Although the results mostly have implications for wildlife conservation, this research was carried out in a zoo and I found very interesting, so will post it here.
Environmental DNA (eDNA) is being increasingly used to monitor species presence in wild situations, but it is not known how well some methods work. To test the effectiveness of airborne eDNA collection on species identification, the researchers placed three air filters at different sites of Copenhagen Zoo and examined what eDNA was recorded in them.
The first filter was sited in a stable for okapi and red forest duikers. As well as successfully detecting both of these species, the apparatus also recorded thirteen birds and mammals kept in neighbouring enclosures elsewhere in the southern section of the zoo, one zoo species from the northern section of the zoo, two wild pests (brown rat and house mouse), of which one is also kept at the zoo and used as feed (the mouse), two wild or domestic non-zoo species known to occur in or around the zoo (water vole and domestic dog) and two fish used as animal feed (salmon and smelt).
The second filter was located in an open-air location close to several outdoor mammal and bird enclosures in the southern section of the zoo. Of the thirty-five bird and mammal species with access to an outdoor enclosure in the southern section, twenty-one were recorded. Also identified was one animal from the northern section of the zoo, three wild pests (of which two are also used as feed), four wild or domestic non-zoo species known to occur in or around the zoo and one fish species used as feed.
The third filter was located in the rainforest section of the zoo's Tropical House. Twenty-nine species were detected in total, including nine of the twenty-four vertebrates inside the house itself (one of these, the Dumeril's ground boa, is kept in a terrarium). In addition, five species from within the Tropical House but away from the rainforest section were detected, four species used as feed, seven species from outside the Tropical House, the domestic cat and dog and two rodent pests.
The eDNA was so effective that it even managed to allow identification of individual animals - two different ostriches, five white rhinos, twenty-five helmeted guineafowl and forty-seven Javan sparrows were identified.
The findings show that monitoring biodiversity using airborne eDNA is possible. The full article is included here:
DEFINE_ME
Title: Airborne environmental DNA for terrestrial vertebrate community monitoring
A similar study was also done recently at Hamerton Zoo, which also found that while eDNA is most concentrated to species close to the filters, it can carry a distance from the enclosure, supporting the findings of the Copenhagen study. This paper can be found here:
DEFINE_ME
Title: Measuring biodiversity from DNA in the air
A news article about both bits of research is included here:
https://phys.org/news/2022-01-zoo-air-dna-animals.html
. A note of caution is that the results are largely based on correlations, validated mostly by a priori hypotheses. So it might be difficult to validate the direction of some of the relationships. They also only used population within 10 km as an indication, not a larger area, and they ignored tourism in the area, so there might be a way to improve the study.
