Haplotype-level metabarcoding revealed the relationship between species occurrence and population genetic structure at the catchment scale in aquatic insects

A longstanding question in ecology and evolutionary biology is understanding the evolutionary mechanisms whereby some species appear frequently while others do not. Current research examined this phenomenon through computer simulations and empirical studies involving a few species, while community-wide investigations of this relationship in natural settings remain largely unexplored. To address this, we employed haplotype-level bulk DNA metabarcoding to infer haplotypes from many aquatic insect species with varying occurrence in a catchment. We identified 891 haplotypes belonging to 200 taxonomically identified Operational Taxonomic Units (OTUs). Results showed that species with higher occurrence in the catchment had greater {gamma}-genetic diversity, a wider range of environmental conditions, and an increased probability of {beta}-species-genetic diversity correlations (SGDC). We found negative -SGDC in species with lower occurrence in the catchment. Dispersal abilities and environmental factors may influence the relationship among species occurrence, population genetic structure, and SGDC. Our findings present a novel approach to address the association of species occurrence and population genetic structure, as well as SGDC, from a community-level perspective. This has important implications for addressing biodiversity loss driven by rapid environmental changes from human activities and climate change.