Chapter Summary: Chapter 6
Sustaining Biodiversity: The Ecosystem Approach
6-1 What are the major threats to forest ecosystems?
Human activities have caused or contributed to the premature extinction of hundreds of species. They have, in
addition, degraded from 50–83% of the earth’s land surface. CONCEPT 6-1 Unsustainable cutting and burning of
forests, especially in tropical areas, is a potentially catastrophic problem because of the vital ecological services at
risk and the growing contribution to projected climate change.
1. Distinguish between old-growth forest and second-growth forest. List five reasons why forests are
commercially important. List five reasons why forests are ecologically important.
2. List three ways to help reduce the interlocking problems of tropical deforestation and the fuelwood
crisis.
3. State the rates of tropical deforestation. List five ways that tropical forests touch lives in the temperate
zones. List three factors underlying causes of tropical deforestation. List eight human activities that
actually destroy the tropical forests. List five ways that tropical deforestation could be reduced.
4. Describe the advantages and disadvantages of clear-cutting a forest ecosystem.
5. Describe the natural capital of forests in terms of ecological and economic services.
6-2 How should we manage and sustain forests?
In order to preserve natural environments, countries must establish and manage nature reserves as well as wilderness
areas. CONCEPT 6-2 We can sustain forests by emphasizing the economic value of their ecological services,
removing government subsidies that hasten their destruction, protecting old-growth forests, harvesting trees no faster
than they are replenished, and planting trees.
6. Describe the steps in forest management. List and summarize the goals for three types of tree
harvesting.
7. Define and describe at least seven characteristics of sustainable forestry.
6-3 How should we manage and sustain parks and nature reserves?
Sustainably managing and protecting wilderness helps preserve large areas of biodiversity. CONCEPT 6-3
Sustaining biodiversity will require more effective protection of existing parks and nature reserves, as well as the
protection of much more of the earth's remaining undisturbed land areas.
8. Briefly describe the extent of national parks worldwide. Describe a major problem of national parks.
State three steps that could improve the national park system. Evaluate the wolf controversy, take a
stand, and defend it.
9. Define wilderness. Describe a biosphere reserve. State one problem of wilderness areas and describe
how that problem could be managed better.
10. Compare the status of U.S. forests from 1900 and the present. Summarize how U.S. forests are
currently managed. List ways environmentalists recommend to reform federal forest management,
including: (a) two changes in resource-use practices, (b) three economic strategies, and (c) three
political strategies.
6-4 What is the ecosystem approach to sustaining terrestrial biodiversity?
We must focus on protecting and sustaining ecosystems and the biodiversity within them rather than on saving
individual species. CONCEPT 6-4 We can help to sustain terrestrial biodiversity by identifying and protecting
severely threatened areas (biodiversity hotspots), restoring damaged ecosystems, and sharing as much of the earth's
land as possible with other species.
11. What is a biodiversity hotspot? Give three supporting reasons why it is important to protect such areas.
12. Define and give three examples of ecological restoration.
6-5 How can we protect and sustain marine biodiversity?
Marine biodiversity must be protected in all ocean zones through marine sanctuaries and integrated coastal
management. CONCEPT 6-5 We can help sustain marine biodiversity by using laws and economic incentives to
protect species, setting aside marine reserves to protect ecosystems, and using community-based integrated coastal
management.
13. Summarize ways to globally manage marine fisheries to prevent over fishing.
14. Define the importance of aquatic biodiversity and describe three ways to protect and sustain marine
biodiversity.
6-6 How can we protect and sustain freshwater biodiversity?
Everything that is done on land and in the water has some effect on freshwater aquatic systems, so they must be
protected through laws, economic incentives, and restoration efforts. CONCEPT 6-6 We can help to sustain
freshwater biodiversity by protecting the watersheds of lakes and streams, preserving wetlands, and restoring
degraded freshwater systems.
15. Define the importance of aquatic biodiversity and describe three ways to protect and sustain freshwater
biodiversity.
16. Describe three ways that freshwater ecosystems are threatened.
6-7 What should be our priorities for sustaining terrestrial and aquatic biodiversity?
Lessons from ecology can help us in sustaining the earth’s biodiversity as we live upon it. We must understand our
dependence on the earth and sun; understand that everything is inter-dependent; maximize protection of ecosystems;
foresee and provide for our actions, and discontinue depleting and degrading our environment. CONCEPT 6-7 We
can help to sustain the world's biodiversity by mapping it, protecting biodiversity hotspots, creating large terrestrial
and aquatic reserves, and carrying out ecological restoration of degraded terrestrial and aquatic ecosystems.
17. List and briefly explain four of the priorities for protecting most of the world’s remaining ecosystems
as proposed by Edward O. Wilson.