1. ENVIRONMENTAL SCIENCE
CHAPTER 9: Sustaining Biodiversity: The Ecosystem Approach

2. Wangari Maathai and the Green Belt Movement
Began in Kenya in 1977
Organizes poor women in rural Kenya
50,000 members protect forests
Planted 20 million trees
Fruits
Building materials
Firewood
Similar programs in 30 African countries
2004: Nobel Peace Prize

3. http://www.greenbeltmovement.org/ Watch second video

4. 9-1 What Are Major Threats to Forest Ecosystems?
Concept 9-1 Ecologically valuable forest ecosystems are being cut and burned at unsustainable rates in many parts of the world.

5. Types of Forests
Forests cover 30% of earth’s land surface
Old-growth forests: uncut or regenerated primary forest that has not been seriously disturbed by human activities or natural disasters for several hundred years or more
Second-growth forests: a stand of trees resulting from secondary ecological succession. Develop after trees have been removed by human activities such as clear cutting for timber or cropland or by natural forces such as fire, hurricanes, or volcanic eruption
Tree plantation; tree farm; commercial forest

6. Old growth forest in the US state of Washington’s Olympic National Forest
Fig. 9-2, p. 180

7. rapidly year round so rotation cycle can be 6-10 years.
Short (25- to 30- year rotation cycle of cutting and regrowth of a monoculture tree
plantation in modern industrial forestry. In tropical countries, trees grow more
rapidly year round so rotation cycle can be 6-10 years.
Fig. 9-3, p. 180

8. Old growth or second growth forest are clear cut to provide land for growing most
tree plantations
Fig. 9-3, p. 180

9. ital Forests Ecological Economic Services Services
pFigure 9.4: Major ecological and economic services provided by forests (Concept 9-1).
Question: Which two ecological services and which two economic services do you
think are the most important?
ital
Forests
Ecological
Services
Economic
Services
Support energy flow and chemical cycling
Fuelwood
Lumber
Reduce soil erosion
Pulp to make
paper
Absorb and release water
Purify water and air
Mining
Figure 9.4: Major ecological and economic services provided by forests (Concept 9-1).
Question: Which two ecological services and which two economic services do you
think are the most important?
Livestock
grazing
Influence local and regional climate
Store atmospheric carbon
Recreation
Provide numerous wildlife habitats
Jobs
Fig. 9-4, p. 181

10. Science Focus: Putting a Price Tag on Nature’s Ecological Services
Estimated value of earth’s ecological services
$33.2 trillion per year
$4.7 trillion per year for forests
This is hundreds of times the economic value
Need to start factoring values into land use
Ecological services can be a sustainable source of ecological income

11. Estimated annual global economic values of some ecological services provided by forests compared to the raw materials they produce (in billions of dollars).
Fig. 9-A, p. 181

12. Harvest Methods Step one: build roads Erosion Invasive species
Open up for human invasion
Step two: logging operations
Selective cutting: intermediate aged or mature trees in an uneven aged forest are cut singly or in small groups (Fig 9-6a)
Clear cutting: remove all the trees from an area
Strip cutting: involves clear cutting a strip of trees along the contour of the land within a corridor narrow enough the allow natural regeneration within a few years

13. Cleared plots for grazing New highway Highway Cleared plots
for agriculture
Old growth
Figure 9.5: Natural capital degradation: Building roads into previously inaccessible forests is the first step to providing timber, but it also
paves the way to fragmentation, destruction, and degradation of forest ecosystems.
Fig. 9-5, p. 182

14. (a) Selective cutting Clear stream
Major tree harvesting methods. If you were cutting trees in a forest you owned
which method would you choose and why?
(a) Selective cutting
Figure 9.6: Major tree harvesting methods.
Question: If you were cutting trees in a forest you owned, which method would you choose and why?
Clear
stream
Fig. 9-6, p. 182

15. (b) Clear-cutting Muddy stream
Figure 9.6: Major tree harvesting methods.
Question: If you were cutting trees in a forest you owned, which method would you choose and why?
Muddy
stream
Fig. 9-6, p. 182

16. (c) Strip cutting Cut 1 Uncut year ago Dirt road Cut 3–10 years ago
Figure 9.6: Major tree harvesting methods.
Question: If you were cutting trees in a forest you owned, which method would you choose and why?
Clear
stream
Fig. 9-6, p. 182

