Download Invasive Aquatic Plants

Invasive Aquatic Plants
Identifying Known & Potential Weeds in the PNW
Oregon Lake Watch
Center for Lakes and Reservoirs
Overview
• Impacts – why aquatic weeds matter?
• Growth forms
– Submerged
– Floating-leaf
– Emergent (shoreline)
• Aquatic plants, including
– Common invasives
– New (high priority) invasives
– Common native look-alikes
• Importance of confirmation & reporting
Ecological Impacts
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Reduce light penetration & mixing
Reduce species diversity
Alter temperature, dissolved oxygen & pH
Degrade fish habitat
Altered nutrient cycling
Economic Impacts
• Reduce flow in irrigation canals and drainage ditches
– Increased cost of irrigation
– Flooding
– Clogged pumps & intake structures
• Loss of recreational resources
• Negative impacts on property values
Photo: Bridgetotrade.net
Photo: Enviroscience, Inc
Human Health and Safety
Growth forms
How do aquatic weeds move and
spread?
Invasive plants and animals have
spread to new areas due to:
boats and trailers
bait buckets
water movement
Osceola County, Hydrilla Dem. Proj.
(waves, downstream movement)
waterfowl & other animals
PSU-CLR
Aquatic plants can reproduce & spread by:
plant fragments
www.brantlakemilfoil.org
seed
tubers
turions
Rich Miller, PSU-CLR
www.birdphotos.com
Submerged
Aquatic Plants
Eurasian watermilfoil
(Myriophyllum spicatum)
a.k.a. “EWM”
EWM Habitats & Growth
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Lakes, reservoirs, ponds, rivers, and streams
Fresh to brackish water (up to 15 ppt)
Depth: (0.5) 1-5 (10) meters
pH range: 5.4 to 11
Fine-textured, inorganic sediment
Early & rapid spring growth (water temp >15 ͦ C )
Tops out in water < 5 m
Autofragmentation in fall/early winter
Overwintering root crowns
Other Myriophyllum spp.
Whorled watermilfoil
(M. verticillatum)
Andean watermilfoil
(M. quitense)
J. Parsons, WA DOE
A. Hipp, U of WI-Stevens Point
©2012 Vernon Smith
V. Morgan, PSU-CLR
V. Morgan, PSU-CLR
Northern watermilfoil
(M. sibiricum)
Identification of Eurasian milfoil
• 4 leaves per whorl
• 14 or more leaflet pairs
• leaves more squared in
outline
• collapse more when out of
the water
• no winter buds
Hybrid watermilfoil
(M. spicatum × sibiricum)
michiganlakeinfo.com
Variable-leaf watermilfoil
(M. heterophyllum)
V. Morgan, PSU-CLR
L.J. Mehrhoff, U of CT, Bugwood.org
© 2014 Donald Cameron
L.J. Mehrhoff, U of CT, Bugwood.org
Milfoil Character Comparison
submerged leaves
Status in PNW # leaflet pairs
leaf size
leaves/whorl
emergent leaves (bracts)
winter buds (turions)
Northern watermilfoil
(Myriophyllum sibiricum)
NATIVE
<14 (5-14) < 4 cm long
3 to 5
reduced (1-3 mm long);
smaller than flowers
yes
whorled watermilfoil
(Myriophyllum
verticillatum)
NATIVE
<14 (5-14) < 5 cm long
4 to 5
2-10 mm long;
deeply pinnately lobed
yes
Andean watermilfoil
(Myriophyllum quitense)
NATIVE
2 to 5
0.5-1 cm long;
partially toothed
yes
no
Parrot feather
(M. aquaticum)
INVASIVE
Eurasian watermilfoil
(M. spicatum)
INVASIVE
5-10
1.5 - 4 cm
long
10-15
1.5 - 3.5 cm
long
3 to 6
2-5 cm long; 16-18 leaflet
pairs
stiff, waxy, bright green
> 14 (12-24) 2 - 4 cm long
3 to 6
reduced (1-3 mm long);
smaller than flowers
no
yes
?
Variable-leaf watermilfoil
(M. heterophyllum)
INVASIVE
5-12
2-4 cm long
4 to 6
0.5 - 3 cm long;
larger than flowers;
serrated/lobed
Hybrid watermilfoil
(M. spicatum × sibiricum)
INVASIVE
8-19
1.5-4.2 cm
long
?
?
Hydrilla verticillata
(hydrilla)
Hydrilla Distribution
• Map of ID and WA and
Monecious
• eddmapp
Dioecious
Primarily
dioecious
Other Hydrocharitaceae
Elodea canadensis
(Canadian waterweed)
Elodea nutallii
(Nuttall’s waterweed)
Egeria densa
(Brazilian elodea)
Differentiating the Hydrocharitaceae
Elodea sp.
