The goal of this project is to provide Department of Defense (DoD) managers, as well as the general wildlife management community, with environmental DNA (eDNA) tools that can be used to monitor species of concern in rivers. The project will focus on native freshwater mussels, which have their highest species diversity in North America, and thus are of special conservation significance. Furthermore, the ecology and reproduction of mussels provides opportunities for developing and testing models of eDNA transport in rivers. Specifically the project will: (1) build, parameterize, and test a model of eDNA transport in two lotic systems that incorporates biological inputs, environmental factors that can affect these inputs, and hydrodynamic aspects of the river system that affect the movement and retention of eDNA; (2) develop and test eDNA assays that can be used to detect and monitor breeding activity of freshwater mussels.

The project will employ a combination of laboratory experiments, field sampling, and numerical modeling approaches to develop tools. Specifically, an eDNA transport model will be developed to inform sampling protocols for detection of freshwater mussels as well as test the ability to back calculate an estimate of mussel biomass, taking into consideration the stream hydrology and biological and environmental factors of that system. Hydrologic and geomorphic assessments of the study reaches will be conducted in order to inform the eDNA transport model. Laboratory studies will be conducted on focal species in order to measure the biological input for the model, including eDNA shedding and degradation rates, and the effects on these rates of environmental factors such as temperature and food availability. Finally, model performance will be assessed by comparing results to field data acquired through intensive field sampling of the study sites over a year-long period. Samples from laboratory and field work will be analyzed using quantitative PCR (qPCR). The project will also develop a second tool, genetic assays (qPCR) for the detection of male spawning behavior, that can be utilized either in the field or in captive rearing facilities to monitor breeding activity.

This work will aid wildlife managers and the general eDNA community by exploring in more detail the fate of eDNA in natural riverine systems, informing what transport parameters are important to consider in designing monitoring programs, and providing a starting point for eDNA transport models with more mobile aquatic species. In addition, the project will develop assays that can identify reproductive events in the field and the laboratory, thereby aiding endangered mussel management both in the wild and in captive breeding facilities. A number of army installations, including one of the study sites, manages for freshwater mussels, thus these tools could be applicable to other DoD lands.