Chapter 10
Sustaining Terrestrial
Biodiversity: The
Ecosystem Approach
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?
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?
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
•?↓coyotes → ?
↑ ground squirrels,
mice, gophers,
& birds of prey
See next slide
Core Case Study:
Reintroducing Wolves to Yellowstone
Wolves don’t eat small game,
but coyotes do!
 When wolves come back, they
drive away coyotes.


Ranchers nearby are not happy
about re-introducing wolves,
beacsue they do sometimes
prey on farm animals.
Figure 10-1
HUMAN IMPACTS ON
TERRESTRIAL BIODIVERSITY
 We
have depleted
and degraded some
of the earth’s
biodiversity and these
threats are expected
to increase.
 Why?
(2 main reasons)
Figure 10-2
Human Population
Size and resource
use per person.
Human Activities
Agriculture, industry, economic
production and consumption, recreation
Direct Effects
Degradation and destruction Changes in number and
of natural ecosystems
distribution of species
Alteration of natural chemical Pollution of air, water,
cycles and energy flows
and soil
Climate
change
Indirect Effects
Loss of
Biodiversity
Fig. 10-2, p. 192
Ecological Services
 How
much are the earth’s ecological services
worth?

What if humans had to pay for…
…Oxygen?
…Wind?
…the Nitrogen Cycle?
…Photosynthesis?
…Rain?
Ecological Services
In 1997, a team of ecologists, economists, and
geographers estimated the monetary worth of the
earth’s ecological services.
 Their answer:
$33 trillion per year
(≈ total annual “GDP” of the planet)
=$500 trillion total value
=$73,500 for each person on earth
These are considered conservative estimates!
MANAGING AND SUSTAINING
FORESTS
 Forests
provide a
number of ecological
and economic services.
Figure 10-4
Natural Capital
Forests
Ecological
Services
Economic
Services
Support energy flow
and chemical cycling
#1 industry in GA is agriculture
Reduce soil erosion
#1 agricultural industry in GA is
forest products ($29 billion in ’08)
Absorb and release
water
Fuelwood
Purify water and air
Influence local and
regional climate
Store atmospheric
carbon
Provide numerous
wildlife habitats
Lumber
Pulp to make paper
Mining
Recreation
Jobs
Fig. 10-4, p. 193
3 General Types of Forests
 1.
Old-growth forest:
uncut or regenerated forest
that has not been seriously
disturbed for several
hundred years.

22% of world’s forest
(mostly taiga & rainforest)

Hosts many species with
specialized niches.
Figure 10-5
Old Growth Redwoods
East Coast Old-Growth Forest
3 General Types of Forests
 2.
Second-growth forest: a stand of trees
resulting from natural secondary succession.
Next
3 General Types of Forests
 3.
Tree plantation: planted stands of a
particular tree species.
Next
Weak trees
removed
Clear cut
25
30
Seedlings
planted
15
Years of growth
10
5
Fig. 10-6, p. 195
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.
(why?)
 Poor people cut wood
for cooking & heating.
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
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.
½ of total global wood harvest is for fuel
¾ of wood harvest in developing nations is for
fuel
Amy Smith (MIT scientist) has found a way to
make charcoal from bagasse (spent sugarcane),
which used to be discarded.
Haiti
Island of
Hispaniola
Border between Haiti and the
Dominican Republic
Harvesting Trees
 Building
roads into previously inaccessible
forests paves the way for



fragmentation
degradation
destruction
Figure 10-8
Highway
Old
growth
Cleared
plots for
grazing
Highway
Cleared
plots for
agriculture
Fig. 10-8, p. 197
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).
Next
(a) Selective cutting
Fig. 10-9a, p. 198
(b) Clear-cutting
Fig. 10-9b, p. 198
(c) Strip cutting
Uncut
Cut 1
year ago
Dirt road
Cut 3–10
years ago
Uncut
Stream
Fig. 10-9c, p. 198
Sections of Clearcut Forest
near Mt. Hood, Oregon
Clearcut Forest
in Nevada County, California
Harvesting Trees
Effects of clear-cutting in the
state of Washington, U.S.
Figures 10-10 and 10-11
Trade-Offs
Clear-Cutting Forests
Advantages
Disadvantages
Higher timber yields
Reduces biodiversity
Maximum profits in
shortest time
Disrupts ecosystem
processes
Can reforest with fastgrowing trees
Destroys and
fragments wildlife
habitats
Short time to establish
new stand of trees
Leaves large openings
Needs less skill and
planning
Good for tree species
needing full or
moderate sunlight
(such as pine trees!)
Increases water
pollution, flooding, and
erosion on steep
slopes
Eliminates most
recreational value
Fig. 10-11, p. 198
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
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 (a la FSC)
• 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
CASE STUDY: FOREST RESOURCES AND
MANAGEMENT IN THE U.S.
(Good News/Bad News)
 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.
Types and Effects of Forest Fires
Surface fire
*Many benefits
*Large trees are fireresistant
→In GA, longleaf pine
and live oak
Crown fire
*Total destruction
→may even burn away all
organic matter from soil,
requiring >500 yrs to
recover via primary
succession
Figure 10-13
Crown Fire
Crown Fire
Surface Fire
Surface Fire
Ground Fire
Types and Effects of Forest Fires
 Depending
on their intensity, fires can benefit
or harm forests.
 Burn away flammable ground material,
preventing more severe fires later.
 Release valuable mineral nutrients.
 Allow some seeds to germinate.
 Create open spaces for wildlife such as
deer, bears, and many types of plants.
Figure 10-13
Solutions:
Controversy Over Fire Management
 To



