Sustaining Biodiversity: The Ecosystems Approach

1
Chapter 6

• Sustaining Biodiversity The Ecosystems Approach

2
Chapter Overview Questions

• How have human activities affected the earths
  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 (contd)

• 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 earths
  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 books e-resources page at
  www.thomsonedu.com 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
• 1850-1900 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 earths
  biodiversity and these threats are expected to
  increase.

7
Human Population
Size and resource use
Human Activities
Agriculture, industry, economic production and
consumption, recreation
Direct Effects
Changes in number and distribution of species
Degradation and destruction of natural ecosystems
Alteration of natural chemical cycles and energy
flows
Pollution of air, water, and soil
Indirect Effects
Loss of Biodiversity
Climate change
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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
Natural Capital
Forests
Economic Services
Ecological 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 Live
stock grazing Recreation Jobs
11
Types of Forests

• Old-growth forest uncut or regenerated forest
  that has not been seriously disturbed for several
  hundred years.
• 22 of worlds forest.
• Hosts many species with specialized niches.

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Types of Forests

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

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Weak trees removed
Clear cut
Seedlings planted
25
15
10
30
Years of growth
5
14
Global Outlook Extent of Deforestation

• Human activities have reduced the earths forest
  cover by as much as half.
• Losses are concentrated in developing countries.

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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
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.

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Harvesting Trees

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

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Cleared plots for grazing
Highway
Highway
Cleared plots for agriculture
Old growth
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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).

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(a) Selective cutting
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(b) Clear-cutting
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(c) Strip cutting
Uncut
Cut 1 year ago
Dirt road
Cut 310 years ago
Uncut
Stream
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Harvesting Trees
Effects of clear-cutting in the state of
Washington, U.S.
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Trade-Offs
Clear-Cutting Forests
Disadvantages
Advantages
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
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
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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.

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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
28
CASE STUDY FOREST RESOURCES AND MANAGEMENT IN
THE U.S.

• U.S. forests cover more area than in 1920.
• Since the 1960s, 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.

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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.

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Solutions Controversy Over Fire Management

• To reduce fire damage
• Set controlled surface fires.
• Allow fires to burn on public lands if they dont
  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.

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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.

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Trade-Offs
Logging in U.S. National Forests
Disadvantages
Advantages
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
Helps meet countrys timber needs Cut areas
grow back Keeps lumber and paper prices
down Provides jobs in nearby communities Promo
tes economic growth in nearby communities
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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 worlds 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 blood pressure
medication
41
Foxglove Digitalis purpurea, Europe Digitalis
for heart failure
42
Pacific yew Taxus brevifolia, Pacific
Northwest Ovarian cancer
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Cinchona Cinchona ledogeriana, South
America Quinine for malaria treatment
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Rosy periwinkle Cathranthus roseus,
Madagascar Hodgkin's disease, lymphocytic
leukemia
45
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
Oil drilling Mining Flooding from dams
Tree plantations Cattle ranching Cash crops
Settler farming Fires Logging Roads
Secondary Causes
Not valuing ecological services Exports
Government policies Poverty Population growth
Basic Causes
48
Solutions
Sustaining Tropical Forests
Restoration
Prevention
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
49
Kenyas Green Belt MovementIndividuals 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 worlds 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
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
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 earths land area is protected.
• Only 5 is strictly protected from harmful human
  activities.
• Conservation biologists call for full protection
  of at least 20 of earths 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.

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Caribbean Sea
Guanacaste
Nigaragua
Llanuras de Tortuguero
Costa Rica
La Amistad
Arenal
Bajo Tempisque
Panama
Cordillera Volcanica Central
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.

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Biosphere Reserve
Core area
Buffer zone 1
Buffer zone 2
Research Station
Human Settlements
Tourism and education center
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.

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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 worlds
  biological hot spots.
• Keep intact remaining old growth.
• Complete mapping of worlds biodiversity for
  inventory and decision making.
• Determine worlds marine hot spots.
• Concentrate on protecting and restoring lake and
  river systems (most threatened ecosystems).

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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
  earths land and water allotted to the rest of
  nature.

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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.