During the holiday season, many homes are decorated with soft green moss. Some people collect it from nearby forests, while others buy it from shops. It looks harmless and decorative, but moss hides a surprising secret.
Tiny fragments of DNA from animals, plants, and microbes settle into it over time. Every creature that moves through an area leaves behind small traces of genetic material, and moss quietly collects them.
A new study led by the University of Copenhagen shows that moss acts as a natural collector of environmental DNA, often called eDNA.
This discovery comes at an important time. Species are disappearing rapidly, and climate change is reshaping ecosystems around the world.
Scientists are looking for simple, reliable ways to monitor biodiversity, and moss may offer one of the easiest solutions yet.
Does moss store
The idea behind the study did not start in a lab. It began during fieldwork on the Danish island of Christiansø.
Biologist Kasun Bodawatta experienced a moment that sparked a new way of thinking about this common plant.
“I was doing fieldwork on the Danish island of Christiansø when I tripped and fell on a patch of soft moss. And then I thought: Hey, it’s just like a sponge,” said Bodawatta.
“Maybe moss works like sponges that absorb environmental DNA, just as sea sponges can be used to collect DNA in marine ecosystems.”
After this realization, Bodawatta and fellow researchers from the University of Copenhagen decided to test whether moss really could store DNA from its surroundings.
DNA in tiny moss samples
The research team collected small moss samples from Lille Vildmose, a protected nature reserve in Denmark.
Each sample measured just 6 by 6 centimeters, yet the results were striking. From these small pieces, the scientists identified DNA from a wide range of living organisms.
The researchers detected 13 species of birds, including graylag goose and common redstart. They also found 11 species of mammals such as bison, badger, and pipistrelle bat, along with two amphibian species.
Beyond animals, the moss contained traces of 54 invertebrates, 21 plants, 553 bacterial genera, and 210 fungal genera.
“By simply swabbing the surface of tiny pieces of moss with a cotton bud, we were able to detect wild, local animals like bison and badgers – and not just pig DNA, which is spread across much of the Danish landscape,” said Bodawatta.
“This shows the great potential moss has for monitoring natural biodiversity.”
A simple method with potential
Environmental DNA is already widely used to monitor rivers and oceans, but collecting it on land can be difficult. Many methods require costly equipment, trained specialists, or electricity.
Moss offers a practical alternative. Its sponge-like structure traps particles from rain, air, and passing animals – holding DNA in place.
To test whether this method could work beyond Denmark, the researchers collected moss samples from forest and savannah habitats in Ivory Coast.
The moss there also revealed valuable genetic information, suggesting that this approach could be used in many parts of the world.
“The special thing about moss is that it is found on almost every continent and, unlike most other methods, the cotton swab approach requires no electricity, expensive equipment or specialised fieldwork,” said study co-author Kathrin Rousk.
“In principle, you can go for a walk in the forest, swab a handful of moss and get a biological fingerprint of the area.”
Moss keeps DNA from nature
One of the most important benefits of this technique is that it is gentle. In most cases, the moss does not need to be removed or damaged. This makes the method suitable for fragile or protected habitats.
Because it is so simple, it could also be used in citizen science projects, allowing people to help monitor biodiversity in their local areas.
The researchers also discovered that moss collects DNA not only from animals that touch it, but also from those that pass through the air above it.
In the Ivory Coast, moss samples even revealed DNA from a rare bird species that was no longer present, suggesting that moss can store genetic traces for long periods.
“The fascinating thing is that something as simple as moss – something we hardly notice – can tell us so much about the nature around us,” said Bodawatta.
“We still need to refine the technique, but moss is extremely promising as a way to monitor animal and plant life around the world.”
In a changing world, moss may help scientists better understand who shares our landscapes, even when those species are no longer easy to see.
The study is published in the journal Molecular Ecology Resources.
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