Spatial Complexity and Rare-Taxon Turnover Structures Benthic Coral Reef eDNA Communities

Area of Science:

• Marine Ecology
• Molecular Ecology
• Biodiversity Assessment

Background:

• Environmental DNA (eDNA) metabarcoding revolutionizes biodiversity assessments.
• Its ability to differentiate persistent from dynamic ecological communities over time is understudied.
• Understanding eDNA temporal consistency is crucial for interpreting biodiversity data.

Purpose of the Study:

• To assess the temporal stability of eDNA signals on coral reefs.
• To determine if eDNA reflects consistent community composition or short-lived fluctuations.
• To investigate how temporal variation influences biodiversity data interpretation.

Main Methods:

• Assessed Hawaiian coral reef communities over two years.
• Utilized two universal eDNA markers: nuclear 18S and mitochondrial COI.
• Analyzed community composition, site distinctiveness, and temporal variation patterns.

Main Results:

• Community composition varied significantly across sites but remained relatively stable within sites over time.
• A core assemblage of persistent taxa (sponges, annelids, red algae) was consistently detected.
• Temporal variation was driven by rare/transient taxa and influenced by environmental factors like wind and tides.

Conclusions:

• eDNA signals primarily reflect underlying spatial heterogeneity, not transient fluctuations.
• Routine eDNA surveys can robustly track coral reef community dynamics across space and time.
• eDNA-derived patterns align with visual surveys, enhancing ecological interpretation.