Core Case Study: The Passenger Pigeon: Gone Forever

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Core Case Study The Passenger Pigeon Gone
Forever

• Once the most numerous bird on earth.
• In 1858, Passenger Pigeon hunting became a big
  business.
• By 1900 they became extinct from over-harvest and
  habitat loss.

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What Role Do Humans Play in the Premature
Extinction of Species?

• We are degrading and destroying biodiversity in
  many parts of the world, and these threats are
  increasing.
• Species are becoming extinct 100 to 1,000 times
  faster than they were before modern humans
  arrived on the earth (the background rate), and
  by the end of this century, the extinction rate
  is expected to be 10,000 times the background
  rate.

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Extinctions Are Natural But Sometimes They
Increase Sharply

• Local Extinction (Extirpation)
• A species is no longer found in an area it once
  inhabited but is still found elsewhere in the
  world.
• Typically the result of habitat destruction or
  overhunting and affects more than one species.
• Examples wolf and mountain lion in Maine
• Extinction (Global extinction) is Forever.

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Some Human Activities Cause Premature
Extinctions the Pace Is Speeding Up

• Estimates of current annual extinction rate
• 0.01-1.0
• 100 to 1,000 times greater than the background
  extinction rate of 0.0001
• Experts predict extinction rates will increase
  over the next 50-100 years.

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Animal Species Prematurely Extinct Due to Human
Activities

• Many animals have become prematurely extinct
  because of human activities.
• Development, habitat destructions, hunting, etc.

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Animal Species Prematurely Extinct Due to Human
Activities
The first animal species to go are the big, the
slow, the tasty, and those with valuable
parts Edward O. Wilson
(biodiversity expert)
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Endangered Natural Capital Species Threatened
with Premature Extinction

• Threatened (vulnerable) species
• Still abundant in its natural range but is likely
  to become endangered in the near future.
• Endangered species
• So few individual survivors that it could soon
  become extinct.

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Endangered Natural Capital Species Threatened
with Premature Extinction

• Extinct Ex. Dodo, Passenger Pigeon
• Extinct in the wild Ex. Alagoas Curassow
• Captive individuals survive, but there is no
  free-living, natural population
• Critically endangered Ex. Ivory-billed
  Woodpecker, Javan Rhino
• Faces an extremely high risk of extinction in
  the immediate future
• Endangered Ex. Cheetah, Blue Whale, Snow
  Leopard
• Vulnerable Ex. Lion, Wolverine
• Conservation Dependent Ex. Leopard Shark,
  Bristlecone Fir
• Would be threatened without active conservation
  programs.
• Near Threatened Ex. California Red-legged
  Frog, Silvery Woolly Monkey
• Likely to qualify as threatened soon.
• Least Concern Ex.Brown Rat, Rock Pigeon,
  Common Juniper

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Endangered Natural Capital Species Threatened
with Premature Extinction
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Endangered Natural Capital Species Threatened
with Premature Extinction
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Characteristics of Species That Are Prone to
Ecological and Biological Extinction

• Some species have characteristics that make them
  more vulnerable to ecological and biological
  extinction.
• These characteristics make survival harder when
  environmental conditions change or when humans
  interfere.

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Passenger Pigeon Hunted to extinction

• Former population about 6 billion animals

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Carolina Parakeet extinct

• Habitat loss (forest clearing), over hunted (for
  feathers and by farmers who considered them a
  pest)

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Ivory-Billed Woodpecker Critically endangered,
possibly extinct

• Once found in southern hardwood swamps and pine
  forests

• Comparison of ivory-billed (top) and pileated
  woodpecker below)

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Percentage of Various Species Threatened with
Premature Extinction
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Science Focus Estimating Extinction Rates Is
Not Easy

• Three problems with estimating extinction rate
• Hard to document due to length of time
• Only 1.8 million species identified
• Little known about nature and ecological roles of
  species identified

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Why Should We Care about Preventing Premature
Species Extinction?

• We should prevent the premature extinction of
  wild species because of the economic and
  ecological services they provide and because they
  have a right to exist regardless of their
  usefulness to us.

