Traditionally, species monitoring has often relied on physical observations of organisms in the field. Often, this requires expertise in species identification. Also, surveys can be labor-intensive, particularly when surveying in remote areas or for organisms that are rare or difficult to find. But today, there is a powerful new approach that gets around some of these problems: environmental DNA (eDNA).
Organisms continually shed cells containing their DNA into their surroundings. The DNA persists in the environment, where it can be collected as an air, soil, or water sample, extracted, and analyzed for any species of interest.