How do you track biodiversity loss? Check air filters, say scientists
CBC
It's no surprise that along with the wildfire ash, pollen, dust and other particles that can be found floating in the air we breathe, there are also fragments of genetic material from plants and animals.
A new study by Canadian and British scientists reveals a novel way of harnessing that material to help track changes in the environment.
Those genetic fragments that animals and plants shed through skin, scales, fur or excretion are known as environmental DNA (eDNA). They can give researchers clues to the biodiversity of an area by showing what creatures are present there more easily than other methods.
The eDNA can be gathered by installing small air filters, similar to those used to cool computers and 3-D printers, directly in the habitats scientists want to monitor.
But while these are capable of collecting data on a small scale, researchers at Toronto's York University and two institutions in the U.K. found that there are gadgets monitoring air pollution all around us that have already inadvertently been collecting eDNA on a large scale for decades.
Called air-monitoring stations, they're used by most countries to measure air quality. Canada has nearly 260 of them installed across the country, everywhere from St. John's to Mississauga, Ont., to Burnaby, B.C.
The researchers behind the study, published in Current Biology Monday, collected samples from two stations in fall 2021 — one in a park in London and the other in a field north of Edinburgh. They found eDNA from 182 different species of plants, fungi, insects, mammals, birds, fish and amphibians.
"It was far more than we expected," said co-author Elizabeth Clare, assistant professor of biology at York University in Toronto. "That was one of the biggest shocks to us."
The samples revealed the presence of everything from cabbage to soy beans to the little owl and the red deer.
Clare said she and her colleagues were surprised to find that such a trove of information was under their noses the whole time.
"The idea that there is a system that's out there, collecting it daily over and over and over again, that's basically semi-automated, and that we've never noticed that it exists, that's the thing that is so astonishing, is that this data is already there," she said.
While many air-monitoring stations would not have held onto their air filters over time, the researchers said, some may have records dating back to the 1970s.
Collecting eDNA can help researchers identify the types of organisms living in an ecosystem, known as biodiversity, without having to observe them directly and can paint a picture of what's going on with certain species over time.
International treaties such as the Convention on Biological Diversity commit Canada and other countries to monitoring biodiversity to assess and compare rates of species decline.