Chapter 12 Biodiversity: The Species Approach

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Chapter 12 Biodiversity The Species Approach
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What are the three types of species extinction?

• The three levels of species extinction are local,
  ecological, and biological.
• Local extinction occurs when a species disappears
  from an area in which it once inhabited, but is
  found elsewhere in the world.
• Ecological extinction occurs when the number of
  members of a particular species is so low that
  they cannot fulfill their ecological roles in
  their biological communities.
• Biological extinction occurs when a species has
  disappeared from the earth.

How do we classify Organisms headed for
extinction?
Endangered species are so few in number that the
species could soon become extinct over all or
part of its natural range. Threatened/vulnerable
species are still abundant in their natural range
but, because of loss in numbers, is likely to
become endangered in the near future. (E.O.
Wilson states) The first species to go tend to
be the big, slow, and tasty and whose valuable
parts can be sold. The passenger pigeon
represents lost natural capital, primarily
because of overhunting and habitat destruction
directly attributable to man. A survey in 2000
(Natural Conservancy) found that about one-third
of 21,000 animal and plant species in the U.S.
are vulnerable to premature extinction.
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Determining Extinction

• Estimates of the current rate of species
  extinction are based on information about habitat
  destruction and species-area relationship, use of
  models such as
• (1) population viability analysis (PVA),
  estimates of (2) minimum viable population
  (MVP), estimates of (3) minimum dynamic area
  (MDA), and differing assumptions about the
  earth's total number of species, their
  distribution, and the rates of tropical
  deforestation.

Characteristics of species that are prone to
extinction

• Low reproductive rate (K-strategist)- Blue whale,
  giant panda, rhinoceros
• Specialized niche Blue whale, giant panda,
  Everglades kite
• Narrow distribution many island species,
  elephant seal, desert pupfish
• Feeds at a high trophic level- Bengal tiger, bald
  eagle, grizzly bear
• Fixed migratory patterns- Blue whales, whooping
  cranes, sea turtles
• Rare- Many island species, African violet, some
  orchids
• Commercially valuable- Snow leopard, tiger,
  elephant, rhinoceros, rare plants and birds
• Large territories- California condors, grizzly
  bears, Florida panthers

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What is the impact of human activities on
extinction?

• Currently, the rate of extinction is estimated to
  be 1,00010,000 times the rate before mankind
  existed.
• Using estimated extinction rates, 20 of the
  worlds present plant and animal species will be
  gone by 2030 50 would vanish by 2099.

Factors influencing greater extinction rates

• Species loss and biodiversity loss will likely
  increase because of exponential population
  growth.
• Biologically diverse areas (hot spots) rate of
  extinction may be as high as 2550. The
  extinction rate in these hot spots deserves
  special attention.
• Possible colonization sites for new species are
  being eliminated, degraded, and simplified by
  human activities so that new species cannot
  arise. By reducing this rate of speciation, we
  are creating a speciation crisis.
• Solution? - A precautionary strategy to prevent
  a significant decrease in the genetic, species,
  ecological, and functional diversity of the earth
  is necessary.

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Why should we preserve wild species?

• Wild species have valueeconomic and
  ecologicalwhich are important to the earth.
• We are destroying species biodiversity more
  quickly than new species can evolve. It will take
  5 million years for speciation to rebuild the
  animals and plants we will destroy in 100 years.
  We should preserve species for their instrumental
  value.
• Instrumental value- usefulness of a species to us
  in the form of economic or ecological services

Examples Mountain Gorillas Thailand Species
Trade Sharks
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What are some of the economic and ecological
benefits?

• Medicinal properties are found in many plants and
  some animals.
• Genetic information in species helps them adapt
  and produce new species. This information can be
  used to develop food and medicines for people.
  Wild species provide a bank of genetic
  information.
• Recreational value is provided by plants and
  animals.
• Eco-tourism generates money to help poor
  countries preserving plants and animals is much
  more economically wise than destroying them.
• A male lion skin is worth 1,000 a male lion
  living for 7 years produces 515,000 in tourist
  dollars.
• Bats, often targeted for destruction by man, feed
  on crop-damaging insects, pollinate flowers, as
  well as distribute plants by excreting undigested
  seeds. Bats are keystone species in the tropics.
• Some of the economic and ecological benefits of
  present species have not even been identified we
  are destroying our chance for a a future.

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Secondary factors leading to premature
extinction HIPPO Habitat destructions and
fragmentation, Invasive (alien) species,
Population growth, Pollution and Overharvesting
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Habitat destruction and fragmentation Species are
more vulnerable to extinction when their habitats
are divided and in to smaller more isolated
patches
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Invasive Species

• Deliberate or accidental introduction of
  nonnative species can trigger ecological
  disruptions that lead to premature extinction of
  native species. Once a nonnative species gets
  established in an ecosystem, its wholesale
  removal is virtually impossible. The best
  strategy is to prevent nonnative species from
  being introduced and becoming established.

