Download Chapter 10

Sustaining Terrestrial Biodiversity:
The Ecosystem Approach
Chapter 10
Standard 8: Students will know how water resources are used globally.
Standard 29: Students will understand the environmental impact of fishing.
Standard 26: Students will know the major types of public and federal lands.
Standard 40: Students will know the causes and consequences of the loss of biodiversity.
Core Case Study: Reintroducing
Gray Wolves to Yellowstone
 Around 1800
 1850–1900: decline due to
human activity
 U.S. Endangered Species Act:
1973
 1995–1996: relocation of gray
wolves to Yellowstone Park
 2008: Gray wolf no longer
protected
 What do you think would be the biggest threats
to forest ecosystems?
What Are the Major Threats
to Forest Ecosystems?
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Unsustainable cutting
Burning
Diseases
Insects
Tropical deforestation
Forests Vary in Their Make-Up,
Age, and Origins
 Old-growth or primary forest
• Uncut or regenerated primary forest not disturbed
by human activity or natural disaster for more
than 200 years
• 36% of world’s forests
Oldgrowth European
Beech forest
in Biogradska
Gora National
Park, Montenegr
o
Coast Redwoods in old-growth forest inMuir Woods
National Monument, Marin County, California.
http://upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Biogradska_suma.jpg/300px-Biogradska_suma.jpg
Forests Vary in Their Make-Up,
Age, and Origins
 Second-growth
forest: trees
resulting from
secondary
ecological
succession
• 60% of world’s
forests
http://www.seattle.gov/util/groups/public/@spu/documents/we
bproductionfile/02_013762.jpg
Fig. 10-3a, p. 216
Forests Vary in Their Make-Up,
Age, and Origins
 Tree plantation,
tree farm or
commercial
forest: managed
tract of uniformly
aged trees
• 4% of world’s
forests
• May supply
most of the
industrial wood
in the future
A pine plantation in the United States. Tree
plantations are usually easily distinguished
from natural forests by the trees being
planted in straight lines.
http://upload.wikimedia.org/wikipedia/commons/thumb/6/63/Pinus_ta
eda_plantation.jpg/220px-Pinus_taeda_plantation.jpg
Fig. 10-4, p. 217
Science Focus: Putting a Price Tag on
Nature’s Ecological Services
 Forests valued for ecological services
•
•
•
•
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Nutrient cycling
Climate regulation
Erosion control
Waste treatment
Recreation
Raw materials
 $4.7 Trillion per year
Unsustainable Logging is a Major Threat
to Forest Ecosystems
 Increased erosion
 Sediment runoff into
waterways
 Habitat fragmentation
 Loss of biodiversity
http://2.bp.blogspot.com/63LjuJ2tybA/Tyqp8s2MyiI/AAAAAAAAITU/pK_-JHBUUE/s1600/000.jpeg
Unsustainable Logging is a Major Threat
to Forest Ecosystems
 Major tree harvesting methods:
• Selective cutting: intermediate aged or mature
trees in an uneven-aged forest are cut singly or in
small groups
• Clear-cutting: all trees removed from an area
• Strip cutting: clear cutting a strip of trees along
the contour of the land within a corridor narrow
enough to allow natural regeneration within a few
years
TRADE-OFFS
Clear-Cutting Forests
Advantages
Disadvantages
Higher timber
yields
Reduces
biodiversity
Maximum profits
in shortest time
Destroys and
fragments wildlife
habitats
Can reforest with
fast-growing trees
Good for tree
species needing
full or moderate
sunlight
Increases water
pollution, flooding,
and erosion on
steep slopes
Eliminates most
recreational value
Fig. 10-8, p. 220
Invasion
• Nonnative
pests
• Disease
• Wildlife
species
Insects and Climate Change Can
Threaten Forest Ecosystems
 Introduction of foreign diseases and insects
• Accidental
• Deliberate
 Global warming
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•
•
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Rising temperatures
Trees more susceptible to diseases and pests
Drier forests: more fires
More greenhouse gases
Fire Can Threaten Forest Ecosystems
 Surface fires