17. Clear cut logging in the US state of Washington
Fig. 9-7, p. 182

18. Forests and Fires Surface fires Burn only undergrowth and leaf litter
May kill seedlings and small trees but spare most mature trees; allow most wild animals to escape
Cool fire
Ecological benefits: help prevent more destructive fires, free mineral nutrients, release certain seeds and stimulate germination of some tree seeds, help control diseases and insects

19. Crown fires Burn the entire tree Hot fire
Occur in forests with lack of surface fires

20. Type of fire?
Surface fires usually burn only undergrowth and leaf litter on a forest floor.
Fig. 9-8, p. 183

21. Type of
fire?
Fig. 9-8, p. 183

22. Loss of Original Forests
Deforestation
Over past 8,000 years, human activities have reduced the earth’s forest by 46%, most of this loss since since 1950
Most in tropical areas, developing countries
Estimated loss of 40% intact forests within next 20 years
Deforestation= temporary or permanent removal of large expanses of forest for agriculure, settlements, or other uses

23. Extreme tropical deforestation in Chiang Mai,Thailand.
What do you think will happen to the dried out topsoil when the winds come?
How does the term ecological tipping point apply here?
Such clearing of trees, which absorb carbon dioxide as they grow, contributes to projected climate change. It also dehydrates the soil by exposing it to sunlight. The dry topsoil can then blow away, which can lead to irreversible ecological tipping point beyond which a forest cannot be reestablished in the area.
Fig. 9-9, p. 184

24. Fig. 9-10, p. 184

25. Good News on Forests
2000–2007 net total forested area stabilized or increased
Most of the increase due to tree plantations
Net loss of terrestrial biodiversity

26. Return of Forests in the United States (1)
U.S. forests
Cover ~30% of land
Contain ~80% of wildlife species
Supply ~67% of nation’s surface water
Forest cover greater now than in 1920
Secondary succession

27. Return of Forests in the United States (2)
Second- and third-growth forests fairly diverse
More wood grown than cut
40% of forests in National Forest System
Some forests transformed into tree plantations

28. Tropical Forests Cover 6% of earth’s land area
Habitat for 50% of terrestrial plants and animals
Vulnerable to extinction – specialized niches
Rapid loss of 50,000–170,000 km2 per year
Some second-growth forests
Tropical forests once covered at least twice as much land area as they do today
Brazil, for example, has more than 30% of world’s remaining tropical rain forest in its vast Amazon basin
Second growth forests do not have same biodiversity as old-growth forests

29. Causes of Tropical Forest Deforestation and Degradation
Population growth and poverty
Economic reasons
Logging
Ranching
Farming
Government subsidies
Fires raise temperatures and reduce rainfall
Government subsidies can accelerate deforestation by reducing the costs of timber harvesting, cattle grazing, and establishing vast plantations of crops such as soybeans and oil palms

30. Natural Capital Degradation
Major Causes of the Destruction and Degradation of Tropical Forests
Basic Causes
Secondary Causes
Not valuing ecological services
Crop and timber exports
Government policies
Poverty
Population growth
Roads
Fires
Settler farming
Cash crops
Cattle ranching
Logging
Tree plantations
Cattle ranching
Tree plantations
Logging
Cash crops
Settler farming
Figure 9.11: Major interconnected causes of the destruction and degradation of tropical forests. The importance
of specific secondary causes varies in different parts of the world. Question: If we could eliminate the basic causes,
which if any of the secondary causes might automatically be eliminated?
Fires
Roads
Fig. 9-11, p. 186

31. What’s going on in this picture?
Brazil’s Amazon basin
What’s going on in this picture?
Large areas of tropical forest in Brazil’s Amazon basin are burned each year to make way for cattle ranches, plantation crops, and small scale farms.
Fig. 9-12, p. 187

32. 9-2 How Should We Manage and Sustain Forests?
Concept 9-2 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.

