Invasive Plants and Weeds

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 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. 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

Invasive Plants and Weeds