• Usually burn leaf litter and undergrowth
• May provide food in the form of vegetation that
sprouts after fire
http://www.nps.gov/ngpfire/Photos/jeca_ht_08.JPG
Fire Can Threaten Forest Ecosystems
 Crown fires
• Extremely hot: burns whole trees
• Kill wildlife
• Increase soil erosion
http://www.meto.umd.edu/~zli/Info/crown_firecopy%20copy.jpg
We Have Cut Down Almost Half
of the World’s Forests
 Deforestation
• Tropical forests
• Especially in Latin America, Indonesia, and Africa
• Boreal forests
http://milwaukeecountyfirst.com/wpcontent/uploads/2010/05/deforestati
on.jpg
• Especially in Alaska, Canada, Scandinavia, and
Russia
http://media.treehugger.com/assets/images/2013/05/defore
station_in_the_amazon.jpg.662x0_q100_crop-scale.jpg
Fig. 10-12, p. 223
Case Study: Many Cleared Forests in the
United States Have Grown Back
 Forests of the eastern United States decimated
between 1620 and 1920
 Grown back naturally through secondary
ecological succession
 Biologically simplified tree plantations reduce
biodiversity
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
Cattle
ranching
• Roads
• Fires
• Settler farming
• Cash crops
Tree
plantations
• Cattle ranching
• Logging
• Tree plantations
Logging
Cash crops
Settler
farming
Roads
Fires
Fig. 10-15, p. 225
Tropical Forests are Disappearing
Rapidly
 Majority of loss since 1950
 Brazil and Indonesia tropical forest loss
 Role of deforestation in species’ extinction
http://www.foodbeautylove.com/wp-content/uploads/2012/10/Rainforest-Deforestation.jpg
http://mongabay-images.s3.amazonaws.com/13/AMAZON-DEFORESTATION-full.jpg
How Should We Manage and
Sustain Forests
 Emphasize the economic value of their
ecological services
 Protect old-growth forests
 Harvest trees no faster than they are
replenished
 Use sustainable substitute resources.
Fig. 10-17, p. 227
We Can Improve the Management
of Forest Fires
 The Smokey Bear educational
campaign
 Prescribed fires
 Allow fires on public lands to burn
 Protect structures in fire-prone areas
 Thin forests in fire-prone areas
Smokey the Bear Campaign
We Can Improve the Management
of Forest Fires
 2003 Healthy Forests Restoration Act
• Allows timber companies to cut down
economically valuable medium size and large
trees in 71% of the country’s national forests in
return for clearing away smaller, more fire prone
trees and underbrush
• Companies NOT required to do prescribed burns
• Thinning projects exempt from environmental
review
• Criticized for NOT following known management
techniques
Science Focus: Certifying Sustainably
Grown Timber
 Collins Pine
• Owns and manages protective timberland
 Forest Stewardship Council
• Nonprofit
• Developed list of environmentally sound practices
• Certifies timber and products
We Can Reduce the Demand for
Harvested Trees
 Up to 60% of the wood used in the U.S. is
wasted unnecessarily
 Improve the efficiency of wood use
 Make tree-free paper
• Rice straw used in China
• Kenaf
• Hemp
Case Study: Deforestation and the
Fuelwood Crisis
 Possible solutions
• Establish small plantations of fast-growing
fuelwood trees and shrubs
• Burn wood more efficiently
• Solar or wind-generated electricity
 Haiti: ecological disaster: only 2% of it’s land is
left forested, soils have eroded
 South Korea: model for successful reforestation
Governments and Individuals Can Act
to Reduce Tropical Deforestation
 Reduce fuelwood demand
 Practice small-scale sustainable agriculture and
forestry in tropical forest
 Debt-for-nature swaps
 Conservation concessions
 Use gentler logging methods
 Buy certified lumber and wood products
Individuals Matter: Wangari Maathari and
Kenya’s Green Belt Movement
 Green Belt Movement:
1977
• Self-help group of
women in Kenya
• Women paid for each
seedling planted that
survives
 Nobel Peace Prize: 2004
 Pygmy tribes
in Africa
have been
given GPS
units to help
them fight
logging and
poaching in
their area
http://www.newscien
tist.com/blogs/onepe
rcent/2012/02/21/1.j
pg
http://comingworldwar3.files.