reduce damage from severe fires:
Set controlled surface fires to burn away
accumulated debris
Allow fires to burn on public lands if they don’t
threaten life and property.
Clear small areas around property subject to fire.
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 fireprone trees and underbrush.
Some forest scientists believe this could increase
severe fires by removing fire resistant (large)
trees and leaving highly flammable slash
(branches on ground after timber harvest)
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
Trade-Offs
Logging in U.S. National Forests
Advantages
Disadvantages
Helps meet country’s
timber needs
Provides only 4% of timber
needs
Cut areas grow back
Ample private forest land
to meet timber needs
Keeps lumber and
paper prices down
slightly
Has little effect on timber
and paper prices
Provides jobs in
nearby communities
Promotes economic
growth in nearby
communities
Damages nearby rivers and
fisheries
Recreation in national
forests provides more local
jobs and income for local
communities than logging
Decreases recreational
opportunities
Fig. 10-14, p. 202
Solutions:
Reducing Demand for Tree Harvest
 Tree
harvesting can
be reduced by
wasting less wood
and making paper
and charcoal fuel
from fibers that do
not come from trees.
Georgia is
among the
top US
producers!

Kenaf is a promising
plant for paper
production.
Figure 10-15
American Forests in a Globalized
Economy
 Timber
from tree plantations in temperate
and tropical foreign 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 oldgrowth 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.
CASE STUDY: TROPICAL
DEFORESTATION
1975
 Satellite

2001
images of Rhondonia, Brazil.
remote sensing is an important tool used
by ecologists
Next
TROPICAL DEFORESTATION
1975

