Introduced Species
Introduced Species - Definition
European Rabbit in
Australia
• An organism that is not indigenous to a given location but
instead has been accidentally or deliberately introduced to a
new location by human activity or by natural means.
Problems with Introduced Species
• Introduced species sometimes are damaging to the ecosystem
they are introduced into.
Problems with Introduced Species
• Negatively affect agriculture and other human uses of natural
resources or impact on the health of animals and humans.
• Compete with native species for food and habitat.
Intentional Introductions
• Perhaps the most common motivation for introducing a
species into a new place is that of economic gain.
Example #1 Eurasian Carp
Eurasian Carp
• Introduced to U.S. as a potential food source.
Eurasian Carp cont.
Problems associated with Carp
• Uproots plants in
waterways(damaging)
• Compete with native fish and
shellfish for food.
Example #2 European Starlings
Interesting Fact:
One example of introducing an exotic animal was carried out by a
lover of the works of Shakespeare who wanted to introduce all of the
birds mentioned in Shakespeare's plays into the United States. He
deliberately released eighty starlings into Central Park in New York
City in 1890, and another forty in 1891. There are now more
European starlings in the U.S. than people.
European Starlings cont.
Problems with European starlings
• Accumulated droppings may kill trees by
their chemical concentration
• In smaller amounts, the droppings are
beneficial as a fertilizer.
Example #3 Ornamental Plants
• The transport of ornamental plants for landscaping use has
and continues to be a source of many introductions.
Ornamental Plants cont.
• Some of these species have escaped horticultural control and
become invasive.
– Examples include Norway spruce, water hyacinth, and purple
loosestrife.
Invasive Species
• Invasive species are widespread non-indigenous species.
– They don’t naturally occur in the ecosystem.
– Therefore, they may out-compete native species
• Exploit resources – HUGE FOOD SOURCE
• No natural predators
Example #1 Purple Loosestrife
Purple Loosestrife (plant)
• Arrived on ships or in the ballast water
on ships.
• The plants grow vigorously and spread
very fast.
• A single plant may produce up to three
million tiny seeds annually.
– Easily carried by wind and water, the seeds
germinate in moist soils after
overwintering.
Purple Loosestrife Strife con’t
Infestations result in:
• a dramatic disruption in water flow in rivers and canals
• a sharp decline in biological diversity as native food and
cover plant species, notably cattails, are completely crowded
out, and the life cycles of organisms from waterfowl to
amphibians to algae are affected.
Example #2 Zebra Mussel
• It is believed that zebra mussels were introduced into the great lakes in
the ballast water of ocean-going ships traversing the St. Lawrence
Seaway.
• Another possible mode of introduction is on anchors and chains,
although this has not been proven.
• Zebra mussels are very prolific animals. An adult female zebra mussel
may produce between 30,000 and 1 million eggs per year.
Zebra Mussel cont.
• Zebra mussels kill native mussels by out-competing and/or
suffocating the native species
– May cause native mussels to go extinct
• Zebra mussels also damage harbors, boats, power plants, and
water treatment plants; mostly by clogging pipes.
Example #3 Snakehead Fish
Snakehead fish
• First discovered in Crofton
MD in 2002.
• Preys on native species.
• Competes in the same
niche of native species.
Snakehead Facts
• As a family, snakeheads are
native to parts of Asia and
Africa. The Northern
Snakehead is native to China,
and possibly Korea and Russia.
• Introduced by being released
from fish Markets in Asia.
REMEMBER THIS!!!
• Introduced species may be referred to as invasive or exotic species.
• These are organisms that are not indigenous to a given location but
instead have been accidentally or deliberately introduced to a new
location by human activity or by natural means.
• Introduced species sometimes are damaging to the ecosystem they are
introduced into, others negatively affect agriculture and other human
uses of natural resources or impact on the health of animals and
humans.
Questions???
Question 1: What is an introduced species?
Question 2: What are other names used for introduced species?
Question 3: What are some common problems associated with
introduced species?
Introduced Species as Biological
Controls
Beneficial relationships
• A classical biological control is the introduction of natural
enemies (predator/prey) to a new ecosystem where they did
not originate or do not occur naturally.
• There are many examples of successful classical biological
control programs.
Example #1 Ladybugs
• Ladybugs eat aphids
(pests) on fruit plants
and ornamental
flowering plants, like
roses.
Example #2 Vedalia Beetle
(red/black)
• This beetle was introduced to control the cottony
cushion scale insect, a pest that was devastating the
California citrus industry.
• Within a few years the entire population of the
cottony cushion scale was controlled.
Questions???
Why are invasive species harmful?
What is the goal of biological pest control?
REMEMBER THIS!!!
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Introduced species may become invasive species.
May compete within the same niche as native species
May compete for same food and habitat as native species.
Introduced species may be used as biological controls to
control pests. (Usually introduced by the government)