Presentations:

Tools to identify water bodies critical to the western spread of an invasive species by David Creamer, Michigan State University Department of Fisheries and Wildlife

Damaging aquatic invasive species, such as the zebra mussel (Dreissena polymorpha), pose an ongoing concern for potential introduction and establishment in the western United States. This study applied habitat suitability indices and network analysis to identify lakes critical to the continued westward spread and establishment of zebra mussels from a key invasion front in Texas. Creamer at al. created multiple networks consisting of lake nodes and connecting roadway edges. Via graph analysis, lakes critical to mussel spread by acting as hubs, stepping stones, or cut points in each network were identified. Additionally, this presentation will cover the development of a production constrained gravity model. This model is used to simulate the movement of boats within the study area as a proxy for introduction risk and is combined with habitat suitability indices to estimate the overall invasion risk to lakes in Texas and eastern New Mexico.

Don’t move a mussel: The role of key environmental drivers and management scale in assessing spatial variation in dreissenid spread risk in the Missouri River basin by Michael Springborn and Joseph Raymond, University of California Davis

Management efforts such as watercraft inspection and detection programs that attempt to intercept infected watercraft can help limit dreissenid mussel spread, but optimizing the effectiveness of these programs under limited resources is complicated. There is limited work that has considered the heterogeneous impact of protection efforts across different regions and waterbodies. Knowledge about this heterogeneity can highlight regions that would benefit the most from protection as well as regions that would require less effort to protect, e.g., areas with naturally unsuitable water quality for dreissenids. To this end, the research team constructed a composite relative risk index (CRR) for watersheds within the Missouri River Basin, a region in the United States on the front line of dreissenid spread. The CRR uses a model that mirrors an expected value model but uses relative indexing as a proxy for the model components. The CRR incorporates a wide array of data sets to account for the direct and indirect damages from a potential infestation along with the risk of an infestation occurring. The CRR index includes user-specified weights for certain parameters so that a user can adjust the relative importance of various factors to match their specific context. An accompanying web tool allows users to view the CRR results and adjust multiple parameters to see the resulting impacts on the CCR for watersheds in the Missouri River Basin.