Envision having a "genetic dossier" that, by examining environmental genetic remnants, outlines all the flora and fauna in a certain vicinity, similar to how a meteorological forecast enumerates precipitation, temperature, and wind. This was considered a wild concept by scientists not too long ago. However, a recent study has made it apparent that consistent, remote biodiversity surveillance could be in the near future. By utilizing existing air pollution monitoring instruments, scientists have identified a cost-effective method for conducting a census of local species.
Chris Jerde, a non-participating ecologist from the University of California, Santa Barbara, lauds the cleverness of the study. Julie Lockwood, another external ecologist from Rutgers University, asserts that this presents a prime opportunity for large-scale biodiversity surveillance, an obligation countries have pledged to carry out as part of the Convention on Biological Diversity.
The study is a fresh development on the mounting proof that environmental DNA, or eDNA, is an effective shortcut to recording species, mitigating the need for more labour-intensive conventional sampling techniques like trapping or direct observation of individual plants or animals. The ubiquity of eDNA is beginning to emerge, states Kristine Bohmann, a molecular ecologist at the University of Copenhagen. Large animals shed DNA through skin, scales, and feathers, and eDNA has also been found in a variety of creatures and plants, both on land and in water. In the past two years, several research groups, including Bohmann's, have managed to detect DNA from plants, insects, and mammals suspended in the air.
Physicist James Allerton, working at the National Physical Laboratory (NPL) in England, suspected that the inadvertent collection of eDNA could already be happening through airborne pollution monitoring. Allerton, who is involved in a decades-long air quality tracking project by the U.K. government, partnered with biologist Elizabeth Clare from York University. Clare's team had already proven that eDNA samples from zoo air encapsulated the biodiversity within the facility. Biologist Joanne Littlefair from Queen Mary University of London also joined the endeavor, and together, they decided to investigate if the country's air quality monitor filters had gathered eDNA in tandem with air pollutants.
eDNA was indeed found on the filters of an air monitor at NPL in suburban London and on filters from a Scottish monitoring station that had been in storage for 8 months. The DNA revealed the existence of 180 different forms of plants, fungi, insects, mammals, and amphibians, including 34 bird species at both sites, the team reports in Current Biology. Notably, the filters also contained DNA of endangered species like hedgehogs and songbirds, several tree types, and crops like wheat and cabbage. "It is truly remarkable that filters gathered originally for other objectives can be repurposed for sensitive eDNA research," says Naiara Rodríguez-Ezpeleta, an eco-evolutionary geneticist at AZTI in Sukarrieta, Spain.
Even though the Scottish filters had been stored for 8 months, there was minimal variation between the quantity and types of species identified at both sites. Previously, researchers believed that DNA would deteriorate over that time period. This revelation "opens up fascinating prospects for eDNA research," Rodriguez-Ezpeleta remarks. Presuming the old filters are kept dry to preserve the DNA, it could be feasible to retroactively trace biodiversity changes by examining archived filters, suggests Clare.
This is precisely the approach geneticist Per Stenberg from Umeå University has taken in yet-to-be-published work. His team has managed to extract DNA from three decades worth of stored air filters. These filters, replaced weekly, were part of a network aimed at detecting radioactive fallout from nuclear blasts across Sweden. The filters have collected enormous volumes of air
