Sustaining Terrestrial Biodiversity: The Ecosystem Approach

1
Chapter 10

• Sustaining Terrestrial Biodiversity The
  Ecosystem Approach

2
Chapter Overview Questions

• How have human activities affected the earths
  biodiversity?
• Why should we care about Biodiversity?
• Whats the natural capital involved with Forests?
• What are the characteristics of the different
  ages of forests?
• What are the different tree harvesting methods
  and which more sustainable?

3
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.

Figure 10-1
4
HUMAN IMPACTS ON TERRESTRIAL BIODIVERSITY

• We have depleted and degraded some of the earths
  biodiversity and these threats are expected to
  increase.

Figure 10-2
5
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
Fig. 10-2, p. 192
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Why Should We Care About Biodiversity?

• Biodiversity has two types of value
• Intrinsic We care because these components
  exist, regardless of use.
• Instrumental We care because of the usefulness
  to us in the form of economic and ecological
  services.

Figure 10-3
7
Why should we care about biodiversity?

• Biodiversity also helps maintain the structure
  and function of the ecosystem.
• Yellowstone Gray Wolf
• Instrumental Value take two forms
• Use Value benefits us in the form of economic
  goods and services, ecological services,
  recreation, scientific information, and
  preservation.
• Nonuse Value Similar to intrinsic value but can
  takes into consideration Aesthetics.

8
MANAGING AND SUSTAINING FORESTS

• Forests provide a number of ecological and
  economic services that researchers have attempted
  to estimate their total monetary value.

Figure 10-4
9
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
Fig. 10-4, p. 193
10
Types of Forests

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

Figure 10-5
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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.

Figure 10-6
12
Weak trees removed
Clear cut
Seedlings planted
25
15
10
30
Years of growth
5
Fig. 10-6, p. 195
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Global Outlook Extent of Deforestation

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

Figure 10-7
14
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
migratory species such as birds and
butterflies Regional climate change from
extensive clearing Release of CO2 into
atmosphere Acceleration of flooding
Fig. 10-7, p. 196
15
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).

Figure 10-9
16
(a) Selective cutting
Fig. 10-9a, p. 198
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(b) Clear-cutting
Fig. 10-9b, p. 198
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(c) Strip cutting
Uncut
Cut 1 year ago
Dirt road
Cut 310 years ago
Uncut
Stream
Fig. 10-9c, p. 198
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Harvesting Trees
Effects of clear-cutting in the state of
Washington, U.S.
Figures 10-10 and 10-11
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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
Fig. 10-11, p. 198
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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.

Figure 10-12
22
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
of forest 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
Fig. 10-12, p. 199
23

• STOP HERE

24
Questions for Today

• What are the basic parts of fire?
• What are the different types of forest fires?
• Who is Smokey?
• Are all Forest Fires bad?
• What is the Healthy Forest Restoration Act?

25
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.

Figure 10-13
27
Fire Traingle

• Science Behind Fire
• There are three parts to make fire.
• Fuel
• Heat
• Oxygen
• Usually Forest Wildfires have an overabundance of
  fuel which leads to uncontrolled burns.

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Three Types of Fires

• Surface Fires
• Usually burn undergrowth and leaf litter on the
  forest floor.
• Kills seedling and small trees but not mature,
  old growth trees.
• Benefits
• Burn away flammable ground material
• Release valuable nutrients
• Release seeds
• Open up habitats for new species of fauna

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Types of Fires

• Crown Fires
• Extremely Hot
• May start from the ground, but eventually burn
  the whole tree
• Usually occur from forest that have not had any
  surface fires for decades.
• Ground Fires
• Surface fires that go underground
• Burns decayed leaves and peat
• Can burn and smolder for days before being
  noticed.

30
Solutions Controversy Over Fire Management

• Back in World War II, the US Government
  Introduced Smokey Bear to the population to
  increase awareness of Forest Fires.
• Smokey Bears Tagline
• Only YOU can prevent Forest Fires
• It helped convince that all Forest Fires are bad
  and should be extinguished.
• Led 40 of forest being threatened by wildfires.
• Why?

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Solutions Controversy Over Fire Management

• Preventing all forest fires leads to an
  accumulation of leaf litter or highly flammable
  logging debris called slash.
• Ecologist have proposed several strategies for
  reducing fire-related harm
• Prescribed fires
• Setting small, contained surface fires in high
  risk forest areas.
• Biological Prevention
• Using grazing animals to eat away at the
  underbrush.

32
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.

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• STOP

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Questions for Today

• How should National Forests be used?
• How do we degrade Tropical Rainforests?
• How do we manage and sustain Grassland areas?
• What are ways the government have protected
  Terrestrial Ecosystems?
• What can you do to maintain and sustain
  Terrestrial Ecosystems?

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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.

Figure 10-14
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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
Fig. 10-14, p. 202
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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.

Figure 10-15
38
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.

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CASE STUDY TROPICAL DEFORESTATION

• Large areas of ecologically and economically
  important tropical forests are being cleared and
  degraded at a fast rate.

Figure 10-16
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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.

Figure 10-17
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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.

Figure 10-18
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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
Fig. 10-20, p. 207
43
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.

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MANAGING AND SUSTAINING GRASSLANDS

• Overgrazing (left) occurs when too many animals
  graze for too long and exceed carrying capacity
  of a grassland area.

Figure 10-21
45
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.

Figure 10-22
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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.

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Case Study Stresses on U.S. National Parks

• Overused due to popularity.
• Inholdings (private ownership) within parks
  threaten natural resources.
• Air pollution.

Figure 10-23
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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
Fig. 10-24, p. 211
49
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.

50
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.

Figure 10-10B
51
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.
• Wilderness Act

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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.

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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).

54
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.
Fig. 10-27, p. 219