Invasive Plants and Weeds. Why Care? The spread of noxious weeds: Signal the decline of entire ecological watersheds. Severely impact the beauty and biodiversity.

Invasive Plants and Weeds

Why Care?The spread of noxious weeds: Signal the decline of entire ecological watersheds. Severely impact the beauty and biodiversity 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 on 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 Ballast 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 = 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.

Noxious Weeds

http://info.ag.uidaho.edu/pdf/BUL/BUL816.pdf

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 lay

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