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Species Are a Vital Part of the Earths Natural
Capital

• Instrumental value Usefulness in terms of
  economic and ecological services
• Use value economic goods or services
• Ecotourism wildlife tourism
• Genetic information
• Potential value for medicines, foods
• and other products
• Nonuse value
• Existence value happy knowing they are around
• Aesthetic value pleasing to the eye
• Bequest value available for future generations
• Ecological value vital component of the
  ecosystem

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How do Humans Accelerate Species Extinction?

• The greatest threats to any species are
• - loss or degradation of its habitat
• - invasive species
• -human population growth
• - pollution
• - climate change
• -overexploitation.

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Loss of Habitat Is the Single Greatest Threat to
Species Remember H.I.P.P.C.O.

• H.I.P.P.C.O. the most important causes of
  premature extinction
• Habitat destruction, degradation, and
  fragmentation
• Invasive (nonnative) species
• Population and resource use growth
• Pollution
• Climate change
• Overexploitation

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Causes of Depletion and Premature Extinction of
World Species
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H.I.P.P.C.O. HABITAT LOSS, DEGRADATION, AND
FRAGMENTATION

• Habitat loss is the GREATEST threat to
  biodiversity on this planet.
• Deforestation
• Degradation of coral reefs
• Draining wetlands
• Plowing grasslands
• Habitat fragmentation when a large continuous
  habitat is divided into smaller, scattered
  patches.
• By roads, agriculture, urban developed, etc.

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H.I.P.P.C.O. HABITAT LOSS, DEGRADATION, AND
FRAGMENTATION

• Reduction in ranges of four wildlife species,
  mostly due to habitat loss and overharvest.

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H.I.P.P.C.O. HABITAT LOSS, DEGRADATION, AND
FRAGMENTATION

• Endemic Species
• Only live in one specific place (geographic
  location or habitat type usually islands)
• Very vulnerable to extinction as a result of
  habitat loss or degradation.

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• The dusky seaside sparrow is extinct. The last of
  these birds died in 1987. These sparrows lost
  their homes as marshes were destroyed.
• Since the Pilgrims landed at Plymouth Rock in
  1620, more than 500 species have become extinct
  in the U.S. alone.

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H.I.P.P.C.O. INVASIVE SPECIES

• Many nonnative species are beneficial
• Food, Medicine, Aesthetic enjoyment
• However, a few can wipe out native species,
  disrupt ecosystems, and cause large economic
  losses.
• Nonnative species can become a problem since they
  may have no natural
• Predators
• Competitors
• Pathogens/Diseases

Kudzu vine was introduced to the southeastern
U.S. in the 1930s to control erosion. Since
then, it has taken over native species habitats.
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H.I.P.P.C.O. INVASIVE SPECIES

• Many invasive species have been introduced
  intentionally

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H.I.P.P.C.O. INVASIVE SPECIES

• other invasive species have been introduced
  unintentionally.

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H.I.P.P.C.O. INVASIVE SPECIES

• The Argentina fire ant was introduced to Mobile,
  Alabama in 1932 from South America.
• Most likely from ships
• No natural predators
• Pesticide spraying in 1950s and 1960s worsened
  conditions
• Removed competition
• Lead to pesticide resistance

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Characteristics of Invader Species and Ecosystems
Vulnerable to Invading Species

• Prevention is the best way to reduce threats from
  invasive species, because once they arrive it is
  almost impossible to slow their spread.

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H.I.P.P.C.O. POPULATION GROWTH

• Humans have increased the species extinction rate
  by approximately 1,000 times.
• Experts predict that these rates will continue,
  or accelerate, in the future.

