Managing Aquatic Invasives: Managing Aquatic Invasives: Curly-leaf PondweedCurly-leaf Pondweed

and Eurasian Water Milfoiland Eurasian Water Milfoil

Barbara LiukkonenUniversity of Minnesota Extension

Waconia, April 1, 2008

Key messagesKey messages

Ecology of aquatic vegetationEcology of aquatic vegetation Opportunities for AIS invasionOpportunities for AIS invasion Unique life history of CLPWUnique life history of CLPW CLPW & EWM identification and look-CLPW & EWM identification and look-

alikesalikes

Photo, Steve McComas, Blue Water Science

The Ecology of Aquatic The Ecology of Aquatic Plants Plants

Photo by Mark Hagley

Why care about aquatic Why care about aquatic plants?plants?

Food and habitat for:Food and habitat for: WaterfowlWaterfowl MammalsMammals FishFish InvertebratesInvertebrates AlgaeAlgae FungiFungi BacteriaBacteria PeoplePeople

University of Wisconsin – ExtensionUniversity of Wisconsin – Extension

Sediment and erosion Sediment and erosion controlcontrol

• Shield shoreline from erosive wave action

• Stabilize bottom sediments

• Help keep water clear

Spawning, nesting, feeding, Spawning, nesting, feeding, and refuge sitesand refuge sites

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Mary Mary GartshoreGartshore

Less obvious reasons to Less obvious reasons to care about aquatic plantscare about aquatic plants

They play a They play a critical rolecritical role in the in the ecological functioning and nutrient ecological functioning and nutrient cycling of most aquatic systemscycling of most aquatic systems

Photo, Mark Hagley

ProductivityProductivityOligotrophic – low nutrients, low “productivity,” usually high clarity

Mesotrophic – moderate nutrients, moderate “productivity,” moderate clarity

Eutrophic – high nutrients, high “productivity,” low clarity

Diagrams by Cindy Hagley

Influence of excess Influence of excess nutrientsnutrients

Algae-Algae-dominated dominated systemssystems

Blue-green Blue-green algae algae blooms blooms increasing – increasing – potentially potentially toxictoxic

Schwanz Lake, MN

Which would you prefer?Which would you prefer?

Photo, Rich Axler

How can disrupting the plant How can disrupting the plant community lead to increased community lead to increased

algae?algae?Nutrients no longer used by macrophytes are available for algae growth

Algae blooms reduce light for rooted vegetation

Cindy Hagley

Cindy Hagley

A fine ecological balanceA fine ecological balance

Disturbances disrupt the Disturbances disrupt the balancebalance Excessive nutrientsExcessive nutrients Mechanical harvester or boat Mechanical harvester or boat

damagedamage HerbicidesHerbicides Grazing by invasive fishGrazing by invasive fish Major storms eroding Major storms eroding

shorelinesshorelines Choices you make can Choices you make can

drive your lake to “algal drive your lake to “algal soup”soup”

E. Burkett, UMES

Disturbance impacts

just like on land

How can disrupting the native plant community contribute to nuisance aquatic plant invasions?

Photo, Steve McComas, Blue Water Science

Orchard Lake

Plant communitiesPlant communities

Aquatic plant growth formsAquatic plant growth forms

http://aquat1.ifas.ufl.edu/\

Floating-leaf Floating-leaf

SubmergentSubmergent

EmergentEmergent

Floating leaved plantsFloating leaved plants Near-shore unless shelteredNear-shore unless sheltered Can grow to 3-6 ft deepCan grow to 3-6 ft deep Can grow in turbid water because leaves Can grow in turbid water because leaves

floatfloat Rooted or floating rootsRooted or floating roots

Water liliesWatermeal (Wolffia) Duckweed

Submerged AquaticsSubmerged Aquatics Weak-stemmedWeak-stemmed Survive below ice & wavesSurvive below ice & waves In clear water can grow 6-12 ft below In clear water can grow 6-12 ft below

surfacesurface May have floating leavesMay have floating leaves Rooted or floating roots.Rooted or floating roots.

Milfoil

Isoetes (quillwort)CLPW

EmergentEmergent Roots below water surfaceRoots below water surface Vegetative parts above waterVegetative parts above water Special respiratory systems to Special respiratory systems to

pass oxygen to rootspass oxygen to roots Tolerate fluctuating water levelsTolerate fluctuating water levels Dense stands can dampen wave Dense stands can dampen wave

actionaction

cattails

reeds

bulrushes

Summary – Why is aquatic Summary – Why is aquatic vegetation important ?vegetation important ?