2001
Large areas of ecologically and economically
important tropical forests are being cleared and
degraded at a fast rate.
 Can you see the effect of new roads in this image?
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.
Figure 10-17
TROPICAL DEFORESTATION
 It
is estimated that we currently have half of the
“original” modern-era tropical forest remaining,
most losses occurring since 1950.
 Current global tropical forest losses are
estimated to be between 50,000 to 170,000 km2
per year.
= 14 to 48 football fields per hour
 At this rate, half of the remaining tropical forest
will be gone in 35-117 years.
Figure 10-17
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.
Rosy periwinkle
Cathranthus roseus,
Madagascar
Hodgkin's disease,
lymphocytic leukemia
Fig. 10-18e, p. 205
Rauvolfia
Rauvolfia sepentina,
Southeast Asia
Tranquilizer, high
blood pressure
medication
Fig. 10-18a, p. 205
Cinchona
Cinchona ledogeriana,
South America
Quinine for malaria treatment
Fig. 10-18d, p. 205
Neem tree
Azadirachta indica,
India
Timber, treatment of many
diseases, insecticide,
spermicide
Fig. 10-18f, p. 205
Foxglove
Digitalis purpurea,
Europe
Digitalis for heart failure
Fig. 10-18b, p. 205
Pacific yew
Taxus brevifolia,
Pacific Northwest
Ovarian cancer
Fig. 10-18c, p. 205
Causes of Tropical Deforestation and
Degradation
 Tropical
deforestation
results from a
number of
interconnected
primary and
secondary causes.
Figure 10-19
Why are the
world’s
rainforests being
degraded &
destroyed?
• Oil drilling
• Mining
• Flooding from dams
• Tree plantations
• Cattle ranching
• Cash crops
• Settler farming
• Fires
• Logging
• Roads
Direct Causes
• Not valuing
ecological services
• Exports
• Government policies
• Poverty
• Population growth
Indirect Causes
Fig. 10-19, p. 206
Solutions
Sustaining Tropical Forests
Prevention
Protect most diverse and endangered
areas
Restoration
Reforestation
Educate settlers about sustainable
agriculture and forestry
Phase out subsidies that encourage
unsustainable forest use
Add subsidies that encourage
sustainable forest use
Rehabilitation of degraded
areas
Protect forests with debt-for-nature
swaps and conservation easements
Certify sustainably grown timber
Reduce illegal cutting
Reduce poverty
Slow population growth
Concentrate farming and
ranching on already-cleared
areas
Fig. 10-20, p. 207
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.
Read about her
on p. 230!
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.
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
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
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.
NATIONAL PARKS AROUND THE
WORLD
 Globally,
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.
Case Study: Stresses on U.S.
National Parks
 Overused
due to
popularity.
 Inholdings (private
ownership) within
parks threaten
natural resources.
 Air pollution.
 Lack of $$$
 Invasive Species
Figure 10-23
 Suggestions
for
sustaining and
expanding the
national park
system in the
U.S.
Next
Solutions
National Parks
• Integrate plans for managing parks and nearby
federal lands
• Add new parkland near threatened parks
• Buy private land (“inholdings”) 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
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.
NATURE RESERVES
 Large
and medium-sized reserves with buffer
zones help protect biodiversity and can be
connected by habitat corridors a.k.a. wildlife
corridors. These corridors effectively increase
the size of the protected habitat.
 Costa
Rica has
consolidated its parks
and reserves into 8
megareserves
designed to sustain
80% if its biodiversity.
Figure 10-10B
Guanacaste
Nigaragua
Caribbean Sea
Llanuras de
Tortuguero
Costa
Rica
Arenal
Bajo
Tempisque
La Amistad
Panama
Cordillera Volcanica Central
Pacifico Central
Peninsula Osa
Pacific Ocean
Fig. 10-B, p. 213
NATURE RESERVES
A
model biosphere
reserve that contains a
protected inner core
surrounded by two
buffer zones that
people can use for
multiple uses.
 Even researchers
would only be allowed
into the core area
occasionally.
Biosphere Reserve
Core area
Buffer zone 1
Buffer zone 2
Tourism and
education center
Human
Settlements
Research
Station
Fig. 10-25, p. 214
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.
GPS devices gather data to put into GIS
databases
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.

34 global hotspots identified by ecologists as important and
endangered centers of biodiversity.
Figure 10-26
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.
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.
ECOLOGICAL RESTORATION
 Five
basic science-based steps for ecological
restoration:
1.
2.
3.
4.
5.
Identify cause.
Stop abuse by eliminating or sharply reducing
factors.
Reintroduce species if necessary.
Protect area from further degradation.
Use adaptive management to monitor efforts,
assess successes, and modify strategies.
Will Restoration Encourage Further
Destruction?
 There
is some concern that ecological
restoration could promote further
environmental destruction and degradation.
Why?
•Suggesting that any ecological harm can be
undone.
•Preventing ecosystem damage is far cheaper
than ecological restoration.
WHAT CAN WE DO?

Eight priorities for protecting biodiversity:
1. Take immediate action to preserve world’s
biological hot spots.
2. Keep intact remaining old growth.
3. Complete mapping of world’s biodiversity for
inventory and decision making.
4. Determine world’s marine hot spots.
5. Concentrate on protecting and restoring lake
and river systems (most threatened
ecosystems).
WHAT CAN WE DO?
6. Ensure that the full range of the earths
ecosystems are included in global conservation
strategy.
7. Make conservation profitable.
8. Initiate ecological restoration projects to heal
some of the damage.
Reconciliation Ecology:
Living with other species
 With
only 5% of the earth currently protected,
we need to learn to live WITH other species
 Reconciliation
ecology focuses on
establishing and maintaining new habitats to
maintain biodiversity in places where people
live, work, and play
Reconciliation Ecology

Protect butterflies and bees (critical pollinators)



Communities agree to reduce use of pesticides on lawns,
fields, golf courses, and parks
Neighborhoods work together to plant gardens of
flowering plants to support pollinator populations
Build bee and butterfly habitats
Reconciliation Ecology
 Maintain
bat boxes for control of flies and
mosquitos
Reconciliation Ecology
 Growing


rooftop gardens
Provides habitat
Saves energy
• Provides insulation
• Cools cities
• Conserves water
Rooftop
Garden
Design
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 (FSA certified)
• 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