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Sustaining Biodiversity: The Species Approach

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Chapter 12 Sustaining Biodiversity: The Species Approach * * Figure 11.8 Natural capital degradation: reductions in the ranges of four wildlife species, mostly as the ... – PowerPoint PPT presentation

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Title: Sustaining Biodiversity: The Species Approach


1
Chapter 12
  • Sustaining Biodiversity The Species Approach

2
Chapter Overview Questions
  • How do biologists estimate extinction rates, and
    how do human activities affect these rates?
  • Why should we care about protecting wild species?
  • Which human activities endanger wildlife?
  • How can we help prevent premature extinction of
    species?
  • What is reconciliation ecology, and how can it
    help prevent premature extinction of species?

3
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.

Figure 12-1
4
Animation Humans Affect Biodiversity
PLAY ANIMATION
5
SPECIES EXTINCTION
OBJ 12.1
  • 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.
  • Ecologically Occurs when so few members of a
    species are left they no longer play its
    ecological role.
  • Globally (biologically) Species is no longer
    found on the earth.

6
Global Extinction
  • Some animals have become prematurely extinct
    because of human activities.

Figure 12-2
7
Endangered and Threatened Species Ecological
Smoke Alarms
OBJ 12.2
  • 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 12-3
8
FLORIDAS ENDANGERED SPECIES
OBJ 12.4
9
SPECIES EXTINCTION
OBJ 12.3
  • Some species have characteristics that make them
    vulnerable to ecological and biological
    extinction.

Figure 12-4
10
SPECIES EXTINCTION
  • 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.

Figure 11-5
11
SPECIES EXTINCTION
  • Percentage of various species types threatened
    with premature extinction from human activities.

Figure 12-5
12
SPECIES EXTINCTION
  • Scientists use models to estimate the risk of
    particular species becoming extinct or endangered.

13
IMPORTANCE OF WILD SPECIES
  • We should not cause the premature extinction of
    species because of the economic and ecological
    services they provide.
  • Some believe that each wild species has an
    inherent right to exist.
  • Some people distinguish between the survival
    rights among various types of species (plants vs.
    animals).

14
HABITAT LOSS, DEGRADATION, AND FRAGMENTATION
OBJ 12.5
  • Conservation biologists summarize the most
    important causes of premature extinction as
    HIPPO
  • Habitat destruction, degradation, and
    fragmentation
  • Invasive species
  • Population growth
  • Pollution
  • Overharvest

15
Animation Habitat Loss and Fragmentation
PLAY ANIMATION
16
HABITAT LOSS, DEGRADATION, AND FRAGMENTATION
  • The greatest threat to a species is the loss,
    degradation, and fragmentation of where it lives.

Figure 12-6
17
HABITAT LOSS, DEGRADATION, AND FRAGMENTATION
  • Reduction in ranges of four wildlife species,
    mostly due to habitat loss and overharvest.

Figure 12-7
18
Indian Tiger
Range 100 years ago
Range today (about 2,300 left)
19
Black Rhino
Range in 1700
Range today (about 3,600 left)
20
African Elephant
Probable range 1600
Range today
21
Asian or Indian Elephant
Former range
Range today (34,00054,000 left)
22
Case Study A Disturbing Message from the Birds
  • Human activities are causing serious declines in
    the populations of many bird species.

Figure 12-8
23
Case Study A Disturbing Message from the Birds
  • The majority of the worlds bird species are
    found in South America.
  • Threatened with habitat loss and invasive species.

24
INVASIVE SPECIES
OBJ 12.6
  • Many nonnative species provide us with food,
    medicine, and other benefits 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.
25
INVASIVE SPECIES
  • Many invasive species have been introduced
    intentionally.

26
INVASIVE SPECIES
OBJ 12.7
  • Many invasive species have been introduced
    unintentionally.

27
INVASIVE SPECIES
  • The Argentina fire ant was introduced to Mobile,
    Alabama in 1932 from South America.
  • Most probably from ships.
  • No natural predators.

28
INVASIVE SPECIES
OBJ 12.8
  • 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
29
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
30
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.

31
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.
32
DDT in fish-eating birds (ospreys)
25 ppm
DDT in large fish (needle fish) 2 ppm
DDT in small fish (minnows) 0.5 ppm
DDT in zooplankton 0.04 ppm
DDT in water 0.000003 ppm, or 3 ppt
33
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.

34
OVEREXPLOITATION
  • Rhinoceros are often killed for their horns and
    sold illegally on the black market for decorative
    and medicinal purposes.

35
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.

36
PROTECTING WILD SPECIES LEGAL AND ECONOMIC
APPROACHES
OBJ 12.9
  • 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.

37
Case Study The U.S. Endangered Species Act
OBJ 12.10
  • 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.

38
Case Study The U.S. Endangered Species Act
  • Biodiversity hotspots in relation to the largest
    concentrations of rare and potentially endangered
    species in the U.S.

39
Endangered Species
  • Because of scarcity of inspectors, probably no
    more than 1/10th of the illegal wildlife trade in
    the U.S. is discovered.

40
Endangered Species
  • Congress has amended the ESA to help landowners
    protect species on their land.
  • Some believe that the ESA should be weakened or
    repealed while others believe it should be
    strengthened and modified to focus on protecting
    ecosystems.
  • Many scientists believe that we should focus on
    protecting and sustaining biodiversity and
    ecosystem function as the best way to protect
    species.

41
How Would You Vote?
  • To conduct an instant in-class survey using a
    classroom response system, access JoinIn Clicker
    Content from the PowerLecture main menu for
    Living in the Environment.
  • Should the Endangered Species Act be modified to
    protect and sustain the nation's overall
    biodiversity?
  • a. No. Protecting entire habitats will only
    further interfere with the rights of landowners.
  • b. Yes. Protecting endangered habitats is more
    efficient and effective than saving individual
    species.

42
PROTECTING WILD SPECIES THE SANCTUARY APPROACH
  • The U.S. has set aside 544 federal refuges for
    wildlife, but many refuges are suffering from
    environmental degradation.

Pelican Island was the nations first wildlife
refuge.
43
PROTECTING WILD SPECIES THE SANCTUARY APPROACH
  • 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.

44
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).

45
Using Reconciliation Ecology to Protect Bluebirds
  • Putting up bluebird boxes with holes too small
    for (nonnative) competitors in areas where trees
    have been cut down have helped reestablish
    populations.

46
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.
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