Chapter 3.3How Introduced Species Affect

Ecosystems

Road map for today Go over and mark WB pages 46-49Warm up gameNative vs. non-native

species Invasive species and

their impacts (4) Workbook pages

52-55

What’s happening here?

Warm-up game:Name That (Invasive) Species

Warm-up game:Name That (Invasive) Species

Warm-up game:Name That (Invasive) Species

“A public health hazard, hogweed's clear, watery sap has toxins that cause photo-dermatitis. Skin contact followed by exposure to sunlight produces painful, burning blisters that may develop into purplish or blackened scars.”-Noxious weeds, King County, Washingtonhttp://www.kingcounty.gov/environment/animalsAndPlants/noxious-weeds/weed-identification/giant-hogweed.aspx

Warm-up game:Name That (Invasive) Species

Warm-up game: Name That (Invasive) Species

Videohttp://www.youtube.com/watch?v=gFchSGI0jB4

Native species vs. non-native species

• Native species are plants and animals that naturally inhabit an area

• Introduced species new species of plants and animals introduced accidentally or on purpose– A.K.A. foreign species, non-native species, exotic

species, or alien species– Many of these species are harmless, or sometimes

even beneficial– Occurred due to immigration over past 400 years

Invasive species

• Organisms that can take over the habitat of native species or invade their bodies, thus weakening immune system.

Invasive Species

• Often have high reproductive rates, are aggressive competitors, and lack natural predators in new habitats

• Have potential to dramatically change ecosystems through– Competition– Predation– Disease and parasitism– Habitat alteration

Impacts of invasive species• Competition: invasive species compete against

native species for essential resources such as food and habitat

• Predation: invasive species can have more impact on a prey population than native predators, as prey may not have adaptations to escape or fight them off

American Bullfrog

Impacts of invasive species

• Disease and Parasitism: can weaken the immune response of an ecosystem’s native plants and animals, influencing humans

• Allows opportunity for less dominant species to outcompete other species

European Starlingoutcompetes western bluebirds for nesting habitat

Norway RatEats ground-nestingsea birds’ eggs

Impact of Invasive Species

• Habitat alteration: make a natural habitat unsuitable for native species by changing its structure or composition

• E.g., scotch broom acidifies soil

• Change light level• Decrease dissolved O2

• Change soil chemistry• Increase soil erosion

West Nile Virus• Introduced to U.S. in 1999, started causing

deaths in birds and illness in humans in NY• Carried by mosquitoHow is this related to invasive species?http://www.youtube.com/watch?v=EVk5rfIA4kU

Pick two

• Silent Invaders• http://

www.youtube.com/watch?v=9JQ6oHjpeqU • Spit• http://www.youtube.com/watch?v=eqoT8tcZq6k• Death Scent• http://

www.youtube.com/watch?v=8LkRChkUIRM

Habitat alteration• Eurasian Milfoil first ID’d in

Okanagan Lake in 1970.• Forms wide, dense mats at

lake surfaces• Cuts off sunlight• Interferes with

boaters/swimmers• Can grow from fragments spreads!!!

Saving an Ecosystem Under Siege• Often requires human intervention

to save established ecosystems• Garry Oak Ecosystem Recovery

Team (GOERT) is trying to save several areas because Garry Oak trees:– Are a Keystone Species– May be better suited for future than

Douglas fir forests• Scotch broom, and English ivy are

biggest threats

Garry Oak Forests

• 95% of the original ecosystem has been lost to urban development

• The remaining 5% is threatened by invasive species.

Cleaning up the fragments of the chapter

Native speciesNon-native speciesInvasive speciesImpacts of invasive species (4) Workbook pages 52- 55 Next class…Ch3 review!Coming up… Ch 3 Celebration

of Learning!