Transcript NON-NATIVE SPECIES

NON-NATIVE SPECIES
A MODERN-DAY CAUSE OF
COMPETITION AND
EXTINCTION
What Are Native Species?
• Native species are those that normally live
and thrive in a particular community. They
occupy specific habitats and have specific
niches in their native environment. They
have natural predators that help to keep
their populations in check.
What Are Non-Native Species?
• Species that
migrate into an
ecosystem or are
deliberately or
accidentally
introduced into an
ecosystem by
humans.
Africanized Honeybee (Killer Bees)
• 1957 African honey be crossed with native
honey bee to produce an overly aggressive
bee in Brazil which escaped.
• Displaced the native honeybee through
competitive exclusion and migrated
northward at a rate of 200 miles per year.
• Northward migratory rate slowing down
due to climate (frost).
• Will global warming allow their migration to
move northward over time?
• Problems: They are so aggressive, they
not only out-compete native bee
populations, but pose great health threats
to humans.
Geographic Distribution of
Africanized Honey Bees in USA
Fire Ants
• Late 1930’s introduced by accident in Alabama
in shiploads of lumber and cargo.
• Interspecific competition reduced native ant
species by 90%!
• Fire ants are very aggressive and through direct
combat reduced native species.
• Since there are no natural predators, they
produced more colonies than native ants and
increased their population density significantly in
south.
Fire Ants
• Interference Competition – fire ants consumed
food and invaded habitat of native ant species
(competitive exclusion principle).
• They release sulfuric acid when they bite and
can kill deer fawn, lizards, birds, livestock, pets,
and human babies.
• Fire ants have invaded trucks and caused
roadside accidents when drivers have been
attacked.
• Chew through underground cables and disrupt
electric and phone service and have started
electrical fires in the south.
Fire Ants
• They are pesticide resistant
(Directional Natural Selection
of r-strategists)
• USDA (US Department of
Agriculture) has introduced a
non-native parasitic fly that
deposits eggs on the fire
ants. When the larvae
develop, they eat the heads
of the fire ant. CHAOS!
$$$$$$$$
Fire Ant Distribution in the USA
(Degrees Celsius)
Kudzu Vine
• 1930’s - imported from Japan and planted in the
southeastern USA to help combat soil erosion following
the Dust Bowl.
• 1940’s – US Soil Conservation Service (federal agency)
paid farmers a subsidy to grow kudzu vine.
• Problems: No natural predators, very prolific
reproduction. Costs USA government $500 million/year
to eradicate!
• Possible Commercial Uses: Chemicals produced in the
vine are used in Japan to combat diseases.
• USA found chemicals in vine may reduce alcoholic
cravings.
• May be a source for paper products!
Kudzu Vine Distribution in USA
Bamboo
Wooly Adelgid
Wooly Adelgid
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Native to East Asia
First found in VA in 1950’s
Decimating Hemlock population
No natural predators
Hemlock has no defense against
What Are Indicator Species?
• Indicator species serve as early warnings of
damage to a community.
• Birds and butterflies are migratory and are
excellent indicators of the environment. They do
not return to areas along their migratory routes
where deforestation has occurred or where
broad spectrum pesticides have been applied.
• Amphibians are also a universal indicator of
environmental degradation as they respire
through their skin.
Why Are Amphibians Vanishing?
• Appeared in the fossil record about 350
million years ago.
• Frogs and toads have been around for 150
million years (indicates adaptability)
• Last 20 years nearly 3,000 species of
frogs and toads have disappeared.
Reasons for Global Amphibian
Declines
• Global climate change (Costa Rican golden toads)
• Dehydration weakens amphibians, susceptible to fatal
diseases.
• Introduction of non-native predatory fish into aquatic
habitats.
• Pollution (air, water, soil)– respire through skin.
• Consume insects that take up pesticides
(bioacumulation/biomagnification).
• Eggs sensitive to increases in UV radiation – endocrine
blockers)
• Consumption of frog legs (delicacy).
• Loss of habitat.
Indicator Species
• As indicator species,
amphibians may be
sending us an
important message
about the health of
the global
environment.
• They don’t need us,
but we and other
species need them.
Golden toads – once prevalent in
Costa Rica’s cloud forest have
disappeared.
Indicator Species on Long Island
Why Should We Care About
Indicator Species?
• They give clues that the environmental health is
deteriorating in parts of the world such as habitat
loss and degradation, pollution, UV exposure,
and climate change.
• They provide ecological services (niche) in
biological communities. ie. Amphibians eat more
insects including mosquitoes than birds. They
provide a food source for higher trophic levels.
• Amphibians especially provide a storehouse of
pharmaceutical products waiting to be discivered
(economic goods and services).
What Are Keystone Species?
• A keystone species holds a community
together, when it disappears, so does the
biological community. Elimination of a
keystone species dramatically alters the
structure and function of a community.
American Alligator – a Keystone
Species
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Largest North
American reptile;
only humans are
their predator.
Hunted nearly to
extinction for
exotic meat, and
leather to make
shoes and
pocketbooks,
and for sport.
Ecological Niche of American
Alligator
• Dig gator holes that collect freshwater
during the dry season which serve as
refuges for aquatic life, and supply
freshwater and food for many animals.
Ecological Niche of American
Alligator
• Alligator nesting mounds serve as nesting
and feeding sites for herons and egrets
Ecological Niche of American
Alligator
• Alligator eat large numbers of predatory
gar fish and help maintain healthy
numbers of game fish such as bass and
bream.
Ecological Niche of American
Alligator
• As alligators
move from gator
holes to nesting
sites, they keep
areas of open
water free of
invading
vegetation. This
helps to maintain
healthy
ecosystems with
flowing water.
American Alligator Protection
• In 1967, the US
Government placed
the American
alligator on the
Endangered Species
List, which protected
it from hunting.
• By 1975, the
American alligator
populations
rebounded
successfully.
Status of the American Alligator.
• In 1977, the US Fish and Wildlife Service
(DOI), down-listed the American alligator
to a threatened species in Florida,
Louisiana, and Texas.
• Limited kills with a license are permitted.
Recreational lotteries are held in the
Florida Everglades each year by FWS.
• Alligator farms established to fulfill the
market for alligator goods.
Why Should We Protect keystone
Species?
• They play critical roles in the cross pollination of
angiosperms (bees, hummingbirds, bats).
• Top predator keystone species help regulate the
population numbers of other species.
• The loss of keystone species can lead to
population crashes and extinctions of other
species that depend on it for ecological services.
E.O. Wilson
• “The loss of a keystone species is like a
drill accidentally striking a power line. It
causes lights to go out all over”
The Good News Is…
• Conservation Efforts on the
rise –
• President Theodore
Roosevelt (1901-1909) “the
Golden Age of
Conservation”
• 1903 he established the first
federal refuge at Pelican
Island off the east coast of
Florida to protect the
endangered brown pelican.
What Is Our Future?
• “ By reducing and degrading life’s support
systems (Earth Capital), we could make
our own species more vulnerable to
extinction, or at least to a massive
population crash”.
• If we are the most “intelligent” species on
Earth, why can’t we follow the simple laws
of nature?
What Can You Do?
• Education
• Participate in local groups to conserve the
biological integrity of ecosystems
• Promote local economic growth while
thinking globally
• Refuse, Reduce, Reuse, Recycle
• Shop locally, think globally (be an
educated consumer)
• GET INVOLVED AND TELL A FRIEND