New Knowledge on Aquatic Invasives

11/9/2016

A packed house for the opening plenaries. Photo courtesy Timothy Campbell
Post by Jenny Seifert, UWEX Outreach Specialist

Sharing knowledge and building boundary-spanning relationships are essential to stopping the spread of aquatic invasive species. This is why over 600 aquatic invasive species professionals from across the Upper Midwest descended upon La Crosse in October to take part in the biennial Upper Midwest Invasive Species Conference.

Among the presenters, attendees and organizers were staff members from the Wisconsin Department of Natural Resources and the agency's many state partners. Wisconsin benefits greatly from participation by program staff, because it means they can bring home and apply new knowledge and solutions to protect the state's native environment, upon which its economy, recreational traditions and ecological resilience depend.

In this post, we share a sampling of information from the conference that may be helpful to those who enjoy Wisconsin's great outdoors.

Did you know that regulations about the harvest, sale and use of live fishing bait vary across states? This can create difficulties for anglers who cross state lines to fish. One workshop brought together Mississippi Basin states to discuss how to harmonize regulations, which can lead to more effective cross-boundary prevention.

Across our western boundary, managers in southeast Minnesota are using an innovative method to control invasive carp that could be an effective management tool in Wisconsin, too. Minnesota's Riley lake chain had an abundant carp population that had thrown the lakes' fisheries off balance and lowered water clarity. To suppress the population, managers run an aerator in the local marsh during the winter, where carp go to spawn. This creates conditions that allow native bluegill sunfish to survive the winter there and forage on the carp eggs and larvae. As a result, carp populations have declined dramatically since the aeration unit was installed in 2011. Read this report to learn more.

The boundaries that all species – native and nonnative alike – heed are climatic. A region's weather will make it attractive or prohibitive to certain species. Given that, several states, including Wisconsin, discussed how they can use computer models that predict the changing long-term weather trends to reevaluate which invasive species they need to keep their eyes out for in early detection monitoring.
Surveying the historical bounds of invasive species management, one DNR staff member presented on the need for a holistic approach moving forward. What this means is, when a new invasive is detected in a waterbody, we mustn't panic. The differing ways we can control invasive species have impacts of their own – some of them no better than those of the invasive species. So careful consideration of the options and the factors at stake will be crucial to making the right management decision.

Careful consideration could entail assessing the effects of invaders. Researchers from the UW-Madison Center for Limnology presented a variety of approaches to measuring and comparing the impacts of invasive versus native species on a lake's community of aquatic plants. Such comparisons are important because people often attribute differences they observe between waterbodies to the presence (or absence) of an invasive species. However, each ecosystem is unique, diverse and dynamic. So the effect people are seeing may not actually have anything to do with the invasive species in question. By improving our understanding of invasive species' actual impacts, a comparative approach could help improve the practicality of invasive species management and ensure that management decisions provide the most good for our lakes and rivers.

A case in point is research by DNR scientists on controlling Eurasian water milfoil, an invasive aquatic plant in Wisconsin. In essence, they found milfoil doesn't have a uniformly negative impact on native plants and the presence of milfoil isn't related to a decline in native plants in most lakes. In fact, the researchers didn't find anything unusual about how milfoil interacts with other plant species the way it behaves within the whole plant community is similar to some native species. Moreover, large-scale or whole-lake herbicide treatments, one way of trying to control milfoil, often have a greater effect on the plant community than what would be expected if the milfoil was left alone, indicating a need to weigh the costs and benefits of such a treatment. This research will lead to smarter milfoil management and healthier ecosystems.

Finally, one DNR staff member was inspired by a speaker's call to enhance the impact of scientific research by integrating more business savviness. Currently, few people are trained in both science and business, and combining those disciplines could lead to fruitful solutions and innovative enterprises for healthy communities and ecosystems.

They learned and shared much more than this, of course. You can bet that the management solutions they are working on will reflect the innovative ideas and valuable connections they collected.