Transcript Curly Leaf Pondweed Identification

Managing Aquatic Invasives:
Curly-leaf Pondweed
and Eurasian Water Milfoil
Barbara Liukkonen
University of Minnesota Extension
Waconia, April 1, 2008
Key messages
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Ecology of aquatic vegetation
Opportunities for AIS invasion
Unique life history of CLPW
CLPW & EWM identification and lookalikes
Photo, Steve McComas,
Blue Water Science
The Ecology of Aquatic Plants
Photo by Mark Hagley
Why care about aquatic plants?
 Food
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and habitat for:
Waterfowl
Mammals
Fish
Invertebrates
Algae
Fungi
Bacteria
People
University of Wisconsin – Extension
Sediment and erosion control
• Shield shoreline
from erosive wave
action
• Stabilize bottom
sediments
• Help keep water
clear
Spawning, nesting, feeding, and
refuge sites
Mary
Gartshore
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Less obvious reasons to care
about aquatic plants
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They play a critical role in the
ecological functioning and nutrient
cycling of most aquatic systems
Photo, Mark Hagley
Productivity
Oligotrophic – 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 nutrients
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Algaedominated
systems
Blue-green
algae
blooms
increasing –
potentially
toxic
Schwanz Lake, MN
Which would you prefer?
Photo, Rich Axler
How can disrupting the plant
community lead to increased 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 balance
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Disturbances disrupt the
balance
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Excessive nutrients
Mechanical harvester or boat
damage
Herbicides
Grazing by invasive fish
Major storms eroding shorelines
Choices you make can drive
your lake to “algal soup”
E. Burkett, UMES
Disturbance impacts
just like on land
How can disrupting
the native plant
community
contribute to
nuisance aquatic
plant invasions?
Orchard Lake
Photo, Steve McComas,
Blue Water Science
Plant communities
Aquatic plant growth forms
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Floating-leaf
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Submergent
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Emergent
http://aquat1.ifas.ufl.edu/\
Floating leaved plants
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Near-shore unless sheltered
Can grow to 3-6 ft deep
Can grow in turbid water because leaves float
Rooted or floating roots
Water lilies
Watermeal
(Wolffia)
Duckweed
Submerged Aquatics
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Weak-stemmed
Survive below ice & waves
In clear water can grow 6-12 ft below surface
May have floating leaves
Rooted or floating roots.
Milfoil
CLPW
Isoetes (quillwort)
Emergent
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Roots below water surface
Vegetative parts above water
Special respiratory systems to pass
oxygen to roots
Tolerate fluctuating water levels
Dense stands can dampen wave
action
cattails
reeds
bulrushes
Summary – Why is aquatic
vegetation important ?
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Habitat for food
organisms (insects,
invertebrates)
Spawning, nesting,
resting habitat for fish
& wildlife
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Prevent shoreline erosion
Filter nutrients
Stabilize bottom substrates
Add dissolved oxygen to
water
Photo: Mark Hagley
How does curly leaf fit in?
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Submerged plant
VERY well-adapted to
disturbance
Messes up the natural
ecological cycle
Photo, Shannon Lotthammer,
2005, PLSLWD
Curly Leaf Pondweed
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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
Habitat
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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 habitat
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Grows well in
disturbed sites
Can grow under
algae or snowcovered ice
Strong roots allow
growth in lakes or
moderate 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 cycle
Autumn/winter
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Sprouts buds from
turions
Remains alive during
winter
Can grow under ice
Spring
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Rapid growth while
other plants continue
dormancy
J.R. Wehrmeister and R.L. Stuckey. 1992.
Life History of Potamogeton crispus. Mich.
Botanist. 31(1):3-16
summer
spring
fall
winter
Life cycle
Spring/summer
 May form dense
mats
 Flower spikes/seeds
 Turions form in leaf
axils
summer
spring
fall
winter
J.R. Wehrmeister and R.L. Stuckey. 1992.
Life History of Potamogeton crispus. Mich.
