Plant and Animal Immigrants
Nature Bulletin No. 43 December 1, 1945
Forest Preserve District of Cook County
Clayton F. Smith, President
Roberts Mann, Superintendent of Conservation
PLANT AND ANIMAL IMMIGRANTS
When foreign plants and animals are brought to a new country they
either become naturalized and thrive, or they cling to their old ways and
die out. after they, too, find new freedoms because they leave their
enemies, competitors, parasites, and some of their diseases behind them
-- much as immigrant people do.
The United States now supports about 300 times as many people as it
did when Columbus discovered America. This is possible because the
domesticated plants and animals that the early settlers brought with
them give much higher yields of food and clothing than the Indians got
from wild ones.
now some of these domestic animals and plants go wild. Honey
bees leave their hives and do very well in hollow trees. The banks of
many ponds created to hold and breed German carp broke in the 1880's
and in a few years carp were the most common fish in the lakes and stre
aras of such states as Illinois. Pigeons, starlings and sparrows in
Chicago -- and in many other cities -- have become a nuisance.
Abandoned dogs and cats have learned to hunt for themselves and rear
their young in the forest preserves. The ringneck pheasant has increased
in such numbers that in some states they are crop pests in spite of the
fact that millions are killed annually by hunters.
Carelessly, man has also brought here many household pests -- such as
mice, rats, sparrows, starlings, cockroaches and bedbugs; as well as
crop pests such as the Hessian fly, the European cornborer, the
Japanese beetle; and weeds like the European bindweed, the Russian
thistle, the Canadian thistle.
Other stowaways -- including the nightcrawler and several other species
of earthworms -- are actually beneficial.
They may be foreign in origin, and cause lots of disturbance and
trouble, but after a long enough time they change their ways and find
their place and become Americans just like the rest of us.
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Update: June 2012