eDNA metabarcoding reveals differences in fish diversity and community structure in Danjiang River

Area of Science:

• Aquatic ecology
• Molecular ecology
• Conservation biology

Background:

• Fish diversity is crucial for aquatic ecosystem health but faces threats like pollution and climate change.
• Effective monitoring is essential for fish diversity conservation.
• Traditional fish surveys can be limited in scope and sensitivity.

Purpose of the Study:

• To investigate fish diversity in the Danjiang River using environmental DNA (eDNA) metabarcoding.
• To compare the effectiveness of eDNA metabarcoding with traditional fish capture methods.
• To identify key environmental factors influencing fish community distribution.

Main Methods:

• High-sensitivity environmental DNA (eDNA) metabarcoding.
• Analysis of fish species composition, including rare and exotic species.
• Correlation analysis between fish distribution and environmental factors (temperature, pH, ORP).

Main Results:

• Identified 59 fish species across eight orders and 19 families.
• Cypriniformes and Perciformes were dominant orders; Cyprinidae was the most abundant family.
• eDNA metabarcoding detected significantly higher fish richness compared to traditional ground cage surveys.
• Temperature, pH, and oxidation-reduction potential were identified as key environmental drivers of fish distribution.
• Eight rare and two exotic fish species were detected.

Conclusions:

• eDNA metabarcoding is a powerful and sensitive tool for assessing fish diversity, outperforming traditional methods.
• The study provides valuable data for fish diversity management in the Qinling Mountains.
• Improving local genetic databases is crucial for the broader application of eDNA metabarcoding.