Botanist. 31(1):3-16
Life cycle
Summer/fall
 Turions drop
 Disperse by water
movement
 Sink to bottom of
lake
 Lie dormant
 Cycle begins again
J.R. Wehrmeister and R.L. Stuckey. 1992.
Life History of Potamogeton crispus. Mich.
Botanist. 31(1):3-16
summer
spring
fall
winter
CLPW reproduces …
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Through turions
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Through rhizomes
Photo: Barb Liukkonen
Photo: Barb Liukkonen
Potamogeton species
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Species are difficult to identify
Several have oval floating leaves
Others have entire structure below water
In flower, plants have compact spikes with
greenish to brownish flowers above water
surface
Pondweeds grow densely to limit of light
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Three kinds of
pondweed
Note the differences
in appearance
Source: W. Hoagman, 1998. Great Lakes
Wetlands. University of Michigan press
Curly Leaf Identification
Key point # 1
 Leaves grow in an
alternate pattern along the
stem
 Typical in many
pondweeds
Curly Leaf Identification
Key point #2
 Branching vein pattern
 The only pondweed
with branching vein
pattern
Curly Leaf Identification
Key point #3
 Serrated leaf margin
 Only 1 other pondweed
species has serrated
margin
Curly Leaf Identification
Photo, Barb Liukkonen,
Leaves are
wavy and may
be reddish in
color, but this
is not unique to
curly leaf
pondweed
Look-alike plants
Richardson’s pondweed
Potamogeton richardsonii
Curly leaf pondweed
Potamogeton crispis
• Serrated leaf
margin
• Branching vein
pattern
•Smooth leaf margin
• Vein pattern parallel
• Leaf clasps stem
• Leaves not
clasping stem
CLPW
Management
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Physical – drawdown
Biological – no known bio controls yet
Mechanical – harvesting
Chemical – timing and application
critical
CLPW Control
Opportunities
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Control the turions,
control the plant
No growback after 16
nodes
Treat before plant
reaches 22 nodes
Eurasian Water Milfoil
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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 description
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Slender stems whorled by threadlike
leaves
4-petaled/no petal flowers in the axils of
the floral bracts
Fruits are four-jointed nut-like bodies
Reproduces through fragments & runners
USDA-NRCS
PLANTS Database / USDA
NRCS. Wetland flora: Field office illustrated
guide to plant species. USDA Natural
Resources Conservation Service.
USDA-NRCS PLANTS Database/ Britton, N.L.,
and A. Brown. 1913. An illustrated flora of
the northern United States, Canada and the
British Possessions. Vol. 2: 614.
EWM in MN
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200 lakes, as of
summer 2007
Thick mats at
surface
Interferes with
recreation
Takes
advantage of
disturbance
Look-alikes
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Without flowers or fruits, difficult to tell
EWN from Northern water milfoil
EWM - 9-21 pairs of leaflets per leaf
Northern milfoil - 7-11 pairs of leaflets
Coontail is often mistaken for milfoil, but
does not have individual leaflets.
EWM
Management
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Mechanical - harvesting
Biological – weevil
Chemical – timing and application
critical
Biological control
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Euhrychiopsis
lecontei
Native species
Stem “miners”
21-30 day life cycle
Prefer EWM
Cycle with plant
populations, fish
predation
Managing
CLPW &
EWM
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Photo, J. Barton,
Three Rivers
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Photo, B. Rice, TNC
Eradication unlikely
Management and
control are key
Takes coordinated
action, working
together
Partnership –
property owners,
local resources,
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) 3462116
Bald Eagle Lake
Photo, Steve McComas, Blue
Water Science
Special thanks to:
Mary Blickenderfer, UM Extension Service
Eleanor Burkett, UM Extension Service
Wendy Crowell, MN Department of Natural Resources
Cynthia Hagley, MN Sea Grant Program
Photo, Brian Vlach, 2005,
Three Rivers Park District
The information and drawings in this slide show
are copyright by the Board of Regents of the
University of Minnesota, 2008, or by the
sources listed. If you want to reproduce or
reuse them, please contact Barb Liukkonen,
[email protected] from the University of
Minnesota Extension Service.