Invasive SpeciesBy Kendall Arthur

Invasive Species “An alien species whose introduction

does or is likely to cause economic or environmental harm or harm to human health…”

“ ‘Alien species’ means, with respect to a particular ecosystem, any species that is not native to that ecosystem.”

Threats Disease Predators Competition Hybridization Habitat alteration

Example: Zebra Muscles

Disease Invasive species bring diseases not

native to the ecosystem Detrimental to native species with no

immunity Example:

Asian chestnut blight fungus 180 million acres of forest destroyed Moth species living in chestnuts became

extinct

Predators Reduce population sizes

No evolved defenses Extinction

Example: Brown Tree Snake Introduced to Guam through ship cargo Eliminated 10 of 11 species of bird species

Competition Invasive species are more efficient Native species are not as well adapted Example: North American gray squirrels

Introduced to Great Britain and Italy Driving native red squirrels to extinction Forage for nuts more efficiently

Hybridization Members of two different species mate

and successfully reproduce Invasive species is more abundant Genes “flood” the native species

Forces extinction Genotype of native species phased out

No selection for reproductive isolating mechanisms

Habitat Alteration Introduced species alter the ecological

make up Cause harm to native species Example: Zebra Mussels

Zebra Mussels Brought to U.S. (Great Lakes) from Russia

in ballast of ships Filter large amounts of water Reduce densities of planktonic organisms Settle in dense masses over expansive

areas 30 freshwater mussel species threatened

with extinction by competition

Zebra Mussels

Zebra Mussels

Zebra Mussels

Luna Pier Beach, Monroe County, Michigan

A barge in Twin Cities, Minnesota

Humans The Most Invasive

of Species

We Industrialize

Pollution Chemical pollutants

Pesticides SO2, CO, nitrogen oxides

Changes metabolism Chemical imbalances

Spread of Disease Bring diseased animals from one place

to another and infect native populations Bird flu Swine flu

Self invasive species Spread diseases across human

populations

Spread of Diseases Hawaiian Islands

Habitat fragmentation Habitat destruction Alien species Diseases

We Develop

Habitat Destruction Development of

Infrastructure Agriculture

Deforestation Waste dumping #1 cause of species extinction

Habitat Destruction In Europe, >85% natural habitat

destroyed for agriculture California coastal wetlands shrunk by

90% over 150 years 98% usable agricultural area on Earth

already developed

Deforestation 48% - Subsistence agriculture in poor

countries 32% - Commercial agriculture 14% - Commercial Logging 6% - Charcoal and other fuel wood

removal

Deforestation

Deforestation The Tropical Rainforests

Contain 50% of all 10 million species of plants, animals, and insects

50,000 disappear annually due to deforestation

“Lungs of our planet”

Deforestation The Amazon Rainforest

If destroyed, U.S. greenhouse gas emissions would increase 50 fold

90 indigenous tribes destroyed Loss of…

Medicinal knowledge of plants, trees, and other species

Great economic value if sustained

Deforestation

We Innovate

Competition The ultimate competitors Make our own resources Can outcompete any species Exploiting resources

Overexploitation Hunting

Medicine Clothing Trophies

Overfishing Shark fin soup outlawed in California

Overgrazing Agriculture

But who suffers?

Extinction Main reason

Human overpopulation of the earth Extinction rate of species accelerated

starting 1600 AD 80% of all extinctions due to habitat

destruction by humans

One last thing….

We suffer We pose a threat to future generations We have negative effect on them, but

they have no effect on us Must maintain the earth for the future We are the greatest threats to ourselves

In Conclusion… Invasive species are a danger to many

different ecosystems Humans are the most invasive species What must be done?

Maintenance Education Reforms Protection of ecosystems

Sources

Hogan, C Michael. ”Causes of Extinction." Encyclopedia of Earth. 2010. Web. 21 Nov 2011. <http://

www.eoearth.org/article/Causes_of_extinction?topic=58074>.

McGinley, Mark. "Invasive species". Encyclopedia of Earth. 2010. Web. 21 Nov 2011. http://www.eoearth.org/article

/Invasive_species?topic=49513.

Hogan, C Michael. “Deforestation.” Encyclopedia of Earth. 2010. Web. 21 Nov 2011. http://www.eoearth.org/article/Deforestation?topic=58071

"FARM: Farm Animal Rights Movement." The Cost of Disappearing Rainforests. Google Blogger, 14 Oct 2010. Web. 21 Nov. 2011.