1. Sustaining Biodiversity: The Ecosystems Approach
Chapter 6
Sustaining Biodiversity: The Ecosystems Approach

2. Chapter Overview Questions
How have human activities affected the earth’s biodiversity?
How should forest resources be used, managed, and sustained globally and in the United States?
How serious is tropical deforestation, and how can we help sustain tropical forests?
How should rangeland resources be used, managed, and sustained?

3. Chapter Overview Questions (cont’d)
What problems do parks face, and how should we manage them?
How should we establish, design, protect, and manage terrestrial nature reserves?
What is wilderness, and why is it important?
What is ecological restoration, and why is it important?
What can we do to help sustain the earth’s terrestrial biodiversity?

4. 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: Cloud over Puerto Rico rain forest. Chicago Tribune, March 20, 2006.
InfoTrac: Can't log the forest for the trees? Roger Harris. American Scientist, March-April 2006 v94 i2 p120(2).
InfoTrac: The cry of the wild. Thomas L. Friedman. The New York Times, June 28, 2006 pA21(L).
NASA: Tropical Deforestation
Greenpeace: Eating Up the Amazon

5. Core Case Study: Reintroducing Wolves to Yellowstone
Endangered Species
two million wolves were destroyed.
Keystone Species
Keeps prey away from open areas near stream banks.
Vegetation reestablishes.
Species diversity expands.

6. HUMAN IMPACTS ON TERRESTRIAL BIODIVERSITY
We have depleted and degraded some of the earth’s biodiversity and these threats are expected to increase.

7. Agriculture, industry, economic production and consumption, recreation
Human Population
Size and resource use
Human Activities
Agriculture, industry, economic
production and consumption, recreation
Direct Effects
Degradation and destruction
of natural ecosystems
Changes in number and
distribution of species
Figure 10.2
Natural capital degradation: major connections between human activities and the earth’s biodiversity.
Alteration of natural chemical
cycles and energy flows
Pollution of air, water,
and soil
Indirect Effects
Climate
change
Loss of
Biodiversity

8. Why Should We Care About Biodiversity?
Use Value: For the usefulness in terms of economic and ecological services.
Nonuse Value: existence, aesthetics, bequest for future generations.

9. MANAGING AND SUSTAINING FORESTS
Forests provide a number of ecological and economic services that researchers have attempted to estimate their total monetary value.

10. Support energy flow and chemical cycling
Natural Capital
Forests
Ecological
Services
Economic
Services
Support energy flow and chemical cycling
Reduce soil erosion
Absorb and release water
Purify water and air
Influence local and regional climate
Store atmospheric carbon
Provide numerous wildlife habitats
Fuelwood
Lumber
Pulp to make paper
Mining
Livestock grazing
Recreation
Jobs
Figure 10.4
Natural capital: major ecological and economic services provided by forests. QUESTION: Which two ecological services and which two economic services do you think are the most important?

11. Types of Forests
Old-growth forest: uncut or regenerated forest that has not been seriously disturbed for several hundred years.
22% of world’s forest.
Hosts many species with specialized niches.

12. Types of Forests
Second-growth forest: a stand of trees resulting from natural secondary succession.
Tree plantation: planted stands of a particular tree species.

13. Weak trees removed Clear cut Seedlings planted 25 15 10 30
Years of growth 5
Figure 10.6
Natural capital degradation: Short (25- to 30-year) rotation cycle of cutting and regrowth of a monoculture tree plantation in modern industrial forestry. In tropical countries, where trees can grow more rapidly year-round, the rotation cycle can be 6–10 years. Old-growth or secondary forests are clear-cut to provide land for growing most tree plantations.

14. Global Outlook: Extent of Deforestation
Human activities have reduced the earth’s forest cover by as much as half.
Losses are concentrated in developing countries.

