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Chapter 6LectureOutline

Learning OutcomesAfter studying this chapter, you should be able to answer the following questions:

• What portion of the world’s original forests remain?• What activities threaten global forests? What steps can be

taken to preserve them?• Why is road construction a challenge to forest conservation?• Where are the world’s most extensive grasslands?• How are the world’s grasslands distributed, and what

activities degrade grasslands?• What are the original purposes of parks and nature

preserves in North America?• What is a wilderness? Why are wilderness areas both

important and controversial?• What are some steps to help restore natural areas?

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What a country chooses to save is what a country chooses to say about itself.

–Mollie Beatty, former director, U.S. Fish and Wildlife Service

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6.1 World Forests

• Forests and grasslands together occupy almost 60 percent of global land cover.

• These ecosystems provide many of our essential resources.• They also provide essential ecological services.

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Boreal and tropical forests are most abundant

• Old-growth forests are those that cover a large enough area and have been undisturbed by human activities long enough that trees can live out a natural life cycle.

• Some of the world’s most biologically diverse regions are undergoing rapid deforestation, including Southeast Asia and Central America.

• Forests are a huge carbon sink, storing some 422 billion metric tons of carbon in standing biomass.

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Forests provide many valuable products

• Wood plays a part in more activities of the modern economy than does any other commodity.

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Tropical forests are being cleared rapidlyCauses of deforestation

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Forest protection

• About 12 percent of all world forests are in some form of protected status, but the effectiveness of that protection varies greatly.

• Costa Rica has one of the best plans for forest guardianship in the world.

• Attempts are being made there not only to rehabilitate the land (make an area useful to humans) but also to restore the ecosystems to naturally occurring associations.

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Debt-for-nature swaps

• Banks, governments, and lending institutions now hold nearly $1 trillion in loans to developing countries.

• There is little prospect of ever collecting much of this debt, and banks are often willing to sell bonds at a steep discount—perhaps as little as 10 cents on the dollar.

• Conservation organizations buy debt obligations on the secondary market at a discount and then offer to cancel the debt if the debtor country agrees to protect or restore an area of biological importance.

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Temperate forests also are at risk• Many endemic species,

such as the northern spotted, are so highly adapted to the unique conditions of these ancient forests that they live nowhere else.

• Less than 10 percent of old-growth forest in the United States remains intact.

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Harvest methods

• Most lumber and pulpwood in the United States and Canada currently are harvested by clear-cutting, in which every tree in a given area is cut, regardless of size.

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Should we subsidize logging on public lands?

• People in the U.S. are calling for an end to all logging on federal lands because ecological services, from maintaining river levels for fish and irrigation to recreation, generate more revenue at lower costs.

• Many communities depend on logging jobs, but these jobs depend on subsidies.

• The federal government builds roads, manages forests, fights fires, and sells timber for less than the administrative costs of the sales.

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Fire management

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Ecosystem management

• Ecosystem management is an U.S. Forest Service policy that attempts to integrate sustainable ecological, economic, and social goals in a unified, systems approach.

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6.2 Grasslands

• Grasslands, chaparral, and open woodlands are attractive for human occupation, so they frequently are converted to cropland, urban areas, or other human-dominated landscapes.

• Worldwide the rate of grassland disturbance each year is three times that of tropical forest.

• Desertification is the process of conversion of once fertile land to desert.

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Overgrazing threatens many rangelands

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Some biomes are relatively unprotected.

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6.3 Parks and Preserves

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Marine ecosystems need greater protection

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Conservation and economicdevelopment can work together

• Ecotourism is tourism that is ecologically and socially sustainable.

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Species survival can dependon preserve size and shape

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Landscape Ecology

• A science that examines the relationship between spatial patterns and ecological processes

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Practice Quiz1. What do we mean by closed-canopy forest and old-growthforest?2. What land use is responsible for most forest losses in Africa?In Latin America? In Asia? (fig. 6.7).3. What is a debt-for-nature swap?4. Why is fire suppression a controversial strategy? Why are

forest thinning and salvage logging controversial?5. What portion of the United States’ public rangelands are inpoor or very poor condition due to overgrazing? Why do somegroups say grazing fees amount to a “hidden subsidy”?

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Practice Quiz continued…6. What is rotational grazing, and how does it mimic naturalprocesses?7. How do the size and design of nature preserves influence theireffectiveness? What do landscape ecologists mean by interiorhabitat and edge effects?8. What percentage of the earth’s land area has some sort of

protected status? How has the amount of protected areas changed globally (fig. 6.18)?

9. What is ecotourism, and why is it important?10. What is a biosphere reserve, and how does it differ from awilderness area or wildlife preserve?

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