Critical considerations for the application of environmental <scp>DNA</scp> methods to detect aquatic species

TLDR

Environmental DNA (eDNA) offers a powerful, non‑invasive tool for detecting aquatic species, enhancing survey sensitivity for rare organisms while demanding rigorous quality assurance, careful interpretation, and diverse methodological approaches. The authors aim to provide comprehensive guidelines to support the growing use of eDNA in aquatic species detection. Guidelines compiled by an international consortium outline key design elements—field and lab contamination control, appropriate analytical methods, assay validation, inhibition testing, and reporting standards—as well as inference factors such as temporal and spatial dynamics, abundance correlation limits, result uncertainty, and allochthonous DNA sources. The paper synthesizes current knowledge on eDNA application for aquatic macroorganism detection, highlighting critical considerations for reliable implementation.

Abstract

Summary Species detection using environmental DNA ( eDNA ) has tremendous potential for contributing to the understanding of the ecology and conservation of aquatic species. Detecting species using eDNA methods, rather than directly sampling the organisms, can reduce impacts on sensitive species and increase the power of field surveys for rare and elusive species. The sensitivity of eDNA methods, however, requires a heightened awareness and attention to quality assurance and quality control protocols. Additionally, the interpretation of eDNA data demands careful consideration of multiple factors. As eDNA methods have grown in application, diverse approaches have been implemented to address these issues. With interest in eDNA continuing to expand, supportive guidelines for undertaking eDNA studies are greatly needed. Environmental DNA researchers from around the world have collaborated to produce this set of guidelines and considerations for implementing eDNA methods to detect aquatic macroorganisms. Critical considerations for study design include preventing contamination in the field and the laboratory, choosing appropriate sample analysis methods, validating assays, testing for sample inhibition and following minimum reporting guidelines. Critical considerations for inference include temporal and spatial processes, limits of correlation of eDNA with abundance, uncertainty of positive and negative results, and potential sources of allochthonous DNA . We present a synthesis of knowledge at this stage for application of this new and powerful detection method.