aquaticplants_0 by R Wheeler

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 • • • • •

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 • • • • • • • • •

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

ÂŠ2012 Vernon Smith

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

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

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

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 Ă&#x2014; 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 (Nuttallâ&#x20AC;&#x2122;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 VidĂŠki, 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)

Potamogeton robbinsii (Robbins' pondweed)

Zannichellia palustris (horned pondweed)

Ceratophyllum demersum (coontail, hornwort)

• Whorled leaves • Serrated margins • Horn-like divisions

Ranunculus aquatilis (white water buttercup)

ÂŠ 2004, Ben Legler

Cabomba caroliniana (Carolina fanwort)

Isoetes spp. (quillworts)

Isoetes occidentalis

ÂŠ 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 â&#x20AC;˘ 6-16 branchlets, never divided; musky scent, tiny thorn-like projections Nitella â&#x20AC;˘ 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

Brasenia schreberii (water shield)

Eichhornia crassipes (water hyacinth)

Ludwigia palustris (marsh seedbox)

Ludwigia hexapetala, L. peploides (water primrose)

ÂŠ 2005, Ben Legler

Azolla pinnata (feathered water fern)

Other azollas

A. filliculoides

A. mexicana

Emergent Aquatic Plants

Butomus umbellatus (flowering rush)

Aquatic perennial ď ŹMoving down Columbia River from infestation in Montana ď ŹLarge 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 mareâ&#x20AC;&#x2122;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