Developing and testing a new molecular assay for early detection of zebra mussel veligers
This project developed an early detection molecular assay for detecting and quantifying zebra and quagga mussel DNA in environmental mixtures of the two species. At present, the assay is applicable to plankton tows containing veliger larvae, but it could be easily modified for midwater or lake-bottom samples as a more conventional “eDNA” assay. It is a highly sensitive test. The greatest contribution of this test is the simultaneous detection of both species, present together in the same water samples, since there is at present no convenient, reliable method for separately quantifying larvae from quagga and zebra mussels in mixtures. Recently we showed that there is no apparent bias in estimating the relative abundance of DNA from both species, and we showed that the assay reliably quantifies veligers, even in tow samples that are filled with DNA from other species of planktonic animals. Because several water bodies have both species; quagga reproduction in Minnesota is unknown; adults in the upper Mississippi River in Minnesota are scattered but in fairly high numbers (in important potential source locations like Lake Pepin); and more broadly since quaggas have replaced zebra mussels in the lower Great Lakes, further application of the assay to estimate reproductive output of the invader — still on the horizon for Minnesota — would be useful.
Pilot work in Minnesota has shown that starry stonewort populations and growth patterns of can vary between years and between lakes in different locations. These patterns suggest that how starry stonewort invades a lake could be influenced by climatological factors such as ice-out date, growing season length, and average water temperature. If this is the case, then developing effective management strategies for starry stonewort requires a deeper and more specific understanding of how climate change will influence the invasion dynamics of the species.
The project includes:
- An empirical study of starry stonewort invasion dynamics in nine lakes across latitudinal gradients in Wisconsin, Minnesota, and Indiana.
- Interviews with AIS managers and decision-makers in Wiscnsin, Minnesota and Indiana to examine invasive species management perceptions and preferences as they relate to starry stonewort.
- Modeling starry stonewort invasion patterns under a range of climate and management scenarios.
This project will provide practical information on the ecology of starry stonewort, a summary of current stakeholder preferences around starry stonewort management, as well as an evaluation of optimal management strategies.
The study is one component of a larger research project that is funded by the Prepared for Environmental Change Grand Challenge initiative administered by the Environmental Resilience Institute at Indiana University.