Transcript Invasive Plants and Weedsx

INVASIVE PLANTS AND
WEEDS
Why Care?
The spread of noxious weeds:
• Signal the decline of entire ecological watersheds.
• Severely impact the biodiversity and beauty of natural
areas and cause widespread economic losses.
• Problem for urban as well as rural areas, and for private,
state, and federal lands.
• Noxious weed species spare no segment of society—
rancher, farmer, fisher, and cycler alike.
• Can’t leave well enough alone - when unmanaged, they
spread rapidly, unceasingly, and silently.
Exotic Invasive Species
– more than just plants
• plants
• animals
• microbes (fungi, bacteria, etc.)
• viruses (i.e., diseases)
Plant Terminology
• Native
• ?
• Introduced
• ?
• Invasive
• ?
• Weed
• ?
Native or Indigenous
• 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
• An organism occurring outside of its natural home range
• Other names include alien, foreign, non-indigenous
• Introduced by humans
Alien Plants –Mississippi Valley Example
http://www.youtube.com/watch?v=Brb3ES5aOcY&feature=related
Introduced, Exotic or Non-native
• Humans introduced non-native plants as:
• Grains and food crops
• Seeds in ship ballasts
• Ornamentals
• Plants for erosion control
• Plants with higher forage value
• Accidental
• Introductions of exotics continues today
Invasive Species
• 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
• Often non-native (or alien) to the ecosystem
• 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
• Abundant seed producers
• Rapid population establishment
• Long-term survival of seeds
• Occupy disturbed sites
• Competitive
• Lack of natural enemies
Cheatgrass
Juniper
Weed
• 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
• “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
• 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
• Noxious = plant species that
have been designated
“noxious” by law.
• 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.
Idaho Noxious Weed Guide:
http://digital.lib.uidaho.edu/cdm/compoundobject/collection/ui_ep/id/1294/rec/1
Plant Terminology
• Native
• Originated where they now occur without the help of
humans
• Introduced
• Introduced by humans, exotic or not native
• Invasive
• Growth characteristics that allow it to spread and
dominate the ecosystem
• Weed
• Troublesome pest that affects the health an productivity
of native landscapes
• Noxious Weeds = designated “noxious” by law
Weed Control Approaches
• Chemical
• Mechanical
• Biological
• Cultural
Weed Control Approaches
• Chemical – herbicides to reduce or prevent weeds
• Mechanical
• Biological
• Cultural
Weed Control Approaches
• Chemical – herbicides to reduce or prevent weeds
• Mechanical – removal or damage to weeds with
physical/mechanical forces
• Biological
• Cultural
Weed Control Approaches
• 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
• 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
• 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