Alien Invaders!!

Impacts of Invasive Plant Species in Oregon

Erin Tirone

Road Map

• Definitions• Examples of Invasive Species

– Description– Impacts on native landscape

• Eradication Methods– Pros/cons

• Questions

What does it mean to be…?

• Native– A plant or animal originating from a particular

place or region

• Endemic– Native to or confined to a certain region

• Invasive– Marked by a tendency to spread– Tendency to intrude or encroach

Why do plants become invasive?

• “New” environment similar to native environment

• Better competitors than the natives

• Efficient adaptations

• No natural predators in “new” environment

• Opportunistic

Himalayan Blackberry

• Native to Eurasia, pervasive in Oregon

• Spreads rapidly through underground growth and seed dispersal

• Establishes itself in sunny disturbed areas

English Ivy

• Europe native• Spreads by extension

of runners• Many negative

impacts on plant and habitat diversity

• Attempts at mitigation in Forest Park

Reed Canarygrass

• Native for Europe and Asia (though still being debated whether it is actually native to North America)

• Spreads through rhizomes and seed dispersal

Scotch Broom

• Scotland native• Grows on open,

sunny, disturbed sites• Produced enormous

amount of seeds, which are viable for up to 80 years

Japanese Knotweed

• Introduced from Asia, perhaps as ornamental plant

• Grows through rhizomes

• Establishes itself in moist ravines, ditches, and disturbed areas

Morning Glory

• Eurasian native• Grow in disturbed

areas, commonly found along waterways, fields and roadsides

• Grow from rhizomes, are ground creepers

Clematis

• Common in disturbed open canopy areas

• Spread through wind dispersal of seeds from wispy flowers

Common Methods of Eradication

• Pulling out the roots

• Cutting canes (blackberry)

• Soil solarization

• Planting Native plants

• Herbicide application– Spraying– Spot application

Works Cited

• Invasive and Exotic Species of North America. 2002. USDA Forest Service. http://www.invasive.org

• Invasive Plants--A Guide for Dealing with Non-native Species. Beaverton, OR: Natural Resources Office, Tualatin Hills Park and Recreation District

• Pojar, J. & A. MacKinnon. 1994. Plants of the Pacific Northwest Coast. Vancouver, B.C.: Lone Pine.

• Reed Canyon Enhancement Strategy. Non-native Species Management. 2001. Portland, OR: Reed College. http://web.reed.edu

• Taylor, R.J. 1990. Northwest Weeds. Missoula, MT: Mountain Press.