What is Environmental DNA (eDNA)?

​​​Environmental DNA, or eDNA is a non-invasive biodiversity monitoring tool scientists and managers use that captures the genetic material organisms shed into their environment as a natural byproduct of being alive (their metabolic waste). Once captured, isolated, and amplified (think a xerox machine for DNA), these genetic signals allow us to detect species presence and relative abundance, revealing how ecosystems function through time and space. Knowing who shed how much DNA at a given moment can help us detect endangered or invasive species, assess biodiversity, estimate occupancy, track migrations and spawning events, monitor range shifts, and infer food-web structure and habitat suitability.

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Importantly, eDNA signals are shed at predictable, often species-specific rates and are shaped in systematic ways by environmental conditions (e.g. microbial community activity, temperature, flow, pH, and water chemistry) that make each ecosystem unique. As a result, effective implementation of eDNA techniques requires integrating methods, data, and ways of knowing from disciplines that are often treated in isolation. These include ecology, organismal biology, genomics, geology, hydrology, chemistry, limnology, oceanography, sedimentology, and fluid dynamics, among others. By interpreting the genetic signals observed over time and in the field through these connected but disparate perspectives, eDNA becomes a powerful tool for understanding how ecosystems respond to human activity, climate change, resource development, and restoration actions, across scales ranging from individual species to entire watersheds.