Invasive PlantsWhat is an invasive plant?Why are these invasive plants such a problem?

What are some common invasive plant species across the country?

What we can do to prevent their spread?

Definition of Invasive Species

• Definition: Non-native or alien species to the ecosystem under consideration and whose introduction does or is likely to cause economic, environmental harm, or harm to human health.

“Alien species" means, with respect to a particular ecosystem, any species, including its seeds, eggs, spores, or other biological material capable of propagating that species, that is not native to that ecosystem.

How did they get here?

Invasive species

• Introduced for food, fiber, pharmaceutical ,and ornamental reasons

• 50,000 invasive plant and animal species are established in the U.S.

• 5000 plant species have escaped and now exist in U.S. natural ecosystems (Morse et al., 1995)

Problems caused by invasive species

• Crowd out native plants and wildlife that depend on them.

• Disrupt ecosystem processes; hydrology natural succession and pollination

• Cause soil erosion and change soil chemistry

• Create additional fire hazard

Problem of Invasive Species

• Invasive plants represent 47% of the total flora of most states. This percentage continues to increase annually (Zheng et al., 2004)

• Cost $138 billion annually in the US (Pimental et al., 2000).

USDA’s budget at $990 million. USACE’s budget at $55 million.

• Approximately 42% of Threatened and Endangered species are at risk because of invasive species (Pimental et al.,2000)

Executive Order 13112Signed by President Clinton, 1999.

• Establishes the National Invasive Species Council. Currently there are 13 Departments and Agencies on the Council.

• Purpose: to prevent the introduction of invasive species and provide for their control and to minimize the economic, ecological, and human health impacts that invasive species cause

• The Council wrote the National Invasive Species Management Plan

Definitions

• "Control" means, as appropriate, eradicating, suppressing, reducing, or managing invasive species populations, preventing spread of invasive species from areas where they are present, and taking steps such as restoration of native species and habitats to reduce the effects of invasive species and to prevent further

invasions.

10 Riparian invasive species

• NE Purple Loosestrife; Japanese Stilt Grass

• SE Kudzu; Japanese Knotweed

• SW Salt Cedar; Giant Reed

• NW Cheat grass; Common Reed

• Country wide: Russian Olive; Autumn Olive

Invasive Plant Species of Arkansas

Purple loosestrife Lythrum salicaria

Purple loosestrife Lythrum salicaria

• Native to Europe, SE Asia, Russia, India

• Listed as a invasive plant in all U.S. states except FL.

• Invades and fills habitat niche and provides no wildlife food value

• Clogs waterways and sends millions of seeds into water system

• Brought here as an ornamental

• Change in nutrient cycling of N and alters wetland function (accelerate eutrophication)

Japanese Stilt Grass Microstegium vimineum

Japanese Stilt Grass Microstegium vimineum

• Native to Asia, introduced 1919• Invasive in 15 eastern states• Carpets the Riparian bottomland with

thick thatch that prohibits the growth of native plants

• It is physiologically adaptive and may alter soil conditions to benefit itself by increasing the pH, nitrification and nitrate

KudzuPueraria montana Var. lobata

Kudzu Pueraria montana var. lobata

• Native to China, introduced in late 1876 at the Philadelphia Centennial Exhibition & promoted as a forage crop. Also planted by the CCC to prevent erosion.

• Invasive in 22 states

Positive growth response to increasing CO2

• Tolerant of nutrient-poor, compacted soils and drought conditions

Japanese Knotweed Fallopia japonica

Japanese Knotweed Fallopia japonica

• Native to Asia, introduced in late 1800’s aws

an ornamental plant.• Invasive to 36 states• Grows in Zones 4 – 8, Herbaceous shrub to

3 m tall • Preference for wet environments, riparian

and disturbed areas• A synonym for this plant (in some Floras) is

Polygonum cuspidatum.

Salt Cedar Tamarix ramosissima

Salt Cedar Tamarix ramosissima Ledebour

• Native to Eurasia and Africa• Small tree, brought in as an ornamental• Noxious weed in 13 western states• Widespread in riparian systems, displacing other

native plants. • Water-use rates of Tamarix are among the highest of

any phreatophyte evaluated in the S.W. and lowers the water table (can consume 4 ac-ft of groundwater annually).

• Increases soil salinity; salts redistributed from deep in the soil to the soil surface which inhibit other plant sp.

Salt Cedar Tamarix ramosissima

Control and Management:• Manual – Digging, root cutting by any

mechanical means, fire and flooding

• Chemical- General use herbicides such as glyphosate or triclopyr; product approved for aquatic application. Follow label and state requirements.

• Biocontrol- 15 insects; a mealybug (Tributina mannipara) and a leaf beetle (Diorhabda elongata) have been released. Leaf Beetle is impacting Endangered Willow Flycatcher habitat. Five other insects are being studied for release in the US.

Giant Reed Arundo donax

Giant Reed Arundo donax

• Native to India and countries around the Mediterranean sea

• Forms dense thickets which chokes riverside and stream channels

• Crowds out native plants and reduces wildlife habitat

• Creates fire hazard• Small plant fragments can travel downstream and

invade new areas

Giant Reed Arundo donax

Control and Management:Manual – Repeat mowing is necessary.

