Environmental DNA Metabarcoding Reveals Divergent Patterns of Biodiversity, Community Assembly, and Environmental...

Area of Science:

• Ecology
• Environmental Science
• Molecular Ecology

Background:

• Understanding how different biological groups respond to environmental changes is crucial for effective river ecosystem management.
• Distinct environmental selection processes shaping spatial patterns of riverine communities are understudied.

Purpose of the Study:

• To investigate the shared and distinct environmental selection processes influencing eukaryotic plankton and fish communities in two adjacent rivers with contrasting conditions.
• To compare the community assembly patterns (stochastic vs. deterministic) and environmental drivers for plankton and fish.

Main Methods:

• Utilized environmental DNA (eDNA) metabarcoding to characterize eukaryotic plankton and fish communities.
• Analyzed alpha and beta diversity, distance-decay relationships, and community variation in relation to physical, chemical, and nutrient variables.

Main Results:

• No significant difference in alpha diversity between rivers for either group, but strong differences in beta diversity indicating high spatial turnover.
• Both plankton and fish communities exhibited distance-decay relationships, stronger in plankton.
• Plankton community assembly was primarily stochastic, while fish assembly was predominantly deterministic.
• Community variation was significantly associated with physical-chemical factors (EC, pH, WT, DO, COD, BOD5) for both groups.
• Plankton communities additionally responded to nutrient variables (TP, TN, NH4-N).

Conclusions:

• Environmental selection processes differ significantly between plankton and fish communities in riverine ecosystems.
• Water quality parameters are key drivers shaping these communities.
• Findings provide a scientific basis for developing targeted river restoration and water quality improvement strategies.