EDNA (Environmental DNA) sampling is a method of surveying distribution patterns and population sizes for species within an ecological community. EDNA makes use of genetic deposits that organisms leave behind. Ecologists use hair, fecal matter, feathers, and any other forensic-like evidence that they can find in an environment. Using EDNA to sample populations is minimally invasive and does not involve extracting genetic material directly from the targeted organisms. Anthropogenic disturbances continue to plague ecosystems the world over, affecting species abundance, species variety, migratory patterns, and habitats.
Without biodiversity measurements, conservations can’t know how which species are being lost, or how species populations change over time. Measuring biodiversity is not as simple as measuring force or distance; biodiversity can be understood in a multitude of ways. For example, some researchers use species richness -the total number of different species – to quantify diversity. Others may count the number of individual organisms of each species in an area. What’s important is that the community being sampled gives researchers basic information about the occurrence, distribution, and abundance of the species being observed. Using environmental DNA can avoid putting unnecessary stress on the environment and species involved. Conservationists, then, can use environmental DNA to survey species and habitats while doing their part to keep ecosystems intact.
Sampling builds our knowledge of species and how they are distributed which informs conservation projects and environmental policy. Environmental DNA can carry information about the life of the organism involved, like other creatures it may have interacted with or what foods may be part of its diet. This may not always be possible by photographing species. While it may be possible by capturing and tagging animals, these methods present other limitations.
Some species are simply difficult to detect. This could be because the species itself may be incredibly small, or its population sizes are spread thin, making the targeted species too elusive to observe by conventional means. Sampling with EDNA can eliminate limitations associated with capturing species, photographing them, or tracking them. However, EDNA can not be used to determine population quality information such as bodily features and sex ratios. Therefore, DNA retrieved from environments must be used in conjunction with other detection techniques in some cases.