Transcript Introduced Species

Introduced Species
HOW INTRODUCED SPECIES AFFECT
ECOSYSTEMS
Native Species
 Native species are plants and animals that naturally
inhabit an area
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Introduced Species
 Introduced species are also called foreign species or
non-invasive species
 Introduced species are plants or animals that are
brought into an ecosystem and are usually beneficial
or harmless to the ecosystem
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Invasive Species
 Some introduced species are invasive and can
destroy ecosystems
 Invasive species are organisms that can take over the
habitat of native species or invade their bodies, thus
weakening their immune systems
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Impact of Invasive Species
 Invasive species have high reproduction rate, are
aggressive competitors, and lack natural predators in
new habitats
 Such introduced species can affect native species
through:
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Competition
Predation
Disease
Parasitism, and
Habitat alteration
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Competition
 Introduced invasive species compete against native
species for essential resources such as food and
habitat
 The original community has adapted to sharing
resources, but invaders disturb this balance
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Example: Kudzu
First introduced to help control soil erosion
“The Vine that Ate the South” – runs
rampant in the Eastern US
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Predation
 Introduced predators can have more impact on a
prey population than native predators, as prey may
not have adaptations to escape or fight them
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Example: Burmese Pythons infest Everglades National Park
Have very few predators
Alligators up to five fee long have
been found inside the bellies of
captured pythons
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Disease and Parasites
 An invasion of parasites or disease-causing viruses and
bacteria can weaken the immune responses of an
ecosystem’s native plants and animals, including humans
 This weakening provides less dominant species to
outcompete other species, severely altering the ecosystem
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Example: The parasitic sea lampreys in the Great Lakes in
Eastern Canada
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Habitat Alteration
 Introduced invasive species can make a natural habitat
unsuitable for native species by changing its structure or
composition
 They may change the light levels, decrease dissolved oxygen
in water, change soil chemistry, or increase soil erosion
 They can upset the balance of nutrient cycling, pollination,
and energy flow
Example: Wild boars are one of
the world’s worse invasive species,
damaging the environment by
rooting, wallowing, and spreading
weeds that interfere with natural
succession
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