Key environmental factors influencing eDNA quantitative detection of golden mussel (Limnoperna fortunei) in a long-distance water diversion project

The golden mussel (Limnoperna fortunei) invasion and biofouling has caused huge economic and ecological damage worldwide, notably associated with inter-basin water diversion projects that bridge different biogeographical areas and facilitate dispersal of this species. Use of environmental DNA (eDNA) technology for monitoring golden mussel population has become increasingly prevalent but still restrained because of unclear quantitative relationship between eDNA concentration and densities of golden mussel. This study commenced with field surveys collecting the datasets of eDNA concentration, mussel density, and environmental parameters in the world's largest water diversion project. An exponential quantitative relationship between the eDNA concentration and density of golden mussel was successfully established. Meanwhile, water temperature and pH were identified as the critical environmental factors influencing this exponential relationship through recursive feature elimination. To further investigate these influences, generalized additive models were developed to capture variations in the quantitative relationship. The confirmation of a quantitative relationship by this study underscores the efficacy of eDNA as a tool for density quantification, paving the way for high efficiency and resolution detection of invasive species like golden mussel, and offering a proactive approach to ecological preservation and resource management.