15. Natural Capital Degradation
Deforestation
• Decreased soil fertility from erosion
• Runoff of eroded soil into aquatic systems
• Premature extinction of species with
specialized niches
• Loss of habitat for native species and migratoryspecies such as birds and butterflies
• Regional climate change from extensive clearing
• Release of CO2 into atmosphere
• Acceleration of flooding
Figure 10.7
Natural capital degradation: harmful environmental effects of deforestation that can reduce biodiversity and the ecological services provided by forests (Figure 10-4, left). QUESTION: What are the two direct and two indirect effects of your lifestyle on deforestation?

16. 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 there be a global effort to sharply reduce the cutting of old-growth forests?
a. Yes. Old-growth forests can only be saved by rapid international action and the setting aside of large reserves of the forests.
b. No. Only local citizens and not global efforts led by the UN can save these forests.

17. Case Study: Deforestation and the Fuelwood Crisis
Almost half the people in the developing world face a shortage of fuelwood and charcoal.
In Haiti, 98% of country is deforested.
MIT scientist has found a way to make charcoal from spent sugarcane.

18. Harvesting Trees
Building roads into previously inaccessible forests paves the way for fragmentation, destruction, and degradation.

19. Cleared plots for grazing Highway Highway
Cleared plots for agriculture
Old growth
Figure 10.8
Natural capital degradation: Building roads into previously inaccessible forests paves the way to fragmentation, destruction, and degradation.

20. Harvesting Trees
Trees can be harvested individually from diverse forests (selective cutting), an entire forest can be cut down (clear cutting), or portions of the forest is harvested (e.g. strip cutting).

21. (a) Selective cutting
Figure 10.9
Major tree harvesting methods.

22. (b) Clear-cutting
Figure 10.9
Major tree harvesting methods.

23. (c) Strip cutting Uncut Cut 1 year ago Dirt road Cut 3–10 years ago
Figure 10.9
Major tree harvesting methods.
Stream

24. Harvesting Trees
Effects of clear-cutting in the state of Washington, U.S.

25. Clear-Cutting Forests
Trade-Offs
Clear-Cutting Forests
Advantages
Disadvantages
Higher timber yields
Maximum profits in shortest time
Can reforest with fast-growing trees
Short time to establish new stand of trees
Needs less skill and planning
Good for tree species needing full or moderate sunlight
Reduces biodiversity
Disrupts ecosystem processes
Destroys and fragments wildlife habitats
Leaves large openings
Increases water pollution, flooding, and erosion on steep slopes
Eliminates most recreational value
Figure 10.11
Trade-offs: advantages and disadvantages of clear-cutting forests. QUESTION: Which single advantage and which single disadvantage do you think are the most important?

26. Solutions We can use forests more sustainably by emphasizing:
Economic value of ecological services.
Harvesting trees no faster than they are replenished.
Protecting old-growth and vulnerable areas.

27. • Identify and protect forest areas high in biodiversity
Solutions
Sustainable Forestry
• Identify and protect forest areas high in biodiversity
• Grow more timber on long rotations
• Rely more on selective cutting and strip cutting
• Stop clear-cutting on steep slopes
• Cease logging of old-growth forests
• Prohibit fragmentation of remaining large blocks offorest
• Sharply reduce road building into uncut forest areas
• Leave most standing dead trees and fallen timber for wildlife habitat and nutrient recycling
• Certify timber grown by sustainable methods
• Include ecological services of forests in estimating their economic value
• Plant tree plantations on deforested and degraded land
• Shift government subsidies from harvesting trees to planting trees
Figure 10.12
Solutions: ways to manage forests more sustainably. QUESTION: Which three of these solutions do you think are the most important?

28. CASE STUDY: FOREST RESOURCES AND MANAGEMENT IN THE U.S.
U.S. forests cover more area than in 1920.
Since the 1960’s, an increasing area of old growth and diverse second-growth forests have been clear-cut.
Often replace with tree farms.
Decreases biodiversity.
Disrupts ecosystem processes.

29. Types and Effects of Forest Fires
Depending on their intensity, fires can benefit or harm forests.
Burn away flammable ground material.
Release valuable mineral nutrients.