33. Fig. 9-13, p. 188

34. Management of Forest Fires (1)
Fire suppression in all types of forests
Increased amounts of underbrush
Increased probability of crown fires

35. Management of Forest Fires (2)
Prescribed fires
Allow some fires to burn
Thin vegetation from forests
Thin around vulnerable homes
Decrease flammability of homes

36. Science Focus: Certifying Sustainably Grown Timber
Forest Steward Council certification of forest operations
Environmentally sound practices
Sustainable yield harvest
Minimal erosion from operations
Retention of dead wood for wildlife habitat

37. Trees and Paper Many trees are cut for paper production Alternatives
Pulp from rice straw and agricultural residues (China)
Kenaf (U.S.)
Hemp

38. Kenaf
Solutions: Pressure to cut trees to make paper could be greatly reduced by planting and harvesting a fest-growing plant known as kenaf. USDA calls kenaf “the best option for paper making in the US”
Fig. 9-14, p. 189

39. Ways to Reduce Tropical Deforestation
Debt-for-nature swaps
Conservation concessions
Gentler logging methods
Encourage use of wood substitutes

40. Solutions Sustaining Tropical Forests Prevention Restoration
Protect the most diverse and
endangered areas
Encourage regrowth
through secondary
succession
Educate settlers about
sustainable agriculture and
forestry
Subsidize only sustainable
forest use
Rehabilitate degraded
areas
Protect forests with
debt-for-nature swaps and
conservation concessions
Figure 9.15: Ways to protect tropical forests and use them more sustainably
(Concept 9-2). Questions: Which three of these solutions do you think are the
most important? Why?
Certify sustainably grown
timber
Reduce poverty
Concentrate farming
and ranching in
already-cleared areas
Slow population growth
Fig. 9-15, p. 190

41. 9-3 How Should We Manage and Sustain Grasslands?
Concept 9-3 We can sustain the productivity of rangeland by controlling the number and distribution of grazing livestock and by restoring degraded grasslands.

42. Grasslands Provide important ecological services
Second most used and altered ecosystem by humans
42% grazed by cattle, sheep, and goats – rangeland (open) and pasture (fenced)
Overgrazing

43. What happens to overgrazed rangeland?
Overgrazed (left) and lightly grazed (right) rangeland
Fig. 9-16, p. 191

44. Manage Rangelands Sustainably
Practice rotational grazing
Fence out riparian zone areas
Suppress invader plants
Herbicides
Mechanical removal
Controlled burning
Short-term trampling

45. In the mid-80s cattle had degraded the vegetation and soil on this stream bank alongside the San Pedro River in Arizona
Fig. 9-17, p. 191

46. Within 10 years, the area was restored through natural regeneration after grazing and off-road vehicle use were banned
Fig. 9-17, p. 191

47. 9-4 How Should We Manage and Sustain Parks and Nature Reserves?
Concept 9-4 We need to put more resources into sustaining existing parks and nature reserves and into protecting much more of the earth’s remaining undisturbed land area.

48. National Parks >1,100 national parks in 120 countries
Only 1% of parks in developing countries are protected
Local people invade parks to survive
Logging
Mining
Poaching

49. Problems Protecting National Parks
Illegal logging
Illegal mining
Wildlife poaching
Most parks too small to protect large animals
Invasion of nonnative species

50. Stresses on U.S. National Parks
58 major national parks
Biggest problem is popularity
Damage from nonnative species
Threatened islands of biodiversity
Need $6 billion for overdue repairs

51. Nature Reserves Occupy a Fraction of Earth
12% of earth’s land protected
Only 5% fully protected – 95% reserved for human use
Need for conservation
Minimum 20% of land in biodiversity reserves
Protection for all biomes

52. Solutions for Protection
“Ecological insurance policy”
Buffer zones around protected areas
Locals to manage reserves and buffer zones
United Nations: 531 biosphere reserves in 105 countries

53. Science Focus: Reintroducing the Gray Wolf to Yellowstone National Park
Reduced to a few hundred in lower 48 by 1973
Keystone species
Restoration proposal angered ranchers, hunters, loggers
reintroduced in Yellowstone, 124 by 2008
Positive ripple effect after reintroduction

54. The Gray Wolf and Yellowstone National Park
: After becoming almost extinct in much of the US, the gray wolf was listed
And protested as an endangered species in Despite intense opposition from ranchers, hunters, miners, and loggers, 31 members of this keystone species were reintroduced to Yellowstone National Park in 1995 and In 2008, there were about 124 gray wolves in the park.
Fig. 9-B, p. 193

