Study on the biodiversity of macroinvertebrate in the Dayang River Basin during summer based on environmental DNA and morphological analysis

The health of the Dayang River ecosystem, critical freshwater resource for Dandong City, is intertwined with local water management and coastal development. In June 2023, we conducted a biodiversity survey in the Dayang River basin using a combined morphological and environmental DNA (eDNA) approach. We assessed both species and functional diversity of summer macroinvertebrates. A total of 81 macroinvertebrates species were identified, with some overlap in species detection between the methods. The trunk stream exhibited lower species diversity with uneven distribution across sites, whereas the tributaries displayed a more stable species composition. Functional diversity analysis mirrored this pattern, revealing lower functional diversity in the trunk stream, indicative of intense competition and niche occupation. Conversely, the tributaries displayed more uniform and complete functional diversity. This study highlights the differential influence of hydrological environments on macroinvertebrate communities during the summer season, with the trunk stream favoring certain species with specific habitat preferences and adaptations. Furthermore, it underscores the value of combining traditional morphological surveys and eDNA techniques for comprehensive biodiversity assessments.