30. Solutions: Controversy Over Fire Management
To reduce fire damage:
Set controlled surface fires.
Allow fires to burn on public lands if they don’t threaten life and property.
Clear small areas around property subject to fire.

31. Solutions: Controversy Over Fire Management
In 2003, U.S. Congress passed the Healthy Forest Restoration Act:
Allows timber companies to cut medium and large trees in 71% of the national forests.
In return, must clear away smaller, more fire-prone trees and underbrush.
Some forest scientists believe this could increase severe fires by removing fire resistant trees and leaving highly flammable slash.

32. 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.
Do you support repealing or modifying the Healthy Forests Restoration Act of 2003?
a. Yes. Local officials and scientists are probably most qualified to manage their local forests.
b. No. The initiative favors the timber companies rather than effectively protecting and managing the forests.

33. Controversy over Logging in U.S. National Forests
There has been an ongoing debate over whether U.S. national forests should be primarily for:
Timber.
Ecological services.
Recreation.
Mix of these uses.

34. Logging in U.S. National Forests
Trade-Offs
Logging in U.S. National Forests
Advantages
Disadvantages
Helps meet country’s timber needs
Cut areas grow back
Keeps lumber and paper prices down
Provides jobs in nearby communities
Promotes economic growth in nearby communities
Provides only 4% of timber needs
Ample private forest land to meet timber needs
Has little effect on timber and paper prices
Damages nearby rivers and fisheries
Recreation in national forests provides more local jobs and income for local communities than logging
Decreases recreational opportunities
Figure 10.14
Trade-offs: advantages and disadvantages of allowing logging in U.S. national forests. QUESTION: Which two advantages and which two disadvantages do you think are the most important?

35. Solutions: Reducing Demand for Harvest Trees
Tree harvesting can be reduced by wasting less wood and making paper and charcoal fuel from fibers that do not come from trees.
Kenaf is a promising plant for paper production.

36. American Forests in a Globalized Economy
Timber from tree plantations in temperate and tropical countries is decreasing the need for timber production in the U.S.
This could help preserve the biodiversity in the U.S. by decreasing pressure to clear-cut old-growth and second-growth forests.
This may lead to private land owners to sell less profitable land to developers.
Forest management policy will play a key role.

37. CASE STUDY: TROPICAL DEFORESTATION
Large areas of ecologically and economically important tropical forests are being cleared and degraded at a fast rate.

38. CASE STUDY: TROPICAL DEFORESTATION
At least half of the world’s terrestrial plant and animal species live in tropical rain forests.
Large areas of tropical forest are burned to make way for cattle ranches and crops.

39. Why Should We Care about the Loss of Tropical Forests?
About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical forests.

40. Rauvolfia Rauvolfia sepentina, Southeast Asia Tranquilizer, high
Figure 10.18
Natural capital: nature’s pharmacy. Parts of these and a number of other plants and animals (many of them found in tropical forests) are used to treat a variety of human ailments and diseases. Nine of the ten leading prescription drugs originally came from wild organisms. About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical forests. Despite their economic and health potential, fewer than 1% of the estimated 125,000 flowering plant species in tropical forests (and a mere 1,100 of the world’s 260,000 known plant species) have been examined for their medicinal properties. Once the active ingredients in the plants have been identified, they can usually be produced synthetically. Many of these tropical plant species are likely to become extinct before we can study them.
Rauvolfia
Rauvolfia sepentina,
Southeast Asia
Tranquilizer, high
blood pressure
medication

41. Foxglove Digitalis purpurea, Europe Digitalis for heart failure
Figure 10.18
Natural capital: nature’s pharmacy. Parts of these and a number of other plants and animals (many of them found in tropical forests) are used to treat a variety of human ailments and diseases. Nine of the ten leading prescription drugs originally came from wild organisms. About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical forests. Despite their economic and health potential, fewer than 1% of the estimated 125,000 flowering plant species in tropical forests (and a mere 1,100 of the world’s 260,000 known plant species) have been examined for their medicinal properties. Once the active ingredients in the plants have been identified, they can usually be produced synthetically. Many of these tropical plant species are likely to become extinct before we can study them.
Foxglove
Digitalis purpurea,
Europe
Digitalis for heart failure

