Download Invasive Plants in Pennsylvania

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A species that arrives in a habitat it had not
previously occupied
Establishes a population that spreads rapidly,
often at the expense of native species
Throughout history of life, species have
spread to new regions but human influence
has increased the dispersal
[1 and 2]
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European colonization
◦ Many species were released by the new settlers
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Agriculture and horticulture
◦ Many have escaped cultivation
◦ Plants were introduced as ornamentals, agricultural
species, soil grasses, or soil stabilizers
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Accidental arrival
◦ Transport is unintentional to the area
◦ Weed seeds are accidentally harvested with
commercial seeds and sown in new locations
◦ Seeds can be transported on traveler’s clothes
[2]
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Invasive species can modify an entire ecosystem
by:
◦ Shading out native species and competing for
resources
 Approximately 42% of federally threatened and
endangered plant and bird species are at risk because of
invasive plants [6]
◦ Hybridizing with native species
 Leads to loss in genetic material
◦ Modifying nutrient regimes and flooding
 Reduces crop and forage quality, alters water retention
[1 & 4]
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Invasive species can modify an entire ecosystem
by:
◦ Threatening agriculture and livestock
 Outcompete crops for soil and water resources
 May poison animals
◦ Reducing recreational opportunities
 Swimming, boating, and fishing can be impacted
[1 &4]
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Absence of specialized insects, diseases, and
foraging animals that would naturally keep the
species controlled
Invasive species may be better suited to taking
advantage of disturbed conditions compared to
native species
Invasive plants often:
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Produce large numbers of new plants each season
Tolerate various weather conditions
Spread easily and efficiently by wind, water, and animals
Grow rapidly
[2 & 3]
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Conifer Trees - 4 species
Herbs - 267 species
Grasses - 67 species
Hardwood Trees - 57 species
Shrubs - 61 species
Vines - 39 species
[1]
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Yellow toadflax
Common St. Johnswort
Queen Anne's lace, wild carrot
Hairy galinsoga
Common velvetgrass
Oxeye daisy
Black medic
Yellow sweetclover
Timothy
Buckhorn plantain
[1]
[8]
Linaria vulgaris
Yellow Toadflax
[9]
Hypericum perforatum
Common St. Johnswort
[10]
Daucus carota
Queen Anne's lace, wild carrot
[11]
Galinsoga quadriradiata
Hairy galinsoga
[9]
[12]
Holcus lanatus
Common velvetgrass
Chrysanthemum leucanthemum
Oxeye daisy
[14]
[13]
Medicago lupulina
Black medic
Melilotus officinalis
Yellow sweetclover
[16]
Phleum pratense
Timothy
[15]
Plantago coronopus
Buckhorn plantain
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Prevent
Eradicate
◦ More feasible if done in a restricted area
◦ Establish regular monitoring programs
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Control
◦ Chemical
 Environmentally safe herbicides
◦ Mechanical
 Physically remove invasive plants or change habitat conditions
◦ Biological
 Introduce a natural enemy
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Restoration
◦ Prevent reinvasion by restoring native communities
[7]
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Overview
◦ Observe various plots of land and record how many
invasive species are present and the number of
each
◦ Evaluate the impact the invasive species will have in
that area
◦ Create methods to reduce the number of invasive
species
◦ Educate others
Go back to ‘Invasive Plants of PA’ - Activity
section for more information
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[1] USDA- Natural Resources Conservation Service. Invasive and Noxious
Weeds. Assessed from:
http://plants.usda.gov/java/noxious?rptType=State&statefips=42
[2] Primack, R. 2010. Essentials of Conservation Biology, 5th ed. Sinauer
Associates, Sunderland, MA.
[3] The United States National Arboretum. 2009. Invasive Plants. Accessed
from: http://www.usna.usda.gov/Gardens/invasives.html
[4] US Fish and Wildlife Service. Volunteers and Invasive Plants. 2008.
Accessed from:
http://www.fws.gov/invasives/volunteersTrainingModule/nwrsystem/invasiv
es.html
[5] Sodhi, N. and Ehrlich, P. 2010. Conservation Biology for All. Accessed
online at http://www.mongabay.com/conservation-biology-for-all.html
[6] Pimentel D, Lach L, Zuniga R, Morrison D. 2005. Update on the
environmental and economic costs associated alien-invasive species in the
United States. Ecological Economics 52:273-288.
[7] Ecological Society of America. 2004. Invasive Species. Accessed from :
http://www.esa.org/education/edupdfs/invasion.pdf
Images
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[8] http://www.invasivespeciesinfo.gov/plants/yellowtoadflax.shtml
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[9] http://www.fs.fed.us/r9/wildlife/nnis/herbicide_project/
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[10] http://plants.usda.gov/java/profile?symbol=DACA6
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[11] http://pestid.msu.edu/WeedsPlantIdentification/Hairygalinsoga/tabid/177/Default.aspx
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[12] http://plants.usda.gov/java/profile?symbol=HOLA&photoID=hola_006_avp.tif
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[13] http://plants.usda.gov/java/profile?symbol=MELU&photoID=melu_003_avp.tif
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[14] http://plants.usda.gov/java/profile?symbol=MEOF&photoID=meal12_1h.jpg
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[15] http://plants.usda.gov/java/profile?symbol=PHPR3&photoID=phpr3_002_avp.tif
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[16] http://plants.usda.gov/java/nameSearch