wordpress.com/2010/06/bre
e-keyton-and-the-pygmies600x450.jpg
How Should We Manage and
Sustain Grasslands
 Concept 10-3 We can sustain the productivity
of grasslands by controlling the number and
distribution of grazing livestock and restoring
degraded grasslands.
Some Rangelands Are Overgrazed
 Important ecological services of grasslands
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Soil formation
Erosion control
Nutrient cycling
Storage of atmospheric carbon dioxide in
biomass
• Maintenance of diversity
Some Rangelands are Overgrazed
 Overgrazing of rangelands
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Reduces grass cover
Leads to erosion of soil by water and wind
Soil becomes compacted
Enhances invasion of plant species that cattle
won’t eat
Fig. 10-20, p. 232
Fig. 10-21a, p. 233
We Can Manage Rangelands More
Sustainably
 Rotational grazing
 Suppress growth of invasive species
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Herbicides
Mechanical removal
Controlled burning
Controlled short-term trampling
We Can Manage Rangelands More
Sustainably
 Replant barren areas
 Apply fertilizer
 Reduce soil erosion
Fig. 10-21b, p. 233
Rangeland Management Purposes
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Produces forage for livestock
Habitat for many wildlife species
Protects soil from erosion
Germplasm bank
• Germplasm: The genetic material, especially its specific
molecular and chemical constitution, that carries the
inherited characteristics of an organism from one
generation to the next by means of the germ cells
 Purifies and enhances the environment
 Recreation
 Brainstorm with a partner, groups who support each
purpose and why – Fill in worksheet
Case Study: Grazing and Urban
Development the American West
 American southwest: population surge since
1980
 Land trust groups: limit land development
 Reduce the harmful environmental impact of
herds
• Rotate cattle away from riparian areas
• Use less fertilizers and pesticides
• Operate ranch more economically
10-4 How Should We Manage and Sustain
Parks and Natural Reserves?
 Concept 10-4 Sustaining biodiversity will
require protecting much more of the earth’s
remaining undisturbed land area as parks and
nature reserves.
National Parks Face Many Environmental
Threats
 Worldwide: 1100 major national parks
 Parks in developing countries
• Greatest biodiversity
• 1% protected against
• Illegal animal poaching
• Illegal logging and mining
Fig. 10-23, p. 236
Case Study: Stresses on U.S.
Public Parks
 58 Major national parks in the U.S.
 Biggest problem may be popularity
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Noise
Congestion
Pollution
Damage or destruction to vegetation and wildlife
 Repairs needed to trails and buildings
Science Focus: Effects of Reintroducing the
Gray Wolf to Yellowstone National Park
 Gray wolves prey on elk and push them to a
higher elevation
• Regrowth of aspen, cottonwoods, and willows
• Increased population of riparian songbirds
 Reduced the number of coyotes
• Fewer attacks on cattle
 Wolf pups susceptible to parvovirus carried by
dogs
Nature Reserves Occupy Only a Small
Part of the Earth’s Land
 Conservationists’ goal: protect 20% of the
earth’s land
 Cooperation between government and private
groups
 Nature Conservancy
 Eco-philanthropists
 Developers and resource extractors opposition
Designing and Connecting Nature
Reserves
 Large versus small reserves
 The buffer zone concept
• United Nations: 529 biosphere reserves in 105
countries
 Habitat corridors between isolated reserves
• Advantages
• Disadvantages
Case Study: Costa Rica—A Global
Conservation Leader
 1963–1983: cleared much of the forest
 1986–2006: forests grew from 26% to 51%
• Goal: to reduce net carbon dioxide emissions to
zero by 2021
 Eight zoned megareserves
• Designed to sustain around 80% of Costa Rica’s
biodiversity
Protecting Wilderness Is an Important
Way to Preserve Biodiversity
 Pros
 Cons
Case Study: Controversy over Wilderness
Protection in the United States
 Wilderness Act of 1964
 How much of the United States is protected
land?