Prevent shoreline erosion Filter nutrients Stabilize bottom

substrates Add dissolved oxygen to

water

Habitat for food organisms (insects, invertebrates)

Spawning, nesting, resting habitat for fish & wildlife

Photo: Mark Hagley

How does curly leaf fit in?How does curly leaf fit in?

Submerged plantSubmerged plant VERY well-adapted to VERY well-adapted to

disturbance disturbance Messes up the natural Messes up the natural

ecological cycleecological cycle

Photo, Shannon Lotthammer, 2005, PLSLWD

Curly Leaf Pondweed Non-native, “Exotic” Aquatic Invasive Species or AIS Submergent aquatic plant Potamogeton crispus Similar to other pondweeds Can be very invasive

Photo, Brian Vlach, 2005, Three Rivers Park District

Curly-leaf pondweed in 800+ sites

Distribution of CLPW in Minnesota

as of 2005

HabitatHabitat Deep water plant Colonizes water 1–2 feet deep Spreads to depths of 10 or more

feet Tolerates low light

Photo, John Barten, 2005, Three Rivers Park District

Growth habitatGrowth habitat Grows well in Grows well in

disturbed sitesdisturbed sites Can grow under Can grow under

algae or snow- or snow-covered icecovered ice

Strong roots allow Strong roots allow growth in lakes or growth in lakes or moderate streamsmoderate streams

Photo, Steve McComas, Blue Water Science

Curly-leaf Life Cycle

Its unique life cycle gives curly leaf a

competitive advantage over

many other aquatic plants

Photo: Brian Vlach, 2005, Three Rivers Park District

Life cycleLife cycleAutumn/winterAutumn/winter Sprouts buds from Sprouts buds from

turionsturions Remains alive during Remains alive during

winterwinter Can grow under iceCan grow under ice

SpringSpring Rapid growth while Rapid growth while

other plants continue other plants continue dormancydormancy

J.R. Wehrmeister and R.L. Stuckey. 1992. Life History of Potamogeton crispus. Mich. Botanist. 31(1):3-16

summer

fallspring

winter

Life cycleLife cycle

Spring/summerSpring/summer May form dense May form dense

matsmats Flower Flower

spikes/seedsspikes/seeds Turions form in Turions form in

leaf axilsleaf axils

summer

fallspring

winter

J.R. Wehrmeister and R.L. Stuckey. 1992. Life History of Potamogeton crispus. Mich. Botanist. 31(1):3-16

Life cycleLife cycle

J.R. Wehrmeister and R.L. Stuckey. 1992. Life History of Potamogeton crispus. Mich. Botanist. 31(1):3-16

summer

fallspring

winter

Summer/fallSummer/fall Turions drop Turions drop Disperse by water Disperse by water

movementmovement Sink to bottom of Sink to bottom of

lakelake Lie dormantLie dormant Cycle begins Cycle begins

againagain

CLPW reproduces …CLPW reproduces … Through turionsThrough turions

Through rhizomesThrough rhizomes

Photo: Barb Liukkonen

Photo: Barb Liukkonen

Potamogeton speciesPotamogeton species Species are difficult to identifySpecies are difficult to identify Several have oval floating leavesSeveral have oval floating leaves Others have entire structure below waterOthers have entire structure below water In flower, plants have compact spikes with In flower, plants have compact spikes with

greenish to brownish flowers above water greenish to brownish flowers above water surfacesurface

Pondweeds grow densely to limit of lightPondweeds grow densely to limit of light

Three kinds of Three kinds of pondweedpondweed

Note the Note the differences in differences in appearanceappearance

Source: W. Hoagman, 1998. Great Lakes Wetlands. University of Michigan press

Curly Leaf IdentificationCurly Leaf IdentificationKey point # 1Key point # 1 Leaves grow in an Leaves grow in an

alternate pattern along alternate pattern along the stemthe stem

Typical in many Typical in many pondweedspondweeds

Curly Leaf IdentificationCurly Leaf IdentificationKey point #2Key point #2 Branching vein Branching vein

patternpattern The only pondweed The only pondweed

with branching vein with branching vein patternpattern

Curly Leaf IdentificationCurly Leaf IdentificationKey point #3Key point #3 Serrated leaf marginSerrated leaf margin Only 1 other Only 1 other

pondweed species pondweed species has serrated marginhas serrated margin

Curly Leaf IdentificationCurly Leaf Identification

Leaves are Leaves are wavy and wavy and may be may be reddish in reddish in color, but this color, but this is not unique is not unique to curly leaf to curly leaf pondweedpondweed