55. Case Study: Costa Rica Superpower of biodiversity
Conserved 25% of its land, 8 megareserves
Government eliminated deforestation subsidies
Paid landowners to maintain and restore tree coverage
Boosts ecotourism

56. Costa
Rica
Panama
Figure 9.18: Solutions: Costa Rica has consolidated its parks and reserves into eight zoned megareserves designed to sustain about
80% of the country’s rich biodiversity. Green areas are protected reserves and yellow areas are nearby buffer zones, which can be
used for sustainable forms of forestry, agriculture, hydropower, hunting, and other human activities.
Pacific Ocean
National parkland
Buffer zone
Fig. 9-18, p. 194

57. Protecting Wilderness Protects Biodiversity
Preserves biodiversity
Centers for evolution

58. Case Study: Controversy over Wilderness Protection in the U.S.
1964 Wilderness Act
Ten-fold increase from 1970 to 2008
4.6% of U.S. land protected, 75% of that in Alaska

59. 9-5 How Can We Help to Sustain Terrestrial Biodiversity?
Concept 9-5 We can help to sustain terrestrial biodiversity by identifying and protecting severely threatened areas (biodiversity hotspots), rehabilitating damaged ecosystems (using restoration ecology), and sharing with other species much of the land we dominate (using reconciliation ecology).

60. Three Principles to Protect Ecosystems
Map and inventory the world’s terrestrial and aquatic ecosystems
Locate and protect the most endangered ecosystems, with a focus on biodiversity
Seek to restore as many degraded ecosystems as possible

61. Protecting Global Biodiversity Hotspots
17 megadiversity countries, mostly in tropics and subtropics
Two-thirds of biodiversity
Developing countries economically poor and biodiversity rich
Protect biodiversity hotspots

62. 34 biodiversity hotspots identified by ecologists as important and endangered centers
of terrestrial biodiversity that contain a large number of species found nowhere else.
Identifying and saving these critical habitats requires a vital emergency response.
34 biodiversity hotspots identified by ecologists as important and endangered centers
of terrestrial biodiversity that contain a large number of species found nowhere else.
Identifying and saving these critical habitats requires a vital emergency response.
Fig. 9-19, p. 196

63. Supplement 4, Fig. 2, p. S16

64. Ecological Restoration
Restoration: returning a particular degraded habitat or ecosystem to a condition as similar as possible to its natural state
Rehabilitation: turning a degraded ecosystem into a functional or useful ecosystem without trying to restore it to its original condition ex. Removing pollutants and replanting to reduce soil erosion in abandoned mining sites
Replacement: replacing a degraded ecosystem with another type of ecosystem ex. A degraded forest could be replaced by a pasture or tree plantation
Creating artificial ecosystems: ex. Creating artificial wetlands to help reduce flooding or treat sewage

65. Science-based Principles for Restoration
Identify cause of degradation
Stop abuse by reducing factors
Reintroduce species if necessary
Protect area from further degradation

66. Case Study: Ecological Restoration of Tropical Dry Forest in Costa Rica
One of world’s largest ecological restoration projects
Restore a degraded tropical dry forest and reconnect it to adjacent forests
Involve 40,000 people in the surrounding area – biocultural restoration
Ecotourism

67. Restoration Ecology
Creating new habitats to conserve species diversity in areas where people live, work, play
People learn to protect local species and ecosystems
Sustainable ecotourism
Golden Gate Park in San Francisco

68. Fig. 9-20, p. 198

69. 9-6 How Can We Help to Sustain Aquatic Biodiversity?
Concept 9-6 We can help to sustain aquatic biodiversity by establishing protected sanctuaries, managing coastal development, reducing water pollution, and preventing overfishing.