Egeria
Hydrilla
(Native)
(Non-native,
common in OR/WA)
(Non-native,
unknown in OR)
Robert Vidéki, Doronicum Kf
Bugwood.org
Potamogeton crispus
(curly leaf pondweed)
Sastramoutomo 1981
Stuckenia pectinatus
(sago pondweed)
Other Potamogetonaceae
Potamogeton foliosus
(leafy pondweed)
Potamogeton richardsonii
(Richardson’s pondweed)
P. pusillus
(small pondweed)
© 2012, Craig Althen
Potamogeton robbinsii
(Robbins' pondweed)
© 2005, Ben Legler
© 2005, Ben Legler
Zannichellia palustris
(horned pondweed)
© 2005, Ben Legler
Ceratophyllum demersum
(coontail, hornwort)
• Whorled leaves
• Serrated margins
• Horn-like divisions
Ranunculus aquatilis
(white water buttercup)
© 2004, Ben Legler
Cabomba caroliniana
(Carolina fanwort)
Isoetes spp. (quillworts)
Isoetes occidentalis
© 2010, G. D. Carr
Isoetes nuttallii
Utricularia spp. (bladderworts)
Utricularia vulgaris
(common bladderwort)
Utricularia inflata
(swollen bladderwort)
Callitriche heterophyllum
(different-leaved water-starwort)
Callitriche stagnalis
(pond water-starwort)
Callitriche hermaphroditica
(northern water-starwort)
Callitriche palustris
(vernal water-starwort)
Macroalgae
Chara spp.
(muskgrasses)
Chara
• 6-16 branchlets,
never divided;
musky scent, tiny
thorn-like
projections
Nitella
• 6-8 evenly
forked branchlets;
no scent; smooth
texture
Nitella spp.
(brittlewort)
Floating Leaf
Aquatic Plants
Nymphaea odorata
(fragrant water lily)
• Rooted aquatic perennial
• 3-6 feet
• Floating heart-shaped or
circular leaves (30 cm);
purplish underneath,
leathery, deeply cordate
• Large (6-12 cm) fragrant
flowers; 20-30 petals,
range of colors with
yellow centers
Nuphar lutea
(yellow pond-lily )
• Larger, oval to heart-shaped
leaves with a prominent
midvein
• Flowers – yellow petals
and centers, 9-petals
Nymphoides peltata
(yellow floating heart)
• Aquatic perennial
• Depths of 2-13 feet.
• Leaves heart-shaped to circular,
1 to 4 in long, purplish
underneath with slightly wavy
margins
• 5-petaled, 1-1.25” diameter
© 2004, Sue Winterowd:
Brasenia schreberii
(water shield)
Eichhornia crassipes
(water hyacinth)
Ludwigia palustris
(marsh seedbox)
Ludwigia hexapetala, L. peploides
(water primrose)
© 2005, Ben Legler
Azolla pinnata
(feathered water fern)
Other azollas
A. filliculoides
A. mexicana
Emergent
Aquatic Plants
Butomus umbellatus
(flowering rush)
Aquatic perennial
Moving down Columbia
River from infestation in
Montana
Large infestation in
Yakima River
Butomus umbellatus
(flowering rush)
• Cluster of 20-50 flowers
with 3 pinkish petals and
sepals.
• Leaves triangular at base,
flattened above, but
strong mid-rib.
• Emergent leaf tips may be
spirally twisted
• Submersed leaves long,
strap-like.
• Strongly rhizomatous
Phragmites australis
(common reed)
ssp. australis
ssp. americanus
Phragmites Distribution in the Columbia
Basin
Green = native
Red = introduced
Warrenton, OR
Typha spp. (cattail)
T. angustifolia
(narrow-leaf cattail)
T. latifolia
(broad-leaf cattail)
Invasives
Lythrum salicaria
(purple loosestrife)
Lysimachia vulgaris
(garden loosestrife)
Phalaris arundinacea
reed canary grass
ribbon grass
Iris pseudacorus (yellow-flag)
Myrophyllum aquaticum
(parrot feather)
Hippuris vulgaris
(common mare’s tail)
Importance of Reporting &
Confirmation
Many factors can complicate accurate
identification, such as:
• confusion with closely-related native species
• hybrids (milfoils, pondweeds, etc.);
• plasticity – physical characteristics (leaf shape
or color) may vary due to environmental
conditions
Suspected weeds should be
reported ASAP!
Delayed reporting/confirmation can result in:
higher management costs
reduced chances of eradication
(Rejmanek and Pitcairn, 2002)
Remember, weeds are not alone out there!
Zebra and Quagga mussels
Dreissena sp.
• The name derives from stripes on the
shell…
• However you won’t always see black and
white stripes
REPORT THIS SPECIES ASAP!
Report Suspected AIS
oregoninvasiveshotline.org
or call 1-866-INVADER
www.pdx.edu/oregon-lake-watch
503-725-2937 or 503-725-9075