42. Pacific yew Taxus brevifolia, Pacific Northwest Ovarian cancer
Figure 10.18
Natural capital: nature’s pharmacy. Parts of these and a number of other plants and animals (many of them found in tropical forests) are used to treat a variety of human ailments and diseases. Nine of the ten leading prescription drugs originally came from wild organisms. About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical forests. Despite their economic and health potential, fewer than 1% of the estimated 125,000 flowering plant species in tropical forests (and a mere 1,100 of the world’s 260,000 known plant species) have been examined for their medicinal properties. Once the active ingredients in the plants have been identified, they can usually be produced synthetically. Many of these tropical plant species are likely to become extinct before we can study them.
Pacific yew
Taxus brevifolia,
Pacific Northwest
Ovarian cancer

43. Cinchona Cinchona ledogeriana, South America
Figure 10.18
Natural capital: nature’s pharmacy. Parts of these and a number of other plants and animals (many of them found in tropical forests) are used to treat a variety of human ailments and diseases. Nine of the ten leading prescription drugs originally came from wild organisms. About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical forests. Despite their economic and health potential, fewer than 1% of the estimated 125,000 flowering plant species in tropical forests (and a mere 1,100 of the world’s 260,000 known plant species) have been examined for their medicinal properties. Once the active ingredients in the plants have been identified, they can usually be produced synthetically. Many of these tropical plant species are likely to become extinct before we can study them.
Cinchona
Cinchona ledogeriana,
South America
Quinine for malaria treatment

44. Rosy periwinkle Cathranthus roseus, Madagascar Hodgkin's disease,
Figure 10.18
Natural capital: nature’s pharmacy. Parts of these and a number of other plants and animals (many of them found in tropical forests) are used to treat a variety of human ailments and diseases. Nine of the ten leading prescription drugs originally came from wild organisms. About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical forests. Despite their economic and health potential, fewer than 1% of the estimated 125,000 flowering plant species in tropical forests (and a mere 1,100 of the world’s 260,000 known plant species) have been examined for their medicinal properties. Once the active ingredients in the plants have been identified, they can usually be produced synthetically. Many of these tropical plant species are likely to become extinct before we can study them.
Rosy periwinkle
Cathranthus roseus,
Madagascar
Hodgkin's disease,
lymphocytic leukemia

45. Neem tree Azadirachta indica, India Treatment of many
Figure 10.18
Natural capital: nature’s pharmacy. Parts of these and a number of other plants and animals (many of them found in tropical forests) are used to treat a variety of human ailments and diseases. Nine of the ten leading prescription drugs originally came from wild organisms. About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical forests. Despite their economic and health potential, fewer than 1% of the estimated 125,000 flowering plant species in tropical forests (and a mere 1,100 of the world’s 260,000 known plant species) have been examined for their medicinal properties. Once the active ingredients in the plants have been identified, they can usually be produced synthetically. Many of these tropical plant species are likely to become extinct before we can study them.
Neem tree
Azadirachta indica,
India
Treatment of many
diseases, insecticide,
spermicide

46. Causes of Tropical Deforestation and Degradation
Tropical deforestation results from a number of interconnected primary and secondary causes.

