Can airborne eDNA detect invasive species before they are visually observed?

Short Answer: Yes — and this is one of the highest-value practical applications of airborne eDNA for government. Early detection of invasive species before visual observation is possible, and multiple studies have now detected invasive species via airborne eDNA that were absent from conventional monitoring records at the same sites. The method is particularly powerful because a single air filter can simultaneously screen for hundreds of potential invasive species without any prior knowledge of which species to look for. This is a fundamentally different capability from targeted species detection tools.

1. Why early detection of invasive species matters

Invasive species cause an estimated $423 billion in annual economic damage globally (IPBES 2023) and are a leading cause of species extinctions worldwide. The single most effective management intervention is early detection and rapid response — acting during the initial establishment phase before the population spreads beyond control.

Traditional early warning relies on visual observation by field ecologists, citizen scientists, or targeted eDNA surveys for specific species. Each of these approaches has a critical limitation: you can only find what you are looking for. A targeted survey for signal crayfish does not detect New Zealand mudsnails. A camera trap network for red squirrel does not detect grey squirrels in new areas. The invasive species problem requires monitoring for all possible invaders simultaneously.

Airborne eDNA metabarcoding and shotgun sequencing offer exactly this: non-targeted, simultaneous surveillance for all species present.

2. Demonstrated detections of invasive species via airborne eDNA

2.1 UK national survey (Tournayre et al. 2025)

The most comprehensive airborne eDNA invasive species data to date comes from Tournayre et al. (2025), who detected multiple confirmed invasive, pest and disease-vector species in their UK national air quality network survey:

Eastern grey squirrel (Sciurus carolinensis) — confirmed invasive, detected at expected sites
Pacifastacus crayfishdetected in Northern Ireland where the species had been introduced but not yet reported at the specific detection site
Prussian carpdetected at sites consistent with known UK range
Silver carpdetected but not officially recorded in the UK
Asian tiger mosquito vectors, ticks, weevilsdetected at multiple sites

The Pacifastacus and Silver carp detections are particularly significant: these represent species detected by airborne eDNA at sites or in a country where they had not been officially recorded. If verified, this demonstrates genuine early-warning capability.

2.2 Aquatic invasive species via air-water transfer (Ip et al. 2025)

A growing body of evidence shows that eDNA from aquatic organisms can be detected in air samples collected near water bodies. Ip et al. (2025a) demonstrated quantitative airborne detection of spawning Coho salmon from passive air samplers above a stream, and a follow-up community-level study (Ip et al. 2025b; preprint) detected overlapping vertebrate assemblages across paired air-and-water samples. The authors explicitly frame this water-to-air eDNA transfer as relevant for invasive species early warning: airborne samplers deployed along rivers, lakes, or coastlines could passively screen for aquatic invasive species without direct water contact — a significant logistical advantage for biosecurity programmes covering large or inaccessible water networks.

2.3 Plant pathogen detection (Atkinson & Roy 2023)

Atkinson & Roy (2023) demonstrated airborne eDNA detection of an invasive plant pathogen (Phytophthora-related species) from air samples collected in a woodland context, opening the prospect of landscape-scale plant pathogen surveillance without destructive sampling.

2.4 Broad-spectrum biosurveillance (Nousias et al. 2025)

Nousias et al. (2025), using shotgun sequencing of air samples from Florida and Dublin, simultaneously detected vertebrates, invertebrates, bacteria and potential pathogens in a single analysis framework. They demonstrated that the method is "already cost effective, it’s feasible, and it lets us answer a whole lot of new questions" including biosurveillance for health-relevant species.

3. Why airborne eDNA may outperform targeted surveillance for invasive species

3.1 Non-targeted detection

Metabarcoding and shotgun sequencing detect all taxa present in a sample, not just pre-specified targets. A single airborne eDNA analysis can simultaneously screen for:

All listed Invasive Alien Species of Union Concern (EU IAS Regulation)
All CITES-listed species
All national invasive species priority lists
Completely novel arrivals not previously considered

No targeted surveillance programme can achieve this breadth at comparable cost.

3.2 Large spatial footprint and mobile surveillance corridors

A single fixed air sampling station may integrate signal from a ~18 km radius (Tournayre et al. 2025). Mobile deployment extends this further: a mobile sampler traversing route samples a continuous corridor of landscape rather than a single point catchment.

