Environmental DNA Standardization Needs for Fish and Wildlife Population Assessments and Monitoring
Natural resource management requires accurate information regarding “at-risk” and invasive species, wildlife population trends, and ecosystem health and response to environmental perturbation.
For fish and wildlife taxa, conventional survey methods generally rely on direct observation of target taxa, which can be stressful and damaging to them and their habitat. Common sources of conventional survey bias may include:
- variation in applied effort and observer skill
- ease of sampling in different habitats
- taxa-specific differences in detectability between seasons
- taxa density and distribution, and
- sampling equipment
A new approach to environmental assessments and monitoring involves sampling environmental DNA (eDNA) that is present in sediments, soil, water, or air through secretions, excretions, or exogenous sloughing of skin cells. eDNA methods have the distinct advantage of using unique sequence segments of genetic material to identify taxa without coming into direct contact with the target taxa or performing onerous morphology-based taxonomic identifications.
The high sensitivity of eDNA methods can dramatically increase detection rates, particularly for species that occur at low densities, have secretive ecologies, feature discontinuous distributions, or share morphological traits that confound accurate identification. Furthermore, eDNA methods are more cost-effective, non-invasive, and more accurate than conventional survey methods.
As eDNA methods are increasingly utilized for environmental assessment and monitoring activities, their results will have greater influence upon management decisions. Indeed, they have the potential to revolutionize environmental assessment and monitoring. Despite the power of eDNA detection methods, addressing specific issues to remove barriers to the adoption of eDNA methods and enhance confidence in their use is vital. These include quality issues with regards to accuracy and reliability, lack of accredited national standards for both sample collection and analysis, and the need for demonstrated competency and proficiency testing by practitioners.
This report represents a consensus-based synthesis of the current understanding of eDNA methods with information drawn from available published literature; from expert-led interviews, discussions, and workshops; and from questionnaire responses obtained from experts, practitioners, end-user groups, and regulatory agencies across Canada, United States, and Europe.