Ecosystem Threats II
Ecosystems Unit, May 23rd 2007
**Major (man-made)Threats to our Ecosystems:
1.Habitat Loss
2.Chemical Pollution
3.IntroducedSpecies
4.Acid Rain
5.Climate Change
3. Introduced Species
Usually the new species has nonatural predators or diseasesto limit their populations in thisnew habitat so their populationnumbers increase rapidly!
Examples of IntroducedSpecies
1.Starlings from Eurasia to North America
2.Rabbits from England to Australia
3.Purple Loosestrife from Europe to NorthAmerica
4.Cane Toads from South America to Australia
STARLINGS
In 1890 100 starlings wereintroduced to Central Park,New York
Today there are over 200million starlings!
Starlings take over thenesting habitats of ournative birds. Their largeflocks also cause lots ofwaste, noise and eatfarmer’s grain.
Rabbits to Australia
In 1859, 24 rabbits werebrought from England toAustralia for sport hunting.
Australia had no naturalpredators that ate rabbits.
Despite lots of shooting, by1950 there were 600 millionrabbits!
Rabbits have caused theextinction of many native plantsand animals in Australia.
PURPLE LOOSESTRIFE
In early 1800s Purple loosestrifewas accidentally brought to NorthAmerica from Europe.
Seeds of the plants were in thesand that was put in the ballast ofships sailing from Europe.
This plant had no naturalpredators in North America. Eachplant could produce 3 millionseeds/yr!
Purple Loosestrife taking over a wetland
Solutions…
Never release unwantedpets into the wild!
Control the population ofinvasive species toprevent further damage.