Collecting information on the presence of species without sampling these species directly is a new approach in biodiversity research. Such an approach is possible due to improvements of DNA methods, increasing their throughput and sensitivity. With such improvement it is often sufficient to collect samples from the environment to detect its DNA, the so-called environmental or e-DNA to detect a species. However, despite the sensitivity of this approach it may still only detect DNA of sufficient quantity. Further, given its high sensitivity, contamination of samples becomes an important issue.
A recent study in California’s Sequoia Kings Canyon National Park may be a first case, but needs further confirmation that e-DNA can be an early warning signal of pathogen-caused mass mortalities. The authors may only have found e-DNA of the deadly amphibian pathogen Batrachochytrium dendrobatitis because an outbreak was imminent and therefore the quantity of DNA in the lake water was sufficiently high. Generally, it is an interesting approach, but care needs to be taken in overstating what such an approach can do. Maybe P³ can give some more indications at the end of this year, when we have first results from sequencing of our e-DNA samples. E-DNA may be also an interesting approach to determine how climate change impacts on mountain biota.
A hibernation accident or a disease victim?
Much care needs to be taken when taking e-DNA samples
Rana temporaria in a small brook. No, this is not photoshopped.