1. Sustaining Biodiversity: The Species Approach
Chapter 11
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. Updates Online
The latest references for topics covered in this section can be found at the book companion website. Log in to the book’s e-resources page at to access InfoTrac articles.
InfoTrac: Domestic cats serve as add-on predators. Paducah Sun (Paducah, KY), July 26, 2006.
InfoTrac: Invasion of the habitat snatchers. Wichita Eagle, August 6, 2006.
InfoTrac: Group pulls for native Denali plants. Anchorage Daily News, June 26, 2006.
Union of Concerned Scientists: Invasive Species
PBS: Strange Days on Planet Earth
USGS: Nonindigenous Aquatic Species

4. 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 11-1

5. Animation: Humans Affect Biodiversity
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ANIMATION

6. 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.
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.

7. Global Extinction
Some animals have become prematurely extinct because of human activities.
Figure 11-2

8. Endangered and Threatened Species: Ecological Smoke Alarms
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

9. Figure 11.3
Endangered natural capital: species that are endangered or threatened with premature extinction largely because of human activities. Almost 30,000 of the world’s species and 1,260 of those in the United States are officially listed as being in danger of becoming extinct. Most biologists believe the actual number of species at risk is much larger.
Fig. 11-3, p. 224

10. SPECIES EXTINCTION
Some species have characteristics that make them vulnerable to ecological and biological extinction.
Figure 11-4

11. 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 world’s threatened species.
The 2004 Red List contains 15,589 species at risk for extinction.
Figure 11-5

12. Video: Penguin Rescue
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VIDEO
From ABC News, Biology in the Headlines, 2005 DVD.

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

14. SPECIES EXTINCTION
Scientists use models to estimate the risk of particular species becoming extinct or endangered.
Figure 11-6

15. 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).

16. 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

17. Animation: Habitat Loss and Fragmentation
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ANIMATION

18. HABITAT LOSS, DEGRADATION, AND FRAGMENTATION
The greatest threat to a species is the loss, degradation, and fragmentation of where it lives.
Figure 11-7

19. HABITAT LOSS, DEGRADATION, AND FRAGMENTATION
Reduction in ranges of four wildlife species, mostly due to habitat loss and overharvest.
Figure 11-8

20. Video: Bachelor Pad at the Zoo
PLAY
VIDEO
From ABC News, Biology in the Headlines, 2005 DVD.

21. Case Study: A Disturbing Message from the Birds
Human activities are causing serious declines in the populations of many bird species.
Figure 11-9

22. Video: Bird Species and Birdsongs
PLAY
VIDEO

23. Case Study: A Disturbing Message from the Birds
The majority of the world’s bird species are found in South America.
Threatened with habitat loss and invasive species.
Figure 11-10

24. INVASIVE SPECIES
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.
Figure 11-A

25. INVASIVE SPECIES
Many invasive species have been introduced intentionally.
Figure 11-11

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

27. INVASIVE SPECIES
The Argentina fire ant was introduced to Mobile, Alabama in 1932 from South America.
Most probably from ships.
No natural predators.
Figure 11-12

28. 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

29. Ecosystems Vulnerable
Characteristics of
Successful
Invader Species
Characteristics of
Ecosystems Vulnerable
to Invader Species
• 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
• 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
Figure 11.13
Threats to natural capital: some general characteristics of successful invasive species and ecosystems vulnerable to invading species.
Fig , 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.
Figure 11-15

32. 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.

33. OVEREXPLOITATION
Rhinoceros are often killed for their horns and sold illegally on the black market for decorative and medicinal purposes.
Figure 11-16

34. 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

35. PROTECTING WILD SPECIES: LEGAL AND ECONOMIC APPROACHES
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.

36. Case Study: The U.S. Endangered Species Act
One of the world’s 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.

37. 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.
Figure 11-18

38. Endangered Species
Because of scarcity of inspectors, probably no more than 1/10th of the illegal wildlife trade in the U.S. is discovered.
Figure 11-19

39. 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.

40. 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.

41. 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 nation’s first wildlife refuge.
Figure 11-20

42. 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.

43. Video: Hsing Hsing Dies
PLAY
VIDEO
From ABC News, Biology in the Headlines, 2005 DVD.

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.
Figure 11-B

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.
Figure 11.21
Individuals matter: ways to help premature extinction of species. QUESTIONS: Which two of these actions do you think are the most important? Which of these actions do you plan to take?
Fig , p. 246