47. Secondary Causes Basic Causes • Oil drilling • Mining
• Flooding from dams
• Tree plantations
• Cattle ranching
• Cash crops
• Settler farming
• Fires
• Logging
• Roads
Secondary Causes
Figure 10.19
Natural capital degradation: major interconnected causes of the destruction and degradation of tropical forests. The importance of specific secondary causes varies in different parts of the world.
• Not valuing
ecological services
• Exports
• Government policies
• Poverty
• Population growth
Basic Causes

48. Sustaining Tropical Forests
Solutions
Sustaining Tropical Forests
Prevention
Restoration
Protect most diverse and endangered areas
Educate settlers about sustainable agriculture and forestry
Phase out subsidies that encourage unsustainable forest use
Add subsidies that encourage sustainable forest use
Protect forests with debt-for-nature swaps and conservation easements
Certify sustainably grown timber
Reduce illegal cutting
Reduce poverty
Slow population growth
Reforestation
Rehabilitation of degraded areas
Concentrate farming and ranching on already-cleared areas
Figure 10.20
Solutions: ways to protect tropical forests and use them more sustainably. QUESTION: Which three of these solutions do you think are the most important?

49. Kenya’s Green Belt Movement: Individuals Matter
Wangari Maathai founded the Green Belt Movement.
The main goal is to organize poor women to plant (for fuelwood) and protect millions of trees.
In 2004, awarded Nobel peace prize.

50. MANAGING AND SUSTAINING GRASSLANDS
Almost half of the world’s livestock graze on natural grasslands (rangelands) and managed grasslands (pastures).
We can sustain rangeland productivity by controlling the number and distribution of livestock and by restoring degraded rangeland.

51. MANAGING AND SUSTAINING GRASSLANDS
Overgrazing (left) occurs when too many animals graze for too long and exceed carrying capacity of a grassland area.

52. MANAGING AND SUSTAINING GRASSLANDS
Example of restored area along the San Pedro River in Arizona after 10 years of banning grazing and off-road vehicles.

53. Case Study: Grazing and Urban Development in the American West
Ranchers, ecologists, and environmentalists are joining together to preserve the grasslands on cattle ranches.
Paying ranchers conservation easements (barring future owners from development).
Pressuring government to zone the land to prevent development of ecologically sensitive areas.

54. NATIONAL PARKS
Countries have established more than 1,100 national parks, but most are threatened by human activities.
Local people invade park for wood, cropland, and other natural resources.
Loggers, miners, and wildlife poachers also deplete natural resources.
Many are too small to sustain large-animal species.
Many suffer from invasive species.

55. Case Study: Stresses on U.S. National Parks
Overused due to popularity.
Inholdings (private ownership) within parks threaten natural resources.
Air pollution.

56. Suggestions for sustaining and expanding the national park system in the U.S.

57. • Integrate plans for managing parks and nearby federal lands
Solutions
National Parks
• Integrate plans for managing parks and nearby federal lands
• Add new parkland near threatened parks
• Buy private land inside parks
• Locate visitor parking outside parks and use shuttle buses for entering and touring heavily used parks
• Increase funds for park maintenance and repairs
• Survey wildlife in parks
• Raise entry fees for visitors and use funds for park management and maintenance
• Limit the number of visitors to crowded park areas
• Increase the number and pay of park rangers
• Encourage volunteers to give visitor lectures and tours
• Seek private donations for park maintenance and repairs
Figure 10.24
Solutions: suggestions for sustaining and expanding the national park system in the United States. QUESTION: Which two of these solutions do you think are the most important? (Data from Wilderness Society and National Parks and Conservation Association)

58. NATURE RESERVES
Ecologists call for protecting more land to help sustain biodiversity, but powerful economic and political interests oppose doing this.
Currently 12% of earth’s land area is protected.
Only 5% is strictly protected from harmful human activities.
Conservation biologists call for full protection of at least 20% of earth’s land area representing multiple examples of all biomes.

59. 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 at least 20% of the Earth's land area be strictly protected from economic development?
a. No. Such protections would encourage people to poach and illegally extract resources from the expanded reserves.
b. Yes. The project is desperately needed to protect the Earth's biodiversity.

60. NATURE RESERVES
Large and medium-sized reserves with buffer zones help protect biodiversity and can be connected by corridors.
Costa Rica has consolidated its parks and reserves into 8 megareserves designed to sustain 80% if its biodiversity.

