Starry Stonewort. A new aquatic invader in Wisconsin. Michelle Nault Wisconsin Department of Natural Resources

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1 Starry Stonewort A new aquatic invader in Wisconsin Michelle Nault Wisconsin Department of Natural Resources Michelle.Nault@Wisconsin.gov Photo: Paul Skawinski

2 What is starry stonewort? Starry stonewort (Nitellopsis obtusa) is a member of the Characeae family. Characeae are green algae that can range in size from centimeters to meters, and are found throughout the world. Not a vascular plant like most our aquatic plant species.

3 Native Range Native to Europe and Asia Endangered species in the United Kingdom and Japan

4 Non-Native Range First documented in St. Lawrence River in 1978; likely transported via international ballast water Documented in lower Michigan inland lakes in the mid-2000s. First documented in Wisconsin (Waukesha Co.) in September Currently known from Indiana, Michigan (Lower), Minnesota, New York, Ohio, Pennsylvania, Vermont, Wisconsin, and Ontario, Canada.

5 Starry stonewort distribution

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7 Starry Stonewort (Nitellopsis obtusa) First discovered in Little Muskego Lake, Waukesha Co. Fall 2014 Now known in 6 Wisconsin Lakes & Sturgeon Bay area Sturgeon Bay, Door Co. Pike, Silver, Green, Washington Co. Little Muskego, Waukesha Co. Big Muskego, Waukesha Co. Long, Racine Co.

8 Green Bay/Lake Michigan Distribution First reported to WDNR by a lake management consultant conducting an aquatic plant survey out on the Sturgeon Bay Channel (Door Co.) Verified by WDNR and the New York Botanical Garden WDNR conducted rapid assessment of public access locations surrounding the initial report Monitoring consisted of random rake tosses via shore off piers, docks, boat launches, beaches, etc.

9 Green Bay/Lake Michigan Distribution

10 Ecology Macroalgae species that can grow up to ~7 ft (2 meters) tall Anchored to the sediments with clear filaments called rhizoids, which resemble fishing line Can persist under the ice in St. Lawrence River In Detroit River, first appears in July with peak biomass in September, and declines beginning in November

11 Habitat Occupies a broad range of habitats Occurs in lakes, ponds, and slow-moving water bodies Can colonize shallow to deep waters up to at least 20 feet (6.1 meters); tolerant of low light conditions Particularly thrives in alkaline, stagnant to slow-moving waters with moderate to high levels of nutrients and calcium

12 Reproduction Fragmentation of the stem Specialized structures called bulbils star-shaped creamy white less than 1/3-inch (~1 cm) Only male starry stonewort has been found in North America. No sexual reproduction Photo credit: Robin Sleith

13 Dispersal Primarily moved by boats, trailers, & anchors Waterfowl not believed to be source of dispersal due to lack of sexual reproduction (zygotes).

14 Impacts Impacts of starry stonewort are largely unknown primarily anecdotal and not science based

15 How might starry stonewort affect a lake? May outcompete native aquatic plants Thick meadows may alter habitat and prevent fish from spawning May become a navigational nuisance in shallow waters (< 6 feet) Photo: Paul Skawinski

16 Identification Related to many native macroalgae in Wisconsin Chara (10+ species) Nitella (9+ species) Tolypella (2 species) Lychnothamnus (1 species) Can be difficult to distinguish non-native starry stonewort from these native species

17 Identification Large compared to most of its native relatives Starry stonewort Nitellopsis obtusa Chara contraria Chara globularis Nitella flexilis Photos: Paul Skawinski

18 Identification Retains its shape when held out of water Starry stonewort Nitellopsis obtusa

19 Identification Smooth stem no bumps or ridges Starry stonewort Nitellopsis obtusa Chara contraria

20 Identification Starry stonewort Nitellopsis obtusa Nitella mucronata Branchlet has a short uneven bract coming off the side Branchlet divides into equal-length parts

21 Identification Starry stonewort Nitellopsis obtusa Branchlet has a short bract coming off the side

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23 Bract cell

24 Identification Starry stonewort produces distinct starshaped bulbils Nitellopsis obtusa (starry stonewort)

25 Identification Most native macroalgae do not produce bulbils; Chara aspera produces round bulbils Chara aspera

26 Identification Horned pondweed (Zannichellia palustris) NATIVE VS. Starry stonewort (Nitellopsis obtusa)

27 Identification Sago pondweed (Stuckenia pectinata) NATIVE VS. Starry stonewort (Nitellopsis obtusa)

28 Management Options Management of starry stonewort has been largely unsuccessful in other states Chemical herbicide treatments (i.e. copper sulfate, hydrothol) may provide temporary nuisance relief, but does not kill the entire plant generally non-selective and may impact native species Physical control hand-removal, DASH, dredging, mechanical harvesting Drawdown? No known biocontrol methods Wait and see Eradication in not a realistic goal

29 Next Steps Prevent the further spread of starry stonewort within Lake Michigan and potentially to inland lakes. Search for starry stonewort at nearby heavily used lakes. Assess the population at newly discovered sites to determine appropriate management. Engage local stakeholders in management planning and education/outreach activities (i.e. CBCW). If management occurs, collect quantitative data to assess efficacy and longevity of control Work with other states and partners to learn and adaptively manage starry stonewort.

30 How can we stop the spread of AIS? Wisconsin State Law requires that prior to leaving a boat launch, you must: Inspect boats, trailers and equipment, including anchors and other places that accumulate sediment Remove all attached aquatic plants, animals and mud Drain all water from boats, vehicles and equipment Never move plants or live fish away from a water body

31 What can marinas do to help? Educate customers via personal interactions and appropriately placed signage on the AIS prevention steps they should take to minimize spread Always perform the AIS prevention steps when moving watercrafts for customers When servicing a watercraft, always perform the AIS prevention steps before test launching it Provide a hot water, high pressure wash to customers who are moving boats that have been slipped throughout the season Keep boat launch areas free of floating vegetation and other debris which could get caught on trailers Report any newly discovered invasive or suspicious plants/animals to local WDNR staff

32 Acknowledgements Mary Gansberg Paul Skawinski Tim Plude Becca Klemme Bob Wakeman Maureen Ferry Amy Kretlow Libby Hess Jeremy Bates Susan Eichelkraut Craig Helker Kari Hagenow Tim Campbell Jenny Seifert Dr. Ken Karol Brad Steckart Onterra LLC

33 Discussion Michelle Nault Northern Lake Michigan Basin Aquatic Invasive Species Coordinator 2984 Shawano Ave. Green Bay, WI