Genetic traces captured from air samples reveal a long term biodiversity decline over 34 years in northern Sweden.
A research team reconstructed ecosystems near Kiruna by reading DNA fragments preserved on archived air filters.
Technicians had swapped out the air filters weekly, creating a record as DNA fragments clung to the dust caught in the fibers.
The work was led by Per Stenberg, an associate professor at Umeå University in Sweden.
Stenberg’s research explores how land use and climate pressures leave lasting genetic patterns across northern ecosystems.
Finding life in airborne DNA
A monitoring station outside Kiruna supplied the material, and staff archived the filters in storage rooms for decades.
Air currents carry pollen, spores, and skin cells, which settle on filters as solid fibers catch them.
This approach brings environmental DNA sampling from water to land, using DNA fragments that linger in the air after cells break down.
The floating particles, or aerosols, are tiny bits of airborne solids and liquids that can carry traces of DNA.
Because winds carry aerosols over long distances, the DNA reflects nearby species as well as distant biological sources.
Reading airborne DNA
The researchers built the dataset by washing filters for fragments, and then using DNA sequencing to read genetic code.
Short DNA pieces often dominate older samples, and computers match those snippets to reference libraries from known organisms.
Careful lab controls matter because stray human DNA or lab dust can slip into samples unnoticed.
Grouping DNA signals
The analysis relied on machine learning, software that learns patterns from data, to assign fragments to organism groups.
About 2,700 organism groups appeared near the station, and the analysis tracked changes across branches of life.
Plants, fungi, insects, birds, fish, and large mammals all left detectable signals, including moose and reindeer.
Tracking air movement
Air-flow modeling supported the work by estimating where sampled air traveled, helping narrow DNA sources.
Weather data and particle physics mapped paths, so the analysis could separate local forest signals from distant regions.
Tracing air paths matters for interpretation, because a rare signal might reflect transport rather than local presence.
Comparisons with field surveys
Traditional field surveys checked the results, and both approaches often rose and fell together.
Field teams can miss shy species or brief blooms, while this method can miss organisms that shed little DNA.
Combining both methods can reduce blind spots, and this approach adds coverage when storms or darkness block surveys.
Biodiversity decline detected
Long-term patterns revealed a biodiversity decline from the 1970s to the early 2000s in the region.
The researchers found that birch declined, along with wood-associated lichens and fungi. The pattern points to changes in forest structure.
Parallel shifts in microbes and insects suggest the method captured changes that cut across food webs.
Forest and land use changes
Climate records could not explain the decline, and forest management emerged as a likely pressure.
Land use change is a major driver of biodiversity loss, and northern forests are impacted through logging and road building drivers.
Selective cutting and even-aged planting can simplify habitat by reducing tree age diversity and dead wood, which many specialist species rely on.
Limitations of airborne DNA detection
The approach cannot count exact population sizes, because different species shed DNA at very different rates.
Temperature, sunlight, and microbes drive degradation, chemical and biological breakdown of DNA, and those processes complicate long-term comparisons of DNA.
Reference databases remain incomplete for many insects and fungi, so the analysis sometimes labels DNA broadly.
Global air filter networks
Air-monitoring networks operate at many sites worldwide, and archived filters could reveal similar histories elsewhere.
Routine air-quality sampling can collect DNA from many taxa, and some programs store filters for years, creating hidden biodiversity logs.
Costs still matter, but this method can reuse infrastructure instead of building new traps and survey routes.
An early warning system
Communities need early warning when ecosystems lose diversity, and this approach can detect changes before forests are visibly altered.
Genetic variation and invasive species can appear early in DNA traces, supporting disease and pest tracking.
Land managers often lack baseline surveys, and this method can rebuild timelines to guide restoration and harvest plans.
Future studies can expand the archive, using additional filters to test how quickly management decisions ripple through food webs.
Open datasets could then allow comparisons across regions, while safeguarding sensitive species locations.
“This work is the result of nine years of intense research and development. I look forward to applying these data, together with ongoing sequencing of additional filters, to a wide range of questions,” said Daniel Svensson, a co-author of the study.
The research is published in the journal Nature Communications.
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