April 2018 newsletter
Letter from the Director
Hello from MAISRC!
A lot has been accomplished in MAISRC’s short life, and I hope you have all had a chance to see the highlights in our recent five-year report. As we have taken stock in our progress, equally as impressive has been the statewide reach of the research efforts. From Lake of the Woods up north to Pool 8 of the Mississippi River – and hundreds of locations in between – MAISRC researchers and citizen scientists have been working all across the state to understand and solve our AIS problems. Check out this interactive map to see what has been done in your area!
Unfortunately, the threats posed by AIS are also statewide. Common carp in southern Minnesota and spiny waterflea in the northeast. Zebra mussels in lake country and Eurasian watermilfoil in the metro. Of course, those lines can blur together, but you get the idea: strategic and impactful research to address all of Minnesota’s AIS problems can be a challenge. This is why MAISRC is important – bringing researchers, managers, and many other diverse stakeholders together to work towards solutions in a coordinated and prioritized way.
Funding to make all this happen has primarily been provided by the Environment and Natural Resources Trust Fund, as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR). We recently submitted another proposal to the LCCMR to extend this base funding for the Center to 2023 and continue to offer competitive research grants on high-priority research needs. If you, your lake association, agency, or other group is interested in providing a letter of support for this proposal, please let us know at firstname.lastname@example.org – it would really help!
To everyone that has made our research progress (and those ‘dots on the map’) possible – thank you!
Time to get back to the lab…
New research challenges assumptions about biodiversity-invasibility relationships in lakes
New research from MAISRC is challenging assumptions about the biotic resistance of native lake ecosystems to aquatic invasive species.
Scientists analyzed an unprecedently large dataset of aquatic vegetation surveys from 1,102 lakes that had been gathered over 13 years to conduct this research. The team evaluated evidence for four distinct mechanisms that are commonly understood to drive patterns of native and invasive species richness: biotic resistance, competitive exclusion, environmental filtering, and environmental heterogeneity.
The results were surprising: researchers found no evidence for local-scale biotic resistance to invasions, a major paradigm for invasions. “Everybody has an instinct that diverse plant communities are inherently more resilient to invasions, but they’ve got limits,” said Dr. Ranjan Muthukrishnan, lead researcher on the project.
The team did find evidence of competitive exclusion, meaning that native species richness decreases when invasive plants arrive. They also found that native species richness decreased at many locations where invasive species richness was higher, such as at deeper depths or higher-nutrient lakes. This suggests that invasive plants are more tolerant to a wider range of conditions, better exploit degraded systems such as lakes with excess nutrients, and are overall better able to adapt to less-than-ideal conditions than native plants. That broader tolerance may be an important aspect of how invasive species are able to spread. The invasive plants included in the study were purple loosestrife, Eurasian watermilfoil, reed canarygrass, curly-leaf pondweed, narrow-leaf cattail, and hybrid cattail.
“This research is helping us understand the fundamentals of how invasions work,” added Muthukrishnan. “Much of this work had previously been done on terrestrial ecosystems, and it was easy to assume it would be similar in aquatic plant communities. It’s not.”
Finding no overall evidence that sites with more diverse plant communities are less likely to be invaded underscores the importance of preventing the spread of aquatic invasive species to begin with. It also suggests that managing watersheds to support and improve water quality may be a more effective means of mitigating invasions and their impacts.
“If you want to be able to make fine grain decisions about how to allocate resources, you must first know what the problem is,” added Muthukrishnan.
Read the full paper here, and learn more about invasive plants research at MAISRC.
Fishing equipment and spreading spiny water flea: What’s the highest risk?
Researchers are making significant progress toward developing best practices for cleaning recreational equipment to prevent the spread of spiny water flea. An initial analysis of data from last summer’s field work shows that during the daytime, fishing lines gather a lot of spiny water flea. During twilight hours, when spiny water fleas are moving up the water column to feed, live wells also appear to be ensnaring a lot of animals.
To study this, researchers simulated the use of fishing equipment on Island Lake Reservoir. Each simulation was designed to replicate slow trolling. During each simulation, they used three stationary anchors, three towed fishing lines (monofilament, braided, and fluorocarbon), a towed downrigger with steel cable and monofilament line, a towed bait bucket, and a simulated live well. They also used plankton nets to determine the ambient density of spiny water fleas in the lake.
“By comparing pieces of gear to each other and to the ambient density, we can determine which items, at which times of day, are most risky for spreading spiny water fleas,” said Dr. Donn Branstrator, lead researcher on the project.
“It’s commonly believed that human recreational activity is the primary vector of spread for spiny water flea, but little is known about the specific pathways they take,” added Dr. Valerie Brady, co-researcher. “Through this research, we hope to be able to draw attention to specific pieces of equipment that should be the focus of cleaning efforts so we can minimize the risk of spreading spiny water flea to any new lakes.”
Going forward, similar field work will be conducted this summer on Lake Mille Lacs. Final results from this project are expected in summer 2019.
Spiny water flea are a small freshwater zooplankton that invades lakes and can take over the bottom of the food chain. They can decimate populations of Daphnia and other native zooplankton, resulting in a decreased food source for native fish and an increase in algal blooms. They can also clog the eyelets of fishing rods, causing problems for recreationalists. They have been confirmed in 35-40 lakes in Minnesota. Drying equipment for at least six hours is the most effective way of preventing spread.
Learn more about this research on our website.
New carp-killing virus discovered in Minnesota for the first time
Researchers from the Minnesota Aquatic Invasive Species Research Center recently confirmed the presence of Carp Edema Virus (CEV) in Minnesota waters, the first time it has been recorded in wild fish in the state. Researchers are paying close attention to this virus, and considering its potential as a biocontrol agent for invasive common carp.