Solution Prevention is the best way to reduce
the threats from nonnative species because once
they have arrived it is difficult and expensive
to slow their spread.
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Invasive Species
Kudzu
Figure 12-10 Kudzu taking over a house and a
truck. This vine can grow 5 centimeters (2
inches) per hour and is now found from east Texas
to Florida and as far north as southeastern
Pennsylvania and Illinois. Kudzu was deliberately
introduced into the United States for erosion
control, but it cannot be stopped by being dug up
or burned. Grazing by goats and repeated doses of
herbicides can destroy it, but goats and
herbicides also destroy other plants, and
herbicides can contaminate water supplies.
Recently, scientists have found a common fungus
(Myrotheciurn verrucaria) that can kill kudzu
within a few hours, apparently without harming
other plants.
Fire Ants
Figure 12-11 Natural capital degradation expansio
n of the Argentina fire ant in southern
states, 1918-2000. This invader is also found in
Puerto Rico, New Mexico, and California, (Data
from U.S. Department of Agriculture)
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Impact of Population Growth

• Deer populations have exploded in the suburbs due
  to invasion of their habitats by humans.
• Deer are edge species they live in the woods and
  feed in more open areas.
• Deer kill more people in the U.S. than any other
  wild species due to collisions between deer and
  vehicles.
• No easy answers are available for reducing the
  deer population each proposed remedy is
  generally expensive and time consuming.
• Researchers are experimenting with various
  possible methods of birth control to decrease the
  population.

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Poaching and Hunting

• At least one-fourth of the international trade in
  wild plants and animals involves the illegal sale
  of endangered or threatened species or their
  parts. Most demand for illegal wildlife comes
  from wealthy consumers, but illegal hunting for
  bushmeat as a source of protein for local people
  and for restaurants in many parts of the world is
  a growing problem.

Page 239 Planet in Peril Video Clip To poachers,
a live mountain gorilla is worth 150,000, a
panda pelt 100,000 (only about 1,500 pandas are
left in the wild), a chimpanzee 50,000, and an
Imperial Amazon macaw 30,000. A rhinoceros horn
is worth as much as 28,600 per kilogram (13,000
per pound) because of its use in dagger handles
in the Middle East and as a fever reducer and
alleged aphrodisiac in Chinathe world's largest
consumer of wildlifeand other parts of Asia.
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Protecting Wild Species- Legal Approach

• The 1975 Convention on International Trade in
  Endangered Species (CITES) has helped to reduce
  international trade in many threatened animals.
  The Convention on Biological Diversity (CBD)
  binds signatory governments to reversing the
  decline in biodiversity, but it has not been
  ratified by the United States and some other key
  governments.
• In the United States, The Lacey Act of 1900
  prohibits the transport of live or dead animals
  or their parts across state lines without a
  permit. The Endangered Species Act of 1973 (ESA)
  prohibits the import or trading of products made
  from an endangered or threatened species.

ESA Controversy
There is controversy over whether the government
should compensate private property owners who
suffer financial losses when it restricts how
they can use their land because of the presence
of threatened or endangered species. Congress
has amended the Endangered Species Act to help
landowners protect endangered species on their
land. Safe-harbor agreements and voluntary
candidate conservation agreements
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U.S. Biological hot spots and recovery plans
Examples of successful recovery plans include
those for the American alligator, the gray wolf,
the bald eagle, and the peregrine falcon. Bad
news. About half of current recovery plans exist
only on paper, mostly because of political
opposition and limited funds.
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Protecting Wild Species The Sanctuary Approach

• The sanctuary approach is being used to protect
  wild species.
• 542 federal refuges protect wildlife, but the
  habitats are deteriorating due to invasive
  species, pollutants, and little operational or
  maintenance funding.
• About one-fifth of U.S. endangered and threatened
  species have habitats in the refuge system.
• Human overuse by hunters, fishermen, and off-road
  vehicle traffic has hurt the refuges.
• Gene banks, botanical gardens, and farms can be
  used to raise threatened species and help protect
  species from extinction, but funding is
  inadequate.
• Raising some threatened or endangered species on
  farms can take some of the pressure off them and
  perhaps offer some for commercial sale.
• Zoos and aquariums can help protect some
  endangered animal species as well, but they are
  both notoriously underfunded.
• More than three-fourths of the refuges are
  concentrated along major bird migration
  corridors.

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Major Migratory Flyways
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Reconciliation Ecology

• Reconciliation Ecology the science of
  inventing, establishing and maintaining new
  habitats to conserve species diversity in place
  where people live, work or play.
• Michael L. Rosenzweig (Win-Win Ecology How
  Earths Species Can Survive in the Midst of Human
  Enterprise) identifies the real challenge for
  biodiversity to sustain wild species in the
  human-dominated portion of nature.
• Rosenzweig advocates that we implement
  reconciliation ecology learn to share the spaces
  we dominate with other species. It is the science
  of inventing, establishing, and maintaining new
  habitats to conserve species diversity where
  people live out their lives.

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Reconciliation Ecology

• There are several ways to implement
  reconciliation ecology.
• Maintain diverse yards using native plants, which
  attract certain species.
• Share responsibility for supporting bio-diverse
  yards and gardens.
• Apply reconciliation ecology to local plant and
  animal life (for example, bluebirds project).
• Planting rooftop gardens can support a variety of
  species, provide insulation, reduce
  evapotranspiration, conserve water, and cool
  cities.
• Golden Gate Park in San Francisco is a good
  example of reconciliation ecology it was
  transformed from sand dunes to park by humans.
• Government land, college campuses, and schools
  could be used for reconciliation ecology
  laboratories.

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