Seasonal Differences in Fish Community Structure in the Upper Yangtze River Based on eDNA Metabarcoding: A...

Area of Science:

• Ecology
• Environmental Science
• Molecular Biology

Background:

• Understanding seasonal dynamics of aquatic ecosystems is crucial for conservation.
• Environmental DNA (eDNA) metabarcoding offers a non-invasive approach for fish community monitoring.
• The upper Yangtze River harbors diverse fish fauna, but its seasonal variations are understudied.

Purpose of the Study:

• To monitor fish communities in the upper Yangtze River across four seasons using eDNA metabarcoding.
• To analyze seasonal variations in fish community structure, species composition, and functional groups.
• To investigate the relationships between fish communities and environmental variables.

Main Methods:

• Collected eDNA samples from 14 sites along the upper Yangtze River over four seasons.
• Utilized eDNA metabarcoding for fish species identification and community structure analysis.
• Applied 16 multidimensional diversity indices to assess taxonomic and functional diversity.

Main Results:

• Detected 120 fish species, predominantly sedentary, omnivorous species with sticky eggs.
• Observed higher sequence reads for drifting egg, migratory, and carnivore fish in autumn/winter.
• Found significantly higher functional, α, taxonomic, and phylogenetic diversity in spring/summer compared to autumn/winter.

Conclusions:

• Fish diversity is higher in spring and summer, likely due to increased fish activity during spawning and enhanced eDNA shedding in warmer conditions.
• Ecological niche overlap is more pronounced during the spring and summer seasons.
• eDNA metabarcoding provides valuable insights for seasonal fish monitoring and understanding community dynamics in large river systems.