This route-integration property makes mobile eDNA sampling a natural fit for biosecurity surveillance corridors — the network of transport routes, border crossings, ports of entry, and known invasion pathways through which invasive species typically spread. Monitoring a corridor that links a port to an inland distribution centre, or a road corridor through a high-risk habitat, is operationally straightforward with vehicle based sampling.. The same coverage with fixed samplers would require multiple units; with conventional field surveys it would require several specialist survey teams.

3.3 Continuous temporal coverage

Continuous air sampling means that any invasive species that passes through the catchment area at any time leaves a detectable signal. A field survey team that visits a site twice a year could easily miss an invasive species that is present only seasonally or that moves through the area between survey visits. High-risk introduction points — freight terminals, airports, ports, and major road haulage hubs — are also environments where conventional ecological surveying and citizen science recording are typically absent, precisely because they are industrial rather than natural habitats. Airborne eDNA monitoring at such locations has not yet been systematically evaluated in the published literature, but the logic of applying continuous air sampling at points where invasive species are most likely to first arrive is compelling and represents a logical extension of current technology.

3.4 Historical detection capability

For documented invasive species, archived air samples may contain retrospective evidence of when the invasion began — before it was visually detected. This could transform understanding of invasion pathways and lag times, with direct management implications.

4. Limitations and verification requirements

False positives are a real risk eDNA detections can result from long-range transported DNA, database misidentification, or contamination. For species not yet officially recorded in a country, the threshold for triggering management action must be higher determined based on the risk profile and the (un)certainty in the detection.

Verification protocols are neededAn airborne eDNA detection of a high-priority invasive species should trigger targeted follow-up investigation through intensive conventional surveys, citizen science, targeted eDNA sampling, or other methods before management action. The role of airborne eDNA is to flag candidate detections for verification, not to serve as the sole basis for regulatory decisions.

Sensitivity small populations is unknownA single individual invasive crayfish in a river system is unlikely to produce detectable airborne eDNA at a distant monitoring station, but not impossible. The method is sensitive for detection of single individuals but more certain during the growth phase of an invasion, when populations are expanding and DNA flux is increasing.

5. The biosecurity application roadmap

A functional national biosecurity early warning system based on air quality networks would need:

1

Priority species list:A defined list of invasive species of concern to screen for in each region
2

Reference database coverage:All priority species must have high-quality reference sequences
3

Detection thresholds:Defined minimum criteria (number of reads, number of replicate samples) to trigger verified alert
4

Verification protocols:Defined response pathway for unconfirmed detections
5

Reporting chain:Clear pathway from detection to responsible agency notification

None of these are technically novel requirements — they parallel the frameworks already developed for aquatic eDNA invasive species monitoring. Adapting them to the airborne context is achievable within existing regulatory and institutional frameworks.

References

Atkinson CT & Roy K (2023). Environmental monitoring for invasive fungal pathogens of ʻŌhiʻa (Metrosideros polymorpha) on the Island of Hawaiʻi. Biological Invasions 25:399–410. https://doi.org/10.1007/s10530-022-02922-3
Berelson MFG et al. (2025). From air to insight: the evolution of airborne DNA sequencing technologies. Microbiology 171:001564. https://doi.org/10.1099/mic.0.001564
Ip YCA et al. (2025a). Passive air sampling detects environmental DNA transfer from water into air. Scientific Reports. https://doi.org/10.1038/s41598-025-26293-6
Ip YCA et al. (2025b). Vertebrate biodiversity via eDNA at the air-water interface. bioRxiv (preprint). https://doi.org/10.1101/2025.06.13.659655
IPBES (2023). Thematic Assessment Report on Invasive Alien Species. Zenodo. https://doi.org/10.5281/zenodo.7430692
Nousias O et al. (2025). Shotgun sequencing of airborne eDNA achieves rapid assessment of whole biomes. Nature Ecology & Evolution. https://doi.org/10.1038/s41559-025-02711-w
Tournayre O et al. (2025). First national survey of terrestrial biodiversity using airborne eDNA. Scientific Reports. https://doi.org/10.1038/s41598-025-03650-z
Tulloch RL et al. (2025). Winds of Change: Charting a Pathway to Ecosystem Monitoring Using Airborne Environmental DNA. Environmental DNA 7:e70134. https://doi.org/10.1002/edn3.70134

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