Chemical- General use herbicides such as glyphosate. Apply to clumps after flowering. Prescribed burning alone or in combination with use of herbicide. Follow label and state requirements.

Biocontrol agent from Europe being tested.

Cheatgrass Bromus tectorum

Cheatgrass Bromus tectorum

• Native to Europe, N Africa, SW Asia

• Invasive in 17 states

• Many ecosystems that Cheatgrass has invaded are seriously altered and no longer support the natural plant community and can maintain dominance for many years

• Grows in semi arid environment (10”-22” annual precip.)

• Long awns can pierce animals feet, mouth, nose, eyes and ears

• It is a fuel, creating very hot fires in these grasslands

Cheatgrass Bromus tectorum

Control and Management:Manual – Mowing, grazing, fire and interseeding of competitive native plants

Chemical- General use herbicides such as glyphosate. Follow label and state requirements.

Biocontrol - Pink Snow mold (Fusarium nivale) is being investigated as a control agent.

Common ReedPhragmites australis

Common Reed Phragmites australis

• Native to Europe and the fertile crescent.• Eliminate diverse wetland native plant communities and provides little wildlife food or shelter • Forms dense monoculture stands quickly and

occurs in all 48 continental states.

• It can grow in a wide range of soil conditions: in disturbed area, polluted soils, in somewhat dry sites and in water that is 6 feet deep

Common ReedPhragmites australis

Control and Management:Manual – Mowing may be effective.

Burning plant after it flowers in August-September, but fire will stimulate growth in the Spring.

Chemical - General use herbicides such as glyphosate. Follow label and state requirements.

Biocontrol - No known bio-controls at this time.

Russian Olive Elaeagnus angustifolius

Russian Olive Elaeagnus angustifolius

• Native to southern Europe and western Asia• Invasive in 31 states• Interferes with natural plant succession and nutrient

cycling and tax water reserves

• It is capable of fixing nitrogen and can grow on bare mineral substrate

• Birds will eat berries and spread this tree, however ecologists have found that bird richness is actually higher in riparian areas with native vegetation

Russian Olive Elaeagnus angustifolius

Control and Management:Manual – Mowing hedges with brush type equipment and removal of cut material.

Chemical - General use herbicides such as triclopyr or imazapyr. Also Metasulfuron-methyl with a surfactant is also reported to be effective. After manual process will also need to stump treat with herbicide. Follow label and state requirements.

Biocontrol – None known at this time.

Autumn Olive Elaeagnus umbellata

Autumn Olive Elaeagnus umbellata

• Native to Asia, introduced in the 1830’s.• Invasive to 23 states

• Shrub or small tree, grows in Zones 4 – 8 and spreads extremely rapidly

• Prolific seeding; dispersed by birds and by water. Seed eaten by birds, but not preferentially.

• Can live in a wide range of habitats; tolerant of infertile and dry soils. Can alter nutrient cycling

Autumn Olive Elaeagnus umbellata

Control and Management:Manual – Sprouts pulled by hand. Cutting will result in thicker, denser plants. Burning during the dormant season also results in vigorous re-sprouting.

Chemical- General use herbicides such as glyphosate. Foliar application is effective. This is a nonselective herbicide, so care should be taken with other plants. Follow label and state requirements.

Biocontrol – None known at this time.

Plantwise Guidelines

• Know your plants

• Use non-invasive alternatives

• Watch out for invasive plant hitchhikers

• Be careful if you share plants

• Use only seed mixes that are invasive plant free

Plantwise Guidelines

• Use weed-free soil and mulch mix

• Be especially careful with aquatic plants

• Keep an eye on new sprouts and volunteers

• Dispose of invasive plants carefully

• If you can’t part with your invasive plant, remember – contain it, control it or cage it.

Sources and websites

• http://www.invasivespecies.gov/.

• Plant Management Information System (PMIS)

• Aquatic Plant Information System (APIS)

• http:// na.fs.fed.us/fhp/invasiveplants/weeds/index.shtm

• Huebner C.D. 2007. Invasive Plants Field and Reference Guide. NA-TP-05-04. USDA Forest Service.

• www.invasive.org Invasive Plants of the Eastern United States Identification and control

• Caronann.rifici@us.army.mil (for invasive sp.list serve)

Review

• Definition of invasive species: Non-native or alien species to the ecosystem under consideration and whose introduction does or is likely to cause economic, environmental harm, or harm to human health.

• Invasive plants are a problem because they crowd out native species, do not support our native fauna, cause native species to become threatened and endangered, alter the soil chemistry, alter hydrology and present a fire danger.

• NE Purple Loosestrife; Japanese Stilt Grass

• SE Kudzu; Japanese Knotweed

• SW Salt Cedar; Giant Reed

• NW Cheat grass; Common Reed

• Country wide: Russian Olive; Autumn Olive

Review10 Riparian invasive species

Contact information