5 Conclusions
Our study used eDNA macrobarcoding technology to investigate the distribution and composition of fish communities in subtropical river systems. eDNA-based fish investigation was as effective as electrofishing-based investigation in both composition and diversity analysis. The relative OTU richness (%) at the taxon-specific level could effectively distinguish the dominance of fish communities. The composition of fish communities in each spatial zone could be indicated by local biomarkers, which could identify the specificity of the local environment in each spatial zone. The response between environmental factors and genus- and species-level OTU richness was effective enough to indicate the ecological relationships between the environment and fish communities. Macrobarcoding-based eDNA technology has great potential to be used in field monitoring of fishes, and even extend to invertebrates and the food web.