61. Cordillera Volcanica Central
Guanacaste
Nigaragua
Caribbean Sea
Llanuras de
Tortuguero
Costa
Rica
La Amistad
Arenal
Bajo
Tempisque
Panama
Cordillera Volcanica Central
Figure 10.B
Solutions: Costa Rica has consolidated its parks and reserves into eight megareserves designed to sustain about 80% of the country’s rich biodiversity.
Pacifico Central
Peninsula Osa
Pacific Ocean

62. NATURE RESERVES
A model biosphere reserve that contains a protected inner core surrounded by two buffer zones that people can use for multiple use.

63. Biosphere Reserve Core area Buffer zone 1 Buffer zone 2 Tourism and
Figure 10.25
Solutions: a model biosphere reserve. Each reserve contains a protected inner core surrounded by two buffer zones that local and indigenous people can use for sustainable logging, food growing, cattle grazing, hunting, fishing, and ecotourism.
Tourism and
education center
Human
Settlements
Research
Station

64. NATURE RESERVES
Geographic Information System (GIS) mapping can be used to understand and manage ecosystems.
Identify areas to establish and connect nature reserves in large ecoregions to prevent fragmentation.
Developers can use GIS to design housing developments with the least environmental impact.

65. NATURE RESERVES
We can prevent or slow down losses of biodiversity by concentrating efforts on protecting global hot spots where significant biodiversity is under immediate threat.
Conservation biologists are helping people in communities find ways to sustain local biodiversity while providing local economic income.

66. 34 hotspots identified by ecologists as important and endangered centers of biodiversity.

67. NATURE RESERVES
Wilderness is land legally set aside in a large enough area to prevent or minimize harm from human activities.
Only a small percentage of the land area of the United States has been protected as wilderness.

68. ECOLOGICAL RESTORATION
Restoration: trying to return to a condition as similar as possible to original state.
Rehabilitation: attempting to turn a degraded ecosystem back to being functional.
Replacement: replacing a degraded ecosystem with another type of ecosystem.
Creating artificial ecosystems: such as artificial wetlands for flood reduction and sewage treatment.

69. ECOLOGICAL RESTORATION
Five basic science-based principles for ecological restoration:
Identify cause.
Stop abuse by eliminating or sharply reducing factors.
Reintroduce species if necessary.
Protect area form further degradation.
Use adaptive management to monitor efforts, assess successes, and modify strategies.

70. Will Restoration Encourage Further Destruction?
There is some concern that ecological restoration could promote further environmental destruction and degradation.
Suggesting that any ecological harm can be undone.
Preventing ecosystem damage is far cheaper than ecological restoration.

71. 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 we mount a massive effort to restore ecosystems we have degraded even though this will be quite costly?
a. No. Less expensive alternatives, such as remediation, replacement, and the creation of artificial ecosystems, should be readily considered.
b. Yes. Alternatives will probably not achieve the same biodiversity as ecological restoration.

72. WHAT CAN WE DO? Eight priorities for protecting biodiversity:
Take immediate action to preserve world’s biological hot spots.
Keep intact remaining old growth.
Complete mapping of world’s biodiversity for inventory and decision making.
Determine world’s marine hot spots.
Concentrate on protecting and restoring lake and river systems (most threatened ecosystems).

73. WHAT CAN WE DO?
Ensure that the full range of the earths ecosystems are included in global conservation strategy.
Make conservation profitable.
Initiate ecological restoration products to heal some of the damage done and increase share of earth’s land and water allotted to the rest of nature.

74. Sustaining Terrestrial Biodiversity
What Can You Do?
Sustaining Terrestrial Biodiversity
• Adopt a forest.
• Plant trees and take care of them.
• Recycle paper and buy recycled paper products.
• Buy sustainable wood and wood products.
• Choose wood substitutes such as bamboo furniture and recycled plastic outdoor furniture, decking, and fencing.
• Restore a nearby degraded forest or grassland.
• Landscape your yard with a diversity of plants natural to the area.
• Live in town because suburban sprawl reduces biodiversity.
Figure 10.27
Individuals matter: ways to help sustain terrestrial biodiversity.