 Roadless Rule
 2005: end of roadless areas within the national
forest system
10-5 What is the Ecosystem Approach
to Sustaining Biodiversity? (1)
 Concept 10-5A We can help sustain
biodiversity by identifying severely threatened
areas and protecting those with high plant
diversity and those where ecosystem services
are being impaired.
 Concept 10-5B Sustaining biodiversity will
require a global effort to rehabilitate and restore
damaged ecosystems.
10-5 What is the Ecosystem Approach
to Sustaining Biodiversity? (2)
 Concept 10-5C Humans dominate most of the
earth’s land, and preserving biodiversity will
require sharing as much of it as possible with
other species.
We Can Use a Four-Point Strategy
to Protect Ecosystems
 Map global ecosystems; identify species
 Locate and protect most endangered species
 Restore degraded ecosystems
 Development must be biodiversity-friendly
 Are new laws needed?
Protecting Global Biodiversity Hot Spots
Is an Urgent Priority
 1988: Norman Myers
• Identify biodiversity hot spots rich in plant species
 Not sufficient public support and funding
 Drawbacks of this approach
• May not be rich in animal diversity
• People may be displaced and/or lose access to
important resources
Fig. 10-26, p. 241
Fig. 10-27, p. 241
Case Study: A Biodiversity Hot Spot
in East Africa
 Eastern Arc Mountains of Tanzania, Africa
• Highest concentration of endangered species on
earth
 Threatened due to
• Killing of forests by farmers and loggers
• Hunting
• Fires
Protecting Ecosystem Services Is
Also an Urgent Priority
 U.N. Millennium Ecosystem Assessment: 2005
• Identify key ecosystem services
• Human activities degrade or overuse 62% of the
earth’s natural services
 Identify highly stressed life raft ecosystems
We Can Rehabilitate and Restore
Ecosystems That We Have Damaged (1)
 Study how natural ecosystems recover
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Restoration
Rehabilitation
Replacement
Creating artificial ecosystems
We Can Rehabilitate and Restore
Ecosystems That We Have Damaged (2)
 How to carry out most forms of ecological
restoration and rehabilitation
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Identify what caused the degradation
Stop the abuse
Reintroduce species, if possible
Protect from further degradation
Fig. 10-29, p. 245
Science Focus: Ecological Restoration of
a Tropical Dry Forest in Costa Rica
 Guanacaste National Park restoration project
• Relinked to adjacent rain forest
• Bring in cattle and horses – aid in seed dispersal
• Local residents – actively involved
Will Restoration Encourage Further
Destruction?
 Preventing ecosystem damage is cheaper than
restoration
 About 5% of the earth’s land is preserved from
the effects of human activities
We Can Share Areas We Dominate With
Other Species
 Win-Win Ecology: How Earth’s Species Can
Survive in the Midst of Human Enterprise, by
Michael L. Rozenweig, 2003
• Reconciliation or applied ecology
• Community-based conservation
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Belize and the black howler monkeys
Protect vital insect pollinators
Bluebird protection with special housing boxes
Berlin, Germany: rooftop gardens
San Francisco: Golden Gate Park
Case Study: The Blackfoot Challenge—
Reconciliation Ecology in Action
 1970s: Blackfoot River Valley in Montana
threatened by
• Poor mining, logging, and grazing practices
• Water and air pollution
• Unsustainable commercial and residential
development
 Community meetings led to
• Weed-pulling parties
• Nesting structures for waterfowl
• Developed sustainable grazing systems