Download Invasive Plants and Weeds

Invasive Plants and Weeds
Why Care?
The spread of noxious weeds:
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Signal the decline of entire ecological watersheds.
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Severely impact the beauty and biodiversity of natural areas
and cause widespread economic losses.
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Problem for urban as well as rural areas, and for private,
state, and federal lands.
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Noxious weed species spare no segment of society—rancher,
farmer, fisher, and cycler alike
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Can’t leave well enough alone - when unmanaged, they
spread rapidly, unceasingly, and silently
Exotic Invasive Species
– more than just plants
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plants
animals
microbes (fungi, bacteria, etc.)
viruses (i.e., diseases)
Plant Terminology
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Native
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Introduced
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?
Invasive
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?
?
Weed
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?
Native on Indigenous
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Originated where they now occur without the
help of humans.
For example, native to North America
Well adapted to the local climate, soils,
animals, and microbes.
How long have they
been here?
Western Yarrow - Native plant widely
distributed throughout North America
Introduced, Exotic or Non-native
http://www.youtube.com/watch?feature=player_profilepage&v=eDji4I1v4-E#!
Introduced, Exotic or Non-native
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An organism occurring outside of its natural
home range
Other names include alien, foreign, nonindigenous
Introduced by humans
Alien Plants –Mississippi Valley Example
http://www.youtube.com/watch?v=Brb3ES5aOcY&feature=related
Introduced, Exotic or Non-native
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Humans introduced non-native plants as:
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Grains and food crops
Seeds in Ship Ballast
Ornamentals
Plants for erosion control
Plants with higher forage value
Accidental
Introductions of exotics continues today
Invasive Species
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An organism that spreads and establishes
over large areas and persists
Growth characteristics that allow it to
dominate the ecosystem
Invasive Species Website =
http://www.invasivespeciesinfo.gov/
Invasive Species
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Often non-native (or alien) to the ecosystem
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Not all non-natives are invasive
Whose introduction causes or is likely to cause
economic or environmental harm or harm to human
health.
Cheatgrass
Juniper
Characteristics of Invasive Plants
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Abundant seed producers
Rapid population establishment
Long-term survival of seeds
Occupy disturbed sites
Competitive
Lack of natural enemies
Cheatgrass
Juniper
Weed
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Plant of little value or a plant “out of place”
Competes with crops and native species
Troublesome pest that affects the health an
productivity of native landscapes
“a plant whose virtues have not yet been discovered”...
Ralph Waldo Emerson
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“plants that interfere with the growth of desirable
plants and that are unusually persistent and pernicious.
They negatively impact human activities and as such
are undesirable” Ross & Lembi – Applied Weed Science. 1999
Impacts of Weeds
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Reducing biological diversity
Altering hydrologic conditions
Altering soil characteristics
Altering fire intensity and frequency
Interfering with natural succession
Competing for native pollinators
Replacing complex communities with monocultures
Displacing rare plant species
Noxious Weeds
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Noxious = plant species that
have been designated
“noxious” by law.
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The word “noxious” simply means
deleterious
Weeds are declared noxious by
states or counties.
In Idaho, hundreds of weed
species exist. However, only 36
are designated noxious by Idaho
law.
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http://info.ag.uidaho.edu/pdf/BUL/BUL816.pdf
Plant Terminology
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Native
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Introduced
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Introduced by humans, exotic or not native
Invasive
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Originated where they now occur without the help of
humans
Growth characteristics that allow it to spread and dominate
the ecosystem
Weed
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Troublesome pest that affects the health an productivity of
native landscapes
Noxious Weeds = designated “noxious” by lay
Weed Control Approaches
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Chemical
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Mechanical
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Biological
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Cultural
Weed Control Approaches
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Chemical – herbicides to reduce or prevent
weeds
Mechanical
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Biological
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Cultural
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Weed Control Approaches
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Chemical – herbicides to reduce or prevent
weeds
Mechanical – removal or damage to weeds
with physical/mechanical forces
Biological
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Cultural
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Weed Control Approaches
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Chemical – herbicides to reduce or prevent
weeds
Mechanical – removal or damage to weeds
with physical/mechanical forces
Biological – suppress weeds with living
organisms including parasites or pathogens
Cultural
Weed Control Approaches
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Chemical – herbicides to reduce or prevent
weeds
Mechanical – removal or damage to weeds
with physical/mechanical forces
Biological – suppress weeds with living
organisms including parasites or pathogens
Cultural – alter agricultural practices
(fertilize, cultivate, graze) to
suppress weeds
Weed Control Approaches
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Chemical – herbicides to reduce or prevent
weeds
Mechanical – removal or damage to weeds
with physical/mechanical forces
Biological – suppress weeds with living
organisms including parasites or pathogens
Cultural – alter agricultural practices
(fertilize, cultivate, graze) to suppress weeds