Chapter 5 Biodiversity and Conservation

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Chapter 5 Biodiversity and Conservation

• "For if one link in nature's chain might be lost,
  another might be lost, until the whole of things
  will vanish by piecemeal."- Thomas Jefferson
• "We consider species to be like a brick in the
  foundation of a building. You can probably lose
  one or two or a dozen bricks and still have a
  standing house. But by the time you've lost 20
  per cent of species, you're going to destabilize
  the entire structure. That's the way ecosystems
  work."- Donald Falk, Christian Science Monitor,
  26 May 1989

Corbis.com
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Vanishing Species (5.1)

• Biodiversity variation in life in a given area
  or ecosystem.
• A orchard is much less diverse than a rainforest
  (fewer creatures/unit of area).
• Species of mammals Canada163, U.S. 367,
  Mexico 439.terrestrial biodiversity increases as
  you approach the equator.
• 2/3 of all land species are in the tropical
  regionswarm wet areas.
• Islands large islands have more diversity than
  small. More space for variety...frequently
  protected parks become islands in human
  habitation.

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Why is Biodiversity Important?

• Diversity is pleasing to us different lifeforms
  make the planet beautiful.
• Organisms are adapted to live in communitiesthey
  depend on one another. Losses result in losses
  in all of community (see opening quotes). Life
  depends on life.
• Biodiversity equals stability. The less variety
  is present, the more easily large portions die at
  once. Pests eat all of a cornfield, but just a
  few forest plants.
• We are part of the ecosystem. If it becomes
  brittle and endangered through loss of diversity
  (above), so do we.
• eg., air, diverse diets, CO2 removal, virtually
  all medications start as isolates from living
  thingspenicillin, quinine, aspirin, cancer drugs

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Dodo bird, Mauritius, extinct by 1681.

• Loss of Biodiversity
• Extinction loss of a species when last members
  die off forever.
• 40 known species lost in U.S. since 1980 alone.
  Passenger pigeons, woodland caribou, prairie
  voles
• Can be natural causes, of late, many due to
  humansmostly habitat destruction.
• Threatened species one whose population begins
  to decline rapidly. (African elephants,
  loggerhead sea turtles, sea otters...)
• Endangered Species one whose population is low
  enough to pose extinction threat (condors,
  manatees, black rhinos).

Passenger Pigeon, N.America, last one died in
1914 in the Cincinnati zoo.
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• In 1806 Alexander Wilson (American ornithologist)
  noted while watching a migratory flight "It was
  then half past one (when the birds first appeared
  in the sky). About four in the afternoon, the
  living torrent above my head seemed as numerous
  and extensive as ever." Wilson estimated that in
  less than 3 hours he had seen a little more than
  2 BILLION birds. In 1813 Audubon watched a
  similar 'torrent' of life that lasted for 3 DAYS.
  The last surviving bird died on September 1,1914
  at the Cincinnati Zoo, having been commercially
  hunted to extinction. (from foodreference.com)
• "Before sunset I reached Louisville, distant from
  Hardensburgh fifty-five miles, the pigeons were
  still passing in undiminished number, and
  continued to do so for three days in succession.
  The people were all in arms. The banks of the
  Ohio were crowded with men and boys, incessantly
  shooting at the pilgrims, which there flew lower
  as they passes the river. Multitudes were thus
  destroyed. For a week or more, the population fed
  on no other flesh than that of pigeons, and
  talked of nothing but pigeons." - John James
  Audubon, The Birds of America, 1844.
• Between 1866 and 1876, nearly 12 million nesting
  pigeons were killed. (from Ohio History Central)
• A monument to the passenger pigeon in a Wisconsin
  State Park declares "This species became extinct
  through the avarice and thoughtlessness of man.

Passenger pigeons laid only one egg per nesting
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• Threats to Diversity- that can result in
  extinctions, etc.
• Habitat loss. Biggest threat, esp. rainforest,
  coral reefs, and very diverse and stable
  environments.
• Habitat Fragmentation island effect. Areas cut
  off by roads and urban sprawl become virtual
  islands. Migratory species and larger animals
  (need large food gathering areas) are problem,
  cant survive in restricted areas.
• Reestablishment problem. Normally species wiped
  out of an area will replenish from elsewhere. If
  area is an island there is little opportunity
  for that.
• Edge effect inability of edges of environment
  to sustain full life means areas too small die
  out from the edges (drying forest edges example).

C D.Lambert
Moa, extinct around 1800 in New Zealand
G. Cox
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• Habitat Degradation damage to habitat due to
  pollution.
• Air, water, or land.
• Air breathing problems, irritating membranes,
  acid rain damaging soil, trees, changes lake pH.
  Burning of fossil fuels is chief cause.
• Ozone damage. O3 protects earth like sunscreen.
  Extremely vulnerable to oxidizers like
  chlorofluorocarbons (CFCs). Breakdown results in
  skin cancer and amphibian worldwide declines.
• Water industrial, animal waste, fertilizers,
  silt on coral reefs. Fertilizers often result in
  large algal blooms in water, die, decay, remove
  all oxygen. Results in loss of species and fish
  deaths. (This is common in our area).

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• Land landfills, pesticides, chemicals. DDT
  (banned in U.S.) actually relatively nontoxic to
  humans in small amounts, but does not break down
  and accumulates in tissue. Thus passed higher
  and higher up food chain, concentrated.
• Introduction of exotics new species introduced
  to environment. Can be deliberate (bringing in a
  new garden plant or bug to control a weed) or
  accidental (sea lampreys making it into Great
  Lakes via canals). Exotic species are not native
  to a particular area. They can grow
  exponentially (no competition/predators) and take
  over niches, prey on native species, destroying
  them.

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5.2 Conservation of Biodiversity

• Conservation biology new field, studies means
  of protecting biodiversity. Based on ecology
  principles.
• Resource conservation, species conservation, soil
  conservationwork with people b/c people are
  often primary cause.
• 1973, Endangered species act legally protects
  species on endangered or threatened species
  lists. Thus recoveries in Am.Bald eagles,
  alligators, brown pelican. Also international
  agreements (Convention on International Trade in
  Endangered Species CITES).
• Conservation focuses on protecting whole
  communities/ecosystemsNational Parks, whole
  community groupthus preventing many extinctions.
• Sustainable use let people use resources if not
  harmful to the environment. Local people valuing
  their forest area is very important.
• Patches of preserved area must be connects by
  natural strips that allow the migration of
  organisms from one area to another habitat
  corridors.
• Reintroduction programs-another strategy.
  Animals die out of an area permanently and are
  returned via moving them in from other native
  areas, or reintroducing them from captivity.
• Captivity a situation in which a species dies
  out in wild and exists only as preserved by human
  activity (ginkgo tree, Cal. Condors). More
  successful with plants (less expensive, animals
  can quit wild behaviors or lose their marbles in
  other ways.

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The End