Photo, Barb Liukkonen,

Look-alike plantsLook-alike plantsCurly leaf pondweedPotamogeton crispis

•Smooth leaf margin

•Vein pattern parallel

• Leaf clasps stem

Richardson’s pondweedPotamogeton richardsonii

• Serrated leaf margin

• Branching vein pattern

• Leaves not clasping stem

CLPW Management

Physical – drawdown Biological – no known bio controls yet Mechanical – harvesting Chemical – timing and application

critical

CLPW Control CLPW Control OpportunitiesOpportunities

Control the turions, Control the turions, control the plantcontrol the plant

No growback after No growback after 16 nodes16 nodes

Treat before plant Treat before plant reaches 22 nodesreaches 22 nodes

Eurasian Water Milfoil

Submersed aquatic native to Europe, Asia, N. Africa

First in US between 1880 & 1940s In MN in 1987 – Minnetonka Burandt Lake in 2003 Spreads through human activities

and connected waters

Photo by RL Johnson, Cornell University

EWM descriptionEWM description

Slender stems whorled by threadlike Slender stems whorled by threadlike leavesleaves

4-petaled/no petal flowers in the axils 4-petaled/no petal flowers in the axils of the floral bractsof the floral bracts

Fruits are four-jointed nut-like bodiesFruits are four-jointed nut-like bodies Reproduces through fragments & Reproduces through fragments &

runnersrunners

USDA-NRCS PLANTS Database/ Britton, USDA-NRCS PLANTS Database/ Britton, N.L., and A. Brown. 1913. N.L., and A. Brown. 1913. An illustrated An illustrated flora of the northern United States, flora of the northern United States, Canada and the British PossessionsCanada and the British Possessions. . Vol. 2: 614.Vol. 2: 614.

USDA-NRCS PLANTS Database / USDA USDA-NRCS PLANTS Database / USDA NRCS. NRCS. Wetland flora: Field office Wetland flora: Field office illustrated guide to plant speciesillustrated guide to plant species. USDA . USDA Natural Resources Conservation Service.Natural Resources Conservation Service.

EWM in EWM in MNMN

200 lakes, as of 200 lakes, as of summer 2007summer 2007

Thick mats at Thick mats at surfacesurface

Interferes with Interferes with recreationrecreation

Takes Takes advantage of advantage of disturbancedisturbance

Look-alikesLook-alikes

Without flowers or fruits, difficult to Without flowers or fruits, difficult to tell EWN from Northern water milfoiltell EWN from Northern water milfoil

EWM - 9-21 pairs of leaflets per leafEWM - 9-21 pairs of leaflets per leaf Northern milfoil - 7-11 pairs of leafletsNorthern milfoil - 7-11 pairs of leaflets

Coontail is often mistaken for milfoil, Coontail is often mistaken for milfoil, but does not have individual leaflets.but does not have individual leaflets.

EWM Management

Mechanical - harvesting Biological – weevil Chemical – timing and application

critical

Biological Biological controlcontrol

Euhrychiopsis lecontei

Native species Stem “miners” 21-30 day life cycle Prefer EWM Cycle with plant

populations, fish predation

Managing Managing CLPW & CLPW &

EWMEWM Eradication unlikelyEradication unlikely Management and Management and

control are keycontrol are key Takes coordinated Takes coordinated

action, working action, working togethertogether

Partnership – Partnership – property owners, property owners, local resources, local resources, DNRDNR

Photo, J. Barton, Three Rivers

Photo, B. Rice, TNC

Recommended Reading: Recommended Reading: A field Guide to identification of Minnesota

Aquatic Plants, by M. Blickenderfer (2007) Through the Looking Glass: A Field Guide to

Aquatic Plants by Borman, S., Korth, R. & Tempte, J. (1997). Available from Wisconsin Lakes Partnership at (715) 346-2116

Special thanks to:Mary Blickenderfer, UM Extension ServiceEleanor Burkett, UM Extension ServiceWendy Crowell, MN Department of Natural ResourcesCynthia Hagley, MN Sea Grant Program

Bald Eagle LakePhoto, Steve McComas, Blue Water Science

The information and drawings in this slide show The information and drawings in this slide show are copyright by the Board of Regents of the are copyright by the Board of Regents of the University of Minnesota, 2008, or by the University of Minnesota, 2008, or by the sources listed. If you want to reproduce or sources listed. If you want to reproduce or reuse them, please contact Barb Liukkonen, reuse them, please contact Barb Liukkonen, liukk001@umn.eduliukk001@umn.edu from the University of from the University of Minnesota Extension Service.Minnesota Extension Service.

Photo, Brian Vlach, 2005, Three Rivers Park District