The study of aquatic invasive species and their many ecological impacts have comprised an important and ongoing part of NTL-LTER research since the site’s inception in 1981.  In fact, much of the current understanding of how lake ecosystems and food webs change in response to species invasions is a direct result of NTL-LTER research: several of these lakes were invaded by exotic species in the 1980s and ‘90s, providing a unique opportunity to measure long-term change in response to biological invasions (Wilson et al. 2004).  Yet as aquatic invasive species such as Eurasian watermilfoil, rainbow smelt, zebra mussel, and spiny water flea proceeded to spread to the many thousands of lakes in the region, it became apparent that a broader geographic focus was needed in order to understand the spread and impact of these species.

Our focal species for modeling spatial distribution of invasive species was rainbow smelt (Osmerus mordax).  They were shown to have dramatic ecological impacts in LTER core study lakes, as they compete with and prey upon the young of native fishes (Hrabik et al. 1998, Beisner et al. 2003, Mercado-Silva et al. 2007).  The species continues to spread, and now occupies >25 lakes in Wisconsin, and many hundreds of lakes in the Laurentian Great Lakes region.  Our approach was to develop statistical models predicting smelt presence/absence in Maine lakes, where smelt are native (Mercado-Silva et al. 2006).  Application of this model to lakes in Wisconsin identified ~ 550 lakes to be environmentally suitable for rainbow smelt.  This indicates that rainbow smelt distributions are far from saturated (<5%) on the Wisconsin landscape.  Further analysis of these lakes revealed that only a subset of the environmentally suitable lakes should reasonably be considered ‘vulnerable’ to invasion.  Some lakes do not have road access or residential development, and are thus unlikely to be subject to an introduction.  Other lakes do not contain populations of the fish species – walleye, yellow perch, lake herring – that based on NTL-LTER research, are known to be negatively impacted by rainbow smelt.  Taking into account these additional factors produces a list of less than 200 lakes in Wisconsin that are considered ‘vulnerable’ to rainbow smelt.  From a resource managers perspective, this is a tractable number of lakes, and in theory, allows education and prevention efforts to be focused on these vulnerable lakes.

Several other regional-scale studies of aquatic invasive species have been conducted as part of this work.  A multi-species study found that impounded lakes were significantly more likely to support populations of invasive species compared to natural lakes (left Johnson et al. 2008). Solomon et al. (2010) detected Chinese mystery snail (Bellamya chinensis) in half the lakes surveyed in the NHLD, but found little effect upon native snail communities.

Based on the above research program, we have been developing and testing the viability of what we call a ‘smart prevention’ approach for invasive species management (Vander Zanden and Olden 2008).  The core idea is that access to environmental suitability and lake vulnerability information can help resource managers make better decisions, and more effectively prioritize their planning and management efforts.  Though it would seem that this information could be very useful to resource management staff, in reality, there were likely to be several constraints.  Understanding how this approach could be implemented requires working directly with resource managers and ensuring that they have access to meaningful and interpretable information about site vulnerability to specific invasive species.

We have been involved in a number of activities to help promote the implementation of this management approach.  In the last year, we held four role-playing workshops focusing on the idea of allocating resources to combat the spread of an invasive species.  Our research focused specifically on assessing how lake vulnerability information was used in the workshops, and how management outcomes differed in the presence or absence of such information.  In cooperation with the Wisconsin DNR, we have produced a ‘how-to’ video to help others interested in holding this type of ‘smart prevention’ workshop.  In addition, we launched a new website (screenshot on right) with three components: 1) an online mapping tool for lake suitability to aquatic invasive species, 2) smart prevention workshop materials, and 3) an overview of AIS research conducted at the UW Center for Limnology.  Our web-based mapping tool currently includes assessments for two aquatic invasive species: zebra mussel and rainbow smelt.  It is designed to provide managers and the general public with access to our assessments of lake vulnerability for > 11,000 Wisconsin lakes (Papes et al. in review).  We will continue to add new species as they become available.  Since March of 2010, the site has had >3000 thousand visits, and is increasingly used by state and county staff in their efforts.

References

• Beisner, B. E., A. R. Ives, and S. R. Carpenter. 2003. The effects of an exotic fish invasion on the prey community of two lakes. Journal of Animal Ecology 72:331-342.
• Hrabik, T. R., J. J. Magnuson, and A. S. McLain. 1998. Predicting the effects of rainbow smelt on native fishes in small lakes: Evidence from long-term research on two lakes. Canadian Journal of Fisheries and Aquatic Sciences 55:1364-1371.
• Johnson, P. T., J. D. Olden, and M. J. Vander Zanden. 2008. Dam invaders: impoundments facilitate biological invasions in freshwaters. Frontiers in Ecology and the Environment 6:357-363.
• Mercado-Silva, N., S. Gilbert, G. G. Sass, B. M. Roth, and M. J. Vander Zanden. 2007. Impact of rainbow smelt (Osmerus mordax) invasion on walleye (Sander vitreus) recruitment in Wisconsin lakes. Canadian Journal of Fisheries and Aquatic Sciences 64:1543-1550.
• Mercado-Silva, N., J. D. Olden, J. T. Maxted, T. R. Hrabik, and M. J. Vander Zanden. 2006. Forecasting the spread of invasive rainbow smelt in the Laurentian Great Lakes region of North America. Conservation Biology 20:1740-1749.
• Papes, M., M. Sallstrom, T. R. Asplund, and M. J. Vander Zanden. in review. Transferring non-indigenous species research to resource management and planning. Conservation Biology.
• Solomon, C. T., J. D. Olden, P. T. J. Johnson, R. T. Dillon, and M. J. Vander Zanden. 2010. Distribution and community-level effects of the Chinese mystery snail (Bellamya chinensis) in northern Wisconsin lakes. Biological Invasions 12:1591-1605.
• Vander Zanden, M. J., and J. D. Olden. 2008. A management framework for preventing the secondary spread of aquatic invasive species. Can. J. Fish. Aquat. Sci. 65:1512-1522.
• Wilson, K. A., J. J. Magnuson, D. M. Lodge, A. M. Hill, T. K. Kratz, W. L. Perry, and T. V. Willis. 2004. A long-term rusty crayfish (Orconectes rusticus) invasion: dispersal patterns and community change in a north temperate lake. Canadian Journal of Fisheries and Aquatic Sciences 61:2255-2266.