Integrating eDNA and morphology reveals arsenic-associated assembly processes of benthic invertebrates in coral reef...

Understanding how climate change and human activities affect the biodiversity and community assembly of benthic invertebrates is essential for monitoring and conserving coral reef ecosystems under accelerating environmental stress. Environmental DNA (eDNA) metabarcoding provides a rapid, standardized tool for biodiversity assessment, yet limitations such as primer bias and incomplete reference databases prevent it from fully replacing traditional morphological identification. Here, we proposed an integrated framework that combines morphological identification with eDNA metabarcoding to enhance the accuracy and scalability of benthic invertebrate diversity assessments in coral reef ecosystems. Our results demonstrate that metabarcoding detects only about half of invertebrate genera, while morphological methods show even greater taxonomic gaps. This underscores the complementary strengths of the two methods for comprehensive biodiversity monitoring. Based on the framework, we identified arsenic (As) as a pivotal role associated with invertebrate community assembly. We observed a transition from stochastic to deterministic processes as As heterogeneity increased. Overall, our study demonstrates that combining eDNA and morphology provides a robust and scalable approach to detect ecological shifts, characterize biodiversity, and understand how environmental stressors-particularly heavy metal pollutants-shape invertebrate community dynamics in coral reef ecosystems. These findings have important implications for biodiversity monitoring, pollution assessment, and the conservation of fragile coral reef ecosystems under global environmental change.