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H.I.P.P.C.O. POLLUTION

• Human activities can pollute the water, soil, or
  air on both on a local and global scale
• Water sewage, fertilizers, toxic chemicals and
  oil
• Soil pesticides, waste, herbicides and toxic
  chemicals (which may be washed from the
  land into water)
• Air smoke and gases such as CO2, CH4 or other
  gases that can lead to climate change and
  other problems

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H.I.P.P.C.O. POLLUTION

• In the 1950s and 1960s populations of fish
  eating birds plummeted to dangerously low levels
• Cause? The pesticide known as DDT
• Banned in the U.S. in 1972

• Bioaccumulation
• DDT is fat soluble and can accumulate in tissues
• Biomagnification
• the concentration of DDT in tissues increases as
  you go up the trophic levels

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H.I.P.P.C.O. CLIMATE CHANGE

• Climate change caused by global warming could
  lead to the extinction of up to 25 of all land
  plants and animals by the year 2100.
• Many (but not all) extinctions will take place in
  the upper latitudes
• Polar bears
• 17 Penguin species

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H.I.P.P.C.O. OVEREXPLOITATION

• Some protected species are killed for their
  valuable parts or are sold live to collectors.
• Killing predators and pests that bother us or
  cause economic losses threatens some species with
  premature extinction.
• Legal and illegal trade in wildlife species used
  as pets or for decorative purposes threatens some
  species with extinction.
• Bush meat indigenous people sustainably hunting
  for foodmore people more hunting

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H.I.P.P.C.O. OVEREXPLOITATION

• Poaching
• Rhinoceros are killed for their horns and sold
  illegally on the black market.
• Elephants are killed for their ivory tusks
• Tigers and other cats killed for their pelts

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How Can We Protect Wild Species from Premature
Extinction?

• use existing environmental laws and treaties and
  work to enact new laws designed to prevent
  species extinction and protect overall
  biodiversity.
• help to prevent species extinction by creating
  and maintaining wildlife refuges, gene banks,
  botanical gardens, zoos, and aquariums.
• According to the precautionary principle, we
  should take measures to prevent or reduce harm to
  the environment and to human health, even if some
  of the cause-and-effect relationships have not
  been fully established, scientifically.

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International Treaties Can Help Protect Species

• International treaties have helped reduce the
  trade of endangered and threatened species.
• One of the most powerful is
• The 1975 Convention on International Trade of
  Endangered Species (CITES)
• Lists 900 species that cannot be commercially
  traded as live specimens or wildlife products
• Signed by 172 countries
• Enforcement is difficult
• Probably only 10 of illegal trade in the U.S. is
  caught

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Case Study The U.S. Endangered Species Act

• One of the worlds most far-reaching and
  controversial environmental laws
• The 1973 U.S. Endangered Species Act (ESA)
• Overall goal is to identify and protect
  endangered species in the U.S. and abroad.
• ESA makes it illegal for Americans to engage in
  commerce associated with, or hunt / kill /
  collect, endangered or threatened species.
• ESA forbids federal agencies (besides defense
  department) to carry out / fund projects that
  would jeopardize an endangered species.

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Case Study The U.S. Endangered Species Act

• Accomplishments
• More than half of the species listed are stable
  or improving
• 99 of all listed species are still living
• Challenges
• Very small budget
• Species are listed when faced with serious threat
  of extinction
• It can take decades to bring a species
  populations up
• Suggested changes to ESA
• Increase the budget
• Develop recovery plans more quickly
• Establish a core of the endangered organisms
  survival habitat

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We Can Establish Wildlife Refuges and Other
Protected Areas

• The U.S. has set aside 544 federal refuges for
  wildlife.

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Gene Banks, Botanical Gardens, and Wildlife Farms
Can Help Protect Species

• Gene banks and botanical gardens to raise
  threatened species can help prevent extinction.
• Zoos and aquariums can help protect endangered
  animal species by preserving some individuals
  with the long-term goal of reintroduction.

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Gene Banks, Botanical Gardens, and Wildlife Farms
Can Help Protect Species

• Techniques for preserving endangered terrestrial
  animal species
• Egg pulling
• Captive breeding
• Artificial insemination
• Embryo transfer
• Use of incubators
• Cross-fostering

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The Precautionary Principle

• The Precautionary Principle
• When preliminary evidence indicates that an
  activity can harm the environment or human
  health, we should take precautionary measures to
  prevent or reduce such harm, even if we dont
  fully understand the cause/effect relationship.
• Better Safe Than Sorry
• Scientists use the precautionary principle to
  argue for the
• Preservation of species
• Preservation of ecosystems