Starry stonewort: A new aquatic

invasive species in Minnesota

Dan Larkin

April 15, 2016

Photo: Dan Larkin

Overview

• Introduction to starry stonewort

• Applied research on starry stonewort

– Risk assessment

– Control

• Takeaways

– Identification

– Citizen science opportunities

Photo: Dan Larkin

Starry stonewort

Nitellopsis obtusa

• New AIS in Minnesota

• Charophyte (green

algae)

Photo: Paul Skawinski

Starry stonewort

• Native to Europe, Asia

– Endangered in Japan

– Special concern in UK

(JNCC 2010,

Kato et al. 2014)

Photo: Scott Brown

Starry stonewort

• Closely related to

stoneworts /

muskgrasses native

to Minnesota

McCourt et al.

1996

Chara aspera C. contraria Nitella flexilis

Starry stonewort

• Relatively new invader

• Quickly gaining ground

• Increasing concern for AIS management

Starry stonewort

• Relatively new invader

• Quickly gaining ground

• Increasing concern for AIS management

Starry stonewort

• Relatively new invader

• Quickly gaining ground

• Increasing concern for AIS management

Starry stonewort

• Relatively new invader

• Quickly gaining ground

• Increasing concern for AIS management

Starry stonewort

• Lake Koronis (Stearns Co.)

Photos: Google Earth

Starry stonewort

• Reported as highly

invasive in some areas

• Reductions in plant

diversity

• Potential impacts to

spawning habitats

(Pullman and Crawford

2010, Sleith et al. 2015) Photo: Paul Skawinski

Starry stonewort

Michigan

• 128 lakes

• e.g., L. Houghton

– 0 – 3,000 acres in 5y (M. Heilman pers. comm.)

– Frequency nearly

tripled 2013–2015 (Progressive AE)

Photo: Google Earth

Starry stonewort

• How at risk is Minnesota?

• What can we do?

– Limited ecological knowledge

– Limited control toolkit

– High uncertainty

Photo: Dan Larkin

Invasion process

Prevention

Species

absent

Eradication

Rare,

localized

Containment

Rapidly

increasing

Long-term

management

Widespread and

abundant

Invasion stage

(time→)

Ab

un

da

nc

e

Invasion process

Prevention

Species

absent

Eradication

Rare,

localized

Containment

Rapidly

increasing

Long-term

management

Widespread and

abundant

Invasion stage

(time→)

Ab

un

da

nc

e

curlyleaf

pondweed

hydrilla

Invasion process

Prevention

Species

absent

Eradication

Rare,

localized

Containment

Rapidly

increasing

Long-term

management

Widespread and

abundant

Invasion stage

(time→)

Ab

un

da

nc

e

starry

stonewort

×

Invasion process

Prevention

Species

absent

Eradication

Rare,

localized

Containment

Rapidly

increasing

Long-term

management

Widespread and

abundant

Invasion stage

(time→)

Ab

un

da

nc

e

starry

stonewort

Little impact so far

But high uncertainty

about the future

×

Overview

• Introduction to starry stonewort

• Applied research on starry stonewort

– Risk assessment

– Control

• Takeaways

– Identification

– Citizen science opportunities

Photo: Dan Larkin

Risk assessment

• Ecological niche modeling

– Collaboration with Nick Phelps (MAISRC /

Vet Med) and postdoc Luis Escobar

Risk assessment

• Ecological niche modeling – Occurrences from native and invaded ranges

– Model distribution in relation to climate and environmental data

– Predict potential for range expansion

http://www.unil.ch/

Risk assessment

• Ecological niche modeling

Escobar et al. In review

Risk assessment

• Ecological niche modeling

– Exploiting “novel” climate niche in invaded range

Escobar et al. In review

Risk assessment

• Predictions of suitable habitat

Escobar et al. In review

Risk assessment

• As-yet uninvaded areas (Mid-Atlantic, Great Plains, Intermountain West) potential high suitability

Escobar et al. In review

Risk assessment

• Minnesota may have limited suitability

Escobar et al. In review

Next steps

• Investigate these

predictions through:

– Finer-scale risk

assessment for MN lakes

– Climate tolerance

experiments

– Desiccation tests

Figure: DH Montgomery, Pioneer Press

Scaling down to MN lakes

• Chemistry of SSW lakes:

– Fairly clear/low-nutrient

• Oligo-meso to mesotrophic

(S. Brown, MLSA)

– Alkaline (Sleith et al. 2015)

– High calcium carbonate

(Fuller & Taricska 2011)

• Positive feedbacks? (Kufel

& Kufel 2002)

Charophyte meadow in Poland Photo: Piotr Panek

Scaling down to MN lakes

• Chemistry of SSW lakes:

– Fairly clear/low-nutrient

• Oligo-meso to mesotrophic

(S. Brown, MLSA)

– Alkaline (Sleith et al. 2015)

– High calcium carbonate

(Fuller & Taricska 2011)

• Positive feedbacks? (Kufel

& Kufel 2002)

What lakes is it found in now?

What are physiochemical conditions of these lakes?

Which Minnesota lakes overlap with these conditions?

Scaling down to MN lakes

• Chemistry of SSW lakes:

– Fairly clear/low-nutrient

• Oligo-meso to mesotrophic

(S. Brown, MLSA)

– Alkaline (Sleith et al. 2015)

– High calcium carbonate

(Fuller & Taricska 2011)

• Positive feedbacks? (Kufel

& Kufel 2002)

What lakes is it found in now?

