Reconstructing hyperdiverse food webs: gut content metabarcoding as a tool to disentangle trophic interactions on coral reefs

1. Anthropogenic stressors have strong impacts on ecosystems. To understand their influence, detailed knowledge about trophic relationships among species is critical. However, this requires both exceptional resolution in dietary assessments and sampling breadth within communities, especially for highly-diverse, tropical ecosystems. 2. We used gut content metabarcoding across a broad range of coral reef fishes (8 families, 22 species) in Mo’orea, French Polynesia to test whether this technique has the potential to capture the structure of a hyperdiverse marine food web. Moreover, we explored whether taxonomic groups (families) and traditional, broad-scale trophic assignments explained fish diet across four different metrics of quantifying predator-prey interactions. 3. Metabarcoding yielded a large number (4,341) of unique operational taxonomic units (i.e. prey) with high-resolution taxonomic assignments (i.e. often to the level of genus or species). We demonstrate that across multiple m...