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Sustaining Biodiversity: The Species Approach

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Title: Sustaining Biodiversity: The Species Approach


1
Chapter 11
  • Sustaining Biodiversity The Species Approach

2
SPECIES EXTINCTION
  • Species can become extinct
  • Locally A species is no longer found in an area
    it once inhabited but is still found elsewhere in
    the world.
  • Marsh Deer, Blue Whale, Lake Sturgeon
  • Ecologically Occurs when so few members of a
    species are left they no longer play its
    ecological role.
  • Sea otter, California Spiny Lobster
  • Globally (biologically) Species is no longer
    found on the earth.

3
Global Extinction
  • Some animals have become prematurely extinct
    because of human activities.

Figure 11-2
4
Endangered and Threatened Species
  • Endangered species so few individual survivors
    that it could soon become extinct.
  • Threatened species still abundant in its natural
    range but is likely to become endangered in the
    near future.

Figure 11-3
5
Fig. 11-3, p. 224
6
SPECIES EXTINCTION
  • Some species have characteristics that make them
    vulnerable to ecological and biological
    extinction.
  • Floridas extinction

Figure 11-4
7
Estimating extinction rates
  • Scientists use measurements and models to
    estimate extinction rates.
  • The International Union for the Conservation of
    Nature and Natural Resources (IUCN) publishes an
    annual Red List, listing the worlds threatened
    species.
  • The 2004 Red List contains 15,589 species at risk
    for extinction.
  • 1 out of every 4 mammal species
  • 1 out of every 7 plant species
  • 1 out of every 8 bird speices

Figure 11-5
8
Estimating extinction rates is difficult because
  • Extinction takes a long time on a human time
    scale and documentation is limited
  • Many species are not identified
  • We know little about the species we have
    identified

9
SPECIES EXTINCTION
  • Percentage of various species types threatened
    with premature extinction from human activities.

Figure 11-5
10
IMPORTANCE OF WILD SPECIES
  • Ecological services
  • Control pests, store carbon, recycle nutrients
  • Economic services
  • Food, fuel, timber, paper, medicines
  • Genetic information
  • Recreational pleasure
  • Ecotourism
  • Biophilia affinity for nature

11
HABITAT LOSS, DEGRADATION, AND FRAGMENTATION
  • Conservation biologists summarize the most
    important causes of premature extinction as
    HIPPO
  • Habitat destruction, degradation, and
    fragmentation
  • Invasive species
  • Population growth
  • Pollution
  • Overharvest

12
HABITAT LOSS, DEGRADATION, AND FRAGMENTATION
  • The greatest threat to a species is the loss,
    degradation, and fragmentation of where it lives.

Figure 11-7
13
HABITAT LOSS, DEGRADATION, AND FRAGMENTATION
  • Reduction in ranges of four wildlife species,
    mostly due to habitat loss and overharvest.

Figure 11-8
14
Which species are most vulnerable?
  • Specialist
  • K strategist- low reproductive rate
  • Contain desirable characteristics
  • video

15
Case Study A Disturbing Message from the Birds
  • Human activities are causing serious declines in
    the populations of many bird species due to
    deforestation, introduction of nonnative species,
    nets in oceans, power lines, and buildings.

Figure 11-9
16
INVASIVE SPECIES
  • Many nonnative species provide us with food,
    medicine, and other benefits (like reduced soil
    erosionkudzu) but a a few can wipe out native
    species, disrupt ecosystems, and cause large
    economic losses.

Kudzu vine was introduced in the southeastern
U.S. to control erosion. It has taken over native
species habitats.
Figure 11-A
17
INVASIVE SPECIES
  • Many invasive species have been introduced
    intentionally.

Figure 11-11
18
INVASIVE SPECIES
  • Many invasive species have been introduced
    unintentionally.

Figure 11-11
19
INVASIVE SPECIES
  • The Argentina fire ant was introduced to Mobile,
    Alabama in 1932 from South America.
  • Most probably from ships.
  • No natural predators.
  • Zebra Mussels in the Great Lakes

Figure 11-12
20
INVASIVE SPECIES
  • Prevention is the best way to reduce threats from
    invasive species, because once they arrive it is
    almost impossible to slow their spread.