The virus was first discovered in common carp from a fish kill event in Lake Jonathan in Carver County. It was later found in dead common carp from Cottonwood Lake in Lyon County. Both instances were confirmed by the University of Minnesota Veterinary Diagnostic Lab, who also found Koi Herpes Virus (KHV) to be present. Both fish kill events had high mortality.
In 2017, Lake Elysian in Waseca County made news for being the first lake in which KHV was discovered in wild populations of carp in Minnesota. Since then, MAISRC researchers have confirmed KHV in six more Minnesota lakes. Now, they’re exploring whether these pathogens – individually or combined – could be harnessed to control invasive common carp.
“These viruses are promising control options because they only affect carp, and they are easily transmissible and highly lethal,” said Isaiah Tolo, a PhD student on the project. “The presence of these viruses in Minnesota waters give us a chance to study their impact on invasive carp and determine if they are a tool we could use to control this species.”
MAISRC researchers will continue to gather samples from fish kill events this summer to diagnose cause of mortality. Next, the team will work to isolate both viruses, sequence their genomes, and conduct infection trials to ensure they won’t impact native fish. Conducting risk assessments, developing release strategies, and consulting with the public and regulatory agencies will follow.
If you see a fish kill event, please report it to help this research. Go to z.umn.edu/fishkill for an easy-to-use reporting app. Your report will be sent to MAISRC researchers who will collect samples and diagnose the cause of mortality.
Common carp are one of the world’s most ubiquitous invasive species. They dominate the fish biomass of many shallow lakes, rivers, and wetlands in Minnesota, especially in central and southern parts of the state. When they root in the lake bottom for food, common carp destroy native plants, harm waterfowl habitat, and degrade water quality.
To learn more about this research, please visit our website.
Register today to become an AIS Detector!
Registration is now open for AIS Detectors, a volunteer network and science-based training program launched by the Minnesota Aquatic Invasive Species Research Center in partnership with University of Minnesota Extension.
If you are a concerned, motivated individual over the age of 18 who wants to learn more about AIS and do your part to protect Minnesota’s precious lakes, this program is for you! After being certified as an AIS Detector, you’ll serve a critical role by helping search for new AIS infestations, providing outreach to your community, and helping AIS researchers in the field. In-person workshops are coming up in:
- Victoria on April 27
- Owatonna on May 4
- Willmar on May 11
- Brainerd on May 18
- Duluth on June 1
By joining this network of engaged Minnesotans, you’ll receive high-quality, scientist-reviewed training, build your skills in AIS identification and reporting, and become part of the solution to AIS problems in Minnesota. Details, answers to frequently asked questions, and registration information is available on MAISRC's website.
Recently published papers
- Biology, ecology, and management of starry stonewort (Nitellopsis obtusa): A Red-listed Eurasian green alga invasive in North America (Dan Larkin et al)
- Predicting the Impacts of Heterosporis sutherlandae on the Yield of a Yellow Perch Population: An Integrated Modeling Approach (Megan Tomamichel)
- Dispersal mechanisms for zebra mussels: population genetics supports clustered invasions over spread from hub lakes in Minnesota (Michael McCartney and Sophie Mallez)
- Effect of non-native versus native invaders on macrophyte richness: are carp and bullheads ecological proxies? (Przemek Bajer and Peter Hundt)
- Assessing the efficacy of corn-based bait containing antimycin-a to control common carp populations using laboratory and pond experiments (Przemek Bajer, Josh Poole, Blake Sauey, Jon Amberg)
- A decade of common carp research and management in Minnesota (Przemek Bajer)
- Source-sink dynamics explain the distribution and persistence of an invasive population of common carp across a model Midwestern watershed (Justine Dauphinais, Loren Miller, Reid Swanson, Peter Sorensen)
- Response of the invasive alga starry stonewort to control efforts in a Minnesota lake (Wesley Glisson, Carli Wagner, Steve McComas, Kevin Farnum, Michael Verhoeven, Ranjan Muthukrishnan, Dan Larkin)
- Environmental filtering and competitive exclusion drive biodiversity‐invasibility relationships in shallow lake plant communities (Ranjan Muthukrishnan, Nicole Hansel-Welch, Dan Larkin)
- Zebra mussels and Eurasian watermilfoil reporting patterns in Minnesota (Kaushi Kanankege, Moh Alkhamis, Andres Perez, Nicholas Phelps)
Save the date for the Showcase
Mark your calendars! The fifth annual Minnesota Aquatic Invasive Species Research and Management Showcase will be held on Wednesday, September 12 on the University of Minnesota St. Paul campus. Learn about all the exciting work going on at MAISRC at this day-long conference filled with informative talks, hands-on demos, lab tours, and more. This is your best opportunity to learn about the latest findings in AIS research, useful management tools, and get an inside-peek into our state-of-the-art lab. Registration will open mid-summer – stay tuned! 3
We want to hear from you!
Has research from the Minnesota Aquatic Invasive Species Research Center had an impact on your work, or that of your lakeshore association? Let us know! Send an email to email@example.com with how MAISRC research informed your decision-making, or made you feel more empowered to make a difference in the fight against AIS. Or maybe there’s a specific MAISRC research effort that you’re particularly excited about – we’d love to hear from you!
Our researchers are working diligently to address the AIS issues that are threatening Minnesota’s waters. Help us do this critical work with a gift today -- private contributions to MAISRC make a real difference and provide us with the flexibility to meet critical needs as they arise. Thank you!