Why are researchers vacuuming up animal DNA in the forest?

64 animal species

But the vacuumed DNA traces indicated more than 64 animal species were present in the forest, such as cows, pigs, sheep, chickens, dogs, and exotic pets such as parakeets and peacocks. There were also wild animals such as red deer, roe deer, Eurasian badgers, white-tailed eagles, red foxes, different vole species, robins, Eurasian red squirrels, common toads, smooth newts, great crested newts, cranes, great spotted woodpeckers, nuthatches, grey herons, marsh tits, woodcocks – and many more.

“It's absolutely crazy! Although we have worked hard to optimize the method, we did not dare to hope for such good results. We didn't think we would succeed so well in the very first attempt in nature," said associate professor Kristine Bohmann.

“Animals secrete DNA into their surrounding environment all the time. It could be in the form of fragments of hair, feathers and skin cells. If they are airborne, we can vacuum them and use DNA analyses to find out which animals they came from," added Lynggaard.

Take me to the zoo!

Last year, the researchers undertook a similar experiment at the Copenhagen Zoo.

"There is quite a difference between a zoo and nature," said Bohmann. "In a zoo, the animals are present in large numbers in a relatively small area, while in nature they are much less concentrated. Therefore, we were unsure how well we could make the method work in nature. And that is where we have to get it to work if we want to use it to monitor biodiversity.”

Now, the scientists believe they have a valuable biodiversity tool in their hands.

"We are in a biodiversity crisis, and tools are needed to understand how ecosystems change as a result of human impacts, to guide management strategies and to assess the risk of the spread of diseases in areas where animals can come into contact with people," added Lynggaard.

“As with all new methods, we have a lot of work ahead of us. But this study makes us hopeful. It demonstrates a sensitive method for mapping the presence of animals without having to see or disturb them," noted Bohmann.

The study was published in the journal Molecular Ecology Resources.

Study abstract:

The current biodiversity and climate crises highlight the need for efficient tools to monitor terrestrial ecosystems. Here, we provide evidence for the use of airborne eDNA analyses as a novel method for detecting terrestrial vertebrate communities in nature. Metabarcoding of 143 airborne eDNA samples collected during 3 days in a mixed forest in Denmark yielded 64 bird, mammal, fish and amphibian taxa, of which the detected 57 ‘wild’ taxa represent over a quarter of the around 210 terrestrial vertebrates that occur in the overall area. We provide evidence for the spatial movement and temporal patterns of airborne eDNA and for the influence of weather conditions on vertebrate detections. This study demonstrates airborne eDNA for high-resolution biomonitoring of vertebrates in terrestrial systems and elucidates its potential to guide global nature management and conservation efforts in the ongoing biodiversity crisis.