Figure 11-13
21
Characteristics of Successful Invader Species
Characteristics of Ecosystems Vulnerable to
Invader Species
Climate similar to habitat of invader
Absence of predators on invading species Early
successional systems Low diversity of
native species Absence of fire Disturbed by
human activities
High reproductive rate, short generation
time (r-selected species) Pioneer species
Long lived High dispersal rate Release
growth-inhibiting chemicals into soil
Generalists High genetic variability
Fig. 11-13, p. 236
22
POPULATION GROWTH, POLLUTION, AND CLIMATE CHANGE
  • Population growth, affluenza, and pollution have
    promoted the premature extinction of some
    species.
  • Projected climate change threatens a number of
    species with premature extinction.
  • Polar bears

23
Pollution
  • Each year pesticides
  • Kill about 1/5th of the U.S. honeybee colonies.
  • 67 million birds.
  • 6 -14 million fish.
  • Threaten 1/5th of the U.S.s endangered and
    threatened species.

Example of biomagnification of DDT in an aquatic
food chain.
Figure 11-15
24
OVEREXPLOITATION
  • Some protected species are killed for their
    valuable parts or are sold live to collectors.
  • Legal and illegal trade in wildlife species used
    as pets or for decorative purposes threatens some
    species with extinction.
  • Burmese python

25
OVEREXPLOITATION
  • Rhinoceros are often killed for their horns and
    sold illegally on the black market for decorative
    and medicinal purposes.

Figure 11-16
26
Case Study Rising Demand for Bushmeat in Africa
  • Bushmeat hunting has caused the local extinction
    of many animals in West Africa.
  • Can spread disease such as HIV/AIDS and ebola
    virus.

Figure 11-17
27
PROTECTING WILD SPECIES
  • International treaties have helped reduce the
    international trade of endangered and threatened
    species, but enforcement is difficult.
  • One of the most powerful is the 1975 Convention
    on International Trade of Endangered Species
    (CITES).
  • Signed by 169 countries, lists 900 species that
    cannot be commercially traded.

28
The U.S. Endangered Species Act
  • One of the worlds most far-reaching and
    controversial environmental laws is the 1973 U.S.
    Endangered Species Act (ESA).
  • ESA forbids federal agencies (besides defense
    department) to carry out / fund projects that
    would jeopardize an endangered species.
  • ESA makes it illegal for Americans to engage in
    commerce associated with or hunt / kill / collect
    endangered or threatened species.

29
Other acts/treaties to protect species
  • National Marine Fisheries Service- id and protect
    threatened or endangered marine species
  • US Fish and Wildlife Service- id and protect
    threatened or endangered terrestrial species

30
PROTECTING WILD SPECIES
  • Gene banks, botanical gardens and using farms to
    raise threatened species can help prevent
    extinction, but these options lack funding and
    storage space.
  • Zoos and aquariums can help protect endangered
    animal species by preserving some individuals
    with the long-term goal of reintroduction, but
    suffer from lack of space and money.

31
RECONCILIATION ECOLOGY
  • Reconciliation ecology involves finding ways to
    share places we dominate with other species.
  • Replacing monoculture grasses with native
    species.
  • Maintaining habitats for insect eating bats can
    keep down unwanted insects.
  • Reduction and elimination of pesticides to
    protect non-target organisms (such as vital
    insect pollinators).

32
What Can You Do?
Protecting Species
Do not buy furs, ivory products, and other
materials made from endangered or threatened
animal species. Do not buy wood and paper
products produced by cutting remaining
old-growth forests in the tropics. Do not buy
birds, snakes, turtles, tropical fish, and other
animals that are taken from the wild. Do not
buy orchids, cacti, and other plants that are
taken from the wild. Spread the word. Talk to
your friends and relatives about this problem and
what they can do about it.
Fig. 11-21, p. 246
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