2. Invasive species and
Overexplotation
Exotic: Organisms that have been introduced
by human activity into an ecosystem where
they are not native.
Invasive
species:
Exotic that spreads
naturally into natural or semi-natural habitat,
they increase in abundance at the expense of
native species.
Introduction of Invasive species?
1.Accidental introduction.
2.Purposeful introduction
and
accidental 2

3. Harmful Impacts
1.
2.
3.
4.
Out-compete native species.
Cause disease in native species.
Prey on native species to point of extinction.
Degrade habitats so that native are no longer
to persist.
Invasive species of Pakistan
•
•
•
•
Eucalyptus plant was imported
Australia.
Consume more water (disturbed
water table).
It harm plants growth near by.
from
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4. Paper Mulberry in Islamabad
• Native to eastern Asia.
• Introduced for its scenic value, but is now
replacing the native flora at an alarming rate.
• High consumption of water, which leaves less
water to sustain the native flora.
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5. Purple loosestrife
• Introduced from Europe and dominated many
North America wet land.
• So aggressive that it chokes out native
plants, destroying wildlife habitat
1968
1978
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6. Zebra mussels
• First introduced in the Great Lakes by ballast
water.
• Multi-billion dollar threat.
• They out-compete native mussels.
• Within two year of introduction ,
they reached densities of 700,000.
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7. Comb jelly
• 1982
Black Sea introduction is
accidentally by ballast water.
• It caused a dramatic drop in fish
populations by competing for the same
food sources .
• Biological control was
tried with Beroe ovata,
another comb jelly,
with some degree of success
has been achieved.
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8. lamprey
• Primitive jawless fish—has a sucker mouth
• Parasite that attaches to large fish
• Came into the Great Lakes from the Atlantic
Ocean
• Only about 1 in 7 fish survive attack by
lamprey
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9. Fire Ants
• In southern United State, diversity of insect
species decline 40% after the invasion of
exotic fire ants
• abundance of northern bobwhite in Texas has
decline over a 20 year period(effect at nestling
stage)
• Nuisance to people.
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10. Brown Tree snake
• Introduced onto number of Pacific islands
• It devastate endemic bird population by
eating eggs, nestling and adult birds.
• Invasive species has driven 8 of 11 forest
species extinct.
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11. OVER EXPLOTATION
Def: Overexploitation is the use, by the
human, of a natural resources to an extant,
that is not sustainable.
• Also called as overharvesting.
Causes of Overexploitation
1.Possibly rich countries over consume.
2.Increase in human population number.
3.Lack of incentive to conserve biodiversity.
4.Results from large ,poor ,rural population
and
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12. extensive use of wildlife for both food and
traditional medicines
5. Improve methods of harvesting leading to the
empty habitat.
EXAMPLES:
Commercial exploitation of whale
• Whales are slaughtered for spermaceti oil (oil
form sperm whale) meat, baleen(whale bone)
leads to the decrease in the population of the
whale.
• International whaling
commission IWC regulates
whale hunting.
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13. International trade in fur
Mamo Bird
• A single ceremonial cloaks worn
by Hawaiian king were made
from feathers of Mamo birds.
• A single cloak use the feathers
of 70,000 birds of this now
extinct species.
Carolina parakeet
• The only parrot species native to
the eastern United States, was
hunted for crop protection and
its feathers.
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14. The Great Auk
• The bird had few natural predators, it has no fear
of human which made them easier to hunt.
• It was found in Canada, Greenland, Iceland,
Norway and great Britain.
• Being flightless it was a
hunters dream.
• The bird was used for
• food and feathers.
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15. Bluefin tuna
• The northern bluefin tuna is currently seriously
overexploited.
• Scientists say 7,500 tons annually is the
sustainable limit, yet the fishing industry
continues to harvest 60,000 tons.
• Commercial fishing demonstrates that industry
working one species after
another to the point of
diminishing returns a process
some time terms fishing down
the food chain.
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16. The Amphibian and Reptile Industry
,Food:
• Certain frog species are particularly
persecuted along with a few lizards, turtles,
crocodiles and alligators.
• The USA import 2.5 million kilogram frog legs
from Japan and India.
• Brightly colored frogs, such as the Poison or
dart frogs are also threatened by
overexploitation for sale in the pet trade.
• Because of bright colored they are highly
valued by hobbyists.
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17. • CORAL REEF
• The rich diversity of marine life inhabiting
coral reefs attracts bioprospectors. Many
coral reefs are overexploited.
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18. • Other species affected by overexploitation
include:
• The international trade in fur: chinchilla,
and numerous cat species.
• Insect collectors: butterflies
• Shell collectors: Marine molluscs
• Aquarium hobbyists: tropical fish
• Chinese medicine: bears, tigers
• Novelty pets: snakes, parrots and
primates
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19. • RHINOCEROS become rare due to
overexploitation the price of its horns rises
making its more value able on black
market .
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20. • CONTROL OF OVER EXPLOITATION:
• 1. RIGHTS TO SPECIFIC HARVESTING
TERRITORY were rigidly controlled.
• 2. Hunting and harvesting in certain areas
must be banned.
• 3. Prohibition against harvesting female
juvenile and undersized animals
• 4. Efficient methods of harvesting is not
allowed
• 5. Certain season of years and time of the
days were close for the harvesting.
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