70. Impacts on Aquatic Ecosystems (1)
Destroyed or degraded by human activities
Coastal habitats disappearing 2-10 times faster than tropical forest
Rising sea levels will destroy coral reefs and some low islands
Ocean floor degradation 150 times larger than area clear-cut annually

71. Impacts on Aquatic Ecosystems (2)
Freshwater habitat disruption
Dams
Water withdrawals from rivers
Likely extinction
34% marine fish species
71% freshwater species
Greater than any other group of species

72. Area of ocean bottom before a trawler net scraped it like a gigantic plow.
Fig. 9-21, p. 199

73. The same area after the trawler scraped the ocean bottom
The same area after the trawler scraped the ocean bottom. According to marine biologist
Ellie Norse, “Bottom trawling is probably the largest human-caused disturbance to the
biosphere.” Trawler fishers disagree and claim that the ocean bottom life recovers after
trawling.
TThe same area after the trawler scraped the ocean bottom. According to marine biologist
Ellie Norse, “Bottom trawling is probably the largest human-caused disturbance to the
biosphere.” Trawler fishers disagree and claim that the ocean bottom life recovers after
trawling.
Fig. 9-21, p. 199

74. Overfishing Fishery Fishprint 157% overfishing
90% of large open-ocean fishes have disappeared since 1950

75. Collapse of Canada’s 500 year old Atlantic cod fishery off coast of Newfoundland
Graph illustrating the collapse of Canada’s 500 year old Atlantic cod fishery off the coast of Newfoundland. Beginning in the late
1950s, fishers used bottom trawlers to capture more of the stock, reflected in the sharp rise in this graph. This resulted in extreme
overexploitation of the fishery, which began a steady fall throughout the 1970s, followed by a slight recovery in the 1980s, and total
collapse by 1992, when the site was closed to fishing. Despite a total ban on fishing, the cod population has not recovered. This has
put at least 20, 000 fishers and fish processors out of work and severely damaged Newfoundland’s economy.
Fig. 9-22, p. 200

76. Case Study: Industrial Fish Harvesting Methods
Trawler fishing
Purse-seine fishing
Longlining
Drift-net fishing

77. Major commercial fishing methods
Fish farming
in cage
Trawler
fishing
Spotter airplane
Sonar
Purse-seine fishing
Drift-net fishing
Figure 9.23: Major commercial fishing methods used to harvest various marine species. These methods have
become so effective that many fish species have become commercially extinct.
Long line fishing
Float
Buoy
lines with
hooks
Deep sea
aquaculture cage
Fish caught
by gills
Fig. 9-23, p. 201

78. Why Is Protection of Marine Biodiversity So Difficult?
Human aquatic ecological footprint expanding
Not visible to most people
Viewed as an inexhaustible resource
Most ocean areas outside jurisdiction of a country

79. Solutions for Marine Ecosystems
Protect endangered and threatened species
Establish protected marine sanctuaries
Marine reserves – work well and quickly
Integrated coastal management
Protect existing coastal wetlands

80. Solutions Managing Fisheries
Fishery Regulations
Bycatch
Set catch limits well below the
maximum sustainable yield
Use wide-meshed nets to
allow escape of smaller fish
Improve monitoring and
enforcement of regulations
Use net escape devices for
seabirds and sea turtles
Economic Approaches
Ban throwing edible and
marketable fish back into
the sea
Sharply reduce or eliminate
fishing subsidies
Aquaculture
Charge fees for harvesting fish
and shellfish from publicly
owned offshore waters
Restrict coastal locations for fish farms
Certify sustainable fisheries
Control pollution more
strictly
Protect Areas
Depend more on
herbivorous fish species
Figure 9.24: Ways to manage fisheries more sustainably and protect marine biodiversity. Questions: Which four of these solutions do
you think are the most important? Why?
Establish no-fishing areas
Establish more marine
protected areas
Nonnative Invasions
Kill organisms in ship ballast water
Rely more on integrated
coastal management
Consumer Information
Filter organisms from ship
ballast water
Label sustainably harvested fish
Dump ballast water far at
sea and replace with
deep-sea water
Publicize overfished and
threatened species
Fig. 9-24, p. 202

81. Three Big Ideas from This Chapter - #1
The economic values of the important ecological services provided by the world’s ecosystems need to be included in the prices of goods and services.

82. Three Big Ideas from This Chapter - #2
We can sustain terrestrial biodiversity by protecting severely threatened areas, restoring damaged ecosystems, and sharing with other species much of the land we dominate.

83. Three Big Ideas from This Chapter - #3
We can sustain aquatic biodiversity by establishing protected sanctuaries, managing coastal development, reducing water pollution, and preventing overfishing.