Transcript Introduced Species

Ecosystem Threats II
Ecosystems Unit, May 23rd 2007
**Major (man-made)
Threats to our Ecosystems:
1.
2.
Habitat Loss
Chemical Pollution
3.
Introduced
Species
4.
Acid Rain
Climate Change
5.
3. Introduced Species

Humans have both
intentionally and
unintentionally brought new
plants and animals to new
habitats.

Usually the new species has no
natural predators or diseases
to limit their populations in this
new habitat so their population
numbers increase rapidly!
Examples of Introduced
Species
1.
2.
3.
4.
Starlings from Eurasia to North America
Rabbits from England to Australia
Purple Loosestrife from Europe to North
America
Cane Toads from South America to Australia
STARLINGS

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In 1890 100 starlings were
introduced to Central Park,
New York
Today there are over 200
million starlings!
Starlings take over the
nesting habitats of our
native birds. Their large
flocks also cause lots of
waste, noise and eat
farmer’s grain.
Rabbits to Australia


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In 1859, 24 rabbits were
brought from England to
Australia for sport hunting.
Australia had no natural
predators that ate rabbits.
Despite lots of shooting, by
1950 there were 600 million
rabbits!
Rabbits have caused the
extinction of many native plants
and animals in Australia.
Invasive Rabbits in Australia Video Clip
PURPLE LOOSESTRIFE


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In early 1800s Purple loosestrife
was accidentally brought to North
America from Europe.
Seeds of the plants were in the
sand that was put in the ballast of
ships sailing from Europe.
This plant had no natural
predators in North America. Each
plant could produce 3 million
seeds/yr!
Purple Loosestrife taking over a wetland
Leaf Eating Beetles
Effects of
Beetles on
Purple
Loosestrife
in a wetland
in Ontario
Video of Water
Hyacinth
Cane Toads

http://www3.nationalgeographic.com/a
nimals/video/toad_cane.html
Solutions…

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Never release unwanted
pets into the wild!
If possible, eliminate the
new species from the
introduced habitat.
Control the population of
invasive species to
prevent further damage.