]. Each BSNE trap consisted of two independent triangular metal collectors approximately 0.9 and 0.4 m above the ground (Fig.…”

“…Additionally, Johnson et al (21) found that not only could species be detected that were not wind pollinated, but also during a season when target species are not owering and pollination is not occurring. Furthermore, Johnson et al (23) found that airborne eDNA trends correspond to seasonal patterns and acute disturbances on a short-grass rangeland landscape. More recently, Aalismail et al (24) found that airborne eukaryotic communities (including plant species) could be detected with samples from the global dust belt over the Red Sea.…”