Diversity of Approaches Diversity of Approaches Controlling Invasive SpeciesControlling Invasive Species

• Controlling invasives is not simply :”Spray and Pray”

• Examples of the range of approaches for control of invasivesExamples of the range of approaches for control of invasives::

– Taking advantage of Taking advantage of physiological vulnerabilityphysiological vulnerability- - Amur HoneysuckleAmur Honeysuckle

– Timed mowing or physical removalTimed mowing or physical removal- - Garlic MustardGarlic Mustard

– Restoring stressed ecosystemsRestoring stressed ecosystems- - Reed CanarygrassReed Canarygrass

– Aerial photography to locate populations- distinctive color, textureAerial photography to locate populations- distinctive color, texture

– Pretreatment to Pretreatment to increase vulnerability to herbicidesincrease vulnerability to herbicides- - Reed CanarygrassReed Canarygrass

– Identify factors that lead to invasivenessIdentify factors that lead to invasiveness- - Callery PearCallery Pear

– Selective herbicide to release native speciesSelective herbicide to release native species- - Tall FescueTall Fescue

– Use of Use of herbivorous insectsherbivorous insects- - Purple LoosestrifePurple Loosestrife1

1975

1986

1992

Phenology of rootcarbohydrate cycling

wood formation

starch accumulationbuildup of black

spring sugar supply

Wargo 1979 Can J For Res 9: 49-56

– Starch forms

during the seasons

of active photo-

synthesis

Seasonal Seasonal MetabolismMetabolism

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– Starch

Breaks down

in spring in

support of

bud break

Phenology of shoot carbohydrate cycling in Salix spSauter and Wellenkamp 1998 Holzforschung 52: 255-262

Seasonal MetabolismSeasonal Metabolism

1.See previous slide

2.4. 3.3.xylem sap dormant storagegrow stems, budsdorm metab dormant metabolism

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Taking Advantage of Taking Advantage of Physiological Physiological VulnerabilityVulnerability- Amur Honeysuckle- Amur Honeysuckle

– Apply Roundup in late fall so it is translocated in dormant wood.

– Glyphosate kills the cells that store starch and sugar for spring leaf-out

– No leaves form in spring and the honeysuckle dies.

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Season Stage of Growth

early spring mobilization of stored organic

nutrients into growth of new shoots

late spring / early summer leaf and bud growth slows as shoot

reaches maturity; winter buds

late summer / early fall formation of stem carbon stores

late fall reclaiming of organic nutrients from

leaves - storage in dormant wood

Restoring EcosystemsRestoring Ecosystems- - Bush HoneysuckleBush Honeysuckle

• Management programs are an integral to invasive control.

• Understory is managed to encourage forest floor re-vegetation.

• Shrubs are planted to replace honeysuckle, especially at woodland edges

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Managed

Unmanaged

March

April

June

Restoring Stressed EcosystemsRestoring Stressed Ecosystems- - Reed CanarygrassReed Canarygrass

• Reed canarygrass is more salt tolerant than the native Carex stricta, tussock sedge. (Prasser and Zedler 2010)

• Road salts could contribute to the observed replacement of the tussock sedge by the invasive reed canary grass.

• Management programs that do not address the runoff will not succeed in the long term.

• Understory is managed to encourage forest floor re-vegetation.

• Shrubs are planted to replace honeysuckle, especially at woodland edges

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Increase Vulnerability to Herbicde- Increase Vulnerability to Herbicde- Reed CanarygrassReed Canarygrass

– See journal article:See journal article:

Annan CA 2010 Prospects for disrupting rhizome apical dominance prior to chemical treatment of Phalaris arundinacea. Ecological Restoration 28:291-298

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Timed Mowing or Physical RemovalTimed Mowing or Physical Removal- - Garlic MustardGarlic Mustard

• Control is initiated when the plants are nearly finished flowering.

• Flower heads are removed with a string weed cutter or a weed saw.

• Bolting second year garlic mustard plants are trimmed when the last flowers at the tip are maturing, generally in early May.

• Since the living cells and sap present in the thick stalks can supply nutrients that enable seeds to mature even after the plant has been cut down, the top of the stalk with seed heads is first cut off several inches below the tip with the weed saw and then cut again just below the lowest flowers.

• A final cut at the base of the plant takes the plant to the ground.

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Identify Factors that Lead to InvasivenessIdentify Factors that Lead to Invasiveness- - Callery PearCallery Pear

• The cultivars are self sterile.

• When introduction of many new cultivars to replace Bradford pear which is prone to splitting in snowfalls enables all the cultivars to bear fruit and seeds.

• The trees now spread prolifically by seed. Fruits are distributed by starlings causing widespread distribution of seedlings in old fields, prairies, wetlands and along roads and woodland edges

• Areas in our parks, roadsides and countysides are being invaded by young callery pear trees. The impressive site of these springtime flowering trees has led to extensive use for ornamental plantings

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Selective Herbicide to Release Native Species- Selective Herbicide to Release Native Species- Tall FescueTall Fescue

– See journal article:See journal article:

Annan CA 2010 Prospects for disrupting rhizome apical dominance prior to chemical treatment of Phalaris arundinacea. Ecological Restoration 28:291-298

• Treating areas of tall fescue with a selective grass herbicide releases native species to grow up and replace the forage grass.

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