What are environmental conditions of these lakes?

Which Minnesota lakes overlap with these conditions?

Scaling down to MN lakes

• Chemistry of SSW lakes:

– Fairly clear/low-nutrient

• Oligo-meso to mesotrophic

(S. Brown, MLSA)

– Alkaline (Sleith et al. 2015)

– High calcium carbonate

(Fuller & Taricska 2011)

• Positive feedbacks? (Kufel

& Kufel 2002)

What lakes is it found in now?

What are environmental conditions of these lakes?

Which Minnesota lakes overlap with these conditions?

Climate tolerance

• Testing climate predictions

– Correlative models

– Nature full of surprises

– Is MN climate limiting for

starry stonewort?

Escobar et al. In review

Climate tolerance

• Growth experiments

– Culture starry stonewort

in new MAISRC lab

– Mimic winter conditions

predicted to be range-

limiting

• Duration

• Photoperiod

• Light quality

Climate tolerance

• Current and

future climate

– Typical

– Severe

– Mild

– Variable

(Hellmann et al. 2008, US

EPA 2008, NOAA 2016) Photo: MAISRC Facebook

Spread risk

• Dioecious, only males

identified in U.S. to date

• Spread by fragments

and “bulbils”

• Concentrated near

accesses / high-use

areas

Sleith et al. (2015)

Spread risk

• Unintentional human

movement fragments

and bulbils

• If contaminated boat…

how long does material

stay viable?

Photo: NYS DEC

Spread risk

Desiccation trials

• Undergrad Carli Wagner

• Environmentally controlled chambers

• Still able to grow after 12h, 24h, 2d, 5d….?

• Different materials

– Fragments

– Bulbils

– Different sized clumps

Photo: Milwaukee Journal Sentinel

Spread risk

Desiccation trials

• Different materials

– Fragments

– Bulbils

– Different sized clumps

Photo: Milwaukee Journal Sentinel

Overview

• Introduction to starry stonewort

• Applied research on starry stonewort

– Risk assessment

– Control

• Takeaways

– Identification

– Citizen science opportunities

Photo: Dan Larkin

Control

• Difficult to control

starry stonewort

– “Haircut” w/ dead

upper but live lower

parts, able to resprout

Pullman and Crawford 2010

Control

• Difficult to control

starry stonewort

– “Seedbank” of bulbils

left behind

– Herbicide sensitivity of

bulbils unknown

Photo: www.mymuskegonow.com/

Control

• Testing sensitivity of

plants and bulbils to

different herbicides

Photo: www.mymuskegonow.com/

Control

• Testing sensitivity of

plants and bulbils to

different herbicides

– Small-scale, high-

replication assays

Photo: MAISRC Facebook

Control

• Testing sensitivity of

plants and bulbils to

different herbicides

– Small-scale, high-

replication assays

• Chelated copper

formulations

• Non-copper herbicides

(diquat, alkylamine

endothall)

Photo: MAISRC Facebook

Control

• Testing sensitivity of

plants and bulbils to

different herbicides

– Larger-scale, more

realistic tests of

promising treatments

Photo: NOAA NCCOS

Control

• Testing non-target

effects on native

charophytes and

vascular plants

Photos: Ville Karvinen, articulo.mercadolibre.com.ec/,

Gary Fleming, C. B. Hellquist)

Extension

• Starry stonewort

working group (June)

– Bringing together

experts from around the

country

Photo: Dan Larkin

Extension

• Starry stonewort

working group (June)

– Synthesizing what is

known: ecology,

impacts, management

– Setting research

agenda Photo: Dan Larkin

Extension

• Starry stonewort

working group (June)

– Synthesizing what is

known: ecology,

impacts, management

– Setting research

agenda

Overview

• Introduction to starry stonewort

• Applied research on starry stonewort

– Risk assessment

– Control

• Takeaways

– Identification

– Citizen science opportunities

Photo: Dan Larkin

Identification

• May grow dense, tall

– Can have robust,

plant-like appearance

underwater

Photo: Paul Skawinski

Identification

• May grow dense, tall

– Can form thick mats

Photos: Dan Larkin,

Minnesota DNR

Identification

• Whorls of 4-6

long branchlets

Photo: Paul Skawinski

Identification

• Small, star-

shaped bulbils

Photos, L-R: Dan Larkin, MN DNR, Paul Skawinski

Volunteer/citizen science opportunities

AIS Detectors AIS Trackers

AIS Detectors program

• Front line for AIS early

detection

• Network of trained

volunteers

• Watershed focus

Sue Galatowitsch (MAISRC Director) and

Eleanor Burkett (Extension Educator)

AIS Trackers program

• Monitoring AIS

population changes in

response to

management

• Use findings to guide

AIS management

Photo: Dan Larkin

Acknowledgments

• Funding: Environment and Natural Resources

Trust Fund

• Collaborators: Luis Escobar, Nick Phelps,

Huijie Qiao

• Undergraduate researcher: Carli Wagner

Photo: Dan Larkin

For more information

MAISRC

• http://www.maisrc.umn.edu

• Sign up for our newsletter

• Follow @AISResearchMN on Twitter

• And like us on Facebook!

Koronis Lake Association (see Kevin Farnum)

• Starry stonewort public information meeting

• Presentation by Prof. John Rodgers, Clemson University

• April 26, 2016 at 7:00 PM

• Paynesville High School Auditorium