An integrated spatio-temporal view of riverine biodiversity using environmental DNA metabarcoding

Area of Science:

• Ecology
• Environmental Science
• Genetics

Background:

• Global freshwater biodiversity is threatened by human activities, necessitating improved monitoring.
• Environmental DNA (eDNA) analysis shows promise for ecosystem-scale biodiversity assessment.
• The optimal spatio-temporal resolution for eDNA-based biodiversity monitoring in rivers is not well-defined.

Purpose of the Study:

• To determine the appropriate spatio-temporal resolution for riverine eDNA metabarcoding to accurately assess freshwater biodiversity.
• To investigate how spatial distance, temporal variation, and environmental factors influence eDNA-based biodiversity assessments.

Main Methods:

• Intensive, spatio-temporal eDNA sampling across five European and North American rivers.
• Collected samples at 19 timepoints between 2017-2018, with spatial sampling up to 35 km apart.
• Analyzed eDNA data alongside environmental variables (river flow, pH, conductivity, temperature, rainfall).

Main Results:

• Riverine biodiversity assessment using eDNA is effective at scales of tens of kilometers, primarily driven by species turnover.
• Seasonal events, such as fish migrations, were detectable through temporal eDNA sampling.
• Environmental factors influenced biodiversity in a taxon-specific manner, indicating habitat filtering effects.

Conclusions:

• Riverine eDNA metabarcoding provides biodiversity insights at ecologically relevant spatio-temporal scales.
• This method is valuable for understanding river community ecology amidst environmental change.
• eDNA monitoring can inform conservation strategies for freshwater ecosystems.